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Powis G, Meuillet EJ, Indarte M, Booher G, Kirkpatrick L. Pleckstrin Homology [PH] domain, structure, mechanism, and contribution to human disease. Biomed Pharmacother 2023; 165:115024. [PMID: 37399719 DOI: 10.1016/j.biopha.2023.115024] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Accepted: 06/14/2023] [Indexed: 07/05/2023] Open
Abstract
The pleckstrin homology [PH] domain is a structural fold found in more than 250 proteins making it the 11th most common domain in the human proteome. 25% of family members have more than one PH domain and some PH domains are split by one, or several other, protein domains although still folding to give functioning PH domains. We review mechanisms of PH domain activity, the role PH domain mutation plays in human disease including cancer, hyperproliferation, neurodegeneration, inflammation, and infection, and discuss pharmacotherapeutic approaches to regulate PH domain activity for the treatment of human disease. Almost half PH domain family members bind phosphatidylinositols [PIs] that attach the host protein to cell membranes where they interact with other membrane proteins to give signaling complexes or cytoskeleton scaffold platforms. A PH domain in its native state may fold over other protein domains thereby preventing substrate access to a catalytic site or binding with other proteins. The resulting autoinhibition can be released by PI binding to the PH domain, or by protein phosphorylation thus providing fine tuning of the cellular control of PH domain protein activity. For many years the PH domain was thought to be undruggable until high-resolution structures of human PH domains allowed structure-based design of novel inhibitors that selectively bind the PH domain. Allosteric inhibitors of the Akt1 PH domain have already been tested in cancer patients and for proteus syndrome, with several other PH domain inhibitors in preclinical development for treatment of other human diseases.
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Affiliation(s)
- Garth Powis
- PHusis Therapeutics Inc., 6019 Folsom Drive, La Jolla, CA 92037, USA.
| | | | - Martin Indarte
- PHusis Therapeutics Inc., 6019 Folsom Drive, La Jolla, CA 92037, USA
| | - Garrett Booher
- PHusis Therapeutics Inc., 6019 Folsom Drive, La Jolla, CA 92037, USA
| | - Lynn Kirkpatrick
- PHusis Therapeutics Inc., 6019 Folsom Drive, La Jolla, CA 92037, USA
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2
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Zhai Y, Chan WWR, Li W, Lau KF. ARNO is recruited by the neuronal adaptor FE65 to potentiate ARF6-mediated neurite outgrowth. Open Biol 2022; 12:220071. [PMID: 36168805 PMCID: PMC9516341 DOI: 10.1098/rsob.220071] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
ADP-ribosylation factor 6 (ARF6) is a small GTPase that has a variety of neuronal functions including stimulating neurite outgrowth, a crucial process for the establishment and maintenance of neural connectivity. As impaired and atrophic neurites are often observed in various brain injuries and neurological diseases, understanding the intrinsic pathways that stimulate neurite outgrowth may provide insights into developing strategies to trigger the reconnection of injured neurons. The neuronal adaptor FE65 has been shown to interact with ARF6 and potentiate ARF6-mediated neurite outgrowth. However, the precise mechanism that FE65 activates ARF6 remains unclear, as FE65 does not possess a guanine nucleotide exchange factor (GEF) domain/function. Here, we show that FE65 interacts with the ARF6 GEF, namely the ARF nucleotide-binding site opener (ARNO). Moreover, a complex consisting of ARNO, ARF6 and FE65 is detected. Notably, FE65 potentiates the stimulatory effect of ARNO on ARF6-mediated neurite outgrowth, and the effect of FE65 is abrogated by an FE65 mutation that disrupts FE65–ARNO interaction. Additionally, the intramolecular interaction for mediating the autoinhibited conformation of ARNO is attenuated by FE65. Moreover, FE65 potentiates the effects of wild-type ARNO, but not the monomeric mutant, suggesting an association between FE65 and ARNO dimerization. Collectively, we demonstrate that FE65 binds to and activates ARNO and, consequently, potentiates ARF6-mediated neurite outgrowth.
