title: GRASP and IPCEF promote ARF-to-Rac signaling and cell migration by coordinating the association of ARNO/cytohesin 2 with Dock180.
abstract: ARFs are small GTPases that regulate vesicular trafficking, cell shape, and movement. ARFs are subject to extensive regulation by a large number of accessory proteins. The many different accessory proteins are likely specialized to regulate ARF signaling during particular processes. ARNO/cytohesin 2 is an ARF-activating protein that promotes cell migration and cell shape changes. We report here that protein-protein interactions mediated by the coiled-coil domain of ARNO are required for ARNO induced motility. ARNO lacking the coiled-coil domain does not promote migration and does not induce ARF-dependent Rac activation. We find that the coiled-coil domain promotes the assembly of a multiprotein complex containing both ARNO and the Rac-activating protein Dock180. Knockdown of either GRASP/Tamalin or IPCEF, two proteins known to bind to the coiled-coil of ARNO, prevents the association of ARNO and Dock180 and prevents ARNO-induced Rac activation. These data suggest that scaffold proteins can regulate ARF dependent processes by biasing ARF signaling toward particular outputs.
authors.affiliation: Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA 16802, USA.
authors.forename: David T
authors.initials: DT
authors.lastname: White
authors.forename: Katie M
authors.initials: KM
authors.lastname: McShea
authors.forename: Myriam A
authors.initials: MA
authors.lastname: Attar
authors.forename: Lorraine C
authors.initials: LC
authors.lastname: Santy
mesh_terms: D020727:ADP-Ribosylation Factors / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D015815:Cell Adhesion Molecules / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D002465:Cell Movement / Q000502:physiology*; D004285:Dogs; D004789:Enzyme Activation; D020690:GTPase-Activating Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D055785:Gene Knockdown Techniques; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D046912:Multiprotein Complexes / Q000737:chemistry / Q000378:metabolism; D017433:Protein Structure, Secondary; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*; D020744:rac GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D047908:Intracellular Signaling Peptides and Proteins
chemical_list: D020727:ADP-Ribosylation Factors; D002352:Carrier Proteins; D015815:Cell Adhesion Molecules; D020690:GTPase-Activating Proteins; D008565:Membrane Proteins; D046912:Multiprotein Complexes; D034741:RNA, Small Interfering; D020744:rac GTP-Binding Proteins; C099818:DOCK1 protein, human; C550843:IPCEF1 protein, human; D047908:Intracellular Signaling Peptides and Proteins; C102474:cytohesin-2; C410230:tamalin protein, human