Yeast mutants affecting possible quality control of plasma membrane proteins.
Mutations gef1, stp22, STP26, and STP27 in Saccharomyces cerevisiae were identified as suppressors of the temperature-sensitive alpha-factor receptor (mutation ste2-3) and arginine permease (mutation can1(ts)). These suppressors inhibited the elimination of misfolded receptors (synthesized at 34 degrees C) as well as damaged surface receptors (shifted from 22 to 34 degrees C). The stp22 mutation (allelic to vps23 [M. Babst and S. Emr, personal communication] and the STP26 mutation also caused missorting of carboxypeptidase Y, and ste2-3 was suppressed by mutations vps1, vps8, vps10, and vps28 but not by mutation vps3. In the stp22 mutant, both the mutant and the wild-type receptors (tagged with green fluorescent protein [GFP]) accumulated within an endosome-like compartment and were excluded from the vacuole. GFP-tagged Stp22p also accumulated in this compartment. Upon reaching the vacuole, cytoplasmic domains of both mutant and wild-type receptors appeared within the vacuolar lumen. Stp22p and Gef1p are similar to tumor susceptibility protein TSG101 and voltage-gated chloride channel, respectively. These results identify potential elements of plasma membrane quality control and indicate that cytoplasmic domains of membrane proteins are translocated into the vacuolar lumen.
Li
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Department of Molecular Genetics and Microbiology, University of Massachusetts Medical School, Worcester, Massachusetts 01655-0122, USA.
Kane
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Tipper
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Spatrick
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Jenness
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D000595:Amino Acid Sequence; D026905:Amino Acid Transport Systems; D026923:Amino Acid Transport Systems, Basic; D002462:Cell Membrane / Q000378:metabolism*; D003001:Cloning, Molecular; D011992:Endosomes / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins; D000072235:Mating Factor; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000235:genetics; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D009154:Mutation; D010455:Peptides / Q000235:genetics; D017510:Protein Folding; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins; D017386:Sequence Homology, Amino Acid; D013489:Suppression, Genetic
D026905:Amino Acid Transport Systems; D026923:Amino Acid Transport Systems, Basic; C502212:CAN1 protein, S cerevisiae; D005656:Fungal Proteins; D008164:Luminescent Proteins; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D010455:Peptides; D011956:Receptors, Cell Surface; D029701:Saccharomyces cerevisiae Proteins; D049452:Green Fluorescent Proteins; C043909:arginine permease; D000072235:Mating Factor