Contractile Proteins of Cultured Cells

Abstract

Abstract An actin-like protein was isolated from the acetone powder of glycerinated chick embryo fibroblasts and purified to electrophoretic homogeneity as shown by sodium dodecyl sulfate polyacrylamide gel electrophoresis. The purified protein has a molecular weight of 45,500, resembles rabbit actin in electrophoretic mobility and ultrastructure, undergoes reversible globular-fibrous transformations, and combines with rabbit myosin to form hybrid actomyosin. This actomyosin exhibits ATPase activity and superprecipitation properties similar to those of actomyosin from rabbit muscle. In fibroblasts, the actin-like protein may function in the maintenance of shape and in the implementation of intra- and extracellular movements.