Nuclear localization of Lyn tyrosine kinase mediated by inhibition of its kinase activity

International Nuclear Information System (INIS)

Ikeda, Kikuko; Nakayama, Yuji; Togashi, Yuuki; Obata, Yuuki; Kuga, Takahisa; Kasahara, Kousuke; Fukumoto, Yasunori; Yamaguchi, Naoto

2008-01-01

Src-family kinases, cytoplasmic enzymes that participate in various signaling events, are found at not only the plasma membrane but also subcellular compartments, such as the nucleus, the Golgi apparatus and late endosomes/lysosomes. Lyn, a member of the Src-family kinases, is known to play a role in DNA damage response and cell cycle control in the nucleus. However, it is still unclear how the localization of Lyn to the nucleus is regulated. Here, we investigated the mechanism of the distribution of Lyn between the cytoplasm and the nucleus in epitheloid HeLa cells and hematopoietic THP-1 cells. Lyn was definitely detected in purified nuclei by immunofluorescence and immunoblotting analyses. Nuclear accumulation of Lyn was enhanced upon treatment of cells with leptomycin B (LMB), an inhibitor of Crm1-mediated nuclear export. Moreover, Lyn mutants lacking the sites for lipid modification were highly accumulated in the nucleus upon LMB treatment. Intriguingly, inhibition of the kinase activity of Lyn by SU6656, Csk overexpression, or point mutation in the ATP-binding site induced an increase in nuclear Lyn levels. These results suggest that Lyn being imported into and rapidly exported from the nucleus preferentially accumulates in the nucleus by inhibition of the kinase activity and lipid modification

Tau-Induced Ca2+/Calmodulin-Dependent Protein Kinase-IV Activation Aggravates Nuclear Tau Hyperphosphorylation.

Science.gov (United States)

Wei, Yu-Ping; Ye, Jin-Wang; Wang, Xiong; Zhu, Li-Ping; Hu, Qing-Hua; Wang, Qun; Ke, Dan; Tian, Qing; Wang, Jian-Zhi

2018-04-01

Hyperphosphorylated tau is the major protein component of neurofibrillary tangles in the brains of patients with Alzheimer's disease (AD). However, the mechanism underlying tau hyperphosphorylation is not fully understood. Here, we demonstrated that exogenously expressed wild-type human tau40 was detectable in the phosphorylated form at multiple AD-associated sites in cytoplasmic and nuclear fractions from HEK293 cells. Among these sites, tau phosphorylated at Thr205 and Ser214 was almost exclusively found in the nuclear fraction at the conditions used in the present study. With the intracellular tau accumulation, the Ca 2+ concentration was significantly increased in both cytoplasmic and nuclear fractions. Further studies using site-specific mutagenesis and pharmacological treatment demonstrated that phosphorylation of tau at Thr205 increased nuclear Ca 2+ concentration with a simultaneous increase in the phosphorylation of Ca 2+ /calmodulin-dependent protein kinase IV (CaMKIV) at Ser196. On the other hand, phosphorylation of tau at Ser214 did not significantly change the nuclear Ca 2+ /CaMKIV signaling. Finally, expressing calmodulin-binding protein-4 that disrupts formation of the Ca 2+ /calmodulin complex abolished the okadaic acid-induced tau hyperphosphorylation in the nuclear fraction. We conclude that the intracellular accumulation of phosphorylated tau, as detected in the brains of AD patients, can trigger nuclear Ca 2+ /CaMKIV signaling, which in turn aggravates tau hyperphosphorylation. Our findings provide new insights for tauopathies: hyperphosphorylation of intracellular tau and an increased Ca 2+ concentration may induce a self-perpetuating harmful loop to promote neurodegeneration.

Nuclear pool of phosphatidylinositol 4 phosphate 5 kinase 1α is modified by polySUMO-2 during apoptosis

Energy Technology Data Exchange (ETDEWEB)

Chakrabarti, Rajarshi; Bhowmick, Debajit; Bhargava, Varsha; Bhar, Kaushik; Siddhanta, Anirban, E-mail: asiddhanto@yahoo.com

2013-09-20

Highlights: •Nuclear pool of PIP5K is SUMOylated. •Enhancement of SUMOylated nuclear PIP5K during apoptosis. •Nuclear PIP5K is modified by polySUMO-1 during apoptosis. •Nuclear PIP5K is modified by polySUMO-2 chain during apoptosis. -- Abstract: Phosphatidylinositol 4 phosphate 5 kinase 1α (PIP5K) is mainly localized in the cytosol and plasma membrane. Studies have also indicated its prominent association with nuclear speckles. The exact nature of this nuclear pool of PIP5K is not clear. Using biochemical and microscopic techniques, we have demonstrated that the nuclear pool of PIP5K is modified by SUMO-1 in HEK-293 cells stably expressing PIP5K. Moreover, this SUMOylated pool of PIP5K increased during apoptosis. PolySUMO-2 chain conjugated PIP5K was detected by pull-down experiment using affinity-tagged RNF4, a polySUMO-2 binding protein, during late apoptosis.

Nucleocytoplasmic shuttling of the HSV-2 serine/threonine kinase Us3

International Nuclear Information System (INIS)

Finnen, Renee L.; Johnston, Susan M.; Neron, Casey E.; Banfield, Bruce W.

2011-01-01

The alphaherpesvirus serine/threonine kinase Us3 plays diverse roles in virus multiplication and modifies both nuclear and cytoplasmic substrates. We recently reported that treatment of HSV-2 Us3-transfected and HSV-2-infected cells with leptomycin B, an inhibitor of nuclear export mediated by interaction of chromosomal regional maintenance protein (CRM1) with leucine rich nuclear export signals (NESs), resulted in nuclear trapping of Us3. Here, we utilized fluorescence loss in photobleaching to monitor nuclear export of HSV-2 Us3 and confirm that this process proceeds solely via a CRM1-mediated mechanism. Analysis of deletion derivatives of HSV-2 Us3 fused to a nuclear export reporter protein implicated the involvement of NES-like sequences in nuclear export. However, nuclear trapping of HSV-2 Us3 proteins carrying mutations in these potential NESs was not observed, indicating that these sequences are not functional in the context of full-length protein. Our analyses also revealed previously unidentified regions of HSV-2 Us3 that contribute to its kinase activity.

Protein kinase C-related kinase 1 and 2 play an essential role in thromboxane-mediated neoplastic responses in prostate cancer

OpenAIRE

O'Sullivan, Aine G.; Mulvaney, Eamon P.; Hyland, Paula B.; Kinsella, B. Therese

2015-01-01

The prostanoid thromboxane (TX) A2 is increasingly implicated in neoplastic progression, including prostate cancer (PCa). Mechanistically, we recently identified protein kinase C-related kinase (PRK) 1 as a functional interactant of both the TP? and TP? isoforms of the human T prostanoid receptor (TP). The interaction with PRK1 was not only essential for TP?/TP?-induced PCa cell migration but also enabled the TXA2-TP axis to induce phosphorylation of histone H3 at Thr11 (H3Thr11), an epigenet...

Parkinson-Related LRRK2 Mutation R1628P Enables Cdk5 Phosphorylation of LRRK2 and Upregulates Its Kinase Activity.

Directory of Open Access Journals (Sweden)

Yang Shu

Full Text Available Recent studies have linked certain single nucleotide polymorphisms in the leucine-rich repeat kinase 2 (LRRK2 gene with Parkinson's disease (PD. Among the mutations, LRRK2 c.4883G>C (R1628P variant was identified to have a significant association with the risk of PD in ethnic Han-Chinese populations. But the molecular pathological mechanisms of R1628P mutation in PD is still unknown.Unlike other LRRK2 mutants in the Roc-COR-Kinase domain, the R1628P mutation didn't alter the LRRK2 kinase activity and promote neuronal death directly. LRRK2 R1628P mutation increased the binding affinity of LRRK2 with Cyclin-dependent kinase 5 (Cdk5. Interestingly, R1628P mutation turned its adjacent amino acid residue S1627 on LRRK2 protein to a novel phosphorylation site of Cdk5, which could be defined as a typical type II (+ phosphorylation-related single nucleotide polymorphism. Importantly, we showed that the phosphorylation of S1627 by Cdk5 could activate the LRRK2 kinase, and neurons ectopically expressing R1628P displayed a higher sensitivity to 1-methyl-4-phenylpyridinium, a bioactive metabolite of environmental toxin MPTP, in a Cdk5-dependent manner.Our data indicate that Parkinson-related LRRK2 mutation R1628P leads to Cdk5 phosphorylation of LRRK2 at S1627, which would upregulate the kinase activity of LRRK2 and consequently cause neuronal death.

Design basis flood for nuclear power plants on river sites

International Nuclear Information System (INIS)

1983-01-01

The Guide presents techniques for determining the design basis flood (DBF) to be used for siting nuclear power plants at or near non-tidal reaches of rivers and for protecting nuclear power plants against floods. Since flooding of a nuclear power plant can have repercussions on safety, the DBF is always chosen to have a very low probability of exceedance per annum. The DBF may result from one or more of the following causes: (1) Precipitation, snowmelt; (2) Failure of water control structures, either from seismic or hydrological causes or from faulty operation of these structures; (3) Channel obstruction such as landslide, ice effects, log or debris jams, and effects of vulcanism. Normally the DBF is not less than any recorded or historical flood occurrence. For flood evaluation two types of methods are discussed in this Guide: probabilistic and deterministic. Simple probabilistic methods to determine floods of such low exceedance probability have a great degree of uncertainty and are presented for use only during the site survey. However, the more sophisticated probabilistic methods, the so-called stochastic methods, may give an acceptable result, as outlined in this Guide. The preferred method of evaluating the component of the DBF due to precipitation, as described in this Guide, is the deterministic one, based on the concept of a limit to the probable maximum precipitation (PMP) and on the unit hydrograph technique. Dam failures may generate a flood substantially more severe than that due to precipitation. The methodology for evaluating these types of floods is therefore presented in this Guide. Making allowance for the possible simultaneous occurrence of two or more important flood-producing events is also discussed here. The Guide does not deal with floods caused by sabotage

Cdc7 kinase - a new target for drug development.

Science.gov (United States)

Swords, Ronan; Mahalingam, Devalingam; O'Dwyer, Michael; Santocanale, Corrado; Kelly, Kevin; Carew, Jennifer; Giles, Francis

2010-01-01

The cell division cycle 7 (Cdc7) is a serine threonine kinase that is of critical importance in the regulation of normal cell cycle progression. Cdc7 kinase is highly conserved during evolution and much has been learned about its biological roles in humans through the study of lower eukaryotes, particularly yeasts. Two important regulator proteins, Dbf4 and Drf1, bind to and modulate the kinase activity of human Cdc7 which phosphorylates several sites on Mcm2 (minichromosome maintenance protein 2), one of the six subunits of the replicative DNA helicase needed for duplication of the genome. Through regulation of both DNA synthesis and DNA damage response, both key functions in the survival of tumour cells, Cdc7 becomes an attractive target for pharmacological inhibition. There are much data available on the pre-clinical anti-cancer effects of Cdc7 depletion and although there are no available Cdc7 inhibitors in clinical trials as yet, several lead compounds are being optimised for this purpose. In this review, we will address the current status of Cdc7 as an important target for new drug development.

Protein kinase A antagonist inhibits β-catenin nuclear translocation, c-Myc and COX-2 expression and tumor promotion in ApcMin/+ mice

Directory of Open Access Journals (Sweden)

Brudvik Kristoffer W

2011-12-01

Full Text Available Abstract Background The adenomatous polyposis coli (APC protein is part of the destruction complex controlling proteosomal degradation of β-catenin and limiting its nuclear translocation, which is thought to play a gate-keeping role in colorectal cancer. The destruction complex is inhibited by Wnt-Frz and prostaglandin E2 (PGE2 - PI-3 kinase pathways. Recent reports show that PGE2-induced phosphorylation of β-catenin by protein kinase A (PKA increases nuclear translocation indicating two mechanisms of action of PGE2 on β-catenin homeostasis. Findings Treatment of ApcMin/+ mice that spontaneously develop intestinal adenomas with a PKA antagonist (Rp-8-Br-cAMPS selectively targeting only the latter pathway reduced tumor load, but not the number of adenomas. Immunohistochemical characterization of intestines from treated and control animals revealed that expression of β-catenin, β-catenin nuclear translocation and expression of the β-catenin target genes c-Myc and COX-2 were significantly down-regulated upon Rp-8-Br-cAMPS treatment. Parallel experiments in a human colon cancer cell line (HCT116 revealed that Rp-8-Br-cAMPS blocked PGE2-induced β-catenin phosphorylation and c-Myc upregulation. Conclusion Based on our findings we suggest that PGE2 act through PKA to promote β-catenin nuclear translocation and tumor development in ApcMin/+ mice in vivo, indicating that the direct regulatory effect of PKA on β-catenin nuclear translocation is operative in intestinal cancer.

Nucleoporin 62 and Ca(2+)/calmodulin dependent kinase kinase 2 regulate androgen receptor activity in castrate resistant prostate cancer cells.

Science.gov (United States)

Karacosta, Loukia G; Kuroski, Laura A; Hofmann, Wilma A; Azabdaftari, Gissou; Mastri, Michalis; Gocher, Angela M; Dai, Shuhang; Hoste, Allen J; Edelman, Arthur M

2016-02-15

Re-activation of the transcriptional activity of the androgen receptor (AR) is an important factor mediating progression from androgen-responsive to castrate-resistant prostate cancer (CRPC). However, the mechanisms regulating AR activity in CRPC remain incompletely understood. Ca(2+) /calmodulin-dependent kinase kinase (CaMKK) 2 was previously shown to regulate AR activity in androgen-responsive prostate cancer cells. Our objective was to further explore the basis of this regulation in CRPC cells. The abundance of CaMKK2 in nuclear fractions of androgen-responsive prostate cancer and CRPC, cells were determined by subcellular fractionation and Western blotting. CaMKK2 association with nuclear pore complexes (NPCs) and nucleoporins (Nups) including Nup62, were imaged by structured illumination and super-resolution fluorescence microscopy and co-immunoprecipitation, respectively. The abundance and subcellular localization of CaMKK2 and Nup62 in human clinical specimens of prostate cancer was visualized by immunohistochemistry. The role of Nups in the growth and viability of CRPC cells was assessed by RNA interference and cell counting. The involvement of CaMKK2 and Nup62 in regulating AR transcriptional activity was addressed by RNA interference, chromatin immunoprecipitation, androgen response element reporter assay, and Western blotting. CaMKK2 was expressed at higher levels in the nuclear fraction of CPRC C4-2 cells, than in that of androgen-responsive LNCaP cells. In C4-2 cells, CaMKK2 associated with NPCs of the nuclear envelope and physically interacted with Nup62. CaMKK2 and Nup62 demonstrated pronounced, and similar increases in both expression and perinuclear/nuclear localization in human clinical specimens of advanced prostate cancer relative to normal prostate. Knockdown of Nup62, but not of Nups, 98 or 88, reduced growth and viability of C4-2 cells. Knockdown of Nup62 produced a greater reduction of the growth and viability of C4-2 cells than of non

Tannase production by Aspergillus aculeatus DBF9 through solid-state fermentation.

Science.gov (United States)

Banerjee, D; Mondal, K C; Pati, B R

2007-06-01

Tannase an industrially important enzyme was produced by Aspergillus aculeatus DBF9 through a solid-state fermentation (SSF). The organism produced good amount of enzyme and gallic acid in wheat bran among the solid substrate used in SSF. Maximum enzyme and gallic acid production occurred in 5% tannic acid after 72 h. Eighty percent initial substrate moisture and 30 degrees C temperature was found suitable for tannase production.

Fasting Induces Nuclear Factor E2-Related Factor 2 and ATP-Binding Cassette Transporters via Protein Kinase A and Sirtuin-1 in Mouse and Human

Science.gov (United States)

Kulkarni, Supriya R.; Donepudi, Ajay C.; Xu, Jialin; Wei, Wei; Cheng, Qiuqiong C.; Driscoll, Maureen V.; Johnson, Delinda A.; Johnson, Jeffrey A.; Li, Xiaoling

2014-01-01

Abstract Aims: The purpose of this study was to determine whether 3′-5′-cyclic adenosine monophosphate (cAMP)-protein kinase A (PKA) and Sirtuin-1 (SIRT1) dependent mechanisms modulate ATP-binding Cassette (ABC) transport protein expression. ABC transport proteins (ABCC2–4) are essential for chemical elimination from hepatocytes and biliary excretion. Nuclear factor-E2 related-factor 2 (NRF2) is a transcription factor that mediates ABCC induction in response to chemical inducers and liver injury. However, a role for NRF2 in the regulation of transporter expression in nonchemical models of liver perturbation is largely undescribed. Results: Here we show that fasting increased NRF2 target gene expression through NRF2- and SIRT1–dependent mechanisms. In intact mouse liver, fasting induces NRF2 target gene expression by at least 1.5 to 5-fold. In mouse and human hepatocytes, treatment with 8-Bromoadenosine-cAMP, a cAMP analogue, increased NRF2 target gene expression and antioxidant response element activity, which was decreased by the PKA inhibitor, H-89. Moreover, fasting induced NRF2 target gene expression was decreased in liver and hepatocytes of SIRT1 liver-specific null mice and NRF2-null mice. Lastly, NRF2 and SIRT1 were recruited to MAREs and Antioxidant Response Elements (AREs) in the human ABCC2 promoter. Innovation: Oxidative stress mediated NRF2 activation is well described, yet the influence of basic metabolic processes on NRF2 activation is just emerging. Conclusion: The current data point toward a novel role of nutrient status in regulation of NRF2 activity and the antioxidant response, and indicates that cAMP/PKA and SIRT1 are upstream regulators for fasting-induced activation of the NRF2-ARE pathway. Antioxid. Redox Signal. 20, 15–30. PMID:23725046

Pea DNA topoisomerase I is phosphorylated and stimulated by casein kinase 2 and protein kinase C.

Science.gov (United States)

Tuteja, Narendra; Reddy, Malireddy Kodandarami; Mudgil, Yashwanti; Yadav, Badam Singh; Chandok, Meena Rani; Sopory, Sudhir Kumar

2003-08-01

DNA topoisomerase I catalyzes the relaxation of superhelical DNA tension and is vital for DNA metabolism; therefore, it is essential for growth and development of plants. Here, we have studied the phosphorylation-dependent regulation of topoisomerase I from pea (Pisum sativum). The purified enzyme did not show autophosphorylation but was phosphorylated in an Mg(2+)-dependent manner by endogenous protein kinases present in pea nuclear extracts. This phosphorylation was abolished with calf intestinal alkaline phosphatase and lambda phosphatase. It was also phosphorylated by exogenous casein kinase 2 (CK2), protein kinase C (PKC; from animal sources), and an endogenous pea protein, which was purified using a novel phorbol myristate acetate affinity chromatography method. All of these phosphorylations were inhibited by heparin (inhibitor of CK2) and calphostin (inhibitor of PKC), suggesting that pea topoisomerase I is a bona fide substrate for these kinases. Spermine and spermidine had no effect on the CK2-mediated phosphorylation, suggesting that it is polyamine independent. Phospho-amino acid analysis showed that only serine residues were phosphorylated, which was further confirmed using antiphosphoserine antibody. The topoisomerase I activity increased after phosphorylation with exogenous CK2 and PKC. This study shows that these kinases may contribute to the physiological regulation of DNA topoisomerase I activity and overall DNA metabolism in plants.

A novel, non-canonical mechanism of regulation of MST3 (mammalian Sterile20-related kinase 3)

OpenAIRE

Fuller, Stephen J; McGuffin, Liam J; Marshall, Andrew K; Giraldo, Alejandro; Pikkarainen, Sampsa; Clerk, Angela; Sugden, Peter

2012-01-01

The canonical pathway of regulation of the GCK (germinal centre kinase) III subgroup member, MST3 (mammalian Sterile20-related kinase 3), involves a caspase-mediated cleavage between N-terminal catalytic and C-terminal regulatory domains with possible concurrent autophosphorylation of the activation loop MST3(Thr178), induction of serine/threonine protein kinase activity and nuclear localization. We identified an alternative ‘non-canonical’ pathway of MST3 activation (regulated primarily thro...

The Hsk1(Cdc7) Replication Kinase Regulates Origin Efficiency

OpenAIRE

Patel, Prasanta K.; Kommajosyula, Naveen; Rosebrock, Adam; Bensimon, Aaron; Leatherwood, Janet; Bechhoefer, John; Rhind, Nicholas

2008-01-01

Origins of DNA replication are generally inefficient, with most firing in fewer than half of cell cycles. However, neither the mechanism nor the importance of the regulation of origin efficiency is clear. In fission yeast, origin firing is stochastic, leading us to hypothesize that origin inefficiency and stochasticity are the result of a diffusible, rate-limiting activator. We show that the Hsk1-Dfp1 replication kinase (the fission yeast Cdc7-Dbf4 homologue) plays such a role. Increasing or ...

Caloric Restriction Mimetic 2-Deoxyglucose Alleviated Inflammatory Lung Injury via Suppressing Nuclear Pyruvate Kinase M2-Signal Transducer and Activator of Transcription 3 Pathway.

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Hu, Kai; Yang, Yongqiang; Lin, Ling; Ai, Qing; Dai, Jie; Fan, Kerui; Ge, Pu; Jiang, Rong; Wan, Jingyuan; Zhang, Li

2018-01-01

Inflammation is an energy-intensive process, and caloric restriction (CR) could provide anti-inflammatory benefits. CR mimetics (CRM), such as the glycolytic inhibitor 2-deoxyglucose (2-DG), mimic the beneficial effects of CR without inducing CR-related physiologic disturbance. This study investigated the potential anti-inflammatory benefits of 2-DG and the underlying mechanisms in mice with lipopolysaccharide (LPS)-induced lethal endotoxemia. The results indicated that pretreatment with 2-DG suppressed LPS-induced elevation of tumor necrosis factor alpha and interleukin 6. It also suppressed the upregulation of myeloperoxidase, attenuated Evans blue leakage, alleviated histological abnormalities in the lung, and improved the survival of LPS-challenged mice. Treatment with 2-DG had no obvious effects on the total level of pyruvate kinase M2 (PKM2), but it significantly suppressed LPS-induced elevation of PKM2 in the nuclei. Prevention of PKM2 nuclear accumulation by ML265 mimicked the anti-inflammatory benefits of 2-DG. In addition, treatment with 2-DG or ML265 suppressed the phosphorylation of nuclear signal transducer and activator of transcription 3 (STAT3). Inhibition of STAT3 by stattic suppressed LPS-induced inflammatory injury. Interestingly, posttreatment with 2-DG at the early stage post-LPS challenge also improved the survival of the experimental animals. This study found that treatment with 2-DG, a representative CRM, provided anti-inflammatory benefits in lethal inflammation. The underlying mechanisms included suppressed nuclear PKM2-STAT3 pathway. These data suggest that 2-DG might have potential value in the early intervention of lethal inflammation.

Multi-lobulation of the nucleus in prolonged S phase by nuclear expression of Chk tyrosine kinase.

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Nakayama, Yuji; Yamaguchi, Naoto

2005-04-01

Chk tyrosine kinase phosphorylates Src-family tyrosine kinases and suppresses their kinase activity. We recently showed that Chk localizes to the nucleus as well as the cytoplasm and inhibits cell proliferation. To investigate the role of nuclear Chk in proliferation, various Chk mutants were constructed and expressed. Nuclear localization of Chk-induced dynamic multi-lobulation of the nucleus and prolonged S phase of the cell cycle. The N-terminal domain of Chk and a portion of its kinase domain but not the kinase activity were responsible for induction of the multi-lobulation. Cell sorting analysis revealed that nuclear multi-lobulated cells were enriched in late S phase. Multi-lobulated nuclei were surrounded with lamin B1 that was particularly concentrated in concave regions of the nuclei. Furthermore, treatment with nocodazole or taxol disrupted multi-lobulation of the nucleus. These results suggest that nuclear multi-lobulation in late S phase, which is dependent on polymerization and depolymerization of microtubules, may be involved in nuclear Chk-induced inhibition of proliferation.

Multi-lobulation of the nucleus in prolonged S phase by nuclear expression of Chk tyrosine kinase

International Nuclear Information System (INIS)

Nakayama, Yuji; Yamaguchi, Naoto

2005-01-01

Chk tyrosine kinase phosphorylates Src-family tyrosine kinases and suppresses their kinase activity. We recently showed that Chk localizes to the nucleus as well as the cytoplasm and inhibits cell proliferation. To investigate the role of nuclear Chk in proliferation, various Chk mutants were constructed and expressed. Nuclear localization of Chk-induced dynamic multi-lobulation of the nucleus and prolonged S phase of the cell cycle. The N-terminal domain of Chk and a portion of its kinase domain but not the kinase activity were responsible for induction of the multi-lobulation. Cell sorting analysis revealed that nuclear multi-lobulated cells were enriched in late S phase. Multi-lobulated nuclei were surrounded with lamin B1 that was particularly concentrated in concave regions of the nuclei. Furthermore, treatment with nocodazole or taxol disrupted multi-lobulation of the nucleus. These results suggest that nuclear multi-lobulation in late S phase, which is dependent on polymerization and depolymerization of microtubules, may be involved in nuclear Chk-induced inhibition of proliferation

Purification and characterization of a casein kinase 2-type protein kinase from pea nuclei

Science.gov (United States)

Li, H.; Roux, S. J.

1992-01-01

Almost all the polyamine-stimulated protein kinase activity associated with the chromatin fraction of nuclei purified from etiolated pea (Pisum sativum L.) plumules is present in a single enzyme that can be extracted from chromatin by 0.35 molar NaCl. This protein kinase can be further purified over 2000-fold by salt fractionation and anion-exchange and casein-agarose column chromatography, after which it is more than 90% pure. The purified kinase has a specific activity of about 650 nanomoles per minute per milligram protein in the absence of polyamines, with either ATP or GTP as phosphoryl donor. Spermidine can stimulate its activity fourfold, with half-maximal activation at about 2 millimolar. Spermine and putrescine also stimulate activity, although somewhat less effectively. This kinase has a tetrameric alpha 2 beta 2 structure with a native molecular weight of 130,000, and subunit molecular weights of 36,000 for the catalytic subunit (alpha) and 29,000 for the regulatory subunit (beta). In western blot analyses, only the alpha subunit reacts strongly with polyclonal antibodies to a Drosophila casein kinase II. The pea kinase can use casein and phosvitin as artificial substrates, phosphorylating both the serine and threonine residues of casein. It has a pH optimum near 8.0, a Vmax of 1.5 micromoles per minute per milligram protein, and a Km for ATP of approximately 75 micromolar. Its activity can be almost completely inhibited by heparin at 5 micrograms per milliliter, but is relatively insensitive to concentrations of staurosporine, K252a, and chlorpromazine that strongly antagonize Ca(2+) -regulated protein kinases. These results are discussed in relation to recent findings that casein kinase 2-type kinases may phosphorylate trans-acting factors that bind to light-regulated promoters in plants.

Caloric Restriction Mimetic 2-Deoxyglucose Alleviated Inflammatory Lung Injury via Suppressing Nuclear Pyruvate Kinase M2–Signal Transducer and Activator of Transcription 3 Pathway

Directory of Open Access Journals (Sweden)

Kai Hu

2018-03-01

Full Text Available Inflammation is an energy-intensive process, and caloric restriction (CR could provide anti-inflammatory benefits. CR mimetics (CRM, such as the glycolytic inhibitor 2-deoxyglucose (2-DG, mimic the beneficial effects of CR without inducing CR-related physiologic disturbance. This study investigated the potential anti-inflammatory benefits of 2-DG and the underlying mechanisms in mice with lipopolysaccharide (LPS-induced lethal endotoxemia. The results indicated that pretreatment with 2-DG suppressed LPS-induced elevation of tumor necrosis factor alpha and interleukin 6. It also suppressed the upregulation of myeloperoxidase, attenuated Evans blue leakage, alleviated histological abnormalities in the lung, and improved the survival of LPS-challenged mice. Treatment with 2-DG had no obvious effects on the total level of pyruvate kinase M2 (PKM2, but it significantly suppressed LPS-induced elevation of PKM2 in the nuclei. Prevention of PKM2 nuclear accumulation by ML265 mimicked the anti-inflammatory benefits of 2-DG. In addition, treatment with 2-DG or ML265 suppressed the phosphorylation of nuclear signal transducer and activator of transcription 3 (STAT3. Inhibition of STAT3 by stattic suppressed LPS-induced inflammatory injury. Interestingly, posttreatment with 2-DG at the early stage post-LPS challenge also improved the survival of the experimental animals. This study found that treatment with 2-DG, a representative CRM, provided anti-inflammatory benefits in lethal inflammation. The underlying mechanisms included suppressed nuclear PKM2-STAT3 pathway. These data suggest that 2-DG might have potential value in the early intervention of lethal inflammation.

Helicobacter pylori induces cell migration and invasion through casein kinase 2 in gastric epithelial cells.

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Lee, Yeo Song; Lee, Do Yeon; Yu, Da Yeon; Kim, Shin; Lee, Yong Chan

2014-12-01

Chronic infection with Helicobacter pylori (H. pylori) is causally linked with gastric carcinogenesis. Virulent H. pylori strains deliver bacterial CagA into gastric epithelial cells. Induction of high motility and an elongated phenotype is considered to be CagA-dependent process. Casein kinase 2 plays a critical role in carcinogenesis through signaling pathways related to the epithelial mesenchymal transition. This study was aimed to investigate the effect of H. pylori infection on the casein kinase 2-mediated migration and invasion in gastric epithelial cells. AGS or MKN28 cells as human gastric epithelial cells and H. pylori strains Hp60190 (ATCC 49503, CagA(+)) and Hp8822 (CagA(-)) were used. Cells were infected with H. pylori at multiplicity of infection of 100 : 1 for various times. We measured in vitro kinase assay to examine casein kinase 2 activity and performed immunofluorescent staining to observe E-cadherin complex. We also examined β-catenin transactivation through promoter assay and MMP7 expression by real-time PCR and ELISA. H. pylori upregulates casein kinase 2 activity and inhibition of casein kinase 2 in H. pylori-infected cells profoundly suppressed cell invasiveness and motility. We confirmed that casein kinase 2 mediates membranous α-catenin depletion through dissociation of the α-/β-catenin complex in H. pylori-infected cells. We also found that H. pylori induces β-catenin nuclear translocation and increases MMP7 expressions mediated through casein kinase 2. We show for the first time that CagA(+) H. pylori upregulates cellular invasiveness and motility through casein kinase 2. The demonstration of a mechanistic interplay between H. pylori and casein kinase 2 provides important insights into the role of CagA(+) H. pylori in the gastric cancer invasion and metastasis. © 2014 John Wiley & Sons Ltd.

Oryza sativa (Rice) Hull Extract Inhibits Lipopolysaccharide-Induced Inflammatory Response in RAW264.7 Macrophages by Suppressing Extracellular Signal-regulated Kinase, c-Jun N-terminal Kinase, and Nuclear Factor-κB Activation.

Science.gov (United States)

Ha, Sang Keun; Sung, Jeehye; Choi, Inwook; Kim, Yoonsook

2016-01-01

Rice ( Oryza sativa ) is a major cereal crop in many Asian countries and an important staple food source. Rice hulls have been reported to possess antioxidant activities. In this study, we evaluated the antiinflammatory effects of rice hull extract and associated signal transduction mechanisms in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. We found that rice hull extract inhibited nitric oxide (NO) and prostaglandin E 2 by suppressing the expression of inducible NO synthase and cyclooxygenase-2, respectively. The release of interleukin-1β and tumor necrosis factor-α was also reduced in a dose-dependent manner. Furthermore, rice hull extract attenuated the activation of nuclear factor-kappa B (NF-κB), as well as the phosphorylation of mitogen-activated protein kinases, extracellular signal-regulated kinase (ERK), and c-Jun N-terminal kinase (JNK), in LPS-stimulated RAW264.7 cells. This suggests that rice hull extract decreases the production of inflammatory mediators by downregulating ERK and JNK and the NF-κB signal pathway in RAW 264.7 cells. Rice hull extract inhibits the lipopolysaccharide-induced inflammatory response in RAW264.7 macrophages.Rice hull extract inhibited nitric oxide and prostaglandin E 2 by suppressing the expression of inducible NO synthase and cyclooxygenase-2, respectively.Rice hull extract exerted anti-inflammatory effect through inhibition of nuclear factor-kappa B, extracellular signal-regulated kinase and c-Jun N-terminal kinase signaling pathways.Rice hull extract may provide a potential therapeutic approach for inflammatory diseases. Abbreviations used: COX-2: cyclooxygenase-2, ERK: extracellular signal-regulated kinase, IκB: inhibitory kappa B, IL-1β: interleukin-1β, iNOS: inducible NO synthase, JNK: c-Jun N-terminal kinase, LPS: lipopolysaccharide, MAPKs: mitogen-activated protein kinases, NF-κB: nuclear factor-κB, NO: nitric oxide, PGE2: prostaglandin E2, RHE: rice hull extract, ROS: reactive oxygen species

Hemistepsin A ameliorates acute inflammation in macrophages via inhibition of nuclear factor-κB and activation of nuclear factor erythroid 2-related factor 2.

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Kim, Jae Kwang; Lee, Ji Eun; Jung, Eun Hye; Jung, Ji Yun; Jung, Dae Hwa; Ku, Sae Kwang; Cho, Il Je; Kim, Sang Chan

2018-01-01

Hemistepsin A (HsA) is a sesquiterpene lactone isolated from Hemistepta lyrata (Bunge) Bunge. We investigated the anti-inflammatory effects of HsA and sought to determine its mechanisms of action in macrophages. HsA pretreatment inhibited nitric oxide production, and reduced the expression of iNOS and COX-2 in Toll-like receptor ligand-stimulated RAW 264.7 cells. Additionally, HsA decreased the secretion of proinflammatory cytokines in lipopolysaccharide (LPS)-stimulated Kupffer cells as well as in RAW 264.7 cells. HsA inhibited phosphorylation of IKKα/β and degradation of IκBα, resulting in decreased nuclear translocation of nuclear factor-κB (NF-κB) and its transcriptional activity. Moreover, HsA phosphorylated nuclear factor erythroid 2-related factor 2 (Nrf2), increased expression levels of antioxidant genes, and attenuated LPS-stimulated H 2 O 2 production. Phosphorylation of p38 and c-Jun N-terminal kinase was required for HsA-mediated Nrf2 phosphorylation. In a D-galactosamine/LPS-induced liver injury model, HsA ameliorated D-galactosamine/LPS-induced hepatocyte degeneration and inflammatory cells infiltration. Moreover, immunohistochemical analyses using nitrotyrosine, 4-hydroxynonenal, and cleaved poly (ADP-ribose) polymerase antibodies revealed that HsA protected the liver from oxidative stress. Furthermore, HsA reduced the numbers of proinflammatory cytokine-positive cells in hepatic tissues. Thus, these results suggest HsA may be a promising natural product to manage inflammation-mediated tissue injuries through inhibition of NF-κB and activation of Nrf2. Copyright © 2017 Elsevier Ltd. All rights reserved.

AMP kinase-related kinase NUAK2 affects tumor growth, migration, and clinical outcome of human melanoma.

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Namiki, Takeshi; Tanemura, Atsushi; Valencia, Julio C; Coelho, Sergio G; Passeron, Thierry; Kawaguchi, Masakazu; Vieira, Wilfred D; Ishikawa, Masashi; Nishijima, Wataru; Izumo, Toshiyuki; Kaneko, Yasuhiko; Katayama, Ichiro; Yamaguchi, Yuji; Yin, Lanlan; Polley, Eric C; Liu, Hongfang; Kawakami, Yutaka; Eishi, Yoshinobu; Takahashi, Eishi; Yokozeki, Hiroo; Hearing, Vincent J

2011-04-19

The identification of genes that participate in melanomagenesis should suggest strategies for developing therapeutic modalities. We used a public array comparative genomic hybridization (CGH) database and real-time quantitative PCR (qPCR) analyses to identify the AMP kinase (AMPK)-related kinase NUAK2 as a candidate gene for melanomagenesis, and we analyzed its functions in melanoma cells. Our analyses had identified a locus at 1q32 where genomic gain is strongly associated with tumor thickness, and we used real-time qPCR analyses and regression analyses to identify NUAK2 as a candidate gene at that locus. Associations of relapse-free survival and overall survival of 92 primary melanoma patients with NUAK2 expression measured using immunohistochemistry were investigated using Kaplan-Meier curves, log rank tests, and Cox regression models. Knockdown of NUAK2 induces senescence and reduces S-phase, decreases migration, and down-regulates expression of mammalian target of rapamycin (mTOR). In vivo analysis demonstrated that knockdown of NUAK2 suppresses melanoma tumor growth in mice. Survival analysis showed that the risk of relapse is greater in acral melanoma patients with high levels of NUAK2 expression than in acral melanoma patients with low levels of NUAK2 expression (hazard ratio = 3.88; 95% confidence interval = 1.44-10.50; P = 0.0075). These data demonstrate that NUAK2 expression is significantly associated with the oncogenic features of melanoma cells and with the survival of acral melanoma patients. NUAK2 may provide a drug target to suppress melanoma progression. This study further supports the importance of NUAK2 in cancer development and tumor progression, while AMPK has antioncogenic properties.

Peptide substrates for Rho-associated kinase 2 (Rho-kinase 2/ROCK2.

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Jeong-Hun Kang

Full Text Available Peptide substrates sensitive for a certain protein kinase could be important for new-drug development and to understand the mechanism of diseases. Rho-associated kinase (Rho-kinase/ROCK is a serine/threonine kinase, and plays an important part in cardiovascular disease, migration and invasion of tumor cells, and in neurological disorders. The purpose of this study was to find substrates with high affinity and sensitivity for ROCK2. We synthesized 136 peptide substrates from protein substrates for ROCK2 with different lengths and charged peptides. Incorporation of (32P [counts per minute (CPM] for each peptide substrate was determined by the radiolabel assay using [γ-(32P]ATP. When the top five peptide substrates showing high CPMs (R4, R22, R133, R134, and R135 were phosphorylated by other enzymes (PKA, PKCα, and ERK1, R22, R133, and R135 displayed the highest CPM level for ROCK2 compared with other enzymes, whereas R4 and R134 showed similar CPM levels for ROCK2 and PKCα. We hypothesize that R22, R133, and R135 can be useful peptide substrates for ROCK2.

Ribosomal S6 Kinase Cooperates with Casein Kinase 2 to Modulate the Drosophila Circadian Molecular Oscillator

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Akten, Bikem; Tangredi, Michelle M.; Jauch, Eike; Roberts, Mary A.; Ng, Fanny; Raabe, Thomas; Jackson, F. Rob

2009-01-01

There is a universal requirement for post-translational regulatory mechanisms in circadian clock systems. Previous work in Drosophila has identified several kinases, phosphatases and an E3 ligase that are critical for determining the nuclear translocation and/or stability of clock proteins. The present study evaluated the function of p90 ribosomal S6 kinase (RSK) in the Drosophila circadian system. In mammals, RSK1 is a light- and clock-regulated kinase known to be activated by the MAPK pathway, but there is no direct evidence that it functions as a component of the circadian system. Here, we show that Drosophila S6KII RNA displays rhythms in abundance, indicative of circadian control. Importantly, an S6KII null mutant exhibits a short-period circadian phenotype that can be rescued by expression of the wild-type gene in clock neurons, indicating a role for S6KII in the molecular oscillator. Peak PER clock protein expression is elevated in the mutant, indicative of enhanced stability, whereas per mRNA level is decreased, consistent with enhanced feedback repression. Gene reporter assays show that decreased S6KII is associated with increased PER repression. Surprisingly, we demonstrate a physical interaction between S6KII and the Casein Kinase 2 regulatory subunit (CK2β), suggesting a functional relationship between the two kinases. In support of such a relationship, there are genetic interactions between S6KII and CK2 mutations, in vivo, which indicate that CK2 activity is required for S6KII action. We propose that the two kinases cooperate within clock neurons to fine-tune circadian period, improving the precision of the clock mechanism. PMID:19144847

SNF1-related protein kinases 2 are negatively regulated by a plant-specific calcium sensor.

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Bucholc, Maria; Ciesielski, Arkadiusz; Goch, Grażyna; Anielska-Mazur, Anna; Kulik, Anna; Krzywińska, Ewa; Dobrowolska, Grażyna

2011-02-04

SNF1-related protein kinases 2 (SnRK2s) are plant-specific enzymes involved in environmental stress signaling and abscisic acid-regulated plant development. Here, we report that SnRK2s interact with and are regulated by a plant-specific calcium-binding protein. We screened a Nicotiana plumbaginifolia Matchmaker cDNA library for proteins interacting with Nicotiana tabacum osmotic stress-activated protein kinase (NtOSAK), a member of the SnRK2 family. A putative EF-hand calcium-binding protein was identified as a molecular partner of NtOSAK. To determine whether the identified protein interacts only with NtOSAK or with other SnRK2s as well, we studied the interaction of an Arabidopsis thaliana orthologue of the calcium-binding protein with selected Arabidopsis SnRK2s using a two-hybrid system. All kinases studied interacted with the protein. The interactions were confirmed by bimolecular fluorescence complementation assay, indicating that the binding occurs in planta, exclusively in the cytoplasm. Calcium binding properties of the protein were analyzed by fluorescence spectroscopy using Tb(3+) as a spectroscopic probe. The calcium binding constant, determined by the protein fluorescence titration, was 2.5 ± 0.9 × 10(5) M(-1). The CD spectrum indicated that the secondary structure of the protein changes significantly in the presence of calcium, suggesting its possible function as a calcium sensor in plant cells. In vitro studies revealed that the activity of SnRK2 kinases analyzed is inhibited in a calcium-dependent manner by the identified calcium sensor, which we named SCS (SnRK2-interacting calcium sensor). Our results suggest that SCS is involved in response to abscisic acid during seed germination most probably by negative regulation of SnRK2s activity.

Regulation of p53, nuclear factor κB and cyclooxygenase-2 expression by bromelain through targeting mitogen-activated protein kinase pathway in mouse skin

International Nuclear Information System (INIS)

Kalra, Neetu; Bhui, Kulpreet; Roy, Preeti; Srivastava, Smita; George, Jasmine; Prasad, Sahdeo; Shukla, Yogeshwer

2008-01-01

Bromelain is a pharmacologically active compound, present in stems and immature fruits of pineapples (Ananas cosmosus), which has been shown to have anti-edematous, anti-inflammatory, anti-thrombotic and anti-metastatic properties. In the present study, antitumorigenic activity of bromelain was recorded in 7,12-dimethylbenz(a)anthracene (DMBA)-initiated and 12-O-tetradecanoylphorbol-13-acetate (TPA)-promoted 2-stage mouse skin model. Results showed that bromelain application delayed the onset of tumorigenesis and reduced the cumulative number of tumors, tumor volume and the average number of tumors/mouse. To establish a cause and effect relationship, we targeted the proteins involved in the cell death pathway. Bromelain treatment resulted in upregulation of p53 and Bax and subsequent activation of caspase 3 and caspase 9 with concomitant decrease in antiapoptotic protein Bcl-2 in mouse skin. Since persistent induction of cyclooxygenase-2 (Cox-2) is frequently implicated in tumorigenesis and is regulated by nuclear factor-kappa B (NF-κB), we also investigated the effect of bromelain on Cox-2 and NF-κB expression. Results showed that bromelain application significantly inhibited Cox-2 and inactivated NF-κB by blocking phosphorylation and subsequent degradation of IκBα. In addition, bromelain treatment attenuated DMBA-TPA-induced phosphorylation of extracellular signal-regulated protein kinase (ERK1/2), mitogen-activated protein kinase (MAPK) and Akt. Taken together, we conclude that bromelain induces apoptosis-related proteins along with inhibition of NF-κB-driven Cox-2 expression by blocking the MAPK and Akt/protein kinase B signaling in DMBA-TPA-induced mouse skin tumors, which may account for its anti-tumorigenic effects

Light-induced conformational changes of LOV1 (light oxygen voltage-sensing domain 1) and LOV2 relative to the kinase domain and regulation of kinase activity in Chlamydomonas phototropin.

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Okajima, Koji; Aihara, Yusuke; Takayama, Yuki; Nakajima, Mihoko; Kashojiya, Sachiko; Hikima, Takaaki; Oroguchi, Tomotaka; Kobayashi, Amane; Sekiguchi, Yuki; Yamamoto, Masaki; Suzuki, Tomomi; Nagatani, Akira; Nakasako, Masayoshi; Tokutomi, Satoru

2014-01-03

Phototropin (phot), a blue light (BL) receptor in plants, has two photoreceptive domains named LOV1 and LOV2 as well as a Ser/Thr kinase domain (KD) and acts as a BL-regulated protein kinase. A LOV domain harbors a flavin mononucleotide that undergoes a cyclic photoreaction upon BL excitation via a signaling state in which the inhibition of the kinase activity by LOV2 is negated. To understand the molecular mechanism underlying the BL-dependent activation of the kinase, the photochemistry, kinase activity, and molecular structure were studied with the phot of Chlamydomonas reinhardtii. Full-length and LOV2-KD samples of C. reinhardtii phot showed cyclic photoreaction characteristics with the activation of LOV- and BL-dependent kinase. Truncation of LOV1 decreased the photosensitivity of the kinase activation, which was well explained by the fact that the signaling state lasted for a shorter period of time compared with that of the phot. Small angle x-ray scattering revealed monomeric forms of the proteins in solution and detected BL-dependent conformational changes, suggesting an extension of the global molecular shapes of both samples. Constructed molecular model of full-length phot based on the small angle x-ray scattering data proved the arrangement of LOV1, LOV2, and KD for the first time that showed a tandem arrangement both in the dark and under BL irradiation. The models suggest that LOV1 alters its position relative to LOV2-KD under BL irradiation. This finding demonstrates that LOV1 may interact with LOV2 and modify the photosensitivity of the kinase activation through alteration of the duration of the signaling state in LOV2.

IRAK2 directs stimulus-dependent nuclear export of inflammatory mRNAs.

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Zhou, Hao; Bulek, Katarzyna; Li, Xiao; Herjan, Tomasz; Yu, Minjia; Qian, Wen; Wang, Han; Zhou, Gao; Chen, Xing; Yang, Hui; Hong, Lingzi; Zhao, Junjie; Qin, Luke; Fukuda, Koichi; Flotho, Annette; Gao, Ji; Dongre, Ashok; Carman, Julie A; Kang, Zizhen; Su, Bing; Kern, Timothy S; Smith, Jonathan D; Hamilton, Thomas A; Melchior, Frauke; Fox, Paul L; Li, Xiaoxia

2017-10-09

Expression of inflammatory genes is determined in part by post-transcriptional regulation of mRNA metabolism but how stimulus- and transcript-dependent nuclear export influence is poorly understood. Here, we report a novel pathway in which LPS/TLR4 engagement promotes nuclear localization of IRAK2 to facilitate nuclear export of a specific subset of inflammation-related mRNAs for translation in murine macrophages. IRAK2 kinase activity is required for LPS-induced RanBP2-mediated IRAK2 sumoylation and subsequent nuclear translocation. Array analysis showed that an SRSF1-binding motif is enriched in mRNAs dependent on IRAK2 for nuclear export. Nuclear IRAK2 phosphorylates SRSF1 to reduce its binding to target mRNAs, which promotes the RNA binding of the nuclear export adaptor ALYREF and nuclear export receptor Nxf1 loading for the export of the mRNAs. In summary, LPS activates a nuclear function of IRAK2 that facilitates the assembly of nuclear export machinery to export selected inflammatory mRNAs to the cytoplasm for translation.

Nuclear EGFRvIII resists hypoxic microenvironment induced apoptosis via recruiting ERK1/2 nuclear translocation

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Xie, Hui; Yang, Jinfeng; Xing, Wenjing; Dong, Yucui [Dept. of Immunology, Harbin Medical University, Harbin 150081 (China); Key Lab Infection & Immunity, Heilongjiang Province, Harbin 150081 (China); Ren, Huan, E-mail: renhuan@ems.hrbmu.edu.cn [Dept. of Immunology, Harbin Medical University, Harbin 150081 (China); Key Lab Infection & Immunity, Heilongjiang Province, Harbin 150081 (China)

2016-02-05

Glioblastoma (GBM) is the most aggressive type of primary brain tumor. Its interaction with the tumor microenvironment promotes tumor progression. Furthermore, GBM bearing expression of EGFRvIII displays more adaptation to tumor microenvironment related stress. But the mechanisms were poorly understood. Here, we presented evidence that in the human U87MG glioblastoma tumor model, EGFRvIII overexpression led aberrant kinase activation and nuclear translocation of EGFRvIII/ERK1/2 under hypoxia, which induced growth advantage by resisting apoptosis. Additionally, EGFRvIII defective in nuclear entry impaired this capacity in hypoxia adaptation, and partially interrupted ERK1/2 nuclear translocation. Pharmacology or genetic interference ERK1/2 decreased hypoxia resistance triggered by EGFRvIII expression, but not EGFRvIII nuclear translocation. In summary, this study identified a novel role for EGFRvIII in hypoxia tolerance, supporting an important link between hypoxia and subcellular localization alterations of the receptor. - Highlights: • Nuclear translocation of EGFRvIII contributes to GBM cell apoptotic resistance by hypoxia. • Nuclear ERK1/2 facilitates EGFRvIII in hypoxia resistance. • EGFRvIII nuclear translocation is not dependent on ERK1/2.

A novel non-canonical mechanism of regulation of MST3 (mammalian Sterile20-related kinase 3).

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Fuller, Stephen J; McGuffin, Liam J; Marshall, Andrew K; Giraldo, Alejandro; Pikkarainen, Sampsa; Clerk, Angela; Sugden, Peter H

2012-03-15

The canonical pathway of regulation of the GCK (germinal centre kinase) III subgroup member, MST3 (mammalian Sterile20-related kinase 3), involves a caspase-mediated cleavage between N-terminal catalytic and C-terminal regulatory domains with possible concurrent autophosphorylation of the activation loop MST3(Thr(178)), induction of serine/threonine protein kinase activity and nuclear localization. We identified an alternative 'non-canonical' pathway of MST3 activation (regulated primarily through dephosphorylation) which may also be applicable to other GCKIII (and GCKVI) subgroup members. In the basal state, inactive MST3 co-immunoprecipitated with the Golgi protein GOLGA2/gm130 (golgin A2/Golgi matrix protein 130). Activation of MST3 by calyculin A (a protein serine/threonine phosphatase 1/2A inhibitor) stimulated (auto)phosphorylation of MST3(Thr(178)) in the catalytic domain with essentially simultaneous cis-autophosphorylation of MST3(Thr(328)) in the regulatory domain, an event also requiring the MST3(341-376) sequence which acts as a putative docking domain. MST3(Thr(178)) phosphorylation increased MST3 kinase activity, but this activity was independent of MST3(Thr(328)) phosphorylation. Interestingly, MST3(Thr(328)) lies immediately C-terminal to a STRAD (Sterile20-related adaptor) pseudokinase-like site identified recently as being involved in binding of GCKIII/GCKVI members to MO25 scaffolding proteins. MST3(Thr(178)/Thr(328)) phosphorylation was concurrent with dissociation of MST3 from GOLGA2/gm130 and association of MST3 with MO25, and MST3(Thr(328)) phosphorylation was necessary for formation of the activated MST3-MO25 holocomplex.

Obesity-Linked Phosphorylation of SIRT1 by Casein Kinase 2 Inhibits Its Nuclear Localization and Promotes Fatty Liver.

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Choi, Sung E; Kwon, Sanghoon; Seok, Sunmi; Xiao, Zhen; Lee, Kwan-Woo; Kang, Yup; Li, Xiaoling; Shinoda, Kosaku; Kajimura, Shingo; Kemper, Byron; Kemper, Jongsook Kim

2017-08-01

Sirtuin1 (SIRT1) deacetylase delays and improves many obesity-related diseases, including nonalcoholic fatty liver disease (NAFLD) and diabetes, and has received great attention as a drug target. SIRT1 function is aberrantly low in obesity, so understanding the underlying mechanisms is important for drug development. Here, we show that obesity-linked phosphorylation of SIRT1 inhibits its function and promotes pathological symptoms of NAFLD. In proteomic analysis, Ser-164 was identified as a major serine phosphorylation site in SIRT1 in obese, but not lean, mice, and this phosphorylation was catalyzed by casein kinase 2 (CK2), the levels of which were dramatically elevated in obesity. Mechanistically, phosphorylation of SIRT1 at Ser-164 substantially inhibited its nuclear localization and modestly affected its deacetylase activity. Adenovirus-mediated liver-specific expression of SIRT1 or a phosphor-defective S164A-SIRT1 mutant promoted fatty acid oxidation and ameliorated liver steatosis and glucose intolerance in diet-induced obese mice, but these beneficial effects were not observed in mice expressing a phosphor-mimic S164D-SIRT1 mutant. Remarkably, phosphorylated S164-SIRT1 and CK2 levels were also highly elevated in liver samples of NAFLD patients and correlated with disease severity. Thus, inhibition of phosphorylation of SIRT1 by CK2 may serve as a new therapeutic approach for treatment of NAFLD and other obesity-related diseases. Copyright © 2017 American Society for Microbiology.

Protein kinases responsible for the phosphorylation of the nuclear egress core complex of human cytomegalovirus.

