title: Role of Rab9 GTPase in facilitating receptor recruitment by TIP47.
abstract: Mannose 6-phosphate receptors (MPRs) deliver lysosomal hydrolases from the Golgi to endosomes and then return to the Golgi complex. TIP47 recognizes the cytoplasmic domains of MPRs and is required for endosome-to-Golgi transport. Here we show that TIP47 also bound directly to the Rab9 guanosine triphosphatase (GTPase) in its active, GTP-bound conformation. Moreover, Rab9 increased the affinity of TIP47 for its cargo. A functional Rab9 binding site was required for TIP47 stimulation of MPR transport in vivo. Thus, a cytosolic cargo selection device may be selectively recruited onto a specific organelle, and vesicle budding might be coupled to the presence of an active Rab GTPase.
authors.affiliation: Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305-5307, USA.
authors.forename: K S
authors.initials: KS
authors.lastname: Carroll
authors.forename: J
authors.initials: J
authors.lastname: Hanna
authors.forename: I
authors.initials: I
authors.lastname: Simon
authors.forename: J
authors.initials: J
authors.lastname: Krise
authors.forename: P
authors.initials: P
authors.lastname: Barbero
authors.forename: S R
authors.initials: SR
authors.lastname: Pfeffer
mesh_terms: D019943:Amino Acid Substitution / Q000235:genetics; D000818:Animals; D001665:Binding Sites; D002417:Cattle; D003593:Cytoplasm / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D011992:Endosomes / Q000378:metabolism; D006056:Golgi Apparatus / Q000378:metabolism; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins; D000070796:Perilipin-3; D011257:Pregnancy Proteins; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D017527:Receptor, IGF Type 2 / Q000737:chemistry / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D013379:Substrate Specificity; D033921:Vesicular Transport Proteins; D020691:rab GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D004268:DNA-Binding Proteins; D047908:Intracellular Signaling Peptides and Proteins; C038196:PLIN3 protein, human; D000070796:Perilipin-3; D011257:Pregnancy Proteins; D017527:Receptor, IGF Type 2; D011993:Recombinant Fusion Proteins; D033921:Vesicular Transport Proteins; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D020691:rab GTP-Binding Proteins