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Sung H, Hyland PL, Pemov A, Sabourin JA, Baldwin AM, Bass S, Teshome K, Luo W, Widemann BC, Stewart DR, Wilson AF. Genome-wide association study of café-au-lait macule number in neurofibromatosis type 1. Mol Genet Genomic Med 2020; 8:e1400. [PMID: 32869517 PMCID: PMC7549607 DOI: 10.1002/mgg3.1400] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 05/28/2020] [Indexed: 12/11/2022] Open
Abstract
Background Neurofibromatosis type 1 (NF1) is a tumor‐predisposition disorder that arises due to pathogenic variants in tumor suppressor NF1. NF1 has variable expressivity that may be due, at least in part, from heritable elements such as modifier genes; however, few genetic modifiers have been identified to date. Methods In this study, we performed a genome‐wide association analysis of the number of café‐au‐lait macules (CALM) that are considered a tumor‐like trait as a clinical phenotype modifying NF1. Results A borderline genome‐wide significant association was identified in the discovery cohort (CALM1, N = 112) between CALM number and rs12190451 (and rs3799603, r2 = 1.0; p = 7.4 × 10−8) in the intronic region of RPS6KA2. Although, this association was not replicated in the second cohort (CALM2, N = 59) and a meta‐analysis did not show significantly associated variants in this region, a significant corroboration score (0.72) was obtained for the RPS6KA2 signal in the discovery cohort (CALM1) using Complementary Pairs Stability Selection for Genome‐Wide Association Studies (ComPaSS‐GWAS) analysis, suggesting that the lack of replication may be due to heterogeneity of the cohorts rather than type I error. Conclusion rs12190451 is located in a melanocyte‐specific enhancer and may influence RPS6KA2 expression in melanocytes—warranting further functional studies.
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Affiliation(s)
- Heejong Sung
- Genometrics Section, Computational and Statistical Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Baltimore, MD, USA
| | - Paula L Hyland
- Integrative Tumor Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD, USA.,Division of Applied Regulatory Science, Office of Translational Science, Center for Drug Evaluation & Research, U.S. Food and Drug Administration, Silver Spring, MD, USA
| | - Alexander Pemov
- Clinical Genetics Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD, USA
| | - Jeremy A Sabourin
- Genometrics Section, Computational and Statistical Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Baltimore, MD, USA
| | - Andrea M Baldwin
- Pediatric Oncology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Sara Bass
- Frederick National Laboratory for Cancer Research, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD, USA
| | - Kedest Teshome
- Frederick National Laboratory for Cancer Research, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD, USA
| | - Wen Luo
- Frederick National Laboratory for Cancer Research, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD, USA
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- Frederick National Laboratory for Cancer Research, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD, USA
| | - Brigitte C Widemann
- Pediatric Oncology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Douglas R Stewart
- Clinical Genetics Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD, USA
| | - Alexander F Wilson
- Genometrics Section, Computational and Statistical Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Baltimore, MD, USA
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2
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Torres-Quesada O, Mayrhofer JE, Stefan E. The many faces of compartmentalized PKA signalosomes. Cell Signal 2017; 37:1-11. [PMID: 28528970 DOI: 10.1016/j.cellsig.2017.05.012] [Citation(s) in RCA: 131] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 05/16/2017] [Accepted: 05/17/2017] [Indexed: 01/03/2023]
Abstract
Cellular signal transmission requires the dynamic formation of spatiotemporally controlled molecular interactions. At the cell surface information is received by receptor complexes and relayed through intracellular signaling platforms which organize the actions of functionally interacting signaling enzymes and substrates. The list of hormone or neurotransmitter pathways that utilize the ubiquitous cAMP-sensing protein kinase A (PKA) system is expansive. This requires that the specificity, duration, and intensity of PKA responses are spatially and temporally restricted. Hereby, scaffolding proteins take the center stage for ensuring proper signal transmission. They unite second messenger sensors, activators, effectors, and kinase substrates within cellular micro-domains to precisely control and route signal propagation. A-kinase anchoring proteins (AKAPs) organize such subcellular signalosomes by tethering the PKA holoenzyme to distinct cell compartments. AKAPs differ in their modular organization showing pathway specific arrangements of interaction motifs or domains. This enables the cell- and compartment- guided assembly of signalosomes with unique enzyme composition and function. The AKAP-mediated clustering of cAMP and other second messenger sensing and interacting signaling components along with functional successive enzymes facilitates the rapid and precise dissemination of incoming signals. This review article delineates examples for different means of PKA regulation and for snapshots of compartmentalized PKA signalosomes.
