title: Identification of the novel TRAPP associated protein Tca17.
abstract: Vesicle tethers are long coiled-coil proteins or multisubunit complexes that provide specificity to the membrane fusion process by linking cargo-containing vesicles to target membranes. Transport protein particle (TRAPP) is a well-characterized multisubunit tethering complex that acts as a GTP exchange factor and is present in two cellular forms: a 7 subunit TRAPP I complex required for ER-to-Golgi transport, and a 10 subunit TRAPP II complex that mediates post-Golgi trafficking. In this work, we have identified Tca17, which is encoded by the non-essential ORF YEL048c, as a novel binding partner of the TRAPP complex. Loss of Tca17 or any of the non-essential TRAPP subunits (Trs33, Trs65 and Trs85) leads to defects in the Golgi-endosomal recycling of Snc1. We show that Tca17, a Sedlin_N family member similar to the TRAPP subunit Trs20, interacts with the TRAPP complex in a Trs33- and Trs65-dependent manner. Mutation of TCA17 or TRS33 perturbs the association of Trs65 with the rest of the TRAPP complex and alters the localization of the Rab GTPase Ypt31. These data support a model in which Tca17 acts with Trs33 and Trs65 to promote the assembly and/or stability of the TRAPP complex and regulate its activity in post-Golgi trafficking events.
authors.affiliation: Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, Department of Medical Genetics, University of British Columbia, Vancouver, BC V5Z 4H4, Canada.
authors.forename: Ben
authors.initials: B
authors.lastname: Montpetit
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Conibear
mesh_terms: D000595:Amino Acid Sequence; D006056:Golgi Apparatus / Q000378:metabolism; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D009154:Mutation; D011485:Protein Binding; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D033921:Vesicular Transport Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D029701:Saccharomyces cerevisiae Proteins; C000593022:Tca17 protein, S cerevisiae; D033921:Vesicular Transport Proteins; C406327:transport protein particle, TRAPP