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Zheng Z, Qiu Z, Xiong X, Nie A, Zhou W, Qiu H, Zhao H, Wu H, Guo J. Co-activation of NMDAR and mGluRs controls protein nanoparticle-induced osmotic pressure in neurotoxic edema. Biomed Pharmacother 2023; 169:115917. [PMID: 38006617 DOI: 10.1016/j.biopha.2023.115917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2023] [Revised: 11/14/2023] [Accepted: 11/20/2023] [Indexed: 11/27/2023] Open
Abstract
BACKGROUND Glutamate stimuli and hyperactivation of its receptor are predominant determinants of ischemia-induced cytotoxic cerebral edema, which is closely associated with protein nanoparticle (PN)-induced increases in osmotic pressure. Herein, we investigated the electrochemical and mechanical mechanisms underlying the neuron swelling induced by PNs via the co-activation of N-methyl-D-aspartate receptor subunit (NMDAR) and excitatory metabotropic glutamate receptors (mGluRs). RESULTS We observed that co-activation of ionic glutamate receptor NMDAR and Group I metabotropic mGluRs promoted alteration of PN-induced membrane potential and increased intracellular osmosis, which was closely associated with calcium and voltage-dependent ion channels. In addition, activation of NMDAR-induced calmodulin (CaM) and mGluR downstream diacylglycerol (DAG)/protein kinase C α (PKCα) were observed to play crucial roles in cytotoxic hyperosmosis. The crosstalk between CaM and PKCα could upregulate the sensitivity and sustained opening of sulfonylurea receptor 1 (SUR1)-transient receptor potential cation channel subfamily M member 4 (TRPM4) and transmembrane protein 16 A (TMEM16A) channels, respectively, maintaining the massive Na+/Cl- influx, and the resultant neuron hyperosmosis and swelling. Intracellular PNs and Na+/Cl- influx were found to be as potential targets for cerebral edema treatment, using the neurocyte osmosis system and a cerebral ischemic rat model. CONCLUSIONS This study highlights PNs as a key factor in "electrochemistry-tension" signal transduction controlling Na+/Cl- ion channels and increased osmotic pressure in ischemia-induced cytotoxic edema. Moreover, enhanced sensitivity in both Na+ and Cl- ion channels also has a crucial role in cerebral edema.
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Affiliation(s)
- Zihui Zheng
- Department of Biochemistry and Molecular Biology, School of Medicine & Holistic Integrative Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu 210023, China
| | - Zhaoshun Qiu
- Department of Biochemistry and Molecular Biology, School of Medicine & Holistic Integrative Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu 210023, China
| | - Xiyu Xiong
- Department of Biochemistry and Molecular Biology, School of Medicine & Holistic Integrative Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu 210023, China
| | - Aobo Nie
- Department of Biochemistry and Molecular Biology, School of Medicine & Holistic Integrative Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu 210023, China
| | - Wenzhao Zhou
- Department of Biochemistry and Molecular Biology, School of Medicine & Holistic Integrative Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu 210023, China
| | - Huimin Qiu
- Department of Biochemistry and Molecular Biology, School of Medicine & Holistic Integrative Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu 210023, China
| | - Huanhuan Zhao
- Basic Medical Experiment Center, School of Medicine & Holistic Integrative Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu 210023, China
| | - Huiwen Wu
- Laboratory Center for Basic Medical Sciences, Nanjing Medical University, Nanjing 211166, China.
| | - Jun Guo
- Department of Biochemistry and Molecular Biology, School of Medicine & Holistic Integrative Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu 210023, China.
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2
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Jones AC, Kornev AP, Weng JH, Manning G, Taylor SS, Newton AC. Single-residue mutation in protein kinase C toggles between cancer and neurodegeneration. Biochem J 2023; 480:1299-1316. [PMID: 37551632 PMCID: PMC10586763 DOI: 10.1042/bcj20220397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 08/04/2023] [Accepted: 08/07/2023] [Indexed: 08/09/2023]
Abstract
Conventional protein kinase C (cPKC) isozymes tune the signaling output of cells, with loss-of-function somatic mutations associated with cancer and gain-of-function germline mutations identified in neurodegeneration. PKC with impaired autoinhibition is removed from the cell by quality-control mechanisms to prevent the accumulation of aberrantly active enzyme. Here, we examine how a highly conserved residue in the C1A domain of cPKC isozymes permits quality-control degradation when mutated to histidine in cancer (PKCβ-R42H) and blocks down-regulation when mutated to proline in the neurodegenerative disease spinocerebellar ataxia (PKCγ-R41P). Using FRET-based biosensors, we determined that mutation of R42 to any residue, including lysine, resulted in reduced autoinhibition as indicated by higher basal activity and faster agonist-induced plasma membrane translocation. R42 is predicted to form a stabilizing salt bridge with E655 in the C-tail and mutation of E655, but not neighboring E657, also reduced autoinhibition. Western blot analysis revealed that whereas R42H had reduced stability, the R42P mutant was stable and insensitive to activator-induced ubiquitination and down-regulation, an effect previously observed by deletion of the entire C1A domain. Molecular dynamics (MD) simulations and analysis of stable regions of the domain using local spatial pattern (LSP) alignment suggested that P42 interacts with Q66 to impair mobility and conformation of one of the ligand-binding loops. Additional mutation of Q66 to the smaller asparagine (R42P/Q66N), to remove conformational constraints, restored degradation sensitivity. Our results unveil how disease-associated mutations of the same residue in the C1A domain can toggle between gain- or loss-of-function of PKC.
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Affiliation(s)
- Alexander C. Jones
- Department of Pharmacology, University of California, La Jolla, CA 92093, U.S.A
- Biomedical Sciences Graduate Program, University of California, La Jolla, CA 92093, U.S.A
| | - Alexandr P. Kornev
- Department of Pharmacology, University of California, La Jolla, CA 92093, U.S.A
| | - Jui-Hung Weng
- Department of Pharmacology, University of California, La Jolla, CA 92093, U.S.A
| | | | - Susan S. Taylor
- Department of Pharmacology, University of California, La Jolla, CA 92093, U.S.A
| | - Alexandra C. Newton
- Department of Pharmacology, University of California, La Jolla, CA 92093, U.S.A
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3
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Reinhardt R, Leonard TA. A critical evaluation of protein kinase regulation by activation loop autophosphorylation. eLife 2023; 12:e88210. [PMID: 37470698 PMCID: PMC10359097 DOI: 10.7554/elife.88210] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 07/07/2023] [Indexed: 07/21/2023] Open
Abstract
Phosphorylation of proteins is a ubiquitous mechanism of regulating their function, localization, or activity. Protein kinases, enzymes that use ATP to phosphorylate protein substrates are, therefore, powerful signal transducers in eukaryotic cells. The mechanism of phosphoryl-transfer is universally conserved among protein kinases, which necessitates the tight regulation of kinase activity for the orchestration of cellular processes with high spatial and temporal fidelity. In response to a stimulus, many kinases enhance their own activity by autophosphorylating a conserved amino acid in their activation loop, but precisely how this reaction is performed is controversial. Classically, kinases that autophosphorylate their activation loop are thought to perform the reaction in trans, mediated by transient dimerization of their kinase domains. However, motivated by the recently discovered regulation mechanism of activation loop cis-autophosphorylation by a kinase that is autoinhibited in trans, we here review the various mechanisms of autoregulation that have been proposed. We provide a framework for critically evaluating biochemical, kinetic, and structural evidence for protein kinase dimerization and autophosphorylation, and share some thoughts on the implications of these mechanisms within physiological signaling networks.
