1
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Weeratunga S, Gormal RS, Liu M, Eldershaw D, Livingstone EK, Malapaka A, Wallis TP, Bademosi AT, Jiang A, Healy MD, Meunier FA, Collins BM. Interrogation and validation of the interactome of neuronal Munc18-interacting Mint proteins with AlphaFold2. J Biol Chem 2024; 300:105541. [PMID: 38072052 PMCID: PMC10820826 DOI: 10.1016/j.jbc.2023.105541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 11/27/2023] [Accepted: 11/29/2023] [Indexed: 01/13/2024] Open
Abstract
Munc18-interacting proteins (Mints) are multidomain adaptors that regulate neuronal membrane trafficking, signaling, and neurotransmission. Mint1 and Mint2 are highly expressed in the brain with overlapping roles in the regulation of synaptic vesicle fusion required for neurotransmitter release by interacting with the essential synaptic protein Munc18-1. Here, we have used AlphaFold2 to identify and then validate the mechanisms that underpin both the specific interactions of neuronal Mint proteins with Munc18-1 as well as their wider interactome. We found that a short acidic α-helical motif within Mint1 and Mint2 is necessary and sufficient for specific binding to Munc18-1 and binds a conserved surface on Munc18-1 domain3b. In Munc18-1/2 double knockout neurosecretory cells, mutation of the Mint-binding site reduces the ability of Munc18-1 to rescue exocytosis, and although Munc18-1 can interact with Mint and Sx1a (Syntaxin1a) proteins simultaneously in vitro, we find that they have mutually reduced affinities, suggesting an allosteric coupling between the proteins. Using AlphaFold2 to then examine the entire cellular network of putative Mint interactors provides a structural model for their assembly with a variety of known and novel regulatory and cargo proteins including ADP-ribosylation factor (ARF3/ARF4) small GTPases and the AP3 clathrin adaptor complex. Validation of Mint1 interaction with a new predicted binder TJAP1 (tight junction-associated protein 1) provides experimental support that AlphaFold2 can correctly predict interactions across such large-scale datasets. Overall, our data provide insights into the diversity of interactions mediated by the Mint family and show that Mints may help facilitate a key trigger point in SNARE (soluble N-ethylmaleimide-sensitive factor attachment receptor) complex assembly and vesicle fusion.
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Affiliation(s)
- Saroja Weeratunga
- Institute for Molecular Bioscience, The University of Queensland, Queensland, Australia
| | - Rachel S Gormal
- Clem Jones Centre for Ageing and Dementia Research, Queensland Brain Institute, The University of Queensland, Queensland, Australia
| | - Meihan Liu
- Institute for Molecular Bioscience, The University of Queensland, Queensland, Australia
| | - Denaye Eldershaw
- Institute for Molecular Bioscience, The University of Queensland, Queensland, Australia
| | - Emma K Livingstone
- Institute for Molecular Bioscience, The University of Queensland, Queensland, Australia
| | - Anusha Malapaka
- Clem Jones Centre for Ageing and Dementia Research, Queensland Brain Institute, The University of Queensland, Queensland, Australia
| | - Tristan P Wallis
- Clem Jones Centre for Ageing and Dementia Research, Queensland Brain Institute, The University of Queensland, Queensland, Australia
| | - Adekunle T Bademosi
- Clem Jones Centre for Ageing and Dementia Research, Queensland Brain Institute, The University of Queensland, Queensland, Australia
| | - Anmin Jiang
- Clem Jones Centre for Ageing and Dementia Research, Queensland Brain Institute, The University of Queensland, Queensland, Australia
| | - Michael D Healy
- Institute for Molecular Bioscience, The University of Queensland, Queensland, Australia
| | - Frederic A Meunier
- Clem Jones Centre for Ageing and Dementia Research, Queensland Brain Institute, The University of Queensland, Queensland, Australia; School of Biomedical Sciences, The University of Queensland, Queensland, Australia
| | - Brett M Collins
- Institute for Molecular Bioscience, The University of Queensland, Queensland, Australia.
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2
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Sartre C, Peurois F, Ley M, Kryszke MH, Zhang W, Courilleau D, Fischmeister R, Ambroise Y, Zeghouf M, Cianferani S, Ferrandez Y, Cherfils J. Membranes prime the RapGEF EPAC1 to transduce cAMP signaling. Nat Commun 2023; 14:4157. [PMID: 37438343 DOI: 10.1038/s41467-023-39894-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Accepted: 06/30/2023] [Indexed: 07/14/2023] Open
Abstract
EPAC1, a cAMP-activated GEF for Rap GTPases, is a major transducer of cAMP signaling and a therapeutic target in cardiac diseases. The recent discovery that cAMP is compartmentalized in membrane-proximal nanodomains challenged the current model of EPAC1 activation in the cytosol. Here, we discover that anionic membranes are a major component of EPAC1 activation. We find that anionic membranes activate EPAC1 independently of cAMP, increase its affinity for cAMP by two orders of magnitude, and synergize with cAMP to yield maximal GEF activity. In the cell cytosol, where cAMP concentration is low, EPAC1 must thus be primed by membranes to bind cAMP. Examination of the cell-active chemical CE3F4 in this framework further reveals that it targets only fully activated EPAC1. Together, our findings reformulate previous concepts of cAMP signaling through EPAC proteins, with important implications for drug discovery.
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Affiliation(s)
- Candice Sartre
- Université Paris-Saclay, Ecole Normale Supérieure Paris-Saclay, CNRS, 91190, Gif-sur-Yvette, France
| | - François Peurois
- Université Paris-Saclay, Ecole Normale Supérieure Paris-Saclay, CNRS, 91190, Gif-sur-Yvette, France
| | - Marie Ley
- Laboratoire de Spectrométrie de Masse BioOrganique, Université de Strasbourg, IPHC, CNRS UMR 7178, Infrastructure Nationale de Protéomique ProFI - FR2048, 67087, Strasbourg, France
| | - Marie-Hélène Kryszke
- Université Paris-Saclay, Ecole Normale Supérieure Paris-Saclay, CNRS, 91190, Gif-sur-Yvette, France
| | - Wenhua Zhang
- Université Paris-Saclay, Ecole Normale Supérieure Paris-Saclay, CNRS, 91190, Gif-sur-Yvette, France
| | - Delphine Courilleau
- Université Paris-Saclay, IPSIT-CIBLOT, Inserm US31, CNRS UAR3679, 91400, Orsay, France
| | | | - Yves Ambroise
- Université Paris-Saclay, CEA, Service de Chimie Bioorganique et de Marquage, 91191, Gif-sur-Yvette, France
| | - Mahel Zeghouf
- Université Paris-Saclay, Ecole Normale Supérieure Paris-Saclay, CNRS, 91190, Gif-sur-Yvette, France
| | - Sarah Cianferani
- Laboratoire de Spectrométrie de Masse BioOrganique, Université de Strasbourg, IPHC, CNRS UMR 7178, Infrastructure Nationale de Protéomique ProFI - FR2048, 67087, Strasbourg, France
| | - Yann Ferrandez
- Université Paris-Saclay, Ecole Normale Supérieure Paris-Saclay, CNRS, 91190, Gif-sur-Yvette, France
| | - Jacqueline Cherfils
- Université Paris-Saclay, Ecole Normale Supérieure Paris-Saclay, CNRS, 91190, Gif-sur-Yvette, France.
