title: Phosphorylation of the modulator protein of the ATP, Mg-dependent protein phosphatase by casein kinase TS. Reversal by PCS phosphatases and control by distinct phosphorylation site(s).
abstract: The phosphorylation by casein kinase TS (II) of the modulator protein of the ATP, Mg-dependent phosphatase increases after preincubation with the PCSH1 phosphatase or with the catalytic subunit of the ATP, Mg-dependent phosphatase. Dephosphorylation by the two phosphatases combined leads to the incorporation of 2 mol phosphate per mol modulator (at Ser residues). Occupancy of the ATP, Mg-dependent phosphatase phosphorylation site(s) is a negative determinant in the phosphorylation of the modulator by kinase TS. Among the PCS phosphatases PCSH1 shows the highest activity toward the 32P-Ser residues labeled by kinase TS in untreated or previously dephosphorylated modulator, while the ATP, Mg-dependent phosphatase is totally ineffective. Protamine stimulates all phosphatase activities, so that the catalytic subunit of the ATP, Mg-dependent phosphatase becomes almost as effective as the PCSC phosphatase in dephosphorylating the kinase TS sites.
mesh_terms: D000255:Adenosine Triphosphate / Q000494:pharmacology; D047388:Casein Kinases; D008274:Magnesium / Q000494:pharmacology; D010749:Phosphoprotein Phosphatases / Q000378:metabolism / Q000494:pharmacology*; D010766:Phosphorylation; D011073:Polyamines; D000071228:Polyelectrolytes; D011108:Polymers / Q000494:pharmacology*; D011494:Protein Kinases / Q000494:pharmacology*; D011506:Proteins / Q000378:metabolism*; D000097847:Protein Phosphatase Inhibitory Proteins
chemical_list: D000255:Adenosine Triphosphate; D047388:Casein Kinases; D008274:Magnesium; D010749:Phosphoprotein Phosphatases; D011073:Polyamines; D000071228:Polyelectrolytes; D011108:Polymers; D011494:Protein Kinases; D011506:Proteins; C024833:protein phosphatase inhibitor-2; D000097847:Protein Phosphatase Inhibitory Proteins