Cross-talk between Rho-associated Kinase and Cyclic Nucleotide-dependent Kinase Signaling Pathways in the Regulation of Smooth Muscle Myosin Light Chain Phosphatase

Abstract

Background: Myosin phosphatase is regulated by multisite phosphorylation of its myosin targeting subunit of MLCP (MYPT1) subunit. Results: Multisite phosphorylation at Ser 696 , Thr 697 , Ser 854 , and Thr 855 has no effect on activity; phosphorylation at Thr 697 and Thr 855 is inhibitory. Conclusion: Cross-talk between cyclic nucleotide and RhoA signaling pathways occurs at both MYPT1 inhibitory sites. Significance: Knowledge of MYPT1 phosphorylation is key to understanding the molecular basis of smooth muscle contractile regulation.