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Affiliation(s)
- Yuqi Zhai
- School of Life Sciences, Faculty of Science, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, People's Republic of China
| | - Wai Wa Ray Chan
- School of Life Sciences, Faculty of Science, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, People's Republic of China
| | - Wen Li
- School of Life Sciences, Faculty of Science, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, People's Republic of China.,Research Laboratory for Biomedical Optics and Molecular Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, People's Republic of China
| | - Kwok-Fai Lau
- School of Life Sciences, Faculty of Science, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, People's Republic of China
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3
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The PH Domain and C-Terminal polyD Motif of Phafin2 Exhibit a Unique Concurrence in Animals. MEMBRANES 2022; 12:membranes12070696. [PMID: 35877899 PMCID: PMC9324892 DOI: 10.3390/membranes12070696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 07/04/2022] [Accepted: 07/05/2022] [Indexed: 01/27/2023]
Abstract
Phafin2, a member of the Phafin family of proteins, contributes to a plethora of cellular activities including autophagy, endosomal cargo transportation, and macropinocytosis. The PH and FYVE domains of Phafin2 play key roles in membrane binding, whereas the C-terminal poly aspartic acid (polyD) motif specifically autoinhibits the PH domain binding to the membrane phosphatidylinositol 3-phosphate (PtdIns3P). Since the Phafin2 FYVE domain also binds PtdIns3P, the role of the polyD motif remains unclear. In this study, bioinformatics tools and resources were employed to determine the concurrence of the PH-FYVE module with the polyD motif among Phafin2 and PH-, FYVE-, or polyD-containing proteins from bacteria to humans. FYVE was found to be an ancient domain of Phafin2 and is related to proteins that are present in both prokaryotes and eukaryotes. Interestingly, the polyD motif only evolved in Phafin2 and PH- or both PH-FYVE-containing proteins in animals. PolyD motifs are absent in PH domain-free FYVE-containing proteins, which usually display cellular trafficking or autophagic functions. Moreover, the prediction of the Phafin2-interacting network indicates that Phafin2 primarily cross-talks with proteins involved in autophagy, protein trafficking, and neuronal function. Taken together, the concurrence of the polyD motif with the PH domain may be associated with complex cellular functions that evolved specifically in animals.
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4
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Ito A, Fukaya M, Okamoto H, Sakagami H. Physiological and Pathological Roles of the Cytohesin Family in Neurons. Int J Mol Sci 2022; 23:5087. [PMID: 35563476 PMCID: PMC9104363 DOI: 10.3390/ijms23095087] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2022] [Revised: 05/01/2022] [Accepted: 05/02/2022] [Indexed: 02/05/2023] Open
Abstract
The cytohesin proteins, consisting of four closely related members (cytohesins-1, -2, -3, and -4), are a subfamily of the Sec7 domain-containing guanine nucleotide exchange factors for ADP ribosylation factors (Arfs), which are critical regulators of membrane trafficking and actin cytoskeleton remodeling. Recent advances in molecular biological techniques and the development of a specific pharmacological inhibitor for cytohesins, SecinH3, have revealed the functional involvement of the cytohesin-Arf pathway in diverse neuronal functions from the formation of axons and dendrites, axonal pathfinding, and synaptic vesicle recycling, to pathophysiological processes including chronic pain and neurotoxicity induced by proteins related to neurodegenerative disorders, such as amyotrophic lateral sclerosis and Alzheimer's disease. Here, we review the physiological and pathological roles of the cytohesin-Arf pathway in neurons and discuss the future directions of this research field.
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Affiliation(s)
- Akiko Ito
- Department of Anesthesiology, Kitasato University School of Medicine, Sagamihara 252-0374, Kanagawa, Japan; (A.I.); (H.O.)
- Department of Anatomy, Kitasato University School of Medicine, Sagamihara 252-0374, Kanagawa, Japan;
| | - Masahiro Fukaya
- Department of Anatomy, Kitasato University School of Medicine, Sagamihara 252-0374, Kanagawa, Japan;
| | - Hirotsugu Okamoto
- Department of Anesthesiology, Kitasato University School of Medicine, Sagamihara 252-0374, Kanagawa, Japan; (A.I.); (H.O.)
