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Achi SC, McGrosso D, Tocci S, Ibeawuchi SR, Sayed IM, Gonzalez DJ, Das S. Proteome profiling identifies a link between the mitochondrial pathways and host-microbial sensor ELMO1 following Salmonella infection. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.03.592405. [PMID: 38746404 PMCID: PMC11092768 DOI: 10.1101/2024.05.03.592405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
The host EnguLfment and cell MOtility protein 1 (ELMO1) is a cytosolic microbial sensor that facilitates bacterial sensing, internalization, clearance, and inflammatory responses. We have shown previously that ELMO1 binds bacterial effector proteins, including pathogenic effectors from Salmonella and controls host innate immune signaling. To understand the ELMO1-regulated host pathways, we have performed liquid chromatography Multinotch MS3-Tandem Mass Tag (TMT) multiplexed proteomics to determine the global quantification of proteins regulated by ELMO1 in macrophages during Salmonella infection. Comparative proteome analysis of control and ELMO1-depleted murine J774 macrophages after Salmonella infection quantified more than 7000 proteins with a notable enrichment in mitochondrial-related proteins. Gene ontology enrichment analysis revealed 19 upregulated and 11 downregulated proteins exclusive to ELMO1-depleted cells during infection, belonging to mitochondrial functions, metabolism, vesicle transport, and the immune system. By assessing the cellular energetics via Seahorse analysis, we found that Salmonella infection alters mitochondrial metabolism, shifting it from oxidative phosphorylation to glycolysis. Importantly, these metabolic changes are significantly influenced by the depletion of ELMO1. Furthermore, ELMO1 depletion resulted in a decreased ATP rate index following Salmonella infection, indicating its importance in counteracting the effects of Salmonella on immunometabolism. Among the proteins involved in mitochondrial pathways, mitochondrial fission protein DRP1 was significantly upregulated in ELMO1-depleted cells and in ELMO1-KO mice intestine following Salmonella infection. Pharmacological Inhibition of DRP1 revealed the link of the ELMO1-DRP1 pathway in regulating the pro-inflammatory cytokine TNF-α following infection. The role of ELMO1 has been further characterized by a proteome profile of ELMO1-depleted macrophage infected with SifA mutant and showed the involvement of ELMO1-SifA on mitochondrial function, metabolism and host immune/defense responses. Collectively, these findings unveil a novel role for ELMO1 in modulating mitochondrial functions, potentially pivotal in modulating inflammatory responses. Significance Statement Host microbial sensing is critical in infection and inflammation. Among these sensors, ELMO1 has emerged as a key regulator, finely tuning innate immune signaling and discriminating between pathogenic and non-pathogenic bacteria through interactions with microbial effectors like SifA of Salmonella . In this study, we employed Multinotch MS3-Tandem Mass Tag (TMT) multiplexed proteomics to determine the proteome alterations mediated by ELMO1 in macrophages following WT and SifA mutant Salmonella infection. Our findings highlight a substantial enrichment of host proteins associated with metabolic pathways and mitochondrial functions. Notably, we validated the mitochondrial fission protein DRP1 that is upregulated in ELMO1-depleted macrophages and in ELMO1 knockout mice intestine after infection. Furthermore, we demonstrated that Salmonella -induced changes in cellular energetics are influenced by the presence of ELMO1. This work shed light on a possible novel link between mitochondrial dynamics and microbial sensing in modulating immune responses.
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Anandachar MS, Roy S, Sinha S, Boadi A, Katkar GD, Ghosh P. Diverse gut pathogens exploit the host engulfment pathway via a conserved mechanism. J Biol Chem 2023; 299:105390. [PMID: 37890785 PMCID: PMC10696401 DOI: 10.1016/j.jbc.2023.105390] [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: 06/30/2023] [Revised: 09/22/2023] [Accepted: 10/15/2023] [Indexed: 10/29/2023] Open
Abstract
Macrophages clear infections by engulfing and digesting pathogens within phagolysosomes. Pathogens escape this fate by engaging in a molecular arms race; they use WxxxE motif-containing "effector" proteins to subvert the host cells they invade and seek refuge within protective vacuoles. Here, we define the host component of the molecular arms race as an evolutionarily conserved polar "hot spot" on the PH domain of ELMO1 (Engulfment and Cell Motility protein 1), which is targeted by diverse WxxxE effectors. Using homology modeling and site-directed mutagenesis, we show that a lysine triad within the "patch" directly binds all WxxxE effectors tested: SifA (Salmonella), IpgB1 and IpgB2 (Shigella), and Map (enteropathogenic Escherichia coli). Using an integrated SifA-host protein-protein interaction network, in silico network perturbation, and functional studies, we show that the major consequences of preventing SifA-ELMO1 interaction are reduced Rac1 activity and microbial invasion. That multiple effectors of diverse structure, function, and sequence bind the same hot spot on ELMO1 suggests that the WxxxE effector(s)-ELMO1 interface is a convergence point of intrusion detection and/or host vulnerability. We conclude that the interface may represent the fault line in coevolved molecular adaptations between pathogens and the host, and its disruption may serve as a therapeutic strategy.
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Affiliation(s)
- Mahitha Shree Anandachar
- Department of Cellular and Molecular Medicine, University of California San Diego, San Diego, California, USA; Department of Pathology, University of California San Diego, San Diego, California, USA
| | - Suchismita Roy
- Department of Cellular and Molecular Medicine, University of California San Diego, San Diego, California, USA
| | - Saptarshi Sinha
- Department of Cellular and Molecular Medicine, University of California San Diego, San Diego, California, USA
| | - Agyekum Boadi
- Department of Cellular and Molecular Medicine, University of California San Diego, San Diego, California, USA
| | - Gajanan D Katkar
- Department of Cellular and Molecular Medicine, University of California San Diego, San Diego, California, USA.
| | - Pradipta Ghosh
- Department of Cellular and Molecular Medicine, University of California San Diego, San Diego, California, USA; Department of Medicine, University of California San Diego, San Diego, California, USA.
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Doan RA, Monk KR. Dock1 acts cell-autonomously in Schwann cells to regulate the development, maintenance, and repair of peripheral myelin. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.26.564271. [PMID: 37961336 PMCID: PMC10634861 DOI: 10.1101/2023.10.26.564271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Schwann cells, the myelinating glia of the peripheral nervous system (PNS), are critical for myelin development, maintenance, and repair. Rac1 is a known regulator of radial sorting, a key step in developmental myelination, and we previously showed in zebrafish that loss of Dock1, a Rac1-specific guanine nucleotide exchange factor, results in delayed peripheral myelination in development. We demonstrate here that Dock1 is necessary for myelin maintenance and remyelination after injury in adult zebrafish. Furthermore, it performs an evolutionary conserved role in mice, acting cell-autonomously in Schwann cells to regulate peripheral myelin development, maintenance, and repair. Additionally, manipulating Rac1 levels in larval zebrafish reveals that dock1 mutants are sensitized to inhibition of Rac1, suggesting an interaction between the two proteins during PNS development. We propose that the interplay between Dock1 and Rac1 signaling in Schwann cells is required to establish, maintain, and facilitate repair and remyelination within the peripheral nervous system.
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Affiliation(s)
- Ryan A Doan
- The Vollum Institute, Oregon Health & Science University, Portland, OR, USA
| | - Kelly R Monk
- The Vollum Institute, Oregon Health & Science University, Portland, OR, USA
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Anandachar MS, Roy S, Sinha S, Agyekum B, Ibeawuchi SR, Gementera H, Amamoto A, Katkar GD, Ghosh P. Diverse Gut Pathogens Exploit the Host Engulfment Pathway via a Conserved Mechanism. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.09.536168. [PMID: 37066267 PMCID: PMC10104235 DOI: 10.1101/2023.04.09.536168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/18/2023]
Abstract
Macrophages clear infections by engulfing and digesting pathogens within phagolysosomes. Pathogens escape this fate by engaging in a molecular arms race; they use WxxxE motif-containing effector proteins to subvert the host cells they invade and seek refuge within protective vacuoles. Here we define the host component of the molecular arms race as an evolutionarily conserved polar hotspot on the PH-domain of ELMO1 (Engulfment and Cell Motility1), which is targeted by diverse WxxxE-effectors. Using homology modeling and site-directed mutagenesis, we show that a lysine triad within the patch directly binds all WxxxE-effectors tested: SifA (Salmonella), IpgB1 and IpgB2 (Shigella), and Map (enteropathogenic E. coli). Using an integrated SifA-host protein-protein interaction (PPI) network, in-silico network perturbation, and functional studies we show that the major consequences of preventing SifA-ELMO1 interaction are reduced Rac1 activity and microbial invasion. That multiple effectors of diverse structure, function, and sequence bind the same hotpot on ELMO1 suggests that the WxxxE-effector(s)-ELMO1 interface is a convergence point of intrusion detection and/or host vulnerability. We conclude that the interface may represent the fault line in co-evolved molecular adaptations between pathogens and the host and its disruption may serve as a therapeutic strategy.
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Boland A, Côté J, Barford D. Structural biology of DOCK-family guanine nucleotide exchange factors. FEBS Lett 2023; 597:794-810. [PMID: 36271211 PMCID: PMC10152721 DOI: 10.1002/1873-3468.14523] [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: 08/24/2022] [Revised: 10/10/2022] [Accepted: 10/11/2022] [Indexed: 11/09/2022]
Abstract
DOCK proteins are a family of multi-domain guanine nucleotide exchange factors (GEFs) that activate the RHO GTPases CDC42 and RAC1, thereby regulating several RHO GTPase-dependent cellular processes. DOCK proteins are characterized by the catalytic DHR2 domain (DOCKDHR2 ), and a phosphatidylinositol(3,4,5)P3 -binding DHR1 domain (DOCKDHR1 ) that targets DOCK proteins to plasma membranes. DOCK-family GEFs are divided into four subfamilies (A to D) differing in their specificities for CDC42 and RAC1, and the composition of accessory signalling domains. Additionally, the DOCK-A and DOCK-B subfamilies are constitutively associated with ELMO proteins that auto-inhibit DOCK GEF activity. We review structural studies that have provided mechanistic insights into DOCK-protein functions. These studies revealed how a conserved nucleotide sensor in DOCKDHR2 catalyses nucleotide exchange, the basis for how different DOCK proteins activate specifically CDC42 and RAC1, and sometimes both, and how up-stream regulators relieve the ELMO-mediated auto-inhibition. We conclude by presenting a model for full-length DOCK9 of the DOCK-D subfamily. The involvement of DOCK GEFs in a range of diseases highlights the importance of gaining structural insights into these proteins to better understand and specifically target them.
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Affiliation(s)
- Andreas Boland
- Department of Molecular and Cellular BiologyUniversity of GenevaSwitzerland
| | - Jean‐Francois Côté
- Montreal Clinical Research Institute (IRCM)Canada
- Department of Medicine and Department of Biochemistry and Molecular MedicineUniversité de MontréalCanada
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Fu X, Guo M, Liu J, Li C. circRNA432 enhances the coelomocyte phagocytosis via regulating the miR-2008-ELMO1 axis in Vibrio splendidus-challenged Apostichopus japonicus. Commun Biol 2023; 6:115. [PMID: 36709365 PMCID: PMC9884281 DOI: 10.1038/s42003-023-04516-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 01/20/2023] [Indexed: 01/30/2023] Open
Abstract
Circular RNAs (circRNAs) are a kind of extensive and diverse covalently closed circular endogenous RNA, which exert crucial functions in immune regulation in mammals. However, the functions and mechanisms of circRNAs in invertebrates are largely unclarified. In our previous work, 261 differentially expressed circRNAs including circRNA432 (circ432) were identified from skin ulcer syndrome (SUS) diseased sea cucumber Apostichopus japonicus by RNA-seq. To better address the functional role of sea cucumber circRNAs, circ432 was first found to be significantly induced by Vibrio splendidus challenge and LPS exposure in this study. Knock-down circ432 could depress the V. splendidus-induced coelomocytes phagocytosis. Moreover, circ432 is validated to serve as the sponge of miR-2008, a differential expressed miRNA in SUS-diseased sea cucumbers, by Argonaute 2-RNA immunoprecipitation (AGO2-RIP) assay, luciferase reporter assay and RNA fluorescence in situ hybridization (FISH) in vitro. Engulfment and cell motility protein 1 (AjELMO1) is further demonstrated to be the target of miR-2008, and silencing AjELMO1 inhibits the V. splendidus-induced coelomocytes phagocytosis, and this phenomenon could be further suppressed by supplementing with miR-2008 mimics, suggesting that circ432 might regulate coelomocytes phagocytosis via miR-2008-AjELMO1 axis. We further confirm that the depressed coelomocytes' phagocytosis by circ432 silencing is consistent with the decreased abundance of AjELMO1, and could be recovered by miR-2008 inhibitors transfection. All our results provide the evidence that circ432 is involved in regulating pathogen-induced coelomocyte phagocytosis via sponge miR-2008 and promotes the abundance of AjELMO1. These findings will enrich the regulatory mechanism of phagocytosis in echinoderm and provide theoretical data for SUS disease prevention and control in sea cucumbers.
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Affiliation(s)
- Xianmu Fu
- grid.203507.30000 0000 8950 5267State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Ningbo University, 315211 Ningbo, P. R. China
| | - Ming Guo
- grid.203507.30000 0000 8950 5267State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Ningbo University, 315211 Ningbo, P. R. China
| | - Jiqing Liu
- grid.203507.30000 0000 8950 5267State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Ningbo University, 315211 Ningbo, P. R. China
| | - Chenghua Li
- grid.203507.30000 0000 8950 5267State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Ningbo University, 315211 Ningbo, P. R. China ,grid.484590.40000 0004 5998 3072Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, 266071 Qingdao, P. R. China
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Morioka S, Kajioka D, Yamaoka Y, Ellison RM, Tufan T, Werkman IL, Tanaka S, Barron B, Ito ST, Kucenas S, Okusa MD, Ravichandran KS. Chimeric efferocytic receptors improve apoptotic cell clearance and alleviate inflammation. Cell 2022; 185:4887-4903.e17. [PMID: 36563662 PMCID: PMC9930200 DOI: 10.1016/j.cell.2022.11.029] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Revised: 10/03/2022] [Accepted: 11/24/2022] [Indexed: 12/24/2022]
Abstract
Our bodies turn over billions of cells daily via apoptosis and are in turn cleared by phagocytes via the process of "efferocytosis." Defects in efferocytosis are now linked to various inflammatory diseases. Here, we designed a strategy to boost efferocytosis, denoted "chimeric receptor for efferocytosis" (CHEF). We fused a specific signaling domain within the cytoplasmic adapter protein ELMO1 to the extracellular phosphatidylserine recognition domains of the efferocytic receptors BAI1 or TIM4, generating BELMO and TELMO, respectively. CHEF-expressing phagocytes display a striking increase in efferocytosis. In mouse models of inflammation, BELMO expression attenuates colitis, hepatotoxicity, and nephrotoxicity. In mechanistic studies, BELMO increases ER-resident enzymes and chaperones to overcome protein-folding-associated toxicity, which was further validated in a model of ER-stress-induced renal ischemia-reperfusion injury. Finally, TELMO introduction after onset of kidney injury significantly reduced fibrosis. Collectively, these data advance a concept of chimeric efferocytic receptors to boost efferocytosis and dampen inflammation.
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Affiliation(s)
- Sho Morioka
- The Center for Cell Clearance, University of Virginia, Charlottesville, VA, USA; Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA; Department of Medicine, Division of Nephrology and Center for Immunity, Inflammation and Regenerative Medicine (CIIR), University of Virginia, Charlottesville, VA, USA; Preemptive Food Research Center (PFRC), Gifu University Institute for Advanced Study, Gifu, Japan.
| | - Daiki Kajioka
- Department of Medicine, Division of Nephrology and Center for Immunity, Inflammation and Regenerative Medicine (CIIR), University of Virginia, Charlottesville, VA, USA
| | - Yusuke Yamaoka
- Department of Medicine, Division of Nephrology and Center for Immunity, Inflammation and Regenerative Medicine (CIIR), University of Virginia, Charlottesville, VA, USA; Department of Parasitology and Infectious Diseases, Gifu University Graduate School of Medicine, Gifu, Japan
| | - Rochelle M Ellison
- Division of Immunobiology, Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA
| | - Turan Tufan
- The Center for Cell Clearance, University of Virginia, Charlottesville, VA, USA; Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA; Department of Computational Biology and Medical Science, Graduate School of Frontier Science, University of Tokyo, Tokyo, Japan
| | - Inge L Werkman
- Department of Biology, University of Virginia, Charlottesville, VA, USA
| | - Shinji Tanaka
- Department of Medicine, Division of Nephrology and Center for Immunity, Inflammation and Regenerative Medicine (CIIR), University of Virginia, Charlottesville, VA, USA
| | - Brady Barron
- The Center for Cell Clearance, University of Virginia, Charlottesville, VA, USA; Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA; Division of Immunobiology, Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA
| | - Satoshi T Ito
- Department of Medicine, Division of Nephrology and Center for Immunity, Inflammation and Regenerative Medicine (CIIR), University of Virginia, Charlottesville, VA, USA; Department of Computational Biology and Medical Science, Graduate School of Frontier Science, University of Tokyo, Tokyo, Japan
| | - Sarah Kucenas
- Department of Biology, University of Virginia, Charlottesville, VA, USA
| | - Mark D Okusa
- Department of Medicine, Division of Nephrology and Center for Immunity, Inflammation and Regenerative Medicine (CIIR), University of Virginia, Charlottesville, VA, USA
| | - Kodi S Ravichandran
- The Center for Cell Clearance, University of Virginia, Charlottesville, VA, USA; Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA; VIB/UGent Inflammation Research Centre, Biomedical Molecular Biology, Ghent University, Ghent, Belgium; Division of Immunobiology, Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA.
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8
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Tran V, Nahlé S, Robert A, Desanlis I, Killoran R, Ehresmann S, Thibault MP, Barford D, Ravichandran KS, Sauvageau M, Smith MJ, Kmita M, Côté JF. Biasing the conformation of ELMO2 reveals that myoblast fusion can be exploited to improve muscle regeneration. Nat Commun 2022; 13:7077. [PMID: 36400788 PMCID: PMC9674853 DOI: 10.1038/s41467-022-34806-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 11/08/2022] [Indexed: 11/21/2022] Open
Abstract
Myoblast fusion is fundamental for the development of multinucleated myofibers. Evolutionarily conserved proteins required for myoblast fusion include RAC1 and its activator DOCK1. In the current study we analyzed the contribution of the DOCK1-interacting ELMO scaffold proteins to myoblast fusion. When Elmo1-/- mice underwent muscle-specific Elmo2 genetic ablation, they exhibited severe myoblast fusion defects. A mutation in the Elmo2 gene that reduced signaling resulted in a decrease in myoblast fusion. Conversely, a mutation in Elmo2 coding for a protein with an open conformation increased myoblast fusion during development and in muscle regeneration. Finally, we showed that the dystrophic features of the Dysferlin-null mice, a model of limb-girdle muscular dystrophy type 2B, were reversed when expressing ELMO2 in an open conformation. These data provide direct evidence that the myoblast fusion process could be exploited for regenerative purposes and improve the outcome of muscle diseases.
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Affiliation(s)
- Viviane Tran
- Montreal Clinical Research Institute (IRCM), Montreal, QC, H2W 1R7, Canada
- Department of Biochemistry and Molecular Medicine, Université de Montréal, Montreal, QC, H3C 3J7, Canada
| | - Sarah Nahlé
- Montreal Clinical Research Institute (IRCM), Montreal, QC, H2W 1R7, Canada
- Molecular Biology Programs, Université de Montréal, Montréal, QC, H3T 1J4, Canada
| | - Amélie Robert
- Montreal Clinical Research Institute (IRCM), Montreal, QC, H2W 1R7, Canada
| | - Inès Desanlis
- Montreal Clinical Research Institute (IRCM), Montreal, QC, H2W 1R7, Canada
- Department of Medicine, Université de Montréal, Montreal, QC, H3C 3J7, Canada
| | - Ryan Killoran
- Institute for Research in Immunology and Cancer, Université de Montréal, Montreal, QC, H3T 1J4, Canada
| | - Sophie Ehresmann
- Montreal Clinical Research Institute (IRCM), Montreal, QC, H2W 1R7, Canada
- Molecular Biology Programs, Université de Montréal, Montréal, QC, H3T 1J4, Canada
| | | | - David Barford
- MRC Laboratory of Molecular Biology, Cambridge, CB2 OQH, UK
| | - Kodi S Ravichandran
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, 22908, VA, USA
- VIB/UGent Inflammation Research Centre, Biomedical Molecular Biology, Ghent University, 9052, Ghent, Belgium
| | - Martin Sauvageau
- Montreal Clinical Research Institute (IRCM), Montreal, QC, H2W 1R7, Canada
- Department of Biochemistry and Molecular Medicine, Université de Montréal, Montreal, QC, H3C 3J7, Canada
- Molecular Biology Programs, Université de Montréal, Montréal, QC, H3T 1J4, Canada
- Department of Biochemistry, McGill University, Montréal, QC, H3G 1Y6, Canada
| | - Matthew J Smith
- Institute for Research in Immunology and Cancer, Université de Montréal, Montreal, QC, H3T 1J4, Canada
- Department of Pathology and Cell Biology, Université de Montréal, Montreal, QC, H3C 3J7, Canada
| | - Marie Kmita
- Montreal Clinical Research Institute (IRCM), Montreal, QC, H2W 1R7, Canada
- Molecular Biology Programs, Université de Montréal, Montréal, QC, H3T 1J4, Canada
- Department of Medicine, Université de Montréal, Montreal, QC, H3C 3J7, Canada
- Department of Experimental Medicine, McGill University, Montréal, QC, H3G 2M1, Canada
| | - Jean-François Côté
- Montreal Clinical Research Institute (IRCM), Montreal, QC, H2W 1R7, Canada.
- Department of Biochemistry and Molecular Medicine, Université de Montréal, Montreal, QC, H3C 3J7, Canada.
- Molecular Biology Programs, Université de Montréal, Montréal, QC, H3T 1J4, Canada.
- Department of Medicine, Université de Montréal, Montreal, QC, H3C 3J7, Canada.
- Department of Anatomy and Cell Biology, McGill University, Montréal, QC, H3A 0C7, Canada.
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Actin Up: An Overview of the Rac GEF Dock1/Dock180 and Its Role in Cytoskeleton Rearrangement. Cells 2022; 11:cells11223565. [PMID: 36428994 PMCID: PMC9688060 DOI: 10.3390/cells11223565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 10/27/2022] [Accepted: 11/10/2022] [Indexed: 11/16/2022] Open
Abstract
Dock1, originally Dock180, was the first identified member of the Dock family of GTPase Exchange Factors. Early biochemical and genetic studies of Dock180 elucidated the functions and regulation of Dock180 and informed our understanding of all Dock family members. Dock180 activates Rac to stimulate actin polymerization in response to signals initiated by a variety of receptors. Dock180 dependent Rac activation is essential for processes such as apoptotic cell engulfment, myoblast fusion, and cell migration during development and homeostasis. Inappropriate Dock180 activity has been implicated in cancer invasion and metastasis and in the uptake of bacterial pathogens. Here, we give an overview of the history and current understanding of the activity, regulation, and impacts of Dock180.
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Boger M, Bennewitz K, Wohlfart DP, Hausser I, Sticht C, Poschet G, Kroll J. Comparative Morphological, Metabolic and Transcriptome Analyses in elmo1−/−, elmo2−/−, and elmo3−/− Zebrafish Mutants Identified a Functional Non-Redundancy of the Elmo Proteins. Front Cell Dev Biol 2022; 10:918529. [PMID: 35874819 PMCID: PMC9304559 DOI: 10.3389/fcell.2022.918529] [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: 04/12/2022] [Accepted: 06/13/2022] [Indexed: 11/13/2022] Open
Abstract
The ELMO protein family consists of the homologues ELMO1, ELMO2 and ELMO3. Several studies have shown that the individual ELMO proteins are involved in a variety of cellular and developmental processes. However, it has poorly been understood whether the Elmo proteins show similar functions and act redundantly. To address this question, elmo1−/−, elmo2−/− and elmo3−/− zebrafish were generated and a comprehensive comparison of the phenotypic changes in organ morphology, transcriptome and metabolome was performed in these mutants. The results showed decreased fasting and increased postprandial blood glucose levels in adult elmo1−/−, as well as a decreased vascular formation in the adult retina in elmo1−/−, but an increased vascular formation in the adult elmo3−/− retina. The phenotypical comparison provided few similarities, as increased Bowman space areas in adult elmo1−/− and elmo2−/− kidneys, an increased hyaloid vessel diameter in elmo1−/− and elmo3−/− and a transcriptional downregulation of the vascular development in elmo1−/−, elmo2−/−, and elmo3−/− zebrafish larvae. Besides this, elmo1−/−, elmo2−/−, and elmo3−/− zebrafish exhibited several distinct changes in the vascular and glomerular structure and in the metabolome and the transcriptome. Especially, elmo3−/− zebrafish showed extensive differences in the larval transcriptome and an impaired survivability. Together, the data demonstrated that the three zebrafish Elmo proteins regulate not only similar but also divergent biological processes and mechanisms and show a low functional redundancy.
