Myosin Light Chain Kinases

Myosin Light Chain Kinases (MLCKs) are a group of protein serine/threonine kinases that is currently divided into two subtypes, MLCK1 and MLCK2. MLCK1 is found in smooth muscle and phosphorylates myosin II regulatory light chains at Ser¹⁹, allowing myosin crossbridges to bind to actin filaments and initiate contraction.

In addition to smooth muscle contraction, MLCK1 is involved in a diverse range of biological processes including control of endothelial and vascular permeability, growth initiation of astrocytes processes, neurotransmitter release in the sympathetic nervous system and apoptosis of fibroblasts. MLCK2 is found in striated muscle and co-localizes with phosphorylated MLC filaments to mediate skeletal and cardiac muscle contraction. MLCK3 and MLCK4 have recently been identified but are yet to be fully characterized. MLCKs are activated by Ca²⁺-calmodulin complexes and require Mg²⁺ or Ca²⁺ as a co-factor.

External sources of pharmacological information for Myosin Light Chain Kinases :

• IUPHAR Receptor Code

• BJP Guide

Myosin Light Chain Kinase Gene Data