Myosin

Myosins are a large family of motor proteins that share the common features of ATP hydrolysis (ATPase enzyme activity), actin binding and potential for kinetic energy transduction. Originally isolated from muscle cells (hence the name), almost all eukaryotic cells are now known to contain myosins.

Structurally, mysoins contain a 'head' domain that binds to actin filaments (microfilaments) and is the site of ATP hydrolysis. The 'tail' domain interacts with cargo molecules, and the 'neck' acts as a linker between the head and tail and is the site of regulatory myosin light chain binding.

There are 17 myosin families and the most well characterized is myosin II. Myosin II is found predominantly in myocytes and mediates plus-ended movement along microfilaments. It is involved in muscle contraction through cyclic interactions with actin-rich thin filaments, creating a contractile force. It is regulated by phosphorylation via Myosin Light Chain Kinase (MLCK) and by intracellular Ca²⁺ concentrations.

External sources of pharmacological information for Myosin :

• BJP Guide

Myosin Gene Data