Filamins are a family of dimeric actin binding proteins that function as structural components of cell adhesion sites. They also serve as a scaffold for subcellular targeting of signaling molecules . The actin binding domain (alpha-actinin domain) located at the amino terminus is followed by as many as 24 tandem repeats of about 96 residues and the dimerization domain is located at the carboxy terminus. In addition to actin filaments, filamins associate with other structural and signaling molecules such as beta-integrins, Rho/Rac/Cdc42, PKC and the insulin receptor, primarily through the carboxy-terminal dimerization domain. Filamin A, the most abundant, and filamin B are widely expressed isoforms, while filamin C is predominantly expressed in muscle. Filamin A is phosphorylated by PAK1 at Ser2152, which is required for PAK1-mediated actin cytoskeleton reorganization.
