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Bock F, Elias BC, Dong X, Parekh DV, Mernaugh G, Viquez OM, Hassan A, Amara VR, Liu J, Brown KL, Terker AS, Chiusa M, Gewin LS, Fogo AB, Brakebusch CH, Pozzi A, Zent R. Rac1 promotes kidney collecting duct integrity by limiting actomyosin activity. J Cell Biol 2021; 220:212704. [PMID: 34647970 PMCID: PMC8563289 DOI: 10.1083/jcb.202103080] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 07/27/2021] [Accepted: 09/08/2021] [Indexed: 12/31/2022] Open
Abstract
A polarized collecting duct (CD), formed from the branching ureteric bud (UB), is a prerequisite for an intact kidney. The small Rho GTPase Rac1 is critical for actin cytoskeletal regulation. We investigated the role of Rac1 in the kidney collecting system by selectively deleting it in mice at the initiation of UB development. The mice exhibited only a mild developmental phenotype; however, with aging, the CD developed a disruption of epithelial integrity and function. Despite intact integrin signaling, Rac1-null CD cells had profound adhesion and polarity abnormalities that were independent of the major downstream Rac1 effector, Pak1. These cells did however have a defect in the WAVE2–Arp2/3 actin nucleation and polymerization apparatus, resulting in actomyosin hyperactivity. The epithelial defects were reversible with direct myosin II inhibition. Furthermore, Rac1 controlled lateral membrane height and overall epithelial morphology by maintaining lateral F-actin and restricting actomyosin. Thus, Rac1 promotes CD epithelial integrity and morphology by restricting actomyosin via Arp2/3-dependent cytoskeletal branching.
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Affiliation(s)
- Fabian Bock
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
| | - Bertha C Elias
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
| | - Xinyu Dong
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
| | - Diptiben V Parekh
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN.,Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA
| | - Glenda Mernaugh
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
| | - Olga M Viquez
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
| | - Anjana Hassan
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
| | - Venkateswara Rao Amara
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
| | - Jiageng Liu
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
| | - Kyle L Brown
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
| | - Andrew S Terker
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
| | - Manuel Chiusa
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN.,Department of Veterans Affairs Hospital, Nashville, TN
| | - Leslie S Gewin
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN.,Department of Veterans Affairs Hospital, Nashville, TN.,Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN
| | - Agnes B Fogo
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN
| | - Cord H Brakebusch
- Biotech Research Center, University of Copenhagen, Copenhagen, Denmark
| | - Ambra Pozzi
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN.,Department of Veterans Affairs Hospital, Nashville, TN.,Department of Molecular Physiology & Biophysics, Vanderbilt University School of Medicine, Nashville, TN
| | - Roy Zent
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN.,Department of Veterans Affairs Hospital, Nashville, TN.,Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN
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Ai X, Yan J, Pogwizd SM. Serine-threonine protein phosphatase regulation of Cx43 dephosphorylation in arrhythmogenic disorders. Cell Signal 2021; 86:110070. [PMID: 34217833 PMCID: PMC8963383 DOI: 10.1016/j.cellsig.2021.110070] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 06/11/2021] [Accepted: 06/29/2021] [Indexed: 12/11/2022]
Abstract
Regulation of cell-to-cell communication in the heart by the gap junction protein Connexin43 (Cx43) involves modulation of Cx43 phosphorylation state by protein kinases, and dephosphorylation by protein phosphatases. Dephosphorylation of Cx43 has been associated with impaired intercellular coupling and enhanced arrhythmogenesis in various pathologic states. While there has been extensive study of the protein kinases acting on Cx43, there has been limited studies of the protein phosphatases that may underlie Cx43 dephosphorylation. The focus of this review is to introduce serine-threonine protein phosphatase regulation of Cx43 phosphorylation state and cell-to-cell communication, and its impact on arrhythmogenesis in the setting of chronic heart failure and myocardial ischemia, as well as on atrial fibrillation. We also discuss the therapeutic potential of modulating protein phosphatases to treat arrhythmias in these clinical settings.
