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 475000 determined by ultracentrifugation and gel filtration, is a complex of two polypeptides with apparent molecular weights of 250000 and 240000. 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/∼ 12–14 mol actin monomer allowing microfilament association, as shown by electron microscopy.