title: Role of Erv29p in collecting soluble secretory proteins into ER-derived transport vesicles.
abstract: Proteins are transported from the endoplasmic reticulum (ER) in vesicles formed by coat protein complex II (COPII). Soluble secretory proteins are thought to leave the ER in these vesicles by "bulk flow" or through recognition by hypothetical shuttling receptors. We found that Erv29p, a conserved transmembrane protein, was directly required for packaging glycosylated pro-alpha-factor (gpalphaf) into COPII vesicles in Saccharomyces cerevisiae. Further, an Erv29p-gpalphaf complex was isolated from ER-derived transport vesicles. In vivo, export of gpalphaf from the ER was saturable and depended on the expression level of Erv29p. These results indicate that membrane receptors can link soluble cargo proteins to the COPII coat.
authors.affiliation: Department of Biochemistry, Dartmouth Medical School, Hanover, NH 03755, USA.
authors.forename: W J
authors.initials: WJ
authors.lastname: Belden
authors.forename: C
authors.initials: C
authors.lastname: Barlowe
mesh_terms: D022181:COP-Coated Vesicles / Q000378:metabolism*; D002268:Carboxypeptidases / Q000378:metabolism; D043402:Cathepsin A; D003432:Cross-Linking Reagents; D019281:Dimerization; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D006031:Glycosylation; D006056:Golgi Apparatus / Q000378:metabolism; D007700:Kinetics; D000072235:Mating Factor; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D026901:Membrane Transport Proteins; D010455:Peptides / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D011233:Precipitin Tests; D017510:Protein Folding; D011498:Protein Precursors / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D021381:Protein Transport; D050766:Qb-SNARE Proteins; D000069816:SEC Translocation Channels; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D029701:Saccharomyces cerevisiae Proteins; D012995:Solubility; D013388:Succinimides / Q000494:pharmacology; D033921:Vesicular Transport Proteins
chemical_list: C068037:BOS1 protein, S cerevisiae; D003432:Cross-Linking Reagents; C432391:Erv29 protein, S cerevisiae; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D010455:Peptides; D011498:Protein Precursors; D050766:Qb-SNARE Proteins; D000069816:SEC Translocation Channels; C499383:SEC61 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D013388:Succinimides; D033921:Vesicular Transport Proteins; D000072235:Mating Factor; D002268:Carboxypeptidases; D043402:Cathepsin A; C011240:dithiobis(succinimidylpropionate)