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Sample records for caspase-8 isoform caspase-8s

  1. Ripoptosome Analysis by Caspase-8 Coimmunoprecipitation.

    Science.gov (United States)

    Feoktistova, Maria; Geserick, Peter; Leverkus, Martin

    2016-01-01

    The biochemical signaling of cell death pathways is executed at a number of different intracellular and/or membrane-bound high-molecular mass complexes. It is crucial to be able to detect the formation, differences in assembly, and differential composition of such complexes to understand their contribution to the execution phase of apoptotic or necroptotic cell death. We describe here the use of caspase-8 coimmunoprecipitation in the spontaneously transformed keratinocyte cell line, HaCaT, to study the formation and composition of the Ripoptosome, a complex that is based on the serine-threonine kinase receptor-interacting protein 1 (RIPK1). However, the method can be adapted for use with other antibodies and cell lines. This protocol determines whether cells form the Ripoptosome complex, which is important for both apoptosis and necroptosis execution. Caspase-8 is an indispensible Ripoptosome component; therefore, caspase-8 antibodies are used to pull down the respective complex. However, the method cannot discriminate whether this complex triggers apoptosis (through the RIPK1 → FADD → caspase-8 activation pathway), necroptosis (through the RIPK1 → RIPK3 → MLKL activation pathway) or nondeath signaling. The actual signaling output (death or nondeath signaling) depends on the stoichiometry of the respective molecules as well as on the activity of FLIP, caspase-8, or other factors. PMID:26933246

  2. Proteasomal regulation of caspase-8 in cancer cell apoptosis

    OpenAIRE

    Fiandalo, Michael V.; Schwarze, Steven R.; Kyprianou, Natasha

    2013-01-01

    Previous studies demonstrated that proteasome inhibition sensitizes TRAIL resistant prostate cancer cells to TRAIL-mediated apoptosis via stabilization of the active p18 subunit of caspase-8. The present study investigated the impact of proteasome inhibition on caspase-8 stability, ubiquitination, trafficking, and activation in cancer cells. Using caspase-8 deficient neuroblastoma (NB7) cells for reconstituting non-cleavable mutant forms of caspase-8, we demonstrated that the non-cleavable fo...

  3. The marine lipopeptide somocystinamide A triggers apoptosis via caspase 8

    OpenAIRE

    Wrasidlo, Wolf; Mielgo, Ainhoa; Torres, Vicente A; Barbero, Simone; Stoletov, Konstantin; Suyama, Takashi L.; Klemke, Richard L.; Gerwick, William H.; Carson, Dennis A.; Stupack, Dwayne G.

    2008-01-01

    Screening for novel anticancer drugs in chemical libraries isolated from marine organisms, we identified the lipopeptide somocystinamide A (ScA) as a pluripotent inhibitor of angiogenesis and tumor cell proliferation. The antiproliferative activity was largely attributable to induction of programmed cell death. Sensitivity to ScA was significantly increased among cells expressing caspase 8, whereas siRNA knockdown of caspase 8 increased survival after exposure to ScA. ScA rapidly and efficien...

  4. The human papillomavirus (HPV) E6 oncoproteins promotes nuclear localization of active caspase 8

    International Nuclear Information System (INIS)

    The HPV-16 E6 and E6⁎ proteins have been shown previously to be capable of regulating caspase 8 activity. We now show that the capacity of E6 to interact with caspase 8 is common to diverse HPV types, being also seen with HPV-11 E6, HPV-18 E6 and HPV-18 E6⁎. Unlike most E6-interacting partners, caspase 8 does not appear to be a major proteasomal target of E6, but instead E6 appears able to stimulate caspase 8 activation, without affecting the overall apoptotic activity. This would appear to be mediated in part by the ability of the HPV E6 oncoproteins to recruit active caspase 8 to the nucleus. - Highlights: • Multiple HPV E6 oncoproteins interact with the caspase 8 DED domain. • HPV E6 stimulates activation of caspase 8. • HPV E6 promotes nuclear accumulation of caspase 8

  5. The human papillomavirus (HPV) E6 oncoproteins promotes nuclear localization of active caspase 8

    Energy Technology Data Exchange (ETDEWEB)

    Manzo-Merino, Joaquin [Unidad de Investigación Biomédica en Cáncer, Instituto Nacional de Cancerología, México/Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México. Av. San Fernando No. 22, Col. Sección XVI, Tlalpan 14080 (Mexico); Massimi, Paola [International Centre for Genetic Engineering and Biotechnology, Padriciano 99, I-34149 Trieste (Italy); Lizano, Marcela, E-mail: lizanosoberon@gmail.com [Unidad de Investigación Biomédica en Cáncer, Instituto Nacional de Cancerología, México/Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México. Av. San Fernando No. 22, Col. Sección XVI, Tlalpan 14080 (Mexico); Banks, Lawrence, E-mail: banks@icgeb.org [International Centre for Genetic Engineering and Biotechnology, Padriciano 99, I-34149 Trieste (Italy)

    2014-02-15

    The HPV-16 E6 and E6{sup ⁎} proteins have been shown previously to be capable of regulating caspase 8 activity. We now show that the capacity of E6 to interact with caspase 8 is common to diverse HPV types, being also seen with HPV-11 E6, HPV-18 E6 and HPV-18 E6{sup ⁎}. Unlike most E6-interacting partners, caspase 8 does not appear to be a major proteasomal target of E6, but instead E6 appears able to stimulate caspase 8 activation, without affecting the overall apoptotic activity. This would appear to be mediated in part by the ability of the HPV E6 oncoproteins to recruit active caspase 8 to the nucleus. - Highlights: • Multiple HPV E6 oncoproteins interact with the caspase 8 DED domain. • HPV E6 stimulates activation of caspase 8. • HPV E6 promotes nuclear accumulation of caspase 8.

  6. EMT phenotype is induced by increased Src kinase activity via Src-mediated caspase-8 phosphorylation.

    Science.gov (United States)

    Zhao, Yang; Li, XiaoJun; Sun, XiangFei; Zhang, YunFeng; Ren, Hong

    2012-01-01

    Caspase-8 governs multiple cell responses to the microenvironmental cues. However, its integration of "death-life" signalings remains elusive. In our study, the role of caspase-8-Src is well-established as a promoter for migration or metastasis in Casp8(+)Src(+) A549/H226 cells in vivo and in vitro. In particular for nude mice models, mice implanted with Casp8(+)Src(+) A459/H226 cells remarkably increased spontaneous tumor metastatic burden with a significant survival disadvantage. Additionally, we detect that Src-mediated caspase-8 phosphorylation stimulates Src phosphorylation at Tyr-416 via the linkage of Src SH2 domain with phosph-Tyr-380 site of caspase-8. In turn, activated Src can efficiently induce epithelial-mesenchymal transition (EMT) phenotypic features to promote tumor cells metastasis. Surprisingly, RXDLL motif deletion in the DEDa of caspase-8 attenuates tumor cell migration or metastasis via impairing the recruitment of caspase-8 into the cellular periphery where activated Src is subject to caspase-8 phosphorylation. Together, a simple model is that the peripherization of caspase-8 is well-poised to facilitate Src-mediated caspase-8 phosphrylation at Tyr-380, then binding of phospho-Tyr380 of caspase-8 to Src SH2 domain may maintain Src in an active conformation to induce EMT phenotype, a key step toward cancer metastasis. PMID:22508042

  7. GSH-dependent regulation of Fas-mediated caspase-8 activation by acrolein.

    OpenAIRE

    Hristova, Milena; Heuvelmans, Sjanneke; van der Vliet, Albert

    2007-01-01

    Activation of the cysteine protease caspase-8 by the death receptor Fas (CD95/APO-1) in B lymphoblastoid SKW6.4 cells or Jurkat T cells is associated with GSH depletion. Conversely, GSH depletion by the aldehyde acrolein (3–30 μM) was associated with inhibition of Fas-induced caspase-8 activation, although GSH depletion by buthionine sulfoximine (BSO) did not affect caspase-8 activation. In contrast to BSO, acrolein caused a loss of caspase-8 cysteine content in association with direct alkyla...

  8. Novel HTS strategy identifies TRAIL-sensitizing compounds acting specifically through the caspase-8 apoptotic axis.

    Directory of Open Access Journals (Sweden)

    Darren Finlay

    Full Text Available Tumor Necrosis Factor-Related Apoptosis-Inducing Ligand (TRAIL is potentially a very important therapeutic as it shows selectivity for inducing apoptosis in cancer cells whilst normal cells are refractory. TRAIL binding to its cognate receptors, Death Receptors-4 and -5, leads to recruitment of caspase-8 and classical activation of downstream effector caspases, leading to apoptosis. As with many drugs however, TRAIL's usefulness is limited by resistance, either innate or acquired. We describe here the development of a novel 384-well high-throughput screening (HTS strategy for identifying potential TRAIL-sensitizing agents that act solely in a caspase-8 dependent manner. By utilizing a TRAIL resistant cell line lacking caspase-8 (NB7 compared to the same cells reconstituted with the wild-type protein, or with a catalytically inactive point mutant of caspase-8, we are able to identify compounds that act specifically through the caspase-8 axis, rather than through general toxicity. In addition, false positive hits can easily be "weeded out" in this assay due to their activity in cells lacking caspase-8-inducible activity. Screening of the library of pharmacologically active compounds (LOPAC was performed as both proof-of-concept and to discover potential unknown TRAIL sensitizers whose mechanism is caspase-8 mediated. We identified known TRAIL sensitizers from the library and identified new compounds that appear to sensitize specifically through caspase-8. In sum, we demonstrate proof-of-concept and discovery of novel compounds with a screening strategy optimized for the detection of caspase-8 pathway-specific TRAIL sensitizers. This screen was performed in the 384-well format, but could easily be further miniaturized, allows easy identification of artifactual false positives, and is highly scalable to accommodate diverse libraries.

  9. Caspase-8 Binding to Cardiolipin in Giant Unilamellar Vesicles Provides a Functional Docking Platform for Bid

    DEFF Research Database (Denmark)

    Jalmar, Olivier; Franc¸ois-Moutal, Liberty; García-Sáez, Ana-Jesus;

    2013-01-01

    activating platform for caspase-8 at the mitochondrial membrane surface. Destabilisation of this platform alters receptor-mediated apoptosis in diseases such as Barth Syndrome, which is characterised by the presence of immature cardiolipin which does not allow caspase-8 binding. We used a simplified in vitro...... shed light on the active functional role of cardiolipin, bridging the gap between death receptors and mitochondria. © 2013 Jalmar et al....

  10. A synthetic lethal screen identifies FAT1 as an antagonist of caspase-8 in extrinsic apoptosis

    OpenAIRE

    Kranz, Dominique; Boutros, Michael

    2014-01-01

    The extrinsic apoptosis pathway is initiated by binding of death ligands to death receptors resulting in the formation of the death-inducing signaling complex (DISC). Activation of procaspase-8 within the DISC and its release from the signaling complex is required for processing executor caspases and commiting cell death. Here, we report that the atypical cadherin FAT1 interacts with caspase-8 preventing the association of caspase-8 with the DISC. We identified FAT1 in a genome-wide siRNA scr...

  11. When Beauty Is Skin Deep: Regulation of the Wound Response by Caspase-8, RIPK3, and the Inflammasome.

    Science.gov (United States)

    Vince, James E

    2015-08-01

    Caspase-8 downregulation is observed in the epidermis of wounded skin, whereas permanent epidermal caspase-8 deletion causes chronic skin inflammation, suggesting that caspase-8 is a critical regulator of skin homeostasis and, possibly, the wound response. In this issue, Lee et al. document how epidermal caspase-8 deletion, or cutaneous wounding, results in increased NF-κB activation to drive keratinocyte caspase-1 expression and subsequent secretion of the pro-inflammatory cytokines, IL-1β and IL-1α. Consequently, loss of NF-κB activity, caspase-1, or the IL-1 receptor delays wound healing. Previous studies have documented how chronic skin inflammation in caspase-8-deficient mice is rescued by RIPK3 co-deletion. Therefore, targeting caspase-1, IL-1, or RIPK3 itself may benefit treatment of chronic inflammatory skin diseases, or where an inappropriate inflammatory response proves detrimental to wound healing, such as in type 2 diabetes. PMID:26174535

  12. c-FLIP及Caspase-8表达在乳腺癌组织中的表达及临床意义%Expression of c-FLIP and Caspase-8 in Breast Cancer and Their Clinical Significance

    Institute of Scientific and Technical Information of China (English)

    潘峥; 陈军; 覃冠德; 覃思繁

    2012-01-01

    Objective To investigate the expression of c-FLIP and Caspase-8 in breast cancer and their correlation with metastasis and recurrence. Methods Immunohistochemisty was employed to determine the expression of c-FLIP and Caspase-8 in 80 breast carcinomas and paired adjacent breast tissues. Results c-FLIP was overexpressed in breast cancers compared with paired adjacent breast tissues. The expression of c-FLIP was significantly correlated with TNM stages, histological grade, axillary lymph node metastasis, the recurrence of tumor and the express of C-erbB-2. The expression of Caspase-8 was significantly lower in breast cancers compared with paired adjacent breast tissues. The expression of Caspase-8 was significantly correlated with histological grade, tumor size. There was a significantly negative relationship of c-FLIP with Caspase-8. Conclusion The overexpres-sion of c-FLIP and the inactivation of Caspase-8 might enhance the tumour cell proliferation and malignance in breast cancer.%目的 探讨凋亡相关蛋白c-FLIP和Caspase-8在人乳腺癌组织中的表达及相关性,分析其与乳腺癌转移复发的关系.方法 应用免疫组织化学法检测80例乳腺癌组织和相应的癌旁组织中c-FLIP和Caspase-8的表达情况.结果 80例乳腺癌组织中c-FLIP表达的阳性率显著高于相应的癌旁组织(P<0.05),c-FLIP的表达与TNM分期、组织学分级、腋窝淋巴结转移、术后复发及C-erbB-2表达密切相关(P<0.05);Caspase-8表达的阳性率显著低于相应的癌旁组织(P<0.05),Caspase-8的表达与组织学分级、肿瘤大小密切相关(P<0.05).c-FLIP表达和Caspase-8表达有显著负相关性(γ=-0.380,P=0.001).结论 c-FLIP的高表达及Caspase-8表达缺失可能在乳腺癌发生发展中起重要作用.

  13. Voltage dependent anion channel-1 regulates death receptor mediated apoptosis by enabling cleavage of caspase-8

    International Nuclear Information System (INIS)

    Activation of the extrinsic apoptosis pathway by tumour necrosis factor related apoptosis inducing ligand (TRAIL) is a novel therapeutic strategy for treating cancer that is currently under clinical evaluation. Identification of molecular biomarkers of resistance is likely to play an important role in predicting clinical anti tumour activity. The involvement of the mitochondrial type 1 voltage dependent anion channel (VDAC1) in regulating apoptosis has been highly debated. To date, a functional role in regulating the extrinsic apoptosis pathway has not been formally excluded. We carried out stable and transient RNAi knockdowns of VDAC1 in non-small cell lung cancer cells, and stimulated the extrinsic apoptotic pathway principally by incubating cells with the death ligand TRAIL. We used in-vitro apoptotic and cell viability assays, as well as western blot for markers of apoptosis, to demonstrate that TRAIL-induced toxicity is VDAC1 dependant. Confocal microscopy and mitochondrial fractionation were used to determine the importance of mitochondria for caspase-8 activation. Here we show that either stable or transient knockdown of VDAC1 is sufficient to antagonize TRAIL mediated apoptosis in non-small cell lung cancer (NSCLC) cells. Specifically, VDAC1 is required for processing of procaspase-8 to its fully active p18 form at the mitochondria. Loss of VDAC1 does not alter mitochondrial sensitivity to exogenous caspase-8-cleaved BID induced mitochondrial depolarization, even though VDAC1 expression is essential for TRAIL dependent activation of the intrinsic apoptosis pathway. Furthermore, expression of exogenous VDAC1 restores the apoptotic response to TRAIL in cells in which endogenous VDAC1 has been selectively silenced. Expression of VDAC1 is required for full processing and activation of caspase-8 and supports a role for mitochondria in regulating apoptosis signaling via the death receptor pathway

  14. Caspase-8 regulates TNF-α-induced epithelial necroptosis and terminal ileitis.

    Science.gov (United States)

    Günther, Claudia; Martini, Eva; Wittkopf, Nadine; Amann, Kerstin; Weigmann, Benno; Neumann, Helmut; Waldner, Maximilian J; Hedrick, Stephen M; Tenzer, Stefan; Neurath, Markus F; Becker, Christoph

    2011-09-15

    Dysfunction of the intestinal epithelium is believed to result in the excessive translocation of commensal bacteria into the bowel wall that drives chronic mucosal inflammation in Crohn's disease, an incurable inflammatory bowel disease in humans characterized by inflammation of the terminal ileum. In healthy individuals, the intestinal epithelium maintains a physical barrier, established by the tight contact of cells. Moreover, specialized epithelial cells such as Paneth cells and goblet cells provide innate immune defence functions by secreting mucus and antimicrobial peptides, which hamper access and survival of bacteria adjacent to the epithelium. Epithelial cell death is a hallmark of intestinal inflammation and has been discussed as a possible pathogenic mechanism driving Crohn's disease in humans. However, the regulation of epithelial cell death and its role in intestinal homeostasis remain poorly understood. Here we demonstrate a critical role for caspase-8 in regulating necroptosis of intestinal epithelial cells (IECs) and terminal ileitis. Mice with a conditional deletion of caspase-8 in the intestinal epithelium (Casp8(ΔIEC)) spontaneously developed inflammatory lesions in the terminal ileum and were highly susceptible to colitis. Casp8(ΔIEC) mice lacked Paneth cells and showed reduced numbers of goblet cells, indicating dysregulated antimicrobial immune cell functions of the intestinal epithelium. Casp8(ΔIEC) mice showed increased cell death in the Paneth cell area of small intestinal crypts. Epithelial cell death was induced by tumour necrosis factor (TNF)-α, was associated with increased expression of receptor-interacting protein 3 (Rip3; also known as Ripk3) and could be inhibited on blockade of necroptosis. Lastly, we identified high levels of RIP3 in human Paneth cells and increased necroptosis in the terminal ileum of patients with Crohn's disease, suggesting a potential role of necroptosis in the pathogenesis of this disease. Together, our

  15. Allopurinol’s effect on caspase-3 and caspase-8 activity in hypoxic-ischemic newborn rats

    OpenAIRE

    Kenan Özcan; Mehmet Satar; Necmiye Canacankatan; Erdal Taşkın; Kenan Dağlıoğlu

    2013-01-01

    Aim: During reperfusion period of hypoxia-ischemia, cyclooxygenase and xanthine oxidase pathways are induced. A xanthine oxidase inhibitor, allopurinol has been shown to be neuroprotective in hypoxic- ischemic encephalopathy. Caspase-8 and caspase-3 have a key role in neuronal apoptosis. We aimed to test repeated doses of allopurinol’s effect on caspase-3 and caspase-8 activities in newborn rats with hypoxic-ischemic encephalopathy. Material and Method: Seven days old newborn rats were taken ...

  16. The Caspase-8 Homolog Dredd Cleaves Imd and Relish but Is Not Inhibited by p35*

    Science.gov (United States)

    Kim, Chan-Hee; Paik, Donggi; Rus, Florentina; Silverman, Neal

    2014-01-01

    In Drosophila, the Imd pathway is activated by diaminopimelic acid-type peptidoglycan and triggers the humoral innate immune response, including the robust induction of antimicrobial peptide gene expression. Imd and Relish, two essential components of this pathway, are both endoproteolytically cleaved upon immune stimulation. Genetic analyses have shown that these cleavage events are dependent on the caspase-8 like Dredd, suggesting that Imd and Relish are direct substrates of Dredd. Among the seven Drosophila caspases, we find that Dredd uniquely promotes Imd and Relish processing, and purified recombinant Dredd cleaves Imd and Relish in vitro. In addition, interdomain cleavage of Dredd is not required for Imd or Relish processing and is not observed during immune stimulation. Baculovirus p35, a suicide substrate of executioner caspases, is not cleaved by purified Dredd in vitro. Consistent with this biochemistry but contrary to earlier reports, p35 does not interfere with Imd signaling in S2* cells or in vivo. PMID:24891502

  17. Ofloxacin induces apoptosis in microencapsulated juvenile rabbit chondrocytes by caspase-8-dependent mitochondrial pathway

    International Nuclear Information System (INIS)

    Quinolones (QNs)-induced arthropathy is an important toxic effect in immature animals leading to restriction of their therapeutic use in pediatrics. However, the exact mechanism still remains unclear. Recently, we have demonstrated that ofloxacin, a typical QN, induces apoptosis of alginate microencapsulated juvenile rabbit joint chondrocytes by disturbing the β1 integrin functions and inactivating the ERK/MAPK signaling pathway. In this study, we extend our initial observations to further elucidate the mechanism(s) of ofloxacin-induced apoptosis by utilizing specific caspase inhibitors. Pretreatment with both caspase-9-specific inhibitor zLEHD-fmk and caspase-8 inhibitor zIETD-fmk attenuated ofloxacin-induced apoptosis and activation of caspase-3 of chondrocyte in a concentration-dependent manner, as determined by fluorescent dye staining, enzyme activity assay and immunoblotting. Furthermore, the activation of caspase-9, -8 and -3 stimulated by ofloxacin was significantly inhibited in the presence of zIETD-fmk while pretreatment with zLEHD-fmk only blocked the activation of caspase-9 and -3. Ofloxacin also stimulated a concentration-dependent translocation of cytochrome c from mitochondria into the cytosol and a decrease of mitochondrial transmembrane potential, which was completely inhibited by zIETD-fmk. In addition, ofloxacin was found to increase the level of Bax, tBid, p53 in a concentration- and time-dependent manner. Taken together, The current results indicate that the caspase-8-dependent mitochondrial pathway is primarily involved in the ofloxacin-induced apoptosis of microencapsulated juvenile rabbit joint chondrocytes

  18. Allopurinol’s effect on caspase-3 and caspase-8 activity in hypoxic-ischemic newborn rats

    Directory of Open Access Journals (Sweden)

    Kenan Özcan

    2013-03-01

    Full Text Available Aim: During reperfusion period of hypoxia-ischemia, cyclooxygenase and xanthine oxidase pathways are induced. A xanthine oxidase inhibitor, allopurinol has been shown to be neuroprotective in hypoxic- ischemic encephalopathy. Caspase-8 and caspase-3 have a key role in neuronal apoptosis. We aimed to test repeated doses of allopurinol’s effect on caspase-3 and caspase-8 activities in newborn rats with hypoxic-ischemic encephalopathy. Material and Method: Seven days old newborn rats were taken and there were 10 rats in each group. After Ethical Committee was approved (TIBDAM-25, rats were subjected to left carotid artery ligation and hypoxia (8% oxygen and 92% nitrogen for two and half hours. Hypoxic ischemic rats treated with 24 mg/kg allopurinol 30 minutes and 12 hours (AL48 group, and 30 minutes, 12 and 24 hours (AL72 group after hypoxic- ischemic insult. Twenty four hours after last dose, rats were decapitated. The others groups were sham and saline- treated hypoxic- ischemic (H-I group. Caspase- 3 and caspase- 8 activities were measured in both hemispheres.Results: There was no difference in caspase-3 and caspase-8 activities between right and left brain hemispheres in each group (p>0.05. Caspase-3 and caspase-8 activities were significantly lower in sham group when compared to H-I group, AL48 and AL72 groups (all of it, p=0.0001. Even though there were no difference activities of caspase- 3 and caspase- 8 between H-I group and AL48 group (p>0.05, activities of caspase- 3 and caspase- 8 in AL72 group were significantly lower than H-I group and AL48 group (respectively p= 0.0001, p=0.001. Conclusions: Decreased activities of caspase- 3 and caspase- 8 in AL72 group may suggest that totally dosage of 72 mg/kg allopurinol may be effective for reducing neuronal apoptosis in newborn rats with hypoxic- ischemic insult. (Turk Arch Ped 2013; 48: 48-52

  19. Caspase-8 activity is part of the BeWo trophoblast cell defense mechanisms against Trypanosoma cruzi infection.

    Science.gov (United States)

    Carrillo, Ileana; Droguett, Daniel; Castillo, Christian; Liempi, Ana; Muñoz, Lorena; Maya, Juan Diego; Galanti, Norbel; Kemmerling, Ulrike

    2016-09-01

    Congenital Chagas disease is caused by the protozoan parasite Trypanosoma cruzi that must cross the placental barrier during transmission. The trophoblast constitutes the first tissue in contact with the maternal-blood circulating parasite. Importantly, the congenital transmission rates are low, suggesting the presence of local placental defense mechanisms. Cellular proliferation and differentiation as well as apoptotic cell death are induced by the parasite and constitute part of the epithelial turnover of the trophoblast, which has been suggested to be part of those placental defenses. On the other hand, caspase-8 is an essential molecule in the modulation of trophoblast turnover by apoptosis and by epithelial differentiation. As an approach to study whether T. cruzi induced trophoblast turnover and infection is mediated by caspase-8, we infected BeWo cells (a trophoblastic cell line) with the parasite and determined in the infected cells the expression and enzymatic activity of caspase-8, DNA synthesis (as proliferation marker), β-human chorionic gonadotropin (β-hCG) (as differentiation marker) and activity of Caspase-3 (as apoptotic death marker). Parasite load in BeWo cells was measured by DNA quantification using qPCR and cell counting. Our results show that T. cruzi induces caspase-8 activity and that its inhibition increases trophoblast cells infection while decreases parasite induced cellular differentiation and apoptotic cell death, but not cellular proliferation. Thus, caspase-8 activity is part of the BeWo trophoblast cell defense mechanisms against T. cruzi infection. Together with our previous results, we suggest that the trophoblast turnover is part of local placental anti-parasite mechanisms. PMID:27328973

  20. Induction of Caspase 8 by 5-Azacytidine renders NB cells sensitive to TRAIL%5氮杂胞苷诱导NB细胞Caspase 8表达及对TRAIL敏感性的研究

    Institute of Scientific and Technical Information of China (English)

    佟海侠; 张锦华; 张继红; 陆春伟

    2005-01-01

    目的:探讨5氮杂胞苷(5-Azacytidine)对肿瘤坏死因子相关凋亡诱导配体(tumor necrosis factor related apoptosis inducing ligand,TRAIL)诱导神经母细胞瘤(neuroblastoma,NB)细胞株SH-SY5Y凋亡的影响及其发生机制.方法:应用RT-PCR方法检测5氮杂胞苷作用前后SY5Y细胞Caspase 8的表达;应用四甲基偶氮唑蓝(MTT)比色法及流式细胞仪(FCM)检测TRAIL、5氮杂胞苷+TRAIL、5氮杂胞苷+Caspase 8抑制剂+TRAIL对SY5Y细胞生长及凋亡的影响.结果:SY5Y细胞不表达Caspase 8,5氮杂胞苷作用1、3和5d的SY5Y细胞Caspase 8表达逐渐增加;SY5Y细胞对TRAIL不敏感,经5氮杂胞苷诱导表达Caspase 8的 SY5Y 细胞对TRAIL敏感,并呈现一定的时间和剂量依赖性.联合用药组细胞凋亡率分别为(28.6±4.0)%、(38.5±4.2)%和(42.3±6.2)%,与单独用TRAIL组[(9.5±2.0)%、(10.7±1.8)%和(11.2±1.5)%]比较,差异有统计学意义,F值分别为41.131、45.014和49.405,P值均为0.000;Caspase 8抑制剂组细胞凋亡率分别为(11.8±2.0)%、(13.5±2.9)%和(15.1±3.4)%,与相应浓度的5氮杂胞苷+TRAIL组相比,细胞凋亡率明显降低,F值分别为41.131、45.014和49.405,P值均为0.000,说明Caspase 8抑制剂可明显降低TRAIL对表达Caspase 8的SY5Y细胞的杀伤作用.结论:5氮杂胞苷能增强SY5Y细胞对TRAIL的敏感性,其发生机制可能与Caspase 8表达上调有关.

  1. Radiation-Inducible Caspase-8 Gene Therapy for Malignant Brain Tumors

    International Nuclear Information System (INIS)

    Purpose: Patients with malignant gliomas have a poor prognosis. To explore a novel and more effective approach for the treatment of patients with malignant gliomas, we designed a strategy that combines caspase-8 (CSP8) gene therapy and radiation treatment (RT). In addition, the specificity of the combined therapy was investigated to decrease the unpleasant effects experienced by the surrounding normal tissue. Methods and Materials: We constructed the plasmid pEGR-green fluorescence protein that included the radiation-inducible early growth response gene-1 (Egr-1) promoter and evaluated its characteristics. The pEGR-CSP8 was constructed and included the Egr-1 promoter and CSP8 complementary DNA. Assays that evaluated the apoptosis inducibility and cytotoxicity caused by CSP8 gene therapy combined with RT were performed using U251 and U87 glioma cells. The pEGR-CSP8 was transfected into the subcutaneous U251 glioma cells of nude mice by means of in vivo electroporation. The in vivo effects of CSP8 gene therapy combined with RT were evaluated. Results: The Egr-1 promoter yielded a better response with fractionated RT than with single-dose RT. In the assay of apoptosis inducibility and cytotoxicity, pEGR-CSP8 showed response for RT. The pEGR-CSP8 combined with RT is capable of inducing cell death effectively. In mice treated with pEGR-CSP8 and RT, apoptotic cells were detected in pathologic sections, and a significant difference was observed in tumor volumes. Conclusions: Our results indicate that radiation-inducible gene therapy may have great potential because this can be spatially or temporally controlled by exogenous RT and is safe and specific

  2. Inhibition of vacuolar ATPase attenuates the TRAIL-induced activation of caspase-8 and modulates the trafficking of TRAIL receptosomes

    Czech Academy of Sciences Publication Activity Database

    Horová, Vladimíra; Hradilová, Naďa; Jelínková, Iva; Koc, Michal; Švadlenka, Jan; Bražina, Jan; Klíma, Martin; Slavík, J.; Vaculová, Alena; Anděra, Ladislav

    2013-01-01

    Roč. 280, č. 14 (2013), s. 3436-3450. ISSN 1742-464X R&D Projects: GA ČR GAP301/10/1971; GA ČR(CZ) GAP301/11/1730; GA MŠk 1M0506 Institutional support: RVO:68378050 ; RVO:68081707 Keywords : acidification * apoptosis * caspase-8 * TRAIL * V-ATPase Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.986, year: 2013

  3. Molluscan death effector domain (DED)-containing caspase-8 gene from disk abalone (Haliotis discus discus): molecular characterization and expression analysis.

    Science.gov (United States)

    Lee, Youngdeuk; De Zoysa, Mahanama; Whang, Ilson; Lee, Sukkyoung; Kim, Yucheol; Oh, Chulhong; Choi, Cheol Young; Yeo, Sang-Yeob; Lee, Jehee

    2011-02-01

    The caspase family represents aspartate-specific cysteine proteases that play key roles in apoptosis and immune signaling. In this study, we cloned the first death effector domain (DED)-containing molluscan caspase-8 gene from disk abalone (Haliotis discus discus), which is named as hdCaspase-8. The full-length hdCaspase was 2855 bp, with a 1908 bp open reading frame encoding 636 amino acids. The hdCaspase-8 had 72 kDa predicted molecular mass with an estimated isoelectric point (PI) of 6.0. The hdCaspase-8 amino acid sequence contained the characteristic feature of an N-terminal two DED, a C-terminal catalytic domain and the caspase family cysteine active site ⁵¹³KPKLFFLQACQG⁵²⁴. Phylogenetic analysis results showed that hdCaspase-8 is more similar to the invertebrate Tubifex tubifex (sludge worm) caspase-8. Real-time RT-PCR results showed that hdCaspase-8 constitutively and ubiquitously expressed in all tested tissue of unchallenged disk abalone. The basal expression level of hdCaspase-8 in gill tissue was higher than all other tested tissues. The hdCaspase-8 mRNA expression in gill and hemocytes was significantly up-regulated by exposure to bacteria (Vibrio alginolyticus, Vibrio parahemolyticus and Listeria monocytogenes) and VHSV (viral hemorrhagic septicemia virus), as compared to control animals. These results suggest that hdCaspase-8 may be involved in immune response reactions in disk abalone. PMID:21130887

  4. RIP3 Inhibits Inflammatory Hepatocarcinogenesis but Promotes Cholestasis by Controlling Caspase-8- and JNK-Dependent Compensatory Cell Proliferation

    Directory of Open Access Journals (Sweden)

    Mihael Vucur

    2013-08-01

    Full Text Available For years, the term “apoptosis” was used synonymously with programmed cell death. However, it was recently discovered that receptor interacting protein 3 (RIP3-dependent “necroptosis” represents an alternative programmed cell death pathway activated in many inflamed tissues. Here, we show in a genetic model of chronic hepatic inflammation that activation of RIP3 limits immune responses and compensatory proliferation of liver parenchymal cells (LPC by inhibiting Caspase-8-dependent activation of Jun-(N-terminal kinase in LPC and nonparenchymal liver cells. In this way, RIP3 inhibits intrahepatic tumor growth and impedes the Caspase-8-dependent establishment of specific chromosomal aberrations that mediate resistance to tumor-necrosis-factor-induced apoptosis and underlie hepatocarcinogenesis. Moreover, RIP3 promotes the development of jaundice and cholestasis, because its activation suppresses compensatory proliferation of cholangiocytes and hepatic stem cells. These findings demonstrate a function of RIP3 in regulating carcinogenesis and cholestasis. Controlling RIP3 or Caspase-8 might represent a chemopreventive or therapeutic strategy against hepatocellular carcinoma and biliary disease.

  5. Diatom-derived oxylipins induce cell death in sea urchin embryos activating caspase-8 and caspase 3/7.

    Science.gov (United States)

    Ruocco, Nadia; Varrella, Stefano; Romano, Giovanna; Ianora, Adrianna; Bentley, Matt G; Somma, Domenico; Leonardi, Antonio; Mellone, Stefano; Zuppa, Antonio; Costantini, Maria

    2016-07-01

    Diatoms are an important class of unicellular algae that produce bioactive secondary metabolites with cytotoxic activity collectively termed oxylipins, including polyunsaturated aldehydes (PUAs), hydroxyacids (HEPEs), oxo-acids and epoxyalcohols. Previous results showed that at higher concentrations, the PUA decadienal induced apoptosis on copepods and sea urchin embryos via caspase-3 activation; at lower concentrations decadienal affected the expression levels of the caspase-8 gene in embryos of the sea urchin Paracentrotus lividus. In the present work, we studied the effects of other common oxylipins produced by diatoms: two PUAs (heptadienal and octadienal) and four hydroxyacids (5-, 9- 11- and 15-HEPE) on P. lividus cell death and caspase activities. Our results showed that (i) at higher concentrations PUAs and HEPEs induced apoptosis in sea urchin embryos, detected by microscopic observation and through the activation of caspase-3/7 and caspase-8 measured by luminescent assays; (ii) at low concentrations, PUAs and HEPEs affected the expression levels of caspase-8 and caspase-3/7 (isolated for the first time here in P. lividus) genes, detected by Real Time qPCR. These findings have interesting implications from the ecological point of view, given the importance of diatom blooms in nutrient-rich aquatic environments. PMID:27130972

  6. Fatal Hepatitis Mediated by TNFα Requires Caspase-8 and Involves the BH3-only Proteins Bid and Bim

    Science.gov (United States)

    Kaufmann, Thomas; Jost, Philipp J; Pellegrini, Marc; Puthalakath, Hamsa; Gugasyan, Raffi; Gerondakis, Steve; Cretney, Erika; Smyth, Mark J; Silke, John; Hakem, Razq; Bouillet, Philippe; Mak, Tak W; Dixit, Vishva M; Strasser, Andreas

    2009-01-01

    SUMMARY Apoptotic death of hepatocytes, a feature and contributing factor of many chronic and acute liver diseases, can be a consequence of over-activation of the immune system. Injection with lipopolysaccharide (LPS) plus the transcriptional inhibitor D(+)-galactosamine (GalN) or mitogenic T cell activation cause fatal hepatocyte apoptosis in mice. In both settings hepatocyte killing is mediated by TNFα/TNF-R signaling but the effector mechanisms remain unclear. Our analysis of gene-targeted mice showed that caspase-8 is essential for hepatocyte killing in both settings. Loss of Bid, the pro-apoptotic BH3-only protein activated by caspase-8, and essential for Fas ligand-induced hepatocyte killing, resulted only in a minor reduction of liver damage. However, combined loss of Bid and another BH3-only protein, Bim, activated by JNK, protected mice from LPS+GalN-induced hepatitis. These observations identify caspase-8 and the BH3-only proteins Bid and Bim as potential therapeutic targets for treatment of inflammatory liver diseases. PMID:19119023

  7. Dasatinib promotes paclitaxel-induced necroptosis in lung adenocarcinoma with phosphorylated caspase-8 by c-Src.

    Science.gov (United States)

    Diao, Yan; Ma, Xiaobin; Min, WeiLi; Lin, Shuai; Kang, HuaFeng; Dai, ZhiJun; Wang, Xijing; Zhao, Yang

    2016-08-28

    Cisplatin and paclitaxel are considered to be the backbone of chemotherapy in lung adenocarcinoma. These agents show pleiotropic effects on cell death. However, the precise mechanisms remain unclear. The present study reported that phosphorylated caspase-8 at tyrosine 380 (p-Casp8) was characterized as a biomarker of chemoresistance to TP regimen (cisplatin and paclitaxel) in patients with resectable lung adenocarcinoma with significantly poorer 5-year disease-free survival (DFS) and overall survival (OS). Cisplatin killed lung adenocarcinoma cells regardless of c-Src-induced caspase-8 phosphorylation at tyrosine 380. Subsequently, we identified a novel mechanism by which paclitaxel induced necroptosis in lung adenocarcinoma cells that was dependent upon p-Casp8, receptor-interacting protein kinase 1 (RIPK1), and RIPK3. Moreover, dasatinib, a c-Src inhibitor, dephosphorylated caspase-8 to facilitate necroptosis, rather than apoptosis, in paclitaxel-treated p-Casp8-expressing lung adenocarcinoma cells. The data from our study revealed previously unrecognized roles of p-Casp8 as a positive effector in the initiation of necroptosis and as a negative effector in the repression of the interaction between RIPK1 and RIPK3. Moreover, these outcomes supported the need for further clinical studies with the goal of evaluating the efficacy of dasatinib plus paclitaxel in the treatment of lung adenocarcinoma. PMID:27195913

  8. Induction of caspase 8 and reactive oxygen species by ruthenium-derived anticancer compounds with improved water solubility and cytotoxicity.

    Science.gov (United States)

    Vidimar, Vania; Meng, Xiangjun; Klajner, Marcelina; Licona, Cynthia; Fetzer, Ludivine; Harlepp, Sébastien; Hébraud, Pascal; Sidhoum, Marjorie; Sirlin, Claude; Loeffler, Jean-Philippe; Mellitzer, Georg; Sava, Gianni; Pfeffer, Michel; Gaiddon, Christian

    2012-12-01

    Organometallic compounds which contain metals, such as ruthenium or gold, have been investigated as a replacement for platinum-derived anticancer drugs. They often show good antitumor effects, but the identification of their precise mode of action or their pharmacological optimization is still challenging. We have previously described a class of ruthenium(II) compounds with interesting anticancer properties. In comparison to cisplatin, these molecules have lower side effects, a reduced ability to interact with DNA, and they induce cell death in absence of p53 through CHOP/DDIT3. We have now optimized these molecules by improving their cytotoxicity and their water solubility. In this article, we demonstrate that by changing the ligands around the ruthenium we modify the ability of the compounds to interact with DNA. We show that these optimized molecules reduce tumor growth in different mouse models and retain their ability to induce CHOP/DDIT3. However, they are more potent inducers of cancer cell death and trigger the production of reactive oxygen species and the activation of caspase 8. More importantly, we show that blocking reactive oxygen species production or caspase 8 activity reduces significantly the activity of the compounds. Altogether our data suggest that water-soluble ruthenium(II)-derived compounds represent an interesting class of molecules that, depending on their structures, can target several pro-apoptotic signaling pathways leading to reactive oxygen species production and caspase 8 activation. PMID:22964219

  9. 5氮杂胞苷联合干扰素-γ上调神经母细胞瘤细胞Caspase 8表达的研究%5-Azacytidine and IFN-gamma cooperate to upregulate Caspase-8 expression in neuroblastoma cells

    Institute of Scientific and Technical Information of China (English)

    佟海侠; 陆春伟; 王秋实; 王立维

    2011-01-01

    Objective : To investigate if induction of Caspase 8 by demethylation agent 5 - Azacytidine( 5AZA ) and/or γ - interferon ( IFNγ ) renders neuroblastoma ( NB ) cells sensitive to tumor necrosis factor related apoptosis inducing ligand( TRAIL ). Methods: Caspase 8 expression was monitored by Western blot analysis. The effects of 5AZA,IFNγ, TRAIL, 5AZA and/or IFNγ +TRAIL, 5AZA and/or IFNγ + Caspase 8 inhibitor + TRAIL on the growth and apoptosis of NB cells were detected with flow cytometry. The relative Caspase 8 activity was measured with colorimetric assay. Results : Caspase 8 was undetectable in SH - SY5Y( SY5Y ) cells which were resistant to TRAIL , but an increased expression of Caspase 8 was found after treatment with 5AZA and/or IFNγ. The level of Caspase 8 protein in IFNγ +5AZA group was higher than that in single treatment group. Moreover, TRAIL combined with 5AZA and/or IFNγ induced apoptosis in SY5Y cells. The relative Caspase 8 activity of SY5Y cells in SAZA and/or IFNγ + TRAIL group was significantly higher than those of control group, 5AZA group, IFNγ group, TRAIL group and Caspase 8 inhibitor group. Conclusion :5 - AZA and IFNγ could cooperate to upregulate Caspase - 8 expression in NB cells. TRAIL induced apoptosis in NB cells expressing Caspase 8 with an increase of relative Caspase 8 activity.%目的:应用去甲基药5氮杂胞苷(5AZA)和/或干扰素(IFNγ)诱导神经母细胞瘤(neuroblastoma,NB)细胞Caspase 8的表达,并观察是否可以恢复NB细胞对肿瘤坏死因子相关凋亡诱导配体(TRAIL)的敏感性.方法:应用Western blot方法检测5AZA和/或IFNγ作用前后SY5Y细胞Caspase 8蛋白的表达;应用流式细胞术检测5AZA 、IFNγ、TRAIL、5AZA 和/或IFNγ+TRAIL、5AZA和/或IFNγ+Caspase 8抑制剂zIETD-FMK+TRAIL对NB细胞生长及凋亡的影响;应用比色法测定Caspase 8相对活性.结果:对TRAIL耐药的SY5Y细胞不表达Caspase 8,经5AZA 和/或IFNγ处理后Caspase 8 蛋白

  10. Nerve cells apoptosis and Fas and Caspase-8 expression among chronic alcoholic intoxication rats%慢性酒精中毒大鼠神经细胞凋亡及Fas、Caspase8蛋白的表达

    Institute of Scientific and Technical Information of China (English)

    段玉香; 张永利; 王彦

    2012-01-01

    目的 研究慢性酒精中毒大鼠神经细胞凋亡及Fas、Caspase8蛋白表达情况.方法 逐步增加饮水中酒精浓度,建立慢性酒精中毒大鼠动物模型,HE染色光镜下观察大鼠脑组织病理变化,Tunnel法检测大鼠脑细胞凋亡情况,免疫组化法检测Fas、Caspase8蛋白表达情况.结果 酒精组大脑皮质、海马、小脑等部位均有神经细胞数目缺失及细胞变性和损伤,酒精组各脑区凋亡细胞数和Fas、Casepse8蛋白表达阳性细胞数均高于对照组,两组比较差异有统计学意义(P<0.05).结论 慢性酒精中毒大鼠脑存在明显神经细胞凋亡,伴有Fas、Caspase-8蛋白表达增加,提示细胞死亡受体途径在慢性酒精中毒大鼠脑损伤病理过程中发挥作用.%Objective To understand nerve cells apoptosis and Fas and Casepse -8 protein expression status a-mong chronic alcoholic intoxication rats. Method Established chronic alcoholic intoxication rat model by increasing alcohol percentage of drinking gradually. Pathological changes were observed by light microscope, cells apoptosis and Fas and Casepse -8 protein expression were examined by Tunnel and Tmmunohistochemical method. Results In alcohol group, there were nerve cells missing, degeneration and damage in cerebral cortex, seahorse and cerebellum. The cells number of apoptosis and the positive cell of expression Fas and caspase -8 were obviously higher than control group, there was statistical significance between the 2 groups (P < 0.01) . Condusions There were obviously nerve cells apoptosis as well as the expression of Fas and Casepse -8 increased in the rats, which indicated that Fas and Casepse -8 protein attribute to nerve apoptosis and involved in the pathogenesis of chronic alcoholism.

  11. Cleavage by Caspase 8 and Mitochondrial Membrane Association Activate the BH3-only Protein Bid during TRAIL-induced Apoptosis.

    Science.gov (United States)

    Huang, Kai; Zhang, Jingjing; O'Neill, Katelyn L; Gurumurthy, Channabasavaiah B; Quadros, Rolen M; Tu, Yaping; Luo, Xu

    2016-05-27

    The BH3-only protein Bid is known as a critical mediator of the mitochondrial pathway of apoptosis following death receptor activation. However, since full-length Bid possesses potent apoptotic activity, the role of a caspase-mediated Bid cleavage is not established in vivo In addition, due to the fact that multiple caspases cleave Bid at the same site in vitro, the identity of the Bid-cleaving caspase during death receptor signaling remains uncertain. Moreover, as Bid maintains its overall structure following its cleavage by caspase 8, it remains unclear how Bid is activated upon cleavage. Here, Bid-deficient (Bid KO) colon cancer cells were generated by gene editing, and were reconstituted with wild-type or mutants of Bid. While the loss of Bid blocked apoptosis following treatment by TNF-related apoptosis inducing ligand (TRAIL), this blockade was relieved by re-introduction of the wild-type Bid. In contrast, the caspase-resistant mutant Bid(D60E) and a BH3 defective mutant Bid(G94E) failed to restore TRAIL-induced apoptosis. By generating Bid/Bax/Bak-deficient (TKO) cells, we demonstrated that Bid is primarily cleaved by caspase 8, not by effector caspases, to give rise to truncated Bid (tBid) upon TRAIL treatment. Importantly, despite the presence of an intact BH3 domain, a tBid mutant lacking the mitochondrial targeting helices (α6 and α7) showed diminished apoptotic activity. Together, these results for the first time establish that cleavage by caspase 8 and the subsequent association with the outer mitochondrial membrane are two critical events that activate Bid during death receptor-mediated apoptosis. PMID:27053107

  12. B cell receptor cross-linking triggers a caspase-8-dependent apoptotic pathway that is independent of the death effector domain of Fas-associated death domain protein.

    Science.gov (United States)

    Besnault, L; Schrantz, N; Auffredou, M T; Leca, G; Bourgeade, M F; Vazquez, A

    2001-07-15

    We have previously reported that B cell receptors, depending on the degree to which they are cross-linked, can promote apoptosis in various human B cell types. In this study, we show that B cell receptors can trigger two apoptotic pathways according to cross-linking and that these pathways control mitochondrial activation in human Burkitt's lymphoma cells. Whereas soluble anti-mu Ab triggers caspase-independent mitochondrial activation, cross-linked anti-mu Ab induces an apoptotic response associated with a caspase-dependent loss of mitochondrial transmembrane potential. This B cell receptor-mediated caspase-dependent mitochondrial activation is associated with caspase-8 activation. We show here that caspase-8 inhibitors strongly decrease cross-linking-dependent B cell receptor-mediated apoptosis in Burkitt's lymphoma BL41 cells. These inhibitors act upstream from the mitochondria as they prevented the loss of mitochondrial membrane potential observed in B cell receptor-treated BL41 cells. Caspase-8 activation in these cells was also evident from the detection of cleaved fragments of caspase-8 and the cleavage of specific substrates, including Bid. Our data show that cross-linked B cell receptors induced an apoptotic pathway involving sequential caspase-8 activation, loss of mitochondrial membrane potential, and the activation of caspase-9 and caspase-3. Cells expressing a dominant negative mutant of Fas-associated death domain protein were sensitive to cross-linked B cell receptor-induced caspase-8 activation and apoptosis; therefore, this caspase-8 activation was independent of the death effector domain of Fas-associated death domain protein. PMID:11441077

  13. Induction of caspase-8 and death receptors by a new dammarane skeleton from the dried fruits of Forsythia koreana.

    Science.gov (United States)

    Hawas, Usama W; Gamal-Eldeen, Amira M; El-Desouky, Samy K; Kim, Young-Kyoon; Huefner, Antje; Saf, Robert

    2013-01-01

    A new naturally occurring compound based on the dammarane skeleton, i.e. cabralealactone 3-acetate-24-methyl ether, was isolated from the aqueous methanolic extract of Forsythia koreana fruits, along with eight known compounds: cabralealactone 3-acetate, ursolic acid, arctigenin, arctiin, phillyrin, rutin, caffeic acid, and rosmarinic acid. The identification of the isolated compounds was based on their spectral analysis including: HREI-MS, 1D and 2D NMR spectroscopy. The selected compounds and the aqueous methanolic extract were evaluated for their cytotoxic activity against human solid tumour cell lines. Cabralealactone 3-acetate-24-methyl ether and ursolic acid were found to be active against human breast cancer cells (MCF-7). The cytotoxicity was associated with the activation of caspase-8, the induction of the death receptors DR4 and DR5, as well as DNA fragmentation, and was thus due to apoptosis rather than necrosis. PMID:23659170

  14. Compound K, a metabolite of ginseng saponin, induces apoptosis via caspase-8-dependent pathway in HL-60 human leukemia cells

    International Nuclear Information System (INIS)

    Compound K [20-O-β-(D-glucopyranosyl)-20(S)-protopanaxadiol], a metabolite of the protopanaxadiol-type saponins of Panax ginseng C.A. Meyer, has been reported to possess anti-tumor properties to inhibit angiogenesis and to induce tumor apoptosis. In the present study, we investigated the effect of Compound K on apoptosis and explored the underlying mechanisms involved in HL-60 human leukemia cells. We examined the effect of Compound K on the viabilities of various cancer cell lines using MTT assays. DAPI assay, Annexin V and PI double staining, Western blot assay and immunoprecipitation were used to determine the effect of Compound K on the induction of apoptosis. Compound K was found to inhibit the viability of HL-60 cells in a dose- and time-dependent manner with an IC50 of 14 μM. Moreover, this cell death had typical features of apoptosis, that is, DNA fragmentation, DNA ladder formation, and the externalization of Annexin V targeted phosphatidylserine residues in HL-60 cells. In addition, compound-K induced a series of intracellular events associated with both the mitochondrial- and death receptor-dependent apoptotic pathways, namely, (1) the activation of caspases-3, -8, and -9; (2) the loss of mitochondrial membrane potential; (3) the release of cytochrome c and Smac/DIABLO to the cytosol; (4) the translocation of Bid and Bax to mitochondria; and (5) the downregulations of Bcl-2 and Bcl-xL. Furthermore, a caspase-8 inhibitor completely abolished caspase-3 activation, Bid cleavage, and subsequent DNA fragmentation by Compound K. Interestingly, the activation of caspase-3 and -8 and DNA fragmentation were significantly prevented in the presence of cycloheximide, suggesting that Compound K-induced apoptosis is dependent on de novo protein synthesis. The results indicate that caspase-8 plays a key role in Compound K-stimulated apoptosis via the activation of caspase-3 directly or indirectly through Bid cleavage, cytochrome c release, and caspase-9 activation

  15. Mechanism of 2',3'-dimethoxyflavanone-induced apoptosis in breast cancer stem cells: role of ubiquitination of caspase-8 and LC3.

    Science.gov (United States)

    Tran, Thao Anh; Ahn, Kwang Seok; Song, Yeon Woo; Moon, Jeong Yong; Cho, Moonjae; Lim, Yoongho; Cho, Somi Kim

    2014-11-15

    Accumulating evidence has displayed that targeting cancer stem cells (CSCs) is a very promising way for anti-cancer therapies. 2',3'-Dimethoxyflavanone (2',3'-DMF) showed the most potent toxicity of a group of 42 flavonoids tested in MCF-7-SC breast cancer stem cells. 2',3'-DMF triggered intrinsic and extrinsic apoptosis by stimulating the cleavage of PARP and the activation of caspase-9, -8, and -3. Interestingly, 2',3'-DMF induces a dramatic increase in the conversion of LC3, a well-known marker for autophagy. However, acidic vesicular organelles (AVOs), one of the autophagic flux markers were not detected. Co-treatment with chloroquine, the lysosomal inhibitor that blocks autophagic degradation did not show any change in the degree of LC3 conversion, implying that LC3 could play a role in the non-autophagic cell death of MCF-7-SC. We found that 2',3'-DMF induces the ubiquitination of caspase-8, this resulted in an interaction between caspase-8 and LC3, which led to the aggregation and activation of caspase-8. Co-treating cells with 2',3'-DMF and 3-methyladenine, an inhibitor of LC3 lipidation, reduced the activation of caspase-8. These findings provide novel insights into the anti-cancer effects of 2',3'-DMF in breast cancer stem cells by revealing that it induced apoptosis in accompany with the activation of caspase-8 mediated by LC3 conversion. PMID:25132643

  16. Compound K, a metabolite of ginseng saponin, induces apoptosis via caspase-8-dependent pathway in HL-60 human leukemia cells

    Directory of Open Access Journals (Sweden)

    Choi Jung-Hye

    2009-12-01

    Full Text Available Abstract Background Compound K [20-O-β-(D-glucopyranosyl-20(S-protopanaxadiol], a metabolite of the protopanaxadiol-type saponins of Panax ginseng C.A. Meyer, has been reported to possess anti-tumor properties to inhibit angiogenesis and to induce tumor apoptosis. In the present study, we investigated the effect of Compound K on apoptosis and explored the underlying mechanisms involved in HL-60 human leukemia cells. Methods We examined the effect of Compound K on the viabilities of various cancer cell lines using MTT assays. DAPI assay, Annexin V and PI double staining, Western blot assay and immunoprecipitation were used to determine the effect of Compound K on the induction of apoptosis. Results Compound K was found to inhibit the viability of HL-60 cells in a dose- and time-dependent manner with an IC50 of 14 μM. Moreover, this cell death had typical features of apoptosis, that is, DNA fragmentation, DNA ladder formation, and the externalization of Annexin V targeted phosphatidylserine residues in HL-60 cells. In addition, compound-K induced a series of intracellular events associated with both the mitochondrial- and death receptor-dependent apoptotic pathways, namely, (1 the activation of caspases-3, -8, and -9; (2 the loss of mitochondrial membrane potential; (3 the release of cytochrome c and Smac/DIABLO to the cytosol; (4 the translocation of Bid and Bax to mitochondria; and (5 the downregulations of Bcl-2 and Bcl-xL. Furthermore, a caspase-8 inhibitor completely abolished caspase-3 activation, Bid cleavage, and subsequent DNA fragmentation by Compound K. Interestingly, the activation of caspase-3 and -8 and DNA fragmentation were significantly prevented in the presence of cycloheximide, suggesting that Compound K-induced apoptosis is dependent on de novo protein synthesis. Conclusions The results indicate that caspase-8 plays a key role in Compound K-stimulated apoptosis via the activation of caspase-3 directly or indirectly through

  17. Intrinsic caspase-8 activation mediates sensitization of erlotinib-resistant tumor cells to erlotinib/cell-cycle inhibitors combination treatment

    Science.gov (United States)

    Orzáez, M; Guevara, T; Sancho, M; Pérez-Payá, E

    2012-01-01

    Inhibitors of the tyrosine kinase activity of epidermal growth factor receptor, as erlotinib, have an established role in treating several cancer types. However, resistance to erlotinib, particularly in breast cancer cell lines, and erlotinib treatment-associated disorders have also been described. Also, methods and combination therapies that could reverse resistance and ameliorate non-desirable effects represent a clinical challenge. Here, we show that the ATP non-competitive CDK2/cyclin A inhibitor NBI1 sensitizes erlotinib-resistant tumor cells to the combination treatment (co-treatment) for apoptosis-mediated cell death. Furthermore, in erlotinib-sensitive cells, the effective dose of erlotinib was lower in the presence of NBI1. The analysis in the breast cancer MDA-MB-468 erlotinib-resistant and in lung cancer A549 cell lines of the molecular mechanism underlying the apoptosis induced by co-treatment highlighted that the accumulation of DNA defects and depletion of cIAP and XIAP activates the ripoptosome that ultimately activates caspases-8 and -10 and apoptosis. This finding could have significant implications for future treatment strategies in clinical settings. PMID:23096116

  18. Smac Mimetic Bypasses Apoptosis Resistance in FADD- or Caspase-8-Deficient Cells by Priming for Tumor Necrosis Factor α-Induced Necroptosis

    Directory of Open Access Journals (Sweden)

    Bram Laukens

    2011-10-01

    Full Text Available Searching for new strategies to bypass apoptosis resistance, we investigated the potential of the Smac mimetic BV6 in Jurkat leukemia cells deficient in key molecules of the death receptor pathway. Here, we demonstrate for the first time that Smac mimetic primes apoptosis-resistant, FADD- or caspase-8-deficient leukemia cells for TNFα-induced necroptosis in a synergistic manner. In contrast to TNFα, Smac mimetic significantly enhances CD95-induced apoptosis in wild-type but not in FADD-deficient cells. Interestingly, Smac mimetic- and TNFα-mediated cell death occurs without characteristic features of apoptosis (i.e., caspase activation, DNA fragmentation in FADD-deficient cells. By comparison, Smac mimetic and TNFα trigger activation of caspase-8, -9, and -3 and DNA fragmentation in wild-type cells. Consistently, the caspase inhibitor zVAD.fmk fails to block Smac mimetic- and TNFα-triggered cell death in FADD- or caspase-8-deficient cells, while it confers protection in wild-type cells. By comparison, necrostatin-1, an RIP1 kinase inhibitor, abolishes Smac mimetic- and TNFα-induced cell death in FADD- or caspase-8-deficient. Thus, Smac mimetic enhances TNFα-induced cell death in leukemia cells via two distinct pathways in a context-dependent manner: it primes apoptosis-resistant cells lacking FADD or caspase-8 to TNFα-induced, RIP1-dependent and caspase-independent necroptosis, whereas it sensitizes apoptosis-proficient cells to TNFα-mediated, caspase-dependent apoptosis. These findings have important implications for the therapeutic exploitation of necroptosis as an alternative cell death program to overcome apoptosis resistance.

  19. A ginseng saponin metabolite-induced apoptosis in HepG2 cells involves a mitochondria-mediated pathway and its downstream caspase-8 activation and Bid cleavage

    International Nuclear Information System (INIS)

    20-O-(β-D-Glucopyranosyl)-20(S)-protopanaxadiol (IH901), an intestinal bacterial metabolite of ginseng saponin formed from ginsenosides Rb1, Rb2, and Rc, is suggested to be a potential chemopreventive agent. Here, we show that IH901 induces apoptosis in human hepatoblastoma HepG2 cells. IH901 led to an early activation of procaspase-3 (12 h posttreatment), and the activation of caspase-8 became evident only later (18 h posttreatment). Caspase activation was a necessary requirement for apoptosis because caspase inhibitors significantly inhibited cell death by IH901. Treatment of HepG2 cells with IH901 also induced the cleavage of cytosolic factors such as Bid and Bax and translocation of truncated Bid (tBid) to mitochondria. A time-dependent release of cytochrome c from mitochondria was observed, which was accompanied by activation of caspase-9. A broad-spectrum caspase inhibitor, N-benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone (zVAD-fmk), and a specific inhibitor for caspase-8, N-benzyloxycarbonyl-Ile-Glu-Thr-Asp-fluoromethylketone (zIETD-fmk), abrogated Bid processing and translocation, and caspase-3 activation. Cytochrome c release was inhibited by zVAD-fmk, however, the inhibition by zIETD-fmk was not complete. The activation of caspase-8 was inhibited not only by zIETD-fmk but also by zVAD-fmk. The results, together with the kinetic change of caspase activation, indicate that activation of caspase-8 occurred downstream of caspase-3 and -9. Our data suggest that the activation of caspase-8 after early caspase-3 activation might act as an amplification loop necessary for successful apoptosis. Primary hepatocytes isolated from normal Sprague-Dawley rats were not affected by IH901 (0-60 μM). The very low toxicity in normal hepatocytes and high activity in hepatoblastoma HepG2 cells suggest that IH901 is a promising experimental cancer chemopreventive agent

  20. Caspase 8 and maspin are downregulated in breast cancer cells due to CpG site promoter methylation

    International Nuclear Information System (INIS)

    Epigenetic changes associated with promoter DNA methylation results in silencing of several tumor suppressor genes that lead to increased risk for tumor formation and for progression of the cancer. Methylation specific PCR (MSP) and bisulfite sequencing were used for determination of proapoptotic gene Caspase 8 (CASP8) and the tumor suppressor gene maspin promoter methylation in four breast cancer and two non-tumorigenic breast cell lines. Involvement of histone H3 methylation in those cell lines were examined by CHIP assay. The CpG sites in the promoter region of CASP8 and maspin were methylated in all four breast cancer cell lines but not in two non-tumorigenic breast cell lines. Demethylation agent 5-aza-2'-deoxycytidine (5-aza-dc) selectively inhibits DNA methyltransferases, DNMT3a and DNMT3b, and restored CASP8 and maspin gene expression in breast cancer cells. 5-aza-dc also reduced histone H3k9me2 occupancy on CASP8 promoter in SKBR3cells, but not in MCF-7 cells. Combination of histone deacetylase inhibitor Trichostatin A (TSA) and 5-aza-dc significant decrease in nuclear expression of Di-methyl histone H3-Lys27 and slight increase in acetyl histone H3-Lys9 in MCF-7 cells. CASP8 mRNA and protein level in MCF-7 cells were increased by the 5-aza-dc in combination with TSA. Data from our study also demonstrated that treatment with 5-FU caused a significant increase in unmethylated CASP8 and in CASP8 mRNA in all 3 cancer lines. CASP8 and maspin expression were reduced in breast cancer cells due to promoter methylation. Selective application of demethylating agents could offer novel therapeutic opportunities in breast cancer

  1. Influence of 5-Azacytidine on Drug Resistance of Caspase-8 Silence Neuroblastoma%去甲基药5-氮杂胞苷对Caspase-8缺乏的神经母细胞瘤细胞化疗敏感性的影响

    Institute of Scientific and Technical Information of China (English)

    周广玉; 李爱敏; 初清; 王晓莉

    2010-01-01

    目的 探讨去甲基5-氮杂胞苷能否恢复神经母细胞瘤(NB)细胞中Caspase-8的表达水平,从而提高NB细胞SY5Y对常用化疗药物依托泊苷的敏感性.方法 采用反转录-PCR(RT-PCR)技术检测5-氮杂胞苷作用前后Caspase-8 mRNA的表达.Elivision二步法检测5-氮杂胞苷作用前后SY5Y细胞中Caspase-8蛋白的表达.应用四甲基偶氮唑蓝(MTT)法检测Caspase-8缺乏的NB细胞中加入化疗依托泊苷后细胞存活率,比较加入5-氮杂咆苷后再入依托泊苷后细胞存活率的变化.结果 RT-PCR方法未检测到SY5Y细胞中Caspase-8 mRNA表达,5-氮杂胞苷单独作用3d可以检测到Caspase-8 mRNA表达,5d组Caspase-8 mRNA表达较3d组明显增强,且Caspase-8 mRNA表达水平随5-氮杂胞苷水平增高而增高.Elivision二步法检测SY5Y细胞中Caspase-8蛋白表达阴性,5-氮杂胞苷作用3d后Caspase-8蛋白表达呈阳性.MTT法检测发现小同质量浓度的依托泊苷(0.1、0.3、1.0、2.5)mg·L-1单独作用24h组细胞存活率分别为94.16%±5.89%、76.46%±5.83%、44.31%±5 05%、36.15%±5.71%;5-氮杂胞苷+同质量浓度依托泊苷组细胞存活率分别为84.23%±6 95%,61.00%±4.98%,31.64%±3.84%,23.75%±1.89%,联合作用组细胞存活率较单独作用组细胞存活率明显下降,其差异均有统计学意义(Pa<0.01).结论 SY5Y细胞不表达Caspase-8 mRNA及蛋白,5-氮杂胞苷可诱导SY5Y细胞Caspase-8 mRNA及蛋白表达,且随时间延长,Caspase-8 mRNA表达随之增加.依托泊苷对NB细胞SY5Y具有增殖抑制作用.5-氮杂胞苷可增强其对SY5Y的增殖抑制作用,并提高化疗的敏感性.

  2. Unusual roles of caspase-8 in triple-negative breast cancer cell line MDA-MB-231.

    Science.gov (United States)

    De Blasio, Anna; Di Fiore, Riccardo; Morreale, Marco; Carlisi, Daniela; Drago-Ferrante, Rosa; Montalbano, Mauro; Scerri, Christian; Tesoriere, Giovanni; Vento, Renza

    2016-06-01

    Triple-negative breast cancer (TNBC) is a clinically aggressive form of breast cancer that is unresponsive to endocrine agents or trastuzumab. TNBC accounts for ~10-20% of all breast cancer cases and represents the form with the poorest prognosis. Patients with TNBC are at higher risk of early recurrence, mainly in the lungs, brain and soft tissue, therefore, there is an urgent need for new therapies. The present study was carried out in MDA-MB-231 cells, where we assessed the role of caspase-8 (casp-8), a critical effector of death receptors, also involved in non‑apoptotic functions. Analysis of casp-8 mRNA and protein levels indicated that they were up-regulated with respect to the normal human mammalian epithelial cells. We demonstrated that silencing of casp-8 by small interfering-RNA, strongly decreased MDA-MB-231 cell growth by delaying G0/G1- to S-phase transition and increasing p21, p27 and hypo-phosphorylated/active form of pRb levels. Surprisingly, casp-8-knockdown, also potently increased both the migratory and metastatic capacity of MDA-MB‑231 cells, as shown by both wound healing and Matrigel assay, and by the expression of a number of related-genes and/or proteins such as VEGFA, C-MYC, CTNNB1, HMGA2, CXCR4, KLF4, VERSICAN V1 and MMP2. Among these, KLF4, a transcriptional factor with a dual role (activator and repressor), seemed to play critical roles. We suggest that in MDA-MB‑231 cells, the endogenous expression of casp-8 might keep the cells perpetually cycling through downregulation of KLF4, the subsequent lowering of p21 and p27, and the inactivation by hyperphosphorylation of pRb. Simultaneously, by lowering the expression of some migratory and invasive genes, casp-8 might restrain the metastatic ability of the cells. Overall, our findings showed that, in MDA-MB-231 cells, casp-8 might play some unusual roles which should be better explored, in order to understand whether it might be identified as a molecular therapeutic target. PMID

  3. Harmol induces apoptosis by caspase-8 activation independently of Fas/Fas ligand interaction in human lung carcinoma H596 cells.

    Science.gov (United States)

    Abe, Akihisa; Yamada, Hiroyuki

    2009-06-01

    The beta-carboline alkaloids are naturally existing plant substances. It is known that these alkaloids have a wide spectrum of neuropharmacological, psychopharmacological, and antitumor effects. Therefore, they have been traditionally used in oriental medicine for the treatment of various diseases including cancers and malaria. In this study, harmol and harmalol, which are beta-carboline alkaloids, were examined for their antitumor effect on human lung carcinoma cell lines, and structure-activity relationship was also investigated. H596, H226, and A549 cells were treated with harmol and harmalol, respectively. Apoptosis was induced by harmol only in H596 cells. In contrast, harmalol had negligible cytotoxicity in three cell lines. Harmol induced caspase-3, caspase-8, and caspase-9 activities and caspase-3 activities accompanied by cleavage of poly-(ADP-ribose)-polymerase. Furthermore, harmol treatment decreased the native Bid protein, and induced the release of cytochrome c from mitochondria to cytosol. The apoptosis induced by harmol was completely inhibited by caspase-8 inhibitor and partially inhibited by caspase-9 inhibitor. The antagonistic antibody ZB4 blocked Fas ligand-induced apoptosis, but had no effect on harmol-induced apoptosis. Harmol had no significant effect on the expression of Fas. In conclusion, our results showed that the harmol could cause apoptosis-inducing effects in human lung H596 cells through caspase-8-dependent pathway but independent of Fas/Fas ligand interaction. PMID:19318910

  4. Docosahexaenoic acid induces apoptosis in MCF-7 cells in vitro and in vivo via reactive oxygen species formation and caspase 8 activation.

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    Ki Sung Kang

    Full Text Available BACKGROUND: The present study sought to further investigate the in vitro and in vivo anticancer effects of a representative omega-3 fatty acid, docosahexaenoic acid (DHA, with a focus on assessing the induction of oxidative stress and apoptosis as an important mechanism for its anticancer actions. METHODOLOGY/PRINCIPAL FINDINGS: In vitro studies showed that DHA strongly reduces the viability and DNA synthesis of MCF-7 human breast cancer cells in culture, and also promotes cell death via apoptosis. Mechanistically, accumulation of reactive oxygen species and activation of caspase 8 contribute critically to the induction of apoptotic cell death. Co-presence of antioxidants or selective inhibition or knockdown of caspase 8 each effectively abrogates the cytotoxic effect of DHA. Using athymic nude mice as an in vivo model, we found that feeding animals the 5% fish oil-supplemented diet for 6 weeks significantly reduces the growth of MCF-7 human breast cancer cells in vivo through inhibition of cancer cell proliferation as well as promotion of cell death. Using 3-nitrotyrosine as a parameter, we confirmed that the fish oil-supplemented diet significantly increases oxidative stress in tumor cells in vivo. Analysis of fatty acid content in plasma and tissues showed that feeding animals a 5% fish oil diet increases the levels of DHA and eicosapentaenoic acid in both normal and tumorous mammary tissues by 329% and 300%, respectively. CONCLUSIONS/SIGNIFICANCE: DHA can strongly induce apoptosis in human MCF-7 breast cancer cells both in vitro and in vivo. The induction of apoptosis in these cells is selectively mediated via caspase 8 activation. These observations call for further studies to assess the effectiveness of fish oil as a dietary supplement in the prevention and treatment of human breast cancer.

  5. Host cell killing by the West Nile Virus NS2B-NS3 proteolytic complex: NS3 alone is sufficient to recruit caspase-8-based apoptotic pathway

    International Nuclear Information System (INIS)

    The West Nile Virus (WNV) non-structural proteins 2B and 3 (NS2B-NS3) constitute the proteolytic complex that mediates the cleavage and processing of the viral polyprotein. NS3 recruits NS2B and NS5 proteins to direct protease and replication activities. In an effort to investigate the biology of the viral protease, we cloned cDNA encoding the NS2B-NS3 proteolytic complex from brain tissue of a WNV-infected dead crow, collected from the Lower Merion area (Merion strain). Expression of the NS2B-NS3 gene cassette induced apoptosis within 48 h of transfection. Electron microscopic analysis of NS2B-NS3-transfected cells revealed ultra-structural changes that are typical of apoptotic cells including membrane blebbing, nuclear disintegration and cytoplasmic vacuolations. The role of NS3 or NS2B in contributing to host cell apoptosis was examined. NS3 alone triggers the apoptotic pathways involving caspases-8 and -3. Experimental results from the use of caspase-specific inhibitors and caspase-8 siRNA demonstrated that the activation of caspase-8 was essential to initiate apoptotic signaling in NS3-expressing cells. Downstream of caspase-3 activation, we observed nuclear membrane ruptures and cleavage of the DNA-repair enzyme, PARP in NS3-expressing cells. Nuclear herniations due to NS3 expression were absent in the cells treated with a caspase-3 inhibitor. Expression of protease and helicase domains themselves was sufficient to trigger apoptosis generating insight into the apoptotic pathways triggered by NS3 from WNV

  6. TNF-alpha-induced mitochondrial alterations in human T cells requires FADD and caspase-8 activation but not RIP and caspase-3 activation.

    Science.gov (United States)

    Shakibaei, Mehdi; Sung, Bokyung; Sethi, Gautam; Aggarwal, Bharat B

    2010-09-15

    Although much is known about how TNF-alpha induces apoptosis in the presence of inhibitors of protein synthesis, little is known about how it induces apoptosis without these inhibitors. In this report we investigated temporal sequence of events induced by TNF-alpha in the absence of protein synthesis. Regardless of whether we measured the effects by plasma membrane phosphotidylserine accumulation, by DNA strand breaks, or activation of caspases, significant changes were observed only between 12-24 h of TNF-alpha treatment. One of the earliest changes observed after TNF-alpha treatment was mitochondrial swelling at 10 min; followed by cytochrome c and Smac release at 10-30 min, and then heterochromatin clumping occurred at 60 min. While genetic deletion of receptor-interaction protein (RIP) had no effect on TNF-alpha-induced mitochondrial damage, deletion of Fas-associated death domain (FADD) abolished the TNF-induced mitochondrial swelling. Since pan-caspase inhibitor z-VAD-fmk abolished the TNF-alpha-induced mitochondrial changes, z-DEVD-fmk, an inhibitor of caspase-3 had no effect, suggesting that TNF-alpha-induced mitochondrial changes or cytochrome c and Smac release requires caspase-8 but not caspase-3 activation. Overall, our results indicated that mitochondrial changes are early events in TNF-alpha-induced apoptosis and that these mitochondrial changes require recruitment of FADD and caspase-8 activation, but not caspase-3 activation or RIP recruitment. PMID:20136500

  7. Mycobacterium tuberculosis-infected human monocytes down-regulate microglial MMP-2 secretion in CNS tuberculosis via TNFα, NFκB, p38 and caspase 8 dependent pathways

    Directory of Open Access Journals (Sweden)

    Elkington Paul T

    2011-05-01

    Full Text Available Abstract Tuberculosis (TB of the central nervous system (CNS is a deadly disease characterized by extensive tissue destruction, driven by molecules such as Matrix Metalloproteinase-2 (MMP-2 which targets CNS-specific substrates. In a simplified cellular model of CNS TB, we demonstrated that conditioned medium from Mycobacterium tuberculosis-infected primary human monocytes (CoMTb, but not direct infection, unexpectedly down-regulates constitutive microglial MMP-2 gene expression and secretion by 72.8% at 24 hours, sustained up to 96 hours (P M.tb-infected monocyte-dependent networks paradoxically involves the pro-inflammatory mediators TNF-α, p38 MAP kinase and NFκB in addition to a novel caspase 8-dependent pathway.

  8. Prostaglandin F2alpha- and FAS-activating antibody-induced regression of the corpus luteum involves caspase-8 and is defective in caspase-3 deficient mice

    Directory of Open Access Journals (Sweden)

    Flavell Richard A

    2003-02-01

    Full Text Available Abstract We recently demonstrated that caspase-3 is important for apoptosis during spontaneous involution of the corpus luteum (CL. These studies tested if prostaglandin F2α (PGF2α or FAS regulated luteal regression, utilize a caspase-3 dependent pathway to execute luteal cell apoptosis, and if the two receptors work via independent or potentially shared intracellular signaling components/pathways to activate caspase-3. Wild-type (WT or caspase-3 deficient female mice, 25–26 days old, were given 10 IU equine chorionic gonadotropin (eCG intraperitoneally (IP followed by 10 IU human chorionic gonadotropin (hCG IP 46 h later to synchronize ovulation. The animals were then injected with IgG (2 micrograms, i.v., the FAS-activating antibody Jo2 (2 micrograms, i.v., or PGF2α (10 micrograms, i.p. at 24 or 48 h post-ovulation. Ovaries from each group were collected 8 h later for assessment of active caspase-3 enzyme and apoptosis (measured by the TUNEL assay in the CL. Regardless of genotype or treatment, CL in ovaries collected from mice injected 24 h after ovulation showed no evidence of active caspase-3 or apoptosis. However, PGF2α or Jo2 at 48 h post-ovulation and collected 8 h later induced caspase-3 activation in 13.2 ± 1.8% and 13.7 ± 2.2 % of the cells, respectively and resulted in 16.35 ± 0.7% (PGF2α and 14.3 ± 2.5% TUNEL-positive cells when compared to 1.48 ± 0.8% of cells CL in IgG treated controls. In contrast, CL in ovaries collected from caspase-3 deficient mice whether treated with PGF2α , Jo2, or control IgG at 48 h post-ovulation showed little evidence of active caspase-3 or apoptosis. CL of WT mice treated with Jo2 at 48 h post-ovulation had an 8-fold increase in the activity of caspase-8, an activator of caspase-3 that is coupled to the FAS death receptor. Somewhat unexpectedly, however, treatment of WT mice with PGF2α at 48 h post-ovulation resulted in a 22-fold increase in caspase-8 activity in the CL, despite the fact

  9. Autoregulatory Feedback Mechanism of P38MAPK/Caspase-8 in Photodynamic Therapy-Hydrophilic/Lipophilic Tetra-α-(4-carboxyphenoxy Phthalocyanine Zinc-Induced Apoptosis of Human Hepatocellular Carcinoma Bel-7402 Cells

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    Yu Wang

    2014-01-01

    Full Text Available Photodynamic therapy (PDT is a novel and promising antitumor treatment. Our previous study showed that hydrophilic/lipophilic tetra-α-(4-carboxyphenoxy phthalocyanine zinc- (TαPcZn- mediated PDT (TαPcZn-PDT inhibits the proliferation of human hepatocellular carcinoma Bel-7402 cells by triggering apoptosis and arresting cell cycle. However, mechanisms of TαPcZn-PDT-induced apoptosis of Bel-7402 cells have not been fully clarified. In the present study, therefore, effect of TαPcZn-PDT on apoptosis, P38MAPK, p-P38MAPK, Caspase-8, Caspase-3, Bcl-2, Bid, Cytochrome c, and mitochondria membrane potential in Bel-7402 cells without or with P38MAPK inhibitor SB203580 or Caspase-8 inhibitor Ac-IEFD-CHO was investigated by haematoxylin and eosin (HE staining assay, flow cytometry analysis of annexin V-FITC/propidium iodide (PI double staining cells and 5,5′,6,6′-tetrachloro-1,1′,3,3′-tetraethylbenzimidazolylcarbocyanine iodide (JC-1, and immunoblot assay. We found that TαPcZn-PDT resulted in apoptosis induction, activation of P38MAPK, Caspase-8, Caspase-3, and Bid, downregulation of Bcl-2, release of Cytochrome c from mitochondria, and disruption of mitochondrial membrane potential in TαPcZn-PDT-treated Bel-7402 cells. In contrast, SB203580 or Ac-IEFD-CHO attenuated induction of apoptosis, activation of P38MAPK, Caspase-8, Caspase-3, and Bid, downregulation of Bcl-2, release of Cytochrome c from mitochondria, and disruption of mitochondrial membrane potential in TαPcZn-PDT-treated Bel-7402 cells. Taken together, we conclude that Caspase-3, Bcl-2, Bid, and mitochondria are involved in autoregulatory feedback of P38MAPK/Caspase-8 during TαPcZn-PDT-induced apoptosis of Bel-7402 cells.

  10. Memantine prevents cognitive impairment and reduces Bcl-2 and caspase 8 immunoreactivity in rats injected with amyloid β1-40.

    Science.gov (United States)

    Miguel-Hidalgo, José Javier; Paul, Ian A; Wanzo, Valerie; Banerjee, Pradeep K

    2012-10-01

    Amyloid-beta peptides (Aβ) can trigger apoptotic cascades in neurons. We found previously that memantine, an uncompetitive antagonist of N-methyl-D-aspartate (NMDA) receptors approved for the treatment of moderate to severe Alzheimer's disease, can prevent neurodegeneration induced by intracranial Aβ(1-40) injection. In this study, we tested the hypothesis that memantine prevents Aβ(1-40)-mediated cognitive impairment, neurodegeneration, and apoptosis of hippocampal neurons in rats. In addition, we hypothesized that Aβ(1-40) injection would induce changes in the levels of one or more apoptosis-related proteins, and that these changes would be attenuated by memantine treatment. Female Sprague-Dawley rats were administered memantine (continuous subcutaneous application, 9.6-14.4mg/kg/day; n=8) or vehicle (water; n=8) for 9 days. Two days after treatment initiation, the animals were bilaterally injected with Aβ(1-40) into the CA1/DG region of the hippocampus, subjected to active avoidance testing for 7 days, and sacrificed for immunohistochemical examination of four caspases (3, 6, 8, and 9) and three proteins of the Bcl-2 family (Bcl-2, Bax, and Bad). Injection of Aβ resulted in neurodegeneration, DNA fragmentation, increased Bcl-2 immunostaining, and significantly impaired performance in an active avoidance task, all which were significantly attenuated in rats treated with memantine. No differences in immunoreactivity of caspases 3, 6, 8, and 9 were discovered between groups after 7 days. Additional experiments demonstrated that an increase in caspase 8 immunostaining, observed 3 days after Aβ(1-40) injection, was significantly attenuated in memantine-treated rats. These data suggest that, in rats, memantine can prevent amyloid-triggered expression of apoptosis-related markers and concomitant cognitive deficits. PMID:22824463

  11. Alterations in blood pressure, antioxidant status and caspase 8 expression in cobalt chloride-induced cardio-renal dysfunction are reversed by Ocimum gratissimum and gallic acid in Wistar rats.

    Science.gov (United States)

    Akinrinde, A S; Oyagbemi, A A; Omobowale, T O; Asenuga, E R; Ajibade, T O

    2016-07-01

    The protective abilities of the chloroform extract of Ocimum gratissimum (COG) and gallic acid against cobalt chloride (CoCl2) - induced cardiac and renal toxicity were evaluated. Rats were exposed to CoCl2 (350ppm) for 7 days, either alone, or in combination with COG (100 and 200mg/kg) or gallic acid (120mg/kg). CoCl2 given alone, caused significant increases (pGST) and catalase (CAT). CoCl2 also produced significant reduction (p<0.05) in systolic (SBP), diastolic (DBP) and mean arterial (MAP) blood pressures. Oral COG and gallic acid treatment significantly reduced (p<0.05) the levels of H2O2 and MDA; with reduced expression of caspase 8 and restoration of GSH levels, GPx, SOD and CAT activities, howbeit, to varying degrees in the heart and kidneys. COG (200mg/kg) was most effective in restoring the blood pressures in the rats to near control levels. CoCl2-induced histopathological lesions including myocardial infarction and inflammation and renal tubular necrosis and inflammation were effectively ameliorated by the treatments administered. This study provides evidence for the protective roles of O. gratissimum and gallic acid by modulation of CoCl2-induced alterations in blood pressure, antioxidant status and pro-apoptotic caspase 8 in Wistar rats. PMID:27259349

  12. Synergistic Effect of Subtoxic-dose Cisplatin and TRAIL to Mediate Apoptosis by Down-regulating Decoy Receptor 2 and Up-regulating Caspase-8, Caspase-9 and Bax Expression on NCI-H460 and A549 Cells

    Directory of Open Access Journals (Sweden)

    Xiaoyan Zhang

    2013-05-01

    Full Text Available Objective(s: Although tumor necrosis factor-related apoptosis-inducing ligand (TRAIL can selectively induce apoptosis in tumor cells, more than half of tumors including non-small cell lung cancer (NSCLC exhibit TRAIL-resistance. The purpose of this study was to determine whether subtoxic-dose cisplatin and TRAIL could synergistically enhance apoptosis on NSCLC cells and investigate its underlying mechanisms. Materials and Methods:NCI-H460 and A549 cells were treated with TRAIL alone, cisplatin alone or combination treatment in this study. The cytotoxicity was evaluated according to Sulforhodamine B assay, and apoptosis was examined using Hoechst 33342 staining and flow cytometry. The mRNA and protein levels of TRAIL receptors and apoptotic proteins including caspase-8, caspase-9, Bcl-2 and Bax were determined by RT-PCR and Western blotting, respectively. Results:Our results showed that NCI-H460 cells were sensitive to TRAIL, whereas A549 cells were resistant. However, subtoxic-dose cisplatin could enhance the both cells to TRAIL-mediated cell proliferation inhibition and apoptosis. The underlying mechanisms might be associated with the down-regulation of DcR2 and up-regulation of Caspase-8, Caspase-9 and Bax. Conclusion:Subtoxic-dose cisplatin could enhance both TRAIL- sensitive and TRAIL- resistant NSCLC cells to TRAIL-mediated apoptosis. These findings motivated further studies to evaluate such a combinatory therapeutic strategy against NSCLC in the animal models.

