A novel 20 kDa phosphorylation-dependent inhibitory protein isolated from porcine aorta media inhibited PA-MLCP activity when phosphorylated by protein kinase C.
Identification of a novel 20 kDa protein from porcine aorta that, upon phosphorylation by PKC, inhibits myosin light chain phosphatase, providing insights into vascular smooth muscle regulation.
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 et al. (Fri,) reported a other. Protein Phosphatase-1 Inhibitory Protein (IP) was evaluated on Inhibition of PA-MLCP activity and catalytic subunit of protein phosphatase-1. A novel 20 kDa phosphorylation-dependent inhibitory protein isolated from porcine aorta media inhibited PA-MLCP activity when phosphorylated by protein kinase C.