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Affiliation(s)
- Ronja Reinhardt
- Max Perutz Labs, Vienna Biocenter Campus (VBC)ViennaAustria
- Medical University of Vienna, Center for Medical BiochemistryViennaAustria
| | - Thomas A Leonard
- Max Perutz Labs, Vienna Biocenter Campus (VBC)ViennaAustria
- Medical University of Vienna, Center for Medical BiochemistryViennaAustria
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4
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Jones AC, Kornev AP, Weng JH, Manning G, Taylor SS, Newton AC. Single-residue mutation in protein kinase C toggles between cancer and neurodegeneration. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.16.532226. [PMID: 36993163 PMCID: PMC10055082 DOI: 10.1101/2023.03.16.532226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Conventional protein kinase C (PKC) isozymes tune the signaling output of cells, with loss-of-function somatic mutations associated with cancer and gain-of-function germline mutations identified in neurodegeneration. PKC with impaired autoinhibition is removed from the cell by quality-control mechanisms to prevent accumulation of aberrantly active enzyme. Here, we examine how a single residue in the C1A domain of PKCβ, arginine 42 (R42), permits quality-control degradation when mutated to histidine in cancer (R42H) and blocks downregulation when mutated to proline in the neurodegenerative disease spinocerebellar ataxia (R42P). Using FRET-based biosensors, we determined that mutation of R42 to any residue, including lysine, resulted in reduced autoinhibition as indicated by higher basal activity and faster agonist-induced plasma membrane translocation. R42 is predicted to form a stabilizing salt bridge with E655 in the C-tail and mutation of E655, but not neighboring E657, also reduced autoinhibition. Western blot analysis revealed that whereas R42H had reduced stability, the R42P mutant was stable and insensitive to activator-induced ubiquitination and downregulation, an effect previously observed by deletion of the entire C1A domain. Molecular dynamics (MD) simulations and analysis of stable regions of the domain using local spatial pattern (LSP) alignment suggested that P42 interacts with Q66 to impair mobility and conformation of one of the ligand-binding loops. Additional mutation of Q66 to the smaller asparagine (R42P/Q66N), to remove conformational constraints, restored degradation sensitivity to that of WT. Our results unveil how disease-associated mutations of the same residue in the C1A domain can toggle between gain- or loss-of-function of PKC.
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5
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Foo S, Cazenave-Gassiot A, Wenk MR, Oliferenko S. Diacylglycerol at the inner nuclear membrane fuels nuclear envelope expansion in closed mitosis. J Cell Sci 2023; 136:286881. [PMID: 36695178 DOI: 10.1242/jcs.260568] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 12/22/2022] [Indexed: 01/26/2023] Open
Abstract
Nuclear envelope (NE) expansion must be controlled to maintain nuclear shape and function. The nuclear membrane expands massively during closed mitosis, enabling chromosome segregation within an intact NE. Phosphatidic acid (PA) and diacylglycerol (DG) can both serve as biosynthetic precursors for membrane lipid synthesis. How they are regulated in time and space and what the implications are of changes in their flux for mitotic fidelity are largely unknown. Using genetically encoded PA and DG probes, we show that DG is depleted from the inner nuclear membrane during mitosis in the fission yeast Schizosaccharomyces pombe, but PA does not accumulate, indicating that it is rerouted to membrane synthesis. We demonstrate that DG-to-PA conversion catalyzed by the diacylglycerol kinase Dgk1 (also known as Ptp4) and direct glycerophospholipid synthesis from DG by diacylglycerol cholinephosphotransferase/ethanolaminephosphotransferase Ept1 reinforce NE expansion. We conclude that DG consumption through both the de novo pathway and the Kennedy pathway fuels a spike in glycerophospholipid biosynthesis, controlling NE expansion and, ultimately, mitotic fidelity.
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Affiliation(s)
- Sherman Foo
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK.,Randall Centre for Cell and Molecular Biophysics, School of Basic and Medical Biosciences, King's College London, London SE1 1UL, UK
| | - Amaury Cazenave-Gassiot
- Singapore Lipidomics Incubator, Life Sciences Institute and Precision Medicine Translational Research Program, Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, MD7, 8 Medical Drive, 117596 Singapore
| | - Markus R Wenk
- Singapore Lipidomics Incubator, Life Sciences Institute and Precision Medicine Translational Research Program, Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, MD7, 8 Medical Drive, 117596 Singapore
| | - Snezhana Oliferenko
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK.,Randall Centre for Cell and Molecular Biophysics, School of Basic and Medical Biosciences, King's College London, London SE1 1UL, UK
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6
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Gao C, Gong J, Cao N, Wang Y, Steinberg SF. Lipid-independent activation of a muscle-specific PKCα splicing variant. Am J Physiol Heart Circ Physiol 2022; 323:H825-H832. [PMID: 36112502 PMCID: PMC9550568 DOI: 10.1152/ajpheart.00304.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 08/16/2022] [Accepted: 08/28/2022] [Indexed: 11/22/2022]
Abstract
Protein kinase C-α (PKCα) plays a major role in a diverse range of cellular processes. Studies to date have defined the regulatory controls and function of PKCα entirely based upon the previously annotated ubiquitously expressed prototypical isoform. From RNA-seq-based transcriptome analysis in murine heart, we identified a previously unannotated PKCα variant produced by alternative RNA splicing. This PKCα transcript variant, which we named PKCα-novel exon (PKCα-NE), contains an extra exon between exon 16 and exon 17, and is specifically detected in adult mouse cardiac and skeletal muscle, but not other tissues; it is also detected in human hearts. This transcript variant yields a PKCα isoform with additional 16 amino acids inserted in its COOH-terminal variable region. Although the canonical PKCα enzyme is a lipid-dependent kinase, in vitro kinase assays show that PKCα-NE displays a high level of basal lipid-independent catalytic activity. Our unbiased proteomic analysis identified a specific interaction between PKCα-NE and eukaryotic elongation factor-1α (eEF1A1). Studies in cardiomyocytes link PKCα-NE expression to an increase in eEF1A1 phosphorylation and elevated protein synthesis. In summary, we have identified a previously uncharacterized muscle-specific PKCα splicing variant, PKCα-NE, with distinct biochemical properties that plays a unique role in the control of the protein synthesis machinery in cardiomyocytes.NEW & NOTEWORTHY PKCα is an important signaling molecule extensively studied in many cellular processes. However, no isoforms have been reported for PKCα except one prototypic isoform. Alternative mRNA splicing of Prkca gene was detected for the first time in rodent and human cardiac tissue, which can produce a previously unknown PKCα-novel exon (NE) isoform. The biochemistry and molecular effects of PKCα-NE are markedly different from PKCα wild type, suggesting potential functional diversity of PKCα signaling in muscle.