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Affiliation(s)
- Omar Torres-Quesada
- Institute of Biochemistry and Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria
| | - Johanna E Mayrhofer
- Institute of Biochemistry and Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria
| | - Eduard Stefan
- Institute of Biochemistry and Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria.
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3
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Ivan T, Enkvist E, Viira B, Manoharan GB, Raidaru G, Pflug A, Alam KA, Zaccolo M, Engh RA, Uri A. Bifunctional Ligands for Inhibition of Tight-Binding Protein-Protein Interactions. Bioconjug Chem 2016; 27:1900-10. [PMID: 27389935 DOI: 10.1021/acs.bioconjchem.6b00293] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The acknowledged potential of small-molecule therapeutics targeting disease-related protein-protein interactions (PPIs) has promoted active research in this field. The strategy of using small molecule inhibitors (SMIs) to fight strong (tight-binding) PPIs tends to fall short due to the flat and wide interfaces of PPIs. Here we propose a biligand approach for disruption of strong PPIs. The potential of this approach was realized for disruption of the tight-binding (KD = 100 pM) tetrameric holoenzyme of cAMP-dependent protein kinase (PKA). Supported by X-ray analysis of cocrystals, bifunctional inhibitors (ARC-inhibitors) were constructed that simultaneously associated with both the ATP-pocket and the PPI interface area of the catalytic subunit of PKA (PKAc). Bifunctional inhibitor ARC-1411, possessing a KD value of 3 pM toward PKAc, induced the dissociation of the PKA holoenzyme with a low-nanomolar IC50, whereas the ATP-competitive inhibitor H89 bound to the PKA holoenzyme without disruption of the protein tetramer.
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Affiliation(s)
- Taavi Ivan
- Institute of Chemistry, University of Tartu , 50410 Tartu, Estonia
| | - Erki Enkvist
- Institute of Chemistry, University of Tartu , 50410 Tartu, Estonia
| | - Birgit Viira
- Institute of Chemistry, University of Tartu , 50410 Tartu, Estonia
| | | | - Gerda Raidaru
- Institute of Chemistry, University of Tartu , 50410 Tartu, Estonia
| | - Alexander Pflug
- The Norwegian Structural Biology Centre, Department of Chemistry, University of Tromsø , N-9019 Tromsø, Norway
| | - Kazi Asraful Alam
- The Norwegian Structural Biology Centre, Department of Chemistry, University of Tromsø , N-9019 Tromsø, Norway
| | - Manuela Zaccolo
- Department of Physiology, Anatomy and Genetics, University of Oxford , OX1 3QX Oxford, United Kingdom
| | - Richard Alan Engh
- The Norwegian Structural Biology Centre, Department of Chemistry, University of Tromsø , N-9019 Tromsø, Norway
| | - Asko Uri
- Institute of Chemistry, University of Tartu , 50410 Tartu, Estonia
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4
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Biswas NK, Chandra V, Sarkar-Roy N, Das T, Bhattacharya RN, Tripathy LN, Basu SK, Kumar S, Das S, Chatterjee A, Mukherjee A, Basu P, Maitra A, Chattopadhyay A, Basu A, Dhara S. Variant allele frequency enrichment analysis in vitro reveals sonic hedgehog pathway to impede sustained temozolomide response in GBM. Sci Rep 2015; 5:7915. [PMID: 25604826 PMCID: PMC4300501 DOI: 10.1038/srep07915] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Accepted: 12/22/2014] [Indexed: 01/06/2023] Open
Abstract
Neoplastic cells of Glioblastoma multiforme (GBM) may or may not show sustained response to temozolomide (TMZ) chemotherapy. We hypothesize that TMZ chemotherapy response in GBM is predetermined in its neoplastic clones via a specific set of mutations that alter relevant pathways. We describe exome-wide enrichment of variant allele frequencies (VAFs) in neurospheres displaying contrasting phenotypes of sustained versus reversible TMZ-responses in vitro. Enrichment of VAFs was found on genes ST5, RP6KA1 and PRKDC in cells showing sustained TMZ-effect whereas on genes FREM2, AASDH and STK36, in cells showing reversible TMZ-effect. Ingenuity pathway analysis (IPA) revealed that these genes alter cell-cycle, G2/M-checkpoint-regulation and NHEJ pathways in sustained TMZ-effect cells whereas the lysine-II&V/phenylalanine degradation and sonic hedgehog (Hh) pathways in reversible TMZ-effect cells. Next, we validated the likely involvement of the Hh-pathway in TMZ-response on additional GBM neurospheres as well as on GBM patients, by extracting RNA-sequencing-based gene expression data from the TCGA-GBM database. Finally, we demonstrated TMZ-sensitization of a TMZ non-responder neurosphere in vitro by treating them with the FDA-approved pharmacological Hh-pathway inhibitor vismodegib. Altogether, our results indicate that the Hh-pathway impedes sustained TMZ-response in GBM and could be a potential therapeutic target to enhance TMZ-response in this malignancy.
