title: Identification and characterization of a novel Rho GTPase activating protein implicated in receptor-mediated endocytosis.
abstract: Cbl-interacting protein of 85 kDa (CIN85) is a recently identified adaptor protein involved in the endocytic process of several receptor tyrosine kinases. Here we have identified a novel RhoGAP, CIN85 associated multi-domain containing Rho1 (CAMGAP1) as a binding protein for CIN85. CAMGAP1 is composed of an Src homology 3 (SH3) domain, multiple WW domains, a proline-rich region, a PH domain and a RhoGAP domain, and has the domain architecture similar to ARHGAP9 and ARHGAP12. CAMGAP1 mRNA is widely distributed in murine tissues. Biochemical assays showed its GAP activity toward Rac1 and Cdc42. Protein binding and expression studies indicated that the second SH3 domain of CIN85 binds to a proline-rich region of CAMGAP1. Overexpression of a truncated form of CAMGAP1 interferes with the internalization of transferrin receptors, suggesting that CAMGAP1 may play a role in clathrin-mediated endocytosis.
authors.affiliation: Department of Biochemistry, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi 980-8575, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Sakakibara
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Nemoto
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Nukiwa
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Takeshima
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D016466:CHO Cells; D019556:COS Cells; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D002522:Chlorocebus aethiops; D006224:Cricetinae; D003412:Cricetulus; D004705:Endocytosis; D004789:Enzyme Activation; D020690:GTPase-Activating Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D051379:Mice; D008969:Molecular Sequence Data; D011485:Protein Binding; D051381:Rats; D020794:Receptor Protein-Tyrosine Kinases / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D014168:Transferrin / Q000378:metabolism; D020764:cdc42 GTP-Binding Protein / Q000378:metabolism; D020830:rac1 GTP-Binding Protein / Q000378:metabolism; D018909:src Homology Domains
chemical_list: D002352:Carrier Proteins; D020690:GTPase-Activating Proteins; D011994:Recombinant Proteins; D014168:Transferrin; C085379:rho GTPase-activating protein; D020794:Receptor Protein-Tyrosine Kinases; D020764:cdc42 GTP-Binding Protein; D020830:rac1 GTP-Binding Protein