  13. Inclusion Complex of Zerumbone with Hydroxypropyl-β-Cyclodextrin Induces Apoptosis in Liver Hepatocellular HepG2 Cells via Caspase 8/BID Cleavage Switch and Modulating Bcl2/Bax Ratio

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    Nabilah Muhammad Nadzri

    2013-01-01

    Full Text Available Zerumbone (ZER isolated from Zingiber zerumbet was previously encapsulated with hydroxypropyl-β-cyclodextrin (HPβCD to enhance ZER’s solubility in water, thus making it highly tolerable in the human body. The anticancer effects of this new ZER-HPβCD inclusion complex via apoptosis cell death were assessed in this study for the first time in liver hepatocellular cells, HepG2. Apoptosis was ascertained by morphological study, nuclear stain, and sub-G1 cell population accumulation with G2/M arrest. Further investigations showed the release of cytochrome c and loss of mitochondrial membrane potential, proving mitochondrial dysfunction upon the ZER-HPβCD treatment as well as modulating proapoptotic and anti-apototic Bcl-2 family members. A significant increase in caspase 3/7, caspase 9, and caspase 8 was detected with the depletion of BID cleaved by caspase 8. Collectively, these results prove that a highly soluble inclusion complex of ZER-HPβCD could be a promising anticancer agent for the treatment of hepatocellular carcinoma in humans.

  14. TRAIL Activates a Caspase 9/7-Dependent Pathway in Caspase 8/10-Defective SK-N-SH Neuroblastoma Cells with Two Functional End Points: Induction of Apoptosis and PGE2 Release

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    Giorgio Zauli

    2003-09-01

    Full Text Available Most neuroblastoma cell lines do not express apical caspases 8 and 10, which play a key role in mediating tumor necrosis factor-related apoptosis-inducing ligand (TRAIL cytotoxicity in a variety of malignant cell types. In this study, we demonstrated that TRAIL induced a moderate but significant increase of apoptosis in the caspase 8/10-deficient SK-N-SH neuroblastoma cell line, through activation of a novel caspase 9/7 pathway. Concomitant to the induction of apoptosis, TRAIL also promoted a significant increase of prostaglandin E2 (PGE2 release by SKN-SH cells. Moreover, coadministration of TRAIL plus indomethacin, a pharmacological inhibitor of cyclooxygenase (COX, showed an additive effect on SKN-SH cell death. In spite of the ability of TRAIL to promote the phosphorylation of both ERKi/2 and p38/MAPK, which have been involved in the control of COX expression/activity, neither PD98059 nor SB203580, pharmacological inhibitors of the ERKi/2 and p38/MAPK pathways, respectively, affected either PGE2 production or apoptosis induced by TRAIL. Finally, both induction of apoptosis and PGE2 release were completely abrogated by the broad caspase inhibitor z-VAD4mk, suggesting that both biologic end points were regulated in SK-N-SH cells through a caspase 9/7-dependent pathway.

  15. DNA signals at isoform promoters.

    Science.gov (United States)

    Dai, Zhiming; Xiong, Yuanyan; Dai, Xianhua

    2016-01-01

    Transcriptional heterogeneity is extensive in the genome, and most genes express variable transcript isoforms. However, whether variable transcript isoforms of one gene are regulated by common promoter elements remain to be elucidated. Here, we investigated whether isoform promoters of one gene have separated DNA signals for transcription and translation initiation. We found that TATA box and nucleosome-disfavored DNA sequences are prevalent in distinct transcript isoform promoters of one gene. These DNA signals are conserved among species. Transcript isoform has a RNA-determined unstructured region around its start site. We found that these DNA/RNA features facilitate isoform transcription and translation. These results suggest a DNA-encoded mechanism by which transcript isoform is generated. PMID:27353836

  16. Differential roles of PML isoforms

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    MouniraKChelbi-Alix

    2013-05-01

    Full Text Available The tumor suppressor promyelocytic leukemia protein (PML is fused to the retinoic acid receptor alpha in patients suffering from acute promyelocytic leukemia (APL. Treatment of APL patients with arsenic trioxide (As2O3 reverses the disease phenotype by a process involving the degradation of the fusion protein via its PML moiety. Several PML isoforms are generated from a single PML gene by alternative splicing. They share the same N-terminal region containing the RBCC/TRIM motif but differ in their C-terminal sequences. Recent studies of all the PML isoforms reveal the specific functions of each. Here, we review the nomenclature and structural organization of the PML isoforms in order to clarify the various designations and classifications found in different databases. The functions of the PML isoforms and their differential roles in antiviral defense also are reviewed. Finally, the key players involved in the degradation of the PML isoforms in response to As2O3 or other inducers are discussed.

  17. Inference of Isoforms from Short Sequence Reads

    Science.gov (United States)

    Feng, Jianxing; Li, Wei; Jiang, Tao

    Due to alternative splicing events in eukaryotic species, the identification of mRNA isoforms (or splicing variants) is a difficult problem. Traditional experimental methods for this purpose are time consuming and cost ineffective. The emerging RNA-Seq technology provides a possible effective method to address this problem. Although the advantages of RNA-Seq over traditional methods in transcriptome analysis have been confirmed by many studies, the inference of isoforms from millions of short sequence reads (e.g., Illumina/Solexa reads) has remained computationally challenging. In this work, we propose a method to calculate the expression levels of isoforms and infer isoforms from short RNA-Seq reads using exon-intron boundary, transcription start site (TSS) and poly-A site (PAS) information. We first formulate the relationship among exons, isoforms, and single-end reads as a convex quadratic program, and then use an efficient algorithm (called IsoInfer) to search for isoforms. IsoInfer can calculate the expression levels of isoforms accurately if all the isoforms are known and infer novel isoforms from scratch. Our experimental tests on known mouse isoforms with both simulated expression levels and reads demonstrate that IsoInfer is able to calculate the expression levels of isoforms with an accuracy comparable to the state-of-the-art statistical method and a 60 times faster speed. Moreover, our tests on both simulated and real reads show that it achieves a good precision and sensitivity in inferring isoforms when given accurate exon-intron boundary, TSS and PAS information, especially for isoforms whose expression levels are significantly high.

  18. FSH isoform pattern in classic galactosemia

    OpenAIRE

    Gubbels, Cynthia S.; Thomas, Chris M.G.; Wodzig, Will K. W. H.; Olthaar, André J.; Jaeken, Jaak; Sweep, Fred C. G. J.; Rubio-Gozalbo, M. Estela

    2010-01-01

    Female classic galactosemia patients suffer from primary ovarian insufficiency (POI). The cause for this long-term complication is not fully understood. One of the proposed mechanisms is that hypoglycosylation of complex molecules, a known secondary phenomenon of galactosemia, leads to FSH dysfunction. An earlier study showed less acidic isoforms of FSH in serum samples of two classic galactosemia patients compared to controls, indicating hypoglycosylation. In this study, FSH isoform patterns...

  19. Isoform Specificity of Protein Kinase Cs in Synaptic Plasticity

    Science.gov (United States)

    Sossin, Wayne S.

    2007-01-01

    Protein kinase Cs (PKCs) are implicated in many forms of synaptic plasticity. However, the specific isoform(s) of PKC that underlie(s) these events are often not known. We have used "Aplysia" as a model system in order to investigate the isoform specificity of PKC actions due to the presence of fewer isoforms and a large number of documented…

  20. PKC Isoform Expression in Modeled Microgravity

    Science.gov (United States)

    Risin, Diana; Sundaresan, Alamelu; Pellis, Neal R.; Dawson, David L. (Technical Monitor)

    1999-01-01

    Our previous studies showed that modeled (MMG) and true (USA Space Shuttle Missions STS-54 and STS-56) microgravity (MG) inhibit human lymphocyte locomotion, Modeled MG also suppressed polyclonal and antigen-specific lymphocyte activation. Activation of PKC by phorbol myristate acetate (PMA) restored the microgravity-inhibited lymphocyte locomotion as well as activation by phytohaemagglutinin (PHA), whereas calcium ionophore (ionomycin) was unable to restore these functions. Based on these results we hypothesized that MG-induced changes in lymphocyte functions are caused by a fundamental defect in signal transduction mechanism. This defect may be localized either at the PKC level or upstream of PKC, most likely, at the cell membrane level. In this study we examined the expression of PKC isoforms alpha, epsilon and delta in PBMC cultured in rotating wall vessel bioreactor, developed at NASA JSC, which models microgravity by sustaining cells in continuous free fall. The assessment of the isoforms was performed by FACS analysis following cell permeabilization. A decrease in the expression of isoforms epsilon and delta, but not isoform a, was observed in PBMC cultured in microgravity conditions. These data suggest that MMG might selectively affect the expression of Ca2+ independent isoforms of PKC Molecular analysis confirm selective suppression of Ca2+ independent isoforms of PKC.

  1. Absolute Quantification of Endogenous Ras Isoform Abundance.

    Directory of Open Access Journals (Sweden)

    Craig J Mageean

    Full Text Available Ras proteins are important signalling hubs situated near the top of networks controlling cell proliferation, differentiation and survival. Three almost identical isoforms, HRAS, KRAS and NRAS, are ubiquitously expressed yet have differing biological and oncogenic properties. In order to help understand the relative biological contributions of each isoform we have optimised a quantitative proteomics method for accurately measuring Ras isoform protein copy number per cell. The use of isotopic protein standards together with selected reaction monitoring for diagnostic peptides is sensitive, robust and suitable for application to sub-milligram quantities of lysates. We find that in a panel of isogenic SW48 colorectal cancer cells, endogenous Ras proteins are highly abundant with ≥260,000 total Ras protein copies per cell and the rank order of isoform abundance is KRAS>NRAS≥HRAS. A subset of oncogenic KRAS mutants exhibit increased total cellular Ras abundance and altered the ratio of mutant versus wild type KRAS protein. These data and methodology are significant because Ras protein copy number is required to parameterise models of signalling networks and informs interpretation of isoform-specific Ras functional data.

  2. Ikaros isoforms:The saga continues

    Institute of Scientific and Technical Information of China (English)

    Laura; A; Perez-Casellas; Aleksandar; Savic; Sinisa; Dovat

    2011-01-01

    Through alternate splicing,the Ikaros gene produces multiple proteins.Ikaros is essential for normal hematopoiesis and possesses tumor suppressor activity.Ikaros isoforms interact to form dimers and potentially multimeric complexes.Diverse Ikaros complexes produced by the presence of different Ikaros isoforms are hypothesized to confer distinct functions.Small dominantnegative Ikaros isoforms have been shown to inhibit the tumor suppressor activity of full-length Ikaros.Here,we describe how Ikaros activity is regulated by the coordinated expression of the largest Ikaros isoforms IK-1 and IK-H.Although IK-1 is described as full-length Ikaros,IK-H is the longest Ikaros isoform.IK-H,which includes residues coded by exon 3B (60 bp that lie between exons 3 and 4),is abundant in human but not murine hematopoietic cells.Specific residues that lie within the 20 amino acids encoded by exon 3B give IK-H DNA-binding characteristics that are distinct from those of IK-1.Moreover,IK-H can potentiate or inhibit the ability of IK-1 to bind DNA.IK-H binds to the regulatory regions of genes that are upregulated by Ikaros,but not genes that are repressed by Ikaros.Although IK-1 localizes to pericentromeric heterochromatin,IK-H can be found in both pericentromeric and non-pericentromeric locations.Anti-silencing activity of gamma satellite DNA has been shown to depend on the binding of IK-H,but not other Ikaros isoforms.The unique features of IK-H,its influence on Ikaros activity,and the lack of IK-H expression in mice suggest that Ikaros function in humans may be more complex and possibly distinct from that in mice.

  3. p53 isoforms change p53 paradigm

    OpenAIRE

    Bourdon, JC

    2014-01-01

    Although p53 defines cellular responses to cancer treatment it is not clear how p53 can be used to control cell fate outcome. Data demonstrate that so-called p53 does not exist as a single protein, but is in fact a group of p53 protein isoforms whose expression can be manipulated to control the cellular response to treatment.

  4. New isoforms of rat Aquaporin-4

    DEFF Research Database (Denmark)

    Moe, Svein Erik; Sorbo, Jan Gunnar; Søgaard, Rikke;

    2008-01-01

    Aquaporin-4 (AQP4) is a brain aquaporin implicated in the pathophysiology of numerous clinical conditions including brain edema. Here we show that rat AQP4 has six cDNA isoforms, formed by alternative splicing. These are named AQP4a-f, where AQP4a and AQP4c correspond to the two classical M1 and M...

  5. Differential water permeability and regulation of three aquaporin 4 isoforms

    DEFF Research Database (Denmark)

    Fenton, Robert A.; Moeller, Hanne B; Zelenina, Marina;

    2010-01-01

    Aquaporin 4 (AQP4) is expressed in the perivascular glial endfeet and is an important pathway for water during formation and resolution of brain edema. In this study, we examined the functional properties and relative unit water permeability of three functional isoforms of AQP4 expressed...... in the brain (M1, M23, Mz). The M23 isoform gave rise to square arrays when expressed in Xenopus laevis oocytes. The relative unit water permeability differed significantly between the isoforms in the order of M1 > Mz > M23. None of the three isoforms were permeable to small osmolytes nor were they affected...... by changes in external K(+) concentration. Upon protein kinase C (PKC) activation, oocytes expressing the three isoforms demonstrated rapid reduction of water permeability, which correlated with AQP4 internalization. The M23 isoform was more sensitive to PKC regulation than the longer isoforms...

  6. Lipoprotein lipase isoelectric point isoforms in humans

    DEFF Research Database (Denmark)

    Badia-Villanueva, M.; Carulla, P.; Carrascal, M.;

    2014-01-01

    characterization of these forms was carried out by 2DE combined with Western blotting and mass spectrometry (MALDI-TOF/MS and LC-MS/MS). Further studies are needed to discover their molecular origin, the pattern of pI isoforms in human tissues, their possible physiological functions and possible modifications of......-heparin plasma (PHP), LPL consists of a pattern of more than 8 forms of the same apparent molecular weight, but different isoelectric point (pI). In the present study we describe, for the first time, the existence of at least nine LPL pI isoforms in human PHP, with apparent pI between 6.8 and 8.6. Separation and...

  7. EASI—enrichment of alternatively spliced isoforms

    OpenAIRE

    Julian P Venables; Burn, John

    2006-01-01

    Alternative splicing produces more than one protein from the majority of genes and the rarer forms can have dominant functions. Instability of alternative transcripts can also hinder the study of regulation of gene expression by alternative splicing. To investigate the true extent of alternative splicing we have developed a simple method of enriching alternatively spliced isoforms (EASI) from PCRs using beads charged with Thermus aquaticus single-stranded DNA-binding protein (T.Aq ssb). This ...

  8. Functional studies of sodium pump isoforms

    DEFF Research Database (Denmark)

    Clausen, Michael Jakob

    The Na+,K+-ATPase is an essential ion pump found in all animal cells. It uses the energy from ATP hydrolysis to export three Na+ and import two K+, both against their chemical gradients and for Na+ also against the electrical potential. Mammals require four Na+,K+-ATPase isoforms that each have...... synthesized cohorts of pumps from the Golgi apparatus to the plasma membrane....

  9. Localization and functional characterization of the human NKCC2 isoforms

    DEFF Research Database (Denmark)

    Carota, I; Theilig, F; Oppermann, M;

    2010-01-01

    inhibited by bumetanide than by furosemide. A sequence analysis of the amino acids encoded by exon 4 variants revealed high similarities between human and rodent NKCC2 isoforms, suggesting that differences in ion transport characteristics between species may be related to sequence variations outside the...... isoforms have specific localizations and transport characteristics, as assessed for rabbit, rat and mouse. In the present study, we aimed to address the localization and transport characteristics of the human NKCC2 isoforms. METHODS: RT-PCR, in situ hybridization and uptake studies in Xenopus oocytes were...... performed to characterize human NKCC2 isoforms. RESULTS: All three classical NKCC2 isoforms were detected in the human kidney; in addition, we found splice variants with tandem duplicates of the variable exon 4. Contrary to rodents, in which NKCC2F is the most abundant NKCC2 isoform, NKCC2A was the dominant...

  10. Tumorigenic properties of alternative osteopontin isoforms in mesothelioma

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, Sergey V., E-mail: Sergey.Ivanov@med.nyu.edu [Thoracic Surgery Laboratory, Cardiothoracic Surgery Department, NYU Langone Medical Center, 462 First Ave., Bellevue Hospital, Room 15N20, NY 10016 (United States); Ivanova, Alla V.; Goparaju, Chandra M.V.; Chen, Yuanbin; Beck, Amanda; Pass, Harvey I. [Thoracic Surgery Laboratory, Cardiothoracic Surgery Department, NYU Langone Medical Center, 462 First Ave., Bellevue Hospital, Room 15N20, NY 10016 (United States)

    2009-05-08

    Osteopontin (SPP1) is an inflammatory cytokine that we previously characterized as a diagnostic marker in patients with asbestos-induced malignant mesothelioma (MM). While SPP1 shows both pro- and anti-tumorigenic biological effects, little is known about the molecular basis of these activities. In this study, we demonstrate that while healthy pleura possesses all three differentially spliced SPP1 isoforms (A-C), in clinical MM specimens isoform A is markedly up-regulated and predominant. To provide a clue to possible functions of the SPP1 isoforms we next performed their functional evaluation via transient expression in MM cell lines. As a result, we report that isoforms A-C demonstrate different activities in cell proliferation, wound closure, and invasion assays. These findings suggest different functions for SPP1 isoforms and underline pro-tumorigenic properties of isoforms A and B.

  11. A novel functional rabbit IL- 7 isoform

    OpenAIRE

    Siewe, Basile T.; Kalis, Susan L.; Esteves, Pedro J; Zhou, Tong; Knight, Katherine L.

    2010-01-01

    IL-7 is required for B cell development in mouse and is a key regulator of T cell development and peripheral T cell homeostasis in mouse and human. Recently, we found that IL-7 is expressed in rabbit bone marrow and in vitro, is required for differentiation of lymphoid progenitors to B and T lineage cells. Herein, we report the identification of a novel rabbit IL-7 isoform, IL-7II. Recombinant IL-7II (rIL-7II) binds lymphocytes via the IL-7R and induces phosphorylation of STAT5. Further, rIL-...

  12. Androgen receptor isoforms in human and rat prostate

    Institute of Scientific and Technical Information of China (English)

    Shu-JieXIA; Gang-YaoHAO; Xiao-DaTANG

    2000-01-01

    Aim: To investigate the androgen receptor (AR) isoforms and its variability of expression in human and rat prostatic tissues. Methods: Human benign prostatic hyperplasia (BPH) and prostatic cancer tissues were obtained from patients undergoing prostatectomy, and rat ventral prostate was incised 3 days after castration. Forty-one AR-positive BPH specimens, 3 prostatic cancer specimens, and 6 rat prostates were used. After processing at 4℃, the tissues were examined by means of high resolution isoelectric focusing (IEF) technique to determine their AR isoforms. Results:From the prostatic specimens, 3 types of AR isoforms were detected with pI values at 6.5, 6.0, and 5.3. In human BPH tissues, 15/41 (36.6%) specimens showed all the three types of isoforms, while 19/41 (46.3%) showed 2 isoforms at various combinations and 7/41(17.1%), 1 isoform. For the 3 prostatic cancer specimens, one showed 3 isoforms, one, 2 isoforms, and the other failed to show any isoform. All rat prostatic tissues showed 2 isoforms at different combinations. Binding of 3H-dihydrotestosterone (DHT) to the isoforms was inhibited by the addition of 100-fold excess of DHT or testosterone, but not progesterone, oestradiol or diethylstilboestrol. Conclusion: AR isoforms are different in different patients. Although their genesis is not clear, the therapeutic implication of the present observation appears to be interesting, that may help clarifying the individual differences in the response to hormonal therapy.(Asian J Androl 2000 Dec;2:307-310)

  13. Identification of a novel TDRD7 isoforms

    Directory of Open Access Journals (Sweden)

    Filonenko V. V.

    2011-12-01

    Full Text Available The aim of our study was to investigate the tudor domain-containing protein 7 (TDRD7 subcellular localization, which could be linked to diverse functions of this protein within the cell. Methods. In this study we employed cell imaging technique for detecting TDRD7 subcellular localization, Western blot analysis of HEK293 cell fractions with anti-TDRD7 monoclonal antibodies and bioinformatical search of possible TDRD7 isoforms in Uniprot, Ensemble, UCSC databases. Results. We have observed specific TDRD7-containing structures in cytoplasm as well as in the nucleus in HEK293 cells. The Western blot analysis of subcellular fractions (cytoplasm, mitochondria, nucleus allowed us to detect three lower immunoreactive bands, with the aproximate molecular weight of 130, 110 and 60 kDa (we termed them as TDRD7, TDRD7 and TDRD7 and specific subcellular localization. The bioinformatical analysis of TDRD7 primary structure allowed us to determine two alternative transcripts from TDRD7 gene coding for proteins with calculated molecular weight of 130 and 60 kDa. Conclusion. The presented data demonstrate the existence at protein level of potential TDRD7 isoforms: TDRD7, TDRD7 and TDRD7. The expression profile of these splice variants and their role in cells remains to be elucidated.

  14. Spinach pyruvate kinase isoforms: partial purification and regulatory properties

    Energy Technology Data Exchange (ETDEWEB)

    Baysdorfer, C.; Bassham, J.A.

    1984-02-01

    Pyruvate kinase from spinach (Spinacea oleracea L.) leaves consists of two isoforms, separable by blue agarose chromatography. Both isoforms share similar pH profiles and substrate and alternate nucleotide K/sub m/ values. In addition, both isoforms are inhibited by oxalate and ATP and activated by AMP. The isoforms differ in their response to three key metabolites; citrate, aspartate, and glutamate. The first isoform is similar to previously reported plant pyruvate kinases in its sensitivity to citrate inhibition. The K/sub i/ for this inhibition is 1.2 millimolar citrate. The second isoform is not affected by citrate but is regulated by aspartate and glutamate. Aspartate is an activator with a K/sub a/ of 0.05 millimolar, and glutamate is an inhibitor with a K/sub i/ of 0.68 millimolar. A pyruvate kinase with these properties has not been previously reported. Based on these considerations, the authors suggest that the activity of the first isoform is regulated by respiratory metabolism. The second isoform, in contrast, may be regulated by the demand for carbon skeletons for use in ammonia assimilation.

  15. Expression, purification and enzymatic characterization of the catalytic domains of human tryptophan hydroxylase isoforms

    DEFF Research Database (Denmark)

    Windahl, Michael Skovbo; Boesen, Jane; Karlsen, Pernille Efferbach; Christensen, Hans Erik Mølager

    Tryptophan hydroxylase exists in two isoforms: Isoform 1 catalyses the first and rate-limiting step in the synthesis of serotonin in the peripheral parts of the body while isoform 2 catalyses this step in the brain. The catalytic domains of human tryptophan hydroxylase 1 and 2 have been expressed......, purified and the kinetic properties have been studied and are compared. Substrate inhibition by tryptophan is observed for isoform 1 but not for isoform 2. Large differences are observed in the K m,tetrahydrobiopterin values for the two isoforms, being >10 times larger for isoform 1 compared to isoform 2....

  16. p53 Family: Role of Protein Isoforms in Human Cancer

    Directory of Open Access Journals (Sweden)

    Jinxiong Wei

    2012-01-01

    Full Text Available TP53, TP63, and TP73 genes comprise the p53 family. Each gene produces protein isoforms through multiple mechanisms including extensive alternative mRNA splicing. Accumulating evidence shows that these isoforms play a critical role in the regulation of many biological processes in normal cells. Their abnormal expression contributes to tumorigenesis and has a profound effect on tumor response to curative therapy. This paper is an overview of isoform diversity in the p53 family and its role in cancer.

  17. Specific regulation of NRG1 isoform expression by neuronal activity

    OpenAIRE

    Liu, Xihui; Bates, Ryan; Wang, Fay; Su, Nan; Kirov, Sergei A.; Luo, Yuling; Wang, Jian-Zhi; Xiong, Wen-Cheng; Mei, Lin

    2011-01-01

    Neuregulin 1 (NRG1) is a trophic factor that has been implicated in neural development, neurotransmission and synaptic plasticity. NRG1 has multiple isoforms that are generated by usage of different promoters and alternative splicing of a single gene. However, little is known about NRG1 isoform composition profile, whether it changes during development or the underlying mechanisms. We found that each of the six types of NRG1 has a distinct expression pattern in the brain at different ages, re...

  18. A Network of Splice Isoforms for the Mouse.

    Science.gov (United States)

    Li, Hong-Dong; Menon, Rajasree; Eksi, Ridvan; Guerler, Aysam; Zhang, Yang; Omenn, Gilbert S; Guan, Yuanfang

    2016-01-01

    The laboratory mouse is the primary mammalian species used for studying alternative splicing events. Recent studies have generated computational models to predict functions for splice isoforms in the mouse. However, the functional relationship network, describing the probability of splice isoforms participating in the same biological process or pathway, has not yet been studied in the mouse. Here we describe a rich genome-wide resource of mouse networks at the isoform level, which was generated using a unique framework that was originally developed to infer isoform functions. This network was built through integrating heterogeneous genomic and protein data, including RNA-seq, exon array, protein docking and pseudo-amino acid composition. Through simulation and cross-validation studies, we demonstrated the accuracy of the algorithm in predicting isoform-level functional relationships. We showed that this network enables the users to reveal functional differences of the isoforms of the same gene, as illustrated by literature evidence with Anxa6 (annexin a6) as an example. We expect this work will become a useful resource for the mouse genetics community to understand gene functions. The network is publicly available at: http://guanlab.ccmb.med.umich.edu/isoformnetwork. PMID:27079421

  19. Differential regulation of renal phospholipase C isoforms by catecholamines.

    Science.gov (United States)

    Yu, P Y; Asico, L D; Eisner, G M; Jose, P A

    1995-01-01

    Dopamine and D1 agonists and NE all increase phosphatidyl inositol-specific phospholipase C (PLC) activity, but whereas dopamine produces a natriuresis, NE has an antinatriuretic effect. To determine if catecholamines differentially regulate the expression of PLC isoforms, we infused fenoldopam, a D1 agonist, or pramipexole, a D1/D2 agonist, intravenously or infused fenoldopam or NE into the renal artery of anesthetized rats. After 3-4 h of infusion, when the expected natriuresis (fenoldopam or pramipexole) or antinatriuresis (NE) occurred, the kidneys were removed for analysis of PLC isoform protein expression activity. Western blot analysis revealed that in renal cortical membranes, fenoldopam and pramipexole increased expression of PLC beta 1 and decreased expression of PLC gamma 1; PLC delta was unchanged. In the cytosol, pramipexole and fenoldopam increased expression of both PLC beta 1 and PLC gamma 1. No effects were noted in the medulla. A preferential D1 antagonist, SKF 83742, which by itself had no effect, blocked the effects of pramipexole, thus confirming the involvement of the D1 receptor. In contrast, NE also increased PLC beta 1 but did not affect PLC gamma 1 protein expression in membranes. The changes in PLC isoform expression were accompanied by similar changes in PLC isoform activity. These studies demonstrate for the first time differential regulation of PLC isoforms by catecholamines. PMID:7814630

  20. SURVIV for survival analysis of mRNA isoform variation.

    Science.gov (United States)

    Shen, Shihao; Wang, Yuanyuan; Wang, Chengyang; Wu, Ying Nian; Xing, Yi

    2016-01-01

    The rapid accumulation of clinical RNA-seq data sets has provided the opportunity to associate mRNA isoform variations to clinical outcomes. Here we report a statistical method SURVIV (Survival analysis of mRNA Isoform Variation), designed for identifying mRNA isoform variation associated with patient survival time. A unique feature and major strength of SURVIV is that it models the measurement uncertainty of mRNA isoform ratio in RNA-seq data. Simulation studies suggest that SURVIV outperforms the conventional Cox regression survival analysis, especially for data sets with modest sequencing depth. We applied SURVIV to TCGA RNA-seq data of invasive ductal carcinoma as well as five additional cancer types. Alternative splicing-based survival predictors consistently outperform gene expression-based survival predictors, and the integration of clinical, gene expression and alternative splicing profiles leads to the best survival prediction. We anticipate that SURVIV will have broad utilities for analysing diverse types of mRNA isoform variation in large-scale clinical RNA-seq projects. PMID:27279334

  1. Vitamin E Isoforms as Modulators of Lung Inflammation

    Directory of Open Access Journals (Sweden)

    Hiam Abdala-Valencia

    2013-10-01

    Full Text Available Asthma and allergic diseases are complex conditions caused by a combination of genetic and environmental factors. Clinical studies suggest a number of protective dietary factors for asthma, including vitamin E. However, studies of vitamin E in allergy commonly result in seemingly conflicting outcomes. Recent work indicates that allergic inflammation is inhibited by supplementation with the purified natural vitamin E isoform α-tocopherol but elevated by the isoform γ-tocopherol when administered at physiological tissue concentrations. In this review, we discuss opposing regulatory effects of α-tocopherol and γ-tocopherol on allergic lung inflammation in clinical trials and in animal studies. A better understanding of the differential regulation of inflammation by isoforms of vitamin E provides a basis towards the design of clinical studies and diets that would effectively modulate inflammatory pathways in lung disease.

  2. Isoforms of murine and human serum amyloid P component

    DEFF Research Database (Denmark)

    Nybo, Mads; Hackler, R; Kold, B;

    1998-01-01

    affect their number. When the acute-phase response was analysed in three mouse strains, CBA/J and C3H/HeN initially showed seven SAP isoforms in serum and C57BL/6 J three or four. The responses in all three strains peaked at day 2 and were normalized within 14 days. On days 2 and 4, CBA/J and C3H......Isoelectric focusing (IEF) and immunofixation of murine serum amyloid P component (SAP), purified and in serum, showed a distinct and strain-dependent isoform pattern with up to seven bands (pI 5.1-5.7). Neuraminidase treatment caused a shift of the isoforms to more basic pI values, but did not...

  3. Oxygenation properties and isoform diversity of snake hemoglobins

    DEFF Research Database (Denmark)

    Storz, Jay F.; Natarajan, Chandrasekhar; Moriyama, Hideaki;

    2015-01-01

    Available data suggest that snake hemoglobins (Hbs) are characterized by a combination of unusual structural and functional properties relative to the Hbs of other amniote vertebrates, including oxygenation-linked tetramer- dimer dissociation. However, standardized comparative data are lacking for...... snake Hbs, and the Hb isoform composition of snake red blood cells has not been systematically characterized. Here we present the results of an integrated analysis of snake Hbs and the underlying - and -type globin genes to characterize 1) Hb isoform composition of definitive erythrocytes, and 2) the...... oxygenation properties of isolated isoforms as well as composite hemolysates. We used species from three families as subjects for experimental studies of Hb function: South American rattlesnake, Crotalus durissus (Viperidae); Indian python, Python molurus (Pythonidae); and yellow-bellied sea snake, Pelamis...

  4. Laminin isoforms in endothelial and perivascular basement membranes

    Science.gov (United States)

    Yousif, Lema F.; Di Russo, Jacopo; Sorokin, Lydia

    2013-01-01

    Laminins, one of the major functional components of basement membranes, are found underlying endothelium, and encasing pericytes and smooth muscle cells in the vessel wall. Depending on the type of blood vessel (capillary, venule, postcapillary venule, vein or artery) and their maturation state, both the endothelial and mural cell phenotype vary, with associated changes in laminin isoform expression. Laminins containing the α4 and α5 chains are the major isoforms found in the vessel wall, with the added contribution of laminin α2 in larger vessels. We here summarize current data on the precise localization of these laminin isoforms and their receptors in the different layers of the vessel wall, and their potential contribution to vascular homeostasis. PMID:23263631

  5. Identification and characterization of novel NuMA isoforms

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Jin, E-mail: petersdu2112@hotmail.com [Key Laboratory for Cell Proliferation and Regulation of the Ministry of Education, Beijing Normal University, Beijing (China); Xu, Zhe [Department of Clinical Laboratory Diagnosis, Beijing Tiantan Hospital, Capital Medical University, Beijing (China); Core Laboratory for Clinical Medical Research, Beijing Tiantan Hospital, Capital Medical University, Beijing (China); He, Dacheng [Key Laboratory for Cell Proliferation and Regulation of the Ministry of Education, Beijing Normal University, Beijing (China); Lu, Guanting, E-mail: guantlv@126.com [Beijing DnaLead Science and Technology Co., LTD, Beijing (China)

    2014-11-21

    Highlights: • Seven NuMA isoforms generated by alternative splicing were categorized into 3 groups: long, middle and short. • Both exons 15 and 16 in long NuMA were “hotspot” for alternative splicing. • Lower expression of short NuMA was observed in cancer cells compared with nonneoplastic controls. • Distinct localization pattern of short isoforms indicated different function from that of long and middle NuMA. - Abstract: The large nuclear mitotic apparatus (NuMA) has been investigated for over 30 years with functions related to the formation and maintenance of mitotic spindle poles during mitosis. However, the existence and functions of NuMA isoforms generated by alternative splicing remains unclear. In the present work, we show that at least seven NuMA isoforms (categorized into long, middle and short groups) generated by alternative splicing from a common NuMA mRNA precursor were discovered in HeLa cells and these isoforms differ mainly at the carboxyl terminus and the coiled-coil domains. Two “hotspot” exons with molecular mass of 3366-nt and 42-nt tend to be spliced during alternative splicing in long and middle groups. Furthermore, full-length coding sequences of long and middle NuMA obtained by using fusion PCR were constructed into GFP-tagged vector to illustrate their cellular localization. Long NuMA mainly localized in the nucleus with absence from nucleoli during interphase and translocated to the spindle poles in mitosis. Middle NuMA displayed the similar cell cycle-dependent distribution pattern as long NuMA. However, expression of NuMA short isoforms revealed a distinct subcellular localization. Short NuMA were present in the cytosol during the whole cycle, without colocalization with mitotic apparatus. These results have allowed us tentatively to explore a new research direction for NuMA’s various functions.

  6. Apolipoprotein E isoform-specific effects on lipoprotein receptor processing.

    Science.gov (United States)

    Bachmeier, Corbin; Shackleton, Ben; Ojo, Joseph; Paris, Daniel; Mullan, Michael; Crawford, Fiona

    2014-12-01

    Recent findings indicate an isoform-specific role for apolipoprotein E (apoE) in the elimination of beta-amyloid (Aβ) from the brain. ApoE is closely associated with various lipoprotein receptors, which contribute to Aβ brain removal via metabolic clearance or transit across the blood–brain barrier (BBB). These receptors are subject to ectodomain shedding at the cell surface, which alters endocytic transport and mitigates Aβ elimination. To further understand the manner in which apoE influences Aβ brain clearance, these studies investigated the effect of apoE on lipoprotein receptor shedding. Consistent with prior reports, we observed an increased shedding of the low-density lipoprotein receptor (LDLR) and the LDLR-related protein 1 (LRP1) following Aβ exposure in human brain endothelial cells. When Aβ was co-treated with each apoE isoform, there was a reduction in Aβ-induced shedding with apoE2 and apoE3, while lipoprotein receptor shedding in the presence of apoE4 remained increased. Likewise, intracranial administration of Aβ to apoE-targeted replacement mice (expressing the human apoE isoforms) resulted in an isoform-dependent effect on lipoprotein receptor shedding in the brain (apoE4 > apoE3 > apoE2). Moreover, these results show a strong inverse correlation with our prior work in apoE transgenic mice in which apoE4 animals showed reduced Aβ clearance across the BBB compared to apoE3 animals. Based on these results, apoE4 appears less efficient than other apoE isoforms in regulating lipoprotein receptor shedding, which may explain the differential effects of these isoforms in removing Aβ from the brain. PMID:25015123

  7. Molecular regulation of skeletal muscle myosin heavy chain isoforms

    OpenAIRE

    Brown, David M.

    2015-01-01

    Research investigating the regulation of muscle fibre type has traditionally been conducted in vivo, analyzing global changes at a whole muscle level. Broadly, this thesis aimed to explore more “molecular” approaches, utilizing molecular and cell biology to understand the expression and regulation of myosin heavy chain (MyHC) isoforms as an indicator of muscle fibre composition. The mRNA expression profile of six MyHC isoform genes during C2C12 myogenesis was elucidated to reveal that the...

  8. A Review of Metallothionein Isoforms and their Role in Pathophysiology

    OpenAIRE

    Senthil kumar M; Manisenthil Kumar KT; Shyam Sunder A; Thirumoorthy N; Ganesh GNK; Chatterjee Malay

    2011-01-01

    Abstract The Metallothionein (MT) is a protein which has several interesting biological effects and has been demonstrated increase focus on the role of MT in various biological systems in the past three decades. The studies on the role of MT were limited with few areas like apoptosis and antioxidants in selected organs even fifty years after its discovery. Now acknowledge the exploration of various isoforms of MT such as MT-I, MT-II, MT-III and MT-IV and other isoforms in various biological s...

  9. Role of p53 isoforms and aggregations in cancer.

    Science.gov (United States)

    Kim, SeJin; An, Seong Soo A

    2016-06-01

    p53 is a master regulatory protein that is involved in diverse cellular metabolic processes such as apoptosis, DNA repair, and cell cycle arrest. The protective function of p53 (in its homotetrameric form) as a tumor suppressor is lost in more than 50% of human cancers.Despite considerable experimental evidence suggesting the presence of multiple p53 states, it has been difficult to correlate the status of p53 with cancer response to treatments and clinical outcomes, which suggest the importance of complex but essential p53 regulatory pathways.Recent studies have indicated that the expression pattern of p53 isoforms may play a crucial role in regulating normal and cancer cell fates in response to diverse stresses. The human TP53 gene encodes at least 12 p53 isoforms, which are produced in normal tissue through alternative initiation of translation, usage of alternative promoters, and alternative splicing. Furthermore, some researchers have suggested that the formation of mutant p53 aggregates may be associated with cancer pathogenesis due to loss-of function (LoF), dominant-negative (DN), and gain-of function (GoF) effects.As different isoforms or the aggregation state of p53 may influence tumorigenesis, this review aims to examine the correlation of p53 isoforms and aggregation with cancer. PMID:27368003

  10. APPRIS: annotation of principal and alternative splice isoforms.

    Science.gov (United States)

    Rodriguez, Jose Manuel; Maietta, Paolo; Ezkurdia, Iakes; Pietrelli, Alessandro; Wesselink, Jan-Jaap; Lopez, Gonzalo; Valencia, Alfonso; Tress, Michael L

    2013-01-01

    Here, we present APPRIS (http://appris.bioinfo.cnio.es), a database that houses annotations of human splice isoforms. APPRIS has been designed to provide value to manual annotations of the human genome by adding reliable protein structural and functional data and information from cross-species conservation. The visual representation of the annotations provided by APPRIS for each gene allows annotators and researchers alike to easily identify functional changes brought about by splicing events. In addition to collecting, integrating and analyzing reliable predictions of the effect of splicing events, APPRIS also selects a single reference sequence for each gene, here termed the principal isoform, based on the annotations of structure, function and conservation for each transcript. APPRIS identifies a principal isoform for 85% of the protein-coding genes in the GENCODE 7 release for ENSEMBL. Analysis of the APPRIS data shows that at least 70% of the alternative (non-principal) variants would lose important functional or structural information relative to the principal isoform. PMID:23161672

  11. Antagonistic functions of LMNA isoforms in energy expenditure and lifespan.

    Science.gov (United States)

    Lopez-Mejia, Isabel C; de Toledo, Marion; Chavey, Carine; Lapasset, Laure; Cavelier, Patricia; Lopez-Herrera, Celia; Chebli, Karim; Fort, Philippe; Beranger, Guillaume; Fajas, Lluis; Amri, Ez Z; Casas, Francois; Tazi, Jamal

    2014-05-01

    Alternative RNA processing of LMNA pre-mRNA produces three main protein isoforms, that is, lamin A, progerin, and lamin C. De novo mutations that favor the expression of progerin over lamin A lead to Hutchinson-Gilford progeria syndrome (HGPS), providing support for the involvement of LMNA processing in pathological aging. Lamin C expression is mutually exclusive with the splicing of lamin A and progerin isoforms and occurs by alternative polyadenylation. Here, we investigate the function of lamin C in aging and metabolism using mice that express only this isoform. Intriguingly, these mice live longer, have decreased energy metabolism, increased weight gain, and reduced respiration. In contrast, progerin-expressing mice show increased energy metabolism and are lipodystrophic. Increased mitochondrial biogenesis is found in adipose tissue from HGPS-like mice, whereas lamin C-only mice have fewer mitochondria. Consistently, transcriptome analyses of adipose tissues from HGPS and lamin C-only mice reveal inversely correlated expression of key regulators of energy expenditure, including Pgc1a and Sfrp5. Our results demonstrate that LMNA encodes functionally distinct isoforms that have opposing effects on energy metabolism and lifespan in mammals. PMID:24639560

  12. Comparison of liver oncogenic potential among human RAS isoforms

    Science.gov (United States)

    Chung, Sook In; Moon, Hyuk; Ju, Hye-Lim; Kim, Dae Yeong; Cho, Kyung Joo; Ribback, Silvia; Dombrowski, Frank; Calvisi, Diego F.; Ro, Simon Weonsang

    2016-01-01

    Mutation in one of three RAS genes (i.e., HRAS, KRAS, and NRAS) leading to constitutive activation of RAS signaling pathways is considered a key oncogenic event in human carcinogenesis. Whether activated RAS isoforms possess different oncogenic potentials remains an unresolved question. Here, we compared oncogenic properties among RAS isoforms using liver-specific transgenesis in mice. Hydrodynamic transfection was performed using transposons expressing short hairpin RNA downregulating p53 and an activated RAS isoform, and livers were harvested at 23 days after gene delivery. No differences were found in the hepatocarcinogenic potential among RAS isoforms, as determined by both gross examination of livers and liver weight per body weight ratio (LW/BW) of mice expressing HRASQ61L, KRAS4BG12V and NRASQ61K. However, the tumorigenic potential differed significantly between KRAS splicing variants. The LW/BW ratio in KRAS4AG12V mice was significantly lower than in KRAS4BG12V mice (p mice lived significantly longer than KRRAS4BG12V mice (p mice displayed higher expression of the p16INK4A tumor suppressor when compared with KRAS4BG12V tumors. Forced overexpression of p16INK4A significantly reduced tumor growth in KRAS4BG12V mice, suggesting that upregulation of p16INK4A by KRAS4AG12V presumably delays tumor development driven by the latter oncogene. PMID:26799184

  13. Tropomyosin-binding properties modulate competition between tropomodulin isoforms.

    Science.gov (United States)

    Colpan, Mert; Moroz, Natalia A; Gray, Kevin T; Cooper, Dillon A; Diaz, Christian A; Kostyukova, Alla S

    2016-06-15

    The formation and fine-tuning of cytoskeleton in cells are governed by proteins that influence actin filament dynamics. Tropomodulin (Tmod) regulates the length of actin filaments by capping the pointed ends in a tropomyosin (TM)-dependent manner. Tmod1, Tmod2 and Tmod3 are associated with the cytoskeleton of non-muscle cells and their expression has distinct consequences on cell morphology. To understand the molecular basis of differences in the function and localization of Tmod isoforms in a cell, we compared the actin filament-binding abilities of Tmod1, Tmod2 and Tmod3 in the presence of Tpm3.1, a non-muscle TM isoform. Tmod3 displayed preferential binding to actin filaments when competing with other isoforms. Mutating the second or both TM-binding sites of Tmod3 destroyed its preferential binding. Our findings clarify how Tmod1, Tmod2 and Tmod3 compete for binding actin filaments. Different binding mechanisms and strengths of Tmod isoforms for Tpm3.1 contribute to their divergent functional capabilities. PMID:27091317

  14. Cloning, expression and alternative splicing of the novel isoform of hTCP11 gene

    DEFF Research Database (Denmark)

    Ma, Yong-xin; Zhang, Si-zhong; Wu, Qia-qing;

    2003-01-01

    To identify a novel isoform of hTCP11 gene and investigate its expression and alternative splicing.......To identify a novel isoform of hTCP11 gene and investigate its expression and alternative splicing....

  15. Determination of the class and isoform selectivity of small-molecule histone deacetylase inhibitors

    DEFF Research Database (Denmark)

    Khan, N.; Jeffers, M.; Kumar, S.;

    2008-01-01

    ) against a panel of rhHDAC (recombinant human HDAC) isoforms. Eight rhHDACs were expressed using a baculoviral system, and a Fluor de Lystrade mark (Biomol International) HDAC assay was optimized for each purified isoform. The potency and selectivity of ten HDACs on class I isoforms (rhHDAC1, rhHDAC2, rh...

  16. One isoform of Arg/Abl2 tyrosine kinase is nuclear and the other seven cytosolic isoforms differently modulate cell morphology, motility and the cytoskeleton

    Energy Technology Data Exchange (ETDEWEB)

    Bianchi, Cristina; Torsello, Barbara; Di Stefano, Vitalba; Zipeto, Maria A.; Facchetti, Rita; Bombelli, Silvia; Perego, Roberto A., E-mail: roberto.perego@unimib.it

    2013-08-01

    The non-receptor tyrosine kinase Abelson related gene (Arg/Abl2) regulates cell migration and morphogenesis by modulating the cytoskeleton. Arg promotes actin-based cell protrusions and spreading, and inhibits cell migration by attenuating stress fiber formation and contractility via activation of the RhoA inhibitor, p190RhoGAP, and by regulating focal adhesion dynamics also via CrkII phosphorylation. Eight full-length Arg isoforms with different N- and C-termini are endogenously expressed in human cells. In this paper, the eight Arg isoforms, subcloned in the pFLAG-CMV2 vector, were transfected in COS-7 cells in order to study their subcellular distribution and role in cell morphology, migration and cytoskeletal modulation. The transfected 1BSCTS Arg isoform has a nuclear distribution and phosphorylates CrkII in the nucleus, whilst the other isoforms are detected in the cytoplasm. The 1BLCTL, 1BSCTL, 1ASCTS isoforms were able to significantly decrease stress fibers, induce cell shrinkage and filopodia-like protrusions with a significant increase in p190RhoGAP phosphorylation. In contrast, 1ALCTL, 1ALCTS, 1ASCTL and 1BLCTS isoforms do not significantly decrease stress fibers and induce the formation of retraction tail-like protrusions. The 1BLCTL and 1ALCTL isoforms have different effects on cell migration and focal adhesions. All these data may open new perspectives to study the mechanisms of cell invasiveness. -Highlights: • Each of the eight Arg isoforms was transfected in COS-7 cells. • Only the 1BSCTS Arg isoform has a nuclear distribution in transfected cells. • The cytoplasmic isoforms and F-actin colocalize cortically and in cell protrusions. • Arg isoforms differently phosphorylate p190RhoGAP and CrkII. • Arg isoforms differently modulate stress fibers, cell protrusions and motility.

  17. Differential regulation of macropinocytosis by Abi1/Hssh3bp1 isoforms.

    Directory of Open Access Journals (Sweden)

    Patrycja M Dubielecka

    Full Text Available BACKGROUND: Macropinocytosis, which is a constitutive cellular process of fluid and macromolecule uptake, is regulated by actin cytoskeleton rearrangements near the plasma membrane. Activation of Rac1, which is proposed to act upstream of the actin polymerization regulatory Wave 2 complex, has been found to correlate with enhanced macropinocytosis. One of the components of the Wave 2 complex is Abi1. Multiple, alternatively spliced isoforms of Abi1 are expressed in mammalian cells, but the functional significance of the various isoforms is unknown. PRINCIPAL FINDINGS: Here, using flow cytometric assay analysis for Alexa Fluor 647, we demonstrate that Abi1 isoforms 2 and 3 differentially regulate macropinocytosis. LNCaP cells expressing isoform 3 had increased macropinocytic uptake that correlated with enhanced cell spreading and higher Rac1 activation in comparison to cells expressing isoform 2. Isoform 2 expressing cells had decreased macropinocytic uptake, but demonstrated greater sensitivity to Rac1 activation. Moreover, more isoform 2 was localized within the cytoplasm in comparison to isoform 3, which was more associated with the plasma membrane. Activated Rac1 was found to specifically bind to a site in exon 10 of isoform 2 in vitro. Because of alternative mRNA splicing, exon 10 is absent from isoform 3, precluding similar binding of activated Rac1. Both isoforms, however, bound to inactive Rac1 through the same non-exon 10 site. Thus, Abi1 isoform 3-containing Wave 2 complex exhibited a differential binding to activated vs. inactive Rac1, whereas isoform 2-containing Wave 2 complex bound activated or inactive Rac1 comparably. CONCLUSION: Based on these observations, we postulate that Abi1 isoforms differentially regulate macropinocytosis as a consequence of their different relative affinities for activated Rac1 in Wave 2 complex. These findings also raise the possibility that isoform-specific roles occur in other Abi1 functions.

  18. EGFR soluble isoforms and their transcripts are expressed in meningiomas.

    Science.gov (United States)

    Guillaudeau, Angélique; Durand, Karine; Bessette, Barbara; Chaunavel, Alain; Pommepuy, Isabelle; Projetti, Fabrice; Robert, Sandrine; Caire, François; Rabinovitch-Chable, Hélène; Labrousse, François

    2012-01-01

    The EGFR (epidermal growth factor receptor) is involved in the oncogenesis of many tumors. In addition to the full-length EGFR (isoform a), normal and tumor cells produce soluble EGFR isoforms (sEGFR) that lack the intracellular domain. sEGFR isoforms b, c and d are encoded by EGFR variants 2 (v2), 3 (v3) and 4 (v4) mRNA resulting from gene alternative splicing. Accordingly, the results of EGFR protein expression analysis depend on the domain targeted by the antibodies. In meningiomas, EGFR expression investigations mainly focused on EGFR isoform a. sEGFR and EGFRvIII mutant, that encodes a constitutively active truncated receptor, have not been studied. In a 69 meningiomas series, protein expression was analyzed by immunohistochemistry using extracellular domain targeted antibody (ECD-Ab) and intracellular domain targeted antibody (ICD-Ab). EGFRv1 to v4 and EGFRvIII mRNAs were quantified by RT-PCR and EGFR amplification revealed by MLPA. Results were analyzed with respect to clinical data, tumor resection (Simpson grade), histological type, tumor grade, and patient outcome.Immunochemical staining was stronger with ECD-Ab than with ICD-Ab. Meningiomas expressed EGFRv1 to -v4 mRNAs but not EGFRvIII mutant. Intermediate or high ECD-Ab staining and high EGFRv1 to v4 mRNA levels were associated to a better progression free survival (PFS). PFS was also improved in women, when tumor resection was evaluated as Simpson 1 or 2, in grade I vs. grade II and III meningiomas and when Ki67 labeling index was lower than 10%. Our results suggest that, EGFR protein isoforms without ICD and their corresponding mRNA variants are expressed in meningiomas in addition to the whole isoform a. EGFRvIII was not expressed. High expression levels seem to be related to a better prognosis. These results indicate that the oncogenetic mechanisms involving the EGFR pathway in meningiomas could be different from other tumor types. PMID:22623992

  19. EGFR soluble isoforms and their transcripts are expressed in meningiomas.

    Directory of Open Access Journals (Sweden)

    Angélique Guillaudeau

    Full Text Available The EGFR (epidermal growth factor receptor is involved in the oncogenesis of many tumors. In addition to the full-length EGFR (isoform a, normal and tumor cells produce soluble EGFR isoforms (sEGFR that lack the intracellular domain. sEGFR isoforms b, c and d are encoded by EGFR variants 2 (v2, 3 (v3 and 4 (v4 mRNA resulting from gene alternative splicing. Accordingly, the results of EGFR protein expression analysis depend on the domain targeted by the antibodies. In meningiomas, EGFR expression investigations mainly focused on EGFR isoform a. sEGFR and EGFRvIII mutant, that encodes a constitutively active truncated receptor, have not been studied. In a 69 meningiomas series, protein expression was analyzed by immunohistochemistry using extracellular domain targeted antibody (ECD-Ab and intracellular domain targeted antibody (ICD-Ab. EGFRv1 to v4 and EGFRvIII mRNAs were quantified by RT-PCR and EGFR amplification revealed by MLPA. Results were analyzed with respect to clinical data, tumor resection (Simpson grade, histological type, tumor grade, and patient outcome.Immunochemical staining was stronger with ECD-Ab than with ICD-Ab. Meningiomas expressed EGFRv1 to -v4 mRNAs but not EGFRvIII mutant. Intermediate or high ECD-Ab staining and high EGFRv1 to v4 mRNA levels were associated to a better progression free survival (PFS. PFS was also improved in women, when tumor resection was evaluated as Simpson 1 or 2, in grade I vs. grade II and III meningiomas and when Ki67 labeling index was lower than 10%. Our results suggest that, EGFR protein isoforms without ICD and their corresponding mRNA variants are expressed in meningiomas in addition to the whole isoform a. EGFRvIII was not expressed. High expression levels seem to be related to a better prognosis. These results indicate that the oncogenetic mechanisms involving the EGFR pathway in meningiomas could be different from other tumor types.

  20. Differential regulation of renal phospholipase C isoforms by catecholamines.

    OpenAIRE

    Yu, P Y; Asico, L D; Eisner, G M; Jose, P A

    1995-01-01

    Dopamine and D1 agonists and NE all increase phosphatidyl inositol-specific phospholipase C (PLC) activity, but whereas dopamine produces a natriuresis, NE has an antinatriuretic effect. To determine if catecholamines differentially regulate the expression of PLC isoforms, we infused fenoldopam, a D1 agonist, or pramipexole, a D1/D2 agonist, intravenously or infused fenoldopam or NE into the renal artery of anesthetized rats. After 3-4 h of infusion, when the expected natriuresis (fenoldopam ...

  1. GABAB(1) receptor subunit isoforms differentially regulate stress resilience

    OpenAIRE

    O’Leary, Olivia F.; Felice, Daniela; Galimberti, Stefano; Savignac, Hélène M.; Bravo, Javier A.; Crowley, Tadhg; El Yacoubi, Malika; Vaugeois, Jean-Marie; Gassmann, Martin; Bettler, Bernhard; Dinan, Timothy G.; Cryan, John F.

    2014-01-01

    Stress can increase susceptibility to developing psychiatric disorders, including depression. Understanding the neurobiological mechanisms underlying stress resilience and susceptibility is key to identifying novel targets for the development of more effective treatments for stress-related psychiatric disorders. Here we show that specific isoforms of GABAB receptor subunits differentially regulate stress resilience. Specifically, GABAB(1a)−/− mice are more susceptible whereas GABAB(1b)−/− mic...

  2. Characterisation of CDKL5 Transcript Isoforms in Human and Mouse

    Science.gov (United States)

    Dando, Owen; Landsberger, Nicoletta; Kilstrup-Nielsen, Charlotte; Kind, Peter C.; Bailey, Mark E. S.; Cobb, Stuart R.

    2016-01-01

    Mutations in the X-linked Cyclin-Dependent Kinase-Like 5 gene (CDKL5) cause early onset infantile spasms and subsequent severe developmental delay in affected children. Deleterious mutations have been reported to occur throughout the CDKL5 coding region. Several studies point to a complex CDKL5 gene structure in terms of exon usage and transcript expression. Improvements in molecular diagnosis and more extensive research into the neurobiology of CDKL5 and pathophysiology of CDKL5 disorders necessitate an updated analysis of the gene. In this study, we have analysed human and mouse CDKL5 transcript patterns both bioinformatically and experimentally. We have characterised the predominant brain isoform of CDKL5, a 9.7 kb transcript comprised of 18 exons with a large 6.6 kb 3’-untranslated region (UTR), which we name hCDKL5_1. In addition we describe new exonic regions and a range of novel splice and UTR isoforms. This has enabled the description of an updated gene model in both species and a standardised nomenclature system for CDKL5 transcripts. Profiling revealed tissue- and brain development stage-specific differences in expression between transcript isoforms. These findings provide an essential backdrop for the diagnosis of CDKL5-related disorders, for investigations into the basic biology of this gene and its protein products, and for the rational design of gene-based and molecular therapies for these disorders. PMID:27315173

  3. Molecular mechanical differences between isoforms of contractile actin in the presence of isoforms of smooth muscle tropomyosin.

    OpenAIRE

    Lennart Hilbert; Genevieve Bates; Roman, Horia N.; Jenna L Blumenthal; Zitouni, Nedjma B.; Apolinary Sobieszek; Mackey, Michael C.; Anne-Marie Lauzon

    2013-01-01

    The proteins involved in smooth muscle's molecular contractile mechanism - the anti-parallel motion of actin and myosin filaments driven by myosin heads interacting with actin - are found as different isoforms. While their expression levels are altered in disease states, their relevance to the mechanical interaction of myosin with actin is not sufficiently understood. Here, we analyzed in vitro actin filament propulsion by smooth muscle myosin for [Formula: see text]-actin ([Formula: see text...

  4. Selective glucocorticoid receptor translational isoforms reveal glucocorticoid-induced apoptotic transcriptomes.

    Science.gov (United States)

    Wu, I; Shin, S C; Cao, Y; Bender, I K; Jafari, N; Feng, G; Lin, S; Cidlowski, J A; Schleimer, R P; Lu, N Z

    2013-01-01

    Induction of T-cell apoptosis contributes to the anti-inflammatory and antineoplastic benefits of glucocorticoids. The glucocorticoid receptor (GR) translational isoforms have distinct proapoptotic activities in osteosarcoma cells. Here we determined whether GR isoforms selectively induce apoptosis in Jurkat T lymphoblastic leukemia cells. Jurkat cells stably expressing individual GR isoforms were generated and treated with vehicle or dexamethasone (DEX). DEX induced apoptosis in cells expressing the GR-A, -B, or -C, but not the GR-D, isoform. cDNA microarray analyses of cells sensitive (GR-C3) and insensitive (GR-D3) to DEX revealed glucocorticoid-induced proapoptotic transcriptomes. Genes that were regulated by the proapoptotic GR-C3, but not by the GR-D3, isoform likely contributed to glucocorticoid-induced apoptosis. The identified genes include those that are directly involved in apoptosis and those that facilitate cell killing. Chromatin immunoprecipitation assays demonstrated that distinct chromatin modification abilities may underlie the distinct functions of GR isoforms. Interestingly, all GR isoforms, including the GR-D3 isoform, suppressed mitogen-stimulated cytokines. Furthermore, the GR-C isoforms were selectively upregulated in mitogen-activated primary T cells and DEX treatment induced GR-C target genes in activated T cells. Cell-specific expressions and functions of GR isoforms may help to explain the tissue- and individual-selective actions of glucocorticoids and may provide a basis for developing improved glucocorticoids. PMID:23303127

  5. Novel role of caspase-8 in the maintenance of epidermal regeneration and repair

    OpenAIRE

    Lee, Pedro

    2011-01-01

    Mammalian skin plays an essential role in protecting the body from environmental insults and as a result exhibits remarkable healing capabilities. Skin repair is characterized by the expression of three distinct but overlapping phases: inflammation, proliferation and remodeling. Successful restoration of tissue function after damage depends on the interactions among these phases. Despite the wealth of information on the wound healing process, little is known about the molecular mechanisms tha...

  6. Caspase-8 regulates TNF-alpha-induced epithelial necroptosis and terminal ileitis

    OpenAIRE

    Günther, Claudia; Martini, Eva; Wittkopf, Nadine; Amann, Kerstin; Weigmann, Benno; Neumann, Helmut; Waldner, Maximilian J.; Hedrick, Stephen M; Tenzer, Stefan; Neurath, Markus F; Becker, Christoph

    2011-01-01

    Dysfunction of the intestinal epithelium is believed to result in excessive translocation of commensal bacteria into the bowel wall that drives chronic mucosal inflammation in Crohn's disease; an incurable inflammatory bowel disease in humans characterized by inflammation of the terminal ileum 1 . Beside the physical barrier established by the tight contact of cells, specialized epithelial cells such as Paneth cells and goblet cells provide innate immune defence functions by secreting mucus a...

  7. Altered Alpha-Synuclein, Parkin, and Synphilin Isoform Levels in Multiple System Atrophy Brains

    DEFF Research Database (Denmark)

    Brudek, Tomasz; Winge, Kristian; Bredo Rasmussen, Nadja;

    2016-01-01

    -1 isoforms. In MSA brains, alpha-synuclein140 and alpha-synuclein112 isoform levels were significantly increased,whereas levels of the alpha-synuclein126 isoform were decreased in the substantia nigra, striatum, cerebellar cortex, and nucleus dentatus vs. CONTROLS: Moreover, in MSA cases, we showed...... increased levels of parkin isoforms lacking the N-terminal ubiquitin-like domain and an aggregation-prone synphiln-1A isoform that causes neuronal toxicity in MSA. In PD brains, Parkin transcript variant 3, 7 and 11 were significantly and specifically overexpressed in the striatum and cerebellar cortex......, together with synphilin-1A and 1C. The changes of isoform expression profiles in neurodegenerative diseases suggest alterations in the regulation of transcription and/or splicing events, leading to regional/cellular events that may be important for the highly increased aggregation of alpha-synuclein in the...

  8. PKC isoforms interact with and phosphorylate DNMT1

    Directory of Open Access Journals (Sweden)

    Pradhan Sriharsa

    2011-05-01

    Full Text Available Abstract Background DNA methyltransferase 1 (DNMT1 has been shown to be phosphorylated on multiple serine and threonine residues, based on cell type and physiological conditions. Although recent studies have suggested that protein kinase C (PKC may be involved, the individual contribution of PKC isoforms in their ability to phosphorylate DNMT1 remains unknown. The PKC family consists of at least 12 isoforms that possess distinct differences in structure, substrate requirement, expression and localization. Results Here we show that PKCα, βI, βII, δ, γ, η, ζ and μ preferentially phosphorylate the N-terminal domain of human DNMT1. No such phosphorylation of DNMT1 was observed with PKCε. Using PKCζ as a prototype model, we also found that PKC physically interacts with and phosphorylates DNMT1. In vitro phosphorylation assays conducted with recombinant fragments of DNMT1 showed that PKCζ preferentially phosphorylated the N-terminal region of DNMT1. The interaction of PKCζ with DNMT1 was confirmed by GST pull-down and co-immunoprecipitation experiments. Co-localization experiments by fluorescent microscopy further showed that endogenous PKCζ and DNMT1 were present in the same molecular complex. Endogenous PKCζ activity was also detected when DNMT1 was immunoprecipitated from HEK-293 cells. Overexpression of both PKCζ and DNMT1 in HEK-293 cells, but not of either alone, reduced the methylation status of genes distributed across the genome. Moreover, in vitro phosphorylation of DNMT1 by PKCζ reduced its methytransferase activity. Conclusions Our results indicate that phosphorylation of human DNMT1 by PKC is isoform-specific and provides the first evidence of cooperation between PKCζ and DNMT1 in the control of the DNA methylation patterns of the genome.

  9. Functional differences between L- and T-plastin isoforms

    OpenAIRE

    1994-01-01

    Fimbrins/plastins are a family of highly conserved actin-bundling proteins. They are present in all eukaryotic cells including yeast, but each isoform displays a remarkable tissue specificity. T-plastin is normally found in epithelial and mesenchymal cells while L-plastin is present in hematopoietic cells. However, L-plastin has been also found in tumor cells of non-hematopoietic origin (Lin, C.-S., R. H. Aebersold, S. B. Kent, M. Varma, and J. Leavitt. 1988. Mol. Cell. Biol. 8:4659-4668; Lin...

  10. The FU gene and its possible protein isoforms

    Directory of Open Access Journals (Sweden)

    Nöthen Markus M

    2004-07-01

    Full Text Available Abstract Background FU is the human homologue of the Drosophila gene fused whose product fused is a positive regulator of the transcription factor Cubitus interruptus (Ci. Thus, FU may act as a regulator of the human counterparts of Ci, the GLI transcription factors. Since Ci and GLI are targets of Hedgehog signaling in development and morphogenesis, it is expected that FU plays an important role in Sonic, Desert and/or Indian Hedgehog induced cellular signaling. Results The FU gene was identified on chromosome 2q35 at 217.56 Mb and its exon-intron organization determined. The human developmental disorder Syndactyly type 1 (SD1 maps to this region on chromosome 2 and the FU coding region was sequenced using genomic DNA from an affected individual in a linked family. While no FU mutations were found, three single nucleotide polymorphisms were identified. The expression pattern of FU was thoroughly investigated and all examined tissues express FU. It is also clear that different tissues express transcripts of different sizes and some tissues express more than one transcript. By means of nested PCR of specific regions in RT/PCR generated cDNA, it was possible to verify two alternative splicing events. This also suggests the existence of at least two additional protein isoforms besides the FU protein that has previously been described. This long FU and a much shorter isoform were compared for the ability to regulate GLI1 and GLI2. None of the FU isoforms showed any effects on GLI1 induced transcription but the long form can enhance GLI2 activity. Apparently FU did not have any effect on SUFU induced inhibition of GLI. Conclusions The FU gene and its genomic structure was identified. FU is a candidate gene for SD1, but we have not identified a pathogenic mutation in the FU coding region in a family with SD1. The sequence information and expression analyses show that transcripts of different sizes are expressed and subjected to alternative splicing

  11. GSK-3β phosphorylation of functionally distinct tau isoforms has differential, but mild effects

    Directory of Open Access Journals (Sweden)

    Gamblin T Chris

    2009-05-01

    Full Text Available Abstract Background Tau protein exists as six different isoforms that differ by the inclusion or exclusion of exons 2, 3 and 10. Exon 10 encodes a microtubule binding repeat, thereby resulting in three isoforms with three microtubule binding repeats (3R and three isoforms that have four microtubule binding repeats (4R. In normal adult brain, the relative amounts of 3R tau and 4R tau are approximately equal. These relative protein levels are preserved in Alzheimer's disease, although in other neurodegenerative tauopathies such as progressive supranuclear palsy, corticobasal degeneration and Pick's disease, the ratio of 3R:4R is frequently altered. Because tau isoforms are not equally involved in these diseases, it is possible that they either have inherently unique characteristics owing to their primary structures or that post-translational modification, such as phosphorylation, differentially affects their properties. Results We have determined the effects of phosphorylation by a kinase widely believed to be involved in neurodegenerative processes, glycogen synthase kinase-3β (GSK-3β, on the microtubule binding and inducer-initiated polymerization of these isoforms in vitro. We have found that each isoform has a unique microtubule binding and polymerization profile that is altered by GSK-3β. GSK-3β phosphorylation had differential effects on the isoforms although there were similarities between isoforms and the effects were generally mild. Conclusion These results indicate that tau phosphorylation by a single kinase can have isoform specific outcomes. The mild nature of these changes, however, makes it unlikely that differential effects of GSK-3β phosphorylation on the isoforms are causative in neurodegenerative disease. Instead, the inherent differences in the isoform interactions themselves and local conditions in the diseased cells are likely the major determinant of isoform involvement in various neurodegenerative disorders.

  12. Selective glucocorticoid receptor translational isoforms reveal glucocorticoid-induced apoptotic transcriptomes

    OpenAIRE

    Wu, I; Shin, S. C.; Cao, Y; Bender, I K; N Jafari; Feng, G.; Lin, S.; Cidlowski, J. A.; Schleimer, R. P.; Lu, N Z

    2013-01-01

    Induction of T-cell apoptosis contributes to the anti-inflammatory and antineoplastic benefits of glucocorticoids. The glucocorticoid receptor (GR) translational isoforms have distinct proapoptotic activities in osteosarcoma cells. Here we determined whether GR isoforms selectively induce apoptosis in Jurkat T lymphoblastic leukemia cells. Jurkat cells stably expressing individual GR isoforms were generated and treated with vehicle or dexamethasone (DEX). DEX induced apoptosis in cells expres...

  13. MetaDiff: differential isoform expression analysis using random-effects meta-regression

    OpenAIRE

    Jia, Cheng; Guan, Weihua; Yang, Amy; Xiao, Rui; Tang, W. H. Wilson; Moravec, Christine S.; Margulies, Kenneth B.; Cappola, Thomas P.; Li, Mingyao; Li, Chun

    2015-01-01

    Background RNA sequencing (RNA-Seq) allows an unbiased survey of the entire transcriptome in a high-throughput manner. A major application of RNA-Seq is to detect differential isoform expression across experimental conditions, which is of great biological interest due to its direct relevance to protein function and disease pathogenesis. Detection of differential isoform expression is challenging because of uncertainty in isoform expression estimation owing to ambiguous reads and variability i...

  14. Induction of Chemokine Expression by Adiponectin In Vitro is Isoform-Dependent

    OpenAIRE

    Song, Huijuan; Chan, James; Rovin, Brad H.

    2009-01-01

    Adiponectin is reported to have both pro- and anti-inflammatory effects. Because adiponectin circulates in isoforms of various sizes, and some responses to adiponectin are isoform-dependent, it was postulated that the pro-inflammatory effects of adiponectin may isoform-specific. To test this, peripheral blood mononuclear cells (PBMC), microvascular endothelial cells (MVEC), and human glomerular mesangial cells (HMC) were treated with high or low molecular weight (HMW, LMW) recombinant human a...

  15. IsoformEx: isoform level gene expression estimation using weighted non-negative least squares from mRNA-Seq data

    Directory of Open Access Journals (Sweden)

    Gupta Ravi

    2011-07-01

    Full Text Available Abstract Background mRNA-Seq technology has revolutionized the field of transcriptomics for identification and quantification of gene transcripts not only at gene level but also at isoform level. Estimating the expression levels of transcript isoforms from mRNA-Seq data is a challenging problem due to the presence of constitutive exons. Results We propose a novel algorithm (IsoformEx that employs weighted non-negative least squares estimation method to estimate the expression levels of transcript isoforms. Validations based on in silico simulation of mRNA-Seq and qRT-PCR experiments with real mRNA-Seq data showed that IsoformEx could accurately estimate transcript expression levels. In comparisons with published methods, the transcript expression levels estimated by IsoformEx showed higher correlation with known transcript expression levels from simulated mRNA-Seq data, and higher agreement with qRT-PCR measurements of specific transcripts for real mRNA-Seq data. Conclusions IsoformEx is a fast and accurate algorithm to estimate transcript expression levels and gene expression levels, which takes into account short exons and alternative exons with a weighting scheme. The software is available at http://bioinformatics.wistar.upenn.edu/isoformex.

  16. Proteomic Analysis of Cytokeratin Isoforms Uncovers Association with Survival in Lung Adenocarcinoma

    Directory of Open Access Journals (Sweden)

    Tarek G. Gharib

    2002-01-01

    Full Text Available Cytokeratins. (CK are intermediate filaments whose expression is often altered in epithelial cancer. Systematic identification of lung adenocarcinoma proteins using two-dimensional polyacrylamide gel electrophoresis and mass spectrometry has uncovered numerous CK isoforms. In this study, 93 lung adenocarcinomas. (64 stage I and 29 stage III and 10 uninvolved lung samples were quantitatively examined for protein expression. Fourteen of 21 isoforms of CK 7, 8, 18, 19 occurred at significantly higher levels. (P<.05 in tumors compared to uninvolved adjacent tissue. Specific isoforms of the four types of CK identified correlated with either clinical outcome or individual clinical-pathological parameters. All five of the CK7 isoforms associated with patient survival represented cleavage products. Two of five CK7 isoforms. (nos. 2165 and 2091, one of eight CK8 isoforms. (no. 439, one of three CK19 isoforms. (no. 1955 were associated with survival and significantly correlated to their mRNA levels, suggesting that transcription underlies overexpression of these CK isoforms. Our data indicate substantial heterogeneity among CK in lung adenocarcinomas resulting from posttranslational modifications, some of which correlated with patient survival and other clinical parameters. Therefore, specific isoforms of individual CK may have utility as diagnostic or predictive markers in lung adenocarcinomas.

  17. A Review of Metallothionein Isoforms and their Role in Pathophysiology

    Directory of Open Access Journals (Sweden)

    Senthil kumar M

    2011-05-01

    Full Text Available Abstract The Metallothionein (MT is a protein which has several interesting biological effects and has been demonstrated increase focus on the role of MT in various biological systems in the past three decades. The studies on the role of MT were limited with few areas like apoptosis and antioxidants in selected organs even fifty years after its discovery. Now acknowledge the exploration of various isoforms of MT such as MT-I, MT-II, MT-III and MT-IV and other isoforms in various biological systems. Strong evidence exists that MT modulates complex diseases and the immune system in the body but the primary function of MT still remains unknown. This review's main objective is to explore the capability to specifically manipulate MT levels in cells and in animals to provide answers regarding how MT could impact those complex disease scenarios. The experimental result mentioned in this review related among MT, zinc, cadmium, diabetic, heart disease, bone retardation, neuro toxicity, kidney dysfunction, cancer, and brain suggest novel method for exploration and contribute significantly to the growing scientist to research further in this field.

  18. Entropy-based model for miRNA isoform analysis.

    Directory of Open Access Journals (Sweden)

    Shengqin Wang

    Full Text Available MiRNAs have been widely studied due to their important post-transcriptional regulatory roles in gene expression. Many reports have demonstrated the evidence of miRNA isoform products (isomiRs in high-throughput small RNA sequencing data. However, the biological function involved in these molecules is still not well investigated. Here, we developed a Shannon entropy-based model to estimate isomiR expression profiles of high-throughput small RNA sequencing data extracted from miRBase webserver. By using the Kolmogorov-Smirnov statistical test (KS test, we demonstrated that the 5p and 3p miRNAs present more variants than the single arm miRNAs. We also found that the isomiR variant, except the 3' isomiR variant, is strongly correlated with Minimum Free Energy (MFE of pre-miRNA, suggesting the intrinsic feature of pre-miRNA should be one of the important factors for the miRNA regulation. The functional enrichment analysis showed that the miRNAs with high variation, particularly the 5' end variation, are enriched in a set of critical functions, supporting these molecules should not be randomly produced. Our results provide a probabilistic framework for miRNA isoforms analysis, and give functional insights into pre-miRNA processing.

  19. A New View of Ras Isoforms in Cancers.

    Science.gov (United States)

    Nussinov, Ruth; Tsai, Chung-Jung; Chakrabarti, Mayukh; Jang, Hyunbum

    2016-01-01

    Does small GTPase K-Ras4A have a single state or two states, one resembling K-Ras4B and the other N-Ras? A recent study of K-Ras4A made the remarkable observation that even in the absence of the palmitoyl, K-Ras4A can be active at the plasma membrane. Importantly, this suggests that K-Ras4A may exist in two distinct signaling states. In state 1, K-Ras4A is only farnesylated, like K-Ras4B; in state 2, farnesylated and palmitoylated, like N-Ras. The K-Ras4A hypervariable region sequence is positively charged, in between K-Ras4B and N-Ras. Taken together, this raises the possibility that the farnesylated but nonpalmitoylated state 1, like K-Ras4B, binds calmodulin and is associated with colorectal and other adenocarcinomas like lung cancer and pancreatic ductal adenocarcinoma. On the other hand, state 2 may be associated with melanoma and other cancers where N-Ras is a major contributor, such as acute myeloid leukemia. Importantly, H-Ras has two, singly and doubly, palmitoylated states that may also serve distinct functional roles. The multiple signaling states of palmitoylated Ras isoforms question the completeness of small GTPase Ras isoform statistics in different cancer types and call for reevaluation of concepts and protocols. They may also call for reconsideration of oncogenic Ras therapeutics. PMID:26659836

  20. Role of cysteines in mammalian VDAC isoforms' function.

    Science.gov (United States)

    De Pinto, Vito; Reina, Simona; Gupta, Ankit; Messina, Angela; Mahalakshmi, Radhakrishnan

    2016-08-01

    In this mini-review, we analyze the influence of cysteines in the structure and activity of mitochondrial outer membrane mammalian VDAC isoforms. The three VDAC isoforms show conserved sequences, similar structures and the same gene organization. The meaning of three proteins encoded in different chromosomes must thus be searched for subtle differences at the amino acid level. Among others, cysteine content is noticeable. In humans, VDAC1 has 2, VDAC2 has 9 and VDAC3 has 6 cysteines. Recent works have shown that, at variance from VDAC1, VDAC2 and VDAC3 exhibit cysteines predicted to protrude towards the intermembrane space, making them a preferred target for oxidation by ROS. Mass spectrometry in VDAC3 revealed that a disulfide bridge can be formed and other cysteine oxidations are also detectable. Both VDAC2 and VDAC3 cysteines were mutagenized to highlight their role in vitro and in complementation assays in Δporin1 yeast. Chemico-physical techniques revealed an important function of cysteines in the structural stabilization of the pore. In conclusion, the works available on VDAC cysteines support the notion that the three proteins are paralogs with a similar pore-function and slightly different, but important, ancillary biological functions. This article is part of a Special Issue entitled 'EBEC 2016: 19th European Bioenergetics Conference, Riva del Garda, Italy, July 2-6, 2016', edited by Prof. Paolo Bernardi. PMID:26947058

  1. Expression of phosphoinositide-specific phospholipase C isoforms in native endothelial cells.

    Directory of Open Access Journals (Sweden)

    Delphine M Béziau

    Full Text Available Phospholipase C (PLC comprises a superfamily of enzymes that play a key role in a wide array of intracellular signalling pathways, including protein kinase C and intracellular calcium. Thirteen different mammalian PLC isoforms have been identified and classified into 6 families (PLC-β, γ, δ, ε, ζ and η based on their biochemical properties. Although the expression of PLC isoforms is tissue-specific, concomitant expression of different PLC has been reported, suggesting that PLC family is involved in multiple cellular functions. Despite their critical role, the PLC isoforms expressed in native endothelial cells (ECs remains undetermined. A conventional PCR approach was initially used to elucidate the mRNA expression pattern of PLC isoforms in 3 distinct murine vascular beds: mesenteric (MA, pulmonary (PA and middle cerebral arteries (MCA. mRNA encoding for most PLC isoforms was detected in MA, MCA and PA with the exception of η2 and β2 (only expressed in PA, δ4 (only expressed in MCA, η1 (expressed in all but MA and ζ (not detected in any vascular beds tested. The endothelial-specific PLC expression was then sought in freshly isolated ECs. Interestingly, the PLC expression profile appears to differ across the investigated arterial beds. While mRNA for 8 of the 13 PLC isoforms was detected in ECs from MA, two additional PLC isoforms were detected in ECs from PA and MCA. Co-expression of multiple PLC isoforms in ECs suggests an elaborate network of signalling pathways: PLC isoforms may contribute to the complexity or diversity of signalling by their selective localization in cellular microdomains. However in situ immunofluorescence revealed a homogeneous distribution for all PLC isoforms probed (β3, γ2 and δ1 in intact endothelium. Although PLC isoforms play a crucial role in endothelial signal transduction, subcellular localization alone does not appear to be sufficient to determine the role of PLC in the signalling microdomains found

  2. Different phosphoinositide 3-kinase isoforms mediate carrageenan nociception and inflammation.

    Science.gov (United States)

    Pritchard, Rory A; Falk, Lovissa; Larsson, Mathilda; Leinders, Mathias; Sorkin, Linda S

    2016-01-01

    Phosphoinositide 3-kinases (PI3Ks) participate in signal transduction cascades that can directly activate and sensitize nociceptors and enhance pain transmission. They also play essential roles in chemotaxis and immune cell infiltration leading to inflammation. We wished to determine which PI3K isoforms were involved in each of these processes. Lightly anesthetized rats (isoflurane) were injected subcutaneously with carrageenan in their hind paws. This was preceded by a local injection of 1% DMSO vehicle or an isoform-specific antagonist to PI3K-α (compound 15-e), -β (TGX221), -δ (Cal-101), or -γ (AS252424). We measured changes in the mechanical pain threshold and spinal c-Fos expression (4 hours after injection) as indices of nociception. Paw volume, plasma extravasation (Evans blue, 0.3 hours after injection), and neutrophil (myeloperoxidase; 1 hour after injection) and macrophage (CD11b+; 4 hour after injection) infiltration into paw tissue were the measured inflammation endpoints. Only PI3K-γ antagonist before treatment reduced the carrageenan-induced pain behavior and spinal expression of c-Fos (P ≤ 0.01). In contrast, pretreatment with PI3K-α, -δ, and-γ antagonists reduced early indices of inflammation. Plasma extravasation PI3K-α (P ≤ 0.05), -δ (P ≤ 0.05), and -γ (P ≤ 0.01), early (0-2 hour) edema -α (P ≤ 0.05), -δ (P ≤ 0.001), and -γ (P ≤ 0.05), and neutrophil infiltration (all P ≤ 0.001) were all reduced compared to vehicle pretreatment. Later (2-4 hour), edema and macrophage infiltration (P ≤ 0.05) were reduced by only the PI3K-δ and -γ isoform antagonists, with the PI3K-δ antagonist having a greater effect on edema. PI3K-β antagonism was ineffective in all paradigms. These data indicate that pain and clinical inflammation are pharmacologically separable and may help to explain clinical conditions in which inflammation naturally wanes or goes into remission, but pain continues unabated. PMID:26313408

  3. Activation of antithrombin III isoforms by heparan sulphate glycosaminoglycans and other sulphated polysaccharides.

    Science.gov (United States)

    Carlson, T H; Kolman, M R; Piepkorn, M

    1995-07-01

    Antithrombin III occurs naturally as two functionally distinct molecular species that differ in glycosylation at Asn135. Whereas the predominant, glycosylated isoform has high affinity for heparin, a quantitatively minor isoform lacking glycosylation at that site displays relatively higher affinity for both heparins and heparinoids. We characterized the ability of various sulphated polysaccharides to potentiate the rates of thrombin inhibition by the isoforms. High-molecular-weight dextran sulphate was the most effective of those studied, increasing thrombin inhibition by the higher-affinity antithrombin III isoform up to five-fold more efficiently than did heparin fractions with low-affinity for antithrombin III. In addition, dextran sulphate activated the higher-affinity isoform as much as twelve times more effectively than it did the lower-affinity isoform. Pentosan polysulphate was up to three-fold, and some heparan sulphate fractions up to two-fold, more effective with the higher, compared with the lower affinity, isoform. Heparan sulphate preparations less effectively increased the rate of thrombin inhibition than did the other low-affinity polysaccharides. Structure-function studies indicated positive correlations between activity and both polymer length and anionic group density of low-affinity sulphated polysaccharides. The observed effects of the heparan sulphates on this anticoagulant pathway, although of low potency, are consistent with the hypotheses that these substances naturally regulate blood homeostasis in vascular tissues and that much of this function may be mediated by the higher-affinity antithrombin III isoform. PMID:8589216

  4. AN ENZYME LINKED IMMUNOSORBENT ASSAY FOR THE HO-1 ISOFORM OF HEME OXYGENASE

    Science.gov (United States)

    AN ENZYME LINKED IMMUNOSORBENT ASSAY FOR THE HO-1 ISOFORM OF HEME OXYGENASE Heme oxygenase (HO) occurs in biological tissues as two major isoforms HO-1 and HO-2. HO-1 is inducible by many treatments, particularly oxidative stress-related conditions such as depletion of gl...