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Affiliation(s)
- Chen Gao
- Department of Pharmacology and System Physiology, University of Cincinnati, Cincinnati, Ohio
| | - Jianli Gong
- The Department of Pharmacology, Columbia University College of Physicians and Surgeons, New York, New York
| | - Nancy Cao
- University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
| | - Yibin Wang
- Signature Research Program in Cardiovascular and Metabolic Diseases, Duke-NUS Medical School, Singapore
| | - Susan F Steinberg
- The Department of Pharmacology, Columbia University College of Physicians and Surgeons, New York, New York
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7
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Pilo CA, Newton AC. Two Sides of the Same Coin: Protein Kinase C γ in Cancer and Neurodegeneration. Front Cell Dev Biol 2022; 10:929510. [PMID: 35800893 PMCID: PMC9253466 DOI: 10.3389/fcell.2022.929510] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 05/23/2022] [Indexed: 12/23/2022] Open
Abstract
Protein kinase C (PKC) isozymes transduce myriad signals within the cell in response to the generation of second messengers from membrane phospholipids. The conventional isozyme PKCγ reversibly binds Ca2+ and diacylglycerol, which leads to an open, active conformation. PKCγ expression is typically restricted to neurons, but evidence for its expression in certain cancers has emerged. PKC isozymes have been labeled as oncogenes since the discovery that they bind tumor-promoting phorbol esters, however, studies of cancer-associated PKC mutations and clinical trial data showing that PKC inhibitors have worsened patient survival have reframed PKC as a tumor suppressor. Aberrant expression of PKCγ in certain cancers suggests a role outside the brain, although whether PKCγ also acts as a tumor suppressor remains to be established. On the other hand, PKCγ variants associated with spinocerebellar ataxia type 14 (SCA14), a neurodegenerative disorder characterized by Purkinje cell degeneration, enhance basal activity while preventing phorbol ester-mediated degradation. Although the basis for SCA14 Purkinje cell degeneration remains unknown, studies have revealed how altered PKCγ activity rewires cerebellar signaling to drive SCA14. Importantly, enhanced basal activity of SCA14-associated mutants inversely correlates with age of onset, supporting that enhanced PKCγ activity drives SCA14. Thus, PKCγ activity should likely be inhibited in SCA14, whereas restoring PKC activity should be the goal in cancer therapies. This review describes how PKCγ activity can be lost or gained in disease and the overarching need for a PKC structure as a powerful tool to predict the effect of PKCγ mutations in disease.
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Affiliation(s)
- Caila A. Pilo
- Department of Pharmacology, University of California, San Diego, San Diego, CA, United States
- Biomedical Sciences Graduate Program, University of California, San Diego, San Diego, CA, United States
| | - Alexandra C. Newton
- Department of Pharmacology, University of California, San Diego, San Diego, CA, United States
- *Correspondence: Alexandra C. Newton,
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8
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Karadayi R, Mazzocco J, Leclere L, Buteau B, Gregoire S, Belloir C, Koudsi M, Bessard P, Bizeau JB, Dubus E, Fenech C, Briand L, Bretillon L, Bron AM, Fioramonti X, Acar N. Plasmalogens Regulate Retinal Connexin 43 Expression and Müller Glial Cells Gap Junction Intercellular Communication and Migration. Front Cell Dev Biol 2022; 10:864599. [PMID: 35433704 PMCID: PMC9009447 DOI: 10.3389/fcell.2022.864599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 03/16/2022] [Indexed: 11/13/2022] Open
Abstract
Plasmalogens are a specific glycerophospholipid subtype characterized by a vinyl-ether bound at their sn-1 moiety. Their biosynthesis is initiated in the peroxisome by dihydroxyacetone phosphate-acyltransferase (DHAPAT), which is encoded by the DAPAT gene. Previous studies have shown that plasmalogen-deficient mice exhibit major physiological dysfunctions including several eye defects, among which abnormal vascular development of the retina and a reactive activation of macroglial Müller cells. Interestingly, plasmalogen deficiency in mice is also associated with a reduced expression of brain connexin 43 (Cx43). Cx43 is the main connexin subtype of retinal glial cells and is involved in several cellular mechanisms such as calcium-based gap junction intercellular communication (GJIC) or cell migration. Thus, the aim of our work was 1) to confirm the alteration of Cx43 expression in the retina of plasmalogen-deficient DAPAT−/- mice and 2) to investigate whether plasmalogens are involved in crucial functions of Müller cells such as GJIC and cell migration. First, we found that plasmalogen deficiency was associated with a significant reduction of Cx43 expression in the retina of DAPAT−/- mice in vivo. Secondly, using a siRNA targeting DHAPAT in vitro, we found that a 50%-reduction of Müller cells content in plasmalogens was sufficient to significantly downregulate Cx43 expression, while increasing its phosphorylation. Furthermore, plasmalogen-depleted Müller cells exhibited several alterations in ATP-induced GJIC, such as calcium waves of higher amplitude that propagated slower to neighboring cells, including astrocytes. Finally, in vitro plasmalogen depletion was also associated with a significant downregulation of Müller cells migration. Taken together, these data confirm that plasmalogens are critical for the regulation of Cx43 expression and for characteristics of retinal Müller glial cells such as GJIC and cell migration.
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Affiliation(s)
- Rémi Karadayi
- Eye and Nutrition Research Group, CSGA, Université de Bourgogne Franche-Comté, Dijon, France
| | - Julie Mazzocco
- Eye and Nutrition Research Group, CSGA, Université de Bourgogne Franche-Comté, Dijon, France
| | - Laurent Leclere
- Eye and Nutrition Research Group, CSGA, Université de Bourgogne Franche-Comté, Dijon, France
| | - Bénédicte Buteau
- Eye and Nutrition Research Group, CSGA, Université de Bourgogne Franche-Comté, Dijon, France
| | - Stéphane Gregoire
- Eye and Nutrition Research Group, CSGA, Université de Bourgogne Franche-Comté, Dijon, France
| | - Christine Belloir
- Taste and Olfaction Research Group, CSGA, Université de Bourgogne Franche-Comté, Dijon, France
| | - Mounzer Koudsi
- Eye and Nutrition Research Group, CSGA, Université de Bourgogne Franche-Comté, Dijon, France
| | - Pauline Bessard
- Eye and Nutrition Research Group, CSGA, Université de Bourgogne Franche-Comté, Dijon, France
| | - Jean-Baptiste Bizeau
- Eye and Nutrition Research Group, CSGA, Université de Bourgogne Franche-Comté, Dijon, France
| | - Elisabeth Dubus
- Eye and Nutrition Research Group, CSGA, Université de Bourgogne Franche-Comté, Dijon, France
| | - Claire Fenech
- Brain Nutrient Sensing and Energy Homeostasis, CSGA, Université de Bourgogne Franche-Comté, Dijon, France
| | - Loïc Briand
- Taste and Olfaction Research Group, CSGA, Université de Bourgogne Franche-Comté, Dijon, France
| | - Lionel Bretillon
- Eye and Nutrition Research Group, CSGA, Université de Bourgogne Franche-Comté, Dijon, France
| | - Alain M. Bron
- Eye and Nutrition Research Group, CSGA, Université de Bourgogne Franche-Comté, Dijon, France
- Department of Ophthalmology, University Hospital, Dijon, France
| | | | - Niyazi Acar
- Eye and Nutrition Research Group, CSGA, Université de Bourgogne Franche-Comté, Dijon, France
- *Correspondence: Niyazi Acar,
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Mohamed RMSM, Elshazly SM, Mahmoud NM. Amlexanox Exhibits Cardioprotective Effects in 5/6 Nephrectomized Rats. BRAZ J PHARM SCI 2022. [DOI: 10.1590/s2175-97902022e20978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
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10
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Pokorny D, Truebestein L, Fleming KD, Burke JE, Leonard TA. In vitro reconstitution of Sgk3 activation by phosphatidylinositol 3-phosphate. J Biol Chem 2021; 297:100919. [PMID: 34181950 PMCID: PMC8318898 DOI: 10.1016/j.jbc.2021.100919] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 06/09/2021] [Accepted: 06/23/2021] [Indexed: 12/19/2022] Open
Abstract
Serum- and glucocorticoid-regulated kinase 3 (Sgk3) is a serine/threonine protein kinase activated by the phospholipid phosphatidylinositol 3-phosphate (PI3P) downstream of growth factor signaling via class I phosphatidylinositol 3-kinase (PI3K) signaling and by class III PI3K/Vps34-mediated PI3P production on endosomes. Upregulation of Sgk3 activity has recently been linked to a number of human cancers; however, the precise mechanism of activation of Sgk3 is unknown. Here, we use a wide range of cell biological, biochemical, and biophysical techniques, including hydrogen-deuterium exchange mass spectrometry, to investigate the mechanism of activation of Sgk3 by PI3P. We show that Sgk3 is regulated by a combination of phosphorylation and allosteric activation. We demonstrate that binding of Sgk3 to PI3P via its regulatory phox homology (PX) domain induces large conformational changes in Sgk3 associated with its activation and that the PI3P-binding pocket of the PX domain of Sgk3 is sequestered in its inactive conformation. Finally, we reconstitute Sgk3 activation via Vps34-mediated PI3P synthesis on phosphatidylinositol liposomes in vitro. In addition to identifying the mechanism of Sgk3 activation by PI3P, our findings open up potential therapeutic avenues in allosteric inhibitor development to target Sgk3 in cancer.