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Affiliation(s)
- Xun Ai
- Department of Physiology & Biophysics, Rush University, Chicago, IL, United States of America
| | - Jiajie Yan
- Department of Physiology & Biophysics, Rush University, Chicago, IL, United States of America
| | - Steven M Pogwizd
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States of America.
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Märker R, Blank-Landeshammer B, Beier-Rosberger A, Sickmann A, Kück U. Phosphoproteomic analysis of STRIPAK mutants identifies a conserved serine phosphorylation site in PAK kinase CLA4 to be important in fungal sexual development and polarized growth. Mol Microbiol 2020; 113:1053-1069. [PMID: 32022307 DOI: 10.1111/mmi.14475] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Revised: 01/16/2020] [Accepted: 01/20/2020] [Indexed: 02/06/2023]
Abstract
The highly conserved striatin-interacting phosphatases and kinases (STRIPAK) complex regulates phosphorylation/dephosphorylation of developmental proteins in eukaryotic microorganisms, animals and humans. To first identify potential targets of STRIPAK, we performed extensive isobaric tags for relative and absolute quantification-based proteomic and phosphoproteomic analyses in the filamentous fungus Sordaria macrospora. In total, we identified 4,193 proteins and 2,489 phosphoproteins, which are represented by 10,635 phosphopeptides. By comparing phosphorylation data from wild type and mutants, we identified 228 phosphoproteins to be regulated in all three STRIPAK mutants, thus representing potential targets of STRIPAK. To provide an exemplarily functional analysis of a STRIPAK-dependent phosphorylated protein, we selected CLA4, a member of the conserved p21-activated kinase family. Functional characterization of the ∆cla4 deletion strain showed that CLA4 controls sexual development and polarized growth. To determine the functional relevance of CLA4 phosphorylation and the impact of specific phosphorylation sites on development, we next generated phosphomimetic and -deficient variants of CLA4. This analysis identified (de)phosphorylation of a highly conserved serine (S685) residue in the catalytic domain of CLA4 as being important for fungal cellular development. Collectively, these analyses significantly contribute to the understanding of the mechanistic function of STRIPAK as a phosphatase and kinase signaling complex.
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Affiliation(s)
- Ramona Märker
- Lehrstuhl für Allgemeine und Molekulare Botanik, Ruhr-Universität, Bochum, Germany
| | | | - Anna Beier-Rosberger
- Lehrstuhl für Allgemeine und Molekulare Botanik, Ruhr-Universität, Bochum, Germany
| | - Albert Sickmann
- Leibniz-Institut für Analytische Wissenschaften-ISAS-e.V., Dortmund, Germany
| | - Ulrich Kück
- Lehrstuhl für Allgemeine und Molekulare Botanik, Ruhr-Universität, Bochum, Germany
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4
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Singh V, Davidson A, Hume PJ, Koronakis V. Pathogenic Escherichia coli Hijacks GTPase-Activated p21-Activated Kinase for Actin Pedestal Formation. mBio 2019; 10:e01876-19. [PMID: 31431554 PMCID: PMC6703428 DOI: 10.1128/mbio.01876-19] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Accepted: 07/24/2019] [Indexed: 12/26/2022] Open
Abstract
Enteropathogenic Escherichia coli and enterohemorrhagic E. coli (EPEC and EHEC, respectively) are extracellular pathogens that reorganize the host cell cytoskeleton to form "actin pedestals" beneath the tightly adherent bacteria, a critical step in pathogenesis. EPEC and EHEC inject effector proteins that manipulate host cell signaling cascades to trigger pedestal assembly. One such effector, EspG, has been reported to bind and activate p21-activated kinase (PAK), a key cytoskeletal regulator, but the function of this interaction and whether it impacts pedestal assembly are unknown. Here, we demonstrate that deletion of espG significantly impairs pedestal formation and attachment by both EPEC and EHEC. This role of EspG is shown to be dependent on its interaction with PAK. Unexpectedly, EspG was able to subvert PAK only in the presence of Rho family small GTPases, which function to both concentrate PAK at the membrane and stimulate PAK activation. Our findings reveal a novel mechanism by which EspG hijacks PAK and sustains its active state to drive bacterial attachment to host cells.IMPORTANCE Enteropathogenic E. coli and enterohemorrhagic E. coli (EPEC and EHEC, respectively) remain a significant global health problem. Both EPEC and EHEC initiate infection by attaching to cells in the host intestine, triggering the formation of actin-rich "pedestal" structures directly beneath the adherent pathogen. These bacteria inject their own receptor into host cells, which upon binding to a protein on the pathogen surface triggers pedestal formation. Multiple other proteins are also delivered into the cells of the host intestine, but how they contribute to disease is often less clear. Here, we show how one of these injected proteins, EspG, hijacks a host signaling pathway for pedestal production. This provides new insights into this essential early stage in EPEC and EHEC disease.
