The coatomer-interacting protein Dsl1p is required for Golgi-to-endoplasmic reticulum retrieval in yeast.
Sec22p is an endoplasmic reticulum (ER)-Golgi v-SNARE protein whose retrieval from the Golgi compartment to the endoplasmic reticulum (ER) is mediated by COPI vesicles. Whether Sec22p exhibits its primary role at the ER or the Golgi apparatus is still a matter of debate. To determine the role of Sec22p in intracellular transport more precisely, we performed a synthetic lethality screen. We isolated mutant yeast strains in which SEC22 gene function, which in a wild type strain background is non-essential for cell viability, has become essential. In this way a novel temperature-sensitive mutant allele, dsl1-22, of the essential gene DSL1 was obtained. The dsl1-22 mutation causes severe defects in Golgi-to-ER retrieval of ER-resident SNARE proteins and integral membrane proteins harboring a C-terminal KKXX retrieval motif, as well as of the soluble ER protein BiP/Kar2p, which utilizes the HDEL receptor, Erd2p, for its recycling to the ER. DSL1 interacts genetically with mutations that affect components of the Golgi-to-ER recycling machinery, namely sec20-1, tip20-5, and COPI-encoding genes. Furthermore, we demonstrate that Dsl1p is a peripheral membrane protein, which in vitro specifically binds to coatomer, the major component of the protein coat of COPI vesicles.
Andag
U
U
Department of Molecular Genetics, Max-Planck-Institute for Biophysical Chemistry, D-37070 Göttingen, Germany.
Neumann
T
T
Schmitt
H D
HD
D000483:Alleles; D002462:Cell Membrane / Q000378:metabolism; D020756:Coatomer Protein / Q000378:metabolism*; D004721:Endoplasmic Reticulum / Q000378:metabolism* / Q000648:ultrastructure; D000939:Epitopes; D019084:Fluorescent Antibody Technique, Indirect; D005982:Glutathione Transferase / Q000378:metabolism; D006056:Golgi Apparatus / Q000378:metabolism* / Q000648:ultrastructure; D015151:Immunoblotting; D008565:Membrane Proteins / Q000378:metabolism; D009154:Mutation; D010641:Phenotype; D010957:Plasmids / Q000378:metabolism; D011485:Protein Binding; D021381:Protein Transport; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D050600:SNARE Proteins; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D013347:Subcellular Fractions; D013696:Temperature; D013997:Time Factors; D033921:Vesicular Transport Proteins
D020756:Coatomer Protein; C428365:DSL1 protein, S cerevisiae; D000939:Epitopes; D008565:Membrane Proteins; D011993:Recombinant Fusion Proteins; D050600:SNARE Proteins; D029701:Saccharomyces cerevisiae Proteins; D033921:Vesicular Transport Proteins; D005982:Glutathione Transferase