SIGMA A5441-.5ML

The two major cytoskeletal proteins implicated in cell motility are actin and myosin. Actin and myosin are constituents of many cell types and are involved in cellular process including locomotion, secretion, cytoplasmic streaming, phagocytosis, and cytokinesis. Although actin is one of the most conserved eukaryotic proteins, it is expressed in mammals and birds as at least six isoforms characterized by electrophoresis and amino acid sequence analysis. Four of them represent the differentiation markers of muscle tissues and two are found practically in all cells. There are three alpha-actins (skeletal, cardiac, and smooth muscle), one beta-actin (beta-nonmuscle), and two gamma-actins (gamma-smooth muscle and gamma-nonmuscle). Actin isoforms show>90% overall sequence homology, but only 50-60% homology in their NH2-terminal residues.