  5. Development of isoform-specific sensors of polypeptide GalNAc-transferase activity

    DEFF Research Database (Denmark)

    Song, Lina; Bachert, Collin; Schjoldager, Katrine T; Clausen, Henrik; Linstedt, Adam D

    2014-01-01

    Humans express up to 20 isoforms of GalNAc-transferase (herein T1-T20) that localize to the Golgi apparatus and initiate O-glycosylation. Regulation of this enzyme family affects a vast array of proteins transiting the secretory pathway and diseases arise upon misregulation of specific isoforms...

  6. Activation of AMPK alpha and gamma-isoform complexes in the intact ischemic rat heart

    Science.gov (United States)

    AMP-activated protein kinase (AMPK) plays a key role in modulating cellular metabolic processes. AMPK, a serine-threonine kinase, is a heterotrimeric complex of catalytic alpha-subunits and regulatory beta- and gamma-subunits with multiple isoforms. Mutations in the cardiac gamma(2)-isoform have bee...

  7. Comprehensive analysis of tropomyosin isoforms in skeletal muscles by top-down proteomics.

    Science.gov (United States)

    Jin, Yutong; Peng, Ying; Lin, Ziqing; Chen, Yi-Chen; Wei, Liming; Hacker, Timothy A; Larsson, Lars; Ge, Ying

    2016-04-01

    Mammalian skeletal muscles are heterogeneous in nature and are capable of performing various functions. Tropomyosin (Tpm) is a major component of the thin filament in skeletal muscles and plays an important role in controlling muscle contraction and relaxation. Tpm is known to consist of multiple isoforms resulting from different encoding genes and alternative splicing, along with post-translational modifications. However, a systematic characterization of Tpm isoforms in skeletal muscles is still lacking. Therefore, we employed top-down mass spectrometry (MS) to identify and characterize Tpm isoforms present in different skeletal muscles from multiple species, including swine, rat, and human. Our study revealed that Tpm1.1 and Tpm2.2 are the two major Tpm isoforms in swine and rat skeletal muscles, whereas Tpm1.1, Tpm2.2, and Tpm3.12 are present in human skeletal muscles. Tandem MS was utilized to identify the sequences of the major Tpm isoforms. Furthermore, quantitative analysis revealed muscle-type specific differences in the abundance of un-modified and modified Tpm isoforms in rat and human skeletal muscles. This study represents the first systematic investigation of Tpm isoforms in skeletal muscles, which not only demonstrates the capabilities of top-down MS for the comprehensive characterization of skeletal myofilament proteins but also provides the basis for further studies on these Tpm isoforms in muscle-related diseases. PMID:27090236

  8. Molecular cloning and pharmacology of functionally distinct isoforms of the human histamine H(3) receptor

    DEFF Research Database (Denmark)

    Wellendorph, Petrine; Goodman, M W; Burstein, E S;

    2002-01-01

    The pharmacology of histamine H(3) receptors suggests the presence of distinct receptor isoforms or subtypes. We herein describe multiple, functionally distinct, alternatively spliced isoforms of the human H(3) receptor. Combinatorial splicing at three different sites creates at least six distinc...

  9. Roles of the troponin isoforms during indirect flight muscle development in Drosophila

    Indian Academy of Sciences (India)

    Salam Herojeet Singh; Prabodh Kumar; Nallur B. Ramachandra; Upendra Nongthomba

    2014-08-01

    Troponin proteins in cooperative interaction with tropomyosin are responsible for controlling the contraction of the striated muscles in response to changes in the intracellular calcium concentration. Contractility of the muscle is determined by the constituent protein isoforms, and the isoforms can switch over from one form to another depending on physiological demands and pathological conditions. In Drosophila, amajority of themyofibrillar proteins in the indirect flight muscles (IFMs) undergo post-transcriptional and post-translational isoform changes during pupal to adult metamorphosis to meet the high energy and mechanical demands of flight. Using a newly generated Gal4 strain (UH3-Gal4) which is expressed exclusively in the IFMs, during later stages of development, we have looked at the developmental and functional importance of each of the troponin subunits (troponin-I, troponin-T and troponin-C) and their isoforms. We show that all the troponin subunits are required for normal myofibril assembly and flight, except for the troponin-C isoform 1 (TnC1). Moreover, rescue experiments conducted with troponin-I embryonic isoform in the IFMs, where flies were rendered flightless, show developmental and functional differences of TnI isoforms and importance of maintaining the right isoform.

  10. Translational control of C/EBPalpha and C/EBPbeta isoform expression

    NARCIS (Netherlands)

    Calkhoven, C F; Müller, C; Leutz, A

    2000-01-01

    Transcription factors derived from CCAAT/enhancer binding protein (C/EBP)alpha and C/EBPbeta genes control differentiation and proliferation in a number of cell types. Various C/EBP isoforms arise from unique C/EBPbeta and C/EBPalpha mRNAs by differential initiation of translation. These isoforms re

  11. Exo70 Isoform Switching upon Epithelial-Mesenchymal Transition Mediates Cancer Cell Invasion

    Science.gov (United States)

    Lu, Hezhe; Liu, Jianglan; Liu, Shujing; Zeng, Jingwen; Ding, Deqiang; Carstens, Russ P.; Cong, Yusheng; Xu, Xiaowei; Guo, Wei

    2014-01-01

    Summary Epithelial-mesenchymal transition (EMT) is an important developmental process hijacked by cancer cells for their dissemination. Here we show that Exo70, a component of the exocyst complex, undergoes isoform switching mediated by ESRP1, a pre-mRNA splicing factor that regulates EMT. Expression of the epithelial isoform of Exo70 affects the levels of key EMT transcriptional regulators such as Snail and ZEB2, and is sufficient to drive the transition to epithelial phenotypes. Differential Exo70 isoforms expression in human tumors correlates with cancer progression, and increased expression of the epithelial isoform of Exo70 inhibits tumor metastasis in mice. At the molecular level, the mesenchymal but not the epithelial isoform of Exo70 interacts with the Arp2/3 complex and stimulates actin polymerization for tumor invasion. Our findings provide a mechanism by which the exocyst function and actin dynamics are modulated for EMT and tumor invasion. PMID:24331928

  12. Pharmacological targeting of PI3K isoforms as a therapeutic strategy in chronic lymphocytic leukaemia

    Science.gov (United States)

    Blunt, Matthew D.; Steele, Andrew J.

    2015-01-01

    PI3Kδ inhibitors such as idelalisib are providing improved therapeutic options for the treatment of chronic lymphocytic leukaemia (CLL). However under certain conditions, inhibition of a single PI3K isoform can be compensated by the other PI3K isoforms, therefore PI3K inhibitors which target multiple PI3K isoforms may provide greater efficacy. The development of compounds targeting multiple PI3K isoforms (α, β, δ, and γ) in CLL cells, in vitro, resulted in sustained inhibition of BCR signalling but with enhanced cytotoxicity and the potential for improve clinical responses. This review summarises the progress of PI3K inhibitor development and describes the rationale and potential for targeting multiple PI3K isoforms. PMID:26500849

  13. Pharmacological targeting of PI3K isoforms as a therapeutic strategy in chronic lymphocytic leukaemia

    Directory of Open Access Journals (Sweden)

    Matthew D. Blunt

    2015-01-01

    Full Text Available PI3Kδ inhibitors such as idelalisib are providing improved therapeutic options for the treatment of chronic lymphocytic leukaemia (CLL. However under certain conditions, inhibition of a single PI3K isoform can be compensated by the other PI3K isoforms, therefore PI3K inhibitors which target multiple PI3K isoforms may provide greater efficacy. The development of compounds targeting multiple PI3K isoforms (α, β, δ, and γ in CLL cells, in vitro, resulted in sustained inhibition of BCR signalling but with enhanced cytotoxicity and the potential for improve clinical responses. This review summarises the progress of PI3K inhibitor development and describes the rationale and potential for targeting multiple PI3K isoforms.

  14. Isoform-specific phosphorylation-dependent regulation of connexin hemichannels

    DEFF Research Database (Denmark)

    Alstrøm, Jette Skov; Hansen, Daniel Bloch; Nielsen, Morten Schak;

    2015-01-01

    Connexins form gap junction channels made up of two connexons (hemichannels) from adjacent cells. Unopposed hemichannels may open toward the extracellular space upon stimulation by, e.g., removal of divalent cations from the extracellular solution and allow isoform-specific transmembrane flux of...... fluorescent dyes and physiologically relevant molecules, such as ATP and ions. Connexin (Cx)43 and Cx30 are the major astrocytic connexins. Protein kinase C (PKC) regulates Cx43 in its cell-cell gap junction configuration and may also act to keep Cx43 hemichannels closed. In contrast, the regulation of Cx30...... hemichannels by PKC is unexplored. To determine phosphorylation-dependent regulation of Cx30 and Cx43 hemichannels, these were heterologously expressed in Xenopus laevis oocytes and opened with divalent cation-free solution. Inhibition of PKC activity did not affect hemichannel opening of either connexin. PKC...

  15. Troponin T isoform expression is modulated during Atlantic Halibut metamorphosis

    Directory of Open Access Journals (Sweden)

    Llewellyn Lynda

    2007-06-01

    Full Text Available Abstract Background Flatfish metamorphosis is a thyroid hormone (TH driven process which leads to a dramatic change from a symmetrical larva to an asymmetrical juvenile. The effect of THs on muscle and in particular muscle sarcomer protein genes is largely unexplored in fish. The change in Troponin T (TnT, a pivotal protein in the assembly of skeletal muscles sarcomeres and a modulator of calcium driven muscle contraction, during flatfish metamophosis is studied. Results In the present study five cDNAs for halibut TnT genes were cloned; three were splice variants arising from a single fast TnT (fTnT gene; a fourth encoded a novel teleost specific fTnT-like cDNA (AfTnT expressed exclusively in slow muscle and the fifth encoded the teleost specific sTnT2. THs modified the expression of halibut fTnT isoforms which changed from predominantly basic to acidic isoforms during natural and T4 induced metamorphosis. In contrast, expression of red muscle specific genes, AfTnT and sTnT2, did not change during natural metamorphosis or after T4 treatment. Prior to and after metamorphosis no change in the dorso-ventral symmetry or temporal-spatial expression pattern of TnT genes and muscle fibre organization occurred in halibut musculature. Conclusion Muscle organisation in halibut remains symmetrical even after metamorphosis suggesting TH driven changes are associated with molecular adaptations. We hypothesize that species specific differences in TnT gene expression in teleosts underlies different larval muscle developmental programs which better adapts them to the specific ecological constraints.

  16. p53 isoforms regulate astrocyte-mediated neuroprotection and neurodegeneration.

    Science.gov (United States)

    Turnquist, C; Horikawa, I; Foran, E; Major, E O; Vojtesek, B; Lane, D P; Lu, X; Harris, B T; Harris, C C

    2016-09-01

    Bidirectional interactions between astrocytes and neurons have physiological roles in the central nervous system and an altered state or dysfunction of such interactions may be associated with neurodegenerative diseases, such as Alzheimer's disease (AD) and amyotrophic lateral sclerosis (ALS). Astrocytes exert structural, metabolic and functional effects on neurons, which can be either neurotoxic or neuroprotective. Their neurotoxic effect is mediated via the senescence-associated secretory phenotype (SASP) involving pro-inflammatory cytokines (e.g., IL-6), while their neuroprotective effect is attributed to neurotrophic growth factors (e.g., NGF). We here demonstrate that the p53 isoforms Δ133p53 and p53β are expressed in astrocytes and regulate their toxic and protective effects on neurons. Primary human astrocytes undergoing cellular senescence upon serial passaging in vitro showed diminished expression of Δ133p53 and increased p53β, which were attributed to the autophagic degradation and the SRSF3-mediated alternative RNA splicing, respectively. Early-passage astrocytes with Δ133p53 knockdown or p53β overexpression were induced to show SASP and to exert neurotoxicity in co-culture with neurons. Restored expression of Δ133p53 in near-senescent, otherwise neurotoxic astrocytes conferred them with neuroprotective activity through repression of SASP and induction of neurotrophic growth factors. Brain tissues from AD and ALS patients possessed increased numbers of senescent astrocytes and, like senescent astrocytes in vitro, showed decreased Δ133p53 and increased p53β expression, supporting that our in vitro findings recapitulate in vivo pathology of these neurodegenerative diseases. Our finding that Δ133p53 enhances the neuroprotective function of aged and senescent astrocytes suggests that the p53 isoforms and their regulatory mechanisms are potential targets for therapeutic intervention in neurodegenerative diseases. PMID:27104929

  17. Locomotion in Lymphocytes is Altered by Differential PKC Isoform Expression

    Science.gov (United States)

    Sundaresan, A.; Risin, D.; Pellis, N. R.

    1999-01-01

    Lymphocyte locomotion is critical for proper elicitation of the immune response. Locomotion of immune cells via the interstitium is essential for optimal immune function during wound healing, inflammation and infection. There are conditions which alter lymphocyte locomotion and one of them is spaceflight. Lymphocyte locomotion is severely inhibited in true spaceflight (true microgravity) and in rotating wall vessel culture (modeled microgravity). When lymphocytes are activated prior to culture in modeled microgravity, locomotion is not inhibited and the levels are comparable to those of static cultured lymphocytes. When a phorbol ester (PMA) is used in modeled microgravity, lymphocyte locomotion is restored by 87%. This occurs regardless if PMA is added after culture in the rotating wall vessel or during culture. Inhibition of DNA synthesis also does not alter restoration of lymphocyte locomotion by PMA. PMA is a direct activator of (protein kinase C) PKC . When a calcium ionophore, ionomycin is used it does not possess any restorative properties towards locomotion either alone or collectively with PMA. Since PMA brings about restoration without help from calcium ionophores (ionomycin), it is infer-red that calcium independent PKC isoforms are involved. Changes were perceived in the protein levels of PKC 6 where levels of the protein were downregulated at 24,72 and 96 hours in untreated rotated cultures (modeled microgravity) compared to untreated static (1g) cultures. At 48 hours there is an increase in the levels of PKC & in the same experimental set up. Studies on transcriptional and translational patterns of calcium independent isoforms of PKC such as 8 and E are presented in this study.

  18. Characterization of ductal and lobular breast carcinomas using novel prolactin receptor isoform specific antibodies

    International Nuclear Information System (INIS)

    Prolactin is a polypeptide hormone responsible for proliferation and differentiation of the mammary gland. More recently, prolactin's role in mammary carcinogenesis has been studied with greater interest. Studies from our laboratory and from others have demonstrated that three specific isoforms of the prolactin receptor (PRLR) are expressed in both normal and cancerous breast cells and tissues. Until now, reliable isoform specific antibodies have been lacking. We have prepared and characterized polyclonal antibodies against each of the human PRLR isoforms that can effectively be used to characterize human breast cancers. Rabbits were immunized with synthetic peptides of isoform unique regions and immune sera affinity purified prior to validation by Western blot and immunohistochemical analyses. Sections of ductal and lobular carcinomas were stained with each affinity purified isoform specific antibody to determine expression patterns in breast cancer subclasses. We show that the rabbit antibodies have high titer and could specifically recognize each isoform of PRLR. Differences in PRLR isoform expression levels were observed and quantified using histosections from xenografts of established human breast cancer cells lines, and ductal and lobular carcinoma human biopsy specimens. In addition, these results were verified by real-time PCR with isoform specific primers. While nearly all tumors contained LF and SF1b, the majority (76%) of ductal carcinoma biopsies expressed SF1a while the majority of lobular carcinomas lacked SF1a staining (72%) and 27% had only low levels of expression. Differences in the receptor isoform expression profiles may be critical to understanding the role of PRL in mammary tumorigenesis. Since these antibodies are specifically directed against each PRLR isoform, they are valuable tools for the evaluation of breast cancer PRLR content and have potential clinical importance in treatment of this disease by providing new reagents to study

  19. VEGF-A isoforms program differential VEGFR2 signal transduction, trafficking and proteolysis

    Directory of Open Access Journals (Sweden)

    Gareth W. Fearnley

    2016-05-01

    Full Text Available Vascular endothelial growth factor A (VEGF-A binding to the receptor tyrosine kinase VEGFR2 triggers multiple signal transduction pathways, which regulate endothelial cell responses that control vascular development. Multiple isoforms of VEGF-A can elicit differential signal transduction and endothelial responses. However, it is unclear how such cellular responses are controlled by isoform-specific VEGF-A–VEGFR2 complexes. Increasingly, there is the realization that the membrane trafficking of receptor–ligand complexes influences signal transduction and protein turnover. By building on these concepts, our study shows for the first time that three different VEGF-A isoforms (VEGF-A165, VEGF-A121 and VEGF-A145 promote distinct patterns of VEGFR2 endocytosis for delivery into early endosomes. This differential VEGFR2 endocytosis and trafficking is linked to VEGF-A isoform-specific signal transduction events. Disruption of clathrin-dependent endocytosis blocked VEGF-A isoform-specific VEGFR2 activation, signal transduction and caused substantial depletion in membrane-bound VEGFR1 and VEGFR2 levels. Furthermore, such VEGF-A isoforms promoted differential patterns of VEGFR2 ubiquitylation, proteolysis and terminal degradation. Our study now provides novel insights into how different VEGF-A isoforms can bind the same receptor tyrosine kinase and elicit diverse cellular outcomes.

  20. Androgen receptor isoforms in human prostatic cancer tissue and LNCaP cell line

    Institute of Scientific and Technical Information of China (English)

    Shu-Jie XIA; Xiao-Da TANG; Qing-Zheng MA

    2001-01-01

    Aim: To investigate the androgen receptor (AR) isoform expressions in human prostatic cancer tissue and LNCaP cell line. Methods: With high resolution isoelectric focusing (IEF) method we demonstrated the different expressions of AR isoforms in human prostatic cancer tissues and LNCaP cell line. Results: Data were obtained from three prostatic cancer specimens and the LNCaP cell line. Three types of AR isoforms were detected with pI values at 6.5,6.0, and 5.3. For the 3 prostatic cancer specimens, 1 sample showed all the three types of AR isoforms, the second specimen expressed at 6.5 and 6.0, and the third failed to show any type of isoforms. The LNCaP cell line expressed all the three AR isoforms. Binding of 3H-dihydrotestosterone (3H-DHT) to these three isoforms was inhibited by the addition ofl00-fold excess of DHT or testosterone, while not by progesterone, oestradiol and diethylstilboestrol. Conclusion: The expression of AR isofonns is different in different prostate cancer tissues, which may be related to the difference in the effect of anti-androgen therapy in different patients.

  1. Dysregulation of miRNA isoform level at 5' end in Alzheimer's disease.

    Science.gov (United States)

    Wang, Shengqin; Xu, Yuming; Li, Musheng; Tu, Jing; Lu, Zuhong

    2016-06-15

    Alzheimer's disease (AD) is the most common form of dementia, whose mechanism is still not yet fully understood. A miRNA-based signature method, commonly according to the changes of expression levels, is widely used for AD analysis in previous studies. Recently, miRNA isoforms called as isomiR variants, which is considered to play important biological roles, have been demonstrated as the applications of high throughput sequencing platforms. Here, we presented an entropy-based model to detect the miRNA isoform level at the 5' end, and found many miRNAs with significant changes of isoform levels between the early stage and the late stage of AD by the application of this model to the public data. The statistical significance of the overlap between isoform-level changed miRNAs and AD related miRNAs extracted from HMDD2 supports that these miRNA isoforms are not degradation products. Based on the most common isomiR seed analysis of isoform-level changed AD related miRNAs, the predicted targets are also found to be enriched for genes involved in transcriptional regulation and the nervous system. After comparing with the expression level based method, we detected that changes of 5' isoform levels are more stable than those of expression levels for AD related miRNA detecting. PMID:26899870

  2. Quarternary structure and enzymological properties of the different hormone-sensitive lipase (HSL isoforms.

    Directory of Open Access Journals (Sweden)

    Christian Krintel

    Full Text Available BACKGROUND: Hormone-sensitive lipase (HSL is a key enzyme in the mobilization of energy in the form of fatty acids from intracellular stores of neutral lipids. The enzyme has been shown to exist in different isoforms with different molecular masses (84 kDa, 89 kDa and 117 kDa expressed in a tissue-dependent manner, where the predominant 84 kDa form in adipocytes is the most extensively studied. METHODOLOGY/PRINCIPAL FINDINGS: In this study we employed negative stain electron microscopy (EM to analyze the quarternary structure of the different HSL isoforms. The results show that all three isoforms adopt a head-to-head homodimeric organization, where each monomer contains two structural domains. We also used enzymatic assays to show that despite the variation in the size of the N-terminal domain all three isoforms exhibit similar enzymological properties with regard to psychrotolerance and protein kinase A (PKA-mediated phosphorylation and activation. CONCLUSIONS/SIGNIFICANCE: We present the first data on the quaternary structure and domain organization of the three HSL isoforms. We conclude that despite large differences in the size of the N-terminal, non-catalytic domain all three HSL isoforms exhibit the same three-dimensional architecture. Furthermore, the three HSL isoforms are very similar with regard to two unique enzymological characteristics of HSL, i.e., cold adaptation and PKA-mediated activation.

  3. The isolation of parvalbumin isoforms from the tail muscle of the American alligator (Alligator mississipiensis).

    Science.gov (United States)

    Laney, E L; Shabanowitz, J; King, G; Hunt, D F; Nelson, D J

    1997-04-01

    Multiple parvalbumin isoforms have been detected in the tail (skeletal) muscle of the American alligator (Alligator mississipiensis). One of these isoforms (APV-1) has been highly purified and partially characterized. Protein purification involved mainly gel filtration and anion exchange chromatography, and characterization included gel electrophoresis, amino acid composition analysis, metal ion analysis, MALDI-TOF and ESI mass spectrometry, ultraviolet and fluorescence spectroscopy, and one- and two-dimensional 500 MHz proton NMR spectroscopy. The alligator isoforms are rich in phenylalanine and deficient in the other aromatic residues as is typical for parvalbumins. In fact, the one highly purified isoform that forms the basis of this study has only phenyl-alanine as an aromatic residue. Ion exchange chromatography further indicates that this isoform has a relatively high isoelectric point (pl approximately 5.0), indicating that it is an alpha-lineage parvalbumin. This alligator parvalbumin isoform is unusual in that it has an atypically high Ca2+ content (almost 3.0 mole of Ca2+ per mole of protein) following purification, a fact supported by terbium fluorescence titration experiments. Preliminary comparative analysis of the highly purified alligator parvalbumin isoform (in the Ca2-loaded state) by two-dimensional 1H-NMR (2D 1H TOCSY and 2D 1H NOESY) indicates that there is considerable similarity in structure between the alligator protein and a homologous protein obtained from the silver hake (a saltwater fish species). PMID:9076974

  4. Isoform-specific upregulation of palladin in human and murine pancreas tumors.

    Directory of Open Access Journals (Sweden)

    Silvia M Goicoechea

    Full Text Available Pancreatic ductal adenocarcinoma (PDA is a lethal disease with a characteristic pattern of early metastasis, which is driving a search for biomarkers that can be used to detect the cancer at an early stage. Recently, the actin-associated protein palladin was identified as a candidate biomarker when it was shown that palladin is mutated in a rare inherited form of PDA, and overexpressed in many sporadic pancreas tumors and premalignant precursors. In this study, we analyzed the expression of palladin isoforms in murine and human PDA and explored palladin's potential use in diagnosing PDA. We performed immunohistochemistry and immunoblot analyses on patient samples and tumor-derived cells using an isoform-selective monoclonal antibody and a pan-palladin polyclonal antibody. Immunoblot and real-time quantitative reverse transcription-PCR were used to quantify palladin mRNA levels in human samples. We show that there are two major palladin isoforms expressed in pancreas: 65 and 85-90 kDa. The 65 kDa isoform is expressed in both normal and neoplastic ductal epithelial cells. The 85-90 kDa palladin isoform is highly overexpressed in tumor-associated fibroblasts (TAFs in both primary and metastatic tumors compared to normal pancreas, in samples obtained from either human patients or genetically engineered mice. In tumor-derived cultured cells, expression of palladin isoforms follows cell-type specific patterns, with the 85-90 kDa isoform in TAFs, and the 65 kDa isoform predominating in normal and neoplastic epithelial cells. These results suggest that upregulation of 85-90 kDa palladin isoform may play a role in the establishment of the TAF phenotype, and thus in the formation of a desmoplastic tumor microenvironment. Thus, palladin may have a potential use in the early diagnosis of PDA and may have much broader significance in understanding metastatic behavior.

  5. Learning-dependent gene expression of CREB1 isoforms in the molluscan brain

    Directory of Open Access Journals (Sweden)

    Hisayo Sadamoto

    2010-05-01

    Full Text Available Cyclic AMP-responsive element binding protein1 (CREB1 has multiple functions in gene regulation. Various studies have reported that CREB1-dependent gene induction is necessary for memory formation and long-lasting behavioral changes in both vertebrates and invertebrates. In the present study, we characterized Lymnaea CREB1 (LymCREB1 mRNA isoforms of spliced variants in the central nervous system (CNS of the pond snail Lymnaea stagnalis. Among these spliced variants, the three isoforms that code a whole LymCREB1 protein are considered to be the activators for gene regulation. The other four isoforms, which code truncated LymCREB1 proteins with no kinase inducible domain, are the repressors. For a better understanding of the possible roles of different LymCREB1 isoforms, the expression level of these isoform mRNAs was investigated by a real-time quantitative RT-PCR method. Further, we examined the changes in gene expression for all the isoforms in the CNS after conditioned taste aversion (CTA learning or backward conditioning as a control. The results showed that CTA learning increased LymCREB1 gene expression, but it did not change the activator/repressor ratio. Our findings showed that the repressor isoforms, as well as the activator ones, are expressed in large amounts in the CNS, and the gene expression of CREB1 isoforms appeared to be specific for the given stimulus. This was the first quantitative analysis of the expression patterns of CREB1 isoforms at the mRNA level and their association with learning behavior.

  6. Myosin isoform fiber type and fiber size in the tail of the Virginia opossum (Didelphis virginiana).

    Science.gov (United States)

    Hazimihalis, P J; Gorvet, M A; Butcher, M T

    2013-01-01

    Muscle fiber type is a well studied property in limb muscles, however, much less is understood about myosin heavy chain (MHC) isoform expression in caudal muscles of mammalian tails. Didelphid marsupials are an interesting lineage in this context as all species have prehensile tails, but show a range of tail-function depending on either their arboreal or terrestrial locomotor habits. Differences in prehensility suggest that MHC isoform fiber types may also be different, in that terrestrial opossums may have a large distribution of oxidative fibers for object carrying tasks instead of faster, glycolytic fiber types expected in mammals with long tails. To test this hypothesis, MHC isoform fiber type and their regional distribution (proximal/transitional/distal) were determined in the tail of the Virginia opossum (Didelphis virginiana). Fiber types were determined by a combination of myosin-ATPase histochemistry, immunohistochemistry, and SDS-PAGE. Results indicate a predominance of the fast MHC-2A and -2X isoforms in each region of the tail. The presence of two fast isoforms, in addition to the slow MHC-1 isoform, was confirmed by SDS-PAGE analysis. The overall MHC isoform fiber type distribution for the tail was: 25% MHC-1, 71% MHC-2A/X hybrid, and 4% MHC-1/2A hybrid. Oxidative MHC-2A/X isoform fibers were found to be relatively large in cross-section compared to slow, oxidative MHC-1 and MHC-1/2A hybrid fibers. A large percentage of fast MHC-2A/X hybrids fibers may be suggestive of an evolutionary transition in MHC isoform distribution (fast-to-slow fiber type) in the tail musculature of an opossum with primarily a terrestrial locomotor habit and adaptive tail-function. PMID:23152195

  7. PML isoforms in response to arsenic: high-resolution analysis of PML body structure and degradation.

    Science.gov (United States)

    Hands, Katherine J; Cuchet-Lourenco, Delphine; Everett, Roger D; Hay, Ronald T

    2014-01-15

    Arsenic is a clinically effective treatment for acute promyelocytic leukaemia (APL) in which the promyelocytic leukaemia (PML) protein is fused to retinoic receptor alpha (RARα). PML-RARα is degraded by the proteasome by a SUMO-dependent, ubiquitin-mediated pathway in response to arsenic treatment, curing the disease. Six major PML isoforms are expressed as a result of alternative splicing, each of which encodes a unique C-terminal region. Using a system in which only a single EYFP-linked PML isoform is expressed, we demonstrate that PMLI, PMLII and PMLVI accumulate in the cytoplasm following arsenic treatment, whereas PMLIII, PMLIV and PMLV do not. 3D structured illumination was used to obtain super-resolution images of PML bodies, revealing spherical shells of PML along with associated SUMO. Arsenic treatment results in dramatic isoform-specific changes to PML body ultrastructure. After extended arsenic treatment most PML isoforms are degraded, leaving SUMO at the core of the nuclear bodies. A high-content imaging assay identifies PMLV as the isoform most readily degraded following arsenic treatment, and PMLIV as relatively resistant to degradation. Immunoprecipitation analysis demonstrates that all PML isoforms are modified by SUMO and ubiquitin after arsenic treatment, and by using siRNA, we demonstrate that arsenic-induced degradation of all PML isoforms is dependent on the ubiquitin E3 ligase RNF4. Intriguingly, depletion of RNF4 results in marked accumulation of PMLV, suggesting that this isoform is an optimal substrate for RNF4. Thus the variable C-terminal domain influences the rate and location of degradation of PML isoforms following arsenic treatment. PMID:24190887

  8. A Synaptotagmin Isoform Switch during the Development of an Identified CNS Synapse.

    Science.gov (United States)

    Kochubey, Olexiy; Babai, Norbert; Schneggenburger, Ralf

    2016-06-01

    Various Synaptotagmin (Syt) isoform genes are found in mammals, but it is unknown whether Syts can function redundantly in a given nerve terminal, or whether isoforms can be switched during the development of a nerve terminal. Here, we investigated the possibility of a developmental Syt isoform switch using the calyx of Held as a model synapse. At mature calyx synapses, fast Ca(2+)-driven transmitter release depended entirely on Syt2, but the release phenotype of Syt2 knockout (KO) mice was weaker at immature calyces, and absent at pre-calyceal synapses early postnatally. Instead, conditional genetic inactivation shows that Syt1 mediates fast release at pre-calyceal synapses, as well as a fast release component resistant to Syt2 deletion in immature calyces. This demonstrates a developmental Syt1-Syt2 isoform switch at an identified synapse, a mechanism that could fine-tune the speed, reliability, and plasticity of transmitter release at fast releasing CNS synapses. PMID:27210552

  9. Isoform-selective regulation of glycogen phosphorylase by energy deprivation and phosphorylation in astrocytes

    DEFF Research Database (Denmark)

    Müller, Margit S; Pedersen, Sofie E; Walls, Anne B;

    2015-01-01

    Glycogen phosphorylase (GP) is activated to degrade glycogen in response to different stimuli, to support both the astrocyte's own metabolic demand and the metabolic needs of neurons. The regulatory mechanism allowing such a glycogenolytic response to distinct triggers remains incompletely...... understood. In the present study, we used siRNA-mediated differential knockdown of the two isoforms of GP expressed in astrocytes, muscle isoform (GPMM), and brain isoform (GPBB), to analyze isoform-specific regulatory characteristics in a cellular setting. Subsequently, we tested the response of each...... determination of glycogen content showing an increase in glycogen levels following knockdown of either GPMM or GPBB. NE triggered glycogenolysis within 15 min in control cells and after GPBB knockdown. However, astrocytes in which expression of GPMM had been silenced showed a delay in response to NE, with...

  10. Network-Based Isoform Quantification with RNA-Seq Data for Cancer Transcriptome Analysis.

    Science.gov (United States)

    Zhang, Wei; Chang, Jae-Woong; Lin, Lilong; Minn, Kay; Wu, Baolin; Chien, Jeremy; Yong, Jeongsik; Zheng, Hui; Kuang, Rui

    2015-12-01

    High-throughput mRNA sequencing (RNA-Seq) is widely used for transcript quantification of gene isoforms. Since RNA-Seq data alone is often not sufficient to accurately identify the read origins from the isoforms for quantification, we propose to explore protein domain-domain interactions as prior knowledge for integrative analysis with RNA-Seq data. We introduce a Network-based method for RNA-Seq-based Transcript Quantification (Net-RSTQ) to integrate protein domain-domain interaction network with short read alignments for transcript abundance estimation. Based on our observation that the abundances of the neighboring isoforms by domain-domain interactions in the network are positively correlated, Net-RSTQ models the expression of the neighboring transcripts as Dirichlet priors on the likelihood of the observed read alignments against the transcripts in one gene. The transcript abundances of all the genes are then jointly estimated with alternating optimization of multiple EM problems. In simulation Net-RSTQ effectively improved isoform transcript quantifications when isoform co-expressions correlate with their interactions. qRT-PCR results on 25 multi-isoform genes in a stem cell line, an ovarian cancer cell line, and a breast cancer cell line also showed that Net-RSTQ estimated more consistent isoform proportions with RNA-Seq data. In the experiments on the RNA-Seq data in The Cancer Genome Atlas (TCGA), the transcript abundances estimated by Net-RSTQ are more informative for patient sample classification of ovarian cancer, breast cancer and lung cancer. All experimental results collectively support that Net-RSTQ is a promising approach for isoform quantification. Net-RSTQ toolbox is available at http://compbio.cs.umn.edu/Net-RSTQ/. PMID:26699225

  11. Expression of Two Novel Alternatively Spliced COL2A1 Isoforms During Chondrocyte Differentiation

    OpenAIRE

    McAlinden, Audrey; Johnstone, Brian; Kollar, John; Kazmi, Najam; Hering, Thomas M.

    2007-01-01

    Alternative splicing of the type II procollagen gene (COL2A1) is developmentally-regulated during chondrogenesis. Type IIA procollagen (+ exon 2) is synthesized by chondroprogenitor cells while type IIB procollagen (- exon 2) is synthesized by differentiated chondrocytes. Here, we report expression of two additional alternatively spliced COL2A1 isoforms during chondrocyte differentiation of bone marrow derived mesenchymal stem cells (MSCs). One isoform, named IIC, contains only the first 34 n...

  12. Myosin heavy-chain isoforms in the flight and leg muscles of hummingbirds and zebra finches

    OpenAIRE

    Velten, Brandy P.; Welch, Kenneth C.

    2014-01-01

    Myosin heavy chain (MHC) isoform complement is intimately related to a muscle's contractile properties, yet relatively little is known about avian MHC isoforms or how they may vary with fiber type and/or the contractile properties of a muscle. The rapid shortening of muscles necessary to power flight at the high wingbeat frequencies of ruby-throated hummingbirds and zebra finches (25–60 Hz), along with the varied morphology and use of the hummingbird hindlimb, provides a unique opportunity to...

  13. Sodium pump isoform specificity for the digitalis-like factor isolated from human peritoneal dialysate.

    Science.gov (United States)

    Tao, Q F; Hollenberg, N K; Price, D A; Graves, S W

    1997-03-01

    We have isolated a labile, specific sodium pump inhibitor or digitalis-like factor from the peritoneal dialysate of volume-expanded renal failure patients whose levels correlated closely with volume status and blood pressure. This study characterizes the inhibitory profile of this agent compared with that of ouabain against the three alpha-isoforms of the sodium pump. We prepared microsomal Na,K-ATPase from rat tissues representing the highest proportion of one of the alpha-isoforms. Both Northern and Western blot analyses confirmed that kidney had predominantly the alpha1-isoform, skeletal muscle the alpha2-isoform, and fetal brain the alpha3-isoform. Ouabain (5 x 10(-6) mol/L) produced little inhibition of kidney Na,K-ATPase (3.4+/-2.0%) but significant inhibition of skeletal muscle (37.2+/-3.7%, P<.001) and fetal brain (38.8+/-3.5%, P<.001) activity. In contrast, the labile digitalis-like factor, causing comparable inhibition of fetal brain Na,K-ATPase activity (33.3+/-4.7%), produced markedly greater inhibition of kidney (42.5+/-5.6%, P<.001) and moderately greater inhibition of skeletal muscle pump activity (57.7+/-6.3%, P<.05). In addition, the labile digitalis-like factor produced a marked concentration-dependent inhibition of the alpha2- and alpha3-isoforms (r=.79, P=.00005). Experiments combining the labile digitalis-like factor and ouabain confirmed that digitalis-like factor, unlike ouabain, was an effective inhibitor of all three isoforms in rat, in particular alpha2. The different pattern of isoform sensitivity displayed by the labile digitalis-like factor and ouabain further differentiates the two agents and raises some interesting possibilities about the functional implications of the endogenous factor. PMID:9052901

  14. Opposing effects of fructokinase C and A isoforms on fructose-induced metabolic syndrome in mice

    OpenAIRE

    Ishimoto, Takuji; Lanaspa, Miguel A.; MyPhuong T Le; Garcia, Gabriela E.; Diggle, Christine P; MacLean, Paul S.; Jackman, Matthew R.; Asipu, Aruna; Roncal-Jimenez, Carlos A.; Kosugi, Tomoki; Rivard, Christopher J.; Maruyama, Shoichi; Rodriguez-Iturbe, Bernardo; Sánchez-Lozada, Laura G.; Bonthron, David T.

    2012-01-01

    Fructose intake from added sugars correlates with the epidemic rise in obesity, metabolic syndrome, and nonalcoholic fatty liver disease. Fructose intake also causes features of metabolic syndrome in laboratory animals and humans. The first enzyme in fructose metabolism is fructokinase, which exists as two isoforms, A and C. Here we show that fructose-induced metabolic syndrome is prevented in mice lacking both isoforms but is exacerbated in mice lacking fructokinase A. Fructokinase C is expr...

  15. Genomic organization and the tissue distribution of alternatively spliced isoforms of the mouse Spatial gene

    Directory of Open Access Journals (Sweden)

    Mattei Marie-Geneviève

    2004-07-01

    Full Text Available Abstract Background The stromal component of the thymic microenvironment is critical for T lymphocyte generation. Thymocyte differentiation involves a cascade of coordinated stromal genes controlling thymocyte survival, lineage commitment and selection. The "Stromal Protein Associated with Thymii And Lymph-node" (Spatial gene encodes a putative transcription factor which may be involved in T-cell development. In the testis, the Spatial gene is also expressed by round spermatids during spermatogenesis. Results The Spatial gene maps to the B3-B4 region of murine chromosome 10 corresponding to the human syntenic region 10q22.1. The mouse Spatial genomic DNA is organised into 10 exons and is alternatively spliced to generate two short isoforms (Spatial-α and -γ and two other long isoforms (Spatial-δ and -ε comprising 5 additional exons on the 3' site. Here, we report the cloning of a new short isoform, Spatial-β, which differs from other isoforms by an additional alternative exon of 69 bases. This new exon encodes an interesting proline-rich signature that could confer to the 34 kDa Spatial-β protein a particular function. By quantitative TaqMan RT-PCR, we have shown that the short isoforms are highly expressed in the thymus while the long isoforms are highly expressed in the testis. We further examined the inter-species conservation of Spatial between several mammals and identified that the protein which is rich in proline and positive amino acids, is highly conserved. Conclusions The Spatial gene generates at least five alternative spliced variants: three short isoforms (Spatial-α, -β and -γ highly expressed in the thymus and two long isoforms (Spatial-δ and -ε highly expressed in the testis. These alternative spliced variants could have a tissue specific function.

  16. Recombinant erythropoietin in humans has a prolonged effect on circulating erythropoietin isoform distribution.

    Directory of Open Access Journals (Sweden)

    Niels Jacob Aachmann-Andersen

    Full Text Available The membrane-assisted isoform immunoassay (MAIIA quantitates erythropoietin (EPO isoforms as percentages of migrated isoforms (PMI. We evaluated the effect of recombinant human EPO (rhEPO on the distribution of EPO isoforms in plasma in a randomized, placebo-controlled, double-blinded, cross-over study. 16 healthy subjects received either low-dose Epoetin beta (5000 IU on days 1, 3, 5, 7, 9, 11 and 13; high-dose Epoetin beta (30.000 IU on days 1, 2 and 3 and placebo on days 5, 7, 9, 11 and 13; or placebo on all days. PMI on days 4, 11 and 25 was determined by interaction of N-acetyl glucosamine with the glycosylation dependent desorption of EPO isoforms. At day 25, plasma-EPO in both rhEPO groups had returned to values not different from the placebo group. PMI with placebo, reflecting the endogenous EPO isoforms, averaged 82.5 (10.3 % (mean (SD. High-dose Epoetin beta decreased PMI on days 4 and 11 to 31.0 (4.2% (p<0.00001 and 45.2 (7.3% (p<0.00001. Low-dose Epoetin beta decreased PMI on days 4 and 11 to 46.0 (12.8% (p<0.00001 and 46.1 (10.4% (p<0.00001. In both rhEPO groups, PMI on day 25 was still decreased (high-dose Epoetin beta: 72.9 (19.4% (p=0.029; low-dose Epoetin beta: 73.1 (17.8% (p=0.039. In conclusion, Epoetin beta leaves a footprint in the plasma-EPO isoform pattern. MAIIA can detect changes in EPO isoform distribution up til at least three weeks after administration of Epoetin beta even though the total EPO concentration has returned to normal.

  17. Expression of mdr isoforms in mice during estrous cycle and under hormone stimulation

    OpenAIRE

    Marion Schiengold; Lavínia Schwantes; Ribeiro, Maria F; Nívia Lothhammer; Gonzalez, Tatiana P.; Jose Artur Bogo Chies; Nardi, Nance B

    2006-01-01

    The multidrug resistance (MDR) phenotype is associated with the expression of P-glycoprotein (Pgp), coded by the multigenic mdr family. Mice present the isoforms mdr1 and mdr3, which are responsible for multidrug resistance, and mdr2, that is involved in the transport of phospholipids. mdr1 expression has more recently been associated also with the secretion of steroid hormones. This work presents an RT-PCR analysis of the expression of mdr isoforms, in several organs of mice during different...

  18. HIF1α isoforms in benign and malignant prostate tissue and their correlation to neuroendocrine differentiation

    International Nuclear Information System (INIS)

    Neuroendocrine (NE) differentiation in prostate cancer has been correlated with a poor prognosis and hormone refractory disease. In a previous report, we demonstrated the presence of immunoreactive cytoplasmic hypoxia inducible factor 1α (HIF1α), in both benign and malignant NE prostate cells. HIF1α and HIF1β are two subunits of HIF1, a transcription factor important for angiogenesis. The aim of this study was to elucidate whether the cytoplasmic stabilization of HIF1α in androgen independent NE differentiated prostate cancer is due to the presence of certain HIF1α isoforms. We studied the HIF1α isoforms present in 8 cases of benign prostate hyperplasia (BPH) and 43 cases of prostate cancer with and without NE differentiation using RT-PCR, sequencing analysis, immunohistochemistry and in situ hybridization. We identified multiple isoforms in both benign and malignant prostate tissues. One of these isoforms, HIF1α1.2, which was previously reported to be testis specific, was found in 86% of NE-differentiated prostate tumors, 92% of HIF1α immunoreactive prostate tumors and 100% of cases of benign prostate hyperplasia. Immunohistochemistry and in situ hybridization results showed that this isoform corresponds to the cytoplasmic HIF1α present in androgen-independent NE cells of benign and malignant prostate tissue and co-localizes with immunoreactive cytoplasmic HIF1β. Our results indicate that the cytoplasmic stabilization of HIF1α in NE-differentiated cells in benign and malignant prostate tissue is due to presence of an HIF1α isoform, HIF1α1.2. Co-localization of this isoform with HIF1β indicates that the HIF1α1.2 isoform might sequester HIF1β in the cytoplasm

  19. Differential and Conditional Activation of PKC-Isoforms Dictates Cardiac Adaptation during Physiological to Pathological Hypertrophy

    OpenAIRE

    Shaon Naskar; Kaberi Datta; Arkadeep Mitra; Kanchan Pathak; Ritwik Datta; Trisha Bansal; Sagartirtha Sarkar

    2014-01-01

    A cardiac hypertrophy is defined as an increase in heart mass which may either be beneficial (physiological hypertrophy) or detrimental (pathological hypertrophy). This study was undertaken to establish the role of different protein kinase-C (PKC) isoforms in the regulation of cardiac adaptation during two types of cardiac hypertrophy. Phosphorylation of specific PKC-isoforms and expression of their downstream proteins were studied during physiological and pathological hypertrophy in 24 week ...

  20. Progesterone receptor isoform A may regulate the effects of neoadjuvant aglepristone in canine mammary carcinoma

    OpenAIRE

    Guil-Luna, Silvia; Stenvang, Jan; Brünner, Nils; De Andrés, Francisco Javier; Rollón, Eva; Domingo, Víctor; Sánchez-Céspedes, Raquel; Millán, Yolanda; Mulas, Juana Martín de las

    2014-01-01

    Background Progesterone receptors play a key role in the development of canine mammary tumours, and recent research has focussed on their possible value as therapeutic targets using antiprogestins. Cloning and sequencing of the progesterone receptor gene has shown that the receptor has two isoforms, A and B, transcribed from a single gene. Experimental studies in human breast cancer suggest that the differential expression of progesterone receptor isoforms has implications for hormone therapy...

  1. Thermal Denaturation and Aggregation of Myosin Subfragment 1 Isoforms with Different Essential Light Chains

    OpenAIRE

    Zubov, Eugene O.; Nikolaeva, Olga P.; Kurganov, Boris I.; Dmitrii I. Levitsky; Markov, Denis I.

    2010-01-01

    We compared thermally induced denaturation and aggregation of two isoforms of the isolated myosin head (myosin subfragment 1, S1) containing different “essential” (or “alkali”) light chains, A1 or A2. We applied differential scanning calorimetry (DSC) to investigate the domain structure of these two S1 isoforms. For this purpose, a special calorimetric approach was developed to analyze the DSC profiles of irreversibly denaturing multidomain proteins. Using this approach, we revealed two calor...

  2. Differential Contributions of Nonmuscle Myosin II Isoforms and Functional Domains to Stress Fiber Mechanics

    OpenAIRE

    Ching-Wei Chang; Sanjay Kumar

    2015-01-01

    While is widely acknowledged that nonmuscle myosin II (NMMII) enables stress fibers (SFs) to generate traction forces against the extracellular matrix, little is known about how specific NMMII isoforms and functional domains contribute to SF mechanics. Here we combine biophotonic and genetic approaches to address these open questions. First, we suppress the NMMII isoforms MIIA and MIIB and apply femtosecond laser nanosurgery to ablate and investigate the viscoelastic retraction of individual ...

  3. Electrophoretic Mobility of Cardiac Myosin Heavy Chain Isoforms Revisited: Application of MALDI TOF/TOF Analysis

    Czech Academy of Sciences Publication Activity Database

    Arnoštová, P.; Jedelsky, P. L.; Soukup, Tomáš; Žurmanová, J.

    2011-01-01

    Roč. 2011, - (2011), e634253. ISSN 1110-7243 R&D Projects: GA AV ČR IAAX01110901; GA ČR(CZ) GA304/08/0256 Institutional research plan: CEZ:AV0Z50110509 Keywords : cardiac MyHC isoforms * MyHC isoform mobility * effect of thyroid hormones * mass spectrometry * SDS-PAGE and western blot Subject RIV: ED - Physiology Impact factor: 2.436, year: 2011

  4. Kinetics of local and systemic isoforms of serum amyloid A in bovine mastitic milk

    DEFF Research Database (Denmark)

    Jacobsen, Stine; Niewold, T.A.; Kornalijnslijper, E.;

    2005-01-01

    The aim of the present study was to characterise the serum amyloid A (SAA) response to intramammary inoculation of Escherichia coli and to examine the distribution of hepatically and extrahepatically pruduced SAA isoforms in plasma and milk fra cows with mastitis.......The aim of the present study was to characterise the serum amyloid A (SAA) response to intramammary inoculation of Escherichia coli and to examine the distribution of hepatically and extrahepatically pruduced SAA isoforms in plasma and milk fra cows with mastitis....

  5. A novel FADS1 isoform potentiates FADS2-mediated production of eicosanoid precursor fatty acids

    OpenAIRE

    Park, Woo Jung; Kothapalli, Kumar S. D.; Reardon, Holly T; Lawrence, Peter; Qian, Shu-Bing; Brenna, J. Thomas

    2012-01-01

    The fatty acid desaturase (FADS) genes code for the rate-limiting enzymes required for the biosynthesis of long-chain polyunsaturated fatty acids (LCPUFA). Here we report discovery and function of a novel FADS1 splice variant. FADS1 alternative transcript 1 (FADS1AT1) enhances desaturation of FADS2, leading to increased production of eicosanoid precursors, the first case of an isoform modulating the enzymatic activity encoded by another gene. Multiple protein isoforms were detected in primate...

  6. Molecular modeling study on tunnel behavior in different histone deacetylase isoforms.

    Directory of Open Access Journals (Sweden)

    Sundarapandian Thangapandian

    Full Text Available Histone deacetylases (HDACs have emerged as effective therapeutic targets in the treatment of various diseases including cancers as these enzymes directly involved in the epigenetic regulation of genes. However the development of isoform-selective HDAC inhibitors has been a challenge till date since all HDAC enzymes possess conserved tunnel-like active site. In this study, using molecular dynamics simulation we have analyzed the behavior of tunnels present in HDAC8, 10, and 11 enzymes of class I, II, and IV, respectively. We have identified the equivalent tunnel forming amino acids in these three isoforms and found that they are very much conserved with subtle differences to be utilized in selective inhibitor development. One amino acid, methionine of HDAC8, among six tunnel forming residues is different in isoforms of other classes (glutamic acid (E in HDAC10 and leucine (L in HDAC 11 based on which mutations were introduced in HDAC11, the less studied HDAC isoform, to observe the effects of this change. The HDAC8-like (L268M mutation in the tunnel forming residues has almost maintained the deep and narrow tunnel as present in HDAC8 whereas HDAC10-like (L268E mutation has changed the tunnel wider and shallow as observed in HDAC10. These results explained the importance of the single change in the tunnel formation in different isoforms. The observations from this study can be utilized in the development of isoform-selective HDAC inhibitors.

  7. Recombinant erythropoietin in humans has a prolonged effect on circulating erythropoietin isoform distribution

    DEFF Research Database (Denmark)

    Aachmann-Andersen, Niels Jacob; Just Christensen, Søren; Lisbjerg, Kristian;

    2014-01-01

    The membrane-assisted isoform immunoassay (MAIIA) quantitates erythropoietin (EPO) isoforms as percentages of migrated isoforms (PMI). We evaluated the effect of recombinant human EPO (rhEPO) on the distribution of EPO isoforms in plasma in a randomized, placebo-controlled, double-blinded, cross......-over study. 16 healthy subjects received either low-dose Epoetin beta (5000 IU on days 1, 3, 5, 7, 9, 11 and 13); high-dose Epoetin beta (30.000 IU on days 1, 2 and 3 and placebo on days 5, 7, 9, 11 and 13); or placebo on all days. PMI on days 4, 11 and 25 was determined by interaction of N......-acetyl glucosamine with the glycosylation dependent desorption of EPO isoforms. At day 25, plasma-EPO in both rhEPO groups had returned to values not different from the placebo group. PMI with placebo, reflecting the endogenous EPO isoforms, averaged 82.5 (10.3) % (mean (SD)). High-dose Epoetin beta decreased PMI on...

  8. Distribution of tropomyosin isoforms in different types of single fibers isolated from bovine skeletal muscles.

    Science.gov (United States)

    Oe, M; Ojima, K; Nakajima, I; Chikuni, K; Shibata, M; Muroya, S

    2016-08-01

    To clarify the relationship between myosin heavy chain (MyHC) isoforms and tropomyosin (TPM) isoforms in single fibers, 64 single fibers were isolated from each of bovine three muscles (masseter, semispinalis and semitendinosus). mRNA expressions of MyHC and TPM isoforms were analyzed by real-time PCR. All single fibers from the masseter expressed MyHC-slow. The fibers from the semispinalis expressed both MyHC-slow and 2a. The fibers from the semitendinosus expressed MyHC-slow, 2a and 2x. TPM-1 and TPM-2 were co-expressed in 2a and 2x type fibers, and TPM-2 and TPM-3 were co-expressed in slow type fibers. The expression pattern of TPM isoforms in each fiber type was similar between fibers isolated from different muscles. These results suggest that TPM-1 and TPM-3 isoforms correspond to the function of 2a or 2x type fibers and slow type fibers, respectively, with TPM-2 in common. Furthermore, the patterns of MyHC and TPM isoform combinations did not vary among single fibers isolated from the individual muscles examined. PMID:27105153

  9. Role of acyl carrier protein isoforms in plant lipid metabolism: Progress report

    Energy Technology Data Exchange (ETDEWEB)

    Ohlrogge, J.B.

    1989-01-01

    Previous research from my lab has revealed that several higher plant species have multiple isoforms of acyl carrier protein (ACP) and therefore this trait appears highly conserved among higher plants. This level of conservation suggests that the existence of ACP isoforms is not merely the results of neutral gene duplications. We have developed techniques to examine a wider range of species. Acyl carrier proteins can be labelled very specifically and to high specific activity using H-palmitate and the E. coli enzyme acyl-ACP synthetase. Isoforms were then resolved by western blotting and native PAGE of H-palmitate labelled ACP's. Multiple isoforms of ACP were observed the leaf tissue of the monocots Avena sativa and Hordeum vulgare and dicots including Arabidopsis thallina, Cuphea wrightii, and Brassica napus. Lower vascular plants including the cycad, Dioon edule, Ginkgo biloba, the gymnosperm Pinus, the fern Anernia phyllitidis and Psilotum nudum, the most primitive known extant vascular plant, were also found to have multiple ACP isoforms as were the nonvascular liverwort, Marchantia and moss, Polytrichum. Therefore, the development of ACP isoforms occurred early in evolution. However, the uniellular alge Chlamydomonas and Dunaliella and the photosynthetic cyanobacteria Synechocystis and Agmnellum have only a single elecrophotetic form of ACP. Thus, multiple forms of ACP do not occur in all photosynthetic organisms but may be associated with multicellular plants.

  10. Expression of mdr isoforms in mice during estrous cycle and under hormone stimulation

    Directory of Open Access Journals (Sweden)

    Marion Schiengold

    2006-01-01

    Full Text Available The multidrug resistance (MDR phenotype is associated with the expression of P-glycoprotein (Pgp, coded by the multigenic mdr family. Mice present the isoforms mdr1 and mdr3, which are responsible for multidrug resistance, and mdr2, that is involved in the transport of phospholipids. mdr1 expression has more recently been associated also with the secretion of steroid hormones. This work presents an RT-PCR analysis of the expression of mdr isoforms, in several organs of mice during different phases of the estrous cycle. Additionally, females were ovariectomized, submitted to different hormone treatments, and their uterus was analyzed for the expression of mdr isoforms. The results show that in the adrenal gland and ovaries mdr1 is the main isoform during proestrus, and that progesterone or a combination of progesterone and estrogen induce the expression of all mdr isoforms in the uterus of ovariectomized females. We suggest that the functions of mdr1 and mdr3 are overlapping, that mdr3 may be the more efficient isoform in the detoxification function, and that mdr1 may be more closely related to the secretion of steroid hormones.

  11. Molecular characterization of human thyroid hormone receptor β isoform 4.

    Science.gov (United States)

    Moriyama, Kenji; Yamamoto, Hiroyuki; Futawaka, Kumi; Atake, Asami; Kasahara, Masato; Tagami, Tetsuya

    2016-01-01

    Thyroid hormone exerts a pleiotropic effect on development, differentiation, and metabolism through thyroid hormone receptor (TR). A novel thyroid hormone receptor β isoform (TRβ4) was cloned using PCR from a human pituitary cDNA library as a template. We report here the characterization of TRβ4 from a molecular basis. Temporal expression of TRβ4 during the fetal period is abundant in the brain and kidney, comparable with the adult pattern. Western blot analysis revealed that TRs are ubiquitination labile proteins, while TRβ1 is potentially stable. TRβ1, peroxisome proliferator-activated receptors (PPAR), and vitamin D receptor (VDR), which belong to class II transcription factors that function via the formation of heterodimeric complexes with retinoid X receptor (RXR), were suppressed by TRβ4 in a dose-dependent manner. Thus, TRβ4 exhibits ligand-independent transcriptional silencing, possibly as a substitute for dimerized RXR. In this study, TRβ1 and TRβ4 transcripts were detected in several cell lines. Quantitative RT-PCR assay showed that the expression of TRβ4 in human embryonic carcinoma cells of the testis was suppressed by sex hormone in a reciprocal manner to TRβ1. In contrast, TRβ4 was expressed under a high dose of triiodothyronine (T3) in a reciprocal manner to TRβ1. Finally, in transiently transfected NIH-3T3 cells, green fluorescence protein (GFP)-tagged TRβ4 was mostly nuclear in both the absence and the presence of T3. By mutating defined regions of both TRβs, we found that both TRβ1 and TRβ4 had altered nuclear/cytoplasmic distribution as compared with wild-type, and different to T3 and the nuclear receptor corepressor (NCoR). Thus, site-specific DNA binding is not essential for maintaining TRβs within the nucleus. PMID:26513165

  12. Hyphenated techniques for the characterization and quantification of metallothionein isoforms

    Energy Technology Data Exchange (ETDEWEB)

    Prange, Andreas; Schaumloeffel, Dirk [GKSS Research Center, Institute for Coastal Research/Physical and Chemical Analysis, Max-Planck-Strasse, 21502 Geesthacht (Germany)

    2002-07-01

    Recent developments in the coupling of highly selective separation techniques such as capillary electrophoresis (CE) and high-performance liquid chromatography (HPLC) to element-specific and molecule-specific detectors, such as inductively-coupled plasma mass spectrometry (ICP-MS) and electrospray ionization-tandem mass spectrometry (ESI-MS/MS) for the characterization and quantification of metallothioneins (MTs) are critically reviewed and discussed. This review gives an update based on the literature over the last five years. The coupling of CE to ICP-MS is especially highlighted. As a result of progress in new interface technologies for CE-ICP-MS, research topics presented in the literature are changing from ''the characterization of interfaces by metallothioneins'' to the ''characterization of metallothioneins by CE-ICP-MS''. New applications of CE-ICP-MS to the analysis of MTs in real samples are summarized. The potential of the on-line isotope dilution technique for the quantification of MTs and for the determination of the stoichiometric composition of metalloprotein complexes is discussed. Furthermore, a selection of relevant papers dealing with HPLC-ICP-MS for MT analysis are summarized and compared to those dealing with CE-ICP-MS. In particular, the use of size-exclusion (SE)-HPLC as a preliminary separation step for metallothioneins in real samples prior to further chromatographic or electrophoretic separations is considered. Additionally, the application of electrospray ionisation-tandem mass spectrometry (ESI-MS/MS) for the identification of metallothionein isoforms following electrophoretic or chromatographic separation is discussed. (orig.)

  13. Expression of 14-3-3 protein isoforms in mouse oocytes, eggs and ovarian follicular development

    Directory of Open Access Journals (Sweden)

    De Santanu

    2012-01-01

    Full Text Available Abstract Background The 14-3-3 (YWHA proteins are a highly conserved, ubiquitously expressed family of proteins. Seven mammalian isoforms of 14-3-3 are known (β, γ, ε, ζ, η, τ and, σ. These proteins associate with many intracellular proteins involved in a variety of cellular processes including regulation of the cell cycle, metabolism and protein trafficking. We are particularly interested in the role of 14-3-3 in meiosis in mammalian eggs and the role 14-3-3 proteins may play in ovarian function. Therefore, we examined the expression of 14-3-3 proteins in mouse oocyte and egg extracts by Western blotting after polyacrylamide gel electrophoresis, viewed fixed cells by indirect immunofluorescence, and examined mouse ovarian cells by immunohistochemical staining to study the expression of the different 14-3-3 isoforms. Results We have determined that all of the mammalian 14-3-3 isoforms are expressed in mouse eggs and ovarian follicular cells including oocytes. Immunofluorescence confocal microscopy of isolated oocytes and eggs confirmed the presence of all of the isoforms with characteristic differences in some of their intracellular localizations. For example, some isoforms (β, ε, γ, and ζ are expressed more prominently in peripheral cytoplasm compared to the germinal vesicles in oocytes, but are uniformly dispersed within eggs. On the other hand, 14-3-3η is diffusely dispersed in the oocyte, but attains a uniform punctate distribution in the egg with marked accumulation in the region of the meiotic spindle apparatus. Immunohistochemical staining detected all isoforms within ovarian follicles, with some similarities as well as notable differences in relative amounts, localizations and patterns of expression in multiple cell types at various stages of follicular development. Conclusions We found that mouse oocytes, eggs and follicular cells within the ovary express all seven isoforms of the 14-3-3 protein. Examination of the

  14. Transferrin and Its Isoforms from Normal Human Serum Revealed by Several Analytical Techniques

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Transferrin(TF) and its isoforms have been widely reported via various analytical techniques, including a noticeable increased number of isoforms with low content of sialic acid(asialo-, monosialo-, and disialo-transferrin) and asialo-TF as well as disialo-TF, with one or several oligosaccharides released in human serum transferrin(hTf). Here,hTf has been purified by native gradient polyacrylamide gel electrophoresis(PAGENG) before use. The hTf extracted with the electron-transfer approach showed a single subunit band(77.1 Da) in the SDS-PAGE gel, but it exhibited two bands in the native and denatured isoelectric focusing(IEF) gels, namely, hTf-2Fe3+ and apo-hTf, without finding any other transferrin isoforms. A reversed phase HPLC(RP-HPLC) equipped with a C18 column effectively separated hTf and its polymers and combined off-line techniques, including peptide mass fingerprinting(PMF), matrix-assisted laser desorption/ionization time-of-flight mass spectrometry(MALDI-TOF-MS) and database search, and identified the high homology among hTf, apo-hTf, and their isoforms. Moreover, the elution solution consisting of acetonitrile and formic acid could easily denature both hTf and apo-hTf to form various isoforms during separation with HPLC, indicating that chemical factors lead to the formation of various isoforms in transferrin, artificially, during extraction and separation.The authors claimed that only two transferrin isoforms existed in the NHS, namely, hTf-2Fe3+ and apo-hTf, which could be employed in biomarkers, to distinguish the healthy population from many disease sufferers, such as,carbohydrate-deficient transferrin(CDT).

  15. Modeled microgravity-induced protein kinase C isoform expression in human lymphocytes

    Science.gov (United States)

    Sundaresan, A.; Risin, D.; Pellis, N. R.

    2004-01-01

    In long-term space travel, the crew is exposed to microgravity and radiation that invoke potential hazards to the immune system. T cell activation is a critical step in the immune response. Receptor-mediated signaling is inhibited in both microgravity and modeled microgravity (MMG) as reflected by diminished DNA synthesis in peripheral blood lymphocytes and their locomotion through gelled type I collagen. Direct activation of protein kinase C (PKC) bypassing cell surface events using the phorbol ester PMA rescues MMG-inhibited lymphocyte activation and locomotion, whereas the calcium ionophore ionomycin had no rescue effect. Thus calcium-independent PKC isoforms may be affected in MMG-induced locomotion inhibition and rescue. Both calcium-dependent isoforms and calcium-independent PKC isoforms were investigated to assess their expression in lymphocytes in 1 g and MMG culture. Human lymphocytes were cultured and harvested at 24, 48, 72, and 96 h, and serial samples were assessed for locomotion by using type I collagen and expression of PKC isoforms. Expression of PKC-alpha, -delta, and -epsilon was assessed by RT-PCR, flow cytometry, and immunoblotting. Results indicated that PKC isoforms delta and epsilon were downregulated by >50% at the transcriptional and translational levels in MMG-cultured lymphocytes compared with 1-g controls. Events upstream of PKC, such as phosphorylation of phospholipase Cgamma in MMG, revealed accumulation of inactive enzyme. Depressed calcium-independent PKC isoforms may be a consequence of an upstream lesion in the signal transduction pathway. The differential response among calcium-dependent and calcium-independent isoforms may actually result from MMG intrusion events earlier than PKC, but after ligand-receptor interaction.

  16. Identification of alternatively translated Tetherin isoforms with differing antiviral and signaling activities.

    Directory of Open Access Journals (Sweden)

    Luis J Cocka

    2012-09-01

    Full Text Available Tetherin (BST-2/CD317/HM1.24 is an IFN induced transmembrane protein that restricts release of a broad range of enveloped viruses. Important features required for Tetherin activity and regulation reside within the cytoplasmic domain. Here we demonstrate that two isoforms, derived by alternative translation initiation from highly conserved methionine residues in the cytoplasmic domain, are produced in both cultured human cell lines and primary cells. These two isoforms have distinct biological properties. The short isoform (s-Tetherin, which lacks 12 residues present in the long isoform (l-Tetherin, is significantly more resistant to HIV-1 Vpu-mediated downregulation and consequently more effectively restricts HIV-1 viral budding in the presence of Vpu. s-Tetherin Vpu resistance can be accounted for by the loss of serine-threonine and tyrosine motifs present in the long isoform. By contrast, the l-Tetherin isoform was found to be an activator of nuclear factor-kappa B (NF-κB signaling whereas s-Tetherin does not activate NF-κB. Activation of NF-κB requires a tyrosine-based motif found within the cytoplasmic tail of the longer species and may entail formation of l-Tetherin homodimers since co-expression of s-Tetherin impairs the ability of the longer isoform to activate NF-κB. These results demonstrate a novel mechanism for control of Tetherin antiviral and signaling function and provide insight into Tetherin function both in the presence and absence of infection.

  17. PI3K isoform-selective inhibitors: next-generation targeted cancer therapies.

    Science.gov (United States)

    Wang, Xiang; Ding, Jian; Meng, Ling-hua

    2015-10-01

    The pivotal roles of phosphatidylinositol 3-kinases (PI3Ks) in human cancers have inspired active development of small molecules to inhibit these lipid kinases. However, the first-generation pan-PI3K and dual-PI3K/mTOR inhibitors have encountered problems in clinical trials, with limited efficacies as a monotherapeutic agent as well as a relatively high rate of side effects. It is increasingly recognized that different PI3K isoforms play non-redundant roles in particular tumor types, which has prompted the development of isoform-selective inhibitors for pre-selected patients with the aim for improving efficacy while decreasing undesirable side effects. The success of PI3K isoform-selective inhibitors is represented by CAL101 (Idelalisib), a first-in-class PI3Kδ-selective small-molecule inhibitor that has been approved by the FDA for the treatment of chronic lymphocytic leukemia, indolent B-cell non-Hodgkin's lymphoma and relapsed small lymphocytic lymphoma. Inhibitors targeting other PI3K isoforms are also being extensively developed. This review focuses on the recent progress in development of PI3K isoform-selective inhibitors for cancer therapy. A deeper understanding of the action modes of novel PI3K isoform-selective inhibitors will provide valuable information to further validate the concept of targeting specific PI3K isoforms, while the identification of biomarkers to stratify patients who are likely to benefit from the therapy will be essential for the success of these agents. PMID:26364801

  18. Male-specific Fruitless isoforms have different regulatory roles conferred by distinct zinc finger DNA binding domains

    OpenAIRE

    Dalton, Justin E.; Fear, Justin M.; Knott, Simon; Baker, Bruce S.; McIntyre, Lauren M.; Arbeitman, Michelle N.

    2013-01-01

    Background Drosophila melanogaster adult males perform an elaborate courtship ritual to entice females to mate. fruitless (fru), a gene that is one of the key regulators of male courtship behavior, encodes multiple male-specific isoforms (FruM). These isoforms vary in their carboxy-terminal zinc finger domains, which are predicted to facilitate DNA binding. Results By over-expressing individual FruM isoforms in fru-expressing neurons in either males or females and assaying the global transcri...

  19. Functional Analysis of the Short Isoform of Orf Virus Protein OV20.0

    Science.gov (United States)

    Tseng, Yeu-Yang; Lin, Fong-Yuan; Cheng, Sun-Fang; Chulakasian, Songkhla; Chou, Chia-Chi; Liu, Ya-Fen; Chang, Wei-Shan; Wong, Min-Liang

    2015-01-01

    ABSTRACT Orf virus (ORFV) OV20.0L is an ortholog of vaccinia virus (VACV) gene E3L. The function of VACV E3 protein as a virulence factor is well studied, but OV20.0 has received less attention. Here we show that like VACV E3L, OV20.0L encodes two proteins, a full-length protein and a shorter form (sh20). The shorter sh20 is an N-terminally truncated OV20.0 isoform generated when a downstream AUG codon is used for initiating translation. These isoforms differed in cellular localization, with full-length OV20.0 and sh20 found throughout the cell and predominantly in the cytoplasm, respectively. Nonetheless, both OV20.0 isoforms were able to bind double-stranded RNA (dsRNA)-activated protein kinase (PKR) and dsRNA. Moreover, both isoforms strongly inhibited PKR activation as shown by decreased phosphorylation of the translation initiation factor eIF2α subunit and protection of Sindbis virus infection against the activity of interferon (IFN). In spite of this apparent conservation of function in vitro, a recombinant ORFV that was able to express only the sh20 isoform was attenuated in a mouse model. IMPORTANCE The OV20.0 protein of orf virus (ORFV) has two isoforms and contributes to virulence, but the roles of the two forms are not known. This study shows that the shorter isoform (sh20) arises due to use of a downstream initiation codon and is amino-terminally truncated. The sh20 form also differs in expression kinetics and cellular localization from full-length OV20.0. Similar to the full-length isoform, sh20 is able to bind dsRNA and PKR, inactivate PKR, and thus act as an antagonist of the interferon response in vitro. In vivo, however, wild-type OV20.0 could not be replaced with sh20 alone without a loss of virulence, suggesting that the functions of the isoforms are not simply redundant. PMID:25694596

  20. Regulation of three isoforms of SOD gene by environmental stresses in citrus red mite, Panonychus citri.

    Science.gov (United States)

    Feng, Ying-Cai; Liao, Chong-Yu; Xia, Wen-Kai; Jiang, Xuan-Zhao; Shang, Feng; Yuan, Guo-Rui; Wang, Jin-Jun

    2015-09-01

    Superoxide dismutase (SOD) is a family of enzymes with multiple isoforms that possess antioxidative abilities in response to environmental stresses. Panonychus citri is one of the most important pest mites and has a global distribution. In this study, three distinct isoforms of SOD were cloned from P. citri and identified as cytoplasmic Cu-ZnSOD (PcSOD1), extracellular Cu-ZnSOD (PcSOD2), and mitochondrial MnSOD (PcSOD3). mRNA expression level analysis showed that all three isoforms were up-regulated significantly after exposure to the acaricide abamectin and to UV-B ultraviolet irradiation. In particular, PcSOD3 was up-regulated under almost all environmental stresses tested. The fold change of PcSOD3 expression was significantly higher than those of the two Cu-ZnSOD isoforms. Taken together, the results indicate that abamectin and UV-B can induce transcripts of all three SOD isoforms in P. citri. Furthermore, PcSOD3 seems to play a more important role in P. citri tolerance to oxidative stress. PMID:26063404

  1. [Preparation and properties of isocitrate lyase isoforms from the cotyledons of Glycine max L].

    Science.gov (United States)

    Eprintsev, A T; Diachenko, E V; Lykova, T V; Kuen, C T H; Popov, V N

    2010-01-01

    A four-stage purification procedure including ammonium sulfate precipitation and ion exchange chromatography on DEAE cellulose has been elaborated for isolation of isocitrate lyase (EC 4.1.3.1) isoforms from the cotyledons of soybean Glycine max L. Electrophoretically homogeneous preparations of two forms of the enzyme with specific activity of 5.28 and 5.81 U/mg protein have been obtained. Comparison of physicochemical, kinetic, and regulation characteristics of the isoforms obtained revealed fundamental differences between them. Thus, the isoform that migrated quickly in PAAG had a much lower affinity to isocitrate (K(M) - 50 microM) than the slowly migrating form (K(M) - 16 microM). It has been shown that the conservation of activity of the isoforms obtained depends on the presence of divalent cations (Mn2+ and Mg2+) in the medium. It is suggested to use the isoforms of isocitrate lyase isolated from soybeans for the development of biosensors for biochemical and kinetic assays. PMID:20198926

  2. Insulin receptor isoforms: an integrated view focused on gestational diabetes mellitus.

    Science.gov (United States)

    Westermeier, F; Sáez, T; Arroyo, P; Toledo, F; Gutiérrez, J; Sanhueza, C; Pardo, F; Leiva, A; Sobrevia, L

    2016-05-01

    The human insulin receptor (IR) exists in two isoforms that differ by the absence (IR-A) or the presence (IR-B) of a 12-amino acid segment encoded by exon 11. Both isoforms are functionally distinct regarding their binding affinities and intracellular signalling. However, the underlying mechanisms related to their cellular functions in several tissues are only partially understood. In this review, we summarize the current knowledge in this field regarding the alternative splicing of IR isoform, tissue-specific distribution and signalling both in physiology and disease, with an emphasis on the human placenta in gestational diabetes mellitus (GDM). Furthermore, we discuss the clinical relevance of IR isoforms highlighted by findings that show altered insulin signalling due to differential IR-A and IR-B expression in human placental endothelium in GDM pregnancies. Future research and clinical studies focused on the role of IR isoform signalling might provide novel therapeutic targets for treating GDM to improve the adverse maternal and neonatal outcomes. Copyright © 2015 John Wiley & Sons, Ltd. PMID:26431063

  3. Nesprin-2 epsilon: A novel nesprin isoform expressed in human ovary and Ntera-2 cells

    Energy Technology Data Exchange (ETDEWEB)

    Lam, Le Thanh [Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry SY10 7AG (United Kingdom); Boehm, Sabrina V.; Roberts, Roland G. [Department of Medical and Molecular Genetics, King' s College London, London SE1 9RT (United Kingdom); Morris, Glenn E., E-mail: glennmanc@hotmail.com [Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry SY10 7AG (United Kingdom); Institute of Science and Technology in Medicine, Keele University, Keele ST5 5BG (United Kingdom)

    2011-08-26

    Highlights: {yields} A novel epsilon isoform of nesprin-2 has been discovered. {yields} This 120 kDa protein was predicted by bioinformatic analysis, but has not previously been observed. {yields} It is the main isoform expressed in a teratocarcinoma cell line and is also found in ovary. {yields} Like other nesprins, it is located at the nuclear envelope. {yields} We suggest it may have a role in very early development or in some ovary-specific function. -- Abstract: The nuclear envelope-associated cytoskeletal protein, nesprin-2, is encoded by a large gene containing several internal promoters that produce shorter isoforms. In a study of Ntera-2 teratocarcinoma cells, a novel isoform, nesprin-2-epsilon, was found to be the major mRNA and protein product of the nesprin-2 gene. Its existence was predicted by bioinformatic analysis, but this is the first direct demonstration of both the mRNA and the 120 kDa protein which is located at the nuclear envelope. In a panel of 21 adult and foetal human tissues, the nesprin-2-epsilon mRNA was strongly expressed in ovary but was a minor isoform elsewhere. The expression pattern suggests a possible link with very early development and a likely physiological role in ovary.

  4. Most highly expressed protein-coding genes have a single dominant isoform.

    Science.gov (United States)

    Ezkurdia, Iakes; Rodriguez, Jose Manuel; Carrillo-de Santa Pau, Enrique; Vázquez, Jesús; Valencia, Alfonso; Tress, Michael L

    2015-04-01

    Although eukaryotic cells express a wide range of alternatively spliced transcripts, it is not clear whether genes tend to express a range of transcripts simultaneously across cells, or produce dominant isoforms in a manner that is either tissue-specific or regardless of tissue. To date, large-scale investigations into the pattern of transcript expression across distinct tissues have produced contradictory results. Here, we attempt to determine whether genes express a dominant splice variant at the protein level. We interrogate peptides from eight large-scale human proteomics experiments and databases and find that there is a single dominant protein isoform, irrespective of tissue or cell type, for the vast majority of the protein-coding genes in these experiments, in partial agreement with the conclusions from the most recent large-scale RNAseq study. Remarkably, the dominant isoforms from the experimental proteomics analyses coincided overwhelmingly with the reference isoforms selected by two completely orthogonal sources, the consensus coding sequence variants, which are agreed upon by separate manual genome curation teams, and the principal isoforms from the APPRIS database, predicted automatically from the conservation of protein sequence, structure, and function. PMID:25732134

  5. Computational Estimates of Binding Affinities for Estrogen Receptor Isoforms in Rainbow Trout

    CERN Document Server

    Shyu, Conrad

    2009-01-01

    Molecular dynamics simulations are performed to determine the binding affinities between the hormone 17 beta-estradiol (E2) and different estrogen receptor (ER) isoforms in the rainbow trout (Oncorhynchus mykiss). Previous studies have demonstrated that a recent, unique gene duplication of the ER alpha subtype created two isoforms ER alpha 1 and ER alpha 2, and an early secondary split of ER beta produced two distinct isoforms of ER beta 1 and ER beta 2 based on the phylogenetic analysis. The objective of our computational studies is to provide insight into the underlying evolutionary selection pressure on the ER isoforms. Our results show that E2 binds preferentially to ER alpha 1. This finding corresponds to the experimental results as the ERs evolved from gene duplication events are frequently free from selective pressure and should exhibit no deleterious effects. The E2, however, only binds slightly better to ER beta 2. Both isoforms remain competitive. This finding reflects the fact that since ER beta 2 ...

  6. Electrophoretic Mobility of Cardiac Myosin Heavy Chain Isoforms Revisited: Application of MALDI TOF/TOF Analysis

    Directory of Open Access Journals (Sweden)

    Petra Arnostova

    2011-01-01

    Full Text Available The expression of two cardiac myosin heavy chain (MyHC isoforms in response to the thyroid status was studied in left ventricles (LVs of Lewis rats. Major MyHC isoform in euthyroid and hyperthyroid LVs had a higher mobility on SDS-PAGE, whereas hypothyroid LVs predominantly contained a MyHC isoform with a lower mobility corresponding to that of the control soleus muscle. By comparing the MyHC profiles obtained under altered thyroid states together with the control soleus, we concluded that MyHCα was represented by the lower band with higher mobility and MyHCβ by the upper band. The identity of these two bands in SDS-PAGE gels was confirmed by western blot and mass spectrometry. Thus, in contrast to the literature data, we found that the MyHCα possessed a higher mobility rate than the MyHCβ isoform. Our data highlighted the importance of the careful identification of the MyHCα and MyHCβ isoforms analyzed by the SDS-PAGE.

  7. Nesprin-2 epsilon: A novel nesprin isoform expressed in human ovary and Ntera-2 cells

    International Nuclear Information System (INIS)

    Highlights: → A novel epsilon isoform of nesprin-2 has been discovered. → This 120 kDa protein was predicted by bioinformatic analysis, but has not previously been observed. → It is the main isoform expressed in a teratocarcinoma cell line and is also found in ovary. → Like other nesprins, it is located at the nuclear envelope. → We suggest it may have a role in very early development or in some ovary-specific function. -- Abstract: The nuclear envelope-associated cytoskeletal protein, nesprin-2, is encoded by a large gene containing several internal promoters that produce shorter isoforms. In a study of Ntera-2 teratocarcinoma cells, a novel isoform, nesprin-2-epsilon, was found to be the major mRNA and protein product of the nesprin-2 gene. Its existence was predicted by bioinformatic analysis, but this is the first direct demonstration of both the mRNA and the 120 kDa protein which is located at the nuclear envelope. In a panel of 21 adult and foetal human tissues, the nesprin-2-epsilon mRNA was strongly expressed in ovary but was a minor isoform elsewhere. The expression pattern suggests a possible link with very early development and a likely physiological role in ovary.

  8. Quantitative profiling of Drosophila melanogaster Dscam1 isoforms reveals no changes in splicing after bacterial exposure.

    Directory of Open Access Journals (Sweden)

    Sophie A O Armitage

    Full Text Available The hypervariable Dscam1 (Down syndrome cell adhesion molecule 1 gene can produce thousands of different ectodomain isoforms via mutually exclusive alternative splicing. Dscam1 appears to be involved in the immune response of some insects and crustaceans. It has been proposed that the diverse isoforms may be involved in the recognition of, or the defence against, diverse parasite epitopes, although evidence to support this is sparse. A prediction that can be generated from this hypothesis is that the gene expression of specific exons and/or isoforms is influenced by exposure to an immune elicitor. To test this hypothesis, we for the first time, use a long read RNA sequencing method to directly investigate the Dscam1 splicing pattern after exposing adult Drosophila melanogaster and a S2 cell line to live Escherichia coli. After bacterial exposure both models showed increased expression of immune-related genes, indicating that the immune system had been activated. However there were no changes in total Dscam1 mRNA expression. RNA sequencing further showed that there were no significant changes in individual exon expression and no changes in isoform splicing patterns in response to bacterial exposure. Therefore our studies do not support a change of D. melanogaster Dscam1 isoform diversity in response to live E. coli. Nevertheless, in future this approach could be used to identify potentially immune-related Dscam1 splicing regulation in other host species or in response to other pathogens.

  9. Two isoforms of aquaporin 2 responsive to hypertonic stress in the bottlenose dolphin.

    Science.gov (United States)

    Suzuki, Miwa; Wakui, Hitomi; Itou, Takuya; Segawa, Takao; Inoshima, Yasuo; Maeda, Ken; Kikuchi, Kiyoshi

    2016-04-15

    This study investigated the expression of aquaporin 2 (AQP2) and its newly found alternatively spliced isoform (alternative AQP2) and the functions of these AQP2 isoforms in the cellular hyperosmotic tolerance in the bottlenose dolphin, ITALIC! Tursiops truncatus mRNA sequencing revealed that alternative AQP2 lacks the fourth exon and instead has a longer third exon that includes a part of the original third intron. The portion of the third intron, now part of the coding region of alternative AQP2, is highly conserved among many species of the order Cetacea but not among terrestrial mammals. Semi-quantitative PCR revealed that AQP2 was expressed only in the kidney, similar to terrestrial mammals. In contrast, alternative AQP2 was expressed in all organs examined, with strong expression in the kidney. In cultured renal cells, expression of both AQP2 isoforms was upregulated by the addition to the medium of NaCl but not by the addition of mannitol, indicating that the expression of both isoforms is induced by hypersalinity. Treatment with small interfering RNA for both isoforms resulted in a decrease in cell viability in hypertonic medium (500 mOsm kg(-1)) when compared with controls. These findings indicate that the expression of alternatively spliced AQP2 is ubiquitous in cetacean species, and it may be one of the molecules important for cellular osmotic tolerance throughout the body. PMID:26944501

  10. The relationship between gene isoform multiplicity, number of exons and protein divergence.

    Directory of Open Access Journals (Sweden)

    Jordi Morata

    Full Text Available At present we know that phenotypic differences between organisms arise from a variety of sources, like protein sequence divergence, regulatory sequence divergence, alternative splicing, etc. However, we do not have yet a complete view of how these sources are related. Here we address this problem, studying the relationship between protein divergence and the ability of genes to express multiple isoforms. We used three genome-wide datasets of human-mouse orthologs to study the relationship between isoform multiplicity co-occurrence between orthologs (the fact that two orthologs have more than one isoform and protein divergence. In all cases our results showed that there was a monotonic dependence between these two properties. We could explain this relationship in terms of a more fundamental one, between exon number of the largest isoform and protein divergence. We found that this last relationship was present, although with variations, in other species (chimpanzee, cow, rat, chicken, zebrafish and fruit fly. In summary, we have identified a relationship between protein divergence and isoform multiplicity co-occurrence and explained its origin in terms of a simple gene-level property. Finally, we discuss the biological implications of these findings for our understanding of inter-species phenotypic differences.

  11. iReckon: simultaneous isoform discovery and abundance estimation from RNA-seq data.

    Science.gov (United States)

    Mezlini, Aziz M; Smith, Eric J M; Fiume, Marc; Buske, Orion; Savich, Gleb L; Shah, Sohrab; Aparicio, Sam; Chiang, Derek Y; Goldenberg, Anna; Brudno, Michael

    2013-03-01

    High-throughput RNA sequencing (RNA-seq) promises to revolutionize our understanding of genes and their role in human disease by characterizing the RNA content of tissues and cells. The realization of this promise, however, is conditional on the development of effective computational methods for the identification and quantification of transcripts from incomplete and noisy data. In this article, we introduce iReckon, a method for simultaneous determination of the isoforms and estimation of their abundances. Our probabilistic approach incorporates multiple biological and technical phenomena, including novel isoforms, intron retention, unspliced pre-mRNA, PCR amplification biases, and multimapped reads. iReckon utilizes regularized expectation-maximization to accurately estimate the abundances of known and novel isoforms. Our results on simulated and real data demonstrate a superior ability to discover novel isoforms with a significantly reduced number of false-positive predictions, and our abundance accuracy prediction outmatches that of other state-of-the-art tools. Furthermore, we have applied iReckon to two cancer transcriptome data sets, a triple-negative breast cancer patient sample and the MCF7 breast cancer cell line, and show that iReckon is able to reconstruct the complex splicing changes that were not previously identified. QT-PCR validations of the isoforms detected in the MCF7 cell line confirmed all of iReckon's predictions and also showed strong agreement (r(2) = 0.94) with the predicted abundances. PMID:23204306

  12. Secretion of PDGF isoforms during osteoclastogenesis and its modulation by anti-osteoclast drugs.

    Science.gov (United States)

    Rahman, M Motiur; Matsuoka, Kazuhiko; Takeshita, Sunao; Ikeda, Kyoji

    2015-06-26

    In an attempt to identify secretory products of osteoclasts that mediate the coupling of bone formation to resorption, we found that along with osteoclast differentiation, PDGF-A gene expression increase occurred first, by 12 h after stimulation of bone marrow macrophages with M-CSF and RANKL, and peaked at 36 h. This was next followed by a progressive increase in PDGF-B gene expression until a peak at 60 h, when mature osteoclasts formed. Isoform-specific ELISA of the conditioned medium collected every 24 h revealed that all three of the isoforms of PDGF-AA, AB and BB were secreted, in this temporal order as differentiation proceeded. Their secretion was enhanced when osteoclasts were activated by placing them on dentin slices. The secretion of all three isoforms was decreased in cathepsin K-deficient osteoclasts compared with wild-type osteoclasts. Pharmacological inhibition of cathepsin K with odanacatib also inhibited the secretion of all three isoforms, as was also the case with alendronate treatment. The secretion of sphingosine-1-phosphate, which increased during osteoclastogenesis, was reduced from cathepsin K-deficient osteoclasts, and was inhibited by treatment with odanacatib more profoundly than with alendronate. Thus, all three isoforms of PDGF, which are secreted at distinct differentiation stages of osteoclasts, appear to have distinct roles in the cell-cell communication that takes place in the microenvironment of bone remodeling, especially from the osteoclast lineage to mesenchymal cells and vascular cells, thereby stimulating osteogenesis and angiogenesis. PMID:25951977

  13. Thermal Denaturation and Aggregation of Myosin Subfragment 1 Isoforms with Different Essential Light Chains

    Directory of Open Access Journals (Sweden)

    Eugene O. Zubov

    2010-10-01

    Full Text Available We compared thermally induced denaturation and aggregation of two isoforms of the isolated myosin head (myosin subfragment 1, S1 containing different “essential” (or “alkali” light chains, A1 or A2. We applied differential scanning calorimetry (DSC to investigate the domain structure of these two S1 isoforms. For this purpose, a special calorimetric approach was developed to analyze the DSC profiles of irreversibly denaturing multidomain proteins. Using this approach, we revealed two calorimetric domains in  the S1 molecule, the more thermostable domain denaturing in two steps. Comparing the DSC data with temperature dependences of intrinsic fluorescence parameters and S1 ATPase inactivation, we have identified these two calorimetric domains as motor domain and regulatory domain of the myosin head, the motor domain being more thermostable. Some difference between the two S1 isoforms was only revealed by DSC in thermal denaturation of the regulatory domain. We also applied dynamic light scattering (DLS to analyze the aggregation of S1 isoforms induced by their thermal denaturation. We have found no appreciable difference between these S1 isoforms in their aggregation properties under ionic strength conditions close to those in the muscle fiber (in the presence of 100 mM KCl. Under these conditions kinetics of this process was independent of protein concentration, and the aggregation rate was limited by irreversible denaturation of the S1 motor domain.

  14. Alterations of Lymphoid Enhancer Factor-1 Isoform Expression in Solid Tumors and Acute Leukemias

    Institute of Scientific and Technical Information of China (English)

    Wenbing WANG; Carsten M(U)LLER-TIDOW; Ping JI; Bj(o)rn STEFFEN; Ralf METZGER; Paul M. SCHNEIDER; Hartmut HALFTER; Mark SCHRADER; Wolfgang E. BERDEL; Hubert SERVE

    2005-01-01

    Two major transcripts of lymphoid enhancer factor-1 (LEF-1) have been described. The long isoform with β-catenin binding domain functions as a transcriptional enhancer factor. The short isoform derives from an intronic promoter and exhibits dominant negative activity. Recently, alterations of LEF- 1isoforms distribution have been described in colon cancer. In the current study we employed a quantitative real-time reverse transcription PCR method (TaqMan) to analyze expression of LEF-1 isoforms in a large cohort of human tumor (n=304) and tumor-free control samples (n=56). The highest expression level of LEF-1 was found in carcinoma samples whereas brain cancer samples expressed little. Expression of LEF1 was different in distinct cancer types. For example, the mRNA level of LEF-1 was lower in testicular tumor samples compared with tumor-free control samples. Besides epithelial cancers, significant LEF-1expression was also found in hematopoietic cells. In hematological malignancies, overall LEF-1 level was higher in lymphocytic leukemias compared with myeloid leukemias and normal hematopoiesis. However,acute myeloid leukemia and acute lymphocytic leukemia showed a significantly increased fraction of the oncogenic LEF-1 compared with chronic lymphocytic leukemia and chronic myeloid leukemia. Taken together,these data suggest that LEF-1 is abundantly expressed in human tumors and the ratio of the oncogenic and the dominant negative short isoform altered not only in carcinomas but also in leukemia.

  15. Serum amyloid A isoforms in serum and synovial fluid from spontaneously diseased dogs with joint diseases or other conditions

    DEFF Research Database (Denmark)

    Kjelgaard-Hansen, Mads Jens; Christensen, Michelle B.; Lee, Marcel Huisung;

    2007-01-01

    in samples obtained from dogs (n = 16) suffering from different inflammatory or non-inflammatory conditions, which were either related or unrelated to joints. Expression of SAA isoforms was visualized by denaturing isoelectric focusing and Western blotting. Serum amyloid A was present in serum from all dogs...... with systemic inflammatory activity, and up to four major isoforms with apparent isoelectric points between 6.1 and 7.9 were identified. In synovial fluid from inflamed joints one or more highly alkaline SAA isoforms (with apparent isoelectric points above 9.3) were identified, with data suggesting local...... production of these isoforms in the canine inflamed joint....

  16. Glucocorticoid receptor translational isoforms underlie maturational stage-specific glucocorticoid sensitivities of dendritic cells in mice and humans

    OpenAIRE

    Cao, Yun; Bender, Ingrid K.; Konstantinidis, Athanasios K.; Shin, Soon Cheon; Jewell, Christine M.; Cidlowski, John A; Schleimer, Robert P.; Lu, Nick Z.

    2013-01-01

    Mature, but not immature, dendritic cells are sensitive to glucocorticoid-induced apoptosis.Mature, but not immature, dendritic cells express proapoptotic glucocorticoid receptor translational isoforms.

  17. Altered CD45 isoform expression affects lymphocyte function in CD45 Tg mice.

    Science.gov (United States)

    Tchilian, Elma Z; Dawes, Ritu; Hyland, Lisa; Montoya, Maria; Le Bon, Agnes; Borrow, Persephone; Hou, Sam; Tough, David; Beverley, Peter C L

    2004-09-01

    Transgenic mice have been constructed expressing high (CD45RABC) and low (CD45R0) molecular weight CD45 isoforms on a CD45-/- background. Phenotypic analysis and in vivo challenge of these mice with influenza and lymphocytic choriomeningitis viruses shows that T cell differentiation and peripheral T cell function are related to the level of CD45 expression but not to which CD45 isoform is expressed. In contrast, B cell differentiation is not restored, irrespective of the level of expression of a single isoform. All CD45 trangenic mice have T cells with an activated phenotype and increased T cell turnover. These effects are more prominent in CD8 than CD4 cells. The transgenic mice share several properties with humans expressing variant CD45 alleles and provide a model to understand immune function in variant individuals. PMID:15302847

  18. Structural and Functional Characterization of Recombinant Isoforms of the Lentil Lipid Transfer Protein.

    Science.gov (United States)

    Bogdanov, I V; Finkina, E I; Balandin, S V; Melnikova, D N; Stukacheva, E A; Ovchinnikova, T V

    2015-01-01

    The recombinant isoforms Lc-LTP1 and Lc-LTP3 of the lentil lipid transfer protein were overexpressed in E. coli cells. It was confirmed that both proteins are stabilized by four disulfide bonds and characterized by a high proportion of the α-helical structure. It was found that Lc-LTP1 and Lc-LTP3 possess antimicrobial activity and can bind fatty acids. Both isoforms have the ability to bind specific IgE from sera of patients with food allergies, which recognize similar epitopes of the major peach allergen Pru p 3. Both isoforms were shown to have immunological properties similar to those of other plant allergenic LTPs, but Lc-LTP3 displayed a less pronounced immunoreactivity. PMID:26483961

  19. Exposing the specific roles of the invariant chain isoforms in shaping the MHC class II peptidome

    Directory of Open Access Journals (Sweden)

    Jean-Simon eFortin

    2013-12-01

    Full Text Available The peptide repertoire (peptidome associated with MHC class II molecules (MHCIIs is influenced by the polymorphic nature of the peptide binding groove but also by cell-intrinsic factors. The invariant chain (Ii chaperones MHCIIs, affecting their folding and trafficking. Recent discoveries relating to Ii functions have provided insights as to how it edits the MHCII peptidome. In humans, the Ii gene encodes four different isoforms for which structure-function analyses have highlighted common properties but also some non-redundant roles. Another layer of complexity arises from the fact that Ii heterotrimerizes, a characteristic that has the potential to affect the maturation of associated MHCIIs in many different ways, depending on the isoform combinations. Here, we emphasize the peptide editing properties of Ii and discuss the impact of the various isoforms on the MHCII peptidome.

  20. Unraveling complex interplay between heat shock factor 1 and 2 splicing isoforms.

    Directory of Open Access Journals (Sweden)

    Sylvain Lecomte

    Full Text Available Chaperone synthesis in response to proteotoxic stress is dependent on a family of transcription factors named heat shock factors (HSFs. The two main factors in this family, HSF1 and HSF2, are co-expressed in numerous tissues where they can interact and form heterotrimers in response to proteasome inhibition. HSF1 and HSF2 exhibit two alternative splicing isoforms, called α and β, which contribute to additional complexity in HSF transcriptional regulation, but remain poorly examined in the literature. In this work, we studied the transcriptional activity of HSF1 and HSF2 splicing isoforms transfected into immortalized Mouse Embryonic Fibroblasts (iMEFs deleted for both Hsf1 and Hsf2, under normal conditions and after proteasome inhibition. We found that HSF1α is significantly more active than the β isoform after exposure to the proteasome inhibitor MG132. Furthermore, we clearly established that, while HSF2 had no transcriptional activity by itself, short β isoform of HSF2 exerts a negative role on HSF1β-dependent transactivation. To further assess the impact of HSF2β inhibition on HSF1 activity, we developed a mathematical modelling approach which revealed that the balance between each HSF isoform in the cell regulated the strength of the transcriptional response. Moreover, we found that cellular stress such as proteasome inhibition could regulate the splicing of Hsf2 mRNA. All together, our results suggest that relative amounts of each HSF1 and HSF2 isoforms quantitatively determine the cellular level of the proteotoxic stress response.

  1. The α and Δ isoforms of CREB1 are required to maintain normal pulmonary vascular resistance.

    Directory of Open Access Journals (Sweden)

    Lili Li

    Full Text Available Chronic hypoxia causes pulmonary hypertension associated with structural alterations in pulmonary vessels and sustained vasoconstriction. The transcriptional mechanisms responsible for these distinctive changes are unclear. We have previously reported that CREB1 is activated in the lung in response to alveolar hypoxia but not in other organs. To directly investigate the role of α and Δ isoforms of CREB1 in the regulation of pulmonary vascular resistance we examined the responses of mice in which these isoforms of CREB1 had been inactivated by gene mutation, leaving only the β isoform intact (CREB(αΔ mice. Here we report that expression of CREB regulated genes was altered in the lungs of CREB(αΔ mice. CREB(αΔ mice had greater pulmonary vascular resistance than wild types, both basally in normoxia and following exposure to hypoxic conditions for three weeks. There was no difference in rho kinase mediated vasoconstriction between CREB(αΔ and wild type mice. Stereological analysis of pulmonary vascular structure showed characteristic wall thickening and lumen reduction in hypoxic wild-type mice, with similar changes observed in CREB(αΔ. CREB(αΔ mice had larger lungs with reduced epithelial surface density suggesting increased pulmonary compliance. These findings show that α and Δ isoforms of CREB1 regulate homeostatic gene expression in the lung and that normal activity of these isoforms is essential to maintain low pulmonary vascular resistance in both normoxic and hypoxic conditions and to maintain the normal alveolar structure. Interventions that enhance the actions of α and Δ isoforms of CREB1 warrant further investigation in hypoxic lung diseases.

  2. Comparative proteomics reveals a significant bias toward alternative protein isoforms with conserved structure and function.

    Science.gov (United States)

    Ezkurdia, Iakes; del Pozo, Angela; Frankish, Adam; Rodriguez, Jose Manuel; Harrow, Jennifer; Ashman, Keith; Valencia, Alfonso; Tress, Michael L

    2012-09-01

    Advances in high-throughput mass spectrometry are making proteomics an increasingly important tool in genome annotation projects. Peptides detected in mass spectrometry experiments can be used to validate gene models and verify the translation of putative coding sequences (CDSs). Here, we have identified peptides that cover 35% of the genes annotated by the GENCODE consortium for the human genome as part of a comprehensive analysis of experimental spectra from two large publicly available mass spectrometry databases. We detected the translation to protein of "novel" and "putative" protein-coding transcripts as well as transcripts annotated as pseudogenes and nonsense-mediated decay targets. We provide a detailed overview of the population of alternatively spliced protein isoforms that are detectable by peptide identification methods. We found that 150 genes expressed multiple alternative protein isoforms. This constitutes the largest set of reliably confirmed alternatively spliced proteins yet discovered. Three groups of genes were highly overrepresented. We detected alternative isoforms for 10 of the 25 possible heterogeneous nuclear ribonucleoproteins, proteins with a key role in the splicing process. Alternative isoforms generated from interchangeable homologous exons and from short indels were also significantly enriched, both in human experiments and in parallel analyses of mouse and Drosophila proteomics experiments. Our results show that a surprisingly high proportion (almost 25%) of the detected alternative isoforms are only subtly different from their constitutive counterparts. Many of the alternative splicing events that give rise to these alternative isoforms are conserved in mouse. It was striking that very few of these conserved splicing events broke Pfam functional domains or would damage globular protein structures. This evidence of a strong bias toward subtle differences in CDS and likely conserved cellular function and structure is remarkable and

  3. Different characteristics and nucleotide binding properties of inosine monophosphate dehydrogenase (IMPDH isoforms.

    Directory of Open Access Journals (Sweden)

    Elaine C Thomas

    Full Text Available We recently reported that Inosine Monophosphate Dehydrogenase (IMPDH, a rate-limiting enzyme in de novo guanine nucleotide biosynthesis, clustered into macrostructures in response to decreased nucleotide levels and that there were differences between the IMPDH isoforms, IMPDH1 and IMPDH2. We hypothesised that the Bateman domains, which are present in both isoforms and serve as energy-sensing/allosteric modules in unrelated proteins, would contribute to isoform-specific differences and that mutations situated in and around this domain in IMPDH1 which give rise to retinitis pigmentosa (RP would compromise regulation. We employed immuno-electron microscopy to investigate the ultrastructure of IMPDH macrostructures and live-cell imaging to follow clustering of an IMPDH2-GFP chimera in real-time. Using a series of IMPDH1/IMPDH2 chimera we demonstrated that the propensity to cluster was conferred by the N-terminal 244 amino acids, which includes the Bateman domain. A protease protection assay suggested isoform-specific purine nucleotide binding characteristics, with ATP protecting IMPDH1 and AMP protecting IMPDH2, via a mechanism involving conformational changes upon nucleotide binding to the Bateman domain without affecting IMPDH catalytic activity. ATP binding to IMPDH1 was confirmed in a nucleotide binding assay. The RP-causing mutation, R224P, abolished ATP binding and nucleotide protection and this correlated with an altered propensity to cluster. Collectively these data demonstrate that (i the isoforms are differentially regulated by AMP and ATP by a mechanism involving the Bateman domain, (ii communication occurs between the Bateman and catalytic domains and (iii the RP-causing mutations compromise such regulation. These findings support the idea that the IMPDH isoforms are subject to distinct regulation and that regulatory defects contribute to human disease.

  4. Glutamic acid decarboxylase isoform distribution in transgenic mouse septum: an anti-GFP immunofluorescence study.

    Science.gov (United States)

    Verimli, Ural; Sehirli, Umit S

    2016-09-01

    The septum is a basal forebrain region located between the lateral ventricles in rodents. It consists of lateral and medial divisions. Medial septal projections regulate hippocampal theta rhythm whereas lateral septal projections are involved in processes such as affective functions, memory formation, and behavioral responses. Gamma-aminobutyric acidergic neurons of the septal region possess the 65 and 67 isoforms of the enzyme glutamic acid decarboxylase. Although data on the glutamic acid decarboxylase isoform distribution in the septal region generally appears to indicate glutamic acid decarboxylase 67 dominance, different studies have given inconsistent results in this regard. The aim of this study was therefore to obtain information on the distributions of both of these glutamic acid decarboxylase isoforms in the septal region in transgenic mice. Two animal groups of glutamic acid decarboxylase-green fluorescent protein knock-in transgenic mice were utilized in the experiment. Brain sections from the region were taken for anti-green fluorescent protein immunohistochemistry in order to obtain estimated quantitative data on the number of gamma-aminobutyric acidergic neurons. Following the immunohistochemical procedures, the mean numbers of labeled cells in the lateral and medial septal nuclei were obtained for the two isoform groups. Statistical analysis yielded significant results which indicated that the 65 isoform of glutamic acid decarboxylase predominates in both lateral and medial septal nuclei (unpaired two-tailed t-test p first to reveal the dominance of glutamic acid decarboxylase isoform 65 in the septal region in glutamic acid decarboxylase-green fluorescent protein transgenic mice. PMID:26643381

  5. Crystal structures of a halophilic archaeal malate synthase from Haloferax volcanii and comparisons with isoforms A and G

    Directory of Open Access Journals (Sweden)

    Thomas Geoffrey C

    2011-05-01

    Full Text Available Abstract Background Malate synthase, one of the two enzymes unique to the glyoxylate cycle, is found in all three domains of life, and is crucial to the utilization of two-carbon compounds for net biosynthetic pathways such as gluconeogenesis. In addition to the main isoforms A and G, so named because of their differential expression in E. coli grown on either acetate or glycolate respectively, a third distinct isoform has been identified. These three isoforms differ considerably in size and sequence conservation. The A isoform (MSA comprises ~530 residues, the G isoform (MSG is ~730 residues, and this third isoform (MSH-halophilic is ~430 residues in length. Both isoforms A and G have been structurally characterized in detail, but no structures have been reported for the H isoform which has been found thus far only in members of the halophilic Archaea. Results We have solved the structure of a malate synthase H (MSH isoform member from Haloferax volcanii in complex with glyoxylate at 2.51 Å resolution, and also as a ternary complex with acetyl-coenzyme A and pyruvate at 1.95 Å. Like the A and G isoforms, MSH is based on a β8/α8 (TIM barrel. Unlike previously solved malate synthase structures which are all monomeric, this enzyme is found in the native state as a trimer/hexamer equilibrium. Compared to isoforms A and G, MSH displays deletion of an N-terminal domain and a smaller deletion at the C-terminus. The MSH active site is closely superimposable with those of MSA and MSG, with the ternary complex indicating a nucleophilic attack on pyruvate by the enolate intermediate of acetyl-coenzyme A. Conclusions The reported structures of MSH from Haloferax volcanii allow a detailed analysis and comparison with previously solved structures of isoforms A and G. These structural comparisons provide insight into evolutionary relationships among these isoforms, and also indicate that despite the size and sequence variation, and the truncated C

  6. Investigating the role of the physiological isoform switch of cytochrome c oxidase subunits in reversible mitochondrial disease.

    Science.gov (United States)

    Boczonadi, Veronika; Giunta, Michele; Lane, Maria; Tulinius, Mar; Schara, Ulrike; Horvath, Rita

    2015-06-01

    Reversible infantile respiratory chain deficiency is characterised by spontaneous recovery of mitochondrial myopathy in infants. We studied whether a physiological isoform switch of nuclear cytochrome c oxidase subunits contributes to the age-dependent manifestation and spontaneous recovery in reversible mitochondrial disease. Some nuclear-encoded subunits of cytochrome c oxidase are present as tissue-specific isoforms. Isoforms of subunits COX6A and COX7A expressed in heart and skeletal muscle are different from isoforms expressed in the liver, kidney and brain. Furthermore, in skeletal muscle both the heart and liver isoforms of subunit COX7A have been demonstrated with variable levels, indicating that the tissue-specific expression of nuclear-encoded subunits could provide a basis for the fine-tuning of cytochrome c oxidase activity to the specific metabolic needs of the different tissues. We demonstrate a developmental isoform switch of COX6A and COX7A subunits in human and mouse skeletal muscle. While the liver type isoforms are more present soon after birth, the heart/muscle isoforms gradually increase around 3 months of age in infants, 4 weeks of age in mice, and these isoforms persist in muscle throughout life. Our data in follow-up biopsies of patients with reversible infantile respiratory chain deficiency indicate that the physiological isoform switch does not contribute to the clinical manifestation and to the spontaneous recovery of this disease. However, understanding developmental changes of the different cytochrome c oxidase isoforms may have implications for other mitochondrial diseases. This article is part of a Directed Issue entitled: Energy Metabolism Disorders and Therapies. PMID:25666558

  7. Characterization of PR-10 genes from eight Betula species and detection of Bet v 1 isoforms in birch pollen

    Directory of Open Access Journals (Sweden)

    van't Westende Wendy PC

    2009-03-01

    Full Text Available Abstract Background Bet v 1 is an important cause of hay fever in northern Europe. Bet v 1 isoforms from the European white birch (Betula pendula have been investigated extensively, but the allergenic potency of other birch species is unknown. The presence of Bet v 1 and closely related PR-10 genes in the genome was established by amplification and sequencing of alleles from eight birch species that represent the four subgenera within the genus Betula. Q-TOF LC-MSE was applied to identify which PR-10/Bet v 1 genes are actually expressed in pollen and to determine the relative abundances of individual isoforms in the pollen proteome. Results All examined birch species contained several PR-10 genes. In total, 134 unique sequences were recovered. Sequences were attributed to different genes or pseudogenes that were, in turn, ordered into seven subfamilies. Five subfamilies were common to all birch species. Genes of two subfamilies were expressed in pollen, while each birch species expressed a mixture of isoforms with at least four different isoforms. Isoforms that were similar to isoforms with a high IgE-reactivity (Bet v 1a = PR-10.01A01 were abundant in all species except B. lenta, while the hypoallergenic isoform Bet v 1d (= PR-10.01B01 was only found in B. pendula and its closest relatives. Conclusion Q-TOF LC-MSE allows efficient screening of Bet v 1 isoforms by determining the presence and relative abundance of these isoforms in pollen. B. pendula contains a Bet v 1-mixture in which isoforms with a high and low IgE-reactivity are both abundant. With the possible exception of B. lenta, isoforms identical or very similar to those with a high IgE-reactivity were found in the pollen proteome of all examined birch species. Consequently, these species are also predicted to be allergenic with regard to Bet v 1 related allergies.

  8. Involvement of specific calmodulin isoforms in salicylic acid-independent activation of plant disease resistance responses

    OpenAIRE

    Heo, Won Do; Lee, Sang Hyoung; Kim, Min Chul; Kim, Jong Cheol; Chung, Woo Sik; Chun, Hyun Jin; Lee, Kyoung Joo; Park, Chan Young; Park, Hyeong Cheol; Choi, Ji Young; Cho, Moo Je

    1999-01-01

    The Ca2+ signal is essential for the activation of plant defense responses, but downstream components of the signaling pathway are still poorly defined. Here we demonstrate that specific calmodulin (CaM) isoforms are activated by infection or pathogen-derived elicitors and participate in Ca2+-mediated induction of plant disease resistance responses. Soybean CaM (SCaM)-4 and SCaM-5 genes, which encode for divergent CaM isoforms, were induced within 30 min by a fungal elicitor or pathogen, wher...

  9. Changes in claudin isoform expression in the gill during salinity shifts and smoltification of Atlantic salmon

    DEFF Research Database (Denmark)

    Madsen, Steffen; Tipsmark, Christian Kølbæk

    2008-01-01

    expression was confirmed by RT-QPCR. We examined the expression profile during the parr-smolt transformation (PST) in freshwater and during acclimation to sea water (SW). During PST, claudin 10e expression peaked in May, coinciding with optimal SW tolerance. The other claudin isoforms were not influenced...... during PST. SW-transfer induced a 5-fold increase in expression of claudin 10e, reduced the expression of 27a and 30a and had no overall effect on 28a and 28b isoforms. The study demonstrates for the first time that SW acclimation involves differential regulation of claudin gene expression in the salmon...

  10. Expression of Tropomyosin 1 Gene Isoforms in Human Breast Cancer Cell Lines

    OpenAIRE

    Syamalima Dube; Santhi Yalamanchili; Joseph Lachant; Lynn Abbott; Patricia Benz; Charles Mitschow; Dube, Dipak K; Poiesz, Bernard J.

    2015-01-01

    Nine malignant breast epithelial cell lines and 3 normal breast cell lines were examined for stress fiber formation and expression of TPM1 isoform-specific RNAs and proteins. Stress fiber formation was strong (++++) in the normal cell lines and varied among the malignant cell lines (negative to +++). Although TPM1γ and TPM1δ were the dominant transcripts of TPM1, there was no clear evidence for TPM1δ protein expression. Four novel human TPM1 gene RNA isoforms were discovered (λ, μ, ν, and ξ),...

  11. Properties of SEPT9 isoforms and the requirement for GTP binding.

    Science.gov (United States)

    Robertson, Claire; Church, Stewart W; Nagar, Hans A; Price, John; Hall, Peter A; Russell, S E Hilary

    2004-05-01

    Members of the evolutionarily conserved septin family of genes are emerging as key components of several cellular processes including membrane trafficking, cytokinesis, and cell-cycle control events. SEPT9 has been shown to have a complex genomic architecture, such that up to 15 different isoforms are possible by the shuffling of five alternate amino termini and three alternate carboxy termini. Genomic and transcriptional alterations of SEPT9 have been associated with neoplasia. The present study has used a Sept9-specific antibody to determine the pattern of isoform expression in a range of tumour cell lines. Western blot analysis indicated considerable variation in the relative amounts and isoform content of Sept9. Immunofluorescence studies showed a range of patterns of cytoplasmic localization ranging from mainly particulate to mainly filamentous. Expression constructs were also generated for each amino terminal isoform to investigate the patterns of localization of individual isoforms and the effects on cells of ectopic expression. The present study shows that the epsilon isoform appears filamentous in this overexpression system while the remaining isoforms are particulate and cytoplasmic. Transient transfection of individual constructs into tumour cell lines results in cell-cycle perturbation with a G2/M arrest and dramatic growth suppression, which was greatest in cell lines with the lowest amounts of endogenous Sept9. Similar phenotypic observations were made with GTP-binding mutants of all five N-terminal variants of Sept9. However, dramatic differences were observed in the kinetics of accumulation of wild-type versus mutant septin protein in transfected cells. In conclusion, the present study shows that the expression patterns of Sept9 protein are very varied in a panel of tumour cell lines and the functional studies are consistent with a model of septin function as a component of a molecular scaffold that contributes to diverse cellular functions

  12. Two farnesoid X receptor alpha isoforms in Japanese medaka (Oryzias latipes) are differentially activated in vitro

    OpenAIRE

    Howarth, Deanna L.; Hagey, Lee R.; Law, Sheran H.W.; Ai, Ni; Krasowski, Matthew D.; Ekins, Sean; Moore, John T.; Erin M Kollitz; Hinton, David E.; Kullman, Seth W.

    2010-01-01

    The nuclear receptor farnesoid X receptor alpha (FXRα, NR1H4) is activated by bile acids in multiple species including mouse, rat, and human and in this study we have identified two isoforms of Fxrα in Japanese medaka (Oryzias latipes), a small freshwater teleost. Both isoforms share a high amino acid sequence identity to mammalian FXRα (~70% in the ligand-binding domain). Fxrα1 and Fxrα2 differ within the AF1 domain due to alternative splicing at the fourth intron-exon boundary. This process...

  13. Specific isoforms of translation initiation factor 4GI show differences in translational activity

    OpenAIRE

    Coldwell, M. J.; Morley, S J

    2006-01-01

    The eukaryotic initiation factor (eIF) 4GI gene locus (eIF4GI) contains three identified promoters, generating alternately spliced mRNAs, yielding a total of five eIF4GI protein isoforms. Although eIF4GI plays a critical role in mRNA recruitment to the ribosomes, little is known about the functions of the different isoforms, their partner binding capacities, or the role of the homolog, eIF4GII, in translation initiation. To directly address this, we have used short interfering RNAs (siRNAs) e...

  14. Alternative Splicing Regulates the Subcellular Localization of Divalent Metal Transporter 1 Isoforms

    OpenAIRE

    Tabuchi, Mitsuaki; Tanaka, Naotaka; Nishida-Kitayama, Junko; Ohno, Hiroshi; Kishi, Fumio

    2002-01-01

    Divalent metal transporter 1 (DMT1) is responsible for dietary-iron absorption from apical plasma membrane in the duodenum and iron acquisition from the transferrin cycle endosomes in peripheral tissues. Two isoforms of the DMT1 transcript generated by alternative splicing of the 3′ exons have been identified in mouse, rat, and human. These isoforms can be distinguished by the different C-terminal amino acid sequences and by the presence (DMT1A) or absence (DMT1B) of an iron response element ...

  15. Distribution of protein kinase Mzeta and the complete protein kinase C isoform family in rat brain

    DEFF Research Database (Denmark)

    Naik, M U; Benedikz, Eirikur; Hernandez, I;

    2000-01-01

    Protein kinase C (PKC) is a multigene family of at least ten isoforms, nine of which are expressed in brain (alpha, betaI, betaII, gamma, delta, straightepsilon, eta, zeta, iota/lambda). Our previous studies have shown that many of these PKCs participate in synaptic plasticity in the CA1 region of......, protein kinase Mzeta (PKMzeta). In this study, we used immunoblot and immunocytochemical techniques with isoform-specific antisera to examine the distribution of the complete family of PKC isozymes and PKMzeta in rat brain. Each form of PKC showed a widespread distribution in the brain with a distinct...

  16. Myosin Isoforms and Contractile Properties of Single Fibers of Human Latissimus Dorsi Muscle

    OpenAIRE

    Antonio Paoli; Pacelli, Quirico F.; Pasqua Cancellara; Luana Toniolo; Tatiana Moro; Marta Canato; Danilo Miotti; Carlo Reggiani

    2013-01-01

    The aim of our study was to investigate fiber type distribution and contractile characteristics of Latissimus Dorsi muscle (LDM). Samples were collected from 18 young healthy subjects (9 males and 9 females) through percutaneous fine needle muscle biopsy. The results showed a predominance of fast myosin heavy chain isoforms (MyHC) with 42% of MyHC 2A and 25% of MyHC 2X, while MyHC 1 represented only 33%. The unbalance toward fast isoforms was even greater in males (71%) than in females (64%...

  17. Phosphorylation of Titin Modulates Passive Stiffness of Cardiac Muscle in a Titin Isoform-dependent Manner

    OpenAIRE

    Fukuda, Norio; Wu, Yiming; Nair, Preetha; Granzier, Henk L.

    2005-01-01

    We investigated the effect of protein kinase A (PKA) on passive force in skinned cardiac tissues that express different isoforms of titin, i.e., stiff (N2B) and more compliant (N2BA) titins, at different levels. We used rat ventricular (RV), bovine left ventricular (BLV), and bovine left atrial (BLA) muscles (passive force: RV > BLV > BLA, with the ratio of N2B to N2BA titin, ∼90:10, ∼40:60, and ∼10:90%, respectively) and found that N2B and N2BA isoforms can both be phosphorylated by PKA. Und...

  18. Structural and Functional Characterization of Recombinant Isoforms of the Lentil Lipid Transfer Protein

    OpenAIRE

    Bogdanov, I. V.; Finkina, E. I.; Balandin, S. V.; Melnikova, D. N.; Stukacheva, E. A.; Ovchinnikova, T. V.

    2015-01-01

    The recombinant isoforms Lc-LTP1 and Lc-LTP3 of the lentil lipid transfer protein were overexpressed in E. coli cells. It was confirmed that both proteins are stabilized by four disulfide bonds and characterized by a high proportion of the α-helical structure. It was found that Lc-LTP1 and Lc-LTP3 possess antimicrobial activity and can bind fatty acids. Both isoforms have the ability to bind specific IgE from sera of patients with food allergies, which recognize similar epitopes of the major ...

  19. STRUCTURAL AND FUNCTIONAL CHARACTERIZATION OF RECOMBINANT ISOFORMS OF THE LENTIL LIPID TRANSFER PROTEIN

    OpenAIRE

    Bogdanov, I. V.; Finkina, E. I.; Balandin, S. V.; Melnikova, D. N.; Stukacheva, E. A.; Ovchinnikova, T. V.

    2015-01-01

    The recombinant isoforms Lc-LTP1 and Lc-LTP3 of the lentil lipid transfer protein were overexpressed in E. coli cells. It was confirmed that both proteins are stabilized by four disulfide bonds and characterized by a high proportion of the α-helical structure. It was found that Lc-LTP1 and Lc-LTP3 possess antimicrobial activity and can bind fatty acids. Both isoforms have the ability to bind specific IgE from sera of patients with food allergies, which recognize similar epitopes of the major ...

  20. Lipoprotein(a) concentrations, isoform size, and risk of type 2 diabetes

    DEFF Research Database (Denmark)

    Kamstrup, Pia Rørbæk; Nordestgaard, Børge

    2013-01-01

    study to investigate whether large isoform size, low concentrations in plasma, or both, are causally associated with type 2 diabetes. METHODS: We assessed data for adults from the Danish general population enrolled in the Copenhagen City Heart Study and the Copenhagen General Population Study, with and......(a) concentrations alone seem not to be causally associated with type 2 diabetes, but a causal association for large lipoprotein(a) isoform size cannot be excluded. FUNDING: Danish Heart Foundation, Danish Council for Independent Research-Medical Sciences, IMK Almene Fund, and Johan and Lise Boserup's Fund....

  1. Lipoprotein(a) levels, isoform size, and risk of type 2 diabetes: A Mendelian randomisation study

    DEFF Research Database (Denmark)

    Kamstrup, Pia Rørbæk; Nordestgaard, Børge G.

    2013-01-01

    study to investigate whether large isoform size, low concentrations in plasma, or both, are causally associated with type 2 diabetes. Methods: We assessed data for adults from the Danish general population enrolled in the Copenhagen City Heart Study and the Copenhagen General Population Study, with and......(a) concentrations alone seem not to be causally associated with type 2 diabetes, but a causal association for large lipoprotein(a) isoform size cannot be excluded. Funding: Danish Heart Foundation, Danish Council for Independent Research-Medical Sciences, IMK Almene Fund, and Johan and Lise Boserup's Fund....

  2. VEGF121b and VEGF165b are weakly angiogenic isoforms of VEGF-A

    Directory of Open Access Journals (Sweden)

    Pio Ruben

    2010-12-01

    Full Text Available Abstract Background Different isoforms of VEGF-A (mainly VEGF121, VEGF165 and VEGF189 have been shown to display particular angiogenic properties in the generation of a functional tumor vasculature. Recently, a novel class of VEGF-A isoforms, designated as VEGFxxxb, generated through alternative splicing, have been described. Previous studies have suggested that these isoforms may inhibit angiogenesis. In the present work we have produced recombinant VEGF121/165b proteins in the yeast Pichia pastoris and constructed vectors to overexpress these isoforms and assess their angiogenic potential. Results Recombinant VEGF121/165b proteins generated either in yeasts or mammalian cells activated VEGFR2 and its downstream effector ERK1/2, although to a lesser extent than VEGF165. Furthermore, treatment of endothelial cells with VEGF121/165b increased cell proliferation compared to untreated cells, although such stimulation was lower than that induced by VEGF165. Moreover, in vivo angiogenesis assays confirmed angiogenesis stimulation by VEGF121/165b isoforms. A549 and PC-3 cells overexpressing VEGF121b or VEGF165b (or carrying the PCDNA3.1 empty vector, as control and xenotransplanted into nude mice showed increased tumor volume and angiogenesis compared to controls. To assess whether the VEGFxxxb isoforms are differentially expressed in tumors compared to healthy tissues, immunohistochemical analysis was conducted on a breast cancer tissue microarray. A significant increase (p xxxb and total VEGF-A protein expression in infiltrating ductal carcinomas compared to normal breasts was observed. A positive significant correlation (r = 0.404, p = 0.033 between VEGFxxxb and total VEGF-A was found. Conclusions Our results demonstrate that VEGF121/165b are not anti-angiogenic, but weakly angiogenic isoforms of VEGF-A. In addition, VEGFxxxb isoforms are up-regulated in breast cancer in comparison with non malignant breast tissues. These results are to be taken

  3. Progesterone receptor isoform A may regulate the effects of neoadjuvant aglepristone in canine mammary carcinoma

    DEFF Research Database (Denmark)

    Guil-Luna, Silvia; Stenvang, Jan; Brünner, Nils;

    2014-01-01

    and mRNA expression of progesterone receptor isoforms A and B in mammary carcinomas in dogs treated with 20 mg/Kg of aglepristone (n¿=¿22) or vehicle (n¿=¿5) twice before surgery.ResultsFormalin-fixed, paraffin-embedded tissue samples taken before and after treatment were used to analyse total......BackgroundProgesterone receptors play a key role in the development of canine mammary tumours, and recent research has focussed on their possible value as therapeutic targets using antiprogestins. Cloning and sequencing of the progesterone receptor gene has shown that the receptor has two isoforms...

  4. Each Individual Isoform of the Dopamine D2 Receptor Protects from Lactotroph Hyperplasia

    OpenAIRE

    Radl, Daniela; De Mei, Claudia; Chen, Eric; Lee, Hyuna; Borrelli, Emiliana

    2013-01-01

    Dopamine acting through D2 receptors (D2Rs) controls lactotroph proliferation and prolactin (PRL) levels. Ablation of this receptor in mice results in lactotroph hyperplasia and prolactinomas in aged females. Alternative splicing of the Drd2 gene generates 2 independent isoforms, a long (D2L) and a short (D2S) isoform, which are present in all D2R-expressing cells. Here, we addressed the role of D2L and D2S on lactotroph physiology through the generation and analysis of D2S-null mice and thei...

  5. Role of Sec24 isoforms in selective export of membrane proteins from the endoplasmic reticulum

    OpenAIRE

    Wendeler, Markus W; Paccaud, Jean-Pierre; Hauri, Hans-Peter

    2007-01-01

    Sec24 of the COPII (coat protein complex II) vesicle coat mediates the selective export of membrane proteins from the endoplasmic reticulum (ER) in yeast. Human cells express four Sec24 isoforms, but their role is unknown. Here, we report the differential effects of Sec24 isoform-specific silencing on the transport of the membrane reporter protein ERGIC-53 (ER–Golgi intermediate compartment-53) carrying the cytosolic ER export signals di-phenylalanine, di-tyrosine, di-leucine, di-isoleucine, ...

  6. Glucocorticoid receptor translational isoforms underlie maturational stage-specific glucocorticoid sensitivities of dendritic cells in mice and humans.

    Science.gov (United States)

    Cao, Yun; Bender, Ingrid K; Konstantinidis, Athanasios K; Shin, Soon Cheon; Jewell, Christine M; Cidlowski, John A; Schleimer, Robert P; Lu, Nick Z

    2013-02-28

    Although glucocorticoids are a profoundly important class of anti-inflammatory and immunosuppressive agents, their actions in dendritic cells (DCs) are not well understood. We found that dexamethasone, a potent glucocorticoid, selectively induced apoptosis in mature, but not in immature, DCs in healthy mice, in mice with experimental airway inflammation, and in vitro in bone marrow–derived DCs. Distinct glucocorticoid receptor (GR) translational isoforms expressed in immature and mature DCs probably contribute to the DC maturational stage-specific glucocorticoid sensitivity. The GR-D isoforms were the predominant isoforms in immature DCs, whereas the proapoptotic GR-A isoform was the main isoform in mature DCs. Ectopic expression of the GR-A isoform in immature DCs increased glucocorticoid sensitivity and RU486, a selective GR antagonist, inhibited the glucocorticoid sensitivity of mature DCs. Furthermore, the distinct expression pattern of GR isoforms in immature and mature murine DCs was also observed in human monocyte–derived DCs. These studies suggest that glucocorticoids may spare immature DCs and suppress mature DCs and inflammation via differential expression of GR translational isoforms. PMID:23297131

  7. Sulfonamides incorporating heteropolycyclic scaffolds show potent inhibitory action against carbonic anhydrase isoforms I, II, IX and XII.

    Science.gov (United States)

    Barresi, Elisabetta; Salerno, Silvia; Marini, Anna Maria; Taliani, Sabrina; La Motta, Concettina; Simorini, Francesca; Da Settimo, Federico; Vullo, Daniela; Supuran, Claudiu T

    2016-02-15

    Three series of polycyclic compounds possessing either primary sulfonamide or carboxylic acid moieties as zinc-binding groups were investigated as inhibitors of four physiologically relevant CA isoforms, the cytosolic hCA I and II, as well as the transmembrane hCA IX and XII. Most of the new sulfonamides reported here showed excellent inhibitory effects against isoforms hCA II, IX and XII, but no highly isoform-selective inhibition profiles. On the other hand, the carboxylates selectively inhibited hCA IX (KIs ranging between 40.8 and 92.7nM) without inhibiting significantly the other isoforms. Sulfonamides/carboxylates incorporating polycyclic ring systems such as benzothiopyranopyrimidine, pyridothiopyranopyrimidine or dihydrobenzothiopyrano[4,3-c]pyrazole may be considered as interesting candidates for exploring the design of isoform-selective CAIs with various pharmacologic applications. PMID:26796953

  8. Inter-isoform-dependent Regulation of the Drosophila Master Transcriptional Regulator SIN3.

    Science.gov (United States)

    Chaubal, Ashlesha; Todi, Sokol V; Pile, Lori A

    2016-05-27

    SIN3 is a transcriptional corepressor that acts as a scaffold for a histone deacetylase (HDAC) complex. The SIN3 complex regulates various biological processes, including organ development, cell proliferation, and energy metabolism. Little is known, however, about the regulation of SIN3 itself. There are two major isoforms of Drosophila SIN3, 187 and 220, which are differentially expressed. Intrigued by the developmentally timed exchange of SIN3 isoforms, we examined whether SIN3 187 controls the fate of the 220 counterpart. Here, we show that in developing tissue, there is interplay between SIN3 isoforms: when SIN3 187 protein levels increase, SIN3 220 protein decreases concomitantly. SIN3 187 has a dual effect on SIN3 220. Expression of 187 leads to reduced 220 transcript, while also increasing the turnover of SIN3 220 protein by the proteasome. These data support the presence of a novel, inter-isoform-dependent mechanism that regulates the amount of SIN3 protein, and potentially the level of specific SIN3 complexes, during distinct developmental stages. PMID:27129248

  9. Neural cell adhesion molecule differentially interacts with isoforms of the fibroblast growth factor receptor

    DEFF Research Database (Denmark)

    Christensen, Claus; Berezin, Vladimir; Bock, Elisabeth

    2011-01-01

    The fibroblast growth factor receptor (FGFR) can be activated through direct interactions with various fibroblast growth factors or through a number of cell adhesion molecules, including the neural cell adhesion molecule (NCAM). We produced recombinant proteins comprising the ligand...... the expression pattern of various FGFR isoforms determines the cell context-specific effects of NCAM signaling through FGFR....

  10. The activity and isoforms of NADP-malic enzyme in Nicotiana benthamiana plants under biotic stress

    Czech Academy of Sciences Publication Activity Database

    Doubnerová, V.; Jirásková, A.; Janošková, M.; Müller, Karel; Baťková, Petra; Synková, Helena; Čeřovská, Noemi; Ryšlavá, H.

    2007-01-01

    Roč. 26, č. 4 (2007), s. 281-289. ISSN 0231-5882 Institutional research plan: CEZ:AV0Z50380511 Keywords : NADP * malic enzyme isoforms * Nicotiana benthamiana Subject RIV: EF - Botanics Impact factor: 1.286, year: 2007 http://www.gpb.sav.sk/2007-4.htm

  11. Subcellular targeting of nine calcium-dependent protein kinase isoforms from Arabidopsis

    Science.gov (United States)

    Dammann, Christian; Ichida, Audrey; Hong, Bimei; Romanowsky, Shawn M.; Hrabak, Estelle M.; Harmon, Alice C.; Pickard, Barbara G.; Harper, Jeffrey F.; Evans, M. L. (Principal Investigator)

    2003-01-01

    Calcium-dependent protein kinases (CDPKs) are specific to plants and some protists. Their activation by calcium makes them important switches for the transduction of intracellular calcium signals. Here, we identify the subcellular targeting potentials for nine CDPK isoforms from Arabidopsis, as determined by expression of green fluorescent protein (GFP) fusions in transgenic plants. Subcellular locations were determined by fluorescence microscopy in cells near the root tip. Isoforms AtCPK3-GFP and AtCPK4-GFP showed a nuclear and cytosolic distribution similar to that of free GFP. Membrane fractionation experiments confirmed that these isoforms were primarily soluble. A membrane association was observed for AtCPKs 1, 7, 8, 9, 16, 21, and 28, based on imaging and membrane fractionation experiments. This correlates with the presence of potential N-terminal acylation sites, consistent with acylation as an important factor in membrane association. All but one of the membrane-associated isoforms targeted exclusively to the plasma membrane. The exception was AtCPK1-GFP, which targeted to peroxisomes, as determined by covisualization with a peroxisome marker. Peroxisome targeting of AtCPK1-GFP was disrupted by a deletion of two potential N-terminal acylation sites. The observation of a peroxisome-located CDPK suggests a mechanism for calcium regulation of peroxisomal functions involved in oxidative stress and lipid metabolism.

  12. Synthesis of Benzofuran Analogue of Go6976, an Isoform Selective Protein Kinase C Inhibitor

    Institute of Scientific and Technical Information of China (English)

    MA, Da-Wei; ZHANG, Xin-Rong; WU, Shi-Hui; TAO, Feng-Gang

    2001-01-01

    Based on the structure of Go6976, a known isoform-selective protein kinase C inhibitor, a benzofuran analogue (1) was designed. This analogue was synthesized by coupling of benzofuran 3-acetic acid and 8-oxo-tryptamine and subsequent intramolecular Dieckmann condensation, alkylation, oxidative photocyclization and cyanation reaction of mesylate.

  13. Both Myosin-10 isoforms are required for radial neuronal migration in the developing cerebral cortex.

    Science.gov (United States)

    Ju, Xing-Da; Guo, Ye; Wang, Nan-Nan; Huang, Ying; Lai, Ming-Ming; Zhai, Yan-Hua; Guo, Yu-Guang; Zhang, Jian-Hua; Cao, Rang-Juan; Yu, Hua-Li; Cui, Lei; Li, Yu-Ting; Wang, Xing-Zhi; Ding, Yu-Qiang; Zhu, Xiao-Juan

    2014-05-01

    During embryonic development of the mammalian cerebral cortex, postmitotic cortical neurons migrate radially from the ventricular zone to the cortical plate. Proper migration involves the correct orientation of migrating neurons and the transition from a multipolar to a mature bipolar morphology. Herein, we report that the 2 isoforms of Myosin-10 (Myo10) play distinct roles in the regulation of radial migration in the mouse cortex. We show that the full-length Myo10 (fMyo10) isoform is located in deeper layers of the cortex and is involved in establishing proper migration orientation. We also demonstrate that fMyo10-dependent orientation of radial migration is mediated at least in part by the netrin-1 receptor deleted in colorectal cancer. Moreover, we show that the headless Myo10 (hMyo10) isoform is required for the transition from multipolar to bipolar morphologies in the intermediate zone. Our study reveals divergent functions for the 2 Myo10 isoforms in controlling both the direction of migration and neuronal morphogenesis during radial cortical neuronal migration. PMID:23300110

  14. A mitotic SKAP isoform regulates spindle positioning at astral microtubule plus ends.

    Science.gov (United States)

    Kern, David M; Nicholls, Peter K; Page, David C; Cheeseman, Iain M

    2016-05-01

    The Astrin/SKAP complex plays important roles in mitotic chromosome alignment and centrosome integrity, but previous work found conflicting results for SKAP function. Here, we demonstrate that SKAP is expressed as two distinct isoforms in mammals: a longer, testis-specific isoform that was used for the previous studies in mitotic cells and a novel, shorter mitotic isoform. Unlike the long isoform, short SKAP rescues SKAP depletion in mitosis and displays robust microtubule plus-end tracking, including localization to astral microtubules. Eliminating SKAP microtubule binding results in severe chromosome segregation defects. In contrast, SKAP mutants specifically defective for plus-end tracking facilitate proper chromosome segregation but display spindle positioning defects. Cells lacking SKAP plus-end tracking have reduced Clasp1 localization at microtubule plus ends and display increased lateral microtubule contacts with the cell cortex, which we propose results in unbalanced dynein-dependent cortical pulling forces. Our work reveals an unappreciated role for the Astrin/SKAP complex as an astral microtubule mediator of mitotic spindle positioning. PMID:27138257

  15. Improved mass spectrometry assay for plasma hepcidin: detection and characterization of a novel hepcidin isoform

    NARCIS (Netherlands)

    Laarakkers, C.M.; Wiegerinck, E.T.G.; Klaver, S.; Kolodziejczyk, M.; Gille, H.; Hohlbaum, A.M.; Tjalsma, H.; Swinkels, D.W.

    2013-01-01

    Mass spectrometry (MS)-based assays for the quantification of the iron regulatory hormone hepcidin are pivotal to discriminate between the bioactive 25-amino acid form that can effectively block the sole iron transporter ferroportin and other naturally occurring smaller isoforms without a known role

  16. Purification and catalytic properties of polygalacturonase isoforms from ripe avocado (Persea americana) fruit mesocarp.

    Science.gov (United States)

    Wakabayashi, Kazuyuki; Huber, Donald J.

    2001-10-01

    Endo-polygalacturonase (PG; EC 3.2.1.15) was recovered from the cell walls of avocado mesocarp (Persea americana Mill cv. Lula) tissue and purified by sequential ion exchange and gel permeation chromatography. Two isoforms (S-I and S-II) were recovered, exhibiting molecular masses of about 41 kD on size exclusion media and about 48 (S-I) and 46 (S-II) kDa as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Both isoforms exhibited maximum activity at pH 6.0 against polygalacturonic acid (PGA) and hydrolyzed PGA of about 180 kDa to polymers of about 4 kDa. The catalytic activity of the 48-kDa isoform against PGA was slightly higher than that of the 46-kDa isoform. The purified PGs catalyzed significant molecular mass downshifts in the polyuronides of pre-ripe avocados; however, the capacity of the enzymes to solubilize polyuronides from cell walls of pre-ripe fruit was limited. PMID:12060298

  17. Antitumor effects in hepatocarcinoma of isoform-selective inhibition of HDAC2

    DEFF Research Database (Denmark)

    Lee, Yun-Han; Seo, Daekwan; Choi, Kyung-Ju;

    2014-01-01

    Histone deacetylase 2 (HDAC2) is a chromatin modifier involved in epigenetic regulation of cell cycle, apoptosis and differentiation that is upregulated commonly in human hepatocellular carcinoma (HCC). In this study, we show that specific targeting of this HDAC isoform is sufficient to inhibit H...

  18. Branchial Expression Patterns of Claudin Isoforms in Atlantic Salmon During Seawater Acclimation and Smoltification

    DEFF Research Database (Denmark)

    Tipsmark, Christian K; Kiilerich, Pia; Nilsen, Tom O;

    2008-01-01

    epithelia. We identified Atlantic salmon genes belonging to the claudin family by screening expressed sequence tag libraries available at NCBI and classification was performed with aid of maximum likelihood and neighbour-joining analysis. In gill libraries, five isoforms (10e, 27a, 28a, 28b and 30) were...

  19. Identification of a novel CoA synthase isoform, which is primarily expressed in Brain

    International Nuclear Information System (INIS)

    CoA and its derivatives Acetyl-CoA and Acyl-CoA are important players in cellular metabolism and signal transduction. CoA synthase is a bifunctional enzyme which mediates the final stages of CoA biosynthesis. In previous studies, we have reported molecular cloning, biochemical characterization, and subcellular localization of CoA synthase (CoASy). Here, we describe the existence of a novel CoA synthase isoform, which is the product of alternative splicing and possesses a 29aa extension at the N-terminus. We termed it CoASy β and originally identified CoA synthase, CoASy α. The transcript specific for CoASy β was identified by electronic screening and by RT-PCR analysis of various rat tissues. The existence of this novel isoform was further confirmed by immunoblot analysis with antibodies directed to the N-terminal peptide of CoASy β. In contrast to CoASy α, which shows ubiquitous expression, CoASy β is primarily expressed in Brain. Using confocal microscopy, we demonstrated that both isoforms are localized on mitochondria. The N-terminal extension does not affect the activity of CoA synthase, but possesses a proline-rich sequence which can bring the enzyme into complexes with signalling proteins containing SH3 or WW domains. The role of this novel isoform in CoA biosynthesis, especially in Brain, requires further elucidation

  20. Heparanase isoform expression and extracellular matrix remodeling in intervertebral disc degenerative disease

    Directory of Open Access Journals (Sweden)

    Luciano Miller Reis Rodrigues

    2011-01-01

    Full Text Available OBJECTIVE: To determine the molecules involved in extracellular matrix remodeling and to identify and quantify heparanase isoforms present in herniated and degenerative discs. INTRODUCTION: Heparanase is an endo-beta-glucuronidase that specifically acts upon the heparan sulfate chains of proteoglycans. However, heparanase expression in degenerative intervertebral discs has not yet been evaluated. Notably, previous studies demonstrated a correlation between changes in the heparan sulfate proteoglycan pattern and the degenerative process associated with intervertebral discs. METHODS: Twenty-nine samples of intervertebral degenerative discs, 23 samples of herniated discs and 12 samples of non-degenerative discs were analyzed. The expression of both heparanase isoforms (heparanase-1 and heparanase-2 was evaluated using immunohistochemistry and real-time RT-PCR analysis. RESULTS: Heparanase-1 and heparanase-2 expression levels were significantly higher in the herniated and degenerative discs in comparison to the control tissues, suggesting a possible role of these proteins in the intervertebral degenerative process. CONCLUSION: The overexpression of heparanase isoforms in the degenerative intervertebral discs and the herniated discs suggests a potential role of both proteins in the mediation of inflammatory processes and in extracellular matrix remodeling. The heparanase-2 isoform may be involved in normal metabolic processes, as evidenced by its higher expression in the control intervertebral discs relative to the expression of heparanase-1.

  1. Novel Kidins220/ARMS Splice Isoforms: Potential Specific Regulators of Neuronal and Cardiovascular Development.

    Directory of Open Access Journals (Sweden)

    Nathalie Schmieg

    Full Text Available Kidins220/ARMS is a transmembrane protein playing a crucial role in neuronal and cardiovascular development. Kidins220/ARMS is a downstream target of neurotrophin receptors and interacts with several signalling and trafficking factors. Through computational modelling, we found two potential sites for alternative splicing of Kidins220/ARMS. The first is located between exon 24 and exon 29, while the second site replaces exon 32 by a short alternative terminal exon 33. Here we describe the conserved occurrence of several Kidins220/ARMS splice isoforms at RNA and protein levels. Kidins220/ARMS splice isoforms display spatio-temporal regulation during development with distinct patterns in different neuronal populations. Neurotrophin receptor stimulation in cortical and hippocampal neurons and neuroendocrine cells induces specific Kidins220/ARMS splice isoforms and alters the appearance kinetics of the full-length transcript. Remarkably, alternative terminal exon splicing generates Kidins220/ARMS variants with distinct cellular localisation: Kidins220/ARMS containing exon 32 is targeted to the plasma membrane and neurite tips, whereas Kidins220/ARMS without exon 33 mainly clusters the full-length protein in a perinuclear intracellular compartment in PC12 cells and primary neurons, leading to a change in neurotrophin receptor expression. Overall, this study demonstrates the existence of novel Kidins220/ARMS splice isoforms with unique properties, revealing additional complexity in the functional regulation of neurotrophin receptors, and potentially other signalling pathways involved in neuronal and cardiovascular development.

  2. The Invasion and Metastasis Promotion Role of CD97 Small Isoform in Gastric Carcinoma

    DEFF Research Database (Denmark)

    Liu, Daren; Trojanowicz, Bogusz; Ye, Longyun; Li, Chao; Zhang, Luqing; Li, Xiaowen; Li, Guogang; Zheng, Yixiong; Chen, Li

    2012-01-01

    metastatic regional lymph nodes on post-operative day 42 was distinctly decreased in the CD97/EGF1,2,5kd group as compared with the SGC-NS group, and was accompanied with the downregulation of CD44, VEGFR, CD31 and CD97. We concluded in this study that CD97 small isoform not only supported gastric cancer...

  3. Quarternary structure and enzymological properties of the different hormone-sensitive lipase (HSL) isoforms

    DEFF Research Database (Denmark)

    Krintel, Christian; Klint, Cecilia; Lindvall, Håkan; Mörgelin, Matthias; Holm, Cecilia

    2010-01-01

    Hormone-sensitive lipase (HSL) is a key enzyme in the mobilization of energy in the form of fatty acids from intracellular stores of neutral lipids. The enzyme has been shown to exist in different isoforms with different molecular masses (84 kDa, 89 kDa and 117 kDa) expressed in a tissue...

  4. Over-expression in Escherichia coli and characterization of two recombinant isoforms of human FAD synthetase

    International Nuclear Information System (INIS)

    FAD synthetase (FADS) (EC 2.7.7.2) is a key enzyme in the metabolic pathway that converts riboflavin into the redox cofactor FAD. Two hypothetical human FADSs, which are the products of FLAD1 gene, were over-expressed in Escherichia coli and identified by ESI-MS/MS. Isoform 1 was over-expressed as a T7-tagged protein which had a molecular mass of 63 kDa on SDS-PAGE. Isoform 2 was over-expressed as a 6-His-tagged fusion protein, carrying an extra 84 amino acids at the N-terminal with an apparent molecular mass of 60 kDa on SDS-PAGE. It was purified near to homogeneity from the soluble cell fraction by one-step affinity chromatography. Both isoforms possessed FADS activity and had a strict requirement for MgCl2, as demonstrated using both spectrophotometric and chromatographic methods. The purified recombinant isoform 2 showed a specific activity of 6.8 ± 1.3 nmol of FAD synthesized/min/mg protein and exhibited a K M value for FMN of 1.5 ± 0.3 μM. This is First report on characterization of human FADS, and First cloning and over-expression of FADS from an organism higher than yeast

  5. A mutation in a skin-specific isoform of SMARCAD1 causes autosomal-dominant adermatoglyphia.

    Science.gov (United States)

    Nousbeck, Janna; Burger, Bettina; Fuchs-Telem, Dana; Pavlovsky, Mor; Fenig, Shlomit; Sarig, Ofer; Itin, Peter; Sprecher, Eli

    2011-08-12

    Monogenic disorders offer unique opportunities for researchers to shed light upon fundamental physiological processes in humans. We investigated a large family affected with autosomal-dominant adermatoglyphia (absence of fingerprints) also known as the "immigration delay disease." Using linkage and haplotype analyses, we mapped the disease phenotype to 4q22. One of the genes located in this interval is SMARCAD1, a member of the SNF subfamily of the helicase protein superfamily. We demonstrated the existence of a short isoform of SMARCAD1 exclusively expressed in the skin. Sequencing of all SMARCAD1 coding and noncoding exons revealed a heterozygous transversion predicted to disrupt a conserved donor splice site adjacent to the 3' end of a noncoding exon uniquely present in the skin-specific short isoform of the gene. This mutation segregated with the disease phenotype throughout the entire family. Using a minigene system, we found that this mutation causes aberrant splicing, resulting in decreased stability of the short RNA isoform as predicted by computational analysis and shown by RT-PCR. Taken together, the present findings implicate a skin-specific isoform of SMARCAD1 in the regulation of dermatoglyph development. PMID:21820097

  6. A novel MCPH1 isoform complements the defective chromosome condensation of human MCPH1-deficient cells.

    Directory of Open Access Journals (Sweden)

    Ioannis Gavvovidis

    Full Text Available Biallelic mutations in MCPH1 cause primary microcephaly (MCPH with the cellular phenotype of defective chromosome condensation. MCPH1 encodes a multifunctional protein that notably is involved in brain development, regulation of chromosome condensation, and DNA damage response. In the present studies, we detected that MCPH1 encodes several distinct transcripts, including two major forms: full-length MCPH1 (MCPH1-FL and a second transcript lacking the six 3' exons (MCPH1Δe9-14. Both variants show comparable tissue-specific expression patterns, demonstrate nuclear localization that is mediated independently via separate NLS motifs, and are more abundant in certain fetal than adult organs. In addition, the expression of either isoform complements the chromosome condensation defect found in genetically MCPH1-deficient or MCPH1 siRNA-depleted cells, demonstrating a redundancy of both MCPH1 isoforms for the regulation of chromosome condensation. Strikingly however, both transcripts are regulated antagonistically during cell-cycle progression and there are functional differences between the isoforms with regard to the DNA damage response; MCPH1-FL localizes to phosphorylated H2AX repair foci following ionizing irradiation, while MCPH1Δe9-14 was evenly distributed in the nucleus. In summary, our results demonstrate here that MCPH1 encodes different isoforms that are differentially regulated at the transcript level and have different functions at the protein level.

  7. The Drosophila pumilio gene encodes two functional protein isoforms that play multiple roles in germline development, gonadogenesis, oogenesis and embryogenesis.

    Science.gov (United States)

    Parisi, M; Lin, H

    1999-01-01

    The pumilio (pum) gene plays an essential role in embryonic patterning and germline stem cell (GSC) maintenance during oogenesis in Drosophila. Here we report on a phenotypic analysis using pum(ovarette) mutations, which reveals multiple functions of pum in primordial germ cell proliferation, larval ovary formation, GSC division, and subsequent oogenic processes, as well as in oviposition. Specifically, by inducing pum(-) GSC clones at the onset of oogenesis, we show that pum is directly involved in GSC division, a function that is distinct from its requirement in primordial germ cells. Furthermore, we show that pum encodes 156- and 130-kD proteins, both of which are functional isoforms. Among pum(ovarette) mutations, pum(1688) specifically eliminates the 156-kD isoform but not the 130-kD isoform, while pum(2003) and pum(4277) specifically affect the 130-kD isoform but not the 156-kD isoform. Normal doses of both isoforms are required for the zygotic function of pum, yet either isoform alone at a normal dose is sufficient for the maternal effect function of pum. A pum cDNA transgene that contains the known open reading frame encodes only the 156-kD isoform and rescues the phenotype of both pum(1688) and pum(2003) mutants. These observations suggest that the 156- and 130-kD isoforms can compensate for each other's function in a dosage-dependent manner. Finally, we present molecular evidence suggesting that the two PUM isoforms share some of their primary structures. PMID:10471709

  8. Selective expression of myosin IC Isoform A in mouse and human cell lines and mouse prostate cancer tissues.

    Directory of Open Access Journals (Sweden)

    Ivanna Ihnatovych

    Full Text Available Myosin IC is a single headed member of the myosin superfamily. We recently identified a novel isoform and showed that the MYOIC gene in mammalian cells encodes three isoforms (isoforms A, B, and C. Furthermore, we demonstrated that myosin IC isoform A but not isoform B exhibits a tissue specific expression pattern. In this study, we extended our analysis of myosin IC isoform expression patterns by analyzing the protein and mRNA expression in various mammalian cell lines and in various prostate specimens and tumor tissues from the transgenic mouse prostate (TRAMP model by immunoblotting, qRT-PCR, and by indirect immunohistochemical staining of paraffin embedded prostate specimen. Analysis of a panel of mammalian cell lines showed an increased mRNA and protein expression of specifically myosin IC isoform A in a panel of human and mouse prostate cancer cell lines but not in non-cancer prostate or other (non-prostate- cancer cell lines. Furthermore, we demonstrate that myosin IC isoform A expression is significantly increased in TRAMP mouse prostate samples with prostatic intraepithelial neoplasia (PIN lesions and in distant site metastases in lung and liver when compared to matched normal tissues. Our observations demonstrate specific changes in the expression of myosin IC isoform A that are concurrent with the occurrence of prostate cancer in the TRAMP mouse prostate cancer model that closely mimics clinical prostate cancer. These data suggest that elevated levels of myosin IC isoform A may be a potential marker for the detection of prostate cancer.

  9. Conformational difference in human IgG2 disulfide isoforms revealed by hydrogen/deuterium exchange mass spectrometry.

    Science.gov (United States)

    Zhang, Aming; Fang, Jing; Chou, Robert Y-T; Bondarenko, Pavel V; Zhang, Zhongqi

    2015-03-17

    Both recombinant and natural human IgG2 antibodies have several different disulfide bond isoforms, which possess different global structures, thermal stabilities, and biological activities. A detailed mapping of the structural difference among IgG2 disulfide isoforms, however, has not been established. In this work, we employed hydrogen/deuterium exchange mass spectrometry to study the conformation of three major IgG2 disulfide isoforms known as IgG2-B, IgG2-A1, and IgG2-A2 in two recombinant human IgG2 monoclonal antibodies. By comparing the protection factors between amino acid residues in isoforms B and A1 (the classical form), we successfully identified several local regions in which the IgG2-B isoform showed more solvent protection than the IgG2-A1 isoform. On the basis of three-dimensional structural models of IgG2, these identified regions were located on the Fab domains, close to the hinge, centered on the side where the two Fab arms faced each other in spatial proximity. We speculated that in the more solvent-protected B isoform, the two Fab arms were brought into contact by the nonclassical disulfide bonds, resulting in a more compact global structure. Loss of Fab domain flexibility in IgG2-B could limit its ability to access cell-surface epitopes, leading to reduced antigen binding potency. The A2 isoform was previously found to have disulfide linkages similar to those of the classical A1 isoform, but with different biophysical behaviors. Our data indicated that, compared to IgG2-A1, IgG2-A2 had less solvent protection in some heavy-chain Fab regions close the hinge, suggesting that the A2 isoform had more flexible Fab domains. PMID:25730439

  10. Two Distinct Isoforms of Matrix Metalloproteinase-2 Are Associated with Human Delayed Kidney Graft Function.

    Directory of Open Access Journals (Sweden)

    Shaynah Wanga

    Full Text Available Delayed graft function (DGF is a frequent complication of renal transplantation, particularly in the setting of transplantation of kidneys derived from deceased donors and expanded-criteria donors. DGF results from tubular epithelial cell injury and has immediate and long term consequences. These include requirement for post-transplantation dialysis, increased incidence of acute rejection, and poorer long-term outcomes. DGF represents one of the clearest clinical examples of renal acute ischemia/reperfusion injury. Experimental studies have demonstrated that ischemia/reperfusion injury induces the synthesis of the full length secreted isoform of matrix metalloproteinase-2 (FL-MMP-2, as well as an intracellular N-terminal truncated MMP-2 isoform (NTT-MMP-2 that initiates an innate immune response. We hypothesized that the two MMP-2 isoforms mediate tubular epithelial cell injury in DGF. Archival renal biopsy sections from 10 protocol biopsy controls and 41 cases with a clinical diagnosis of DGF were analyzed for the extent of tubular injury, expression of the FL-MMP-2 and NTT-MMP-2 isoforms by immunohistochemistry (IHC, in situ hybridization, and qPCR to determine isoform abundance. Differences in transcript abundance were related to tubular injury score. Markers of MMP-2-mediated injury included TUNEL staining and assessment of peritubular capillary density. There was a clear relationship between tubular epithelial cell expression of both FL-MMP-2 and NTT-MMP-2 IHC with the extent of tubular injury. The MMP-2 isoforms were detected in the same tubular segments and were present at sites of tubular injury. qPCR demonstrated highly significant increases in both the FL-MMP-2 and NTT-MMP-2 transcripts. Statistical analysis revealed highly significant associations between FL-MMP-2 and NTT-MMP-2 transcript abundance and the extent of tubular injury, with NTT-MMP-2 having the strongest association. We conclude that two distinct MMP-2 isoforms are

  11. Kalrn promoter usage and isoform expression respond to chronic cocaine exposure

    Directory of Open Access Journals (Sweden)

    Ma Xin-Ming

    2011-02-01

    Full Text Available Abstract Background The long-term effects of cocaine on behavior are accompanied by structural changes in excitatory glutamatergic synapses onto the medium spiny neurons of the striatum. The Kalrn gene encodes several functionally distinct isoforms; these multidomain guanine nucleotide exchange factors (GEFs contain additional domains known to interact with phosphatidylinositides as well as with a number of different proteins. Through their activation of Rho proteins and their interactions with other proteins, the different Kalirin isoforms affect cytoskeletal organization. Chronic exposure of adult male rodents to cocaine increases levels of Kalirin 7 in the striatum. When exposed chronically to cocaine, mice lacking Kalirin 7, the major adult isoform, fail to show an increase in dendritic spine density in the nucleus accumbens, show diminished place preference for cocaine, and exhibit increased locomotor activity in response to cocaine. Results The use of alternate promoters and 3'-terminal exons of the mouse Kalrn gene were investigated using real-time quantitative polymerase chain reaction. While the two most distal full-length Kalrn promoters are used equally in the prefrontal cortex, the more proximal of these promoters accounts for most of the transcripts expressed in the nucleus accumbens. The 3'-terminal exon unique to the Kalirin 7 isoform accounts for a greater percentage of the Kalrn transcripts in prefrontal cortex than in nucleus accumbens. Western blot analyses confirmed these differences. Chronic cocaine treatment increases usage of the promoter encoding the Δ-Kalirin isoforms but does not alter full-length Kalirin promoter usage. Usage of the 3'-terminal exon unique to Kalirin 7 increases following chronic cocaine exposure. Conclusions Kalrn promoter and 3'-terminal exon utilization are region-specific. In the nucleus accumbens, cocaine-mediated alterations in promoter usage and 3'-terminal exon usage favor expression of

  12. Changes in type II procollagen isoform expression during chondrogenesis by disruption of an alternative 5’ splice site within Col2a1 exon 2

    OpenAIRE

    Hering, Thomas M.; Wirthlin, Louisa; Ravindran, Soumya; McAlinden, Audrey

    2014-01-01

    This study describes a new mechanism controlling the production of alternatively-spliced isoforms of type II procollagen (Col2a1) in vivo. During chondrogenesis, precursor chondrocytes predominantly produce isoforms containing alternatively-spliced exon 2 (type IIA and IID) while Col2a1 mRNA devoid of exon 2 (type IIB) is the major isoform produced by differentiated chondrocytes. We previously identified an additional Col2a1 isoform containing a truncated exon 2 and premature termination codo...

  13. Survivin isoforms and clinicopathological characteristics in colorectal adenocarcinomas using real-time qPCR

    Science.gov (United States)

    Pavlidou, Anastasia; Dalamaga, Maria; Kroupis, Christos; Konstantoudakis, George; Belimezi, Maria; Athanasas, George; Dimas, Kleanthi

    2011-01-01

    AIM: To investigate three isoforms of survivin in colorectal adenocarcinomas. METHODS: We used the LightCycler Technology (Roche), along with a common forward primer and reverse primers specific for the splice variants and two common hybridization probes labeled with fluorescein and LightCycler-Red fluorophore (LC-Red 640). Real time quantitative polymerase chain reaction (PCR) was performed on cDNAs from 52 tumor specimens from colorectal cancer patients and 10 unrelated normal colorectal tissues. In the patients group, carcinoembryonic antigen (CEA) and CA19-9 tumor markers were also measured immunochemically. RESULTS: Wild type survivin mRNA isoform was expressed in 48% of the 52 tumor samples, survivin-2b in 38% and survivin-ΔΕx3 in 29%, while no expression was found in normal tissues. The mRNA expression of wild type survivin presented a significant correlation with the expression of the ratio of survivin-2b, survivin-ΔΕx3, survivin-2b/wild type survivin and survivin-ΔΕx3/wild type survivin (P < 0.001). The mRNA expression of wild-survivin and survivin-ΔΕx3 was related with tumor size and invasion (P = 0.006 and P < 0.005, respectively). A significant difference was found between survivin-2b and morphologic cancer type. Also, the ratio of survivin-ΔEx3/wild-survivin was significantly associated with prognosis. No association was observed between the three isoforms and grade, metastasis, Dukes stage and gender. The three isoforms were not correlated with CEA and CA19-9. CONCLUSION: Survivin isoforms may play a role in cell apoptosis and their quantification could provide information about clinical management of patients suffering from colorectal cancer. PMID:21472129

  14. Survivin isoforms and clinicopathological characteristics in colorectal adenocarcinomas using real-time qPCR

    Institute of Scientific and Technical Information of China (English)

    Anastasia Pavlidou; Maria Dalamaga; Christos Kroupis; George Konstantoudakis; Maria Belimezi; George Athanasas; Kleanthi Dimas

    2011-01-01

    AIM: To investigate three isoforms of survivin in colorectal adenocarcinomas. METHODS: We used the LightCycler Technology (Roche), along with a common forward primer and reverse primers specific for the splice variants and two common hybridization probes labeled with fluorescein and LightCycler- Red fluorophore (LC-Red 640). Real time quantitative polymerase chain reaction (PCR) was performed on cDNAs from 52 tumor specimens from colorectal cancer patients and 10 unrelated normal colorectal tissues. In the patients group, carcinoembryonic antigen (CEA) and CA19-9 tumor markers were also measured immunochemically. RESULTS: Wild type survivin mRNA isoform was expressed in 48% of the 52 tumor samples, survivin-2b in 38% and survivin-ΔΕx3 in 29%, while no expression was found in normal tissues. The mRNA expression of wild type survivin presented a significant correlation with the expression of the ratio of survivin-2b, survivin-ΔΕx3, survivin-2b/wild type survivin and survivin-ΔΕx3/wild type survivin (P < 0.001). The mRNA expression of wildsurvivin and survivin-ΔΕx3 was related with tumor size and invasion (P = 0.006 and P < 0.005, respectively). A significant difference was found between survivin-2b and morphologic cancer type. Also, the ratio of survivin-ΔEx3/ wild-survivin was significantly associated with prognosis. No association was observed between the three isoforms and grade, metastasis, Dukes stage and gender. The three isoforms were not correlated with CEA and CA19-9. CONCLUSION: Survivin isoforms may play a role in cell apoptosis and their quantification could provide information about clinical management of patients suffering from colorectal cancer.

  15. Isoform-specific proteasomal degradation of Rbfox3 during chicken embryonic development

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kee K.; Adelstein, Robert S.; Kawamoto, Sachiyo, E-mail: kawamots@mail.nih.gov

    2014-08-08

    Highlights: • Protein stability of Rbfox3 splice isoforms is differentially regulated. • Rbfox3-d31, an Rbfox3 isoform lacking the RRM, is highly susceptible to degradation. • The protein stability of Rbfox3-d31 is regulated by the ubiquitin–proteasome pathway. • Rbfox3-d31 inhibits the nuclear localization of Rbfox2. • Rbfox3-d31 inhibits the splicing activity of Rbfox2. - Abstract: Rbfox3, a neuron-specific RNA-binding protein, plays an important role in neuronal differentiation during development. An isoform Rbfox3-d31, which excludes the 93-nucleotide cassette exon within the RNA recognition motif of chicken Rbfox3, has been previously identified. However, the cellular functions of Rbfox3-d31 remain largely unknown. Here we find that Rbfox3-d31 mRNA is highly expressed during the early developmental stages of the chicken embryo, while Rbfox3-d31 protein is barely detected during the same stage due to its rapid degradation mediated by the ubiquitin–proteasome pathway. Importantly, this degradation is specific to the Rbfox3-d31 isoform and it does not occur with full-length Rbfox3. Furthermore, suppression of Rbfox3-d31 protein degradation with the proteasome inhibitor MG132 attenuates the splicing activity of another Rbfox family member Rbfox2 by altering the subcellular localization of Rbfox2. These results suggest that Rbfox3-d31 functions as a repressor for the splicing activity of the Rbfox family and its protein level is regulated in an isoform-specific manner in vivo.

  16. Identification of alternatively spliced Dab1 and Fyn isoforms in pig

    Directory of Open Access Journals (Sweden)

    Yuan Jihong

    2011-02-01

    Full Text Available Abstract Background Disabled-1 (Dab1 is an adaptor protein that is essential for the intracellular transduction of Reelin signaling, which regulates the migration and differentiation of postmitotic neurons during brain development in vertebrates. Dab1 function depends on its tyrosine phosphorylation by Src family kinases, especially Fyn. Results We have isolated alternatively spliced forms of porcine Dab1 from brain (sDab1 and liver (sDab1-Li and Fyn from brain (sFyn-B and spleen (sFyn-T. Radiation hybrid mapping localized porcine Dab1 (sDab1 and Fyn (sFyn to chromosomes 6q31-35 and 1p13, respectively. Real-time quantitative RT-PCR (qRT-PCR demonstrated that different isoforms of Dab1 and Fyn have tissue-specific expression patterns, and sDab1 and sFyn-B display similar temporal expression characteristics in the developing porcine cerebral cortex and cerebellum. Both sDab1 isoforms function as nucleocytoplasmic shuttling proteins. It was further shown that sFyn phosphorylates sDab1 at tyrosyl residues (Tyr 185, 198/200 and 232, whereas sDab1-Li was phosphorylated at Tyr 185 and Tyr 197 (corresponding to Y232 in sDab1 in vitro. Conclusions Alternative splicing generates natural sDab1-Li that only carries Y185 and Y197 (corresponding to Y232 in sDab1 sites, which can be phosphorylated by Fyn in vitro. sDab1-Li is an isoform that is highly expressed in peripheral organs. Both isoforms are suggested to be nucleocytoplasmic shuttling proteins. Our results imply that the short splice form sDab1-Li might regulate cellular responses to different cell signals by acting as a dominant negative form against the full length sDab1 variant and that both isoforms might serve different signaling functions in different tissues.

  17. Multiple, but Concerted Cellular Activities of the Human Protein Hap46/BAG-1M and Isoforms

    Directory of Open Access Journals (Sweden)

    Ulrich Gehring

    2009-03-01

    Full Text Available The closely related human and murine proteins Hap46/BAG-1M and BAG-1, respectively, were discovered more than a decade ago by molecular cloning techniques. These and the larger isoform Hap50/BAG-1L, as well as shorter isoforms, have the ability to interact with a seemingly unlimited array of proteins of completely unrelated structures. This problem was partially resolved when it was realized that molecular chaperones of the hsp70 heat shock protein family are major primary association partners, binding being mediated by the carboxy terminal BAG-domain and the ATP-binding domain of hsp70 chaperones. The latter, in turn, can associate with an almost unlimited variety of proteins through their substrate-binding domains, so that ternary complexes may result. The protein folding activity of hsp70 chaperones is affected by interactions with Hap46/BAG-1M or isoforms. However, there also exist several proteins which bind to Hap46/BAG-1M and isoforms independent of hsp70 mediation. Moreover, Hap46/BAG-1M and Hap50/BAG-1L, but not the shorter isoforms, can bind to DNA in a sequence-independent manner by making use of positively charged regions close to their amino terminal ends. This is the molecular basis for their effects on transcription which are of major physiological relevance, as discussed here in terms of a model. The related proteins Hap50/BAG-1L and Hap46/BAG-1M may thus serve as molecular links between such diverse bioactivities as regulation of gene expression and protein quality control. These activities are coordinated and synergize in helping cells to cope with conditions of external stress. Moreover, they recently became markers for the aggressiveness of several cancer types.

  18. Isoform-specific proteasomal degradation of Rbfox3 during chicken embryonic development

    International Nuclear Information System (INIS)

    Highlights: • Protein stability of Rbfox3 splice isoforms is differentially regulated. • Rbfox3-d31, an Rbfox3 isoform lacking the RRM, is highly susceptible to degradation. • The protein stability of Rbfox3-d31 is regulated by the ubiquitin–proteasome pathway. • Rbfox3-d31 inhibits the nuclear localization of Rbfox2. • Rbfox3-d31 inhibits the splicing activity of Rbfox2. - Abstract: Rbfox3, a neuron-specific RNA-binding protein, plays an important role in neuronal differentiation during development. An isoform Rbfox3-d31, which excludes the 93-nucleotide cassette exon within the RNA recognition motif of chicken Rbfox3, has been previously identified. However, the cellular functions of Rbfox3-d31 remain largely unknown. Here we find that Rbfox3-d31 mRNA is highly expressed during the early developmental stages of the chicken embryo, while Rbfox3-d31 protein is barely detected during the same stage due to its rapid degradation mediated by the ubiquitin–proteasome pathway. Importantly, this degradation is specific to the Rbfox3-d31 isoform and it does not occur with full-length Rbfox3. Furthermore, suppression of Rbfox3-d31 protein degradation with the proteasome inhibitor MG132 attenuates the splicing activity of another Rbfox family member Rbfox2 by altering the subcellular localization of Rbfox2. These results suggest that Rbfox3-d31 functions as a repressor for the splicing activity of the Rbfox family and its protein level is regulated in an isoform-specific manner in vivo

  19. Fatal Hepatitis Mediated by TNFα Requires Caspase-8 and Involves the BH3-only Proteins Bid and Bim

    OpenAIRE

    Kaufmann, Thomas; Jost, Philipp J; Pellegrini, Marc; Puthalakath, Hamsa; Gugasyan, Raffi; Gerondakis, Steve; Cretney, Erika; Smyth, Mark J.; Silke, John; Hakem, Razq; Bouillet, Philippe; Mak, Tak W; Dixit, Vishva M.; Strasser, Andreas

    2009-01-01

    Apoptotic death of hepatocytes, a feature and contributing factor of many chronic and acute liver diseases, can be a consequence of over-activation of the immune system. Injection with lipopolysaccharide (LPS) plus the transcriptional inhibitor D(+)-galactosamine (GalN) or mitogenic T cell activation cause fatal hepatocyte apoptosis in mice. In both settings hepatocyte killing is mediated by TNFα/TNF-R signaling but the effector mechanisms remain unclear. Our analysis of gene-targeted mice sh...