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Sonntag, Eric; Milbradt, Jens; Svrlanska, Adriana; Strojan, Hanife; Häge, Sigrun; Kraut, Alexandra; Hesse, Anne-Marie; Amin, Bushra; Sonnewald, Uwe; Couté, Yohann; Marschall, Manfred

2017-10-01

Nuclear egress of herpesvirus capsids is mediated by a multi-component nuclear egress complex (NEC) assembled by a heterodimer of two essential viral core egress proteins. In the case of human cytomegalovirus (HCMV), this core NEC is defined by the interaction between the membrane-anchored pUL50 and its nuclear cofactor, pUL53. NEC protein phosphorylation is considered to be an important regulatory step, so this study focused on the respective role of viral and cellular protein kinases. Multiply phosphorylated pUL50 varieties were detected by Western blot and Phos-tag analyses as resulting from both viral and cellular kinase activities. In vitro kinase analyses demonstrated that pUL50 is a substrate of both PKCα and CDK1, while pUL53 can also be moderately phosphorylated by CDK1. The use of kinase inhibitors further illustrated the importance of distinct kinases for core NEC phosphorylation. Importantly, mass spectrometry-based proteomic analyses identified five major and nine minor sites of pUL50 phosphorylation. The functional relevance of core NEC phosphorylation was confirmed by various experimental settings, including kinase knock-down/knock-out and confocal imaging, in which it was found that (i) HCMV core NEC proteins are not phosphorylated solely by viral pUL97, but also by cellular kinases; (ii) both PKC and CDK1 phosphorylation are detectable for pUL50; (iii) no impact of PKC phosphorylation on NEC functionality has been identified so far; (iv) nonetheless, CDK1-specific phosphorylation appears to be required for functional core NEC interaction. In summary, our findings provide the first evidence that the HCMV core NEC is phosphorylated by cellular kinases, and that the complex pattern of NEC phosphorylation has functional relevance.

Human Cytomegalovirus Nuclear Capsids Associate with the Core Nuclear Egress Complex and the Viral Protein Kinase pUL97.

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Milbradt, Jens; Sonntag, Eric; Wagner, Sabrina; Strojan, Hanife; Wangen, Christina; Lenac Rovis, Tihana; Lisnic, Berislav; Jonjic, Stipan; Sticht, Heinrich; Britt, William J; Schlötzer-Schrehardt, Ursula; Marschall, Manfred

2018-01-13

The nuclear phase of herpesvirus replication is regulated through the formation of regulatory multi-component protein complexes. Viral genomic replication is followed by nuclear capsid assembly, DNA encapsidation and nuclear egress. The latter has been studied intensely pointing to the formation of a viral core nuclear egress complex (NEC) that recruits a multimeric assembly of viral and cellular factors for the reorganization of the nuclear envelope. To date, the mechanism of the association of human cytomegalovirus (HCMV) capsids with the NEC, which in turn initiates the specific steps of nuclear capsid budding, remains undefined. Here, we provide electron microscopy-based data demonstrating the association of both nuclear capsids and NEC proteins at nuclear lamina budding sites. Specifically, immunogold labelling of the core NEC constituent pUL53 and NEC-associated viral kinase pUL97 suggested an intranuclear NEC-capsid interaction. Staining patterns with phospho-specific lamin A/C antibodies are compatible with earlier postulates of targeted capsid egress at lamina-depleted areas. Important data were provided by co-immunoprecipitation and in vitro kinase analyses using lysates from HCMV-infected cells, nuclear fractions, or infectious virions. Data strongly suggest that nuclear capsids interact with pUL53 and pUL97. Combined, the findings support a refined concept of HCMV nuclear trafficking and NEC-capsid interaction.

Human Cytomegalovirus Nuclear Capsids Associate with the Core Nuclear Egress Complex and the Viral Protein Kinase pUL97

Directory of Open Access Journals (Sweden)

Jens Milbradt

2018-01-01

Full Text Available The nuclear phase of herpesvirus replication is regulated through the formation of regulatory multi-component protein complexes. Viral genomic replication is followed by nuclear capsid assembly, DNA encapsidation and nuclear egress. The latter has been studied intensely pointing to the formation of a viral core nuclear egress complex (NEC that recruits a multimeric assembly of viral and cellular factors for the reorganization of the nuclear envelope. To date, the mechanism of the association of human cytomegalovirus (HCMV capsids with the NEC, which in turn initiates the specific steps of nuclear capsid budding, remains undefined. Here, we provide electron microscopy-based data demonstrating the association of both nuclear capsids and NEC proteins at nuclear lamina budding sites. Specifically, immunogold labelling of the core NEC constituent pUL53 and NEC-associated viral kinase pUL97 suggested an intranuclear NEC-capsid interaction. Staining patterns with phospho-specific lamin A/C antibodies are compatible with earlier postulates of targeted capsid egress at lamina-depleted areas. Important data were provided by co-immunoprecipitation and in vitro kinase analyses using lysates from HCMV-infected cells, nuclear fractions, or infectious virions. Data strongly suggest that nuclear capsids interact with pUL53 and pUL97. Combined, the findings support a refined concept of HCMV nuclear trafficking and NEC-capsid interaction.

Cocoa Procyanidins Suppress Transformation by Inhibiting Mitogen-activated Protein Kinase Kinase*S⃞

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Kang, Nam Joo; Lee, Ki Won; Lee, Dong Eun; Rogozin, Evgeny A.; Bode, Ann M.; Lee, Hyong Joo; Dong, Zigang

2008-01-01

Cocoa was shown to inhibit chemically induced carcinogenesis in animals and exert antioxidant activity in humans. However, the molecular mechanisms of the chemopreventive potential of cocoa and its active ingredient(s) remain unknown. Here we report that cocoa procyanidins inhibit neoplastic cell transformation by suppressing the kinase activity of mitogen-activated protein kinase kinase (MEK). A cocoa procyanidin fraction (CPF) and procyanidin B2 at 5 μg/ml and 40 μm, respectively, inhibited 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced neoplastic transformation of JB6 P+ mouse epidermal (JB6 P+) cells by 47 and 93%, respectively. The TPA-induced promoter activity and expression of cyclooxygenase-2, which is involved in tumor promotion and inflammation, were dose-dependently inhibited by CPF or procyanidin B2. The activation of activator protein-1 and nuclear factor-κB induced by TPA was also attenuated by CPF or procyanidin B2. The TPA-induced phosphorylation of MEK, extracellular signal-regulated kinase, and p90 ribosomal s6 kinase was suppressed by CPF or procyanidin B2. In vitro and ex vivo kinase assay data demonstrated that CPF or procyanidin B2 inhibited the kinase activity of MEK1 and directly bound with MEK1. CPF or procyanidin B2 suppressed JB6 P+ cell transformation induced by epidermal growth factor or H-Ras, both of which are known to be involved in MEK/ERK signal activation. In contrast, theobromine (up to 80 μm) had no effect on TPA-induced transformation, cyclooxygenase-2 expression, the transactivation of activator protein-1 or nuclear factor-κB, or MEK. Notably, procyanidin B2 exerted stronger inhibitory effects compared with PD098059 (a well known pharmacological inhibitor of MEK) on MEK1 activity and neoplastic cell transformation. PMID:18519570

Role of regulatory subunits and protein kinase inhibitor (PKI) in determining nuclear localization and activity of the catalytic subunit of protein kinase A.

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Wiley, J C; Wailes, L A; Idzerda, R L; McKnight, G S

1999-03-05

Regulation of protein kinase A by subcellular localization may be critical to target catalytic subunits to specific substrates. We employed epitope-tagged catalytic subunit to correlate subcellular localization and gene-inducing activity in the presence of regulatory subunit or protein kinase inhibitor (PKI). Transiently expressed catalytic subunit distributed throughout the cell and induced gene expression. Co-expression of regulatory subunit or PKI blocked gene induction and prevented nuclear accumulation. A mutant PKI lacking the nuclear export signal blocked gene induction but not nuclear accumulation, demonstrating that nuclear export is not essential to inhibit gene induction. When the catalytic subunit was targeted to the nucleus with a nuclear localization signal, it was not sequestered in the cytoplasm by regulatory subunit, although its activity was completely inhibited. PKI redistributed the nuclear catalytic subunit to the cytoplasm and blocked gene induction, demonstrating that the nuclear export signal of PKI can override a strong nuclear localization signal. With increasing PKI, the export process appeared to saturate, resulting in the return of catalytic subunit to the nucleus. These results demonstrate that both the regulatory subunit and PKI are able to completely inhibit the gene-inducing activity of the catalytic subunit even when the catalytic subunit is forced to concentrate in the nuclear compartment.

Nuclear localization of Src-family tyrosine kinases is required for growth factor-induced euchromatinization

International Nuclear Information System (INIS)

Takahashi, Akinori; Obata, Yuuki; Fukumoto, Yasunori; Nakayama, Yuji; Kasahara, Kousuke; Kuga, Takahisa; Higashiyama, Yukihiro; Saito, Takashi; Yokoyama, Kazunari K.; Yamaguchi, Naoto

2009-01-01

Src-family kinases (SFKs), which participate in various signaling events, are found at not only the plasma membrane but also several subcellular compartments, including the nucleus. Nuclear structural changes are frequently observed during transcription, cell differentiation, senescence, tumorigenesis, and cell cycle. However, little is known about signal transduction in the alteration of chromatin texture. Here, we develop a pixel imaging method for quantitatively evaluating chromatin structural changes. Growth factor stimulation increases euchromatic hypocondensation and concomitant heterochromatic hypercondensation in G 1 phase, and the levels reach a plateau by 30 min, sustain for at least 5 h and return to the basal levels after 24 h. Serum-activated SFKs in the nucleus were more frequently detected in the euchromatin areas than the heterochromatin areas. Nuclear expression of kinase-active SFKs, but not unrelated Syk kinase, drastically increases both euchromatinization and heterochromatinization in a manner dependent on the levels of nuclear tyrosine phosphorylation. However, growth factor stimulation does not induce chromatin structural changes in SYF cells lacking SFKs, and reintroduction of one SFK member into SYF cells can, albeit insufficiently, induce chromatin structural changes. These results suggest that nuclear tyrosine phosphorylation by SFKs plays an important role in chromatin structural changes upon growth factor stimulation.

Molecular Mimicry Regulates ABA Signaling by SnRK2 Kinases and PP2C Phosphatases

International Nuclear Information System (INIS)

Soon, Fen-Fen; Ng, Ley-Moy; Zhou, X. Edward; West, Graham M.; Kovach, Amanda; Tan, M.H. Eileen; Suino-Powell, Kelly M.; He, Yuanzheng; Xu, Yong; Chalmers, Michael J.; Brunzelle, Joseph S.; Zhang, Huiming; Yang, Huaiyu; Jiang, Hualiang; Li, Jun; Yong, Eu-Leong; Cutler, Sean; Zhu, Jian-Kang; Griffin, Patrick R.; Melcher, Karsten; Xu, H. Eric

2012-01-01

Abscisic acid (ABA) is an essential hormone for plants to survive environmental stresses. At the center of the ABA signaling network is a subfamily of type 2C protein phosphatases (PP2Cs), which form exclusive interactions with ABA receptors and subfamily 2 Snfl-related kinase (SnRK2s). Here, we report a SnRK2-PP2C complex structure, which reveals marked similarity in PP2C recognition by SnRK2 and ABA receptors. In the complex, the kinase activation loop docks into the active site of PP2C, while the conserved ABA-sensing tryptophan of PP2C inserts into the kinase catalytic cleft, thus mimicking receptor-PP2C interactions. These structural results provide a simple mechanism that directly couples ABA binding to SnRK2 kinase activation and highlight a new paradigm of kinase-phosphatase regulation through mutual packing of their catalytic sites.

Molecular Mimicry Regulates ABA Signaling by SnRK2 Kinases and PP2C Phosphatases

Energy Technology Data Exchange (ETDEWEB)

Soon, Fen-Fen; Ng, Ley-Moy; Zhou, X. Edward; West, Graham M.; Kovach, Amanda; Tan, M.H. Eileen; Suino-Powell, Kelly M.; He, Yuanzheng; Xu, Yong; Chalmers, Michael J.; Brunzelle, Joseph S.; Zhang, Huiming; Yang, Huaiyu; Jiang, Hualiang; Li, Jun; Yong, Eu-Leong; Cutler, Sean; Zhu, Jian-Kang; Griffin, Patrick R.; Melcher, Karsten; Xu, H. Eric (Van Andel); (Scripps); (NWU); (Purdue); (UCR); (Chinese Aca. Sci.); (NU Singapore)

2014-10-02

Abscisic acid (ABA) is an essential hormone for plants to survive environmental stresses. At the center of the ABA signaling network is a subfamily of type 2C protein phosphatases (PP2Cs), which form exclusive interactions with ABA receptors and subfamily 2 Snfl-related kinase (SnRK2s). Here, we report a SnRK2-PP2C complex structure, which reveals marked similarity in PP2C recognition by SnRK2 and ABA receptors. In the complex, the kinase activation loop docks into the active site of PP2C, while the conserved ABA-sensing tryptophan of PP2C inserts into the kinase catalytic cleft, thus mimicking receptor-PP2C interactions. These structural results provide a simple mechanism that directly couples ABA binding to SnRK2 kinase activation and highlight a new paradigm of kinase-phosphatase regulation through mutual packing of their catalytic sites.

SH2 domain-containing phosphatase 1 regulates pyruvate kinase M2 in hepatocellular carcinoma.

Science.gov (United States)

Tai, Wei-Tien; Hung, Man-Hsin; Chu, Pei-Yi; Chen, Yao-Li; Chen, Li-Ju; Tsai, Ming-Hsien; Chen, Min-Husan; Shiau, Chung-Wai; Boo, Yin-Pin; Chen, Kuen-Feng

2016-04-19

Pyruvate kinase M2 (PKM2) is known to promote tumourigenesis through dimer formation of p-PKM2Y105. Here, we investigated whether SH2-containing protein tyrosine phosphatase 1 (SHP-1) decreases p-PKM2Y105 expression and, thus, determines the sensitivity of sorafenib through inhibiting the nuclear-related function of PKM2. Immunoprecipitation and immunoblot confirmed the effect of SHP-1 on PKM2Y105 dephosphorylation. Lactate production was assayed in cells and tumor samples to determine whether sorafenib reversed the Warburg effect. Clinical hepatocellular carcinoma (HCC) tumor samples were assessed for PKM2 expression. SHP-1 directly dephosphorylated PKM2 at Y105 and further decreased the proliferative activity of PKM2; similar effects were found in sorafenib-treated HCC cells. PKM2 was also found to determine the sensitivity of targeted drugs, such as sorafenib, brivanib, and sunitinib, by SHP-1 activation. Significant sphere-forming activity was found in HCC cells stably expressing PKM2. Clinical findings suggest that PKM2 acts as a predicting factor of early recurrence in patients with HCC, particularly those without known risk factors (63.6%). SHP-1 dephosphorylates PKM2 at Y105 to inhibit nuclear function of PKM2 and determines the efficacy of targeted drugs. Targeting PKM2 by SHP-1 might provide new therapeutic insights for patients with HCC.

Glycogen synthase kinase 3 regulates expression of nuclear factor-erythroid-2 related transcription factor-1 (Nrf1) and inhibits pro-survival function of Nrf1

Energy Technology Data Exchange (ETDEWEB)

Biswas, Madhurima; Kwong, Erick K.; Park, Eujean; Nagra, Parminder; Chan, Jefferson Y., E-mail: jchan@uci.edu

2013-08-01

Nuclear factor E2-related factor-1 (Nrf1) is a basic leucine zipper transcription factor that is known to regulate antioxidant and cytoprotective gene expression. It was recently shown that Nrf1 is regulated by SCF–Fbw7 ubiquitin ligase. However our knowledge of upstream signals that targets Nrf1 for degradation by the UPS is not known. We report here that Nrf1 expression is negatively regulated by glycogen synthase kinase 3 (GSK3) in Fbw7-dependent manner. We show that GSK3 interacts with Nrf1 and phosphorylates the Cdc4 phosphodegron domain (CPD) in Nrf1. Mutation of serine residue in the CPD of Nrf1 to alanine (S350A), blocks Nrf1 from phosphorylation by GSK3, and stabilizes Nrf1. Knockdown of Nrf1 and expression of a constitutively active form of GSK3 results in increased apoptosis in neuronal cells in response to ER stress, while expression of the GSK3 phosphorylation resistant S350A–Nrf1 attenuates apoptotic cell death. Together these data suggest that GSK3 regulates Nrf1 expression and cell survival function in response to stress activation. Highlights: • The effect of GSK3 on Nrf1 expression was examined. • GSK3 destabilizes Nrf1 protein via Fbw7 ubiquitin ligase. • GSK3 binds and phosphorylates Nrf1. • Protection from stress-induced apoptosis by Nrf1 is inhibited by GSK3.

Molecular Mimicry Regulates ABA Signaling by SnRK2 Kinases and PP2C Phosphatases

Science.gov (United States)

Soon, Fen-Fen; Ng, Ley-Moy; Zhou, X. Edward; West, Graham M.; Kovach, Amanda; Tan, M. H. Eileen; Suino-Powell, Kelly M.; He, Yuanzheng; Xu, Yong; Chalmers, Michael J.; Brunzelle, Joseph S.; Zhang, Huiming; Yang, Huaiyu; Jiang, Hualiang; Li, Jun; Yong, Eu-Leong; Cutler, Sean; Zhu, Jian-Kang; Griffin, Patrick R.; Melcher, Karsten; Xu, H. Eric

2013-01-01

Abscisic acid (ABA) is an essential hormone for plants to survive environmental stresses. At the center of the ABA signaling network is a subfamily of type 2C protein phosphatases (PP2Cs), which form exclusive interactions with ABA receptors and subfamily 2 Snfl-related kinase (SnRK2s). Here, we report a SnRK2-PP2C complex structure, which reveals marked similarity in PP2C recognition by SnRK2 and ABA receptors. In the complex, the kinase activation loop docks into the active site of PP2C, while the conserved ABA-sensing tryptophan of PP2C inserts into the kinase catalytic cleft, thus mimicking receptor-PP2C interactions. These structural results provide a simple mechanism that directly couples ABA binding to SnRK2 kinase activation and highlight a new paradigm of kinase-phosphatase regulation through mutual packing of their catalytic sites. PMID:22116026

Resorufin: a lead for a new protein kinase CK2 inhibitor

DEFF Research Database (Denmark)

Sandholt, Iben Skjøth; Olsen, Birgitte Brinkmann; Guerra, Barbara

2009-01-01

Screening a natural compound library led to the identification of resorufin as a highly selective and potent inhibitor of protein kinase CK2. Out of 52 kinases tested, only CK2 was inhibited, in contrast to emodin, a structurally related, known CK2 inhibitor that, in addition to CK2, inhibited te...

The Link between Protein Kinase CK2 and Atypical Kinase Rio1

Directory of Open Access Journals (Sweden)

Konrad Kubiński

2017-02-01

Full Text Available The atypical kinase Rio1 is widespread in many organisms, ranging from Archaebacteria to humans, and is an essential factor in ribosome biogenesis. Little is known about the protein substrates of the enzyme and small-molecule inhibitors of the kinase. Protein kinase CK2 was the first interaction partner of Rio1, identified in yeast cells. The enzyme from various sources undergoes CK2-mediated phosphorylation at several sites and this modification regulates the activity of Rio1. The aim of this review is to present studies of the relationship between the two different kinases, with respect to CK2-mediated phosphorylation of Rio1, regulation of Rio1 activity, and similar susceptibility of the kinases to benzimidazole inhibitors.

Sulforaphane Inhibits Lipopolysaccharide-Induced Inflammation, Cytotoxicity, Oxidative Stress, and miR-155 Expression and Switches to Mox Phenotype through Activating Extracellular Signal-Regulated Kinase 1/2-Nuclear Factor Erythroid 2-Related Factor 2/Antioxidant Response Element Pathway in Murine Microglial Cells.

Science.gov (United States)

Eren, Erden; Tufekci, Kemal Ugur; Isci, Kamer Burak; Tastan, Bora; Genc, Kursad; Genc, Sermin

2018-01-01

Sulforaphane (SFN) is a natural product with cytoprotective, anti-inflammatory, and antioxidant effects. In this study, we evaluated the mechanisms of its effects on lipopolysaccharide (LPS)-induced cell death, inflammation, oxidative stress, and polarization in murine microglia. We found that SFN protects N9 microglial cells upon LPS-induced cell death and suppresses LPS-induced levels of secreted pro-inflammatory cytokines, tumor necrosis factor-alpha, interleukin-1 beta, and interleukin-6. SFN is also a potent inducer of redox sensitive transcription factor, nuclear factor erythroid 2-related factor 2 (Nrf2), which is responsible for the transcription of antioxidant, cytoprotective, and anti-inflammatory genes. SFN induced translocation of Nrf2 to the nucleus via extracellular signal-regulated kinase 1/2 (ERK1/2) pathway activation. siRNA-mediated knockdown study showed that the effects of SFN on LPS-induced reactive oxygen species, reactive nitrogen species, and pro-inflammatory cytokine production and cell death are partly Nrf2 dependent. Mox phenotype is a novel microglial phenotype that has roles in oxidative stress responses. Our results suggested that SFN induced the Mox phenotype in murine microglia through Nrf2 pathway. SFN also alleviated LPS-induced expression of inflammatory microRNA, miR-155. Finally, SFN inhibits microglia-mediated neurotoxicity as demonstrated by conditioned medium and co-culture experiments. In conclusion, SFN exerts protective effects on microglia and modulates the microglial activation state.

Cell-cycle-specific interaction of nuclear DNA-binding proteins with a CCAAT sequence from the human thymidine kinase gene

International Nuclear Information System (INIS)

Knight, G.B.; Gudas, J.M.; Pardee, A.B.

1987-01-01

Induction of thymidine kinase parallels the onset of DNA synthesis. To investigate the transcriptional regulation of the thymidine kinase gene, the authors have examined whether specific nuclear factors interact in a cell-cycle-dependent manner with sequences upstream of this gene. Two inverted CCAAT boxes near the transcriptional initiation sites were observed to form complexes with nuclear DNA-binding proteins. The nature of the complexes changes dramatically as the cells approach DNA synthesis and correlates well with the previously reported transcriptional increase of the thymidine kinase gene

Structural coupling of SH2-kinase domains links Fes and Abl substrate recognition and kinase activation.

Science.gov (United States)

Filippakopoulos, Panagis; Kofler, Michael; Hantschel, Oliver; Gish, Gerald D; Grebien, Florian; Salah, Eidarus; Neudecker, Philipp; Kay, Lewis E; Turk, Benjamin E; Superti-Furga, Giulio; Pawson, Tony; Knapp, Stefan

2008-09-05

The SH2 domain of cytoplasmic tyrosine kinases can enhance catalytic activity and substrate recognition, but the molecular mechanisms by which this is achieved are poorly understood. We have solved the structure of the prototypic SH2-kinase unit of the human Fes tyrosine kinase, which appears specialized for positive signaling. In its active conformation, the SH2 domain tightly interacts with the kinase N-terminal lobe and positions the kinase alphaC helix in an active configuration through essential packing and electrostatic interactions. This interaction is stabilized by ligand binding to the SH2 domain. Our data indicate that Fes kinase activation is closely coupled to substrate recognition through cooperative SH2-kinase-substrate interactions. Similarly, we find that the SH2 domain of the active Abl kinase stimulates catalytic activity and substrate phosphorylation through a distinct SH2-kinase interface. Thus, the SH2 and catalytic domains of active Fes and Abl pro-oncogenic kinases form integrated structures essential for effective tyrosine kinase signaling.

2,2',4,4'-Tetrachlorobiphenyl upregulates cyclooxygenase-2 in HL-60 cells via p38 mitogen-activated protein kinase and NF-κB

International Nuclear Information System (INIS)

Bezdecny, Steven A.; Karmaus, Peer; Roth, Robert A.; Ganey, Patricia E.

2007-01-01

Polychlorinated biphenyls (PCBs) are ubiquitous, persistent environmental contaminants that affect a number of cellular systems, including neutrophils. Among the effects caused by the noncoplanar PCB 2,2',4,4'-tetrachlorobiphenyl (2244-TCB) in granulocytic HL-60 cells are increases in superoxide anion production, activation of phospholipase A 2 with subsequent release of arachidonic acid (AA) and upregulation of the inflammatory gene cyclooxygenase-2 (COX-2). The objective of this study was to determine the signal transduction pathways involved in the upregulation of COX-2 by 2244-TCB. Treatment of HL-60 cells with 2244-TCB led to increased expression of COX-2 mRNA. This increase was prevented by the transcriptional inhibitor actinomycin D in cells pretreated with 2244-TCB for 10 min. The increase in COX-2 mRNA was associated with release of 3 H-AA, phosphorylation of p38 and extracellular signal-regulated kinase (ERK) mitogen-activated protein (MAP) kinases, increased levels of nuclear NF-κB and increased superoxide anion production. Bromoenol lactone, an inhibitor of the calcium-independent phospholipase A 2 , reduced 3 H-AA release but had no effect on COX-2 mRNA, protein or activity. Pretreatment with SB-202190 or SB-203580, inhibitors of the p38 MAP kinase pathway, prevented the 2244-TCB-mediated induction of COX-2 and phosphorylation of p38 and ERK MAP kinases. These inhibitors did not alter 3 H-AA release. Treatment with PD 98059 or U 0126, inhibitors of the MAP/ERK (MEK) pathway, prevented the 2244-TCB-mediated activation of ERK but had no effect on COX-2 induction or p38 phosphorylation. 2244-TCB treatment did not affect c-Jun N-terminal kinase (JNK) phosphorylation. 2244-TCB exposure increased the amount of nuclear NF-κB. This increase was prevented by pretreatment with p38 MAP kinase inhibitors, but not by pretreatment with MEK inhibitors. Pretreatment with inhibitors of NF-κB prevented the 2244-TCB-mediated induction of COX-2 mRNA. 2244-TCB

Protein kinase CK2 in health and disease: Protein kinase CK2: from structures to insights

DEFF Research Database (Denmark)

Niefind, K; Raaf, J; Issinger, Olaf-Georg

2009-01-01

the critical region of CK2alpha recruitment is pre-formed in the unbound state. In CK2alpha the activation segment - a key element of protein kinase regulation - adapts invariably the typical conformation of the active enzymes. Recent structures of human CK2alpha revealed a surprising plasticity in the ATP......Within the last decade, 40 crystal structures corresponding to protein kinase CK2 (former name 'casein kinase 2'), to its catalytic subunit CK2alpha and to its regulatory subunit CK2beta were published. Together they provide a valuable, yet by far not complete basis to rationalize the biochemical...

Characterization, subcellular localization and nuclear targeting of casein kinase 2 from Zea mays

DEFF Research Database (Denmark)

Peracchia, G; Jensen, A B; Culiáñez-Macià, F A

1999-01-01

We have isolated and characterized the genomic clone of maize casein kinase 2 (CK2) alpha subunit using the previously described alphaCK2-1 cDNA clone as a probe. The genomic clone is 7.5 kb long and contains 10 exons, separated by 9 introns of different size, two larger than 1.5 kb and the others...

Marine-Derived 2-Aminoimidazolone Alkaloids. Leucettamine B-Related Polyandrocarpamines Inhibit Mammalian and Protozoan DYRK & CLK Kinases

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Nadège Loaëc

2017-10-01

Full Text Available A large diversity of 2-aminoimidazolone alkaloids is produced by various marine invertebrates, especially by the marine Calcareous sponges Leucetta and Clathrina. The phylogeny of these sponges and the wide scope of 2-aminoimidazolone alkaloids they produce are reviewed in this article. The origin (invertebrate cells, associated microorganisms, or filtered plankton, physiological functions, and natural molecular targets of these alkaloids are largely unknown. Following the identification of leucettamine B as an inhibitor of selected protein kinases, we synthesized a family of analogues, collectively named leucettines, as potent inhibitors of DYRKs (dual-specificity, tyrosine phosphorylation regulated kinases and CLKs (cdc2-like kinases and potential pharmacological leads for the treatment of several diseases, including Alzheimer’s disease and Down syndrome. We assembled a small library of marine sponge- and ascidian-derived 2-aminoimidazolone alkaloids, along with several synthetic analogues, and tested them on a panel of mammalian and protozoan kinases. Polyandrocarpamines A and B were found to be potent and selective inhibitors of DYRKs and CLKs. They inhibited cyclin D1 phosphorylation on a DYRK1A phosphosite in cultured cells. 2-Aminoimidazolones thus represent a promising chemical scaffold for the design of potential therapeutic drug candidates acting as specific inhibitors of disease-relevant kinases, and possibly other disease-relevant targets.

Pyruvate kinase M2: a potential target for regulating inflammation

Directory of Open Access Journals (Sweden)

Jose Carlos eAlves-Filho

2016-04-01

Full Text Available Pyruvate kinase (PK is the enzyme responsible for catalyzing the last step of glycolysis. Of the four PK isoforms expressed in mammalian cells, PKM2 has generated the most interest due to its impact on changes in cellular metabolism observed in cancer as well as in activated immune cells. As our understanding of dysregulated metabolism in cancer develops, and in light of the growing field of immunometabolism, intense efforts are in place to define the mechanism by which PKM2 regulates the metabolic profile of cancer as well as of immune cells. The enzymatic activity of PKM2 is heavily regulated by endogenous allosteric effectors as well as by intracellular signalling pathways, affecting both the enzymatic activity of PKM2 as a pyruvate kinase and the regulation of the recently described non-canonical nuclear functions of PKM2. We here review the current literature on PKM2 and its regulation, and discuss the potential for PKM2 as a therapeutic target in inflammatory and metabolic disorders.

ISINN-2. Neutron spectroscopy, nuclear structure and related topics

International Nuclear Information System (INIS)

1994-01-01

The proceedings contain the materials presented at the Second International Seminar on Neutron-Nucleus Interactions (ISINN-2) dealing with the problems of neutron spectroscopy, nuclear structure and related topics. The Seminar took place in Dubna on April 26-28, 1994. Over 120 scientists from Belgium, Bulgaria, Czech Republic, Germany, Holland, Italy, Japan, Latvia, Mexico, Poland, Slovakia, Slovenia, Ukraine, US and about 10 Russian research institutes took part in the Seminar. The main problems discussed are the following: P-odd and P-even angular correlation and T-reversal invariance in neutron reactions, nuclear structure investigations by neutron capture, the mechanism of neutron reactions, nuclear fission processes, as well as neutron data for nuclear astrophysics

Allosteric Inhibition of Bcr-Abl Kinase by High Affinity Monobody Inhibitors Directed to the Src Homology 2 (SH2)-Kinase Interface*

Science.gov (United States)

Wojcik, John; Lamontanara, Allan Joaquim; Grabe, Grzegorz; Koide, Akiko; Akin, Louesa; Gerig, Barbara; Hantschel, Oliver; Koide, Shohei

2016-01-01

Bcr-Abl is a constitutively active kinase that causes chronic myelogenous leukemia. We have shown that a tandem fusion of two designed binding proteins, termed monobodies, directed to the interaction interface between the Src homology 2 (SH2) and kinase domains and to the phosphotyrosine-binding site of the SH2 domain, respectively, inhibits the Bcr-Abl kinase activity. Because the latter monobody inhibits processive phosphorylation by Bcr-Abl and the SH2-kinase interface is occluded in the active kinase, it remained undetermined whether targeting the SH2-kinase interface alone was sufficient for Bcr-Abl inhibition. To address this question, we generated new, higher affinity monobodies with single nanomolar KD values targeting the kinase-binding surface of SH2. Structural and mutagenesis studies revealed the molecular underpinnings of the monobody-SH2 interactions. Importantly, the new monobodies inhibited Bcr-Abl kinase activity in vitro and in cells, and they potently induced cell death in chronic myelogenous leukemia cell lines. This work provides strong evidence for the SH2-kinase interface as a pharmacologically tractable site for allosteric inhibition of Bcr-Abl. PMID:26912659

Allosteric Inhibition of Bcr-Abl Kinase by High Affinity Monobody Inhibitors Directed to the Src Homology 2 (SH2)-Kinase Interface.

Science.gov (United States)

Wojcik, John; Lamontanara, Allan Joaquim; Grabe, Grzegorz; Koide, Akiko; Akin, Louesa; Gerig, Barbara; Hantschel, Oliver; Koide, Shohei

2016-04-15

Bcr-Abl is a constitutively active kinase that causes chronic myelogenous leukemia. We have shown that a tandem fusion of two designed binding proteins, termed monobodies, directed to the interaction interface between the Src homology 2 (SH2) and kinase domains and to the phosphotyrosine-binding site of the SH2 domain, respectively, inhibits the Bcr-Abl kinase activity. Because the latter monobody inhibits processive phosphorylation by Bcr-Abl and the SH2-kinase interface is occluded in the active kinase, it remained undetermined whether targeting the SH2-kinase interface alone was sufficient for Bcr-Abl inhibition. To address this question, we generated new, higher affinity monobodies with single nanomolar KD values targeting the kinase-binding surface of SH2. Structural and mutagenesis studies revealed the molecular underpinnings of the monobody-SH2 interactions. Importantly, the new monobodies inhibited Bcr-Abl kinase activity in vitro and in cells, and they potently induced cell death in chronic myelogenous leukemia cell lines. This work provides strong evidence for the SH2-kinase interface as a pharmacologically tractable site for allosteric inhibition of Bcr-Abl. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Loss of thymidine kinase 2 alters neuronal bioenergetics and leads to neurodegeneration

OpenAIRE

Bartesaghi, Stefano; Betts-Henderson, Joanne; Cain, Kelvin; Dinsdale, David; Zhou, Xiaoshan; Karlsson, Anna; Salomoni, Paolo; Nicotera, Pierluigi

2010-01-01

Mutations of thymidine kinase 2 (TK2), an essential component of the mitochondrial nucleotide salvage pathway, can give rise to mitochondrial DNA (mtDNA) depletion syndromes (MDS). These clinically heterogeneous disorders are characterized by severe reduction in mtDNA copy number in affected tissues and are associated with progressive myopathy, hepatopathy and/or encephalopathy, depending in part on the underlying nuclear genetic defect. Mutations of TK2 have previously been associated with a...

Vital role of protein kinase C-related kinase (PRK1) in the formation and stability of neurites during hypoxia

OpenAIRE

Thauerer, Bettina; zur Nedden, Stephanie; Baier-Bitterlich, Gabriele

2010-01-01

Exposure of pheochromocytoma (PC12) cells to hypoxia (1% O2) favors differentiation at the expense of cell viability. Additional incubation with nerve growth factor (NGF) and guanosine, a purine nucleoside with neurotrophin characteristics, rescued cell viability and further enhanced the extension of neurites. In parallel, an increase in the activity of protein kinase C-related kinase (PRK1), which is known to be involved in regulation of the actin cytoskeleton, was observed in hypoxic cells....

SOS2-LIKE PROTEIN KINASE5, an SNF1-RELATED PROTEIN KINASE3-Type Protein Kinase, Is Important for Abscisic Acid Responses in Arabidopsis through Phosphorylation of ABSCISIC ACID-INSENSITIVE51[OPEN

Science.gov (United States)

Zhou, Xiaona; Hao, Hongmei; Zhang, Yuguo; Bai, Yili; Zhu, Wenbo; Qin, Yunxia; Yuan, Feifei; Zhao, Feiyi; Wang, Mengyao; Hu, Jingjiang; Xu, Hong; Guo, Aiguang; Zhao, Huixian; Zhao, Yang; Cao, Cuiling; Yang, Yongqing; Schumaker, Karen S.; Guo, Yan; Xie, Chang Gen

2015-01-01

Abscisic acid (ABA) plays an essential role in seed germination. In this study, we demonstrate that one SNF1-RELATED PROTEIN KINASE3-type protein kinase, SOS2-LIKE PROTEIN KINASE5 (PKS5), is involved in ABA signal transduction via the phosphorylation of an interacting protein, ABSCISIC ACID-INSENSITIVE5 (ABI5). We found that pks5-3 and pks5-4, two previously identified PKS5 superactive kinase mutants with point mutations in the PKS5 FISL/NAF (a conserved peptide that is necessary for interaction with SOS3 or SOS3-LIKE CALCIUM BINDING PROTEINs) motif and the kinase domain, respectively, are hypersensitive to ABA during seed germination. PKS5 was found to interact with ABI5 in yeast (Saccharomyces cerevisiae), and this interaction was further confirmed in planta using bimolecular fluorescence complementation. Genetic studies revealed that ABI5 is epistatic to PKS5. PKS5 phosphorylates a serine (Ser) residue at position 42 in ABI5 and regulates ABA-responsive gene expression. This phosphorylation was induced by ABA in vivo and transactivated ABI5. Expression of ABI5, in which Ser-42 was mutated to alanine, could not fully rescue the ABA-insensitive phenotypes of the abi5-8 and pks5-4abi5-8 mutants. In contrast, mutating Ser-42 to aspartate rescued the ABA insensitivity of these mutants. These data demonstrate that PKS5-mediated phosphorylation of ABI5 at Ser-42 is critical for the ABA regulation of seed germination and gene expression in Arabidopsis (Arabidopsis thaliana). PMID:25858916

n-Butyrate inhibits Jun NH(2)-terminal kinase activation and cytokine transcription in mast cells

International Nuclear Information System (INIS)

Diakos, Christos; Prieschl, Eva E.; Saeemann, Marcus D.; Boehmig, Georg A.; Csonga, Robert; Sobanov, Yury; Baumruker, Thomas; Zlabinger, Gerhard J.

2006-01-01

Mast cells are well known to contribute to type I allergic conditions but only recently have been brought in association with chronic relapsing/remitting autoimmune diseases such as celiac disease and ulcerative colitis. Since the bacterial metabolite n-butyrate is considered to counteract intestinal inflammation we investigated the effects of this short chain fatty acid on mast cell activation. Using RNAse protection assays and reporter gene technology we show that n-butyrate downregulates TNF-α transcription. This correlates with an impaired activation of the Jun NH(2)-terminal kinase (JNK) but not other MAP kinases such as ERK and p38 that are largely unaffected by n-butyrate. As a consequence, we observed a decreased nuclear activity of AP-1 and NF-AT transcription factors. These results indicate that n-butyrate inhibits critical inflammatory mediators in mast cells by relatively selectively targeting the JNK signalling

Expression of Plant Receptor Kinases in Tobacco BY-2 Cells.

Science.gov (United States)

Shinohara, Hidefumi; Matsubayashi, Yoshikatsu

2017-01-01

Although more than 600 single-transmembrane receptor kinase genes have been found in the Arabidopsis genome, only a few of them have known physiological functions, and even fewer plant receptor kinases have known specific ligands. Ligand-binding analysis must be operated using the functionally expressed receptor form. However, the relative abundance of native receptor kinase molecules in the plasma membrane is often quite low. Here, we present a method for stable and functional expression of plant receptor kinases in tobacco BY-2 cells that allows preparation of microsomal fractions containing the receptor. This procedure provides a sufficient amount of receptor proteins while maintaining its ligand-binding activities.

The SH2 domain of Abl kinases regulates kinase autophosphorylation by controlling activation loop accessibility

Science.gov (United States)

Lamontanara, Allan Joaquim; Georgeon, Sandrine; Tria, Giancarlo; Svergun, Dmitri I.; Hantschel, Oliver

2014-11-01

The activity of protein kinases is regulated by multiple molecular mechanisms, and their disruption is a common driver of oncogenesis. A central and almost universal control element of protein kinase activity is the activation loop that utilizes both conformation and phosphorylation status to determine substrate access. In this study, we use recombinant Abl tyrosine kinases and conformation-specific kinase inhibitors to quantitatively analyse structural changes that occur after Abl activation. Allosteric SH2-kinase domain interactions were previously shown to be essential for the leukemogenesis caused by the Bcr-Abl oncoprotein. We find that these allosteric interactions switch the Abl activation loop from a closed to a fully open conformation. This enables the trans-autophosphorylation of the activation loop and requires prior phosphorylation of the SH2-kinase linker. Disruption of the SH2-kinase interaction abolishes activation loop phosphorylation. Our analysis provides a molecular mechanism for the SH2 domain-dependent activation of Abl that may also regulate other tyrosine kinases.

Protein kinase CK2 in human diseases

DEFF Research Database (Denmark)

Guerra, Barbara; Issinger, Olaf-Georg

2008-01-01

Protein kinase CK2 (formerly referred to as casein kinase II) is an evolutionary conserved, ubiquitous protein kinase. There are two paralog catalytic subunits, i.e. alpha (A1) and alpha' (A2). The alpha and alpha' subunits are linked to two beta subunits to produce a heterotetrameric structure...

DMPD: Manipulation of mitogen-activated protein kinase/nuclear factor-kappaB-signalingcascades during intracellular Toxoplasma gondii infection. [Dynamic Macrophage Pathway CSML Database

Lifescience Database Archive (English)

Full Text Available 15361242 Manipulation of mitogen-activated protein kinase/nuclear factor-kappaB-sig...mmunol Rev. 2004 Oct;201:191-205. (.png) (.svg) (.html) (.csml) Show Manipulation of mitogen-activated prote... gondii infection. PubmedID 15361242 Title Manipulation of mitogen-activated protein kinase/nuclear factor-k

Phosphorylation of the Epstein-Barr virus nuclear antigen 2

DEFF Research Database (Denmark)

Grässer, F A; Göttel, S; Haiss, P

1992-01-01

A major in vivo phosphorylation site of the Epstein-Barr virus nuclear antigen 2 (EBNA-2) was found to be localized at the C-terminus of the protein. In vitro phosphorylation studies using casein kinase 1 (CK-1) and casein kinase 2 (CK-2) revealed that EBNA-2 is a substrate for CK-2, but not for CK......-1. The CK-2 specific phosphorylation site was localized in the 140 C-terminal amino acids using a recombinant trpE-C-terminal fusion protein. In a similar experiment, the 58 N-terminal amino acids expressed as a recombinant trpE-fusion protein were not phosphorylated. Phosphorylation of a synthetic...

Inhibitory effects of homeodomain-interacting protein kinase 2 on the aorta-gonad-mapharsen hematopoiesis

International Nuclear Information System (INIS)

Ohtsu, Naoki; Nobuhisa, Ikuo; Mochita, Miyuki; Taga, Tetsuya

2007-01-01

Definitive hematopoiesis starts in the aorta-gonad-mesonephros (AGM) region of the mouse embryo. Our previous studies revealed that STAT3, a gp130 downstream transcription factor, is required for AGM hematopoiesis and that homeodomain-interacting protein kinase 2 (HIPK2) phosphorylates serine-727 of STAT3. HIPK2 is a serine/threonine kinase known to be involved in transcriptional repression and apoptosis. In the present study, we examined the role of HIPK2 in hematopoiesis in mouse embryo. HIPK2 transcripts were found in fetal hematopoietic tissues such as the mouse AGM region and fetal liver. In cultured AGM cells, HIPK2 protein was detected in adherent cells. Functional analyses of HIPK2 were carried out by introducing wild-type and mutant HIPK2 constructs into AGM cultures. Production of CD45 + hematopoietic cells was suppressed by forced expression of HIPK2 in AGM cultures. This suppression required the kinase domain and nuclear localization signals of HIPK2, but the kinase activity was dispensable. HIPK2-overexpressing AGM-derived nonadherent cells did not form cobblestone-like colonies in cultures with stromal cells. Furthermore, overexpression of HIPK2 in AGM cultures impeded the expansion of CD45 low c-Kit + cells, which exhibit the immature hematopoietic progenitor phenotype. These data indicate that HIPK2 plays a negative regulatory role in AGM hematopoiesis in the mouse embryo

Nuclear factor erythroid 2-related factor 2 deletion impairs glucose tolerance and exacerbates hyperglycemia in type 1 diabetic mice.

Science.gov (United States)

Aleksunes, Lauren M; Reisman, Scott A; Yeager, Ronnie L; Goedken, Michael J; Klaassen, Curtis D

2010-04-01

The transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) induces a battery of cytoprotective genes after oxidative stress. Nrf2 aids in liver regeneration by altering insulin signaling; however, whether Nrf2 participates in hepatic glucose homeostasis is unknown. Compared with wild-type mice, mice lacking Nrf2 (Nrf2-null) have lower basal serum insulin and prolonged hyperglycemia in response to an intraperitoneal glucose challenge. In the present study, blood glucose, serum insulin, urine flow rate, and hepatic expression of glucose-related genes were quantified in male diabetic wild-type and Nrf2-null mice. Type 1 diabetes was induced with a single intraperitoneal dose (200 mg/kg) of streptozotocin (STZ). Histopathology and serum insulin levels confirmed depleted pancreatic beta-cells in STZ-treated mice of both genotypes. Five days after STZ, Nrf2-null mice had higher blood glucose levels than wild-type mice. Nine days after STZ, polyuria occurred in both genotypes with more urine output from Nrf2-null mice (11-fold) than wild-type mice (7-fold). Moreover, STZ-treated Nrf2-null mice had higher levels of serum beta-hydroxybutyrate, triglycerides, and fatty acids 10 days after STZ compared with wild-type mice. STZ reduced hepatic glycogen in both genotypes, with less observed in Nrf2-null mice. Increased urine output and blood glucose in STZ-treated Nrf2-null mice corresponded with enhanced gluconeogenesis (glucose-6-phosphatase and phosphoenolpyruvate carboxykinase)- and reduced glycolysis (pyruvate kinase)-related mRNA expression in their livers. Furthermore, the Nrf2 activator oltipraz lowered blood glucose in wild-type but not Nrf2-null mice administered STZ. Collectively, these data indicate that the absence of Nrf2 worsens hyperglycemia in type I diabetic mice and Nrf2 may represent a therapeutic target for reducing circulating glucose levels.

c-Jun NH2-terminal kinase activity in subcutaneous adipose tissue but not nuclear factor-kappaB activity in peripheral blood mononuclear cells is an independent determinant of insulin resistance in healthy individuals

DEFF Research Database (Denmark)

Sourris, Karly C; Lyons, Jasmine G; de Courten, Maximilian

2009-01-01

Chronic low-grade activation of the immune system (CLAIS) predicts type 2 diabetes via a decrease in insulin sensitivity. Our study investigated potential relationships between nuclear factor-kappaB (NF-kappaB) and c-Jun NH(2)-terminal kinase (JNK) pathways-two pathways proposed as the link between...

SH2 domains: modulators of nonreceptor tyrosine kinase activity.

Science.gov (United States)

Filippakopoulos, Panagis; Müller, Susanne; Knapp, Stefan

2009-12-01

The Src homology 2 (SH2) domain is a sequence-specific phosphotyrosine-binding module present in many signaling molecules. In cytoplasmic tyrosine kinases, the SH2 domain is located N-terminally to the catalytic kinase domain (SH1) where it mediates cellular localization, substrate recruitment, and regulation of kinase activity. Initially, structural studies established a role of the SH2 domain stabilizing the inactive state of Src family members. However, biochemical characterization showed that the presence of the SH2 domain is frequently required for catalytic activity, suggesting a crucial function stabilizing the active state of many nonreceptor tyrosine kinases. Recently, the structure of the SH2-kinase domain of Fes revealed that the SH2 domain stabilizes the active kinase conformation by direct interactions with the regulatory helix alphaC. Stabilizing interactions between the SH2 and the kinase domains have also been observed in the structures of active Csk and Abl. Interestingly, mutations in the SH2 domain found in human disease can be explained by SH2 domain destabilization or incorrect positioning of the SH2. Here we summarize our understanding of mechanisms that lead to tyrosine kinase activation by direct interactions mediated by the SH2 domain and discuss how mutations in the SH2 domain trigger kinase inactivation.

Molecular Mimicry Regulates ABA Signaling by SnRK2 Kinases and PP2C Phosphatases

OpenAIRE

Soon, Fen-Fen; Ng, Ley-Moy; Zhou, X. Edward; West, Graham M.; Kovach, Amanda; Tan, M. H. Eileen; Suino-Powell, Kelly M.; He, Yuanzheng; Xu, Yong; Chalmers, Michael J.; Brunzelle, Joseph S.; Zhang, Huiming; Yang, Huaiyu; Jiang, Hualiang; Li, Jun

2011-01-01

Abscisic acid (ABA) is an essential hormone for plants to survive environmental stresses. At the center of the ABA signaling network is a subfamily of type 2C protein phosphatases (PP2Cs), which form exclusive interactions with ABA receptors and subfamily 2 Snfl-related kinase (SnRK2s). Here, we report a SnRK2-PP2C complex structure, which reveals marked similarity in PP2C recognition by SnRK2 and ABA receptors. In the complex, the kinase activation loop docks into the active site of PP2C, wh...

Partial purification and characterization of a Ca(2+)-dependent protein kinase from pea nuclei

Science.gov (United States)

Li, H.; Dauwalder, M.; Roux, S. J.

1991-01-01

Almost all the Ca(2+)-dependent protein kinase activity in nuclei purified from etiolated pea (Pisum sativum, L.) plumules is present in a single enzyme that can be extracted from chromatin by 0.3 molar NaCl. This protein kinase can be further purified 80,000-fold by salt fractionation and high performance liquid chromatography, after which it has a high specific activity of about 100 picomoles per minute per microgram in the presence of Ca2+ and reaches half-maximal activation at about 3 x 10(-7) molar free Ca2+, without calmodulin. It is a monomer with a molecular weight near 90,000. It can efficiently use histone III-S, ribosomal S6 protein, and casein as artificial substrates, but it phosphorylates phosvitin only weakly. Its Ca(2+)-dependent kinase activity is half-maximally inhibited by 0.1 millimolar chlorpromazine, by 35 nanomolar K-252a and by 7 nanomolar staurosporine. It is insensitive to sphingosine, an inhibitor of protein kinase C, and to basic polypeptides that block other Ca(2+)-dependent protein kinases. It is not stimulated by exogenous phospholipids or fatty acids. In intact isolated pea nuclei it preferentially phosphorylates several chromatin-associated proteins, with the most phosphorylated protein band being near the same molecular weight (43,000) as a nuclear protein substrate whose phosphorylation has been reported to be stimulated by phytochrome in a calcium-dependent fashion.

The protein kinase MBK-1 contributes to lifespan extension in daf-2 mutant and germline-deficient Caenorhabditis elegans.

Science.gov (United States)

Mack, Hildegard I D; Zhang, Peichuan; Fonslow, Bryan R; Yates, John R

2017-05-25

In Caenorhabditis elegans , reduction of insulin/IGF-1 like signaling and loss of germline stem cells both increase lifespan by activating the conserved transcription factor DAF-16 (FOXO). While the mechanisms that regulate DAF-16 nuclear localization in response to insulin/IGF-1 like signaling are well characterized, the molecular pathways that act in parallel to regulate DAF-16 transcriptional activity, and the pathways that couple DAF-16 activity to germline status, are not fully understood at present. Here, we report that inactivation of MBK-1, the C. elegans ortholog of the human FOXO1-kinase DYRK1A substantially shortens the prolonged lifespan of daf-2 and glp-1 mutant animals while decreasing wild-type lifespan to a lesser extent. On the other hand, lifespan-reduction by mutation of the MBK-1-related kinase HPK-1 was not preferential for long-lived mutants. Interestingly, mbk-1 loss still allowed for DAF-16 nuclear accumulation but reduced expression of certain DAF-16 target genes in germline-less, but not in daf-2 mutant animals. These findings indicate that mbk-1 and daf-16 functionally interact in the germline- but not in the daf-2 pathway. Together, our data suggest mbk-1 as a novel regulator of C. elegans longevity upon both, germline ablation and DAF-2 inhibition, and provide evidence for mbk-1 regulating DAF-16 activity in germline-deficient animals.

Phosphorylation of nm23/nucleoside diphosphate kinase by casein kinase 2 in vitro

DEFF Research Database (Denmark)

Engel, M; Issinger, O G; Lascu, I

1994-01-01

We have investigated phosphorylation of human nucleoside diphosphate kinase (NDPK) and of homologous NDPK from different species by human casein kinase 2 (CK-2). The human NDPK isotypes A and B were phosphorylated by CK-2 in vitro both when the purified proteins and total lysate of HL-60 leukemia...

Small Molecules Targeting Ataxia Telangiectasia and Rad3-Related (ATR) Kinase: An Emerging way to Enhance Existing Cancer Therapy

Czech Academy of Sciences Publication Activity Database

Andrs, M.; Korábečný, J.; Nepovimova, E.; Jun, D.; Hodný, Zdeněk; Kuca, K.

2016-01-01

Roč. 16, č. 3 (2016), s. 200-208 ISSN 1568-0096 Institutional support: RVO:68378050 Keywords : Ataxia telangiectasia and Rad3-related kinase (ATR) * cancer * chemosensitization * DNA damage response * phosphatidylinositol 3-kinase-related protein kinases (PIKK) * radiosensitization * synthetic lethality Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.992, year: 2016

Catalase overexpression prevents nuclear factor erythroid 2-related factor 2 stimulation of renal angiotensinogen gene expression, hypertension, and kidney injury in diabetic mice.