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Affiliation(s)
- Vikash Singh
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Anthony Davidson
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Peter J Hume
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Vassilis Koronakis
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
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Chen W, Ghobrial RM, Li XC, Kloc M. Inhibition of RhoA and mTORC2/Rictor by Fingolimod (FTY720) induces p21-activated kinase 1, PAK-1 and amplifies podosomes in mouse peritoneal macrophages. Immunobiology 2018; 223:634-647. [PMID: 30005970 DOI: 10.1016/j.imbio.2018.07.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 06/25/2018] [Accepted: 07/05/2018] [Indexed: 02/08/2023]
Abstract
Macrophage functions in the immune response depend on their ability to infiltrate tissues and organs. The penetration between and within the tissues requires degradation of extracellular matrix (ECM), a function performed by the specialized, endopeptidase- and actin filament- rich organelles located at the ventral surface of macrophage, called the podosomes. Podosome formation requires local inhibition of small GTPase RhoA activity, and depends on Rac 1/Rho guanine nucleotide exchange factor 7, β-PIX and its binding partner the p21-activated kinase (PAK-1). The activity of RhoA and Rac 1 is in turn regulated by mTOR/mTORC2 pathway. Here we showed that a fungus metabolite Fingolimod (FTY720, Gilenya), which is clinically approved for the treatment of multiple sclerosis, down-regulates Rictor, which is a signature molecule of mTORC2 and dictates its substrate (actin cytoskeleton) specificity, down-regulates RhoA, up-regulates PAK-1, and causes amplification of podosomes in mouse peritoneal macrophages.
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Affiliation(s)
- Wei Chen
- Houston Methodist Research Institute, Houston, TX, USA; Department of Nephrology, Second Xiangya Hospital, Central South University, Changsha 410011, China
| | - Rafik M Ghobrial
- Houston Methodist Research Institute, Houston, TX, USA; Weill Cornell Medical College, 407 E 61st St, New York, USA
| | - Xian C Li
- Houston Methodist Research Institute, Houston, TX, USA; Weill Cornell Medical College, 407 E 61st St, New York, USA
| | - Malgorzata Kloc
- Houston Methodist Research Institute, Houston, TX, USA; Weill Cornell Medical College, 407 E 61st St, New York, USA; University of Texas, MD Anderson Cancer Center, Department of Genetics, Houston, TX, USA.
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6
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Hood AR, Ai X, Pogwizd SM. Regulation of cardiac gap junctions by protein phosphatases. J Mol Cell Cardiol 2017; 107:52-57. [PMID: 28478048 DOI: 10.1016/j.yjmcc.2017.05.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Revised: 04/13/2017] [Accepted: 05/02/2017] [Indexed: 01/16/2023]
Abstract
Sufficient connexin-mediated intercellular coupling is critical to maintain gap junctional communication for proper cardiac function. Alterations in connexin phosphorylation state, particularly dephosphorylation of connexin 43 (Cx43), may impact cell coupling and conduction in disease states. Cx43 dephosphorylation may be carried out by protein phosphatase activity. Here, we present an overview of the key phosphatases known to interact with Cx43 or modulators of Cx43, as well as some possible therapeutic targets to regulate phosphatase activity in the heart.
