Receptor-induced vascular smooth muscle cell contraction is mediated by dual regulation of myosin light chain (MLC(20)) phosphorylation through Ca(2+)-dependent stimulation of myosin light chain kinase and Rho/Rho-kinase-mediated inhibition of myosin phosphatase. Although myosin light chain kinase regulation is initiated by the coupling of receptors to G proteins of the G(q) family, G(q) and G(...

Repetitive strain stimulates intestinal epithelial migration across fibronectin via focal adhesion kinase (FAK), Src, and extracellular signal-related kinase (ERK) although how these signals act and interact remains unclear. We hypothesized that PI3K is central to this pathway. We subjected Caco-2 and intestinal epithelial cell-6 cells to 10 cycles/min deformation on flexible fibronectin-coated...

The protein present in various vertebrate tissues as smooth muscle, adrenal medulla, brain and platelets, previously identified with troponin C, has been found [ 1,2] to be identical with modulator protein of cyclic nucleotide phosphodiesterase. This protein was also found in skeletal and cardiac muscles, i.e., in the tissues which contain troponin C. Most of modulator protein was present in th...

Platelet contractile forces play a major role in clot retraction and help to hold hemostatic clots against the vessel wall. Platelet forces are produced by its cytoskeleton, which is composed of actin and nonmuscle myosin filaments. In this work, we studied the role of Rho kinase, myosin light-chain kinase, and myosin in the generation of contractile forces by using pharmacological inhibitors a...

Contractile actomyosin networks generate forces that drive tissue morphogenesis. Actomyosin contractility is controlled primarily by reversible phosphorylation of the myosin-II regulatory light chain through the action of myosin kinases and phosphatases. While the role of myosin light-chain kinase in regulating contractility during morphogenesis has been largely characterized, there is surprisi...

Calmodulin-dependent myosin light chain kinase phosphorylates two light chain subunits on each myosin molecule. We have developed a method for measuring nonphosphorylated, monophosphorylated, and diphosphorylated forms of myosin in smooth muscle. Four protein bands were separated in tissue extracts by nondenaturing polyacrylamide gel electrophoresis in the presence of pyrophosphate. Immunoblots...

Nonmuscle myosin II (myosin hereafter) has well-established roles in generating contractile force on actin filaments during morphogenetic processes in all metazoans. Myosin activation is regulated by phosphorylation of the myosin regulatory light chain (MRLC, encoded by spaghettisquash or sqh in Drosophila) first on Ser21 and subsequently on Thr20. These phosphorylation events are positively co...