Saccharomyces cerevisiae contains four fatty acid activation (FAA) genes: an assessment of their role in regulating protein N-myristoylation and cellular lipid metabolism

• Published in: The Journal of cell biology Vol. 127; no. 3; pp. 751 - 762
• Main Authors: Johnson, D.R. (Washington University School of Medicine, St. Louis, MO.), Knoll, L.J, Levin, D.E, Gordon, J.I
• Format: Journal Article
• Language: English
• Published: United States Rockefeller University Press 01.11.1994; The Rockefeller University Press
• Subjects: ACILTRANSFERASA; Acyl Coenzyme A - metabolism; ACYLTRANSFERASE; Alleles; Amino Acid Sequence; Animals; Bacteria - genetics; Base Sequence; Cell growth; Cells; Cellular biology; COMPOSICION QUIMICA; COMPOSITION CHIMIQUE; ESTER; ESTERES; Fatty Acid Synthases - metabolism; Fatty acids; Fatty Acids - metabolism; Fungal Proteins - genetics; Fungal Proteins - metabolism; GENE; Gene expression regulation; GENES; Genes, Fungal; Humans; Lipid Metabolism; Mammals; Metabolism; METABOLISME DES LIPIDES; METABOLISMO DE LIPIDOS; Molecular Sequence Data; Myristates; Myristic Acid; Myristic Acids - metabolism; Oligodeoxyribonucleotides; Palmitates; Phylogeny; Plasmids; Protein Processing, Post-Translational; Proteins; REACCIONES QUIMICAS; REACTION CHIMIQUE; SACCHAROMYCES CEREVISIAE; Saccharomyces cerevisiae - genetics; Saccharomyces cerevisiae - growth & development; Saccharomyces cerevisiae - metabolism; Saccharomyces cerevisiae Proteins; SECUENCIA NUCLEICA; Sequence Homology, Amino Acid; SEQUENCE NUCLEIQUE; Yeast; Yeasts
• ISSN: 0021-9525; 1540-8140
• DOI: 10.1083/jcb.127.3.751

Saccharomyces cerevisiae has been used as a model for studying the regulation of protein N-myristoylation. MyristoylCoA:protein N-myristoyl-transferase (Nmt1p), is essential for vegetative growth and uses myristoylCoA as its substrate. MyristoylCoA is produced by the fatty acid synthetase (Fas) complex and by cellular acylCoA synthetases. We have recently isolated three unlinked Fatty Acid Activation (FAA) genes encoding long chain acylCoA synthetases and have now recovered a fourth by genetic complementation. When Fas is active and NMT1 cells are grown on media containing a fermentable carbon source, none of the FAA genes is required for vegetative growth. When Fas is inactived by a specific inhibitor (cerulenin), NMT1 cells are not viable unless the media is supplemented with long chain fatty acids. Supplementation of cellular myristoylCoA pools through activation of imported myristate (C14:0) is predominantly a function of Faa1p, although Faa4p contributes to this process. Cells with nmt181p need larger pools of myristoylCoA because of the mutant enzymes reduced affinity for this substrate. Faa1p and Faa4p are required for maintaining the viability of nmr1-181 strains even when Fas is active. Overexpression of Faa2p can rescue nmt1-181 cells due to activation of an endogenous pool of C14:0. This pool appears to be derived in part from membrane phospholipids since overexpression of Plb1p, a nonessential lysophospholipase/ phospholipase B, suppresses the temperature-sensitive growth arrest and C14:0 auxotrophy produced by nmt1-181. None of the four known FAAs is exclusively responsible for targeting imported fatty acids to peroxisomal beta-oxidation pathways. Introduction of a peroxisomal assembly mutation, pas1 delta, into isogenic NMT1 and nmt1-181 strains with wild type FAA alleles revealed that when Fas is inhibited, peroxisomes contribute to myristoylCoA pools used by Nmt1p. When Fas is active, a fraction of cellular myristoylCoA is targeted to peroxisomes. A