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Phosphorylation of Yeast Nem1‐Spo7 Protein Phosphatase Complex by Protein Kinase C
Author(s) -
Dey Prabuddha,
Su WenMin,
Han GilSoo,
Carman George M.
Publication year - 2018
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2018.32.1_supplement.539.2
Subject(s) - phosphatidate , biochemistry , diacylglycerol kinase , dephosphorylation , protein kinase a , phosphatase , protein subunit , phosphorylation , biology , protein phosphatase 2 , phosphoprotein , c raf , protein kinase c , mitogen activated protein kinase kinase , chemistry , microbiology and biotechnology , gene
Pah1 phosphatidate phosphatase in the yeast Saccharomyces cerevisiae catalyzes the dephosphorylation of phosphatidate to produce diacylglycerol. This is the penultimate step in the synthesis of triacylglycerol in yeast and higher eukaryotes. Pah1 is primarily found in the cytosol as a physiologically inactive phosphoprotein, but becomes active through its translocation to the nuclear/ER membrane, where its substrate phosphatidate resides. The membrane translocation of Pah1 occurs via its dephosphorylation by the membrane‐associated protein phosphatase complex Nem1 (catalytic subunit)‐Spo7 (regulatory subunit). In this work, we showed that both Nem1 and Spo7 were phosphorylated by protein kinase C on serine residues. The phosphorylations of each subunit were dependent on their concentrations, phosphatidylserine, diacylglycerol, the amount of protein kinase C, ATP, and the time of the reactions. Peptides derived from Nem1 and Spo7 that contained putative protein kinase C target sites were tested as substrates for the kinase. The Nem1 peptide containing Ser‐201 and the Spo7 peptide containing Ser‐22 and Ser‐28 were substrates for protein kinase C. That Ser‐201 and Ser‐22 and Ser‐28, respectively, were targets in the Nem1 and Spo7 peptides were confirmed by a combination of mass spectrometry and mutagenesis to alanine residues. Full‐length Nem1 S201A and Spo7 S22A and S28A mutant proteins isolated from yeast were defective in their phosphorylations by protein kinase C. Support or Funding Information Supported by NIH grant GM050679. This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .