Molecular motors of myosin

Myosins are microfilament-binding proteins that were first discovered in muscle tissue, with many non-myocyte myosins gradually being discovered after 1970. There are 13 members of the family, each of which is structurally divided into three parts, head, neck and tail, resembling bean sprouts, and composed of both light and heavy chains. The regulatory light chain is the site of myosin mediation, i.e., the phosphorylation/dephosphorylation status of the regulatory light chain affects myosin activity. Of these, types I and II are the most thoroughly studied molecular motors. Some cells have mutant myosins that extend pseudopods normally, but do not move them successfully. Types I and V, on the other hand, are dimers. Tend to move toward the positive pole of the microfilament. The head of the protein flexes and extends in relation to the tail, and pulls the microfilaments backward in relation to each other during "flexion". In addition to being involved in muscle contraction, myosin is thought to be one of the important molecules required for cell migration

. It is very likely that myosin is involved in the contraction of the cytosol in the "four steps forward". In addition, myosin is also observed at the protruding end of the cell, where it may be helping to transport proteins that are needed for adhesion, improving the efficiency of adhesion.