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Affiliation(s)
- Mike Boger
- Department of Vascular Biology and Tumor Angiogenesis, European Center for Angioscience (ECAS), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Katrin Bennewitz
- Department of Vascular Biology and Tumor Angiogenesis, European Center for Angioscience (ECAS), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - David Philipp Wohlfart
- Department of Vascular Biology and Tumor Angiogenesis, European Center for Angioscience (ECAS), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Ingrid Hausser
- Institute of Pathology IPH, EM Lab, Heidelberg University Hospital, Heidelberg, Germany
| | - Carsten Sticht
- NGS Core Facility, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Gernot Poschet
- Metabolomics Core Technology Platform, Centre for Organismal Studies, Heidelberg University, Heidelberg, Germany
| | - Jens Kroll
- Department of Vascular Biology and Tumor Angiogenesis, European Center for Angioscience (ECAS), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
- *Correspondence: Jens Kroll,
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Tocci S, Ibeawuchi SR, Das S, Sayed IM. Role of ELMO1 in inflammation and cancer-clinical implications. Cell Oncol (Dordr) 2022; 45:505-525. [PMID: 35668246 DOI: 10.1007/s13402-022-00680-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/19/2022] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND Engulfment and cell motility protein 1 (ELMO1) is a key protein for innate immunity since it is required for the clearance of apoptotic cells and pathogenic bacteria as well as for the control of inflammatory responses. ELMO1, through binding with Dock180 and activation of the Rac1 signaling pathway, plays a significant role in cellular shaping and motility. Rac-mediated actin cytoskeletal rearrangement is essential for bacterial phagocytosis, but also plays a crucial role in processes such as cancer cell invasion and metastasis. While the role of ELMO1 in bacterial infection and inflammatory responses is well established, its implication in cancer is not widely explored yet. Molecular changes or epigenetic alterations such as DNA methylation, which ultimately leads to alterations in gene expression and deregulation of cellular signaling, has been reported for ELMO1 in different cancer types. CONCLUSIONS In this review, we provide an updated and comprehensive summary of the roles of ELMO1 in infection, inflammatory diseases and cancer. We highlight the possible mechanisms regulated by ELMO1 that are relevant for cancer development and progression and provide insight into the possible use of ELMO1 as a diagnostic biomarker and therapeutic target.
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Affiliation(s)
- Stefania Tocci
- Department of Pathology, University of California San Diego, La Jolla, CA, USA
| | | | - Soumita Das
- Department of Pathology, University of California San Diego, La Jolla, CA, USA.
| | - Ibrahim M Sayed
- Department of Pathology, University of California San Diego, La Jolla, CA, USA. .,Department of Medical Microbiology and Immunology, Faculty of Medicine, Assiut University, Assiut, Egypt.
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Sayed IM, Ibeawuchi SR, Lie D, Anandachar MS, Pranadinata R, Raffatellu M, Das S. The interaction of enteric bacterial effectors with the host engulfment pathway control innate immune responses. Gut Microbes 2022; 13:1991776. [PMID: 34719317 PMCID: PMC8565811 DOI: 10.1080/19490976.2021.1991776] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Host engulfment protein ELMO1 generates intestinal inflammation following internalization of enteric bacteria. In Shigella, bacterial effector IpgB1 interacts with ELMO1 and promotes bacterial invasion. IpgB1 belongs to the WxxxE effector family, a motif found in several effectors of enteric pathogens. Here, we have studied the role of WxxxE effectors, with emphasis on Salmonella SifA and whether it interacts with ELMO1 to regulate inflammation. In-silico-analysis of WxxxE effectors was performed using BLAST search and Clustal W program. The interaction of ELMO1 with SifA was assessed by GST pulldown assay and co-immunoprecipitation. ELMO1 knockout mice, and ELMO1-depleted murine macrophage J774 cell lines were challenged with WT and SifA mutant Salmonella. Bacterial effectors containing the WxxxE motif were transfected in WT and ELMO1-depleted J774 cells to assess the inflammatory cytokines. ELMO1 generates differential pro-inflammatory cytokines between pathogenic and nonpathogenic bacteria. WxxxE motif is present in pathogens and in the TIR domain of host proteins. The C-terminal part of ELMO1 interacts with SifA where WxxxE motif is important for interaction. ELMO1-SifA interaction affects bacterial colonization, dissemination, and inflammatory cytokines in vivo. Moreover, ELMO1-SifA interaction increases TNF-α and IL-6 production from the macrophage cell line and is associated with enhanced Rac1 activity. ELMO1 also interacts with WxxxE effectors IpgB1, IpgB2, and Map and induces inflammation after challenge with microbes or microbial ligands. ELMO1 generates a differential response through interaction with the WxxxE motif, which is absent in commensals. ELMO1-WxxxE interaction plays a role in bacterial pathogenesis and induction of inflammatory response.
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Affiliation(s)
- Ibrahim M Sayed
- Department of Pathology, University of California San Diego, La Jolla, CA, USA
| | | | - Dominique Lie
- Department of Pathology, University of California San Diego, La Jolla, CA, USA
| | | | - Rama Pranadinata
- Department of Pathology, University of California San Diego, La Jolla, CA, USA
| | - Manuela Raffatellu
- Department of Pediatrics, Division of Host-Microbe Systems and Therapeutics, University of California San Diego, LA Jolla, CA, USA,Center for Mucosal Immunology, Chiba University-UC San Diego, La Jolla, CAUSA
| | - Soumita Das
- Department of Pathology, University of California San Diego, La Jolla, CA, USA,CONTACT Soumita Das Department of Pathology, University of California, San Diego, 9500 Gilman Drive, Mc 0644, George Palade Laboratory, Office Rm 256, San Diego, Ca, 92093-0644, USA
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13
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Kukimoto-Niino M, Ihara K, Murayama K, Shirouzu M. Structural insights into the small GTPase specificity of the DOCK guanine nucleotide exchange factors. Curr Opin Struct Biol 2021; 71:249-258. [PMID: 34507037 DOI: 10.1016/j.sbi.2021.08.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 08/02/2021] [Accepted: 08/06/2021] [Indexed: 10/20/2022]
Abstract
The dedicator of cytokinesis (DOCK) family of guanine nucleotide exchange factors (GEFs) regulates cytoskeletal dynamics by activating the GTPases Rac and/or Cdc42. Eleven human DOCK proteins play various important roles in developmental processes and the immune system. Of these, DOCK1-5 proteins bind to engulfment and cell motility (ELMO) proteins to perform their physiological functions. Recent structural studies have greatly enhanced our understanding of the complex and diverse mechanisms of DOCK GEF activity and GTPase recognition and its regulation by ELMO. This review is focused on gaining structural insights into the substrate specificity of the DOCK GEFs, and discuss how Rac and Cdc42 are specifically recognized by the catalytic DHR-2 and surrounding domains of DOCK or binding partners.
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Affiliation(s)
- Mutsuko Kukimoto-Niino
- Laboratory for Protein Functional and Structural Biology, RIKEN Center for Biosystems Dynamics Research, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
| | - Kentaro Ihara
- Laboratory for Protein Functional and Structural Biology, RIKEN Center for Biosystems Dynamics Research, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
| | - Kazutaka Murayama
- Laboratory for Protein Functional and Structural Biology, RIKEN Center for Biosystems Dynamics Research, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan; Graduate School of Biomedical Engineering, Tohoku University, 2-1 Seiryo, Aoba-ku, Sendai, Miyagi 980-8575, Japan
| | - Mikako Shirouzu
- Laboratory for Protein Functional and Structural Biology, RIKEN Center for Biosystems Dynamics Research, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan.
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14
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ELMO1 signaling is a promoter of osteoclast function and bone loss. Nat Commun 2021; 12:4974. [PMID: 34404802 PMCID: PMC8371122 DOI: 10.1038/s41467-021-25239-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Accepted: 07/28/2021] [Indexed: 01/02/2023] Open
Abstract
Osteoporosis affects millions worldwide and is often caused by osteoclast induced bone loss. Here, we identify the cytoplasmic protein ELMO1 as an important ‘signaling node’ in osteoclasts. We note that ELMO1 SNPs associate with bone abnormalities in humans, and that ELMO1 deletion in mice reduces bone loss in four in vivo models: osteoprotegerin deficiency, ovariectomy, and two types of inflammatory arthritis. Our transcriptomic analyses coupled with CRISPR/Cas9 genetic deletion identify Elmo1 associated regulators of osteoclast function, including cathepsin G and myeloperoxidase. Further, we define the ‘ELMO1 interactome’ in osteoclasts via proteomics and reveal proteins required for bone degradation. ELMO1 also contributes to osteoclast sealing zone on bone-like surfaces and distribution of osteoclast-specific proteases. Finally, a 3D structure-based ELMO1 inhibitory peptide reduces bone resorption in wild type osteoclasts. Collectively, we identify ELMO1 as a signaling hub that regulates osteoclast function and bone loss, with relevance to osteoporosis and arthritis. Osteoporosis and bone fractures affect millions of patients worldwide and are often due to increased bone resorption. Here the authors identify the cytoplasmic protein ELMO1 as an important ‘signaling node’ promoting the bone resorption function of osteoclasts.
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15
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Kukimoto-Niino M, Katsura K, Kaushik R, Ehara H, Yokoyama T, Uchikubo-Kamo T, Nakagawa R, Mishima-Tsumagari C, Yonemochi M, Ikeda M, Hanada K, Zhang KYJ, Shirouzu M. Cryo-EM structure of the human ELMO1-DOCK5-Rac1 complex. SCIENCE ADVANCES 2021; 7:7/30/eabg3147. [PMID: 34290093 PMCID: PMC8294757 DOI: 10.1126/sciadv.abg3147] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Accepted: 06/03/2021] [Indexed: 05/28/2023]
Abstract
The dedicator of cytokinesis (DOCK) family of guanine nucleotide exchange factors (GEFs) promotes cell motility, phagocytosis, and cancer metastasis through activation of Rho guanosine triphosphatases. Engulfment and cell motility (ELMO) proteins are binding partners of DOCK and regulate Rac activation. Here, we report the cryo-electron microscopy structure of the active ELMO1-DOCK5 complex bound to Rac1 at 3.8-Å resolution. The C-terminal region of ELMO1, including the pleckstrin homology (PH) domain, aids in the binding of the catalytic DOCK homology region 2 (DHR-2) domain of DOCK5 to Rac1 in its nucleotide-free state. A complex α-helical scaffold between ELMO1 and DOCK5 stabilizes the binding of Rac1. Mutagenesis studies revealed that the PH domain of ELMO1 enhances the GEF activity of DOCK5 through specific interactions with Rac1. The structure provides insights into how ELMO modulates the biochemical activity of DOCK and how Rac selectivity is achieved by ELMO.
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Affiliation(s)
- Mutsuko Kukimoto-Niino
- RIKEN Center for Biosystems Dynamics Research, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
| | - Kazushige Katsura
- RIKEN Center for Biosystems Dynamics Research, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
| | - Rahul Kaushik
- RIKEN Center for Biosystems Dynamics Research, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
| | - Haruhiko Ehara
- RIKEN Center for Biosystems Dynamics Research, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
| | - Takeshi Yokoyama
- RIKEN Center for Biosystems Dynamics Research, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
- Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan
| | - Tomomi Uchikubo-Kamo
- RIKEN Center for Biosystems Dynamics Research, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
| | - Reiko Nakagawa
- RIKEN Center for Biosystems Dynamics Research, 2-2-3 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan
| | - Chiemi Mishima-Tsumagari
- RIKEN Center for Biosystems Dynamics Research, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
| | - Mayumi Yonemochi
- RIKEN Center for Biosystems Dynamics Research, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
| | - Mariko Ikeda
- RIKEN Center for Biosystems Dynamics Research, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
| | - Kazuharu Hanada
- RIKEN Center for Biosystems Dynamics Research, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
| | - Kam Y J Zhang
- RIKEN Center for Biosystems Dynamics Research, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
| | - Mikako Shirouzu
- RIKEN Center for Biosystems Dynamics Research, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan.
