Isolation and structural properties of a high-molecular-weight actin-binding protein (filamin-like protein) in hog thyroid gland.

A high-molecular-weight protein has been isolated from hog thyroid gland. This protein, with a molecular weight of 475,000 determined by ultracentrifugation and gel filtration, is a complex of two polypeptides with apparent molecular weights of 250,000 and 240,000. It may be related to filamin-like proteins by its physicochemical properties and its immunogenic cross-reactivity towards gizzard filamin antibodies. Furthermore it interacts with F-actin in a stoichiometry of 1 mol of high-molecular-weight protein/approximately 12-14 mol actin monomer allowing microfilament association, as shown by electron microscopy.