title: Function of the ypt2 gene in the exocytic pathway of Schizosaccharomyces pombe.
abstract: The ypt2 gene of the fission yeast Schizosaccharomyces pombe encodes a member of the ypt/rab family of small GTP-binding proteins, related in sequence to Sec4p of Saccharomyces cerevisiae but closer to mammalian rab8. We have introduced a mutation into the gene corresponding to a mutation identified in ypt1, in which a conserved valine residue was altered to asparagine. The mutated ypt2 gene was introduced into the S. pombe genome by gene replacement. The resulting strain was temperature-sensitive for growth. Normal growth was restored by introduction of a plasmid-borne wild-type ypt2 cDNA or by cDNA for rab8 but not by various other rab or ypt sequences. At restrictive temperature the mutant cells accumulated the secretory protein acid phosphatase in a form that appeared to be fully glycosylated and acquired a population of vesicles detectable by electron microscopy. Thus the ypt2 protein, and by inference rab8, appear to function in the last stage of the secretory pathway.
authors.affiliation: Imperial Cancer Research Fund, London, England.
authors.forename: M W
authors.initials: MW
authors.lastname: Craighead
authors.forename: S
authors.initials: S
authors.lastname: Bowden
authors.forename: R
authors.initials: R
authors.lastname: Watson
authors.forename: J
authors.initials: J
authors.lastname: Armstrong
mesh_terms: D000135:Acid Phosphatase / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D004285:Dogs; D005089:Exocytosis / Q000235:genetics*; D020558:GTP Phosphohydrolases; D019204:GTP-Binding Proteins / Q000737:chemistry / Q000235:genetics* / Q000502:physiology; D005800:Genes, Fungal / Q000235:genetics*; D005816:Genetic Complementation Test; D008854:Microscopy, Electron; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D017354:Point Mutation / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000235:genetics; D012568:Schizosaccharomyces / Q000235:genetics* / Q000502:physiology / Q000648:ultrastructure; D029702:Schizosaccharomyces pombe Proteins; D013104:Spheroplasts / Q000378:metabolism; D013696:Temperature; D014170:Transformation, Genetic; D020691:rab GTP-Binding Proteins
chemical_list: D029702:Schizosaccharomyces pombe Proteins; D000135:Acid Phosphatase; C064393:ypt2 protein, S pombe; D020558:GTP Phosphohydrolases; D019204:GTP-Binding Proteins; D020691:rab GTP-Binding Proteins