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16
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Hashim IF, Ahmad Mokhtar AM. Small Rho GTPases and their associated RhoGEFs mutations promote immunological defects in primary immunodeficiencies. Int J Biochem Cell Biol 2021; 137:106034. [PMID: 34216756 DOI: 10.1016/j.biocel.2021.106034] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 06/14/2021] [Accepted: 06/28/2021] [Indexed: 01/10/2023]
Abstract
Primary immunodeficiencies (PIDs) are associated with deleterious mutations of genes that encode proteins involved in actin cytoskeleton reorganisation. This deficiency affects haematopoietic cells. PID results in the defective function of immune cells, such as impaired chemokine-induced motility, receptor signalling, development and maturation. Some of the genes mutated in PIDs are related to small Ras homologous (Rho) guanosine triphosphatase (GTPase), one of the families of the Ras superfamily. Most of these genes act as molecular switches by cycling between active guanosine triphosphate-bound and inactive guanosine diphosphate-bound forms to control multiple cellular functions. They are best studied for their role in promoting cytoskeleton reorganisation, cell adhesion and motility. Currently, only three small Rho GTPases, namely, Rac2, Cdc42 and RhoH, have been identified in PIDs. However, several other Rho small G proteins might also contribute to the deregulation and phenotype observed in PIDs. Their contribution in PIDs may involve their main regulator, Rho guanine nucleotide exchange factors such as DOCK2 and DOCK8, wherein mutations may result in the impairment of small Rho GTPase activation. Thus, this review outlines the potential contribution of several small Rho GTPases to the promotion of PIDs.
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Affiliation(s)
- Ilie Fadzilah Hashim
- Primary Immunodeficiency Diseases Group, Regenerative Medicine Cluster, Advanced Medical and Dental Institute, Universiti Sains Malaysia, Kepala Batas, Penang, 13200, Malaysia.
| | - Ana Masara Ahmad Mokhtar
- Bioprocess Technology Division, School of Industrial Technology, Universiti Sains Malaysia, Gelugor, Penang, 11800, Malaysia.
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17
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Bonavita R, Laukkanen MO. Common Signal Transduction Molecules Activated by Bacterial Entry into a Host Cell and by Reactive Oxygen Species. Antioxid Redox Signal 2021; 34:486-503. [PMID: 32600071 DOI: 10.1089/ars.2019.7968] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Significance: An increasing number of pathogens are acquiring resistance to antibiotics. Efficient antimicrobial drug regimens are important even for the most advanced therapies, which range from cutting-edge invasive clinical protocols, such as robotic surgeries, to the treatment of harmless bacterial diseases and to minor scratches to the skin. Therefore, there is an urgent need to survey alternative antimicrobial drugs that can reinforce or replace existing antibiotics. Recent Advances: Bacterial proteins that are critical for energy metabolism, promising novel anticancer thiourea derivatives, and the use of synthetic molecules that increase the sensitivity of currently used antibiotics are among the recently discovered antimicrobial drugs. Critical Issues: In the development of new drugs, serious consideration should be given to the previous bacterial evolutionary selection caused by antibiotics, by the high proliferation rate of bacteria, and by the simple prokaryotic structure of bacteria. Future Directions: The survey of drug targets has mainly focused on bacterial proteins, although host signaling molecules involved in the treatment of various pathologies may have unknown antimicrobial characteristics. Recent data have suggested that small molecule inhibitors might enhance the effect of antibiotics, for example, by limiting bacterial entry into host cells. Phagocytosis, the mechanism by which host cells internalize pathogens through β-actin cytoskeletal rearrangement, induces calcium signaling, small GTPase activation, and phosphorylation of the phosphatidylinositol 3-kinase-serine/threonine-specific protein kinase B pathway. Antioxid. Redox Signal. 34, 486-503.
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Affiliation(s)
- Raffaella Bonavita
- Experimental Institute of Endocrinology and Oncology G. Salvatore, IEOS CNR, Naples, Italy
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18
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Lv Z, de-Carvalho J, Telley IA, Großhans J. Cytoskeletal mechanics and dynamics in the Drosophila syncytial embryo. J Cell Sci 2021; 134:134/4/jcs246496. [PMID: 33597155 DOI: 10.1242/jcs.246496] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Cell and tissue functions rely on the genetic programmes and cascades of biochemical signals. It has become evident during the past decade that the physical properties of soft material that govern the mechanics of cells and tissues play an important role in cellular function and morphology. The biophysical properties of cells and tissues are determined by the cytoskeleton, consisting of dynamic networks of F-actin and microtubules, molecular motors, crosslinkers and other associated proteins, among other factors such as cell-cell interactions. The Drosophila syncytial embryo represents a simple pseudo-tissue, with its nuclei orderly embedded in a structured cytoskeletal matrix at the embryonic cortex with no physical separation by cellular membranes. Here, we review the stereotypic dynamics and regulation of the cytoskeleton in Drosophila syncytial embryos and how cytoskeletal dynamics underlies biophysical properties and the emergence of collective features. We highlight the specific features and processes of syncytial embryos and discuss the applicability of biophysical approaches.
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Affiliation(s)
- Zhiyi Lv
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, 266003, China
| | - Jorge de-Carvalho
- Instituto Gulbenkian de Ciência, Fundação Calouste Gulbenkian, 2780-156 Oeiras, Portugal
| | - Ivo A Telley
- Instituto Gulbenkian de Ciência, Fundação Calouste Gulbenkian, 2780-156 Oeiras, Portugal
| | - Jörg Großhans
- Fachbereich Biologie, Philipps-Universität Marburg, 35043 Marburg, Germany
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19
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Chang L, Yang J, Jo CH, Boland A, Zhang Z, McLaughlin SH, Abu-Thuraia A, Killoran RC, Smith MJ, Côté JF, Barford D. Structure of the DOCK2-ELMO1 complex provides insights into regulation of the auto-inhibited state. Nat Commun 2020; 11:3464. [PMID: 32651375 PMCID: PMC7351999 DOI: 10.1038/s41467-020-17271-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 06/17/2020] [Indexed: 12/29/2022] Open
Abstract
DOCK (dedicator of cytokinesis) proteins are multidomain guanine nucleotide exchange factors (GEFs) for RHO GTPases that regulate intracellular actin dynamics. DOCK proteins share catalytic (DOCKDHR2) and membrane-associated (DOCKDHR1) domains. The structurally-related DOCK1 and DOCK2 GEFs are specific for RAC, and require ELMO (engulfment and cell motility) proteins for function. The N-terminal RAS-binding domain (RBD) of ELMO (ELMORBD) interacts with RHOG to modulate DOCK1/2 activity. Here, we determine the cryo-EM structures of DOCK2-ELMO1 alone, and as a ternary complex with RAC1, together with the crystal structure of a RHOG-ELMO2RBD complex. The binary DOCK2-ELMO1 complex adopts a closed, auto-inhibited conformation. Relief of auto-inhibition to an active, open state, due to a conformational change of the ELMO1 subunit, exposes binding sites for RAC1 on DOCK2DHR2, and RHOG and BAI GPCRs on ELMO1. Our structure explains how up-stream effectors, including DOCK2 and ELMO1 phosphorylation, destabilise the auto-inhibited state to promote an active GEF.
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Affiliation(s)
- Leifu Chang
- MRC Laboratory of Molecular Biology, Cambridge, CB2 0QH, UK
- Department of Biological Sciences, Purdue University, West Lafayette, IN, 47907, USA
| | - Jing Yang
- MRC Laboratory of Molecular Biology, Cambridge, CB2 0QH, UK
| | - Chang Hwa Jo
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Québec, H3T 1J4, Canada
| | - Andreas Boland
- MRC Laboratory of Molecular Biology, Cambridge, CB2 0QH, UK
- Department of Molecular Biology, Science III, University of Geneva, Geneva, Switzerland
| | - Ziguo Zhang
- MRC Laboratory of Molecular Biology, Cambridge, CB2 0QH, UK
| | | | - Afnan Abu-Thuraia
- Montreal Institute of Clinical Research (IRCM), Montréal, QC, H2W 1R7, Canada
| | - Ryan C Killoran
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Québec, H3T 1J4, Canada
| | - Matthew J Smith
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Québec, H3T 1J4, Canada
- Department of Pathology and Cell Biology, Faculty of Medicine, Université de Montréal, Montréal, QC, H3T 1J4, Canada
| | - Jean-Francois Côté
- Montreal Institute of Clinical Research (IRCM), Montréal, QC, H2W 1R7, Canada
- Department of Biochemistry and Molecular Medicine, Faculty of Medicine, Université de Montréal, Montréal, QC, H3C 3J7, Canada
- Department of Anatomy and Cell Biology, McGill University, Montréal, QC, H3A 0C7, Canada
| | - David Barford
- MRC Laboratory of Molecular Biology, Cambridge, CB2 0QH, UK.
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20
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Turn RE, East MP, Prekeris R, Kahn RA. The ARF GAP ELMOD2 acts with different GTPases to regulate centrosomal microtubule nucleation and cytokinesis. Mol Biol Cell 2020; 31:2070-2091. [PMID: 32614697 PMCID: PMC7543072 DOI: 10.1091/mbc.e20-01-0012] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
ELMOD2 is a ∼32 kDa protein first purified by its GTPase-activating protein (GAP) activity toward ARL2 and later shown to have uniquely broad specificity toward ARF family GTPases in in vitro assays. To begin the task of defining its functions in cells, we deleted ELMOD2 in immortalized mouse embryonic fibroblasts and discovered a number of cellular defects, which are reversed upon expression of ELMOD2-myc. We show that these defects, resulting from the loss of ELMOD2, are linked to two different pathways and two different GTPases: with ARL2 and TBCD to support microtubule nucleation from centrosomes and with ARF6 in cytokinesis. These data highlight key aspects of signaling by ARF family GAPs that contribute to previously underappreciated sources of complexity, including GAPs acting from multiple sites in cells, working with multiple GTPases, and contributing to the spatial and temporal control of regulatory GTPases by serving as both GAPs and effectors.
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Affiliation(s)
- Rachel E Turn
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322.,Biochemistry, Cell & Developmental Biology Graduate Program, Laney Graduate School, Emory University, Atlanta, GA 30307
| | - Michael P East
- Department of Pharmacology, University of North Carolina Chapel Hill, Chapel Hill, NC 27599
| | - Rytis Prekeris
- Department of Cell and Developmental Biology, University of Colorado, Aurora, CO 80045
| | - Richard A Kahn
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322
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21
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Mikdache A, Fontenas L, Albadri S, Revenu C, Loisel-Duwattez J, Lesport E, Degerny C, Del Bene F, Tawk M. Elmo1 function, linked to Rac1 activity, regulates peripheral neuronal numbers and myelination in zebrafish. Cell Mol Life Sci 2020; 77:161-177. [PMID: 31161284 PMCID: PMC11104998 DOI: 10.1007/s00018-019-03167-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 05/28/2019] [Accepted: 05/28/2019] [Indexed: 12/20/2022]
Abstract
Peripheral nervous system development involves a tight coordination of neuronal birth and death and a substantial remodelling of the myelinating glia cytoskeleton to achieve myelin wrapping of its projecting axons. However, how these processes are coordinated through time is still not understood. We have identified engulfment and cell motility 1, Elmo1, as a novel component that regulates (i) neuronal numbers within the Posterior Lateral Line ganglion and (ii) radial sorting of axons by Schwann cells (SC) and myelination in the PLL system in zebrafish. Our results show that neuronal and myelination defects observed in elmo1 mutant are rescued through small GTPase Rac1 activation. Inhibiting macrophage development leads to a decrease in neuronal numbers, while peripheral myelination is intact. However, elmo1 mutants do not show defective macrophage activity, suggesting a role for Elmo1 in PLLg neuronal development and SC myelination independent of macrophages. Forcing early Elmo1 and Rac1 expression specifically within SCs rescues elmo1-/- myelination defects, highlighting an autonomous role for Elmo1 and Rac1 in radial sorting of axons by SCs and myelination. This uncovers a previously unknown function of Elmo1 that regulates fundamental aspects of PNS development.
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Affiliation(s)
- Aya Mikdache
- U1195, Inserm, University Paris Sud, University Paris-Saclay, 94276, Le Kremlin Bicêtre, France
| | - Laura Fontenas
- U1195, Inserm, University Paris Sud, University Paris-Saclay, 94276, Le Kremlin Bicêtre, France
- Department of Biology, University of Virginia, Charlottesville, VA, 22904-4328, USA
| | - Shahad Albadri
- Institut Curie, PSL Research University, 75005, Paris, France
| | - Celine Revenu
- Institut Curie, PSL Research University, 75005, Paris, France
| | - Julien Loisel-Duwattez
- U1195, Inserm, University Paris Sud, University Paris-Saclay, 94276, Le Kremlin Bicêtre, France
| | - Emilie Lesport
- U1195, Inserm, University Paris Sud, University Paris-Saclay, 94276, Le Kremlin Bicêtre, France
| | - Cindy Degerny
- U1195, Inserm, University Paris Sud, University Paris-Saclay, 94276, Le Kremlin Bicêtre, France
| | | | - Marcel Tawk
- U1195, Inserm, University Paris Sud, University Paris-Saclay, 94276, Le Kremlin Bicêtre, France.
