Abstract
New method for purification of phosphatase inhibitor 1 (PPI-1) was developed which avoid the phosphorylation of PPI-1 during the purification and provides a high yield of highly pure preparation. Using this preparation, it was shown that PPI-1 was stoichiometrically phosphorylated by cGMP-dependent protein kinase at Thr-35 and the phosphorylated PPI-1 potently inhibited protein phosphatase 1. Addition of the phosphorylated PPI-1 to beta-escin-skinned single smooth muscle cells resulted in force development of the cells at the submaximal pCa2+. The results suggest that the phosphorylation of PPI-1 can be the mechanism for modifying the Ca2+ sensitivity of smooth muscle contractile response.
Publication types
-
Research Support, Non-U.S. Gov't
-
Research Support, U.S. Gov't, P.H.S.
MeSH terms
-
Amino Acid Sequence
-
Animals
-
Carrier Proteins*
-
Chromatography, Ion Exchange
-
Cyclic AMP-Dependent Protein Kinases / antagonists & inhibitors
-
Cyclic GMP-Dependent Protein Kinases / metabolism*
-
Enzyme Inhibitors / metabolism
-
Enzyme Inhibitors / pharmacology*
-
Gizzard, Avian
-
Intracellular Signaling Peptides and Proteins*
-
Kinetics
-
Molecular Sequence Data
-
Muscle Contraction / drug effects*
-
Muscle, Skeletal / chemistry
-
Muscle, Skeletal / physiology
-
Muscle, Smooth, Vascular / drug effects
-
Muscle, Smooth, Vascular / enzymology
-
Muscle, Smooth, Vascular / physiology*
-
Myosin-Light-Chain Kinase / metabolism
-
Peptide Fragments / chemistry
-
Peptide Fragments / isolation & purification
-
Peptides / pharmacology
-
Phosphopeptides / chemistry
-
Phosphopeptides / isolation & purification
-
Phosphorylation
-
Portal Vein
-
Proteins / isolation & purification
-
Proteins / metabolism
-
Proteins / pharmacology*
-
Rabbits
-
Turkeys
Substances
-
Carrier Proteins
-
Enzyme Inhibitors
-
Intracellular Signaling Peptides and Proteins
-
Peptide Fragments
-
Peptides
-
Phosphopeptides
-
Proteins
-
protein phosphatase inhibitor-1
-
Cyclic AMP-Dependent Protein Kinases
-
Cyclic GMP-Dependent Protein Kinases
-
Myosin-Light-Chain Kinase