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3
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Loose M, Auer A, Brognara G, Budiman HR, Kowalski L, Matijević I. In vitro
reconstitution of small
GTPase
regulation. FEBS Lett 2022; 597:762-777. [PMID: 36448231 DOI: 10.1002/1873-3468.14540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 10/27/2022] [Accepted: 11/07/2022] [Indexed: 12/05/2022]
Abstract
Small GTPases play essential roles in the organization of eukaryotic cells. In recent years, it has become clear that their intracellular functions result from intricate biochemical networks of the GTPase and their regulators that dynamically bind to a membrane surface. Due to the inherent complexities of their interactions, however, revealing the underlying mechanisms of action is often difficult to achieve from in vivo studies. This review summarizes in vitro reconstitution approaches developed to obtain a better mechanistic understanding of how small GTPase activities are regulated in space and time.
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Affiliation(s)
- Martin Loose
- Institute of Science and Technology Austria (ISTA) Klosterneuburg Austria
| | - Albert Auer
- Institute of Science and Technology Austria (ISTA) Klosterneuburg Austria
| | - Gabriel Brognara
- Institute of Science and Technology Austria (ISTA) Klosterneuburg Austria
| | | | - Lukasz Kowalski
- Institute of Science and Technology Austria (ISTA) Klosterneuburg Austria
| | - Ivana Matijević
- Institute of Science and Technology Austria (ISTA) Klosterneuburg Austria
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4
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Chen S, Shu L, Zhao R, Zhao Y. Molecular dynamics simulations reveal the activation mechanism of mutations G12V and Q61L of Cdc42. Proteins 2022; 90:1376-1389. [PMID: 35152498 DOI: 10.1002/prot.26320] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 01/26/2022] [Accepted: 02/09/2022] [Indexed: 12/12/2022]
Abstract
Cell division control protein 42 homolog (Cdc42), which contributes to multiple cellular processes including cell proliferation and migration, is a potential target for cancer therapy, especially in the intervention of tumor migration. Cdc42's mutants G12V and Q61L are discovered constitutively active, and the overexpression of them exhibits oncogenic activities. Here, using molecular dynamics (MD) simulations and dynamic analysis, we illustrated the activation mechanism of Cdc42G12V and Cdc42Q61L . Without GAP, the two mutations differently elicited state transition from the wild-type's open "inactive" state 1 to the closed "active" state 2, induced by the introduction of a newly formed water-mediated T35-γ-phosphate hydrogen bond in G12V system and the additional hydrophobic interactions between L61 and T35 together with the direct T35-γ-phosphate hydrogen bond in Q61L system. When binding with GAP, both mutations weakened the hydrogen bond interactions between Cdc42-GTP and GAP's finger loop, and disturbed the catalytically competent organizations of GAP's catalytic R305/R306 and Cdc42's Q61, thereby impairing the GAP-mediated GTP hydrolysis. Our findings first reveal the activation mechanism of Cdc42's G12V and Q61L mutants on a molecular basis, which provide new insights into the structural and dynamical characteristics of Cdc42 and its mutants and can be exploited in the further development of novel therapies targeting Cdc42-related cancers.
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Affiliation(s)
- Shiyao Chen
- School of Pharmacy, Shanghai Jiao Tong University, Shanghai, China
| | - Liang Shu
- Department of Neurology, Shanghai Ninth People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Rong Zhao
- Department of Neurology, Shanghai Ninth People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Yaxue Zhao
- School of Pharmacy, Shanghai Jiao Tong University, Shanghai, China
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5
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Mei Q, Li H, Liu Y, Wang X, Xiang W. Advances in the study of CDC42 in the female reproductive system. J Cell Mol Med 2021; 26:16-24. [PMID: 34859585 PMCID: PMC8742232 DOI: 10.1111/jcmm.17088] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 11/08/2021] [Accepted: 11/12/2021] [Indexed: 12/19/2022] Open
Abstract
CDC42 is a member of the Rho‐GTPase family and is involved in a variety of cellular functions including regulation of cell cycle progression, constitution of the actin backbone and membrane transport. In particular, CDC42 plays a key role in the establishment of polarity in female vertebrate oocytes, and essential to this major regulatory role is its local occupation of specific regions of the cell to ensure that the contractile ring is assembled at the right time and place to ensure proper gametogenesis. The multifactor controlled ‘inactivation‐activation’ process of CDC42 also allows it to play an important role in the multilevel signalling network, and the synergistic regulation of multiple genes ensures maximum precision during gametogenesis. The purpose of this paper is to review the role of CDC42 in the control of gametogenesis and to explore its related mechanisms, with the aim of further understanding the great research potential of CDC42 in female vertebrate germ cells and its future clinical translation.
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Affiliation(s)
- Qiaojuan Mei
- Institute of Reproductive Health and Center for Reproductive Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Huiying Li
- Institute of Reproductive Health and Center for Reproductive Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yu Liu
- Institute of Reproductive Health and Center for Reproductive Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xiaofei Wang
- Institute of Reproductive Health and Center for Reproductive Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Wenpei Xiang
- Institute of Reproductive Health and Center for Reproductive Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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6
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Trillet K, Jacobs KA, André-Grégoire G, Thys A, Maghe C, Cruard J, Minvielle S, Diest SG, Montagnac G, Bidère N, Gavard J. The glycoprotein GP130 governs the surface presentation of the G protein-coupled receptor APLNR. J Cell Biol 2021; 220:212489. [PMID: 34287648 PMCID: PMC8298102 DOI: 10.1083/jcb.202004114] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 12/29/2020] [Accepted: 05/27/2021] [Indexed: 12/28/2022] Open
Abstract
Glioblastoma is one of the most lethal forms of adult cancer, with a median survival of ∼15 mo. Targeting glioblastoma stem-like cells (GSCs) at the origin of tumor formation and relapse may prove beneficial. In situ, GSCs are nested within the vascular bed in tight interaction with brain endothelial cells, which positively control their expansion. Because GSCs are notably addicted to apelin (APLN), sourced from the surrounding endothelial stroma, the APLN/APLNR nexus has emerged as a druggable network. However, how this signaling axis operates in gliomagenesis remains underestimated. Here, we find that the glycoprotein GP130 interacts with APLNR at the plasma membrane of GSCs and arbitrates its availability at the surface via ELMOD1, which may further impact on ARF-mediated endovesicular trafficking. From a functional standpoint, interfering with GP130 thwarts APLNR-mediated self-renewal of GSCs ex vivo. Thus, GP130 emerges as an unexpected cicerone to the G protein–coupled APLN receptor, opening new therapeutic perspectives toward the targeting of cancer stem cells.
