Fig. 1.

Organization of the dystrophin-glycoprotein complex.

The dystrophin-glycoprotein complex is a core element of the extracellular matrix-sarcolemma-cytoskeleton axis and provides stability to the surface membrane structure of skeletal muscle fibres during excitation-contraction-relaxation cycles. The main sarcolemmal complex consists of the extracellular proteins α-dystroglycan (α-DG) and laminin, the plasmalemmal proteins β-dystroglycan (β-DG), α-sarcoglycan (α-SG), β-sarcoglycan (β-SG), γ-sarcoglycan (γ-SG), δ-sarcoglycan (δ-SG) and sarcospan (SSPN), and the cytosolic proteins dystrophin (Dp427), syntrophins (SYN), dystrobrevins (DYB), cortical actin and the enzyme neuronal nitric oxide synthase nNOS. Collagen molecules are linked to the dystrophin-glycoprotein complex through interactions with laminin in the extracellular matrix, and the actin membrane cytoskeleton forms together with microtubules and intermediate filaments the intracellular matrix of muscle fibres.