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Affiliation(s)
- Daniel Pokorny
- Department of Structural and Computational Biology, Max Perutz Labs, Vienna, Austria; Department of Medical Biochemistry, Medical University of Vienna, Vienna, Austria
| | - Linda Truebestein
- Department of Structural and Computational Biology, Max Perutz Labs, Vienna, Austria; Department of Medical Biochemistry, Medical University of Vienna, Vienna, Austria
| | - Kaelin D Fleming
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada
| | - John E Burke
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada; Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Thomas A Leonard
- Department of Structural and Computational Biology, Max Perutz Labs, Vienna, Austria; Department of Medical Biochemistry, Medical University of Vienna, Vienna, Austria.
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11
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Deng F, Zheng X, Sharma I, Dai Y, Wang Y, Kanwar YS. Regulated cell death in cisplatin-induced AKI: relevance of myo-inositol metabolism. Am J Physiol Renal Physiol 2021; 320:F578-F595. [PMID: 33615890 PMCID: PMC8083971 DOI: 10.1152/ajprenal.00016.2021] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 02/08/2021] [Accepted: 02/09/2021] [Indexed: 12/14/2022] Open
Abstract
Regulated cell death (RCD), distinct from accidental cell death, refers to a process of well-controlled programmed cell death with well-defined pathological mechanisms. In the past few decades, various terms for RCDs were coined, and some of them have been implicated in the pathogenesis of various types of acute kidney injury (AKI). Cisplatin is widely used as a chemotherapeutic drug for a broad spectrum of cancers, but its usage was hampered because of being highly nephrotoxic. Cisplatin-induced AKI is commonly seen clinically, and it also serves as a well-established prototypic model for laboratory investigations relevant to acute nephropathy affecting especially the tubular compartment. Literature reports over a period of three decades have indicated that there are multiple types of RCDs, including apoptosis, necroptosis, pyroptosis, ferroptosis, and mitochondrial permeability transition-mediated necrosis, and some of them are pertinent to the pathogenesis of cisplatin-induced AKI. Interestingly, myo-inositol metabolism, a vital biological process that is largely restricted to the kidney, seems to be relevant to the pathogenesis of certain forms of RCDs. A comprehensive understanding of RCDs in cisplatin-induced AKI and their relevance to myo-inositol homeostasis may yield novel therapeutic targets for the amelioration of cisplatin-related nephropathy.
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Affiliation(s)
- Fei Deng
- Department of Urology, The Second Xiangya Hospital, Central South University, Changsha, China
- Department of Pathology, Northwestern University, Chicago, Illinois
- Department of Medicine, Northwestern University, Chicago, Illinois
| | - Xiaoping Zheng
- Department of Pathology, Northwestern University, Chicago, Illinois
- Department of Medicine, Northwestern University, Chicago, Illinois
- Department of Urology, The Third Xiangya Hospital, Central South University, Changsha, China
| | - Isha Sharma
- Department of Pathology, Northwestern University, Chicago, Illinois
- Department of Medicine, Northwestern University, Chicago, Illinois
| | - Yingbo Dai
- Department of Urology, The Third Xiangya Hospital, Central South University, Changsha, China
- Department of Urology, The Fifth Affiliated Hospital of Sun Yet-Sen University, Zhuhai, China
| | - Yinhuai Wang
- Department of Urology, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Yashpal S Kanwar
- Department of Pathology, Northwestern University, Chicago, Illinois
- Department of Medicine, Northwestern University, Chicago, Illinois
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12
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Research progress and the biotechnological applications of multienzyme complex. Appl Microbiol Biotechnol 2021; 105:1759-1777. [PMID: 33564922 DOI: 10.1007/s00253-021-11121-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2020] [Revised: 01/07/2021] [Accepted: 01/16/2021] [Indexed: 11/26/2022]
Abstract
The multienzyme complex system has become a research focus in synthetic biology due to its highly efficient overall catalytic ability and has been applied to various fields. Multienzyme complexes are formed by cascading complexes, which are multiple functionally related enzymes that continuously and efficiently catalyze the production of substrates. Compared with current mainstream microbial cell catalytic systems, in vitro multienzyme molecular machines have many advantages, such as fewer side reactions, a high product yield, a fast reaction speed, easy product separation, a tolerable toxic environment, and robust system operability, showing increasing competitiveness in the field of biomanufacturing. In this review, the research progress of multienzyme complexes in nature and multienzyme cascades in vivo or in vitro will be introduced, and the discovered enzyme cascades concerning scaffolding proteins will also be discussed. This review is expected to provide a more theoretical basis for the modification of multienzyme complexes and broaden their application in the field of synthetic biology. KEY POINTS: • The cascade reactions of some natural multienzyme complexes are reviewed. • The main approaches of constructing artificial multienzyme complexes are summarized. • The structure and application of cellulosomes are discussed and prospected.