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Affiliation(s)
- Kilian Trillet
- Centre de Recherche en Cancérologie et Immunologie Nantes Angers, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Université de Nantes, Université d'Angers, Nantes, France
| | - Kathryn A Jacobs
- Centre de Recherche en Cancérologie et Immunologie Nantes Angers, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Université de Nantes, Université d'Angers, Nantes, France
| | - Gwennan André-Grégoire
- Centre de Recherche en Cancérologie et Immunologie Nantes Angers, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Université de Nantes, Université d'Angers, Nantes, France.,Integrated Center for Oncology, St. Herblain, France
| | - An Thys
- Centre de Recherche en Cancérologie et Immunologie Nantes Angers, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Université de Nantes, Université d'Angers, Nantes, France
| | - Clément Maghe
- Centre de Recherche en Cancérologie et Immunologie Nantes Angers, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Université de Nantes, Université d'Angers, Nantes, France
| | - Jonathan Cruard
- Centre de Recherche en Cancérologie et Immunologie Nantes Angers, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Université de Nantes, Université d'Angers, Nantes, France
| | - Stéphane Minvielle
- Centre de Recherche en Cancérologie et Immunologie Nantes Angers, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Université de Nantes, Université d'Angers, Nantes, France
| | - Sara Gonzalez Diest
- Centre de Recherche en Cancérologie et Immunologie Nantes Angers, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Université de Nantes, Université d'Angers, Nantes, France
| | - Guillaume Montagnac
- Institut National de la Santé et de la Recherche Médicale U1279, Gustave Roussy Institute, Université Paris-Saclay, Villejuif, France
| | - Nicolas Bidère
- Centre de Recherche en Cancérologie et Immunologie Nantes Angers, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Université de Nantes, Université d'Angers, Nantes, France
| | - Julie Gavard
- Centre de Recherche en Cancérologie et Immunologie Nantes Angers, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Université de Nantes, Université d'Angers, Nantes, France.,Integrated Center for Oncology, St. Herblain, France
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7
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Bircher JE, Koleske AJ. Trio family proteins as regulators of cell migration and morphogenesis in development and disease - mechanisms and cellular contexts. J Cell Sci 2021; 134:jcs248393. [PMID: 33568469 PMCID: PMC7888718 DOI: 10.1242/jcs.248393] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The well-studied members of the Trio family of proteins are Trio and kalirin in vertebrates, UNC-73 in Caenorhabditis elegans and Trio in Drosophila Trio proteins are key regulators of cell morphogenesis and migration, tissue organization, and secretion and protein trafficking in many biological contexts. Recent discoveries have linked Trio and kalirin to human disease, including neurological disorders and cancer. The genes for Trio family proteins encode a series of large multidomain proteins with up to three catalytic activities and multiple scaffolding and protein-protein interaction domains. As such, Trio family proteins engage a wide array of cell surface receptors, substrates and interaction partners to coordinate changes in cytoskeletal regulatory and protein trafficking pathways. We provide a comprehensive review of the specific mechanisms by which Trio family proteins carry out their functions in cells, highlight the biological and cellular contexts in which they occur, and relate how alterations in these functions contribute to human disease.
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Affiliation(s)
- Josie E Bircher
- Department of Molecular Biochemistry and Biophysics, Yale School of Medicine, Yale University, New Haven, CT 06511 USA
| | - Anthony J Koleske
- Department of Molecular Biochemistry and Biophysics, Yale School of Medicine, Yale University, New Haven, CT 06511 USA
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8
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Mounier L, Morel A, Ferrandez Y, Morko J, Vääräniemi J, Gilardone M, Roche D, Cherfils J, Blangy A. Novel 2,7-Diazaspiro[4,4]nonane Derivatives to Inhibit Mouse and Human Osteoclast Activities and Prevent Bone Loss in Ovariectomized Mice without Affecting Bone Formation. J Med Chem 2020; 63:13680-13694. [PMID: 33175535 DOI: 10.1021/acs.jmedchem.0c01201] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Osteoporosis is currently treated with drugs targeting the differentiation or viability osteoclasts, the cells responsible for physiological and pathological bone resorption. Nevertheless, osteoporosis drugs that target only osteoclast activity are expected to preserve bone formation by osteoblasts in contrast to current treatments. We report here the design, synthesis, and biological characterization of a series of novel N-arylsufonamides featuring a diazaspiro[4,4]nonane nucleus to target the guanine nucleotide exchange activity of DOCK5, which is essential for bone resorption by osteoclasts. These compounds can inhibit both mouse and human osteoclast activity. In particular, 4-chlorobenzyl-4-hydroxy-2-phenyl-1-thia-2,7-diazaspiro[4,4]nonane 1,1-dioxide (compound E197) prevented pathological bone loss in mice. Most interestingly, treatment with E197 did not affect osteoclast and osteoblast numbers and hence did not impair bone formation. E197 could represent a lead molecule to develop new antiosteoporotic drugs targeting the mechanism of osteoclast adhesion onto the bone.