  20. The Non-receptor Tyrosine Kinase Tec Controls Assembly and Activity of the Noncanonical Caspase-8 Inflammasome

    OpenAIRE

    Zwolanek, Florian; Riedelberger, Michael; Stolz, Valentina; Jenull, Sabrina; Istel, Fabian; Köprülü, Afitap Derya; Ellmeier, Wilfried; Kuchler, Karl

    2014-01-01

    Author Summary Inflammasomes represent multi-protein complexes and their activation during microbial infections is key in driving hyperinflammation through the maturation and release of IL-1β, as well as by directly inducing several pro-inflammatory cytokines during the host pathogen interaction. Thus, inflammasomes are involved in the induction of pathogen-induced sepsis in mice and men. However, the precise regulation and molecules involved in triggering the assembly and activation of infla...

  1. Crystallization and identification of the glycosylated moieties of two isoforms of the main allergen Hev b 2 and preliminary X-ray analysis of two polymorphs of isoform II

    International Nuclear Information System (INIS)

    Crystallization of important glycoenzymes involved in IgE-mediated latex allergy. Latex from Hevea brasiliensis contains several allergenic proteins that are involved in type I allergy. One of them is Hev b 2, which is a β-1,3-glucanase enzyme that exists in different isoforms with variable glycosylation content. Two glucanase isoforms were isolated from trees of the GV-42 clone by gel filtration, affinity and ion-exchange chromatography. Isoform I had a carbohydrate content of about 20%, with N-linked N-acetyl-glucosamine, N-acetyl-galactosamine, fucose and galactose residues as the main sugars, while isoform II showed 6% carbohydrate content constisting of N-acetyl-glucosamine, fucose, mannose and xylose. Both isoforms were crystallized by the hanging-drop vapour-diffusion method. Isoform I crystals were grown using 0.2 M trisodium citrate dihydrate, 0.1 M Na HEPES pH 7.5 and 20%(v/v) 2-propanol, but these crystals were not appropriate for data collection. Isoform II crystals were obtained under two conditions and X-ray diffraction data were collected from both. In the first condition (0.2 M trisodium citrate, 0.1 M sodium cacodylate pH 6.5, 30% 2-propanol), crystals belonging to the tetragonal space group P41 with unit-cell parameters a = b = 150.17, c = 77.41 Å were obtained. In the second condition [0.2 M ammonium acetate, 0.1 M trisodium citrate dihydrate pH 5.6, 30%(w/v) polyethylene glycol 4000] the isoform II crystals belonged to the monoclinic space group P21, with unit-cell parameters a = 85.08, b = 89.67, c = 101.80 Å, β = 113.6°. Preliminary analysis suggests that there are four molecules of isoform II in both asymmetric units

  2. Crystallization and identification of the glycosylated moieties of two isoforms of the main allergen Hev b 2 and preliminary X-ray analysis of two polymorphs of isoform II

    Energy Technology Data Exchange (ETDEWEB)

    Fuentes-Silva, D. [Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior s/n, Cuidad Universitaria, Coyoacán, México, DF 04510 (Mexico); Mendoza-Hernández, G. [Facultad de Medicina, Universidad Nacional Autónoma de México, Circuito Exterior s/n, Cuidad Universitaria, Coyoacán, México, DF 04510 (Mexico); Stojanoff, V. [Brookhaven National Laboratory, National Synchrotron Light Source, Upton, NY (United States); Palomares, L. A. [Instituto de Biotecnología, Universidad Nacional Autónoma de México, Circuito Exterior s/n, Cuidad Universitaria, Coyoacán, México, DF 04510 (Mexico); Zenteno, E. [Facultad de Medicina, Universidad Nacional Autónoma de México, Circuito Exterior s/n, Cuidad Universitaria, Coyoacán, México, DF 04510 (Mexico); Torres-Larios, A. [Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Circuito Exterior s/n, Cuidad Universitaria, Coyoacán, México, DF 04510 (Mexico); Rodríguez-Romero, A., E-mail: adela@servidor.unam.mx [Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior s/n, Cuidad Universitaria, Coyoacán, México, DF 04510 (Mexico)

    2007-09-01

    Crystallization of important glycoenzymes involved in IgE-mediated latex allergy. Latex from Hevea brasiliensis contains several allergenic proteins that are involved in type I allergy. One of them is Hev b 2, which is a β-1,3-glucanase enzyme that exists in different isoforms with variable glycosylation content. Two glucanase isoforms were isolated from trees of the GV-42 clone by gel filtration, affinity and ion-exchange chromatography. Isoform I had a carbohydrate content of about 20%, with N-linked N-acetyl-glucosamine, N-acetyl-galactosamine, fucose and galactose residues as the main sugars, while isoform II showed 6% carbohydrate content constisting of N-acetyl-glucosamine, fucose, mannose and xylose. Both isoforms were crystallized by the hanging-drop vapour-diffusion method. Isoform I crystals were grown using 0.2 M trisodium citrate dihydrate, 0.1 M Na HEPES pH 7.5 and 20%(v/v) 2-propanol, but these crystals were not appropriate for data collection. Isoform II crystals were obtained under two conditions and X-ray diffraction data were collected from both. In the first condition (0.2 M trisodium citrate, 0.1 M sodium cacodylate pH 6.5, 30% 2-propanol), crystals belonging to the tetragonal space group P4{sub 1} with unit-cell parameters a = b = 150.17, c = 77.41 Å were obtained. In the second condition [0.2 M ammonium acetate, 0.1 M trisodium citrate dihydrate pH 5.6, 30%(w/v) polyethylene glycol 4000] the isoform II crystals belonged to the monoclinic space group P2{sub 1}, with unit-cell parameters a = 85.08, b = 89.67, c = 101.80 Å, β = 113.6°. Preliminary analysis suggests that there are four molecules of isoform II in both asymmetric units.

  3. Crystallization and Identification of the Glycosylated Moieties of Two Isoforms of the Main Allergen Hev b 2 and Preliminary X-ray Analysis of Two Polymorphs of Isoform ll

    Energy Technology Data Exchange (ETDEWEB)

    Fuentes-Silva,D.; Mendoza-Hernandez, G.; Stojanoff, V.; Palomares, L.; Zenteno, E.; Torres-Larios, A.; Rodriguez-Romero, A.

    2007-01-01

    Latex from Hevea brasiliensis contains several allergenic proteins that are involved in type I allergy. One of them is Hev b 2, which is a {beta}-1,3-glucanase enzyme that exists in different isoforms with variable glycosylation content. Two glucanase isoforms were isolated from trees of the GV-42 clone by gel filtration, affinity and ion-exchange chromatography. Isoform I had a carbohydrate content of about 20%, with N-linked N-acetyl-glucosamine, N-acetyl-galactosamine, fucose and galactose residues as the main sugars, while isoform II showed 6% carbohydrate content consisting of N-acetyl-glucosamine, fucose, mannose and xylose. Both isoforms were crystallized by the hanging-drop vapor-diffusion method. Isoform I crystals were grown using 0.2 M trisodium citrate dihydrate, 0.1 M Na HEPES pH 7.5 and 20%(v/v) 2-propanol, but these crystals were not appropriate for data collection. Isoform II crystals were obtained under two conditions and X-ray diffraction data were collected from both. In the first condition (0.2 M trisodium citrate, 0.1 M sodium cacodylate pH 6.5, 30% 2-propanol), crystals belonging to the tetragonal space group P4{sub 1} with unit-cell parameters a = b = 150.17, c = 77.41 {angstrom} were obtained. In the second condition [0.2 M ammonium acetate, 0.1 M trisodium citrate dihydrate pH 5.6, 30%(w/v) polyethylene glycol 4000] the isoform II crystals belonged to the monoclinic space group P2{sub 1}, with unit-cell parameters a = 85.08, b = 89.67, c = 101.80 {angstrom}, {beta}= 113.6{sup o}. Preliminary analysis suggests that there are four molecules of isoform II in both asymmetric units.

  4. Cloning of a soluble isoform of the SgIGSF adhesion molecule that binds the extracellular domain of the membrane-bound isoform.

    OpenAIRE

    Koma, Yu-ichiro; Ito, Akihiko; Wakayama, Tomohiko; Watabe, Kenji; OKADA, Morihito; Tsubota, Noriaki; Iseki, Shoichi; Kitamura, Yukihiko

    2004-01-01

    SgIGSF (spermatogenic immunoglobulin superfamily) is a recently identified intercellular adhesion molecule of the immunoglobulin superfamily. In a mast-cell cDNA library, we found a clone that resulted from the retention of intron 7 within the mature SgIGSF message. This clone was predicted to encode a soluble isoform of SgIGSF (sSgIGSF) with 336 amino-acid residues because its open reading frame ended just before the transmembrane domain. We constructed a plasmid expressing sSgIGSF fused to ...

  5. Two alternatively spliced isoforms of the Arabidopsis SR45 protein have distinct roles during normal plant development.

    Science.gov (United States)

    Zhang, Xiao-Ning; Mount, Stephen M

    2009-07-01

    The serine-arginine-rich (SR) proteins constitute a conserved family of pre-mRNA splicing factors. In Arabidopsis (Arabidopsis thaliana), they are encoded by 19 genes, most of which are themselves alternatively spliced. In the case of SR45, the use of alternative 3' splice sites 21 nucleotides apart generates two alternatively spliced isoforms. Isoform 1 (SR45.1) has an insertion relative to isoform 2 (SR45.2) that replaces a single arginine with eight amino acids (TSPQRKTG). The biological implications of SR45 alternative splicing have been unclear. A previously described loss-of-function mutant affecting both isoforms, sr45-1, shows several developmental defects, including defects in petal development and root growth. We found that the SR45 promoter is highly active in regions with actively growing and dividing cells. We also tested the ability of each SR45 isoform to complement the sr45-1 mutant by overexpression of isoform-specific green fluorescent protein (GFP) fusion proteins. As expected, transgenic plants overexpressing either isoform displayed both nuclear speckles and GFP fluorescence throughout the nucleoplasm. We found that SR45.1-GFP complements the flower petal phenotype, but not the root growth phenotype. Conversely, SR45.2-GFP complements root growth but not floral morphology. Mutation of a predicted phosphorylation site within the alternatively spliced segment, SR45.1-S219A-GFP, does not affect complementation. However, a double mutation affecting both serine-219 and the adjacent threonine-218 (SR45.1-T218A + S219A-GFP) behaves like isoform 2, complementing the root but not the floral phenotype. In conclusion, our study provides evidence that the two alternatively spliced isoforms of SR45 have distinct biological functions. PMID:19403727

  6. Identification of novel chicken estrogen receptor-alpha messenger ribonucleic acid isoforms generated by alternative splicing and promoter usage.

    Science.gov (United States)

    Griffin, C; Flouriot, G; Sonntag-Buck, V; Nestor, P; Gannon, F

    1998-11-01

    Using the rapid amplification of complementary DNA ends (RACE) methodology we have identified three new chicken estrogen receptor-alpha (cER alpha) messenger RNA (mRNA) variants in addition to the previously described form (isoform A). Whereas one of the new variants (isoform B) presents a 5'-extremity contiguous to the 5'-end of isoform A, the two other forms (isoforms C and D) are generated by alternative splicing of upstream exons (C and D) to a common site situated 70 nucleotides upstream of the translation start site in the previously assigned exon 1 (A). The 3'-end of exon 1C has been located at position -1334 upstream of the transcription start site of the A isoform (+1). Whereas the genomic location of exon 1D is unknown, 700 bp 5' to this exon were isolated by genomic walking, and their sequence was determined. The transcription start sites of the cER alpha mRNA isoforms were defined. In transfection experiments, the regions immediately upstream of the A-D cER alpha mRNA isoforms were shown to possess cell-specific promoter activities. Three of these promoters were down-regulated in the presence of estradiol and ER alpha protein. It is concluded, therefore, that the expression of the four different cER alpha mRNA isoforms is under the control of four different promoters. Finally, RT-PCR, S1 nuclease mapping, and primer extension analysis of these different cER alpha mRNA isoforms revealed a differential pattern of expression of the cER alpha gene in chicken tissues. Together, the results suggest that alternative 5'-splicing and promoter usage may be mechanisms used to modulate the levels of expression of the chicken ER alpha gene in a tissue-specific and/or developmental stage-specific manner. PMID:9794473

  7. Conditional expression of CD44 isoforms in lymphoma cells: influence on hyaluronate binding and tumor growth

    International Nuclear Information System (INIS)

    CD44 describes a family of surface proteins consisting of many isoforms due to alternative splice of ten 'variant' exons. Members of this family are involved in various processes including hematopoiesis, lymphocyte activation and homing, limb development, wound healing and tumor progression. Clinically, CD44 has been shown to be a prognostic factor for several human cancers. To answer the question which isoform might be relevant for tumor progression and to gain an insight into the mechanism of its function, I established transfectants of the LB lymphoma cell line in which the expression of four CD44 isoforms, namely CD44v3-10, CD44v4-10, CD44v8-10 and CD44s, was controlled by the Tet-off promoter. In the presence of Doxycycline, the expression was repressed. Removal of Doxycycline switched on expression and the maximal CD44 amount was obtained within two days. The transfectants were characterized regarding their ability to bind to the extracellular matrix component hyaluronate (HA). Overexpression of all four CD44 isoforms conferred the ability to bind HA on LB cells. Other glycosaminoglycans (GAGs) were bound in an isotype-specific fashion. CD44v3-10, CD44v4-10 and CD44v8-10 showed high binding affinity to chondroitin A, B and C, and low affinity to heparin, heparan sulfate and keratan sulfate. CD44s could not bind to these GAGs. Among these three variants, the binding ability of CD44v3-10 was the strongest. CD44 clustering seemed to play a crucial role for HA binding. Both CD44s and CD44v8-10 formed reduction-sensitive complexes in LB cells. The complexes are homooligomers or heterooligomers composed of different isoforms. Cys286 in CD44 transmember domain was not responsible for the formation of reduction-sensitive oligomer or for the enhanced HA binding in LB cell line. Using a conditional dimerization system the requirement of CD44 oligomerization for HA binding was directly demonstrated. The induction of oligomerization increased HA binding. Finally, I

  8. Isoform-specific potentiation of stem and progenitor cell engraftment by AML1/RUNX1.

    Directory of Open Access Journals (Sweden)

    Shinobu Tsuzuki

    2007-05-01

    Full Text Available BACKGROUND: AML1/RUNX1 is the most frequently mutated gene in leukaemia and is central to the normal biology of hematopoietic stem and progenitor cells. However, the role of different AML1 isoforms within these primitive compartments is unclear. Here we investigate whether altering relative expression of AML1 isoforms impacts the balance between cell self-renewal and differentiation in vitro and in vivo. METHODS AND FINDINGS: The human AML1a isoform encodes a truncated molecule with DNA-binding but no transactivation capacity. We used a retrovirus-based approach to transduce AML1a into primitive haematopoietic cells isolated from the mouse. We observed that enforced AML1a expression increased the competitive engraftment potential of murine long-term reconstituting stem cells with the proportion of AML1a-expressing cells increasing over time in both primary and secondary recipients. Furthermore, AML1a expression dramatically increased primitive and committed progenitor activity in engrafted animals as assessed by long-term culture, cobblestone formation, and colony assays. In contrast, expression of the full-length isoform AML1b abrogated engraftment potential. In vitro, AML1b promoted differentiation while AML1a promoted proliferation of progenitors capable of short-term lymphomyeloid engraftment. Consistent with these findings, the relative abundance of AML1a was highest in the primitive stem/progenitor compartment of human cord blood, and forced expression of AML1a in these cells enhanced maintenance of primitive potential both in vitro and in vivo. CONCLUSIONS: These data demonstrate that the "a" isoform of AML1 has the capacity to potentiate stem and progenitor cell engraftment, both of which are required for successful clinical transplantation. This activity is consistent with its expression pattern in both normal and leukaemic cells. Manipulating the balance of AML1 isoform expression may offer novel therapeutic strategies, exploitable in

  9. Conditional expression of CD44 isoforms in lymphoma cells: influence on hyaluronate binding and tumor growth

    Energy Technology Data Exchange (ETDEWEB)

    Fu, J.

    2002-03-01

    CD44 describes a family of surface proteins consisting of many isoforms due to alternative splice of ten 'variant' exons. Members of this family are involved in various processes including hematopoiesis, lymphocyte activation and homing, limb development, wound healing and tumor progression. Clinically, CD44 has been shown to be a prognostic factor for several human cancers. To answer the question which isoform might be relevant for tumor progression and to gain an insight into the mechanism of its function, I established transfectants of the LB lymphoma cell line in which the expression of four CD44 isoforms, namely CD44v3-10, CD44v4-10, CD44v8-10 and CD44s, was controlled by the Tet-off promoter. In the presence of Doxycycline, the expression was repressed. Removal of Doxycycline switched on expression and the maximal CD44 amount was obtained within two days. The transfectants were characterized regarding their ability to bind to the extracellular matrix component hyaluronate (HA). Overexpression of all four CD44 isoforms conferred the ability to bind HA on LB cells. Other glycosaminoglycans (GAGs) were bound in an isotype-specific fashion. CD44v3-10, CD44v4-10 and CD44v8-10 showed high binding affinity to chondroitin A, B and C, and low affinity to heparin, heparan sulfate and keratan sulfate. CD44s could not bind to these GAGs. Among these three variants, the binding ability of CD44v3-10 was the strongest. CD44 clustering seemed to play a crucial role for HA binding. Both CD44s and CD44v8-10 formed reduction-sensitive complexes in LB cells. The complexes are homooligomers or heterooligomers composed of different isoforms. Cys286 in CD44 transmember domain was not responsible for the formation of reduction-sensitive oligomer or for the enhanced HA binding in LB cell line. Using a conditional dimerization system the requirement of CD44 oligomerization for HA binding was directly demonstrated. The induction of oligomerization increased HA binding

  10. Influenza A Viruses Control Expression of Proviral Human p53 Isoforms p53β and Δ133p53α

    OpenAIRE

    Terrier, Olivier; Marcel, Virginie; Cartet, Gaëlle; Lane, David P; Lina, Bruno; Rosa-Calatrava, Manuel; Bourdon, Jean-Christophe

    2012-01-01

    Previous studies have described the role of p53 isoforms, including p53β and Δ133p53α, in the modulation of the activity of full-length p53, which regulates cell fate. In the context of influenza virus infection, an interplay between influenza viruses and p53 has been described, with p53 being involved in the antiviral response. However, the role of physiological p53 isoforms has never been explored in this context. Here, we demonstrate that p53 isoforms play a role in influenza A virus infec...

  11. Brain region-specific expression of MeCP2 isoforms correlates with DNA methylation within Mecp2 regulatory elements.

    Directory of Open Access Journals (Sweden)

    Carl O Olson

    Full Text Available MeCP2 is a critical epigenetic regulator in brain and its abnormal expression or compromised function leads to a spectrum of neurological disorders including Rett Syndrome and autism. Altered expression of the two MeCP2 isoforms, MeCP2E1 and MeCP2E2 has been implicated in neurological complications. However, expression, regulation and functions of the two isoforms are largely uncharacterized. Previously, we showed the role of MeCP2E1 in neuronal maturation and reported MeCP2E1 as the major protein isoform in the adult mouse brain, embryonic neurons and astrocytes. Recently, we showed that DNA methylation at the regulatory elements (REs within the Mecp2 promoter and intron 1 impact the expression of Mecp2 isoforms in differentiating neural stem cells. This current study is aimed for a comparative analysis of temporal, regional and cell type-specific expression of MeCP2 isoforms in the developing and adult mouse brain. MeCP2E2 displayed a later expression onset than MeCP2E1 during mouse brain development. In the adult female and male brain hippocampus, both MeCP2 isoforms were detected in neurons, astrocytes and oligodendrocytes. Furthermore, MeCP2E1 expression was relatively uniform in different brain regions (olfactory bulb, striatum, cortex, hippocampus, thalamus, brainstem and cerebellum, whereas MeCP2E2 showed differential enrichment in these brain regions. Both MeCP2 isoforms showed relatively similar distribution in these brain regions, except for cerebellum. Lastly, a preferential correlation was observed between DNA methylation at specific CpG dinucleotides within the REs and Mecp2 isoform-specific expression in these brain regions. Taken together, we show that MeCP2 isoforms display differential expression patterns during brain development and in adult mouse brain regions. DNA methylation patterns at the Mecp2 REs may impact this differential expression of Mecp2/MeCP2 isoforms in brain regions. Our results significantly contribute

  12. Identification of T-Cell Factor-4 isoforms that contribute to the malignant phenotype of hepatocellular carcinoma cells

    OpenAIRE

    Tsedensodnom, Orkhontuya; Koga, Hironori; Rosenberg, Stephen A.; Nambotin, Sarah B.; Carroll, John J.; Wands, Jack R.; Kim, Miran

    2011-01-01

    The Wnt/β-catenin signaling pathway is frequently activated in hepatocellular carcinoma (HCC). Downstream signaling events involving the Wnt/β-catenin cascade occur through T-cell factor (TCF) proteins. The human TCF-4 gene is composed of 17 exons with multiple alternative splicing sites. However, the role of different TCF-4 isoforms in the pathogenesis of HCC is unknown. The purpose of this study was to identify and characterize TCF-4 isoforms in HCC. We identified 14 novel TCF-4 isoforms fr...

  13. The expression of ELK transcription factors in adult DRG: novel isoforms, antisense transcripts and upregulation by nerve damage

    OpenAIRE

    Kerr, Niall; Pintzas, Alexander; Holmes, Fiona; Hobson, Sally-Ann; Pope, Robert; Wallace, Mark; Wasylyk, Christine; Wasylyk, Bohdan; Wynick, David

    2010-01-01

    ELK transcription factors are expressed in brain, but it is unknown whether they are expressed in the peripheral nervous system. We show by RT-PCR that the previously described Elk1, Elk3/Elk3b/Elk3c and Elk4 mRNAs are expressed in adult dorsal root ganglia (DRG), together with the novel alternatively spliced isoforms Elk1b, Elk3d and Elk4c/Elk4d/Elk4e. These isoforms are also expressed in brain, heart, kidney and testis. In contrast to Elk3 protein, the novel Elk3d isoform is cytoplasmic, fa...

  14. Deep Proteomics of Mouse Skeletal Muscle Enables Quantitation of Protein Isoforms, Metabolic Pathways, and Transcription Factors*

    Science.gov (United States)

    Deshmukh, Atul S.; Murgia, Marta; Nagaraj, Nagarjuna; Treebak, Jonas T.; Cox, Jürgen; Mann, Matthias

    2015-01-01

    Skeletal muscle constitutes 40% of individual body mass and plays vital roles in locomotion and whole-body metabolism. Proteomics of skeletal muscle is challenging because of highly abundant contractile proteins that interfere with detection of regulatory proteins. Using a state-of-the art MS workflow and a strategy to map identifications from the C2C12 cell line model to tissues, we identified a total of 10,218 proteins, including skeletal muscle specific transcription factors like myod1 and myogenin and circadian clock proteins. We obtain absolute abundances for proteins expressed in a muscle cell line and skeletal muscle, which should serve as a valuable resource. Quantitation of protein isoforms of glucose uptake signaling pathways and in glucose and lipid metabolic pathways provides a detailed metabolic map of the cell line compared with tissue. This revealed unexpectedly complex regulation of AMP-activated protein kinase and insulin signaling in muscle tissue at the level of enzyme isoforms. PMID:25616865

  15. Design and Synthesis of Simplified Largazole Analogues as Isoform-Selective Human Lysine Deacetylase Inhibitors.

    Science.gov (United States)

    Reddy, Damodara N; Ballante, Flavio; Chuang, Timothy; Pirolli, Adele; Marrocco, Biagina; Marshall, Garland R

    2016-02-25

    Selective inhibition of KDAC isoforms while maintaining potency remains a challenge. Using the largazole macrocyclic depsipeptide structure as a starting point for developing new KDACIs with increased selectivity, a combination of four different simplified largazole analogue (SLA) scaffolds with diverse zinc-binding groups (for a total of 60 compounds) were designed, synthesized, and evaluated against class I KDACs 1, 3, and 8, and class II KDAC6. Experimental evidence as well as molecular docking poses converged to establish the cyclic tetrapeptides (CTPs) as the primary determinant of both potency and selectivity by influencing the correct alignment of the zinc-binding group in the KDAC active site, providing a further basis for developing new KDACIs of higher isoform selectivity and potency. PMID:26681404

  16. Differentiation of Human Parthenogenetic Pluripotent Stem Cells Reveals Multiple Tissue- and Isoform-Specific Imprinted Transcripts

    Directory of Open Access Journals (Sweden)

    Yonatan Stelzer

    2015-04-01

    Full Text Available Parental imprinting results in monoallelic parent-of-origin-dependent gene expression. However, many imprinted genes identified by differential methylation do not exhibit complete monoallelic expression. Previous studies demonstrated complex tissue-dependent expression patterns for some imprinted genes. Still, the complete magnitude of this phenomenon remains largely unknown. By differentiating human parthenogenetic induced pluripotent stem cells into different cell types and combining DNA methylation with a 5′ RNA sequencing methodology, we were able to identify tissue- and isoform-dependent imprinted genes in a genome-wide manner. We demonstrate that nearly half of all imprinted genes express both biallelic and monoallelic isoforms that are controlled by tissue-specific alternative promoters. This study provides a global analysis of tissue-specific imprinting in humans and suggests that alternative promoters are central in the regulation of imprinted genes.

  17. Algal Toxin Azaspiracid-1 Induces Early Neuronal Differentiation and Alters Peripherin Isoform Stoichiometry

    Directory of Open Access Journals (Sweden)

    Linda V. Hjørnevik

    2015-12-01

    Full Text Available Azaspiracid-1 is an algal toxin that accumulates in edible mussels, and ingestion may result in human illness as manifested by vomiting and diarrhoea. When injected into mice, it causes neurotoxicological symptoms and death. Although it is well known that azaspiracid-1 is toxic to most cells and cell lines, little is known about its biological target(s. A rat PC12 cell line, commonly used as a model for the peripheral nervous system, was used to study the neurotoxicological effects of azaspiracid-1. Azaspiracid-1 induced differentiation-related morphological changes followed by a latter cell death. The differentiated phenotype showed peripherin-labelled neurite-like processes simultaneously as a specific isoform of peripherin was down-regulated. The precise mechanism behind this down-regulation remains uncertain. However, this study provides new insights into the neurological effects of azaspiracid-1 and into the biological significance of specific isoforms of peripherin.

  18. Characterisation of human fibroblasts as keratinocyte feeder layer using p63 isoforms status.

    Science.gov (United States)

    Auxenfans, Céline; Thépot, Amélie; Justin, Virginie; Hautefeuille, Agnès; Shahabeddin, Lili; Damour, Odile; Hainaut, Pierre

    2009-01-01

    Large-scale culture of primary keratinocytes allows the production of large epidermal sheet surfaces for the treatment of extensive skin burns. This method is dependent upon the capacity to establish cultures of proliferating keratinocytes in conditions compatible with their clonal expansion while maintaining their capacity to differentiate into the typical squamous pattern of human epidermis. Feeder layers are critical in this process because the fibroblasts that compose this layer serve as a source of adhesion, growth and differentiation factors. In this report, we have characterise the expression patterns of p63 isoforms in primary keratinocytes cultured on two different feeder layer systems, murine 3T3 and human fibroblasts. We show that with the latter, keratinocytes express a higher ratio of Delta N to TAp63 isoform, in relation with higher clonogenic potential. These results indicate that human fibroblasts represent an adequate feeder layer system to support the culture of primary human keratinocytes. PMID:20042803

  19. Detection of Diverse and High Molecular Weight Nesprin-1 and Nesprin-2 Isoforms Using Western Blotting.

    Science.gov (United States)

    Carthew, James; Karakesisoglou, Iakowos

    2016-01-01

    Heavily utilized in cell and molecular biology, western blotting is considered a crucial technique for the detection and quantification of proteins within complex mixtures. In particular, the detection of members of the nesprin (nuclear envelope spectrin repeat protein) family has proven difficult to analyze due to their substantial isoform diversity, molecular weight variation, and the sheer size of both nesprin-1 and nesprin-2 giant protein variants (>800 kDa). Nesprin isoforms contain distinct domain signatures, perform differential cytoskeletal associations, occupy different subcellular compartments, and vary in their tissue expression profiles. This structural and functional variance highlights the need to distinguish between the full range of proteins within the nesprin protein family, allowing for greater understanding of their specific roles in cell biology and disease. Herein, we describe a western blotting protocol modified for the detection of low to high molecular weight (50-1000 kDa) nesprin proteins. PMID:27147045

  20. Isoform-specific anti-MeCP2 antibodies confirm that expression of the e1 isoform strongly predominates in the brain [v1; ref status: indexed, http://f1000r.es/1mg

    Directory of Open Access Journals (Sweden)

    Lara Kaddoum

    2013-10-01

    Full Text Available Rett syndrome is a neurological disorder caused by mutations in the MECP2 gene.  MeCP2 transcripts are alternatively spliced to generate two protein isoforms (MeCP2_e1 and MeCP2_e2 that differ at their N-termini. Whilst mRNAs for both forms are expressed ubiquitously, the one for MeCP2_e1 is more abundant than for MeCP2_e2 in the central nervous system. In transfected cells, both protein isoforms are nuclear and colocalize with densely methylated heterochromatic foci. With a view to understanding the physiological contribution of each isoform, and their respective roles in the pathogenesis of Rett syndrome, we set out to generate isoform-specific anti-MeCP2 antibodies. To this end, we immunized rabbits against the peptides corresponding to the short amino-terminal portions that are different between the two isoforms. The polyclonal antibodies thus obtained specifically detected their respective isoforms of MeCP2 in Neuro2a (N2A cells transfected to express either form. Both antisera showed comparable sensitivities when used for Western blot or immunofluorescence, and were highly specific for their respective isoform. When those antibodies were used on mouse tissues, specific signals were easily detected for Mecp2_e1, whilst Mecp2_e2 was very difficult to detect by Western blot, and even more so by immunofluorescence. Our results thus suggest that brain cells express low amounts of the Mecp2-e2 isoform. Our findings are compatible with recent reports showing that MeCP2_e2 is dispensable for healthy brain function, and that it may be involved in the regulation of neuronal apoptosis and embryonic development.

  1. Prokaryotic expression and characterization of a pea actin isoform (PEAcl) fused to GFP

    Institute of Scientific and Technical Information of China (English)

    ZHANG Shaobin; REN Dongtao; XU Xiaojing; LIU Guoqin

    2004-01-01

    Actins widely exist in eukaryotic cells and play important roles in many living activities. As there are many kinds of actin isoforms in plant cells, it is difficult to purify each actin isoform in sufficient quantities for analyzing its physicochemical properties. In the present study, a pea(Pisum Sativum L.) actin isoform (PEAc1) fused to His-tag at its amino terminus and GFP (green fluorescent protein) at its Carboxyl terminus were expressed in E. Coli in inclusion bodies. The fusion protein (PEAc1-GFP) was highly purified with the yield of above 2 mg/L culture by dissolving inclusions in 8 mol/L urea, renaturing by dialysis in a gradient of urea, and affinity binding to Ni-resin. The purified mono meric PEAc1-GFP could efficiently bind on Dnase Ⅰ and inhibit the latter's enzyme activity. PEAc1-GFP could polymerize into green fluorescent filamentous structures (F-PEAc1-GFP), which could be labeled by TRITC-phalloidin, a specific agent for observing microfilaments. The PEAc1-GFP polymerization curve was identical with that of chicken skeletal muscle actin. The critical concentration for PEAc1-GFP to polymerize into filaments is 0.24 μmol/L. The F-PEAc1-GFP could stimulate myosin Mg-ATPase activity in a protein concentration dependant manner (about 4 folds at1 mg/mL F-PEAc1-GFP). The results above show that the PEAcl fused to GFP retained the assembly characteristic of actin, indicating that gene fusion, prokaryotic expression,denaturation and renaturation, and affinity chromatography is a useful strategy for obtaining plant actin isoform proteins in a large amount.

  2. Muscle-Type Specific Autophosphorylation of CaMKII Isoforms after Paced Contractions

    Directory of Open Access Journals (Sweden)

    Wouter Eilers

    2014-01-01

    Full Text Available We explored to what extent isoforms of the regulator of excitation-contraction and excitation-transcription coupling, calcium/calmodulin protein kinase II (CaMKII contribute to the specificity of myocellular calcium sensing between muscle types and whether concentration transients in its autophosphorylation can be simulated. CaMKII autophosphorylation at Thr287 was assessed in three muscle compartments of the rat after slow or fast motor unit-type stimulation and was compared against a computational model (CaMuZclE coupling myocellular calcium dynamics with CaMKII Thr287 phosphorylation. Qualitative differences existed between fast- (gastrocnemius medialis and slow-type muscle (soleus for the expression pattern of CaMKII isoforms. Phospho-Thr287 content of δA CaMKII, associated with nuclear functions, demonstrated a transient and compartment-specific increase after excitation, which contrasted to the delayed autophosphorylation of the sarcoplasmic reticulum-associated βM CaMKII. In soleus muscle, excitation-induced δA CaMKII autophosphorylation demonstrated frequency dependence (P = 0.02. In the glycolytic compartment of gastrocnemius medialis, CaMKII autophosphorylation after excitation was blunted. In silico assessment emphasized the importance of mitochondrial calcium buffer capacity for excitation-induced CaMKII autophosphorylation but did not predict its isoform specificity. The findings expose that CaMKII autophosphorylation with paced contractions is regulated in an isoform and muscle type-specific fashion and highlight properties emerging for phenotype-specific regulation of CaMKII.

  3. Two farnesoid X receptor alpha isoforms in Japanese medaka (Oryzias latipes) are differentially activated in vitro

    International Nuclear Information System (INIS)

    The nuclear receptor farnesoid X receptor alpha (FXRα, NR1H4) is activated by bile acids in multiple species including mouse, rat, and human and in this study we have identified two isoforms of Fxrα in Japanese medaka (Oryzias latipes), a small freshwater teleost. Both isoforms share a high amino acid sequence identity to mammalian FXRα (∼70% in the ligand-binding domain). Fxrα1 and Fxrα2 differ within the AF1 domain due to alternative splicing at the fourth intron-exon boundary. This process results in Fxrα1 having an extended N-terminus compared to Fxrα2. A Gal4DBD-FxrαLBD fusion construct was activated by chenodeoxycholic, cholic, deoxycholic and lithocholic acids, and the synthetic agonist GW4064 in transient transactivation assays. Activation of the Gal4DBD-FxrαLBD fusion construct was enhanced by addition of PGC-1α, as demonstrated through titration assays. Surprisingly, when the full-length versions of the two Fxrα isoforms were compared in transient transfection assays, Fxrα2 was activated by C24 bile acids and GW4064, while Fxrα1 was not significantly activated by any of the compounds tested. Since the only significant difference between the full-length constructs was sequence in the AF1 domain, these experiments highlight a key functional region in the Fxrα AF1 domain. Furthermore, mammalian two-hybrid studies demonstrated the ability of Fxrα2, but not Fxrα1, to interact with PGC-1α and SRC-1, and supported our results from the transient transfection reporter gene activation assays. These data demonstrate that both mammalian and teleost FXR (Fxrα2 isoform) are activated by primary and secondary bile acids.

  4. Two farnesoid X receptor alpha isoforms in Japanese medaka (Oryzias latipes) are differentially activated in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Howarth, Deanna L. [Integrated Toxicology and Environmental Health Program and Nicholas School of the Environment and Earth Sciences, Duke University, Durham, NC 27708 (United States); Hagey, Lee R. [Department of Medicine, University of California at San Diego, La Jolla, CA 92093 (United States); Law, Sheran H.W. [Department of Environmental and Molecular Toxicology, North Carolina State University, Raleigh, NC 27695 (United States); Ai, Ni [Department of Pharmacology, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, Piscataway, NJ 08854 (United States); Krasowski, Matthew D. [Department of Pathology, University of Iowa Hospitals and Clinics, Iowa City, IA (United States); Ekins, Sean [Department of Pharmacology, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, Piscataway, NJ 08854 (United States); Collaboration in Chemistry, Jenkintown, PA 19046 (United States); Department of Pharmaceutical Sciences, University of Maryland, Baltimore, MD 21201 (United States); Moore, John T. [GlaxoSmithKline Discovery Research, Research Triangle Park, NC 27709 (United States); Kollitz, Erin M. [Department of Environmental and Molecular Toxicology, North Carolina State University, Raleigh, NC 27695 (United States); Hinton, David E. [Integrated Toxicology and Environmental Health Program and Nicholas School of the Environment and Earth Sciences, Duke University, Durham, NC 27708 (United States); Kullman, Seth W., E-mail: swkullma@ncsu.edu [Department of Environmental and Molecular Toxicology, North Carolina State University, Raleigh, NC 27695 (United States)

    2010-07-01

    The nuclear receptor farnesoid X receptor alpha (FXR{alpha}, NR1H4) is activated by bile acids in multiple species including mouse, rat, and human and in this study we have identified two isoforms of Fxr{alpha} in Japanese medaka (Oryzias latipes), a small freshwater teleost. Both isoforms share a high amino acid sequence identity to mammalian FXR{alpha} ({approx}70% in the ligand-binding domain). Fxr{alpha}1 and Fxr{alpha}2 differ within the AF1 domain due to alternative splicing at the fourth intron-exon boundary. This process results in Fxr{alpha}1 having an extended N-terminus compared to Fxr{alpha}2. A Gal4DBD-Fxr{alpha}LBD fusion construct was activated by chenodeoxycholic, cholic, deoxycholic and lithocholic acids, and the synthetic agonist GW4064 in transient transactivation assays. Activation of the Gal4DBD-Fxr{alpha}LBD fusion construct was enhanced by addition of PGC-1{alpha}, as demonstrated through titration assays. Surprisingly, when the full-length versions of the two Fxr{alpha} isoforms were compared in transient transfection assays, Fxr{alpha}2 was activated by C{sub 24} bile acids and GW4064, while Fxr{alpha}1 was not significantly activated by any of the compounds tested. Since the only significant difference between the full-length constructs was sequence in the AF1 domain, these experiments highlight a key functional region in the Fxr{alpha} AF1 domain. Furthermore, mammalian two-hybrid studies demonstrated the ability of Fxr{alpha}2, but not Fxr{alpha}1, to interact with PGC-1{alpha} and SRC-1, and supported our results from the transient transfection reporter gene activation assays. These data demonstrate that both mammalian and teleost FXR (Fxr{alpha}2 isoform) are activated by primary and secondary bile acids.

  5. Adiponectin Isoforms and Leptin Impact on Rheumatoid Adipose Mesenchymal Stem Cells Function

    OpenAIRE

    Urszula Skalska; Ewa Kontny

    2016-01-01

    Adiponectin and leptin have recently emerged as potential risk factors in rheumatoid arthritis (RA) pathogenesis. In this study we evaluated the effects of adiponectin and leptin on immunomodulatory function of adipose mesenchymal stem cells (ASCs) derived from infrapatellar fat pad of RA patients. ASCs were stimulated with leptin, low molecular weight (LMW) and high/middle molecular weight (HMW/MMW) adiponectin isoforms. The secretory activity of ASCs and their effect on rheumatoid synovial ...

  6. Immunodetection of nmt55/p54nrb isoforms in human breast cancer

    International Nuclear Information System (INIS)

    We previously identified and characterized a novel 55 kDa nuclear protein, termed nmt55/p54nrb, whose expression was decreased in a subset of human breast tumors. The objective of this study was to determine if this reduced expression in human breast tumors was attributed to the regulation of mRNA transcription or the presence of altered forms of this protein. Northern blot analysis and ribonuclease protection assay indicated that nmt55/p54nrb mRNA is expressed at varying levels in estrogen receptor positive (ER+) and estrogen receptor negative (ER-) human breast tumors suggesting that reduced expression of nmt55/p54nrb protein in ER- tumors was not due to transcriptional regulation. To determine if multiple protein isoforms are expressed in breast cancer, we utilized Western blot and immunohistochemical analyses, which revealed the expression of an nmt55/p54nrb protein isoform in a subset of ER+ tumors. This subset of ER+ human breast tumors expressed an altered form of nmt55/p54nrb that was undetectable with an amino-terminal specific antibody suggesting that this isoform contains alterations or modifications within the amino terminal domain. Our study indicates that nmt55/p54nrb protein is post-transcriptionally regulated in human breast tumors leading to reduced expression in ER- tumors and the expression of an amino terminal altered isoform in a subset of ER+ tumors. The potential involvement of nmt55/p54nrb in RNA binding and pre-mRNA splicing may be important for normal cell growth and function; thus, loss or alteration of protein structure may contribute to tumor growth and progression

  7. Functional studies and expression regulation of two leptin isoforms in grass carp

    OpenAIRE

    Chen, Ting; 陈廷

    2012-01-01

    Leptin, the protein product of obese gene, is a 16-kD adipokine with regulatory functions on food intake and energy metabolism. At present, limited information is available on leptin functions and regulation in lower vertebrates mainly due to the fact that the primary structure of leptin is highly diversified from fish to mammals. Leptin in teleost fish is even more complicated as leptin isoforms have been reported presumably as a result of whole-genome duplication that occurred during the ev...

  8. Contribution of human cytochrome P-450 isoforms to the metabolism of the simplest phenothiazine neuroleptic promazine

    OpenAIRE

    Wójcikowski, Jacek; Pichard-Garcia, Lydiane; Maurel, Patrick; Daniel, Władysława A

    2003-01-01

    The aim of the present study was to identify human cytochrome P-450 isoforms (CYPs) involved in 5-sulphoxidation and N-demethylation of the simplest phenothiazine neuroleptic promazine in human liver.The experiments were performed in the following in vitro models: (A) a study of promazine metabolism in liver microsomes—(a) correlations between the rate of promazine metabolism and the level and activity of CYPs; (b) the effect of specific inhibitors on the rate of promazine metabolism (inhibit...

  9. Decreased Levels of the Gelsolin Plasma Isoform in Patients with Rheumatoid Arthritis

    OpenAIRE

    Osborn, Teresia M.; Verdrengh, Margareta; Stossel, Thomas Peter; Tarkowski, Andrej; Bokarewa, Maria

    2008-01-01

    Introduction Gelsolin is an intracellular actin-binding protein involved in cell shape changes, cell motility, and apoptosis. An extracellular gelsolin isoform, plasma gelsolin circulates in the blood of healthy individuals at a concentration of \\(200 \\pm 50\\) mg/L and has been suggested to be a key component of an extracellular actin-scavenging system during tissue damage. Levels of plasma gelsolin decrease during acute injury and inflammation, and administration of recombinant plasma gelsol...

  10. Most Highly Expressed Protein-Coding Genes Have a Single Dominant Isoform

    OpenAIRE

    Ezkurdia, Iakes; Rodriguez, Jose Manuel; Pau, Enrique Carrillo-de Santa; Vázquez, Jesús; Valencia, Alfonso; Tress, Michael L

    2015-01-01

    Although eukaryotic cells express a wide range of alternatively spliced transcripts, it is not clear whether genes tend to express a range of transcripts simultaneously across cells, or produce dominant isoforms in a manner that is either tissue-specific or regardless of tissue. To date, large-scale investigations into the pattern of transcript expression across distinct tissues have produced contradictory results. Here, we attempt to determine whether genes express a dominant splice variant ...

  11. Revealing the functions of the transketolase enzyme isoforms in Rhodopseudomonas palustris using a systems biology approach.

    Directory of Open Access Journals (Sweden)

    Chia-Wei Hu

    Full Text Available BACKGROUND: Rhodopseudomonas palustris (R. palustris is a purple non-sulfur anoxygenic phototrophic bacterium that belongs to the class of proteobacteria. It is capable of absorbing atmospheric carbon dioxide and converting it to biomass via the process of photosynthesis and the Calvin-Benson-Bassham (CBB cycle. Transketolase is a key enzyme involved in the CBB cycle. Here, we reveal the functions of transketolase isoforms I and II in R. palustris using a systems biology approach. METHODOLOGY/PRINCIPAL FINDINGS: By measuring growth ability, we found that transketolase could enhance the autotrophic growth and biomass production of R. palustris. Microarray and real-time quantitative PCR revealed that transketolase isoforms I and II were involved in different carbon metabolic pathways. In addition, immunogold staining demonstrated that the two transketolase isoforms had different spatial localizations: transketolase I was primarily associated with the intracytoplasmic membrane (ICM but transketolase II was mostly distributed in the cytoplasm. Comparative proteomic analysis and network construction of transketolase over-expression and negative control (NC strains revealed that protein folding, transcriptional regulation, amino acid transport and CBB cycle-associated carbon metabolism were enriched in the transketolase I over-expressed strain. In contrast, ATP synthesis, carbohydrate transport, glycolysis-associated carbon metabolism and CBB cycle-associated carbon metabolism were enriched in the transketolase II over-expressed strain. Furthermore, ATP synthesis assays showed a significant increase in ATP synthesis in the transketolase II over-expressed strain. A PEPCK activity assay showed that PEPCK activity was higher in transketolase over-expressed strains than in the negative control strain. CONCLUSIONS/SIGNIFICANCE: Taken together, our results indicate that the two isoforms of transketolase in R. palustris could affect photoautotrophic growth

  12. Functional demonstrations of starch binding domains present in Ostreococcus tauri starch synthases isoforms

    OpenAIRE

    Barchiesi, Julieta; Hedin, Nicolás; Gomez-Casati, Diego F.; Miguel A Ballicora; Busi, María V.

    2015-01-01

    Background Starch-binding domains are key modules present in several enzymes involved in polysaccharide metabolism. These non-catalytic modules have already been described as essential for starch-binding and the catalytic activity of starch synthase III from the higher plant Arabidopsis thaliana. In Ostreococcus tauri, a unicellular green alga of the Prasinophyceae family, there are three SSIII isoforms, known as Ostta SSIII-A, SSIII-B and SSIII-C. Results In this work, using in silico and in...

  13. VEGF111b, a new member of VEGFxxxb isoforms and induced by mitomycin C, inhibits angiogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Gu, Fang; Li, Xiuli [Department of Obstetrics and Gynecology, Chinese PLA General Hospital, Beijing (China); Kong, Jian [Department of Hepatobiliary Surgery, Beijing Chaoyang Hospital, Capital Medical University, Beijing (China); Pan, Bing [The Institute of Cardiovascular Sciences, Peking University Health Science Center, Key Laboratory of Molecular Cardiovascular Sciences of Education Ministry, Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides of Health Ministry, Beijing (China); Institute of Systems Biomedicine, School of Basic Medical Sciences, Peking University Health Science Center, Key Laboratory of Molecular Cardiovascular Sciences of Education Ministry, Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides of Health Ministry, Beijing (China); Sun, Min [Department of Obstetrics and Gynecology, Tangdu Hospital, Fourth Military Medical University, Xian (China); Zheng, Lemin, E-mail: zhengl@bjmu.edu.cn [The Institute of Cardiovascular Sciences, Peking University Health Science Center, Key Laboratory of Molecular Cardiovascular Sciences of Education Ministry, Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides of Health Ministry, Beijing (China); Institute of Systems Biomedicine, School of Basic Medical Sciences, Peking University Health Science Center, Key Laboratory of Molecular Cardiovascular Sciences of Education Ministry, Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides of Health Ministry, Beijing (China); Yao, Yuanqing, E-mail: yqyao@126.com [Department of Obstetrics and Gynecology, Chinese PLA General Hospital, Beijing (China)

    2013-11-08

    Highlights: •We discovered a new member of VEGFxxxb family-VEGF111b. •We found VEGF111b mRNA and protein can be induced by mitomycin C. •We confirmed VEGF111b over-expression inhibits angiogenesis. •VEGF111b inhibits angiogenesis through inhibiting VEGF-R2/PI3K/Akt and VEGF-R2/ERK1/2 phosphorylation. -- Abstract: Vascular endothelial growth factor (VEGF-A) stimulating angiogenesis is required for tumor growth and progression. The conventional VEGF-A isoforms have been considered as pro-angiogenic factors. Another family of VEGF-A isoforms generated by alternative splicing, termed VEGFxxxb isoforms, has anti-angiogenic property, exemplified by VEGF165b. Here, we identify a new number of VEGFxxx family-VEGF111b induced by mitomycin C, although not detected in mitomycin C-unexposed ovarian cancer cells. SKOV3 cells were transfected with pcDNA{sub 3.1} empty vector, pcDNA{sub 3.1}-VEGF111b or pcDNA{sub 3.1}-VEGF165b to collect conditioned mediums respectively. VEGF111b overexpression inhibits proliferation, migration and tube formation of endothelial cell by inhibiting VEGF-R2 phosphorylation and its downstream signaling, similar to VEGF165b but slightly lower than VEGF165b. The anti-angiogenic property depends on the six amino acids of exon 8b of the VEGFxxxb isoforms. Our results show that VEGF111b is a novel potent anti-angiogenic agent that can target the VEGF-R2 and its signaling pathway to inhibit ovarian tumor growth.

  14. Isoform composition, gene expression and sarcomeric protein phosphorylation in striated muscle of mice after space flight

    Science.gov (United States)

    Vikhlyantsev, Ivan; Ulanova, Anna; Salmov, Nikolay; Gritsyna, Yulia; Bobylev, Alexandr; Rogachevsky, Vadim; Shenkman, Boris; Podlubnaya, Zoya

    Using RT-PCR and SDS-PAGE, changes in isoform composition, gene expression, titin and nebulin phosphorylation, as well as changes in isoform composition of myosin heavy chains in striated muscles of mice were studied after 30-day-long space flight onboard the Russian spacecraft “BION-M” No. 1. The muscle fibre-type shift from slow-to-fast was observed in m. gastrocnemius and m. tibialis anterior of animals from “Flight” group. A decrease in the content of the NT and N2A titin isoforms and nebulin in the skeletal muscles of animals from “Flight” group was found. Meanwhile, significant differences in gene expression of these proteins in skeletal muscles of mice from “Flight” and “Control” groups were not observed. Using Pro-Q Diamond stain, an increase in titin phosphorylation in m. gastrocnemius of mice from “Flight” group was detected. The content of the NT, N2BA and N2B titin isoforms in cardiac muscle of mice from “Flight” and “Control” groups did not differ, nevertheless an increase in titin gene expression in the myocardium of the “Flight” group animals was found. The observed changes will be discussed in the context of theirs role in contractile activity of striated muscles of mice in conditions of weightlessness. This work was supported by the Russian Foundation for Basic Research (grants No. 14-04-32240, 14-04-00112). Acknowledgement. We express our gratitude to the teams of Institute of Biomedical Problems RAS and “PROGRESS” Corporation involved in the preparation of the “BION-M” mission.

  15. Dynamic expression and localization of c-MET isoforms in the developing rat pancreas

    OpenAIRE

    Wu, Yulong; Cheng, Mei; Shi, Zhen; Feng, Zhenqing; Guan, Xiaohong

    2014-01-01

    Pancreata from Sprague Dawley rats of different developmental stages were studied to determine the expression and cellular localization of different c-MET isoforms in the developing rat pancreas. Pancreatic mRNA and protein expression levels of c-MET at different developmental stages from embryo to adult were detected by reverse transcription-polymerase chain reaction and by western blotting. To identify the cellular localization of c-MET protein in the developing rat pancreas, double immunof...

  16. Smoking specifically induces metallothionein-2 isoform in human placenta at term

    International Nuclear Information System (INIS)

    Recently, we reported the presence of higher levels of metallothionein (MT) in placentas of smokers compared to non-smokers. In the present study, we designed experiments to separate and evaluate two isoforms of MT (MT-1 and MT-2) in placentas of smokers and non-smokers. Metallothionein was extracted and separated by ion-exchange high performance liquid chromatography (HPLC), previous saturation with cadmium chloride. Two peaks eluting at 6 and 12.5 min, corresponding to MT-1 and MT-2, respectively, were obtained. Metallothionein present in both peaks was identified by Western blot analysis using a monoclonal antibody directed against MT-1 and MT-2. Each isoform concentration was calculated after measuring its cadmium content by atomic absorption spectrometry with inductively coupled-plasma. In placentas of smokers, MT-2 levels increased by seven-fold compared to non-smokers, whereas MT-1 was not changed. Total placental cadmium and zinc concentrations, determined by atomic absorption spectrometry and neutron activation analysis, respectively, were higher in smokers. Metallothioneins levels were clearly in excess to bind all cadmium ions present in placentas. However, most of placental zinc remains unbound to MTs, although as much as twice zinc ions could be bound to MT in smokers. In conclusion, MT-2 is the main isoform induced by smoking, suggesting that this isoform could be involved in placental cadmium and zinc retention. This fact, which could contribute to reduce the transference of zinc to the fetus, may be associated to detrimental effects on fetal growth and development

  17. DJ-1 isoforms in whole blood as potential biomarkers of Parkinson disease

    OpenAIRE

    Lin, Xiangmin; Cook, Travis J.; Zabetian, Cyrus P.; Leverenz, James B.; Peskind, Elaine R.; Hu, Shu-Ching; Cain, Kevin C.; Pan, Catherine; Edgar, John Scott; Goodlett, David R.; Racette, Brad A.; Checkoway, Harvey; Montine, Thomas J.; Shi, Min; Zhang, Jing

    2012-01-01

    DJ-1 is a multifunctional protein that plays an important role in oxidative stress, cell death, and synucleinopathies, including Parkinson disease. Previous studies have demonstrated that total DJ-1 levels decrease in the cerebrospinal fluid, but do not change significantly in human plasma from patients with Parkinson disease when compared with controls. In this study, we measured total DJ-1 and its isoforms in whole blood of patients with Parkinson disease at various stages, Alzheimer diseas...

  18. Differential susceptibility on myosin heavy chain isoform following eccentric-induced muscle damage

    OpenAIRE

    Choi, Seung Jun

    2014-01-01

    Based on myosin heavy chain (MHC) isoform, human skeletal muscle fibers can be categorized into three fiber types, type I, IIa, IIx fibers, and each fiber type has different characteristics. Typical characteristics are difference in force production, shortening velocity, and fatigue resistance. When the muscle is contract and stretched by a force that is greater than the force generated by the muscle, contraction-induced muscle damage frequently occurs. Several experimental models involving b...

  19. Receptor-isoform-selective insulin analogues give tissue-preferential effects

    DEFF Research Database (Denmark)

    Vienberg, Sara Gry; Bouman, Stephan D; Sørensen, Heidi;

    2011-01-01

    inducing glycogen accumulation (75%) and lipogenesis (130%) than for affecting muscle (45%). For the same blood-glucose-lowering effect upon acute intravenous dosing of mice, INS-B gave a significantly higher degree of IR phosphorylation in liver than HI. These in vitro and in vivo results indicate that...... insulin analogues with IR-isoform-preferential binding affinity are able to elicit tissue-selective biological responses, depending on IR-A/IR-B expression....

  20. Formation of VEGF isoform-specific spatial distributions governing angiogenesis: computational analysis

    Directory of Open Access Journals (Sweden)

    Mac Gabhann Feilim

    2011-05-01

    Full Text Available Abstract Background The spatial distribution of vascular endothelial growth factor A (VEGF is an important mediator of vascular patterning. Previous experimental studies in the mouse hindbrain and retina have suggested that VEGF alternative splicing, which controls the ability of VEGF to bind to heparan sulfate proteoglycans (HSPGs in the extracellular matrix (ECM, plays a key role in controlling VEGF diffusion and gradients in tissues. Conversely, proteolysis notably by matrix metalloproteinases (MMPs, plays a critical role in pathological situations by releasing matrix-sequestered VEGF and modulating angiogenesis. However, computational models have predicted that HSPG binding alone does not affect VEGF localization or gradients at steady state. Results Using a 3D molecular-detailed reaction-diffusion model of VEGF ligand-receptor kinetics and transport, we test alternate models of VEGF transport in the extracellular environment surrounding an endothelial sprout. We show that differences in localization between VEGF isoforms, as observed experimentally in the mouse hindbrain, as well as the ability of proteases to redistribute VEGF in pathological situations, are consistent with a model where VEGF is endogenously cleared or degraded in an isoform-specific manner. We use our predictions of the VEGF distribution to quantify a tip cell's receptor binding and gradient sensing capacity. A novel prediction is that neuropilin-1, despite functioning as a coreceptor to VEGF165-VEGFR2 binding, reduces the ability of a cell to gauge the relative steepness of the VEGF distribution. Comparing our model to available in vivo vascular patterning data suggests that vascular phenotypes are most consistently predicted at short range by the soluble fraction of the VEGF distributions, or at longer range by matrix-bound VEGF detected in a filopodia-dependent manner. Conclusions Isoform-specific VEGF degradation provides a possible explanation for numerous examples

  1. PPARγ isoforms differentially regulate metabolic networks to mediate mouse prostatic epithelial differentiation

    OpenAIRE

    Strand, D.W.; Jiang, M; Murphy, T A; Yi, Y.; Konvinse, K C; Franco, O E; Wang, Y.; Young, J D; Hayward, S.W.

    2012-01-01

    Recent observations indicate prostatic diseases are comorbidities of systemic metabolic dysfunction. These discoveries revealed fundamental questions regarding the nature of prostate metabolism. We previously showed that prostate-specific ablation of PPARγ in mice resulted in tumorigenesis and active autophagy. Here, we demonstrate control of overlapping and distinct aspects of prostate epithelial metabolism by ectopic expression of individual PPARγ isoforms in PPARγ knockout prostate epithel...

  2. An innovative approach for the characterization of the isoforms of a monoclonal antibody product

    OpenAIRE

    Sundaram, Shanmuuga; Matathia, Alice; Qian, Jun; Zhang, Jingming; Hsieh, Ming-Ching; Liu, Tun; Crowley, Richard; Parekh, Babita; Zhou, Qinwei

    2011-01-01

    Protein biopharmaceuticals, such as monoclonal antibodies (mAbs) are widely used for the prevention and treatment of various diseases. The complex and lengthy upstream and downstream production methods of the antibodies make them susceptible to physical and chemical modifications. Several IgG1 immunoglobulins are used as medical agents for the treatment of colon, breast and head and neck cancers, and at least four to eight isoforms exist in the products. The regulatory agencies understand the...

  3. iReckon: Simultaneous isoform discovery and abundance estimation from RNA-seq data

    OpenAIRE

    Mezlini, Aziz M.; Smith, Eric J. M.; Fiume, Marc; Buske, Orion; Savich, Gleb L.; Shah, Sohrab; Aparicio, Sam; Chiang, Derek Y.; Goldenberg, Anna; Brudno, Michael

    2013-01-01

    High-throughput RNA sequencing (RNA-seq) promises to revolutionize our understanding of genes and their role in human disease by characterizing the RNA content of tissues and cells. The realization of this promise, however, is conditional on the development of effective computational methods for the identification and quantification of transcripts from incomplete and noisy data. In this article, we introduce iReckon, a method for simultaneous determination of the isoforms and estimation of th...

  4. Heterogeneity of serum gelatinases MMP-2 and MMP-9 isoforms and charge variants.

    Science.gov (United States)

    Rossano, Rocco; Larocca, Marilena; Riviello, Lea; Coniglio, Maria Gabriella; Vandooren, Jennifer; Liuzzi, Grazia Maria; Opdenakker, Ghislain; Riccio, Paolo

    2014-02-01

    The matrix metalloproteinases (MMPs) gelatinase A (MMP-2) and gelatinase B (MMP-9) are mediators of brain injury in multiple sclerosis (MS) and valuable biomarkers of disease activity. We applied bidimensional zymography (2-DZ) as an extension of classic monodimensional zymography (1-DZ) to analyse the complete pattern of isoforms and post-translational modifications of both MMP-9 and MMP-2 present in the sera of MS patients. The enzymes were separated on the basis of their isoelectric points (pI) and apparent molecular weights (Mw) and identified both by comparison with standard enzyme preparations and by Western blot analysis. Two MMP-2 isoforms, and at least three different isoforms and two different states of organization of MMP-9 (the multimeric MMP-9 and the N-GAL-MMP-9 complex) were observed. In addition, 2-DZ revealed for the first time that all MMP-9 and MMP-2 isoforms actually exist in the form of charge variants: four or five variants in the NGAL complex, more charge variants in the case of MMP-9; and five to seven charge variants for MMP-2. Charge variants were also observed in recombinant enzymes and, after concentration, also in sera from healthy individuals. Sialylation (MMP-9) and phosphorylation (MMP-2) contributed to molecular heterogeneity. The detection of charge variants of MMP-9 and MMP-2 in MS serum samples illustrates the power of 2-DZ and demonstrates that in previous studies MMP mixtures, rather than single molecules, were analysed. These observations open perspectives for better diagnosis and prognosis of many diseases and need to be critically interpreted when applying other methods for MS and other diseases. PMID:24616914

  5. Characterization of Alien isoforms in vertebrates : Caracterización de isoformas de Alien en vertebrados

    OpenAIRE

    Tenbaum, Stephan

    2002-01-01

    Alien protein isoforms have been described to be involved in a number of biological processes. Alienalpha is a corepressor of the thyroid hormone receptor mediating transcriptional repression in a ligand-sensitive manner. Furthermore, Alienalpha is a corepressor for the orphan receptor DAX1 and the vitamin-D3 receptor. Alienbetta/CSN2 is part of the COP9-signalosome complex that acts in protein phosphorylation, protein degradation and cell cycle regulation. The major goal of this...

  6. VEGF111b, a new member of VEGFxxxb isoforms and induced by mitomycin C, inhibits angiogenesis

    International Nuclear Information System (INIS)

    Highlights: •We discovered a new member of VEGFxxxb family-VEGF111b. •We found VEGF111b mRNA and protein can be induced by mitomycin C. •We confirmed VEGF111b over-expression inhibits angiogenesis. •VEGF111b inhibits angiogenesis through inhibiting VEGF-R2/PI3K/Akt and VEGF-R2/ERK1/2 phosphorylation. -- Abstract: Vascular endothelial growth factor (VEGF-A) stimulating angiogenesis is required for tumor growth and progression. The conventional VEGF-A isoforms have been considered as pro-angiogenic factors. Another family of VEGF-A isoforms generated by alternative splicing, termed VEGFxxxb isoforms, has anti-angiogenic property, exemplified by VEGF165b. Here, we identify a new number of VEGFxxx family-VEGF111b induced by mitomycin C, although not detected in mitomycin C-unexposed ovarian cancer cells. SKOV3 cells were transfected with pcDNA3.1 empty vector, pcDNA3.1-VEGF111b or pcDNA3.1-VEGF165b to collect conditioned mediums respectively. VEGF111b overexpression inhibits proliferation, migration and tube formation of endothelial cell by inhibiting VEGF-R2 phosphorylation and its downstream signaling, similar to VEGF165b but slightly lower than VEGF165b. The anti-angiogenic property depends on the six amino acids of exon 8b of the VEGFxxxb isoforms. Our results show that VEGF111b is a novel potent anti-angiogenic agent that can target the VEGF-R2 and its signaling pathway to inhibit ovarian tumor growth

  7. SASD: the Synthetic Alternative Splicing Database for identifying novel isoform from proteomics

    OpenAIRE

    Zhang, Fan; Drabier, Renee

    2013-01-01

    Background Alternative splicing is an important and widespread mechanism for generating protein diversity and regulating protein expression. High-throughput identification and analysis of alternative splicing in the protein level has more advantages than in the mRNA level. The combination of alternative splicing database and tandem mass spectrometry provides a powerful technique for identification, analysis and characterization of potential novel alternative splicing protein isoforms from pro...

  8. Characterization of fusion genes and the significantly expressed fusion isoforms in breast cancer by hybrid sequencing

    OpenAIRE

    Weirather, Jason L.; Afshar, Pegah Tootoonchi; Clark, Tyson A.; Tseng, Elizabeth; Powers, Linda S.; Underwood, Jason G; Zabner, Joseph; Korlach, Jonas; Wong, Wing Hung; Au, Kin Fai

    2015-01-01

    We developed an innovative hybrid sequencing approach, IDP-fusion, to detect fusion genes, determine fusion sites and identify and quantify fusion isoforms. IDP-fusion is the first method to study gene fusion events by integrating Third Generation Sequencing long reads and Second Generation Sequencing short reads. We applied IDP-fusion to PacBio data and Illumina data from the MCF-7 breast cancer cells. Compared with the existing tools, IDP-fusion detects fusion genes at higher precision and ...

  9. Semisynthetic and Natural Garcinoic Acid Isoforms as New mPGES-1 Inhibitors.

    Science.gov (United States)

    Alsabil, Khaled; Suor-Cherer, Sorphon; Koeberle, Andreas; Viault, Guillaume; Lavaud, Alexis; Temml, Veronika; Waltenberger, Birgit; Schuster, Daniela; Litaudon, Marc; Lorkowski, Stefan; de Vaumas, René; Helesbeux, Jean-Jacques; Guilet, David; Stuppner, Hermann; Werz, Oliver; Seraphin, Denis; Richomme, Pascal

    2016-07-01

    Over the last twenty years, tocotrienol analogues raised great interest because of their higher level and larger domain of biological activities when compared with tocopherols. Amongst the most promising therapeutic application, anti-inflammatory potency has been evaluated through the inhibition of various mediators of inflammation. Here, we worked on the isolation of two natural isoforms of garcinoic acid (i.e., δ and γ) from two different sources, respectively, Garcinia kola seeds and Garcinia amplexicaulis bark. We also developed semisynthetic strategies to access the other two non-natural α- and β-garcinoic acid isoforms. In the next stage of our work, microsomal prostaglandin E2 synthase was defined as a target to evaluate the anti-inflammatory potential of the four garcinoic acid isomers. Both dimethylated isoforms, β- and γ-garcinoic acid, exhibited the lowest IC50, 2.8 µM and 2.0 µM, respectively. These results showed that the affinity of tocotrienol analogues to microsomal prostaglandin E2 synthase-1 most probably contributes to the anti-inflammatory potential of this class of derivatives. PMID:27286327

  10. MXI1-0, an Alternatively Transcribed Mxi1 Isoform, Is Overexpressed in Glioblastomas

    Directory of Open Access Journals (Sweden)

    Lars D. Engstrom

    2004-09-01

    Full Text Available The c-Myc transcription factor regulates expression of genes related to cell growth, division, and apoptosis. Will, a member of the Mad family, represses transcription of c-Myc-regulated genes by mediating chromatin condensation via histone deacetylase and the Sin3 corepressor. Mxi1 is a c-Myc antagonist and suppresses cell proliferation in vitro. Here, we describe the identification of MXI1-0, a novel Mxi1 isoform that is alternatively transcribed from an upstream exon. MXI1-0 and Mxi1 have different amino-terminal sequences, but share identical Max- and DNA-binding domains. Both isoforms are able to bind Max, to recognize E-box binding sites, and to interact with Sin3. Despite these similarities and in contrast to Will, MXl10 is predominantly localized to the cytoplasm and fails to repress c-Myc-dependent transcription. Although MXI1-0 and Mxi1 are coexpressed in both human and mouse cells, the relative levels of MXI1-0 are higher in primary glioblastoma tumors than in normal brain tissue. This variation in the levels of MXI1-0 and Mxi1 suggests that MXI1-0 may modulate the Myc-inhibitory activity of Will. The identification of MXI1-0 as an alternatively transcribed Mxi1 isoform has significant implications for the interpretation of previous Mxi1 studies, particularly those related to the phenotype of the mxi1 knockout mouse.

  11. Peroxiredoxin isoforms are associated with cardiovascular risk factors in type 2 diabetes mellitus

    Energy Technology Data Exchange (ETDEWEB)

    El Eter, E. [Physiology Department, Faculty of Medicine, King Saud University, Riyadh (Saudi Arabia); Cardiovascular Research Group, Faculty of Medicine, King Saud University, Riyadh (Saudi Arabia); Physiology Department, Faculty of Medicine, Alexandria University, Alexandria (Egypt); Al-Masri, A.A. [Physiology Department, Faculty of Medicine, King Saud University, Riyadh (Saudi Arabia); Cardiovascular Research Group, Faculty of Medicine, King Saud University, Riyadh (Saudi Arabia)

    2015-03-03

    The production of oxygen free radicals in type 2 diabetes mellitus contributes to the development of complications, especially the cardiovascular-related ones. Peroxiredoxins (PRDXs) are antioxidant enzymes that combat oxidative stress. The aim of this study was to investigate the associations between the levels of PRDX isoforms (1, 2, 4, and 6) and cardiovascular risk factors in type 2 diabetes mellitus. Fifty-three patients with type 2 diabetes mellitus (28F/25M) and 25 healthy control subjects (7F/18M) were enrolled. We measured the plasma levels of each PRDX isoform and analyzed their correlations with cardiovascular risk factors. The plasma PRDX1, -2, -4, and -6 levels were higher in the diabetic patients than in the healthy control subjects. PRDX2 and -6 levels were negatively correlated with diastolic blood pressure, fasting blood sugar, and hemoglobin A1c. In contrast, PRDX1 levels were positively correlated with low-density lipoprotein and C-reactive protein levels. PRDX4 levels were negatively correlated with triglycerides. In conclusion, PRDX1, -2, -4, and -6 showed differential correlations with a variety of traditional cardiovascular risk factors. These results should encourage further research into the crosstalk between PRDX isoforms and cardiovascular risk factors.

  12. Expression of Monocarboxylate Transporter Isoforms in Rat Skeletal Muscle Under Hypoxic Preconditioning and Endurance Training.

    Science.gov (United States)

    Saxena, Saurabh; Shukla, Dhananjay; Bansal, Anju

    2016-03-01

    Previously, we have reported the regulation of monocarboxylate transporters (MCT)1 and MCT4 by physiological stimuli such as hypoxia and exercise. In the present study, we have evaluated the effect of hypoxic preconditioning and training on expression of different MCT isoforms in muscles. We found the increased mRNA expression of MCT1, MCT11, and MCT12 after hypoxic preconditioning with cobalt chloride and training. However, the expression of other MCT isoforms increased marginally or even reduced after hypoxic preconditioning. Only the protein expression of MCT1 increased after hypoxia preconditioning. MCT2 protein expression increased after training only and MCT4 protein expression decreased both in preconditioning and hypoxic training. Furthermore, we found decreased plasma lactate level during hypoxia preconditioning (0.74-fold), exercise (0.78-fold), and hypoxia preconditioning along with exercise (0.67-fold), which indicates increased lactate uptake by skeletal muscle. The protein-protein interactions with hypoxia inducible factor-1 and MCT isoforms were also evaluated, but no interaction was found. In conclusion, we say that almost all MCTs are expressed in red gastrocnemius muscle at the mRNA level and their expression is regulated differently under hypoxia preconditioning and exercise condition. PMID:26716978

  13. Contribution of human hepatic cytochrome p450 isoforms to the metabolism of psychotropic drugs.

    Science.gov (United States)

    Niwa, Toshiro; Shiraga, Toshifumi; Ishii, Ikuko; Kagayama, Akira; Takagi, Akira

    2005-09-01

    The metabolic activities of six psychotropic drugs, diazepam, clotiazepam, tofisopam, etizolam, tandospirone, and imipramine, were determined for 14 isoforms of recombinant human hepatic cytochrome P450s (CYPs) and human liver microsomes by measuring the disappearance rate of parent compounds. In vitro kinetic studies revealed that Vmax/Km values in human liver microsomes were the highest for tofisopam, followed by tandospirone>clotiazepam>imipramine, diazepam, and etizolam. Among the recombinant CYPs, CYP3A4 exhibited the highest metabolic activities of all compounds except for clotiazepam and imipramine. The metabolism of clotiazepam was catalyzed by CYP2B6, CYP3A4, CYP2C18, and CYP2C19, and imipramine was metabolized by CYP2D6 most efficiently. In addition, the metabolic activities of diazepam, clotiazepam, and etizolam in human liver microsomes were inhibited by 2.5 microM ketoconazole, a CYP3A4 inhibitor, by 97.5%, 65.1%, and 83.5%, respectively, and the imipramine metabolism was not detected after the addition of 1 or 10 microM quinidine, a CYP2D6 inhibitor. These results suggest that the psychotropic drugs investigated are metabolized predominantly by CYP3A4, except that CYP2D6 catalyzes the metabolism of imipramine. In addition, this approach based on the disappearance rate appears to be useful for the identification of the responsible CYP isoform(s) of older drugs, for which metabolic profiles have not been reported. PMID:16141545

  14. Peroxiredoxin isoforms are associated with cardiovascular risk factors in type 2 diabetes mellitus

    International Nuclear Information System (INIS)

    The production of oxygen free radicals in type 2 diabetes mellitus contributes to the development of complications, especially the cardiovascular-related ones. Peroxiredoxins (PRDXs) are antioxidant enzymes that combat oxidative stress. The aim of this study was to investigate the associations between the levels of PRDX isoforms (1, 2, 4, and 6) and cardiovascular risk factors in type 2 diabetes mellitus. Fifty-three patients with type 2 diabetes mellitus (28F/25M) and 25 healthy control subjects (7F/18M) were enrolled. We measured the plasma levels of each PRDX isoform and analyzed their correlations with cardiovascular risk factors. The plasma PRDX1, -2, -4, and -6 levels were higher in the diabetic patients than in the healthy control subjects. PRDX2 and -6 levels were negatively correlated with diastolic blood pressure, fasting blood sugar, and hemoglobin A1c. In contrast, PRDX1 levels were positively correlated with low-density lipoprotein and C-reactive protein levels. PRDX4 levels were negatively correlated with triglycerides. In conclusion, PRDX1, -2, -4, and -6 showed differential correlations with a variety of traditional cardiovascular risk factors. These results should encourage further research into the crosstalk between PRDX isoforms and cardiovascular risk factors

  15. DJ-1 isoforms in whole blood as potential biomarkers of Parkinson disease

    Science.gov (United States)

    Lin, Xiangmin; Cook, Travis J.; Zabetian, Cyrus P.; Leverenz, James B.; Peskind, Elaine R.; Hu, Shu-Ching; Cain, Kevin C.; Pan, Catherine; Edgar, John Scott; Goodlett, David R.; Racette, Brad A.; Checkoway, Harvey; Montine, Thomas J.; Shi, Min; Zhang, Jing

    2012-01-01

    DJ-1 is a multifunctional protein that plays an important role in oxidative stress, cell death, and synucleinopathies, including Parkinson disease. Previous studies have demonstrated that total DJ-1 levels decrease in the cerebrospinal fluid, but do not change significantly in human plasma from patients with Parkinson disease when compared with controls. In this study, we measured total DJ-1 and its isoforms in whole blood of patients with Parkinson disease at various stages, Alzheimer disease, and healthy controls to identify potential peripheral biomarkers of PD. In an initial discovery study of 119 subjects, 7 DJ-1 isoforms were reliably detected, and blood levels of those with 4-hydroxy-2-nonenal modifications were discovered to be altered in late-stage Parkinson disease. This result was further confirmed in a validation study of another 114 participants, suggesting that, unlike total DJ-1 levels, post-translationally modified isoforms of DJ-1 from whole blood are candidate biomarkers of late-stage Parkinson disease. PMID:23233873

  16. Role of p73 Dinucleotide Polymorphism in Prostate Cancer and p73 Protein Isoform Balance

    Directory of Open Access Journals (Sweden)

    L. Michael Carastro

    2014-01-01

    Full Text Available Background. Molecular markers for prostate cancer (PCa risks are currently lacking. Here we address the potential association of a dinucleotide polymorphism (DNP in exon 2 of the p73 gene with PCa risk/progression and discern any disruption of p73 protein isoforms levels in cells harboring a p73 DNP allele. Methods. We investigated the association between p73 DNP genotype and PCa risk/aggressiveness and survival by fitting logistic regression models in 1,292 incident cases and 682 controls. Results. Although we detected no association between p73 DNP and PCa risk, a significant inverse relationship between p73 DNP and PCa aggressiveness (AT/AT + GC/AT versus GC/GC, OR = 0.55, 95%Cl = 0.31–0.99 was detected. Also, p73 DNP is marginally associated with overall death (dominant model, HR = 0.76, 95%Cl = 0.57–1.00, P=0.053 as well as PCa specific death (HR = 0.69, 95%Cl = 0.45–1.06, P=0.09. Western blot analyses for p73 protein isoforms indicate that cells heterozygous for the p73 DNP have lower levels of ∆Np73 relative to TAp73 (P<0.001. Conclusions. Our findings are consistent with an association between p73 DNP and low risk for PCa aggressiveness by increasing the expressed TAp73/∆Np73 protein isoform ratio.

  17. Characterization of protein kinase C and its isoforms in human T lymphocytes.

    Science.gov (United States)

    Beyers, A D; Hanekom, C; Rheeder, A; Strachan, A F; Wooten, M W; Nel, A E

    1988-11-15

    Protein kinase C (PKC) regulates numerous T cell functions and is present in abundance in normal human T cells and certain T cell lines. Although crude Triton X-100 soluble material obtained from T cell pellets contains minimal PKC activity, DEAE chromatography revealed that 12 to 37% of cellular PKC was membrane associated, probably due to removal of an inhibitor through column chromatography. As in other tissues, PKC from lymphoid tissue was phospholipid and Ca2+ dependent and diolein reduced the Ca2+ requirements for enzyme activity. Hydroxylapatite chromatography revealed that T cells possess two major peaks of PKC activity. Although, the enzyme in these peaks had similar m.w. and identical iso-electric mobility, the proteins differed with respect to their autophosphorylation sites and immunoreactivity toward an isoform specific antibody. Furthermore, differences in their activities in the presence of phospholipid, diolein, and limiting amounts of Ca2+ imply that these isoforms may be differentially activated. We discuss optimal conditions for activation of PKC and its isoforms for study of T lymphocyte cellular function. PMID:3263426

  18. Duplicated CFTR isoforms in eels diverged in regulatory structures and osmoregulatory functions.

    Science.gov (United States)

    Wong, Marty Kwok-Shing; Pipil, Supriya; Kato, Akira; Takei, Yoshio

    2016-09-01

    Two cystic fibrosis transmembrane conductance regulator (CFTR) isoforms, CFTRa and CFTRb, were cloned in Japanese eel and their structures and functions were studied in different osmoregulatory tissues in freshwater (FW) and seawater (SW) eels. Molecular phylogenetic results suggested that the CFTR duplication in eels occurred independently of the duplication event in salmonid. CFTRa was expressed in the intestine and kidney and downregulated in both tissues in SW eels, while CFTRb was specifically expressed in the gill and greatly upregulated in SW eels. Structurally, the CFTR isoforms are similar in most functional domains except the regulatory R domain, where the R domain of CFTRa is similar to that of human CFTR but the R domain of CFTRb is unique in having high intrinsic negative charges and fewer phosphorylation sites, suggesting divergence of isoforms in terms of gating properties and hormonal regulation. Immunohistochemical results showed that CFTR was localized on the apical regions of SW ionocytes, suggesting a Cl(-) secretory role as in other teleosts. In intestine and kidney, however, immunoreactive CFTR was mostly found in the cytosolic vesicles in FW eels, indicating that Cl(-) channel activity could be low at basal conditions, but could be rapidly increased by membrane insertion of the stored channels. Guanylin (GN), a known hormone that increases CFTR activity in mammalian intestine, failed to redistribute CFTR and to affect its expression in eel intestine. The results suggested that GN-independent CFTR regulation is present in eel intestine and kidney. PMID:27322796

  19. Accumulation of cyclophilin A isoforms in conditioned medium of irradiated breast cancer cells

    International Nuclear Information System (INIS)

    Secreted proteins play a key role in cell signaling and communication. We recently showed that ionizing radiations induced a delayed cell death of breast cancer cells, mediated by the death receptor pathways through the expression of soluble forms of 'death ligands'. Using the same cell model, the objective of our work was the identification of diffusible factors, secreted following cell irradiation, potentially involved in cell death signaling. Differential proteomics analysis of conditioned media using 2DE resulted in detection of numerous spots that were significantly modulated following cell irradiation. The corresponding proteins were identified using MALDI-TOF MS and LC-MS/MS approaches. Interestingly, five isoforms of cyclophilin A were observed as increased in conditioned medium of irradiated cells. These isoforms differed in isoelectric points and in accumulation levels. An increase of cyclophilin A secretion was confirmed by Western blotting of conditioned media of irradiated or radiosensitive mammary cells. These isoforms displayed an interesting pattern of protein maturation and post-translational modifications, including an alternating removal of N-terminal methionine, associated with a combination of acetylations and methylations. The role of the protein is discussed in relation with its potential involvement in the mechanisms of inter-cells relationships and radiosensitivity. (authors)

  20. Estrogen receptor isoforms and progestin hormone dependence in a mouse mammary tumor model.

    Science.gov (United States)

    Actis, A M; Caruso, S P; Levin, E

    1994-09-01

    The close interaction between receptors and other transcription factors suggests that their corresponding transducing signals can trigger functional and structural changes in other related molecules. The effect of a progestinic agent, medroxyprogesterone acetate (MPA), on some of the estrogen-receptor (ER) parameters was studied in 2 murine mammary tumor sublines with different progestin hormone dependence for their respective growth. The relative binding affinity of estradiol and tamoxifen for the ER, the receptor content and the ER isoforms studied by HPLC were determined in the hormone-autonomous (HA) and the hormone-dependent (HD) tumor sublines. In the HA subline administration of MPA did not modify the tumor growth rate, whereas this was accelerated in the HD subline. The ER content was clearly increased in the HD tumor subline, but not in the HA subline, compared with the untreated controls. In contrast, the E2 and tamoxifen relative binding affinity for the ER and the isoform profiles were affected by MPA treatment in the HA, but not in the HD tumor subline. The functional change (decrease in relative binding affinity) can be attributed to the appearance of a lower-molecular-size ER isoform under the progestinic treatment. Modifications in one receptor molecule by the action of ligands corresponding to another type of receptor show the interconection between transcription factors and the necessity of broadening conventional concepts regarding hormone dependence in mammary tumorigenesis. PMID:8077051

  1. Differential expression of a new isoform of DLG2 in renal oncocytoma

    Directory of Open Access Journals (Sweden)

    Kovacs Gyula

    2006-04-01

    Full Text Available Abstract Background Renal oncocytoma, a benign tumour of the kidney, may pose a differential diagnostic problem due to overlapping phenotype with chromophobe renal cell carcinoma or other types of renal cell tumours. Therefore, identification of molecular markers would be of great value for molecular diagnostics of this tumour type. Methods In the current study we applied various techniques, including Affymetrix microarray hybridization and semiquantitative RT-PCR, to identify genes expressed differentially in renal oncocytomas. Subsequently, we used RACE and Northern blot hybridization to characterize the potential candidates for molecular diagnosis. Results We have identified new isoform of DLG2 gene, which contains 3'-end exons of the known DLG2 gene along with the hypothetical gene FLJ37266. The new isoform is specifically upregulated in renal oncocytoma, whereas the known DLG2 gene is downregulated in this type of kidney tumour. Conclusion The new isoform of DLG2 is the promising candidate gene for molecular differential diagnostics of renal oncocytoma.