Science.gov (United States)

Abdo, Shaaban; Shi, Yixuan; Otoukesh, Abouzar; Ghosh, Anindya; Lo, Chao-Sheng; Chenier, Isabelle; Filep, Janos G; Ingelfinger, Julie R; Zhang, Shao Ling; Chan, John S D

2014-10-01

This study investigated the impact of catalase (Cat) overexpression in renal proximal tubule cells (RPTCs) on nuclear factor erythroid 2-related factor 2 (Nrf2) stimulation of angiotensinogen (Agt) gene expression and the development of hypertension and renal injury in diabetic Akita transgenic mice. Additionally, adult male mice were treated with the Nrf2 activator oltipraz with or without the inhibitor trigonelline. Rat RPTCs, stably transfected with plasmid containing either rat Agt or Nrf2 gene promoter, were also studied. Cat overexpression normalized systolic BP, attenuated renal injury, and inhibited RPTC Nrf2, Agt, and heme oxygenase-1 (HO-1) gene expression in Akita Cat transgenic mice compared with Akita mice. In vitro, high glucose level, hydrogen peroxide, and oltipraz stimulated Nrf2 and Agt gene expression; these changes were blocked by trigonelline, small interfering RNAs of Nrf2, antioxidants, or pharmacological inhibitors of nuclear factor-κB and p38 mitogen-activated protein kinase. The deletion of Nrf2-responsive elements in the rat Agt gene promoter abolished the stimulatory effect of oltipraz. Oltipraz administration also augmented Agt, HO-1, and Nrf2 gene expression in mouse RPTCs and was reversed by trigonelline. These data identify a novel mechanism, Nrf2-mediated stimulation of intrarenal Agt gene expression and activation of the renin-angiotensin system, by which hyperglycemia induces hypertension and renal injury in diabetic mice. © 2014 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered.

Crystal structure of human protein kinase CK2

DEFF Research Database (Denmark)

Niefind, K; Guerra, B; Ermakowa, I

2001-01-01

The crystal structure of a fully active form of human protein kinase CK2 (casein kinase 2) consisting of two C-terminally truncated catalytic and two regulatory subunits has been determined at 3.1 A resolution. In the CK2 complex the regulatory subunits form a stable dimer linking the two catalyt...... as a docking partner for various protein kinases. Furthermore it shows an inter-domain mobility in the catalytic subunit known to be functionally important in protein kinases and detected here for the first time directly within one crystal structure.......The crystal structure of a fully active form of human protein kinase CK2 (casein kinase 2) consisting of two C-terminally truncated catalytic and two regulatory subunits has been determined at 3.1 A resolution. In the CK2 complex the regulatory subunits form a stable dimer linking the two catalytic...... subunits, which make no direct contact with one another. Each catalytic subunit interacts with both regulatory chains, predominantly via an extended C-terminal tail of the regulatory subunit. The CK2 structure is consistent with its constitutive activity and with a flexible role of the regulatory subunit...

A lipid binding domain in sphingosine kinase 2

International Nuclear Information System (INIS)

Don, Anthony S.; Rosen, Hugh

2009-01-01

The lipid second messenger sphingosine 1-phosphate (S1P) is a critical mediator of cellular proliferation and survival signals, and is essential for vasculogenesis and neurogenesis. S1P formation is catalysed by sphingosine kinases 1 and 2 (Sphk1 and Sphk2). We have found that the endogenous glycolipid sulfatide (3-O-sulfogalactosylceramide) binds to and inhibits the activity of Sphk2 and the closely related ceramide kinase (Cerk), but not Sphk1. Using sulfatide as a probe, we mapped the lipid binding domain to the N-terminus of Sphk2 (residues 1-175), a region of sequence that is absent in Sphk1, but aligns with a pleckstrin homology domain in Cerk. Accordingly, Sphk2 bound to phosphatidylinositol monophosphates but not to abundant cellular phospholipids. Deleting the N-terminal domain reduced Sphk2 membrane localisation in cells. We have therefore identified a lipid binding domain in Sphk2 that is important for the enzyme's sub-cellular localisation.

Nuclear calcium signaling induces expression of the synaptic organizers Lrrtm1 and Lrrtm2.

Science.gov (United States)

Hayer, Stefanie N; Bading, Hilmar

2015-02-27

Calcium transients in the cell nucleus evoked by synaptic activity in hippocampal neurons function as a signaling end point in synapse-to-nucleus communication. As an important regulator of neuronal gene expression, nuclear calcium is involved in the conversion of synaptic stimuli into functional and structural changes of neurons. Here we identify two synaptic organizers, Lrrtm1 and Lrrtm2, as targets of nuclear calcium signaling. Expression of both Lrrtm1 and Lrrtm2 increased in a synaptic NMDA receptor- and nuclear calcium-dependent manner in hippocampal neurons within 2-4 h after the induction of action potential bursting. Induction of Lrrtm1 and Lrrtm2 occurred independently of the need for new protein synthesis and required calcium/calmodulin-dependent protein kinases and the nuclear calcium signaling target CREB-binding protein. Analysis of reporter gene constructs revealed a functional cAMP response element in the proximal promoter of Lrrtm2, indicating that at least Lrrtm2 is regulated by the classical nuclear Ca(2+)/calmodulin-dependent protein kinase IV-CREB/CREB-binding protein pathway. These results suggest that one mechanism by which nuclear calcium signaling controls neuronal network function is by regulating the expression of Lrrtm1 and Lrrtm2. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Nuclear Calcium Signaling Induces Expression of the Synaptic Organizers Lrrtm1 and Lrrtm2*

Science.gov (United States)

Hayer, Stefanie N.; Bading, Hilmar

2015-01-01

Calcium transients in the cell nucleus evoked by synaptic activity in hippocampal neurons function as a signaling end point in synapse-to-nucleus communication. As an important regulator of neuronal gene expression, nuclear calcium is involved in the conversion of synaptic stimuli into functional and structural changes of neurons. Here we identify two synaptic organizers, Lrrtm1 and Lrrtm2, as targets of nuclear calcium signaling. Expression of both Lrrtm1 and Lrrtm2 increased in a synaptic NMDA receptor- and nuclear calcium-dependent manner in hippocampal neurons within 2–4 h after the induction of action potential bursting. Induction of Lrrtm1 and Lrrtm2 occurred independently of the need for new protein synthesis and required calcium/calmodulin-dependent protein kinases and the nuclear calcium signaling target CREB-binding protein. Analysis of reporter gene constructs revealed a functional cAMP response element in the proximal promoter of Lrrtm2, indicating that at least Lrrtm2 is regulated by the classical nuclear Ca2+/calmodulin-dependent protein kinase IV-CREB/CREB-binding protein pathway. These results suggest that one mechanism by which nuclear calcium signaling controls neuronal network function is by regulating the expression of Lrrtm1 and Lrrtm2. PMID:25527504

Arabidopsis decuple mutant reveals the importance of SnRK2 kinases in osmotic stress responses in vivo

KAUST Repository

Fujii, Hiroaki; Verslues, Paul E.; Zhu, Jian-Kang

2011-01-01

Osmotic stress associated with drought or salinity is a major factor that limits plant productivity. Protein kinases in the SNF1-related protein kinase 2 (SnRK2) family are activated by osmotic stress, suggesting that the kinases are involved

Luteolin suppresses cancer cell proliferation by targeting vaccinia-related kinase 1.

Directory of Open Access Journals (Sweden)

Ye Seul Kim

Full Text Available Uncontrolled proliferation, a major feature of cancer cells, is often triggered by the malfunction of cell cycle regulators such as protein kinases. Recently, cell cycle-related protein kinases have become attractive targets for anti-cancer therapy, because they play fundamental roles in cellular proliferation. However, the protein kinase-targeted drugs that have been developed so far do not show impressive clinical results and also display severe side effects; therefore, there is undoubtedly a need to investigate new drugs targeting other protein kinases that are critical in cell cycle progression. Vaccinia-related kinase 1 (VRK1 is a mitotic kinase that functions in cell cycle regulation by phosphorylating cell cycle-related substrates such as barrier-to-autointegration factor (BAF, histone H3, and the cAMP response element (CRE-binding protein (CREB. In our study, we identified luteolin as the inhibitor of VRK1 by screening a small-molecule natural compound library. Here, we evaluated the efficacy of luteolin as a VRK1-targeted inhibitor for developing an effective anti-cancer strategy. We confirmed that luteolin significantly reduces VRK1-mediated phosphorylation of the cell cycle-related substrates BAF and histone H3, and directly interacts with the catalytic domain of VRK1. In addition, luteolin regulates cell cycle progression by modulating VRK1 activity, leading to the suppression of cancer cell proliferation and the induction of apoptosis. Therefore, our study suggests that luteolin-induced VRK1 inhibition may contribute to establish a novel cell cycle-targeted strategy for anti-cancer therapy.

Speeding through cell cycle roadblocks: Nuclear cyclin D1-dependent kinase and neoplastic transformation

Directory of Open Access Journals (Sweden)

Diehl J Alan

2008-09-01

Full Text Available Abstract Mitogenic induction of cyclin D1, the allosteric regulator of CDK4/6, is a key regulatory event contributing to G1 phase progression. Following the G1/S transition, cyclin D1 activation is antagonized by GSK3β-dependent threonine-286 (Thr-286 phosphorylation, triggering nuclear export and subsequent cytoplasmic degradation mediated by the SCFFbx4-αBcrystallin E3 ubiquitin ligase. Although cyclin D1 overexpression occurs in numerous malignancies, overexpression of cyclin D1 alone is insufficient to drive transformation. In contrast, cyclin D1 mutants refractory to phosphorylation-dependent nuclear export and degradation are acutely transforming. This raises the question of whether overexpression of cyclin D1 is a significant contributor to tumorigenesis or an effect of neoplastic transformation. Significantly, recent work strongly supports a model wherein nuclear accumulation of cyclin D1-dependent kinase during S-phase is a critical event with regard to transformation. The identification of mutations within SCFFbx4-αBcrystallin ligase in primary tumors provides mechanistic insight into cyclin D1 accumulation in human cancer. Furthermore, analysis of mouse models expressing cyclin D1 mutants refractory to degradation indicate that nuclear cyclin D1/CDK4 kinase triggers DNA re-replication and genomic instability. Collectively, these new findings provide a mechanism whereby aberrations in post-translational regulation of cyclin D1 establish a cellular environment conducive to mutations that favor neoplastic growth.

DNA Protecting Activities of Nymphaea nouchali (Burm. f Flower Extract Attenuate t-BHP-Induced Oxidative Stress Cell Death through Nrf2-Mediated Induction of Heme Oxygenase-1 Expression by Activating MAP-Kinases

Directory of Open Access Journals (Sweden)

Md Badrul Alam

2017-09-01

Full Text Available This study was performed to investigate the antioxidant activities of Nymphaea nouchali flower (NNF extract and the underlying mechanism using RAW 264.7 cells. The presence of gallic acid, catechin, epicatechin, epigallocatechin, epicatechin gallate, caffeic acid, quercetin, and apigenin in the NNF was confirmed by high-performance liquid chromatography (HPLC. The extract had a very potent capacity to scavenge numerous free radicals. NNF extract was also able to prevent DNA damage and quench cellular reactive oxygen species (ROS generation induced by tert-Butyl hydroperoxide (t-BHP with no signs of toxicity. The NNF extract was able to augment the expression of both primary and phase II detoxifying enzyme, resulting in combat the oxidative stress. This is accomplished by phosphorylation of mitogen-activated protein kinase (MAP kinase (p38 kinase and extracellular signal-regulated kinase (ERK followed by enhancing the nuclear translocation of the nuclear factor erythroid 2-related factor 2 (Nrf2. This attenuates cellular ROS generation and confers protection from cell death. Altogether, the results of current study revealed that Nymphaea nouchali flower could be a source of natural phytochemicals that could lead to the development of new therapeutic agents for preventing oxidative stress associated diseases and attenuating disease progression.

Protein kinase N2 regulates AMP kinase signaling and insulin responsiveness of glucose metabolism in skeletal muscle.

Science.gov (United States)

Ruby, Maxwell A; Riedl, Isabelle; Massart, Julie; Åhlin, Marcus; Zierath, Juleen R

2017-10-01

Insulin resistance is central to the development of type 2 diabetes and related metabolic disorders. Because skeletal muscle is responsible for the majority of whole body insulin-stimulated glucose uptake, regulation of glucose metabolism in this tissue is of particular importance. Although Rho GTPases and many of their affecters influence skeletal muscle metabolism, there is a paucity of information on the protein kinase N (PKN) family of serine/threonine protein kinases. We investigated the impact of PKN2 on insulin signaling and glucose metabolism in primary human skeletal muscle cells in vitro and mouse tibialis anterior muscle in vivo. PKN2 knockdown in vitro decreased insulin-stimulated glucose uptake, incorporation into glycogen, and oxidation. PKN2 siRNA increased 5'-adenosine monophosphate-activated protein kinase (AMPK) signaling while stimulating fatty acid oxidation and incorporation into triglycerides and decreasing protein synthesis. At the transcriptional level, PKN2 knockdown increased expression of PGC-1α and SREBP-1c and their target genes. In mature skeletal muscle, in vivo PKN2 knockdown decreased glucose uptake and increased AMPK phosphorylation. Thus, PKN2 alters key signaling pathways and transcriptional networks to regulate glucose and lipid metabolism. Identification of PKN2 as a novel regulator of insulin and AMPK signaling may provide an avenue for manipulation of skeletal muscle metabolism. Copyright © 2017 the American Physiological Society.

Diacylglycerol kinase regulation of protein kinase D during oxidative stress-induced intestinal cell injury

International Nuclear Information System (INIS)

Song Jun; Li Jing; Mourot, Joshua M.; Mark Evers, B.; Chung, Dai H.

2008-01-01

We recently demonstrated that protein kinase D (PKD) exerts a protective function during oxidative stress-induced intestinal epithelial cell injury; however, the exact role of DAG kinase (DGK)ζ, an isoform expressed in intestine, during this process is unknown. We sought to determine the role of DGK during oxidative stress-induced intestinal cell injury and whether DGK acts as an upstream regulator of PKD. Inhibition of DGK with R59022 compound or DGKζ siRNA transfection decreased H 2 O 2 -induced RIE-1 cell apoptosis as measured by DNA fragmentation and increased PKD phosphorylation. Overexpression of kinase-dead DGKζ also significantly increased PKD phosphorylation. Additionally, endogenous nuclear DGKζ rapidly translocated to the cytoplasm following H 2 O 2 treatment. Our findings demonstrate that DGK is involved in the regulation of oxidative stress-induced intestinal cell injury. PKD activation is induced by DGKζ, suggesting DGK is an upstream regulator of oxidative stress-induced activation of the PKD signaling pathway in intestinal epithelial cells

Fisetin Ameliorated Photodamage by Suppressing the Mitogen-Activated Protein Kinase/Matrix Metalloproteinase Pathway and Nuclear Factor-κB Pathways.

Science.gov (United States)

Chiang, Hsiu-Mei; Chan, Shih-Yun; Chu, Yin; Wen, Kuo-Ching

2015-05-13

Ultraviolet (UV) irradiation is one of the most important extrinsic factors contributing to skin photodamage. After UV irradiation, a series of signal transductions in the skin will be activated, leading to inflammatory response and photoaged skin. In this study, fisetin, a flavonol that exists in fruits and vegetables, was investigated for its photoprotective effects. The results revealed that 5-25 μM fisetin inhibits cyclooxygenase-2 (COX-2) and matrix metalloproteinase (MMP)-1, MMP-3, MMP-9 expression induced by ultraviolet B (UVB) irradiation in human skin fibroblasts. In addition, fisetin suppressed UVB-induced collagen degradation. With regard to its effect on upper-stream signal transduction, we found that fisetin reduced the expression of ultraviolet (UV)-induced ERK, JNK, and p38 phosphorylation in the mitogen-activated protein kinase (MAP kinase) pathway. Furthermore, fisetin reduced inhibitor κB (IκB) degradation and increased the amount of p65, which is a major subunit of nuclear factor-κB (NF-κB), in cytoplasm. It also suppressed NF-κB translocated to the nucleus and inhibited cAMP response element-binding protein (CREB) Ser-133 phosphorylation level in the phosphoinositide 3-kinase/protein kinase B/CREB (PI3K/AKT/CREB) pathway. Finally, fisetin inhibited UV-induced intracellular reactive oxygen species (ROS), prostaglandin E2 (PGE2), and nitric oxide (NO) generation. The mentioned effects and mechanisms suggest that fisetin can be used in the development of photoprotective agents.

Phosphatidylinositol 3-Kinase (PI3K) and phosphatidylinositol 3-kinase-related kinase (PIKK) inhibitors: importance of the morpholine ring

Czech Academy of Sciences Publication Activity Database

Andrs, M.; Kobarecny, J.; Jun, D.; Hodný, Zdeněk; Bartek, Jiří; Kuca, K.

2015-01-01

Roč. 58, č. 1 (2015), s. 41-71 ISSN 0022-2623 R&D Projects: GA MŠk(CZ) CZ.1.07/2.3.00/30.0044 Grant - others:University Hospital Hradec Kralove(CZ) 00179906; Faculty of Military Health Sciences, University of Defence(CZ) SV/FVZ201402 Institutional support: RVO:68378050 Keywords : DEPENDENT PROTEIN-KINASE * STRAND BREAK REPAIR * SELECTIVE PI3K-BETA INHIBITORS * TELANGIECTASIA MUTATED KINASE Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 5.589, year: 2015

ABI1 and PP2CA Phosphatases Are Negative Regulators of Snf1-Related Protein Kinase1 Signaling in Arabidopsis

OpenAIRE

Rodrigues, A.; Adamo, M.; Crozet, P.; Margalha, L.; Confraria, A.; Martinho, C.; Elias, A.; Rabissi, A.; Lumbreras, V.; Gonzalez-Guzman, M.; Antoni, R.; Rodriguez, P. L.; Baena-Gonzalez, E.

2013-01-01

Plant survival under environmental stress requires the integration of multiple signaling pathways into a coordinated response, but the molecular mechanisms underlying this integration are poorly understood. Stress-derived energy deprivation activates the Snf1-related protein kinases1 (SnRK1s), triggering a vast transcriptional and metabolic reprogramming that restores homeostasis and promotes tolerance to adverse conditions. Here, we show that two clade A type 2C protein phosphatases (PP2Cs),...

The NDR kinase scaffold HYM1/MO25 is essential for MAK2 map kinase signaling in Neurospora crassa.

Directory of Open Access Journals (Sweden)

Anne Dettmann

2012-09-01

Full Text Available Cell communication is essential for eukaryotic development, but our knowledge of molecules and mechanisms required for intercellular communication is fragmentary. In particular, the connection between signal sensing and regulation of cell polarity is poorly understood. In the filamentous ascomycete Neurospora crassa, germinating spores mutually attract each other and subsequently fuse. During these tropic interactions, the two communicating cells rapidly alternate between two different physiological states, probably associated with signal delivery and response. The MAK2 MAP kinase cascade mediates cell-cell signaling. Here, we show that the conserved scaffolding protein HYM1/MO25 controls the cell shape-regulating NDR kinase module as well as the signal-receiving MAP kinase cascade. HYM1 functions as an integral part of the COT1 NDR kinase complex to regulate the interaction with its upstream kinase POD6 and thereby COT1 activity. In addition, HYM1 interacts with NRC1, MEK2, and MAK2, the three kinases of the MAK2 MAP kinase cascade, and co-localizes with MAK2 at the apex of growing cells. During cell fusion, the three kinases of the MAP kinase module as well as HYM1 are recruited to the point of cell-cell contact. hym-1 mutants phenocopy all defects observed for MAK2 pathway mutants by abolishing MAK2 activity. An NRC1-MEK2 fusion protein reconstitutes MAK2 signaling in hym-1, while constitutive activation of NRC1 and MEK2 does not. These data identify HYM1 as a novel regulator of the NRC1-MEK2-MAK2 pathway, which may coordinate NDR and MAP kinase signaling during cell polarity and intercellular communication.

Identification of a novel receptor-like protein kinase that interacts with a geminivirus nuclear shuttle protein

International Nuclear Information System (INIS)

Mariano, Andrea C.; Andrade, Maxuel O.; Santos, Anesia A.; Carolino, Sonia M.B.; Oliveira, Marli L.; Baracat-Pereira, Maria Cristina; Brommonshenkel, Sergio H.; Fontes, Elizabeth P.B.

2004-01-01

Despite extensive studies in plant virus-host interactions, the molecular mechanisms of geminivirus movement and interactions with host components remain largely unknown. A tomato kinase protein and its soybean homolog were found to interact specifically with the nuclear shuttle protein (NSP) of Tomato golden mosaic virus (TGMV) and Tomato crinkle leaf yellows virus (TCrLYV) through yeast two-hybrid screening and in vitro protein binding assays. These proteins, designated LeNIK (Lycopersicon esculentum NSP-Interacting Kinase) and GmNIK (Glycine max NIK), belong to the LRR-RLK (leucine rich-repeat receptor-like kinase) family that is involved in plant developmental processes and/or resistance response. As such, NIK is structurally organized into characteristic domains, including a serine/threonine kinase domain with a nucleotide binding site at the C-terminal region, an internal transmembrane segment and leucine-rich repeats (LRR) at the N-terminal portion. The potential significance of the NSP-NIK interaction is discussed

PSM/SH2-B distributes selected mitogenic receptor signals to distinct components in the PI3-kinase and MAP kinase signaling pathways.

Science.gov (United States)

Deng, Youping; Xu, Hu; Riedel, Heimo

2007-02-15

The Pro-rich, PH, and SH2 domain containing mitogenic signaling adapter PSM/SH2-B has been implicated as a cellular partner of various mitogenic receptor tyrosine kinases and related signaling mechanisms. Here, we report in a direct comparison of three peptide hormones, that PSM participates in the assembly of distinct mitogenic signaling complexes in response to insulin or IGF-I when compared to PDGF in cultured normal fibroblasts. The complex formed in response to insulin or IGF-I involves the respective peptide hormone receptor and presumably the established components leading to MAP kinase activation. However, our data suggest an alternative link from the PDGF receptor via PSM directly to MEK1/2 and consequently also to p44/42 activation, possibly through a scaffold protein. At least two PSM domains participate, the SH2 domain anticipated to link PSM to the respective receptor and the Pro-rich region in an association with an unidentified downstream component resulting in direct MEK1/2 and p44/42 regulation. The PDGF receptor signaling complex formed in response to PDGF involves PI 3-kinase in addition to the same components and interactions as described for insulin or IGF-I. PSM associates with PI 3-kinase via p85 and in addition the PSM PH domain participates in the regulation of PI 3-kinase activity, presumably through membrane interaction. In contrast, the PSM Pro-rich region appears to participate only in the MAP kinase signal. Both pathways contribute to the mitogenic response as shown by cell proliferation, survival, and focus formation. PSM regulates p38 MAP kinase activity in a pathway unrelated to the mitogenic response.

Protein Kinase C-Related Kinase (PKN/PRK). Potential Key-Role for PKN1 in Protection of Hypoxic Neurons.

Science.gov (United States)

Thauerer, Bettina; Zur Nedden, Stephanie; Baier-Bitterlich, Gabriele

2014-05-01

Serine/threonine protein kinase C-related kinase (PKN/PRK) is a family of three isoenzymes (PKN1, PKN2, PKN3), which are widely distributed in eukaryotic organisms and share the same overall domain structure. The Nterminal region encompasses a conserved repeated domain, termed HR1a-c as well as a HR2/C2 domain. The serine/threonine kinase domain is found in the C-terminal region of the protein and shows high sequence homology to other members of the PKC superfamily. In neurons, PKN1 is the most abundant isoform and has been implicated in a variety of functions including cytoskeletal organization and neuronal differentiation and its deregulation may contribute to neuropathological processes such as amyotrophic lateral sclerosis and Alzheimer's disease. We have recently identified a candidate role of PKN1 in the regulation of neuroprotective processes during hypoxic stress. Our key findings were that: 1) the activity of PKN1 was significantly increased by hypoxia (1% O2) and neurotrophins (nerve growth factor and purine nucleosides); 2) Neuronal cells, deficient of PKN1 showed a decrease of cell viability and neurite formation along with a disturbance of the F-actinassociated cytoskeleton; 3) Purine nucleoside-mediated neuroprotection during hypoxia was severely hampered in PKN1 deficient neuronal cells, altogether suggesting a potentially critical role of PKN1 in neuroprotective processes. This review gives an up-to-date overview of the PKN family with a special focus on the neuroprotective role of PKN1 in hypoxia.

SH2 domains: modulators of nonreceptor tyrosine kinase activity

OpenAIRE

Filippakopoulos, Panagis; Müller, Susanne; Knapp, Stefan

2009-01-01

The Src homology 2 (SH2) domain is a sequence-specific phosphotyrosine-binding module present in many signaling molecules. In cytoplasmic tyrosine kinases, the SH2 domain is located N-terminally to the catalytic kinase domain (SH1) where it mediates cellular localization, substrate recruitment, and regulation of kinase activity. Initially, structural studies established a role of the SH2 domain stabilizing the inactive state of Src family members. However, biochemical characterization showed ...

Protein Kinases in Human Breast Carcinoma

National Research Council Canada - National Science Library

Cane, William

1998-01-01

.... Rak is a novel nuclear tyrosine that our group has identified in breast cancer tissues and cell lines that has structural homology to the Src tyrosine kinase, with SH2 and SH3 domains at its amino terminus...

Identification of a nuclear localization signal in the retinitis pigmentosa-mutated RP26 protein, ceramide kinase-like protein

International Nuclear Information System (INIS)

Inagaki, Yuichi; Mitsutake, Susumu; Igarashi, Yasuyuki

2006-01-01

Retinitis pigmentosa (RP) is a genetically heterogeneous disease characterized by degeneration of the retina. A mutation in a new ceramide kinase (CERK) homologous gene, named CERK-like protein (CERKL), was found to cause autosomal recessive retinitis pigmentosa (RP26). Here, we show a point mutation of one of two putative nuclear localization signal (NLS) sequences inhibited the nuclear localization of the protein. Furthermore, the tetra-GFP-tagged NLS, which cannot passively enter the nucleus, was observed not only in the nucleus but also in the nucleolus. Our results provide First evidence of the active nuclear import of CERKL and suggest that the identified NLS might be responsible for nucleolar retention of the protein. As recent studies have shown other RP-related proteins are localized in the nucleus or the nucleolus, our identification of NLS in CERKL suggests that CERKL likely plays important roles for retinal functions in the nucleus and the nucleolus

Ca2+/Calmodulin-Dependent Protein Kinase Kinases (CaMKKs) Effects on AMP-Activated Protein Kinase (AMPK) Regulation of Chicken Sperm Functions.

Science.gov (United States)

Nguyen, Thi Mong Diep; Combarnous, Yves; Praud, Christophe; Duittoz, Anne; Blesbois, Elisabeth

2016-01-01

Sperm require high levels of energy to ensure motility and acrosome reaction (AR) accomplishment. The AMP-activated protein kinase (AMPK) has been demonstrated to be strongly involved in the control of these properties. We address here the question of the potential role of calcium mobilization on AMPK activation and function in chicken sperm through the Ca(2+)/calmodulin-dependent protein kinase kinases (CaMKKs) mediated pathway. The presence of CaMKKs and their substrates CaMKI and CaMKIV was evaluated by western-blotting and indirect immunofluorescence. Sperm were incubated in presence or absence of extracellular Ca(2+), or of CaMKKs inhibitor (STO-609). Phosphorylations of AMPK, CaMKI, and CaMKIV, as well as sperm functions were evaluated. We demonstrate the presence of both CaMKKs (α and β), CaMKI and CaMKIV in chicken sperm. CaMKKα and CaMKI were localized in the acrosome, the midpiece, and at much lower fluorescence in the flagellum, whereas CaMKKβ was mostly localized in the flagellum and much less in the midpiece and the acrosome. CaMKIV was only present in the flagellum. The presence of extracellular calcium induced an increase in kinases phosphorylation and sperm activity. STO-609 reduced AMPK phosphorylation in the presence of extracellular Ca(2+) but not in its absence. STO-609 did not affect CaMKIV phosphorylation but decreased CaMKI phosphorylation and this inhibition was quicker in the presence of extracellular Ca(2+) than in its absence. STO-609 efficiently inhibited sperm motility and AR, both in the presence and absence of extracellular Ca(2+). Our results show for the first time the presence of CaMKKs (α and β) and one of its substrate, CaMKI in different subcellular compartments in germ cells, as well as the changes in the AMPK regulation pathway, sperm motility and AR related to Ca(2+) entry in sperm through the Ca(2+)/CaM/CaMKKs/CaMKI pathway. The Ca(2+)/CaMKKs/AMPK pathway is activated only under conditions of extracellular Ca(2+) entry

Ca2+/Calmodulin-Dependent Protein Kinase Kinases (CaMKKs Effects on AMP-Activated Protein Kinase (AMPK Regulation of Chicken Sperm Functions.

Directory of Open Access Journals (Sweden)

Thi Mong Diep Nguyen

Full Text Available Sperm require high levels of energy to ensure motility and acrosome reaction (AR accomplishment. The AMP-activated protein kinase (AMPK has been demonstrated to be strongly involved in the control of these properties. We address here the question of the potential role of calcium mobilization on AMPK activation and function in chicken sperm through the Ca(2+/calmodulin-dependent protein kinase kinases (CaMKKs mediated pathway. The presence of CaMKKs and their substrates CaMKI and CaMKIV was evaluated by western-blotting and indirect immunofluorescence. Sperm were incubated in presence or absence of extracellular Ca(2+, or of CaMKKs inhibitor (STO-609. Phosphorylations of AMPK, CaMKI, and CaMKIV, as well as sperm functions were evaluated. We demonstrate the presence of both CaMKKs (α and β, CaMKI and CaMKIV in chicken sperm. CaMKKα and CaMKI were localized in the acrosome, the midpiece, and at much lower fluorescence in the flagellum, whereas CaMKKβ was mostly localized in the flagellum and much less in the midpiece and the acrosome. CaMKIV was only present in the flagellum. The presence of extracellular calcium induced an increase in kinases phosphorylation and sperm activity. STO-609 reduced AMPK phosphorylation in the presence of extracellular Ca(2+ but not in its absence. STO-609 did not affect CaMKIV phosphorylation but decreased CaMKI phosphorylation and this inhibition was quicker in the presence of extracellular Ca(2+ than in its absence. STO-609 efficiently inhibited sperm motility and AR, both in the presence and absence of extracellular Ca(2+. Our results show for the first time the presence of CaMKKs (α and β and one of its substrate, CaMKI in different subcellular compartments in germ cells, as well as the changes in the AMPK regulation pathway, sperm motility and AR related to Ca(2+ entry in sperm through the Ca(2+/CaM/CaMKKs/CaMKI pathway. The Ca(2+/CaMKKs/AMPK pathway is activated only under conditions of extracellular Ca(2

Partial purification and characterization of a wortmannin-sensitive and insulin-stimulated protein kinase that activates heart 6-phosphofructo-2-kinase.

OpenAIRE

Deprez, J; Bertrand, L; Alessi, D R; Krause, U; Hue, L; Rider, M H

2000-01-01

A wortmannin-sensitive and insulin-stimulated protein kinase (WISK), which phosphorylates and activates cardiac 6-phosphofructo-2-kinase (PFK-2), was partially purified from perfused rat hearts. Immunoblotting showed that WISK was devoid of protein kinase B (PKB), serum- and glucocorticoid-regulated protein kinase and protein kinase Czeta (PKCzeta). Comparison of the inhibition of WISK, PKCalpha and PKCzeta by different protein kinase inhibitors suggested that WISK was not a member of the PKC...

Extracellular signal-regulated kinases control expression of G protein-coupled receptor kinase 2 (GRK2)

DEFF Research Database (Denmark)

Theilade, Juliane; Lerche Hansen, Jakob; Haunsø, Stig

2002-01-01

G protein-coupled receptor kinase 2 (GRK2) phosphorylates G protein-coupled receptors resulting in uncoupling from G proteins. Receptors modulate GRK2 expression, however the mechanistic basis for this effect is largely unknown. Here we report a novel mechanism by which receptors use...

High-Throughput Screening and Hit Validation of Extracellular-Related Kinase 5 (ERK5) Inhibitors.

Science.gov (United States)

Myers, Stephanie M; Bawn, Ruth H; Bisset, Louise C; Blackburn, Timothy J; Cottyn, Betty; Molyneux, Lauren; Wong, Ai-Ching; Cano, Celine; Clegg, William; Harrington, Ross W; Leung, Hing; Rigoreau, Laurent; Vidot, Sandrine; Golding, Bernard T; Griffin, Roger J; Hammonds, Tim; Newell, David R; Hardcastle, Ian R

2016-08-08

The extracellular-related kinase 5 (ERK5) is a promising target for cancer therapy. A high-throughput screen was developed for ERK5, based on the IMAP FP progressive binding system, and used to identify hits from a library of 57 617 compounds. Four distinct chemical series were evident within the screening hits. Resynthesis and reassay of the hits demonstrated that one series did not return active compounds, whereas three series returned active hits. Structure-activity studies demonstrated that the 4-benzoylpyrrole-2-carboxamide pharmacophore had excellent potential for further development. The minimum kinase binding pharmacophore was identified, and key examples demonstrated good selectivity for ERK5 over p38α kinase.

Sucrose nonfermenting AMPK-related kinase (SNARK) mediates contraction-stimulated glucose transport in mouse skeletal muscle

OpenAIRE

Koh, Ho-Jin; Toyoda, Taro; Fujii, Nobuharu; Jung, Michelle M.; Rathod, Amee; Middelbeek, R. Jan-Willem; Lessard, Sarah J.; Treebak, Jonas T.; Tsuchihara, Katsuya; Esumi, Hiroyasu; Richter, Erik A.; Wojtaszewski, Jørgen F. P.; Hirshman, Michael F.; Goodyear, Laurie J.

2010-01-01

The signaling mechanisms that mediate the important effects of contraction to increase glucose transport in skeletal muscle are not well understood, but are known to occur through an insulin-independent mechanism. Muscle-specific knockout of LKB1, an upstream kinase for AMPK and AMPK-related protein kinases, significantly inhibited contraction-stimulated glucose transport. This finding, in conjunction with previous studies of ablated AMPKα2 activity showing no effect on contraction-stimulated...

Crystal structure of an SH2-kinase construct of c-Abl and effect of the SH2 domain on kinase activity.

Science.gov (United States)

Lorenz, Sonja; Deng, Patricia; Hantschel, Oliver; Superti-Furga, Giulio; Kuriyan, John

2015-06-01

Constitutive activation of the non-receptor tyrosine kinase c-Abl (cellular Abelson tyrosine protein kinase 1, Abl1) in the Bcr (breakpoint cluster region)-Abl1 fusion oncoprotein is the molecular cause of chronic myeloid leukaemia (CML). Recent studies have indicated that an interaction between the SH2 (Src-homology 2) domain and the N-lobe (N-terminal lobe) of the c-Abl kinase domain (KD) has a critical role in leukaemogenesis [Grebien et al. (2011) Cell 147, 306-319; Sherbenou et al. (2010) Blood 116, 3278-3285]. To dissect the structural basis of this phenomenon, we studied c-Abl constructs comprising the SH2 and KDs in vitro. We present a crystal structure of an SH2-KD construct bound to dasatinib, which contains the relevant interface between the SH2 domain and the N-lobe of the KD. We show that the presence of the SH2 domain enhances kinase activity moderately and that this effect depends on contacts in the SH2/N-lobe interface and is abrogated by specific mutations. Consistently, formation of the interface decreases slightly the association rate of imatinib with the KD. That the effects are small compared with the dramatic in vivo consequences suggests an important function of the SH2-N-lobe interaction might be to help disassemble the auto-inhibited conformation of c-Abl and promote processive phosphorylation, rather than substantially stimulate kinase activity.

Overexpression of NIMA-related kinase 2 is associated with poor prognoses in malignant glioma.

Science.gov (United States)

Liu, Huajie; Liu, Bin; Hou, Xianzeng; Pang, Bo; Guo, Pengbo; Jiang, Wanli; Ding, Qian; Zhang, Rui; Xin, Tao; Guo, Hua; Xu, Shangchen; Pang, Qi

2017-05-01

Eleated expression of NIMA-related kinase 2 (NEK2) was frequently observed in a variety of malignant cancers, and it appears to be involved in the initiation, maintenance, progression, metastasis of cancer and is positively associated with poor prognosis. We sought to investigate NEK2 expression and its predictive roles in malignant gliomas, and study the correlation of NEK2 protein expression with proliferation, clinical parameters, overall survival and some other parameters. We investigate NEK2 protein expression in 99 samples of malignant gliomas, including 35 WHO grade II, 22 grade III, and 42 grade IV gliomas, by immunohistochemistry and western blot (n = 50). We then made correlative analysis of protein overexpression using the Kaplan-Meier method, Log rank test, and Cox proportional-hazards model analysis. NEK2 protein was overexpressed in malignant gliomas, but not in normal brain tissues. Overexpression of NEK2 correlated with malignancy, proliferation and adverse overall survival in gliomas. Moreover, chemotherapy, resection extent and WHO grade also correlate with overall survival in gliomas. However, within WHO grade II glioma subgroup, NEK2 overexpression showed no impact on overall survival. The present study firstly reveals that NEK2 protein is widely overexpressed in gliomas. NEK2 overexpression correlates significantly with malignancy (WHO grades), proliferation (Ki-67) and prognosis in malignant gliomas. NEK2 is a potential gene therapy target and prognostic indicator.

Angiogenin-induced protein kinase B/Akt activation is necessary for angiogenesis but is independent of nuclear translocation of angiogenin in HUVE cells

International Nuclear Information System (INIS)

Kim, Hye-Mi; Kang, Dong-Ku; Kim, Hak Yong; Kang, Sang Sun; Chang, Soo-Ik

2007-01-01

Angiogenin, a potent angiogenic factor, binds to endothelial cells and is endocytosed and rapidly translocated to and concentrated in the nucleolus where it binds to DNA. In this study, we report that angiogenin induces transient phosphorylation of protein kinase B/Akt in cultured human umbilical vein endothelial (HUVE) cells. LY294002 inhibits the angiogenin-induced protein kinase B/Akt activation and also angiogenin-induced cell migration in vitro as well as angiogenesis in chick embryo chorioallantoic membrane in vivo without affecting nuclear translocation of angiogenin in HUVE cells. These results suggest that cross-talk between angiogenin and protein kinase B/Akt signaling pathways is essential for angiogenin-induced angiogenesis in vitro and in vivo, and that angiogenin-induced PKB/Akt activation is independent of nuclear translocation of angiogenin in HUVE cells

Expression of the Grb2-related protein of the lymphoid system in B cell subsets enhances B cell antigen receptor signaling through mitogen-activated protein kinase pathways.

Science.gov (United States)

Yankee, Thomas M; Solow, Sasha A; Draves, Kevin D; Clark, Edward A

2003-01-01

Adapter proteins play a critical role in regulating signals triggered by Ag receptor cross-linking. These small molecules link receptor proximal events with downstream signaling pathways. In this study, we explore the expression and function of the Grb2-related protein of the lymphoid system (GrpL)/Grb2-related adaptor downstream of Shc adapter protein in human B cells. GrpL is expressed in naive B cells and is down-regulated following B cell Ag receptor ligation. By contrast, germinal center and memory B cells express little or no GrpL. Using human B cell lines, we detected constitutive interactions between GrpL and B cell linker protein, Src homology (SH)2 domain-containing leukocyte protein of 76 kDa, hemopoietic progenitor kinase 1, and c-Cbl. The N-terminal SH3 domain of GrpL binds c-Cbl while the C-terminal SH3 domain binds B cell linker protein and SH2 domain-containing leukocyte protein of 76 kDa. Exogenous expression of GrpL in a GrpL-negative B cell line leads to enhanced Ag receptor-induced extracellular signal-related kinase and p38 mitogen-activated protein kinase phosphorylation. Thus, GrpL expression in human B cell subsets appears to regulate Ag receptor-mediated signaling events.

SH2-dependent autophosphorylation within the Tec family kinase Itk.

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Joseph, Raji E; Severin, Andrew; Min, Lie; Fulton, D Bruce; Andreotti, Amy H

2009-08-07

The Tec family kinase, Itk (interleukin-2 tyrosine kinase), undergoes an in cis autophosphorylation on Y180 within its Src homology 3 (SH3) domain. Autophosphorylation of the Itk SH3 domain by the Itk kinase domain is strictly dependent on the presence of the intervening Src homology 2 (SH2) domain. A direct docking interaction between the Itk kinase and SH2 domains brings the Itk SH3 domain into the active site where Y180 is then phosphorylated. We now identify the residues on the surface of the Itk SH2 domain responsible for substrate docking and show that this SH2 surface mediates autophosphorylation in the full-length Itk molecule. The canonical phospholigand binding site on the SH2 domain is not involved in substrate docking, instead the docking site consists of side chains from three loop regions (AB, EF and BG) and part of the betaD strand. These results are extended into Btk (Bruton's tyrosine kinase), a Tec family kinase linked to the B-cell deficiency X-linked agammaglobulinemia (XLA). Our results suggest that some XLA-causing mutations might impair Btk phosphorylation.

Pharmacogenetics of telatinib, a VEGFR-2 and VEGFR-3 tyrosine kinase inhibitor, used in patients with solid tumors

NARCIS (Netherlands)

N. Steeghs (Neeltje); A.J. Gelderblom (Hans); J.A.M. Wessels (Judith); F.A.L.M. Eskens (Ferry); N. de Bont (Natasja); J.W. Nortier (Johan); H.J. Guchelaar (Henk Jan)

2011-01-01

textabstractSummary: Purpose Telatinib is an orally active small-molecule tyrosine kinase inhibitor of kinase insert domain receptor (KDR; VEGFR-2) and fms-related tyrosine kinase 4 (FLT4; VEGFR-3). This study aims at the identification of relationships between single nucleotide polymorphisms (SNPs)

A defect in the thymidine kinase 2 gene causing isolated mitochondrial myopathy without mtDNA depletion.

Science.gov (United States)

Leshinsky-Silver, E; Michelson, M; Cohen, S; Ginsberg, M; Sadeh, M; Barash, V; Lerman-Sagie, T; Lev, D

2008-07-01

Isolated mitochondrial myopathies (IMM) are either due to primary defects in mtDNA, in nuclear genes that control mtDNA abundance and structure such as thymidine kinase 2 (TK2), or due to CoQ deficiency. Defects in the TK2 gene have been found to be associated with mtDNA depletion attributed to a depleted mitochondrial dNTP pool in non-dividing cells. We report an unusual case of IMM, homozygous for the H90N mutation in the TK2 gene but unlike other cases with the same mutation, does not demonstrate mtDNA depletion. The patient's clinical course is relatively mild and a muscle biopsy showed ragged red muscle fibers with a mild decrease in complexes I and an increase in complexes IV and II activities. This report extends the phenotypic expression of TK2 defects and suggests that all patients who present with an IMM even with normal quantities of mtDNA should be screened for TK2 mutations.

Gene disruptions indicate an essential function for the LmmCRK1 cdc2-related kinase of Leishmania mexicana.

Science.gov (United States)

Mottram, J C; McCready, B P; Brown, K G; Grant, K M

1996-11-01

The generation of homozygous null mutants for the crk1 Cdc2-Related Kinase of Leishmania mexicana was attempted using targeted gene disruption. Promastigote mutants heterozygous for crk1 were readily isolated with a hyg-targeting fragment, but attempts to create null mutants by second-round transfections with a bie-targeting fragment yielded two classes of mutant, neither of which was null. First, the transfected fragment formed an episome; second, the cloned transfectants were found to contain wild-type crk1 alleles as well as hyg and ble integrations. DNA-content analysis revealed that these mutants were triploid or tetraploid. Plasticity in chromosome number following targeting has been proposed as a means by which Leishmania avoids deletion of essential genes. These data support this theory and implicate crk1 as an essential gene, validating CRK1 as a potential drug target. L mexicana transfected with a Trypanosoma brucel homologue, tbcrk1, was shown to be viable in an immcrk1 null background, thus showing complementation of function between these trypanosomatid genes. The expression of crk1 was further manipulated by engineering a six-histidine tag at the C-terminus of the kinase, allowing purification of the active complex by affinity selection on Nl(2+)-nitriloacetic acid (NTA) agarose.

A double-mutant collection targeting MAP kinase related genes in Arabidopsis for studying genetic interactions.

Science.gov (United States)

Su, Shih-Heng; Krysan, Patrick J

2016-12-01

Mitogen-activated protein kinase cascades are conserved in all eukaryotes. In Arabidopsis thaliana there are approximately 80 genes encoding MAP kinase kinase kinases (MAP3K), 10 genes encoding MAP kinase kinases (MAP2K), and 20 genes encoding MAP kinases (MAPK). Reverse genetic analysis has failed to reveal abnormal phenotypes for a majority of these genes. One strategy for uncovering gene function when single-mutant lines do not produce an informative phenotype is to perform a systematic genetic interaction screen whereby double-mutants are created from a large library of single-mutant lines. Here we describe a new collection of 275 double-mutant lines derived from a library of single-mutants targeting genes related to MAP kinase signaling. To facilitate this study, we developed a high-throughput double-mutant generating pipeline using a system for growing Arabidopsis seedlings in 96-well plates. A quantitative root growth assay was used to screen for evidence of genetic interactions in this double-mutant collection. Our screen revealed four genetic interactions, all of which caused synthetic enhancement of the root growth defects observed in a MAP kinase 4 (MPK4) single-mutant line. Seeds for this double-mutant collection are publicly available through the Arabidopsis Biological Resource Center. Scientists interested in diverse biological processes can now screen this double-mutant collection under a wide range of growth conditions in order to search for additional genetic interactions that may provide new insights into MAP kinase signaling. © 2016 The Authors The Plant Journal © 2016 John Wiley & Sons Ltd.

Nuclear and nucleolar localization signals and their targeting function in phosphatidylinositol 4-kinase PI4K230

International Nuclear Information System (INIS)

Kakuk, Annamaria; Friedlaender, Elza; Vereb, Gyoergy; Lisboa, Duarte; Bagossi, Peter; Toth, Gabor; Gergely, Pal; Vereb, Gyoergy

2008-01-01

PI4K230, an isoform of phosphatidylinositol 4-kinase, known primarily as a cytoplasmic membrane-bound enzyme, was detected recently also in the nucleolus of several cells. Here we provide mechanistic insight on the targeting function of its putative nuclear localization signal (NLS) sequences using molecular modeling, digitonin-permeabilized HeLa cells and binding to various importins. The synthetic sequence 916 NFNHIHKRIRRVADKYLSG 934 comprising a putative monopartite NLS (NLS1), targeted covalently bound fluorescent BSA to the nucleoplasm via classical importin α/β mechanism employing importins α1 and α3 but not α5. This transport was inhibited by wheat germ agglutinin and GTPγS. The sequence 1414 SKKTNRGSQLHKYYMKRRTL 1433 , a putative bipartite NLS (NLS2) proved ineffective in nuclear targeting if conjugated to fluorescently labeled BSA. Nonetheless, NLS2 or either of its basic clusters directed to the nucleolus soybean trypsin inhibitor that can pass the nuclear pore complex passively; moreover, an expressed 58 kDa fragment of PI4K230 (AA1166-1667) comprising NLS2 was also imported into the nucleus by import factors of reticulocyte lysate or by importin α1/β or α3/β complexes and localized to the nucleolus. We conclude that the putative bipartite NLS itself is a nucleolar targeting signal, and for nuclear import PI4K230 requires a larger sequence around it or, alternatively, the monopartite NLS

Genome-wide Identification and Expression Analysis of Calcium-dependent Protein Kinase and Its Closely Related Kinase Genes in Capsicum annuum

Directory of Open Access Journals (Sweden)

hanyang ecai

2015-09-01

Full Text Available As Ca2+ sensors and effectors, calcium-dependent protein kinases (CDPKs play important roles in regulating the downstream components of calcium signaling, which are ubiquitously involved in plant growth, development, and response to environmental cues. However, no CDPKs have been characterized in Capsicum annuum thus far. Herein, a comprehensive analysis of genes encoding pepper CDPKs and CDPK-related protein kinases (CRKs was performed, and 31 CDPK genes and five closely related kinase genes were identified, which were phylogenetically divided into four distinct subfamilies and unevenly distributed across nine chromosomes. Conserved sequence and exon-intron structures were found to be shared by pepper CDPKs within the same subfamily, and the expansion of the CaCPK family in pepper was found to be due to segmental duplication events. Five CDPKs in the Capsicum annuum variety CM334 were found to be mutated in the Chiltepin variety, and one CDPK present in CM334 was lost in Chiltepin. The majority of CDPK and CRK genes were expressed in different pepper tissues and developmental stages, and 10, 12, and eight CDPK genes were transcriptionally modified by salt, heat, and Ralstonia solanacearum stresses, respectively. Furthermore, these genes were found to respond specifically to one stress as well as respond synergistically to two stresses or three stresses, suggesting that these CDPK genes might be involved in the specific or synergistic response of pepper to salt, heat, and R. solanacearum. Our results lay the foundation for future functional characterization of pepper CDPK and its closely related gene families.

Safety related events at nuclear installations in 1995

DEFF Research Database (Denmark)

Korsbech, Uffe C C

1996-01-01

Nuclear safety related events of significance at least corresponding to level 2 of the International Nuclear Event Scale are described. In 1995 only two events occured at nuclear power plants, and four events occured at plants using ionizing radiation for processing or research.......Nuclear safety related events of significance at least corresponding to level 2 of the International Nuclear Event Scale are described. In 1995 only two events occured at nuclear power plants, and four events occured at plants using ionizing radiation for processing or research....

Phosphorylation of sites 3 and 2 in rabbit skeletal muscle glycogen synthase by a multifunctional protein kinase (ATP-citrate lyase kinase)

International Nuclear Information System (INIS)

Sheorain, V.S.; Ramakrishna, S.; Benjamin, W.B.; Soderling, T.R.

1985-01-01

A multifunctional protein kinase, purified from rat liver as ATP-citrate lyase kinase, has been identified as a glycogen synthase kinase. This kinase catalyzed incorporation of up to 1.5 mol of and]2number 2 PO 4 /mol of synthase subunit associated with a decrease in the glycogen synthase activity ratio from 0.85 to a value of 0.15. Approximately 65-70% of the 34 PO 4 was incorporated into site 3 and 30-35% into site 2 as determined by reverse phase high performance liquid chromatography. This multifunctional kinase was distinguished from glycogen synthase kinase-3 on the basis of nucleotide and protein substrate specificities. Since the phosphate contents in glycogen synthase of sites 3 and 2 are altered in diabetes and by insulin administration, the possible involvement of the multifunctional kinase was explored. Glycogen synthase purified from diabetic rabbits was phosphorylated in vitro by this multifunctional kinase at only 10% of the rate compared to synthase purified from control rabbits. Treatment of the diabetics with insulin restored the synthase to a form that was readily phosphorylated in vitro

Targeting the SH2-kinase interface in Bcr-Abl inhibits leukemogenesis.

Science.gov (United States)

Grebien, Florian; Hantschel, Oliver; Wojcik, John; Kaupe, Ines; Kovacic, Boris; Wyrzucki, Arkadiusz M; Gish, Gerald D; Cerny-Reiterer, Sabine; Koide, Akiko; Beug, Hartmut; Pawson, Tony; Valent, Peter; Koide, Shohei; Superti-Furga, Giulio

2011-10-14

Chronic myelogenous leukemia (CML) is caused by the constitutively active tyrosine kinase Bcr-Abl and treated with the tyrosine kinase inhibitor (TKI) imatinib. However, emerging TKI resistance prevents complete cure. Therefore, alternative strategies targeting regulatory modules of Bcr-Abl in addition to the kinase active site are strongly desirable. Here, we show that an intramolecular interaction between the SH2 and kinase domains in Bcr-Abl is both necessary and sufficient for high catalytic activity of the enzyme. Disruption of this interface led to inhibition of downstream events critical for CML signaling and, importantly, completely abolished leukemia formation in mice. Furthermore, disruption of the SH2-kinase interface increased sensitivity of imatinib-resistant Bcr-Abl mutants to TKI inhibition. An engineered Abl SH2-binding fibronectin type III monobody inhibited Bcr-Abl kinase activity both in vitro and in primary CML cells, where it induced apoptosis. This work validates the SH2-kinase interface as an allosteric target for therapeutic intervention. Copyright © 2011 Elsevier Inc. All rights reserved.

2-Aminobenzimidazoles as potent Aurora kinase inhibitors.

Science.gov (United States)

Zhong, Min; Bui, Minna; Shen, Wang; Baskaran, Subramanian; Allen, Darin A; Elling, Robert A; Flanagan, W Michael; Fung, Amy D; Hanan, Emily J; Harris, Shannon O; Heumann, Stacey A; Hoch, Ute; Ivy, Sheryl N; Jacobs, Jeffrey W; Lam, Stuart; Lee, Heman; McDowell, Robert S; Oslob, Johan D; Purkey, Hans E; Romanowski, Michael J; Silverman, Jeffrey A; Tangonan, Bradley T; Taverna, Pietro; Yang, Wenjin; Yoburn, Josh C; Yu, Chul H; Zimmerman, Kristin M; O'Brien, Tom; Lew, Willard

2009-09-01

This Letter describes the discovery and key structure-activity relationship (SAR) of a series of 2-aminobenzimidazoles as potent Aurora kinase inhibitors. 2-Aminobenzimidazole serves as a bioisostere of the biaryl urea residue of SNS-314 (1c), which is a potent Aurora kinase inhibitor and entered clinical testing in patients with solid tumors. Compared to SNS-314, this series of compounds offers better aqueous solubility while retaining comparable in vitro potency in biochemical and cell-based assays; in particular, 6m has also demonstrated a comparable mouse iv PK profile to SNS-314.

A retroviral oncogene, akt, encoding a serine-threonine kinase containing an SH2-like region.

