Phosphorylation of Mg(2+)-dependent protein phosphatase alpha (type 2C alpha) by casein kinase II.
In this study we show that rat Mg(2+)-dependent protein phosphatase alpha (MPP alpha) expressed in Saccharomyces cerevisiae cells was phosphorylated on serine residues in vivo. The recombinant rat MPP alpha purified from Escherichia coli cells harboring an expression vector was phosphorylated in vitro by casein kinase II, but not by casein kinase I, to 1.5 mol phosphate per mol enzyme protein. Analysis by phosphopeptide mapping and amino acid analysis suggested that the sites of both in vivo and in vitro phosphorylation were the same and involved only serine residues. These results suggest that the rat MPP alpha expressed in yeast cells is phosphorylated by yeast casein kinase II in vivo. It is further proposed that the phosphorylation sites are located in the carboxyl terminal region of the enzyme molecule.
Department of Biochemistry, Tohoku University, Sendai, Japan.
T
T
Kobayashi
S
S
Kanno
T
T
Terasawa
T
T
Murakami
M
M
Ohnishi
K
K
Ohtsuki
A
A
Hiraga
S
S
Tamura
D000595:Amino Acid Sequence; D000818:Animals; D001921:Brain / Q000201:enzymology; D047390:Casein Kinase II; D002417:Cattle; D003001:Cloning, Molecular; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000235:genetics; D007527:Isoenzymes / Q000378:metabolism*; D008274:Magnesium / Q000494:pharmacology*; D008969:Molecular Sequence Data; D010449:Peptide Mapping; D010748:Phosphopeptides / Q000302:isolation & purification; D010749:Phosphoprotein Phosphatases / Q000378:metabolism*; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D051381:Rats; D011994:Recombinant Proteins / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D013950:Thymus Gland / Q000201:enzymology
D007527:Isoenzymes; D010748:Phosphopeptides; D011994:Recombinant Proteins; D047390:Casein Kinase II; D017346:Protein Serine-Threonine Kinases; D010749:Phosphoprotein Phosphatases; D008274:Magnesium