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Affiliation(s)
- Lucile Mounier
- Centre de Recherche en Biologie Cellulaire de Montpellier, Univ Montpellier, CNRS, Montpellier, France, Université de Montpellier, CNRS, 34000 Montpellier, France
| | - Anne Morel
- Centre de Recherche en Biologie Cellulaire de Montpellier, Univ Montpellier, CNRS, Montpellier, France, Université de Montpellier, CNRS, 34000 Montpellier, France
| | - Yann Ferrandez
- Laboratoire de Biologie et Pharmacologie Appliquée, CNRS, Ecole Normale Supérieure Paris-Saclay and Université Paris-Saclay, 91190 Gif-sur-Yvette, France
| | - Jukka Morko
- Pharmatest Services Ltd., Itäinen Pitkäkatu 4, 20520 Turku, Finland
| | - Jukka Vääräniemi
- Pharmatest Services Ltd., Itäinen Pitkäkatu 4, 20520 Turku, Finland
| | | | - Didier Roche
- Edelris, 60 Avenue Rockefeller, 69008 Lyon, France
| | - Jacqueline Cherfils
- Laboratoire de Biologie et Pharmacologie Appliquée, CNRS, Ecole Normale Supérieure Paris-Saclay and Université Paris-Saclay, 91190 Gif-sur-Yvette, France
| | - Anne Blangy
- Centre de Recherche en Biologie Cellulaire de Montpellier, Univ Montpellier, CNRS, Montpellier, France, Université de Montpellier, CNRS, 34000 Montpellier, France
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9
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Abstract
Rho GTPases are known to play an essential role in fundamental processes such as defining cell shape, polarity and migration. As such, the majority of Rho GTPases localize and function at, or close to, the plasma membrane. However, it is becoming increasingly clear that a number of Rho family proteins are also associated with the Golgi complex, where they not only regulate events at this organelle but also more widely across the cell. Given the central location of this organelle, and the numerous membrane trafficking pathways that connect it to both the endocytic and secretory systems of cells, it is clear that the Golgi is fundamental for maintaining cellular homoeostasis. In this review, we describe these GTPases in the context of how they regulate Golgi architecture, membrane trafficking into and away from this organelle, and cell polarity and migration. We summarize the key findings that show the growing importance of the pool of Rho GTPases associated with Golgi function, namely Cdc42, RhoA, RhoD, RhoBTB1 and RhoBTB3, and we discuss how they act in concert with other key families of molecules associated with the Golgi, including Rab GTPases and matrix proteins.
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Affiliation(s)
- Margaritha M Mysior
- Cell Screening Laboratory, School of Biology & Environmental Science, University College Dublin (UCD), Dublin Ireland
| | - Jeremy C Simpson
- Cell Screening Laboratory, School of Biology & Environmental Science, University College Dublin (UCD), Dublin Ireland
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10
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Swart AL, Hilbi H. Phosphoinositides and the Fate of Legionella in Phagocytes. Front Immunol 2020; 11:25. [PMID: 32117224 PMCID: PMC7025538 DOI: 10.3389/fimmu.2020.00025] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Accepted: 01/08/2020] [Indexed: 01/28/2023] Open
Abstract
Legionella pneumophila is the causative agent of a severe pneumonia called Legionnaires' disease. The environmental bacterium replicates in free-living amoebae as well as in lung macrophages in a distinct compartment, the Legionella-containing vacuole (LCV). The LCV communicates with a number of cellular vesicle trafficking pathways and is formed by a plethora of secreted bacterial effector proteins, which target host cell proteins and lipids. Phosphoinositide (PI) lipids are pivotal determinants of organelle identity, membrane dynamics and vesicle trafficking. Accordingly, eukaryotic cells tightly regulate the production, turnover, interconversion, and localization of PI lipids. L. pneumophila modulates the PI pattern in infected cells for its own benefit by (i) recruiting PI-decorated vesicles, (ii) producing effectors acting as PI interactors, phosphatases, kinases or phospholipases, and (iii) subverting host PI metabolizing enzymes. The PI conversion from PtdIns(3)P to PtdIns(4)P represents a decisive step during LCV maturation. In this review, we summarize recent progress on elucidating the strategies, by which L. pneumophila subverts host PI lipids to promote LCV formation and intracellular replication.
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Affiliation(s)
- A Leoni Swart
- Faculty of Medicine, Institute of Medical Microbiology, University of Zürich, Zurich, Switzerland
| | - Hubert Hilbi
- Faculty of Medicine, Institute of Medical Microbiology, University of Zürich, Zurich, Switzerland
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11
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Structural Organization and Dynamics of Homodimeric Cytohesin Family Arf GTPase Exchange Factors in Solution and on Membranes. Structure 2019; 27:1782-1797.e7. [PMID: 31601460 PMCID: PMC6948192 DOI: 10.1016/j.str.2019.09.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 09/03/2019] [Accepted: 09/16/2019] [Indexed: 12/30/2022]
Abstract
Membrane dynamic processes require Arf GTPase activation by guanine nucleotide exchange factors (GEFs) with a Sec7 domain. Cytohesin family Arf GEFs function in signaling and cell migration through Arf GTPase activation on the plasma membrane and endosomes. In this study, the structural organization of two cytohesins (Grp1 and ARNO) was investigated in solution by size exclusion-small angle X-ray scattering and negative stain-electron microscopy and on membranes by dynamic light scattering, hydrogen-deuterium exchange-mass spectrometry and guanosine diphosphate (GDP)/guanosine triphosphate (GTP) exchange assays. The results suggest that cytohesins form elongated dimers with a central coiled coil and membrane-binding pleckstrin-homology (PH) domains at opposite ends. The dimers display significant conformational heterogeneity, with a preference for compact to intermediate conformations. Phosphoinositide-dependent membrane recruitment is mediated by one PH domain at a time and alters the conformational dynamics to prime allosteric activation by Arf-GTP. A structural model for membrane targeting and allosteric activation of full-length cytohesin dimers is discussed.
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12
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Identification of the guanine nucleotide exchange factor for SAR1 in the filamentous fungal model Aspergillus nidulans. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2019; 1866:118551. [PMID: 31487505 DOI: 10.1016/j.bbamcr.2019.118551] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 08/02/2019] [Accepted: 08/11/2019] [Indexed: 12/30/2022]
Abstract
In spite of its basic and applied interest, the regulation of ER exit by filamentous fungi is insufficiently understood. In previous work we isolated a panel of conditional mutations in sarA encoding the master GTPase SarASAR1 in A. nidulans and demonstrated its key role in exocytosis and hyphal morphogenesis. However, the SAR1 guanine nucleotide exchange factor (GEF), Sec12, has not been characterized in any filamentous fungus, largely due to the fact that SEC12 homologues share little amino acid sequence identity beyond a GGGGxxxxGϕxN motif involved in guanine nucleotide exchange. Here we demonstrate that AN11127 encodes A. nidulans Sec12, which is an essential protein that localizes to the ER and that, when overexpressed, rescues the growth defect resulting from a hypomorphic sarA6ts mutation at 37 °C. Using purified, bacterially expressed proteins we demonstrate that the product of AN11127 accelerates nucleotide exchange on SarASAR1, but not on its closely related GTPase ArfAARF1, as expected for a bona fide GEF. The unequivocal characterization of A. nidulans Sec12 paves the way for the tailored modification of ER exit in a model organism that is closely related to industrial species of filamentous fungi.