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22
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Structural Insights into the Regulation Mechanism of Small GTPases by GEFs. Molecules 2019; 24:molecules24183308. [PMID: 31514408 PMCID: PMC6767298 DOI: 10.3390/molecules24183308] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 09/09/2019] [Accepted: 09/10/2019] [Indexed: 12/12/2022] Open
Abstract
Small GTPases are key regulators of cellular events, and their dysfunction causes many types of cancer. They serve as molecular switches by cycling between inactive guanosine diphosphate (GDP)-bound and active guanosine triphosphate (GTP)-bound states. GTPases are deactivated by GTPase-activating proteins (GAPs) and are activated by guanine-nucleotide exchange factors (GEFs). The intrinsic GTP hydrolysis activity of small GTPases is generally low and is accelerated by GAPs. GEFs promote GDP dissociation from small GTPases to allow for GTP binding, which results in a conformational change of two highly flexible segments, called switch I and switch II, that enables binding of the gamma phosphate and allows small GTPases to interact with downstream effectors. For several decades, crystal structures of many GEFs and GAPs have been reported and have shown tremendous structural diversity. In this review, we focus on the latest structural studies of GEFs. Detailed pictures of the variety of GEF mechanisms at atomic resolution can provide insights into new approaches for drug discovery.
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Silencing ELMO3 Inhibits the Growth, Invasion, and Metastasis of Gastric Cancer. BIOMED RESEARCH INTERNATIONAL 2018; 2018:3764032. [PMID: 30345300 PMCID: PMC6174816 DOI: 10.1155/2018/3764032] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Accepted: 09/03/2018] [Indexed: 12/19/2022]
Abstract
ELMO3 is a member of the engulfment and cell motility (ELMO) protein family, which plays a vital role in the process of chemotaxis and metastasis of tumor cells. However, remarkably little is known about the role of ELMO3 in cancer. The present study was conducted to investigate the function and role of ELMO3 in gastric cancer (GC) progression. The expression level of ELMO3 in gastric cancer tissues and cell lines was measured by means of real-time quantitative PCR (qPCR) and Western blot analysis. RNA interference was used to inhibit ELMO3 expression in gastric cancer cells. Then, wound-healing assays, Transwell assays, MTS assays, flow cytometry, and fluorescence microscopy were applied to detect cancer cell migration, cell invasion, cell proliferation, the cell cycle, and F-actin polymerization, respectively. The results revealed that ELMO3 expression in GC tumor tissues was significantly higher than in the paired adjacent tissues. Moreover, knockdown of ELMO3 by a specific siRNA significantly inhibited the processes of cell proliferation, invasion, metastasis, regulation of the cell cycle, and F-actin polymerization. Collectively, the results indicate that ELMO3 participates in the processes of cell growth, invasion, and migration, and ELMO3 is expected to be a potential diagnostic and prognostic marker for GC.
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Kjos I, Vestre K, Guadagno NA, Borg Distefano M, Progida C. Rab and Arf proteins at the crossroad between membrane transport and cytoskeleton dynamics. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2018; 1865:1397-1409. [PMID: 30021127 DOI: 10.1016/j.bbamcr.2018.07.009] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Revised: 07/05/2018] [Accepted: 07/13/2018] [Indexed: 01/04/2023]
Abstract
The intracellular movement and positioning of organelles and vesicles is mediated by the cytoskeleton and molecular motors. Small GTPases like Rab and Arf proteins are main regulators of intracellular transport by connecting membranes to cytoskeleton motors or adaptors. However, it is becoming clear that interactions between these small GTPases and the cytoskeleton are important not only for the regulation of membrane transport. In this review, we will cover our current understanding of the mechanisms underlying the connection between Rab and Arf GTPases and the cytoskeleton, with special emphasis on the double role of these interactions, not only in membrane trafficking but also in membrane and cytoskeleton remodeling. Furthermore, we will highlight the most recent findings about the fine control mechanisms of crosstalk between different members of Rab, Arf, and Rho families of small GTPases in the regulation of cytoskeleton organization.
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Affiliation(s)
- Ingrid Kjos
- Department of Biosciences, University of Oslo, Norway
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25
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Programmed Cell Death During Caenorhabditis elegans Development. Genetics 2017; 203:1533-62. [PMID: 27516615 DOI: 10.1534/genetics.115.186247] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Accepted: 04/22/2016] [Indexed: 12/21/2022] Open
Abstract
Programmed cell death is an integral component of Caenorhabditis elegans development. Genetic and reverse genetic studies in C. elegans have led to the identification of many genes and conserved cell death pathways that are important for the specification of which cells should live or die, the activation of the suicide program, and the dismantling and removal of dying cells. Molecular, cell biological, and biochemical studies have revealed the underlying mechanisms that control these three phases of programmed cell death. In particular, the interplay of transcriptional regulatory cascades and networks involving multiple transcriptional regulators is crucial in activating the expression of the key death-inducing gene egl-1 and, in some cases, the ced-3 gene in cells destined to die. A protein interaction cascade involving EGL-1, CED-9, CED-4, and CED-3 results in the activation of the key cell death protease CED-3, which is tightly controlled by multiple positive and negative regulators. The activation of the CED-3 caspase then initiates the cell disassembly process by cleaving and activating or inactivating crucial CED-3 substrates; leading to activation of multiple cell death execution events, including nuclear DNA fragmentation, mitochondrial elimination, phosphatidylserine externalization, inactivation of survival signals, and clearance of apoptotic cells. Further studies of programmed cell death in C. elegans will continue to advance our understanding of how programmed cell death is regulated, activated, and executed in general.
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Morishita K, Anh Suong DN, Yoshida H, Yamaguchi M. The Drosophila DOCK family protein Sponge is required for development of the air sac primordium. Exp Cell Res 2017; 354:95-102. [PMID: 28341448 DOI: 10.1016/j.yexcr.2017.03.044] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2016] [Revised: 03/18/2017] [Accepted: 03/20/2017] [Indexed: 12/14/2022]
Abstract
Dedicator of cytokinesis (DOCK) family genes are known as DOCK1-DOCK11 in mammals. DOCK family proteins mainly regulate actin filament polymerization and/or depolymerization and are GEF proteins, which contribute to cellular signaling events by activating small G proteins. Sponge (Spg) is a Drosophila counterpart to mammalian DOCK3/DOCK4, and plays a role in embryonic central nervous system development, R7 photoreceptor cell differentiation, and adult thorax development. In order to conduct further functional analyses on Spg in vivo, we examined its localization in third instar larval wing imaginal discs. Immunostaining with purified anti-Spg IgG revealed that Spg mainly localized in the air sac primordium (ASP) in wing imaginal discs. Spg is therefore predicted to play an important role in the ASP. The specific knockdown of Spg by the breathless-GAL4 driver in tracheal cells induced lethality accompanied with a defect in ASP development and the induction of apoptosis. The monitoring of ERK signaling activity in wing imaginal discs by immunostaining with anti-diphospho-ERK IgG revealed reductions in the ERK signal cascade in Spg knockdown clones. Furthermore, the overexpression of D-raf suppressed defects in survival and the proliferation of cells in the ASP induced by the knockdown of Spg. Collectively, these results indicate that Spg plays a critical role in ASP development and tracheal cell viability that is mediated by the ERK signaling pathway.
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Affiliation(s)
- Kazushge Morishita
- Department of Applied Biology, The Center for Advanced Insect Research, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Dang Ngoc Anh Suong
- Department of Applied Biology, The Center for Advanced Insect Research, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Hideki Yoshida
- Department of Applied Biology, The Center for Advanced Insect Research, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Masamitsu Yamaguchi
- Department of Applied Biology, The Center for Advanced Insect Research, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan.
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27
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Vitali T, Girald-Berlingeri S, Randazzo PA, Chen PW. Arf GAPs: A family of proteins with disparate functions that converge on a common structure, the integrin adhesion complex. Small GTPases 2017; 10:280-288. [PMID: 28362242 DOI: 10.1080/21541248.2017.1299271] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
ADP-ribosylation factors (Arfs) are members of the Ras GTPase superfamily. The function of Arfs is dependent on GTPase-activating proteins (GAPs) and guanine nucleotide exchange factors (GEFs), which allow Arfs to cycle between the GDP-bound and GTP-bound forms. Arf GAPs have been shown to be present in integrin adhesion complexes, which include focal adhesions. Integrin adhesion complexes are composed of integrins, scaffolding proteins and signaling proteins and regulate cell proliferation, survival, differentiation and migration. Understanding the role of Arf GAPs in the regulation of integrin adhesion complexes is relevant to understanding normal physiology and cancer. In this review, we will discuss the contribution of the Arf GAP family members to the regulation of integrin adhesion complexes, examining the diverse mechanisms by which they control integrin adhesion complex formation, maturation and dissolution. GIT1 and ARAP2 serve as GAPs for Arf6, regulating Rac1 and other effectors by mechanisms still being defined. In contrast, GIT2 regulates Rac1 independent of Arf6. AGAP2 binds to and regulates focal adhesion kinase (FAK). ARAP2 and ACAP1, both Arf6 GAPs, regulate membrane trafficking of integrins through different endocytic pathways, exerting opposite effects on focal adhesions. ASAP1 not only regulates actin cytoskeleton remodeling through its interaction with nonmuscle myosin 2A, but is also important in integrin recycling. These examples illustrate the diversity and versatility of Arf GAPs as regulators of integrin adhesion complex structure and function.
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Affiliation(s)
- Teresa Vitali
- a Laboratory of Cell and Molecular Biology , National Cancer Institute, National Institutes of Health , Bethesda , MD , USA
| | - Sofia Girald-Berlingeri
- a Laboratory of Cell and Molecular Biology , National Cancer Institute, National Institutes of Health , Bethesda , MD , USA
| | - Paul A Randazzo
- a Laboratory of Cell and Molecular Biology , National Cancer Institute, National Institutes of Health , Bethesda , MD , USA
| | - Pei-Wen Chen
- b Department of Biology , Williams College , Williamstown , MA , USA
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28
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Penberthy KK, Ravichandran KS. Apoptotic cell recognition receptors and scavenger receptors. Immunol Rev 2016; 269:44-59. [PMID: 26683144 DOI: 10.1111/imr.12376] [Citation(s) in RCA: 134] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Phosphatidylserine recognition receptors are a highly diverse set of receptors grouped by their ability to recognize the 'eat-me' signal phosphatidylserine on apoptotic cells. Most of the phosphatidylserine recognition receptors dampen inflammation by inducing the production of anti-inflammatory mediators during the phagocytosis of apoptotic corpses. However, many phosphatidylserine receptors are also capable of recognizing other ligands, with some receptors being categorized as scavenger receptors. It is now appreciated that these receptors can elicit different downstream events for particular ligands. Therefore, how phosphatidylserine recognition receptors mediate specific signals during recognition of apoptotic cells versus other ligands, and how this might help regulate the inflammatory state of a tissue is an important question that is not fully understood. Here, we revisit the work on signaling downstream of the phosphatidylserine recognition receptor BAI1, and evaluate how these and other signaling modules mediate signaling downstream from other receptors, including Stabilin-2, MerTK, and αvβ5. We also propose the concept that phosphatidylserine recognition receptors could be viewed as a subset of scavenger receptors that are capable of eliciting anti-inflammatory responses to apoptotic cells.
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Affiliation(s)
- Kristen K Penberthy
- Department of Microbiology, Immunology, and Cancer Biology, Center for Cell Clearance, University of Virginia, Charlottesville, VA, USA
| | - Kodi S Ravichandran
- Department of Microbiology, Immunology, and Cancer Biology, Center for Cell Clearance, University of Virginia, Charlottesville, VA, USA
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29
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Koubek EJ, Santy LC. ARF1 and ARF6 regulate recycling of GRASP/Tamalin and the Rac1-GEF Dock180 during HGF-induced Rac1 activation. Small GTPases 2016; 9:242-259. [PMID: 27562622 DOI: 10.1080/21541248.2016.1219186] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Hepatocyte growth factor (HGF) is a potent signaling factor that acts on epithelial cells, causing them to dissociate and scatter. This migration is coordinated by a number of small GTPases, such as ARF6 and Rac1. Active ARF6 is required for HGF-stimulated migration and intracellular levels of ARF6-GTP and Rac1-GTP increase following HGF treatment. During migration, cross talk between ARF6 and Rac1 occurs through formation of a multi-protein complex containing the ARF-GEF cytohesin-2, the scaffolding protein GRASP/Tamalin, and the Rac1-GEF Dock180. Previously, the role of ARF6 in this process was unclear. We have now found that ARF6 and ARF1 regulate trafficking of GRASP and Dock180 to the plasma membrane following HGF treatment. Trafficking of GRASP and Dock180 is impaired by blocking ARF6-mediated recycling pathways and is required for HGF-stimulated Rac1 activation. Finally, HGF treatment stimulates association of GRASP and Dock180. Inhibition of ARF6 trafficking pathways traps GRASP and Dock180 as a complex in the cell.