| | - Hiroyuki Sakagami
- Department of Anatomy, Kitasato University School of Medicine, Sagamihara 252-0374, Kanagawa, Japan;
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5
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Li J, Lambright DG, Hsu VW. Coordination of Grp1 recruitment mechanisms by its phosphorylation. Mol Biol Cell 2020; 31:2816-2825. [PMID: 33026967 PMCID: PMC7851867 DOI: 10.1091/mbc.e20-03-0173] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The action of guanine nucleotide exchange factors (GEFs) on the ADP-ribosylation factor (ARF) family of small GTPases initiates intracellular transport pathways. This role requires ARF GEFs to be recruited from the cytosol to intracellular membrane compartments. An ARF GEF known as General receptor for 3-phosphoinositides 1 (Grp1) is recruited to the plasma membrane through its pleckstrin homology (PH) domain that recognizes phosphatidylinositol 3,4,5-trisphosphate (PIP3). Here, we find that the phosphorylation of Grp1 induces its PH domain to recognize instead phosphatidylinositol 4-phosphate (PI4P). This phosphorylation also releases an autoinhibitory mechanism that results in the coil–coil (CC) domain of Grp1 engaging two peripheral membrane proteins of the recycling endosome. Because the combination of these actions results in Grp1 being recruited preferentially to the recycling endosome rather than to the plasma membrane, our findings reveal the complexity of recruitment mechanisms that need to be coordinated in localizing an ARF GEF to an intracellular compartment to initiate a transport pathway. Our elucidation is also remarkable for having revealed that phosphoinositide recognition by a PH domain can be switched through its phosphorylation.
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Affiliation(s)
- Jian Li
- Division of Rheumatology, Inflammation and Immunity, Brigham and Women's Hospital and Department of Medicine, Harvard Medical School, Boston, MA 02115
| | - David G Lambright
- Program in Molecular Medicine, Department of Biochemistry and Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605
| | - Victor W Hsu
- Division of Rheumatology, Inflammation and Immunity, Brigham and Women's Hospital and Department of Medicine, Harvard Medical School, Boston, MA 02115
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Kim S, Kim H, Park D, Kim J, Hong J, Kim JS, Jung H, Kim D, Cheong E, Ko J, Um JW. Loss of IQSEC3 Disrupts GABAergic Synapse Maintenance and Decreases Somatostatin Expression in the Hippocampus. Cell Rep 2020; 30:1995-2005.e5. [PMID: 32049026 DOI: 10.1016/j.celrep.2020.01.053] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Revised: 12/28/2019] [Accepted: 01/16/2020] [Indexed: 12/31/2022] Open
Abstract
Gephyrin interacts with various GABAergic synaptic proteins to organize GABAergic synapse development. Among the multitude of gephyrin-binding proteins is IQSEC3, a recently identified component at GABAergic synapses that acts through its ADP ribosylation factor-guanine nucleotide exchange factor (ARF-GEF) activity to orchestrate GABAergic synapse formation. Here, we show that IQSEC3 knockdown (KD) reduced GABAergic synaptic density in vivo, suggesting that IQSEC3 is required for GABAergic synapse maintenance in vivo. We further show that IQSEC3 KD in the dentate gyrus (DG) increases seizure susceptibility and triggers selective depletion of somatostatin (SST) peptides in the DG hilus in an ARF-GEP activity-dependent manner. Strikingly, selective introduction of SST into SST interneurons in DG-specific IQSEC3-KD mice reverses GABAergic synaptic deficits. Thus, our data suggest that IQSEC3 is required for linking gephyrin-GABAA receptor complexes with ARF-dependent pathways to prevent aberrant, runaway excitation and thereby contributes to the integrity of SST interneurons and proper GABAergic synapse maintenance.