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13
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Vestre K, Kjos I, Guadagno NA, Borg Distefano M, Kohler F, Fenaroli F, Bakke O, Progida C. Rab6 regulates cell migration and invasion by recruiting Cdc42 and modulating its activity. Cell Mol Life Sci 2019; 76:2593-2614. [PMID: 30830239 PMCID: PMC11105640 DOI: 10.1007/s00018-019-03057-w] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 02/08/2019] [Accepted: 02/26/2019] [Indexed: 12/22/2022]
Abstract
Rab proteins are master regulators of intracellular membrane trafficking, but they also contribute to cell division, signaling, polarization, and migration. The majority of the works describing the mechanisms used by Rab proteins to regulate cell motility involve intracellular transport of key molecules important for migration. Interestingly, a few studies indicate that Rabs can modulate the activity of Rho GTPases, important regulators for the cytoskeleton rearrangements, but the mechanisms behind this crosstalk are still poorly understood. In this work, we identify Rab6 as a negative regulator of cell migration in vitro and in vivo. We show that the loss of Rab6 promotes formation of actin protrusions and influences actomyosin dynamics by upregulating Cdc42 activity and downregulating myosin II phosphorylation. We further provide the molecular mechanism behind this regulation demonstrating that Rab6 interacts with both Cdc42 and Trio, a GEF for Cdc42. In sum, our results uncover a mechanism used by Rab proteins to ensure spatial regulation of Rho GTPase activity for coordination of cytoskeleton rearrangements required in migrating cells.
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Affiliation(s)
- Katharina Vestre
- Department of Biosciences, University of Oslo, Oslo, Norway
- Centre for Immune Regulation, University of Oslo, Oslo, Norway
| | - Ingrid Kjos
- Department of Biosciences, University of Oslo, Oslo, Norway
- Centre for Immune Regulation, University of Oslo, Oslo, Norway
| | - Noemi Antonella Guadagno
- Department of Biosciences, University of Oslo, Oslo, Norway
- Centre for Immune Regulation, University of Oslo, Oslo, Norway
| | - Marita Borg Distefano
- Department of Biosciences, University of Oslo, Oslo, Norway
- Centre for Immune Regulation, University of Oslo, Oslo, Norway
| | - Felix Kohler
- Department of Physics, The NJORD Centre, University of Oslo, Oslo, Norway
| | | | - Oddmund Bakke
- Department of Biosciences, University of Oslo, Oslo, Norway
- Centre for Immune Regulation, University of Oslo, Oslo, Norway
| | - Cinzia Progida
- Department of Biosciences, University of Oslo, Oslo, Norway.
- Centre for Immune Regulation, University of Oslo, Oslo, Norway.
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14
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Sztul E, Chen PW, Casanova JE, Cherfils J, Dacks JB, Lambright DG, Lee FJS, Randazzo PA, Santy LC, Schürmann A, Wilhelmi I, Yohe ME, Kahn RA. ARF GTPases and their GEFs and GAPs: concepts and challenges. Mol Biol Cell 2019; 30:1249-1271. [PMID: 31084567 PMCID: PMC6724607 DOI: 10.1091/mbc.e18-12-0820] [Citation(s) in RCA: 149] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Revised: 02/26/2019] [Accepted: 03/11/2019] [Indexed: 12/12/2022] Open
Abstract
Detailed structural, biochemical, cell biological, and genetic studies of any gene/protein are required to develop models of its actions in cells. Studying a protein family in the aggregate yields additional information, as one can include analyses of their coevolution, acquisition or loss of functionalities, structural pliability, and the emergence of shared or variations in molecular mechanisms. An even richer understanding of cell biology can be achieved through evaluating functionally linked protein families. In this review, we summarize current knowledge of three protein families: the ARF GTPases, the guanine nucleotide exchange factors (ARF GEFs) that activate them, and the GTPase-activating proteins (ARF GAPs) that have the ability to both propagate and terminate signaling. However, despite decades of scrutiny, our understanding of how these essential proteins function in cells remains fragmentary. We believe that the inherent complexity of ARF signaling and its regulation by GEFs and GAPs will require the concerted effort of many laboratories working together, ideally within a consortium to optimally pool information and resources. The collaborative study of these three functionally connected families (≥70 mammalian genes) will yield transformative insights into regulation of cell signaling.
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Affiliation(s)
- Elizabeth Sztul
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Pei-Wen Chen
- Department of Biology, Williams College, Williamstown, MA 01267
| | - James E. Casanova
- Department of Cell Biology, University of Virginia, Charlottesville, VA 22908
| | - Jacqueline Cherfils
- Laboratoire de Biologie et Pharmacologie Appliquée, CNRS and Ecole Normale Supérieure Paris-Saclay, 94235 Cachan, France
| | - Joel B. Dacks
- Division of Infectious Disease, Department of Medicine, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - David G. Lambright
- Program in Molecular Medicine and Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Amherst, MA 01605
| | - Fang-Jen S. Lee
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei 10002, Taiwan
| | | | - Lorraine C. Santy
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA 16802
| | - Annette Schürmann
- German Institute of Human Nutrition, 85764 Potsdam-Rehbrücke, Germany
| | - Ilka Wilhelmi
- German Institute of Human Nutrition, 85764 Potsdam-Rehbrücke, Germany
| | - Marielle E. Yohe
- Pediatric Oncology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892
| | - Richard A. Kahn
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322-3050
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15
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Møller LLV, Klip A, Sylow L. Rho GTPases-Emerging Regulators of Glucose Homeostasis and Metabolic Health. Cells 2019; 8:E434. [PMID: 31075957 PMCID: PMC6562660 DOI: 10.3390/cells8050434] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 05/02/2019] [Accepted: 05/06/2019] [Indexed: 12/11/2022] Open
Abstract
Rho guanosine triphosphatases (GTPases) are key regulators in a number of cellular functions, including actin cytoskeleton remodeling and vesicle traffic. Traditionally, Rho GTPases are studied because of their function in cell migration and cancer, while their roles in metabolism are less documented. However, emerging evidence implicates Rho GTPases as regulators of processes of crucial importance for maintaining metabolic homeostasis. Thus, the time is now ripe for reviewing Rho GTPases in the context of metabolic health. Rho GTPase-mediated key processes include the release of insulin from pancreatic β cells, glucose uptake into skeletal muscle and adipose tissue, and muscle mass regulation. Through the current review, we cast light on the important roles of Rho GTPases in skeletal muscle, adipose tissue, and the pancreas and discuss the proposed mechanisms by which Rho GTPases act to regulate glucose metabolism in health and disease. We also describe challenges and goals for future research.