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Affiliation(s)
- Emily J Koubek
- a Department of Biochemistry and Molecular Biology , The Pennsylvania State University , University Park , PA , USA
| | - Lorraine C Santy
- a Department of Biochemistry and Molecular Biology , The Pennsylvania State University , University Park , PA , USA
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30
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Wang Y, Xu X, Pan M, Jin T. ELMO1 Directly Interacts with Gβγ Subunit to Transduce GPCR Signaling to Rac1 Activation in Chemotaxis. J Cancer 2016; 7:973-83. [PMID: 27313788 PMCID: PMC4910590 DOI: 10.7150/jca.15118] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Accepted: 03/14/2016] [Indexed: 01/13/2023] Open
Abstract
Diverse chemokines bind to G protein-coupled receptors (GPCRs) to activate the small GTPase Rac to regulate F-actin dynamics during chemotaxis. ELMO and Dock proteins form complexes that function as guanine nucleotide exchange factors (GEFs) for Rac activation. However, the linkage between GPCR activation and the ELMO/Dock-mediated Rac activation is not fully understood. In the present study, we show that chemoattractants induce dynamic membrane translocation of ELMO1 in mammalian cells. ELMO1 plays an important role in GPCR-mediated chemotaxis. We also reveal that ELMO1 and Dock1 form a stable complex. Importantly, activation of chemokine GPCR promotes the interaction between ELMO1 and Gβγ. The ELMO1-Gβγ interaction is through the N-terminus of ELMO1 protein and is important for the membrane translocation of ELMO1. ELMO1 is required for Rac1 activation upon chemoattractant stimulation. Our results suggest that chemokine GPCR-mediated interaction between Gβγ and ELMO1/Dock1 complex might serve as an evolutionarily conserved mechanism for Rac activation to regulate actin cytoskeleton for chemotaxis of human cells.
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Affiliation(s)
- Youhong Wang
- Chemotaxis Signaling Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health; Rockville, MD 20852, USA
| | - Xuehua Xu
- Chemotaxis Signaling Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health; Rockville, MD 20852, USA
| | - Miao Pan
- Chemotaxis Signaling Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health; Rockville, MD 20852, USA
| | - Tian Jin
- Chemotaxis Signaling Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health; Rockville, MD 20852, USA
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Abstract
Phagocytosis is defined as a cellular uptake pathway for particles of greater than 0.5 μm in diameter. Particle clearance by phagocytosis is of critical importance for tissue health and homeostasis. The ultimate goal of anti-pathogen phagocytosis is to destroy engulfed bacteria or fungi and to stimulate cell-cell signaling that mount an efficient immune defense. In contrast, clearance phagocytosis of apoptotic cells and cell debris is anti-inflammatory. High capacity clearance phagocytosis pathways are available to professional phagocytes of the immune system and the retina. Additionally, a low capacity, so-called bystander phagocytic pathway is available to most other cell types. Different phagocytic pathways are stimulated by particle ligation of distinct surface receptors but all forms of phagocytosis require F-actin recruitment beneath tethered particles and F-actin re-arrangement promoting engulfment, which are controlled by Rho family GTPases. The specificity of Rho GTPase activity during the different forms of phagocytosis by mammalian cells is the subject of this review.
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Affiliation(s)
- Yingyu Mao
- a Department of Biological Sciences; Center for Cancer, Genetic Diseases, and Gene Regulation; Fordham University ; Bronx , NY , USA
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32
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Sun Y, Ren W, Côté JF, Hinds PW, Hu X, Du K. ClipR-59 interacts with Elmo2 and modulates myoblast fusion. J Biol Chem 2015; 290:6130-40. [PMID: 25572395 PMCID: PMC4358253 DOI: 10.1074/jbc.m114.616680] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Revised: 01/06/2015] [Indexed: 11/06/2022] Open
Abstract
Recent studies using ClipR-59 knock-out mice implicated this protein in the regulation of muscle function. In this report, we have examined the role of ClipR-59 in muscle differentiation and found that ClipR-59 knockdown in C2C12 cells suppressed myoblast fusion. To elucidate the molecular mechanism whereby ClipR-59 regulates myoblast fusion, we carried out a yeast two-hybrid screen using ClipR-59 as the bait and identified Elmo2, a member of the Engulfment and cell motility protein family, as a novel ClipR-59-associated protein. We showed that the interaction between ClipR-59 and Elmo2 was mediated by the atypical PH domain of Elmo2 and the Glu-Pro-rich domain of ClipR-59 and regulated by Rho-GTPase. We have examined the impact of ClipR-59 on Elmo2 downstream signaling and found that interaction of ClipR-59 with Elmo2 enhanced Rac1 activation. Collectively, our studies demonstrate that formation of an Elmo2·ClipR-59 complex plays an important role in myoblast fusion.
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Affiliation(s)
- Yingmin Sun
- From the State Key Laboratory for Agro-biotechnology, College of Biological Science, China Agricultural University, 10083 Beijing, China, the Molecular Oncology Research Institute, Tufts Medical Center, Boston, Massachusetts 02111, and
| | - Wenying Ren
- the Molecular Oncology Research Institute, Tufts Medical Center, Boston, Massachusetts 02111, and
| | - Jean-François Côté
- the Institut de Recherches Cliniques de Montréal, Montréal, Université de Montréal, Québec H2W 1R7, Canada
| | - Philip W Hinds
- the Molecular Oncology Research Institute, Tufts Medical Center, Boston, Massachusetts 02111, and
| | - Xiaoxiang Hu
- From the State Key Laboratory for Agro-biotechnology, College of Biological Science, China Agricultural University, 10083 Beijing, China
| | - Keyong Du
- the Molecular Oncology Research Institute, Tufts Medical Center, Boston, Massachusetts 02111, and
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Awad R, Sévajol M, Ayala I, Chouquet A, Frachet P, Gans P, Reiser JB, Kleman JP. The SH3 regulatory domain of the hematopoietic cell kinase Hck binds ELMO via its polyproline motif. FEBS Open Bio 2015; 5:99-106. [PMID: 25737835 PMCID: PMC4338372 DOI: 10.1016/j.fob.2015.01.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Revised: 01/23/2015] [Accepted: 01/30/2015] [Indexed: 12/27/2022] Open
Abstract
Eukaryotic EnguLfment and cell MOtility (ELMO) proteins form an evolutionary conserved family of regulators involved in small GTPase dependent actin remodeling processes that regulates the guanine exchange factor activity of some of the Downstream Of CrK (DOCK) family members. Gathered data strongly suggest that DOCK activation by ELMO and the subsequent signaling result from a subtle balance in the binding of partners to ELMO. Among its putative upward modulators, the Hematopoietic cell kinase (Hck), a member of the Src kinase superfamily, has been identified as a binding partner and a specific tyrosine kinase for ELMO1. Indeed, Hck is implicated in distinct molecular signaling pathways governing phagocytosis, cell adhesion, and migration of hematopoietic cells. Although ELMO1 has been shown to interact with the regulatory Src Homology 3 (SH3) domain of Hck, no direct evidence indicating the mode of interaction between Hck and ELMO1 have been provided in the literature. In the present study, we report convergent pieces of evidence that demonstrate the specific interaction between the SH3 domain of Hck and the polyproline motif of ELMO1. Our results also suggest that the tyrosine-phosphorylation state of ELMO1 tail might act as a putative modulator of Hck kinase activity towards ELMO1 that in turn participates in DOCK180 activation and further triggers subsequent signaling towards actin remodeling.
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Key Words
- DOCK, Downstream Of CrK protein family
- EAD, ELMO Autoregulatory Domain
- EID, ELMO Inhibitory Domain
- ELMO
- ELMO, EnguLfment and cell MOtility protein family
- ERM, Ezrin–Radixin–Moesin protein family
- FRET, Förster (Fluorescence) resonance energy transfer
- GEF, Guanine nucleotide Exchange Factor
- GSH, Glutathione (reduced)
- GST, Glutathione S-Transferase
- Hck
- Hck, Hematopoietic cell kinase
- PH, Pleckstrin Homology domain
- Phagocytosis
- Phosphorylation
- Polyproline
- PxP, Polyproline motif
- RBD, Rho-Binding Domain
- SH3
- SH3, Src Homology 3 domain
- TAMs, Tyro3, Axl and Mer receptor tyrosine kinase family
- TEV, Tobacco Etch Virus
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Affiliation(s)
- Rida Awad
- Univ. Grenoble Alpes, IBS, F-38044 Grenoble, France
| | | | - Isabel Ayala
- Univ. Grenoble Alpes, IBS, F-38044 Grenoble, France
| | | | | | - Pierre Gans
- Univ. Grenoble Alpes, IBS, F-38044 Grenoble, France
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Schäker K, Bartsch S, Patry C, Stoll SJ, Hillebrands JL, Wieland T, Kroll J. The bipartite rac1 Guanine nucleotide exchange factor engulfment and cell motility 1/dedicator of cytokinesis 180 (elmo1/dock180) protects endothelial cells from apoptosis in blood vessel development. J Biol Chem 2015; 290:6408-18. [PMID: 25586182 DOI: 10.1074/jbc.m114.633701] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Engulfment and cell motility 1/dedicator of cytokinesis 180 (Elmo1/Dock180) is a bipartite guanine nucleotide exchange factor for the monomeric GTPase Ras-related C3 botulinum toxin substrate 1 (Rac1). Elmo1/Dock180 regulates Rac1 activity in a specific spatiotemporal manner in endothelial cells (ECs) during zebrafish development and acts downstream of the Netrin-1/Unc5-homolog B (Unc5B) signaling cascade. However, mechanistic details on the pathways by which Elmo1/Dock180 regulates endothelial function and vascular development remained elusive. In this study, we aimed to analyze the vascular function of Elmo1 and Dock180 in human ECs and during vascular development in zebrafish embryos. In vitro overexpression of Elmo1 and Dock180 in ECs reduced caspase-3/7 activity and annexin V-positive cell number upon induction of apoptosis. This protective effect of Elmo1 and Dock180 is mediated by activation of Rac1, p21-activated kinase (PAK) and AKT/protein kinase B (AKT) signaling. In zebrafish, Elmo1 and Dock180 overexpression reduced the total apoptotic cell and apoptotic EC number and promoted the formation of blood vessels during embryogenesis. In conclusion, Elmo1 and Dock180 protect ECs from apoptosis by the activation of the Rac1/PAK/AKT signaling cascade in vitro and in vivo. Thus, Elmo1 and Dock180 facilitate blood vessel formation by stabilization of the endothelium during angiogenesis.
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Affiliation(s)
- Kathrin Schäker
- From the Department of Vascular Biology and Tumor Angiogenesis, Center for Biomedicine and Medical Technology Mannheim (CBTM) and Division of Vascular Oncology and Metastasis, German Cancer Research Center (DKFZ-ZMBH Alliance), 69120 Heidelberg, Germany, and
| | - Susanne Bartsch
- From the Department of Vascular Biology and Tumor Angiogenesis, Center for Biomedicine and Medical Technology Mannheim (CBTM) and
| | - Christian Patry
- From the Department of Vascular Biology and Tumor Angiogenesis, Center for Biomedicine and Medical Technology Mannheim (CBTM) and
| | - Sandra J Stoll
- From the Department of Vascular Biology and Tumor Angiogenesis, Center for Biomedicine and Medical Technology Mannheim (CBTM) and
| | - Jan-Luuk Hillebrands
- Department of Pathology and Medical Biology, Division of Pathology, University Medical Center Groningen, 9700 RB Groningen, The Netherlands
| | - Thomas Wieland
- Institute of Experimental and Clinical Pharmacology and Toxicology, Medical Faculty Mannheim of Heidelberg University, 68167 Mannheim, Germany
| | - Jens Kroll
- From the Department of Vascular Biology and Tumor Angiogenesis, Center for Biomedicine and Medical Technology Mannheim (CBTM) and Division of Vascular Oncology and Metastasis, German Cancer Research Center (DKFZ-ZMBH Alliance), 69120 Heidelberg, Germany, and
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35
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Goicoechea SM, Awadia S, Garcia-Mata R. I'm coming to GEF you: Regulation of RhoGEFs during cell migration. Cell Adh Migr 2014; 8:535-49. [PMID: 25482524 PMCID: PMC4594598 DOI: 10.4161/cam.28721] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Cell migration is a highly regulated multistep process that requires the coordinated regulation of cell adhesion, protrusion, and contraction. These processes require numerous protein–protein interactions and the activation of specific signaling pathways. The Rho family of GTPases plays a key role in virtually every aspect of the cell migration cycle. The activation of Rho GTPases is mediated by a large and diverse family of proteins; the guanine nucleotide exchange factors (RhoGEFs). GEFs work immediately upstream of Rho proteins to provide a direct link between Rho activation and cell–surface receptors for various cytokines, growth factors, adhesion molecules, and G protein-coupled receptors. The regulated targeting and activation of RhoGEFs is essential to coordinate the migratory process. In this review, we summarize the recent advances in our understanding of the role of RhoGEFs in the regulation of cell migration.
