Myosin Light Chain 6B, Alkali, Smooth Muscle And Non Muscle (MYL6B)

Myosin is composed of heavy chain (MHC) and light chain (MLC) subunits. Alkaline MLCs, such as MLC1SA, dissociate from MHCs at high pH. The deduced 208-amino acid protein has a calculated molecular mass of 22.7 kD. The N terminus is enriched in lysine, proline, and alanine residues, characteristic of alkaline MLCs. Northern blot analysis of rabbit muscle mRNA detected prominent expression in soleus, a slow-twitch skeletal muscle, with lower expression in fast-twitch muscle. In human, MLC1SA expression was detected in fibroblasts, primary myoblasts, and adult and fetal muscle. In mouse, Mlc1sa was expressed in soleus muscle, testis, and brain. Expression of MLC1SA appeared to be primarily associated with early and mature myotubes at the onset of muscle differentiation in both mice and humans.