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Affiliation(s)
- Nidhan K Biswas
- National Institute of Biomedical Genomics, Kalyani, West Bengal 741251, India
| | - Vikas Chandra
- National Institute of Biomedical Genomics, Kalyani, West Bengal 741251, India
| | - Neeta Sarkar-Roy
- National Institute of Biomedical Genomics, Kalyani, West Bengal 741251, India
| | - Tapojyoti Das
- National Institute of Biomedical Genomics, Kalyani, West Bengal 741251, India
| | | | - Laxmi N Tripathy
- Medica Superspeciality Hospital, 127 Mukundapur, Kolkata 700099, India
| | - Sunandan K Basu
- Medica Superspeciality Hospital, 127 Mukundapur, Kolkata 700099, India
| | - Shantanu Kumar
- National Institute of Biomedical Genomics, Kalyani, West Bengal 741251, India
| | - Subrata Das
- National Institute of Biomedical Genomics, Kalyani, West Bengal 741251, India
| | - Ankita Chatterjee
- National Institute of Biomedical Genomics, Kalyani, West Bengal 741251, India
| | - Ankur Mukherjee
- National Institute of Biomedical Genomics, Kalyani, West Bengal 741251, India
| | - Pryiadarshi Basu
- National Institute of Biomedical Genomics, Kalyani, West Bengal 741251, India
| | - Arindam Maitra
- National Institute of Biomedical Genomics, Kalyani, West Bengal 741251, India
| | | | - Analabha Basu
- National Institute of Biomedical Genomics, Kalyani, West Bengal 741251, India
| | - Surajit Dhara
- National Institute of Biomedical Genomics, Kalyani, West Bengal 741251, India
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5
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Toruno C, Carbonneau S, Stewart RA, Jette C. Interdependence of Bad and Puma during ionizing-radiation-induced apoptosis. PLoS One 2014; 9:e88151. [PMID: 24516599 PMCID: PMC3916415 DOI: 10.1371/journal.pone.0088151] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Accepted: 01/05/2014] [Indexed: 11/19/2022] Open
Abstract
Ionizing radiation (IR)-induced DNA double-strand breaks trigger an extensive cellular signaling response that involves the coordination of hundreds of proteins to regulate DNA repair, cell cycle arrest and apoptotic pathways. The cellular outcome often depends on the level of DNA damage as well as the particular cell type. Proliferating zebrafish embryonic neurons are highly sensitive to IR-induced apoptosis, and both p53 and its transcriptional target puma are essential mediators of the response. The BH3-only protein Puma has previously been reported to activate mitochondrial apoptosis through direct interaction with the pro-apoptotic Bcl-2 family proteins Bax and Bak, thus constituting the role of an “activator” BH3-only protein. This distinguishes it from BH3-only proteins like Bad that are thought to indirectly promote apoptosis through binding to anti-apoptotic Bcl-2 family members, thereby preventing the sequestration of activator BH3-only proteins and allowing them to directly interact with and activate Bax and Bak. We have shown previously that overexpression of the BH3-only protein Bad in zebrafish embryos supports normal embryonic development but greatly sensitizes developing neurons to IR-induced apoptosis. While Bad has previously been shown to play only a minor role in promoting IR-induced apoptosis of T cells in mice, we demonstrate that Bad is essential for robust IR-induced apoptosis in zebrafish embryonic neural tissue. Moreover, we found that both p53 and Puma are required for Bad-mediated radiosensitization in vivo. Our findings show the existence of a hierarchical interdependence between Bad and Puma whereby Bad functions as an essential sensitizer and Puma as an essential activator of IR-induced mitochondrial apoptosis specifically in embryonic neural tissue.