  2. Alternative Splicing Generates Different Parkin Protein Isoforms: Evidences in Human, Rat, and Mouse Brain

    Directory of Open Access Journals (Sweden)

    Soraya Scuderi

    2014-01-01

    Full Text Available Parkinson protein 2, E3 ubiquitin protein ligase (PARK2 gene mutations are the most frequent causes of autosomal recessive early onset Parkinson’s disease and juvenile Parkinson disease. Parkin deficiency has also been linked to other human pathologies, for example, sporadic Parkinson disease, Alzheimer disease, autism, and cancer. PARK2 primary transcript undergoes an extensive alternative splicing, which enhances transcriptomic diversification. To date several PARK2 splice variants have been identified; however, the expression and distribution of parkin isoforms have not been deeply investigated yet. Here, the currently known PARK2 gene transcripts and relative predicted encoded proteins in human, rat, and mouse are reviewed. By analyzing the literature, we highlight the existing data showing the presence of multiple parkin isoforms in the brain. Their expression emerges from conflicting results regarding the electrophoretic mobility of the protein, but it is also assumed from discrepant observations on the cellular and tissue distribution of parkin. Although the characterization of each predicted isoforms is complex, since they often diverge only for few amino acids, analysis of their expression patterns in the brain might account for the different pathogenetic effects linked to PARK2 gene mutations.

  3. A novel FADS1 isoform potentiates FADS2-mediated production of eicosanoid precursor fatty acids.

    Science.gov (United States)

    Park, Woo Jung; Kothapalli, Kumar S D; Reardon, Holly T; Lawrence, Peter; Qian, Shu-Bing; Brenna, J Thomas

    2012-08-01

    The fatty acid desaturase (FADS) genes code for the rate-limiting enzymes required for the biosynthesis of long-chain polyunsaturated fatty acids (LCPUFA). Here we report discovery and function of a novel FADS1 splice variant. FADS1 alternative transcript 1 (FADS1AT1) enhances desaturation of FADS2, leading to increased production of eicosanoid precursors, the first case of an isoform modulating the enzymatic activity encoded by another gene. Multiple protein isoforms were detected in primate liver, thymus, and brain. In human neuronal cells, their expression patterns are modulated by differentiation and result in alteration of cellular fatty acids. FADS1, but not FADS1AT1, localizes to endoplasmic reticulum and mitochondria. Ribosomal footprinting demonstrates that all three FADS genes are translated at similar levels. The noncatalytic regulation of FADS2 desaturation by FADS1AT1 is a novel, plausible mechanism by which several phylogenetically conserved FADS isoforms may regulate LCPUFA biosynthesis in a manner specific to tissue, organelle, and developmental stage. PMID:22619218

  4. Changes in the expression of NO synthase isoforms after ozone: the effects of allergen exposure

    Directory of Open Access Journals (Sweden)

    Lee June-Hyuk

    2004-06-01

    Full Text Available Abstract Background The functional role of nitric oxide (NO and various nitric oxide synthase (NOS isoforms in asthma remains unclear. Objective This study investigated the effects of ozone and ovalbumin (OVA exposure on NOS isoforms. Methods The expression of inducible NOS (iNOS, neuronal NOS (nNOS, and endothelial NOS (eNOS in lung tissue was measured. Enhanced pause (Penh was measured as a marker of airway obstruction. Nitrate and nitrite in bronchoalveolar lavage (BAL fluid were measured using a modified Griess reaction. Results The nitrate concentration in BAL fluid from the OVA-sensitized/ozone-exposed/OVA-challenged group was greater than that of the OVA-sensitized/saline-challenged group. Methacholine-induced Penh was increased in the OVA-sensitized/ozone-exposed/OVA-challenged group, with a shift in the dose-response curve to the left, compared with the OVA-sensitized/saline-challenged group. The levels of nNOS and eNOS were increased significantly in the OVA-sensitized/ozone-exposed/OVA-challenged group and the iNOS levels were reduced compared with the OVA-sensitized/saline-challenged group. Conclusion In mice, ozone is associated with increases in lung eNOS and nNOS, and decreases in iNOS. None of these enzymes are further affected by allergens, suggesting that the NOS isoforms play different roles in airway inflammation after ozone exposure.

  5. 55K isoform of CDK9 associates with Ku70 and is involved in DNA repair

    International Nuclear Information System (INIS)

    Positive elongation factor b (P-TEFb) is a cellular protein kinase that is required for RNA polymerase II (RNAP II) transcriptional elongation of protein coding genes. P-TEFb is a set of different molecular complexes, each containing CDK9 as the catalytic subunit. There are two isoforms of the CDK9 protein - the major 42 KDa CDK9 isoform and the minor 55KDa isoform that is translated from an in-frame mRNA that arises from an upstream transcriptional start site. We found that shRNA depletion of the 55K CDK9 protein in HeLa cells induces apoptosis and double-strand DNA breaks (DSBs). The levels of apoptosis and DSBs induced by the depletion were reduced by expression of a 55K CDK9 protein variant resistant to the shRNA, indicating that these phenotypes are the consequence of depletion of the 55K protein and not off-target effects. We also found that the 55K CDK9 protein, but not the 42K CDK9 protein, specifically associates with Ku70, a protein involved in DSB repair. Our findings suggest that the 55K CDK9 protein may function in repair of DNA through an association with Ku70.

  6. Multiple tissue-specific isoforms of sulfatide activate CD1d-restricted type II NKT cells

    DEFF Research Database (Denmark)

    Blomqvist, Maria; Rhost, Sara; Teneberg, Susann;

    2009-01-01

    relevant isoforms C24:1 and C24:0, major constituents of the myelin sheet of the nervous system, and C16:0, prominent in the pancreatic islet beta-cells. The most potent sulfatide isoform was lysosulfatide (lacking a fatty acid). Shortened fatty acid chain length (C24:1 versus C18:1), or saturation of the...... mixture of sulfatide isoforms, i.e. sulfatide molecules with different long-chain bases and fatty acid chain lengths and saturation. Here, we demonstrate that sulfatide-specific CD1d-restricted murine NKT hybridomas recognized several different sulfatide isoforms. These included the physiologically...... long fatty acid (C24:0), resulted in reduced stimulatory capacity, and fatty acid hydroxylation abolished the response. Moreover, sulfatide was not responsible for the natural autoreactivity toward splenocytes by XV19 T hybridoma cells. Our results reveal a promiscuity in the recognition of sulfatide...

  7. EXAFS analysis of a human Cu,Zn SOD isoform focused using non-denaturing gel electrophoresis

    International Nuclear Information System (INIS)

    Isoelectric point isoforms of a metalloprotein, copper-zinc superoxide dismutase (CuZnSOD), separated on electrophoresis gels were analyzed using X-ray Absorption Spectroscopy. Mutations of this protein are involved in familial cases of amyotrophic lateral sclerosis. The toxicity of mutants could be relied to defects in the metallation state. Our purpose is to establish analytical protocols to study metallation state of protein isoforms such as those from CuZnSOD. We previously highlighted differences in the copper oxidation state between CuZnSOD isoforms using XANES. Here, we present the first results for EXAFS analyses performed at Cu and Zn K-edge on the majoritary expressed isoform of human CuZnSOD separated on electrophoresis gels.

  8. Correlation analysis of p53 protein isoforms with NPM1/FLT3 mutations and therapy response in acute myeloid leukemia.

    Science.gov (United States)

    Ånensen, N; Hjelle, S M; Van Belle, W; Haaland, I; Silden, E; Bourdon, J-C; Hovland, R; Taskén, K; Knappskog, S; Lønning, P E; Bruserud, Ø; Gjertsen, B T

    2012-03-22

    The wild-type tumor-suppressor gene TP53 encodes several isoforms of the p53 protein. However, while the role of p53 in controlling normal cell cycle progression and tumor suppression is well established, the clinical significance of p53 isoform expression is unknown. A novel bioinformatic analysis of p53 isoform expression in 68 patients with acute myeloid leukemia revealed distinct p53 protein biosignatures correlating with clinical outcome. Furthermore, we show that mutated FLT3, a prognostic marker for short survival in AML, is associated with expression of full-length p53. In contrast, mutated NPM1, a prognostic marker for long-term survival, correlated with p53 isoforms β and γ expression. In conclusion, p53 biosignatures contain useful information for cancer evaluation and prognostication. PMID:21860418

  9. Discovery of naturally occurring splice variants of the rat histamine H3 receptor that act as dominant-negative isoforms.

    Science.gov (United States)

    Bakker, Remko A; Lozada, Adrian Flores; van Marle, André; Shenton, Fiona C; Drutel, Guillaume; Karlstedt, Kaj; Hoffmann, Marcel; Lintunen, Minnamaija; Yamamoto, Yumiko; van Rijn, Richard M; Chazot, Paul L; Panula, Pertti; Leurs, Rob

    2006-04-01

    We described previously the cDNA cloning of three functional rat histamine H3 receptor (rH3R) isoforms as well as the differential brain expression patterns of their corresponding mRNAs and signaling properties of the resulting rH3A, rH3B, and rH3C receptor isoforms (Mol Pharmacol 59:1-8). In the current report, we describe the cDNA cloning, mRNA localization in the rat central nervous system, and pharmacological characterization of three additional rH3R splice variants (rH3D, rH3E, and rH3F) that differ from the previously published isoforms in that they result from an additional alternative-splicing event. These new H3R isoforms lack the seventh transmembrane (TM) helix and contain an alternative, putatively extracellular, C terminus (6TM-rH3 isoforms). After heterologous expression in COS-7 cells, radioligand binding or functional responses upon the application of various H3R ligands could not be detected for the 6TM-rH3 isoforms. In contrast to the rH3A receptor (rH3AR), detection of the rH3D isoform using hemagglutinin antibodies revealed that the rH3D isoform remains mainly intracellular. The expression of the rH3D-F splice variants, however, modulates the cell surface expression-levels and subsequent functional responses of the 7TM H3R isoforms. Coexpression of the rH3AR and the rH3D isoforms resulted in the intracellular retention of the rH3AR and reduced rH3AR functionality. Finally, we show that in rat brain, the H3R mRNA expression levels are modulated upon treatment with the convulsant pentylenetetrazole, suggesting that the rH3R isoforms described herein thus represent a novel physiological mechanism for controlling the activity of the histaminergic system. PMID:16415177

  10. Differential expression of Na+, K(+)-ATPase α-1 isoforms during seawater acclimation in the amphidromous galaxiid fish Galaxias maculatus.

    Science.gov (United States)

    Urbina, Mauricio A; Schulte, Patricia M; Bystriansky, Jason S; Glover, Chris N

    2013-04-01

    Inanga (Galaxias maculatus) is an amphidromous fish with a well-known capacity to withstand a wide range of environmental salinities. To investigate the molecular mechanisms facilitating acclimation of inanga to seawater, several isoforms of the Na(+), K(+)-ATPase ion transporter were identified. This included three α-1 (a, b and c), an α-2 and two α-3 (a and b) isoforms. Phylogenetic analysis showed that the inanga α-1a and α-1b formed a clade with the α-1a and α-1b isoforms of rainbow trout, while another clade contained the α-1c isoforms of these species. The expression of all the α-1 isoforms was modulated after seawater exposure (28‰). In gills, the expression of the α-1a isoform was progressively down-regulated after seawater exposure, while the expression of the α-1b isoform was up-regulated. The α-1c isoform behaved similarly to the α-1a, although changes were less dramatic. Physiological indicators of salinity acclimation matched the time frame of the changes observed at the molecular level. A 24-h osmotic shock period was highlighted by small increases in plasma osmolality, plasma Na(+) and a decrease in muscle tissue water content. Thereafter, these values returned close to their pre-exposure (freshwater) values. Na(+), K(+)-ATPase activity showed a decreasing trend over the first 72 h following seawater exposure, but activity increased after 240 h. Our results indicate that inanga is an excellent osmoregulator, an ability that is conferred by the rapid activation of physiological and molecular responses to salinity change. PMID:23142926

  11. Activity of the acyl-CoA synthetase ACSL6 isoforms: role of the fatty acid Gate-domains

    Directory of Open Access Journals (Sweden)

    Siliakus Melvin

    2010-04-01

    Full Text Available Abstract Background Activation of fatty acids by acyl-CoA synthetase enzymes is required for de novo lipid synthesis, fatty acid catabolism, and remodeling of biological membranes. Human long-chain acyl-CoA synthetase member 6, ASCL6, is a form present in the plasma membrane of cells. Splicing events affecting the amino-terminus and alternative motifs near the ATP-binding site generate different isoforms of ACSL6. Results Isoforms with different fatty acid Gate-domain motifs have different activity and the form lacking this domain, isoform 3, showed no detectable activity. Enzymes truncated of the first 40 residues generate acyl-CoAs at a faster rate than the full-length protein. The gating residue, which prevents entry of the fatty acid substrate unless one molecule of ATP has already accessed the catalytic site, was identified as a tyrosine for isoform 1 and a phenylalanine for isoform 2 at position 319. All isoforms, with or without a fatty acid Gate-domain, as well as recombinant protein truncated of the N-terminus, can interact to form enzymatic complexes with identical or different isoforms. Conclusion The alternative fatty acid Gate-domain motifs are essential determinants for the activity of the human ACSL6 isoforms, which appear to act as homodimeric enzyme as well as in complex with other spliced forms. These findings provide evidence that the diversity of these enzyme species could produce the variety of acyl-CoA synthetase activities that are necessary to generate and repair the hundreds of lipid species present in membranes.

  12. Integrated genomic and functional analyses of histone demethylases identify oncogenic KDM2A isoform in breast cancer.

    Science.gov (United States)

    Liu, Hui; Liu, Lanxin; Holowatyj, Andreana; Jiang, Yuanyuan; Yang, Zeng-Quan

    2016-05-01

    Histone lysine demethylases (KDMs) comprise a large class of enzymes that catalyze site-specific demethylation of lysine residues on histones and other proteins. They play critical roles in controlling transcription, chromatin architecture, and cellular differentiation. However, the genomic landscape and clinical significance of KDMs in breast cancer remain poorly characterized. Here, we conducted a meta-analysis of 24 KDMs in breast cancer and identified associations among recurrent copy number alterations, gene expression, breast cancer subtypes, and clinical outcome. Two KDMs, KDM2A and KDM5B, had the highest frequency of genetic amplification and overexpression. Furthermore, among the 24 KDM genes, KDM2A had the highest correlation between copy number and mRNA expression, and high mRNA levels of KDM2A were significantly associated with shorter survival of breast cancer patients. KDM2A has two isoforms: the long isoform is comprised of a JmjC domain, CXXC-zinc finger, PHD zinc finger, F-box, and the AMN1 protein domain; whereas the short isoform of KDM2A lacks the N-terminal JmjC domain but contains all other motifs. Detailed characterization of KDM2A in breast cancer revealed that the short isoform of KDM2A is more abundant than the long isoform at DNA, mRNA, and protein levels in a subset of breast cancers. Furthermore, our data indicate that the short isoform of KDM2A has oncogenic potential and functions as an oncogenic isoform in a subset of breast cancers. Taken together, our findings suggest that amplification and overexpression of the KDM2A short isoform is critical in breast cancer progression. © 2015 Wiley Periodicals, Inc. PMID:26207617

  13. Evaluation of Hepcidin Isoforms in Hemodialysis Patients by a Proteomic Approach Based on SELDI-TOF MS

    OpenAIRE

    Oliviero Olivieri; Antonio Lupo; Nicola Martinelli; Albino Poli; Nicola Tessitore; Valeria Bedogna; Annalisa Castagna; Federica Zaninotto; Domenico Girelli; Natascia Campostrini

    2010-01-01

    The hepatic iron regulator hormone hepcidin consists, in its mature form, of 25 amino acids, but two other isoforms, hepcidin-20 and hepcidin-22, have been reported, whose biological meaning remains poorly understood. We evaluated hepcidin isoforms in sera from 57 control and 54 chronic haemodialysis patients using a quantitative proteomic approach based on SELDI-TOF-MS. Patients had elevated serum levels of both hepcidin-25 and hepcidin-20 as compared to controls (geometric means: 7.52 versu...

  14. Differential expression of intracellular and secreted osteopontin isoforms by murine macrophages in response to Toll-like receptor agonists.

    OpenAIRE

    Zhao, Wei; Wang, Lijuan; Zhang, Lei; Yuan, Chao; Kuo, Paul C.; Gao, Chengjiang

    2015-01-01

    Osteopontin (OPN), expressed by various immune cells, modulates both innate and adaptive immune responses. Different immune cells have shown differential expression of the two isoforms of OPN: secreted form of OPN (sOPN) and intracellular form of OPN (iOPN). However, the molecular mechanisms that control opn gene expression and the OPN isoforms produced by immune cells remain largely unknown. In this study, we demonstrate that OPN mRNA and protein expression are significantly up-regulated upo...

  15. In Vitro Inhibitory Activities of the Extract of Hibiscus Sabdariffa L. (Family Malvaceae) on Selected Cytochrome P450 Isoforms

    OpenAIRE

    Johnson, Showande Segun; Oyelola, Fakeye Titilayo; Ari, Tolonen; Juho, Hokkanen

    2013-01-01

    Literature is scanty on the interaction potential of Hibiscus sabdariffa L., plant extract with other drugs and the affected targets. This study was conducted to investigate the cytochrome P450 (CYP) isoforms that are inhibited by the extract of Hibiscus sabdariffa L. in vitro. The inhibition towards the major drug metabolizing CYP isoforms by the plant extract were estimated in human liver microsomal incubations, by monitoring the CYP-specific model reactions through previously validated N-i...

  16. Influence of Temperature, Hypercapnia, and Development on the Relative Expression of Different Hemocyanin Isoforms in the Common Cuttlefish Sepia officinalis

    OpenAIRE

    Strobel, Anneli; Hu, Marian Y.A.; Gutowska, Magdalena A.; Lieb, Bernhard; Lucassen, Magnus; Melzner, Frank; Pörtner, Hans-Otto; Mark, Felix Christopher

    2012-01-01

    The cuttlefish Sepia officinalis expresses several hemocyanin isoforms with potentially different pH optima, indicating their reliance on efficient pH regulation in the blood. Ongoing ocean warming and acidification could influence the oxygen-binding properties of respiratory pigments in ectothermic marine invertebrates. This study examined whether S. officinalis differentially expresses individual hemocyanin isoforms to maintain optimal oxygen transport during development and ...

  17. Two Regions of the Tail Are Necessary for the Isoform-specific Functions of Nonmuscle Myosin IIB

    OpenAIRE

    Sato, Masaaki K.; Takahashi, Masayuki; Yazawa, Michio

    2007-01-01

    To function in the cell, nonmuscle myosin II molecules assemble into filaments through their C-terminal tails. Because myosin II isoforms most likely assemble into homo-filaments in vivo, it seems that some self-recognition mechanisms of individual myosin II isoforms should exist. Exogenous expression of myosin IIB rod fragment is thus expected to prevent the function of myosin IIB specifically. We expected to reveal some self-recognition sites of myosin IIB from the phenotype by expressing a...

  18. Centrosomin: A Complex Mix of Long and Short Isoforms Is Required for Centrosome Function During Early Development in Drosophila melanogaster

    OpenAIRE

    Eisman, Robert C.; Phelps, Melissa A. S.; Kaufman, Thomas C.

    2009-01-01

    Centrosomin (Cnn) is a required core component in mitotic centrosomes during syncytial development and the presence of Cnn at centrosomes has become synonymous with fully functional centrosomes in Drosophila melanogaster. Previous studies of Cnn have attributed this embryonic function to a single isoform or splice variant. In this study, we present new evidence that significantly increases the complexity of cnn. Rather than a single isoform, Cnn function can be attributed to two unique classe...

  19. Identification of T-cell factor-4 isoforms that contribute to the malignant phenotype of hepatocellular carcinoma cells

    International Nuclear Information System (INIS)

    The Wnt/β-catenin signaling pathway is frequently activated in hepatocellular carcinoma (HCC). Downstream signaling events involving the Wnt/β-catenin cascade occur through T-cell factor (TCF) proteins. The human TCF-4 gene is composed of 17 exons with multiple alternative splicing sites. However, the role of different TCF-4 isoforms in the pathogenesis of HCC is unknown. The purpose of this study was to identify and characterize TCF-4 isoforms in HCC. We identified 14 novel TCF-4 isoforms from four HCC cell lines. Functional analysis following transfection and expression in HCC cells revealed distinct effects on the phenotype. The TCF-4J isoform expression produced striking features of malignant transformation characterized by high cell proliferation rate, migration and colony formation even though its transcriptional activity was low. In contrast, the TCF-4K isoform displayed low TCF transcriptional activity; cell proliferation rate and colony formation were reduced as well. Interestingly, TCF-4J and TCF-4K differed by only five amino acids (the SxxSS motif). Thus, these studies suggest that conserved splicing motifs may have a major influence on the transcriptional activity and functional properties of TCF-4 isoforms and alter the characteristics of the malignant phenotype.

  20. Immunocytochemical studies of the distribution of alpha and pi isoforms of glutathione S-transferase in cystic renal diseases.

    Science.gov (United States)

    Hiley, C G; Otter, M; Bell, J; Strange, R C; Keeling, J W

    1994-01-01

    We describe immunohistochemical studies of the expression of alpha and pi class glutathione S-transferases (GSTs) in normal fetal kidneys. These define, in greater detail, changes in expression of alpha isoforms in the proximal tubule. At about 36 weeks of gestation expression of alpha isoforms was down-regulated in the distal tubules and collecting ducts while pi was expressed throughout the nephron. Tubular expression of alpha isoforms was restricted to the part adjacent to the glomerulus; cells farthest from the glomerulus were negative. After 40 weeks of gestation, alpha isoforms were expressed along the entire proximal tubule, while pi was restricted to the distal tubule and collecting ducts. GST expression was also studied in multicystic renal dysplasia, autosomal recessive polycystic kidney disease, and autosomal dominant polycystic kidney disease to determine whether the patterns of expression of alpha and pi isoforms allow identification of the origin of the cysts that characterize these diseases. Cysts were lined by epithelia that were strongly positive for alpha and pi isoforms. The epithelia of noncystic nephrons in renal cystic dysplasia demonstrated delayed maturity, suggesting that GST expression was dependent on the stage of development and not length of gestation. PMID:8066005

  1. Interaction of meropenem with 'N' and 'B' isoforms of human serum albumin: a spectroscopic and molecular docking study.

    Science.gov (United States)

    Rehman, Md Tabish; Ahmed, Sarfraz; Khan, Asad U

    2016-09-01

    Carbapenems are used to control the outbreak of β-lactamases expressing bacteria. The effectiveness of drugs is influenced by its interaction with human serum albumin (HSA). Strong binding of carbapenems to HSA may lead to decreased bioavailability of the drug. The non-optimal drug dosage will provide a positive selection pressure on bacteria to develop resistance. Here, we investigated the interaction between meropenem and HSA at physiological pH 7.5 (N-isoform HSA) and non-physiological pH 9.2 (B-isoform HSA). Results showed that meropenem quenches the fluorescence of both 'N' and 'B' isoforms of HSA (ΔG < 0 and binding constant ~10(4) M(-1)). Electrostatic interactions and van der Waal interactions along with H-bonds stabilized the complex of meropenem with 'N' and 'B' isoforms of HSA, respectively. Molecular docking results revealed that meropenem binds to HSA near Sudlow's site II (subdomain IIIA) close to Trp-214 with a contribution of a few residues of subdomain IIA. CD spectroscopy showed a change in the conformation of both the isoforms of HSA upon meropenem binding. The catalytic efficiency of HSA (only N-isoform) on p-nitrophenyl acetate was increased primarily due to a decrease in Km and an increase in kcat values. This study provides an insight into the molecular basis of interaction between meropenem and HSA. PMID:26372227

  2. Identification of T-cell factor-4 isoforms that contribute to the malignant phenotype of hepatocellular carcinoma cells

    Energy Technology Data Exchange (ETDEWEB)

    Tsedensodnom, Orkhontuya [Liver Research Center, Rhode Island Hospital and The Warren Alpert Medical School of Brown University, Providence, RI (United States); Department of Molecular Biology Cell Biology and Biochemistry, The Warren Alpert Medical School of Brown University, Providence, RI (United States); Koga, Hironori; Rosenberg, Stephen A.; Nambotin, Sarah B.; Carroll, John J.; Wands, Jack R. [Liver Research Center, Rhode Island Hospital and The Warren Alpert Medical School of Brown University, Providence, RI (United States); Kim, Miran, E-mail: Miran_Kim@brown.edu [Liver Research Center, Rhode Island Hospital and The Warren Alpert Medical School of Brown University, Providence, RI (United States)

    2011-04-15

    The Wnt/{beta}-catenin signaling pathway is frequently activated in hepatocellular carcinoma (HCC). Downstream signaling events involving the Wnt/{beta}-catenin cascade occur through T-cell factor (TCF) proteins. The human TCF-4 gene is composed of 17 exons with multiple alternative splicing sites. However, the role of different TCF-4 isoforms in the pathogenesis of HCC is unknown. The purpose of this study was to identify and characterize TCF-4 isoforms in HCC. We identified 14 novel TCF-4 isoforms from four HCC cell lines. Functional analysis following transfection and expression in HCC cells revealed distinct effects on the phenotype. The TCF-4J isoform expression produced striking features of malignant transformation characterized by high cell proliferation rate, migration and colony formation even though its transcriptional activity was low. In contrast, the TCF-4K isoform displayed low TCF transcriptional activity; cell proliferation rate and colony formation were reduced as well. Interestingly, TCF-4J and TCF-4K differed by only five amino acids (the SxxSS motif). Thus, these studies suggest that conserved splicing motifs may have a major influence on the transcriptional activity and functional properties of TCF-4 isoforms and alter the characteristics of the malignant phenotype.

  3. Purification and characterization of soluble (cytosolic) and bound (cell wall) isoforms of invertases in barley (Hordeum vulgare) elongating stem tissue

    Science.gov (United States)

    Karuppiah, N.; Vadlamudi, B.; Kaufman, P. B.

    1989-01-01

    Three different isoforms of invertases have been detected in the developing internodes of barley (Hordeum vulgare). Based on substrate specificities, the isoforms have been identified to be invertases (beta-fructosidases EC 3.2.1.26). The soluble (cytosolic) invertase isoform can be purified to apparent homogeneity by diethylaminoethyl cellulose, Concanavalin-A Sepharose, organo-mercurial Sepharose, and Sephacryl S-300 chromatography. A bound (cell wall) invertase isoform can be released by 1 molar salt and purified further by the same procedures as above except omitting the organo-mercurial Sepharose affinity chromatography step. A third isoform of invertase, which is apparently tightly associated with the cell wall, cannot be isolated yet. The soluble and bound invertase isoforms were purified by factors of 60- and 7-fold, respectively. The native enzymes have an apparent molecular weight of 120 kilodaltons as estimated by gel filtration. They have been identified to be dimers under denaturing and nondenaturing conditions. The soluble enzyme has a pH optimum of 5.5, Km of 12 millimolar, and a Vmax of 80 micromole per minute per milligram of protein compared with cell wall isozyme which has a pH optimum of 4.5, Km of millimolar, and a Vmax of 9 micromole per minute per milligram of protein.

  4. Expression of tropomyosin 2 gene isoforms in human breast cancer cell lines

    Science.gov (United States)

    DUBE, SYAMALIMA; THOMAS, ANISH; ABBOTT, LYNN; BENZ, PATRICIA; MITSCHOW, CHARLES; DUBE, DIPAK K.; POIESZ, BERNARD J.

    2016-01-01

    In humans, four tropomyosin genes (TPM1, TPM2, TPM3, and TPM4) are known to produce a multitude of isoforms via alternate splicing and/or using alternate promoters. Expression of tropomyosin has been shown to be modulated at both the transcription and the translational levels. Tropomyosins are known to make up some of the stress fibers of human epithelial cells and differences in their expression has been demonstrated in malignant breast epithelial cell lines compared to 'normal' breast cell lines. We have recently reported the expression of four novel TPM1 isoforms (TPM1λ, TPM1µ, TPM1ν, and TPM1ξ) from human malignant tumor breast cell lines that are not expressed in adult and fetal cardiac tissue. Also, we evaluated their expression in relation to the stress fiber formation. In this study, nine malignant breast epithelial cell lines and three 'normal' breast cell lines were examined for stress fiber formation and expression of tropomyosin 2 (TPM2) isoform-specific RNAs and proteins. Stress fiber formation was assessed by immunofluorescence using Leica AF6000 Deconvolution microscope. Stress fiber formation was strong (++++) in the 'normal' cell lines and varied among the malignant cell lines (negative to +++). No new TPM2 gene RNA isoforms were identified, and TPM2β was the most frequently expressed TPM2 RNA and protein isoform. Stress fiber formation positively correlated with TPM2β RNA or protein expression at high, statistically significant degrees. Previously, we had shown that TPM1δ and TPM1λ positively and inversely, respectively, correlated with stress fiber formation. The most powerful predictor of stress fiber formation was the combination of TPM2β RNA, TPM1δ RNA, and the inverse of TPM1λ RNA expression. Our results suggest that the increased expression of TPM1λ and the decreased expression of TPM1δ RNA and TPM2β may lead to decreased stress fiber formation and malignant transformation in human breast epithelial cells. PMID:27108600

  5. Immunopositivity for histone macroH2A1 isoforms marks steatosis-associated hepatocellular carcinoma.

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    Francesca Rappa

    Full Text Available BACKGROUND: Hepatocellular carcinoma (HCC is one of the most common cancers worldwide. Prevention and risk reduction are important and the identification of specific biomarkers for early diagnosis of HCC represents an active field of research. Increasing evidence indicates that fat accumulation in the liver, defined as hepatosteatosis, is an independent and strong risk factor for developing an HCC. MacroH2A1, a histone protein generally associated with the repressed regions of chromosomes, is involved in hepatic lipid metabolism and is present in two alternative spliced isoforms, macroH2A1.1 and macroH2A1.2. These isoforms have been shown to predict lung and colon cancer recurrence but to our knowledge, their role in fatty-liver associated HCC has not been investigated previously. METHODS: We examined macroH2A1.1 and macroH2A1.2 protein expression levels in the liver of two murine models of fat-associated HCC, the high fat diet/diethylnistrosamine (DEN and the phosphatase and tensin homolog (PTEN liver specific knock-out (KO mouse, and in human liver samples of subjects with steatosis or HCC, using immunoblotting and immunohistochemistry. RESULTS: Protein levels for both macroH2A1 isoforms were massively upregulated in HCC, whereas macroH2A1.2 was specifically upregulated in steatosis. In addition, examination of human liver samples showed a significant difference (p<0.01 in number of positive nuclei in HCC (100% of tumor cells positive for either macroH2A1.1 or macroH2A1.2, when compared to steatosis (<2% of hepatocytes positive for either isoform. The steatotic areas flanking the tumors were highly immunopositive for macroH2A1.1 and macroH2A1.2. CONCLUSIONS: These data obtained in mice and humans suggest that both macroH2A1 isoforms may play a role in HCC pathogenesis and moreover may be considered as novel diagnostic markers for human HCC.

  6. CD44 isoforms are heterogeneously expressed in breast cancer and correlate with tumor subtypes and cancer stem cell markers

    International Nuclear Information System (INIS)

    The CD44 cell adhesion molecule is aberrantly expressed in many breast tumors and has been implicated in the metastatic process as well as in the putative cancer stem cell (CSC) compartment. We aimed to investigate potential associations between alternatively spliced isoforms of CD44 and CSCs as well as to various breast cancer biomarkers and molecular subtypes. We used q-RT-PCR and exon-exon spanning assays to analyze the expression of four alternatively spliced CD44 isoforms as well as the total expression of CD44 in 187 breast tumors and 13 cell lines. ALDH1 protein expression was determined by IHC on TMA. Breast cancer cell lines showed a heterogeneous expression pattern of the CD44 isoforms, which shifted considerably when cells were grown as mammospheres. Tumors characterized as positive for the CD44+/CD24- phenotype by immunohistochemistry were associated to all isoforms except the CD44 standard (CD44S) isoform, which lacks all variant exons. Conversely, tumors with strong expression of the CSC marker ALDH1 had elevated expression of CD44S. A high expression of the CD44v2-v10 isoform, which retain all variant exons, was correlated to positive steroid receptor status, low proliferation and luminal A subtype. The CD44v3-v10 isoform showed similar correlations, while high expression of CD44v8-v10 was correlated to positive EGFR, negative/low HER2 status and basal-like subtype. High expression of CD44S was associated with strong HER2 staining and also a subgroup of basal-like tumors. Unsupervised hierarchical cluster analysis of CD44 isoform expression data divided tumors into four main clusters, which showed significant correlations to molecular subtypes and differences in 10-year overall survival. We demonstrate that individual CD44 isoforms can be associated to different breast cancer subtypes and clinical markers such as HER2, ER and PgR, which suggests involvement of CD44 splice variants in specific oncogenic signaling pathways. Efforts to link CD44 to CSCs

  7. ADAPTIVE CHANGES OF MYOSIN ISOFORMS IN RESPONSE TO LONG-TERM STRENGTH AND POWER TRAINING IN MIDDLE-AGED MEN

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    Raivo Puhke

    2006-06-01

    Full Text Available The purpose of the study was to examine the adaptive changes in myosin heavy chain (MHC and light chain (MLC isoforms in human vastus lateralis muscle caused by long-term strength and power training (54 weeks, approximately 3 times a week in untrained middle- aged men (16 in the training and 6 in the control group. Muscular MHC and MLC isoforms were determined by means of SDS-PAGE gel electrophoresis. During the training period, maximal anaerobic cycling power increased by 64 W (p < 0.001 and the maximal jumping height by 1.5 cm (p < 0. 05 in the training group, but no significant changes were found in the control group. However, the group by time effect was not significant. In the training group, the increase of the maximal jumping height correlated with the number of strength and power training sessions (r = 0.56; p < 0.05. The change of the proportion of MHC IIa isoform from 52.6 ± 12.2% to 59.4 ± 11.6% did not reach statistical significance (p = 0.070 for group by time; within training group p = 0.061 and neither did the change of the proportion of MHC IIx isoform from 18.1 ± 11.4% to 11.1 ± 9.1% (p = 0.104 for group by time; within training group p=0.032. The degree of change of MHC IIx isoform correlated with the amount of earlier recreational sports activity (r = 0.61; p < 0.05. In the training group, the changes of MLC1s isoform correlated negatively with the changes of MLC1f isoform (r = -0. 79; p < 0.05 as well as with the changes in maximal anaerobic cycling power (r = -0.81; p < 0.05, and positively with those of MHC I isoform (r = 0.81; p < 0.05. In conclusion, the long- term strength and power training ~3 times a week seemed to have only slight effects on fast MHC isoforms in the vastus lateralis muscle of untrained middle-aged men; the proportion of MHC IIa tended to increase and that of MHC IIx tended to decrease. No changes in MLC isoform profile could be shown

  8. Retinal and choroidal TGF-beta in the tree shrew model of myopia: isoform expression, activation and effects on function.

    Science.gov (United States)

    Jobling, Andrew Ian; Wan, Ran; Gentle, Alex; Bui, Bang Viet; McBrien, Neville Anthony

    2009-03-01

    A visually evoked signalling cascade, which begins in the retina, transverses the choroid, and mediates scleral remodelling, is considered to control eye growth. The ubiquitous cytokine TGF-beta has been associated with alterations in ocular growth, where alterations in scleral TGF-beta isoforms mediate the scleral remodelling that results in myopia. However, while the TGF-beta isoforms have been implicated in the scleral change during myopia development, it is unclear whether alterations in retinal and choroidal isoforms constitute part of the retinoscleral cascade. This study characterised the retinal and choroidal TGF-beta isoform profiles and TGF-beta2 activation during different stages of myopia development, as induced by form deprivation, in a mammalian model of eye growth. Using quantitative real-time PCR, the mRNA for all three mammalian isoforms of TGF-beta was detected in tree shrew retina and choroid. Distinct tissue-specific isoform profiles were observed for the retina (TGF-beta1:TGF-beta2:TGF-beta3=20:2085:1) and choroid (TGF-beta1:TGF-beta2:TGF-beta3=16:23:1), which remained constant over the development period under investigation. The active and latent pools of retinal TGF-beta2 were quantified using ELISA with the majority (>94%) of total TGF-beta2 found in the latent form. Unlike previous scleral data showing early and continuous decreases in TGF-beta isoform expression during myopia development, the levels of the three isoforms remained within normal ranges for retinal (TGF-beta1, -14 to +14%; TGF-beta2, -2 to +20%; TGF-beta3, -10 to +26%) and choroidal (TGF-beta1, -19 to +21%; TGF-beta2, -26 to +8%; TGF-beta3, -11 to +28%) tissues during myopia development (induction times of 3h, 7h, 11h, 24h, and 5 days). A 40% decrease in retinal TGF-beta2 activation was observed after 5 days of myopia development, however, there was no functional correlate of altered TGF-beta2 activity, as assessed by the retinal ERG response. Overall, these data highlight

  9. First Trimester Pregnancy Loss and the Expression of alternatively spliced NKp30 isoforms in Maternal Blood and Placental Tissue

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    Avishai eShemesh

    2015-06-01

    Full Text Available In this study, we aimed to investigate whether first trimester pregnancy loss is associated with differences in expression of NKp30 splice variants (isoforms in maternal peripheral blood or placental tissue. We conducted a prospective case-control study; a total of 33 women undergoing dilation and curettage due to first trimester pregnancy loss were further subdivided into groups with sporadic or recurrent pregnancy loss. The control group was comprised of women undergoing elective termination of pregnancy. The qPCR approach was employed to assess the relative expression of NKp30 isoforms as well as the total expression of NKp30 and NKp46 receptors between the selected groups. Results show that in both PBMC and placental tissue, NKp46 and NKp30 expression was mildly elevated in the pregnancy loss groups compared with the elective group. In particular, NKp46 elevation was significant. Moreover, expression analysis of NKp30 isoforms manifested a different profile between PBMC and the placenta. NKp30-a and NKp30-b isoforms in the placental tissue, but not in PBMC, showed a significant increase in the pregnancy loss groups compared with the elective group. Placental expression of NKp30 activating isoforms -a and -b in the pregnancy loss groups was negatively correlated with PLGF expression. In contrast, placental expression of these isoforms in the elective group was positively correlated with TNFα, IL-10 and VEGF-A expression. The altered expression of NKp30 activating isoforms in placental tissue from patients with pregnancy loss compared to the elective group and the different correlations with cytokine expression point to the involvement of NKp30-mediated function in pregnancy loss.

  10. Herpes simplex virus 1 ubiquitin ligase ICP0 interacts with PML isoform I and induces its SUMO-independent degradation.

    Science.gov (United States)

    Cuchet-Lourenço, Delphine; Vanni, Emilia; Glass, Mandy; Orr, Anne; Everett, Roger D

    2012-10-01

    Herpes simplex virus 1 (HSV-1) immediate-early protein ICP0 localizes to cellular structures known as promyelocytic leukemia protein (PML) nuclear bodies or ND10 and disrupts their integrity by inducing the degradation of PML. There are six PML isoforms with different C-terminal regions in ND10, of which PML isoform I (PML.I) is the most abundant. Depletion of all PML isoforms increases the plaque formation efficiency of ICP0-null mutant HSV-1, and reconstitution of expression of PML.I and PML.II partially reverses this improved replication. ICP0 also induces widespread degradation of SUMO-conjugated proteins during HSV-1 infection, and this activity is linked to its ability to counteract cellular intrinsic antiviral resistance. All PML isoforms are highly SUMO modified, and all such modified forms are sensitive to ICP0-mediated degradation. However, in contrast to the situation with the other isoforms, ICP0 also targets PML.I that is not modified by SUMO, and PML in general is degraded more rapidly than the bulk of other SUMO-modified proteins. We report here that ICP0 interacts with PML.I in both yeast two-hybrid and coimmunoprecipitation assays. This interaction is dependent on PML.I isoform-specific sequences and the N-terminal half of ICP0 and is required for SUMO-modification-independent degradation of PML.I by ICP0. Degradation of the other PML isoforms by ICP0 was less efficient in cells specifically depleted of PML.I. Therefore, ICP0 has two distinct mechanisms of targeting PML: one dependent on SUMO modification and the other via SUMO-independent interaction with PML.I. We conclude that the ICP0-PML.I interaction reflects a countermeasure to PML-related antiviral restriction. PMID:22875967

  11. Differential induction of FosB isoforms throughout the brain by fluoxetine and chronic stress.

    Science.gov (United States)

    Vialou, Vincent; Thibault, Mackenzie; Kaska, Sophia; Cooper, Sarah; Gajewski, Paula; Eagle, Andrew; Mazei-Robison, Michelle; Nestler, Eric J; Robison, A J

    2015-12-01

    Major depressive disorder is thought to arise in part from dysfunction of the brain's "reward circuitry", consisting of the mesolimbic dopamine system and the glutamatergic and neuromodulatory inputs onto this system. Both chronic stress and antidepressant treatment regulate gene transcription in many of the brain regions that make up these circuits, but the exact nature of the transcription factors and target genes involved in these processes remain unclear. Here, we demonstrate induction of the FosB family of transcription factors in ∼25 distinct regions of adult mouse brain, including many parts of the reward circuitry, by chronic exposure to the antidepressant fluoxetine. We further uncover specific patterns of FosB gene product expression (i.e., differential expression of full-length FosB, ΔFosB, and Δ2ΔFosB) in brain regions associated with depression--the nucleus accumbens (NAc), prefrontal cortex (PFC), and hippocampus--in response to chronic fluoxetine treatment, and contrast these patterns with differential induction of FosB isoforms in the chronic social defeat stress model of depression with and without fluoxetine treatment. We find that chronic fluoxetine, in contrast to stress, causes induction of the unstable full-length FosB isoform in the NAc, PFC, and hippocampus even 24 h following the final injection, indicating that these brain regions may undergo chronic activation when fluoxetine is on board, even in the absence of stress. We also find that only the stable ΔFosB isoform correlates with behavioral responses to stress. These data suggest that NAc, PFC, and hippocampus may present useful targets for directed intervention in mood disorders (ie, brain stimulation or gene therapy), and that determining the gene targets of FosB-mediated transcription in these brain regions in response to fluoxetine may yield novel inroads for pharmaceutical intervention in depressive disorders. PMID:26164345

  12. A novel alternatively spliced isoform of the mu-opioid receptor: functional antagonism

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    Wentworth Sean

    2010-06-01

    Full Text Available Abstract Background Opioids are the most widely used analgesics for the treatment of clinical pain. They produce their therapeutic effects by binding to μ-opioid receptors (MORs, which are 7 transmembrane domain (7TM G-protein-coupled receptors (GPCRs, and inhibiting cellular activity. However, the analgesic efficacy of opioids is compromised by side-effects such as analgesic tolerance, dependence and opioid-induced hyperalgesia (OIH. In contrast to opioid analgesia these side effects are associated with cellular excitation. Several hypotheses have been advanced to explain these phenomena, yet the molecular mechanisms underlying tolerance and OIH remain poorly understood. Results We recently discovered a new human alternatively spliced isoform of MOR (MOR1K that is missing the N-terminal extracellular and first transmembrane domains, resulting in a 6TM GPCR variant. To characterize the pattern of cellular transduction pathways activated by this human MOR1K isoform, we conducted a series of pharmacological and molecular experiments. Results show that stimulation of MOR1K with morphine leads to excitatory cellular effects. In contrast to stimulation of MOR1, stimulation of MOR1K leads to increased Ca2+ levels as well as increased nitric oxide (NO release. Immunoprecipitation experiments further reveal that unlike MOR1, which couples to the inhibitory Gαi/o complex, MOR1K couples to the stimulatory Gαs complex. Conclusion The major MOR1 and the alternative MOR1K isoforms mediate opposite cellular effects in response to morphine, with MOR1K driving excitatory processes. These findings warrant further investigations that examine animal and human MORK1 expression and function following chronic exposure to opioids, which may identify MOR1K as a novel target for the development of new clinically effective classes of opioids that have high analgesic efficacy with diminished ability to produce tolerance, OIH, and other unwanted side-effects.

  13. Screening for Fabry Disease by Urinary Globotriaosylceramide Isoforms Measurement in Patients with Left Ventricular Hypertrophy

    Science.gov (United States)

    Gaggl, Martina; Lajic, Natalija; Heinze, Georg; Voigtländer, Till; Sunder-Plassmann, Raute; Paschke, Eduard; Fauler, Günter; Sunder-Plassmann, Gere; Mundigler, Gerald

    2016-01-01

    Background: Left ventricular hypertrophy (LVH) is a frequent echocardiographic feature in Fabry disease (FD) and in severe cases may be confused with hypertrophic cardiomyopathy (HCM) of other origin. The prevalence of FD in patients primarily diagnosed with HCM varies considerably in screening and case finding studies, respectively. In a significant proportion of patients, presenting with only mild or moderate LVH and unspecific clinical signs FD may remain undiagnosed. Urinary Gb3 isoforms have been shown to detect FD in both, women and men. We examined whether this non-invasive method would help to identify new FD cases in a non-selected cohort of patients with various degree of LVH. Methods and results: Consecutive patients older than 18 years with a diastolic interventricular septal wall thickness of ≥12mm determined by echocardiography were included. Referral diagnosis was documented and spot urine was collected. Gb3 was measured by mass spectroscopy. Subjects with an elevated Gb3-24:18 ratio were clinically examined for signs of FD, α-galactosidase-A activity in leukocytes was determined and GLA-mutation-analysis was performed. We examined 2596 patients. In 99 subjects urinary Gb3 isoforms excretion were elevated. In these patients no new cases of FD were identified by extended FD assessment. In two of three patients formerly diagnosed with FD Gb3-24:18 ratio was elevated and would have led to further diagnostic evaluation. Conclusion: Measurement of urinary Gb3 isoforms in a non-selected cohort with LVH was unable to identify new cases of FD. False positive results may be prevented by more restricted inclusion criteria and may improve diagnostic accuracy of this method.

  14. Subunit-specific sulphation of oligosaccharides relating to charge-heterogeneity in porcine lutrophin isoforms.

    Science.gov (United States)

    Ujihara, M; Yamamoto, K; Nomura, K; Toyoshima, S; Demura, H; Nakamura, Y; Ohmura, K; Osawa, T

    1992-06-01

    Lutrophin (LH) consists of an array of isoforms with different charges and bioactivities. This study was undertaken to clarify specifically how oligosaccharides of alpha and beta subunits contribute to LH isoform charges. Porcine LH (pLH) was separated into four isoforms by isoelectric focusing (IEF), followed by subunit isolation. Their oligosaccharides were released by hydrazinolysis, labelled by reduction with NaB3H4, and fractionated by HPLC with a Mono Q column into five populations differing in the number of sulphate (S) and sialic acid (N) residues, designated as Neutral, N-1, S-1, S-N and S-2. Oligosaccharides were predominantly sulphated (S-1 and S-2) and infrequently sialylated (N-1 and S-N). Further analysis, including concanavalin A (Con A) affinity chromatography, desialylation, desulphation, sequential exoglycosidase digestion and methylation, clarified the structures of the acidic oligosaccharides. All were of the biantennary complex type. Their two peripheral branches were SO4-4GalNAc beta 1-4Glc-NAc and GalNAc beta 1-4GlcNAc or GlcNAc in S-1, SO4-4GalNAc beta 1-4GlcNAc and Sia alpha 2-6Gal beta 1-4GlcNAc in S-N, and (SO4-4GalNAc beta 1-4GlcNAc)2 in S-2 (where GalNAc is N-acetylgalactosamine and GlcNAc is N-acetylglucosamine). Ten percent of S-1 and of S-N had a bisecting GlcNAc residue. Sulphate residues occurred in nearly the same amount for both subunits; however, the alpha and beta subunits were sulphated differently. S-1 predominated in the alpha subunit, while S-1 and S-2 were major components in the beta subunit.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1498420

  15. Computational identification of transcriptionally co-regulated genes, validation with the four ANT isoform genes

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    Dupont Pierre-Yves

    2012-09-01

    Full Text Available Abstract Background The analysis of gene promoters is essential to understand the mechanisms of transcriptional regulation required under the effects of physiological processes, nutritional intake or pathologies. In higher eukaryotes, transcriptional regulation implies the recruitment of a set of regulatory proteins that bind on combinations of nucleotide motifs. We developed a computational analysis of promoter nucleotide sequences, to identify co-regulated genes by combining several programs that allowed us to build regulatory models and perform a crossed analysis on several databases. This strategy was tested on a set of four human genes encoding isoforms 1 to 4 of the mitochondrial ADP/ATP carrier ANT. Each isoform has a specific tissue expression profile linked to its role in cellular bioenergetics. Results From their promoter sequence and from the phylogenetic evolution of these ANT genes in mammals, we constructed combinations of specific regulatory elements. These models were screened using the full human genome and databases of promoter sequences from human and several other mammalian species. For each of transcriptionally regulated ANT1, 2 and 4 genes, a set of co-regulated genes was identified and their over-expression was verified in microarray databases. Conclusions Most of the identified genes encode proteins with a cellular function and specificity in agreement with those of the corresponding ANT isoform. Our in silico study shows that the tissue specific gene expression is mainly driven by promoter regulatory sequences located up to about a thousand base pairs upstream the transcription start site. Moreover, this computational strategy on the study of regulatory pathways should provide, along with transcriptomics and metabolomics, data to construct cellular metabolic networks.

  16. Molecular cloning and expression of two isoforms of Vasa gene in Southern catfish Silurus meridionalis

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    HU Chong-Jiang

    2008-12-01

    Full Text Available Two isoforms of Vasa cDNA, derived from the 5′alternative splicing of the same gene, were isolated and characterized in Southern catfish, Silurus meridionalis, by reverse transcription polymerase chain reaction (RT-PCR and rapid amplification of cDNA ends (RACE methods. Analysis of the nucleotide sequences revealed that the full length cDNA of Southern catfish Vasa (scVasa comprises 2525 base pairs (bp with an open reading frame (ORF of 1989 bp, encoding 662 amino acids, while that of Vasa short form (scVasa-s comprises 2438 bp with an ORF of 1926 bp, encoding 641 amino acids. Except the difference in 5′-untranslated region, scVasa-s also lacks a part of the 5′-ORF region found in the scVasa. Both of the two deduced amino acid sequences contain all the eight conserved motifs characteristic to the DEAD-box protein family and four arginine-glycine-glycine motifs unique to Vasa proteins. scVasa showed the highest similarity to Vasa homolog of giebel carp (73.3%. Tissue distribution analysis by RT-PCR revealed that these two isoforms were exclusively expressed in the gonads of both sexes. In adult fish, scVasa was found to be mainly expressed in the primary oocytes at phase Ⅰ and Ⅱ in the ovary while in the spermatogonia and primary spermatocytes in the testis by in situ hybridization. Semi-quantitative RT-PCR analysis showed that the expressions of both scVasa isoforms were much higher in ovarian recrudescent stage (mainly with phase Ⅱ oocytes than in vitellogenic stage (mainly with phase Ⅲ and Ⅳ oocytes [Acta Zoologica Sinica 54(6):1051–1060, 2008].

  17. Somatodendritic and excitatory postsynaptic distribution of neuron-type dystrophin isoform, Dp40, in hippocampal neurons

    Energy Technology Data Exchange (ETDEWEB)

    Fujimoto, Takahiro; Itoh, Kyoko, E-mail: kxi14@koto.kpu-m.ac.jp; Yaoi, Takeshi; Fushiki, Shinji

    2014-09-12

    Highlights: • Identification of dystrophin (Dp) shortest isoform, Dp40, is a neuron-type Dp. • Dp40 expression is temporally and differentially regulated in comparison to Dp71. • Somatodendritic and nuclear localization of Dp40. • Dp40 is localized to excitatory postsynapses. • Dp40 might play roles in dendritic and synaptic functions. - Abstract: The Duchenne muscular dystrophy (DMD) gene produces multiple dystrophin (Dp) products due to the presence of several promoters. We previously reported the existence of a novel short isoform of Dp, Dp40, in adult mouse brain. However, the exact biochemical expression profile and cytological distribution of the Dp40 protein remain unknown. In this study, we generated a polyclonal antibody against the NH{sub 2}-terminal region of the Dp40 and identified the expression profile of Dp40 in the mouse brain. Through an analysis using embryonic and postnatal mouse cerebrums, we found that Dp40 emerged from the early neonatal stages until adulthood, whereas Dp71, an another Dp short isoform, was highly detected in both prenatal and postnatal cerebrums. Intriguingly, relative expressions of Dp40 and Dp71 were prominent in cultured dissociated neurons and non-neuronal cells derived from mouse hippocampus, respectively. Furthermore, the immunocytological distribution of Dp40 was analyzed in dissociated cultured neurons, revealing that Dp40 is detected in the soma and its dendrites, but not in the axon. It is worthy to note that Dp40 is localized along the subplasmalemmal region of the dendritic shafts, as well as at excitatory postsynaptic sites. Thus, Dp40 was identified as a neuron-type Dp possibly involving dendritic and synaptic functions.

  18. Deficiency in the mouse mitochondrial adenine nucleotide translocator isoform 2 gene is associated with cardiac noncompaction.

    Science.gov (United States)

    Kokoszka, Jason E; Waymire, Katrina G; Flierl, Adrian; Sweeney, Katelyn M; Angelin, Alessia; MacGregor, Grant R; Wallace, Douglas C

    2016-08-01

    The mouse fetal and adult hearts express two adenine nucleotide translocator (ANT) isoform genes. The predominant isoform is the heart-muscle-brain ANT-isoform gene 1 (Ant1) while the other is the systemic Ant2 gene. Genetic inactivation of the Ant1 gene does not impair fetal development but results in hypertrophic cardiomyopathy in postnatal mice. Using a knockin X-linked Ant2 allele in which exons 3 and 4 are flanked by loxP sites combined in males with a protamine 1 promoter driven Cre recombinase we created females heterozygous for a null Ant2 allele. Crossing the heterozygous females with the Ant2(fl), PrmCre(+) males resulted in male and female ANT2-null embryos. These fetuses proved to be embryonic lethal by day E14.5 in association with cardiac developmental failure, immature cardiomyocytes having swollen mitochondria, cardiomyocyte hyperproliferation, and cardiac failure due to hypertrabeculation/noncompaction. ANTs have two main functions, mitochondrial-cytosol ATP/ADP exchange and modulation of the mitochondrial permeability transition pore (mtPTP). Previous studies imply that ANT2 biases the mtPTP toward closed while ANT1 biases the mtPTP toward open. It has been reported that immature cardiomyocytes have a constitutively opened mtPTP, the closure of which signals the maturation of cardiomyocytes. Therefore, we hypothesize that the developmental toxicity of the Ant2 null mutation may be the result of biasing the cardiomyocyte mtPTP to remain open thus impairing cardiomyocyte maturation and resulting in cardiomyocyte hyperproliferation and failure of trabecular maturation. This article is part of a Special Issue entitled 'EBEC 2016: 19th European Bioenergetics Conference, Riva del Garda, Italy, July 2-6, 2016', edited by Prof. Paolo Bernardi. PMID:27048932

  19. Compensatory expression and substrate inducibility of γ-glutamyl transferase GGT2 isoform in Arabidopsis thaliana

    OpenAIRE

    Destro, Tiziana; Prasad, Dinesh; Martignago, Damiano; Lliso Bernet, Ignacio; Trentin, Anna Rita; Renu, Indu Kumari; Ferretti, Massimo; Masi, Antonio

    2010-01-01

    γ-Glutamyl transferases (GGT; EC 2.3.2.2) are glutathione-degrading enzymes that are represented in Arabidopsis thaliana by a small gene family of four members. Two isoforms, GGT1 and GGT2, are apoplastic, sharing broad similarities in their amino acid sequences, but they are differently expressed in the tissues: GGT1 is expressed in roots, leaves, and siliques, while GGT2 was thought to be expressed only in siliques. It is demonstrated here that GGT2 is also expressed in wild-type roots, alb...

  20. ApoE Isoform-Dependent Deficits in Extinction of Contextual Fear Conditioning

    OpenAIRE

    Olsen, Reid H. J.; Agam, Mati; Davis, Matthew James; Raber, Jacob

    2012-01-01

    The three major human apoE isoforms (apoE2, apoE3, and apoE4) are encoded by distinct alleles (ε2, ε3, and ε4). Compared to ε3, ε4 is associated with increased risk to develop Alzheimer’s disease (AD), cognitive impairments in Parkinson’s disease (PD), and other conditions. In contrast, a recent study indicated an increased susceptibility to the recurring and re-experiencing symptom cluster of Post Traumatic Stress Disorder (PTSD), as well as related memory impairments, in patients carrying a...

  1. Identification of p53 and Its Isoforms in Human Breast Carcinoma Cells

    OpenAIRE

    Zorka Milićević; Vladan Bajić; Lada Živković; Jelena Kasapović; Uroš Andjelković; Biljana Spremo-Potparević

    2014-01-01

    In breast carcinoma, disruption of the p53 pathway is one of the most common genetic alterations. The observation that the p53 can express multiple protein isoforms adds a novel level of complexity to the outcome of p53 mutations. p53 expression was analysed by Western immunoblotting and immunohistochemistry using monoclonal antibodies DO-7, Pab240, and polyclonal antiserum CM-1. The more frequently p53-positive nuclear staining has been found in the invasive breast tumors. One of the most in...

  2. Isoforms and Functions of NAD(P)H Oxidase at the Macula Densa

    OpenAIRE

    Zhang, Rui; Harding, Pamela; Garvin, Jeffery L.; Juncos, Ramiro; Peterson, Ed; Juncos, Luis A.; Liu, Ruisheng

    2009-01-01

    Macula densa cells produce superoxide (O2-) during tubuloglomerular feedback primarily via NAD(P)H oxidase (NOX). The purpose of the present study was to determine NOXs expressed by the macula densa, and the role of each one in NaCl-induced O2- production. To identify which isoforms are expressed, we applied single cell RT-PCR to macula densa cells isolated by laser capture microdissection, and to MMDD1 cells (a macula densa-like cell line). The captured cells expressed nNOS (marker of macula...

  3. Homozygous carnitine palmitoyltransferase 1b (muscle isoform) deficiency is lethal in the mouse

    OpenAIRE

    Ji, Shaonin; You, Yun; Kerner, Janos; Hoppel, Charles L.; Schoeb, Trenton R.; Chick, Wallace S H; Hamm, Doug A.; Sharer, J. Daniel; Wood, Philip A.

    2007-01-01

    Carnitine palmitoyltransferase-1 (CPT-1) catalyzes the rate-limiting step of mitochondrial β-oxidation of long chain fatty acids (LCFA), the most abundant fatty acids in mammalian membranes and in energy metabolism. Human deficiency of the muscle isoform CPT-1b is poorly understood. In the current study, embryos with a homozygous knockout of Cpt-1b were lost before embryonic day 9.5 − 11.5. Also, while there were normal percentages of CPT-1b+/−pups born from both male and female CPT-1b+/− mic...

  4. Characterization of Affinity-Purified Isoforms of Acinetobacter calcoaceticus Y1 Glutathione Transferases

    OpenAIRE

    Chin-Soon Chee; Irene Kit-Ping Tan; Zazali Alias

    2014-01-01

    Glutathione transferases (GST) were purified from locally isolated bacteria, Acinetobacter calcoaceticus Y1, by glutathione-affinity chromatography and anion exchange, and their substrate specificities were investigated. SDS-polyacrylamide gel electrophoresis revealed that the purified GST resolved into a single band with a molecular weight (MW) of 23 kDa. 2-dimensional (2-D) gel electrophoresis showed the presence of two isoforms, GST1 (pI 4.5) and GST2 (pI 6.2) with identical MW. GST1 was r...

  5. RAS and RHO Families of GTPases Directly Regulate Distinct Phosphoinositide 3-Kinase Isoforms

    OpenAIRE

    Fritsch, Ralph; de Krijger, Inge; Fritsch, Kornelia; George, Roger; Reason, Beth; Kumar, Madhu S.; Diefenbacher, Markus; Stamp, Gordon; Downward, Julian

    2013-01-01

    Summary RAS proteins are important direct activators of p110α, p110γ, and p110δ type I phosphoinositide 3-kinases (PI3Ks), interacting via an amino-terminal RAS-binding domain (RBD). Here, we investigate the regulation of the ubiquitous p110β isoform of PI3K, implicated in G-protein-coupled receptor (GPCR) signaling, PTEN-loss-driven cancers, and thrombocyte function. Unexpectedly, RAS is unable to interact with p110β, but instead RAC1 and CDC42 from the RHO subfamily of small GTPases bind an...

  6. Distribution of myosin heavy chain isoforms in muscular dystrophy: insights into disease pathology

    Science.gov (United States)

    Beedle, Aaron M

    2016-01-01

    Myosin heavy chain isoforms are an important component defining fiber type specific properties in skeletal muscle, such as oxidative versus glycolytic metabolism, rate of contraction, and fatigability. While the molecular mechanisms that underlie specification of the different fiber types are becoming clearer, how this programming becomes disrupted in muscular dystrophy and the functional consequences of fiber type changes in disease are not fully resolved. Fiber type changes in disease, with specific focus on muscular dystrophies caused by defects in the dystrophin glycoprotein complex, are discussed. PMID:27430020

  7. Comparison of fecal pyruvate kinase isoform M2 and calprotectin in acute diarrhea in hospitalized children

    OpenAIRE

    Czub, Elzbieta; Jan K. Nowak; Moczko, Jerzy; Lisowska, Aleksandra; Banaszkiewicz, Aleksandra; Banasiewicz, Tomasz; Walkowiak, Jaroslaw

    2014-01-01

    Fecal concentrations of pyruvate kinase isoform M2 (M2-PK) and calprotectin (FC) serve as biomarkers of inflammation of gastrointestinal mucosa. The value of M2-PK in discriminating between patients with viral and bacterial acute diarrhea (AD) is currently unknown. We analyzed M2-PK and FC concentrations in fifty hospitalized children with AD (29 of which were caused by rotavirus and 21 by Salmonella enteritidis) as well as 32 healthy subjects. There was no difference in the areas under the r...

  8. Molecular cloning and expression of two isoforms of Vasa gene in Southern catfish Silurus meridionalis

    OpenAIRE

    HU Chong-Jiang; WU, Feng-Rui; Liu, Zhi-Hao; HUANG Bao-Feng; Zhang, Yao-Guang; Wang, De-Shou

    2008-01-01

    Two isoforms of Vasa cDNA, derived from the 5′alternative splicing of the same gene, were isolated and characterized in Southern catfish, Silurus meridionalis, by reverse transcription polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends (RACE) methods. Analysis of the nucleotide sequences revealed that the full length cDNA of Southern catfish Vasa (scVasa) comprises 2525 base pairs (bp) with an open reading frame (ORF) of 1989 bp, encoding 662 amino acids, while that of Va...

  9. Yin-Yang Regulation of Adiponectin Signaling by APPL Isoforms in Muscle Cells*

    OpenAIRE

    Wang, Changhua; Xin, Xiaoban; Xiang, Ruihua; Ramos, Fresnida J.; Liu, Meilian; Lee, Hak Joo; Chen, Hongzhi; Mao, Xuming; Kikani, Chintan K.; Liu, Feng; Dong, Lily Q.

    2009-01-01

    APPL1 is a newly identified adiponectin receptor-binding protein that positively mediates adiponectin signaling in cells. Here we report that APPL2, an isoform of APPL1 that forms a dimer with APPL1, can interacts with both AdipoR1 and AdipoR2 and acts as a negative regulator of adiponectin signaling in muscle cells. Overexpression of APPL2 inhibits the interaction between APPL1 and AdipoR1, leading to down-regulation of adiponectin signaling in C2C12 myotubes. In contrast, suppressing APPL2 ...

  10. Correction of the N-terminal sequences of the human plastin isoforms by using anchored polymerase chain reaction: identification of a potential calcium-binding domain.

    OpenAIRE

    Lin, C. S.; Aebersold, R H; Leavitt, J

    1990-01-01

    Plastins are a family of at least three cytoplasmic protein isoforms that are expressed differentially between cells of the hematopoietic lineages and cells of solid tissues. Expression of the L-plastin isoform appears to be restricted to replicating blood cells, and the two T-plastin isoforms appear to be restricted to replicating cells of solid tissues. However, L-plastin is induced in many human solid tumor-derived cells. We used the anchored polymerase chain reaction technique to amplify ...

  11. α-Actinin-2 deficiency results in sarcomeric defects in zebrafish that cannot be rescued by α-actinin-3 revealing functional differences between sarcomeric isoforms

    OpenAIRE

    Gupta, Vandana; Discenza, Marie; Guyon, Jeffrey R; Kunkel, Louis M.; Beggs, Alan H.

    2012-01-01

    α-Actinins are actin-binding proteins that can be broadly divided into Ca2+-sensitive cytoskeletal and Ca2+-insensitive sarcomeric isoforms. To date, little is known about functional differences between the isoforms due to their indistinguishable activities in most in vitro assays. To identify functional differences in vivo between sarcomeric isoforms, we employed computational and molecular approaches to characterize the zebrafish (Danio rerio) genome, which contains orthologoues of each hum...

  12. Properties of the six isoforms of p63: p53-like regulation in response to genotoxic stress and cross talk with DeltaNp73.

    Science.gov (United States)

    Petitjean, A; Ruptier, C; Tribollet, V; Hautefeuille, A; Chardon, F; Cavard, C; Puisieux, A; Hainaut, P; Caron de Fromentel, C

    2008-02-01

    TP63, a member of the TP53 gene family, encodes two groups of three isoforms (alpha, beta and gamma). The TAp63 isoforms act as transcription factors. The DeltaNp63 isoforms lack the main transcription activation domain and act as dominant-negative inhibitors of transactivation (TA) isoforms. To clarify the role of these isoforms and to better understand their functional overlap with p53, we ectopically expressed each p63 isoform in the p53-null hepatocellular carcinoma cell line Hep3B. All TA isoforms, as well as DeltaNp63alpha, had a half-life of 8 h. As expected, TA isoforms differed in their transcriptional activities toward genes regulated by p53, TAp63gamma being the most active form. In contrast, DeltaNp63 isoforms were transcriptionally inactive on genes studied and inhibited TA isoforms in a dose-dependent manner. When stably expressed in polyclonal cell populations, TAp63beta and gamma isoforms were undetectable. However, when treated with doxorubicin (DOX), p63 proteins rapidly accumulated in the cells. This stabilization was associated with an increase in phosphorylation. Strikingly, in DOX-treated polyclonal populations, increase in TAp63 levels was accompanied by overexpression of DeltaNp73. This observation suggests complex regulatory cross talks between the different isoforms of the p53 family. In conclusion, p63 exhibits several transcriptional and stress-response properties similar to those of p53, suggesting that p63 activities should be taken into consideration in approaches to improve cancer therapies based on genotoxic agents. PMID:18048390

  13. Cooperation between two ClpB isoforms enhances the recovery of the recombinant β-galactosidase from inclusion bodies

    International Nuclear Information System (INIS)

    Highlights: ► An important role of synergistic cooperation between the two ClpB isoforms. ► Both ClpB isoforms are associated with IBs of β-galactosidase. ► ClpB is a key chaperone in IB protein release. -- Abstract: Bacterial ClpB is a molecular chaperone that solubilizes and reactivates aggregated proteins in cooperation with the DnaK chaperone system. The mechanism of protein disaggregation mediated by ClpB is linked to translocation of substrates through the central channel within the ring-hexameric structure of ClpB. Two isoforms of ClpB are produced in vivo: the full-length ClpB95 and the truncated ClpB80 (ClpBΔN), which does not contain the N-terminal domain. The functional specificity of the two ClpB isoforms and the biological role of the N-terminal domain are still not fully understood. Recently, it has been demonstrated that ClpB may achieve its full potential as an aggregate-reactivating chaperone through the functional interaction and synergistic cooperation of its two isoforms. It has been found that the most efficient resolubilization and reactivation of stress-aggregated proteins occurred in the presence of both ClpB95 and ClpB80. In this work, we asked if the two ClpB isoforms functionally cooperate in the solubilization and reactivation of proteins from insoluble inclusion bodies (IBs) in Escherichia coli cells. Using the model β-galactosidase fusion protein (VP1LAC), we found that solubilization and reactivation of enzymes entrapped in IBs occurred more efficiently in the presence of ClpB95 with ClpB80 than with either ClpB95 or ClpB80 alone. The two isoforms of ClpB chaperone acting together enhanced the solubility and enzymatic activity of β-galactosidase sequestered into IBs. Both ClpB isoforms were associated with IBs of β-galactosidase, what demonstrates their affinity to this type of aggregates. These results demonstrate a synergistic cooperation between the two isoforms of ClpB chaperone. In addition, no significant recovery of

  14. Cooperation between two ClpB isoforms enhances the recovery of the recombinant {beta}-galactosidase from inclusion bodies

    Energy Technology Data Exchange (ETDEWEB)

    Guenther, Izabela [Department of Biochemistry, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk (Poland); Zolkiewski, Michal [Department of Biochemistry, Kansas State University, Manhattan, KS 66506 (United States); Kedzierska-Mieszkowska, Sabina, E-mail: kedzie@biotech.ug.gda.pl [Department of Biochemistry, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk (Poland)

    2012-10-05

    Highlights: Black-Right-Pointing-Pointer An important role of synergistic cooperation between the two ClpB isoforms. Black-Right-Pointing-Pointer Both ClpB isoforms are associated with IBs of {beta}-galactosidase. Black-Right-Pointing-Pointer ClpB is a key chaperone in IB protein release. -- Abstract: Bacterial ClpB is a molecular chaperone that solubilizes and reactivates aggregated proteins in cooperation with the DnaK chaperone system. The mechanism of protein disaggregation mediated by ClpB is linked to translocation of substrates through the central channel within the ring-hexameric structure of ClpB. Two isoforms of ClpB are produced in vivo: the full-length ClpB95 and the truncated ClpB80 (ClpB{Delta}N), which does not contain the N-terminal domain. The functional specificity of the two ClpB isoforms and the biological role of the N-terminal domain are still not fully understood. Recently, it has been demonstrated that ClpB may achieve its full potential as an aggregate-reactivating chaperone through the functional interaction and synergistic cooperation of its two isoforms. It has been found that the most efficient resolubilization and reactivation of stress-aggregated proteins occurred in the presence of both ClpB95 and ClpB80. In this work, we asked if the two ClpB isoforms functionally cooperate in the solubilization and reactivation of proteins from insoluble inclusion bodies (IBs) in Escherichia coli cells. Using the model {beta}-galactosidase fusion protein (VP1LAC), we found that solubilization and reactivation of enzymes entrapped in IBs occurred more efficiently in the presence of ClpB95 with ClpB80 than with either ClpB95 or ClpB80 alone. The two isoforms of ClpB chaperone acting together enhanced the solubility and enzymatic activity of {beta}-galactosidase sequestered into IBs. Both ClpB isoforms were associated with IBs of {beta}-galactosidase, what demonstrates their affinity to this type of aggregates. These results demonstrate a synergistic

  15. Expression profile of Wilms Tumor 1 (WT1) isoforms in undifferentiated and all-trans retinoic acid differentiated neuroblastoma cells

    Science.gov (United States)

    Maugeri, Grazia; D'Amico, Agata Grazia; Rasà, Daniela Maria; Reitano, Rita; Saccone, Salvatore; Federico, Concetta; Parenti, Rosalba; Magro, Gaetano; D'Agata, Velia

    2016-01-01

    Wilms tumor 1 gene (WT1) is a tumor suppressor gene originally identified in nephroblastoma. It is also expressed in neuroblastoma which represents the most aggressive extracranial pediatric tumor. Many evidences have shown that neuroblastoma may undergo maturation, by transforming itself in a more differentiated tumors such as ganglioneuroblastoma and ganglioneuroma, or progressing into a highly aggressive metastatic malignancy. To date, 13 WT1 mRNA alternative splice variants have been identified. However, most of the studies have focused their attention only on isoform of ∼49 kDa. In the present study, it has been investigated the expression pattern of WT1 isoforms in an in vitro model of neuroblastoma consisting in undifferentiated or all-trans retinoic acid (RA) differentiated cells. These latter representing the less malignant phenotype of this tumor. Results have demonstrated that WT1.1-WT1.5, WT1.6-WT1.9, WT1.10 WT1.11-WT1.12 and WT1.13 isoforms are expressed in both groups of cells, but their levels are significantly increased after RA treatment. These data have also been confirmed by immunofluorescence analysis. Moreover, the inhibition of PI3K/Akt and MAPK/ERK, that represent two signalling pathway specifically involved in NB differentiation, induces an overexpression of WT1 isoforms. These data suggest that WT1 isoforms might be involved in differentiation of neuroblastic into mature ganglion cells. PMID:27014421

  16. Expression of the alpha 1, alpha 2 and alpha 3 isoforms of the GABAA receptor in human alcoholic brain.

    Science.gov (United States)

    Lewohl, J M; Crane, D I; Dodd, P R

    1997-03-14

    The expression of the alpha 1, alpha 2 and alpha 3 isoforms of the GABAA receptor was studied in the superior frontal and motor cortices of 10 control, 10 uncomplicated alcoholic and 7 cirrhotic alcoholic cases matched for age and post-mortem delay. The assay was based on competitive RT/PCR using a single set of primers specific to the alpha class of isoform mRNA species, and was normalized against a synthetic cRNA internal standard. The assay was shown to be quantitative for all three isoform mRNA species. Neither the patient's age nor the post-mortem interval significantly affected the expression of any isoform in either cortical area. The profile of expression was shown to be significantly different between the case groups, particularly because alpha 1 expression was raised in both groups of alcoholics of controls. The two groups of alcoholics could be differentiated on the basis of regional variations in alpha 1 expression. In frontal cortex, alpha 1 mRNA expression was significantly increased when uncomplicated alcoholics were compared with control cases whereas alcoholic-cirrhotic cases were not significantly different from either controls or uncomplicated alcoholic cases. In the motor cortex, alpha 1 expression was elevated only when alcoholic-cirrhotic cases were compared with control cases. There was no significant difference between case groups or areas for any other isoform. PMID:9098573

  17. The expression of ELK transcription factors in adult DRG: Novel isoforms, antisense transcripts and upregulation by nerve damage.

    Science.gov (United States)

    Kerr, Niall; Pintzas, Alexander; Holmes, Fiona; Hobson, Sally-Ann; Pope, Robert; Wallace, Mark; Wasylyk, Christine; Wasylyk, Bohdan; Wynick, David

    2010-06-01

    ELK transcription factors are known to be expressed in a number of regions in the nervous system. We show by RT-PCR that the previously described Elk1, Elk3/Elk3b/Elk3c and Elk4 mRNAs are expressed in adult dorsal root ganglia (DRG), together with the novel alternatively spliced isoforms Elk1b, Elk3d and Elk4c/Elk4d/Elk4e. These isoforms are also expressed in brain, heart, kidney and testis. In contrast to Elk3 protein, the novel Elk3d isoform is cytoplasmic, fails to bind ETS binding sites and yet can activate transcription by an indirect mechanism. The Elk3 and Elk4 genes are overlapped by co-expressed Pctk2 (Cdk17) and Mfsd4 genes, respectively, with the potential formation of Elk3/Pctaire2 and Elk4/Mfsd4 sense-antisense mRNA heteroduplexes. After peripheral nerve injury the Elk3 mRNA isoforms are each upregulated approximately 2.3-fold in DRG (P<0.005), whereas the natural antisense Pctaire2 isoforms show only a small increase (21%, P<0.01) and Elk1 and Elk4 mRNAs are unchanged. PMID:20304071

  18. Analysis of knockout mutants reveals non-redundant functions of poly(ADP-ribose)polymerase isoforms in Arabidopsis.

    Science.gov (United States)

    Pham, Phuong Anh; Wahl, Vanessa; Tohge, Takayuki; de Souza, Laise Rosado; Zhang, Youjun; Do, Phuc Thi; Olas, Justyna J; Stitt, Mark; Araújo, Wagner L; Fernie, Alisdair R

    2015-11-01

    The enzyme poly(ADP-ribose)polymerase (PARP) has a dual function being involved both in the poly(ADP-ribosyl)ation and being a constituent of the NAD(+) salvage pathway. To date most studies, both in plant and non-plant systems, have focused on the signaling role of PARP in poly(ADP-ribosyl)ation rather than any role that can be ascribed to its metabolic function. In order to address this question we here used a combination of expression, transcript and protein localization studies of all three PARP isoforms of Arabidopsis alongside physiological analysis of the corresponding mutants. Our analyses indicated that whilst all isoforms of PARP were localized to the nucleus they are also present in non-nuclear locations with parp1 and parp3 also localised in the cytosol, and parp2 also present in the mitochondria. We next isolated and characterized insertional knockout mutants of all three isoforms confirming a complete knockout in the full length transcript levels of the target genes as well as a reduced total leaf NAD hydrolase activity in the two isoforms (PARP1, PARP2) that are highly expressed in leaves. Physiological evaluation of the mutant lines revealed that they displayed distinctive metabolic and root growth characteristics albeit unaltered leaf morphology under optimal growth conditions. We therefore conclude that the PARP isoforms play non-redundant non-nuclear metabolic roles and that their function is highly important in rapidly growing tissues such as the shoot apical meristem, roots and seeds. PMID:26428915

  19. Primary structure, tissue distribution, and chromosomal localization of a novel isoform of lysyl hydroxylase (lysyl hydroxylase 3)

    Science.gov (United States)

    Valtavaara, M; Szpirer, C; Szpirer, J; Myllylä, R

    1998-05-22

    We report characterization of a novel isoform of lysyl hydroxylase (lysyl hydroxylase 3, LH3). The cDNA clones encode a polypeptide of 738 amino acids, including a signal peptide. The amino acid sequence has a high overall identity with LH1 and LH2, the isoforms characterized earlier. Conserved regions are present in the carboxyl-terminal portion of the isoforms and also in the central part of the molecules. Histidine and asparagine residues, which are conserved in the other isoforms and are known to be required for enzymatic activity, are also conserved in the novel isoform. The gene for LH3 (PLOD3) has been assigned to human chromosome 7q36 and rat chromosome 12. Gene expression of LH3 is highly regulated in adult human tissues. A strong hybridization signal, corresponding to an mRNA 2.75 kilobases in size, is obtained in heart, placenta and pancreas on multiple tissue RNA blots. Expression of the cDNA in vitro results in the synthesis of a protein that hydroxylates lysyl residues in collagenous sequences in a non-triple helical conformation. PMID:9582318

  20. PKD3 is the predominant protein kinase D isoform in mouse exocrine pancreas and promotes hormone-induced amylase secretion.

    Science.gov (United States)

    Chen, L Andy; Li, Jing; Silva, Scott R; Jackson, Lindsey N; Zhou, Yuning; Watanabe, Hiroaki; Ives, Kirk L; Hellmich, Mark R; Evers, B Mark

    2009-01-23

    The protein kinase D (PKD) family of serine/threonine kinases, which can be activated by gastrointestinal hormones, consists of three distinct isoforms that modulate a variety of cellular processes including intracellular protein transport as well as constitutive and regulated secretion. Although isoform-specific functions have been identified in a variety of cell lines, the expression and function of PKD isoforms in normal, differentiated secretory tissues is unknown. Here, we demonstrate that PKD isoforms are differentially expressed in the exocrine and endocrine cells of the pancreas. Specifically, PKD3 is the predominant isoform expressed in exocrine cells of the mouse and human pancreas, whereas PKD1 and PKD2 are more abundantly expressed in the pancreatic islets. Within isolated mouse pancreatic acinar cells, PKD3 undergoes rapid membrane translocation, trans-activating phosphorylation, and kinase activation after gastrointestinal hormone or cholinergic stimulation. PKD phosphorylation in pancreatic acinar cells occurs viaaCa2+-independent, diacylglycerol- and protein kinase C-dependent mechanism. PKD phosphorylation can also be induced by physiologic concentrations of secretagogues and by in vivo stimulation of the pancreas. Furthermore, activation of PKD3 potentiates MEK/ERK/RSK (RSK, ribosomal S6 kinase) signaling and significantly enhances cholecystokinin-mediated pancreatic amylase secretion. These findings reveal a novel distinction between the exocrine and endocrine cells of the pancreas and further identify PKD3 as a signaling molecule that promotes hormone-stimulated amylase secretion. PMID:19028687

  1. Progesterone receptor isoform analysis by quantitative real-time polymerase chain reaction in formalin-fixed, paraffin-embedded canine mammary dysplasias and tumors

    DEFF Research Database (Denmark)

    Guil-Luna, S.; Stenvang, Jan; Brünner, Nils;

    2014-01-01

    its isoforms in formalin-fixed, paraffin-embedded tissue samples from canine mammary lesions (4 dysplasias, 10 benign tumors, and 46 carcinomas) using 1-step SYBR Green quantitative real-time polymerase chain reaction (RT-qPCR). Progesterone receptor was expressed in 75% of dysplasias, all benign...... the expression of isoform A versus B. Analysis of progesterone receptor mRNA isoforms by RT-qPCR was successful in routinely formalin-fixed, paraffin-embedded tissue samples and enabled the distribution of isoforms A and B to be identified for the first time in dysplasias, benign tumors, and malignant...

  2. Alternative mRNA Splicing from the Glial Fibrillary Acidic Protein (GFAP) Gene Generates Isoforms with Distinct Subcellular mRNA Localization Patterns in Astrocytes

    DEFF Research Database (Denmark)

    Thomsen, Rune; Daugaard, Tina Fuglsang; Holm, Ida E;

    2013-01-01

    The intermediate filament network of astrocytes includes Glial fibrillary acidic protein (Gfap) as a major component. Gfap mRNA is alternatively spliced resulting in generation of different protein isoforms where Gfapa is the most predominant isoform. The Gfapd isoform is expressed in proliferating...... mRNA localization patterns were dependent on the different 39-exon sequences included in Gfapd and Gfapa mRNA. The presented results show that alternative Gfap mRNA splicing results in isoform-specific mRNA localization patterns with resulting different local mRNA concentration ratios which have...

