A Novel Protein Phosphatase-1 Inhibitory Protein Potentiated by Protein Kinase C. Isolation from Porcine Aorta Media and Characterization

Masumi Eto; Toshihiro Ohmori; Masashi Suzuki; Kenji Furuya; Fumi Morita

Masumi Eto, Toshihiro Ohmori, Masashi Suzuki, Kenji Furuya, Fumi Morita

Author information

Keywords: aorta smooth muscle, myosin light chain phosphatase, phosphorylation, protein kinase C, protein phosphatase-1 inhibitor

JOURNAL FREE ACCESS

1995 Volume 118 Issue 6 Pages 1104-1107

Details

Abstract

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.

Corresponding author

Register with J-STAGE for free!