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13
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Lippert LG, Ma N, Ritt M, Jain A, Vaidehi N, Sivaramakrishnan S. Kinase inhibitors allosterically disrupt a regulatory interaction to enhance PKCα membrane translocation. J Biol Chem 2021; 296:100339. [PMID: 33508318 PMCID: PMC7949123 DOI: 10.1016/j.jbc.2021.100339] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 01/14/2021] [Accepted: 01/22/2021] [Indexed: 10/28/2022] Open
Abstract
The eukaryotic kinase domain has multiple intrinsically disordered regions whose conformation dictates kinase activity. Small molecule kinase inhibitors (SMKIs) rely on disrupting the active conformations of these disordered regions to inactivate the kinase. While SMKIs are selected for their ability to cause this disruption, the allosteric effects of conformational changes in disordered regions is limited by a lack of dynamic information provided by traditional structural techniques. In this study, we integrated multiscale molecular dynamics simulations with FRET sensors to characterize a novel allosteric mechanism that is selectively triggered by SMKI binding to the protein kinase Cα domain. The indole maleimide inhibitors BimI and sotrastaurin were found to displace the Gly-rich loop (G-loop) that normally shields the ATP-binding site. Displacement of the G-loop interferes with a newly identified, structurally conserved binding pocket for the C1a domain on the N lobe of the kinase domain. This binding pocket, in conjunction with the N-terminal regulatory sequence, masks a diacylglycerol (DAG) binding site on the C1a domain. SMKI-mediated displacement of the G-loop released C1a and exposed the DAG binding site, enhancing protein kinase Cα translocation both to synthetic lipid bilayers and to live cell membranes in the presence of DAG. Inhibitor chemotype determined the extent of the observed allosteric effects on the kinase domain and correlated with the extent of membrane recruitment. Our findings demonstrate the allosteric effects of SMKIs beyond the confines of kinase catalytic conformation and provide an integrated computational-experimental paradigm to investigate parallel mechanisms in other kinases.
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Affiliation(s)
- Lisa G Lippert
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, Minnesota, USA
| | - Ning Ma
- Department of Computational and Quantitative Medicine, Beckman Research Institute of the City of Hope, Duarte, California, USA
| | - Michael Ritt
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, Minnesota, USA
| | - Abhinandan Jain
- The Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| | - Nagarajan Vaidehi
- Department of Computational and Quantitative Medicine, Beckman Research Institute of the City of Hope, Duarte, California, USA.
| | - Sivaraj Sivaramakrishnan
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, Minnesota, USA.
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14
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Tyagi K, Roy A. Evaluating the current status of protein kinase C (PKC)-protein kinase D (PKD) signalling axis as a novel therapeutic target in ovarian cancer. Biochim Biophys Acta Rev Cancer 2020; 1875:188496. [PMID: 33383102 DOI: 10.1016/j.bbcan.2020.188496] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Revised: 12/19/2020] [Accepted: 12/19/2020] [Indexed: 12/14/2022]
Abstract
Ovarian cancer, especially high grade serous ovarian cancer is one of the most lethal gynaecological malignancies with high relapse rate and patient death. Notwithstanding development of several targeted treatment and immunotherapeutic approaches, researchers fail to turn ovarian cancer into a manageable disease. Protein kinase C (PKC) and protein kinase D (PKD) are families of evolutionarily conserved serine/threonine kinases that can be activated by a plethora of extracellular stimuli such as hormones, growth factors and G-protein coupled receptor agonists. Recent literature suggests that a signalling cascade initiated by these two protein kinases regulates a battery of cellular and physiological processes involved in tumorigenesis including cell proliferation, migration, invasion and angiogenesis. In an urgent need to discover novel therapeutic interventions against a deadly pathology like ovarian cancer, we have discussed the status quo of PKC/PKD signalling axis in context of this disease. Additionally, apart from discussing the structural properties and activation mechanisms of PKC/PKD, we have provided a comprehensive review of the recent reports on tumor promoting functions of PKC isoforms and discussed the potential of PKC/PKD signalling axis as a novel target in this lethal pathology. Furthermore, in this review, we have discussed the significance of several recent clinical trials and development of small molecule inhibitors that target PKC/PKD signalling axis in ovarian cancer.
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Affiliation(s)
- Komal Tyagi
- Amity Institute of Molecular Medicine and Stem Cell Research, Amity University, Sector-125, Noida, Uttar Pradesh 201303, India
| | - Adhiraj Roy
- Amity Institute of Molecular Medicine and Stem Cell Research, Amity University, Sector-125, Noida, Uttar Pradesh 201303, India.
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15
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Jones AC, Taylor SS, Newton AC, Kornev AP. Hypothesis: Unifying model of domain architecture for conventional and novel protein kinase C isozymes. IUBMB Life 2020; 72:2584-2590. [PMID: 33166426 DOI: 10.1002/iub.2401] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 10/17/2020] [Accepted: 10/17/2020] [Indexed: 12/26/2022]
Abstract
Protein kinase C (PKC) family members are multi-domain proteins whose function is exquisitely tuned by interdomain interactions that control the spatiotemporal dynamics of their signaling. Despite extensive mechanistic studies on this family of enzymes, no structure of a full-length enzyme that includes all domains has been solved. Here, we take into account the biochemical mechanisms that control autoinhibition, the properties of each individual domain, and previous structural studies to propose a unifying model for the general architecture of PKC family members. This model shows how the C2 domains of conventional and novel PKC isozymes, which have different topologies and different positions in the primary structure, can occupy the same position in the tertiary structure of the kinase. This common architecture of conventional and novel PKC isozymes provides a framework for understanding how disease-associated mutations impair PKC function.
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Affiliation(s)
- Alexander C Jones
- Department of Pharmacology, University of California, San Diego, La Jolla, California, USA.,Biomedical Sciences Graduate Program, University of California, La Jolla, California, USA
| | - Susan S Taylor
- Department of Pharmacology, University of California, San Diego, La Jolla, California, USA
| | - Alexandra C Newton
- Department of Pharmacology, University of California, San Diego, La Jolla, California, USA
| | - Alexandr P Kornev
- Department of Pharmacology, University of California, San Diego, La Jolla, California, USA
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16
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Li N, Zeng Y, Huang J. Signaling pathways and clinical application of RASSF1A and SHOX2 in lung cancer. J Cancer Res Clin Oncol 2020; 146:1379-1393. [PMID: 32266538 DOI: 10.1007/s00432-020-03188-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 03/17/2020] [Indexed: 12/16/2022]
Abstract
BACKGROUND An increasing number of studies have focused on the early diagnostic value of the methylation of RASSF1A and SHOX2 in lung cancer. However, the intricate cellular events related to RASSF1A and SHOX2 in lung cancer are still a mystery. For researchers and clinicians aiming to more profoundly understand the diagnostic value of methylated RASSF1A and SHOX2 in lung cancer, this review will provide deeper insights into the molecular events of RASSF1A and SHOX2 in lung cancer. METHODOLOGY We searched for relevant publications in the PubMed and Google Scholar databases using the keywords "RASSF1A", "SHOX2" and "lung cancer" etc. First, we reviewed the RASSF1A and SHOX2 genes, from their family structures to the functions of their basic structural domains. Then we mainly focused on the roles of RASSF1A and SHOX2 in lung cancer, especially on their molecular events in recent decades. Finally, we compared the value of measuring RASSF1A and SHOX2 gene methylation with that of the common methods for the diagnosis of lung cancer patients. RESULTS The RASSF1A and SHOX2 genes were confirmed to be regulators or effectors of multiple cancer signaling pathways, driving tumorigenesis and lung cancer progression. The detection of RASSF1A and SHOX2 gene methylation has higher sensitivity and specificity than other commonly used methods for diagnosing lung cancer, especially in the early stage. CONCLUSIONS The RASSF1A and SHOX2 genes are critical for the processes of tumorigenesis, development, metastasis, drug resistance, and recurrence in lung cancer. The combined detection of RASSF1A and SHOX2 gene methylation was identified as an excellent method for the screening and surveillance of lung cancer that exhibits high sensitivity and specificity.
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Affiliation(s)
- Nanhong Li
- Department of Pathology, Guangdong Medical University, Zhanjiang, 524023, China
| | - Yu Zeng
- Department of Respiration, The Second Affiliated Hospital of Guangdong Medical University, Zhanjiang, 524003, China
| | - Jian Huang
- Department of Pathology, Guangdong Medical University, Zhanjiang, 524023, China.