  3. Interaction between oblongifolin C and UDP-glucuronosyltransferase isoforms in human liver and intestine microsomes.

    Science.gov (United States)

    Gao, Cui; Shi, Rong; Wang, Tianming; Tan, Hongsheng; Xu, Hongxi; Ma, Yueming

    2015-01-01

    1. Oblongifolin C (OC) is a potential natural anticancer candidate, and its metabolic profile has not yet been established. 2. One major OC glucuronidation metabolite (OCG) has been identified in a pool of human liver microsomes (HLMs). Chemical inhibition experiments suggested that OCG was mainly formed by UGT1A. A screen of recombinant UDP-glucuronosyltransferase isoforms (UGTs) indicated that UGT1A1 primarily mediates OC conjugation, with minor contributions from UGT1A3 and UGT1A8. Enzyme kinetic studies showed that UGT1A1 was the main UGT isoform involved in OCG in HLMs. 3. Further investigation suggested that OC is a broad inhibitor of UGTs. Additionally, OC competitively inhibited UGT1A6 with a Ki value of 3.49 ± 0.57 μM, whereas non-competitively inhibited UGT1A10 with a Ki value of 2.12 ± 0.18 μM. 4. Understanding the interaction between OC and UGTs will greatly contribute to future investigations regarding the inter-individual differences in OC metabolism in clinical trials and potential drug-drug interactions. PMID:25714435

  4. Altered expression of progesterone receptor isoforms A and B in human eutopic endometrium in endometriosis patients.

    Science.gov (United States)

    Wölfler, Monika Martina; Küppers, Mareike; Rath, Werner; Buck, Volker Uwe; Meinhold-Heerlein, Ivo; Classen-Linke, Irmgard

    2016-07-01

    Recent data implicate an altered expression of progesterone receptor isoform A (PR-A) and B (PR-B) in the endometrium of endometriosis patients. This prospective exploratory study aimed to precisely determine the PR-A and PR-B expression using immunohistochemical techniques in eutopic endometrium of women with endometriosis compared with disease-free women throughout the menstrual cycle. All symptomatic patients underwent laparoscopy for the diagnosis of endometriosis and histological confirmation of the disease (EO) whereas controls were proven disease-free (CO). In CO samples (n=10) an increased expression of PR-A and PR-B during the proliferative to early secretory phase and a decreased expression of both receptor isoforms during the mid to late secretory phase was ascertained in accordance with previous studies. In patients with endometriosis (n=16) no cycle dependent pattern of PR-A and PR-B expression was identified in contrast to patients without endometriosis. Moreover, in EO samples a huge variety of inter- and intra-individual differences in PR-A and PR-B expression were detected. These data provide further evidence that dysregulation of the PR-A and PR-B expression might contribute to the pathophysiology of endometriosis. PMID:27050108

  5. Secondary structural analysis of the carboxyl-terminal domain from different connexin isoforms.

    Science.gov (United States)

    Spagnol, Gaëlle; Al-Mugotir, Mona; Kopanic, Jennifer L; Zach, Sydney; Li, Hanjun; Trease, Andrew J; Stauch, Kelly L; Grosely, Rosslyn; Cervantes, Matthew; Sorgen, Paul L

    2016-03-01

    The connexin carboxyl-terminal (CxCT) domain plays a role in the trafficking, localization, and turnover of gap junction channels, as well as the level of gap junction intercellular communication via numerous post-translational modifications and protein-protein interactions. As a key player in the regulation of gap junctions, the CT presents itself as a target for manipulation intended to modify function. Specific to intrinsically disordered proteins, identifying residues whose secondary structure can be manipulated will be critical toward unlocking the therapeutic potential of the CxCT domain. To accomplish this goal, we used biophysical methods to characterize CxCT domains attached to their fourth transmembrane domain (TM4). Circular dichroism and nuclear magnetic resonance were complementary in demonstrating the connexin isoforms that form the greatest amount of α-helical structure in their CT domain (Cx45 > Cx43 > Cx32 > Cx50 > Cx37 ≈ Cx40 ≈ Cx26). Studies compared the influence of 2,2,2-trifluoroethanol, pH, phosphorylation, and mutations (Cx32, X-linked Charcot-Marie Tooth disease; Cx26, hearing loss) on the TM4-CxCT structure. While pH modestly influences the CT structure, a major structural change was associated with phosphomimetic substitutions. Since most connexin CT domains are phosphorylated throughout their life cycle, studies of phospho-TM4-CxCT isoforms will be critical toward understanding the role that structure plays in regulating gap junction function. PMID:26542351

  6. Roles and post-translational regulation of cardiac class IIa histone deacetylase isoforms.

    Science.gov (United States)

    Weeks, Kate L; Avkiran, Metin

    2015-04-15

    Cardiomyocyte hypertrophy is an integral component of pathological cardiac remodelling in response to mechanical and chemical stresses in settings such as chronic hypertension or myocardial infarction. For hypertrophy to ensue, the pertinent mechanical and chemical signals need to be transmitted from membrane sensors (such as receptors for neurohormonal mediators) to the cardiomyocyte nucleus, leading to altered transcription of the genes that regulate cell growth. In recent years, nuclear histone deacetylases (HDACs) have attracted considerable attention as signal-responsive, distal regulators of the transcriptional reprogramming that in turn precipitates cardiomyocyte hypertrophy, with particular focus on the role of members of the class IIa family, such as HDAC4 and HDAC5. These histone deacetylase isoforms appear to repress cardiomyocyte hypertrophy through mechanisms that involve protein interactions in the cardiomyocyte nucleus, particularly with pro-hypertrophic transcription factors, rather than via histone deacetylation. In contrast, evidence indicates that class I HDACs promote cardiomyocyte hypertrophy through mechanisms that are dependent on their enzymatic activity and thus sensitive to pharmacological HDAC inhibitors. Although considerable progress has been made in understanding the roles of post-translational modifications (PTMs) such as phosphorylation, oxidation and proteolytic cleavage in regulating class IIa HDAC localisation and function, more work is required to explore the contributions of other PTMs, such as ubiquitination and sumoylation, as well as potential cross-regulatory interactions between distinct PTMs and between class IIa and class I HDAC isoforms. PMID:25362149

  7. Chimeric calcium/calmodulin-dependent protein kinase in tobacco: differential regulation by calmodulin isoforms

    Science.gov (United States)

    Liu, Z.; Xia, M.; Poovaiah, B. W.

    1998-01-01

    cDNA clones of chimeric Ca2+/calmodulin-dependent protein kinase (CCaMK) from tobacco (TCCaMK-1 and TCCaMK-2) were isolated and characterized. The polypeptides encoded by TCCaMK-1 and TCCaMK-2 have 15 different amino acid substitutions, yet they both contain a total of 517 amino acids. Northern analysis revealed that CCaMK is expressed in a stage-specific manner during anther development. Messenger RNA was detected when tobacco bud sizes were between 0.5 cm and 1.0 cm. The appearance of mRNA coincided with meiosis and became undetectable at later stages of anther development. The reverse polymerase chain reaction (RT-PCR) amplification assay using isoform-specific primers showed that both of the CCaMK mRNAs were expressed in anther with similar expression patterns. The CCaMK protein expressed in Escherichia coli showed Ca2+-dependent autophosphorylation and Ca2+/calmodulin-dependent substrate phosphorylation. Calmodulin isoforms (PCM1 and PCM6) had differential effects on the regulation of autophosphorylation and substrate phosphorylation of tobacco CCaMK, but not lily CCaMK. The evolutionary tree of plant serine/threonine protein kinases revealed that calmodulin-dependent kinases form one subgroup that is distinctly different from Ca2+-dependent protein kinases (CDPKs) and other serine/threonine kinases in plants.

  8. Polarizing the Neuron through Sustained Co-expression of Alternatively Spliced Isoforms.

    Science.gov (United States)

    Yap, Karen; Xiao, Yixin; Friedman, Brad A; Je, H Shawn; Makeyev, Eugene V

    2016-05-10

    Alternative splicing (AS) is an important source of proteome diversity in eukaryotes. However, how this affects protein repertoires at a single-cell level remains an open question. Here, we show that many 3'-terminal exons are persistently co-expressed with their alternatives in mammalian neurons. In an important example of this scenario, cell polarity gene Cdc42, a combination of polypyrimidine tract-binding, protein-dependent, and constitutive splicing mechanisms ensures a halfway switch from the general (E7) to the neuron-specific (E6) alternative 3'-terminal exon during neuronal differentiation. Perturbing the nearly equimolar E6/E7 ratio in neurons results in defects in both axonal and dendritic compartments and suggests that Cdc42E7 is involved in axonogenesis, whereas Cdc42E6 is required for normal development of dendritic spines. Thus, co-expression of a precise blend of functionally distinct splice isoforms rather than a complete switch from one isoform to another underlies proper structural and functional polarization of neurons. PMID:27134173

  9. Sodium-calcium exchanger and multiple sodium channel isoforms in intra-epidermal nerve terminals

    Directory of Open Access Journals (Sweden)

    Gasser Andreas

    2010-11-01

    Full Text Available Abstract Background Nociception requires transduction and impulse electrogenesis in nerve fibers which innervate the body surface, including the skin. However, the molecular substrates for transduction and action potential initiation in nociceptors are incompletely understood. In this study, we examined the expression and distribution of Na+/Ca2+ exchanger (NCX and voltage-gated sodium channel isoforms in intra-epidermal free nerve terminals. Results Small diameter DRG neurons exhibited robust NCX2, but not NCX1 or NCX3 immunolabeling, and virtually all PGP 9.5-positive intra-epidermal free nerve terminals displayed NCX2 immunoreactivity. Sodium channel NaV1.1 was not detectable in free nerve endings. In contrast, the majority of nerve terminals displayed detectable levels of expression of NaV1.6, NaV1.7, NaV1.8 and NaV1.9. Sodium channel immunoreactivity in the free nerve endings extended from the dermal boundary to the terminal tip. A similar pattern of NCX and sodium channel immunolabeling was observed in DRG neurons in vitro. Conclusions NCX2, as well as NaV1.6, NaV1.7, NaV1.8 and NaV1.9, are present in most intra-epidermal free nerve endings. The presence of NCX2, together with multiple sodium channel isoforms, in free nerve endings may have important functional implications.

  10. Molecular cloning, genomic organization, and expression of a testicular isoform of hormone-sensitive lipase

    Energy Technology Data Exchange (ETDEWEB)

    Holst, L.S.; Laurell, H.; Holm, C. [Lund Univ. (Sweden)] [and others

    1996-08-01

    By catalyzing the rate-limiting step in adipose tissue lipolysis, hormone-sensitive lipase (HSL) is an important regulator of energy homeostasis. The role and importance of HSL in tissues other than adipose are poorly understood. We report here the cloning and expression of a testicular isoform, designated HSL{sub tes}. Due to an addition of amino acids at the NH{sub 2}-termini, rat and human HSL{sub tes} consist of 1068 and 1076 amino acids, respectively, compared to the 768 and 775 amino acids, respectively, of the adipocyte isoform (HSL{sub adi}). A novel exon of 1.2 kb, encoding the human testis-specific amino acids, was isolated and mapped to the HSL gene, 16 kb upstream of the exons encoding HSL{sub adi}. The transcribed mRNA of 3.9 kb was specifically expressed in testis. No significant similarity with other known proteins was found for the testis-specific sequence. The amino acid composition differs from the HSL{sub adi} sequence, with a notable hydrophilic character and a high content of prolines and glutamines. COS cells, transfected by the 3.9-kb human testis cDNA, expressed a protein of the expected molecular mass (M{sub r} {approximately}120,000) that exhibited catalytic activity similar to that of HSL{sub adi}. Immunocytochemistry localized HSL to elongating spermatids and spermatozoa; HSL was not detected in interstitial cells. 34 refs., 5 figs.

  11. RAS and RHO families of GTPases directly regulate distinct phosphoinositide 3-kinase isoforms.

    Science.gov (United States)

    Fritsch, Ralph; de Krijger, Inge; Fritsch, Kornelia; George, Roger; Reason, Beth; Kumar, Madhu S; Diefenbacher, Markus; Stamp, Gordon; Downward, Julian

    2013-05-23

    RAS proteins are important direct activators of p110α, p110γ, and p110δ type I phosphoinositide 3-kinases (PI3Ks), interacting via an amino-terminal RAS-binding domain (RBD). Here, we investigate the regulation of the ubiquitous p110β isoform of PI3K, implicated in G-protein-coupled receptor (GPCR) signaling, PTEN-loss-driven cancers, and thrombocyte function. Unexpectedly, RAS is unable to interact with p110β, but instead RAC1 and CDC42 from the RHO subfamily of small GTPases bind and activate p110β via its RBD. In fibroblasts, GPCRs couple to PI3K through Dock180/Elmo1-mediated RAC activation and subsequent interaction with p110β. Cells from mice carrying mutations in the p110β RBD show reduced PI3K activity and defective chemotaxis, and these mice are resistant to experimental lung fibrosis. These findings revise our understanding of the regulation of type I PI3K by showing that both RAS and RHO family GTPases directly regulate distinct ubiquitous PI3K isoforms and that RAC activates p110β downstream of GPCRs. PMID:23706742

  12. Mitochondrial Sulfide Detoxification Requires a Functional Isoform O-Acetylserine(thiol)lyase C in Arabidopsis thaliana

    Institute of Scientific and Technical Information of China (English)

    Consolación (A)lvarez; Irene García; Luis C.Romero; Cecilia Gotor

    2012-01-01

    In non-cyanogenic species,the main source of cyanide derives from ethylene and camalexin biosyntheses.In mitochondria,cyanide is a potent inhibitor of the cytochrome c oxidase and is metabolized bythe β-cyanoalanine synthase CYS-C1,catalyzing the conversion of cysteine and cyanide to hydrogen sulfide and β-cyanoalanine.The hydrogen sulfide released also inhibits the cytochrome c oxidase and needs to be detoxified by the O-acetylserine(thiol)lyase mitochondrial isoform,OAS-C,which catalyzes the incorporation of sulfide to O-acetylserine to produce cysteine,thus generating a cyclic pathway in the mitochondria.The loss of functional OAS-C isoforms causes phenotypic characteristics very similar to the loss of the CYS-C1 enzyme,showing defects in root hair formation.Genetic complementation with the OAS-C gene rescues the impairment of root hair elongation,restoring the wild-type phenotype.The mitochondria compromise their capacity to properly detoxify cyanide and the resulting sulfide because the latter cannot re-assimilate into cysteine in the oas-c null mutant.Consequently,we observe an accumulation of sulfide and cyanide and of the alternative oxidase,which is unable to prevent the production of reactive oxygen species probably due to the accumulation of both toxic molecules.Our results allow us to suggest that the significance of OAS-C is related to its role in the proper sulfide and cyanide detoxification in mitochondria.

  13. Fluconazole Binding and Sterol Demethylation in Three CYP51 Isoforms Indicate Differences in Active Site Topology

    Energy Technology Data Exchange (ETDEWEB)

    Bellamine, A.; Lepesheva, Galina I.; Waterman, Mike (Vanderbilt)

    2010-11-16

    14{alpha}-Demethylase (CYP51) is a key enzyme in all sterol biosynthetic pathways (animals, fungi, plants, protists, and some bacteria), catalyzing the removal of the C-14 methyl group following cyclization of squalene. Based on mutations found in CYP51 genes from Candida albicans azole-resistant isolates obtained after fluconazole treatment of fungal infections, and using site-directed mutagenesis, we have found that fluconazole binding and substrate metabolism vary among three different CYP51 isoforms: human, fungal, and mycobacterial. In C. albicans, the Y132H mutant from isolates shows no effect on fluconazole binding, whereas the F145L mutant results in a 5-fold increase in its IC{sub 50} for fluconazole, suggesting that F145 (conserved only in fungal 14{alpha}-demethylases) interacts with this azole. In C. albicans, F145L accounts, in part, for the difference in fluconazole sensitivity reported between mammals and fungi, providing a basis for treatment of fungal infections. The C. albicans Y132H and human Y145H CYP51 mutants show essentially no effect on substrate metabolism, but the Mycobacterium tuberculosis F89H CYP51 mutant loses both its substrate binding and metabolism. Because these three residues align in the three isoforms, the results indicate that their active sites contain important structural differences, and further emphasize that fluconazole and substrate binding are uncoupled properties.

  14. Investigating the role of class-IA PI 3-kinase isoforms in adipocyte differentiation

    International Nuclear Information System (INIS)

    PI 3-kinases, in particular class-IA, are key signalling molecules controlling many cellular processes including growth, proliferation, migration and differentiation. In this study, we have used a collection of isoform selective PI 3-kinase inhibitors to determine whether attenuation of signalling through class-IA PI 3-kinase isoforms will impact adipocyte differentiation. First, we analysed the expression profiles and found that fibroblastic pre-adipocytes express detectable levels of p110α and p110δ and that after differentiation, p110δ levels fall while p110α levels rise, together with C/EBPα and PPARγ. When using specific inhibitors during the differentiation process, we observed that neither p110β nor p110δ inhibition, had any significant effect. In contrast PIK-75, a selective p110α inhibitor completely abolished adipocyte differentiation as assessed by morphology, transcript and protein levels of adipocyte markers. These results indicate that long term treatment with p110α inhibitors could potentially have a severe impact on fat cell numbers in vivo.

  15. Soluble expression and characterization of a GFP-fused pea actin isoform(PEAc1)

    Institute of Scientific and Technical Information of China (English)

    Ai Xiao LIU; Shao Bin ZHANG; Xiao Jing XU; Dong Tao REN; Guo Qin LIU

    2004-01-01

    A pea actin isoform PEAc1 with green fluorescent protein (GFP) fusion to its C-terminus and His-tag to its Nterminus, was expressed in prokaryotic cells in soluble form, and highly purified with Ni-Chelating SepharoseTM Fast Flow column. The purified fusion protein (PEAc1-GFP) efficiently inhibited DNase I activities before polymerization,and activated the myosin Mg-ATPase activities after polymerization. The PEAc 1-GFP also polymerized into green fluorescent filamentous structures with a critical concentration of 0.75 μM. These filamentous structures were labeled by TRITC-phalloidin, a specific agent for staining actin microfilaments, and identified as having 9 nm diameters by negative staining. These results indicated that PEAc1 preserved the essential characteristics of actin even with His-tag and GFP fusion, suggesting a promising potential to use GFP fusion protein in obtainning soluble plant actin isoform to analyze its physical and biochemical properties in vitro. The PEAc 1-GFP was also expressed in tobacco BY2 cells,which offers a new pathway for further studying its distribution and function in vivo.

  16. Isolation and characterization of cytosolic alanine aminotransferase isoforms from starved rat liver.

    Science.gov (United States)

    Vedavathi, M; Girish, K S; Kumar, M Karuna

    2004-12-01

    Alanine is the most effective precursor for gluconeogenesis among amino acids and the initial reaction is catalyzed by alanine aminotransferases (AlaATs). It is a less extensively studied enzyme under starvation and known to that the enzyme activity increases in liver under starvation. The present study describes the purification and characterization of two isoforms of alanine aminotransferases from starved male rat liver under starvation. The molecular mass of isoforms was found to be 17.7 and 112.2 kDa with isoelectric points of 4.2 and 5.3 respectively for AlaAT I and AlaAT II. Both the enzymes showed narrow substrate specificity for L-alanine with different Km for alanine and 2-oxoglutarate. Both the enzymes were glycoprotein in nature. Inhibition, modification and spectroscopic studies showed that both PLP and free-SH groups are directly involved in the enzymatic catalysis. PLP activated both the enzymes with a Km 0.057 mM and 0.2 mM for AlaAT I and II respectively. PMID:15663181

  17. Semi-supervised Learning Predicts Approximately One Third of the Alternative Splicing Isoforms as Functional Proteins

    Directory of Open Access Journals (Sweden)

    Yanqi Hao

    2015-07-01

    Full Text Available Alternative splicing acts on transcripts from almost all human multi-exon genes. Notwithstanding its ubiquity, fundamental ramifications of splicing on protein expression remain unresolved. The number and identity of spliced transcripts that form stably folded proteins remain the sources of considerable debate, due largely to low coverage of experimental methods and the resulting absence of negative data. We circumvent this issue by developing a semi-supervised learning algorithm, positive unlabeled learning for splicing elucidation (PULSE; http://www.kimlab.org/software/pulse, which uses 48 features spanning various categories. We validated its accuracy on sets of bona fide protein isoforms and directly on mass spectrometry (MS spectra for an overall AU-ROC of 0.85. We predict that around 32% of “exon skipping” alternative splicing events produce stable proteins, suggesting that the process engenders a significant number of previously uncharacterized proteins. We also provide insights into the distribution of positive isoforms in various functional classes and into the structural effects of alternative splicing.

  18. The role of telomeres and telomerase reverse transcriptase isoforms in pluripotency induction and maintenance.

    Science.gov (United States)

    Teichroeb, Jonathan H; Kim, Joohwan; Betts, Dean H

    2016-08-01

    Telomeres are linear guanine-rich DNA structures at the ends of chromosomes. The length of telomeric DNA is actively regulated by a number of mechanisms in highly proliferative cells such as germ cells, cancer cells, and pluripotent stem cells. Telomeric DNA is synthesized by way of the ribonucleoprotein called telomerase containing a reverse transcriptase (TERT) subunit and RNA component (TERC). TERT is highly conserved across species and ubiquitously present in their respective pluripotent cells. Recent studies have uncovered intricate associations between telomeres and the self-renewal and differentiation properties of pluripotent stem cells. Interestingly, the past decade's work indicates that the TERT subunit also has the capacity to modulate mitochondrial function, to remodel chromatin structure, and to participate in key signaling pathways such as the Wnt/β-catenin pathway. Many of these non-canonical functions do not require TERT's catalytic activity, which hints at possible functions for the extensive number of alternatively spliced TERT isoforms that are highly expressed in pluripotent stem cells. In this review, some of the established and potential routes of pluripotency induction and maintenance are highlighted from the perspectives of telomere maintenance, known TERT isoform functions and their complex regulation. PMID:26786236

  19. Data on CUX1 isoforms in idiopathic pulmonary fibrosis lung and systemic sclerosis skin tissue sections.

    Science.gov (United States)

    Ikeda, Tetsurou; Fragiadaki, Maria; Shi-Wen, Xu; Ponticos, Markella; Khan, Korsa; Denton, Christopher; Garcia, Patricia; Bou-Gharios, George; Yamakawa, Akio; Morimoto, Chikao; Abraham, David

    2016-09-01

    This data article contains complementary figures related to the research article entitled, "Transforming growth factor-β-induced CUX1 isoforms are associated with fibrosis in systemic sclerosis lung fibroblasts" (Ikeda et al. (2016) [2], http://dx.doi.org/10.1016/j.bbrep.2016.06.022), which presents that TGF-β increased CUX1 binding in the proximal promoter and enhancer of the COL1A2 and regulated COL1. Further, in the scleroderma (SSc) lung and diffuse alveolar damage lung sections, CUX1 localized within the α- smooth muscle actin (α-SMA) positive cells (Fragiadaki et al., 2011) [1], "High doses of TGF-beta potently suppress type I collagen via the transcription factor CUX1" (Ikeda et al., 2016) [2]. Here we show that CUX1 isoforms are localized within α-smooth muscle actin-positive cells in SSc skin and idiopathic pulmonary fibrosis (IPF) lung tissue sections. In particular, at the granular and prickle cell layers in the SSc skin sections, CUX1 and α-SMA are co-localized. In addition, at the fibrotic loci in the IPF lung tissue sections, CUX1 localized within the α-smooth muscle actin (α-SMA) positive cells. PMID:27583344

  20. High-throughput proteomics detection of novel splice isoforms in human platelets.

    LENUS (Irish Health Repository)

    Power, Karen A

    2009-01-01

    Alternative splicing (AS) is an intrinsic regulatory mechanism of all metazoans. Recent findings suggest that 100% of multiexonic human genes give rise to splice isoforms. AS can be specific to tissue type, environment or developmentally regulated. Splice variants have also been implicated in various diseases including cancer. Detection of these variants will enhance our understanding of the complexity of the human genome and provide disease-specific and prognostic biomarkers. We adopted a proteomics approach to identify exon skip events - the most common form of AS. We constructed a database harboring the peptide sequences derived from all hypothetical exon skip junctions in the human genome. Searching tandem mass spectrometry (MS\\/MS) data against the database allows the detection of exon skip events, directly at the protein level. Here we describe the application of this approach to human platelets, including the mRNA-based verification of novel splice isoforms of ITGA2, NPEPPS and FH. This methodology is applicable to all new or existing MS\\/MS datasets.

  1. Smooth muscle actin isoforms: a tug of war between contraction and compliance.

    Science.gov (United States)

    Arnoldi, Richard; Hiltbrunner, Anita; Dugina, Vera; Tille, Jean-Christophe; Chaponnier, Christine

    2013-01-01

    In higher vertebrates, smooth muscle (SM) contains two tissue-specific actin isoforms: α-SMA and γ-SMA, which predominate in vascular and visceral SM, respectively. Whether α-SMA has been extensively studied and recognized for its contractile activity in SM and SM-like cells such as myofibroblasts, myoepithelial and myoid cells, the distribution and role of γ-SMA remained largely unknown. We developed a new specific monoclonal antibody against γ-SMA and confirmed that γ-SMA predominates in the visceral system and is minor in the vascular system, although more expressed in highly compliant veins than in stiff arteries. Contrary to α-SMA, γ-SMA is absent from myofibroblasts in vitro, and in fibrotic diseases in vivo. We raised the hypothesis that, whereas α-SMA is responsible for the "contractile" activity, γ-SMA would be involved in the "compliance" of SM and SM-like cells. Several models support this hypothesis, namely veins vs. arteries and the physiological modifications occurring in the uterus and mammary glands during pregnancy and lactation. Our results suggest that, in addition to enteric smooth muscles, γ-SMA is expressed in all the tissues submitted to an important dilation including veins, gravid uterus, and lactating mammary glands. The hypothesis of two complementary mechanical roles for the two SMA isoforms is sustained by their different intracellular distributions and by functional assays. PMID:23915964

  2. Somatodendritic and excitatory postsynaptic distribution of neuron-type dystrophin isoform, Dp40, in hippocampal neurons.

    Science.gov (United States)

    Fujimoto, Takahiro; Itoh, Kyoko; Yaoi, Takeshi; Fushiki, Shinji

    2014-09-12

    The Duchenne muscular dystrophy (DMD) gene produces multiple dystrophin (Dp) products due to the presence of several promoters. We previously reported the existence of a novel short isoform of Dp, Dp40, in adult mouse brain. However, the exact biochemical expression profile and cytological distribution of the Dp40 protein remain unknown. In this study, we generated a polyclonal antibody against the NH2-terminal region of the Dp40 and identified the expression profile of Dp40 in the mouse brain. Through an analysis using embryonic and postnatal mouse cerebrums, we found that Dp40 emerged from the early neonatal stages until adulthood, whereas Dp71, an another Dp short isoform, was highly detected in both prenatal and postnatal cerebrums. Intriguingly, relative expressions of Dp40 and Dp71 were prominent in cultured dissociated neurons and non-neuronal cells derived from mouse hippocampus, respectively. Furthermore, the immunocytological distribution of Dp40 was analyzed in dissociated cultured neurons, revealing that Dp40 is detected in the soma and its dendrites, but not in the axon. It is worthy to note that Dp40 is localized along the subplasmalemmal region of the dendritic shafts, as well as at excitatory postsynaptic sites. Thus, Dp40 was identified as a neuron-type Dp possibly involving dendritic and synaptic functions. PMID:25152393

  3. Inhibition of Ptychopetalum olacoides on Acetylcholinesterase Isoforms in Brain of Mice

    Institute of Scientific and Technical Information of China (English)

    FIGUEIR(O) Micheli; POCHMANN Daniela; PORCI(U)NCULA Lisiane Oliveira; NUNES Domingos Sávio; ELISABESTKY Elaine

    2012-01-01

    Objective To further characterize the acetylcholinesterase inhibitors (AChE-Is) pattern of Ptychopetalum olacoides ethanol extract (POEE) on the cytosolic globular monomer (G1) and membrane bound globular tetramer (G4) AChE isoforms in brain areas relevant for cognition.Methods The G1and G4 AChE isoforms were prepared according to the reported methods and the determination of AChE activity used was adapted from colorimetric method.Results POEE mostly inhibited G1in hippocampus (75%),and G4 in frontal cortex (58%) and striatum (75%) (P < 0.05).Kinetic analysis indicated that POEE-induced AChE inhibition in hippocampus was of a competitive nature for G1but uncompetitive for G4.Conclusion Considering the high density of cholinergic projection to the cortex and striatum,and the usefulness of conserving cytosolic acetylcholine to replenish synaptic vesicles in a highly active cognition site such as hippocampus,we argue that this could be a desirable profile for a clinically relevant AChE-I.

  4. B cell receptor-mediated apoptosis of human lymphocytes is associated with a new regulatory pathway of Bim isoform expression.

    Science.gov (United States)

    Mouhamad, Shahul; Besnault, Laurence; Auffredou, Marie Thérèse; Leprince, Corinne; Bourgeade, Marie Françoise; Leca, Gérald; Vazquez, Aimé

    2004-02-15

    Studies in Bim-deficient mice have shown that the proapoptotic molecule Bim plays a key role in the control of B cell homeostasis and activation. However, the role of Bim in human B lymphocyte apoptosis is unknown. We show in this study that, depending on the degree of cross-linking, B cell receptors can mediate both Bim-dependent and apparent Bim-independent apoptotic pathways. Cross-linked anti-mu Ab-mediated activation induces an original pathway governing the expression of the various Bim isoforms. This new pathway involves the following three sequential steps: 1) extracellular signal-regulated kinase-dependent phosphorylation of the BimEL isoform, which is produced in large amounts in healthy B cells; 2) proteasome-mediated degradation of phosphorylated BimEL; and 3) increased expression of the shorter apoptotic isoforms BimL and BimS. PMID:14764673

  5. Glycogen synthase isoforms in Synechocystis sp. PCC6803: identification of different roles to produce glycogen by targeted mutagenesis.

    Directory of Open Access Journals (Sweden)

    Sang-Ho Yoo

    Full Text Available Synechocystis sp. PCC6803 belongs to cyanobacteria which carry out photosynthesis and has recently become of interest due to the evolutionary link between bacteria and plant species. Similar to other bacteria, the primary carbohydrate storage source of Synechocystis sp. PCC6803 is glycogen. While most bacteria are not known to have any isoforms of glycogen synthase, analysis of the genomic DNA sequence of Synechocystis sp. PCC6803 predicts that this strain encodes two isoforms of glycogen synthase (GS for synthesizing glycogen structure. To examine the functions of the putative GS genes, each gene (sll1393 or sll0945 was disrupted by double cross-over homologous recombination. Zymogram analysis of the two GS disruption mutants allowed the identification of a protein band corresponding to each GS isoform. Results showed that two GS isoforms (GSI and GSII are present in Synechocystis sp. PCC6803, and both are involved in glycogen biosynthesis with different elongation properties: GSI is processive and GSII is distributive. Total GS activities in the mutant strains were not affected and were compensated by the remaining isoform. Analysis of the branch-structure of glycogen revealed that the sll1393- mutant (GSI- produced glycogen containing more intermediate-length chains (DP 8-18 at the expense of shorter and longer chains compared with the wild-type strain. The sll0945- mutant (GSII- produced glycogen similar to the wild-type, with only a slightly higher proportion of short chains (DP 4-11. The current study suggests that GS isoforms in Synechocystis sp. PCC6803 have different elongation specificities in the biosynthesis of glycogen, combined with ADP-glucose pyrophosphorylase and glycogen branching enzyme.

  6. Role of JNK isoforms in the development of neuropathic pain following sciatic nerve transection in the mouse

    Directory of Open Access Journals (Sweden)

    Manassero Giusi

    2012-05-01

    Full Text Available Abstract Background Current tools for analgesia are often only partially successful, thus investigations of new targets for pain therapy stimulate great interest. Consequent to peripheral nerve injury, c-Jun N-terminal kinase (JNK activity in cells of the dorsal root ganglia (DRGs and spinal cord is involved in triggering neuropathic pain. However, the relative contribution of distinct JNK isoforms is unclear. Using knockout mice for single isoforms, and blockade of JNK activity by a peptide inhibitor, we have used behavioral tests to analyze the contribution of JNK in the development of neuropathic pain after unilateral sciatic nerve transection. In addition, immunohistochemical labelling for the growth associated protein (GAP-43 and Calcitonin Gene Related Peptide (CGRP in DRGs was used to relate injury related compensatory growth to altered sensory function. Results Peripheral nerve injury produced pain–related behavior on the ipsilateral hindpaw, accompanied by an increase in the percentage of GAP43-immunoreactive (IR neurons and a decrease in the percentage of CGRP-IR neurons in the lumbar DRGs. The JNK inhibitor, D-JNKI-1, successfully modulated the effects of the sciatic nerve transection. The onset of neuropathic pain was not prevented by the deletion of a single JNK isoform, leading us to conclude that all JNK isoforms collectively contribute to maintain neuropathy. Autotomy behavior, typically induced by sciatic nerve axotomy, was absent in both the JNK1 and JNK3 knockout mice. Conclusions JNK signaling plays an important role in regulating pain threshold: the inhibition of all of the JNK isoforms prevents the onset of neuropathic pain, while the deletion of a single splice JNK isoform mitigates established sensory abnormalities. JNK inactivation also has an effect on axonal sprouting following peripheral nerve injury.

  7. Transcriptional profiles of glutathione-S-Transferase isoforms, Cyp, and AOE genes in atrazine-exposed zebrafish embryos.

    Science.gov (United States)

    Glisic, Branka; Hrubik, Jelena; Fa, Svetlana; Dopudj, Nela; Kovacevic, Radmila; Andric, Nebojsa

    2016-02-01

    Glutathione-S-transferase (GST) superfamily consists of multiple members involved in xenobiotic metabolism. Expressional pattern of the GST isoforms in adult fish has been used as a biomarker of exposure to environmental chemicals. However, GST transcriptional responses vary across organs, thus requiring a cross-tissue examination of multiple mRNAs for GST profiling in an animal after chemical exposure. Zebrafish embryos express all GST isoforms as adult fish and could therefore represent an alternative model for identification of biomarkers of exposure. To evaluate such a possibility, we studied a set of cytosolic and microsomal GST isoform-specific expression profiles in the zebrafish embryos after exposure to atrazine, a widely used herbicide. Expression of the GST isoforms was compared with that of CYP genes involved in the phase I of xenobiotic metabolism and antioxidant enzyme (AOE) genes. Using quantitative real-time PCR, we showed dynamic changes in the expressional pattern of twenty GST isoforms, cyp1a, cyp3a65, ahr2, and four AOEs in early development of zebrafish. Acute (48 and 72 h) exposure of 24 h-old embryos to atrazine, from environmentally relevant (0.005 mg/L) to high (40 mg/L) concentrations, caused a variety of transient, albeit minor changes (GST isoforms, ahr2 and AOE genes response. However, expression of cyp1a and cyp3a65 mRNA was markedly and consistently induced by high doses of atrazine (5 and 40 mg/L). In summary, an analysis of the response of multiple systems in the zebrafish embryos provided a comprehensive understanding of atrazine toxicity and its potential impact on biological processes. PMID:25158112

  8. Molecular Analysis of Collagen XVIII Reveals Novel Mutations, Presence of a Third Isoform, and Possible Genetic Heterogeneity in Knobloch Syndrome

    Science.gov (United States)

    Suzuki, O. T.; Sertié, A. L.; Der Kaloustian, V. M.; Kok, F.; Carpenter, M.; Murray, J.; Czeizel, A. E.; Kliemann, S. E.; Rosemberg, S.; Monteiro, M.; Olsen, B. R.; Passos-Bueno, M. R.

    2002-01-01

    Knobloch syndrome (KS) is a rare disease characterized by severe ocular alterations, including vitreoretinal degeneration associated with retinal detachment and occipital scalp defect. The responsible gene, COL18A1, has been mapped to 21q22.3, and, on the basis of the analysis of one family, we have demonstrated that a mutation affecting only one of the three COL18A1 isoforms causes this phenotype. We report here the results of the screening of both the entire coding region and the exon-intron boundaries of the COL18A1 gene (which includes 43 exons), in eight unrelated patients with KS. Besides 20 polymorphic changes, we identified 6 different pathogenic changes in both alleles of five unrelated patients with KS (three compound heterozygotes and two homozygotes). All are truncating mutations leading to deficiency of one or all collagen XVIII isoforms and endostatin. We have verified that, in exon 41, the deletion c3514-3515delCT, found in three unrelated alleles, is embedded in different haplotypes, suggesting that this mutation has occurred more than once. In addition, our results provide evidence of nonallelic genetic heterogeneity in KS. We also show that the longest human isoform (NC11-728) is expressed in several tissues (including the human eye) and that lack of either the short variant or all of the collagen XVIII isoforms causes similar phenotypes but that those patients who lack all forms present more-severe ocular alterations. Despite the small sample size, we found low endostatin plasma levels in those patients with mutations leading to deficiency of all isoforms; in addition, it seems that absence of all collagen XVIII isoforms causes predisposition to epilepsy. PMID:12415512

  9. Secretory pathway Ca2+/Mn2+-ATPase isoform 2 and lactation: specific localization of plasmalemmal and secretory pathway Ca2+ pump isoforms in the mammary gland

    Energy Technology Data Exchange (ETDEWEB)

    Faddy, Helen M.; Smart, Chanel E.; Xu, Ren; Lee, Genee Y.; Kenny, Paraic A.; Feng, Mingye; Rao, Rajini; Brown, Melissa A.; Bissell, Mina J.; Roberts-Thomson, Sarah J.; Monteith, Gregory R.

    2008-04-09

    The supply of calcium to the developing neonate via milk is an important physiological process. Until recently the mechanism for the enrichment of milk with calcium was thought to be almost entirely mediated via the secretory pathway. However, recent studies suggest that a specific isoform of the plasma membrane calcium ATPase, PMCA2, is the primary mechanism for calcium transport into milk, highlighting a major role for apical calcium transport. We compared the expression of the recently identified secretory calcium ATPase, SPCA2, and SPCA1, in the mouse mammary gland during different stages of development. SPCA2 levels increased over 35 fold during lactation, while SPCA1 increased only a modest two fold. The potential importance of SPCA2 in lactation was also highlighted by its localization to luminal secretory cells of the mammary gland during lactation, while SPCA1 was expressed throughout the cells of the mammary gland. We also observed major differences in the localization of PMCA2 and PMCA1 during lactation. Using the SCp2 mouse mammary epithelial cell 3D culture model, differences in the sub-cellular distribution of PMCA2 and PMCA1 were clear. These studies highlight the likely specific roles of PMCA2 and SPCA2 in lactation, and link the recently characterized SPCA2 calcium pump to the supply of calcium into milk and the regulation of Golgi resident enzymes important in lactation. They also indicate that calcium transport into milk is a complex interplay between apical and secretory pathways.

  10. Point mutation in the NF2 gene of HEI-193 human schwannoma cells results in the expression of a merlin isoform with attenuated growth suppressive activity

    International Nuclear Information System (INIS)

    Neurofibromatosis type 2 (NF2) is a genetic disorder characterized by the formation of bilateral schwannomas of the eighth cranial nerve. Although the protein product of the NF2 gene (merlin) is a classical tumor suppressor, the mechanism by which merlin suppresses cell proliferation is not fully understood. The availability of isolated tumor cells would facilitate a better understanding of the molecular function of merlin, but primary schwannoma cells obtained from patients grow slowly and do not yield adequate numbers for biochemical analysis. In this study, we have examined the NF2 mutation in HEI-193 cells, an immortalized cell line derived from the schwannoma of an NF2 patient. Previous work showed that the NF2 mutation in HEI-193 cells causes a splicing defect in the NF2 transcript. We have confirmed this result and further identified the resultant protein product as an isoform of merlin previously designated as isoform 3. The level of isoform 3 proteins in HEI-193 cells is comparable to the levels of merlin isoforms 1 and 2 in normal human Schwann cells and several other immortalized cell lines. In contrast to many mutant forms of merlin, isoform 3 is as resistant to proteasomal degradation as isoforms 1 and 2 and can interact with each of these isoforms in vivo. Cell proliferation assays showed that, in NF2-/- mouse embryonic fibroblasts, exogenously expressed merlin isoform 3 does exhibit growth suppressive activity although it is significantly lower than that of identically expressed merlin isoform 1. These results indicate that, although HEI-193 cells have undetectable levels of merlin isoforms 1 and 2, they are, in fact, not a merlin-null model because they express the moderately active growth suppressive merlin isoform 3

  11. Point mutation in the NF2 gene of HEI-193 human schwannoma cells results in the expression of a merlin isoform with attenuated growth suppressive activity

    Energy Technology Data Exchange (ETDEWEB)

    Lepont, Pierig; Stickney, John T.; Foster, Lauren A.; Meng, Jin-Jun; Hennigan, Robert F. [Department of Cell and Cancer Biology, Vontz Center for Molecular Studies, University of Cincinnati College of Medicine, 3125 Eden Avenue, Cincinnati, OH 45267-0521 (United States); Ip, Wallace [Department of Cell and Cancer Biology, Vontz Center for Molecular Studies, University of Cincinnati College of Medicine, 3125 Eden Avenue, Cincinnati, OH 45267-0521 (United States)], E-mail: wallace.ip@uc.edu

    2008-01-01

    Neurofibromatosis type 2 (NF2) is a genetic disorder characterized by the formation of bilateral schwannomas of the eighth cranial nerve. Although the protein product of the NF2 gene (merlin) is a classical tumor suppressor, the mechanism by which merlin suppresses cell proliferation is not fully understood. The availability of isolated tumor cells would facilitate a better understanding of the molecular function of merlin, but primary schwannoma cells obtained from patients grow slowly and do not yield adequate numbers for biochemical analysis. In this study, we have examined the NF2 mutation in HEI-193 cells, an immortalized cell line derived from the schwannoma of an NF2 patient. Previous work showed that the NF2 mutation in HEI-193 cells causes a splicing defect in the NF2 transcript. We have confirmed this result and further identified the resultant protein product as an isoform of merlin previously designated as isoform 3. The level of isoform 3 proteins in HEI-193 cells is comparable to the levels of merlin isoforms 1 and 2 in normal human Schwann cells and several other immortalized cell lines. In contrast to many mutant forms of merlin, isoform 3 is as resistant to proteasomal degradation as isoforms 1 and 2 and can interact with each of these isoforms in vivo. Cell proliferation assays showed that, in NF2{sup -/-} mouse embryonic fibroblasts, exogenously expressed merlin isoform 3 does exhibit growth suppressive activity although it is significantly lower than that of identically expressed merlin isoform 1. These results indicate that, although HEI-193 cells have undetectable levels of merlin isoforms 1 and 2, they are, in fact, not a merlin-null model because they express the moderately active growth suppressive merlin isoform 3.

  12. Expression of the human apoE2 isoform in adipocytes: altered cellular processing and impaired adipocyte lipogenesis

    OpenAIRE

    Huang, Zhi H.; Maeda, Nobuyo; Mazzone, Theodore

    2011-01-01

    Expression of apoE in adipocytes has been shown to have an important role in modulating adipocyte triglyceride (TG) metabolism and gene expression that is independent of circulating and extracellular apoE. The impact of adipocyte expression of common human apoE isoforms was evaluated using adipocytes harvested from human apoE2, -3, and -4 knock-in mice. Expression of the apoE2 isoform was associated with an increase in adipocyte apoE gene expression and apoE synthesis. Newly synthesized apoE2...

  13. Mechanistic insights into isoform-dependent and species-specific regulation of bile salt export pump by farnesoid X receptor

    OpenAIRE

    Song, Xiulong; Chen, Yuan; Valanejad, Leila; Kaimal, Rajani; Yan, Bingfang; Stoner, Matthew; Deng, Ruitang

    2013-01-01

    Expression of bile salt export pump (BSEP) is regulated by the bile acid/farnesoid X receptor (FXR) signaling pathway. Two FXR isoforms, FXRα1 and FXRα2, are predominantly expressed in human liver. We previously showed that human BSEP was isoform-dependently regulated by FXR and diminished with altered expression of FXRα1 and FXRα2 in patients with hepatocellular carcinoma. In this study, we demonstrate that FXRα1 and FXRα2 regulate human BSEP through two distinct FXR responsive elements (FXR...

  14. Specific T-type calcium channel isoforms are associated with distinct burst phenotypes in deep cerebellar nuclear neurons

    OpenAIRE

    Molineux, Michael L.; McRory, John E.; McKay, Bruce E.; Hamid, Jawed; Mehaffey, W. Hamish; Rehak, Renata; Snutch, Terrance P; Gerald W Zamponi; Turner, Ray W

    2006-01-01

    T-type calcium channels are thought to transform neuronal output to a burst mode by generating low voltage-activated (LVA) calcium currents and rebound burst discharge. In this study we assess the expression pattern of the three different T-type channel isoforms (Cav3.1, Cav3.2, and Cav3.3) in cerebellar neurons and focus on their potential role in generating LVA spikes and rebound discharge in deep cerebellar nuclear (DCN) neurons. We detected expression of one or more Cav3 channel isoforms ...

  15. In vivo generation of neurotoxic prion protein: role for hsp70 in accumulation of misfolded isoforms.

    Directory of Open Access Journals (Sweden)

    Pedro Fernandez-Funez

    2009-06-01

    Full Text Available Prion diseases are incurable neurodegenerative disorders in which the normal cellular prion protein (PrP(C converts into a misfolded isoform (PrP(Sc with unique biochemical and structural properties that correlate with disease. In humans, prion disorders, such as Creutzfeldt-Jakob disease, present typically with a sporadic origin, where unknown mechanisms lead to the spontaneous misfolding and deposition of wild type PrP. To shed light on how wild-type PrP undergoes conformational changes and which are the cellular components involved in this process, we analyzed the dynamics of wild-type PrP from hamster in transgenic flies. In young flies, PrP demonstrates properties of the benign PrP(C; in older flies, PrP misfolds, acquires biochemical and structural properties of PrP(Sc, and induces spongiform degeneration of brain neurons. Aged flies accumulate insoluble PrP that resists high concentrations of denaturing agents and contains PrP(Sc-specific conformational epitopes. In contrast to PrP(Sc from mammals, PrP is proteinase-sensitive in flies. Thus, wild-type PrP rapidly converts in vivo into a neurotoxic, protease-sensitive isoform distinct from prototypical PrP(Sc. Next, we investigated the role of molecular chaperones in PrP misfolding in vivo. Remarkably, Hsp70 prevents the accumulation of PrP(Sc-like conformers and protects against PrP-dependent neurodegeneration. This protective activity involves the direct interaction between Hsp70 and PrP, which may occur in active membrane microdomains such as lipid rafts, where we detected Hsp70. These results highlight the ability of wild-type PrP to spontaneously convert in vivo into a protease-sensitive isoform that is neurotoxic, supporting the idea that protease-resistant PrP(Sc is not required for pathology. Moreover, we identify a new role for Hsp70 in the accumulation of misfolded PrP. Overall, we provide new insight into the mechanisms of spontaneous accumulation of neurotoxic PrP and uncover

  16. Functional analysis of Na+/K+-ATPase isoform distribution in rat ventricular myocytes.

    Science.gov (United States)

    Despa, Sanda; Bers, Donald M

    2007-07-01

    The Na(+)/K(+)-ATPase (NKA) is the main route for Na(+) extrusion from cardiac myocytes. Different NKA alpha-subunit isoforms are present in the heart. NKA-alpha1 is predominant, although there is a variable amount of NKA-alpha2 in adult ventricular myocytes of most species. It has been proposed that NKA-alpha2 is localized mainly in T-tubules (TT), where it could regulate local Na(+)/Ca(2+) exchange and thus cardiac myocyte Ca(2+). However, there is controversy as to where NKA-alpha1 vs. NKA-alpha2 are localized in ventricular myocytes. Here, we assess the TT vs. external sarcolemma (ESL) distribution functionally using formamide-induced detubulation of rat ventricular myocytes, NKA current (I(Pump)) measurements and the different ouabain sensitivity of NKA-alpha1 (low) and NKA-alpha2 (high) in rat heart. Ouabain-dependent I(Pump) inhibition in control myocytes indicates a high-affinity NKA isoform (NKA-alpha2, K(1/2) = 0.38 +/- 0.16 microM) that accounts for 29.5 +/- 1.3% of I(Pump) and a low-affinity isoform (NKA-alpha1, K(1/2) = 141 +/- 17 microM) that accounts for 70.5% of I(Pump). Detubulation decreased cell capacitance from 164 +/- 6 to 120 +/- 8 pF and reduced I(Pump) density from 1.24 +/- 0.05 to 1.02 +/- 0.05 pA/pF, indicating that the functional density of NKA is significantly higher in TT vs. ESL. In detubulated myocytes, NKA-alpha2 accounted for only 18.2 +/- 1.1% of I(Pump). Thus, approximately 63% of I(Pump) generated by NKA-alpha2 is from the TT (although TT are only 27% of the total sarcolemma), and the NKA-alpha2/NKA-alpha1 ratio in TT is significantly higher than in the ESL. The functional density of NKA-alpha2 is approximately 4.5 times higher in the T-tubules vs. ESL, whereas NKA-alpha1 is almost uniformly distributed between the TT and ESL. PMID:17392375

  17. The HER4 isoform JM-a/CYT2 relates to improved survival in bladder cancer patients but only if the estrogen receptor α is not expressed

    DEFF Research Database (Denmark)

    Munk, Mathias; Memon, Ashfaque; Poulsen, Steen S;

    2013-01-01

    Abstract Bladder cancer tumors expressing human epidermal growth factor receptor 4 (HER4) demonstrate improved patient survival. HER4 isoforms and estrogen receptor alpha (ER-α) can form chaperone complexes causing cell-proliferation. We wanted to explore if HER4 isoforms and ER-α could correlate...... to poor prognosis in bladder cancers. We developed mRNA assays for HER4 isoforms (JM-a, JM-b, CYT1, and CYT2) and for ER-α. Expression was analyzed in tumors from 85 bladder cancer patients and compared to overall survival (median follow-up of 5.1 years). ER-α was expressed in 38% (n = 32) of tumors...... but did not correlate to survival (p = 0.4698). HER4 was expressed in 42% (n = 36) and in all cases as the ER-α binding isoform JM-a. The JM-a isoform can be alternatively spliced to either a CYT1 isoform (JM-a/CYT1) or a CYT2 isoform (JM-a/CYT2). All HER4 expressing tumors expressed the JM-a/CYT2 isoform...

  18. In vivo analysis of Saccharomyces cerevisiae plasma membrane ATPase Pma1p isoforms with increased in vitro H+/ATP stoichiometry

    NARCIS (Netherlands)

    De Kok, S.; Yilmaz, D.; Daran, J.M.; Pronk, J.T.; Van Maris, A.J.A.

    2012-01-01

    Plasma membrane H+-ATPase isoforms with increased H+/ATP ratios represent a desirable asset in yeast metabolic engineering. In vivo proton coupling of two previously reported Pma1p isoforms (Ser800Ala, Glu803Gln) with increased in vitro H+/ATP stoichiometries was analysed by measuring biomass yields

  19. Expression of 1N3R-Tau isoform inhibits cell proliferation by inducing S phase arrest in N2a cells.

    Directory of Open Access Journals (Sweden)

    Li Li

    Full Text Available Tau is a microtubule-associated protein implicated in neurodegenerative tauopathies. Six tau isoforms are generated from a single gene through alternative splicing of exons 2, 3 and 10 in human brain. Differential expression of tau isoforms has been detected in different brain areas, during neurodevelopment and in neurodegenerative disorders. However, the biological significance of different tau isoforms is not clear. Here, we investigated the individual effect of six different isoforms of tau on cell proliferation and the possible mechanisms by transient expression of eGFP-labeled tau isoform plasmid in N2a cells. Our study showed the transfection efficiency was comparable between different isoforms of tau by examining GFP expression. Compared with other isoforms, we found expression of 1N3R-tau significantly inhibited cell proliferation by Cell Counting Kit-8 assay and BrdU incorporation. Flow cytometry analysis further showed expression of 1N3R-tau induced S phase arrest. Compared with the longest isoform of tau, expression of 1N3R-tau induced cyclin E translocation from the nuclei to cytoplasm, while it did not change the level of cell cycle checkpoint proteins. These data indicate that 1N3R-tau inhibits cell proliferation through inducing S phase arrest.

  20. De novo quence analysis and intact mass measurements for characterization of phycocyanin subunit isoforms from the blue-green alga Aphanizomenon flos-aquae

    DEFF Research Database (Denmark)

    Rinalducci, Sara; Roepstorff, Peter; Zolla, Lello

    2009-01-01

    phycocyanin subunits was also revealed; subsequently Intact Mass Measurements (IMMs) by both MALDI- and ESI-MS supported the detection of these protein isoforms. Finally, we discuss the evolutionary importance of phycocyanin isoforms in cyanobacteria, suggesting the possible use of the phycocyanin operon for...

  1. Characterization and differential expression of protein kinase C isoforms in PC12 cells. Differentiation parallels an increase in PKC beta II.

    Science.gov (United States)

    Wooten, M W; Seibenhener, M L; Soh, Y; Ewald, S J; White, K R; Lloyd, E D; Olivier, A; Parker, P J

    1992-02-17

    Nerve growth factor (NGF) treatment of PC12 cells induced a 2.8-fold increase in protein kinase C activity concomitant with differentiation and acquisition of neuritis. PKC protein isoforms were separated by sequential chromatography on DEAE-Sephacel/hydroxylapatite. A broad peak of PKC activity eluted which corresponded to the alpha PKC isoform. In control cells, message for all six PKC isoforms was detected and expressed as epsilon greater than zeta = gamma greater than delta greater than beta greater than alpha. Western blot of whole cell lysates revealed a large increase in the beta II, while slight changes were observed for the other five PKC isoforms during treatment (1-14 days) with NGF (50 ng/ml). In parallel, coordinate changes in the expression of the individual transcripts for the six isoforms occurred during NGF treatment. Induction and accumulation of PKC beta II may play a role in maintenance of neuronal morphology. PMID:1544425

  2. Comparison of α-amylase isoforms from the midgut of Cerambyx cerdo L. (Coleoptera: Cerambycidae larvae developed in the wild and on an artificial diet

    Directory of Open Access Journals (Sweden)

    Dojnov Biljana

    2010-01-01

    Full Text Available α-Amylase isoforms of Cerambyx cerdo larvae from the wild (ML and SL and reared in the laboratory (ADL were compared. Three amylase isoforms were presented in the SL and ML extracts while two isoforms were presented in the ADL according to zymogram after isoelectric focusing (IEF. All C. cerdo amylase isoforms were acidic proteins (pI < 3.5. Seven amylase isoforms (ACC 1-7 from the midgut of C. cerdo larvae were found in the ML midgut extract, six in the SL extract, and four in the ADL extract according to native PAGE zymogram. The ADL amylase had the highest activity. All crude midgut extracts of C. cerdo larvae were fractionated on a Superose 12 HR column. The molecular mass of the ACC was estimated to be 34 kDa. .

  3. Direct binding and activation of protein kinase C isoforms by steroid hormones.

    LENUS (Irish Health Repository)

    Alzamora, Rodrigo

    2008-10-01

    The non-genomic action of steroid hormones regulates a wide variety of cellular responses including regulation of ion transport, cell proliferation, migration, death and differentiation. In order to achieve such plethora of effects steroid hormones utilize nearly all known signal transduction pathways. One of the key signalling molecules regulating the non-genomic action of steroid hormones is protein kinase C (PKC). It is thought that rapid action of steroids hormones results from the activation of plasma membrane receptors; however, their molecular identity remains elusive. In recent years, an increasing number of studies have pointed at the selective binding and activation of specific PKC isoforms by steroid hormones. This has led to the hypothesis that PKC could act as a receptor as well as a transducer of the non-genomic effects of these hormones. In this review we summarize the current knowledge of the direct binding and activation of PKC by steroid hormones.

  4. Expression of glutamine transporter isoforms in cerebral cortex of rats with chronic hepatic encephalopathy

    DEFF Research Database (Denmark)

    Leke, Renata; Escobar, Thayssa D.C.; Rama Rao, Kakulavarapu V.;

    2015-01-01

    Hepatic encephalopathy (HE) is a neuropsychiatric disorder that occurs due to acute and chronic liver diseases, the hallmark of which is the increased levels of ammonia and subsequent alterations in glutamine synthesis, i.e. conditions associated with the pathophysiology of HE. Under physiological...... conditions, glutamine is fundamental for replenishment of the neurotransmitter pools of glutamate and GABA. The different isoforms of glutamine transporters play an important role in the transfer of this amino acid between astrocytes and neurons. A disturbance in the GABA biosynthetic pathways has been...... described in bile duct ligated (BDL) rats, a well characterized model of chronic HE. Considering that glutamine is important for GABA biosynthesis, altered glutamine transport and the subsequent glutamate/GABA–glutamine cycle efficacy might influence these pathways. Given this potential outcome, the aim of...

  5. Deep proteomics of mouse skeletal muscle enables quantitation of protein isoforms, metabolic pathways and transcription factors

    DEFF Research Database (Denmark)

    Deshmukh, Atul S; Murgia, Marta; Nagaraja, Nagarjuna;

    2015-01-01

    spectrometric (MS) workflow and a strategy to map identifications from the C2C12 cell line model to tissues, we identified a total of 10,218 proteins, including skeletal muscle specific transcription factors like myod1 and myogenin and circadian clock proteins. We obtain absolute abundances for proteins......Skeletal muscle constitutes 40% of individual body mass and plays vital roles in locomotion and whole-body metabolism. Proteomics of skeletal muscle is challenging due to highly abundant contractile proteins that interfere with detection of regulatory proteins. Using a state-of-the art mass...... expressed in a muscle cell line and skeletal muscle, which should serve as a valuable resource. Quantitation of protein isoforms of glucose uptake signaling pathways and in glucose and lipid metabolic pathways provides a detailed metabolic map of the cell line compare to tissue. This revealed unexpectedly...

  6. Molecular cloning and characterization of rat brain 2',3'-cyclic nucleotide 3'-phosphodiesterase isoform 2.

    Science.gov (United States)

    Gravel, M; DeAngelis, D; Braun, P E

    1994-06-15

    We have isolated a cDNA coding for the larger isoform of the rat brain 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNP2), a protein associated with myelination in the central nervous system (CNS). The complete 420 amino acid sequence was deduced from the nucleotide sequence of the cDNA. Sequence comparisons show that rat CNP shares 96% homology with mouse, 84% with bovine, and 86% with human CNP. Errors in the published sequence of rat CNP1 have now been corrected. Comparisons with other proteins reveal several interesting conserved motifs, including two leucine repeat heptads, and two consensus motifs for phosphorylation in the N-terminal domain of CNP2. PMID:7932861

  7. Two isoforms of plant RAD23 complement a UV-sensitive rad23 mutant in yeast

    International Nuclear Information System (INIS)

    DNA repair by nucleotide excision (NER) has been demonstrated in plant cells at the biochemical level but until now none of the molecular components of the plant NER complex has been identified. In this paper, the cloning and characterization of two isoforms of RAD23 from carrot (Daucus carota L.) are reported. It has been suggested that RAD23 in yeast is an assembly factor of the NER complex required for transcription-coupled repair as well as efficient overall genome repair. A functional assay demonstrated that both plant homologues complement the UV-sensitive phenotype of a rad23 deletion mutant of yeast. This result suggests that homologous polypeptides may catalyse NER in plants and yeast and, possibly, by a similar mechanism

  8. Nanoscale elucidation of Na,K-ATPase isoforms in dendritic spines

    CERN Document Server

    Liebmann, Thomas; Aperia, Anita; Brismar, Hjalmar

    2013-01-01

    The dimensions of neuronal synapses suggest that optical super-resolution imaging methods are necessary for thorough investigation of protein distributions and interactions. Nanoscopic evaluation of neuronal samples has presented practical hurdles, but advancing methods are making synaptic protein topology and quantification measurements feasible. This work explores the application of Photoactivated Localization Microscopy (PALM) pointilistic super-resolution imaging for investigation of the membrane bound sodium pump, the Na,K-ATPase, in matured neurons. Two isoforms of the sodium pump (ATP1a1 and ATP1a3) were studied in cultured neurons using the PALM-compatible fluorescent proteins PAGFP and mEos. Nanoscopic imaging reveals a compartmentalized distribution of sodium pumps in dendritic spines. Several nanoclusters of pumps are typically found in the spine head and relatively few in the spine neck. The density of sodium pumps was estimated from a quantification of detected single molecules to 600-800 pump co...

  9. HER4 and its cytoplasmic isoforms are associated with progression-free survival of malignant melanoma

    DEFF Research Database (Denmark)

    Nielsen, Trine O; Poulsen, Steen Seier; Journe, Fabrice;

    2014-01-01

    RNA quantification was carried out of all four EGF receptors (EGFR, HER2, HER3, and HER4) and the HER4 cytoplasmic isoforms in lymph node metastases from patients with malignant melanoma. We related their expression to progression of the disease. HER4 expression was found to be an indicator of short progression......-free survival (P=0.0340). Interestingly, of the two cytoplasmic splice variants of HER4, the association of CYT1 (P=0.0176) with progression-free survival was more pronounced than that for CYT2 (P=0.0458). Also, HER3 was associated with progression-free survival (P=0.0169), whereas no association was found for...

  10. Impact of resistance exercise during bed rest on skeletal muscle sarcopenia and myosin isoform distribution

    Science.gov (United States)

    Bamman, M. M.; Clarke, M. S.; Feeback, D. L.; Talmadge, R. J.; Stevens, B. R.; Lieberman, S. A.; Greenisen, M. C.

    1998-01-01

    Because resistance exercise (REx) and bed-rest unloading (BRU) are associated with opposing adaptations, our purpose was to test the efficacy of REx against the effects of 14 days of BRU on the knee-extensor muscle group. Sixteen healthy men were randomly assigned to no exercise (NoEx; n = 8) or REx (n = 8). REx performed five sets of leg press exercise with 80-85% of one repetition maximum (1 RM) every other day during BRU. Muscle samples were removed from the vastus lateralis muscle by percutaneous needle biopsy. Myofiber distribution was determined immunohistochemically with three monoclonal antibodies against myosin heavy chain (MHC) isoforms (I, IIa, IIx). MHC distribution was further assessed by quantitative gel electrophoresis. Dynamic 1-RM leg press and unilateral maximum voluntary isometric contraction (MVC) were determined. Maximal neural activation (root mean squared electromyogram) and rate of torque development (RTD) were measured during MVC. Reductions (P exercise for astronauts in microgravity.

  11. N(ε)-Carboxymethyl Modification of Lysine Residues in Pathogenic Prion Isoforms.

    Science.gov (United States)

    Choi, Yeong-Gon; Shin, Hae-Young; Kim, Jae-Il; Choi, Eun-Kyoung; Carp, Richard I; Kim, Yong-Sun

    2016-07-01

    The most prominent hallmark of prion diseases is prion protein conversion and the subsequent deposition of the altered prions, PrP(Sc), at the pathological sites of affected individuals, particularly in the brain. A previous study has demonstrated that the N-terminus of the pathogenic prion isoform (PrP(Sc)) is modified with advanced glycation end products (AGEs), most likely at one or more of the three Lys residues (positions 23, 24, and 27) in the N-terminus (23KKRPKP28). The current study investigated whether N(ε)-(carboxymethyl)lysine (CML), a major AGE form specific to Lys residues produced by nonenzymatic glycation, is an AGE adduct of the N-terminus of PrP(Sc). We show that CML is linked to at least one Lys residue at the N-terminus of PrP(Sc) in 263K prion-infected hamster brains and at least one of the eight Lys residues (positions 101, 104, 106, 110, 185, 194, 204, and 220) in the proteinase K (PK)-resistant core region of PrP(Sc). The nonenzymatic glycation of the Lys residue(s) of PrP(Sc) with CML likely occurs in the widespread prion-deposit areas within infected brains, particularly in some of the numerous tyrosine hydroxylase-positive thalamic and hypothalamic nuclei. CML glycation does not occur in PrP(C) but is seen in the pathologic PrP(Sc) isoform. Furthermore, the modification of PrP(Sc) with CML may be closely involved in prion propagation and deposition in pathological brain areas. PMID:25983034

  12. Trangenic misexpression of the differentiation-specific desmocollin isoform 1 in basal keratinocytes.

    Science.gov (United States)

    Henkler, F; Strom, M; Mathers, K; Cordingley, H; Sullivan, K; King, I

    2001-01-01

    Keratinocytes undergoing terminal differentiation are characterized by well-defined changes in protein expression, which contribute towards the transformation of cytoarchitecture and epithelial morphology. Characteristic patterns of desmosomal cadherins are tightly regulated and distinct isoforms are expressed during development and differentiation of epithelial tissues. Desmocollin-1 is strictly confined to suprabasal layers of epidermis, but it is absent in mitotically active, basal keratinocytes. This raises the question of whether basal desmocollin-1 could alter desmosomal functions and compromise keratinocyte proliferation, stratification, or early differentiation in skin. In this study, we misexpressed human desmocollin-1 in mouse epidermis, under control of the keratin-14 promoter. Transgenic animals were generated, which showed a specific expression of transgenic human desmocollin-1 in epidermal basal cells. High level transgenic expression, which was equal to or greater than endogenous protein levels, was observed in mice with multiple copy integration of the transgene. A punctate distribution of desmocollin-1 was demonstrated at the cell membrane by indirect immunofluorescence. Transgenic human desmocollin-1 colocalized with endogenous desmosomal marker proteins, indicating efficient incorporation into desmosomes. Transgenic mice did not display any obvious abnormalities, either in the histology of skin and hair follicles, or in the ultrastructure of desmosomes. These observations suggest that desmocollin-1 can function as a desmosomal cadherin both in basal and suprabasal cells. We propose that the differentiation-specific desmocollin isoforms desmocollin-1 and desmocollin-3 are functionally equivalent in basal epidermal cells and suggest that their changing expression patterns are markers, but not regulators, of the initial steps in keratinocyte differentiation. PMID:11168810

  13. Identification and Analysis of the Role of Superoxide Dismutases Isoforms in the Pathogenesis of Paracoccidioides spp.

    Directory of Open Access Journals (Sweden)

    Diana Tamayo

    2016-03-01

    Full Text Available The ability of Paracoccidioides to defend itself against reactive oxygen species (ROS produced by host effector cells is a prerequisite to survive. To counteract these radicals, Paracoccidioides expresses, among different antioxidant enzymes, superoxide dismutases (SODs. In this study, we identified six SODs isoforms encoded by the Paracoccidioides genome. We determined gene expression levels of representative isolates of the phylogenetic lineages of Paracoccidioides spp. (S1, PS2, PS3 and Pb01-like using quantitative RT-PCR. Assays were carried out to analyze SOD gene expression of yeast cells, mycelia cells, the mycelia-to-yeast transition and the yeast-to-mycelia germination, as well as under treatment with oxidative agents and during interaction with phagocytic cells. We observed an increased expression of PbSOD1 and PbSOD3 during the transition process, exposure to oxidative agents and interaction with phagocytic cells, suggesting that these proteins could assist in combating the superoxide radicals generated during the host-pathogen interaction. Using PbSOD1 and PbSOD3 knockdown strains we showed these genes are involved in the response of the fungus against host effector cells, particularly the oxidative stress response, and in a mouse model of infection. Protein sequence analysis together with functional analysis of knockdown strains seem to suggest that PbSOD3 expression is linked with a pronounced extracellular activity while PbSOD1 seems more related to intracellular requirements of the fungus. Altogether, our data suggests that P. brasiliensis actively responds to the radicals generated endogenously during metabolism and counteracts the oxidative burst of immune cells by inducing the expression of SOD isoforms.

  14. Identification and Analysis of the Role of Superoxide Dismutases Isoforms in the Pathogenesis of Paracoccidioides spp.

    Science.gov (United States)

    Tamayo, Diana; Muñoz, José F; Lopez, Ángela; Urán, Martha; Herrera, Juan; Borges, Clayton L; Restrepo, Ángela; Soares, Celia M; Taborda, Carlos P; Almeida, Agostinho J; McEwen, Juan G; Hernández, Orville

    2016-03-01

    The ability of Paracoccidioides to defend itself against reactive oxygen species (ROS) produced by host effector cells is a prerequisite to survive. To counteract these radicals, Paracoccidioides expresses, among different antioxidant enzymes, superoxide dismutases (SODs). In this study, we identified six SODs isoforms encoded by the Paracoccidioides genome. We determined gene expression levels of representative isolates of the phylogenetic lineages of Paracoccidioides spp. (S1, PS2, PS3 and Pb01-like) using quantitative RT-PCR. Assays were carried out to analyze SOD gene expression of yeast cells, mycelia cells, the mycelia-to-yeast transition and the yeast-to-mycelia germination, as well as under treatment with oxidative agents and during interaction with phagocytic cells. We observed an increased expression of PbSOD1 and PbSOD3 during the transition process, exposure to oxidative agents and interaction with phagocytic cells, suggesting that these proteins could assist in combating the superoxide radicals generated during the host-pathogen interaction. Using PbSOD1 and PbSOD3 knockdown strains we showed these genes are involved in the response of the fungus against host effector cells, particularly the oxidative stress response, and in a mouse model of infection. Protein sequence analysis together with functional analysis of knockdown strains seem to suggest that PbSOD3 expression is linked with a pronounced extracellular activity while PbSOD1 seems more related to intracellular requirements of the fungus. Altogether, our data suggests that P. brasiliensis actively responds to the radicals generated endogenously during metabolism and counteracts the oxidative burst of immune cells by inducing the expression of SOD isoforms. PMID:26963091

  15. Identification and Analysis of the Role of Superoxide Dismutases Isoforms in the Pathogenesis of Paracoccidioides spp.

    Science.gov (United States)

    Tamayo, Diana; Muñoz, José F.; Lopez, Ángela; Urán, Martha; Herrera, Juan; Borges, Clayton L.; Restrepo, Ángela; Soares, Celia M.; Taborda, Carlos P.; Almeida, Agostinho J.; McEwen, Juan G.; Hernández, Orville

    2016-01-01

    The ability of Paracoccidioides to defend itself against reactive oxygen species (ROS) produced by host effector cells is a prerequisite to survive. To counteract these radicals, Paracoccidioides expresses, among different antioxidant enzymes, superoxide dismutases (SODs). In this study, we identified six SODs isoforms encoded by the Paracoccidioides genome. We determined gene expression levels of representative isolates of the phylogenetic lineages of Paracoccidioides spp. (S1, PS2, PS3 and Pb01-like) using quantitative RT-PCR. Assays were carried out to analyze SOD gene expression of yeast cells, mycelia cells, the mycelia-to-yeast transition and the yeast-to-mycelia germination, as well as under treatment with oxidative agents and during interaction with phagocytic cells. We observed an increased expression of PbSOD1 and PbSOD3 during the transition process, exposure to oxidative agents and interaction with phagocytic cells, suggesting that these proteins could assist in combating the superoxide radicals generated during the host-pathogen interaction. Using PbSOD1 and PbSOD3 knockdown strains we showed these genes are involved in the response of the fungus against host effector cells, particularly the oxidative stress response, and in a mouse model of infection. Protein sequence analysis together with functional analysis of knockdown strains seem to suggest that PbSOD3 expression is linked with a pronounced extracellular activity while PbSOD1 seems more related to intracellular requirements of the fungus. Altogether, our data suggests that P. brasiliensis actively responds to the radicals generated endogenously during metabolism and counteracts the oxidative burst of immune cells by inducing the expression of SOD isoforms. PMID:26963091

  16. Defects in Peroxisomal 6-Phosphogluconate Dehydrogenase Isoform PGD2 Prevent Gametophytic Interaction in Arabidopsis thaliana.

    Science.gov (United States)

    Hölscher, Christian; Lutterbey, Marie-Christin; Lansing, Hannes; Meyer, Tanja; Fischer, Kerstin; von Schaewen, Antje

    2016-05-01

    We studied the localization of 6-phosphogluconate dehydrogenase (PGD) isoforms of Arabidopsis (Arabidopsis thaliana). Similar polypeptide lengths of PGD1, PGD2, and PGD3 obscured which isoform may represent the cytosolic and/or plastidic enzyme plus whether PGD2 with a peroxisomal targeting motif also might target plastids. Reporter-fusion analyses in protoplasts revealed that, with a free N terminus, PGD1 and PGD3 accumulate in the cytosol and chloroplasts, whereas PGD2 remains in the cytosol. Mutagenesis of a conserved second ATG enhanced the plastidic localization of PGD1 and PGD3 but not PGD2. Amino-terminal deletions of PGD2 fusions with a free C terminus resulted in peroxisomal import after dimerization, and PGD2 could be immunodetected in purified peroxisomes. Repeated selfing of pgd2 transfer (T-)DNA alleles yielded no homozygous mutants, although siliques and seeds of heterozygous plants developed normally. Detailed analyses of the C-terminally truncated PGD2-1 protein showed that peroxisomal import and catalytic activity are abolished. Reciprocal backcrosses of pgd2-1 suggested that missing PGD activity in peroxisomes primarily affects the male gametophyte. Tetrad analyses in the quartet1-2 background revealed that pgd2-1 pollen is vital and in vitro germination normal, but pollen tube growth inside stylar tissues appeared less directed. Mutual gametophytic sterility was overcome by complementation with a genomic construct but not with a version lacking the first ATG. These analyses showed that peroxisomal PGD2 activity is required for guided growth of the male gametophytes and pollen tube-ovule interaction. Our report finally demonstrates an essential role of oxidative pentose-phosphate pathway reactions in peroxisomes, likely needed to sustain critical levels of nitric oxide and/or jasmonic acid, whose biosynthesis both depend on NADPH provision. PMID:26941195

  17. p150 ADAR1 isoform involved in maintenance of HeLa cell proliferation

    International Nuclear Information System (INIS)

    RNA-specific adenosine deaminase ADAR1 is ubiquitously expressed in a variety of mammalian cells and tissues. Although its physiological importance in non-nervous tissues has been confirmed by analysis of null mutation phenotypes, few endogenous editing substrates have been identified in numerous peripheral tissues and biological function of ADAR1 has not been fully understood. A conditional site-specific, ribozyme-based gene knock-down strategy was utilized to study the function of full-length isoform of ADAR1 (p150 protein) in HeLa cell. Double-stable HeLa cell lines were developed by transfecting HeLa Tet-On cells with a pTRE-derived plasmid that can express a hammerhead ribozyme against mRNA of p150 ADAR1 isoform under induction condition. Semi-quantitative RT-PCR and Western blotting were performed to measure the expression of p150 in selected cell clones. Cell proliferation was evaluated by means of MTT assay and growth curve analysis. Cellular morphological changes were observed under light microscope. Flow Cytometry was used for cell cycle analysis. Growth rate of cell transplants in BALB/c nude mice was also investigated. Both HeLa cell proliferation in vitro and the growth rate of transplanted HeLa cell-derived tumors in nude mice in vivo were significantly inhibited due to reduced expression of ADAR1 p150. Additionally, cell cycle analysis showed that cell progression from G1 phase to S phase was retarded in the ADAR1 p150 suppressed cells. Our results suggest that normal expression and functioning of p150 ADAR1 is essential for the maintenance of proper cell growth. The mechanisms underlying ADAR1's action might include both editing of currently unknown double-stranded RNAs and interacting with other cellular dsRNA-related processes

  18. MAP kinase pathways and calcitonin influence CD44 alternate isoform expression in prostate cancer cells

    International Nuclear Information System (INIS)

    Dysregulated expression and splicing of cell adhesion marker CD44 is found in many types of cancer. In prostate cancer (PC) specifically, the standard isoform (CD44s) has been found to be downregulated compared with benign tissue whereas predominant variant isoform CD44v7-10 is upregulated. Mitogen-activated protein kinase pathways and paracrine calcitonin are two common factors linked to dysregulated expression and splicing of CD44 in cancer. Calcitonin has been found to increase proliferation and invasion in PC acting through the protein kinase A pathway. In androgen-independent PC with known high CD44v7-10 expression, CD44 total and CD44v7-10 RNA or protein were assessed in response to exogenous and endogenous calcitonin and to inhibitors of protein kinase A, MEK, JNK, or p38 kinase. Benign cells and calcitonin receptor-negative PC cells were also tested. MEK or p38 but not JNK reduced CD44 total RNA by 40%–65% in cancer and benign cells. Inhibition of protein kinase A reduced CD44 total and v7-10 protein expression. In calcitonin receptor-positive cells only, calcitonin increased CD44 variant RNA and protein by 3 h and persisting to 48 h, apparently dependent on an uninhibited p38 pathway. Cells with constitutive CT expression showed an increase in CD44v7-10 mRNA but a decrease in CD44 total RNA. The MEK pathway increases CD44 RNA, while calcitonin, acting through the protein kinase A and p38 pathway, facilitates variant splicing. These findings could be used in the formulation of therapeutic methods for PC targeting CD44 alternate splicing

  19. Expression of CD150 in tumors of the central nervous system: identification of a novel isoform.

    Directory of Open Access Journals (Sweden)

    Olga Romanets-Korbut

    Full Text Available CD150 (IPO3/SLAM belongs to the SLAM family of receptors and serves as a major entry receptor for measles virus. CD150 is expressed on normal and malignant cells of the immune system. However, little is known about its expression outside the hematopoietic system, especially tumors of the central nervous system (CNS. Although CD150 was not found in different regions of normal brain tissues, our immunohistochemical study revealed its expression in 77.6% of human CNS tumors, including glioblastoma, anaplastic astrocytoma, diffuse astrocytoma, ependymoma, and others. CD150 was detected in the cytoplasm, but not on the cell surface of glioma cell lines, and it was colocalized with the endoplasmic reticulum and Golgi complex markers. In addition to the full length mRNA of the mCD150 splice isoform, in glioma cells we found a highly expressed novel CD150 transcript (nCD150, containing an 83 bp insert. The insert is derived from a previously unrecognized exon designated Cyt-new, which is located 510 bp downstream of the transmembrane region exon, and is a specific feature of primate SLAMF1. Both mCD150 and nCD150 cDNA variants did not contain any mutations and had the leader sequence. The nCD150 transcript was also detected in normal and malignant B lymphocytes, primary T cells, dendritic cells and macrophages; however, in glioma cells nCD150 was found to be the predominant CD150 isoform. Similarly to mCD150, cell surface expression of nCD150 allows wild type measles virus entry to the cell. Our data indicate that CD150 expression in CNS tumors can be considered a new diagnostic marker and potential target for novel therapeutic approaches.

  20. AMPK regulates circadian rhythms in a tissue- and isoform-specific manner.

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    Jee-Hyun Um

    Full Text Available BACKGROUND: AMP protein kinase (AMPK plays an important role in food intake and energy metabolism, which are synchronized to the light-dark cycle. In vitro, AMPK affects the circadian rhythm by regulating at least two clock components, CKIα and CRY1, via direct phosphorylation. However, it is not known whether the catalytic activity of AMPK actually regulates circadian rhythm in vivo. METHODOLOGY/PRINCIPAL FINDING: THE CATALYTIC SUBUNIT OF AMPK HAS TWO ISOFORMS: α1 and α2. We investigate the circadian rhythm of behavior, physiology and gene expression in AMPKα1-/- and AMPKα2-/- mice. We found that both α1-/- and α2-/- mice are able to maintain a circadian rhythm of activity in dark-dark (DD cycle, but α1-/- mice have a shorter circadian period whereas α2-/- mice showed a tendency toward a slightly longer circadian period. Furthermore, the circadian rhythm of body temperature was dampened in α1-/- mice, but not in α2-/- mice. The circadian pattern of core clock gene expression was severely disrupted in fat in α1-/- mice, but it was severely disrupted in the heart and skeletal muscle of α2-/- mice. Interestingly, other genes that showed circadian pattern of expression were dysreguated in both α1-/- and α2-/- mice. The circadian rhythm of nicotinamide phosphoryl-transferase (NAMPT activity, which converts nicotinamide (NAM to NAD+, is an important regulator of the circadian clock. We found that the NAMPT rhythm was absent in AMPK-deficient tissues and cells. CONCLUSION/SIGNIFICANCE: This study demonstrates that the catalytic activity of AMPK regulates circadian rhythm of behavior, energy metabolism and gene expression in isoform- and tissue-specific manners.

  1. Capillary Isoelectric Focusing of Akt Isoforms Identifies Highly Dynamic Phosphorylation in Neuronal Cells and Brain Tissue.

    Science.gov (United States)

    Schrötter, Sandra; Leondaritis, George; Eickholt, Britta J

    2016-05-01

    The PI3K/PTEN/Akt pathway has been established as a core signaling pathway that is crucial for the integration of neurons into neuronal circuits and the maintenance of the architecture and function of neurons in the adult brain. Akt1-3 kinases are specifically activated by two phosphorylation events on residues Thr(308) and Ser(473) upon growth factor signaling, which subsequently phosphorylate a vast cohort of downstream targets. However, we still lack a clear understanding of the complexity and regulation of isoform specificity within the PI3K/PTEN/Akt pathway. We utilized a capillary-based isoelectric focusing method to study dynamics of Akt phosphorylation in neuronal cells and the developing brain and identify previously undescribed features of Akt phosphorylation and activation. First, we show that the accumulation of multiple phosphorylation events on Akt forms occur concurrently with Ser(473) and Thr(308) phosphorylation upon acute PI3K activation and provide evidence for uncoupling of Ser(473) and Thr(308) phosphorylation, as well as differential sensitivities of Akt1 forms upon PI3K inhibition. Second, we detect a transient shift in Akt isoform phosphorylation and activation pattern during early postnatal brain development, at stages corresponding to synapse development and maturation. Third, we show differential sensitivities of Ser(473)-Akt species to PTEN deletion in mature neurons, which suggests inherent differences in the Akt pools that are accessible to growth factors as compared with the pools that are controlled by PTEN. Our study demonstrates the presence of complex phosphorylation events of Akt in a time- and signal-dependent manner in neurons. PMID:26945062

  2. Plasma proteome changes in cardiovascular disease patients: novel isoforms of apolipoprotein A1

    Directory of Open Access Journals (Sweden)

    Oravec Milan

    2011-06-01

    Full Text Available Abstract Background The aim of this proteomic study was to look for changes taking place in plasma proteomes of patients with acute myocardial infarction (AMI, unstable angina pectoris (UAP, and stable angina pectoris (SAP. Methods Depleted plasma proteins were separated by 2D SDS-PAGE (pI 4-7, and proteomes were compared using Progenesis SameSpots statistical software. Proteins were identified by nanoLC-MS/MS. Proteins were quantified using commercial kits. Apolipoprotein A1 was studied using 1D and 2D SDS-PAGE, together with western blotting. Results Reciprocal comparison revealed 46 unique, significantly different spots; proteins in 34 spots were successfully identified and corresponded to 38 different proteins. Discrete comparisons of patient groups showed 45, 41, and 8 significantly different spots when AMI, UAP, and SAP were compared with the control group. On the basis of our proteomic data, plasma levels of two of them, alpha-1 microglobulin and vitamin D-binding protein, were determined. The data, however, failed to prove the proteins to be suitable markers or risk factors in the studied groups. The plasma level and isoform representation of apolipoprotein A1 were also estimated. Using 1D and 2D SDS-PAGE, together with western blotting, we observed extra high-molecular weight apolipoprotein A1 fractions presented only in the patient groups, indicating that the novel high-molecular weight isoforms of apolipoprotein A1 may be potential new markers or possible risk factors of cardiovascular disease. Conclusion The reported data show plasma proteome changes in patients with AMI, UAP, and SAP. We propose some apolipoprotein A1 fractions as a possible new disease-associated marker of cardiovascular disorders.

