Phosphorylation of lipid metabolic enzymes by yeast protein kinase C requires phosphatidylserine and diacylglycerol.
Protein kinase C inSaccharomyces cerevisiae, i.e., Pkc1, is an enzyme that plays an important role in signal transduction and the regulation of lipid metabolic enzymes. Pkc1 is structurally similar to its counterparts in higher eukaryotes, but its requirement of phosphatidylserine (PS) and diacylglycerol (DAG) for catalytic activity has been unclear. In this work, we examined the role of these lipids in Pkc1 activity with protein and peptide substrates. In agreement with previous findings, yeast Pkc1 did not require PS and DAG for its activity on the peptide substrates derived from lipid metabolic proteins such as Pah1 [phosphatidate (PA) phosphatase], Nem1 (PA phosphatase phosphatase), and Spo7 (protein phosphatase regulatory subunit). However, the lipids were required for Pkc1 activity on the protein substrates Pah1, Nem1, and Spo7. Compared with DAG, PS had a greater effect on Pkc1 activity, and its dose-dependent interaction with the protein kinase was shown by the liposome binding assay. The Pkc1-mediated degradation of Pah1 was attenuated in thecho1Δ mutant, which is deficient in PS synthase, supporting the notion that the phospholipid regulates Pkc1 activity in vivo.
Department of Food Science and the Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, NJ 08901.
Prabuddha
P
Dey
Department of Food Science and the Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, NJ 08901.
Wen-Min
WM
Su
Department of Food Science and the Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, NJ 08901.
Gil-Soo
GS
Han
Department of Food Science and the Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, NJ 08901. Electronic address: gcarman@rutgers.edu.
George M
GM
Carman
D010717:CDPdiacylglycerol-Serine O-Phosphatidyltransferase / Q000235:genetics / Q000378:metabolism; D004075:Diglycerides / Q000378:metabolism*; D050356:Lipid Metabolism / Q000235:genetics*; D008565:Membrane Proteins / Q000378:metabolism; D009687:Nuclear Proteins / Q000378:metabolism; D010455:Peptides / Q000378:metabolism; D010711:Phosphatidate Phosphatase / Q000235:genetics / Q000378:metabolism*; D010718:Phosphatidylserines / Q000378:metabolism; D010766:Phosphorylation; D011493:Protein Kinase C / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000201:enzymology; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D013379:Substrate Specificity; D014280:Triglycerides / Q000378:metabolism
C490519:CHO1 protein, S cerevisiae; D004075:Diglycerides; D008565:Membrane Proteins; C502372:Nem1 protein, S cerevisiae; D009687:Nuclear Proteins; D010455:Peptides; D010718:Phosphatidylserines; C116365:SPO7 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D014280:Triglycerides; C490702:PKC1 protein, S cerevisiae; D011493:Protein Kinase C; D010717:CDPdiacylglycerol-Serine O-Phosphatidyltransferase; C079831:PAH1 protein, S cerevisiae; D010711:Phosphatidate Phosphatase
Cki1 choline kinase; Nem1-Spo7 protein phosphatase; Pah1 phosphatidate phosphatase; Ura7 CTP synthetase; yeast