Alpha-actinin was initially isolated from rabbit skeletal muscle as a factor that induces the gelation of F-actin and promotes the superprecipitation of actomyosin. Alpha actinins are actin-binding proteins that carry out different purposes in different different cell types. In myofibrillar cells, alpha-actinin constitutes a major component of Z-discs in striated muscle and of the functionally analogous dense bodies and dense plaques in smooth muscle. Alpha-actinin(alpha A) shares structural homology with spectrin and dystrophin.