Science.gov (United States)

Bellacosa, A; Testa, J R; Staal, S P; Tsichlis, P N

1991-10-11

The v-akt oncogene codes for a 105-kilodalton fusion phosphoprotein containing Gag sequences at its amino terminus. Sequence analysis of v-akt and biochemical characterization of its product revealed that it codes for a protein kinase C-related serine-threonine kinase whose cellular homolog is expressed in most tissues, with the highest amount found in thymus. Although Akt is a serine-threonine kinase, part of its regulatory region is similar to the Src homology-2 domain, a structural motif characteristic of cytoplasmic tyrosine kinases that functions in protein-protein interactions. This suggests that Akt may form a functional link between tyrosine and serine-threonine phosphorylation pathways.

Clonorchis sinensis excretory-secretory products regulate migration and invasion in cholangiocarcinoma cells via extracellular signal-regulated kinase 1/2/nuclear factor-κB-dependent matrix metalloproteinase-9 expression.

Science.gov (United States)

Pak, Jhang Ho; Shin, Jimin; Song, In-Sung; Shim, Sungbo; Jang, Sung-Wuk

2017-01-01

Matrix metalloproteinase-9 plays an important role in the invasion and metastasis of various types of cancer cells. We have previously reported that excretory-secretory products from Clonorchis sinensis increases matrix metalloproteinase-9 expression. However, the regulatory mechanisms through which matrix metalloproteinase-9 expression affects cholangiocarcinoma development remain unclear. In the current study, we examined the potential role of excretory-secretory products in regulating the migration and invasion of various cholangiocarcinoma cell lines. We demonstrated that excretory-secretory products significantly induced matrix metalloproteinase-9 expression and activity in a concentration-dependent manner. Reporter gene and chromatin immunoprecipitation assays showed that excretory-secretory products induced matrix metalloproteinase-9 expression by enhancing the activity of nuclear factor-kappa B. Moreover, excretory-secretory products induced the degradation and phosphorylation of IκBα and stimulated nuclear factor-kappa B p65 nuclear translocation, which was regulated by extracellular signal-regulated kinase 1/2. Taken together, our findings indicated that the excretory-secretory product-dependent enhancement of matrix metalloproteinase-9 activity and subsequent induction of IκBα and nuclear factor-kappa B activities may contribute to the progression of cholangiocarcinoma. Copyright © 2016 Australian Society for Parasitology. Published by Elsevier Ltd. All rights reserved.

Chronic SO2 inhalation above environmental standard impairs neuronal behavior and represses glutamate receptor gene expression and memory-related kinase activation via neuroinflammation in rats.

Science.gov (United States)

Yao, Gaoyi; Yue, Huifeng; Yun, Yang; Sang, Nan

2015-02-01

Sulfur dioxide (SO2), as a ubiquitous air pollutant implicated in the genesis of pulmonary disease, is now being considered to be involved in neurotoxicity and increased risk for hospitalization of brain disorders. However, comparatively little is known about the impact of chronically SO2 inhalation on neuronal function. In the present study, by exposing male Wistar rats to SO2 at 3.50 and 7.00 mg/m(3) (approximately 1225 and 2450 ppb, 4.08-8.16 (24h average concentration) times higher than the EPA standard for environmental air concentrations) or filtered air for 90 days, we investigated the impact of chronic SO2 inhalation on performance in Morris water maze, and probed the accompanying neurobiological effects, including activity-regulated cytoskeletal associated gene (Arc) and glutamate receptor gene expression, memory-related kinase level and inflammatory cytokine release in the hippocampus. Here, we found that SO2 exposure reduced the number of target zone crossings and time spent in the target quadrant during the test session in the spatial memory retention of the Morris water maze. Following the neuro-functional abnormality, we detected that SO2 inhalation reduced the expression of Arc and glutamate receptor subunits (GluR1, GluR2, NR1, NR2A, and NR2B) with a concentration-dependent property in comparison to controls. Additionally, the expression of memory kinases was attenuated statistically in the animals receiving the higher concentration, including protein kinase A (PKA), protein kinase C (PKC) and calcium/calmodulin-dependent protein kinaseIIα (CaMKIIα). And the inflammatory cytokine release was increased in rats exposed to SO2. Taken together, our results suggest that long-term exposure to SO2 air pollution at concentrations above the environmental standard in rats impaired spatial learning and memory, and indicate a close link between the neurobiological changes highlighted in the brain and the behavioral disturbances. Copyright © 2014 Elsevier Inc

The interaction between tropomyosin-related kinase B receptors and serine kinases modulates acetylcholine release in adult neuromuscular junctions.

Science.gov (United States)

Santafé, Manel M; Garcia, Neus; Tomàs, Marta; Obis, Teresa; Lanuza, Maria A; Besalduch, Nuria; Tomàs, Josep

2014-02-21

We conducted an electrophysiological study of the functional link between the tropomyosin-related kinase B (trkB) receptor signaling mechanism and serine-threonine kinases, both protein kinase C (PKC) and protein kinase A (PKA). We describe their coordinated role in transmitter release at the neuromuscular junction (NMJ) of the Levator auris longus muscle of the adult mouse. The trkB receptor normally seems to be coupled to stimulate ACh release because inhibiting the trkB receptor with K-252a results in a significant reduction in the size of EPPs. We found that the intracellular PKC pathway can operate as in basal conditions (to potentiate ACh release) without the involvement of the trkB receptor function, although the trkB pathway needs an operative PKC pathway if it is to couple to the release mechanism and potentiate it. To actively stimulate PKA (which also results in ACh release potentiation), the operativity of trkB is a necessary condition, and one effect of trkB may be PKA stimulation. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Control of cytoplasmic and nuclear protein kinase A by phosphodiesterases and phosphatases in cardiac myocytes

Science.gov (United States)

Haj Slimane, Zeineb; Bedioune, Ibrahim; Lechêne, Patrick; Varin, Audrey; Lefebvre, Florence; Mateo, Philippe; Domergue-Dupont, Valérie; Dewenter, Matthias; Richter, Wito; Conti, Marco; El-Armouche, Ali; Zhang, Jin; Fischmeister, Rodolphe; Vandecasteele, Grégoire

2014-01-01

Aims The cAMP-dependent protein kinase (PKA) mediates β-adrenoceptor (β-AR) regulation of cardiac contraction and gene expression. Whereas PKA activity is well characterized in various subcellular compartments of adult cardiomyocytes, its regulation in the nucleus remains largely unknown. The aim of the present study was to compare the modalities of PKA regulation in the cytoplasm and nucleus of cardiomyocytes. Methods and results Cytoplasmic and nuclear cAMP and PKA activity were measured with targeted fluorescence resonance energy transfer probes in adult rat ventricular myocytes. β-AR stimulation with isoprenaline (Iso) led to fast cAMP elevation in both compartments, whereas PKA activity was fast in the cytoplasm but markedly slower in the nucleus. Iso was also more potent and efficient in activating cytoplasmic than nuclear PKA. Similar slow kinetics of nuclear PKA activation was observed upon adenylyl cyclase activation with L-858051 or phosphodiesterase (PDE) inhibition with 3-isobutyl-1-methylxantine. Consistently, pulse stimulation with Iso (15 s) maximally induced PKA and myosin-binding protein C phosphorylation in the cytoplasm, but marginally activated PKA and cAMP response element-binding protein phosphorylation in the nucleus. Inhibition of PDE4 or ablation of the Pde4d gene in mice prolonged cytoplasmic PKA activation and enhanced nuclear PKA responses. In the cytoplasm, phosphatase 1 (PP1) and 2A (PP2A) contributed to the termination of PKA responses, whereas only PP1 played a role in the nucleus. Conclusion Our study reveals a differential integration of cytoplasmic and nuclear PKA responses to β-AR stimulation in cardiac myocytes. This may have important implications in the physiological and pathological hypertrophic response to β-AR stimulation. PMID:24550350

Chitin and stress induced protein kinase activation

DEFF Research Database (Denmark)

Kenchappa, Chandra Shekar; Azevedo da Silva, Raquel; Bressendorff, Simon

2017-01-01

The assays described here are pertinent to protein kinase studies in any plant. They include an immunoblot phosphorylation/activation assay and an in-gel activity assay for MAP kinases (MPKs) using the general protein kinase substrate myelin basic protein. They also include a novel in-gel peptide...... substrate assay for Snf1-related kinase family 2 members (SnRK2s). This kinase family-specific assay overcomes some limitations of in-gel assays and permits the identification of different types of kinase activities in total protein extracts....

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

International Nuclear Information System (INIS)

Bianchi, Cristina; Torsello, Barbara; Di Stefano, Vitalba; Zipeto, Maria A.; Facchetti, Rita; Bombelli, Silvia; Perego, Roberto A.

2013-01-01

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

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.

Tyrosine kinases in rheumatoid arthritis

Directory of Open Access Journals (Sweden)

Kobayashi Akiko

2011-08-01

Full Text Available Abstract Rheumatoid arthritis (RA is an inflammatory, polyarticular joint disease. A number of cellular responses are involved in the pathogenesis of rheumatoid arthritis, including activation of inflammatory cells and cytokine expression. The cellular responses involved in each of these processes depends on the specific signaling pathways that are activated; many of which include protein tyrosine kinases. These pathways include the mitogen-activated protein kinase pathway, Janus kinases/signal transducers and activators transcription pathway, spleen tyrosine kinase signaling, and the nuclear factor κ-light-chain-enhancer of activated B cells pathway. Many drugs are in development to target tyrosine kinases for the treatment of RA. Based on the number of recently published studies, this manuscript reviews the role of tyrosine kinases in the pathogenesis of RA and the potential role of kinase inhibitors as new therapeutic strategies of RA.

Structural basis for activation of ZAP-70 by phosphorylation of the SH2-kinase linker.

Science.gov (United States)

Yan, Qingrong; Barros, Tiago; Visperas, Patrick R; Deindl, Sebastian; Kadlecek, Theresa A; Weiss, Arthur; Kuriyan, John

2013-06-01

Serial activation of the tyrosine kinases Lck and ZAP-70 initiates signaling downstream of the T cell receptor. We previously reported the structure of an autoinhibited ZAP-70 variant in which two regulatory tyrosine residues (315 and 319) in the SH2-kinase linker were replaced by phenylalanine. We now present a crystal structure of ZAP-70 in which Tyr 315 and Tyr 319 are not mutated, leading to the recognition of a five-residue sequence register error in the SH2-kinase linker of the original crystallographic model. The revised model identifies distinct roles for these two tyrosines. As seen in a recently reported structure of the related tyrosine kinase Syk, Tyr 315 of ZAP-70 is part of a hydrophobic interface between the regulatory apparatus and the kinase domain, and the integrity of this interface would be lost upon engagement of doubly phosphorylated peptides by the SH2 domains. Tyr 319 is not necessarily dislodged by SH2 engagement, which activates ZAP-70 only ∼5-fold in vitro. In contrast, phosphorylation by Lck activates ZAP-70 ∼100-fold. This difference is due to the ability of Tyr 319 to suppress ZAP-70 activity even when the SH2 domains are dislodged from the kinase domain, providing stringent control of ZAP-70 activity downstream of Lck.

Structure of Human G Protein-Coupled Receptor Kinase 2 in Complex with the Kinase Inhibitor Balanol

Energy Technology Data Exchange (ETDEWEB)

Tesmer, John J.G.; Tesmer, Valerie M.; Lodowski, David T.; Steinhagen, Henning; Huber, Jochen (Sanofi); (Michigan); (Texas)

2010-07-19

G protein-coupled receptor kinase 2 (GRK2) is a pharmaceutical target for the treatment of cardiovascular diseases such as congestive heart failure, myocardial infarction, and hypertension. To better understand how nanomolar inhibition and selectivity for GRK2 might be achieved, we have determined crystal structures of human GRK2 in complex with G{beta}{gamma} in the presence and absence of the AGC kinase inhibitor balanol. The selectivity of balanol among human GRKs is assessed.

Mitogen-activated protein kinase kinase 1/2 inhibition and angiotensin II converting inhibition in mice with cardiomyopathy caused by lamin A/C gene mutation

Energy Technology Data Exchange (ETDEWEB)

Muchir, Antoine, E-mail: a.muchir@institut-myologie.org [Department of Medicine, College of Physicians and Surgeons, Columbia University, New York, NY (United States); Department of Pathology and Cell Biology, College of Physicians and Surgeons, Columbia University, New York, NY (United States); Wu, Wei [Department of Medicine, College of Physicians and Surgeons, Columbia University, New York, NY (United States); Department of Pathology and Cell Biology, College of Physicians and Surgeons, Columbia University, New York, NY (United States); Sera, Fusako; Homma, Shunichi [Department of Medicine, College of Physicians and Surgeons, Columbia University, New York, NY (United States); Worman, Howard J., E-mail: hjw14@columbia.edu [Department of Medicine, College of Physicians and Surgeons, Columbia University, New York, NY (United States); Department of Pathology and Cell Biology, College of Physicians and Surgeons, Columbia University, New York, NY (United States)

2014-10-03

Highlights: • Both ACE and MEK1/2 inhibition are beneficial on cardiac function in Lmna cardiomyopathy. • MEK1/2 inhibitor has beneficial effects beyond ACE inhibition for Lmna cardiomyopathy. • These results provide further preclinical rationale for a clinical trial of a MEK1/2 inhibitor. - Abstract: Background: Mutations in the LMNA gene encoding A-type nuclear lamins can cause dilated cardiomyopathy with or without skeletal muscular dystrophy. Previous studies have shown abnormally increased extracellular signal-regulated kinase 1/2 activity in hearts of Lmna{sup H222P/H222P} mice, a small animal model. Inhibition of this abnormal signaling activity with a mitogen-activated protein kinase kinase 1/2 (MEK1/2) inhibitor has beneficial effects on heart function and survival in these mice. However, such treatment has not been examined relative to any standard of care intervention for dilated cardiomyopathy or heart failure. We therefore examined the effects of an angiotensin II converting enzyme (ACE) inhibitor on left ventricular function in Lmna{sup H222P/H222P} mice and assessed if adding a MEK1/2 inhibitor would provide added benefit. Methods: Male Lmna{sup H222P/H222P} mice were treated with the ACE inhibitor benazepril, the MEK1/2 inhibitor selumetinib or both. Transthoracic echocardiography was used to measure left ventricular diameters and fractional shortening was calculated. Results: Treatment of Lmna{sup H222P/H222P} mice with either benazepril or selumetinib started at 8 weeks of age, before the onset of detectable left ventricular dysfunction, lead to statistically significantly increased fractional shortening compared to placebo at 16 weeks of age. There was a trend towards a great value for fractional shortening in the selumetinib-treated mice. When treatment was started at 16 weeks of age, after the onset of left ventricular dysfunction, the addition of selumetinib treatment to benazepril lead to a statistically significant increase in left

Mitogen-activated protein kinase kinase 1/2 inhibition and angiotensin II converting inhibition in mice with cardiomyopathy caused by lamin A/C gene mutation

International Nuclear Information System (INIS)

Muchir, Antoine; Wu, Wei; Sera, Fusako; Homma, Shunichi; Worman, Howard J.

2014-01-01

Highlights: • Both ACE and MEK1/2 inhibition are beneficial on cardiac function in Lmna cardiomyopathy. • MEK1/2 inhibitor has beneficial effects beyond ACE inhibition for Lmna cardiomyopathy. • These results provide further preclinical rationale for a clinical trial of a MEK1/2 inhibitor. - Abstract: Background: Mutations in the LMNA gene encoding A-type nuclear lamins can cause dilated cardiomyopathy with or without skeletal muscular dystrophy. Previous studies have shown abnormally increased extracellular signal-regulated kinase 1/2 activity in hearts of Lmna H222P/H222P mice, a small animal model. Inhibition of this abnormal signaling activity with a mitogen-activated protein kinase kinase 1/2 (MEK1/2) inhibitor has beneficial effects on heart function and survival in these mice. However, such treatment has not been examined relative to any standard of care intervention for dilated cardiomyopathy or heart failure. We therefore examined the effects of an angiotensin II converting enzyme (ACE) inhibitor on left ventricular function in Lmna H222P/H222P mice and assessed if adding a MEK1/2 inhibitor would provide added benefit. Methods: Male Lmna H222P/H222P mice were treated with the ACE inhibitor benazepril, the MEK1/2 inhibitor selumetinib or both. Transthoracic echocardiography was used to measure left ventricular diameters and fractional shortening was calculated. Results: Treatment of Lmna H222P/H222P mice with either benazepril or selumetinib started at 8 weeks of age, before the onset of detectable left ventricular dysfunction, lead to statistically significantly increased fractional shortening compared to placebo at 16 weeks of age. There was a trend towards a great value for fractional shortening in the selumetinib-treated mice. When treatment was started at 16 weeks of age, after the onset of left ventricular dysfunction, the addition of selumetinib treatment to benazepril lead to a statistically significant increase in left ventricular fractional

Unchanged thymidine triphosphate pools and thymidine metabolism in two lines of thymidine kinase 2-mutated fibroblasts.

Science.gov (United States)

Frangini, Miriam; Rampazzo, Chiara; Franzolin, Elisa; Lara, Mari-Carmen; Vilà, Maya R; Martí, Ramon; Bianchi, Vera

2009-02-01

Mitochondrial thymidine kinase (TK2) catalyzes the phosphorylation of thymidine in mitochondria. Its function becomes essential for dTTP synthesis in noncycling cells, where cytosolic dTTP synthesis via R1/R2 ribonucleotide reductase and thymidine kinase 1 is turned down. Mutations in the nuclear gene for TK2 cause a fatal mtDNA depletion syndrome. Only selected cell types are affected, suggesting that the other cells compensate for the TK2 deficiency by adapting the enzyme network that regulates dTTP synthesis outside S-phase. Here we looked for such metabolic adaptation in quiescent cultures of fibroblasts from two TK2-deficient patients with a slow-progressing syndrome. In cell extracts, we measured the activities of TK2, deoxycytidine kinase, thymidine phosphorylase, deoxynucleotidases and the amounts of the three ribonucleotide reductase subunits. Patient cells contained 40% or 5% TK2 activity and unchanged activities of the other enzymes. However, their mitochondrial and cytosolic dTTP pools were unchanged, and also the overall composition of the dNTP pools was normal. TK2-dependent phosphorylation of [(3)H]thymidine in intact cells and the turnover of the dTTP pool showed that even the fibroblasts with 5% residual TK2 activity synthesized dTTP at an almost normal rate. Normal fibroblasts apparently contain more TK2 than needed to maintain dTTP during quiescence, which would explain why TK2-mutated fibroblasts do not manifest mtDNA depletion despite their reduced TK2 activity.

Significance of host cell kinases in herpes simplex virus type 1 egress and lamin-associated protein disassembly from the nuclear lamina

International Nuclear Information System (INIS)

Leach, Natalie R.; Roller, Richard J.

2010-01-01

The nuclear lamina is thought to be a steric barrier to the herpesvirus capsid. Disruption of the lamina accompanied by phosphorylation of lamina proteins is a conserved feature of herpesvirus infection. In HSV-1-infected cells, protein kinase C (PKC) alpha and delta isoforms are recruited to the nuclear membrane and PKC delta has been implicated in phosphorylation of emerin and lamin B. We tested two critical hypotheses about the mechanism and significance of lamina disruption. First, we show that chemical inhibition of all PKC isoforms reduced viral growth five-fold and inhibited capsid egress from the nucleus. However, specific inhibition of either conventional PKCs or PKC delta does not inhibit viral growth. Second, we show hyperphosphorylation of emerin by viral and cellular kinases is required for its disassociation from the lamina. These data support hypothesis that phosphorylation of lamina components mediates lamina disruption during HSV nuclear egress.

Cordyceps militaris Fraction induces apoptosis and G2/M Arrest via c-Jun N-Terminal kinase signaling pathway in oral squamous carcinoma KB Cells.

Science.gov (United States)

Xie, Wangshi; Zhang, Zhang; Song, Liyan; Huang, Chunhua; Guo, Zhongyi; Hu, Xianjing; Bi, Sixue; Yu, Rongmin

2018-01-01

Cordyceps militaris fraction (CMF) has been shown to possess in vitro antitumor activity against human chronic myeloid leukemia K562 cells in our previous research. The in vitro inhibitory activities of CMF on the growth of KB cells were evaluated by viability assay. The apoptotic and cell cycle influences of CMF were detected by 4',6-diamidino-2-phenylindole staining and flow cytometry assay. The expression of different apoptosis-associated proteins and cell cycle regulatory proteins was examined by Western blot assay. The nuclear localization of c-Jun was observed by fluorescence staining. The objective of this study was to investigate the antiproliferative effect of CMF as well as the mechanism underlying the apoptosis and cell cycle arrest it induces in KB cells. CMF suppressed KB cells' proliferation in a dose- and time-dependent manner. Flow cytometric analysis indicated that CMF induced G2/M cell cycle arrest and apoptosis. Western blot analysis revealed that CMF induced caspase-3, caspase-9, and PARP cleavages, and increased the Bax/Bcl-2 ratio. CMF also led to increased expression of p21, decreased expression of cyclin B1, mitotic phosphatase cdc25c, and mitotic kinase cdc2, as well as unchanged expression of p53. In addition, CMF stimulated c-Jun N-terminal kinases (JNK) protein phosphorylations, resulting in upregulated expression of c-Jun and nuclear localization of c-Jun. Pretreatment with JNK inhibitor SP600125 suppressed CMF-induced apoptosis and G2/M arrest. CMF is capable of modulating c-Jun caspase and Bcl-2 family proteins through JNK-dependent apoptosis, which results in G2/M phase arrest in KB cells. CMF could be developed as a promising candidate for the new antitumor agents. CMF exhibited strong anticancer activity against oral squamous carcinoma KB cellsCMF inhibited KB cells' proliferation via induction of apoptosis and G2/M cell cycle arrestCMF activated JNK signaling pathway and promoted the nuclear localization of c-JunCMF regulated the

Inflammatory Signaling by NOD-RIPK2 Is Inhibited by Clinically Relevant Type II Kinase Inhibitors.

Science.gov (United States)

Canning, Peter; Ruan, Qui; Schwerd, Tobias; Hrdinka, Matous; Maki, Jenny L; Saleh, Danish; Suebsuwong, Chalada; Ray, Soumya; Brennan, Paul E; Cuny, Gregory D; Uhlig, Holm H; Gyrd-Hansen, Mads; Degterev, Alexei; Bullock, Alex N

2015-09-17

RIPK2 mediates pro-inflammatory signaling from the bacterial sensors NOD1 and NOD2, and is an emerging therapeutic target in autoimmune and inflammatory diseases. We observed that cellular RIPK2 can be potently inhibited by type II inhibitors that displace the kinase activation segment, whereas ATP-competitive type I inhibition was only poorly effective. The most potent RIPK2 inhibitors were the US Food and Drug Administration-approved drugs ponatinib and regorafenib. Their mechanism of action was independent of NOD2 interaction and involved loss of downstream kinase activation as evidenced by lack of RIPK2 autophosphorylation. Notably, these molecules also blocked RIPK2 ubiquitination and, consequently, inflammatory nuclear factor κB signaling. In monocytes, the inhibitors selectively blocked NOD-dependent tumor necrosis factor production without affecting lipopolysaccharide-dependent pathways. We also determined the first crystal structure of RIPK2 bound to ponatinib, and identified an allosteric site for inhibitor development. These results highlight the potential for type II inhibitors to treat indications of RIPK2 activation as well as inflammation-associated cancers. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Expression of casein kinase 2 during mouse embryogenesis

DEFF Research Database (Denmark)

Mestres, P; Boldyreff, B; Ebensperger, C

1994-01-01

This paper deals with the expression and distribution of casein kinase 2 (CK-2) subunits in mouse embryos at different developmental stages. Expression was investigated at the mRNA level of CK-2 alpha- and beta-subunits by in situ hybridization and distribution at the protein level by immunohisto......This paper deals with the expression and distribution of casein kinase 2 (CK-2) subunits in mouse embryos at different developmental stages. Expression was investigated at the mRNA level of CK-2 alpha- and beta-subunits by in situ hybridization and distribution at the protein level...

76 FR 70169 - Draft Supplement 2 to Final Environmental Statement Related to the Operation of Watts Bar Nuclear...

Science.gov (United States)

2011-11-10

... Environmental Statement Related to the Operation of Watts Bar Nuclear Plant, Unit 2; Tennessee Valley Authority... on NUREG-0498, ``Final Environmental Statement, Supplement 2, Related to the Operation of Watts Bar... the Nuclear Regulatory Commission. Stephen J. Campbell, Chief, Watts Bar Special Projects Branch...

Protein kinase A phosphorylates serine 267 in the homeodomain of engrailed-2 leading to decreased DNA binding

DEFF Research Database (Denmark)

Hjerrild, Majbrit; Stensballe, Allan; Jensen, Ole N

2004-01-01

Engrailed-2 (En-2) belongs to an evolutionarily conserved family of DNA binding homeodomain-containing proteins that are expressed in mammalian brain during development. Here, we demonstrate that serine 267 in the homeodomain of En-2 is phosphorylated by protein kinase A (PKA) in forskolin......-treated COS-7 cells. Furthermore, we analyze the physiological function of En-2 phosphorylation by PKA. The nuclear localization of En-2 is not influenced by the phosphorylation of serine 267. However, substitution of serine 267 with alanine resulted in increased binding of En-2 to DNA, while replacing serine...

Blue light-excited LOV1 and LOV2 domains cooperatively regulate the kinase activity of full-length phototropin2 from Arabidopsis.

Science.gov (United States)

Oide, Mao; Okajima, Koji; Nakagami, Hirofumi; Kato, Takayuki; Sekiguchi, Yuki; Oroguchi, Tomotaka; Hikima, Takaaki; Yamamoto, Masaki; Nakasako, Masayoshi

2018-01-19

Phototropin2 (phot2) is a blue-light (BL) receptor that regulates BL-dependent activities for efficient photosynthesis in plants. phot2 comprises two BL-receiving light-oxygen-voltage-sensing domains (LOV1 and LOV2) and a kinase domain. BL-excited LOV2 is thought to be primarily responsible for the BL-dependent activation of the kinase. However, the molecular mechanisms by which small BL-induced conformational changes in the LOV2 domain are transmitted to the kinase remain unclear. Here, we used full-length wild-type and mutant phot2 proteins from Arabidopsis to study their molecular properties in the dark and under BL irradiation. Phosphorylation assays and absorption measurements indicated that the LOV1 domain assists the thermal relaxation of BL-excited LOV2 and vice versa. Using small-angle X-ray scattering and electron microscopy, we observed that phot2 forms a dimer and has a rod shape with a maximum length of 188 Å and a radius of gyration of 44 Å. Under BL, phot2 displayed large conformational changes that bent the rod shape. By superimposing the crystal structures of the LOV1 dimer, LOV2, and a homology model of the kinase to the observed changes, we inferred that the BL-dependent change consisted of positional shifts of both LOV2 and the kinase relative to LOV1. Furthermore, phot2 mutants lacking the photocycle in LOV1 or LOV2 still exhibited conformational changes under BL, suggesting that LOV1 and LOV2 cooperatively contribute to the conformational changes that activate the kinase. These results suggest that BL-activated LOV1 contributes to the kinase activity of phot2. We discuss the possible intramolecular interactions and signaling mechanisms in phot2. © 2018 by The American Society for Biochemistry and Molecular Biology, Inc.

Kinase activation through dimerization by human SH2-B.

Science.gov (United States)

Nishi, Masahiro; Werner, Eric D; Oh, Byung-Chul; Frantz, J Daniel; Dhe-Paganon, Sirano; Hansen, Lone; Lee, Jongsoon; Shoelson, Steven E

2005-04-01

The isoforms of SH2-B, APS, and Lnk form a family of signaling proteins that have been described as activators, mediators, or inhibitors of cytokine and growth factor signaling. We now show that the three alternatively spliced isoforms of human SH2-B readily homodimerize in yeast two-hybrid and cellular transfections assays, and this is mediated specifically by a unique domain in its amino terminus. Consistent with previous reports, we further show that the SH2 domains of SH2-B and APS bind JAK2 at Tyr813. These findings suggested a model in which two molecules of SH2-B or APS homodimerize with their SH2 domains bound to two JAK2 molecules, creating heterotetrameric JAK2-(SH2-B)2-JAK2 or JAK2-(APS)2-JAK2 complexes. We further show that APS and SH2-B isoforms heterodimerize. At lower levels of SH2-B or APS expression, dimerization approximates two JAK2 molecules to induce transactivation. At higher relative concentrations of SH2-B or APS, kinase activation is blocked. SH2-B or APS homodimerization and SH2-B/APS heterodimerization thus provide direct mechanisms for activating and inhibiting JAK2 and other kinases from the inside of the cell and for potentiating or attenuating cytokine and growth factor receptor signaling when ligands are present.

to view fulltext PDF

Indian Academy of Sciences (India)

2013-07-10

Jul 10, 2013 ... then released from the transcription site and gradually move to .... 5′-cap structure by the concerted action of Dcp1p/Dcp2p (called decapping complex) ... involves the mitotic exit network (MEN) kinase Dbf2p and its interacting partner ...... and Upf3p, which in turn promotes the decapping reaction mediated ...

Identification of Open Stomata1-Interacting Proteins Reveals Interactions with Sucrose Non-fermenting1-Related Protein Kinases2 and with Type 2A Protein Phosphatases That Function in Abscisic Acid Responses1[OPEN

Science.gov (United States)

Waadt, Rainer; Manalansan, Bianca; Rauniyar, Navin; Munemasa, Shintaro; Booker, Matthew A.; Brandt, Benjamin; Waadt, Christian; Nusinow, Dmitri A.; Kay, Steve A.; Kunz, Hans-Henning; Schumacher, Karin; DeLong, Alison; Yates, John R.; Schroeder, Julian I.

2015-01-01

The plant hormone abscisic acid (ABA) controls growth and development and regulates plant water status through an established signaling pathway. In the presence of ABA, pyrabactin resistance/regulatory component of ABA receptor proteins inhibit type 2C protein phosphatases (PP2Cs). This, in turn, enables the activation of Sucrose Nonfermenting1-Related Protein Kinases2 (SnRK2). Open Stomata1 (OST1)/SnRK2.6/SRK2E is a major SnRK2-type protein kinase responsible for mediating ABA responses. Arabidopsis (Arabidopsis thaliana) expressing an epitope-tagged OST1 in the recessive ost1-3 mutant background was used for the copurification and identification of OST1-interacting proteins after osmotic stress and ABA treatments. These analyses, which were confirmed using bimolecular fluorescence complementation and coimmunoprecipitation, unexpectedly revealed homo- and heteromerization of OST1 with SnRK2.2, SnRK2.3, OST1, and SnRK2.8. Furthermore, several OST1-complexed proteins were identified as type 2A protein phosphatase (PP2A) subunits and as proteins involved in lipid and galactolipid metabolism. More detailed analyses suggested an interaction network between ABA-activated SnRK2-type protein kinases and several PP2A-type protein phosphatase regulatory subunits. pp2a double mutants exhibited a reduced sensitivity to ABA during seed germination and stomatal closure and an enhanced ABA sensitivity in root growth regulation. These analyses add PP2A-type protein phosphatases as another class of protein phosphatases to the interaction network of SnRK2-type protein kinases. PMID:26175513

Characterization of cyclin-dependent kinases and Cdc2/Cdc28 kinase subunits in Trichomonas vaginalis.

Science.gov (United States)

Amador, Erick; López-Pacheco, Karla; Morales, Nataly; Coria, Roberto; López-Villaseñor, Imelda

2017-04-01

Cyclin-dependent kinases (CDKs) have important roles in regulating key checkpoints between stages of the cell cycle. Their activity is tightly regulated through a variety of mechanisms, including through binding with cyclin proteins and the Cdc2/Cdc28 kinase subunit (CKS), and their phosphorylation at specific amino acids. Studies of the components involved in cell cycle control in parasitic protozoa are limited. Trichomonas vaginalis is the causative agent of trichomoniasis in humans and is therefore important in public health; however, some of the basic biological processes used by this organism have not been defined. Here, we characterized proteins potentially involved in cell cycle regulation in T. vaginalis. Three genes encoding protein kinases were identified in the T. vaginalis genome, and the corresponding recombinant proteins (TvCRK1, TvCRK2, TvCRK5) were studied. These proteins displayed similar sequence features to CDKs. Two genes encoding CKSs were also identified, and the corresponding recombinant proteins were found to interact with TvCRK1 and TvCRK2 by a yeast two-hybrid system. One putative cyclin B protein from T. vaginalis was found to bind to and activate the kinase activities of TvCRK1 and TvCRK5, but not TvCRK2. This work is the first characterization of proteins involved in cell cycle control in T. vaginalis.

Differential binding of RhoA, RhoB, and RhoC to protein kinase C-related kinase (PRK) isoforms PRK1, PRK2, and PRK3: PRKs have the highest affinity for RhoB.

Science.gov (United States)

Hutchinson, Catherine L; Lowe, Peter N; McLaughlin, Stephen H; Mott, Helen R; Owen, Darerca

2013-11-12

Protein kinase C-related kinases (PRKs) are members of the protein kinase C superfamily of serine-threonine kinases and can be activated by binding to members of the Rho family of GTPases via a Rho-binding motif known as an HR1 domain. Three tandem HR1 domains reside at the N-terminus of the PRKs. We have assessed the ability of the HR1a and HR1b domains from the three PRK isoforms (PRK1, PRK2, and PRK3) to interact with the three Rho isoforms (RhoA, RhoB, and RhoC). The affinities of RhoA and RhoC for a construct encompassing both PRK1 HR1 domains were similar to those for the HR1a domain alone, suggesting that these interactions are mediated solely by the HR1a domain. The affinities of RhoB for both the PRK1 HR1a domain and the HR1ab didomain were higher than those of RhoA or RhoC. RhoB also bound more tightly to the didomain than to the HR1a domain alone, implicating the HR1b domain in the interaction. As compared with PRK1 HR1 domains, PRK2 and PRK3 domains bind less well to all Rho isoforms. Uniquely, however, the PRK3 domains display a specificity for RhoB that requires both the C-terminus of RhoB and the PRK3 HR1b domain. The thermal stability of the HR1a and HR1b domains was also investigated. The PRK2 HR1a domain was found to be the most thermally stable, while PRK2 HR1b, PRK3 HR1a, and PRK3 HR1b domains all exhibited lower melting temperatures, similar to that of the PRK1 HR1a domain. The lower thermal stability of the PRK2 and PRK3 HR1b domains may impart greater flexibility, driving their ability to interact with Rho isoforms.

76 FR 80409 - Draft Supplement 2 to Final Environmental Statement Related to the Operation of Watts Bar Nuclear...

Science.gov (United States)

2011-12-23

... Environmental Statement Related to the Operation of Watts Bar Nuclear Plant, Unit 2; Tennessee Valley Authority..., Related to the Operation of Watts Bar Nuclear Plant [WBN], Unit 2--Draft Report for Comment'' (draft SFES.... Stephen J. Campbell, Chief, Watts Bar Special Projects Branch, Division of Operating Reactor Licensing...

Structural basis for basal activity and autoactivation of abscisic acid (ABA) signaling SnRK2 kinases

Energy Technology Data Exchange (ETDEWEB)

Ng, Ley-Moy; Soon, Fen-Fen; Zhou, X. Edward; West, Graham M.; Kovach, Amanda; Suino-Powell, Kelly M.; Chalmers, Michael J.; Li, Jun; Yong, Eu-Leong; Zhu, Jian-Kang; Griffin, Patrick R.; Melcher, Karsten; Xu, H. Eric (Van Andel); (Scripps); (Purdue); (NU Singapore)

2014-10-02

Abscisic acid (ABA) is an essential hormone that controls plant growth, development, and responses to abiotic stresses. Central for ABA signaling is the ABA-mediated autoactivation of three monomeric Snf1-related kinases (SnRK2.2, -2.3, and -2.6). In the absence of ABA, SnRK2s are kept in an inactive state by forming physical complexes with type 2C protein phosphatases (PP2Cs). Upon relief of this inhibition, SnRK2 kinases can autoactivate through unknown mechanisms. Here, we report the crystal structures of full-length Arabidopsis thaliana SnRK2.3 and SnRK2.6 at 1.9- and 2.3-{angstrom} resolution, respectively. The structures, in combination with biochemical studies, reveal a two-step mechanism of intramolecular kinase activation that resembles the intermolecular activation of cyclin-dependent kinases. First, release of inhibition by PP2C allows the SnRK2s to become partially active because of an intramolecular stabilization of the catalytic domain by a conserved helix in the kinase regulatory domain. This stabilization enables SnRK2s to gain full activity by activation loop autophosphorylation. Autophosphorylation is more efficient in SnRK2.6, which has higher stability than SnRK2.3 and has well-structured activation loop phosphate acceptor sites that are positioned next to the catalytic site. Together, these data provide a structural framework that links ABA-mediated release of PP2C inhibition to activation of SnRK2 kinases.

Nuclear HER4 mediates acquired resistance to trastuzumab and is associated with poor outcome in HER2 positive breast cancer

Science.gov (United States)

Nafi, Siti Norasikin Mohd; Generali, Daniele; Kramer-Marek, Gabriela; Gijsen, Merel; Strina, Carla; Cappelletti, Mariarosa; Andreis, Daniele; Haider, Syed; Li, Ji-Liang; Bridges, Esther; Capala, Jacek; Ioannis, Roxanis; Harris, Adrian L; Kong, Anthony

2014-01-01

The role of HER4 in breast cancer is controversial and its role in relation to trastuzumab resistance remains unclear. We showed that trastuzumab treatment and its acquired resistance induced HER4 upregulation, cleavage and nuclear translocation. However, knockdown of HER4 by specific siRNAs increased trastuzumab sensitivity and reversed its resistance in HER2 positive breast cancer cells. Preventing HER4 cleavage by a γ-secretase inhibitor and inhibiting HER4 tyrosine kinase activity by neratinib decreased trastuzumab-induced HER4 nuclear translocation and enhanced trastuzumab response. There was also increased nuclear HER4 staining in the tumours from BT474 xenograft mice and human patients treated with trastuzumab. Furthermore, nuclear HER4 predicted poor clinical response to trastuzumab monotherapy in patients undergoing a window study and was shown to be an independent poor prognostic factor in HER2 positive breast cancer. Our data suggest that HER4 plays a key role in relation to trastuzumab resistance in HER2 positive breast cancer. Therefore, our study provides novel findings that HER4 activation, cleavage and nuclear translocation influence trastuzumab sensitivity and resistance in HER2 positive breast cancer. Nuclear HER4 could be a potential prognostic and predictive biomarker and understanding the role of HER4 may provide strategies to overcome trastuzumab resistance in HER2 positive breast cancer. PMID:25153719

Structural basis for basal activity and autoactivation of abscisic acid (ABA) signaling SnRK2 kinases

OpenAIRE

Ng, Ley-Moy; Soon, Fen-Fen; Zhou, X. Edward; West, Graham M.; Kovach, Amanda; Suino-Powell, Kelly M.; Chalmers, Michael J.; Li, Jun; Yong, Eu-Leong; Zhu, Jian-Kang; Griffin, Patrick R.; Melcher, Karsten; Xu, H. Eric

2011-01-01

Abscisic acid (ABA) is an essential hormone that controls plant growth, development, and responses to abiotic stresses. Central for ABA signaling is the ABA-mediated autoactivation of three monomeric Snf1-related kinases (SnRK2.2, -2.3, and -2.6). In the absence of ABA, SnRK2s are kept in an inactive state by forming physical complexes with type 2C protein phosphatases (PP2Cs). Upon relief of this inhibition, SnRK2 kinases can autoactivate through unknown mechanisms. Here, we report the cryst...

Structural changes in human cytomegalovirus cytoplasmic assembly sites in the absence of UL97 kinase activity

International Nuclear Information System (INIS)

Azzeh, Maysa; Honigman, Alik; Taraboulos, Albert; Rouvinski, Alexander; Wolf, Dana G.

2006-01-01

Studies of human cytomegalovirus (HCMV) UL97 kinase deletion mutant (ΔUL97) indicated a multi-step role for this kinase in early and late phases of the viral life cycle, namely, in DNA replication, capsid maturation and nuclear egress. Here, we addressed its possible involvement in cytoplasmic steps of HCMV assembly. Using the ΔUL97 and the UL97 kinase inhibitor NGIC-I, we demonstrate that the absence of UL97 kinase activity results in a modified subcellular distribution of the viral structural protein assembly sites, from compact structures impacting upon the nucleus to diffuse perinuclear structures punctuated by large vacuoles. Infection by either wild type or ΔUL97 viruses induced a profound reorganization of wheat germ agglutinin (WGA)-positive Golgi-related structures. Importantly, the viral-induced Golgi remodeling along with the reorganization of the nuclear architecture was substantially altered in the absence of UL97 kinase activity. These findings suggest that UL97 kinase activity might contribute to organization of the viral cytoplasmic assembly sites

Asymmetric expression of protein kinase CK2 subunits in human kidney tumors

DEFF Research Database (Denmark)

Stalter, G; Siemer, S; Becht, E

1994-01-01

of protein kinase CK2 alpha in tumors/normal tissue (T/N) was 1.58 and that of the protein kinase CK2 beta (T/N) was 2.65. The data suggest that the generally described increase in protein kinase CK2 activity in tumor cells may to some extent result from a deregulation in subunit biosynthesis or degradation...

Phosphorescence and delayed fluorescence properties of fluorone dyes in bio-related films

International Nuclear Information System (INIS)

Penzkofer, A.; Tyagi, A.; Slyusareva, E.; Sizykh, A.

2010-01-01

Graphical abstract: The spectral and temporal phosphorescence and delayed fluorescence behaviour of five fluorescein dyes in gelatine, starch, and chitosan is studied and basic parameters are determined. Research highlights: → Phosphorescence quantum yields of fluorone dyes in bio-related films are measured at room temperature. → Delayed fluorescence quantum yields of fluorone dyes in bio-related films are measured at room temperature. → Phosphorescence lifetimes of fluorone dyes in bio-related films are measured at room temperature. → Delayed fluorescence lifetimes of fluorone dyes in bio-related films are measured at room temperature. → General theory of short-pulse excited phosphorescence and delayed fluorescence is presented and relevant parameters are extracted. - Abstract: The phosphorescence and delayed fluorescence behaviour of the fluorone dyes disodium fluorescein (FL, uranine), 4,5-dibromofluorescein (DBF), eosin Y (EO), erythrosine B (ER), and rose bengal (RB) in bio-films of gelatine, starch, and chitosan at room temperature is studied. Phosphorescence and delayed fluorescence quantum yields and lifetimes were measured. The singlet-triplet dynamics is described and applied to the fluorone dyes for parameter extraction. For uranine films at room temperature no phosphorescence could be resolved. The efficiency of singlet-triplet intersystem crossing increased in the order φ ISC (DBF) ISC (EO) ISC (ER) ISC (RB) due to the heavy atom effect on spin-orbit coupling. The phosphorescence quantum yields increased in the order φ P (DBF) P (EO) P (RB) P (ER). The phosphorescence lifetimes followed the order τ P (DBF) > τ P (EO) > τ P (ER) > τ P (RB).

Stress-induced activation of protein kinase CK2 by direct interaction with p38 mitogen-activated protein kinase

DEFF Research Database (Denmark)

Sayed, M; Kim, S O; Salh, B S

2000-01-01

Protein kinase CK2 has been implicated in the regulation of a wide range of proteins that are important in cell proliferation and differentiation. Here we demonstrate that the stress signaling agents anisomycin, arsenite, and tumor necrosis factor-alpha stimulate the specific enzyme activity of CK2...... in the human cervical carcinoma HeLa cells by up to 8-fold, and this could be blocked by the p38 MAP kinase inhibitor SB203580. We show that p38alpha MAP kinase, in a phosphorylation-dependent manner, can directly interact with the alpha and beta subunits of CK2 to activate the holoenzyme through what appears...

Differential expression of poplar sucrose nonfermenting1-related protein kinase 2 genes in response to abiotic stress and abscisic acid.

Science.gov (United States)

Yu, Xiang; Takebayashi, Arika; Demura, Taku; Ohtani, Misato

2017-09-01

Knowledge on the responses of woody plants to abiotic stress can inform strategies to breed improved tree varieties and to manage tree species for environmental conservation and the production of lignocellulosic biomass. In this study, we examined the expression patterns of poplar (Populus trichocarpa) genes encoding members of the sucrose nonfermenting1-related protein kinase 2 (SnRK2) family, which are core components of the abiotic stress response. The P. trichocarpa genome contains twelve SnRK2 genes (PtSnRK2.1- PtSnRK2.12) that can be divided into three subclasses (I-III) based on the structures of their encoded kinase domains. We found that PtSnRK2s are differentially expressed in various organs. In MS medium-grown plants, all of the PtSnRK2 genes were significantly upregulated in response to abscisic acid (ABA) treatment, whereas osmotic and salt stress treatments induced only some (four and seven, respectively) of the PtSnRK2 genes. By contrast, soil-grown plants showed increased expression of most PtSnRK2 genes under drought and salt treatments, but not under ABA treatment. In soil-grown plants, drought stress induced SnRK2 subclass II genes in all tested organs (leaves, stems, and roots), whereas subclass III genes tended to be upregulated in leaves only. These results suggest that the PtSnRK2 genes are involved in abiotic stress responses, are at least partially activated by ABA, and show organ-specific responses.

The anti-apoptotic effect of IGF-1 on tissue resident stem cells is mediated via PI3-kinase dependent secreted frizzled related protein 2 (Sfrp2) release

International Nuclear Information System (INIS)

Gehmert, Sebastian; Sadat, Sanga; Song Yaohua; Yan Yasheng; Alt, Eckhard

2008-01-01

Previous studies suggest that IGF-1 may be used as an adjuvant to stem cell transfer in order to improve cell engraftment in ischemic tissue. In the current study, we investigated the effect of IGF-1 on serum deprivation and hypoxia induced stem cell apoptosis and the possible mechanisms involved. Exposure of adipose tissue derived stem cells (ASCs) to serum deprivation and hypoxia resulted in significant apoptosis in ASC which is partially prevented by IGF-1. IGF-1's anti-apoptotic effect was abolished in ASCs transfected with Sfrp2 siRNA but not by the control siRNA. Using Western blot analysis, we demonstrated that serum deprivation and hypoxia reduced the expression of nuclear β-catenin, which is reversed by IGF-1. IGF-1's effect on β-catenin expression was abolished by the presence of PI3-kinase inhibitor LY294002 or in ASCs transfected with Sfrp2 siRNA. These results suggest that IGF-1, through the release of the Sfrp2, contributes to cell survival by stabilizing β-catenin

Decree no 2007-1557 from November 2, 2007, relative to basic nuclear facilities and to the nuclear safety control of nuclear materials transport

International Nuclear Information System (INIS)

2007-11-01

This decree concerns the enforcement of articles 5, 17 and 36 of the law 2006-686 from June 13, 2006, relative to the transparency and safety in the nuclear domain. A consultative commission of basic nuclear facilities is established. The decree presents the general dispositions relative to basic nuclear facilities, the dispositions relative to their creation and operation, to their shutdown and dismantling. It precises the dispositions in the domain of public utility services, administrative procedures and sanctions. It stipulates also the particular dispositions relative to other facilities located in the vicinity of nuclear facilities, relative to the use of pressure systems, and relative to the transport of radioactive materials. (J.S.)

Induction of glutathione synthesis in human hepatocytes by acute and chronic arsenic exposure: Differential roles of mitogen-activated protein kinases

International Nuclear Information System (INIS)

Hou, Yongyong; Wang, Yi; Wang, Huihui; Xu, Yuanyuan

2014-01-01

Highlights: • Arsenic exposure increased intracellular levels of glutathione. • Mitogen-activated protein kinases were involved in glutathione homeostasis. • ERK contributed to glutathione synthesis during acute arsenic exposure. • Glutathione synthesis was regulated by p38 at least in part independent of NRF2 during chronic arsenic exposure. - Abstract: Glutathione (GSH) is a vital component of antioxidant defense which protects cells from toxic insults. Previously we found intracellular GSH was involved in cell resistance against arsenic-induced cytotoxicity. However, molecular mechanisms of GSH homeostasis during arsenic exposure are largely undefined. Here, we investigated roles of mitogen-activated protein kinases (MAPKs) in GSH synthesis pathway with two arsenic exposure strategies by using Chang human hepatocytes. In one strategy, acute arsenic exposure (20 μM, 24 h) was applied, as MAPK signaling is generally considered to be transient. In the other one, chronic arsenic exposure (500 nM, 20 weeks) was applied, which mimicked the general human exposure to arsenic. We found that acute arsenic exposure activated extracellular signal-regulated 1/2 kinases (ERK1/2) and c-Jun N-terminal kinase (JNK) in parallel with increased transcription and nuclear translocation of factor-erythroid 2-related factor 2 (NRF2) and enhanced expression of γ-glutamyl cysteine ligase catalytic subunit (GCLC), resulting in elevated intracellular GSH levels. Specific ERK inhibitor abolished arsenic-induced NRF2 nuclear translocation and GSH synthesis. During chronic arsenic exposure which induced a malignant cellular phenotype, continuous p38 activation and NRF2 nuclear translocation were observed with enhanced GSH synthesis. Specific p38 inhibitor attenuated arsenic-enhanced GSH synthesis without changing NRF2 nuclear translocation. Taken together, our results indicate MAPK pathways play an important role in cellular GSH homeostasis in response to arsenic. However, the

Posttranslational Modifications of Pyruvate Kinase M2: Tweaks that Benefit Cancer

Directory of Open Access Journals (Sweden)

Gopinath Prakasam

2018-02-01

Full Text Available Cancer cells rewire metabolism to meet biosynthetic and energetic demands. The characteristic increase in glycolysis, i.e., Warburg effect, now considered as a hallmark, supports cancer in various ways. To attain such metabolic reshuffle, cancer cells preferentially re-express the M2 isoform of pyruvate kinase (PKM2, M2-PK and alter its quaternary structure to generate less-active PKM2 dimers. The relatively inactive dimers cause the accumulation of glycolytic intermediates that are redirected into anabolic pathways. In addition, dimeric PKM2 also benefits cancer cells through various non-glycolytic moonlight functions, such as gene transcription, protein kinase activity, and redox balance. A large body of data have shown that several distinct posttranslation modifications (PTMs regulate PKM2 in a way that benefits cancer growth, e.g., formation of PKM2 dimers. This review discusses the recent advancements in our understanding of various PTMs and the benefits they impart to the sustenance of cancer. Understanding the PTMs in PKM2 is crucial to assess their therapeutic potential and to design novel anticancer strategies.

Tyr721 regulates specific binding of the CSF-1 receptor kinase insert to PI 3'-kinase SH2 domains: a model for SH2-mediated receptor-target interactions.

Science.gov (United States)

Reedijk, M; Liu, X; van der Geer, P; Letwin, K; Waterfield, M D; Hunter, T; Pawson, T

1992-01-01

Efficient binding of active phosphatidylinositol (PI) 3'-kinase to the autophosphorylated macrophage colony stimulating factor receptor (CSF-1R) requires the noncatalytic kinase insert (KI) region of the receptor. To test whether this region could function independently to bind PI 3'-kinase, the isolated CSF-1R KI was expressed in Escherichia coli, and was inducibly phosphorylated on tyrosine. The tyrosine phosphorylated form of the CSF-1R KI bound PI 3'-kinase in vitro, whereas the unphosphorylated form had no binding activity. The p85 alpha subunit of PI 3'-kinase contains two Src homology (SH)2 domains, which are implicated in the interactions of signalling proteins with activated receptors. Bacterially expressed p85 alpha SH2 domains complexed in vitro with the tyrosine phosphorylated CSF-1R KI. Binding of the CSF-1R KI to PI 3'-kinase activity, and to the p85 alpha SH2 domains, required phosphorylation of Tyr721 within the KI domain, but was independent of phosphorylation at Tyr697 and Tyr706. Tyr721 was also critical for the association of activated CSF-1R with PI 3'-kinase in mammalian cells. Complex formation between the CSF-1R and PI 3'-kinase can therefore be reconstructed in vitro in a specific interaction involving the phosphorylated receptor KI and the SH2 domains of p85 alpha. Images PMID:1314163

Casein kinase-2 structure-function relationship

DEFF Research Database (Denmark)

Boldyreff, B; Meggio, F; Pinna, L A

1992-01-01

Nine mutants of human casein kinase-2 beta subunit have been created and assayed for their ability to assemble with the catalytic alpha subunit to give, at a 1:1 molar ratio, a fully competent CK-2 holoenzyme as judged by the following criteria: 1) the generation of an active heterotetrameric form...

The GCKIII Kinase Sps1 and the 14-3-3 Isoforms, Bmh1 and Bmh2, Cooperate to Ensure Proper Sporulation in Saccharomyces cerevisiae

Science.gov (United States)

Slubowski, Christian J.; Paulissen, Scott M.; Huang, Linda S.