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Affiliation(s)
- Seungjoon Kim
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), 333 Techno Jungangdae-Ro, Hyeonpoong-Eup, Dalseong-Gun, Daegu 42988, Korea
| | - Hyeonho Kim
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), 333 Techno Jungangdae-Ro, Hyeonpoong-Eup, Dalseong-Gun, Daegu 42988, Korea
| | - Dongseok Park
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), 333 Techno Jungangdae-Ro, Hyeonpoong-Eup, Dalseong-Gun, Daegu 42988, Korea
| | - Jinhu Kim
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), 333 Techno Jungangdae-Ro, Hyeonpoong-Eup, Dalseong-Gun, Daegu 42988, Korea
| | - Joohyeon Hong
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul 03722, Korea
| | - Jae Seong Kim
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul 03722, Korea
| | - Hyeji Jung
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), 333 Techno Jungangdae-Ro, Hyeonpoong-Eup, Dalseong-Gun, Daegu 42988, Korea
| | - Dongwook Kim
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), 333 Techno Jungangdae-Ro, Hyeonpoong-Eup, Dalseong-Gun, Daegu 42988, Korea
| | - Eunji Cheong
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul 03722, Korea
| | - Jaewon Ko
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), 333 Techno Jungangdae-Ro, Hyeonpoong-Eup, Dalseong-Gun, Daegu 42988, Korea.
| | - Ji Won Um
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), 333 Techno Jungangdae-Ro, Hyeonpoong-Eup, Dalseong-Gun, Daegu 42988, Korea; Core Protein Resources Center, DGIST, 333 Techno Jungangdae-Ro, Hyeonpoong-Eup, Dalseong-Gun, Daegu 42988, Korea.
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7
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Zheng S, West JJ, Yu CG, Harris TJC. Arf-GEF localization and function at myosin-rich adherens junctions via coiled-coil heterodimerization with an adaptor protein. Mol Biol Cell 2019; 30:3090-3103. [PMID: 31693432 PMCID: PMC6938242 DOI: 10.1091/mbc.e19-10-0566] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Tissue dynamics require regulated interactions between adherens junctions and cytoskeletal networks. For example, myosin-rich adherens junctions recruit the cytohesin Arf-GEF Steppke, which down-regulates junctional tension and facilitates tissue stretching. We dissected this recruitment mechanism with structure–function and other analyses of Steppke and Stepping stone, an implicated adaptor protein. During Drosophila dorsal closure, Steppke’s coiled-coil domain was necessary and sufficient for junctional recruitment. Purified coiled-coil domains of Steppke and Stepping stone heterodimerized through a hydrophobic surface of the Steppke domain. This mapped surface was required for Steppke’s junctional localization and tissue regulation. Stepping stone colocalized with Steppke at junctions, and was required for junctional Steppke localization and proper tissue stretching. A second conserved region of Stepping stone was necessary and largely sufficient for junctional localization. Remarkably, this region could substitute for the Steppke coiled-coil domain for junction localization and regulation, suggesting the main role of the Steppke coiled-coil domain is linkage to the junctional targeting region of Stepping stone. Thus, coiled-coil heterodimerization with Stepping stone normally recruits Step to junctions. Intriguingly, Stepping stone’s junctional localization also seems partly dependent on Steppke.
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Affiliation(s)
- Shiyu Zheng
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S 3G5, Canada
| | - Junior J West
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S 3G5, Canada
| | - Cao Guo Yu
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S 3G5, Canada
| | - Tony J C Harris
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S 3G5, Canada
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8
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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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9
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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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10
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Ito A, Fukaya M, Saegusa S, Kobayashi E, Sugawara T, Hara Y, Yamauchi J, Okamoto H, Sakagami H. Pallidin is a novel interacting protein for cytohesin-2 and regulates the early endosomal pathway and dendritic formation in neurons. J Neurochem 2018; 147:153-177. [PMID: 30151872 DOI: 10.1111/jnc.14579] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 07/25/2018] [Accepted: 08/21/2018] [Indexed: 12/29/2022]
Abstract
Cytohesin-2 is a member of the guanine nucleotide exchange factors for ADP ribosylation factor 1 (Arf1) and Arf6, which are small GTPases that regulate membrane traffic and actin dynamics. In this study, we first demonstrated that cytohesin-2 localized to the plasma membrane and vesicles in various subcellular compartment in hippocampal neurons by immunoelectron microscopy. Next, to understand the molecular network of cytohesin-2 in neurons, we conducted yeast two-hybrid screening of brain cDNA libraries using cytohesin-2 as bait and isolated pallidin, a component of the biogenesis of lysosome-related organelles complex 1 (BLOC-1) involved in endosomal trafficking. Pallidin interacted specifically with cytohesin-2 among cytohesin family members. Glutathione S-transferase pull-down and immunoprecipitation assays further confirmed the formation of a protein complex between cytohesin-2 and pallidin. Immunofluorescence demonstrated that cytohesin-2 and pallidin partially colocalized in various subsets of endosomes immunopositive for EEA1, syntaxin 12, and LAMP2 in hippocampal neurons. Knockdown of pallidin or cytohesin-2 reduced cytoplasmic EEA1-positive early endosomes. Furthermore, knockdown of pallidin increased the total dendritic length of cultured hippocampal neurons, which was rescued by co-expression of wild-type pallidin but not a mutant lacking the ability to interact with cytohesin-2. In contrast, knockdown of cytohesin-2 had the opposite effect on total dendritic length. The present results suggested that the interaction between pallidin and cytohesin-2 may participate in various neuronal functions such as endosomal trafficking and dendritic formation in hippocampal neurons. Cover Image for this issue: doi: 10.1111/jnc.14197.