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Affiliation(s)
- Cristhian Toruno
- Department of Oncological Sciences, Huntsman Cancer Institute, University of Utah, Salt Lake City, Utah, United States of America
| | - Seth Carbonneau
- Department of Pediatric Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, Massachusetts, United States of America
| | - Rodney A. Stewart
- Department of Oncological Sciences, Huntsman Cancer Institute, University of Utah, Salt Lake City, Utah, United States of America
| | - Cicely Jette
- Department of Oncological Sciences, Huntsman Cancer Institute, University of Utah, Salt Lake City, Utah, United States of America
- * E-mail:
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6
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Paxillin phosphorylation counteracts proteoglycan-mediated inhibition of axon regeneration. Exp Neurol 2013; 248:157-69. [PMID: 23797153 DOI: 10.1016/j.expneurol.2013.06.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Revised: 05/29/2013] [Accepted: 06/14/2013] [Indexed: 11/21/2022]
Abstract
In the adult central nervous system, the tips of axons severed by injury are commonly transformed into dystrophic endballs and cease migration upon encountering a rising concentration gradient of inhibitory proteoglycans. However, intracellular signaling networks mediating endball migration failure remain largely unknown. Here we show that manipulation of protein kinase A (PKA) or its downstream adhesion component paxillin can reactivate the locomotive machinery of endballs in vitro and facilitate axon growth after injury in vivo. In dissociated cultures of adult rat dorsal root ganglion neurons, PKA is activated in endballs formed on gradients of the inhibitory proteoglycan aggrecan, and pharmacological inhibition of PKA promotes axon growth on aggrecan gradients most likely through phosphorylation of paxillin at serine 301. Remarkably, pre-formed endballs on aggrecan gradients resume forward migration in response to PKA inhibition. This resumption of endball migration is associated with increased turnover of adhesive point contacts dependent upon paxillin phosphorylation. Furthermore, expression of phosphomimetic paxillin overcomes aggrecan-mediated growth arrest of endballs, and facilitates axon growth after optic nerve crush in vivo. These results point to the importance of adhesion dynamics in restoring endball migration and suggest a potential therapeutic target for axon tract repair.
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7
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cAMP-elevation mediated by β-adrenergic stimulation inhibits salt-inducible kinase (SIK) 3 activity in adipocytes. Cell Signal 2012; 24:1863-71. [PMID: 22588126 DOI: 10.1016/j.cellsig.2012.05.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2012] [Accepted: 05/06/2012] [Indexed: 11/22/2022]
Abstract
Salt-inducible kinase (SIK) 3 is a virtually unstudied, ubiquitously expressed serine/threonine kinase, belonging to the AMP-activated protein kinase (AMPK)-related family of kinases, all of which are regulated by LKB1 phosphorylation of a threonine residue in their activation (T)-loops. Findings in adrenal cells have revealed a role for cAMP in the regulation of SIK1, and recent findings suggest that insulin can regulate an SIK isoform in Drosophila. As cAMP has important functions in adipocytes, mainly in the regulation of lipolysis, we have evaluated a potential role for cAMP, as well as for insulin, in the regulation of SIK3 in these cells. We establish that raised cAMP levels in response to forskolin and the β-adrenergic receptor agonist CL 316,243 induce a phosphorylation of SIK3 in HEK293 cells and primary adipocytes. This phosphorylation coincides with increased 14-3-3 binding to SIK3 in these cell types. Our findings also show that cAMP-elevation results in reduced SIK3 activity in adipocytes. Phosphopeptide mapping and site-directed mutagenesis reveal that the cAMP-mediated regulation of SIK3 appears to depend on three residues, T469, S551 and S674, that all contribute to some extent to the cAMP-induced phosphorylation and 14-3-3-binding. As the cAMP-induced regulation can be reversed with the protein kinase A (PKA) inhibitor H89, and a role for other candidate kinases, including PKB and RSK, could be excluded, we believe that PKA is the kinase responsible for SIK3 regulation in response to elevated cAMP levels. Our findings of cAMP-mediated regulation of SIK3 suggest that SIK3 may mediate some of the effects of this important second messenger in adipocytes.
