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Title: Phosphorylation of yeast plasma membrane H+-ATPase by casein kinase I
Authors: Estrada, E ×
Agostinis, Patrizia
Vandenheede, Jackie
Goris, Jozef
Merlevede, Wilfried
François, J
Ghislain, M #
Issue Date: Dec-1996
Series Title: Journal of Biological Chemistry vol:271 issue:50 pages:32064-72
Abstract: The plasma membrane H+-ATPase of Saccharomyces cerevisiae is subject to phosphorylation by a casein kinase I activity in vitro. We show this casein kinase I activity to result from the combined function of YCK1 and YCK2, two highly similar and plasma membrane-associated casein kinase I homologues. First, H+-ATPase phosphorylation is severely impaired in the plasma membrane of YCK-deficient yeast strains. Furthermore, the wild-type level of the phosphoprotein is restored by the addition of purified mammalian casein kinase I to the mutant membranes. We used the H+-ATPase as well as a synthetic peptide substrate that contains a phosphorylation site for casein kinase I to compare kinase activity in membranes prepared from yeast cells grown in the presence or absence of glucose. The addition of glucose results in increased H+-ATPase activity which is associated with a decline in the phosphorylation level of the enzyme. Mutations in both YCK1 and YCK2 affect this regulation, suggesting that H+-ATPase activity is modulated by glucose via a combination of a "down-regulating" casein kinase I activity and another, yet uncharacterized, "up-regulating" kinase activity. Biochemical mapping of phosphorylated H+-ATPase identifies a major phosphopeptide that contains a consensus phosphorylation site (Ser-507) for casein kinase I. Site-directed mutagenesis of this consensus sequence indicates that Glu-504 is important for glucose-induced decrease in the apparent Km for ATP.
ISSN: 0021-9258
Publication status: published
KU Leuven publication type: IT
Appears in Collections:Biochemistry Section (Medicine) (-)
Laboratory of Protein Phosphorylation and Proteomics
Laboratory of Cell Death Research & Therapy
× corresponding author
# (joint) last author

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