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Affiliation(s)
- Akiko Ito
- Department of Anatomy, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan.,Department of Anesthesiology, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan
| | - Masahiro Fukaya
- Department of Anatomy, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan
| | - Shintaro Saegusa
- Department of Anatomy, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan
| | - Emi Kobayashi
- Department of Anatomy, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan
| | - Takeyuki Sugawara
- Department of Anatomy, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan
| | - Yoshinobu Hara
- Department of Anatomy, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan
| | - Junji Yamauchi
- Laboratory of Molecular Neuroscience and Neurology, School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, Japan
| | - Hirotsugu Okamoto
- Department of Anesthesiology, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan
| | - Hiroyuki Sakagami
- Department of Anatomy, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan
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11
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Malaby AW, Das S, Chakravarthy S, Irving TC, Bilsel O, Lambright DG. Structural Dynamics Control Allosteric Activation of Cytohesin Family Arf GTPase Exchange Factors. Structure 2017; 26:106-117.e6. [PMID: 29276036 PMCID: PMC5752578 DOI: 10.1016/j.str.2017.11.019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2017] [Revised: 10/22/2017] [Accepted: 11/27/2017] [Indexed: 11/16/2022]
Abstract
Membrane dynamic processes including vesicle biogenesis depend on Arf
GTPase activation by guanine nucleotide exchange factors (GEFs) containing a
catalytic Sec7 domain and a membrane targeting module such as a PH domain. The
catalytic output of cytohesin family Arf GEFs is controlled by autoinhibitory
interactions that impede accessibility of the exchange site in the Sec7 domain.
These restraints can be relieved through activator Arf-GTP binding to an
allosteric site comprising the PH domain and proximal autoinhibitory elements
(Sec7-PH linker and C-terminal helix). Small angle X-ray scattering and
negative-stain electron microscopy were used to investigate the structural
organization and conformational dynamics of Cytohesin-3 (Grp1) in autoinhibited
and active states. The results support a model in which hinge dynamics in the
autoinhibited state expose the activator site for Arf-GTP binding, while
subsequent C-terminal helix unlatching and repositioning unleash conformational
entropy in the Sec7-PH linker to drive exposure of the exchange site.
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Affiliation(s)
- Andrew W Malaby
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA; Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Sanchaita Das
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Srinivas Chakravarthy
- The Biophysics Collaborative Access Team (BioCAT), Department of Biological Sciences, Illinois Institute of Technology, Chicago, IL 60616, USA
| | - Thomas C Irving
- The Biophysics Collaborative Access Team (BioCAT), Department of Biological Sciences, Illinois Institute of Technology, Chicago, IL 60616, USA
| | - Osman Bilsel
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - David G Lambright
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA; Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01655, USA.
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12
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Jun YW, Lee SH, Shim J, Lee JA, Lim CS, Kaang BK, Jang DJ. Dual roles of the N-terminal coiled-coil domain of anAplysiasec7 protein: homodimer formation and nuclear export. J Neurochem 2016; 139:1102-1112. [DOI: 10.1111/jnc.13875] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Revised: 09/13/2016] [Accepted: 10/12/2016] [Indexed: 12/24/2022]
Affiliation(s)
- Yong-Woo Jun
- Department of Ecological Science; College of Ecology and Environment; Kyungpook National University; Sangju-si Gyeongsangbuk-do Korea
| | - Seung-Hee Lee
- Department of Biological Sciences; Korea Institute of Science and Technology (KAIST); Daejeon Korea
| | - Jaehoon Shim
- Department of Biological Sciences; College of Natural Sciences; Seoul National University; Gwanak-gu Seoul Korea
| | - Jin-A Lee
- Department of Biotechnology and Biological Science; College of Life Science and Nano Technology; Hannam University; Yuseong-daero; Yuseong-gu Daejeon Korea
| | - Chae-Seok Lim
- Department of Biological Sciences; College of Natural Sciences; Seoul National University; Gwanak-gu Seoul Korea
| | - Bong-Kiun Kaang
- Department of Biological Sciences; College of Natural Sciences; Seoul National University; Gwanak-gu Seoul Korea
| | - Deok-Jin Jang
- Department of Ecological Science; College of Ecology and Environment; Kyungpook National University; Sangju-si Gyeongsangbuk-do Korea
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13
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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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14
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Roy NS, Yohe ME, Randazzo PA, Gruschus JM. Allosteric properties of PH domains in Arf regulatory proteins. CELLULAR LOGISTICS 2016; 6:e1181700. [PMID: 27294009 DOI: 10.1080/21592799.2016.1181700] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Revised: 04/13/2016] [Accepted: 04/14/2016] [Indexed: 10/21/2022]
Abstract
Pleckstrin Homology (PH) domains bind phospholipids and proteins. They are critical regulatory elements of a number enzymes including guanine nucleotide exchange factors (GEFs) and GTPase-activating proteins (GAPs) for Ras-superfamily guanine nucleotide binding proteins such as ADP-ribosylation factors (Arfs). Recent studies have indicated that many PH domains may bind more than one ligand cooperatively. Here we discuss the molecular basis of PH domain-dependent allosteric behavior of 2 ADP-ribosylation factor exchange factors, Grp1 and Brag2, cooperative binding of ligands to the PH domains of Grp1 and the Arf GTPase-activating protein, ASAP1, and the consequences for activity of the associated catalytic domains.
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Affiliation(s)
- Neeladri Sekhar Roy
- Laboratory of Cellular and Molecular Biology, National Cancer Institute, National Institutes of Health , Bethesda, MD, USA
| | - Marielle E Yohe
- Genetics Branch, National Cancer Institute, National Institutes of Health , Bethesda, MD, USA
| | - Paul A Randazzo
- Laboratory of Cellular and Molecular Biology, National Cancer Institute, National Institutes of Health , Bethesda, MD, USA
| | - James M Gruschus
- Laboratory of Structural Biophysics, National Heart, Lung and Blood Institute, National Institutes of Health , Bethesda, MD, USA
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15
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Um JW, Choii G, Park D, Kim D, Jeon S, Kang H, Mori T, Papadopoulos T, Yoo T, Lee Y, Kim E, Tabuchi K, Ko J. IQ Motif and SEC7 Domain-containing Protein 3 (IQSEC3) Interacts with Gephyrin to Promote Inhibitory Synapse Formation. J Biol Chem 2016; 291:10119-30. [PMID: 27002143 DOI: 10.1074/jbc.m115.712893] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2015] [Indexed: 01/13/2023] Open
Abstract
Gephyrin is a central scaffold protein that mediates development, function, and plasticity of mammalian inhibitory synapses by interacting with various inhibitory synaptic proteins. Here, we show that IQSEC3, a guanine nucleotide exchange factor for ARF6, directly interacts with gephyrin, an interaction that is critical for the inhibitory synapse localization of IQSEC3. Overexpression of IQSEC3 increases inhibitory, but not excitatory, synapse density in a guanine nucleotide exchange factor activity-dependent manner. Conversely, knockdown of IQSEC3 decreases size of gephyrin cluster without altering gephyrin puncta density. Collectively, these data reveal that IQSEC3 acts together with gephyrin to regulate inhibitory synapse development.
