Isolation and localization of filamin in heart muscle.

High-molecular-mass protein was isolated from chicken heart muscle. The apparent molecular mass of a single polypeptide chain is similar to that of chicken gizzard filamin: 250–270 kDa. The protein interacts with antibodies against chicken gizzard filamin and induces F-actin gelation in a concentration-dependent manner. Immunofluorescent staining of cardiomyocytes and chicken heart sections with antifilamin antibody demonstrates two types of filamin localization: (a) filamin was located on the sarcomere border in the periphery of the Z-disk; (b) filamin was found in intercalated disks between cardiomyocytes. [ABSTRACT FROM AUTHOR]