- Pathological Diagnosis and Research Center, Affiliated Hospital, Guangdong Medical University, Zhanjiang, 524001, China.
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17
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Reinhardt R, Truebestein L, Schmidt HA, Leonard TA. It Takes Two to Tango: Activation of Protein Kinase D by Dimerization. Bioessays 2020; 42:e1900222. [PMID: 31997382 DOI: 10.1002/bies.201900222] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 01/10/2020] [Indexed: 12/23/2022]
Abstract
The recent discovery and structure determination of a novel ubiquitin-like dimerization domain in protein kinase D (PKD) has significant implications for its activation. PKD is a serine/threonine kinase activated by the lipid second messenger diacylglycerol (DAG). It is an essential and highly conserved protein that is implicated in plasma membrane directed trafficking processes from the trans-Golgi network. However, many open questions surround its mechanism of activation, its localization, and its role in the biogenesis of cargo transport carriers. In reviewing this field, the focus is primarily on the mechanisms that control the activation of PKD at precise locations in the cell. In light of the new structural findings, the understanding of the mechanisms underlying PKD activation is critically evaluated, with particular emphasis on the role of dimerization in PKD autophosphorylation, and the provenance and recognition of the DAG that activates PKD.
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Affiliation(s)
- Ronja Reinhardt
- Department of Structural and Computational Biology, Max Perutz Labs, Vienna Biocenter, 1030, Vienna, Austria.,Department of Medical Biochemistry, Medical University of Vienna, 1030, Vienna, Austria
| | - Linda Truebestein
- Department of Structural and Computational Biology, Max Perutz Labs, Vienna Biocenter, 1030, Vienna, Austria.,Department of Medical Biochemistry, Medical University of Vienna, 1030, Vienna, Austria
| | - Heiko A Schmidt
- Center for Integrative Bioinformatics Vienna, Max Perutz Labs, University of Vienna and Medical University of Vienna, Vienna Biocenter, 1030, Vienna, Austria
| | - Thomas A Leonard
- Department of Structural and Computational Biology, Max Perutz Labs, Vienna Biocenter, 1030, Vienna, Austria.,Department of Medical Biochemistry, Medical University of Vienna, 1030, Vienna, Austria
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18
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Elsner DJ, Siess KM, Gossenreiter T, Hartl M, Leonard TA. A ubiquitin-like domain controls protein kinase D dimerization and activation by trans-autophosphorylation. J Biol Chem 2019; 294:14422-14441. [PMID: 31406020 PMCID: PMC6768651 DOI: 10.1074/jbc.ra119.008713] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 07/30/2019] [Indexed: 11/25/2022] Open
Abstract
Protein kinase D (PKD) is an essential Ser/Thr kinase in animals and controls a variety of diverse cellular functions, including vesicle trafficking and mitogenesis. PKD is activated by recruitment to membranes containing the lipid second messenger diacylglycerol (DAG) and subsequent phosphorylation of its activation loop. Here, we report the crystal structure of the PKD N terminus at 2.2 Å resolution containing a previously unannotated ubiquitin-like domain (ULD), which serves as a dimerization domain. A single point mutation in the dimerization interface of the ULD not only abrogated dimerization in cells but also prevented PKD activation loop phosphorylation upon DAG production. We further show that the kinase domain of PKD dimerizes in a concentration-dependent manner and autophosphorylates on a single residue in its activation loop. We also provide evidence that PKD is expressed at concentrations 2 orders of magnitude below the ULD dissociation constant in mammalian cells. We therefore propose a new model for PKD activation in which the production of DAG leads to the local accumulation of PKD at the membrane, which drives ULD-mediated dimerization and subsequent trans-autophosphorylation of the kinase domain.
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Affiliation(s)
- Daniel J Elsner
- Department of Structural and Computational Biology, Max Perutz Labs, Campus Vienna Biocenter 5, 1030 Vienna, Austria.,Department of Medical Biochemistry, Medical University of Vienna, 1090 Vienna, Austria
| | - Katharina M Siess
- Department of Structural and Computational Biology, Max Perutz Labs, Campus Vienna Biocenter 5, 1030 Vienna, Austria.,Department of Medical Biochemistry, Medical University of Vienna, 1090 Vienna, Austria
| | - Thomas Gossenreiter
- Mass Spectrometry Facility, Max Perutz Labs, Dr. Bohr-Gasse 3, 1030 Vienna, Austria
| | - Markus Hartl
- Mass Spectrometry Facility, Max Perutz Labs, Dr. Bohr-Gasse 3, 1030 Vienna, Austria.,Department of Biochemistry and Cell Biology, Max Perutz Labs, University of Vienna, Vienna Biocenter, Dr. Bohr-Gasse 9, 1030 Vienna, Austria
| | - Thomas A Leonard
- Department of Structural and Computational Biology, Max Perutz Labs, Campus Vienna Biocenter 5, 1030 Vienna, Austria .,Department of Medical Biochemistry, Medical University of Vienna, 1090 Vienna, Austria
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19
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The Inner Nuclear Membrane Is a Metabolically Active Territory that Generates Nuclear Lipid Droplets. Cell 2018; 174:700-715.e18. [PMID: 29937227 PMCID: PMC6371920 DOI: 10.1016/j.cell.2018.05.047] [Citation(s) in RCA: 166] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Revised: 03/01/2018] [Accepted: 05/22/2018] [Indexed: 11/24/2022]
Abstract
The inner nuclear membrane (INM) encases the genome and is fused with the outer nuclear membrane (ONM) to form the nuclear envelope. The ONM is contiguous with the endoplasmic reticulum (ER), the main site of phospholipid synthesis. In contrast to the ER and ONM, evidence for a metabolic activity of the INM has been lacking. Here, we show that the INM is an adaptable membrane territory capable of lipid metabolism. S. cerevisiae cells target enzymes to the INM that can promote lipid storage. Lipid storage involves the synthesis of nuclear lipid droplets from the INM and is characterized by lipid exchange through Seipin-dependent membrane bridges. We identify the genetic circuit for nuclear lipid droplet synthesis and a role of these organelles in regulating this circuit by sequestration of a transcription factor. Our findings suggest a link between INM metabolism and genome regulation and have potential relevance for human lipodystrophy. INM is metabolically active and stores lipids via nuclear lipid droplets (nLDs) Intranuclear lipid sensors detect DAG enrichment at INM and PA/DAG on nLDs Nutrients and Opi1 transcriptional circuit regulate nLD synthesis Lipodystrophy-related Seipin promotes formation of INM-nLD membrane bridges
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20
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Yang H, Staveness D, Ryckbosch SM, Axtman AD, Loy BA, Barnes AB, Pande VS, Schaefer J, Wender PA, Cegelski L. REDOR NMR Reveals Multiple Conformers for a Protein Kinase C Ligand in a Membrane Environment. ACS CENTRAL SCIENCE 2018; 4:89-96. [PMID: 29392180 PMCID: PMC5785774 DOI: 10.1021/acscentsci.7b00475] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Indexed: 05/05/2023]
Abstract
Bryostatin 1 (henceforth bryostatin) is in clinical trials for the treatment of Alzheimer's disease and for HIV/AIDS eradication. It is also a preclinical lead for cancer immunotherapy and other therapeutic indications. Yet nothing is known about the conformation of bryostatin bound to its protein kinase C (PKC) target in a membrane microenvironment. As a result, efforts to design more efficacious, better tolerated, or more synthetically accessible ligands have been limited to structures that do not include PKC or membrane effects known to influence PKC-ligand binding. This problem extends more generally to many membrane-associated proteins in the human proteome. Here, we use rotational-echo double-resonance (REDOR) solid-state NMR to determine the conformations of PKC modulators bound to the PKCδ-C1b domain in the presence of phospholipid vesicles. The conformationally limited PKC modulator phorbol diacetate (PDAc) is used as an initial test substrate. While unanticipated partitioning of PDAc between an immobilized protein-bound state and a mobile state in the phospholipid assembly was observed, a single conformation in the bound state was identified. In striking contrast, a bryostatin analogue (bryolog) was found to exist exclusively in a protein-bound state, but adopts a distribution of conformations as defined by three independent distance measurements. The detection of multiple PKCδ-C1b-bound bryolog conformers in a functionally relevant phospholipid complex reveals the inherent dynamic nature of cellular systems that is not captured with single-conformation static structures. These results indicate that binding, selectivity, and function of PKC modulators, as well as the design of new modulators, are best addressed using a dynamic multistate model, an analysis potentially applicable to other membrane-associated proteins.
