title: A link between ER tethering and COP-I vesicle uncoating.
abstract: The yeast Dsl1p vesicle tethering complex, comprising the three subunits Dsl1p, Dsl3p, and Tip20p, is stably associated with three endoplasmic reticulum-localized Q-SNAREs and is believed to play a central role in the tethering and fusion of Golgi-derived COP-I transport vesicles. Dsl1p also interacts directly with COP-I subunits. We now show that binding of Dsl1p to COP-I subunits involves binding sites identical to those involved in interactions between COP-I subunits that stabilize the COP-I coat. Cells with defects in Dsl/SNARE complex function show massive accumulation of COP-I-coated vesicles in a cluster to which COP-II coat proteins are also recruited. Our results suggest that binding of Dsl/SNARE complex to the COP-I coat complex serves two functions: to mediate vesicle tethering and to assist the uncoating process by blocking domains in COP-I that drive repolymerization and the formation of large COP-I aggregates.
authors.affiliation: Department Neurobiology, Max Planck Institute for Biophysical Chemistry, Göttingen, D37077, Germany.
authors.forename: Sabrina
authors.initials: S
authors.lastname: Zink
authors.forename: Dirk
authors.initials: D
authors.lastname: Wenzel
authors.forename: Christian A
authors.initials: CA
authors.lastname: Wurm
authors.forename: Hans Dieter
authors.initials: HD
authors.lastname: Schmitt
mesh_terms: D001665:Binding Sites; D020755:Coat Protein Complex I / Q000378:metabolism*; D015536:Down-Regulation; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D005982:Glutathione Transferase / Q000378:metabolism; D018613:Microscopy, Confocal / Q000379:methods; D008856:Microscopy, Fluorescence / Q000379:methods; D008954:Models, Biological; D008957:Models, Genetic; D009154:Mutation; D010641:Phenotype; D010957:Plasmids / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*
chemical_list: D020755:Coat Protein Complex I; C428365:DSL1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D005982:Glutathione Transferase