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Affiliation(s)
- Ji Won Um
- From the Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Republic of Korea, the Department of Physiology and BK21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul 120-752, Republic of Korea
| | - Gayoung Choii
- From the Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Republic of Korea
| | - Dongseok Park
- the Department of Physiology and BK21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul 120-752, Republic of Korea
| | - Dongwook Kim
- the Department of Physiology and BK21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul 120-752, Republic of Korea
| | - Sangmin Jeon
- From the Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Republic of Korea
| | - Hyeyeon Kang
- the Department of Physiology and BK21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul 120-752, Republic of Korea
| | - Takuma Mori
- the Shinshu University School of Medicine, Matsumoto 390-8621, Japan
| | - Theofilos Papadopoulos
- the Department of Molecular Biology, University Medicine Göttingen, Göttingen 37075, Germany
| | - Taesun Yoo
- the Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Republic of Korea
| | - Yeunkum Lee
- the Center for Synaptic Brain Dysfunctions, Institute for Basic Science, Daejeon 305-701, Republic of Korea, and
| | - Eunjoon Kim
- the Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Republic of Korea, the Center for Synaptic Brain Dysfunctions, Institute for Basic Science, Daejeon 305-701, Republic of Korea, and
| | - Katsuhiko Tabuchi
- the Shinshu University School of Medicine, Matsumoto 390-8621, Japan, PRESTO, Japan Science and Technology Agency, Kawaguchi 332-0012, Japan
| | - Jaewon Ko
- From the Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Republic of Korea,
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16
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Lee DM, Rodrigues FF, Yu CG, Swan M, Harris TJC. PH Domain-Arf G Protein Interactions Localize the Arf-GEF Steppke for Cleavage Furrow Regulation in Drosophila. PLoS One 2015; 10:e0142562. [PMID: 26556630 PMCID: PMC4640550 DOI: 10.1371/journal.pone.0142562] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Accepted: 10/23/2015] [Indexed: 11/18/2022] Open
Abstract
The recruitment of GDP/GTP exchange factors (GEFs) to specific subcellular sites dictates where they activate small G proteins for the regulation of various cellular processes. Cytohesins are a conserved family of plasma membrane GEFs for Arf small G proteins that regulate endocytosis. Analyses of mammalian cytohesins have identified a number of recruitment mechanisms for these multi-domain proteins, but the conservation and developmental roles for these mechanisms are unclear. Here, we report how the pleckstrin homology (PH) domain of the Drosophila cytohesin Steppke affects its localization and activity at cleavage furrows of the early embryo. We found that the PH domain is necessary for Steppke furrow localization, and for it to regulate furrow structure. However, the PH domain was not sufficient for the localization. Next, we examined the role of conserved PH domain amino acid residues that are required for mammalian cytohesins to bind PIP3 or GTP-bound Arf G proteins. We confirmed that the Steppke PH domain preferentially binds PIP3 in vitro through a conserved mechanism. However, disruption of residues for PIP3 binding had no apparent effect on GFP-Steppke localization and effects. Rather, residues for binding to GTP-bound Arf G proteins made major contributions to this Steppke localization and activity. By analyzing GFP-tagged Arf and Arf-like small G proteins, we found that Arf1-GFP, Arf6-GFP and Arl4-GFP, but not Arf4-GFP, localized to furrows. However, analyses of embryos depleted of Arf1, Arf6 or Arl4 revealed either earlier defects than occur in embryos depleted of Steppke, or no detectable furrow defects, possibly because of redundancies, and thus it was difficult to assess how individual Arf small G proteins affect Steppke. Nonetheless, our data show that the Steppke PH domain and its conserved residues for binding to GTP-bound Arf G proteins have substantial effects on Steppke localization and activity in early Drosophila embryos.
