title: Rab11BP/Rabphilin-11, a downstream target of rab11 small G protein implicated in vesicle recycling.
abstract: Rab11 small G protein has been implicated in vesicle recycling, but its upstream regulators or downstream targets have not yet been identified. We isolated here a downstream target of Rab11, named rabphilin-11, from bovine brain. Moreover, we isolated from a rat brain cDNA library its cDNA, which encoded a protein with a M(r) of 100,946 and 908 amino acids (aa). Rabphilin-11 bound GTP-Rab11 more preferentially than GDP-Rab11 at the N-terminal region and was specific for Rab11 and inactive for other Rab and Rho small G proteins. Both GTP-Rab11 and rabphilin-11 were colocalized at perinuclear regions, presumably the Golgi complex and recycling endosomes, in Madin-Darby canine kidney cells. In HeLa cells cultured on fibronectin, both the proteins were localized not only at perinuclear regions but also along microtubules, which were oriented toward membrane lamellipodia. Treatment of HeLa cells with nocodazole caused disruption of microtubules and dispersion of GTP-Rab11 and rabphilin-11. Overexpression of the C-terminal fragment of rabphilin-11 (aa 607-730), lacking the GTP-Rab11 binding domain, in HeLa cells reduced accumulation of transferrin at perinuclear regions and cell migration. Rabphilin-11 turned out to be a rat counterpart of recently reported bovine Rab11BP. These results indicate that rabphilin-11 is a downstream target of Rab11 which is involved in vesicle recycling.
authors.affiliation: Department of Molecular Biology and Biochemistry, Osaka University Medical School, Suita 565-0871, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Mammoto
authors.forename: T
authors.initials: T
authors.lastname: Ohtsuka
authors.forename: I
authors.initials: I
authors.lastname: Hotta
authors.forename: T
authors.initials: T
authors.lastname: Sasaki
authors.forename: Y
authors.initials: Y
authors.lastname: Takai
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology; D001692:Biological Transport; D002417:Cattle; D003594:Cytoplasmic Granules / Q000378:metabolism* / Q000648:ultrastructure; D004285:Dogs; D019204:GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D008870:Microtubules / Q000378:metabolism*; D008969:Molecular Sequence Data; D015739:Nocodazole / Q000494:pharmacology; D051381:Rats; D020691:rab GTP-Binding Proteins; D000099193:rab11 GTP-Binding Proteins
chemical_list: D000970:Antineoplastic Agents; D019204:GTP-Binding Proteins; D015739:Nocodazole; D020691:rab GTP-Binding Proteins; D000099193:rab11 GTP-Binding Proteins; C492252:Wdr44 protein, rat; C118779:rab11 binding protein, Bos taurus