start-ver=1.4 cd-journal=joma no-vol=20 cd-vols= no-issue=19 article-no= start-page=4205 end-page=4215 dt-received= dt-revised= dt-accepted= dt-pub-year=2009 dt-pub=20091001 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=mTrs130 Is a Component of a Mammalian TRAPPII Complex, a Rab1 GEF That Binds to COPI-coated Vesicles en-subtitle= kn-subtitle= en-abstract= kn-abstract=The GTPase Rab1 regulates endoplasmic reticulum-Golgi and early Golgi traffic. The guanine nucleotide exchange factor (GEF) or factors that activate Rab1 at these stages of the secretory pathway are currently unknown. Trs130p is a subunit of the yeast TRAPPII (transport protein particle II) complex, a multisubunit tethering complex that is a GEF for the Rab1 homologue Ypt1p. Here, we show that mammalian Trs130 (mTrs130) is a component of an analogous TRAPP complex in mammalian cells, and we describe for the first time the role that this complex plays in membrane traffic. mTRAPPII is enriched on COPI (Coat Protein I)-coated vesicles and buds, but not Golgi cisternae, and it specifically activates Rab1. In addition, we find that mTRAPPII binds to ƒÁ1COP, a COPI coat adaptor subunit. The depletion of mTrs130 by short hairpin RNA leads to an increase of vesicles in the vicinity of the Golgi and the accumulation of cargo in an early Golgi compartment. We propose that mTRAPPII is a Rab1 GEF that tethers COPI-coated vesicles to early Golgi membranes. en-copyright= kn-copyright= en-aut-name=YamasakiAkinori en-aut-sei=Yamasaki en-aut-mei=Akinori kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=MenonShekar en-aut-sei=Menon en-aut-mei=Shekar kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=YuSidney en-aut-sei=Yu en-aut-mei=Sidney kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=BarrowmanJemima en-aut-sei=Barrowman en-aut-mei=Jemima kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=MeerlooTimo en-aut-sei=Meerloo en-aut-mei=Timo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=OorschotViola en-aut-sei=Oorschot en-aut-mei=Viola kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=KlumpermanJudith en-aut-sei=Klumperman en-aut-mei=Judith kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=SatohAyano en-aut-sei=Satoh en-aut-mei=Ayano kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 ORCID= en-aut-name=Ferro-NovickSusan en-aut-sei=Ferro-Novick en-aut-mei=Susan kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=9 ORCID= affil-num=1 en-affil= kn-affil=Department of Cell Biology, Howard Hughes Medical Institute, Yale University School of Medicine affil-num=2 en-affil= kn-affil=Department of Cell Biology, Howard Hughes Medical Institute, Yale University School of Medicine affil-num=3 en-affil= kn-affil=Department of Cell Biology, Howard Hughes Medical Institute, Yale University School of Medicine affil-num=4 en-affil= kn-affil=Department of Cell Biology, Howard Hughes Medical Institute, Yale University School of Medicine affil-num=5 en-affil= kn-affil=Department of Cellular and Molecular Medicine, University of California at San Diego affil-num=6 en-affil= kn-affil=Cell Microscopy Center, Department of Cell Biology, University Medical Center Utrecht affil-num=7 en-affil= kn-affil=Cell Microscopy Center, Department of Cell Biology, University Medical Center Utrecht affil-num=8 en-affil= kn-affil=Department of Cell Biology, Yale University School of Medicine affil-num=9 en-affil= kn-affil=Department of Cell Biology, Howard Hughes Medical Institute, Yale University School of Medicine END