first calponin homology (CH) domain found in the filamin family
The filamin family includes filamin-A (FLN-A), filamin-B (FLN-B) and filamin-C (FLN-C). Filamins function to anchor various transmembrane proteins to the actin cytoskeleton. FLN-A is also called actin-binding protein 280 (ABP-280), alpha-filamin, endothelial actin-binding protein, filamin-1, or non-muscle filamin. It promotes orthogonal branching of actin filaments and links actin filaments to membrane glycoproteins. It also serves as a scaffold for a wide range of cytoplasmic signaling proteins. FLN-B is also called ABP-278, ABP-280 homolog, actin-binding-like protein, beta-filamin, filamin homolog 1 (Fh1), filamin-3, thyroid autoantigen, truncated actin-binding protein, or truncated ABP. It connects cell membrane constituents to the actin cytoskeleton and may also promote orthogonal branching of actin filaments as well as link actin filaments to membrane glycoproteins. FLN-C, also called FLNc, ABP-280-like protein, ABP-L, actin-binding-like protein, filamin-2, or gamma-filamin, is a muscle-specific filamin that plays a central role in muscle cells, probably by functioning as a large actin-cross-linking protein. It may be involved in reorganizing the actin cytoskeleton in response to signaling events, and may also display structural functions at the Z lines in muscle cells. FLN-C is critical for normal myogenesis and for maintaining the structural integrity of the muscle fibers. This family also includes Drosophila melanogaster protein jitterbug (Jbug), which is an actin-meshwork organizing protein containing three copies of the CH domain. Other members of this family contain two copies of the CH domain. This model corresponds to the first CH domain. CH domains are actin filament (F-actin) binding motifs.