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Affiliation(s)
- Lisbeth Liliendal Valbjørn Møller
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, 2100 Copenhagen Oe, Denmark.
| | - Amira Klip
- Cell Biology Program, The Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada.
| | - Lykke Sylow
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, 2100 Copenhagen Oe, Denmark.
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16
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Bhatt JM, Hancock W, Meissner JM, Kaczmarczyk A, Lee E, Viktorova E, Ramanadham S, Belov GA, Sztul E. Promiscuity of the catalytic Sec7 domain within the guanine nucleotide exchange factor GBF1 in ARF activation, Golgi homeostasis, and effector recruitment. Mol Biol Cell 2019; 30:1523-1535. [PMID: 30943106 PMCID: PMC6724685 DOI: 10.1091/mbc.e18-11-0711] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The integrity of the Golgi and trans-Golgi network (TGN) is disrupted by brefeldin A (BFA), which inhibits the Golgi-localized BFA-sensitive factor (GBF1) and brefeldin A-inhibited guanine nucleotide-exchange factors (BIG1 and BIG2). Using a cellular replacement assay to assess GBF1 functionality without interference from the BIGs, we show that GBF1 alone maintains Golgi architecture; facilitates secretion; activates ADP-ribosylation factor (ARF)1, 3, 4, and 5; and recruits ARF effectors to Golgi membranes. Unexpectedly, GBF1 also supports TGN integrity and recruits numerous TGN-localized ARF effectors. The impact of the catalytic Sec7 domain (Sec7d) on GBF1 functionality was assessed by swapping it with the Sec7d from ARF nucleotide-binding site opener (ARNO)/cytohesin-2, a plasma membrane GEF reported to activate all ARFs. The resulting chimera (GBF1-ARNO-GBF1 [GARG]) targets like GBF1, supports Golgi/TGN architecture, and facilitates secretion. However, unlike GBF1, GARG activates all ARFs (including ARF6) at the Golgi/TGN and recruits additional ARF effectors to the Golgi/TGN. Our results have general implications: 1) GEF's targeting is independent of Sec7d, but Sec7d influence the GEF substrate specificity and downstream effector events; 2) all ARFs have access to all membranes, but are restricted in their distribution by the localization of their activating GEFs; and 3) effector association with membranes requires the coincidental presence of activated ARFs and specific membrane identifiers.
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Affiliation(s)
- Jay M Bhatt
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35294
| | - William Hancock
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Justyna M Meissner
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Aneta Kaczmarczyk
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Eunjoo Lee
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Ekaterina Viktorova
- Department of Veterinary Medicine, Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, MD 20742
| | - Sasanka Ramanadham
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35294.,Comprehensive Diabetes Center, University of Alabama at Birmingham, Birmingham, AL 35294
| | - George A Belov
- Department of Veterinary Medicine, Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, MD 20742
| | - Elizabeth Sztul
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35294
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17
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Nawrotek A, Benabdi S, Niyomchon S, Kryszke MH, Ginestier C, Cañeque T, Tepshi L, Mariani A, St Onge RP, Giaever G, Nislow C, Charafe-Jauffret E, Rodriguez R, Zeghouf M, Cherfils J. PH-domain-binding inhibitors of nucleotide exchange factor BRAG2 disrupt Arf GTPase signaling. Nat Chem Biol 2019; 15:358-366. [PMID: 30742123 DOI: 10.1038/s41589-019-0228-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2018] [Accepted: 11/29/2018] [Indexed: 12/30/2022]
Abstract
Peripheral membrane proteins orchestrate many physiological and pathological processes, making regulation of their activities by small molecules highly desirable. However, they are often refractory to classical competitive inhibition. Here, we demonstrate that potent and selective inhibition of peripheral membrane proteins can be achieved by small molecules that target protein-membrane interactions by a noncompetitive mechanism. We show that the small molecule Bragsin inhibits BRAG2-mediated Arf GTPase activation in vitro in a manner that requires a membrane. In cells, Bragsin affects the trans-Golgi network in a BRAG2- and Arf-dependent manner. The crystal structure of the BRAG2-Bragsin complex and structure-activity relationship analysis reveal that Bragsin binds at the interface between the PH domain of BRAG2 and the lipid bilayer to render BRAG2 unable to activate lipidated Arf. Finally, Bragsin affects tumorsphere formation in breast cancer cell lines. Bragsin thus pioneers a novel class of drugs that function by altering protein-membrane interactions without disruption.
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Affiliation(s)
- Agata Nawrotek
- Laboratoire de Biologie et Pharmacologie Appliquée, Ecole normale supérieure Paris-Saclay, Cachan, France.,CNRS, Cachan, France
| | - Sarah Benabdi
- Laboratoire de Biologie et Pharmacologie Appliquée, Ecole normale supérieure Paris-Saclay, Cachan, France.,CNRS, Cachan, France
| | - Supaporn Niyomchon
- Institut Curie, PSL Research University, Chemical Cell Biology Group, Paris, France.,CNRS, Paris, France.,INSERM, Paris, France
| | - Marie-Hélène Kryszke
- Laboratoire de Biologie et Pharmacologie Appliquée, Ecole normale supérieure Paris-Saclay, Cachan, France.,CNRS, Cachan, France
| | - Christophe Ginestier
- Université Aix-Marseille, CNRS, INSERM, Institut Paoli-Calmettes, CRCM, Epithelial Stem Cells and Cancer Team, Marseille, France
| | - Tatiana Cañeque
- Institut Curie, PSL Research University, Chemical Cell Biology Group, Paris, France.,CNRS, Paris, France.,INSERM, Paris, France
| | - Livia Tepshi
- Laboratoire de Biologie et Pharmacologie Appliquée, Ecole normale supérieure Paris-Saclay, Cachan, France.,CNRS, Cachan, France
| | - Angelica Mariani
- Institut Curie, PSL Research University, Chemical Cell Biology Group, Paris, France.,CNRS, Paris, France.,INSERM, Paris, France
| | - Robert P St Onge
- Genome Technology Center, Stanford School of Medicine, Stanford, CA, USA
| | - Guri Giaever
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, Canada
| | - Corey Nislow
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, Canada
| | - Emmanuelle Charafe-Jauffret
- Université Aix-Marseille, CNRS, INSERM, Institut Paoli-Calmettes, CRCM, Epithelial Stem Cells and Cancer Team, Marseille, France
| | - Raphaël Rodriguez
- Institut Curie, PSL Research University, Chemical Cell Biology Group, Paris, France.,CNRS, Paris, France.,INSERM, Paris, France
| | - Mahel Zeghouf
- Laboratoire de Biologie et Pharmacologie Appliquée, Ecole normale supérieure Paris-Saclay, Cachan, France. .,CNRS, Cachan, France.
| | - Jacqueline Cherfils
- Laboratoire de Biologie et Pharmacologie Appliquée, Ecole normale supérieure Paris-Saclay, Cachan, France. .,CNRS, Cachan, France.
