Sarcospan

Sarcospan is a protein encoded by the SSPN gene in humans. It is a component of the dystrophin-associated glycoprotein complex (DGC), a large multi-protein complex located at the muscle cell membrane (sarcolemma) and involved in maintaining muscle fiber integrity and signaling.

Function:

Sarcospan plays a role in stabilizing the DGC and mediating cell adhesion. It interacts with other DGC components, including dystroglycans and sarcoglycans. Through these interactions, sarcospan contributes to the structural stability of the muscle cell membrane, protecting it from damage during muscle contraction and relaxation. It may also be involved in cell signaling pathways related to muscle development and repair.

Structure:

Sarcospan is a transmembrane protein, meaning it spans the cell membrane. It has a single transmembrane domain and extracellular and intracellular domains. The extracellular domain is involved in interactions with other DGC components.

Clinical Significance:

Mutations in the SSPN gene have been linked to certain forms of muscular dystrophy, specifically limb-girdle muscular dystrophy (LGMD). Dysfunctional or absent sarcospan can disrupt the stability of the DGC, leading to muscle weakness and degeneration characteristic of muscular dystrophy. Research suggests that sarcospan may also play a role in other muscle-related disorders and possibly cancer, although further investigation is needed. It is currently being investigated as a potential therapeutic target for muscular dystrophies due to its ability to influence DGC stability.

See also:

• Dystrophin-associated glycoprotein complex (DGC)
• Dystrophin
• Dystroglycan
• Sarcoglycan
• Limb-girdle muscular dystrophy (LGMD)
• Muscular dystrophy