  3. Analysis of tarantula skeletal muscle protein sequences and identification of transcriptional isoforms

    Directory of Open Access Journals (Sweden)

    Yu Jun

    2009-03-01

    Full Text Available Abstract Background Tarantula has been used as a model system for studying skeletal muscle structure and function, yet data on the genes expressed in tarantula muscle are lacking. Results We constructed a cDNA library from Aphonopelma sp. (Tarantula skeletal muscle and got 2507 high-quality 5'ESTs (expressed sequence tags from randomly picked clones. EST analysis showed 305 unigenes, among which 81 had more than 2 ESTs. Twenty abundant unigenes had matches to skeletal muscle-related genes including actin, myosin, tropomyosin, troponin-I, T and C, paramyosin, muscle LIM protein, muscle protein 20, a-actinin and tandem Ig/Fn motifs (found in giant sarcomere-related proteins. Matches to myosin light chain kinase and calponin were also identified. These results support the existence of both actin-linked and myosin-linked regulation in tarantula skeletal muscle. We have predicted full-length as well as partial cDNA sequences both experimentally and computationally for myosin heavy and light chains, actin, tropomyosin, and troponin-I, T and C, and have deduced the putative peptides. A preliminary analysis of the structural and functional properties was also carried out. Sequence similarities suggested multiple isoforms of most myofibrillar proteins, supporting the generality of multiple isoforms known from previous muscle sequence studies. This may be related to a mix of muscle fiber types. Conclusion The present study serves as a basis for defining the transcriptome of tarantula skeletal muscle, for future in vitro expression of tarantula proteins, and for interpreting structural and functional observations in this model species.

  4. Isoform-specific localization of Nogo protein in the optic pathway of mouse embryos.

    Science.gov (United States)

    Wang, Liqing; Wang, Jun; Ma, Ding; Taylor, Jeremy S H; Chan, Sun-On

    2016-08-01

    Expression of Nogo protein was investigated in the optic pathway of embryonic mice by using isoform-specific antibodies Bianca and 11C7, which recognize Nogo-A/B and Nogo-A, respectively. Our previous reports from using antibody N18 have shown that Nogo is localized on the radial glia in the retina and at the midline of the ventral diencephalon in mouse embryos during the ingrowth of retinal ganglion cells (RGCs) axons. This glial-specific localization is markedly different from findings in other studies. This study showed Nogo-A/B primarily on radial glia in the retina at E13 and then later on retinal ganglion cells and axons at E14 and E15, whereas Nogo-A was expressed preferentially by RGCs and their axons. In the ventral diencephalon, Nogo-A/B was expressed strongly on radial glia, particularly in those located in the midline region of the chiasm but also on RGC axons. In Nogo-A knockout embryos, the isoform Nogo-B (revealed by Bianca) was observed on radial glia in the ventral diencephalon and on RGCs and their axons. We concluded that Nogo-A is localized on the ganglion cells and retinal axons, whereas Nogo-B is expressed by the radial glia in the optic pathway. Nogo-B may play an important role in guiding axon growth in decisive regions of the visual pathway, which include the optic disc and the optic chiasm. J. Comp. Neurol. 524:2322-2334, 2016. © 2016 Wiley Periodicals, Inc. PMID:26718118

  5. The β isoform of GSK3 mediates podocyte autonomous injury in proteinuric glomerulopathy.

    Science.gov (United States)

    Li, Changbin; Ge, Yan; Dworkin, Lance; Peng, Ai; Gong, Rujun

    2016-05-01

    Converging evidence points to glycogen synthase kinase (GSK) 3 as a key player in the pathogenesis of podocytopathy and proteinuria. However, it remains unclear if GSK3 is involved in podocyte autonomous injury in glomerular disease. In normal kidneys, the β isoform of GSK3 was found to be the major GSK3 expressed in glomeruli and intensely stained in podocytes. GSK3β expression in podocytes was markedly elevated in experimental or human proteinuric glomerulopathy. Podocyte-specific somatic ablation of GSK3β in adult mice attenuated proteinuria and ameliorated podocyte injury and glomerular damage in experimental adriamycin (ADR) nephropathy. Mechanistically, actin cytoskeleton integrity in podocytes was largely preserved in GSK3β knockout mice following ADR insult, concomitant with a correction of podocyte hypermotility and lessened phosphorylation and activation of paxillin, a focal adhesion-associated adaptor protein. In addition, GSK3β knockout diminished ADR-induced NFκB RelA/p65 phosphorylation selectively at serine 467; suppressed de novo expression by podocytes of NFκB-dependent podocytopathic mediators, including B7-1, cathepsin L, and MCP-1; but barely affected the induction of NFκB target pro-survival factors, such as Bcl-xL. Moreover, the ADR-elicited podocytopenia and podocyte death were significantly attenuated in GSK3β knockout mice, associated with protection against podocyte mitochondrial damage and reduced phosphorylation and activation of cyclophilin F, a structural component of mitochondria permeability transition pores. Overall, our findings suggest that the β isoform of GSK3 mediates autonomous podocyte injury in glomerulopathy by integrating multiple podocytopathic signalling pathways. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. PMID:26876299

  6. Impact of resistance exercise during bed rest on skeletal muscle sarcopenia and myosin isoform distribution

    Science.gov (United States)

    Bamman, M. M.; Clarke, M. S.; Feeback, D. L.; Talmadge, R. J.; Stevens, B. R.; Lieberman, S. A.; Greenisen, M. C.

    1998-01-01

    Because resistance exercise (REx) and bed-rest unloading (BRU) are associated with opposing adaptations, our purpose was to test the efficacy of REx against the effects of 14 days of BRU on the knee-extensor muscle group. Sixteen healthy men were randomly assigned to no exercise (NoEx; n = 8) or REx (n = 8). REx performed five sets of leg press exercise with 80-85% of one repetition maximum (1 RM) every other day during BRU. Muscle samples were removed from the vastus lateralis muscle by percutaneous needle biopsy. Myofiber distribution was determined immunohistochemically with three monoclonal antibodies against myosin heavy chain (MHC) isoforms (I, IIa, IIx). MHC distribution was further assessed by quantitative gel electrophoresis. Dynamic 1-RM leg press and unilateral maximum voluntary isometric contraction (MVC) were determined. Maximal neural activation (root mean squared electromyogram) and rate of torque development (RTD) were measured during MVC. Reductions (P < 0.05) in type I (15%) and type II (17%) myofiber cross-sectional areas were found in NoEx but not in REx. Electrophoresis revealed no changes in MHC isoform distribution. The percentage of type IIx myofibers decreased (P < 0.05) in REx from 9 to 2% and did not change in NoEx. 1 RM was reduced (P < 0.05) by 9% in NoEx but was unchanged in REx. MVC fell by 15 and 13% in NoEx and REx, respectively. The agonist-to-antagonist root mean squared electromyogram ratio decreased (P < 0.05) 19% in REx. RTD slowed (P < 0.05) by 54% in NoEx only. Results indicate that REx prevented BRU-induced myofiber atrophy and also maintained training-specific strength. Unlike spaceflight, BRU did not induce shifts in myosin phenotype. The reported benefits of REx may prove useful in prescribing exercise for astronauts in microgravity.

  7. Concordant and discordant regulation of target genes by miR-31 and its isoforms.

    Directory of Open Access Journals (Sweden)

    Yu-Tzu Chan

    Full Text Available It has been shown that imprecise cleavage of a primary or precursor RNA by Drosha or Dicer, respectively, may yield a group of microRNA (miRNA variants designated as "isomiR". Variations in the relative abundance of isoforms for a given miRNA among different species and different cell types beg the question whether these isomiRs might regulate target genes differentially. We compared the capacity of three miR-31 isoforms (miR-31-H, miR-31-P, and miR-31-M, which differ only slightly in their 5'- and/or 3'-end sequences, to regulate several known targets and a predicted target, Dicer. Notably, we found isomiR-31s displayed concordant and discordant regulation of 6 known target genes. Furthermore, we validated a predicted target gene, Dicer, to be a novel target of miR-31 but only miR-31-P could directly repress Dicer expression in both MCF-7 breast cancer cells and A549 lung cancer cells, resulting in their enhanced sensitivity to cisplatin, a known attribute of Dicer knockdown. This was further supported by reporter assay using full length 3'-untranslated region (UTR of Dicer. Our findings not only revealed Dicer to be a direct target of miR-31, but also demonstrated that isomiRs displayed similar and disparate regulation of target genes in cell-based systems. Coupled with the variations in the distribution of isomiRs among different cells or conditions, our findings support the possibility of fine-tuning gene expression by miRNAs.

  8. The three isoforms of the light-harvesting complex II Spectroscopic features, trimer formation, and functional roles

    CERN Document Server

    Standfuss, Jorg

    2004-01-01

    The major light-harvesting complex (LHC-II) of higher plants plays a crucial role in capturing light energy for photosynthesis and in regulating the flow of energy within the photosynthetic apparatus. Native LHC-II isolated from plant tissue consists of three isoforms, Lhcb1, Lhcb2, and Lhcb3, which form homo- and heterotrimers. All three isoforms are highly conserved among different species, suggesting distinct functional roles. We produced the three LHC-II isoforms by heterologous expression of the polypeptide in Escherichia coli and in vitro refolding with purified pigments. Although Lhcb1 and Lhcb2 are very similar in polypeptide sequence and pigment content, Lhcb3 is clearly different because it lacks an N-terminal phosphorylation site and has a higher chlorophyll a/b ratio, suggesting the absence of one chlorophyll b. Low temperature absorption and fluorescence emission spectra of the pure isoforms revealed small but significant differences in pigment organization. The oligomeric state of the pure isofo...

  9. A real-time PCR method for the quantification of the two isoforms of metallothionein in Lake Trout (Salvelinus namaycush).

    Science.gov (United States)

    Werner, Julieta; Palace, Vince; Baron, Christopher; Shiu, Robert; Yarmill, Alison

    2008-01-01

    Metallothioneins (MTs) are low-molecular-weight proteins whose physiologic roles are the regulation of essential metals Cu and Zn, sequestration of heavy metals, and free radical scavenging. Induced production of MTs in a wide variety of organisms exposed to heavy metals has made them popular exposure indicators. While it has been postulated that the three different isoforms of MT play different physiologic roles, methods to discern induction separately have not been available. The development of real-time polymerase chain reaction (real-time PCR) primers and TaqMan probes to measure the two MT isoforms found in salmonid fish are described. Assuming a high degree of homology between the isoforms and within different groups of salmonids, the sequences for MT-I and MT-II from rainbow trout were used to develop primers and probes for lake trout using the Primer3 program. Two sections of each isoform that varied by only a few nucleotides were targeted. SYBR Green validated the primer specificity, and melt curve analysis further ensured that only one product was amplified. Analysis of archived samples from fish captured in unmanipulated reference lakes or from lakes experimentally treated with cadmium or ethynylestradiol (EE2) afforded an examination of seasonal and contaminant influences on MT-I and MT-II mRNA expression. PMID:17687585

  10. Early detection of skeletal muscle injury by assay of creatine kinase MM isoforms in serum after acute exercise

    DEFF Research Database (Denmark)

    Apple, F. S.; Hellsten, Ylva; Clarkson, P. M.

    1988-01-01

    We could detect skeletal muscle injury early after an acute exercise bout by measuring creatine kinase (CK, EC 2.7.3.2) MM isoforms in serum. Eleven men performed 120 alternating-arm, eccentric (muscle lengthening) biceps contractions with the intensity of each contraction being 110% of maximal...

  11. Design, synthesis, and structure-activity analysis of isoform-selective retinoic acid receptor ß ligands

    DEFF Research Database (Denmark)

    Lund, Birgitte W.; Knapp, Anne Eeg; Piu, Fabrice;

    2009-01-01

    We recently discovered the isoform selective RAR beta 2 ligand 4'-octyl-4-biphenylcarboxylic acid (3, AC-55649). Although 3 is highly potent at RAR beta 2 and displays excellent selectivity, solubility issues make it unsuitable for drug development. Herein we describe the exploration of the SAR in...

  12. Opposing roles of the two isoforms of ErbB3 binding protein 1 in human cancer cells.

    Science.gov (United States)

    Ko, Hyo Rim; Chang, Yun Sil; Park, Won Soon; Ahn, Jee-Yin

    2016-09-15

    The different functions of the two isoforms of ErbB3 binding protein 1 (Ebp1), p48 and p42, have recently become the focus of interest as they reveal contradictory roles in cell growth promoting ability. The conformational change that crystal structure of p42 was shown to lack α helices at the amino-terminus present in p48 represents the differential binding partners and protein modifications of two Ebp1 isoforms. N-terminal specific phosphorylation by CDK2 and deregulation of the p53 tumor suppressor through specific interaction with HDM2 and Akt activation is postulated to contribute to p48-mediated tumorigenesis. The short isoform p42 Ebp1, which is actual binding partner of ErbB3 has been implicated as a tumor suppressor with many binding partners such as Rb, HDAC2, Sin3A and the p85 subunit of PI3K with HSP70/CHIP, inhibiting its own antiproliferative activity or inhibiting PI3K activity. The aim of the current review is to provide a summary on distinctive cellular functions of two Ebp1 proteins and their molecular partners that might be responsible for the unique functions of each isoform of Ebp1. PMID:27130196

  13. [Isoforms of the human histamine H3 receptor: Generation, expression in the central nervous system and functional implications].

    Science.gov (United States)

    García-Gálvez, Ana Maricela; Arias-Montaño, José Antonio

    2016-01-01

    Histamine plays a significant role as a neuromodulator in the human central nervous system. Histamine-releasing neurons are exclusively located in the tuberomammillary nucleus of the hypothalamus, project to all major areas of the brain, and participate in functions such as the regulation of sleep/wakefulness, locomotor activity, feeding and drinking, analgesia, learning, and memory. The functional effects of histamine are exerted through the activation of four G protein-coupled receptors (H1, H2, H3 and H4), and in the central nervous system the first three receptors are widely expressed. The H3 receptor (H3R) is found exclusively in neuronal cells, where it functions as auto- and hetero-receptor. One remarkable characteristic of the H3R is the existence of isoforms, generated by alternative splicing of the messenger RNA. For the human H3R, 20 isoforms have been reported; although a significant number lack those regions required for agonist binding or receptor signaling, at least five isoforms appear functional upon heterologous expression. In this work we review the evidence for the generation of human H3R isoforms, their expression, and the available information regarding the functionality of such receptors. PMID:26927649

  14. Ulipristal Acetate Inhibits Progesterone Receptor Isoform A-Mediated Human Breast Cancer Proliferation and BCl2-L1 Expression.

    Directory of Open Access Journals (Sweden)

    Nathalie Esber

    Full Text Available The progesterone receptor (PR with its isoforms and ligands are involved in breast tumorigenesis and prognosis. We aimed at analyzing the respective contribution of PR isoforms, PRA and PRB, in breast cancer cell proliferation in a new estrogen-independent cell based-model, allowing independent PR isoforms analysis. We used the bi-inducible human breast cancer cell system MDA-iPRAB. We studied the effects and molecular mechanisms of action of progesterone (P4 and ulipristal acetate (UPA, a new selective progesterone receptor modulator, alone or in combination. P4 significantly stimulated MDA-iPRA expressing cells proliferation. This was associated with P4-stimulated expression of the anti-apoptotic factor BCL2-L1 and enhanced recruitment of PRA, SRC-1 and RNA Pol II onto the +58 kb PR binding motif of the BCL2-L1 gene. UPA decreased cell proliferation and repressed BCL2-L1 expression in the presence of PRA, correlating with PRA and SRC1 but not RNA Pol II recruitment. These results bring new information on the mechanism of action of PR ligands in controlling breast cancer cell proliferation through PRA in an estrogen independent model. Evaluation of PR isoforms ratio, as well as molecular signature studies based on PRA target genes could be proposed to facilitate personalized breast cancer therapy. In this context, UPA could be of interest in endocrine therapy. Further confirmation in the clinical setting is required.

  15. Ulipristal Acetate Inhibits Progesterone Receptor Isoform A-Mediated Human Breast Cancer Proliferation and BCl2-L1 Expression.

    Science.gov (United States)

    Esber, Nathalie; Le Billan, Florian; Resche-Rigon, Michèle; Loosfelt, Hugues; Lombès, Marc; Chabbert-Buffet, Nathalie

    2015-01-01

    The progesterone receptor (PR) with its isoforms and ligands are involved in breast tumorigenesis and prognosis. We aimed at analyzing the respective contribution of PR isoforms, PRA and PRB, in breast cancer cell proliferation in a new estrogen-independent cell based-model, allowing independent PR isoforms analysis. We used the bi-inducible human breast cancer cell system MDA-iPRAB. We studied the effects and molecular mechanisms of action of progesterone (P4) and ulipristal acetate (UPA), a new selective progesterone receptor modulator, alone or in combination. P4 significantly stimulated MDA-iPRA expressing cells proliferation. This was associated with P4-stimulated expression of the anti-apoptotic factor BCL2-L1 and enhanced recruitment of PRA, SRC-1 and RNA Pol II onto the +58 kb PR binding motif of the BCL2-L1 gene. UPA decreased cell proliferation and repressed BCL2-L1 expression in the presence of PRA, correlating with PRA and SRC1 but not RNA Pol II recruitment. These results bring new information on the mechanism of action of PR ligands in controlling breast cancer cell proliferation through PRA in an estrogen independent model. Evaluation of PR isoforms ratio, as well as molecular signature studies based on PRA target genes could be proposed to facilitate personalized breast cancer therapy. In this context, UPA could be of interest in endocrine therapy. Further confirmation in the clinical setting is required. PMID:26474308

  16. Two new isoforms of the human hepatoma-derived growth factor interact with components of the cytoskeleton.

    Science.gov (United States)

    Nüße, Jessica; Mirastschijski, Ursula; Waespy, Mario; Oetjen, Janina; Brandes, Nadine; Rebello, Osmond; Paroni, Federico; Kelm, Sørge; Dietz, Frank

    2016-05-01

    Hepatoma-derived growth factor (HDGF) is involved in diverse, apparently unrelated processes, such as cell proliferation, apoptosis, DNA-repair, transcriptional control, ribosome biogenesis and cell migration. Most of the interactions of HDGF with diverse molecules has been assigned to the hath region of HDGF. In this study we describe two previously unknown HDGF isoforms, HDGF-B and HDGF-C, generated via alternative splicing with structurally unrelated N-terminal regions of their hath region, which is clearly different from the well described isoform, HDGF-A. In silico modeling revealed striking differences near the PHWP motif, an essential part of the binding site for glycosaminoglycans and DNA/RNA. This observation prompted the hypothesis that these isoforms would have distinct interaction patterns with correspondingly diverse roles on cellular processes. Indeed, we discovered specific associations of HDGF-B and HDGF-C with cytoskeleton elements, such as tubulin and dynein, suggesting previously unknown functions of HDGF in retrograde transport, site directed localization and/or cytoskeleton organization. In contrast, the main isoform HDGF-A does not interact directly with the cytoskeleton, but via RNA with messenger ribonucleoprotein (mRNP) complexes. In summary, the discovery of HDGF splice variants with their discrete binding activities and subcellular distributions opened new avenues for understanding its biological function and importance. PMID:26845719

  17. Glutamate dehydrogenase isoforms with N-terminal (His)6- or FLAG-tag retain their kinetic properties and cellular localization

    DEFF Research Database (Denmark)

    Pajęcka, Kamilla; Nielsen, Camilla Wendel; Hauge, Anne;

    2014-01-01

    Glutamate dehydrogenase (GDH) is a crucial enzyme on the crossroads of amino acid and energy metabolism and it is operating in all domains of life. According to current knowledge GDH is present only in one functional isoform in most animals, including mice. In addition to this housekeeping enzyme...

  18. PUTATIVE CREATINE KINASE M-ISOFORM IN HUMAN SPERM IS IDENTIFIED AS THE 70-KILODALTON HEAT SHOCK PROTEIN HSPA2

    Science.gov (United States)

    THE PUTATIVE CREATINE KINASE M-ISOFORM IN HUMAN SPERM IS IDENTIFIED AS THE 70 kDa HEAT SHOCK PROTEIN HSPA2* Gabor Huszar1, Kathryn Stone2, David Dix3 and Lynne Vigue11The Sperm Physiology Laboratory, Department of Obstetrics and Gynecology, 2 W.M. Keck Foundatio...

  19. Na(+)-K(+)-ATPase alpha(2)-isoform expression in guinea pig hearts during transition from compensation to decompensation.

    Science.gov (United States)

    Trouve, P; Carre, F; Belikova, I; Leclercq, C; Dakhli, T; Soufir, L; Coquard, I; Ramirez-Gil, J; Charlemagne, D

    2000-10-01

    Disturbance in ionic gradient across sarcolemma may lead to arrhythmias. Because Na(+)-K(+)-ATPase regulates intracellular Na(+) and K(+) concentrations, and therefore intracellular Ca(2+) concentration homeostasis, our aim was to determine whether changes in the Na(+)-K(+)-ATPase alpha-isoforms in guinea pigs during transition from compensated (CLVH) to decompensated left ventricular hypertrophy (DLVH) were concomitant with arrhythmias. After 12- and 20-mo aortic stenosis, CLVH and DLVH were characterized by increased mean arterial pressure (30% and 52.7%, respectively). DLVH differed from CLVH by significantly increased end-diastolic pressure (34%), decreased sarco(endo)plasmic reticulum Ca(2+)-ATPase (-75%), and increased Na(+)/Ca(2+) exchanger (25%) mRNA levels and by the occurrence of ventricular arrhythmias. The alpha-isoform (mRNA and protein levels) was significantly lower in DLVH (2.2 +/- 0.2- and 1. 4 +/- 0.15-fold, respectively, vs. control) than in CLVH (3.5 +/- 0. 4- and 2.2 +/- 0.13-fold, respectively) and was present in sarcolemma and T tubules. Changes in the levels of alpha(1)- and alpha(3)-isoform in CLVH and DLVH appear physiologically irrelevant. We suggest that the increased level of alpha(2)-isoform in CLVH may participate in compensation, whereas its relative decrease in DLVH may enhance decompensation and arrhythmias. PMID:11009487

  20. Multiple Promoters in the WNK1 Gene: One Controls Expression of a Kidney-Specific Kinase-Defective Isoform

    Science.gov (United States)

    Delaloy, Celine; Lu, Jingyu; Houot, Anne-Marie; Disse-Nicodeme, Sandra; Gasc, Jean-Marie; Corvol, Pierre; Jeunemaitre, Xavier

    2003-01-01

    WNK1 is a serine-threonine kinase, the expression of which is affected in pseudohypoaldosteronism type II, a Mendelian form of arterial hypertension. We characterized human WNK1 transcripts to determine the molecular mechanisms governing WNK1 expression. We report the presence of two promoters generating two WNK1 isoforms with a complete kinase domain. Further variations are achieved by the use of two polyadenylation sites and tissue-specific splicing. We also determined the structure of a kidney-specific isoform regulated by a third promoter and starting at a novel exon. This transcript is kinase defective and has a predominant expression in the kidney compared to the other WNK1 isoforms, with, furthermore, a highly restricted expression profile in the distal convoluted tubule. We confirmed that the ubiquitous and kidney-specific promoters are functional in several cells lines and identified core promoters and regulatory elements. In particular, a strong enhancer element upstream from the kidney-specific exon seems specific to renal epithelial cells. Thus, control of human WNK1 gene expression of kinase-active or -deficient isoforms is mediated predominantly through the use of multiple transcription initiation sites and tissue-specific regulatory elements. PMID:14645531

  1. Different BAG-1 isoforms have distinct functions in modulating chemotherapeutic-induced apoptosis in breast cancer cells

    Institute of Scientific and Technical Information of China (English)

    Hongyu LIU; Zhuomin WANG; Yun BAI; Min WANG; Ying LI; Sen WEI; Qinghua ZHOU; Jun CHEN

    2009-01-01

    Aim:BAG-1 is a multifunctional anti-apoptotic gene with four isoforms,and different BAG-1 isoforms have different anti-apoptotic functions.In this study,we transfected BAG-1 isoforms into the human breast cancer cell lines Hs578T (ER nega-tive) and MCF-7 (ER positive) to study their effect on apoptosis with or without estrogens.Methods: The constructed recombinant expression vectors carrying individual BAG-1 isoforms was used to transfect human breast cancer cell lines Hs578T (ER negative) and MCF-7 (ER positive).After stable cell lines were made,a variety of apoptosis-inducing agents,including doxorubicin,docetaxel,and 5-FU,was used to treat these cell lines with or without estrogen to test the role of BAG-1.The mechanism by which BAG-1 affected the function of Bcl-2 was exploredby using the cycloheximide chase assay.Results: The BAG-1 p50 and p46 isoforms significantly enhanced the resistance to apoptosis in both cell lines according to flow cytometry analysis.BAG-1 p33 and p29 failed to protect the transfected cells from apoptosis.The cell viability assay showed that only BAG-1 p50,but not p46,p33,or p29,increased estrogen-dependent function in ER-positive cell line MCF-7.Only BAG-1 p50 dramatically increased its anti-apoptotic ability in the presence of estrogen,while estrogen has very little effect on the anti-apoptotic ability of other BAG-1 isoforms.In the detection of the expression of K-ras,Hsp70,cytochrome c,Raf-1,ER-α,and Bcl-2 in MCF-7 cells by Western blot,only Bcl-2 protein expression was significantly increased in MCF-7 cells transfected with BAG-1 p50 and p46,respectively.Furthermore,the cycloheximide chase assay indicated that the degradation of Bcl-2 protein was extended in the BAG-1 p50 and p46 transfected MCF-7 cells.Conclusion: Distinct isoforrns of BAG-1 have different anti-apoptotic functions in breast cancer cells,and that the BAG-1 p50 isoform can potentiate the role of estrogen in ER-positive breast cancer.

  2. Wnt isoform-specific interactions with coreceptor specify inhibition or potentiation of signaling by LRP6 antibodies.

    Science.gov (United States)

    Gong, Yan; Bourhis, Eric; Chiu, Cecilia; Stawicki, Scott; DeAlmeida, Venita I; Liu, Bob Y; Phamluong, Khanhky; Cao, Tim C; Carano, Richard A D; Ernst, James A; Solloway, Mark; Rubinfeld, Bonnee; Hannoush, Rami N; Wu, Yan; Polakis, Paul; Costa, Mike

    2010-01-01

    β-Catenin-dependent Wnt signaling is initiated as Wnt binds to both the receptor FZD and coreceptor LRP5/6, which then assembles a multimeric complex at the cytoplasmic membrane face to recruit and inactivate the kinase GSK3. The large number and sequence diversity of Wnt isoforms suggest the possibility of domain-specific ligand-coreceptor interactions, and distinct binding sites on LRP6 for Wnt3a and Wnt9b have recently been identified in vitro. Whether mechanistically different interactions between Wnts and coreceptors might mediate signaling remains to be determined. It is also not clear whether coreceptor homodimerization induced extracellularly can activate Wnt signaling, as is the case for receptor tyrosine kinases. We generated monoclonal antibodies against LRP6 with the unexpected ability to inhibit signaling by some Wnt isoforms and potentiate signaling by other isoforms. In cell culture, two antibodies characterized further show reciprocal activities on most Wnts, with one antibody antagonizing and the other potentiating. We demonstrate that these antibodies bind to different regions of LRP6 protein, and inhibition of signaling results from blocking Wnt binding. Antibody-mediated dimerization of LRP6 can potentiate signaling only when a Wnt isoform is also able to bind the complex, presumably recruiting FZD. Endogenous autocrine Wnt signaling in different tumor cell lines can be either antagonized or enhanced by the LRP6 antibodies, indicating expression of different Wnt isoforms. As anticipated from the roles of Wnt signaling in cancer and bone development, antibody activities can also be observed in mice for inhibition of tumor growth and in organ culture for enhancement of bone mineral density. Collectively, our results indicate that separate binding sites for different subsets of Wnt isoforms determine the inhibition or potentiation of signaling conferred by LRP6 antibodies. This complexity of coreceptor-ligand interactions may allow for

  3. Identification of ryanodine receptor isoforms in prostate DU-145, LNCaP, and PWR-1E cells.

    Science.gov (United States)

    Kobylewski, Sarah E; Henderson, Kimberly A; Eckhert, Curtis D

    2012-08-24

    The ryanodine receptor (RyR) is a large, intracellular calcium (Ca(2+)) channel that is associated with several accessory proteins and is an important component of a cell's ability to respond to changes in the environment. Three isoforms of the RyR exist and are well documented for skeletal and cardiac muscle and the brain, but the isoforms in non-excitable cells are poorly understood. The aggressiveness of breast cancers in women has been positively correlated with the expression of the RyR in breast tumor tissue, but it is unknown if this is limited to specific isoforms. Identification and characterization of RyRs in cancer models is important in understanding the role of the RyR channel complex in cancer and as a potential therapeutic target. The objective of this report was to identify the RyR isoforms expressed in widely used prostate cancer cell lines, DU-145 and LNCaP, and the non-tumorigenic prostate cell line, PWR-1E. Oligonucleotide primers specific for each isoform were used in semi-quantitative and real-time PCR to determine the identification and expression levels of the RyR isoforms. RyR1 was expressed in the highest amount in DU-145 tumor cells, expression was 0.48-fold in the non-tumor cell line PWR-1E compared to DU-145 cells, and no expression was observed in LNCaP tumor cells. DU-145 cells had the lowest expression of RyR2. The expression was 26- and 15-fold higher in LNCaP and PWR-1E cells, respectively. RyR3 expression was not observed in any of the cell lines. All cell types released Ca(2+) in response to caffeine showing they had functional RyRs. Total cellular RyR-associated Ca(2+) release is determined by both the number of activated RyRs and its accessory proteins which modulate the receptor. Our results suggest that the correlation between the expression of the RyR and tumor aggression is not related to specific RyR isoforms, but may be related to the activity and number of receptors. PMID:22846571

  4. Estradiol differentially induces progesterone receptor isoforms expression through alternative promoter regulation in a mouse embryonic hypothalamic cell line.

    Science.gov (United States)

    Vázquez-Martínez, Edgar Ricardo; Camacho-Arroyo, Ignacio; Zarain-Herzberg, Angel; Rodríguez, María Carmen; Mendoza-Garcés, Luciano; Ostrosky-Wegman, Patricia; Cerbón, Marco

    2016-06-01

    Progesterone receptor (PR) presents two main isoforms (PR-A and PR-B) that are regulated by two specific promoters and transcribed from alternative transcriptional start sites. The molecular regulation of PR isoforms expression in embryonic hypothalamus is poorly understood. The aim of the present study was to assess estradiol regulation of PR isoforms in a mouse embryonic hypothalamic cell line (mHypoE-N42), as well as the transcriptional status of their promoters. MHypoE-N42 cells were treated with estradiol for 6 and 12 h. Then, Western blot, real-time quantitative reverse transcription polymerase chain reaction, and chromatin and DNA immunoprecipitation experiments were performed. PR-B expression was transiently induced by estradiol after 6 h of treatment in an estrogen receptor alpha (ERα)-dependent manner. This induction was associated with an increase in ERα phosphorylation (serine 118) and its recruitment to PR-B promoter. After 12 h of estradiol exposure, a downregulation of this PR isoform was associated with a decrease of specific protein 1, histone 3 lysine 4 trimethylation, and RNA polymerase II occupancy on PR-B promoter, without changes in DNA methylation and hydroxymethylation. In contrast, there were no estradiol-dependent changes in PR-A expression that could be related with the epigenetic marks or the transcription factors evaluated. We demonstrate that PR isoforms are differentially regulated by estradiol and that the induction of PR-B expression is associated to specific transcription factors interactions and epigenetic changes in its promoter in embryonic hypothalamic cells. PMID:26676302

  5. Charged residues distribution modulates selectivity of the open state of human isoforms of the voltage dependent anion-selective channel.

    Science.gov (United States)

    Amodeo, Giuseppe Federico; Scorciapino, Mariano Andrea; Messina, Angela; De Pinto, Vito; Ceccarelli, Matteo

    2014-01-01

    Voltage Dependent Anion-selective Channels (VDACs) are pore-forming proteins located in the outer mitochondrial membrane. They are responsible for the access of ions and energetic metabolites into the inner membrane transport systems. Three VDAC isoforms exist in mammalian, but their specific role is unknown. In this work we have performed extensive (overall ∼5 µs) Molecular Dynamics (MD) simulations of the human VDAC isoforms to detect structural and conformational variations among them, possibly related to specific functional roles of these proteins. Secondary structure analysis of the N-terminal domain shows a high similarity among the three human isoforms of VDAC but with a different plasticity. In particular, the N-terminal domain of the hVDAC1 is characterized by a higher plasticity, with a ∼20% occurrence for the 'unstructured' conformation throughout the folded segment, while hVDAC2, containing a peculiar extension of 11 amino acids at the N-terminal end, presents an additional 310-helical folded portion comprising residues 10' to 3, adhering to the barrel wall. The N-terminal sequences of hVDAC isoforms are predicted to have a low flexibility, with possible consequences in the dynamics of the human VDACs. Clear differences were found between hVDAC1 and hVDAC3 against hVDAC2: a significantly modified dynamics with possible important consequence on the voltage-gating mechanism. Charge distribution inside and at the mouth of the pore is responsible for a different preferential localization of ions with opposite charge and provide a valuable rationale for hVDAC1 and hVDAC3 having a Cl-/K+ selectivity ratio of 1.8, whereas hVDAC2 of 1.4. Our conclusion is that hVDAC isoforms, despite sharing a similar scaffold, have modified working features and a biological work is now requested to give evidence to the described dissimilarities. PMID:25084457

  6. Charged residues distribution modulates selectivity of the open state of human isoforms of the voltage dependent anion-selective channel.

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    Giuseppe Federico Amodeo

    Full Text Available Voltage Dependent Anion-selective Channels (VDACs are pore-forming proteins located in the outer mitochondrial membrane. They are responsible for the access of ions and energetic metabolites into the inner membrane transport systems. Three VDAC isoforms exist in mammalian, but their specific role is unknown. In this work we have performed extensive (overall ∼5 µs Molecular Dynamics (MD simulations of the human VDAC isoforms to detect structural and conformational variations among them, possibly related to specific functional roles of these proteins. Secondary structure analysis of the N-terminal domain shows a high similarity among the three human isoforms of VDAC but with a different plasticity. In particular, the N-terminal domain of the hVDAC1 is characterized by a higher plasticity, with a ∼20% occurrence for the 'unstructured' conformation throughout the folded segment, while hVDAC2, containing a peculiar extension of 11 amino acids at the N-terminal end, presents an additional 310-helical folded portion comprising residues 10' to 3, adhering to the barrel wall. The N-terminal sequences of hVDAC isoforms are predicted to have a low flexibility, with possible consequences in the dynamics of the human VDACs. Clear differences were found between hVDAC1 and hVDAC3 against hVDAC2: a significantly modified dynamics with possible important consequence on the voltage-gating mechanism. Charge distribution inside and at the mouth of the pore is responsible for a different preferential localization of ions with opposite charge and provide a valuable rationale for hVDAC1 and hVDAC3 having a Cl-/K+ selectivity ratio of 1.8, whereas hVDAC2 of 1.4. Our conclusion is that hVDAC isoforms, despite sharing a similar scaffold, have modified working features and a biological work is now requested to give evidence to the described dissimilarities.

  7. Hsp70 Isoforms Are Essential for the Formation of Kaposi's Sarcoma-Associated Herpesvirus Replication and Transcription Compartments.

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    Belinda Baquero-Pérez

    2015-11-01

    Full Text Available Kaposi's sarcoma-associated herpesvirus (KSHV is an oncogenic herpesvirus associated with various AIDS-related malignancies. Like other herpesviruses, multiple processes required for KSHV lytic replication, including viral transcription, viral DNA synthesis and capsid assembly occur in virus-induced intranuclear structures, termed replication and transcription compartments (RTCs. Here we utilised a novel methodology, combining subcellular fractionation and quantitative proteomics, to identify cellular proteins which are recruited to KSHV-induced RTCs and thus play a key role in KSHV lytic replication. We show that several isoforms of the HSP70 chaperone family, Hsc70 and iHsp70, are redistributed from the cytoplasm into the nucleus coinciding with the initial formation of KSHV-induced RTCs. We demonstrate that nuclear chaperone foci are dynamic, initially forming adjacent to newly formed KSHV RTCs, however during later time points the chaperones move within KSHV RTCs and completely co-localise with actively replicating viral DNA. The functional significance of Hsp70 isoforms recruitment into KSHV RTCs was also examined using the specific Hsp70 isoform small molecule inhibitor, VER-155008. Intriguingly, results highlight an essential role of Hsp70 isoforms in the KSHV replication cycle independent of protein stability and maturation. Notably, inhibition of Hsp70 isoforms precluded KSHV RTC formation and RNA polymerase II (RNAPII relocalisation to the viral genome leading to the abolishment of global KSHV transcription and subsequent viral protein synthesis and DNA replication. These new findings have revealed novel mechanisms that regulate KSHV lytic replication and highlight the potential of HSP70 inhibitors as novel antiviral agents.

  8. Does Japanese medaka (Oryzias latipes) exhibit a gill Na(+)/K(+)-ATPase isoform switch during salinity change?

    Science.gov (United States)

    Bollinger, Rebecca J; Madsen, Steffen S; Bossus, Maryline C; Tipsmark, Christian K

    2016-05-01

    Some euryhaline teleosts exhibit a switch in gill Na(+)/K(+)-ATPase (Nka) α isoform when moving between fresh water (FW) and seawater (SW). The present study tested the hypothesis that a similar mechanism is present in Japanese medaka and whether salinity affects ouabain, Mg(2+), Na(+) and K(+) affinity of the gill enzyme. Phylogenetic analysis classified six separate medaka Nka α isoforms (α1a, α1b, α1c, α2, α3a and α3b). Medaka acclimated long-term (>30 days) to either FW or SW had similar gill expression of α1c, α2, α3a and α3b, while both α1a and α1b were elevated in SW. Since a potential isoform shift may rely on early changes in transcript abundance, we conducted two short-term (1-3 days) salinity transfer experiments. FW to SW acclimation induced an elevation of α1b and α1a after 1 and 3 days. SW to FW acclimation reduced α1b after 3 days with no other α isoforms affected. To verify that the responses were typical, additional transport proteins were examined. Gill ncc and nhe3 expression were elevated in FW, while cftr and nkcc1a were up-regulated in SW. This is in accordance with putative roles in ion-uptake and secretion. SW-acclimated medaka had higher gill Nka V max and lower apparent K m for Na(+) compared to FW fish, while apparent affinities for K(+), Mg(2+) and ouabain were unchanged. The present study showed that the Japanese medaka does not exhibit a salinity-induced α isoform switch and therefore suggests that Na(+) affinity changes involve altered posttranslational modification or intermolecular interactions. PMID:26920794

  9. Subcellular localization and responses of superoxide dismutase isoforms in local wheat varieties subjected to continuous soil drought.

    Science.gov (United States)

    Huseynova, Irada M; Aliyeva, Durna R; Aliyev, Jalal A

    2014-08-01

    Water is a key factor influencing the yield and quality of crops. One of the parameters of plant biological tolerance to constantly changing environmental conditions is the change of activities and numerous molecular forms of antioxidant enzymes. Two durum (Triticum durum Desf.) wheat varieties contrasting for drought tolerance, such as Barakatli-95 (drought tolerant) and Garagylchyg-2 (drought sensitive) were grown over a wide area in the field. Experiments were carried out to study the effect of soil drought on changes in activities and subcellular localization of superoxide dismutase isoforms. The levels of malondialdehyde, glycine betaine and total proteins were also analyzed. The level of the enzyme activity appeared to depend on the wheat varieties, duration of drought and stages of leaf development. Native polyacrylamide gel electrophoresis (PAGE) revealed the presence of 9 isoenzymes of superoxide dismutase in wheat leaves during drought. Mn-SOD was found in the mitochondrial fractions, Fe-SOD in the chloroplast fraction and Cu/Zn-SOD is localized in all subcellular fractions. Wheat leaves contain three different isoforms of SOD (Mn-, Fe-, Cu/Zn-SOD). Three isoforms of Mn-SOD, one isoform of Fe-SOD and five of Cu/Zn-SOD were observed in wheat leaves using 3 mM KCN and 5 mM H2O2 as selective inhibitors. The expression of Mn-SOD was preferentially enhanced by drought stress. It seems that Mn-SOD isoforms more than SOD ones play a major role in the scavenging of superoxide radicals. The observed data showed that status of antioxidant enzymes such as SOD could provide a meaningful tool for depicting drought tolerance of wheat genotype. PMID:24560039

  10. The Role of MAPT Haplotype H2 and Isoform 1N/4R in Parkinsonism of Older Adults.

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    Guilherme T Valenca

    Full Text Available Recently, we have shown that the Parkinson's disease (PD susceptibility locus MAPT (microtubule associated protein tau is associated with parkinsonism in older adults without a clinical diagnosis of PD. In this study, we investigated the relationship between parkinsonian signs and MAPT transcripts by assessing the effect of MAPT haplotypes on alternative splicing and expression levels of the most common isoforms in two prospective clinicopathologic studies of aging.using regression analysis, controlling for age, sex, study and neuropathology, we evaluated 976 subjects with clinical, genotyping and brain pathology data for haplotype analysis. For transcript analysis, we obtained MAPT gene and isoform-level expression from the dorsolateral prefrontal cortex for 505 of these subjects.The MAPT H2 haplotype was associated with lower total MAPT expression (p = 1.2x10-14 and global parkinsonism at both study entry (p = 0.001 and proximate to death (p = 0.050. Specifically, haplotype H2 was primarily associated with bradykinesia in both assessments (p<0.001 and p = 0.008. MAPT total expression was associated with age and decreases linearly with advancing age (p<0.001. Analysing MAPT alternative splicing, the expression of 1N/4R isoform was inversely associated with global parkinsonism (p = 0.008 and bradykinesia (p = 0.008. Diminished 1N/4R isoform expression was also associated with H2 (p = 0.001.Overall, our results suggest that age and H2 are associated with higher parkinsonism score and decreased total MAPT RNA expression. Additionally, we found that H2 and parkinsonism are associated with altered expression levels of specific isoforms. These findings may contribute to the understanding of the association between MAPT locus and parkinsonism in elderly subjects and in some extent to age-related neurodegenerative diseases.

  11. Requirement of PML SUMO interacting motif for RNF4- or arsenic trioxide-induced degradation of nuclear PML isoforms.

    Science.gov (United States)

    Maroui, Mohamed Ali; Kheddache-Atmane, Sabrina; El Asmi, Faten; Dianoux, Laurent; Aubry, Muriel; Chelbi-Alix, Mounira K

    2012-01-01

    PML, the organizer of nuclear bodies (NBs), is expressed in several isoforms designated PMLI to VII which differ in their C-terminal region due to alternative splicing of a single gene. This variability is important for the function of the different PML isoforms. PML NB formation requires the covalent linkage of SUMO to PML. Arsenic trioxide (As₂O₃) enhances PML SUMOylation leading to an increase in PML NB size and promotes its interaction with RNF4, a poly-SUMO-dependent ubiquitin E3 ligase responsible for proteasome-mediated PML degradation. Furthermore, the presence of a bona fide SUMO Interacting Motif (SIM) within the C-terminal region of PML seems to be required for recruitment of other SUMOylated proteins within PML NBs. This motif is present in all PML isoforms, except in the nuclear PMLVI and in the cytoplasmic PMLVII. Using a bioluminescence resonance energy transfer (BRET) assay in living cells, we found that As₂O₃ enhanced the SUMOylation and interaction with RNF4 of nuclear PML isoforms (I to VI). In addition, among the nuclear PML isoforms, only the one lacking the SIM sequence, PMLVI, was resistant to As₂O₃-induced PML degradation. Similarly, mutation of the SIM in PMLIII abrogated its sensitivity to As₂O₃-induced degradation. PMLVI and PMLIII-SIM mutant still interacted with RNF4. However, their resistance to the degradation process was due to their inability to be polyubiquitinated and to recruit efficiently the 20S core and the β regulatory subunit of the 11S complex of the proteasome in PML NBs. Such resistance of PMLVI to As₂O₃-induced degradation was alleviated by overexpression of RNF4. Our results demonstrate that the SIM of PML is dispensable for PML SUMOylation and interaction with RNF4 but is required for efficient PML ubiquitination, recruitment of proteasome components within NBs and proteasome-dependent degradation of PML in response to As₂O₃. PMID:23028697

  12. Requirement of PML SUMO interacting motif for RNF4- or arsenic trioxide-induced degradation of nuclear PML isoforms.

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    Mohamed Ali Maroui

    Full Text Available PML, the organizer of nuclear bodies (NBs, is expressed in several isoforms designated PMLI to VII which differ in their C-terminal region due to alternative splicing of a single gene. This variability is important for the function of the different PML isoforms. PML NB formation requires the covalent linkage of SUMO to PML. Arsenic trioxide (As₂O₃ enhances PML SUMOylation leading to an increase in PML NB size and promotes its interaction with RNF4, a poly-SUMO-dependent ubiquitin E3 ligase responsible for proteasome-mediated PML degradation. Furthermore, the presence of a bona fide SUMO Interacting Motif (SIM within the C-terminal region of PML seems to be required for recruitment of other SUMOylated proteins within PML NBs. This motif is present in all PML isoforms, except in the nuclear PMLVI and in the cytoplasmic PMLVII. Using a bioluminescence resonance energy transfer (BRET assay in living cells, we found that As₂O₃ enhanced the SUMOylation and interaction with RNF4 of nuclear PML isoforms (I to VI. In addition, among the nuclear PML isoforms, only the one lacking the SIM sequence, PMLVI, was resistant to As₂O₃-induced PML degradation. Similarly, mutation of the SIM in PMLIII abrogated its sensitivity to As₂O₃-induced degradation. PMLVI and PMLIII-SIM mutant still interacted with RNF4. However, their resistance to the degradation process was due to their inability to be polyubiquitinated and to recruit efficiently the 20S core and the β regulatory subunit of the 11S complex of the proteasome in PML NBs. Such resistance of PMLVI to As₂O₃-induced degradation was alleviated by overexpression of RNF4. Our results demonstrate that the SIM of PML is dispensable for PML SUMOylation and interaction with RNF4 but is required for efficient PML ubiquitination, recruitment of proteasome components within NBs and proteasome-dependent degradation of PML in response to As₂O₃.

  13. The absence of dystrophin brain isoform expression in healthy human heart ventricles explains the pathogenesis of 5' X-linked dilated cardiomyopathy

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    Neri Marcella

    2012-03-01

    Full Text Available Abstract Background In X-linked dilated cardiomyopathy due to dystrophin mutations which abolish the expression of the M isoform (5'-XLDC, the skeletal muscle is spared through the up-regulation of the Brain (B isoform, a compensatory mechanism that does not appear to occur in the heart of affected individuals. Methods We quantitatively studied the expression topography of both B and M isoforms in various human heart regions through in-situ RNA hybridization, Reverse-Transcriptase and Real-Time PCR experiments. We also investigated the methylation profile of the B promoter region in the heart and quantified the B isoform up regulation in the skeletal muscle of two 5'-XLDC patients. Results Unlike the M isoform, consistently detectable in all the heart regions, the B isoform was selectively expressed in atrial cardiomyocytes, but absent in ventricles and in conduction system structures. Although the level of B isoform messenger in the skeletal muscle of 5'-XLDC patients was lower that of the M messenger present in control muscle, it seems sufficient to avoid an overt muscle pathology. This result is consistent with the protein level in XLDC patients muscles we previously quantified. Methylation studies revealed that the B promoter shows an overall low level of methylation at the CG dinucleotides in both atria and ventricles, suggesting a methylation-independent regulation of the B promoter activity. Conclusions The ventricular dilatation seen in 5'-XLDC patients appears to be functionally related to loss of the M isoform, the only isoform transcribed in human ventricles; in contrast, the B isoform is well expressed in heart but confined to the atria. Since the B isoform can functionally replace the M isoform in the skeletal muscle, its expression in the heart could potentially exert the same rescue function. Methylation status does not seem to play a role in the differential B promoter activity in atria and ventricles, which may be governed by

  14. Evolution of a TRIM5-CypA splice isoform in old world monkeys.

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    Ruchi M Newman

    2008-02-01

    Full Text Available The TRIM family proteins share a conserved arrangement of three adjacent domains, an N-terminal RING domain, followed by one or two B-boxes and a coiled-coil, which constitutes the tripartite-motif for which the family is named. However, the C-termini of TRIM proteins vary, and include at least nine evolutionarily distinct, unrelated protein domains. Antiviral restriction factor TRIM5alpha has a C-terminal B30.2/SPRY domain, which is the major determinant of viral target specificity. Here, we describe the evolution of a cyclophilin-A encoding exon downstream of the TRIM5 locus of Asian macaques. Alternative splicing gives rise to chimeric transcripts encoding the TRIM motif fused to a C-terminal CypA domain (TRIM5-CypA. We detected TRIM5-CypA chimeric transcripts in primary lymphocytes from two macaque species. These were derived in part from a CypA pseudogene in the TRIM5 locus, which is distinct from the previously described CypA insertion in TRIM5 of owl monkeys. The CypA insertion is linked to a mutation in the 3' splice site upstream of exon 7, which may prevent or reduce expression of the alpha-isoform. All pig-tailed macaques (M. nemestrina screened were homozygous for the CypA insertion. In contrast, the CypA-containing allele was present in 17% (17/101 of rhesus macaques (M. mulatta. The block to HIV-1 infection in lymphocytes from animals bearing the TRIM5-CypA allele was weaker than that in cells from wild type animals. HIV-1 infectivity remained significantly lower than SIV infectivity, but was not rescued by treatment with cyclosporine A. Thus, unlike owl monkey TRIMCyp, expression of the macaque TRIM5-CypA isoform does not result in increased restriction of HIV-1. Despite its distinct evolutionary origin, Macaca TRIM5-CypA has a similar domain arrangement and shares approximately 80% amino-acid identity with the TRIMCyp protein of owl monkeys. The independent appearance of TRIM5-CypA chimeras in two primate lineages constitutes a

  15. Non-redundant functions of two proline dehydrogenase isoforms in Arabidopsis

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    Müller Gudrun

    2010-04-01

    Full Text Available Abstract Background Proline (Pro accumulation is a widespread response of prokaryotic and eukaryotic cells subjected to osmotic stress or dehydration. When the cells are released from stress, Pro is degraded to glutamate by Pro-dehydrogenase (ProDH and Pyrroline-5-carboxylate dehydrogenase (P5CDH, which are both mitochondrial enzymes in eukaryotes. While P5CDH is a single copy gene in Arabidopsis, two ProDH genes have been identified in the genome. Until now, only ProDH1 (At3g30775 had been functionally characterised. Results We demonstrate vasculature specific expression of the Arabidopsis ProDH2 gene (At5g38710 as well as enzymatic activity and mitochondrial localisation of the encoded protein. Expression levels of ProDH2 are generally low, but increased in senescent leaves and in the abscission zone of floral organs. While sucrose represses ProDH2 expression, Pro and NaCl were identified as inducers. Endogenous ProDH2 expression was not able to overcome Pro sensitivity of ProDH1 mutants, but overexpression of a GFP-tagged form of ProDH2 enabled the utilisation of Pro as single nitrogen source for growth. Amongst two intronic insertion mutants, one was identified as a null allele, whereas the other still produced native ProDH2 transcripts. Conclusions Arabidopsis possesses two functional ProDHs, which have non-redundant, although partially overlapping physiological functions. The two ProDH isoforms differ with respect to spatial, developmental and environmental regulation of expression. While ProDH1 appears to be the dominant isoform under most conditions and in most tissues, ProDH2 was specifically upregulated during salt stress, when ProDH1 was repressed. The characterisation of ProDH2 as a functional gene requires a careful re-analysis of mutants with a deletion of ProDH1, which were so far considered to be devoid of ProDH activity. We hypothesise that ProDH2 plays an important role in Pro homeostasis in the vasculature, especially under

  16. Proteomic analysis of glutathione S-transferase isoforms in mouse liver mitochondria

    Institute of Scientific and Technical Information of China (English)

    Hai-Dan Sun; Ya-Wei Ru; Dong-Juan Zhang; Song-Yue Yin; Liang Yin; Ying-Ying Xie; You-Fei Guan; Si-Qi Liu

    2012-01-01

    AIM:To survey glutathione (GSH) S-transferase (GST)isoforms in mitochondria and to reveal the isoforms' biological significance in diabetic mice.METHODS:The presence of GSTs in mouse liver mitochondria was systematically screened by two proteomic approaches,namely,GSH affinity chromatography/two dimensional electrophoresis (2DE/MALDI TOF/TOFMS) and SDS-PAGE/LC ESI MS/MS.The proteomic results were further confirmed by Western blotting using monoclonal antibodies against GSTs.To evaluate the liver mitochondrial GSTs quantitatively,calibration curves were generated by the loading amounts of individual recombinant GST protein vs the relative intensities elicited from the Western blotting.An extensive comparison of the liver mitochondrial GSTs was conducted between normal and db/db diabetic mice.Student's t test was adopted for the estimation of regression and significant difference.RESULTS:Using GSH affinity/2DF/MALDI TOF/TOF MS,three GSTs,namely,alpha3,mu1 and pi1,were identified; whereas five GSTs,alpha3,mu1,pi1,kappa1 and zeta1,were detected in mouse liver mitochondria using SDS-PAGE/LC ESI MS/MS,of these GSTs,GST kappa1 was reported as a specific mitochondrial GST.The R2 values of regression ranged between values of about 0.86 and 0.98,which were acceptable for the quantification.Based on the measurement of the GST abundances in liver mitochondria of normal and diabetic mice,the four GSTs,alpha3,kappa1,mu1 and zeta1,were found to be almost comparable between the two sets of animals,whereas,lower GST pi1 was detected in the diabetic mice compared with normal ones,the signal of Western blotting in control and db/ db diabetic mice liver mitochondria is 134.61 ± 53.84vs 99.74 ± 46.2,with P < 0.05.CONCLUSION:Our results indicate that GSTs exist widely in mitochondria and its abundances of mitochondrial GSTs might be tissue-dependent and disease-related.

  17. p53 isoform Δ113p53 is a p53 target gene that antagonizes p53 apoptotic activity via BclxL activation in zebrafish

    OpenAIRE

    Chen, Jun; Ng, Sok Meng; Chang, Changqing; Zhang, Zhenhai; Bourdon, Jean-Christophe; Lane, David P; Peng, Jinrong

    2009-01-01

    p53 is a well-known tumor suppressor and is also involved in processes of organismal aging and developmental control. A recent exciting development in the p53 field is the discovery of various p53 isoforms. One p53 isoform is human Δ133p53 and its zebrafish counterpart Δ113p53. These N-terminal-truncated p53 isoforms are initiated from an alternative p53 promoter, but their expression regulation and physiological significance at the organismal level are not well understood. We show here that ...

  18. Protein chemical characterization of Gc globulin (vitamin D-binding protein) isoforms; Gc-1f, Gc-1s and Gc-2

    DEFF Research Database (Denmark)

    Christiansen, Maja; Jørgensen, Charlotte S; Laursen, Inga; Hirschberg, Daniel; Højrup, Peter; Houen, Gunnar

    2007-01-01

    (Gc-1s) and a Thr/Lys substitution (Gc-2) in agreement with DNA sequencing studies. The commercial preparations were found to represent mainly one or two isoforms. An O-linked glycan with a mass of 656 Da and terminating with a sialic acid residue was detected on a minor proportion of Gc globulin...... patients with fulminant hepatic failure and trauma. Here, we characterize the dominant isoforms of plasma-derived Gc globulin from Cohn fraction IV paste with respect to amino acid sequence and posttranslational modifications. Gc globulin was purified in large scale and the isoforms separated by ion...

  19. In vivo analysis of Saccharomyces cerevisiae plasma membrane ATPase Pma1p isoforms with increased in vitro H+/ATP stoichiometry

    OpenAIRE

    Kok, S.; Yilmaz, D.; Daran, J.M.; Pronk, J T; van Maris, A. J. A.

    2012-01-01

    Plasma membrane H+-ATPase isoforms with increased H+/ATP ratios represent a desirable asset in yeast metabolic engineering. In vivo proton coupling of two previously reported Pma1p isoforms (Ser800Ala, Glu803Gln) with increased in vitro H+/ATP stoichiometries was analysed by measuring biomass yields of anaerobic maltose-limited chemostat cultures expressing only the different PMA1 alleles. In vivo H+/ATP stoichiometries of wildtype Pma1p and the two isoforms did not differ significantly.

  20. Differential expression of hERG1 channel isoforms reproduces properties of native I(Kr) and modulates cardiac action potential characteristics

    DEFF Research Database (Denmark)

    Larsen, Anders Peter; Olesen, Søren-Peter

    2010-01-01

    The repolarizing cardiac rapid delayed rectifier current, I(Kr), is composed of ERG1 channels. It has been suggested that two isoforms of the ERG1 protein, ERG1a and ERG1b, both contribute to I(Kr). Marked heterogeneity in the kinetic properties of native I(Kr) has been described. We hypothesized...... that the heterogeneity of native I(Kr) can be reproduced by differential expression of ERG1a and ERG1b isoforms. Furthermore, the functional consequences of differential expression of ERG1 isoforms were explored as a potential mechanism underlying native heterogeneity of action potential duration (APD...

  1. Identification of two Sox17 messenger RNA isoforms, with and without the high mobility group box region, and their differential expression in mouse spermatogenesis

    OpenAIRE

    1996-01-01

    The different mRNA isoforms of the mouse Sox17 gene were isolated from adult mouse testis cDNAs. One form (referred to as form Sox17) encodes an Sry-related protein of 419 amino acids containing a single high mobility group box near the NH2-terminus, while the other form (referred to as form t-Sox17) shows a unique mRNA isoform of the Sox17 gene with a partial deletion of the HMG box region. Analysis of genomic DNA revealed that these two isoforms were produced at least by alternative splicin...

  2. Dynamic and Static Simulations of Fluvoxamine-Perpetrated Drug-Drug Interactions Using Multiple Cytochrome P450 Inhibition Modeling, and Determination of Perpetrator-Specific CYP Isoform Inhibition Constants and Fractional CYP Isoform Contributions to Victim Clearance.

    Science.gov (United States)

    Iga, Katsumi

    2016-03-01

    Fluvoxamine-perpetrated drug-drug interactions (DDIs) of victims metabolized by multiple cytochrome P450 isoforms (CYP1A2, CYP2C19, and CYP3A4) were simulated using 2 compartment-based tube modeling, assuming a multiple inhibition-constant (Ki) model, as well as a previously reported single Ki model. Good fittings were obtained for all DDIs using consistent perpetrator-specific CYP isoform Kis and fractional CYP isoform contributions to victim clearance in concordance with literature information. Through these simulations, the following rules to predict DDI were derived. Overall enzymatic inhibitory activity calculated from static DDI data determines entirely dynamic DDIs. DDI-relevant time-dependent hepatic blood unbound perpetrator levels can be approximated to mean hepatic blood unbound perpetrator levels in any victim DDIs when a perpetrator is supplied consistently. Static and dynamic multiple CYP model-based simulations agree with one another. Fluvoxamine-perpetrated DDIs can be bridged to other perpetrator DDIs. The derived rules will allow simpler prediction of DDIs from in vivo DDI databases. Tens or hundreds of Ki gaps between in vitro and in vivo data could be reduced to within severalfold using the liver-microsome contamination model, thus suggesting that microsomes qualified with contamination would greatly improve prediction of DDIs from in vitro data. PMID:26886336

  3. The p53 Isoform Δ133p53β Promotes Cancer Stem Cell Potential

    Directory of Open Access Journals (Sweden)

    Nikola Arsic

    2015-04-01

    Full Text Available Cancer stem cells (CSC are responsible for cancer chemoresistance and metastasis formation. Here we report that Δ133p53β, a TP53 splice variant, enhanced cancer cell stemness in MCF-7 breast cancer cells, while its depletion reduced it. Δ133p53β stimulated the expression of the key pluripotency factors SOX2, OCT3/4, and NANOG. Similarly, in highly metastatic breast cancer cells, aggressiveness was coupled with enhanced CSC potential and Δ133p53β expression. Like in MCF-7 cells, SOX2, OCT3/4, and NANOG expression were positively regulated by Δ133p53β in these cells. Finally, treatment of MCF-7 cells with etoposide, a cytotoxic anti-cancer drug, increased CSC formation and SOX2, OCT3/4, and NANOG expression via Δ133p53, thus potentially increasing the risk of cancer recurrence. Our findings show that Δ133p53β supports CSC potential. Moreover, they indicate that the TP53 gene, which is considered a major tumor suppressor gene, also acts as an oncogene via the Δ133p53β isoform.

  4. Amphibian ryanodine receptor isoforms are related to those of mammalian skeletal or cardiac muscle.

    Science.gov (United States)

    Lai, F A; Liu, Q Y; Xu, L; el-Hashem, A; Kramarcy, N R; Sealock, R; Meissner, G

    1992-08-01

    The ryanodine receptor (RyR)-Ca2+ release channels of frog skeletal muscle have been purified as 30S protein complexes comprised of two high molecular weight polypeptides. The upper and lower bands of the frog doublet comigrated on sodium dodecyl sulfate polyacylamide gels with the mammalian skeletal and cardiac RyR polypeptides, respectively. Immunoblot analysis showed that a polyclonal antiserum to the rat skeletal RyR preferentially cross-reacted with the upper band, whereas monoclonal antibodies to the canine cardiac RyR preferentially cross-reacted with the lower band of the frog receptor doublet. Immunoprecipitation studies indicated the presence of two homooligomer 30S RyR complexes comprised of either the lower or upper polypeptide band of the frog doublet, and immunocytochemical staining revealed their colocalization in frog gastrocnemius muscle. After planar lipid bilayer reconstitution of the 30S frog RyR, single-channel currents were observed that exhibited a Na+ and Ca2+ conductance and pharmacological characteristics similar to those of the mammalian skeletal and cardiac Ca2+ release channels. These results suggest that amphibian skeletal muscle expresses two distinct RyR isoforms that share epitopes in common with the mammalian skeletal or cardiac RyR. PMID:1325114

  5. Adiponectin Isoforms and Leptin Impact on Rheumatoid Adipose Mesenchymal Stem Cells Function

    Science.gov (United States)

    Skalska, Urszula; Kontny, Ewa

    2016-01-01

    Adiponectin and leptin have recently emerged as potential risk factors in rheumatoid arthritis (RA) pathogenesis. In this study we evaluated the effects of adiponectin and leptin on immunomodulatory function of adipose mesenchymal stem cells (ASCs) derived from infrapatellar fat pad of RA patients. ASCs were stimulated with leptin, low molecular weight (LMW) and high/middle molecular weight (HMW/MMW) adiponectin isoforms. The secretory activity of ASCs and their effect on rheumatoid synovial fibroblasts (RA-FLS) and peripheral blood mononuclear cells (PBMCs) from healthy donors have been analysed. RA-ASCs secreted spontaneously TGFβ, IL-6, IL-1Ra, PGE2, IL-8, and VEGF. Secretion of all these factors was considerably upregulated by HMW/MMW adiponectin, but not by LMW adiponectin and leptin. Stimulation with HMW/MMW adiponectin partially abolished proproliferative effect of ASC-derived soluble factors on RA-FLS but did not affect IL-6 secretion in FLS cultures. ASCs pretreated with HMW/MMW adiponectin maintained their anti-inflammatory function towards PBMCs, which was manifested by moderate PBMCs proliferation inhibition and IL-10 secretion induction. We have proved that HMW/MMW adiponectin stimulates secretory potential of rheumatoid ASCs but does not exert strong impact on ASCs function towards RA-FLS and PBMCs. PMID:26681953

  6. A short caspase-3 isoform inhibits chemotherapy-induced apoptosis by blocking apoptosome assembly.

    Directory of Open Access Journals (Sweden)

    Frédérique Végran

    Full Text Available Alternative splicing of caspase-3 produces a short isoform caspase-3s that antagonizes caspase-3 apoptotic activity. However, the mechanism of apoptosis inhibition by caspase-3s remains unknown. Here we show that exogenous caspase-3 sensitizes MCF-7 and HBL100 breast cancers cells to chemotherapeutic treatments such as etoposide and methotrexate whereas co-transfection with caspase-3s strongly inhibits etoposide and methotrexate-induced apoptosis underlying thus the anti-apoptotic role of caspase-3s. In caspase-3 transfected cells, lamin-A and α-fodrin were cleaved when caspase-3 was activated by etoposide or methotrexate. When caspase-3s was co-transfected, this cleavage was strongly reduced. Depletion of caspase-3 by RNA interference in HBL100 containing endogenous caspase-3s caused reduction in etoposide and methotrexate-induced apoptosis, whereas the depletion of caspase-3s sensitized cells to chemotherapy. In the presence of caspase-3s, a lack of interaction between caspase-3 and caspase-9 was observed. Immunoprecipitation assays showed that caspase-3s binds the pro-forms of caspase-3. This result suggested that the absence of interaction with caspase-9 when both variants of caspase-3 are present contribute to block the apoptosome assembly and inhibit apoptosis. These data support that caspases-3s negatively interferes with caspase-3 activation and apoptosis in breast cancer, and that it can play key roles in the modulation of response to chemotherapeutic treatments.

  7. Generation and characterization of mice transgenic for human IL-18-binding protein isoform a.

    Science.gov (United States)

    Fantuzzi, Giamila; Banda, Nirmal K; Guthridge, Carla; Vondracek, Andrea; Kim, Soo-Hyun; Siegmund, Britta; Azam, Tania; Sennello, Joseph A; Dinarello, Charles A; Arend, William P

    2003-11-01

    Interleukin (IL)-18 binding protein (IL-18BP) is a natural inhibitor of the pleiotropic cytokine IL-18. To study the role of IL-18BP in modulating inflammatory responses in vivo, mice transgenic for human IL-18BP isoform a (IL-18BP-Tg) were generated. The transgene was expressed at high levels in each organ examined. High levels of bioactive human IL-18BPa were detectable in the circulation of IL-18BP-Tg mice, which were viable, fertile, and had no tissue or organ abnormality. The high levels of IL-18BP in the transgenic mice were able to completely neutralize the interferon-gamma (IFN-gamma)-inducing activity of exogenously administered IL-18. Following administration of endotoxin, with or without prior sensitization with heat-inactivated Propionibacterium acnes, IL-18BP-Tg mice produced significantly lower serum levels of IFN-gamma and macrophage-inflammatory protein-2 compared with nontransgenic littermates. Significantly reduced production of IFN-gamma in response to endotoxin was also observed in cultures of IL-18BP-Tg splenocytes. Finally, IL-18BP-Tg mice were completely protected in a model of hepatotoxicity induced by administration of concanavalin A. These results indicate that high endogenous levels of IL-18BP in trangenic mice effectively neutralize IL-18 and are protective in response to different inflammatory stimuli. PMID:12960225

  8. Photo-control of nitric oxide synthase activity using a caged isoform specific inhibitor.

    Science.gov (United States)

    Montgomery, Heather J; Perdicakis, Basil; Fishlock, Dan; Lajoie, Gilles A; Jervis, Eric; Guy Guillemette, J

    2002-06-01

    Nitric oxide (NO) plays a critical role in a number of physiological processes and is produced in mammalian cells by nitric oxide synthase (NOS) isozymes. Because of the diverse functions of NO, pharmaceutical interventions which seek to abrogate adverse effects of excess NOS activity must not interfere with the normal regulation of NO levels in the body. A method has been developed for the control of NOS enzyme activity using the localized photochemical release of a caged isoform-specific NOS inhibitor. The caged form of an iNOS inhibitor has been synthesized and tested for photosensitivity and potency. UV and multiphoton uncaging were verified using a hemoglobin-based assay. IC(50) values were determined for the inhibitor (70+/-11 nM), the caged inhibitor (1098+/-172 nM), the UV uncaged inhibitor (67+/-26 nM) and the multiphoton uncaged inhibitor (73+/-11 nM). UV irradiation of the caged inhibitor resulted in a 86% reduction in iNOS activity after 5 min. Multiphoton uncaging had an apparent first order time constant of 0.007+/-0.001 min(-1). A therapeutic range exists, with molar excess of inhibitor to enzyme from 3- to 7-fold, over which the full dynamic range of the inhibition can be exploited. PMID:11937350

  9. Alteration of cadherin isoform expression and inhibition of gap junctions in stomach carcinoma cells

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    To explore cell malignant phenotype correlated changes of cell surface adhesion molecules and cell-cell communication in carcinogenesis, human stomach transformed and cancer cell lines were investigated. Expressions of E-cadherin, N-cadherin, ?-catenin, ?-catenin as well as gap junction (GJ) protein Cx32 were studied by utilization of immunoblotting, immunocytochemical and fluorescent dye transfer methods. Mammalian normal stomach mucosal cells expressed E-cadherin but not N-cadherin. E-cadherin immunofluorescence was detected at cell membranous adherens junctions (AJ) where colocalization with immunofluorescent staining of inner surface adhesion plaque proteins ?- and ?-catenins was observed. The existence of E-cadherin/ catenin (?-, ?-) protein complexes as AJ was suggested. In transformed and stomach cancer cells E-cadherin was inhibited, instead, N-cadherin was expressed and localized at membranous AJ where co-staining with ?- and ?-catenin fluorescence was observed. Formation of N-cadherin/catenin (?-, ?-) protein complex at AJs of transformed and cancer cells was suggested. The above observations were further supported by immunoblotting results. Normal stomach muscosal and transformed cells expressed Cx32 at membranous GJ and were competent of gap junction communication (GJIC). In stomach cancer cells, Cx32 was inhibited and GJIC was defective. The results suggested that changes of signal pathways mediated by both cell adhesion and cell communication systems are associated intracellular events of stomach carcinogenesis. The alteration of cadherin isoform from E- to N-cadherin in transformed and stomach cancer cells is the first report.

  10. Mutagenesis of Genes for Starch Debranching Enzyme Isoforms in Pea by Zinc-Finger Endonucleases

    International Nuclear Information System (INIS)

    Starch debranching enzymes in plants are divided into two groups based on their ability to hydrolyze different substrates. The first group, pullulanases, hydrolyze α-1,6-glucosidic linkages in substrates such as pullulan, amylopectin and glycogen. The second group of debranching enzymes, isoamylases, hydrolyze glycogen and amylopectin and are not active on pullulan. Three isoforms of isoamylase and a pullulanase have been isolated from a cDNA library of Pisum sativum. These isoamylases have been characterized following their heterologous expression in E. coli. Based on the DNA sequence that encodes these debranching enzymes, a specific mutagenesis targeting these enzymes will be attempted. The technique involves the homologous recombination of DNA mediated by zinc-finger endonucleases. Vectors will be constructed to include a fragment that will modify these genes. Using this technique, it is hoped that null mutants for each enzyme will be created and the exact role of these enzymes for the synthesis and degradation of starch in plants will be elucidated. (author)

  11. Metallothionein 1 Isoform Gene Expression Induced by Cadmium in Human Peripheral Blood Lymphocytes

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    To study the gene expression of metallothionein 1 (MT-1) isoforms in human peripheral blood lymphocytes (HPBLs). Methods The expression of mRNA representing the seven active MT-1 genes was determined in HPBLs by quantitative RT-PCR before and after exposure to cadmium. Results Basal expressions of MT-1X, and MT-1A in HPBLs were similar to expression of housekeeping gene. In contrast, the basal gene expressions of MT-1H, 1F, 1E, and 1G were a little transcripts in human HPBLs. No signal was detected for MT-1B. There was a sex difference (P<0.05). in basal gene expression of MT-1E. The levels of gene expression of MT-1A, 1E, 1F, 1G, 1H, and 1X increased, but the level of MT-1B did not increase after exposure to cadmium. Conclusions Gene expressions of MT-1G, MT-1H, MT-1F, and MT-1X in HPBLs can be used as a potential biomarker of cadmium exposure.

  12. Contractile function is unaltered in diaphragm from mice lacking calcium release channel isoform 3

    Science.gov (United States)

    Clancy, J. S.; Takeshima, H.; Hamilton, S. L.; Reid, M. B.

    1999-01-01

    Skeletal muscle expresses at least two isoforms of the calcium release channel in the sarcoplasmic reticulum (RyR1 and RyR3). Whereas the function of RyR1 is well defined, the physiological significance of RyR3 is unclear. Some authors have suggested that RyR3 participates in excitation-contraction coupling and that RyR3 may specifically confer resistance to fatigue. To test this hypothesis, we measured contractile function of diaphragm strips from adult RyR3-deficient mice (exon 2-targeted mutation) and their heterozygous and wild-type littermates. In unfatigued diaphragm, there were no differences in isometric contractile properties (twitch characteristics, force-frequency relationships, maximal force) among the three groups. Our fatigue protocol (30 Hz, 0.25 duty cycle, 37 degrees C) depressed force to 25% of the initial force; however, lack of RyR3 did not accelerate the decline in force production. The force-frequency relationship was shifted to higher frequencies and was depressed in fatigued diaphragm; lack of RyR3 did not exaggerate these changes. We therefore provide evidence that RyR3 deficiency does not alter contractile function of adult muscle before, during, or after fatigue.

  13. Glycoprotein D actively induces rapid internalization of two nectin-1 isoforms during herpes simplex virus entry

    International Nuclear Information System (INIS)

    Entry of herpes simplex virus (HSV) occurs either by fusion at the plasma membrane or by endocytosis and fusion with an endosome. Binding of glycoprotein D (gD) to a receptor such as nectin-1 is essential in both cases. We show that virion gD triggered the rapid down-regulation of nectin-1 with kinetics similar to those of virus entry. In contrast, nectin-1 was not constitutively recycled from the surface of uninfected cells. Both the nectin-1α and β isoforms were internalized in response to gD despite having different cytoplasmic tails. However, deletion of the nectin-1 cytoplasmic tail slowed down-regulation of nectin-1 and internalization of virions. These data suggest that nectin-1 interaction with a cytoplasmic protein is not required for its down-regulation. Overall, this study shows that gD binding actively induces the rapid internalization of various forms of nectin-1. We suggest that HSV activates a nectin-1 internalization pathway to use for endocytic entry.

  14. A Single Aplysia Neurotrophin Mediates Synaptic Facilitation via Differentially Processed Isoforms

    Directory of Open Access Journals (Sweden)

    Stefan R. Kassabov

    2013-04-01

    Full Text Available Neurotrophins control the development and adult plasticity of the vertebrate nervous system. Failure to identify invertebrate neurotrophin orthologs, however, has precluded studies in invertebrate models, limiting our understanding of fundamental aspects of neurotrophin biology and function. We identified a neurotrophin (ApNT and Trk receptor (ApTrk in the mollusk Aplysia and found that they play a central role in learning-related synaptic plasticity. Blocking ApTrk signaling impairs long-term facilitation, whereas augmenting ApNT expression enhances it and induces the growth of new synaptic varicosities at the monosynaptic connection between sensory and motor neurons of the gill-withdrawal reflex. Unlike vertebrate neurotrophins, ApNT has multiple coding exons and exerts distinct synaptic effects through differentially processed and secreted splice isoforms. Our findings demonstrate the existence of bona fide neurotrophin signaling in invertebrates and reveal a posttranscriptional mechanism that regulates neurotrophin processing and the release of proneurotrophins and mature neurotrophins that differentially modulate synaptic plasticity.

  15. Epimorphin is a novel regulator of the progesterone receptor isoform-a.

    Science.gov (United States)

    Bascom, Jamie L; Radisky, Derek C; Koh, Eileen; Fata, Jimmie E; Lo, Alvin; Mori, Hidetoshi; Roosta, Neda; Hirai, Yohei; Bissell, Mina J

    2013-09-15

    Epimorphin/syntaxin-2 is a membrane-tethered protein localized extracellularly (Epim) and intracellularly (Stx-2). The extracellular form Epim stimulates morphogenic processes in a range of tissues, including in murine mammary glands where its overexpression in luminal epithelial cells is sufficient to drive hyperplasia and neoplasia. We analyzed WAP-Epim transgenic mice to gain insight into how Epim promotes malignancy. Ectopic overexpression of Epim during postnatal mammary gland development led to early side-branching onset, precocious bud formation, and increased proliferation of mammary epithelial cells. Conversely, peptide-based inhibition of Epim function reduced side branching. Because increased side branching and hyperplasia occurs similarly in mice upon overexpression of the progesterone receptor isoform-a (Pgr-a), we investigated whether Epim exhibits these phenotypes through Pgr modulation. Epim overexpression indeed led to a steep upregulation of both total Pgr mRNA and Pgr-a protein levels. Notably, the Pgr antagonist RU486 abrogated Epim-induced ductal side branching, mammary epithelial cell proliferation, and bud formation. Evaluation of Epim signaling in a three-dimensional ex vivo culture system showed that its action was dependent on binding to its extracellular receptor, integrin-αV, and on matrix metalloproteinase 3 activity downstream of Pgr-a. These findings elucidate a hitherto unknown transcriptional regulator of Pgr-a, and shed light on how overexpression of Epim leads to malignancy. PMID:23867473

  16. Assignment and expression patterns of porcine muscle-specific isoform of phosphoglycerate mutase gene

    Institute of Scientific and Technical Information of China (English)

    Haifang Qiu; Shuhong Zhao; Xuewen Xu; Martine Yerle; Bang Liu

    2008-01-01

    It has been reported that the muscle-specific isoform (type M, PGAM2) of phosphoglycerate mutase (PGAM) is a housekeeping en-zyme; it catalyzes the conversion of 3-phospboglycerate into 2-phosphoglycerate in the glyeolysis process to release energy. It is encoded by the Pgam2 gene. In this study, the eDNA of the porcine Pgam2 was cloned. This gene contains an open reading frame of 765 bp en-coding a protein of 253 residues, and the predicted protein sequences share high similarity with other mammalians, 96% identity with humans, and 94% identity with mouse and rats. Pgam2 was mapped to SSC18q13-q21 by the RH panel. In this region, there are several QTLs, such as fat ratio, lean percentage, and diameter of muslce fiber, which affect meat production and quality. The reverse transcrip-tase-polymerase chain reaction revealed that the porcine Pgam2 gene was mainly expressed in the muscle tissue (skeletal muscle and cardiac muscle), and was expressed highly at skeletal muscle development stages (embryonic periods: 33, 65, and 90 days post-conception(dpe); postnatal pigs: 4 days and adult). This indicates that the Pgam2 gene plays an important role in muscle growth and development. In addition, it was demonstrated that PGAM2 locates both in cytoplasm and nuclei, and takes part in the glycometabolism process of cyto-plasm and nuclei.

  17. The Effects of Acute Hydrogen Sulfide Poisoning on Cytochrome P450 Isoforms Activity in Rats

    Directory of Open Access Journals (Sweden)

    Xianqin Wang

    2014-01-01

    Full Text Available Hydrogen sulfide (H2S is the second leading cause of toxin related death (after carbon monoxide in the workplace. H2S is absorbed by the upper respiratory tract mucosa, and it causes histotoxic hypoxemia and respiratory depression. Cocktail method was used to evaluate the influences of acute H2S poisoning on the activities of cytochrome P450 isoforms CYP2B6, CYP2D6, CYP3A4, CYP1A2, CYP2C19, and CYP2C9, which were reflected by the changes of pharmacokinetic parameters of six specific probe drugs, bupropion, metoprolol, midazolam, phenacetin, omeprazole, and tolbutamide, respectively. The experimental rats were randomly divided into two groups, control group and acute H2S poisoning group (inhaling 300 ppm for 2 h. The mixture of six probes was given to rats by oral administration and the blood samples were obtained at a series of time points through the caudal vein. The concentrations of probe drugs in rat plasma were measured by LC-MS. The results for acute H2S poisoning and control groups were as follows: there was a statistically significant difference in the AUC and Cmax for bupropion, metoprolol, phenacetin, and tolbutamide, while there was no statistical pharmacokinetic difference for midazolam and omeprazole. Acute H2S poisoning could inhibit the activity of CYP2B6, CYP2D6, CYP1A2, and CYP2C9 in rats.

  18. Purification and characterization of an isoform of protein kinase C from bovine neutrophils

    International Nuclear Information System (INIS)

    Protein kinase C (PKC) from bovine neutrophils was purified 1,420-fold. Subcellular fractionation analysis of bovine neutrophil homogenate in the presence of EGTA indicated that more than 95% of the PKC activity was present in the soluble fraction. Whereas bovine brain PKC could be resolved into four isoenzymatic forms by chromatography on a hydroxylapatite column, bovine neutrophil PKC was eluted in a single peak, suggesting that it corresponded to a single isoform. The apparent molecular weight of bovine neutrophil PKC was 82,000, as judged by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Bovine neutrophil PKC was autophosphorylated in the presence of [γ-32P]ATP, provided that the medium was supplemented with Mg2+, Ca2+, phosphatidylserine, and diacylglycerol; phorbol myristate acetate could substitute for diacylglycerol. Autophosphorylated PKC could be cleaved by trypsin to generate two radiolabeled peptides of Mr 48,000 and 39,000. The labeled amino acids were serine and threonine. During the course of the purification procedure of bovine neutrophil PKC, a protein of Mr 23,000 was found to exhibit a strong propensity to PKC-dependent phosphorylation in the presence of [γ-32P]ATP, Mg2+, Ca2+, phosphatidylserine, and diacylglycerol. This protein was recovered together with PKC in one of the two active peaks eluted from the Mono Q column at the second step of PKC purification. It is suggested that the Mr 23,000 protein might be a natural substrate for bovine neutrophil PKC

  19. Characterization of Affinity-Purified Isoforms of Acinetobacter calcoaceticus Y1 Glutathione Transferases

    Directory of Open Access Journals (Sweden)

    Chin-Soon Chee

    2014-01-01

    Full Text Available Glutathione transferases (GST were purified from locally isolated bacteria, Acinetobacter calcoaceticus Y1, by glutathione-affinity chromatography and anion exchange, and their substrate specificities were investigated. SDS-polyacrylamide gel electrophoresis revealed that the purified GST resolved into a single band with a molecular weight (MW of 23 kDa. 2-dimensional (2-D gel electrophoresis showed the presence of two isoforms, GST1 (pI 4.5 and GST2 (pI 6.2 with identical MW. GST1 was reactive towards ethacrynic acid, hydrogen peroxide, 1-chloro-2,4-dinitrobenzene, and trans,trans-hepta-2,4-dienal while GST2 was active towards all substrates except hydrogen peroxide. This demonstrated that GST1 possessed peroxidase activity which was absent in GST2. This study also showed that only GST2 was able to conjugate GSH to isoproturon, a herbicide. GST1 and GST2 were suggested to be similar to F0KLY9 (putative glutathione S-transferase and F0KKB0 (glutathione S-transferase III of Acinetobacter calcoaceticus strain PHEA-2, respectively.

  20. Comparison of fecal pyruvate kinase isoform M2 and calprotectin in acute diarrhea in hospitalized children

    Science.gov (United States)

    Czub, Elzbieta; Nowak, Jan K.; Moczko, Jerzy; Lisowska, Aleksandra; Banaszkiewicz, Aleksandra; Banasiewicz, Tomasz; Walkowiak, Jaroslaw

    2014-01-01

    Fecal concentrations of pyruvate kinase isoform M2 (M2-PK) and calprotectin (FC) serve as biomarkers of inflammation of gastrointestinal mucosa. The value of M2-PK in discriminating between patients with viral and bacterial acute diarrhea (AD) is currently unknown. We analyzed M2-PK and FC concentrations in fifty hospitalized children with AD (29 of which were caused by rotavirus and 21 by Salmonella enteritidis) as well as 32 healthy subjects. There was no difference in the areas under the receiver operating characteristic curves plotted for the two tests in differentiating rotaviral from bacterial AD. The sensitivity and specificity of M2-PK at optimal cut-off (20 U/g) were 75.9% and 71.4%, respectively. M2-PK and FC had similar values in distinguishing between children with AD caused by rotavirus and Salmonella enteritidis. The performance of both tests in hospitalized patients did not meet the needs of everyday clinical practice. Moreover, no advantage of fecal tests over the measurement of CRP was documented. PMID:24759699