2014-01-01

Sporulation in the budding yeast Saccharomyces cerevisiae is a developmental program initiated in response to nutritional deprivation. Sps1, a serine/threonine kinase, is required for sporulation, but relatively little is known about the molecular mechanisms through which it regulates this process. Here we show that SPS1 encodes a bona-fide member of the GCKIII subfamily of STE20 kinases, both through phylogenetic analysis of the kinase domain and examination of its C-terminal regulatory domain. Within the regulatory domain, we find Sps1 contains an invariant ExxxPG region conserved from plant to human GCKIIIs that we call the EPG motif; we show this EPG motif is important for SPS1 function. We also find that Sps1 is phosphorylated near its N-terminus on Threonine 12, and that this phosphorylation is required for the efficient production of spores. In Sps1, Threonine 12 lies within a 14-3-3 consensus binding sequence, and we show that the S. cerevisiae 14-3-3 proteins Bmh1 and Bmh2 bind Sps1 in a Threonine 12-dependent fashion. This interaction is significant, as BMH1 and BMH2 are required during sporulation and genetically interact with SPS1 in sporulating cells. Finally, we observe that Sps1, Bmh1 and Bmh2 are present in both the nucleus and cytoplasm during sporulation. We identify a nuclear localization sequence in Sps1 at amino acids 411–415, and show that this sequence is necessary and sufficient for nuclear localization. Taken together, these data identify regions within Sps1 critical for its function and indicate that SPS1 and 14-3-3s act together to promote proper sporulation in S. cerevisiae. PMID:25409301

Src-family-tyrosine kinase Lyn is critical for TLR2-mediated NF-κB activation through the PI 3-kinase signaling pathway.

Science.gov (United States)

Toubiana, Julie; Rossi, Anne-Lise; Belaidouni, Nadia; Grimaldi, David; Pene, Frederic; Chafey, Philippe; Comba, Béatrice; Camoin, Luc; Bismuth, Georges; Claessens, Yann-Erick; Mira, Jean-Paul; Chiche, Jean-Daniel

2015-10-01

TLR2 has a prominent role in host defense against a wide variety of pathogens. Stimulation of TLR2 triggers MyD88-dependent signaling to induce NF-κB translocation, and activates a Rac1-PI 3-kinase dependent pathway that leads to transactivation of NF-κB through phosphorylation of the P65 NF-κB subunit. This transactivation pathway involves tyrosine phosphorylations. The role of the tyrosine kinases in TLR signaling is controversial, with discrepancies between studies using only chemical inhibitors and knockout mice. Here, we show the involvement of the tyrosine-kinase Lyn in TLR2-dependent activation of NF-κB in human cellular models, by using complementary inhibition strategies. Stimulation of TLR2 induces the formation of an activation cluster involving TLR2, CD14, PI 3-kinase and Lyn, and leads to the activation of AKT. Lyn-dependent phosphorylation of the p110 catalytic subunit of PI 3-kinase is essential to the control of PI 3-kinase biological activity upstream of AKT and thereby to the transactivation of NF-κB. Thus, Lyn kinase activity is crucial in TLR2-mediated activation of the innate immune response in human mononuclear cells. © The Author(s) 2015.

RhoA/Rho Kinase Mediates Neuronal Death Through Regulating cPLA2 Activation.

Science.gov (United States)

Wu, Xiangbing; Walker, Chandler L; Lu, Qingbo; Wu, Wei; Eddelman, Daniel B; Parish, Jonathan M; Xu, Xiao-Ming

2017-11-01

Activation of RhoA/Rho kinase leads to growth cone collapse and neurite retraction. Although RhoA/Rho kinase inhibition has been shown to improve axon regeneration, remyelination and functional recovery, its role in neuronal cell death remains unclear. To determine whether RhoA/Rho kinase played a role in neuronal death after injury, we investigated the relationship between RhoA/Rho kinase and cytosolic phospholipase A 2 (cPLA 2 ), a lipase that mediates inflammation and cell death, using an in vitro neuronal death model and an in vivo contusive spinal cord injury model performed at the 10th thoracic (T10) vertebral level. We found that co-administration of TNF-α and glutamate induced spinal neuron death, and activation of RhoA, Rho kinase and cPLA 2 . Inhibition of RhoA, Rho kinase and cPLA 2 significantly reduced TNF-α/glutamate-induced cell death by 33, 52 and 43 %, respectively (p < 0.001). Inhibition of RhoA and Rho kinase also significantly downregulated cPLA 2 activation by 66 and 60 %, respectively (p < 0.01). Furthermore, inhibition of RhoA and Rho kinase reduced the release of arachidonic acid, a downstream substrate of cPLA 2 . The immunofluorescence staining showed that ROCK 1 or ROCK 2 , two isoforms of Rho kinase, was co-localized with cPLA 2 in neuronal cytoplasm. Interestingly, co-immunoprecipitation (Co-IP) assay showed that ROCK 1 or ROCK 2 bonded directly with cPLA 2 and phospho-cPLA 2 . When the Rho kinase inhibitor Y27632 was applied in mice with T10 contusion injury, it significantly decreased cPLA 2 activation and expression and reduced injury-induced apoptosis at and close to the lesion site. Taken together, our results reveal a novel mechanism of RhoA/Rho kinase-mediated neuronal death through regulating cPLA 2 activation.

Berberine activates Nrf2 nuclear translocation and inhibits apoptosis induced by high glucose in renal tubular epithelial cells through a phosphatidylinositol 3-kinase/Akt-dependent mechanism.

Science.gov (United States)

Zhang, Xiuli; Liang, Dan; Lian, Xu; Jiang, Yan; He, Hui; Liang, Wei; Zhao, Yue; Chi, Zhi-Hong

2016-06-01

Apoptosis of tubular epithelial cells is a major feature of diabetic kidney disease, and hyperglycemia triggers the generation of free radicals and oxidant stress in tubular cells. Berberine (BBR) is identified as a potential anti-diabetic herbal medicine due to its beneficial effects on insulin sensitivity, glucose metabolism and glycolysis. In this study, the underlying mechanisms involved in the protective effects of BBR on high glucose-induced apoptosis were explored using cultured renal tubular epithelial cells (NRK-52E cells) and human kidney proximal tubular cell line (HK-2 cells). We identified the pivotal role of phosphatidylinositol 3-kinase (PI3K)/Akt in BBR cellular defense mechanisms and revealed the novel effect of BBR on nuclear factor (erythroid-derived 2)-related factor-2 (Nrf2) and heme oxygenase (HO)-1 in NRK-52E and HK-2 cells. BBR attenuated reactive oxygen species production, antioxidant defense (GSH and SOD) and oxidant-sensitive proteins (Nrf2 and HO-1), which also were blocked by LY294002 (an inhibitor of PI3K) in HG-treated NRK-52E and HK-2 cells. Furthermore, BBR improved mitochondrial function by increasing mitochondrial membrane potential. BBR-induced anti-apoptotic function was demonstrated by decreasing apoptotic proteins (cytochrome c, Bax, caspase3 and caspase9). All these findings suggest that BBR exerts the anti-apoptosis effects through activation of PI3K/Akt signal pathways and leads to activation of Nrf2 and induction of Nrf2 target genes, and consequently protecting the renal tubular epithelial cells from HG-induced apoptosis.

SH2 dependent autophosphorylation within the Tec family kinase Itk

Science.gov (United States)

Joseph, Raji E.; Severin, Andrew; Min, Lie; Fulton, D. Bruce; Andreotti, Amy H.

2009-01-01

The Tec family kinase, Itk, undergoes an in cis autophosphorylation on Y180 within its SH3 domain. Autophosphorylation of the Itk SH3 domain by the Itk kinase domain is strictly dependent on the presence of the intervening SH2 domain. A direct docking interaction between the Itk kinase and SH2 domains brings the Itk SH3 domain into the active site where Y180 is then phosphorylated. We now identify the residues on the surface of the Itk SH2 domain responsible for substrate docking and show that this SH2 surface mediates autophosphorylation in the full length Itk molecule. The canonical phospholigand binding site on the SH2 domain is not involved in substrate docking, instead the docking site consists of side chains from three loop regions (AB, EF and BG) and part of the βD strand. These results are extended into Btk, a Tec family kinase linked to the B cell deficiency X-linked agammaglobulinemia (XLA). Our results suggest that some XLA causing mutations might impair Btk phosphorylation. PMID:19523959

Uncaria rhynchophylla inhibits the production of nitric oxide and interleukin-1β through blocking nuclear factor κB, Akt, and mitogen-activated protein kinase activation in macrophages.

Science.gov (United States)

Kim, Ji-Hee; Bae, Chang Hwan; Park, Sun Young; Lee, Sang Joon; Kim, YoungHee

2010-10-01

The stems with hook of Uncaria rhynchophylla have been used in traditional medicine as an antipyretic, antihypertensive, and anticonvulsant in China and Korea. In this study, we investigated the mechanism responsible for anti-inflammatory effects of U. rhynchophylla in RAW 264.7 macrophages. The aqueous extract of U. rhynchophylla inhibited lipopolysaccharide (LPS)-induced nitric oxide (NO) and interleukin (IL)-1β secretion as well as inducible NO synthase (iNOS) expression, without affecting cell viability. Furthermore, U. rhynchophylla suppressed LPS-induced nuclear factor κB (NF-κB) activation, phosphorylation, and degradation of inhibitory protein IκB (IκB)-α, phosphorylation of Akt, extracellular signal-regulated kinase 1/2, p38 kinase, and c-Jun N-terminal kinase. These results suggest that U. rhynchophylla has the inhibitory effects on LPS-induced NO and IL-1β production in macrophages through blockade in the phosphorylation of Akt and mitogen-activated protein kinases, following IκB-α degradation and NF-κB activation.

Damage-induced DNA replication stalling relies on MAPK-activated protein kinase 2 activity

DEFF Research Database (Denmark)

Köpper, Frederik; Bierwirth, Cathrin; Schön, Margarete

2013-01-01

knockdown of the MAP kinase-activated protein kinase 2 (MK2), a kinase currently implicated in p38 stress signaling and G2 arrest. Depletion or inhibition of MK2 also protected cells from DNA damage-induced cell death, and mice deficient for MK2 displayed decreased apoptosis in the skin upon UV irradiation...

Nuclear Overhauser effect studies on the conformation of magnesium adenosine 5'-triphosphate bound to rabbit muscle creatine kinase

International Nuclear Information System (INIS)

Rosevear, P.R.; Powers, V.M.; Dowhan, D.; Mildvan, A.S.; Kenyon, G.L.

1987-01-01

Nuclear Overhauser effects were used to determine interproton distances on MgATP bound to rabbit muscle creatine kinase. The internuclear distances were used in a distance geometry program that objectively determines both the conformation of the bound MgATP and its uniqueness. Two classes of structures were found that satisfied the measured interproton distances. Both classes had the same anti glycosidic torsional angle (X = 78 +/- 10 0 ) but differed in their ribose ring puckers (O1'-endo or C4'-exo). The uniqueness of the glycosidic torsional angle is consistent with the preference of creatine kinase for adenine nucleotides. One of these conformations of MgATP bound to creatine kinase is indistinguishable from the conformation found for Co(NH 3 ) 4 ATP bound to the catalytic subunit of protein kinase, which also has a high specificity for adenine nucleotides. Distance geometry calculations also suggest that upper limit distances, when low enough (≤ 3.4 A), can be used instead of measured distances to define, within experimental error, the glycosidic torsional angle of bound nucleotides. However, this approach does not permit an evaluation of the ribose ring pucker

Protein kinase C mediates platelet secretion and thrombus formation through protein kinase D2.

Science.gov (United States)

Konopatskaya, Olga; Matthews, Sharon A; Harper, Matthew T; Gilio, Karen; Cosemans, Judith M E M; Williams, Christopher M; Navarro, Maria N; Carter, Deborah A; Heemskerk, Johan W M; Leitges, Michael; Cantrell, Doreen; Poole, Alastair W

2011-07-14

Platelets are highly specialized blood cells critically involved in hemostasis and thrombosis. Members of the protein kinase C (PKC) family have established roles in regulating platelet function and thrombosis, but the molecular mechanisms are not clearly understood. In particular, the conventional PKC isoform, PKCα, is a major regulator of platelet granule secretion, but the molecular pathway from PKCα to secretion is not defined. Protein kinase D (PKD) is a family of 3 kinases activated by PKC, which may represent a step in the PKC signaling pathway to secretion. In the present study, we show that PKD2 is the sole PKD member regulated downstream of PKC in platelets, and that the conventional, but not novel, PKC isoforms provide the upstream signal. Platelets from a gene knock-in mouse in which 2 key phosphorylation sites in PKD2 have been mutated (Ser707Ala/Ser711Ala) show a significant reduction in agonist-induced dense granule secretion, but not in α-granule secretion. This deficiency in dense granule release was responsible for a reduced platelet aggregation and a marked reduction in thrombus formation. Our results show that in the molecular pathway to secretion, PKD2 is a key component of the PKC-mediated pathway to platelet activation and thrombus formation through its selective regulation of dense granule secretion.

Constitutive Activity in an Ancestral Form of Abl Tyrosine Kinase.

Directory of Open Access Journals (Sweden)

Saadat U Aleem

Full Text Available The c-abl proto-oncogene encodes a nonreceptor tyrosine kinase that is found in all metazoans, and is ubiquitously expressed in mammalian tissues. The Abl tyrosine kinase plays important roles in the regulation of mammalian cell physiology. Abl-like kinases have been identified in the genomes of unicellular choanoflagellates, the closest relatives to the Metazoa, and in related unicellular organisms. Here, we have carried out the first characterization of a premetazoan Abl kinase, MbAbl2, from the choanoflagellate Monosiga brevicollis. The enzyme possesses SH3, SH2, and kinase domains in a similar arrangement to its mammalian counterparts, and is an active tyrosine kinase. MbAbl2 lacks the N-terminal myristoylation and cap sequences that are critical regulators of mammalian Abl kinase activity, and we show that MbAbl2 is constitutively active. When expressed in mammalian cells, MbAbl2 strongly phosphorylates cellular proteins on tyrosine, and transforms cells much more potently than mammalian Abl kinase. Thus, MbAbl2 appears to lack the autoinhibitory mechanism that tightly constrains the activity of mammalian Abl kinases, suggesting that this regulatory apparatus arose more recently in metazoan evolution.

Programmed cell death 4 protein (Pdcd4) and homeodomain-interacting protein kinase 2 (Hipk2) antagonistically control translation of Hipk2 mRNA.

Science.gov (United States)

Ohnheiser, Johanna; Ferlemann, Eva; Haas, Astrid; Müller, Jan P; Werwein, Eugen; Fehler, Olesja; Biyanee, Abhiruchi; Klempnauer, Karl-Heinz

2015-07-01

The tumor suppressor protein programmed cell death 4 (Pdcd4) is a highly conserved RNA-binding protein that inhibits the translation of specific mRNAs. Here, we have identified the homeobox-interacting protein kinase-2 (Hipk2) mRNA as a novel translational target of Pdcd4. Unlike most other protein kinases Hipk2 is constitutively active after being synthesized by the ribosome and its expression and activity are thought to be mainly controlled by modulation of the half-life of the kinase. Our work provides the first evidence that Hipk2 expression is also controlled on the level of translation. We show that Hipk2 stimulates the translation of its own mRNA and that Pdcd4 suppresses the translation of Hipk2 mRNA by interfering with this auto-regulatory feedback mechanism. We also show that the translation of the related kinase Hipk1 is controlled by a similar feedback loop and that Hipk2 also stimulates the translation of Hipk1 mRNA. Taken together, our work describes a novel mechanism of translational suppression by Pdcd4 and shows for the first time that Hipk2 controls its own synthesis by an auto-regulatory feedback mechanism. Furthermore, the effect of Hipk2 on the translation of Hipk1 RNA suggests that Hipk2 and Pdcd4 can act in similar manner to control the translation of other mRNAs. Copyright © 2015 Elsevier B.V. All rights reserved.

FY1990 Nuclear-related budget demand totals 398 billion yen, up 2.7%

International Nuclear Information System (INIS)

Anon.

1989-01-01

Funds needed to promote the development and utilization of nuclear energy in fiscal 1990 in a planned and integrated way total yen398,427 million on a cash basis, up 2.7% over fiscal 1989. The Science and Technology Agency, which has two major nuclear RandD organizations -- the Japan Atomic Energy Research Institute and the Power Reactor and Nuclear Fuel Development Corp. -- within its jurisdiction, has asked for a total of yen297,765 million (up 5.7%), about three-fourths of the total nuclear-related budget demand. The budget demand of the Ministry of International Trade and Industry aggregates yen96.375 million, down 5.1%. The budget demand of the Ministry of Foreign Affairs is yen2,962 million, including subscriptions and contributions to IAEA, and that of the Ministry of Transport, yen42 million, including research and analysis costs for setting safety standards for the transportation of radioactive materials. The budget demand of the Ministry of Agriculture, Forestry and Fisheries is yen167 million, including costs for the prevention and elimination of melon-flies in the Amami Islands, and for the Tsukuba Agriculture and Forestry Research Exchange Center. (N.K.)

Resource Letter MP-2: The Manhattan project and related nuclear research

Science.gov (United States)

Reed, B. Cameron

2011-02-01

This Resource Letter is a supplement to my earlier Resource Letter MP-1 and provides further sources on the Manhattan Project and related nuclear research. Books and journal articles are cited for the following topics: General works, technical works, biographical and autobiographical works, foreign wartime programs and allied intelligence, technical papers of historical interest, and postwar policy and technical developments. I also give a list of videos and websites dealing with the Manhattan Project, nuclear weapons, and nuclear issues.

Band 3 tyrosine kinase in avian erythrocyte plasma membrane is immunologically related to pp60c-src

International Nuclear Information System (INIS)

Hillsgrove, D.; Shores, C.G.; Parker, J.C.; Maness, P.F.

1987-01-01

The authors have identified in the plasma membrane of the chicken erythrocyte a 60-kDa tyrosine-specific protein kinase immunologically related to the transforming protein pp60 v-src of Rous sarcoma virus. The erythrocyte protein kinase phosphorylated heavy chains of tumor-bearing rabbit (TBR) antibodies reactive with pp60 c-src at tyrosine in immune complex protein kinase assays. The kinase was identified as a 60-kDa protein by [ 35 S]methionine labeling of erythrocytes and by autophosphorylation in immune complexes. The kinase migrated on two-dimensional gel electrophoresis with an apparent pI and molecular mass similar to pp60 c-src . A plasma membrane-enriched fraction isolated from chicken red cells contained the majority of the kinase activity. Incubation of the plasma membrane fraction with [ 32 P]ATP resulted in tyrosine phosphorylation of the anion transport protein band 3. Band 3 phosphorylation was blocked by TBR antibodies, indicting that the kinase recognized by pp60 c-src antibodies was responsible for band 3 phosphorylation. These results demonstrate that the avian erythrocyte plasma membrane contains a tightly bound tyrosine-specific protein kinase identical or closely related to pp60 c-src and that this kinase is responsible for band 3 phosphorylation in vitro

Theobromine, the primary methylxanthine found in Theobroma cacao, prevents malignant glioblastoma proliferation by negatively regulating phosphodiesterase-4, extracellular signal-regulated kinase, Akt/mammalian target of rapamycin kinase, and nuclear factor-kappa B.

Science.gov (United States)

Sugimoto, Naotoshi; Miwa, Shinji; Hitomi, Yoshiaki; Nakamura, Hiroyuki; Tsuchiya, Hiroyuki; Yachie, Akihiro

2014-01-01

Theobromine, a caffeine derivative, is the primary methylxanthine produced by Theobroma cacao. We previously showed that methylxanthines, including caffeine and theophylline, have antitumor and antiinflammatory effects, which are in part mediated by their inhibition of phosphodiesterase (PDE). A member of the PDE family, PDE4, is widely expressed in and promotes the growth of glioblastoma, the most common type of brain tumor. The purpose of this study was to determine whether theobromine could exert growth inhibitory effects on U87-MG, a cell line derived from human malignant glioma. We show that theobromine treatment elevates intracellular cAMP levels and increases the activity of p38 mitogen-activated protein kinase and c-Jun N-terminal kinase, whereas it attenuates p44/42 extracellular signal-regulated kinase activity and the Akt/mammalian target of rapamycin kinase and nuclear factor-kappa B signal pathways. It also inhibits cell proliferation. These results suggest that foods and beverages containing cocoa bean extracts, including theobromine, might be extremely effective in preventing human glioblastoma.

5´AMP activated protein kinase α2 controls substrate metabolism during post-exercise recovery via regulation of pyruvate dehydrogenase kinase 4

DEFF Research Database (Denmark)

Fritzen, Andreas Mæchel; Lundsgaard, Annemarie; Jeppesen, Jacob

2015-01-01

after prolonged exercise and during the following six hours post exercise in 5´AMP activated protein kinase (AMPK)α2 and α1 knock-out (KO) and wild type (WT) mice with free access to food. Substrate oxidation was similar during exercise at the same relative intensity between genotypes. During post...

MAP kinase-signaling controls nuclear translocation of tripeptidyl-peptidase II in response to DNA damage and oxidative stress

Energy Technology Data Exchange (ETDEWEB)

Preta, Giulio; Klark, Rainier de; Chakraborti, Shankhamala [Center for Molecular Medicine (CMM), Department of Medicine, Karolinska Institutet, Karolinska University Hospital, 171 76 Stockholm (Sweden); Glas, Rickard, E-mail: rickard.glas@ki.se [Center for Molecular Medicine (CMM), Department of Medicine, Karolinska Institutet, Karolinska University Hospital, 171 76 Stockholm (Sweden)

2010-08-27

Research highlights: {yields} Nuclear translocation of TPPII occurs in response to different DNA damage inducers. {yields} Nuclear accumulation of TPPII is linked to ROS and anti-oxidant enzyme levels. {yields} MAPKs control nuclear accumulation of TPPII. {yields} Inhibited nuclear accumulation of TPPII decreases DNA damage-induced {gamma}-H2AX expression. -- Abstract: Reactive oxygen species (ROS) are a continuous hazard in eukaroytic cells by their ability to cause damage to biomolecules, in particular to DNA. Previous data indicated that the cytosolic serine peptidase tripeptidyl-peptidase II (TPPII) translocates into the nucleus of most tumor cell lines in response to {gamma}-irradiation and ROS production; an event that promoted p53 expression as well as caspase-activation. We here observed that nuclear translocation of TPPII was dependent on signaling by MAP kinases, including p38MAPK. Further, this was caused by several types of DNA-damaging drugs, a DNA cross-linker (cisplatinum), an inhibitor of topoisomerase II (etoposide), and to some extent also by nucleoside-analogues (5-fluorouracil, hydroxyurea). In the minority of tumor cell lines where TPPII was not translocated into the nucleus in response to DNA damage we observed reduced intracellular ROS levels, and the expression levels of redox defense systems were increased. Further, treatment with the ROS-inducer {gamma}-hexa-chloro-cyclohexane ({gamma}-HCH, lindane), an inhibitor of GAP junctions, restored nuclear translocation of TPPII in these cell lines upon {gamma}-irradiation. Moreover, blocking nuclear translocation of TPPII in etoposide-treated cells, by using a peptide-derived inhibitor (Z-Gly-Leu-Ala-OH), attenuated expression of {gamma}-H2AX in {gamma}-irradiated melanoma cells. Our results indicated a role for TPPII in MAPK-dependent DNA damage signaling.

Transgene expression of Drosophila melanogaster nucleoside kinase reverses mitochondrial thymidine kinase 2 deficiency.

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Krishnan, Shuba; Zhou, Xiaoshan; Paredes, João A; Kuiper, Raoul V; Curbo, Sophie; Karlsson, Anna

2013-02-15

A strategy to reverse the symptoms of thymidine kinase 2 (TK2) deficiency in a mouse model was investigated. The nucleoside kinase from Drosophila melanogaster (Dm-dNK) was expressed in TK2-deficient mice that have been shown to present with a severe phenotype caused by mitochondrial DNA depletion. The Dm-dNK(+/-) transgenic mice were shown to be able to rescue the TK2-deficient mice. The Dm-dNK(+/-)TK2(-/-) mice were normal as judged by growth and behavior during the observation time of 6 months. The Dm-dNK-expressing mice showed a substantial increase in thymidine-phosphorylating activity in investigated tissues. The Dm-dNK expression also resulted in highly elevated dTTP pools. The dTTP pool alterations did not cause specific mitochondrial DNA mutations or deletions when 6-month-old mice were analyzed. The mitochondrial DNA was also detected at normal levels. In conclusion, the Dm-dNK(+/-)TK2(-/-) mouse model illustrates how dTMP synthesized in the cell nucleus can compensate for loss of intramitochondrial dTMP synthesis in differentiated tissue. The data presented open new possibilities to treat the severe symptoms of TK2 deficiency.

Regulation of protein kinase C-related kinase (PRK) signalling by the TPα and TPβ isoforms of the human thromboxane A2 receptor: Implications for thromboxane- and androgen- dependent neoplastic and epigenetic responses in prostate cancer.

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O'Sullivan, Aine G; Mulvaney, Eamon P; Kinsella, B Therese

2017-04-01

The prostanoid thromboxane (TX) A 2 and its T Prostanoid receptor (the TP) are increasingly implicated in prostate cancer (PCa). Mechanistically, we recently discovered that both TPα and TPβ form functional signalling complexes with members of the protein kinase C-related kinase (PRK) family, AGC- kinases essential for the epigenetic regulation of androgen receptor (AR)-dependent transcription and promising therapeutic targets for treatment of castrate-resistant prostate cancer (CRPC). Critically, similar to androgens, activation of the PRKs through the TXA 2 /TP signalling axis induces phosphorylation of histone H3 at Thr11 (H3Thr11), a marker of androgen-induced chromatin remodelling and transcriptional activation, raising the possibility that TXA 2 -TP signalling can mimic and/or enhance AR-induced cellular changes even in the absence of circulating androgens such as in CRPC. Hence the aim of the current study was to investigate whether TXA 2 /TP-induced PRK activation can mimic and/or enhance AR-mediated cellular responses in the model androgen-responsive prostate adenocarcinoma LNCaP cell line. We reveal that TXA 2 /TP signalling can act as a neoplastic- and epigenetic-regulator, promoting and enhancing both AR-associated chromatin remodelling (H3Thr11 phosphorylation, WDR5 recruitment and acetylation of histone H4 at lysine 16) and AR-mediated transcriptional activation (e.g of the KLK3/prostate-specific antigen and TMPRSS2 genes) through mechanisms involving TPα/TPβ mediated-PRK1 and PRK2, but not PRK3, signalling complexes. Overall, these data demonstrate that TPα/TPβ can act as neoplastic and epigenetic regulators by mimicking and/or enhancing the actions of androgens within the prostate and provides further mechanistic insights into the role of the TXA 2 /TP signalling axis in PCa, including potentially in CRPC. Copyright © 2017 Elsevier B.V. All rights reserved.

DMPD: Are the IKKs and IKK-related kinases TBK1 and IKK-epsilon similarly activated? [Dynamic Macrophage Pathway CSML Database

Lifescience Database Archive (English)

Full Text Available 18353649 Are the IKKs and IKK-related kinases TBK1 and IKK-epsilon similarly activa...e IKKs and IKK-related kinases TBK1 and IKK-epsilon similarly activated? PubmedID... 18353649 Title Are the IKKs and IKK-related kinases TBK1 and IKK-epsilon similarly activated? Authors Chau

LRRK2 kinase activity is dependent on LRRK2 GTP binding capacity but independent of LRRK2 GTP binding.

Directory of Open Access Journals (Sweden)

Jean-Marc Taymans

Full Text Available Leucine rich repeat kinase 2 (LRRK2 is a Parkinson's disease (PD gene that encodes a large multidomain protein including both a GTPase and a kinase domain. GTPases often regulate kinases within signal transduction cascades, where GTPases act as molecular switches cycling between a GTP bound "on" state and a GDP bound "off" state. It has been proposed that LRRK2 kinase activity may be increased upon GTP binding at the LRRK2 Ras of complex proteins (ROC GTPase domain. Here we extensively test this hypothesis by measuring LRRK2 phosphorylation activity under influence of GDP, GTP or non-hydrolyzable GTP analogues GTPγS or GMPPCP. We show that autophosphorylation and lrrktide phosphorylation activity of recombinant LRRK2 protein is unaltered by guanine nucleotides, when co-incubated with LRRK2 during phosphorylation reactions. Also phosphorylation activity of LRRK2 is unchanged when the LRRK2 guanine nucleotide binding pocket is previously saturated with various nucleotides, in contrast to the greatly reduced activity measured for the guanine nucleotide binding site mutant T1348N. Interestingly, when nucleotides were incubated with cell lysates prior to purification of LRRK2, kinase activity was slightly enhanced by GTPγS or GMPPCP compared to GDP, pointing to an upstream guanine nucleotide binding protein that may activate LRRK2 in a GTP-dependent manner. Using metabolic labeling, we also found that cellular phosphorylation of LRRK2 was not significantly modulated by nucleotides, although labeling is significantly reduced by guanine nucleotide binding site mutants. We conclude that while kinase activity of LRRK2 requires an intact ROC-GTPase domain, it is independent of GDP or GTP binding to ROC.

Zn2+, not Ca2+, is the most effective cation for activation of dolichol kinase of mammalian brain.

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Sakakihara, Y; Volpe, J J

1985-12-15

The cation specificity of dolichol kinase of mammalian brain and the potential involvement of a Ca2+-calmodulin system in regulation of this enzyme have been studied. Among 10 divalent cations examined, Zn2+ was found to be most effective for the activation of dolichol kinase of rat and calf brain and cultured C-6 glial cells. The activations with Ca2+, Co2+, and Mg2+ were 53%, 32%, and 18% of the full activation with Zn2+, respectively. No combinations of the cations could activate the enzyme as much as Zn2+ alone. A role for a Ca2+-calmodulin system in the regulation of brain dolichol kinase was not supported by our data. First, the concentration of free Ca2+ required for the maximum activation of dolichol kinase was two to three orders of magnitude greater than the concentration required by typical calmodulin-dependent enzymes. Second, neither the depletion of calmodulin from the microsomal fraction nor the addition of exogenous calmodulin caused an alteration in the activation of dolichol kinase by Ca2+ (or Zn2+). Third, antagonists of calmodulin failed to suppress the activation of the enzyme by Ca2+ (or Zn2+). The data raise the possibility that Zn2+ is involved in the regulation of dolichol kinase in brain.

Rho-kinase signaling controls nucleocytoplasmic shuttling of class IIa Histone Deacetylase (HDAC7) and transcriptional activation of orphan nuclear receptor NR4A1

Energy Technology Data Exchange (ETDEWEB)

Compagnucci, Claudia; Barresi, Sabina [Unit of Molecular Medicine for Neuromuscular and Neurodegenerative Disorders, Department of Neurosciences, Bambino Gesù Children’s Hospital, IRCCS, Rome (Italy); Petrini, Stefania [Research Laboratories, Confocal Microscopy Core Facility, Bambino Gesù Children’s Hospital, IRCCS, Rome (Italy); Bertini, Enrico [Unit of Molecular Medicine for Neuromuscular and Neurodegenerative Disorders, Department of Neurosciences, Bambino Gesù Children’s Hospital, IRCCS, Rome (Italy); Zanni, Ginevra, E-mail: ginevra.zanni@opbg.net [Unit of Molecular Medicine for Neuromuscular and Neurodegenerative Disorders, Department of Neurosciences, Bambino Gesù Children’s Hospital, IRCCS, Rome (Italy)

2015-04-03

Rho-kinase (ROCK) has been well documented to play a key role in RhoA-induced actin remodeling. ROCK activation results in myosin light chain (MLC) phosphorylation either by direct action on MLC kinase (MLCK) or by inhibition of MLC phosphatase (MLCP), modulating actin–myosin contraction. We found that inhibition of the ROCK pathway in induced pluripotent stem cells, leads to nuclear export of HDAC7 and transcriptional activation of the orphan nuclear receptor NR4A1 while in cells with constitutive ROCK hyperactivity due to loss of function of the RhoGTPase activating protein Oligophrenin-1 (OPHN1), the orphan nuclear receptor NR4A1 is downregulated. Our study identify a new target of ROCK signaling via myosin phosphatase subunit (MYPT1) and Histone Deacetylase (HDAC7) at the nuclear level and provide new insights in the cellular functions of ROCK. - Highlights: • ROCK regulates nucleocytoplasmic shuttling of HDAC7 via phosphorylation of MYPT1. • Nuclear export of HDAC7 and upregulation of NR4A1 occurs with low ROCK activity. • High levels of ROCK activity due to OPHN1 loss of function downregulate NR4A1.

Nuclear localization of the CK2α-subunit correlates with poor prognosis in Clear Cell Renal Cell Carcinoma

DEFF Research Database (Denmark)

Rabjerg, Maj; Guerra, Barbara; Oliván-Viguera, Aida

2017-01-01

Protein kinase CK2a, one of the two catalytic isoforms of the protein kinase CK2 has been shown to contribute to tumor development, tumor proliferation and suppression of apoptosis in various malignancies. We conducted this study to investigate CK2 expression in different subtypes of Renal Cell...... Carcinoma (RCC) and in the benign oncocytoma. qRT-PCR, immunohistochemistry and Western blot analyses revealed that CK2a expression was significantly increased at the mRNA and protein levels in clear cell RCC (ccRCC). Also the kinase activity of CK2 was significantly increased in ccRCC compared to normal...... renal cortex. Nuclear protein expression of CK2a correlated in univariate analysis with poor Progression Free Survival (HR = 8.11, p = 0.016). Functional analyses (cell proliferation assay) revealed an inhibitory effect of Caki-2 cell growth following CK2 inhibition with CX-4945. Our results suggest...

Mitogen-activated protein kinases interacting kinases are autoinhibited by a reprogrammed activation segment.

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Jauch, Ralf; Cho, Min-Kyu; Jäkel, Stefan; Netter, Catharina; Schreiter, Kay; Aicher, Babette; Zweckstetter, Markus; Jäckle, Herbert; Wahl, Markus C

2006-09-06

Autoinhibition is a recurring mode of protein kinase regulation and can be based on diverse molecular mechanisms. Here, we show by crystal structure analysis, nuclear magnetic resonance (NMR)-based nucleotide affinity studies and rational mutagenesis that nonphosphorylated mitogen-activated protein (MAP) kinases interacting kinase (Mnk) 1 is autoinhibited by conversion of the activation segment into an autoinhibitory module. In a Mnk1 crystal structure, the activation segment is repositioned via a Mnk-specific sequence insertion at the N-terminal lobe with the following consequences: (i) the peptide substrate binding site is deconstructed, (ii) the interlobal cleft is narrowed, (iii) an essential Lys-Glu pair is disrupted and (iv) the magnesium-binding loop is locked into an ATP-competitive conformation. Consistently, deletion of the Mnk-specific insertion or removal of a conserved phenylalanine side chain, which induces a blockade of the ATP pocket, increase the ATP affinity of Mnk1. Structural rearrangements required for the activation of Mnks are apparent from the cocrystal structure of a Mnk2 D228G -staurosporine complex and can be modeled on the basis of crystal packing interactions. Our data suggest a novel regulatory mechanism specific for the Mnk subfamily.

eXpression2Kinases (X2K) Web: linking expression signatures to upstream cell signaling networks.

Science.gov (United States)

Clarke, Daniel J B; Kuleshov, Maxim V; Schilder, Brian M; Torre, Denis; Duffy, Mary E; Keenan, Alexandra B; Lachmann, Alexander; Feldmann, Axel S; Gundersen, Gregory W; Silverstein, Moshe C; Wang, Zichen; Ma'ayan, Avi

2018-05-25

While gene expression data at the mRNA level can be globally and accurately measured, profiling the activity of cell signaling pathways is currently much more difficult. eXpression2Kinases (X2K) computationally predicts involvement of upstream cell signaling pathways, given a signature of differentially expressed genes. X2K first computes enrichment for transcription factors likely to regulate the expression of the differentially expressed genes. The next step of X2K connects these enriched transcription factors through known protein-protein interactions (PPIs) to construct a subnetwork. The final step performs kinase enrichment analysis on the members of the subnetwork. X2K Web is a new implementation of the original eXpression2Kinases algorithm with important enhancements. X2K Web includes many new transcription factor and kinase libraries, and PPI networks. For demonstration, thousands of gene expression signatures induced by kinase inhibitors, applied to six breast cancer cell lines, are provided for fetching directly into X2K Web. The results are displayed as interactive downloadable vector graphic network images and bar graphs. Benchmarking various settings via random permutations enabled the identification of an optimal set of parameters to be used as the default settings in X2K Web. X2K Web is freely available from http://X2K.cloud.

Activation loop targeting strategy for design of receptor-interacting protein kinase 2 (RIPK2) inhibitors.

Science.gov (United States)

Suebsuwong, Chalada; Pinkas, Daniel M; Ray, Soumya S; Bufton, Joshua C; Dai, Bing; Bullock, Alex N; Degterev, Alexei; Cuny, Gregory D

2018-02-15

Development of selective kinase inhibitors remains a challenge due to considerable amino acid sequence similarity among family members particularly in the ATP binding site. Targeting the activation loop might offer improved inhibitor selectivity since this region of kinases is less conserved. However, the strategy presents difficulties due to activation loop flexibility. Herein, we report the design of receptor-interacting protein kinase 2 (RIPK2) inhibitors based on pan-kinase inhibitor regorafenib that aim to engage basic activation loop residues Lys169 or Arg171. We report development of CSR35 that displayed >10-fold selective inhibition of RIPK2 versus VEGFR2, the target of regorafenib. A co-crystal structure of CSR35 with RIPK2 revealed a resolved activation loop with an ionic interaction between the carboxylic acid installed in the inhibitor and the side-chain of Lys169. Our data provides principle feasibility of developing activation loop targeting type II inhibitors as a complementary strategy for achieving improved selectivity. Copyright © 2018 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Effect of starvation, diabetes and insulin on the casein kinase 2 from rat liver cytosol.

OpenAIRE

Martos, C; Plana, M; Guasch, M D; Itarte, E

1985-01-01

Starvation, diabetes and insulin did not alter the concentration of casein kinases in rat liver cytosol. However, the Km for casein of casein kinase 2 from diabetic rats was about 2-fold lower than that from control animals. Administration of insulin to control rats did not alter this parameter, but increased the Km for casein of casein kinase 2 in diabetic rats. Starvation did not affect the kinetic constants of casein kinases. The effect of diabetes on casein kinase 2 persisted after partia...

Mechanisms Governing DDK Regulation of the Initiation of DNA Replication

Directory of Open Access Journals (Sweden)

Larasati

2016-12-01

Full Text Available The budding yeast Dbf4-dependent kinase (DDK complex—comprised of cell division cycle (Cdc7 kinase and its regulatory subunit dumbbell former 4 (Dbf4—is required to trigger the initiation of DNA replication through the phosphorylation of multiple minichromosome maintenance complex subunits 2-7 (Mcm2-7. DDK is also a target of the radiation sensitive 53 (Rad53 checkpoint kinase in response to replication stress. Numerous investigations have determined mechanistic details, including the regions of Mcm2, Mcm4, and Mcm6 phosphorylated by DDK, and a number of DDK docking sites. Similarly, the way in which the Rad53 forkhead-associated 1 (FHA1 domain binds to DDK—involving both canonical and non-canonical interactions—has been elucidated. Recent work has revealed mutual promotion of DDK and synthetic lethal with dpb11-1 3 (Sld3 roles. While DDK phosphorylation of Mcm2-7 subunits facilitates their interaction with Sld3 at origins, Sld3 in turn stimulates DDK phosphorylation of Mcm2. Details of a mutually antagonistic relationship between DDK and Rap1-interacting factor 1 (Rif1 have also recently come to light. While Rif1 is able to reverse DDK-mediated Mcm2-7 complex phosphorylation by targeting the protein phosphatase glycogen 7 (Glc7 to origins, there is evidence to suggest that DDK can counteract this activity by binding to and phosphorylating Rif1.

A role for barley calcium-dependent protein kinase CPK2a in the response to drought

Directory of Open Access Journals (Sweden)

Agata Cieśla

2016-10-01

Full Text Available Increasing the drought tolerance of crops is one of the most challenging goals in plant breeding. To improve crop productivity during periods of water deficit, it is essential to understand the complex regulatory pathways that adapt plant metabolism to environmental conditions. Among various plant hormones and second messengers, calcium ions are known to be involved in drought stress perception and signaling. Plants have developed specific calcium-dependent protein kinases that convert calcium signals into phosphorylation events. In this study we attempted to elucidate the role of a calcium-dependent protein kinase in the drought stress response of barley (Hordeum vulgare L., one of the most economically important crops worldwide. The ongoing barley genome project has provided useful information about genes potentially involved in the drought stress response, but information on the role of calcium-dependent kinases is still limited. We found that the gene encoding the calcium-dependent protein kinase HvCPK2a was significantly upregulated in response to drought. To better understand the role of HvCPK2a in drought stress signaling, we generated transgenic Arabidopsis plants that overexpressed the corresponding coding sequence. Overexpressing lines displayed drought sensitivity, reduced nitrogen balance index, an increase in total chlorophyll content and decreased relative water content. In addition, in vitro kinase assay experiments combined with mass spectrometry allowed HvCPK2a autophosphorylation sites to be identified. Our results suggest that HvCPK2a is a dual-specificity calcium-dependent protein kinase that functions as a negative regulator of the drought stress response in barley.

The nuclear import of ribosomal proteins is regulated by mTOR

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Kazyken, Dubek; Kaz, Yelimbek; Kiyan, Vladimir; Zhylkibayev, Assylbek A.; Chen, Chien-Hung; Agarwal, Nitin K.; Sarbassov, Dos D.

2014-01-01

Mechanistic target of rapamycin (mTOR) is a central component of the essential signaling pathway that regulates cell growth and proliferation by controlling anabolic processes in cells. mTOR exists in two distinct mTOR complexes known as mTORC1 and mTORC2 that reside mostly in cytoplasm. In our study, the biochemical characterization of mTOR led to discovery of its novel localization on nuclear envelope where it associates with a critical regulator of nuclear import Ran Binding Protein 2 (RanBP2). We show that association of mTOR with RanBP2 is dependent on the mTOR kinase activity that regulates the nuclear import of ribosomal proteins. The mTOR kinase inhibitors within thirty minutes caused a substantial decrease of ribosomal proteins in the nuclear but not cytoplasmic fraction. Detection of a nuclear accumulation of the GFP-tagged ribosomal protein rpL7a also indicated its dependence on the mTOR kinase activity. The nuclear abundance of ribosomal proteins was not affected by inhibition of mTOR Complex 1 (mTORC1) by rapamycin or deficiency of mTORC2, suggesting a distinctive role of the nuclear envelope mTOR complex in the nuclear import. Thus, we identified that mTOR in association with RanBP2 mediates the active nuclear import of ribosomal proteins. PMID:25294810

Nuclear expression of Lyn, a Src family kinase member, is associated with poor prognosis in renal cancer patients.

Science.gov (United States)

Roseweir, Antonia K; Qayyum, Tahir; Lim, Zhi; Hammond, Rachel; MacDonald, Alasdair I; Fraser, Sioban; Oades, Grenville M; Aitchison, Michael; Jones, Robert J; Edwards, Joanne

2016-03-16

8000 cases of renal cancer are diagnosed each year in the UK, with a five-year survival rate of 50%. Treatment options are limited; a potential therapeutic target is the Src family kinases (SFKs). SFKs have roles in multiple oncogenic processes and promote metastases in solid tumours. The aim of this study was to investigate SFKs as potential therapeutic targets for clear cell renal cell carcinoma (ccRCC). SFKs expression was assessed in a tissue microarray consisting of 192 ccRCC patients with full clinical follow-up. SFK inhibitors, dasatinib and saracatinib, were assessed in early ccRCC cell lines, 786-O and 769-P and a metastatic ccRCC cell line, ACHN (± Src) for effects on protein expression, apoptosis, proliferation and wound healing. High nuclear expression of Lyn and the downstream marker of activation, paxillin, were associated with decreased patient survival. Conversely, high cytoplasmic expression of other SFK members and downstream marker of activation, focal adhesion kinase (FAK) were associated with increased patient survival. Treatment of non-metastatic 786-O and 769-P cells with dasatinib, dose dependently reduced SFK activation, shown via SFK (Y(419)) and FAK (Y(861)) phosphorylation, with no effect in metastatic ACHN cells. Dasatinib also increased apoptosis, while decreasing proliferation and migration in 786-O and 769-P cell lines, both in the presence and absence of Src protein. Our data suggests that nuclear Lyn is a potential therapeutic target for ccRCC and dasatinib affects cellular functions associated with cancer progression via a Src kinase independent mechanism.

Subcellular distribution of cyclin-dependent kinase-like 5 (CDKL5) is regulated through phosphorylation by dual specificity tyrosine-phosphorylation-regulated kinase 1A (DYRK1A).

Science.gov (United States)

Oi, Ami; Katayama, Syouichi; Hatano, Naoya; Sugiyama, Yasunori; Kameshita, Isamu; Sueyoshi, Noriyuki

2017-01-08

Cyclin-dependent kinase-like 5 (CDKL5) is a Ser/Thr protein kinase primarily expressed in the central nervous system and is known to cause X-linked neurodevelopmental disorders such as Rett syndrome. However, the mechanisms regulating CDKL5 have not yet been fully clarified. Therefore, in this study, we investigated the protein kinase that directly phosphorylates CDKL5, identifying it as dual specificity tyrosine-phosphorylation-regulated kinase 1A (DYRK1A), an enzyme binding to and phosphorylating CDKL5. We showed that subcellular distribution of CDKL5 was regulated by its phosphorylation by DYRK1A. In mouse neuroblastoma Neuro2a cells, CDKL5 was localized in both the cytosol and nucleus, whereas DYRK1A showed a typical nuclear localization. When CDKL5 and DYRK1A were co-expressed, the cytosolic localization of CDKL5 was significantly increased. Results of site-directed mutagenesis revealed that the phosphorylation site was Ser-308, in the vicinity of the nuclear localization signal. A mutation mimicking the phosphorylated serine residue by aspartate substitution (S308D) changed CDKL5 localization to the cytosol, whereas the corresponding alanine-substituted analog, CDKL5(S308A), was primarily localized to the nucleus. Taken together, these results strongly suggested that DYRK1A bound to CDKL5 and phosphorylated it on Ser-308, thus interfering with its nuclear localization. Copyright © 2016 Elsevier Inc. All rights reserved.

Structures of the inactive and active states of RIP2 kinase inform on the mechanism of activation.

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Erika Pellegrini

Full Text Available Innate immune receptors NOD1 and NOD2 are activated by bacterial peptidoglycans leading to recruitment of adaptor kinase RIP2, which, upon phosphorylation and ubiquitination, becomes a scaffold for downstream effectors. The kinase domain (RIP2K is a pharmaceutical target for inflammatory diseases caused by aberrant NOD2-RIP2 signalling. Although structures of active RIP2K in complex with inhibitors have been reported, the mechanism of RIP2K activation remains to be elucidated. Here we analyse RIP2K activation by combining crystal structures of the active and inactive states with mass spectrometric characterization of their phosphorylation profiles. The active state has Helix αC inwardly displaced and the phosphorylated Activation Segment (AS disordered, whilst in the inactive state Helix αC is outwardly displaced and packed against the helical, non-phosphorylated AS. Biophysical measurements show that the active state is a stable dimer whilst the inactive kinase is in a monomer-dimer equilibrium, consistent with the observed structural differences at the dimer interface. We conclude that RIP2 kinase auto-phosphorylation is intimately coupled to dimerization, similar to the case of BRAF. Our results will help drug design efforts targeting RIP2 as a potential treatment for NOD2-RIP2 related inflammatory diseases.

Deoxycytidine and Deoxythymidine Treatment for Thymidine Kinase 2 Deficiency.

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Lopez-Gomez, Carlos; Levy, Rebecca J; Sanchez-Quintero, Maria J; Juanola-Falgarona, Martí; Barca, Emanuele; Garcia-Diaz, Beatriz; Tadesse, Saba; Garone, Caterina; Hirano, Michio

2017-05-01

Thymidine kinase 2 (TK2), a critical enzyme in the mitochondrial pyrimidine salvage pathway, is essential for mitochondrial DNA (mtDNA) maintenance. Mutations in the nuclear gene, TK2, cause TK2 deficiency, which manifests predominantly in children as myopathy with mtDNA depletion. Molecular bypass therapy with the TK2 products, deoxycytidine monophosphate (dCMP) and deoxythymidine monophosphate (dTMP), prolongs the life span of Tk2-deficient (Tk2 -/- ) mice by 2- to 3-fold. Because we observed rapid catabolism of the deoxynucleoside monophosphates to deoxythymidine (dT) and deoxycytidine (dC), we hypothesized that: (1) deoxynucleosides might be the major active agents and (2) inhibition of deoxycytidine deamination might enhance dTMP+dCMP therapy. To test these hypotheses, we assessed two therapies in Tk2 -/- mice: (1) dT+dC and (2) coadministration of the deaminase inhibitor, tetrahydrouridine (THU), with dTMP+dCMP. We observed that dC+dT delayed disease onset, prolonged life span of Tk2-deficient mice and restored mtDNA copy number as well as respiratory chain enzyme activities and levels. In contrast, dCMP+dTMP+THU therapy decreased life span of Tk2 -/- animals compared to dCMP+dTMP. Our studies demonstrate that deoxynucleoside substrate enhancement is a novel therapy, which may ameliorate TK2 deficiency in patients. Ann Neurol 2017;81:641-652. © 2017 American Neurological Association.

Spindle-F Is the Central Mediator of Ik2 Kinase-Dependent Dendrite Pruning in Drosophila Sensory Neurons.

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Tzu Lin

2015-11-01

Full Text Available During development, certain Drosophila sensory neurons undergo dendrite pruning that selectively eliminates their dendrites but leaves the axons intact. How these neurons regulate pruning activity in the dendrites remains unknown. Here, we identify a coiled-coil protein Spindle-F (Spn-F that is required for dendrite pruning in Drosophila sensory neurons. Spn-F acts downstream of IKK-related kinase Ik2 in the same pathway for dendrite pruning. Spn-F exhibits a punctate pattern in larval neurons, whereas these Spn-F puncta become redistributed in pupal neurons, a step that is essential for dendrite pruning. The redistribution of Spn-F from puncta in pupal neurons requires the phosphorylation of Spn-F by Ik2 kinase to decrease Spn-F self-association, and depends on the function of microtubule motor dynein complex. Spn-F is a key component to link Ik2 kinase to dynein motor complex, and the formation of Ik2/Spn-F/dynein complex is critical for Spn-F redistribution and for dendrite pruning. Our findings reveal a novel regulatory mechanism for dendrite pruning achieved by temporal activation of Ik2 kinase and dynein-mediated redistribution of Ik2/Spn-F complex in neurons.

Insulin signaling inhibits the 5-HT2C receptor in choroid plexus via MAP kinase

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Guan Kunliang

2003-06-01

Full Text Available Abstract Background G protein-coupled receptors (GPCRs interact with heterotrimeric GTP-binding proteins (G proteins to modulate acute changes in intracellular messenger levels and ion channel activity. In contrast, long-term changes in cellular growth, proliferation and differentiation are often mediated by tyrosine kinase receptors and certain GPCRs by activation of mitogen-activated protein (MAP kinases. Complex interactions occur between these signaling pathways, but the specific mechanisms of such regulatory events are not well-understood. In particular it is not clear whether GPCRs are modulated by tyrosine kinase receptor-MAP kinase pathways. Results Here we describe tyrosine kinase receptor regulation of a GPCR via MAP kinase. Insulin reduced the activity of the 5-HT2C receptor in choroid plexus cells which was blocked by the MAP kinase kinase (MEK inhibitor, PD 098059. We demonstrate that the inhibitory effect of insulin and insulin-like growth factor type 1 (IGF-1 on the 5-HT2C receptor is dependent on tyrosine kinase, RAS and MAP kinase. The effect may be receptor-specific: insulin had no effect on another GPCR that shares the same G protein signaling pathway as the 5-HT2C receptor. This effect is also direct: activated MAP kinase mimicked the effect of insulin, and removing a putative MAP kinase site from the 5-HT2C receptor abolished the effect of insulin. Conclusion These results show that insulin signaling can inhibit 5-HT2C receptor activity and suggest that MAP kinase may play a direct role in regulating the function of a specific GPCR.

Lipid Signaling via Pkh1/2 Regulates Fungal CO2 Sensing through the Kinase Sch9

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Susann Pohlers

2017-01-01

Full Text Available Adaptation to alternating CO2 concentrations is crucial for all organisms. Carbonic anhydrases—metalloenzymes that have been found in all domains of life—enable fixation of scarce CO2 by accelerating its conversion to bicarbonate and ensure maintenance of cellular metabolism. In fungi and other eukaryotes, the carbonic anhydrase Nce103 has been shown to be essential for growth in air (~0.04% CO2. Expression of NCE103 is regulated in response to CO2 availability. In Saccharomyces cerevisiae, NCE103 is activated by the transcription factor ScCst6, and in Candida albicans and Candida glabrata, it is activated by its homologues CaRca1 and CgRca1, respectively. To identify the kinase controlling Cst6/Rca1, we screened an S. cerevisiae kinase/phosphatase mutant library for the ability to regulate NCE103 in a CO2-dependent manner. We identified ScSch9 as a potential ScCst6-specific kinase, as the sch9Δ mutant strain showed deregulated NCE103 expression on the RNA and protein levels. Immunoprecipitation revealed the binding capabilities of both proteins, and detection of ScCst6 phosphorylation by ScSch9 in vitro confirmed Sch9 as the Cst6 kinase. We could show that CO2-dependent activation of Sch9, which is part of a kinase cascade, is mediated by lipid/Pkh1/2 signaling but not TORC1. Finally, we tested conservation of the identified regulatory cascade in the pathogenic yeast species C. albicans and C. glabrata. Deletion of SCH9 homologues of both species impaired CO2-dependent regulation of NCE103 expression, which indicates a conservation of the CO2 adaptation mechanism among yeasts. Thus, Sch9 is a Cst6/Rca1 kinase that links CO2 adaptation to lipid signaling via Pkh1/2 in fungi.

