Meta-Biol

• Pathways

In non-muscle cells, phosphorylation of myosin II regulates actomyosin contractility. The level of myosin phosphorylation depends mainly on the balance of two enzymes, the Ca2+-dependent MLC kinase (MLCK), and myosin phosphatase (MLCP). Phosphorylation of the regulatory light chain of myosin II (MRLC) induces its interaction with actin, activating myosin ATPase and resulting in enhanced cell contractility. Myosin phosphatase decreases MRLC phosphorylation, which inhibits binding to filamentous actin and stress fibre formation (Kimura et al. 1996, Nakai et al. 1997, Katoh et al. 2001, Iwasaki et al. 2001).