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

Prabuddha Dey,Wen-Min Su,Gil-Soo Han,George M Carman

doi:10.1194/jlr.m075036

Prabuddha Dey, Wen-Min Su + Show 2 more

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https://doi.org/10.1194/jlr.m075036

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Abstract

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.

Highlights

IntroductionProtein kinase C in Saccharomyces cerevisiae, i.e., Pkc, is an enzyme that plays an important role in signal transduction and the regulation of lipid metabolic enzymes
Protein kinase C in Saccharomyces cerevisiae, i.e., yeast protein kinase C (Pkc1), is an enzyme that plays an important role in signal transduction and the regulation of lipid metabolic enzymes
Using the protein and peptide substrates, we found that Pkc1 has a different requirement of PS and DAG for catalytic activity: the lipids were required for Pkc1 activity on Pah1, but not for its peptide

Summary

Introduction

Protein kinase C in Saccharomyces cerevisiae, i.e., Pkc, is an enzyme that plays an important role in signal transduction and the regulation of lipid metabolic enzymes. Pkc is structurally similar to its counterparts in higher eukaryotes, but its requirement of phosphatidylserine (PS) and diacylglycerol (DAG) for catalytic activity has been unclear. We examined the role of these lipids in Pkc activity with protein and peptide substrates. In agreement with previous findings, yeast Pkc did not require PS and DAG for its activity on the peptide substrates derived from lipid metabolic proteins such as Pah1 [phosphatidate (PA) phosphatase], Nem (PA phosphatase phosphatase), and Spo (protein phosphatase regulatory subunit). The lipids were required for Pkc activity on the protein substrates Pah, Nem, and Spo. Phosphorylation of lipid metabolic enzymes by yeast protein kinase C requires phosphatidylserine and diacylglycerol.

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