Myosin Light Chain 9, Regulatory (MYL9)

MYL9 is a myosin light chain that may regulate muscle contraction by modulating the ATPase activity of myosin heads. The encoded protein binds calcium and is activated by myosin light chain kinase. Two transcript variants encoding different isoforms have been found for this gene. MYL9 had an apparent molecular mass of 20 kD following in vitro translation. Northern blot analysis detected a 1-kb transcript in umbilical artery, colon, and uterus, but not in cardiac or skeletal muscle. Expression was also detected in foreskin fibroblasts and human fibroblast cell lines, but not in hemopoietic cell lines. Two-dimensional gel analysis confirmed that MYL9 was present in fibroblasts, but not in T cells.