Molecular cloning of a novel phosphorylation-dependent inhibitory protein of protein phosphatase-1 (CPI17) in smooth muscle: its specific localization in smooth muscle.
The cDNA encoding a phosphorylation-dependent inhibitory protein of protein phosphatase-1 (PP1) was isolated from a porcine aorta library. The coding region represented the complete amino acid sequence of this protein comprised of a novel 147-residue polypeptide, which we termed CPI17, a 17-kDa PKC-potentiated inhibitory protein of PP1. As well as the native CPI17 from porcine aorta, the recombinant protein completely suppressed the PP1 activity (IC50 = 0.18 nM) by the stoichiometric thiophosphorylation. The CPI17 mRNA is expressed in smooth muscle tissues such as aorta and bladder, whereas little expression was observed in heart, skeletal muscle, and non-muscle tissues. These results suggest a specific regulatory mechanism of the PP1 activity through CPI17 in smooth muscle.
Eto
M
M
Division of Chemistry, Graduate School of Science, Hokkaido University, Sapporo, Japan.
Senba
S
S
Morita
F
F
Yazawa
M
M
D000595:Amino Acid Sequence; D000818:Animals; D001011:Aorta / Q000737:chemistry; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary; D004791:Enzyme Inhibitors / Q000032:analysis*; D008969:Molecular Sequence Data; D009124:Muscle Proteins / Q000032:analysis* / Q000235:genetics; D009131:Muscle, Smooth, Vascular / Q000737:chemistry*; D010749:Phosphoprotein Phosphatases / Q000037:antagonists & inhibitors*; D010750:Phosphoproteins; D010766:Phosphorylation; D054645:Protein Phosphatase 1; D012333:RNA, Messenger; D017386:Sequence Homology, Amino Acid; D013552:Swine
D018076:DNA, Complementary; D004791:Enzyme Inhibitors; D009124:Muscle Proteins; D010750:Phosphoproteins; D012333:RNA, Messenger; D010749:Phosphoprotein Phosphatases; D054645:Protein Phosphatase 1