first calponin homology (CH) domain found in the dystrophin family
The dystrophin family includes dystrophin and its paralog, utrophin. Dystrophin, encoded by the DMD gene, is a large, submembrane cytoskeletal protein that is the main component of the dystrophin-glycoprotein complex (DGC) in skeletal muscles. It links the transmembrane DGC to the actin cytoskeleton through binding strongly to the cytoplasmic tail of beta-dystroglycan, the transmembrane subunit of a highly O-glycosylated cell-surface protein. Dystrophin is also involved in maintaining the structural integrity of cells, as well as in the formation of the blood-brain barrier (BBB). Utrophin, also called dystrophin-related protein 1 (DRP-1), is an autosomal dystrophin homolog that increases dystrophic muscle function and reduces pathology. It is broadly expressed in both the mRNA and protein levels, and occurs in the cerebrovascular endothelium. Utrophin forms the utrophin-glycoprotein complex (UGC) by interacting with dystroglycans (DGs) and sarcoglycan-dystroglycans, as well as sarcoglycan and sarcospan (SG-SSPN) subcomplexes. It may act as a scaffolding protein that stabilizes lipid microdomains and clusters mechanosensitive channel subunits, and links the F-actin cytoskeleton to the cell membrane via the associated glycoprotein complex. 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.