A protective role of nuclear factor-erythroid 2-related factor-2 (Nrf2) in inflammatory disorders

International Nuclear Information System (INIS)

Kim, Jiyoung; Cha, Young-Nam; Surh, Young-Joon

2010-01-01

Nuclear factor-erythroid 2-related factor-2 (Nrf2) is a key transcription factor that plays a central role in cellular defense against oxidative and electrophilic insults by timely induction of antioxidative and phase-2 detoxifying enzymes and related stress-response proteins. The 5'-flanking regions of genes encoding these cytoprotective proteins contain a specific consensus sequence termed antioxidant response element (ARE) to which Nrf2 binds. Recent studies have demonstrated that Nrf2-ARE signaling is also involved in attenuating inflammation-associated pathogenesis, such as autoimmune diseases, rheumatoid arthritis, asthma, emphysema, gastritis, colitis and atherosclerosis. Thus, disruption or loss of Nrf2 signaling causes enhanced susceptibility not only to oxidative and electrophilic stresses but also to inflammatory tissue injuries. During the early-phase of inflammation-mediated tissue damage, activation of Nrf2-ARE might inhibit the production or expression of pro-inflammatory mediators including cytokines, chemokines, cell adhesion molecules, matrix metalloproteinases, cyclooxygenase-2 and inducible nitric oxide synthase. It is likely that the cytoprotective function of genes targeted by Nrf2 may cooperatively regulate the innate immune response and also repress the induction of pro-inflammatory genes. This review highlights the protective role of Nrf2 in inflammation-mediated disorders with special focus on the inflammatory signaling modulated by this redox-regulated transcription factor.

Peptide microarray analysis of substrate specificity of the transmembrane Ser/Thr kinase KPI-2 reveals reactivity with cystic fibrosis transmembrane conductance regulator and phosphorylase.

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Wang, Hong; Brautigan, David L

2006-11-01

Human lemur (Lmr) kinases are predicted to be Tyr kinases based on sequences and are related to neurotrophin receptor Trk kinases. This study used homogeneous recombinant KPI-2 (Lmr2, LMTK2, Cprk, brain-enriched protein kinase) kinase domain and a library of 1,154 peptides on a microarray to analyze substrate specificity. We found that KPI-2 is strictly a Ser/Thr kinase that reacts with Ser either preceded by or followed by Pro residues but unlike other Pro-directed kinases does not strictly require an adjacent Pro residue. The most reactive peptide in the library corresponds to Ser-737 of cystic fibrosis transmembrane conductance regulator, and the recombinant R domain of cystic fibrosis transmembrane conductance regulator was a preferred substrate. Furthermore the KPI-2 kinase phosphorylated peptides corresponding to the single site in phosphorylase and purified phosphorylase b, making this only the second known phosphorylase b kinase. Phosphorylase was used as a specific substrate to show that KPI-2 is inhibited in living cells by addition of nerve growth factor or serum. The results demonstrate the utility of the peptide library to probe specificity and discover kinase substrates and offer a specific assay that reveals hormonal regulation of the activity of this unusual transmembrane kinase.

Evidence for in vivo phosphorylation of the Grb2 SH2-domain binding site on focal adhesion kinase by Src-family protein-tyrosine kinases.

OpenAIRE

Schlaepfer, D D; Hunter, T

1996-01-01

Focal adhesion kinase (FAK) is a nonreceptor protein-tyrosine kinase (PTK) that associates with integrin receptors and participates in extracellular matrix-mediated signal transduction events. We showed previously that the c-Src nonreceptor PTK and the Grb2 SH2/SH3 adaptor protein bound directly to FAK after fibronectin stimulation (D. D. Schlaepfer, S.K. Hanks, T. Hunter, and P. van der Geer, Nature [London] 372:786-791, 1994). Here, we present evidence that c-Src association with FAK is req...

The Pim kinases: new targets for drug development.

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Swords, Ronan; Kelly, Kevin; Carew, Jennifer; Nawrocki, Stefan; Mahalingam, Devalingam; Sarantopoulos, John; Bearss, David; Giles, Francis

2011-12-01

The three Pim kinases are a small family of serine/threonine kinases regulating several signaling pathways that are fundamental to cancer development and progression. They were first recognized as pro-viral integration sites for the Moloney Murine Leukemia virus. Unlike other kinases, they possess a hinge region which creates a unique binding pocket for ATP. Absence of a regulatory domain means that these proteins are constitutively active once transcribed. Pim kinases are critical downstream effectors of the ABL (ableson), JAK2 (janus kinase 2), and Flt-3 (FMS related tyrosine kinase 1) oncogenes and are required by them to drive tumorigenesis. Recent investigations have established that the Pim kinases function as effective inhibitors of apoptosis and when overexpressed, produce resistance to the mTOR (mammalian target of rapamycin) inhibitor, rapamycin . Overexpression of the PIM kinases has been reported in several hematological and solid tumors (PIM 1), myeloma, lymphoma, leukemia (PIM 2) and adenocarcinomas (PIM 3). As such, the Pim kinases are a very attractive target for pharmacological inhibition in cancer therapy. Novel small molecule inhibitors of the human Pim kinases have been designed and are currently undergoing preclinical evaluation.

Regulation of the vertebrate cell cycle by the cdc2 protein kinase

International Nuclear Information System (INIS)

Draetta, G.; Brizuela, L.; Moran, B.; Beach, D.

1988-01-01

A homolog of the cdc2/CDC28 protein kinase of yeast is found in all vertebrate species that have been investigated. Human cdc2 exists as a complex with a 13-kD protein that is homologous to the suc1 gene product of fission yeast. In both human and fission yeast cells, the protein kinase also exists in a complex with a 62-kD polypeptide that has not been identified genetically but acts as a substrate in vitro. The authors have studied the properties of the protein kinase in rat and human cells, as well as in Xenopus eggs. They find that in baby rat kidney (BRK) cells, which are quiescent in cell culture, the cdc2 protein is not synthesized. However, synthesis is rapidly induced in response to proliferative activation by infection with adenovirus. In human HeLa cells, the protein kinase is present continuously. It behaves as a cell-cycle oscillator that is inactive in G 1 but displays maximal enzymatic activity during mitotic metaphase. These observations indicate that in a wide variety of vertebrate cells, the cdc2 protein kinase is involved in regulating mitosis. The authors' approach taken toward study of the cdc2 protein kinase highlights the possibilities that now exist for combining the advantages of ascomycete genetics with the cell-free systems of Xenopus and the biochemical advantages of tissue culture cells to investigate fundamental problems of the cell cycle

Inhibition of protein kinase C induces differentiation in Neuro-2a cells

International Nuclear Information System (INIS)

Minana, M.D.; Felipo, V.; Grisolia, S.

1990-01-01

1-(5-Isoquinolinylsulfonyl)-2-methylpiperazine (H7), a potent inhibitor of protein kinase C, induced neuritogenesis in Neuro-2a cells, whereas N-(2-guanidinoethyl)-5-isoquinolinesulfonamide (HA 1004), which inhibits more efficiently cAMP- and cGMP-dependent protein kinases, did not. The effect, noticeable after 3 hr, was maximum (13-fold increase at 500 μM H7) between 1 and 3 days and was maintained over 2 months. In controls, 90% of the cells were undifferentiated, whereas after 3 hr with 500 μM H7 only 25% of the cells remained undifferentiated. DNA synthesis decreased as the number of differentiated cells increased. Differentiation is also functional since acetylcholinesterase activity increased ∼7-fold after 48 hr with 500 μM H7. Phorbol 12-myristate 13-acetate, a specific activator of protein kinase C, prevented or reversed the induction of neuritogenesis and the inhibition of DNA synthesis by H7. There is a good correlation between the level of protein kinase C and the percentage of differentiated cells. The results indicate that protein kinase C may play a key role in the control of differentiation of neural cells. Some possible clinical implications are briefly discussed

Prostaglandin E2 stimulates the expression of cumulus expansion-related genes in pigs: the role of protein kinase B

Czech Academy of Sciences Publication Activity Database

Blaha, Milan; Procházka, Radek; Adámková, K.; Nevoral, J.; Němcová, Lucie

2017-01-01

Roč. 130, č. 2 (2017), s. 38-46 ISSN 1098-8823 R&D Projects: GA MZe(CZ) QJ1510138; GA MŠk EF15_003/0000460 Institutional support: RVO:67985904 Keywords : cumulus * oocyte * prostaglandin E2 * protein kinase B Subject RIV: EB - Genetics ; Molecular Biology OBOR OECD: Reproductive biology (medical aspects to be 3) Impact factor: 2.640, year: 2016

Effect of triiodothyronine on rat liver chromatin protein kinase

International Nuclear Information System (INIS)

Kruh, J.; Tichonicky, L.

1976-01-01

1) Injection of triiodothyronine to rats stimulates protein kinase activity in liver chromatin nonhistone proteins. A significant increase was found after two daily injections. A 4-fold increase was observed with the purified enzyme after eight daily injections of the hormone. No variations were observed in cytosol protein kinase activity. Electrophoretic pattern, effect of heat denaturation, effect of p-hydroxymercuribenzoate seem to indicate that the enzyme present in treated rats is not identical to the enzyme in control animals, which suggests that thyroid hormone has induced nuclear protein kinase. Diiodothyronine, 3, 3', 5'-triiodothyronine have no effect on protein kinase. 2) Chromatin non-histone proteins isolated from rats injected with triiodothyronine incorporated more 32 P when incubated with [γ- 32 P]ATP than the chromatin proteins from untreated rats. Thyroidectomy reduced the in vitro 32 P incorporation. It is suggested that some of the biological activity of thyroid hormone could be mediated through its effect on chromatin non-histone proteins. (orig.) [de

Blue Light-excited Light-Oxygen-Voltage-sensing Domain 2 (LOV2) Triggers a Rearrangement of the Kinase Domain to Induce Phosphorylation Activity in Arabidopsis Phototropin1.

Science.gov (United States)

Oide, Mao; Okajima, Koji; Kashojiya, Sachiko; Takayama, Yuki; Oroguchi, Tomotaka; Hikima, Takaaki; Yamamoto, Masaki; Nakasako, Masayoshi

2016-09-16

Phototropin1 is a blue light (BL) receptor in plants and shows BL-dependent kinase activation. The BL-excited light-oxygen-voltage-sensing domain 2 (LOV2) is primarily responsible for the activation of the kinase domain; however, the molecular mechanism by which conformational changes in LOV2 are transmitted to the kinase domain remains unclear. Here, we investigated BL-induced structural changes of a minimum functional fragment of Arabidopsis phototropin1 composed of LOV2, the kinase domain, and a linker connecting the two domains using small-angle x-ray scattering (SAXS). The fragment existed as a dimer and displayed photoreversible SAXS changes reflected in the radii of gyration of 42.9 Å in the dark and 48.8 Å under BL irradiation. In the dark, the molecular shape reconstructed from the SAXS profiles appeared as two bean-shaped lobes in a twisted arrangement that was 170 Å long, 80 Å wide, and 50 Å thick. The molecular shape under BL became slightly elongated from that in the dark. By fitting the crystal structure of the LOV2 dimer and a homology model of the kinase domain to their inferred shapes, the BL-dependent change could be interpreted as the positional shift in the kinase domain relative to that of the LOV2 dimer. In addition, we found that lysine 475, a functionally important residue, in the N-terminal region of LOV2 plays a critical role in transmitting the structural changes in LOV2 to the kinase domain. The interface between the domains is critical for signaling, suitably changing the structure to activate the kinase in response to conformational changes in the adjoining LOV2. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Photoactivatable Caged Prodrugs of VEGFR-2 Kinase Inhibitors

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Boris Pinchuk

2016-04-01

Full Text Available In this study, we report on the design, synthesis, photokinetic properties and in vitro evaluation of photoactivatable caged prodrugs for the receptor tyrosine kinase VEGFR-2. Highly potent VEGFR-2 inhibitors 1 and 3 were caged by introduction of a photoremovable protecting group (PPG to yield the caged prodrugs 4 and 5. As expected, enzymatic and cellular proliferation assays showed dramatically diminished efficacy of caged prodrugs in vitro. Upon ultraviolet (UV irradiation of the prodrugs original inhibitory activity was completely restored and even distinctly reinforced, as was the case for the prodrug 4. The presented results are a further evidence for caging technique being an interesting approach in the protein kinase field. It could enable spatial and temporal control for the inhibition of VEGFR-2. The described photoactivatable prodrugs might be highly useful as biological probes for studying the VEGFR-2 signal transduction.

Decree of the State Office for Nuclear Safety No. 147/1997 of 17 June 1997 specifying lists of selected nuclear-related items and dual-use nuclear-related items

International Nuclear Information System (INIS)

1997-01-01

The core of the Decree consists of 2 lists, viz (a) the List of Selected Items (selected nuclear-related materials, equipment and technologies) which are subject to control regimes during imports, exports and transit; and (b) the List of Dual-Use Items (dual-use nuclear-related materials, equipment and technologies) which are subject to control regimes during imports and exports. Both Lists are based on the IAEA document INFCIRC/254/Rev.2/Part 2/Mod.1. (P.A.)

Novel autophosphorylation sites of Src family kinases regulate kinase activity and SH2 domain-binding capacity.

Science.gov (United States)

Weir, Marion E; Mann, Jacqueline E; Corwin, Thomas; Fulton, Zachary W; Hao, Jennifer M; Maniscalco, Jeanine F; Kenney, Marie C; Roman Roque, Kristal M; Chapdelaine, Elizabeth F; Stelzl, Ulrich; Deming, Paula B; Ballif, Bryan A; Hinkle, Karen L

2016-04-01

Src family tyrosine kinases (SFKs) are critical players in normal and aberrant biological processes. While phosphorylation importantly regulates SFKs at two known tyrosines, large-scale phosphoproteomics have revealed four additional tyrosines commonly phosphorylated in SFKs. We found these novel tyrosines to be autophosphorylation sites. Mimicking phosphorylation at the C-terminal site to the activation loop decreased Fyn activity. Phosphomimetics and direct phosphorylation at the three SH2 domain sites increased Fyn activity while reducing phosphotyrosine-dependent interactions. While 68% of human SH2 domains exhibit conservation of at least one of these tyrosines, few have been found phosphorylated except when found in cis to a kinase domain. © 2016 Federation of European Biochemical Societies.

Proinflammatory effect of sodium 4-phenylbutyrate in deltaF508-cystic fibrosis transmembrane conductance regulator lung epithelial cells: involvement of extracellular signal-regulated protein kinase 1/2 and c-Jun-NH2-terminal kinase signaling.

Science.gov (United States)

Roque, Telma; Boncoeur, Emilie; Saint-Criq, Vinciane; Bonvin, Elise; Clement, Annick; Tabary, Olivier; Jacquot, Jacky

2008-09-01

Sodium 4-phenylbutyrate (4-PBA) has attracted a great deal of attention in cystic fibrosis (CF) pathology due to its capacity to traffic DeltaF508-cystic fibrosis transmembrane conductance regulator (CFTR) to the cell membrane and restore CFTR chloride function at the plasma membrane of CF lung cells in vitro and in vivo. Using two different DeltaF508-CFTR lung epithelial cell lines (CFBE41o- and IB3-1 cells, characterized with DeltaF508-homozygous and heterozygous genotype, respectively) in vitro, 4-PBA induced an increase of proinflammatory cytokine interleukin (IL)-8 production in a concentration-dependent manner. This 4-PBA-induced IL-8 production was associated with a strong reduction of proteasome and nuclear factor-kappaB transcriptional activities in the two DeltaF508-CFTR lung cells either in a resting state or after tumor necrosis factor-alpha stimulation. In contrast, a strong increase of activator protein-1 transcriptional activity was observed. The inhibition of extracellular signal-regulated protein kinase 1/2 (ERK1/2) by 1,4-diamino-2,3-dicyano-1,4-bis[2-aminophenylthio] butadiene (U0126) and 2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one (PD98059) and c-Jun-NH(2)-terminal kinase (JNK) mitogen-activated protein kinase (MAPK) by anthra[1,9-cd] pyrazol-6 (2H)-one (SP600125), respectively, was associated with a reduction (2-3.5-fold) of IL-8 production in both DeltaF508-CFTR lung cell lines treated with 4-PBA. No significant change of IL-8 production was observed after an inhibition of p38 MAPK with 4-[4-(4-fluorophenyl)-5-(4-pyridinyl)-1H-imidazol-2-yl] phenol (SB202190). Therefore, we suggest that inhibition of both ERK1/2 and JNK signaling may be a means to strongly reduce 4-PBA-induced IL-8 production in combination with 4-PBA treatment to restore CFTR Cl(-) channel function in lung epithelial cells of patients with CF.

Malondialdehyde inhibits an AMPK-mediated nuclear translocation and repression activity of ALDH2 in transcription

International Nuclear Information System (INIS)

Choi, Ji-Woong; Kim, Jae-Hwan; Cho, Sung-Chun; Ha, Moon-Kyung; Song, Kye-Yong; Youn, Hong-Duk; Park, Sang Chul

2011-01-01

Research highlights: → ALDH2 is an MDA-modified protein in old rat kidney tissues. → AMPK associates with ALDH2 and triggers the nuclear localization of ALDH2. → ALDH2 serves as a general transcriptional repressor by associating with HDACs. → MDA inhibits the AMPK-mediated translocation of ALDH2 and its repression activity. -- Abstract: Aging process results from deleterious damages by reactive oxygen species, in particular, various metabolic aldehydes. Aldehyde dehydrogenase 2 (ALDH2) is one of metabolic enzymes detoxifying various aldehydes under oxidative conditions. AMP-activated protein kinase (AMPK) plays a key role in controlling metabolic process. However, little was known about the relationship of ALDH2 with AMPK under oxidative conditions. Here, we, by using MDA-specific monoclonal antibody, screened the tissues of young and old rats for MDA-modified proteins and identified an ALDH2 as a prominent MDA-modified protein band in the old rat kidney tissue. ALDH2 associates with AMPK and is phosphorylated by AMPK. In addition, AICAR, an activator of AMP-activated protein kinase, induces the nuclear translocation of ALDH2. ALDH2 in nucleus is involved in general transcription repression by association with histone deacetylases. Furthermore, MDA modification inhibited the translocation of ALDH2 and the association with AMPK, and ultimately led to de-repression of transcription in the reporter system analysis. In this study, we have demonstrated that ALDH2 acts as a transcriptional repressor in response to AMPK activation, and MDA modifies ALDH2 and inhibits repressive activity of ALDH2 in general transcription. We thus suggest that increasing amount of MDA during aging process may interrupt the nuclear function of ALDH2, modulated by AMPK.

Malondialdehyde inhibits an AMPK-mediated nuclear translocation and repression activity of ALDH2 in transcription

Energy Technology Data Exchange (ETDEWEB)

Choi, Ji-Woong [Department of Biomedical Sciences and Biochemistry and Molecular Biology, Seoul National University College of Medicine, 28 Yongon-dong, Chongro-gu, Seoul 110-799 (Korea, Republic of); Aging and Apoptosis Research Center (AARC), Seoul National University College of Medicine, 28 Yongon-dong, Chongro-gu, Seoul 110-799, (Korea, Republic of); Kim, Jae-Hwan [Department of Biomedical Sciences and Biochemistry and Molecular Biology, Seoul National University College of Medicine, 28 Yongon-dong, Chongro-gu, Seoul 110-799 (Korea, Republic of); Cho, Sung-Chun; Ha, Moon-Kyung [Department of Biomedical Sciences and Biochemistry and Molecular Biology, Seoul National University College of Medicine, 28 Yongon-dong, Chongro-gu, Seoul 110-799 (Korea, Republic of); Aging and Apoptosis Research Center (AARC), Seoul National University College of Medicine, 28 Yongon-dong, Chongro-gu, Seoul 110-799, (Korea, Republic of); Song, Kye-Yong [Department of Pathology, Chung-Ang University College of Medicine, Seoul 156-756 (Korea, Republic of); Youn, Hong-Duk, E-mail: hdyoun@snu.ac.kr [Department of Biomedical Sciences and Biochemistry and Molecular Biology, Seoul National University College of Medicine, 28 Yongon-dong, Chongro-gu, Seoul 110-799 (Korea, Republic of); Park, Sang Chul, E-mail: scpark@snu.ac.kr [Department of Biomedical Sciences and Biochemistry and Molecular Biology, Seoul National University College of Medicine, 28 Yongon-dong, Chongro-gu, Seoul 110-799 (Korea, Republic of); Aging and Apoptosis Research Center (AARC), Seoul National University College of Medicine, 28 Yongon-dong, Chongro-gu, Seoul 110-799, (Korea, Republic of)

2011-01-07

Research highlights: {yields} ALDH2 is an MDA-modified protein in old rat kidney tissues. {yields} AMPK associates with ALDH2 and triggers the nuclear localization of ALDH2. {yields} ALDH2 serves as a general transcriptional repressor by associating with HDACs. {yields} MDA inhibits the AMPK-mediated translocation of ALDH2 and its repression activity. -- Abstract: Aging process results from deleterious damages by reactive oxygen species, in particular, various metabolic aldehydes. Aldehyde dehydrogenase 2 (ALDH2) is one of metabolic enzymes detoxifying various aldehydes under oxidative conditions. AMP-activated protein kinase (AMPK) plays a key role in controlling metabolic process. However, little was known about the relationship of ALDH2 with AMPK under oxidative conditions. Here, we, by using MDA-specific monoclonal antibody, screened the tissues of young and old rats for MDA-modified proteins and identified an ALDH2 as a prominent MDA-modified protein band in the old rat kidney tissue. ALDH2 associates with AMPK and is phosphorylated by AMPK. In addition, AICAR, an activator of AMP-activated protein kinase, induces the nuclear translocation of ALDH2. ALDH2 in nucleus is involved in general transcription repression by association with histone deacetylases. Furthermore, MDA modification inhibited the translocation of ALDH2 and the association with AMPK, and ultimately led to de-repression of transcription in the reporter system analysis. In this study, we have demonstrated that ALDH2 acts as a transcriptional repressor in response to AMPK activation, and MDA modifies ALDH2 and inhibits repressive activity of ALDH2 in general transcription. We thus suggest that increasing amount of MDA during aging process may interrupt the nuclear function of ALDH2, modulated by AMPK.

The effect of G protein-coupled receptor kinase 2 (GRK2) on lactation and on proliferation of mammary epithelial cells from dairy cows.

Science.gov (United States)

Hou, Xiaoming; Hu, Hongliu; Lin, Ye; Qu, Bo; Gao, Xuejun; Li, Qingzhang

2016-07-01

Milk protein is an important component of milk and a nutritional source for human consumption. To better understand the molecular events underlying synthesis of milk proteins, the global gene expression patterns in mammary glands of dairy cow with high-quality milk (>3% milk protein; >3.5% milk fat) and low-quality milk (milk protein; milk fat) were examined via digital gene expression study. A total of 139 upregulated and 66 downregulated genes were detected in the mammary tissues of lactating cows with high-quality milk compared with the tissues of cows with low-quality milk. A pathway enrichment study of these genes revealed that the top 5 pathways that were differentially affected in the tissues of cows with high- versus low-quality milk involved metabolic pathways, cancer, cytokine-cytokine receptor interactions, regulation of the actin cytoskeleton, and insulin signaling. We also found that the G protein-coupled receptor kinase 2 (GRK2) was one of the most highly upregulated genes in lactating mammary tissue with low-quality milk compared with tissue with high-quality milk. The knockdown of GRK2 in cultured bovine mammary epithelial cells enhanced CSN2 expression and activated signaling molecules related to translation, including protein kinase B, mammalian target of rapamycin, and p70 ribosomal protein S6 kinase 1 (S6K1), whereas overexpression of GRK2 had the opposite effects. However, expression of genes involved in the mitogen-activated protein kinase pathway was positively regulated by GRK2. Therefore, GRK2 seems to act as a negative mediator of milk-protein synthesis via the protein kinase B-mammalian target of rapamycin signaling axis. Furthermore, GRK2 may negatively control milk-protein synthesis by activating the mitogen-activated protein kinase pathway in dairy cow mammary epithelial cells. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

A protective role of nuclear factor-erythroid 2-related factor-2 (Nrf2) in inflammatory disorders

Energy Technology Data Exchange (ETDEWEB)

Kim, Jiyoung [National Research Laboratory, College of Pharmacy, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 151-742 (Korea, Republic of); Cha, Young-Nam [Inha University College of Medicine, Incheon 382-751 (Korea, Republic of); Surh, Young-Joon, E-mail: surh@plaza.snu.ac.kr [National Research Laboratory, College of Pharmacy, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 151-742 (Korea, Republic of); Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 151-742 (Korea, Republic of); Cancer Research Institute, Seoul National University, Seoul 110-799 (Korea, Republic of)

2010-08-07

Nuclear factor-erythroid 2-related factor-2 (Nrf2) is a key transcription factor that plays a central role in cellular defense against oxidative and electrophilic insults by timely induction of antioxidative and phase-2 detoxifying enzymes and related stress-response proteins. The 5'-flanking regions of genes encoding these cytoprotective proteins contain a specific consensus sequence termed antioxidant response element (ARE) to which Nrf2 binds. Recent studies have demonstrated that Nrf2-ARE signaling is also involved in attenuating inflammation-associated pathogenesis, such as autoimmune diseases, rheumatoid arthritis, asthma, emphysema, gastritis, colitis and atherosclerosis. Thus, disruption or loss of Nrf2 signaling causes enhanced susceptibility not only to oxidative and electrophilic stresses but also to inflammatory tissue injuries. During the early-phase of inflammation-mediated tissue damage, activation of Nrf2-ARE might inhibit the production or expression of pro-inflammatory mediators including cytokines, chemokines, cell adhesion molecules, matrix metalloproteinases, cyclooxygenase-2 and inducible nitric oxide synthase. It is likely that the cytoprotective function of genes targeted by Nrf2 may cooperatively regulate the innate immune response and also repress the induction of pro-inflammatory genes. This review highlights the protective role of Nrf2 in inflammation-mediated disorders with special focus on the inflammatory signaling modulated by this redox-regulated transcription factor.

Ser2 is the autophosphorylation site in the beta subunit from bicistronically expressed human casein kinase-2 and from native rat liver casein kinase-2 beta

DEFF Research Database (Denmark)

Boldyreff, B; James, P; Staudenmann, W

1993-01-01

Human casein kinase-2 (CK-2) subunits alpha and beta were bicistronically expressed in bacteria. The recombinant holoenzyme shared all investigated properties with the native CK-2 from mammalian sources (rat liver, Krebs II mouse ascites tumour cells). Contrary to recombinant human CK-2 produced...

The IkappaB kinase family phosphorylates the Parkinson's disease kinase LRRK2 at Ser935 and Ser910 during Toll-like receptor signaling.

Directory of Open Access Journals (Sweden)

Nicolas Dzamko

Full Text Available Mutations in leucine-rich repeat kinase 2 (LRRK2 are strongly associated with late-onset autosomal dominant Parkinson's disease. LRRK2 is highly expressed in immune cells and recent work points towards a link between LRRK2 and innate immunity. Here we demonstrate that stimulation of the Toll-Like Receptor (TLR pathway by MyD88-dependent agonists in bone marrow-derived macrophages (BMDMs or RAW264.7 macrophages induces marked phosphorylation of LRRK2 at Ser910 and Ser935, the phosphorylation sites that regulate the binding of 14-3-3 to LRRK2. Phosphorylation of these residues is prevented by knock-out of MyD88 in BMDMs, but not the alternative TLR adaptor protein TRIF. Utilising both pharmacological inhibitors, including a new TAK1 inhibitor, NG25, and genetic models, we provide evidence that both the canonical (IKKα and IKKβ and IKK-related (IKKε and TBK1 kinases mediate TLR agonist induced phosphorylation of LRRK2 in vivo. Moreover, all four IKK members directly phosphorylate LRRK2 at Ser910 and Ser935 in vitro. Consistent with previous work describing Ser910 and Ser935 as pharmacodynamic biomarkers of LRRK2 activity, we find that the TLR independent basal phosphorylation of LRRK2 at Ser910 and Ser935 is abolished following treatment of macrophages with LRRK2 kinase inhibitors. However, the increased phosphorylation of Ser910 and Ser935 induced by activation of the MyD88 pathway is insensitive to LRRK2 kinase inhibitors. Finally, employing LRRK2-deficient BMDMs, we present data indicating that LRRK2 does not play a major role in regulating the secretion of inflammatory cytokines induced by activation of the MyD88 pathway. Our findings provide the first direct link between LRRK2 and the IKKs that mediate many immune responses. Further work is required to uncover the physiological roles that phosphorylation of LRRK2 by IKKs play in controlling macrophage biology and to determine how phosphorylation of LRRK2 by IKKs impacts upon the use of Ser

Sphingosine kinase 2-deficiency mediated changes in spinal pain processing

Directory of Open Access Journals (Sweden)

Jastrow eCanlas

2015-08-01

Full Text Available Chronic pain is one of the most burdensome health issues facing the planet (as costly as diabetes and cancer combined, and in desperate need for new diagnostic targets leading to better therapies. The bioactive lipid sphingosine 1-phosphate (S1P and its receptors have recently been shown to modulate nociceptive signalling at the level of peripheral nociceptors and central neurons. However, the exact role of S1P generating enzymes, in particular sphingosine kinase 2 (Sphk2, in nociception remains unknown. We found that both sphingosine kinases, Sphk1 and Sphk2, were expressed in spinal cord with higher levels of Sphk2 mRNA compared to Sphk1. All three Sphk2 mRNA-isoforms were present with the Sphk2.1 mRNA showing the highest relative expression. Mice deficient in Sphk2 (Sphk2-/- showed in contrast to mice deficient in Sphk1 (Sphk1-/- substantially lower spinal S1P levels compared to wild-type C57BL/6 mice. In the formalin model of acute peripheral inflammatory pain, Sphk2-/- mice showed facilitation of nociceptive transmission during the late response, whereas responses to early acute pain, and the number of c-Fos immunoreactive dorsal horn neurons were not different between Sphk2-/- and wild-type mice. Chronic peripheral inflammation (CPI caused a bilateral increase in mechanical sensitivity in Sphk2-/- mice. Additionally, CPI increased the relative mRNA expression of P2X4 receptor, brain-derived neurotrophic factor and inducible nitric oxide synthase in the ipsilateral spinal cord of wild-type but not Sphk2-/- mice. Similarly, Sphk2-/- mice showed in contrast to wild-type no CPI-dependent increase in areas of the dorsal horn immunoreactive for the microglia marker Iba-1 and the astrocyte marker GFAP. Our results suggest that the tightly regulated cell signalling enzyme Sphk2 may be a key component for facilitation of nociceptive circuits in the CNS leading to central sensitization and pain memory formation.

Sensitization of human colon cancer cells to sodium butyrate-induced apoptosis by modulation of sphingosine kinase 2 and protein kinase D

International Nuclear Information System (INIS)

Xiao, Min; Liu, Yungang; Zou, Fei

2012-01-01

Sphingosine kinases (SphKs) have been recognized as important proteins regulating cell proliferation and apoptosis. Of the two isoforms of SphK (SphK1 and SphK2), little is known about the functions of SphK2. Sodium butyrate (NaBT) has been established as a promising chemotherapeutic agent, but the precise mechanism for its effects is unknown. In this study, we investigated the role of SphK2 in NaBT-induced apoptosis of HCT116 colon cancer cells. The results indicated that following NaBT treatment SphK2 was translocated from the nucleus to the cytoplasm, leading to its accumulation in the cytoplasm; in the meantime, only mild apoptosis occurred. However, downregulation of SphK2 resulted in sensitized apoptosis, and overexpression of SphK2 led to even lighter apoptosis; these strongly indicate an inhibitory role of SphK2 in cell apoptosis induced by NaBT. After knocking down protein kinase D (PKD), another protein reported to be critical in cell proliferation/apoptosis process, by using siRNA, blockage of cytoplasmic accumulation of SphK2 and sensitized apoptosis following NaBT treatment were observed. The present study suggests that PKD and SphK2 may form a mechanism for the resistance of cancer cells to tumor chemotherapies, such as HCT116 colon cancer cells to NaBT, and these two proteins may become molecular targets for designation of new tumor-therapeutic drugs. -- Highlights: ► In the present study sodium butyrate (10 mM) induced mild apoptosis of cancer cells. ► The apoptosis was negatively regulated by cytoplasmic Sphingosine Kinase 2 (SphK2). ► Translocation of SphK2 from nucleus to cytoplasm was mediated by protein kinase D. ► Downregulation of SphK2 or protein kinase D leads to sensitized cell apoptosis.

Transgene Expression of Drosophila melanogaster Nucleoside Kinase Reverses Mitochondrial Thymidine Kinase 2 Deficiency*♦

Science.gov (United States)

Krishnan, Shuba; Zhou, Xiaoshan; Paredes, João A.; Kuiper, Raoul V.; Curbo, Sophie; Karlsson, Anna

2013-01-01

A strategy to reverse the symptoms of thymidine kinase 2 (TK2) deficiency in a mouse model was investigated. The nucleoside kinase from Drosophila melanogaster (Dm-dNK) was expressed in TK2-deficient mice that have been shown to present with a severe phenotype caused by mitochondrial DNA depletion. The Dm-dNK+/− transgenic mice were shown to be able to rescue the TK2-deficient mice. The Dm-dNK+/−TK2−/− mice were normal as judged by growth and behavior during the observation time of 6 months. The Dm-dNK-expressing mice showed a substantial increase in thymidine-phosphorylating activity in investigated tissues. The Dm-dNK expression also resulted in highly elevated dTTP pools. The dTTP pool alterations did not cause specific mitochondrial DNA mutations or deletions when 6-month-old mice were analyzed. The mitochondrial DNA was also detected at normal levels. In conclusion, the Dm-dNK+/−TK2−/− mouse model illustrates how dTMP synthesized in the cell nucleus can compensate for loss of intramitochondrial dTMP synthesis in differentiated tissue. The data presented open new possibilities to treat the severe symptoms of TK2 deficiency. PMID:23288848

Relation between the 2{nu}{beta}{beta} and 0{nu}{beta}{beta} nuclear matrix elements

Energy Technology Data Exchange (ETDEWEB)

Vogel, Petr [Kellogg Radiation Laboratory, Caltech, Pasadena, CA 91125 (United States); Simkovic, Fedor [Department of Nuclear Physics and Biophysics, Comenius University, Mlynska dolina F1, SK-84248 Bratislava (Slovakia)

2011-12-16

A formal relation between the GT part of the nuclear matrix elements M{sub GT}{sup 0{nu}} of 0{nu}{beta}{beta} decay and the closure matrix elements M{sub cl}{sup 2{nu}} of 2{nu}{beta}{beta} decay is established. This relation is based on the integral representation of these quantities in terms of their dependence on the distance r between the two nucleons undergoing transformation. We also discuss the difficulties in determining the correct values of the closure 2{nu}{beta}{beta} decay matrix elements.

Extracellular signal-regulated kinase 2 (ERK-2) mediated phosphorylation regulates nucleo-cytoplasmic shuttling and cell growth control of Ras-associated tumor suppressor protein, RASSF2

International Nuclear Information System (INIS)

Kumari, Gita; Mahalingam, S.

2009-01-01

Ras GTPase controls the normal cell growth through binding with an array of effector molecules, such as Raf and PI3-kinase in a GTP-dependent manner. RASSF2, a member of the Ras association domain family, is known to be involved in the suppression of cell growth and is frequently down-regulated in various tumor tissues by promoter hypermethylation. In the present study, we demonstrate that RASSF2 shuttles between nucleus and cytoplasm by a signal-mediated process and its export from the nucleus is sensitive to leptomycin B. Amino acids between 240 to 260 in the C-terminus of RASSF2 harbor a functional nuclear export signal (NES), which is necessary and sufficient for efficient export of RASSF2 from the nucleus. Substitution of conserved Ile254, Val257 and Leu259 within the minimal NES impaired RASSF2 export from the nucleus. In addition, wild type but not the nuclear export defective RASSF2 mutant interacts with export receptor, CRM-1 and exported from the nucleus. Surprisingly, we observed nucleolar localization for the nuclear export defective mutant suggesting the possibility that RASSF2 may localize in different cellular compartments transiently in a cell cycle dependent manner and the observed nuclear localization for wild type protein may be due to faster export kinetics from the nucleolus. Furthermore, our data suggest that RASSF2 is specifically phosphorylated by MAPK/ERK-2 and the inhibitors of MAPK pathway impair the phosphorylation and subsequently block the export of RASSF2 from the nucleus. These data clearly suggest that ERK-2 mediated phosphorylation plays an important role in regulating the nucleo-cytoplasmic shuttling of RASSF2. Interestingly, nuclear import defective mutant of RASSF2 failed to induce cell cycle arrest at G1/S phase and apoptosis suggesting that RASSF2 regulates cell growth in a nuclear localization dependent manner. Collectively, these data provided evidence for the first time that MAPK/ERK-2 mediated phosphorylation regulates

Extracellular signal-regulated kinase 2 (ERK-2) mediated phosphorylation regulates nucleo-cytoplasmic shuttling and cell growth control of Ras-associated tumor suppressor protein, RASSF2

Energy Technology Data Exchange (ETDEWEB)

Kumari, Gita [Laboratory of Molecular Virology, Centre for DNA Fingerprinting and Diagnostics, Hyderabad 500076 (India); Mahalingam, S., E-mail: mahalingam@iitm.ac.in [Laboratory of Molecular Virology, Centre for DNA Fingerprinting and Diagnostics, Hyderabad 500076 (India); Department of Biotechnology, Laboratory of Molecular Virology and Cell Biology, Indian Institute of Technology-Madras, Chennai 600 036 (India)

2009-10-01

Ras GTPase controls the normal cell growth through binding with an array of effector molecules, such as Raf and PI3-kinase in a GTP-dependent manner. RASSF2, a member of the Ras association domain family, is known to be involved in the suppression of cell growth and is frequently down-regulated in various tumor tissues by promoter hypermethylation. In the present study, we demonstrate that RASSF2 shuttles between nucleus and cytoplasm by a signal-mediated process and its export from the nucleus is sensitive to leptomycin B. Amino acids between 240 to 260 in the C-terminus of RASSF2 harbor a functional nuclear export signal (NES), which is necessary and sufficient for efficient export of RASSF2 from the nucleus. Substitution of conserved Ile254, Val257 and Leu259 within the minimal NES impaired RASSF2 export from the nucleus. In addition, wild type but not the nuclear export defective RASSF2 mutant interacts with export receptor, CRM-1 and exported from the nucleus. Surprisingly, we observed nucleolar localization for the nuclear export defective mutant suggesting the possibility that RASSF2 may localize in different cellular compartments transiently in a cell cycle dependent manner and the observed nuclear localization for wild type protein may be due to faster export kinetics from the nucleolus. Furthermore, our data suggest that RASSF2 is specifically phosphorylated by MAPK/ERK-2 and the inhibitors of MAPK pathway impair the phosphorylation and subsequently block the export of RASSF2 from the nucleus. These data clearly suggest that ERK-2 mediated phosphorylation plays an important role in regulating the nucleo-cytoplasmic shuttling of RASSF2. Interestingly, nuclear import defective mutant of RASSF2 failed to induce cell cycle arrest at G1/S phase and apoptosis suggesting that RASSF2 regulates cell growth in a nuclear localization dependent manner. Collectively, these data provided evidence for the first time that MAPK/ERK-2 mediated phosphorylation regulates

Oncogenic Receptor Tyrosine Kinases Directly Phosphorylate Focal Adhesion Kinase (FAK) as a Resistance Mechanism to FAK-Kinase Inhibitors.

Science.gov (United States)

Marlowe, Timothy A; Lenzo, Felicia L; Figel, Sheila A; Grapes, Abigail T; Cance, William G

2016-12-01

Focal adhesion kinase (FAK) is a major drug target in cancer and current inhibitors targeted to the ATP-binding pocket of the kinase domain have entered clinical trials. However, preliminary results have shown limited single-agent efficacy in patients. Despite these unfavorable data, the molecular mechanisms that drive intrinsic and acquired resistance to FAK-kinase inhibitors are largely unknown. We have demonstrated that receptor tyrosine kinases (RTK) can directly bypass FAK-kinase inhibition in cancer cells through phosphorylation of FAK's critical tyrosine 397 (Y397). We also showed that HER2 forms a direct protein-protein interaction with the FAK-FERM-F1 lobe, promoting direct phosphorylation of Y397. In addition, FAK-kinase inhibition induced two forms of compensatory RTK reprogramming: (i) the rapid phosphorylation and activation of RTK signaling pathways in RTK High cells and (ii) the long-term acquisition of RTKs novel to the parental cell line in RTK Low cells. Finally, HER2 +: cancer cells displayed resistance to FAK-kinase inhibition in 3D growth assays using a HER2 isogenic system and HER2 + cancer cell lines. Our data indicate a novel drug resistance mechanism to FAK-kinase inhibitors whereby HER2 and other RTKs can rescue and maintain FAK activation (pY397) even in the presence of FAK-kinase inhibition. These data may have important ramifications for existing clinical trials of FAK inhibitors and suggest that individual tumor stratification by RTK expression would be important to predict patient response to FAK-kinase inhibitors. Mol Cancer Ther; 15(12); 3028-39. ©2016 AACR. ©2016 American Association for Cancer Research.

Nuclear energy: strategy of public relations

International Nuclear Information System (INIS)

Timell, S.

1981-01-01

A referendum was held in Sweden on 23rd March 1980, stimulated by the Three Mile Island accident in USA, to determine the future nuclear power development policy. The electricity supply background is that in 1980, 65% of power was hydro, 25% nuclear and 10% coal and oil. In terms of total power consumption, the country is heavily dependent on oil, which represents about 75%. The intensive public relations activity previous to the referendum is described, and this involved fact accumulation and assimilation, dissemination through various media, including brochures, displays, films and leaflets. In the political arena three lines developed: (1) (Conservatives); continue nuclear power, building at least 12 reactors, (2) (Social democrats and liberals); similar to (1), but more cautious, with emphasis on energy conservation, (3) (Centre parties and communists); no more nuclear power, and prevention of uranium extraction in Sweden. The voting was (1) 18.9%, (2) 39.1%, (3) 38.7%, (No decision) 3.3%. (G.C.)

A-Raf kinase is a new interacting partner of protein kinase CK2 beta subunit

DEFF Research Database (Denmark)

Boldyreff, B; Issinger, O G

1997-01-01

In a search for protein kinase CK2 beta subunit binding proteins using the two-hybrid system, more than 1000 positive clones were isolated. Beside clones for the alpha' and beta subunit of CK2, there were clones coding for a so far unknown protein, whose partial cDNA sequence was already deposited...

Identifying three-dimensional structures of autophosphorylation complexes in crystals of protein kinases

Science.gov (United States)

Xu, Qifang; Malecka, Kimberly L.; Fink, Lauren; Jordan, E. Joseph; Duffy, Erin; Kolander, Samuel; Peterson, Jeffrey; Dunbrack, Roland L.

2016-01-01

Protein kinase autophosphorylation is a common regulatory mechanism in cell signaling pathways. Crystal structures of several homomeric protein kinase complexes have a serine, threonine, or tyrosine autophosphorylation site of one kinase monomer located in the active site of another monomer, a structural complex that we call an “autophosphorylation complex.” We developed and applied a structural bioinformatics method to identify all such autophosphorylation kinase complexes in X-ray crystallographic structures in the Protein Data Bank (PDB). We identified 15 autophosphorylation complexes in the PDB, of which 5 complexes had not previously been described in the publications describing the crystal structures. These 5 consist of tyrosine residues in the N-terminal juxtamembrane regions of colony stimulating factor 1 receptor (CSF1R, Tyr561) and EPH receptor A2 (EPHA2, Tyr594), tyrosine residues in the activation loops of the SRC kinase family member LCK (Tyr394) and insulin-like growth factor 1 receptor (IGF1R, Tyr1166), and a serine in a nuclear localization signal region of CDC-like kinase 2 (CLK2, Ser142). Mutations in the complex interface may alter autophosphorylation activity and contribute to disease; therefore we mutated residues in the autophosphorylation complex interface of LCK and found that two mutations impaired autophosphorylation (T445V and N446A) and mutation of Pro447 to Ala, Gly, or Leu increased autophosphorylation. The identified autophosphorylation sites are conserved in many kinases, suggesting that, by homology, these complexes may provide insight into autophosphorylation complex interfaces of kinases that are relevant drug targets. PMID:26628682

Molecular Mechanism of Selectivity among G Protein-Coupled Receptor Kinase 2 Inhibitors

Energy Technology Data Exchange (ETDEWEB)

Thal, David M.; Yeow, Raymond Y.; Schoenau, Christian; Huber, Jochen; Tesmer, John J.G. (Sanofi); (Michigan)

2012-07-11

G protein-coupled receptors (GPCRs) are key regulators of cell physiology and control processes ranging from glucose homeostasis to contractility of the heart. A major mechanism for the desensitization of activated GPCRs is their phosphorylation by GPCR kinases (GRKs). Overexpression of GRK2 is strongly linked to heart failure, and GRK2 has long been considered a pharmaceutical target for the treatment of cardiovascular disease. Several lead compounds developed by Takeda Pharmaceuticals show high selectivity for GRK2 and therapeutic potential for the treatment of heart failure. To understand how these drugs achieve their selectivity, we determined crystal structures of the bovine GRK2-G{beta}{gamma} complex in the presence of two of these inhibitors. Comparison with the apoGRK2-G{beta}{gamma} structure demonstrates that the compounds bind in the kinase active site in a manner similar to that of the AGC kinase inhibitor balanol. Both balanol and the Takeda compounds induce a slight closure of the kinase domain, the degree of which correlates with the potencies of the inhibitors. Based on our crystal structures and homology modeling, we identified five amino acids surrounding the inhibitor binding site that we hypothesized could contribute to inhibitor selectivity. However, our results indicate that these residues are not major determinants of selectivity among GRK subfamilies. Rather, selectivity is achieved by the stabilization of a unique inactive conformation of the GRK2 kinase domain.

A role for Pyk2 and Src in linking G-protein-coupled receptors with MAP kinase activation.

Science.gov (United States)

Dikic, I; Tokiwa, G; Lev, S; Courtneidge, S A; Schlessinger, J

1996-10-10

The mechanisms by which mitogenic G-protein-coupled receptors activate the MAP kinase signalling pathway are poorly understood. Candidate protein tyrosine kinases that link G-protein-coupled receptors with MAP kinase include Src family kinases, the epidermal growth factor receptor, Lyn and Syk. Here we show that lysophosphatidic acid (LPA) and bradykinin induce tyrosine phosphorylation of Pyk2 and complex formation between Pyk2 and activated Src. Moreover, tyrosine phosphorylation of Pyk2 leads to binding of the SH2 domain of Src to tyrosine 402 of Pyk2 and activation of Src. Transient overexpression of a dominant interfering mutant of Pyk2 or the protein tyrosine kinase Csk reduces LPA- or bradykinin-induced activation of MAP kinase. LPA- or bradykinin-induced MAP kinase activation was also inhibited by overexpression of dominant interfering mutants of Grb2 and Sos. We propose that Pyk2 acts with Src to link Gi- and Gq-coupled receptors with Grb2 and Sos to activate the MAP kinase signalling pathway in PC12 cells.

Protein kinase Cη activates NF-κB in response to camptothecin-induced DNA damage

International Nuclear Information System (INIS)

Raveh-Amit, Hadas; Hai, Naama; Rotem-Dai, Noa; Shahaf, Galit; Gopas, Jacob; Livneh, Etta

2011-01-01

Highlights: → Protein kinase C-eta (PKCη) is an upstream regulator of the NF-κB signaling pathway. → PKCη activates NF-κB in non-stressed conditions and in response to DNA damage. → PKCη regulates NF-κB by activating IκB kinase (IKK) and inducing IκB degradation. -- Abstract: The nuclear factor κB (NF-κB) family of transcription factors participates in the regulation of genes involved in innate- and adaptive-immune responses, cell death and inflammation. The involvement of the Protein kinase C (PKC) family in the regulation of NF-κB in inflammation and immune-related signaling has been extensively studied. However, not much is known on the role of PKC in NF-κB regulation in response to DNA damage. Here we demonstrate for the first time that PKC-eta (PKCη) regulates NF-κB upstream signaling by activating the IκB kinase (IKK) and the degradation of IκB. Furthermore, PKCη enhances the nuclear translocation and transactivation of NF-κB under non-stressed conditions and in response to the anticancer drug camptothecin. We and others have previously shown that PKCη confers protection against DNA damage-induced apoptosis. Our present study suggests that PKCη is involved in NF-κB signaling leading to drug resistance.

Phosphorylation of Dgk1 Diacylglycerol Kinase by Casein Kinase II Regulates Phosphatidic Acid Production in Saccharomyces cerevisiae.

Science.gov (United States)

Qiu, Yixuan; Hassaninasab, Azam; Han, Gil-Soo; Carman, George M

2016-12-16

In the yeast Saccharomyces cerevisiae, Dgk1 diacylglycerol (DAG) kinase catalyzes the CTP-dependent phosphorylation of DAG to form phosphatidic acid (PA). The enzyme in conjunction with Pah1 PA phosphatase controls the levels of PA and DAG for the synthesis of triacylglycerol and membrane phospholipids, the growth of the nuclear/endoplasmic reticulum membrane, and the formation of lipid droplets. Little is known about how DAG kinase activity is regulated by posttranslational modification. In this work, we examined the phosphorylation of Dgk1 DAG kinase by casein kinase II (CKII). When phosphate groups were globally reduced using nonspecific alkaline phosphatase, Triton X-100-solubilized membranes from DGK1-overexpressing cells showed a 7.7-fold reduction in DAG kinase activity; the reduced enzyme activity could be increased 5.5-fold by treatment with CKII. Dgk1(1-77) expressed heterologously in Escherichia coli was phosphorylated by CKII on a serine residue, and its phosphorylation was dependent on time as well as on the concentrations of CKII, ATP, and Dgk1(1-77). We used site-specific mutagenesis, coupled with phosphorylation analysis and phosphopeptide mapping, to identify Ser-45 and Ser-46 of Dgk1 as the CKII target sites, with Ser-46 being the major phosphorylation site. In vivo, the S46A and S45A/S46A mutations of Dgk1 abolished the stationary phase-dependent stimulation of DAG kinase activity. In addition, the phosphorylation-deficient mutations decreased Dgk1 function in PA production and in eliciting pah1Δ phenotypes, such as the expansion of the nuclear/endoplasmic reticulum membrane, reduced lipid droplet formation, and temperature sensitivity. This work demonstrates that the CKII-mediated phosphorylation of Dgk1 regulates its function in the production of PA. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Phosphorylation of Dgk1 Diacylglycerol Kinase by Casein Kinase II Regulates Phosphatidic Acid Production in Saccharomyces cerevisiae*

Science.gov (United States)

Qiu, Yixuan; Hassaninasab, Azam; Han, Gil-Soo; Carman, George M.

2016-01-01

In the yeast Saccharomyces cerevisiae, Dgk1 diacylglycerol (DAG) kinase catalyzes the CTP-dependent phosphorylation of DAG to form phosphatidic acid (PA). The enzyme in conjunction with Pah1 PA phosphatase controls the levels of PA and DAG for the synthesis of triacylglycerol and membrane phospholipids, the growth of the nuclear/endoplasmic reticulum membrane, and the formation of lipid droplets. Little is known about how DAG kinase activity is regulated by posttranslational modification. In this work, we examined the phosphorylation of Dgk1 DAG kinase by casein kinase II (CKII). When phosphate groups were globally reduced using nonspecific alkaline phosphatase, Triton X-100-solubilized membranes from DGK1-overexpressing cells showed a 7.7-fold reduction in DAG kinase activity; the reduced enzyme activity could be increased 5.5-fold by treatment with CKII. Dgk1(1–77) expressed heterologously in Escherichia coli was phosphorylated by CKII on a serine residue, and its phosphorylation was dependent on time as well as on the concentrations of CKII, ATP, and Dgk1(1–77). We used site-specific mutagenesis, coupled with phosphorylation analysis and phosphopeptide mapping, to identify Ser-45 and Ser-46 of Dgk1 as the CKII target sites, with Ser-46 being the major phosphorylation site. In vivo, the S46A and S45A/S46A mutations of Dgk1 abolished the stationary phase-dependent stimulation of DAG kinase activity. In addition, the phosphorylation-deficient mutations decreased Dgk1 function in PA production and in eliciting pah1Δ phenotypes, such as the expansion of the nuclear/endoplasmic reticulum membrane, reduced lipid droplet formation, and temperature sensitivity. This work demonstrates that the CKII-mediated phosphorylation of Dgk1 regulates its function in the production of PA. PMID:27834677

eIF2α Kinases Control Chalone Production in Dictyostelium discoideum ▿

Science.gov (United States)

Bowman, Robert L.; Xiong, Yanhua; Kirsten, Janet H.; Singleton, Charles K.