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Key Words
- DH, Dbl-homology
- DHR, DOCK homology region
- DOCK, dedicator of cytokinesis
- ECM, extracellular matrix
- EGF, epidermal growth factor
- FA, focal adhesion
- FN, fibronectin
- GAP, GTPase activating protein
- GDI, guanine nucleotide dissociation inhibitor
- GEF, guanine nucleotide exchange factor
- GPCR, G protein-coupled receptor
- HGF, hepatocyte growth factor
- LPA, lysophosphatidic acid
- MII, myosin II
- PA, phosphatidic acid
- PDGF, platelet-derived growth factor
- PH, pleckstrin-homology
- PIP2, phosphatidylinositol 4, 5-bisphosphate
- PIP3, phosphatidylinositol (3, 4, 5)-trisphosphate.
- Rho GEFs
- Rho GTPases
- bFGF, basic fibroblast growth factor
- cell migration
- cell polarization
- focal adhesions
- guanine nucleotide exchange factors
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Affiliation(s)
- Silvia M Goicoechea
- a Department of Biological Sciences ; University of Toledo ; Toledo , OH USA
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Morishita K, Ozasa F, Eguchi K, Yoshioka Y, Yoshida H, Hiai H, Yamaguchi M. Drosophila DOCK family protein sponge regulates the JNK pathway during thorax development. Cell Struct Funct 2014; 39:113-24. [PMID: 25311449 DOI: 10.1247/csf.14008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The dedicator of cytokinesis (DOCK) family proteins that are conserved in a wide variety of species are known as DOCK1-DOCK11 in mammals. The Sponge (Spg) is a Drosophila counterpart to the mammalian DOCK3. Specific knockdown of spg by pannir-GAL4 or apterous-GAL4 driver in wing discs induced split thorax phenotype in adults. Reduction of the Drosophila c-Jun N-terminal kinase (JNK), basket (bsk) gene dose enhanced the spg knockdown-induced phenotype. Conversely, overexpression of bsk suppressed the split thorax phenotype. Monitoring JNK activity in the wing imaginal discs by immunostaining with anti-phosphorylated JNK (anti-pJNK) antibody together with examination of lacZ expression in a puckered-lacZ enhancer trap line revealed the strong reduction of the JNK activity in the spg knockdown clones. This was further confirmed by Western immunoblot analysis of extracts from wing discs of spg knockdown fly with anti-pJNK antibody. Furthermore, the Duolink in situ Proximity Ligation Assay method detected interaction signals between Spg and Rac1 in the wing discs. Taken together, these results indicate Spg positively regulates JNK pathway that is required for thorax development and the regulation is mediated by interaction with Rac1.
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37
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Kang PJ, Lee ME, Park HO. Bud3 activates Cdc42 to establish a proper growth site in budding yeast. ACTA ACUST UNITED AC 2014; 206:19-28. [PMID: 25002677 PMCID: PMC4085707 DOI: 10.1083/jcb.201402040] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Cell polarization occurs along a single axis that is generally determined by a spatial cue, yet the underlying mechanism is poorly understood. Using biochemical assays and live-cell imaging, we show that cell polarization to a proper growth site requires activation of Cdc42 by Bud3 in haploid budding yeast. Bud3 catalyzes the release of guanosine diphosphate (GDP) from Cdc42 and elevates intracellular Cdc42-guanosine triphosphate (GTP) levels in cells with inactive Cdc24, which has as of yet been the sole GDP-GTP exchange factor for Cdc42. Cdc42 is activated in two temporal steps in the G1 phase: the first depends on Bud3, whereas subsequent activation depends on Cdc24. Mutational analyses suggest that biphasic activation of Cdc42 in G1 is necessary for assembly of a proper bud site. Biphasic activation of Cdc42 or Rac GTPases may be a general mechanism for spatial cue-directed cell polarization in eukaryotes.
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Affiliation(s)
- Pil Jung Kang
- Department of Molecular Genetics and Molecular Cellular Developmental Biology Program, The Ohio State University, Columbus, OH 43210
| | - Mid Eum Lee
- Department of Molecular Genetics and Molecular Cellular Developmental Biology Program, The Ohio State University, Columbus, OH 43210
| | - Hay-Oak Park
- Department of Molecular Genetics and Molecular Cellular Developmental Biology Program, The Ohio State University, Columbus, OH 43210Department of Molecular Genetics and Molecular Cellular Developmental Biology Program, The Ohio State University, Columbus, OH 43210
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Gadea G, Blangy A. Dock-family exchange factors in cell migration and disease. Eur J Cell Biol 2014; 93:466-77. [PMID: 25022758 DOI: 10.1016/j.ejcb.2014.06.003] [Citation(s) in RCA: 147] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Revised: 06/10/2014] [Accepted: 06/17/2014] [Indexed: 02/06/2023] Open
Abstract
Dock family proteins are evolutionary conserved exchange factors for the Rho GTPases Rac and Cdc42. There are 11 Dock proteins in mammals, named Dock1 (or Dock180) to Dock11 that play different cellular functions. In particular, Dock proteins regulate actin cytoskeleton, cell adhesion and migration. Not surprisingly, members of the Dock family have been involved in various pathologies, including cancer and defects in the central nervous and immune systems. This review proposes an update of the recent findings regarding the function of Dock proteins, focusing on their role in the control of cell migration and invasion and the consequences in human diseases.
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Affiliation(s)
- Gilles Gadea
- CNRS UMR 5237, Centre de Recherche de Biochimie Macromoléculaire, France; Montpellier University, France
| | - Anne Blangy
- CNRS UMR 5237, Centre de Recherche de Biochimie Macromoléculaire, France; Montpellier University, France.
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Stevenson C, de la Rosa G, Anderson CS, Murphy PS, Capece T, Kim M, Elliott MR. Essential role of Elmo1 in Dock2-dependent lymphocyte migration. THE JOURNAL OF IMMUNOLOGY 2014; 192:6062-70. [PMID: 24821968 DOI: 10.4049/jimmunol.1303348] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Elmo1 and Elmo2 are highly homologous cytoplasmic adaptor proteins that interact with Dock family guanine nucleotide exchange factors to promote activation of the small GTPase Rac. In T lymphocytes, Dock2 is essential for CCR7- and CXCR4-dependent Rac activation and chemotaxis, but the role of Elmo proteins in regulating Dock2 function in primary T cells is not known. In this article, we show that endogenous Elmo1, but not Elmo2, interacts constitutively with Dock2 in mouse and human primary T cells. CD4(+) T cells from Elmo1(-/-) mice were profoundly impaired in polarization, Rac activation, and chemotaxis in response to CCR7 and CXCR4 stimulation. Transfection of full-length Elmo1, but not Elmo2 or a Dock2-binding mutant of Elmo1, rescued defective migration of Elmo1(-/-) T cells. Interestingly, Dock2 protein levels were reduced by 4-fold in Elmo1(-/-) lymphocytes despite normal levels of Dock2 mRNA. Dock2 polyubiquitination was increased in Elmo1(-/-) T cells, and treatment with proteasome inhibitors partially restored Dock2 levels in Elmo1(-/-) T cells. Finally, we show that Dock2 is directly ubiquitinated in CD4(+) T cells and that Elmo1 expression in heterologous cells inhibits ubiquitination of Dock2. Taken together, these findings reveal a previously unknown, nonredundant role for Elmo1 in controlling Dock2 levels and Dock2-dependent T cell migration in primary lymphocytes. Inhibition of Dock2 has therapeutic potential as a means to control recruitment of pathogenic lymphocytes in diseased tissues. This work provides valuable insights into the molecular regulation of Dock2 by Elmo1 that can be used to design improved inhibitors that target the Elmo-Dock-Rac signaling complex.
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Affiliation(s)
- Catherine Stevenson
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642; and David H. Smith Center for Vaccine Biology and Imunology, University of Rochester Medical Center, Rochester, NY 14642
| | - Gonzalo de la Rosa
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642; and David H. Smith Center for Vaccine Biology and Imunology, University of Rochester Medical Center, Rochester, NY 14642
| | - Christopher S Anderson
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642; and David H. Smith Center for Vaccine Biology and Imunology, University of Rochester Medical Center, Rochester, NY 14642
| | - Patrick S Murphy
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642; and David H. Smith Center for Vaccine Biology and Imunology, University of Rochester Medical Center, Rochester, NY 14642
| | - Tara Capece
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642; and David H. Smith Center for Vaccine Biology and Imunology, University of Rochester Medical Center, Rochester, NY 14642
| | - Minsoo Kim
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642; and David H. Smith Center for Vaccine Biology and Imunology, University of Rochester Medical Center, Rochester, NY 14642
| | - Michael R Elliott
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642; and David H. Smith Center for Vaccine Biology and Imunology, University of Rochester Medical Center, Rochester, NY 14642
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Damoulakis G, Gambardella L, Rossman KL, Lawson CD, Anderson KE, Fukui Y, Welch HC, Der CJ, Stephens LR, Hawkins PT. P-Rex1 directly activates RhoG to regulate GPCR-driven Rac signalling and actin polarity in neutrophils. J Cell Sci 2014; 127:2589-600. [PMID: 24659802 DOI: 10.1242/jcs.153049] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
G-protein-coupled receptors (GPCRs) regulate the organisation of the actin cytoskeleton by activating the Rac subfamily of small GTPases. The guanine-nucleotide-exchange factor (GEF) P-Rex1 is engaged downstream of GPCRs and phosphoinositide 3-kinase (PI3K) in many cell types, and promotes tumorigenic signalling and metastasis in breast cancer and melanoma, respectively. Although P-Rex1-dependent functions have been attributed to its GEF activity towards Rac1, we show that P-Rex1 also acts as a GEF for the Rac-related GTPase RhoG, both in vitro and in GPCR-stimulated primary mouse neutrophils. Furthermore, loss of either P-Rex1 or RhoG caused equivalent reductions in GPCR-driven Rac activation and Rac-dependent NADPH oxidase activity, suggesting they both function upstream of Rac in this system. Loss of RhoG also impaired GPCR-driven recruitment of the Rac GEF DOCK2, and F-actin, to the leading edge of migrating neutrophils. Taken together, our results reveal a new signalling hierarchy in which P-Rex1, acting as a GEF for RhoG, regulates Rac-dependent functions indirectly through RhoG-dependent recruitment of DOCK2. These findings thus have broad implications for our understanding of GPCR signalling to Rho GTPases and the actin cytoskeleton.
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Affiliation(s)
- George Damoulakis
- Inositide laboratory, Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK
| | - Laure Gambardella
- Inositide laboratory, Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK
| | - Kent L Rossman
- Lineberger Comprehensive Cancer Center and Department of Pharmacology, University of North Carolina at Chapel Hill, 450 West Drive, Chapel Hill, North Carolina, USA
| | - Campbell D Lawson
- Inositide laboratory, Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK
| | - Karen E Anderson
- Inositide laboratory, Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK
| | - Yoshinori Fukui
- Department of Immunobiology and Neuroscience, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan
| | - Heidi C Welch
- Inositide laboratory, Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK
| | - Channing J Der
- Lineberger Comprehensive Cancer Center and Department of Pharmacology, University of North Carolina at Chapel Hill, 450 West Drive, Chapel Hill, North Carolina, USA
| | - Len R Stephens
- Inositide laboratory, Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK
| | - Phillip T Hawkins
- Inositide laboratory, Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK
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41
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Eguchi K, Yoshioka Y, Yoshida H, Morishita K, Miyata S, Hiai H, Yamaguchi M. The Drosophila DOCK family protein sponge is involved in differentiation of R7 photoreceptor cells. Exp Cell Res 2013; 319:2179-95. [DOI: 10.1016/j.yexcr.2013.05.024] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2013] [Revised: 05/16/2013] [Accepted: 05/18/2013] [Indexed: 01/17/2023]
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Abstract
Small GTPases use GDP/GTP alternation to actuate a variety of functional switches that are pivotal for cell dynamics. The GTPase switch is turned on by GEFs, which stimulate dissociation of the tightly bound GDP, and turned off by GAPs, which accelerate the intrinsically sluggish hydrolysis of GTP. For Ras, Rho, and Rab GTPases, this switch incorporates a membrane/cytosol alternation regulated by GDIs and GDI-like proteins. The structures and core mechanisms of representative members of small GTPase regulators from most families have now been elucidated, illuminating their general traits combined with scores of unique features. Recent studies reveal that small GTPase regulators have themselves unexpectedly sophisticated regulatory mechanisms, by which they process cellular signals and build up specific cell responses. These mechanisms include multilayered autoinhibition with stepwise release, feedback loops mediated by the activated GTPase, feed-forward signaling flow between regulators and effectors, and a phosphorylation code for RhoGDIs. The flipside of these highly integrated functions is that they make small GTPase regulators susceptible to biochemical abnormalities that are directly correlated with diseases, notably a striking number of missense mutations in congenital diseases, and susceptible to bacterial mimics of GEFs, GAPs, and GDIs that take command of small GTPases in infections. This review presents an overview of the current knowledge of these many facets of small GTPase regulation.