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Affiliation(s)
- Hao Yang
- Department
of Chemistry, Washington University in St.
Louis, St. Louis, Missouri 63130, United
States
| | - Daryl Staveness
- Department
of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Steven M. Ryckbosch
- Department
of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Alison D. Axtman
- Department
of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Brian A. Loy
- Department
of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Alexander B. Barnes
- Department
of Chemistry, Washington University in St.
Louis, St. Louis, Missouri 63130, United
States
| | - Vijay S. Pande
- Department
of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Jacob Schaefer
- Department
of Chemistry, Washington University in St.
Louis, St. Louis, Missouri 63130, United
States
| | - Paul A. Wender
- Department
of Chemistry, Stanford University, Stanford, California 94305, United States
- Department
of Chemical and Systems Biology, Stanford
University, Stanford, California 94305, United States
| | - Lynette Cegelski
- Department
of Chemistry, Stanford University, Stanford, California 94305, United States
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21
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Trexler AJ, Taraska JW. Regulation of insulin exocytosis by calcium-dependent protein kinase C in beta cells. Cell Calcium 2017; 67:1-10. [PMID: 29029784 DOI: 10.1016/j.ceca.2017.07.008] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 07/25/2017] [Accepted: 07/27/2017] [Indexed: 12/27/2022]
Abstract
The control of insulin release from pancreatic beta cells helps ensure proper blood glucose level, which is critical for human health. Protein kinase C has been shown to be one key control mechanism for this process. After glucose stimulation, calcium influx into beta cells triggers exocytosis of insulin-containing dense-core granules and activates protein kinase C via calcium-dependent phospholipase C-mediated generation of diacylglycerol. Activated protein kinase C potentiates insulin release by enhancing the calcium sensitivity of exocytosis, likely by affecting two main pathways that could be linked: (1) the reorganization of the cortical actin network, and (2) the direct phosphorylation of critical exocytotic proteins such as munc18, SNAP25, and synaptotagmin. Here, we review what is currently known about the molecular mechanisms of protein kinase C action on each of these pathways and how these effects relate to the control of insulin release by exocytosis. We identify remaining challenges in the field and suggest how these challenges might be addressed to advance our understanding of the regulation of insulin release in health and disease.
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Affiliation(s)
- Adam J Trexler
- National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, United States
| | - Justin W Taraska
- National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, United States.
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22
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Różycki B, Cieplak M. Stiffness of the C-terminal disordered linker affects the geometry of the active site in endoglucanase Cel8A. MOLECULAR BIOSYSTEMS 2017; 12:3589-3599. [PMID: 27714009 DOI: 10.1039/c6mb00606j] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Cellulosomes are complex multi-enzyme machineries which efficiently degrade plant cell-wall polysaccharides. The multiple domains of the cellulosome proteins are often tethered together by intrinsically disordered regions. The properties and functions of these disordered linkers are not well understood. In this work, we study endoglucanase Cel8A, which is a relevant enzymatic component of the cellulosomes of Clostridium thermocellum. We use both all-atom and coarse-grained simulations to investigate how the conformations of the catalytic domain of Cel8A are affected by the disordered linker at its C terminus. We find that when the endoglucanase is bound to its substrate, the effective stiffness of the linker can influence the distances between groups of amino-acid residues throughout the entire enzymatic domain. In particular, variations in the linker stiffness can lead to small changes in the geometry of the active-site cleft. We suggest that such geometrical changes may have an effect on the catalytic activity of the enzyme.
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Affiliation(s)
- Bartosz Różycki
- Institute of Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warsaw, Poland.
| | - Marek Cieplak
- Institute of Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warsaw, Poland.
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23
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Morales KA, Yang Y, Cole TR, Igumenova TI. Dynamic Response of the C2 Domain of Protein Kinase Cα to Ca 2+ Binding. Biophys J 2017; 111:1655-1667. [PMID: 27760353 DOI: 10.1016/j.bpj.2016.09.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 09/04/2016] [Accepted: 09/07/2016] [Indexed: 11/28/2022] Open
Abstract
Ca2+-dependent conserved-region 2 (C2) domains target their host signaling proteins to anionic membranes. The Ca2+-binding event is a prerequisite for membrane association. Here, we investigate multiscale metal-ion-dependent dynamics of the C2 domain of protein kinase Cα (C2α) using NMR spectroscopy. Interactions with metal ions attenuate microsecond-timescale motions of the loop regions, indicating that preorganization of the metal-binding loops occurs before membrane insertion. Binding of a full complement of Ca2+ ions has a profound effect on the millisecond-timescale dynamics of the N- and C-terminal regions of C2α. We propose that Ca2+ binding allosterically destabilizes the terminal regions of C2α and thereby facilitates the conformational rearrangement necessary for full membrane insertion and activation of protein kinase Cα.
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Affiliation(s)
- Krystal A Morales
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas
| | - Yuan Yang
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas
| | - Taylor R Cole
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas
| | - Tatyana I Igumenova
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas.
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24
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Leroux AE, Schulze JO, Biondi RM. AGC kinases, mechanisms of regulation and innovative drug development. Semin Cancer Biol 2017; 48:1-17. [PMID: 28591657 DOI: 10.1016/j.semcancer.2017.05.011] [Citation(s) in RCA: 92] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 05/16/2017] [Accepted: 05/31/2017] [Indexed: 12/22/2022]
Abstract
The group of AGC kinases consists of 63 evolutionarily related serine/threonine protein kinases comprising PDK1, PKB/Akt, SGK, PKC, PRK/PKN, MSK, RSK, S6K, PKA, PKG, DMPK, MRCK, ROCK, NDR, LATS, CRIK, MAST, GRK, Sgk494, and YANK, while two other families, Aurora and PLK, are the most closely related to the group. Eight of these families are physiologically activated downstream of growth factor signalling, while other AGC kinases are downstream effectors of a wide range of signals. The different AGC kinase families share aspects of their mechanisms of inhibition and activation. In the present review, we update the knowledge of the mechanisms of regulation of different AGC kinases. The conformation of the catalytic domain of many AGC kinases is regulated allosterically through the modulation of the conformation of a regulatory site on the small lobe of the kinase domain, the PIF-pocket. The PIF-pocket acts like an ON-OFF switch in AGC kinases with different modes of regulation, i.e. PDK1, PKB/Akt, LATS and Aurora kinases. In this review, we make emphasis on how the knowledge of the molecular mechanisms of regulation can guide the discovery and development of small allosteric modulators. Molecular probes stabilizing the PIF-pocket in the active conformation are activators, while compounds stabilizing the disrupted site are allosteric inhibitors. One challenge for the rational development of allosteric modulators is the lack of complete structural information of the inhibited forms of full-length AGC kinases. On the other hand, we suggest that the available information derived from molecular biology and biochemical studies can already guide screening strategies for the identification of innovative mode of action molecular probes and the development of selective allosteric drugs for the treatment of human diseases.