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18
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Huang QY, Lai XN, Qian XL, Lv LC, Li J, Duan J, Xiao XH, Xiong LX. Cdc42: A Novel Regulator of Insulin Secretion and Diabetes-Associated Diseases. Int J Mol Sci 2019; 20:ijms20010179. [PMID: 30621321 PMCID: PMC6337499 DOI: 10.3390/ijms20010179] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2018] [Revised: 12/26/2018] [Accepted: 12/29/2018] [Indexed: 02/07/2023] Open
Abstract
Cdc42, a member of the Rho GTPases family, is involved in the regulation of several cellular functions including cell cycle progression, survival, transcription, actin cytoskeleton organization and membrane trafficking. Diabetes is a chronic and metabolic disease, characterized as glycometabolism disorder induced by insulin deficiency related to β cell dysfunction and peripheral insulin resistance (IR). Diabetes could cause many complications including diabetic nephropathy (DN), diabetic retinopathy and diabetic foot. Furthermore, hyperglycemia can promote tumor progression and increase the risk of malignant cancers. In this review, we summarized the regulation of Cdc42 in insulin secretion and diabetes-associated diseases. Organized researches indicate that Cdc42 is a crucial member during the progression of diabetes, and Cdc42 not only participates in the process of insulin synthesis but also regulates the insulin granule mobilization and cell membrane exocytosis via activating a series of downstream factors. Besides, several studies have demonstrated Cdc42 as participating in the pathogenesis of IR and DN and even contributing to promote cancer cell proliferation, survival, invasion, migration, and metastasis under hyperglycemia. Through the current review, we hope to cast light on the mechanism of Cdc42 in diabetes and associated diseases and provide new ideas for clinical diagnosis, treatment, and prevention.
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Affiliation(s)
- Qi-Yuan Huang
- Department of Pathophysiology, Medical College, Nanchang University, Jiangxi Province Key Laboratory of Tumor Pathogenesis and Molecular Pathology, 461 Bayi Road, Nanchang 330006, China.
| | - Xing-Ning Lai
- Department of Pathophysiology, Medical College, Nanchang University, Jiangxi Province Key Laboratory of Tumor Pathogenesis and Molecular Pathology, 461 Bayi Road, Nanchang 330006, China.
| | - Xian-Ling Qian
- Department of Pathophysiology, Medical College, Nanchang University, Jiangxi Province Key Laboratory of Tumor Pathogenesis and Molecular Pathology, 461 Bayi Road, Nanchang 330006, China.
| | - Lin-Chen Lv
- Department of Pathophysiology, Medical College, Nanchang University, Jiangxi Province Key Laboratory of Tumor Pathogenesis and Molecular Pathology, 461 Bayi Road, Nanchang 330006, China.
| | - Jun Li
- Department of Pathophysiology, Medical College, Nanchang University, Jiangxi Province Key Laboratory of Tumor Pathogenesis and Molecular Pathology, 461 Bayi Road, Nanchang 330006, China.
| | - Jing Duan
- Department of Pathophysiology, Medical College, Nanchang University, Jiangxi Province Key Laboratory of Tumor Pathogenesis and Molecular Pathology, 461 Bayi Road, Nanchang 330006, China.
| | - Xing-Hua Xiao
- Department of Pathophysiology, Medical College, Nanchang University, Jiangxi Province Key Laboratory of Tumor Pathogenesis and Molecular Pathology, 461 Bayi Road, Nanchang 330006, China.
| | - Li-Xia Xiong
- Department of Pathophysiology, Medical College, Nanchang University, Jiangxi Province Key Laboratory of Tumor Pathogenesis and Molecular Pathology, 461 Bayi Road, Nanchang 330006, China.
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19
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Small GTPase peripheral binding to membranes: molecular determinants and supramolecular organization. Biochem Soc Trans 2018; 47:13-22. [PMID: 30559268 DOI: 10.1042/bst20170525] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 11/23/2018] [Accepted: 11/27/2018] [Indexed: 01/26/2023]
Abstract
Small GTPases regulate many aspects of cell logistics by alternating between an inactive, GDP-bound form and an active, GTP-bound form. This nucleotide switch is coupled to a cytosol/membrane cycle, such that GTP-bound small GTPases carry out their functions at the periphery of endomembranes. A global understanding of the molecular determinants of the interaction of small GTPases with membranes and of the resulting supramolecular organization is beginning to emerge from studies of model systems. Recent studies highlighted that small GTPases establish multiple interactions with membranes involving their lipid anchor, their lipididated hypervariable region and elements in their GTPase domain, which combine to determine the strength, specificity and orientation of their association with lipids. Thereby, membrane association potentiates small GTPase interactions with GEFs, GAPs and effectors through colocalization and positional matching. Furthermore, it leads to small GTPase nanoclustering and to lipid demixing, which drives the assembly of molecular platforms in which proteins and lipids co-operate in producing high-fidelity signals through feedback and feedforward loops. Although still fragmentary, these observations point to an integrated model of signaling by membrane-attached small GTPases that involves a diversity of direct and indirect interactions, which can inspire new therapeutic strategies to block their activities in diseases.
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20
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Thomas LL, Joiner AMN, Fromme JC. The TRAPPIII complex activates the GTPase Ypt1 (Rab1) in the secretory pathway. J Cell Biol 2017; 217:283-298. [PMID: 29109089 PMCID: PMC5748984 DOI: 10.1083/jcb.201705214] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 09/01/2017] [Accepted: 10/03/2017] [Indexed: 12/30/2022] Open
Abstract
The TRAPP complexes are nucleotide exchange factors that activate Rab GTPases, and four different versions of TRAPP have been reported. Thomas et al. show that only two versions of TRAPP are detectable in normal cells and demonstrate that the TRAPPIII complex regulates Golgi trafficking in addition to its established role in autophagy. Rab GTPases serve as molecular switches to regulate eukaryotic membrane trafficking pathways. The transport protein particle (TRAPP) complexes activate Rab GTPases by catalyzing GDP/GTP nucleotide exchange. In mammalian cells, there are two distinct TRAPP complexes, yet in budding yeast, four distinct TRAPP complexes have been reported. The apparent differences between the compositions of yeast and mammalian TRAPP complexes have prevented a clear understanding of the specific functions of TRAPP complexes in all cell types. In this study, we demonstrate that akin to mammalian cells, wild-type yeast possess only two TRAPP complexes, TRAPPII and TRAPPIII. We find that TRAPPIII plays a major role in regulating Rab activation and trafficking at the Golgi in addition to its established role in autophagy. These disparate pathways share a common regulatory GTPase Ypt1 (Rab1) that is activated by TRAPPIII. Our findings lead to a simple yet comprehensive model for TRAPPIII function in both normal and starved eukaryotic cells.
