Phosphorylation of lipid metabolic enzymes by yeast protein kinase C requires phosphatidylserine and diacylglycerol

• Published in: Journal of lipid research 2017-04, Vol.58 (4), p.742-751
• Main Authors: Dey, Prabuddha, Su, Wen-Min, Han, Gil-Soo, Carman, George M.
• Format: Article
• Language: English
• Subjects: Biodegradation; CDPdiacylglycerol-Serine O-Phosphatidyltransferase - genetics; CDPdiacylglycerol-Serine O-Phosphatidyltransferase - metabolism; Cki1 choline kinase; Diglycerides; Diglycerides - metabolism; Enzymes; Kinases; Lipid Metabolism - genetics; Lipids; Membrane Proteins - metabolism; Metabolism; Nem1-Spo7 protein phosphatase; Nuclear Proteins - metabolism; Pah1 phosphatidate phosphatase; Peptides - metabolism; Phosphatase; Phosphatidate Phosphatase - genetics; Phosphatidate Phosphatase - metabolism; Phosphatidylserine; Phosphatidylserines - metabolism; Phospholipids; Phosphorylation; Protein kinase C; Protein Kinase C - genetics; Protein Kinase C - metabolism; Protein phosphatase; Proteins; Saccharomyces cerevisiae; Saccharomyces cerevisiae - enzymology; Saccharomyces cerevisiae Proteins - genetics; Saccharomyces cerevisiae Proteins - metabolism; Signal transduction; Substrate Specificity; Triglycerides - metabolism; Ura7 CTP synthetase; yeast
• ISSN: 0022-2275; 1539-7262
• DOI: 10.1194/jlr.M075036

Protein kinase C in Saccharomyces 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 the cho1Δ mutant, which is deficient in PS synthase, supporting the notion that the phospholipid regulates Pkc1 activity in vivo.