Myosin

Myosin light chain kinase (MLCK) is a ubiquitous Ca2+/calmodulin (CaM)-activated kinase found in smooth, cardiac, and skeletal muscle as well as in mammalian nonmuscle cells. Myosin light chain kinase (MLCK) is a regulatory protein forsmooth muscle contraction, which acts by phosphorylating 20-kDamyosin light chain (MLC20) to activate the myosin ATPase activity.Myosin light chain kinase (MLCK) of smooth muscle hasbeen puried as an enzyme that phosphorylates 20-kDa lightchain of smoothmuscle myosin (MLC20). Analysis of the cross talk between Ras-ERK and PI3K-AKT signaling pathways reveals integrin β1, myosin light chain kinase (MLCK) and myosin IIA are required for the activation of PI3K-AKT following inhibition of the Ras-ERK pathway. Integrin β1, MLCK, and myosin IIA are factors in the development of resistance to MEK inhibitors. Myosin light chain kinase (MLCK) phosphorylates the regulatory light chain (RLC) of myosin producing increases in force development during skeletal muscle contraction.