title: Genes encoding farnesyl cysteine carboxyl methyltransferase in Schizosaccharomyces pombe and Xenopus laevis.
abstract: The mam4 mutation of Schizosaccharomyces pombe causes mating deficiency in h- cells but not in h+ cells. h- cells defective in mam4 do not secrete active mating pheromone M-factor. We cloned mam4 by complementation. The mam4 gene encodes a protein of 236 amino acids, with several potential membrane-spanning domains, which is 44% identical with farnesyl cysteine carboxyl methyltransferase encoded by STE14 and required for the modification of a-factor in Saccharomyces cerevisiae. Analysis of membrane fractions revealed that mam4 is responsible for the methyltransferase activity in S. pombe. Cells defective in mam4 produced farnesylated but unmethylated cysteine and small peptides but no intact M-factor. These observations strongly suggest that the mam4 gene product is farnesyl cysteine carboxyl methyltransferase that modifies M-factor. Furthermore, transcomplementation of S. pombe mam4 allowed us to isolate an apparent homolog of mam4 from Xenopus laevis (Xmam4). In addition to its sequence similarity to S. pombe mam4, the product of Xmam4 was shown to have a farnesyl cysteine carboxyl methyltransferase activity in S. pombe cells. The isolation of a vertebrate gene encoding farnesyl cysteine carboxyl methyltransferase opens the way to in-depth studies of the role of methylation in a large body of proteins, including Ras superfamily proteins.
authors.affiliation: Department of Biophysics and Biochemistry, Graduate School of Science, University of Tokyo, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Imai
authors.forename: J
authors.initials: J
authors.lastname: Davey
authors.forename: M
authors.initials: M
authors.lastname: Kawagishi-Kobayashi
authors.forename: M
authors.initials: M
authors.lastname: Yamamoto
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002462:Cell Membrane / Q000201:enzymology; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins; D015870:Gene Expression; D005796:Genes / Q000235:genetics; D005800:Genes, Fungal / Q000235:genetics*; D005816:Genetic Complementation Test; D036341:Intercellular Signaling Peptides and Proteins; D008969:Molecular Sequence Data; D009865:Oocytes; D010455:Peptides; D010675:Pheromones; D011496:Protein Methyltransferases / Q000235:genetics*; D012333:RNA, Messenger / Q000032:analysis; D015183:Restriction Mapping; D012568:Schizosaccharomyces / Q000201:enzymology / Q000235:genetics*; D029702:Schizosaccharomyces pombe Proteins; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D014982:Xenopus laevis
chemical_list: D004268:DNA-Binding Proteins; D036341:Intercellular Signaling Peptides and Proteins; C089516:Mating Factor, S pombe; D010455:Peptides; D010675:Pheromones; D012333:RNA, Messenger; D029702:Schizosaccharomyces pombe Proteins; C490320:mfm1 protein, S pombe; D011496:Protein Methyltransferases; C056501:protein-S-isoprenylcysteine O-methyltransferase