There are several isoforms of this protein but the one found predominantly in muscle is the 427kDa isoform. Dystrophin is made up of four domains: an N-terminal, a rod domain composed of 24 triple helix repeats and 4 hinges, a cysteine-rich domain and a C-terminal. The N-terminal of the protein binds to actin filaments and acts as a bridge between the actin cytoskeleton and the extracellular matrix via interactions with the dystroglycan complex (DGC) in the sarcolemma in muscles (5). Dystrophin helps to increase membrane stability and prevent the sarcolemma from rupturing. Absence of dystrophin leads to the disassembly of the DGC leaving the sarcolemma vulnerable to damage when muscles contract (6). Skeletal and cardiac muscle cells that lack, or have an insufficient amount of, functional dystrophin progressively become more damaged as the muscles keep contracting and relaxing. Damaged muscle cells weaken and eventually die, which is what causes the muscle weakness and cardiomyopathy seen in DMD
There are several isoforms of this protein but the one found predominantly in muscle is the 427kDa isoform. Dystrophin is made up of four domains: an N-terminal, a rod domain composed of 24 triple helix repeats and 4 hinges, a cysteine-rich domain and a C-terminal. The N-terminal of the protein binds to actin filaments and acts as a bridge between the actin cytoskeleton and the extracellular matrix via interactions with the dystroglycan complex (DGC) in the sarcolemma in muscles (5). Dystrophin helps to increase membrane stability and prevent the sarcolemma from rupturing. Absence of dystrophin leads to the disassembly of the DGC leaving the sarcolemma vulnerable to damage when muscles contract (6). Skeletal and cardiac muscle cells that lack, or have an insufficient amount of, functional dystrophin progressively become more damaged as the muscles keep contracting and relaxing. Damaged muscle cells weaken and eventually die, which is what causes the muscle weakness and cardiomyopathy seen in DMD