The Saccharomyces cerevisiae PLB1 gene encodes a protein required for lysophospholipase and phospholipase B activity

• Published in: The Journal of biological chemistry 1994-08, Vol.269 (31), p.19725-19730
• Main Authors: Lee, K.S. (Johns Hopkins University, School of Public Health, Baltimore, MD.), Patton, J.L, Fido, M, Hines, L.K, Kohlwein, S.D, Paltauf, F, Henry, S.A, Levin, D.E
• Format: Article
• Language: English
• Subjects: ACILTRANSFERASA; ACTIVIDAD ENZIMATICA; ACTIVITE ENZYMATIQUE; ACYLTRANSFERASE; ACYLTRANSFERASES; Amino Acid Sequence; AMINO ACID SEQUENCES; Analytical, structural and metabolic biochemistry; Base Sequence; Biological and medical sciences; CELL MEMBRANES; CHEMICAL COMPOSITION; CHROMOSOME; Chromosome Mapping; CHROMOSOMES; COMPOSICION QUIMICA; COMPOSITION CHIMIQUE; CROMOSOMAS; DELETIONS; DNA, Fungal; Enzyme Activation; Enzymes and enzyme inhibitors; ENZYMIC ACTIVITY; ESTERASAS; ESTERASE; ESTERASES; FOSFOLIPIDOS; Fundamental and applied biological sciences. Psychology; Fungal Proteins - genetics; Fungal Proteins - metabolism; GENBANK/L23089; GENE; GENES; Genes, Fungal; GENETICA; GENETICS; GENETIQUE; Hydrolases; Lysophospholipase - metabolism; MEMBRANAS CELULARES; MEMBRANE CELLULAIRE; Membrane Proteins; METABOLITE; METABOLITES; METABOLITOS; MOLECULAR MAPPING; MOLECULAR SEQUENCE DATA; MUTANT; MUTANTES; MUTANTS; NUCLEOTIDE SEQUENCE; OPEN READING FRAMES; PHOSPHATIDE; PHOSPHOLIPIDS; Phospholipids - metabolism; PLASMA MEMBRANES; REGULATORY SEQUENCES; SACCHAROMYCES CEREVISIAE; Saccharomyces cerevisiae - enzymology; Saccharomyces cerevisiae - genetics; Saccharomyces cerevisiae Proteins; SECUENCIA NUCLEOTIDICA; Sequence Homology, Amino Acid; SEQUENCE NUCLEOTIDIQUE; STRUCTURAL GENES
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/S0021-9258(17)32081-1

Several enzymes with lysophospholipase/phospholipase B activity have been described from the budding yeast Saccharomyces cerevisiae. In vitro, these enzymes are capable of hydrolyzing all phospholipids that can be extracted from yeast cells. Two forms of the enzyme have been isolated from plasma membranes and a third from culture supernatants and the periplasmic space, but their biological roles have not been determined. These highly glycosylated enzymes were reported to have very similar catalytic properties but differed with respect to apparent molecular weight. We isolated a gene from S. cerevisiae, encoding a protein predicted to share 45% amino acid sequence identity with phospholipase B from Penicillium notatum. This yeast gene, designated PLB1, was mapped to the left arm of chromosome VIII. No residual lysophospholipase/phospholipase B activity was detected upon assay of extracts or culture supernatants of a plb1 delta mutant. Thus, either the PLB1 gene encodes all of the previously detected isoforms of phospholipase B or its gene product is required for their expression or activation. Deletion of PLB1 did not result in any apparent phenotypic defect, suggesting either that we failed to identify the growth conditions that would betray such a defect or that Plb1p is functionally redundant with another protein, whose activity has gone undetected. A plb1 delta mutant released wild-type levels of the soluble phosphatidylinositol metabolite glycerophosphoinositol into the growth medium but released greatly reduced levels of the corresponding phosphatidylcholine and phosphatidylethanolamine metabolites. These results indicate that PLB1 is principally responsible for the production of the deacylation products of phosphatidylcholine and phosphatidylethanolamine but not phosphatidylinositol.