A novel protein phosphatase-1 inhibitory protein potentiated by protein kinase C. Isolation from porcine aorta media and characterization.
A novel phosphorylation-dependent inhibitory protein (IP) of porcine aorta myosin light chain phosphatase (PA-MLCP) was purified to homogeneity from porcine aorta media. The molecular mass of IP was 20 kDa. IP phosphorylated by endogenous potentiating kinase (IP-K) inhibited not only PA-MLCP activity, but also that of the catalytic subunit of protein phosphatase-1. The amino acid sequence of a peptide derived from IP phosphorylated with IP-K, RHARVT*VK, shared one of the consensus sequences phosphorylatable by protein kinase C (PKC), where T* was phosphorylated. IP was phosphorylated by PKC and the phosphorylated product inhibited PA-MLCP as strongly as IP phosphorylated with IP-K.
Eto
M
M
Division of Chemistry, Hokkaido University.
Ohmori
T
T
Suzuki
M
M
Furuya
K
K
Morita
F
F
D000595:Amino Acid Sequence; D000818:Animals; D001011:Aorta / Q000378:metabolism*; D002352:Carrier Proteins; D002845:Chromatography; D002852:Chromatography, Ion Exchange; D017886:Durapatite; D004791:Enzyme Inhibitors / Q000302:isolation & purification / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins; D007700:Kinetics; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000302:isolation & purification; D010749:Phosphoprotein Phosphatases / Q000037:antagonists & inhibitors*; D011493:Protein Kinase C / Q000378:metabolism*; D054645:Protein Phosphatase 1; D011506:Proteins / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism*; D013552:Swine; D017540:Tunica Media / Q000378:metabolism*
D002352:Carrier Proteins; D004791:Enzyme Inhibitors; D047908:Intracellular Signaling Peptides and Proteins; D010446:Peptide Fragments; D011506:Proteins; C021042:protein phosphatase inhibitor-1; D017886:Durapatite; D011493:Protein Kinase C; D010749:Phosphoprotein Phosphatases; D054645:Protein Phosphatase 1