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Affiliation(s)
- Laura L Thomas
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY
| | - Aaron M N Joiner
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY
| | - J Christopher Fromme
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY
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21
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Allosteric inhibition of the guanine nucleotide exchange factor DOCK5 by a small molecule. Sci Rep 2017; 7:14409. [PMID: 29089502 PMCID: PMC5663973 DOI: 10.1038/s41598-017-13619-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Accepted: 09/25/2017] [Indexed: 11/11/2022] Open
Abstract
Rac small GTPases and their GEFs of the DOCK family are pivotal checkpoints in development, autoimmunity and bone homeostasis, and their abnormal regulation is associated to diverse pathologies. Small molecules that inhibit their activities are therefore needed to investigate their functions. Here, we characterized the mechanism of inhibition of human DOCK5 by C21, a small molecule that inhibits mouse Dock5 in cells and blocks bone degradation in mice models of osteoporosis. We showed that the catalytic DHR2 domain of DOCK5 has a high basal GEF activity in the absence of membranes which is not regulated by a simple feedback loop. C21 blocks this activity in a non-competitive manner and is specific for DOCK5. In contrast, another Dock inhibitor, CPYPP, inhibits both DOCK5 and an unrelated GEF, Trio. To gain insight into structural features of the inhibitory mechanism of C21, we used SAXS analysis of DOCK5DHR2 and crystallographic analysis of unbound Rac1-GDP. Together, these data suggest that C21 takes advantage of intramolecular dynamics of DOCK5 and Rac1 to remodel the complex into an unproductive conformation. Based on this allosteric mechanism, we propose that diversion of intramolecular dynamics is a potent mechanism for the inhibition of multidomain regulators of small GTPases.
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22
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Benabdi S, Peurois F, Nawrotek A, Chikireddy J, Cañeque T, Yamori T, Shiina I, Ohashi Y, Dan S, Rodriguez R, Cherfils J, Zeghouf M. Family-wide Analysis of the Inhibition of Arf Guanine Nucleotide Exchange Factors with Small Molecules: Evidence of Unique Inhibitory Profiles. Biochemistry 2017; 56:5125-5133. [PMID: 28858527 DOI: 10.1021/acs.biochem.7b00706] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Arf GTPases and their guanine nucleotide exchange factors (ArfGEFs) are major regulators of membrane traffic and organelle structure in cells. They are associated with a variety of diseases and are thus attractive therapeutic targets for inhibition by small molecules. Several inhibitors of unrelated chemical structures have been discovered, which have shown their potential in dissecting molecular pathways and blocking disease-related functions. However, their specificity across the ArfGEF family has remained elusive. Importantly, inhibitory responses in the context of membranes, which are critical determinants of Arf and ArfGEF cellular functions, have not been investigated. Here, we compare the efficiency and specificity of four structurally distinct ArfGEF inhibitors, Brefeldin A, SecinH3, M-COPA, and NAV-2729, toward six ArfGEFs (human ARNO, EFA6, BIG1, and BRAG2 and Legionella and Rickettsia RalF). Inhibition was assessed by fluorescence kinetics using pure proteins, and its modulation by membranes was determined with lipidated GTPases in the presence of liposomes. Our analysis shows that despite the intra-ArfGEF family resemblance, each inhibitor has a specific inhibitory profile. Notably, M-COPA is a potent pan-ArfGEF inhibitor, and NAV-2729 inhibits all GEFs, the strongest effects being against BRAG2 and Arf1. Furthermore, the presence of the membrane-binding domain in Legionella RalF reveals a strong inhibitory effect of BFA that is not measured on its GEF domain alone. This study demonstrates the value of family-wide assays with incorporation of membranes, and it should enable accurate dissection of Arf pathways by these inhibitors to best guide their use and development as therapeutic agents.
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Affiliation(s)
- Sarah Benabdi
- Laboratoire de Biologie et Pharmacologie Appliquée CNRS, Ecole Normale Supérieure Paris-Saclay , 61 avenue du président Wilson, 94235 Cachan, France
| | - François Peurois
- Laboratoire de Biologie et Pharmacologie Appliquée CNRS, Ecole Normale Supérieure Paris-Saclay , 61 avenue du président Wilson, 94235 Cachan, France
| | - Agata Nawrotek
- Laboratoire de Biologie et Pharmacologie Appliquée CNRS, Ecole Normale Supérieure Paris-Saclay , 61 avenue du président Wilson, 94235 Cachan, France
| | - Jahnavi Chikireddy
- Laboratoire de Biologie et Pharmacologie Appliquée CNRS, Ecole Normale Supérieure Paris-Saclay , 61 avenue du président Wilson, 94235 Cachan, France
| | - Tatiana Cañeque
- Institut Curie, PSL Research University , Chemical Cell Biology group, 26 rue d'Ulm, 75248 Paris Cedex 05, France.,CNRS UMR3666 , 75005 Paris, France.,INSERM U1143 , 75005 Paris, France
| | - Takao Yamori
- Division of Molecular Pharmacology, Cancer Chemotherapy Center, Japanese Foundation for Cancer Research , Tokyo 135-8550, Japan
| | - Isamu Shiina
- Department of Applied Chemistry, Faculty of Science, Tokyo University of Science , Tokyo 162-8601, Japan
| | - Yoshimi Ohashi
- Division of Molecular Pharmacology, Cancer Chemotherapy Center, Japanese Foundation for Cancer Research , Tokyo 135-8550, Japan
| | - Shingo Dan
- Division of Molecular Pharmacology, Cancer Chemotherapy Center, Japanese Foundation for Cancer Research , Tokyo 135-8550, Japan
| | - Raphaël Rodriguez
- Institut Curie, PSL Research University , Chemical Cell Biology group, 26 rue d'Ulm, 75248 Paris Cedex 05, France.,CNRS UMR3666 , 75005 Paris, France.,INSERM U1143 , 75005 Paris, France
| | - Jacqueline Cherfils
- Laboratoire de Biologie et Pharmacologie Appliquée CNRS, Ecole Normale Supérieure Paris-Saclay , 61 avenue du président Wilson, 94235 Cachan, France
| | - Mahel Zeghouf
- Laboratoire de Biologie et Pharmacologie Appliquée CNRS, Ecole Normale Supérieure Paris-Saclay , 61 avenue du président Wilson, 94235 Cachan, France
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