Actin-binding protein, or filamin, is a 280-kD protein that crosslinks actin filaments into orthogonal networks in cortical cytoplasm and participates in the anchoring of membrane proteins for the actin cytoskeleton. Remodeling of the cytoskeleton is central to the modulation of cell shape and migration. Filamin A, encoded by the FLNA gene, is a widely expressed filamin that regulates the reorganization of the actin cytoskeleton by interacting with integrins, transmembrane receptor complexes, and secondary messengers. At least 31 disease-causing mutations in this gene have been discovered.