Myomesin

Myomesin is an end line protein that is part of the M line. It is a protein found in the M-band of muscle sarcomeres in association with M-protein. It is found in both slow and fast muscle fibers while M-protein is only found in fast fibers. These proteins are thought to be involved in anchoring the thick filaments of the sarcomere (myosin) to other filaments, namely titin, stabilizing and aligning the structure. It may function as a molecular spring that protects the sarcomere and keeps it stable during intense or sustained stretching. While its specific function is still not completely understood, it has been shown that it is closely associated with myosin as it is present in all skeletal and cardiac muscle from the earliest stages of muscle tissue formation.