Filamin A was initially discovered in 1975 as a 280 kDa actin-binding protein in rabbit alveolar macrophages (Hartwig and Stossel 1975), and was named Actin-Binding Protein 280 (ABP280). In the same year, Wang and colleagues described a high-molecular-weight nonmuscle actin-binding protein in chicken gizzard extracts and called it filamin because it was localized on actin filaments (Wang et al. 1975). The suspicion that ABP280 and filamin were the same protein was confirmed 15 years later with the cloning of the ABP280/filamin gene (Gorlin et al. 1993). Today we know that mammals have three filamins; in addition to filamin A (gene symbol FLNA, chromosome Xq28), two other genes with high homology to filamin A were cloned in 1998 and 2000, respectively called filamin β and FLN2 (Takafuta et al. 1998, Thompson et al. 2000). FLNA is the most broadly...