title: Immunochemical and mutational analyses of P-type ATPase Spf1p involved in the yeast secretory pathway.
abstract: The yeast SPF1 gene encodes a novel P-type ATPase, the substrate of which specificity has not been identified. It is required for sensitivity to SMKT, a killer toxin produced by the halotolerant yeast Pichia farinosa. To investigate the function of Spf1p, Asp487, the putative phosphorylation site of Spf1p, was replaced by Asn. Expression of the altered SPF1, with Asp487 replaced by Asn, did not suppress the SMKT-resistant phenotype of spf1 mutants, suggesting that the catalytic activity of this ATPase is required for acquisition of sensitivity to SMKT. Subcellular fractionation experiments indicated that the fractionation pattern of Spf1p was similar to that of an early Golgi protein, Och1p. Cells lacking Spf1p had an abnormal fractionation pattern of Sec12p. The spf1 disruptant also showed increased expression of Kar2p and sensitivity to tunicamycin. The glycosylation-defective phenotype and possible role of Spf1p in the secretory pathway are discussed.
authors.affiliation: National Food Research Institute, Tsukuba, Ibaraki, Japan. csuzuki@nfri.affrc.go.jp
authors.forename: C
authors.initials: C
authors.lastname: Suzuki
mesh_terms: D018528:ATP-Binding Cassette Transporters; D000251:Adenosine Triphosphatases / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D025141:Drug Resistance, Fungal; D004721:Endoplasmic Reticulum / Q000378:metabolism; D005656:Fungal Proteins / Q000378:metabolism; D005800:Genes, Fungal; D006031:Glycosylation; D006056:Golgi Apparatus / Q000201:enzymology; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism; D007120:Immunochemistry; D055646:Killer Factors, Yeast; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D009183:Mycotoxins / Q000494:pharmacology; D010766:Phosphorylation; D010957:Plasmids / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins; D014415:Tunicamycin / Q000494:pharmacology
chemical_list: D018528:ATP-Binding Cassette Transporters; D005656:Fungal Proteins; D018840:HSP70 Heat-Shock Proteins; C060153:KAR2 protein, yeast; D055646:Killer Factors, Yeast; D009183:Mycotoxins; C406793:SPF1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D014415:Tunicamycin; D000251:Adenosine Triphosphatases