Myosin regulatory light chain phosphorylation by ROCK

Stable Identifier
Reaction [transition]
Homo sapiens
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Nonmuscle myosin II (NMM2) is an actin-based motor protein that plays a crucial role in a variety of cellular processes, including smooth muscle contraction, cell migration, polarity formation, and cytokinesis. NMM2 consists of two myosin heavy chains encoded by MYH9, MYH10, MYH14 (NMHC-IIA, B and C) or MYH11, two copies of MYL6 essential light chain protein, and two regulatory light chains (MRLCs), MYL9 and MYL12B. Myosin II activity is stimulated by phosphorylation of MRLC. Diphosphorylation at Thr-19 and Ser-20 (commonly referred in the literature as Thr-18 and Ser-19) increases both actin-activated Mg2+ ATPase activity and the stability of myosin II filaments; monophosphorylation at Ser-20 is less effective (Ikebe and Hartshorne 1985, Ikebe et al. 1988). Kinases responsible for the phosphorylation include myosin light chain kinase (MLCK), ROCK kinase, citron kinase, myotonic dystrophy kinase-related CDC42-binding protein kinase, and Zipper-interacting protein (ZIP) kinase. ROCK activity has been shown to regulate MRLC phosphorylation by directly mono- or diphosphorylating MRLC (Amano et al., 1996, Ueda et al., 2002, Watanabe et al. 2007).

Literature References
PubMed ID Title Journal Year
3839510 Phosphorylation of smooth muscle myosin at two distinct sites by myosin light chain kinase

Ikebe, M, Hartshorne, DJ

J. Biol. Chem. 1985
8702756 Phosphorylation and activation of myosin by Rho-associated kinase (Rho-kinase)

Amano, M, Ito, M, Kimura, K, Fukata, Y, Chihara, K, Nakano, T, Matsuura, Y, Kaibuchi, K

J Biol Chem 1996
2966156 Effects of phosphorylation of light chain residues threonine 18 and serine 19 on the properties and conformation of smooth muscle myosin

Ikebe, M, Koretz, J, Hartshorne, DJ

J. Biol. Chem. 1988
17151359 Regulation of myosin II dynamics by phosphorylation and dephosphorylation of its light chain in epithelial cells

Watanabe, T, Hosoya, H, Yonemura, S

Mol Biol Cell 2007
12185584 Rho-kinase contributes to diphosphorylation of myosin II regulatory light chain in nonmuscle cells

Ueda, K, Murata-Hori, M, Tatsuka, M, Hosoya, H

Oncogene 2002
Participant Of
Catalyst Activity
Catalyst Activity
protein serine/threonine kinase activity of Activated ROCK:RhoA/B/C:GTP [plasma membrane]
Physical Entity
Inferred From
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