title: Dsl1p, Tip20p, and the novel Dsl3(Sec39) protein are required for the stability of the Q/t-SNARE complex at the endoplasmic reticulum in yeast.
abstract: The "Dsl1p complex" in Saccharomyces cerevisiae, consisting of Dsl1p and Tip20p, is involved in Golgi-ER retrograde transport and it is functionally conserved from yeast to mammalian cells. To further characterize this complex, we analyzed the function of Dsl3p, a protein that interacts with Dsl1p in yeast two hybrids screens. DSL3, recently identified in a genome wide analysis of essential genes as SEC39, encodes a cytosolic protein of 82 kDa that is peripherally associated with membranes derived from the ER. There is strong genetic interaction between DSL3 and other factors required for Golgi-ER retrograde transport. Size exclusion chromatography and affinity purification approaches confirmed that Dsl3p is associated with subunits of the "Dsl1p complex." The complex also includes the Q/t-SNARE proteins, Use1p, Sec20p, and Ufe1p, integral membrane proteins that constitute the trimeric acceptor for R/v-SNAREs on Golgi-derived vesicles at the ER. Using mutants, we performed a detailed analysis of interactions between subunits of the Dsl1p complex and the ER-localized SNARE proteins. This analysis showed that both Dsl1p and Dsl3p are required for the stable interaction of the SNARE Use1p with a central subcomplex consisting of Tip20p and the SNARE proteins Ufe1p and Sec20p.
authors.affiliation: Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA.
authors.forename: Bryan A
authors.initials: BA
authors.lastname: Kraynack
authors.forename: Angela
authors.initials: A
authors.lastname: Chan
authors.forename: Eva
authors.initials: E
authors.lastname: Rosenthal
authors.forename: Miriam
authors.initials: M
authors.lastname: Essid
authors.forename: Barbara
authors.initials: B
authors.lastname: Umansky
authors.forename: M Gerard
authors.initials: MG
authors.lastname: Waters
authors.forename: Hans Dieter
authors.initials: HD
authors.lastname: Schmitt
mesh_terms: D002352:Carrier Proteins / Q000502:physiology*; D004721:Endoplasmic Reticulum / Q000502:physiology; D006023:Glycoproteins / Q000502:physiology*; D008565:Membrane Proteins / Q000235:genetics / Q000502:physiology*; D009154:Mutation; D016133:Polymerase Chain Reaction; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology*; D033921:Vesicular Transport Proteins
chemical_list: D002352:Carrier Proteins; C428365:DSL1 protein, S cerevisiae; D006023:Glycoproteins; D008565:Membrane Proteins; C506557:SEC39 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C489479:TIP20 protein, S cerevisiae; D033921:Vesicular Transport Proteins