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Affiliation(s)
- Alejandro E Leroux
- Instituto de Investigación en Biomedicina de Buenos Aires (IBioBA) - CONICET - Partner Institute of the Max Planck Society, Buenos Aires C1425FQD, Argentina.
| | - Jörg O Schulze
- Research Group PhosphoSites, Medizinische Klinik 1, Universitätsklinikum Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt am Main, Germany.
| | - Ricardo M Biondi
- Instituto de Investigación en Biomedicina de Buenos Aires (IBioBA) - CONICET - Partner Institute of the Max Planck Society, Buenos Aires C1425FQD, Argentina; Research Group PhosphoSites, Medizinische Klinik 1, Universitätsklinikum Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt am Main, Germany; German Cancer Consortium (DKTK), Heidelberg, Germany, German Cancer Research Center (DKFZ), Heidelberg, Germany.
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25
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Sommese RF, Ritt M, Swanson CJ, Sivaramakrishnan S. The Role of Regulatory Domains in Maintaining Autoinhibition in the Multidomain Kinase PKCα. J Biol Chem 2017; 292:2873-2880. [PMID: 28049730 DOI: 10.1074/jbc.m116.768457] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Revised: 12/30/2016] [Indexed: 11/06/2022] Open
Abstract
Resolving the conformational dynamics of large multidomain proteins has proven to be a significant challenge. Here we use a variety of techniques to dissect the roles of individual protein kinase Cα (PKCα) regulatory domains in maintaining catalytic autoinhibition. We find that whereas the pseudosubstrate domain is necessary for autoinhibition it is not sufficient. Instead, each regulatory domain (C1a, C1b, and C2) appears to strengthen the pseudosubstrate-catalytic domain interaction in a nucleotide-dependent manner. The pseudosubstrate and C1a domains, however, are minimally essential for maintaining the inactivated state. Furthermore, disrupting known interactions between the C1a and other regulatory domains releases the autoinhibited interaction and increases basal activity. Modulating this interaction between the catalytic and regulatory domains reveals a direct correlation between autoinhibition and membrane translocation following PKC activation.
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Affiliation(s)
- Ruth F Sommese
- From the Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, Minnesota 55455 and
| | - Michael Ritt
- From the Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, Minnesota 55455 and
| | - Carter J Swanson
- the Biophysics Program, University of Michigan, Ann Arbor, Michigan 48109
| | - Sivaraj Sivaramakrishnan
- From the Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, Minnesota 55455 and
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Czikora A, Lundberg DJ, Abramovitz A, Lewin NE, Kedei N, Peach ML, Zhou X, Merritt RC, Craft EA, Braun DC, Blumberg PM. Structural Basis for the Failure of the C1 Domain of Ras Guanine Nucleotide Releasing Protein 2 (RasGRP2) to Bind Phorbol Ester with High Affinity. J Biol Chem 2016; 291:11133-47. [PMID: 27022025 PMCID: PMC4900263 DOI: 10.1074/jbc.m116.725333] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 03/28/2016] [Indexed: 11/06/2022] Open
Abstract
The C1 domain represents the recognition module for diacylglycerol and phorbol esters in protein kinase C, Ras guanine nucleotide releasing protein (RasGRP), and related proteins. RasGRP2 is exceptional in that its C1 domain has very weak binding affinity (Kd = 2890 ± 240 nm for [(3)H]phorbol 12,13-dibutyrate. We have identified four amino acid residues responsible for this lack of sensitivity. Replacing Asn(7), Ser(8), Ala(19), and Ile(21) with the corresponding residues from RasGRP1/3 (Thr(7), Tyr(8), Gly(19), and Leu(21), respectively) conferred potent binding affinity (Kd = 1.47 ± 0.03 nm) in vitro and membrane translocation in response to phorbol 12-myristate 13-acetate in LNCaP cells. Mutant C1 domains incorporating one to three of the four residues showed intermediate behavior with S8Y making the greatest contribution. Binding activity for diacylglycerol was restored in parallel. The requirement for anionic phospholipid for [(3)H]phorbol 12,13-dibutyrate binding was determined; it decreased in going from the single S8Y mutant to the quadruple mutant. The full-length RasGRP2 protein with the mutated C1 domains also showed strong phorbol ester binding, albeit modestly weaker than that of the C1 domain alone (Kd = 8.2 ± 1.1 nm for the full-length protein containing all four mutations), and displayed translocation in response to phorbol ester. RasGRP2 is a guanyl exchange factor for Rap1. Consistent with the ability of phorbol ester to induce translocation of the full-length RasGRP2 with the mutated C1 domain, phorbol ester enhanced the ability of the mutated RasGRP2 to activate Rap1. Modeling confirmed that the four mutations helped the binding cleft maintain a stable conformation.
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Affiliation(s)
- Agnes Czikora
- From the Laboratory of Cancer Biology and Genetics, Center for Cancer Research, NCI, National Institutes of Health, Bethesda, Maryland 20892
| | - Daniel J Lundberg
- Department of Science, Technology, and Mathematics, Gallaudet University, Washington, D. C. 20002, and
| | - Adelle Abramovitz
- From the Laboratory of Cancer Biology and Genetics, Center for Cancer Research, NCI, National Institutes of Health, Bethesda, Maryland 20892
| | - Nancy E Lewin
- From the Laboratory of Cancer Biology and Genetics, Center for Cancer Research, NCI, National Institutes of Health, Bethesda, Maryland 20892
| | - Noemi Kedei
- From the Laboratory of Cancer Biology and Genetics, Center for Cancer Research, NCI, National Institutes of Health, Bethesda, Maryland 20892
| | - Megan L Peach
- Basic Science Program, Leidos Biomedical Research, Inc., Chemical Biology Laboratory, Frederick National Laboratory for Cancer Research, Frederick, Maryland 21702
| | - Xiaoling Zhou
- From the Laboratory of Cancer Biology and Genetics, Center for Cancer Research, NCI, National Institutes of Health, Bethesda, Maryland 20892
| | - Raymond C Merritt
- Department of Science, Technology, and Mathematics, Gallaudet University, Washington, D. C. 20002, and
| | - Elizabeth A Craft
- Department of Science, Technology, and Mathematics, Gallaudet University, Washington, D. C. 20002, and
| | - Derek C Braun
- Department of Science, Technology, and Mathematics, Gallaudet University, Washington, D. C. 20002, and
| | - Peter M Blumberg
- From the Laboratory of Cancer Biology and Genetics, Center for Cancer Research, NCI, National Institutes of Health, Bethesda, Maryland 20892,
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