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8
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Hundsrucker C, Skroblin P, Christian F, Zenn HM, Popara V, Joshi M, Eichhorst J, Wiesner B, Herberg FW, Reif B, Rosenthal W, Klussmann E. Glycogen synthase kinase 3beta interaction protein functions as an A-kinase anchoring protein. J Biol Chem 2009; 285:5507-21. [PMID: 20007971 DOI: 10.1074/jbc.m109.047944] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
A-kinase anchoring proteins (AKAPs) include a family of scaffolding proteins that target protein kinase A (PKA) and other signaling proteins to cellular compartments and thereby confine the activities of the associated proteins to distinct regions within cells. AKAPs bind PKA directly. The interaction is mediated by the dimerization and docking domain of regulatory subunits of PKA and the PKA-binding domain of AKAPs. Analysis of the interactions between the dimerization and docking domain and various PKA-binding domains yielded a generalized motif allowing the identification of AKAPs. Our bioinformatics and peptide array screening approaches based on this signature motif identified GSKIP (glycogen synthase kinase 3beta interaction protein) as an AKAP. GSKIP directly interacts with PKA and GSK3beta (glycogen synthase kinase 3beta). It is widely expressed and facilitates phosphorylation and thus inactivation of GSK3beta by PKA. GSKIP contains the evolutionarily conserved domain of unknown function 727. We show here that this domain of GSKIP and its vertebrate orthologues binds both PKA and GSK3beta and thereby provides a mechanism for the integration of PKA and GSK3beta signaling pathways.
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Affiliation(s)
- Christian Hundsrucker
- Leibniz Institute for Molecular Pharmacology, Robert-Rössle-Strasse 10, 13125 Berlin, Germany
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9
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Abstract
The BH3-only pro-apoptotic proteins are upstream sensors of cellular damage that selectively respond to specific, proximal death and survival signals. Genetic models and biochemical studies indicate that these molecules are latent killers until activated through transcriptional or post-translational mechanisms in a tissue-restricted and signal-specific manner. The large number of BH3-only proteins, their unique subcellular localization, protein-interaction network and diverse modes of activation suggest specialization of their damage-sensing function, ensuring that the core apoptotic machinery is poised to receive input from a wide range of cellular stress signals. The apoptotic response initiated by the activation of BH3-only proteins ultimately culminates in allosteric activation of pro-apoptotic BAX and BAK, the gateway proteins to the mitochondrial pathway of apoptosis. From activation of BH3-only proteins to oligomerization of BAX and BAK and mitochondrial outer membrane permeabilization, an intricate network of interactions between the pro- and anti-apoptotic members of the BCL-2 family orchestrates the decision to undergo apoptosis. Beyond regulation of apoptosis, multiple BCL-2 proteins have recently emerged as active components of select homeostatic pathways carrying other cellular functions. This review focuses on BAD, which was the first BH3-only protein linked to proximal survival signals through phosphorylation by survival kinases. In addition to findings that delineated the physiological role of BAD in apoptosis and its dynamic regulation by phosphorylation, studies pointing to new roles for this protein in other physiological pathways, such as glucose metabolism, are highlighted. By executing its 'day' and 'night' jobs in metabolism and apoptosis, respectively, BAD helps coordinate mitochondrial fuel metabolism and the apoptotic machinery.
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10
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McCahill AC, Huston E, Li X, Houslay MD. PDE4 associates with different scaffolding proteins: modulating interactions as treatment for certain diseases. Handb Exp Pharmacol 2008:125-66. [PMID: 18491051 DOI: 10.1007/978-3-540-72843-6_6] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
cAMP is an ubiquitous second messenger that is crucial to many cellular processes. The sole means of terminating the cAMP signal is degradation by cAMP phosphodiesterases (PDEs). The PDE4 family is of particular interest because PDE4 inhibitors have therapeutic potential for the treatment of various inflammatory and auto-immune diseases and also have anti-depressant and memory-enhancing effects. The subcellular targeting of PDE4 isoforms is fundamental to the compartmentalization of cAMP signaling pathways and is largely achieved via proteinprotein interactions. Increased knowledge of these protein-protein interactions and their regulatory properties could aid in the design of novel isoform-specific inhibitors with improved efficacy and fewer prohibitive side effects.
