Regulation of phospholipid biosynthetic enzymes by the level of CDP-diacylglycerol synthase activity.
Amine-containing phospholipid synthesis in Saccharomyces cerevisiae starts with the conversion of CDP-diacylglycerol (CDP-DAG) and serine to phosphatidylserine (PS), whereas phosphatidylinositol (PI) is formed from CDP-DAG and inositol (derived from inositol 1-phosphate). In this study the regulation of PS synthase (encoded by CHO1/PSS), PI synthase (encoded by PIS1), and inositol 1-phosphate synthase (encoded by INO1) activities by the in vivo level of CDP-DAG synthase activity (encoded by CDS1) is described. Reduction in the level of CDP-DAG synthase activity from 10-fold over wild type levels to 10% of wild type levels results in a 7-fold increase in PS synthase activity, which follows a similar change in the CHO1/PSS mRNA level. INO1 mRNA also increases but only after CDP-DAG synthase activity falls below the wild type level. PI synthase activity follows the decrease of the CDP-DAG synthase activity, but there is no parallel change in the level of PIS1 mRNA. These changes in CHO1/PSS and INO1 mRNA levels are mediated by a mechanism not dependent on changes in the expression of the INO2-OPI1 regulatory genes. CDS1 expression is repressed in concert with INO2 expression in response to inositol.
Shen
H
H
Department of Biochemistry and Molecular Biology, University of Texas-Houston Medical School, Houston, Texas 77225, USA.
Dowhan
W
W
D051607:CDP-Diacylglycerol-Inositol 3-Phosphatidyltransferase; D002798:Diacylglycerol Cholinephosphotransferase / Q000235:genetics / Q000378:metabolism*; D004790:Enzyme Induction; D015971:Gene Expression Regulation, Enzymologic; D007296:Myo-Inositol-1-Phosphate Synthase / Q000096:biosynthesis; D019884:Nitrogenous Group Transferases; D010743:Phospholipids / Q000096:biosynthesis*; D012333:RNA, Messenger / Q000032:analysis; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D014166:Transferases / Q000096:biosynthesis; D017855:Transferases (Other Substituted Phosphate Groups) / Q000096:biosynthesis
D010743:Phospholipids; D012333:RNA, Messenger; D014166:Transferases; D019884:Nitrogenous Group Transferases; D017855:Transferases (Other Substituted Phosphate Groups); C022370:phospholipid serine base exchange enzyme; D051607:CDP-Diacylglycerol-Inositol 3-Phosphatidyltransferase; D002798:Diacylglycerol Cholinephosphotransferase; D007296:Myo-Inositol-1-Phosphate Synthase