Utrophin, also termed dystrophin-related protein 1 (DRP-1), is an autosomal dystrophin homologue that increases dystrophic muscle function and reduces pathology. It is broadly expressed at both the mRNA and protein levels, and occurs in the cerebrovascular endothelium. Utrophin forms the utrophin-glycoprotein complex (UGC) by interacting with the dystroglycans (DGs) and the sarcoglycan-dystroglycans, sarcoglycans and sarcospan (SG-SSPN) subcomplex. It may act as a scaffolding protein that stabilizes lipid microdomains and clusters mechanosensitive channel subunits, and link the F-actin cytoskeleton to the cell membrane via the associated glycoprotein complex. Like dystrophin, Utrophin has a compact cluster of domains comprising four EF-hand-like motifs and a ZZ-domain, followed by a looser region with two coiled-coils. These domains are believed to be involved in protein-protein interactions. In addition, it contains two syntrophin binding sites (SBSs) and a long N-terminal extension that comprises two actin-binding calponin homology (CH) domains, up to 24 spectrin repeats (SRs) and a WW domain. However, utrophin lacks the intrinsic microtubule binding activity of dystrophin SRs.