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Affiliation(s)
- Jacqueline Cherfils
- Laboratoire d’Enzymologie et Biochimie Structurales, Centre National de la Recherche Scientifique, Centre deRecherche de Gif, Gif-sur-Yvette, France
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43
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Liu X, Li F, Pan Z, Wang W, Wen W. Solution structure of the SH3 domain of DOCK180. Proteins 2013; 81:906-10. [PMID: 23239367 DOI: 10.1002/prot.24236] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2012] [Revised: 11/09/2012] [Accepted: 11/28/2012] [Indexed: 11/07/2022]
Affiliation(s)
- Xiangrong Liu
- Key Laboratory of Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, Shanghai Medical College, Fudan University, Shanghai, People's Republic of China
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Hochreiter-Hufford A, Ravichandran KS. Clearing the dead: apoptotic cell sensing, recognition, engulfment, and digestion. Cold Spring Harb Perspect Biol 2013; 5:a008748. [PMID: 23284042 DOI: 10.1101/cshperspect.a008748] [Citation(s) in RCA: 368] [Impact Index Per Article: 33.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Clearance of apoptotic cells is the final stage of programmed cell death. Uncleared corpses can become secondarily necrotic, promoting inflammation and autoimmunity. Remarkably, even in tissues with high cellular turnover, apoptotic cells are rarely seen because of efficient clearance mechanisms in healthy individuals. Recently, significant progress has been made in understanding the steps involved in prompt cell clearance in vivo. These include the sensing of corpses via "find me" signals, the recognition of corpses via "eat me" signals and their cognate receptors, the signaling pathways that regulate cytoskeletal rearrangement necessary for engulfment, and the responses of the phagocyte that keep cell clearance events "immunologically silent." This study focuses on our understanding of these steps.
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Affiliation(s)
- Amelia Hochreiter-Hufford
- Department of Microbiology, Immunology and Cancer Biology, Center for Cell Clearance and Beirne Carter Center for Immunology Research, University of Virginia, Charlottesville, VA 22908, USA
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45
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Mauldin JP, Lu M, Das S, Park D, Ernst PB, Ravichandran KS. A link between the cytoplasmic engulfment protein Elmo1 and the Mediator complex subunit Med31. Curr Biol 2012; 23:162-7. [PMID: 23273896 DOI: 10.1016/j.cub.2012.11.049] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2011] [Revised: 10/29/2012] [Accepted: 11/26/2012] [Indexed: 01/06/2023]
Abstract
The cytoplasmic Elmo1:Dock180 complex acts as a guanine nucleotide exchange factor (GEF) for the small GTPase Rac and functions downstream of the phagocytic receptor BAI1 during apoptotic cell clearance, and in the entry of Salmonella and Shigella into cells. We discovered an unexpected binding between Elmo1 and the Mediator complex subunit Med31. The Mediator complex is a regulatory hub for nearly all gene transcription via RNA polymerase II, bridging the general transcription machinery with gene-specific regulatory proteins. Med31 is the smallest and the most evolutionarily conserved Mediator subunit, and knockout of Med31 results in embryonic lethality in mice; however, Med31 function in specific biological contexts is poorly understood. We observed that in primary macrophages, during Salmonella infection, Elmo1 and Med31 specifically affected expression of the cytokine genes Il10 and Il33 among the >25 genes monitored. Although endogenous Med31 is predominantly nuclear localized, Elmo1 increased the cytoplasmic localization of Med31. We identify ubiquitination as a novel posttranslational modification of Med31, with the cytoplasmic monoubiquitinated form of Med31 being enhanced by Elmo1. These data identify Elmo1 as a novel regulator of Med31, revealing a previously unrecognized link between cytoplasmic signaling proteins and the Mediator complex.
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Affiliation(s)
- Joshua P Mauldin
- Department of Cell Biology, University of Virginia, Charlottesville, VA 22908, USA
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46
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East MP, Bowzard JB, Dacks JB, Kahn RA. ELMO domains, evolutionary and functional characterization of a novel GTPase-activating protein (GAP) domain for Arf protein family GTPases. J Biol Chem 2012; 287:39538-53. [PMID: 23014990 DOI: 10.1074/jbc.m112.417477] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The human family of ELMO domain-containing proteins (ELMODs) consists of six members and is defined by the presence of the ELMO domain. Within this family are two subclassifications of proteins, based on primary sequence conservation, protein size, and domain architecture, deemed ELMOD and ELMO. In this study, we used homology searching and phylogenetics to identify ELMOD family homologs in genomes from across eukaryotic diversity. This demonstrated not only that the protein family is ancient but also that ELMOs are potentially restricted to the supergroup Opisthokonta (Metazoa and Fungi), whereas proteins with the ELMOD organization are found in diverse eukaryotes and thus were likely the form present in the last eukaryotic common ancestor. The segregation of the ELMO clade from the larger ELMOD group is consistent with their contrasting functions as unconventional Rac1 guanine nucleotide exchange factors and the Arf family GTPase-activating proteins, respectively. We used unbiased, phylogenetic sorting and sequence alignments to identify the most highly conserved residues within the ELMO domain to identify a putative GAP domain within the ELMODs. Three independent but complementary assays were used to provide an initial characterization of this domain. We identified a highly conserved arginine residue critical for both the biochemical and cellular GAP activity of ELMODs. We also provide initial evidence of the function of human ELMOD1 as an Arf family GAP at the Golgi. These findings provide the basis for the future study of the ELMOD family of proteins and a new avenue for the study of Arf family GTPases.
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Affiliation(s)
- Michael P East
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia 30322, USA
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Gonzalez-Billault C, Muñoz-Llancao P, Henriquez DR, Wojnacki J, Conde C, Caceres A. The role of small GTPases in neuronal morphogenesis and polarity. Cytoskeleton (Hoboken) 2012; 69:464-85. [PMID: 22605667 DOI: 10.1002/cm.21034] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2011] [Revised: 04/12/2012] [Accepted: 04/16/2012] [Indexed: 12/21/2022]
Abstract
The highly dynamic remodeling and cross talk of the microtubule and actin cytoskeleton support neuronal morphogenesis. Small RhoGTPases family members have emerged as crucial regulators of cytoskeletal dynamics. In this review we will comprehensively analyze findings that support the participation of RhoA, Rac, Cdc42, and TC10 in different neuronal morphogenetic events ranging from migration to synaptic plasticity. We will specifically address the contribution of these GTPases to support neuronal polarity and axonal elongation.
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Affiliation(s)
- Christian Gonzalez-Billault
- Faculty of Sciences, Laboratory of Cell and Neuronal Dynamics, Department of Biology and Institute for Cell Dynamics and Biotechnology, Universidad de Chile, Santiago, Chile.
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48
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Functional mechanisms and roles of adaptor proteins in abl-regulated cytoskeletal actin dynamics. JOURNAL OF SIGNAL TRANSDUCTION 2012; 2012:414913. [PMID: 22675626 PMCID: PMC3362954 DOI: 10.1155/2012/414913] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/16/2012] [Accepted: 03/16/2012] [Indexed: 01/20/2023]
Abstract
Abl is a nonreceptor tyrosine kinase and plays an essential role in the modeling and remodeling of F-actin by transducing extracellular signals. Abl and its paralog, Arg, are unique among the tyrosine kinase family in that they contain an unusual extended C-terminal half consisting of multiple functional domains. This structural characteristic may underlie the role of Abl as a mediator of upstream signals to downstream signaling machineries involved in actin dynamics. Indeed, a group of SH3-containing accessory proteins, or adaptor proteins, have been identified that bind to a proline-rich domain of the C-terminal portion of Abl and modulate its kinase activity, substrate recognition, and intracellular localization. Moreover, the existence of signaling cascade and biological outcomes unique to each adaptor protein has been demonstrated. In this paper, we summarize functional roles and mechanisms of adaptor proteins in Abl-regulated actin dynamics, mainly focusing on a family of adaptor proteins, Abi. The mechanism of Abl's activation and downstream signaling mediated by Abi is described in comparison with those by another adaptor protein, Crk.
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49
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Structural basis for mutual relief of the Rac guanine nucleotide exchange factor DOCK2 and its partner ELMO1 from their autoinhibited forms. Proc Natl Acad Sci U S A 2012; 109:3305-10. [PMID: 22331897 DOI: 10.1073/pnas.1113512109] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
DOCK2, a hematopoietic cell-specific, atypical guanine nucleotide exchange factor, controls lymphocyte migration through ras-related C3 botulinum toxin substrate (Rac) activation. Dedicator of cytokinesis 2-engulfment and cell motility protein 1 (DOCK2•ELMO1) complex formation is required for DOCK2-mediated Rac signaling. In this study, we identified the N-terminal 177-residue fragment and the C-terminal 196-residue fragment of human DOCK2 and ELMO1, respectively, as the mutual binding regions, and solved the crystal structure of their complex at 2.1-Å resolution. The C-terminal Pro-rich tail of ELMO1 winds around the Src-homology 3 domain of DOCK2, and an intermolecular five-helix bundle is formed. Overall, the entire regions of both DOCK2 and ELMO1 assemble to create a rigid structure, which is required for the DOCK2•ELMO1 binding, as revealed by mutagenesis. Intriguingly, the DOCK2•ELMO1 interface hydrophobically buries a residue which, when mutated, reportedly relieves DOCK180 from autoinhibition. We demonstrated that the ELMO-interacting region and the DOCK-homology region 2 guanine nucleotide exchange factor domain of DOCK2 associate with each other for the autoinhibition, and that the assembly with ELMO1 weakens the interaction, relieving DOCK2 from the autoinhibition. The interactions between the N- and C-terminal regions of ELMO1 reportedly cause its autoinhibition, and binding with a DOCK protein relieves the autoinhibition for ras homolog gene family, member G binding and membrane localization. In fact, the DOCK2•ELMO1 interface also buries the ELMO1 residues required for the autoinhibition within the hydrophobic core of the helix bundle. Therefore, the present complex structure reveals the structural basis by which DOCK2 and ELMO1 mutually relieve their autoinhibition for the activation of Rac1 for lymphocyte chemotaxis.
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50
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Sévajol M, Reiser JB, Chouquet A, Pérard J, Ayala I, Gans P, Kleman JP, Housset D. The C-terminal polyproline-containing region of ELMO contributes to an increase in the life-time of the ELMO-DOCK complex. Biochimie 2011; 94:823-8. [PMID: 22177965 DOI: 10.1016/j.biochi.2011.11.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2011] [Accepted: 11/29/2011] [Indexed: 10/14/2022]
Abstract
The eukaryotic Engulfment and CellMotility (ELMO) proteins form an evolutionary conserved family of key regulators which play a central role in Rho-dependent biological processes such as engulfment and cell motility/migration. ELMO proteins interact with a subset of Downstream of Crk (DOCK) family members, a new type of guanine exchange factors (GEF) for Rac and cdc42 GTPases. The physiological function of DOCK is to facilitate actin remodeling, a process which occurs only in presence of ELMO. Several studies have determined that the last 200 C-terminal residues of ELMO1 and the first 180 N-terminal residues of DOCK180 are responsible for the ELMO-DOCK interaction. However, the precise role of the different domains and motifs identified in these regions has remained elusive. Divergent functional, biochemical and structural data have been reported regarding the contribution of the C-terminal end of ELMO, comprising its polyproline motif, and of the DOCK SH3 domain. In the present study, we have investigated the contribution of the C-terminal end of ELMO1 to the interaction between ELMO1 and the SH3 domain of DOCK180 using nuclear magnetic resonance spectroscopy and surface plasmon resonance. Our data presented here demonstrate the ability of the SH3 domain of DOCK180 to interact with ELMO1, regardless of the presence of the polyproline-containing C-terminal end. However, the presence of the polyproline region leads to a significant increase in the half-life of the ELMO1-DOCK180 complex, along with a moderate increase on the affinity.
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Affiliation(s)
- Marion Sévajol
- Immune response to pathogens and altered-self group, Institut de Biologie Structurale Jean-Pierre Ebel, Commissariat à l'Energie Atomique et aux Energies Alternatives, Centre National de la Recherche Scientifique, Université Joseph Fourier-Grenoble 1, 41, rue Jules Horowitz, F-38027 Grenoble, France
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