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Affiliation(s)
- Ashleigh R Hood
- Department of Biomedical Engineering, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Xun Ai
- Department of Biophysics and Physiology, Rush University, Chicago, IL, United States
| | - Steven M Pogwizd
- Department of Biomedical Engineering, University of Alabama at Birmingham, Birmingham, AL, United States; Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States.
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Prasad EM, Mopuri R, Islam MS, Kodidhela LD. Cardioprotective effect of Vitex negundo on isoproterenol-induced myocardial necrosis in wistar rats: A dual approach study. Biomed Pharmacother 2017; 85:601-610. [DOI: 10.1016/j.biopha.2016.11.069] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Revised: 11/13/2016] [Accepted: 11/14/2016] [Indexed: 12/18/2022] Open
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8
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Han J, Weisbrod RM, Shao D, Watanabe Y, Yin X, Bachschmid MM, Seta F, Janssen-Heininger YMW, Matsui R, Zang M, Hamburg NM, Cohen RA. The redox mechanism for vascular barrier dysfunction associated with metabolic disorders: Glutathionylation of Rac1 in endothelial cells. Redox Biol 2016; 9:306-319. [PMID: 27693992 PMCID: PMC5045950 DOI: 10.1016/j.redox.2016.09.003] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Revised: 09/08/2016] [Accepted: 09/09/2016] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Oxidative stress is implicated in increased vascular permeability associated with metabolic disorders, but the underlying redox mechanism is poorly defined. S-glutathionylation, a stable adduct of glutathione with protein sulfhydryl, is a reversible oxidative modification of protein and is emerging as an important redox signaling paradigm in cardiovascular physiopathology. The present study determines the role of protein S-glutathionylation in metabolic stress-induced endothelial cell permeability. METHODS AND RESULTS In endothelial cells isolated from patients with type-2 diabetes mellitus, protein S-glutathionylation level was increased. This change was also observed in aortic endothelium in ApoE deficient (ApoE-/-) mice fed on Western diet. Metabolic stress-induced protein S-glutathionylation in human aortic endothelial cells (HAEC) was positively correlated with elevated endothelial cell permeability, as reflected by disassembly of cell-cell adherens junctions and cortical actin structures. These impairments were reversed by adenoviral overexpression of a specific de-glutathionylation enzyme, glutaredoxin-1 in cultured HAECs. Consistently, transgenic overexpression of human Glrx-1 in ApoE-/- mice fed the Western diet attenuated endothelial protein S-glutathionylation, actin cytoskeletal disorganization, and vascular permeability in the aorta. Mechanistically, glutathionylation and inactivation of Rac1, a small RhoGPase, were associated with endothelial hyperpermeability caused by metabolic stress. Glutathionylation of Rac1 on cysteine 81 and 157 located adjacent to guanine nucleotide binding site was required for the metabolic stress to inhibit Rac1 activity and promote endothelial hyperpermeability. CONCLUSIONS Glutathionylation and inactivation of Rac1 in endothelial cells represent a novel redox mechanism of vascular barrier dysfunction associated with metabolic disorders.
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Affiliation(s)
- Jingyan Han
- Vascular Biology Section, Evans Department of Medicine, Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, USA.
| | - Robert M Weisbrod
- Evans Department of Medicine and the Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, USA
| | - Di Shao
- Vascular Biology Section, Evans Department of Medicine, Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, USA
| | - Yosuke Watanabe
- Vascular Biology Section, Evans Department of Medicine, Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, USA
| | - Xiaoyan Yin
- Framingham Heart Study, Boston University School of Medicine, Boston, MA, USA
| | - Markus M Bachschmid
- Vascular Biology Section, Evans Department of Medicine, Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, USA
| | - Francesca Seta
- Vascular Biology Section, Evans Department of Medicine, Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, USA
| | | | - Reiko Matsui
- Vascular Biology Section, Evans Department of Medicine, Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, USA
| | - Mengwei Zang
- Department of Molecular Medicine, Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center, South Texas Veterans Health Care System, San Antonio, TX, USA
| | - Naomi M Hamburg
- Evans Department of Medicine and the Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, USA
| | - Richard A Cohen
- Vascular Biology Section, Evans Department of Medicine, Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, USA
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