Myosin is a highly conserved, ubiquitous protein found in all eukaryotic cells, where it provides the motor function for diverse movements such as cytokinesis, phagocytosis, and muscle contraction. All myosins contain an amino-terminal motor/head domain and a carboxy-terminal tail domain. The class II myosins, consist of the conventional two-headed myosins that form filaments and are composed of two myosin heavy chain (MYH) subunits and four myosin light chain subunits. There are 15 MYH genes identified as Class II myosins and these include six skeletal muscle MYHs (MYH1, MYH2, MYH3, MYH4, MYH8, MYH13), three cardiac MYHs (MYH6, MYH7, MYH7B) and two non-muscle MYHs (MYH9, MYH10), as well as a smooth muscle MYH (MYH11).