2011-01-01

Growing Dictyostelium cells secrete CfaD and AprA, two proteins that have been characterized as chalones. They exist within a high-molecular-weight complex that reversibly inhibits cell proliferation, but not growth, via cell surface receptors and a signaling pathway that includes G proteins. How the production of these two proteins is regulated is unknown. Dictyostelium cells possess three GCN2-type eukaryotic initiation factor 2 α subunit (eIF2α) kinases, proteins that phosphorylate the translational initiation factor eIF2α and possess a tRNA binding domain involved in their regulation. The Dictyostelium kinases have been shown to function during development in regulating several processes. We show here that expression of an unregulated, activated kinase domain greatly inhibits cell proliferation. The inhibitory effect on proliferation is not due to a general inhibition of translation. Instead, it is due to enhanced production of a secreted factor(s). Indeed, extracellular CfaD and AprA proteins, but not their mRNAs, are overproduced in cells expressing the activated kinase domain. The inhibition of proliferation is not seen when the activated kinase domain is expressed in cells lacking CfaD or AprA or in cells that contain a nonphosphorylatable eIF2α. We conclude that production of the chalones CfaD and AprA is translationally regulated by eIF2α phosphorylation. Both proteins are upregulated at the culmination of development, and this enhanced production is lacking in a strain that possesses a nonphosphorylatable eIF2α. PMID:21278229

Janus-kinase-2 relates directly to portal hypertension and to complications in rodent and human cirrhosis.

Science.gov (United States)

Klein, Sabine; Rick, Johanna; Lehmann, Jennifer; Schierwagen, Robert; Schierwagen, Irela Gretchen; Verbeke, Len; Hittatiya, Kanishka; Uschner, Frank Erhard; Manekeller, Steffen; Strassburg, Christian P; Wagner, Kay-Uwe; Sayeski, Peter P; Wolf, Dominik; Laleman, Wim; Sauerbruch, Tilman; Trebicka, Jonel

2017-01-01

Angiotensin II (AngII) activates via angiotensin-II-type-I receptor (AT1R) Janus-kinase-2 (JAK2)/Arhgef1 pathway and subsequently RHOA/Rho-kinase (ROCK), which induces experimental and probably human liver fibrosis. This study investigated the relationship of JAK2 to experimental and human portal hypertension. The mRNA and protein levels of JAK2/ARHGEF1 signalling components were analysed in 49 human liver samples and correlated with clinical parameters of portal hypertension in these patients. Correspondingly, liver fibrosis (bile duct ligation (BDL), carbon tetrachloride (CCl 4 )) was induced in floxed-Jak2 knock-out mice with SM22-promotor (SM22 Cre+ -Jak2 f/f ). Transcription and contraction of primary myofibroblasts from healthy and fibrotic mice and rats were analysed. In two different cirrhosis models (BDL, CCl 4 ) in rats, the acute haemodynamic effect of the JAK2 inhibitor AG490 was assessed using microsphere technique and isolated liver perfusion experiments. Hepatic transcription of JAK2/ARHGEF1 pathway components was upregulated in liver cirrhosis dependent on aetiology, severity and complications of human liver cirrhosis (Model for End-stage Liver disease (MELD) score, Child score as well as ascites, high-risk varices, spontaneous bacterial peritonitis). SM22 Cre+ - Jak2 f/f mice lacking Jak2 developed less fibrosis and lower portal pressure (PP) than SM22 Cre- -Jak2 f/f upon fibrosis induction. Myofibroblasts from SM22 Cre+ -Jak2 f/f mice expressed less collagen and profibrotic markers upon activation. AG490 relaxed activated hepatic stellate cells in vitro. In cirrhotic rats, AG490 decreased hepatic vascular resistance and consequently the PP in vivo and in situ. Hepatic JAK2/ARHGEF1/ROCK expression is associated with portal hypertension and decompensation in human cirrhosis. The deletion of Jak2 in myofibroblasts attenuated experimental fibrosis and acute inhibition of JAK2 decreased PP. Thus, JAK2 inhibitors, already in clinical use for other

Extracellular signal-regulated kinases 1/2 as regulators of cardiac hypertrophy

Directory of Open Access Journals (Sweden)

Michael eMutlak

2015-07-01

Full Text Available Cardiac hypertrophy results from increased mechanical load on the heart and through the actions of local and systemic neuro-humoral factors, cytokines and growth factors. These mechanical and neuroendocrine effectors act through stretch, G protein-coupled receptors and tyrosine kinases to induce the activation of a myriad of intracellular signaling pathways including the extracellular signal-regulated kinases 1/2 (ERK1/2. Since most stimuli that provoke myocardial hypertrophy also elicit an acute phosphorylation of the threonine-glutamate-tyrosine (TEY motif within the activation loops of ERK1 and ERK2 kinases, resulting in their activation, ERKs have long been considered promotors of cardiac hypertrophy. Several mouse models were generated in order to directly understand the causal role of ERK1/2 activation in the heart. These models include direct manipulation of ERK1/2 such as overexpression, mutagenesis or knockout models, manipulations of upstream kinases such as MEK1 and manipulations of the phosphatases that depohosphorylate ERK1/2 such as DUSP6. The emerging understanding from these studies, as will be discussed here, is more complex than originally considered. While there is little doubt that ERK1/2 activation or the lack of it modulates the hypertrophic process or the type of hypertrophy that develops, it appears that not all ERK1/2 activation events are the same. While much has been learned, some questions remain regarding the exact role of ERK1/2 in the heart, the upstream events that result in ERK1/2 activation and the downstream effector in hypertrophy.

Retrospective natural history of thymidine kinase 2 deficiency.

Science.gov (United States)

Garone, Caterina; Taylor, Robert W; Nascimento, Andrés; Poulton, Joanna; Fratter, Carl; Domínguez-González, Cristina; Evans, Julie C; Loos, Mariana; Isohanni, Pirjo; Suomalainen, Anu; Ram, Dipak; Hughes, M Imelda; McFarland, Robert; Barca, Emanuele; Lopez Gomez, Carlos; Jayawant, Sandeep; Thomas, Neil D; Manzur, Adnan Y; Kleinsteuber, Karin; Martin, Miguel A; Kerr, Timothy; Gorman, Grainne S; Sommerville, Ewen W; Chinnery, Patrick F; Hofer, Monika; Karch, Christoph; Ralph, Jeffrey; Cámara, Yolanda; Madruga-Garrido, Marcos; Domínguez-Carral, Jana; Ortez, Carlos; Emperador, Sonia; Montoya, Julio; Chakrapani, Anupam; Kriger, Joshua F; Schoenaker, Robert; Levin, Bruce; Thompson, John L P; Long, Yuelin; Rahman, Shamima; Donati, Maria Alice; DiMauro, Salvatore; Hirano, Michio

2018-03-30

Thymine kinase 2 (TK2) is a mitochondrial matrix protein encoded in nuclear DNA and phosphorylates the pyrimidine nucleosides: thymidine and deoxycytidine. Autosomal recessive TK2 mutations cause a spectrum of disease from infantile onset to adult onset manifesting primarily as myopathy. To perform a retrospective natural history study of a large cohort of patients with TK2 deficiency. The study was conducted by 42 investigators across 31 academic medical centres. We identified 92 patients with genetically confirmed diagnoses of TK2 deficiency: 67 from literature review and 25 unreported cases. Based on clinical and molecular genetics findings, we recognised three phenotypes with divergent survival: (1) infantile-onset myopathy (42.4%) with severe mitochondrial DNA (mtDNA) depletion, frequent neurological involvement and rapid progression to early mortality (median post-onset survival (POS) 1.00, CI 0.58 to 2.33 years); (2) childhood-onset myopathy (40.2%) with mtDNA depletion, moderate-to-severe progression of generalised weakness and median POS at least 13 years; and (3) late-onset myopathy (17.4%) with mild limb weakness at onset and slow progression to respiratory insufficiency with median POS of 23 years. Ophthalmoparesis and facial weakness are frequent in adults. Muscle biopsies show multiple mtDNA deletions often with mtDNA depletion. In TK2 deficiency, age at onset, rate of weakness progression and POS are important variables that define three clinical subtypes. Nervous system involvement often complicates the clinical course of the infantile-onset form while extraocular muscle and facial involvement are characteristic of the late-onset form. Our observations provide essential information for planning future clinical trials in this disorder. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Mechanism of activation of glycogen phosphorylase by fructose in the liver. Stimulation of phosphorylase kinase related to the consumption of adenosine triphosphate.

Science.gov (United States)

Van de Werve, G; Hers, H G

1979-01-15

1. A dose-dependent activation of phosphorylase and consumption of ATP was observed in isolated hepatocytes incubated in the presence of fructose; histone kinase and phosphorylase kinase activities were unchanged at doses of this sugar that were fully effective on phosphorylase. The activation of phosphorylase by fructose was also observed in cells incubated in a Ca2+-free medium as well as in the livers of rats in vivo. 2. In a liver high-speed supernatant, fructose, tagatose and sorbose stimulated the activity of phosphorylase kinase; this effect was dependent on the presence of K+ ions, which are required for the activity of fructokinase; it was accompanied by the transformation of ATP into ADP. In the presence of hexokinase, glucose also stimulated phosphorylase kinase, both in an Na+ or a K+ medium. 3. The activities of partially purified muscle or liver phosphorylase kinase were unchanged in the presence of fructose. 4. Some properties of liver phosphorylase kinase are described, including a high molecular weight and an inhibition at ATP/Mg ratios above 0.5, as well as an effect of ATP concentration on the hysteretic behaviour of this enzyme. 5. The effect of fructose on the activation of phosphorylase is discussed in relation to the comsumption of ATP.

Catalytic properties of inositol trisphosphate kinase: activation by Ca2+ and calmodulin

International Nuclear Information System (INIS)

Ryu, S.H.; Lee, S.Y.; Lee, K.Y.; Rhee, S.G.

1987-01-01

Inositol 1,4,5-triphosphate (Ins-1,4,5-P 3 ) is an important second-messenger molecule that mobilizes Ca 2+ from intracellular stores in response to the occupancy of receptor by various Ca 2+ -mobilizing agonists. The fate of Ins-1,4,5-P 3 is determined by two enzymes, a 3-kinase and a 5-phosphomonoesterase. The first enzyme converts Ins-1,4,5-P 3 to Ins-1,3,4,5-P 4 , whereas the latter forms Ins-1,4-P 2 . Recent studies suggest that Ins-1,3,4,5-P 4 might modulate the entry of Ca 2+ from an extracellular source. In the current report, the authors describe the partial purification of the 3-kinase from the cytosolic fraction of bovine brain and studies of its catalytic properties. They found that the 3-kinase activity is significantly activated by the Ca 2+ /calmodulin complex. Therefore, they propose that Ca 2+ mobilized from endoplasmic reticulum by the action of Ins-1,4,5-P 3 forms a complex with calmodulin, and that the Ca 2+ /calmodulin complex stimulates the conversion of Ins-1,4,5-P 3 , and intracellular Ca 2+ mobilizer, to Ins-1,3,4,5-P 4 , an extracellular Ca 2+ mobilizer. A rapid assay method for the 3-kinase was developed that is based on the separation of [3- 32 P]Ins-1,3,4,5-P 4 and [γ- 32 P]ATP by thin-layer chromatography. Using this new assay method, they evaluated kinetic parameters (K/sub m/ for ATP = 40 μM, K/sub m/ for Ins-1,4,5-P 3 = 0.7 μM, K/sub i/ for ADP = 12 μM) and divalent cation specificity (Mg 2+ > > Mn 2+ > Ca 2+ ) for the 3-kinase

Fluorescent peptide biosensor for probing the relative abundance of cyclin-dependent kinases in living cells.

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Laetitia Kurzawa

Full Text Available Cyclin-dependant kinases play a central role in coordinating cell growth and division, and in sustaining proliferation of cancer cells, thereby constituting attractive pharmacological targets. However, there are no direct means of assessing their relative abundance in living cells, current approaches being limited to antigenic and proteomic analysis of fixed cells. In order to probe the relative abundance of these kinases directly in living cells, we have developed a fluorescent peptide biosensor with biligand affinity for CDKs and cyclins in vitro, that retains endogenous CDK/cyclin complexes from cell extracts, and that bears an environmentally-sensitive probe, whose fluorescence increases in a sensitive fashion upon recognition of its targets. CDKSENS was introduced into living cells, through complexation with the cell-penetrating carrier CADY2 and applied to assess the relative abundance of CDK/Cyclins through fluorescence imaging and ratiometric quantification. This peptide biosensor technology affords direct and sensitive readout of CDK/cyclin complex levels, and reports on differences in complex formation when tampering with a single CDK or cyclin. CDKSENS further allows for detection of differences between different healthy and cancer cell lines, thereby enabling to distinguish cells that express high levels of these heterodimeric kinases, from cells that present decreased or defective assemblies. This fluorescent biosensor technology provides information on the overall status of CDK/Cyclin complexes which cannot be obtained through antigenic detection of individual subunits, in a non-invasive fashion which does not require cell fixation or extraction procedures. As such it provides promising perspectives for monitoring the response to therapeutics that affect CDK/Cyclin abundance, for cell-based drug discovery strategies and fluorescence-based cancer diagnostics.

Safety-evaluation report related to operation of McGuire Nuclear Station, Units 1 and 2. Docket Nos. 50-369 and 50-370

International Nuclear Information System (INIS)

1983-05-01

This report supplements the Safety Evaluation Report Related to the Operation of McGuire Nuclear Station, Units 1 and 2 (SER (NUREG-0422)) issued in March 1978 by the Office of Nuclear Reactor Regulation of the US Nuclear Regulatory Commission with respect to the application filed by Duke Power Company, as applicant and owner, for licenses to operate the McGuire Nuclear Station, Units 1 and 2 (Docket Nos. 50-369 and 50-370). The facility is located in Mecklenburg County, North Carolina, about 17 mi north-northwest of Charlotte, North Carolina. This supplement provides information related to issuance of a full-power authorization for Unit 2. The staff concludes that the McGuire Nuclear Station can be operated by the licensee without endangering the health and safety of the public

The Hsk1(Cdc7) replication kinase regulates origin efficiency.

Science.gov (United States)

Patel, Prasanta K; Kommajosyula, Naveen; Rosebrock, Adam; Bensimon, Aaron; Leatherwood, Janet; Bechhoefer, John; Rhind, Nicholas

2008-12-01

Origins of DNA replication are generally inefficient, with most firing in fewer than half of cell cycles. However, neither the mechanism nor the importance of the regulation of origin efficiency is clear. In fission yeast, origin firing is stochastic, leading us to hypothesize that origin inefficiency and stochasticity are the result of a diffusible, rate-limiting activator. We show that the Hsk1-Dfp1 replication kinase (the fission yeast Cdc7-Dbf4 homologue) plays such a role. Increasing or decreasing Hsk1-Dfp1 levels correspondingly increases or decreases origin efficiency. Furthermore, tethering Hsk1-Dfp1 near an origin increases the efficiency of that origin, suggesting that the effective local concentration of Hsk1-Dfp1 regulates origin firing. Using photobleaching, we show that Hsk1-Dfp1 is freely diffusible in the nucleus. These results support a model in which the accessibility of replication origins to Hsk1-Dfp1 regulates origin efficiency and provides a potential mechanistic link between chromatin structure and replication timing. By manipulating Hsk1-Dfp1 levels, we show that increasing or decreasing origin firing rates leads to an increase in genomic instability, demonstrating the biological importance of appropriate origin efficiency.

The Hsk1(Cdc7) Replication Kinase Regulates Origin Efficiency

Science.gov (United States)

Patel, Prasanta K.; Kommajosyula, Naveen; Rosebrock, Adam; Bensimon, Aaron; Leatherwood, Janet; Bechhoefer, John

2008-01-01

Origins of DNA replication are generally inefficient, with most firing in fewer than half of cell cycles. However, neither the mechanism nor the importance of the regulation of origin efficiency is clear. In fission yeast, origin firing is stochastic, leading us to hypothesize that origin inefficiency and stochasticity are the result of a diffusible, rate-limiting activator. We show that the Hsk1-Dfp1 replication kinase (the fission yeast Cdc7-Dbf4 homologue) plays such a role. Increasing or decreasing Hsk1-Dfp1 levels correspondingly increases or decreases origin efficiency. Furthermore, tethering Hsk1-Dfp1 near an origin increases the efficiency of that origin, suggesting that the effective local concentration of Hsk1-Dfp1 regulates origin firing. Using photobleaching, we show that Hsk1-Dfp1 is freely diffusible in the nucleus. These results support a model in which the accessibility of replication origins to Hsk1-Dfp1 regulates origin efficiency and provides a potential mechanistic link between chromatin structure and replication timing. By manipulating Hsk1-Dfp1 levels, we show that increasing or decreasing origin firing rates leads to an increase in genomic instability, demonstrating the biological importance of appropriate origin efficiency. PMID:18799612

Crystal structure of human cyclin-dependent kinase-2 complex with MK2 inhibitor TEI-I01800: insight into the selectivity

Energy Technology Data Exchange (ETDEWEB)

Fujino, Aiko; Fukushima, Kei; Kubota, Takaharu; Kosugi, Tomomi; Takimoto-Kamimura, Midori, E-mail: m.kamimura@teijin.co.jp [Teijin Pharma Limited, 4-3-2 Asahigaoka, Hino-shi, Tokyo 191-8512 (Japan)

2013-11-01

The Gly-rich loop of cyclin-dependent kinase 2 (CDK2) bound to TEI-I01800 as an MK2 specific inhibitor forms a β-sheet which is a common structure in CDK2–ligand complexes. Here, the reason why TEI-I01800 does not become a strong inhibitor against CDK2 based on the conformation of TEI-I01800 is presented. Mitogen-activated protein kinase-activated protein kinase 2 (MK2 or MAPKAP-K2) is a Ser/Thr kinase from the p38 mitogen-activated protein kinase signalling pathway and plays an important role in inflammatory diseases. The crystal structure of the MK2–TEI-I01800 complex has been reported; its Gly-rich loop was found to form an α-helix, not a β-sheet as has been observed for other Ser/Thr kinases. TEI-I01800 is 177-fold selective against MK2 compared with CDK2; in order to understand the inhibitory mechanism of TEI-I01800, the cyclin-dependent kinase 2 (CDK2) complex structure with TEI-I01800 was determined at 2.0 Å resolution. Interestingly, the Gly-rich loop of CDK2 formed a β-sheet that was different from that of MK2. In MK2, TEI-I01800 changed the secondary structure of the Gly-rich loop from a β-sheet to an α-helix by collision between Leu70 and a p-ethoxyphenyl group at the 7-position and bound to MK2. However, for CDK2, TEI-I01800 bound to CDK2 without this structural change and lost the interaction with the substituent at the 7-position. In summary, the results of this study suggest that the reason for the selectivity of TEI-I01800 is the favourable conformation of TEI-I01800 itself, making it suitable for binding to the α-form MK2.

Purification, crystallization and preliminary crystallographic analysis of the SH2 domain of IL-2-inducible T-cell kinase

International Nuclear Information System (INIS)

Joseph, Raji E.; Ginder, Nathaniel D.; Hoy, Julie A.; Nix, Jay C.; Honzatko, Richard B.; Andreotti, Amy H.

2011-01-01

Crystallization conditions are described for the cis- and trans-imide bond-containing SH2 domain of IL-2-inducible T-cell kinase. Proline is a unique amino acid owing to the relatively small energy difference between the cis and trans conformations of its peptide bond. The X–Pro imide bond readily undergoes cis–trans isomerization in the context of short peptides as well as some proteins. However, the direct detection of cis–trans proline isomerization in folded proteins is technically challenging. NMR spectroscopy is well suited to the direct detection of proline isomerization in folded proteins. It is less clear how well X-ray crystallography can reveal this conformational exchange event in folded proteins. Conformational heterogeneity owing to cis–trans proline isomerization in the Src homology 2 (SH2) domain of the IL-2-inducible T-cell kinase (ITK) has been extensively characterized by NMR. Using the ITK SH2 domain as a test system, an attempt was made to determine whether proline isomerization could be detected in a crystal structure of the ITK SH2 domain. As a first step towards this goal, the purification, crystallization and preliminary characterization of the ITK SH2 domain are described

Contractions activate hormone-sensitive lipase in rat muscle by protein kinase C and mitogen-activated protein kinase

DEFF Research Database (Denmark)

Donsmark, Morten; Langfort, Jozef; Holm, Cecilia

2003-01-01

and contractions. Adrenaline acts via cAMP-dependent protein kinase (PKA). The signalling mediating the effect of contractions is unknown and was explored in this study. Incubated soleus muscles from 70 g male rats were electrically stimulated to perform repeated tetanic contractions for 5 min. The contraction......Intramuscular triacylglycerol is an important energy store and is also related to insulin resistance. The mobilization of fatty acids from this pool is probably regulated by hormone-sensitive lipase (HSL), which has recently been shown to exist in muscle and to be activated by both adrenaline......-induced activation of HSL was abolished by the protein kinase C (PKC) inhibitors bisindolylmaleimide I and calphostin C and reduced 50% by the mitogen-activated protein kinase kinase (MEK) inhibitor U0126, which also completely blocked extracellular signal-regulated kinase (ERK) 1 and 2 phosphorylation. None...

Inhibitors of JAK-family kinases: an update on the patent literature 2013-2015, part 2.

Science.gov (United States)

Kettle, Jason G; Åstrand, Annika; Catley, Matthew; Grimster, Neil P; Nilsson, Magnus; Su, Qibin; Woessner, Richard

2017-02-01

Janus kinases (JAKs) are a family of four enzymes; JAK1, JAK2, JAK3 and tyrosine kinase 2 (TYK2) that are critical in cytokine signalling and are strongly linked to both cancer and inflammatory diseases. There are currently two launched JAK inhibitors for the treatment of human conditions: tofacitinib for Rheumatoid arthritis (RA) and ruxolitinib for myeloproliferative neoplasms including intermediate or high risk myelofibrosis and polycythemia vera. Areas covered: This review covers patents claiming activity against one or more JAK family members in the period 2013-2015 inclusive, and covers 95 patents from 42 applicants, split over two parts. The authors have ordered recent patents according to the primary applicant's name, with part 2 covering J through Z. Expert opinion: Inhibition of JAK-family kinases is an area of growing interest, catalysed by the maturity of data on marketed inhibitors ruxolitinib and tofacitinib in late stage clinical trials. Many applicants are pursuing traditional fast-follower strategies around these inhibitors, with a range of chemical strategies adopted. The challenge will be to show sufficient differentiation to the originator compounds, since dose limiting toxicities with such agents appear to be on target and mechanism-related and also considering that such agents may be available as generic compounds by the time follower agents reach market.

β-Catenin is required for intrinsic but not extrinsic BCR-ABL1 kinase-independent resistance to tyrosine kinase inhibitors in chronic myeloid leukemia.

Science.gov (United States)

Eiring, A M; Khorashad, J S; Anderson, D J; Yu, F; Redwine, H M; Mason, C C; Reynolds, K R; Clair, P M; Gantz, K C; Zhang, T Y; Pomicter, A D; Kraft, I L; Bowler, A D; Johnson, K; Partlin, M Mac; O'Hare, T; Deininger, M W

2015-12-01

Activation of nuclear β-catenin and expression of its transcriptional targets promotes chronic myeloid leukemia (CML) progression, tyrosine kinase inhibitor (TKI) resistance, and leukemic stem cell self-renewal. We report that nuclear β-catenin has a role in leukemia cell-intrinsic but not -extrinsic BCR-ABL1 kinase-independent TKI resistance. Upon imatinib inhibition of BCR-ABL1 kinase activity, β-catenin expression was maintained in intrinsically resistant cells grown in suspension culture and sensitive cells cultured in direct contact (DC) with bone marrow (BM) stromal cells. Thus, TKI resistance uncouples β-catenin expression from BCR-ABL1 kinase activity. In β-catenin reporter assays, intrinsically resistant cells showed increased transcriptional activity versus parental TKI-sensitive controls, and this was associated with restored expression of β-catenin target genes. In contrast, DC with BM stromal cells promoted TKI resistance, but had little effects on Lef/Tcf reporter activity and no consistent effects on cytoplasmic β-catenin levels, arguing against a role for β-catenin in extrinsic TKI resistance. N-cadherin or H-cadherin blocking antibodies abrogated DC-based resistance despite increasing Lef/Tcf reporter activity, suggesting that factors other than β-catenin contribute to extrinsic, BM-derived TKI resistance. Our data indicate that, while nuclear β-catenin enhances survival of intrinsically TKI-resistant CML progenitors, it is not required for extrinsic resistance mediated by the BM microenvironment.

Downstream of tyrosine kinase/docking protein 6, as a novel substrate of tropomyosin-related kinase C receptor, is involved in neurotrophin 3-mediated neurite outgrowth in mouse cortex neurons

Directory of Open Access Journals (Sweden)

Yuan Jian

2010-06-01

Full Text Available Abstract Background The downstream of tyrosine kinase/docking protein (Dok adaptor protein family has seven members, Dok1 to Dok7, that act as substrates of multiple receptor tyrosine kinase and non-receptor tyrosine kinase. The tropomyosin-related kinase (Trk receptor family, which has three members (TrkA, TrkB and TrkC, are receptor tyrosine kinases that play pivotal roles in many stages of nervous system development, such as differentiation, migration, axon and dendrite projection and neuron patterning. Upon related neurotrophin growth factor stimulation, dimerisation and autophosphorylation of Trk receptors can occur, recruiting adaptor proteins to mediate signal transduction. Results In this report, by using yeast two-hybrid assays, glutathione S-transferase (GST precipitation assays and coimmunoprecipitation (Co-IP experiments, we demonstrate that Dok6 selectively binds to the NPQY motif of TrkC through its phosphotyrosine-binding (PTB domain in a kinase activity-dependent manner. We further confirmed their interaction by coimmunoprecipitation and colocalisation in E18.5 mouse cortex neurons, which provided more in vivo evidence. Next, we demonstrated that Dok6 is involved in neurite outgrowth in mouse cortex neurons via the RNAi method. Knockdown of Dok6 decreased neurite outgrowth in cortical neurons upon neurotrophin 3 (NT-3 stimulation. Conclusions We conclude that Dok6 interacts with the NPQY motif of the TrkC receptor through its PTB domain in a kinase activity-dependent manner, and works as a novel substrate of the TrkC receptor involved in NT-3-mediated neurite outgrowth in mouse cortex neurons.

A chimeric cyclic interferon-α2b peptide induces apoptosis by sequential activation of phosphatidylinositol 3-kinase, protein kinase Cδ and p38 MAP kinase.

Science.gov (United States)

Blank, V C; Bertucci, L; Furmento, V A; Peña, C; Marino, V J; Roguin, L P

2013-06-10

We have previously demonstrated that tyrosine phosphorylation of STAT1/3 and p38 mitogen-activated protein kinase (p38 MAPK) activation are involved in the apoptotic response triggered by a chimeric cyclic peptide of the interferon-α2b (IFN-α2b) in WISH cells. Since the peptide also induced serine phosphorylation of STAT proteins, in the present study we examined the kinase involved in serine STAT1 phosphorylation and the signaling effectors acting upstream such activation. We first found that p38 MAPK is involved in serine STAT1 phosphorylation, since a reduction of phophoserine-STAT1 levels was evident after incubating WISH cells with cyclic peptide in the presence of a p38 pharmacological inhibitor or a dominant-negative p38 mutant. Next, we demonstrated that the peptide induced activation of protein kinase Cδ (PKCδ). Based on this finding, the role of this kinase was then evaluated. After incubating WISH cells with a PKCδ inhibitor or after decreasing PKCδ expression levels by RNA interference, both peptide-induced serine STAT1 and p38 phosphorylation levels were significantly decreased, indicating that PKCδ functions as an upstream regulator of p38. We also showed that PKCδ and p38 activation stimulated by the peptide was inhibited by a specific pharmacological inhibitor of phosphatidylinositol 3-kinase (PI3K) or by a dominant-negative p85 PI3K-regulatory subunit, suggesting that PI3K is upstream in the signaling cascade. In addition, the role of PI3K and PKCδ in cyclic peptide-induced apoptosis was examined. Both signaling effectors were found to regulate the antiproliferative activity and the apoptotic response triggered by the cyclic peptide in WISH cells. In conclusion, we herein demonstrated that STAT1 serine phosphorylation is mediated by the sequential activation of PI3K, PKCδ and p38 MAPK. This signaling cascade contributes to the antitumor effect induced by the chimeric IFN-α2b cyclic peptide in WISH cells. Copyright © 2013 Elsevier Inc

Retained sensitivity to cytotoxic pyrimidine nucleoside analogs in thymidine kinase 2 deficient human fibroblasts.

Science.gov (United States)

Bjerke, Mia; Solaroli, Nicola; Lesko, Nicole; Balzarini, Jan; Johansson, Magnus; Karlsson, Anna

2010-01-01

Thymidine kinase 2 (TK2) is a mitochondrial deoxyribonucleoside kinase that phosphorylates several nucleoside analogs used in anti-viral and anti-cancer therapy. A fibroblast cell line with decreased TK2 activity was investigated in order to obtain insights in the effects of TK2 deficiency on nucleotide metabolism. The role of TK2 for the sensitivity against cytotoxic nucleoside analogs was also investigated. The TK2 deficient cells retained their sensitivity against all pyrimidine nucleoside analogs tested. This study suggests that nucleoside analog phosphorylation mediated by TK2 may be less important, compared to other deoxyribonucleoside kinases, for the cytotoxic effects of these compounds.

Three-Dimentional Structures of Autophosphorylation Complexes in Crystals of Protein Kinases

KAUST Repository

Dumbrack, Roland

2016-01-26

Protein kinase autophosphorylation is a common regulatory mechanism in cell signaling pathways. Several autophosphorylation complexes have been identified in crystals of protein kinases, with a known serine, threonine, or tyrosine autophosphorylation site of one kinase monomer sitting in the active site of another monomer of the same protein in the crystal. We utilized a structural bioinformatics method to identify all such autophosphorylation complexes in X-ray crystallographic structures in the Protein Data Bank (PDB) by generating all unique kinase/kinase interfaces within and between asymmetric units of each crystal and measuring the distance between the hydroxyl oxygen of potential autophosphorylation sites and the oxygen atoms of the active site aspartic acid residue side chain. We have identified 15 unique autophosphorylation complexes in the PDB, of which 5 complexes have not previously been described in the relevant publications on the crystal structures (N-terminal juxtamembrane regions of CSF1R and EPHA2, activation loop tyrosines of LCK and IGF1R, and a serine in a nuclear localization signal region of CLK2. Mutation of residues in the autophosphorylation complex interface of LCK either severely impaired autophosphorylation or increased it. Taking the autophosphorylation complexes as a whole and comparing them with peptide-substrate/kinase complexes, we observe a number of important features among them. The novel and previously observed autophosphorylation sites are conserved in many kinases, indicating that by homology we can extend the relevance of these complexes to many other clinically relevant drug targets.

A screen for kinase inhibitors identifies antimicrobial imidazopyridine aminofurazans as specific inhibitors of the Listeria monocytogenes PASTA kinase PrkA.

Science.gov (United States)

Schaenzer, Adam J; Wlodarchak, Nathan; Drewry, David H; Zuercher, William J; Rose, Warren E; Striker, Rob; Sauer, John-Demian

2017-10-13

Bacterial signaling systems such as protein kinases and quorum sensing have become increasingly attractive targets for the development of novel antimicrobial agents in a time of rising antibiotic resistance. The family of bacterial P enicillin-binding-protein A nd S erine/ T hreonine kinase- A ssociated (PASTA) kinases is of particular interest due to the role of these kinases in regulating resistance to β-lactam antibiotics. As such, small-molecule kinase inhibitors that target PASTA kinases may prove beneficial as treatments adjunctive to β-lactam therapy. Despite this interest, only limited progress has been made in identifying functional inhibitors of the PASTA kinases that have both activity against the intact microbe and high kinase specificity. Here, we report the results of a small-molecule screen that identified GSK690693, an imidazopyridine aminofurazan-type kinase inhibitor that increases the sensitivity of the intracellular pathogen Listeria monocytogenes to various β-lactams by inhibiting the PASTA kinase PrkA. GSK690693 potently inhibited PrkA kinase activity biochemically and exhibited significant selectivity for PrkA relative to the Staphylococcus aureus PASTA kinase Stk1. Furthermore, other imidazopyridine aminofurazans could effectively inhibit PrkA and potentiate β-lactam antibiotic activity to varying degrees. The presence of the 2-methyl-3-butyn-2-ol (alkynol) moiety was important for both biochemical and antimicrobial activity. Finally, mutagenesis studies demonstrated residues in the back pocket of the active site are important for GSK690693 selectivity. These data suggest that targeted screens can successfully identify PASTA kinase inhibitors with both biochemical and antimicrobial specificity. Moreover, the imidazopyridine aminofurazans represent a family of PASTA kinase inhibitors that have the potential to be optimized for selective PASTA kinase inhibition.

Coupled motions in the SH2 and kinase domains of Csk control Src phosphorylation.

Science.gov (United States)

Wong, Lilly; Lieser, Scot A; Miyashita, Osamu; Miller, Meghan; Tasken, Kjetil; Onuchic, Josè N; Adams, Joseph A; Woods, Virgil L; Jennings, Patricia A

2005-08-05

The C-terminal Src kinase (Csk) phosphorylates and down-regulates Src family tyrosine kinases. The Csk-binding protein (Cbp) localizes Csk close to its substrates at the plasma membrane, and increases the specific activity of the kinase. To investigate this long-range catalytic effect, the phosphorylation of Src and the conformation of Csk were investigated in the presence of a high-affinity phosphopeptide derived from Cbp. This peptide binds tightly to the SH2 domain and enhances Src recognition (lowers K(m)) by increasing the apparent phosphoryl transfer rate in the Csk active site, a phenomenon detected in rapid quench flow experiments. Previous studies demonstrated that the regulation of Csk activity is linked to conformational changes in the enzyme that can be probed with hydrogen-deuterium exchange methods. We show that the Cbp peptide impacts deuterium incorporation into its binding partner (the SH2 domain), and into the SH2-kinase linker and several sequences in the kinase domain, including the glycine-rich loop in the active site. These findings, along with computational data from normal mode analyses, suggest that the SH2 domain moves in a cantilever fashion with respect to the small lobe of the kinase domain, ordering the active site for catalysis. The binding of a small Cbp-derived peptide to the SH2 domain of Csk modifies these motions, enhancing Src recognition.

Small Molecule Tyrosine Kinase Inhibitors of ErbB2/HER2/Neu in the Treatment of Aggressive Breast Cancer

Directory of Open Access Journals (Sweden)

Richard L. Schroeder

2014-09-01

Full Text Available The human epidermal growth factor receptor 2 (HER2 is a member of the erbB class of tyrosine kinase receptors. These proteins are normally expressed at the surface of healthy cells and play critical roles in the signal transduction cascade in a myriad of biochemical pathways responsible for cell growth and differentiation. However, it is widely known that amplification and subsequent overexpression of the HER2 encoding oncogene results in unregulated cell proliferation in an aggressive form of breast cancer known as HER2-positive breast cancer. Existing therapies such as trastuzumab (Herceptin® and lapatinib (Tyverb/Tykerb®, a monoclonal antibody inhibitor and a dual EGFR/HER2 kinase inhibitor, respectively, are currently used in the treatment of HER2-positive cancers, although issues with high recurrence and acquired resistance still remain. Small molecule tyrosine kinase inhibitors provide attractive therapeutic targets, as they are able to block cell signaling associated with many of the proposed mechanisms for HER2 resistance. In this regard we aim to present a review on the available HER2 tyrosine kinase inhibitors, as well as those currently in development. The use of tyrosine kinase inhibitors as sequential or combinatorial therapeutic strategies with other HER family inhibitors is also discussed.

Characterization of breakpoint cluster region kinase and SH2-binding activities.

Science.gov (United States)

Afar, D E; Witte, O N

1995-01-01

BCR is an interesting signaling protein, whose cellular function is currently unknown. Its biochemical properties include serine kinase activity, SH2-binding activity, and a GTPase-activating activity. The SH2-binding activity is particularly interesting because it may link BCR to signaling pathways involving SH2-containing molecules. Since tyrosine phosphorylation of BCR has been detected in CML-derived cell lines and since tyrosine-phosphorylated BCR shows increased affinity toward certain SH2 domains, it seems particularly important to further characterize this activity. This chapter described a simple purification scheme for partial purification of BCR, which can be used to assess in vitro kinase and SH2-binding activities.

Loss of thymidine kinase 2 alters neuronal bioenergetics and leads to neurodegeneration.

Science.gov (United States)

Bartesaghi, Stefano; Betts-Henderson, Joanne; Cain, Kelvin; Dinsdale, David; Zhou, Xiaoshan; Karlsson, Anna; Salomoni, Paolo; Nicotera, Pierluigi

2010-05-01

Mutations of thymidine kinase 2 (TK2), an essential component of the mitochondrial nucleotide salvage pathway, can give rise to mitochondrial DNA (mtDNA) depletion syndromes (MDS). These clinically heterogeneous disorders are characterized by severe reduction in mtDNA copy number in affected tissues and are associated with progressive myopathy, hepatopathy and/or encephalopathy, depending in part on the underlying nuclear genetic defect. Mutations of TK2 have previously been associated with an isolated myopathic form of MDS (OMIM 609560). However, more recently, neurological phenotypes have been demonstrated in patients carrying TK2 mutations, thus suggesting that loss of TK2 results in neuronal dysfunction. Here, we directly address the role of TK2 in neuronal homeostasis using a knockout mouse model. We demonstrate that in vivo loss of TK2 activity leads to a severe ataxic phenotype, accompanied by reduced mtDNA copy number and decreased steady-state levels of electron transport chain proteins in the brain. In TK2-deficient cerebellar neurons, these abnormalities are associated with impaired mitochondrial bioenergetic function, aberrant mitochondrial ultrastructure and degeneration of selected neuronal types. Overall, our findings demonstrate that TK2 deficiency leads to neuronal dysfunction in vivo, and have important implications for understanding the mechanisms of neurological impairment in MDS.

Transcriptional Regulation of S Phase Kinase-associated Protein 2 by NR4A Orphan Nuclear Receptor NOR1 in Vascular Smooth Muscle Cells*

Science.gov (United States)

Gizard, Florence; Zhao, Yue; Findeisen, Hannes M.; Qing, Hua; Cohn, Dianne; Heywood, Elizabeth B.; Jones, Karrie L.; Nomiyama, Takashi; Bruemmer, Dennis

2011-01-01

Members of the NR4A subgroup of the nuclear hormone receptor superfamily have emerged as key transcriptional regulators of proliferation and inflammation. NOR1 constitutes a ligand-independent transcription factor of this subgroup and induces cell proliferation; however, the transcriptional mechanisms underlying this mitogenic role remain to be defined. Here, we demonstrate that the F-box protein SKP2 (S phase kinase-associated protein 2), the substrate-specific receptor of the ubiquitin ligase responsible for the degradation of p27KIP1 through the proteasome pathway, constitutes a direct transcriptional target for NOR1. Mitogen-induced Skp2 expression is silenced in vascular smooth muscle cells (VSMC) isolated from Nor1-deficient mice or transfected with Nor1 siRNA. Conversely, adenovirus-mediated overexpression of NOR1 induces Skp2 expression in VSMC and decreases protein abundance of its target p27. Transient transfection experiments establish that NOR1 transactivates the Skp2 promoter through a nerve growth factor-induced clone B response element (NBRE). Electrophoretic mobility shift and chromatin immunoprecipitation assays further revealed that NOR1 is recruited to this NBRE site in the Skp2 promoter in response to mitogenic stimulation. In vivo Skp2 expression is increased during the proliferative response underlying neointima formation, and this transcriptional induction depends on the expression of NOR1. Finally, we demonstrate that overexpression of Skp2 rescues the proliferative arrest of Nor1-deficient VSMC. Collectively, these results characterize Skp2 as a novel NOR1-regulated target gene and detail a previously unrecognized transcriptional cascade regulating mitogen-induced VSMC proliferation. PMID:21868379

Nuclear AMPK regulated CARM1 stabilization impacts autophagy in aged heart

International Nuclear Information System (INIS)

Li, Chen; Yu, Lu; Xue, Han; Yang, Zheng; Yin, Yue; Zhang, Bo; Chen, Mai; Ma, Heng

2017-01-01

Senescence-associated autophagy downregulation leads to cardiomyocyte dysfunction. Coactivator-associated arginine methyltransferase 1 (CARM1) participates in many cellular processes, including autophagy in mammals. However, the effect of CARM1 in aging-related cardiac autophagy decline remains undefined. Moreover, AMP-activated protein kinase (AMPK) is a key regulator in metabolism and autophagy, however, the role of nuclear AMPK in autophagy outcome in aged hearts still unclear. Hers we identify the correlation between nuclear AMPK and CARM1 in aging heart. We found that fasting could promote autophagy in young hearts but not in aged hearts. The CARM1 stabilization is markedly decrease in aged hearts, which impaired nucleus TFEB-CARM1 complex and autophagy flux. Further, S-phase kinase-associated protein 2(SKP2), responsible for CARM1 degradation, was increased in aged hearts. We further validated that AMPK dependent FoxO3 phosphorylation was markedly reduced in nucleus, the decreased nuclear AMPK-FoxO3 activity fails to suppress SKP2-E3 ubiquitin ligase. This loss of repression leads to The CARM1 level and autophagy in aged hearts could be restored through AMPK activation. Taken together, AMPK deficiency results in nuclear CARM1 decrease mediated in part by SKP2, contributing to autophagy dysfunction in aged hearts. Our results identified nuclear AMPK controlled CARM1 stabilization as a new actor that regulates cardiac autophagy. - Highlights: • AMPK-dependent CARM1 stabilization is an important nuclear mechanism in cardiac autophagy. • AMPK deficiency lead to SKP2-mediated decrease in CARM1. • AMPK–SKP2–CARM1 in the regulation of autophagy dysfunction in aged heart.

Crystal structure of the catalytic subunit of protein kinase CK2 from Zea mays at 2.1 A resolution

DEFF Research Database (Denmark)

Niefind, K; Guerra, B; Pinna, L A

1998-01-01

CK2alpha is the catalytic subunit of protein kinase CK2, an acidophilic and constitutively active eukaryotic Ser/Thr kinase involved in cell proliferation. A crystal structure, at 2.1 A resolution, of recombinant maize CK2alpha (rmCK2alpha) in the presence of ATP and Mg2+, shows the enzyme in an ...

The carboxy terminus of p53 mimics the polylysine effect of protein kinase CK2-catalyzed MDM2 phosphorylation

DEFF Research Database (Denmark)

Guerra, B; Götz, C; Wagner, P

1997-01-01

The oncogene product MDM2 can be phosphorylated by protein kinase CK2 in vitro 0.5-1 mol of phosphate were incorporated per mol MDM2 protein. The catalytic subunit of protein kinase CK2 (alpha-subunit) catalyzed the incorporation of twice as much phosphate into the MDM2 protein as it was obtained...

Eukaryotic elongation factor 2 is a prognostic marker and its kinase a potential therapeutic target in HCC.

Science.gov (United States)

Pott, Leona L; Hagemann, Sascha; Reis, Henning; Lorenz, Kristina; Bracht, Thilo; Herold, Thomas; Skryabin, Boris V; Megger, Dominik A; Kälsch, Julia; Weber, Frank; Sitek, Barbara; Baba, Hideo A

2017-02-14

Hepatocellular carcinoma is a cancer with increasing incidence and largely refractory to current anticancer drugs. Since Sorafenib, a multikinase inhibitor has shown modest efficacy in advanced hepatocellular carcinoma additional treatments are highly needed. Protein phosphorylation via kinases is an important post-translational modification to regulate cell homeostasis including proliferation and apoptosis. Therefore kinases are valuable targets in cancer therapy. To this end we performed 2D differential gel electrophoresis and mass spectrometry analysis of phosphoprotein-enriched lysates of tumor and corresponding non-tumorous liver samples to detect differentially abundant phosphoproteins to screen for novel kinases as potential drug targets. We identified 34 differentially abundant proteins in phosphoprotein enriched lysates. Expression and distribution of the candidate protein eEF2 and its phosphorylated isoform was validated immunohistochemically on 78 hepatocellular carcinoma and non-tumorous tissue samples. Validation showed that total eEF2 and phosphorylated eEF2 at threonine 56 are prognostic markers for overall survival of HCC-patients. The activity of the regulating eEF2 kinase, compared between tumor and non-tumorous tissue lysates by in vitro kinase assays, is more than four times higher in tumor tissues. Functional analyzes regarding eEF2 kinase were performed in JHH5 cells with CRISPR/Cas9 mediated eEF2 kinase knock out. Proliferation and growth is decreased in eEF2 kinase knock out cells. eEF2 and phosphorylated eEF2 are prognostic markers for survival of hepatocellular carcinoma patients and the regulating eEF2 kinase is a potential drug target for tumor therapy.

Nuclear energy: strategy of public relations

Energy Technology Data Exchange (ETDEWEB)

Timell, S [Swedish Power Association, Stockholm, Sweden

1981-02-21

A referendum was held in Sweden on 23rd March 1980, stimulated by the Three Mile Island accident in USA, to determine the future nuclear power development policy. The electricity supply background is that in 1980, 65% of power was hydro, 25% nuclear and 10% coal and oil. In terms of total power consumption, the country is heavily dependent on oil, which represents about 75%. The intensive public relations activity previous to the referendum is described, and this involved fact accumulation and assimilation, dissemination through various media, including brochures, displays, films and leaflets. In the political arena three lines developed: (1) (Conservatives); continue nuclear power, building at least 12 reactors, (2) (Social democrats and liberals); similar to (1), but more cautious, with emphasis on energy conservation, (3) (Centre parties and communists); no more nuclear power, and prevention of uranium extraction in Sweden. The voting was (1) 18.9%, (2) 39.1%, (3) 38.7%, (No dec of the most topical is concerned with the inventory of risks due to each industrial energy sector. This session was in two parts, the first devoted to problems specific to each source of energy including nuclear, the second to commo The extension to longer distances may be made with caution and to the satisfaction of the regulatory authority.

Protein kinase CK2 structure-function relationship

DEFF Research Database (Denmark)

Boldyreff, B; Meggio, F; Pinna, L A

1994-01-01

Protein kinase CK2 subunits alpha and beta were expressed either separately or together in a bacterial expression system (pT7-7/BL21(DE3)) and purified to homogeneity. After mixing the subunits, a CK2 holoenzyme (alpha 2 beta 2) was spontaneously reconstituted, which displays identical features...... subunit have been prepared and assayed for their ability to assemble with the catalytic alpha subunit to give a fully competent CK2 holoenzyme. The beta subunit contains an acidic stretch (amino acid 55-64), which is obviously responsible for a negative control of enzyme activity since mutations...

The Abl SH2-kinase linker naturally adopts a conformation competent for SH3 domain binding.

Science.gov (United States)

Chen, Shugui; Brier, Sébastien; Smithgall, Thomas E; Engen, John R

2007-04-01

The core of the Abelson tyrosine kinase (c-Abl) is structurally similar to Src-family kinases where SH3 and SH2 domains pack against the backside of the kinase domain in the down-regulated conformation. Both kinase families depend upon intramolecular association of SH3 with the linker joining the SH2 and kinase domains for suppression of kinase activity. Hydrogen deuterium exchange (HX) and mass spectrometry (MS) were used to probe intramolecular interaction of the c-Abl SH3 domain with the linker in recombinant constructs lacking the kinase domain. Under physiological conditions, the c-Abl SH3 domain undergoes partial unfolding, which is stabilized by ligand binding, providing a unique assay for SH3:linker interaction in solution. Using this approach, we observed dynamic association of the SH3 domain with the linker in the absence of the kinase domain. Truncation of the linker before W254 completely prevented cis-interaction with SH3, while constructs containing amino acids past this point showed SH3:linker interactions. The observation that the Abl linker sequence exhibits SH3-binding activity in the absence of the kinase domain is unique to Abl and was not observed with Src-family kinases. These results suggest that SH3:linker interactions may have a more prominent role in Abl regulation than in Src kinases, where the down-regulated conformation is further stabilized by a second intramolecular interaction between the C-terminal tail and the SH2 domain.

A mathematical model of human thymidine kinase 2 activity

DEFF Research Database (Denmark)

Radivoyevitch, Tom; Munch-Petersen, Birgitte; Wang, Liya

2011-01-01

_ The mitochondrial enzyme thymidine kinase 2 (TK2) phosphorylates deoxythymidine (dT) and deoxycytidine (dC) to form dTMP and dCMP, which in cells rapidly become the negative-feedback end-products dTTP and dCTP. TK2 kinetic activity exhibits Hill coefficients of ∼0.5 (apparent negative cooperati...

Lipid Signaling via Pkh1/2 Regulates Fungal CO2 Sensing through the Kinase Sch9.

Science.gov (United States)

Pohlers, Susann; Martin, Ronny; Krüger, Thomas; Hellwig, Daniela; Hänel, Frank; Kniemeyer, Olaf; Saluz, Hans Peter; Van Dijck, Patrick; Ernst, Joachim F; Brakhage, Axel; Mühlschlegel, Fritz A; Kurzai, Oliver

2017-01-31

Adaptation to alternating CO 2 concentrations is crucial for all organisms. Carbonic anhydrases-metalloenzymes that have been found in all domains of life-enable fixation of scarce CO 2 by accelerating its conversion to bicarbonate and ensure maintenance of cellular metabolism. In fungi and other eukaryotes, the carbonic anhydrase Nce103 has been shown to be essential for growth in air (~0.04% CO 2 ). Expression of NCE103 is regulated in response to CO 2 availability. In Saccharomyces cerevisiae, NCE103 is activated by the transcription factor ScCst6, and in Candida albicans and Candida glabrata, it is activated by its homologues CaRca1 and CgRca1, respectively. To identify the kinase controlling Cst6/Rca1, we screened an S. cerevisiae kinase/phosphatase mutant library for the ability to regulate NCE103 in a CO 2 -dependent manner. We identified ScSch9 as a potential ScCst6-specific kinase, as the sch9Δ mutant strain showed deregulated NCE103 expression on the RNA and protein levels. Immunoprecipitation revealed the binding capabilities of both proteins, and detection of ScCst6 phosphorylation by ScSch9 in vitro confirmed Sch9 as the Cst6 kinase. We could show that CO 2 -dependent activation of Sch9, which is part of a kinase cascade, is mediated by lipid/Pkh1/2 signaling but not TORC1. Finally, we tested conservation of the identified regulatory cascade in the pathogenic yeast species C. albicans and C. glabrata Deletion of SCH9 homologues of both species impaired CO 2 -dependent regulation of NCE103 expression, which indicates a conservation of the CO 2 adaptation mechanism among yeasts. Thus, Sch9 is a Cst6/Rca1 kinase that links CO 2 adaptation to lipid signaling via Pkh1/2 in fungi. All living organisms have to cope with alternating CO 2 concentrations as CO 2 levels range from very low in the atmosphere (0.04%) to high (5% and more) in other niches, including the human body. In fungi, CO 2 is sensed via two pathways. The first regulates virulence in

R2 Metropolitan Division, 2013; TIGER/Line Shapefile

Data.gov (United States)

U.S. Environmental Protection Agency — The TIGER/Line shapefiles and related database files (.dbf) are an extract of selected geographic and cartographic information from the U.S. Census Bureau's Master...

Casein Kinase 2 Reverses Tail-Independent Inactivation of Kinesin-1

Science.gov (United States)

Xu, Jing

2013-03-01

Kinesin-1 is a plus-end microtubule-based motor, and defects in kinesin-based transport are linked to diseases including neurodegeneration. Kinesin can auto-inhibit via a head-tail interaction, but is believed to be active otherwise. Here we report a tail-independent inactivation of kinesin, reversible by the disease-relevant signalling protein, casein kinase 2 (CK2). The majority of initially active kinesin (native or tail-less) loses its ability to interact with microtubules in vitro, and CK2 reverses this inactivation (approximately fourfold) without altering kinesin's single motor properties. This activation pathway does not require motor phosphorylation, and is independent of head-tail auto-inhibition. In cultured mammalian cells, reducing CK2 expression, but not its kinase activity, decreases the force required to stall lipid droplet transport, consistent with a decreased number of active kinesin motors. Our results (Nat. Commun., 3:754, 2012) provide the first direct evidence of a protein kinase upregulating kinesin-based transport, and suggest a novel pathway for regulating the activity of cargo-bound kinesin. Work supported by NIGMS grants GM64624 to SPG, GM74830-06A1 to LH, GM76516 to LB, NS048501 to SJK, and AHA grant 825278F to JX.

Cancer metabolism meets systems biology: Pyruvate kinase isoform PKM2 is a metabolic master regulator

OpenAIRE

Fabian V Filipp

2013-01-01

Pyruvate kinase activity is controlled by a tightly woven regulatory network. The oncofetal isoform of pyruvate kinase (PKM2) is a master regulator of cancer metabolism. PKM2 engages in parallel, feed-forward, positive and negative feedback control contributing to cancer progression. Besides its metabolic role, non-metabolic functions of PKM2 as protein kinase and transcriptional coactivator for c-MYC and hypoxia-inducible factor 1-alpha are essential for epidermal growth factor receptor acti...

Protein kinase CK2 phosphorylates the Fas-associated factor FAF1 in vivo and influences its transport into the nucleus

DEFF Research Database (Denmark)

Olsen, Birgitte B; Jessen, Vibeke; Højrup, Peter

2003-01-01

We previously identified the Fas-associated factor FAF1 as an in vitro substrate of protein kinase CK2 and determined Ser289 and Ser291 as phosphorylation sites. Here we demonstrate that these two serine residues are the only sites phosphorylated by CK2 in vitro, and that at least one site...... is phosphorylated in vivo. Furthermore, we analyzed putative physiological functions of FAF1 phosphorylation. The ability of FAF1 to potentiate Fas-induced apoptosis is not influenced by the FAF1 phosphorylation status; however, the nuclear import of a phosphorylation-deficient FAF1 mutant was delayed in comparison...