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Affiliation(s)
- A C McCahill
- Molecular Pharmacology Group, Division of Biochemistry and Molecular Biology, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow, G128QQ, UK
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11
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Le phospho-FACS : un outil puissant d’exploration des cascades de transduction intracellulaires. Rev Mal Respir 2007; 24:955-64. [DOI: 10.1016/s0761-8425(07)92761-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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12
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Deree J, Melbostad H, Loomis WH, Putnam JG, Coimbra R. The effects of a novel resuscitation strategy combining pentoxifylline and hypertonic saline on neutrophil MAPK signaling. Surgery 2007; 142:276-83. [PMID: 17689696 DOI: 10.1016/j.surg.2007.04.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2007] [Revised: 04/19/2007] [Accepted: 04/20/2007] [Indexed: 11/24/2022]
Abstract
BACKGROUND The combination of hypertonic saline (HS) and pentoxifylline (PTX) has been shown to synergistically downregulate neutrophil oxidative burst in vitro. We investigated the effects of HS/PTX on human neutrophil mitogen-activated protein kinase (MAPK) signaling and the role of Protein kinase A (PKA) in this process. METHODS Isolated neutrophils were treated with PTX (2 mmol/L), HS10 (10 mmol/L above isotonicity), and HS40 (40 mmol/L above isotonicity) alone or in combination for determination of intracellular cyclic adenosine monophosphate (cAMP) concentrations. Human neutrophils were stimulated with f-methionyl-leucyl-phenylalanine (fMLP) (1 micromol/L) before the treatments above in both the presence and the absence of PKA inhibition for Western blot analysis of MAPK p38 and extracellular signal-related kinase 1/2 (ERK 1/2) phosphorylation. RESULTS Concomitant exposure to HS/PTX results in an additive increase in intracellular cAMP. fMLP-induced ERK 1/2 phosphorylation was synergistically attenuated by HS/PTX. Both PTX and HS reduced p38MAPK phosphorylation. No additive effect was observed with combined treatment. Although PKA inhibition abrogated the effects of PTX, HS retained some capacity to attenuate MAPK phosphorylation. CONCLUSION HS/PTX is more effective in attenuating neutrophil ERK signaling than either component alone, whereas both components alone or in combination produced comparable results with p38MAPK. Although PTX functions primarily through PKA activation, HS may suppress neutrophils through a partially PKA-independent mechanism.
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Affiliation(s)
- Jessica Deree
- Division of Trauma and Surgical Critical Care, Department of Surgery, University of California San Diego School of Medicine, San Diego, Calif, USA
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13
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Kesavapany S, Patel V, Zheng YL, Pareek TK, Bjelogrlic M, Albers W, Amin N, Jaffe H, Gutkind JS, Strong MJ, Grant P, Pant HC. Inhibition of Pin1 reduces glutamate-induced perikaryal accumulation of phosphorylated neurofilament-H in neurons. Mol Biol Cell 2007; 18:3645-55. [PMID: 17626162 PMCID: PMC1951754 DOI: 10.1091/mbc.e07-03-0237] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Under normal conditions, the proline-directed serine/threonine residues of neurofilament tail-domain repeats are exclusively phosphorylated in axons. In pathological conditions such as amyotrophic lateral sclerosis (ALS), motor neurons contain abnormal perikaryal accumulations of phosphorylated neurofilament proteins. The precise mechanisms for this compartment-specific phosphorylation of neurofilaments are not completely understood. Although localization of kinases and phosphatases is certainly implicated, another possibility involves Pin1 modulation of phosphorylation of the proline-directed serine/threonine residues. Pin1, a prolyl isomerase, selectively binds to phosphorylated proline-directed serine/threonine residues in target proteins and isomerizes cis isomers to more stable trans configurations. In this study we show that Pin1 associates with phosphorylated neurofilament-H (p-NF-H) in neurons and is colocalized in ALS-affected spinal cord neuronal inclusions. To mimic the pathology of neurodegeneration, we studied glutamate-stressed neurons that displayed increased p-NF-H in perikaryal accumulations that colocalized with Pin1 and led to cell death. Both effects were reduced upon inhibition of Pin1 activity by the use of an inhibitor juglone and down-regulating Pin1 levels through the use of Pin1 small interfering RNA. Thus, isomerization of lys-ser-pro repeat residues that are abundant in NF-H tail domains by Pin1 can regulate NF-H phosphorylation, which suggests that Pin1 inhibition may be an attractive therapeutic target to reduce pathological accumulations of p-NF-H.
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Affiliation(s)
| | - Vyomesh Patel
- Laboratory of Oral and Pharyngeal Cancer, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892
| | | | - Tej K. Pareek
- Department of Pediatrics, Case Western Reserve University, Cleveland, OH 44106
| | | | | | | | - Howard Jaffe
- Protein and Peptide Facility, National Institute of Neurological Disorders and Stroke, and
| | - J. Silvio Gutkind
- Laboratory of Oral and Pharyngeal Cancer, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892
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