N-myristoylation is required for function of the pheromone-responsive G alpha protein of yeast: conditional activation of the pheromone response by a temperature-sensitive N-myristoyl transferase.
In a screen designed to identify novel mutations in the mating response pathway of Saccharomyces cerevisiae, we isolated conditional alleles of NMT1, the gene encoding N-myristoyl transferase. Genetic data indicate that Nmt1 deficiency results in the activation of the pheromone response at the level of Gpa1, the alpha subunit of the pheromone-responsive G protein. We show that Gpa1 is myristoylated by Nmt1, and without this normally stable modification, Gpa1 is unable to inhibit pheromone signaling. This loss of Gpa1 function is probably not the result of improper subcellular localization. Unlike the mammalian G alpha i proteins alpha i and alpha o, nonmyristoylated Gpa1 is able to associate with membranes. In addition to Gpa1, our data indicate that Nmt1 myristoylates other proteins essential to vegetative growth.
Research Institute of Scripps Clinic, Molecular Biology Department, La Jolla, California 92037.
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D000217:Acyltransferases / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D015153:Blotting, Western; D019204:GTP-Binding Proteins / Q000378:metabolism* / Q000502:physiology; D005800:Genes, Fungal / Q000502:physiology; D007700:Kinetics; D000072235:Mating Factor; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D019814:Myristic Acid; D009227:Myristic Acids / Q000378:metabolism*; D010455:Peptides / Q000494:pharmacology; D010675:Pheromones / Q000494:pharmacology; D016133:Polymerase Chain Reaction; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000254:growth & development / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology*; D013696:Temperature; D001616:beta-Galactosidase / Q000235:genetics / Q000378:metabolism
D009227:Myristic Acids; D010455:Peptides; D010675:Pheromones; D011993:Recombinant Fusion Proteins; D019814:Myristic Acid; D000072235:Mating Factor; D000217:Acyltransferases; C050480:glycylpeptide N-tetradecanoyltransferase; D001616:beta-Galactosidase; D019204:GTP-Binding Proteins