Survey of tyrosine kinase signaling reveals ROS kinase fusions in human cholangiocarcinoma.

Directory of Open Access Journals (Sweden)

Ting-Lei Gu

Full Text Available Cholangiocarcinoma, also known as bile duct cancer, is the second most common primary hepatic carcinoma with a median survival of less than 2 years. The molecular mechanisms underlying the development of this disease are not clear. To survey activated tyrosine kinases signaling in cholangiocarcinoma, we employed immunoaffinity profiling coupled to mass spectrometry and identified DDR1, EPHA2, EGFR, and ROS tyrosine kinases, along with over 1,000 tyrosine phosphorylation sites from about 750 different proteins in primary cholangiocarcinoma patients. Furthermore, we confirmed the presence of ROS kinase fusions in 8.7% (2 out of 23 of cholangiocarcinoma patients. Expression of the ROS fusions in 3T3 cells confers transforming ability both in vitro and in vivo, and is responsive to its kinase inhibitor. Our data demonstrate that ROS kinase is a promising candidate for a therapeutic target and for a diagnostic molecular marker in cholangiocarcinoma. The identification of ROS tyrosine kinase fusions in cholangiocarcinoma, along with the presence of other ROS kinase fusions in lung cancer and glioblastoma, suggests that a more broadly based screen for activated ROS kinase in cancer is warranted.

Subcellular distribution of cyclin-dependent kinase-like 5 (CDKL5) is regulated through phosphorylation by dual specificity tyrosine-phosphorylation-regulated kinase 1A (DYRK1A)

International Nuclear Information System (INIS)

Oi, Ami; Katayama, Syouichi; Hatano, Naoya; Sugiyama, Yasunori; Kameshita, Isamu; Sueyoshi, Noriyuki

2017-01-01

Cyclin-dependent kinase-like 5 (CDKL5) is a Ser/Thr protein kinase primarily expressed in the central nervous system and is known to cause X-linked neurodevelopmental disorders such as Rett syndrome. However, the mechanisms regulating CDKL5 have not yet been fully clarified. Therefore, in this study, we investigated the protein kinase that directly phosphorylates CDKL5, identifying it as dual specificity tyrosine-phosphorylation-regulated kinase 1A (DYRK1A), an enzyme binding to and phosphorylating CDKL5. We showed that subcellular distribution of CDKL5 was regulated by its phosphorylation by DYRK1A. In mouse neuroblastoma Neuro2a cells, CDKL5 was localized in both the cytosol and nucleus, whereas DYRK1A showed a typical nuclear localization. When CDKL5 and DYRK1A were co-expressed, the cytosolic localization of CDKL5 was significantly increased. Results of site-directed mutagenesis revealed that the phosphorylation site was Ser-308, in the vicinity of the nuclear localization signal. A mutation mimicking the phosphorylated serine residue by aspartate substitution (S308D) changed CDKL5 localization to the cytosol, whereas the corresponding alanine-substituted analog, CDKL5(S308A), was primarily localized to the nucleus. Taken together, these results strongly suggested that DYRK1A bound to CDKL5 and phosphorylated it on Ser-308, thus interfering with its nuclear localization. - Highlights: • We investigated the mechanism regulating subcellular localization of CDKL5. • DYRK1A was identified as an enzyme that bound to and phosphorylated CDKL5. • The phosphorylation site of CDKL5 was Ser-308, in the vicinity of the NLS. • When DYRK1A was co-expressed, the cytosolic CDKL5 was significantly increased. • In conclusion, DYRK1A regulates CDKL5 localization via phosphorylation on Ser-308.

Deoxyribonucleoside kinases in mitochondrial DNA depletion.

Science.gov (United States)

Saada-Reisch, Ann

2004-10-01

Mitochondrial DNA (mtDNA) depletion syndromes (MDS) are a heterogeneous group of mitochondrial disorders, manifested by a decreased mtDNA copy number and respiratory chain dysfunction. Primary MDS are inherited autosomally and may affect a single organ or multiple tissues. Mutated mitochondrial deoxyribonucleoside kinases; deoxyguanosine kinase (dGK) and thymidine kinase 2 (TK2), were associated with the hepatocerebral and myopathic forms of MDS respectively. dGK and TK2 are key enzymes in the mitochondrial nucleotide salvage pathway, providing the mitochondria with deoxyribonucleotides (dNP) essential for mtDNA synthesis. Although the mitochondrial dNP pool is physically separated from the cytosolic one, dNP's may still be imported through specific transport. Non-replicating tissues, where cytosolic dNP supply is down regulated, are thus particularly vulnerable to dGK and TK2 deficiency. The overlapping substrate specificity of deoxycytidine kinase (dCK) may explain the relative sparing of muscle in dGK deficiency, while low basal TK2 activity render this tissue susceptible to TK2 deficiency. The precise pathophysiological mechanisms of mtDNA depletion due to dGK and TK2 deficiencies remain to be determined, though recent findings confirm that it is attributed to imbalanced dNTP pools.

Visual Snapshots of Intracellular Kinase Activity At The Onset of Mitosis

Science.gov (United States)

Dai, Zhaohua; Dulyaninova, Natalya G.; Kumar, Sanjai; Bresnick, Anne R.; Lawrence, David S.

2007-01-01

Summary Visual snapshots of intracellular kinase activity can be acquired with exquisite temporal control using a light-activatable (caged) sensor, thereby providing a means to interrogate enzymatic activity at any point during the cell division cycle. Robust protein kinase activity transpires just prior to, but not immediately following, nuclear envelope breakdown (NEB). Furthermore, kinase activity is required for progression from prophase into metaphase. Finally, the application of selective protein kinase C (PKC) inhibitors, in combination with the caged sensor, correlates the action of the PKC β isoform with subsequent NEB. PMID:18022564

Phosphorylation of the Grb2- and phosphatidylinositol 3-kinase p85-binding p36/38 by Syk in Lck-negative T cells.

Science.gov (United States)

von Willebrand, M; Williams, S; Tailor, P; Mustelin, T

1998-06-01

Activation of the mitogen-activated protein kinase (MAPK) pathway by the T-cell antigen receptor (TCR) in T cells involves a positive role for phosphatidylinositol 3-kinase (PI3K) activity. We recently reported that over-expression of the Syk protein tyrosine kinase in the Lck-negative JCaM1 cells enabled the TCR to induce a normal activation of the Erk2 MAPK and enhanced transcription of a reporter gene driven by the nuclear factor of activated T cells and AP-1. Because this system allows us to analyse the targets for Syk in receptor-mediated signalling, we examined the role of PI3K in signalling events between the TCR-regulated Syk and the downstream activation of Erk2. We report that inhibition of PI3K by wortmannin or an inhibitory p85 construct, p85deltaiSH2, reduced the TCR-induced Syk-dependent activation of Erk2, as well as the appearance of phospho-Erk and phospho-Mek. At the same time, expression of Syk resulted in the activation-dependent phosphorylation of three proteins that bound to the src homology 2 (SH2) domains of PI3K p85. The strongest of these bands had an apparent molecular mass of 36-38 kDa on SDS gels, and it was quantitatively removed from the lysates by adsorption to a fusion protein containing the SH2 domain of Grb2. The appearance of this band was Syk dependent, and it was seen only upon triggering of the TCR complex. Thus, p36/38 was phosphorylated by Syk or a Syk-regulated kinase, and this protein may provide a link to the recruitment and activation of PI3K, as well as to the Ras-MAPK pathway, in TCR-triggered T cells.

Expression and purification of functional JNK2beta2: perspectives on high-level production of recombinant MAP kinases.

Science.gov (United States)

Savopoulos, John W; Dowd, Stephen; Armour, Carolyn; Carter, Paul S; Greenwood, Catherine J; Mills, David; Powell, David; Pettman, Gary R; Jenkins, Owen; Walsh, Frank S; Philpott, Karen L

2002-02-01

The mitogen-activated protein (MAP) kinases are a group of serine/threonine kinases that mediate intracellular signal transduction in response to environmental stimuli including stress, growth factors, and various cytokines. Of this family, the c-Jun N-terminal kinases (JNKs) are members which, depending on cell type, have been shown to activate the transcription of genes involved in the inflammatory response, apoptosis, and hypertrophy. Here we report the use Baculovirus/Sf9 cells to produce milligram quantities of recombinant JNK2beta2 substrate which could be purified to >90% as judged by SDS-PAGE. In addition, we report a novel method for the site-specific biotinylation for this enzyme and demonstrate that the biotinylated product is an authentic substrate of the upstream kinases MKK4 and 7 and can phosphorylate a downstream target, ATF-2. We also show that the phosphorylated product can be captured efficiently on streptavidin-coated beads for use in scintillation proximity assays. Copyright 2002 Elsevier Science (USA).

Nitrosative/oxidative stress conditions regulate thioredoxin-interacting protein (TXNIP) expression and thioredoxin-1 (TRX-1) nuclear localization.

Science.gov (United States)

Ogata, Fernando Toshio; Batista, Wagner Luiz; Sartori, Adriano; Gesteira, Tarsis Ferreira; Masutani, Hiroshi; Arai, Roberto Jun; Yodoi, Junji; Stern, Arnold; Monteiro, Hugo Pequeno

2013-01-01

Thioredoxin (TRX-1) is a multifunctional protein that controls the redox status of other proteins. TRX-1 can be found in the extracellular milieu, cytoplasm and nucleus, and it has distinct functions in each environment. Previously, we studied the intracellular localization of TRX-1 and its relationship with the activation of the p21Ras-ERK1/2 MAP Kinases signaling pathway. In situations where this pathway was activated by stress conditions evoked by a nitrosothiol, S-nitroso-N-acetylpenicillamine (SNAP), TRX-1 accumulated in the nuclear compartment due to nitrosylation of p21Ras and activation of downstream ERK1/2 MAP kinases. Presently, we demonstrate that ERK1/2 MAP Kinases activation and spatial distribution within cells trigger TRX-1 nuclear translocation through down-regulation of the physiological inhibitor of TRX-1, Thioredoxin Interacting Protein (TXNIP). Once activated by the oxidants, SNAP and H₂O₂, the ERK1/2 MAP kinases migrate to the nucleus. This is correlated with down-regulation of TXNIP. In the presence of the MEK inhibitors (PD98059 or UO126), or in cells transfected with the Protein Enriched in Astrocytes (PEA-15), a cytoplasmic anchor of ERK1/2 MAP kinases, TRX-1 nuclear migration and TXNIP down-regulation are no longer observed in cells exposed to oxidants. On the other hand, over-expression of TXNIP abolishes nuclear migration of TRX-1 under nitrosative/oxidative stress conditions, whereas gene silencing of TXNIP facilitates nuclear migration even in the absence of stress conditions. Studies based on the TXNIP promoter support this regulation. In conclusion, changes in TRX-1 compartmentalization under nitrosative/oxidative stress conditions are dependent on the expression levels of TXNIP, which are regulated by cellular compartmentalization and activation of the ERK1/2 MAP kinases.

Nitrosative/oxidative stress conditions regulate thioredoxin-interacting protein (TXNIP expression and thioredoxin-1 (TRX-1 nuclear localization.

Directory of Open Access Journals (Sweden)

Fernando Toshio Ogata

Full Text Available Thioredoxin (TRX-1 is a multifunctional protein that controls the redox status of other proteins. TRX-1 can be found in the extracellular milieu, cytoplasm and nucleus, and it has distinct functions in each environment. Previously, we studied the intracellular localization of TRX-1 and its relationship with the activation of the p21Ras-ERK1/2 MAP Kinases signaling pathway. In situations where this pathway was activated by stress conditions evoked by a nitrosothiol, S-nitroso-N-acetylpenicillamine (SNAP, TRX-1 accumulated in the nuclear compartment due to nitrosylation of p21Ras and activation of downstream ERK1/2 MAP kinases. Presently, we demonstrate that ERK1/2 MAP Kinases activation and spatial distribution within cells trigger TRX-1 nuclear translocation through down-regulation of the physiological inhibitor of TRX-1, Thioredoxin Interacting Protein (TXNIP. Once activated by the oxidants, SNAP and H₂O₂, the ERK1/2 MAP kinases migrate to the nucleus. This is correlated with down-regulation of TXNIP. In the presence of the MEK inhibitors (PD98059 or UO126, or in cells transfected with the Protein Enriched in Astrocytes (PEA-15, a cytoplasmic anchor of ERK1/2 MAP kinases, TRX-1 nuclear migration and TXNIP down-regulation are no longer observed in cells exposed to oxidants. On the other hand, over-expression of TXNIP abolishes nuclear migration of TRX-1 under nitrosative/oxidative stress conditions, whereas gene silencing of TXNIP facilitates nuclear migration even in the absence of stress conditions. Studies based on the TXNIP promoter support this regulation. In conclusion, changes in TRX-1 compartmentalization under nitrosative/oxidative stress conditions are dependent on the expression levels of TXNIP, which are regulated by cellular compartmentalization and activation of the ERK1/2 MAP kinases.

Drosophila Protein Kinase CK2: Genetics, Regulatory Complexity and Emerging Roles during Development

Directory of Open Access Journals (Sweden)

Mohna Bandyopadhyay

2016-12-01

Full Text Available CK2 is a Ser/Thr protein kinase that is highly conserved amongst all eukaryotes. It is a well-known oncogenic kinase that regulates vital cell autonomous functions and animal development. Genetic studies in the fruit fly Drosophila are providing unique insights into the roles of CK2 in cell signaling, embryogenesis, organogenesis, neurogenesis, and the circadian clock, and are revealing hitherto unknown complexities in CK2 functions and regulation. Here, we review Drosophila CK2 with respect to its structure, subunit diversity, potential mechanisms of regulation, developmental abnormalities linked to mutations in the gene encoding CK2 subunits, and emerging roles in multiple aspects of eye development. We examine the Drosophila CK2 “interaction map” and the eye-specific “transcriptome” databases, which raise the prospect that this protein kinase has many additional targets in the developing eye. We discuss the possibility that CK2 functions during early retinal neurogenesis in Drosophila and mammals bear greater similarity than has been recognized, and that this conservation may extend to other developmental programs. Together, these studies underscore the immense power of the Drosophila model organism to provide new insights and avenues to further investigate developmentally relevant targets of this protein kinase.

Nuclear energy related research

International Nuclear Information System (INIS)

Salminen, Pertti

1989-03-01

This annual Research Programme Plan covers the publicly funded nuclear energy related research planned to be carried out at the Technical Research Centre of Finland (VTT) in 1989. The research will be financed by the Ministry of Trade and Industry, the Finnish Centre for Radiation and Nuclear Safety, the Nordic Council of Ministers and VTT itself

Nuclear energy related research

International Nuclear Information System (INIS)

Salminen, P.

1988-02-01

This annual Research Programme Plan covers the publicly funded nuclear energy related research planned to be carried out at the Technical Research Centre of Finland (VTT) in 1988. The research will be financed by the Ministry of Trade and Industry, the Finnish Centre for Radiation and Nuclear Safety, the Nordic Council of Ministers and VTT itself

The Drosophila IKK-related kinase (Ik2 and Spindle-F proteins are part of a complex that regulates cytoskeleton organization during oogenesis

Directory of Open Access Journals (Sweden)

Shaanan Boaz

2008-09-01

Full Text Available Abstract Background IkappaB kinases (IKKs regulate the activity of Rel/NF-kappaB transcription factors by targeting their inhibitory partner proteins, IkappaBs, for degradation. The Drosophila genome encodes two members of the IKK family. Whereas the first is a kinase essential for activation of the NF-kappaB pathway, the latter does not act as IkappaB kinase. Instead, recent findings indicate that Ik2 regulates F-actin assembly by mediating the function of nonapoptotic caspases via degradation of DIAP1. Also, it has been suggested that ik2 regulates interactions between the minus ends of the microtubules and the actin-rich cortex in the oocyte. Since spn-F mutants display oocyte defects similar to those of ik2 mutant, we decided to investigate whether Spn-F could be a direct regulatory target of Ik2. Results We found that Ik2 binds physically to Spn-F, biomolecular interaction analysis of Spn-F and Ik2 demonstrating that both proteins bind directly and form a complex. We showed that Ik2 phosphorylates Spn-F and demonstrated that this phosphorylation does not lead to Spn-F degradation. Ik2 is localized to the anterior ring of the oocyte and to punctate structures in the nurse cells together with Spn-F protein, and both proteins are mutually required for their localization. Conclusion We conclude that Ik2 and Spn-F form a complex, which regulates cytoskeleton organization during Drosophila oogenesis and in which Spn-F is the direct regulatory target for Ik2. Interestingly, Ik2 in this complex does not function as a typical IKK in that it does not direct SpnF for degradation following phosphorylation.

Receptor-interacting protein (RIP) kinase family

OpenAIRE

Zhang, Duanwu; Lin, Juan; Han, Jiahuai

2010-01-01

Receptor-interacting protein (RIP) kinases are a group of threonine/serine protein kinases with a relatively conserved kinase domain but distinct non-kinase regions. A number of different domain structures, such as death and caspase activation and recruitment domain (CARD) domains, were found in different RIP family members, and these domains should be keys in determining the specific function of each RIP kinase. It is known that RIP kinases participate in different biological processes, incl...

Public relations strategy for the completion of Angra 2 nuclear power plant

International Nuclear Information System (INIS)

Kepinski, Alessandra

1998-01-01

In the 60's, the general public in Brazil knew little about nuclear energy. The country was under Military Rule since 1964 and, in the public's ind, the Nuclear Program was closely linked to nuclear weapons, being viewed with distrust and, even, fear. Governmental policies in this field were secret - when the decisions were made to built Angra 1 in 1968 and to sign the Nuclear Cooperation Agreement with Germany in 1975 - the public learned about them as a 'fait accompli'. In the late 70's, people started to hear about the delays in the commissioning of Angra 1 and the problems in the construction of the pile foundations of Angra 2. In 1980, following the TMI accident, the Federal Government issued a set of regulations dealing with emergency planning, the Federal and State Civil Defense being responsible for the preparation of the Off-Site Emergency Plan. FURNAS first public information campaign in 1982 dealt with emergency procedures and was directed to the Angra NPP employees and their families; local residents were visited by Civil Defense officials in 1983. At that time, the Brazilian Nuclear Program began to be criticized by concerned scientists and by the press, primarily due to its lack of transparency and its large scope. Safety issues arising from the TMI accident, lack of decision for the radioactive waste storage and problems with some equipment and components that delayed the commissioning of Angra 1, were pointed out as technical arguments against the construction of Angra 2 and 3. A new Constitution, 1988, required that a nuclear projects must be approved by the National Congress and put forward some new provisions for the environmental licensing of major industrial installations. The completion of Angra 2 was considered of the utmost importance by the Brazilian Nuclear Energy Association - ABEN, which is a technical-scientific body comprising employees from the various organizations that form the Brazilian Nuclear Sector. As an independent, non

Re-thinking china's densified biomass fuel policies: Large or small scale?

International Nuclear Information System (INIS)

Shan, Ming; Li, Dingkai; Jiang, Yi; Yang, Xudong

2016-01-01

Current policies and strategies related to the utilization of densified biomass fuel (DBF) in China are mainly focused on medium- or large-scale manufacturing modes, which cannot provide feasible solutions to solve the household energy problems in China's rural areas. To simplify commercial processes related to the collection of DBF feedstock and the production and utilization of fuel, a novel village-scale DBF approach is proposed. Pilot demonstration projects have shown the feasibility and flexibility of this new approach in realizing sustainable development in rural China. Effective utilization of DBF in rural China will lead to gains for global, regional, and local energy savings, environmental protection, sustainable development, and related social benefits. It could also benefit other developing countries for better utilization of biomass as a viable household energy source. This proposal therefore delivers the possibility of reciprocal gains, and as such deserves the attention of policy makers and various stakeholders. - Highlights: •A field survey of Chinese densified biomass fuel (DBF) development is conducted. •The current situation and problems related to China's DBF industry are analyzed. •A novel and viable village-scale DBF utilization mode is proposed. •Further actions are suggested to boost the utilization of DBF in rural China.

Skeletal muscle mitochondrial respiration in AMPKa2 kinase dead mice

DEFF Research Database (Denmark)

Larsen, Steen; Kristensen, Jonas Møller; Stride, Nis

2012-01-01

AIM: To study if the phenotypical characteristics (exercise intolerance; reduced spontaneous activity) of the AMPKa2 kinase-dead (KD) mice can be explained by a reduced mitochondrial respiratory flux rates (JO(2) ) in skeletal muscle. Secondly, the effect of the maturation process on JO(2...

High glucose induces inflammatory cytokine through protein kinase C-induced toll-like receptor 2 pathway in gingival fibroblasts

International Nuclear Information System (INIS)

Jiang, Shao-Yun; Wei, Cong-Cong; Shang, Ting-Ting; Lian, Qi; Wu, Chen-Xuan; Deng, Jia-Yin

2012-01-01

Highlights: ► High glucose significantly induced TLR2 expression in gingival fibroblasts. ► High glucose increased NF-κB p65 nuclear activity, IL-1β and TNF-α levels. ► PKC-α/δ-TLR2 pathway is involved in periodontal inflammation under high glucose. -- Abstract: Toll-like receptors (TLRs) play a key role in innate immune response and inflammation, especially in periodontitis. Meanwhile, hyperglycemia can induce inflammation in diabetes complications. However, the activity of TLRs in periodontitis complicated with hyperglycemia is still unclear. In the present study, high glucose (25 mmol/l) significantly induced TLR2 expression in gingival fibroblasts (p < 0.05). Also, high glucose increased nuclear factor kappa B (NF-κB) p65 nuclear activity, tumor necrosis factor-α (TNF-α) and interleukin-lβ (IL-1β) levels. Protein kinase C (PKC)-α and δ knockdown with siRNA significantly decreased TLR2 and NF-κB p65 expression (p < 0.05), whereas inhibition of PKC-β had no effect on TLR2 and NF-κB p65 under high glucose (p < 0.05). Additional studies revealed that TLR2 knockdown significantly abrogated high-glucose-induced NF-κB expression and inflammatory cytokine secretion. Collectively, these data suggest that high glucose stimulates TNF-α and IL-1β secretion via inducing TLR2 through PKC-α and PKC-δ in human gingival fibroblasts.

High glucose induces inflammatory cytokine through protein kinase C-induced toll-like receptor 2 pathway in gingival fibroblasts

Energy Technology Data Exchange (ETDEWEB)

Jiang, Shao-Yun, E-mail: jiangshaoyun@yahoo.com [School of Dentistry, Tianjin Medical University, 12 Qi Xiang Tai Street, Heping District, Tianjin 300070 (China); Wei, Cong-Cong; Shang, Ting-Ting; Lian, Qi; Wu, Chen-Xuan [School of Dentistry, Tianjin Medical University, 12 Qi Xiang Tai Street, Heping District, Tianjin 300070 (China); Deng, Jia-Yin, E-mail: yazhou2991@126.com [School of Dentistry, Tianjin Medical University, 12 Qi Xiang Tai Street, Heping District, Tianjin 300070 (China)

2012-10-26

Highlights: Black-Right-Pointing-Pointer High glucose significantly induced TLR2 expression in gingival fibroblasts. Black-Right-Pointing-Pointer High glucose increased NF-{kappa}B p65 nuclear activity, IL-1{beta} and TNF-{alpha} levels. Black-Right-Pointing-Pointer PKC-{alpha}/{delta}-TLR2 pathway is involved in periodontal inflammation under high glucose. -- Abstract: Toll-like receptors (TLRs) play a key role in innate immune response and inflammation, especially in periodontitis. Meanwhile, hyperglycemia can induce inflammation in diabetes complications. However, the activity of TLRs in periodontitis complicated with hyperglycemia is still unclear. In the present study, high glucose (25 mmol/l) significantly induced TLR2 expression in gingival fibroblasts (p < 0.05). Also, high glucose increased nuclear factor kappa B (NF-{kappa}B) p65 nuclear activity, tumor necrosis factor-{alpha} (TNF-{alpha}) and interleukin-l{beta} (IL-1{beta}) levels. Protein kinase C (PKC)-{alpha} and {delta} knockdown with siRNA significantly decreased TLR2 and NF-{kappa}B p65 expression (p < 0.05), whereas inhibition of PKC-{beta} had no effect on TLR2 and NF-{kappa}B p65 under high glucose (p < 0.05). Additional studies revealed that TLR2 knockdown significantly abrogated high-glucose-induced NF-{kappa}B expression and inflammatory cytokine secretion. Collectively, these data suggest that high glucose stimulates TNF-{alpha} and IL-1{beta} secretion via inducing TLR2 through PKC-{alpha} and PKC-{delta} in human gingival fibroblasts.

2,5-hexanedione (HD) treatment alters calmodulin, Ca2+/calmodulin-dependent protein kinase II, and protein kinase C in rats' nerve tissues

International Nuclear Information System (INIS)

Wang Qingshan; Hou Liyan; Zhang Cuili; Zhao Xiulan; Yu Sufang; Xie, Ke-Qin

2008-01-01

Calcium-dependent mechanisms, particularly those mediated by Ca 2+ /calmodulin (CaM)-dependent protein kinase II (CaMKII), have been implicated in neurotoxicant-induced neuropathy. However, it is unknown whether similar mechanisms exist in 2,5-hexanedione (HD)-induced neuropathy. For that, we investigated the changes of CaM, CaMKII, protein kinase C (PKC) and polymerization ratios (PRs) of NF-L, NF-M and NF-H in cerebral cortex (CC, including total cortex and some gray), spinal cord (SC) and sciatic nerve (SN) of rats treated with HD at a dosage of 1.75 or 3.50 mmol/kg for 8 weeks (five times per week). The results showed that CaM contents in CC, SC and SN were significantly increased, which indicated elevation of Ca 2+ concentrations in nerve tissues. CaMKII contents and activities were also increased in CC and were positively correlated with gait abnormality, but it could not be found in SC and SN. The increases of PKC contents and activities were also observed in SN and were positively correlated with gait abnormality. Except for that of NF-M in CC, the PRs of NF-L, NF-M and NF-H were also elevated in nerve tissues, which was consistent with the activation of protein kinases. The results suggested that CaMKII might be partly (in CC but not in SC and SN) involved in HD-induced neuropathy. CaMKII and PKC might mediate the HD neurotoxicity by altering the NF phosphorylation status and PRs

Arabidopsis decuple mutant reveals the importance of SnRK2 kinases in osmotic stress responses in vivo

KAUST Repository

Fujii, Hiroaki

2011-01-10

Osmotic stress associated with drought or salinity is a major factor that limits plant productivity. Protein kinases in the SNF1-related protein kinase 2 (SnRK2) family are activated by osmotic stress, suggesting that the kinases are involved in osmotic stress signaling. However, due to functional redundancy, their contribution to osmotic stress responses remained unclear. In this report, we constructed an Arabidopsis line carrying mutations in all 10 members of the SnRK2 family. The decuple mutant snrk2.1/2/3/4/5/6/7/8/9/10 grew poorly under hyperosmotic stress conditions but was similar to the wild type in culture media in the absence of osmotic stress. The mutant was also defective in gene regulation and the accumulation of abscisic acid (ABA), proline, and inositol 1,4,5-trisphosphate under osmotic stress. In addition, analysis of mutants defective in the ABA-activated SnRK2s (snrk2.2/3/6) and mutants defective in the rest of the SnRK2s (snrk2.1/4/5/7/8/9/10) revealed that SnRK2s are a merging point of ABA-dependent and -independent pathways for osmotic stress responses. These results demonstrate critical functions of the SnRK2s in mediating osmotic stress signaling and tolerance.

Protein kinase D stabilizes aldosterone-induced ERK1/2 MAP kinase activation in M1 renal cortical collecting duct cells to promote cell proliferation.

LENUS (Irish Health Repository)

McEneaney, Victoria

2010-01-01

Aldosterone elicits transcriptional responses in target tissues and also rapidly stimulates the activation of protein kinase signalling cascades independently of de novo protein synthesis. Here we investigated aldosterone-induced cell proliferation and extra-cellular regulated kinase 1 and 2 (ERK1\\/2) mitogen activated protein (MAP) kinase signalling in the M1 cortical collecting duct cell line (M1-CCD). Aldosterone promoted the proliferative growth of M1-CCD cells, an effect that was protein kinase D1 (PKD1), PKCdelta and ERK1\\/2-dependent. Aldosterone induced the rapid activation of ERK1\\/2 with peaks of activation at 2 and 10 to 30 min after hormone treatment followed by sustained activation lasting beyond 120 min. M1-CCD cells suppressed in PKD1 expression exhibited only the early, transient peaks in ERK1\\/2 activation without the sustained phase. Aldosterone stimulated the physical association of PKD1 with ERK1\\/2 within 2 min of treatment. The mineralocorticoid receptor (MR) antagonist RU28318 inhibited the early and late phases of aldosterone-induced ERK1\\/2 activation, and also aldosterone-induced proliferative cell growth. Aldosterone induced the sub-cellular redistribution of ERK1\\/2 to the nuclei at 2 min and to cytoplasmic sites, proximal to the nuclei after 30 min. This sub-cellular distribution of ERK1\\/2 was inhibited in cells suppressed in the expression of PKD1.

PF-4708671, a specific inhibitor of p70 ribosomal S6 kinase 1, activates Nrf2 by promoting p62-dependent autophagic degradation of Keap1

Energy Technology Data Exchange (ETDEWEB)

Park, Jeong Su [Severance Biomedical Science Institute (Korea, Republic of); Yonsei Biomedical Research Institute, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-752 (Korea, Republic of); Kang, Dong Hoon [Department of Life Science and Ewha Research Center for Systems Biology (Korea, Republic of); The Research Center for Cell Homeostasis, Ewha Womans University, Seoul 127-750 (Korea, Republic of); Lee, Da Hyun [Severance Biomedical Science Institute (Korea, Republic of); Yonsei Biomedical Research Institute, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-752 (Korea, Republic of); Bae, Soo Han, E-mail: soohanbae@yuhs.ac [Severance Biomedical Science Institute (Korea, Republic of); Yonsei Biomedical Research Institute, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-752 (Korea, Republic of)

2015-10-23

p70 ribosomal S6 kinase 1 (S6K1) is an important serine/threonine kinase and downstream target of the mechanistic target of rapamycin complex 1 (mTORC1) signaling pathway. PF-4708671 is a specific inhibitor of S6K1, and prevents S6K1-mediated phosphorylation of the S6 protein. PF-4708671 treatment often leads to apoptotic cell death. However, the protective mechanism against PF-4708671-induced cell death has not been elucidated. The nuclear factor erythroid 2-related factor 2 (Nrf2)-Kelch-like ECH-associated protein 1 (Keap1) pathway is essential for protecting cells against oxidative stress. p62, an adaptor protein in the autophagic process, enhances Nrf2 activation through the impairment of Keap1 activity. In this study, we showed that PF-4708671 induces autophagic Keap1 degradation-mediated Nrf2 activation in p62-dependent manner. Furthermore, p62-dependent Nrf2 activation plays a crucial role in protecting cells from PF-4708671-mediated apoptosis. - Highlights: • PF-4708671, a S6K1-specific inhibitor, prevents S6K1-mediated S6 phosphorylation. • However, PF-4708671 treatment often leads to apoptotic cell death. • Protective mechanism against PF-4708671-induced cell death remains to be elucidated. • PF-4708671 induced p62-dependent, autophagic Keap1 degradation-mediated Nrf2 activation. • p62-dependent Nrf2 activation protects cells from PF-4708671-mediated apoptosis.

Phase relations in crystalline ceramic nuclear waste forms the system UO/sub 2 + x/-CeO2-ZrO2-ThO2 at 12000C in air

International Nuclear Information System (INIS)

Pepin, J.G.; McCarthy, G.J.

1981-01-01

Steady-state phase relations in the system UO/sub 2 + x/-CeO 2 -ZrO 2 -ThO 2 were determined for application to phase relations in the high-level crystalline ceramic nuclear waste form Supercalcine-Ceramics. Samples were treated at 1200 0 C at an oxygen partial pressure of 0.21 atm and a total pressure of 1 atm. Phase assemblages were found to be composed of cubic solid solutions of the flourite structure type, solid solutions based on ZrO 2 , and orthorhombic solid solutions based on U 3 O 8

hnRNP-U is a specific DNA-dependent protein kinase substrate phosphorylated in response to DNA double-strand breaks

International Nuclear Information System (INIS)

Berglund, Fredrik M.; Clarke, Paul R.

2009-01-01

Cellular responses to DNA damage are orchestrated by the large phosphoinositol-3-kinase related kinases ATM, ATR and DNA-PK. We have developed a cell-free system to dissect the biochemical mechanisms of these kinases. Using this system, we identify heterogeneous nuclear ribonucleoprotein U (hnRNP-U), also termed scaffold attachment factor A (SAF-A), as a specific substrate for DNA-PK. We show that hnRNP-U is phosphorylated at Ser59 by DNA-PK in vitro and in cells in response to DNA double-strand breaks. Phosphorylation of hnRNP-U suggests novel functions for DNA-PK in the response to DNA damage.

Nuclear energy related research

International Nuclear Information System (INIS)

Rintamaa, R.

1992-05-01

The annual Research Programme Plan describes publicly funded nuclear energy related research to be carried out mainly at the Technical Research Centre of Finland (VTT) in 1992. The research is financed primarily by the Ministry of Trade and Industry (KTM), the Finnish Centre for Radiation and Nuclear Safety (STUK) and VTT itself. Other research institutes, utilities and industry also contribute to many projects

Nuclear energy related research

International Nuclear Information System (INIS)

Salminen, P.; Mattila, L.

1990-08-01

The annual Research Programme Plan describes the publicly funded nuclear energy related research to be carried out at the Technical Research Centre of Finland (VTT) in 1990. The research is financed primarily by the Ministry of Trade and Industry (KTM), the Finnish Centre for Radiation and Nuclear Safety (STUK) and VTT itself. Utilities and industry also contribute to some projects

Role of ERK1/2 kinase in the expression of iNOS by NDMA in human neutrophils.

Science.gov (United States)

Ratajczak-Wrona, Wioletta; Jablonska, Ewa; Garley, Marzena; Jablonski, Jakub; Radziwon, Piotr

2013-01-01

Potential role of ERK1/2 kinase in conjunction with p38 in the regulation of inducible nitric oxide synthase (iNOS) expression and nitric oxide (NO) production, and superoxide anion generation by human neutrophils (PMNs) exposed to N-nitrosodimethylamine (NDMA) was determined. Increased synthesis of NO due to the involvement of iNOS in neutrophils exposed to NDMA was observed. In addition, intensified activation of ERK1/2 and p38 kinases was determined in these cells. Inhibition of kinase regulated by extracellular signals (ERK1/2) pathway, in contrast to p38 pathway, led to an increased production of NO and expression of iNOS in PMNs. Moreover, as a result of inhibition of ERK1/2 pathway, a decreased activation of p38 kinase was observed in neutrophils, while inhibition of p38 kinase did not affect activation of ERK1/2 pathway in these cells. An increased ability to release superoxide anion by the studied PMNs was observed, which decreased after ERK1/2 pathway inhibition. In conclusion, in human neutrophils, ERK1/2 kinase is not directly involved in the regulation of iNOS and NO production induced by NDMA; however, the kinase participates in superoxide anion production in these cells.

Enterococcus faecalis phosphomevalonate kinase

Science.gov (United States)

Doun, Stephanie S.; Burgner, John W.; Briggs, Scott D.; Rodwell, Victor W.

2005-01-01

The six enzymes of the mevalonate pathway of isopentenyl diphosphate biosynthesis represent potential for addressing a pressing human health concern, the development of antibiotics against resistant strains of the Gram-positive streptococci. We previously characterized the first four of the mevalonate pathway enzymes of Enterococcus faecalis, and here characterize the fifth, phosphomevalonate kinase (E.C. 2.7.4.2). E. faecalis genomic DNA and the polymerase chain reaction were used to clone DNA thought to encode phosphomevalonate kinase into pET28b(+). Double-stranded DNA sequencing verified the sequence of the recombinant gene. The encoded N-terminal hexahistidine-tagged protein was expressed in Escherichia coli with induction by isopropylthiogalactoside and purified by Ni++ affinity chromatography, yield 20 mg protein per liter. Analysis of the purified protein by MALDI-TOF mass spectrometry established it as E. faecalis phosphomevalonate kinase. Analytical ultracentrifugation revealed that the kinase exists in solution primarily as a dimer. Assay for phosphomevalonate kinase activity used pyruvate kinase and lactate dehydrogenase to couple the formation of ADP to the oxidation of NADH. Optimal activity occurred at pH 8.0 and at 37°C. The activation energy was ~5.6 kcal/mol. Activity with Mn++, the preferred cation, was optimal at about 4 mM. Relative rates using different phosphoryl donors were 100 (ATP), 3.6 (GTP), 1.6 (TTP), and 0.4 (CTP). Km values were 0.17 mM for ATP and 0.19 mM for (R,S)-5-phosphomevalonate. The specific activity of the purified enzyme was 3.9 μmol substrate converted per minute per milligram protein. Applications to an immobilized enzyme bioreactor and to drug screening and design are discussed. PMID:15802646

Period1 gates the circadian modulation of memory-relevant signaling in mouse hippocampus by regulating the nuclear shuttling of the CREB kinase pP90RSK.

Science.gov (United States)

Rawashdeh, Oliver; Jilg, Antje; Maronde, Erik; Fahrenkrug, Jan; Stehle, Jörg H

2016-09-01

, sculpturing time-of-day-dependent memory formation. This molecular mechanism constitutes the functional link between circadian rhythms and learning efficiency. In hippocampal neurons of wild-type mice, pP90RSK translocates into the nucleus upon stimulation with forskolin (left), whereas in Period1-knockout (Per1(-/-) ) mice (right) the kinase is trapped at the nuclear periphery, unable to efficiently phosphorylate nuclear CREB. Consequently, the presence of PER1 in hippocampal neurons is a prerequisite for the time-of-day-dependent phosphorylation of CREB, as it regulates the shuttling of pP90RSK into the nucleus. Representative immunofluorescence images show a temporal difference in phosphorylated cAMP response element-binding protein (pCREB; green color) levels in all regions of the dorsal hippocampus between a wild-type C3H mouse (WT; left) and a Period1-knockout (Per1(-/-) ; right) mouse. Images were taken 2 h after lights on, thus, when fluctuating levels of pCREB peak in WT mouse hippocampus. Insets show a representative hippocampal neuron, in response to activating cAMP signaling, stained for the neuronal marker NeuN (red), the nuclear marker DAPI (blue) and the activated CREB kinase pP90RSK (green). The image was taken 2 h after light onset (at the peak of the endogenous CREB phosphorylation that fluctuates with time of day). Magnification: 100X, inset 400X. Read the Editorial Highlight for this article on page 650. Cover image for this issue: doi: 10.1111/jnc.13332. © 2016 International Society for Neurochemistry.

Cloning and sequencing of the casein kinase 2 alpha subunit from Zea mays

DEFF Research Database (Denmark)

Dobrowolska, G; Boldyreff, B; Issinger, O G

1991-01-01

The nucleotide sequence of the cDNA coding for the alpha subunit of casein kinase 2 of Zea mays has been determined. The cDNA clone contains an open reading frame of 996 nucleotides encoding a polypeptide comprising 332 amino acids. The primary amino acid sequence exhibits 75% identity to the alpha...... subunit and 71% identity to the alpha' subunit of human casein kinase 2....

Her4 and Her2/neu tyrosine kinase domains dimerize and activate in a reconstituted in vitro system.

Science.gov (United States)

Monsey, John; Shen, Wei; Schlesinger, Paul; Bose, Ron

2010-03-05

Her4 (ErbB-4) and Her2/neu (ErbB-2) are receptor-tyrosine kinases belonging to the epidermal growth factor receptor (EGFR) family. Crystal structures of EGFR and Her4 kinase domains demonstrate kinase dimerization and activation through an allosteric mechanism. The kinase domains form an asymmetric dimer, where the C-lobe surface of one monomer contacts the N-lobe of the other monomer. EGFR kinase dimerization and activation in vitro was previously reported using a nickel-chelating lipid-liposome system, and we now apply this system to all other members of the EGFR family. Polyhistidine-tagged Her4, Her2/neu, and Her3 kinase domains are bound to these nickel-liposomes and are brought to high local concentration, mimicking what happens to full-length receptors in vivo following ligand binding. Addition of nickel-liposomes to Her4 kinase domain results in 40-fold activation in kinase activity and marked enhancement of C-terminal tail autophosphorylation. Activation of Her4 shows a sigmoidal dependence on kinase concentration, consistent with a cooperative process requiring kinase dimerization. Her2/neu kinase activity is also activated by nickel-liposomes, and is increased further by heterodimerization with Her3 or Her4. The ability of Her3 and Her4 to heterodimerize and activate other family members is studied in vitro. Her3 kinase domain readily activates Her2/neu but is a poor activator of Her4, which differs from the prediction made by the asymmetric dimer model. Mutation of Her3 residues (952)ENI(954) to the corresponding sequence in Her4 enhanced the ability of Her3 to activate Her4, demonstrating that sequence differences on the C-lobe surface influence the heterodimerization and activation of ErbB kinase domains.

R2 Combined Statistical Area (CSA), 2013; TIGER/Line Shapefile

Data.gov (United States)

U.S. Environmental Protection Agency — The TIGER/Line shapefiles and related database files (.dbf) are an extract of selected geographic and cartographic information from the U.S. Census Bureau's Master...

Nuclear energy related research

International Nuclear Information System (INIS)

Mattila, L.; Vanttola, T.

1991-10-01

The annual Research Programme Plan describes the publicly funded nuclear energy related research to be carried out mainly at the Technical Research Centre of Finland (VTT) in 1991. The research is financed primarily by the Ministry of Trade and Industry (KTM), the Finnish Centre for Radiation and Nuclear Safety (STUK) and VTT itself. Other research institutes, utilities and industry also contribute to many projects

CDKL5 influences RNA splicing activity by its association to the nuclear speckle molecular machinery.

Science.gov (United States)

Ricciardi, Sara; Kilstrup-Nielsen, Charlotte; Bienvenu, Thierry; Jacquette, Aurélia; Landsberger, Nicoletta; Broccoli, Vania

2009-12-01

Mutations in the human X-linked cyclin-dependent kinase-like 5 (CDKL5) gene have been shown to cause severe neurodevelopmental disorders including infantile spasms, encephalopathy, West-syndrome and an early-onset variant of Rett syndrome. CDKL5 is a serine/threonine kinase whose involvement in Rett syndrome can be inferred by its ability to directly bind and mediate phosphorylation of MeCP2. However, it remains to be elucidated how CDKL5 exerts its function. Here, we report that CDKL5 localizes to specific nuclear foci referred to as nuclear speckles in both cell lines and tissues. These sub-nuclear structures are traditionally considered as storage/modification sites of pre-mRNA splicing factors. Interestingly, we provide evidence that CDKL5 regulates the dynamic behaviour of nuclear speckles. Indeed, CDKL5 overexpression leads to nuclear speckle disassembly, and this event is strictly dependent on its kinase activity. Conversely, its down-regulation affects nuclear speckle morphology leading to abnormally large and uneven speckles. Similar results were obtained for primary adult fibroblasts isolated from CDKL5-mutated patients. Altogether, these findings indicate that CDKL5 controls nuclear speckle morphology probably by regulating the phosphorylation state of splicing regulatory proteins. Nuclear speckles are dynamic sites that can continuously supply splicing factors to active transcription sites, where splicing occurs. Notably, we proved that CDKL5 influences alternative splicing, at least as proved in heterologous minigene assays. In conclusion, we provide evidence that CDKL5 is involved indirectly in pre-mRNA processing, by controlling splicing factor dynamics. These findings identify a biological process whose disregulation might affect neuronal maturation and activity in CDKL5-related disorders.

The JH2 domain and SH2-JH2 linker regulate JAK2 activity: A detailed kinetic analysis of wild type and V617F mutant kinase domains.

Science.gov (United States)

Sanz Sanz, Arturo; Niranjan, Yashavanthi; Hammarén, Henrik; Ungureanu, Daniela; Ruijtenbeek, Rob; Touw, Ivo P; Silvennoinen, Olli; Hilhorst, Riet

2014-10-01

JAK2 tyrosine kinase regulates many cellular functions. Its activity is controlled by the pseudokinase (JH2) domain by still poorly understood mechanisms. The V617F mutation in the pseudokinase domain activates JAK2 and causes myeloproliferative neoplasms. We conducted a detailed kinetic analysis of recombinant JAK2 tyrosine kinase domain (JH1) and wild-type and V617F tandem kinase (JH1JH2) domains using peptide microarrays to define the functions of the kinase domains. The results show that i) JAK2 follows a random Bi-Bi reaction mechanism ii) JH2 domain restrains the activity of the JH1 domain by reducing the affinity for ATP and ATP competitive inhibitors iii) V617F decreases affinity for ATP but increases catalytic activity compared to wild-type and iv) the SH2-JH2 linker region participates in controlling activity by reducing the affinity for ATP. Copyright © 2014 Elsevier B.V. All rights reserved.

Akt-dependent Activation of the Heart 6-Phosphofructo-2-kinase/Fructose-2,6-bisphosphatase (PFKFB2) Isoenzyme by Amino Acids*

Science.gov (United States)

Novellasdemunt, Laura; Tato, Irantzu; Navarro-Sabate, Aurea; Ruiz-Meana, Marisol; Méndez-Lucas, Andrés; Perales, Jose Carlos; Garcia-Dorado, David; Ventura, Francesc; Bartrons, Ramon; Rosa, Jose Luis

2013-01-01

Reciprocal regulation of metabolism and signaling allows cells to modulate their activity in accordance with their metabolic resources. Thus, amino acids could activate signal transduction pathways that control cell metabolism. To test this hypothesis, we analyzed the effect of amino acids on fructose-2,6-bisphosphate (Fru-2,6-P2) metabolism. We demonstrate that amino acids increase Fru-2,6-P2 concentration in HeLa and in MCF7 human cells. In conjunction with this, 6-phosphofructo-2-kinase activity, glucose uptake, and lactate concentration were increased. These data correlate with the specific phosphorylation of heart 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase (PFKFB2) isoenzyme at Ser-483. This activation was mediated by the PI3K and p38 signaling pathways. Furthermore, Akt inactivation blocked PFKFB2 phosphorylation and Fru-2,6-P2 production, thereby suggesting that the above signaling pathways converge at Akt kinase. In accordance with these results, kinase assays showed that amino acid-activated Akt phosphorylated PFKFB2 at Ser-483 and that knockdown experiments confirmed that the increase in Fru-2,6-P2 concentration induced by amino acids was due to PFKFB2. In addition, similar effects on Fru-2,6-P2 metabolism were observed in freshly isolated rat cardiomyocytes treated with amino acids, which indicates that these effects are not restricted to human cancer cells. In these cardiomyocytes, the glucose consumption and the production of lactate and ATP suggest an increase of glycolytic flux. Taken together, these results demonstrate that amino acids stimulate Fru-2,6-P2 synthesis by Akt-dependent PFKFB2 phosphorylation and activation and show how signaling and metabolism are inextricably linked. PMID:23457334

Nuclear data and related services

International Nuclear Information System (INIS)

Tuli, J.K.

1985-01-01

National Nuclear Data Center (NNDC) maintains a number of data bases containing bibliographic information and evaluated as well as experimental nuclear properties. An evaluated computer file maintained by the NNDC, called the Evaluated Nuclear Structure Data File (ENSDF), contains nuclear structure information for all known nuclides. The ENSDF is the source for the journal Nuclear Data Sheets which is produced and edited by NNDC. The Evaluated Nuclear Data File (ENDF), on the other hand is designed for storage and retrieval of such evaluated nuclear data as are used in neutronic, photonic, and decay heat calculations in a large variety of applications. The NNDC maintains three bibliographic files: NSR - for nuclear structure and decay data related references, CINDA - a bibliographic file for neutron induced reactions, and CPBIB - for charged particle reactions. Selected retrievals from evaluated data and bibliographic files are possible on-line or on request from NNDC

Photoactivatable Caged Prodrugs of VEGFR-2 Kinase Inhibitors

OpenAIRE

Boris Pinchuk; Rebecca Horbert; Alexander Döbber; Lydia Kuhl; Christian Peifer

2016-01-01

In this study, we report on the design, synthesis, photokinetic properties and in vitro evaluation of photoactivatable caged prodrugs for the receptor tyrosine kinase VEGFR-2. Highly potent VEGFR-2 inhibitors 1 and 3 were caged by introduction of a photoremovable protecting group (PPG) to yield the caged prodrugs 4 and 5. As expected, enzymatic and cellular proliferation assays showed dramatically diminished efficacy of caged prodrugs in vitro. Upon ultraviolet (UV) irradiation of the prodrug...

HSP90 inhibitors potentiate PGF2α-induced IL-6 synthesis via p38 MAP kinase in osteoblasts.

Directory of Open Access Journals (Sweden)

Kazuhiko Fujita

Full Text Available Heat shock protein 90 (HSP90 that is ubiquitously expressed in various tissues, is recognized to be a major molecular chaperone. We have previously reported that prostaglandin F2α (PGF2α, a potent bone remodeling mediator, stimulates the synthesis of interleukin-6 (IL-6 through p44/p42 mitogen-activated protein (MAP kinase and p38 MAP kinase in osteoblast-like MC3T3-E1 cells, and that Rho-kinase acts at a point upstream of p38 MAP kinase. In the present study, we investigated the involvement of HSP90 in the PGF2α-stimulated IL-6 synthesis and the underlying mechanism in MC3T3-E1 cells. Geldanamycin, an inhibitor of HSP90, significantly amplified both the PGF2α-stimulated IL-6 release and the mRNA expression levels. In addition, other HSP90 inhibitors, 17-allylamino-17demethoxy-geldanamycin (17-AAG and 17-dimethylamino-ethylamino-17-demethoxy-geldanamycin (17-DMAG and onalespib, enhanced the PGF2α-stimulated IL-6 release. Geldanamycin, 17-AAG and onalespib markedly strengthened the PGF2α-induced phosphorylation of p38 MAP kinase. Geldanamycin and 17-AAG did not affect the PGF2α-induced phosphorylation of p44/p42 MAP kinase and myosin phosphatase targeting subunit (MYPT-1, a substrate of Rho-kinase, and the protein levels of RhoA and Rho-kinase. In addition, HSP90-siRNA enhanced the PGF2α-induced phosphorylation of p38 MAP kinase. Furthermore, SB203580, an inhibitor of p38 MAP kinase, significantly suppressed the amplification by geldanamycin, 17-AAG or 17-DMAG of the PGF2α-stimulated IL-6 release. Our results strongly suggest that HSP90 negatively regulates the PGF2α-stimulated IL-6 synthesis in osteoblasts, and that the effect of HSP90 is exerted through regulating p38 MAP kinase activation.

Role of nongenomic activation of phosphatidylinositol 3-kinase/Akt and mitogen-activated protein kinase/extracellular signal-regulated kinase kinase/extracellular signal-regulated kinase 1/2 pathways in 1,25D3-mediated apoptosis in squamous cell carcinoma cells.

Science.gov (United States)

Ma, Yingyu; Yu, Wei-Dong; Kong, Rui-Xian; Trump, Donald L; Johnson, Candace S

2006-08-15

Vitamin D is a steroid hormone that regulates calcium homeostasis and bone metabolism. The active form of vitamin D [1 alpha,25-dihydroxyvitamin D(3) (1,25D3)] acts through both genomic and nongenomic pathways. 1,25D3 has antitumor effects in a variety of cancers, including colorectal, prostate, breast, ovarian, and skin cancers. 1,25D3 exerts growth-inhibitory effects in cancer cells through the induction of apoptosis, cell cycle arrest, and differentiation. The mechanisms regulating 1,25D3-induced apoptosis remain unclear. We investigated the role of nongenomic signaling in 1,25D3-mediated apoptosis in squamous cell carcinoma (SCC) cells. 1,25D3 induced rapid and sustained activation of phosphatidylinositol 3-kinase/Akt and mitogen-activated protein kinase/extracellular signal-regulated kinase (ERK) 1/2 pathways in SCC cells. These effects were nongenomic: they occurred rapidly and were not inhibited by cycloheximide or actinomycin D. To examine whether the nongenomic activation of Akt and ERK1/2 plays a role in 1,25D3-mediated apoptosis, the expression of Akt or ERK1/2 was reduced by small interfering RNA (siRNA). siRNA-Akt significantly enhanced 1,25D3-induced apoptosis as indicated by increased levels of Annexin V-positive cells and increased sub-G(1) population and DNA fragmentation. In contrast, siRNA-ERK1/2 had no effects on 1,25D3-induced apoptosis. In addition, siRNA-Akt transfection followed by 1,25D3 treatment induced apoptosis much sooner than 1,25D3 alone. siRNA-Akt and 1,25D3 induced caspase-10 activation, suppressed the expression of c-IAP1 and XIAP, and promoted 1,25D3-induced caspase-3 activation. These results support a link between 1,25D3-induced nongenomic signaling and apoptosis. 1,25D3 induces the activation of phosphatidylinositol 3-kinase/Akt, which suppresses 1,25D3-mediated apoptosis and prolongs the survival of SCC cells.

Protein phosphatases active on acetyl-CoA carboxylase phosphorylated by casein kinase I, casein kinase II and the cAMP-dependent protein kinase

International Nuclear Information System (INIS)