MYO5A antibody

Myosin Va (p190) is a member of the unconventional class of myosins, distinct from both the myosins I and myosins II. It is present in neuronal and non neuronal cells of the brain. Class V myosins are widely expressed actin-based motors that have been implicated in the transport and/or localization of a wide range of organelles as well as mRNA. Class V myosins have two motor head domains typical of myosins, and an extended regulatory neck domain with six tandem IQ domains that bind multiple calmodulin light chains. In addition, myosin V contains a unique 400 amino acids globular tail domain that may direct myosin V to its target or determine the cargo to which it binds. Brain myosin Va exhibits an unusually high affinity for F-actin. In the presence of ATP, its Mg-ATPase activity is stimulated by physiological Ca2+ concentrations in a highly cooperative manner. Based on biochemical properties, kinetic and optical measurements, it has been suggested that myosin Va is a processive, actinbased molecular motor. Myosin Va has been implicated in the regulation of vesicle trafficking in neurons and melanocytes. It has been suggested that class V myosins associate with membrane vesicles through their C-terminal tails. Myosin V associates with synaptic vesicles and forms a stable complex with the synaptic vesicle membrane proteins, synaptobrevin II, and synaptophysin. The dilute Myo5a gene mutation in myosin Va leads to mental retardation, variable cellular immunodeficiency and impaired melanocyte function (pigmentary dilution), known as Griscelli syndrome in humans. Myosin Va regulates melanosome distribution along microfilaments. It is found in association with the centrosome at all stages of the cell cycle. In the interphase stage, myosin Va is found in pericentriolar material. During cell division, it is found in the cytoplasm and concentrates in a trail between migrating centrioles and in the mitotic spindle poles and spindle fibers.