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Affiliation(s)
- Donghoon M. Lee
- Department of Cell & Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | | | - Cao Guo Yu
- Department of Cell & Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Michael Swan
- Department of Cell & Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Tony J. C. Harris
- Department of Cell & Systems Biology, University of Toronto, Toronto, Ontario, Canada
- * E-mail:
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17
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Salem JC, Reviriego-Mendoza MM, Santy LC. ARF-GEF cytohesin-2/ARNO regulates R-Ras and α5-integrin recycling through an EHD1-positive compartment. Mol Biol Cell 2015; 26:4265-79. [PMID: 26378252 PMCID: PMC4642859 DOI: 10.1091/mbc.e15-05-0278] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Accepted: 09/11/2015] [Indexed: 11/30/2022] Open
Abstract
R-Ras and cytohesin-2/ARNO coordinate in the control of epithelial cell adhesion, but the mechanism has been unclear. Cytohesin-2/ARNO regulates traffic through an EHD1-positive recycling compartment. Inhibition of cytohesin-2/ARNO activity traps R-Ras and integrins within the EHD1 compartment and impairs adhesion and spreading. When expressed in epithelial cells, cytohesin-2/ARNO, a guanine nucleotide exchange factor (GEF) for ARF small GTPases, causes a robust migration response. Recent evidence suggests that cytohesin-2/ARNO acts downstream of small the GTPase R-Ras to promote spreading and migration. We hypothesized that cytohesin-2/ARNO could transmit R-Ras signals by regulating the recycling of R-Ras through ARF activation. We found that Eps15-homology domain 1 (EHD1), a protein that associates with the endocytic recycling compartment (ERC), colocalizes with active R-Ras in transiently expressed HeLa cells. In addition, we show that EHD1-positive recycling endosomes are a novel compartment for cytohesin-2/ARNO. Knockdown or expression of GEF-inactive (E156K) cytohesin-2/ARNO causes R-Ras to accumulate on recycling endosomes containing EHD1 and inhibits cell spreading. E156K-ARNO also causes a reduction in focal adhesion size and number. Finally, we demonstrate that R-Ras/ARNO signaling is required for recycling of α5-integrin and R-Ras to the plasma membrane. These data establish a role for cytohesin-2/ARNO as a regulator of R-Ras and integrin recycling and suggest that ARF-regulated trafficking of R-Ras is required for R-Ras–dependent effects on spreading and adhesion formation.
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Affiliation(s)
- Joseph C Salem
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA 16802
| | - Marta M Reviriego-Mendoza
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA 16802
| | - Lorraine C Santy
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA 16802
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18
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Lee S, Wurtzel JGT, Goldfinger LE. The RLIP76 N-terminus binds ARNO to regulate PI 3-kinase, Arf6 and Rac signaling, cell spreading and migration. Biochem Biophys Res Commun 2014; 454:560-5. [PMID: 25450693 DOI: 10.1016/j.bbrc.2014.10.114] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Accepted: 10/24/2014] [Indexed: 11/29/2022]
Abstract
RLIP76 is a multifunctional protein involved in tumor growth and angiogenesis, and a promising therapeutic target in many cancers. RLIP76 harbors docking sites for many proteins, and we have found that it interacts with ARNO, a guanine nucleotide exchange factor for Arf6, and that RLIP76 regulates activation of Rac1 via Arf6, and regulates cell spreading and migration in an ARNO and Arf6-dependent manner. Here we show that ARNO interacts with the RLIP76 N-terminal domain, and this domain was required for RLIP76-dependent cell spreading and migration. We identified two sites in the RLIP76 N-terminus with differential effects on ARNO binding and downstream signaling: Ser29/Ser30 and Ser62. Ser29/30 mutation to Alanine inhibited ARNO interaction and was sufficient to block RLIP76-dependent cell spreading and migration, as well as RLIP76-dependent Arf6 activation. In contrast, RLIP76(S62A) interacted with ARNO and supported Arf6 activation. However, both sets of mutations blocked Rac1 activation. RLIP76-mediated Rac and Arf6 activation required PI3K activity. S29/30A mutations inhibited RLIP76-dependent PI3K activation, but S62A mutation did not. Together these results show that ARNO interaction with the RLIP76 N-terminus regulates cell spreading and motility via PI3K and Arf6, independent of RLIP76 control of Rac.
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Affiliation(s)
- Seunghyung Lee
- Department of Anatomy & Cell Biology and The Sol Sherry Thrombosis Research Center, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | - Jeremy G T Wurtzel
- Department of Anatomy & Cell Biology and The Sol Sherry Thrombosis Research Center, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | - Lawrence E Goldfinger
- Department of Anatomy & Cell Biology and The Sol Sherry Thrombosis Research Center, Temple University School of Medicine, Philadelphia, PA 19140, USA; Cancer Biology Program, Fox Chase Cancer Center, Philadelphia, PA 19111, USA.
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