title: Vps4-A (vacuolar protein sorting 4-A) is a binding partner for a novel Rho family GTPase, Rnd2.
abstract: Rho family GTPases are implicated in a variety of biological activities, including endocytic vesicle trafficking. Rnd2 is a new member of Rho family GTPases, but its biological functions are not known. In the present study, we have performed a yeast two-hybrid screening using Rnd2 as bait and revealed that Rnd2 binds specifically to Vps4-A (where Vsp4-A is vacuolar protein sorting 4-A), a member of the AAA ATPase family and a central regulator for early endosome trafficking. This interaction was determined by the yeast two-hybrid system, in vitro binding and co-immunoprecipitation studies. Vps4-A associated with both guanosine 5'-[beta-thio]triphosphate-bound active and guanosine 5'-[beta-thio]diphosphate-bound inactive forms of Rnd2. An ATPase-defective Vps4-A mutant, Vps4-A(E228Q), expressed in HeLa cells was accumulated in the early endosomes. When Rnd2 was co-expressed with Vps4-A(E228Q), Rnd2 was recruited to the Vps4-A-bound early endosomes. These results suggest that Rnd2 is involved in the regulation of endosomal trafficking via direct binding to Vps4-A.
authors.affiliation: Laboratory of Molecular Neurobiology, Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan.
authors.forename: Hiroko
authors.initials: H
authors.lastname: Tanaka
authors.forename: Hirotada
authors.initials: H
authors.lastname: Fujita
authors.forename: Hironori
authors.initials: H
authors.lastname: Katoh
authors.forename: Kazutoshi
authors.initials: K
authors.lastname: Mori
authors.forename: Manabu
authors.initials: M
authors.lastname: Negishi
mesh_terms: D000818:Animals; D011992:Endosomes / Q000378:metabolism; D005656:Fungal Proteins / Q000378:metabolism*; D019204:GTP-Binding Proteins / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D021381:Protein Transport; D051381:Rats; D011956:Receptors, Cell Surface / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D020798:Two-Hybrid System Techniques; D033921:Vesicular Transport Proteins
chemical_list: D005656:Fungal Proteins; C087335:PEP1 protein, S cerevisiae; D011956:Receptors, Cell Surface; D029701:Saccharomyces cerevisiae Proteins; D033921:Vesicular Transport Proteins; D019204:GTP-Binding Proteins