What role does the dystrophin protein play in muscle cells?

Dystrophin is a critical protein that plays a vital role in maintaining the structural integrity of muscle cells. Its primary functions include:1

• Protection: It protects the cell membrane of skeletal, heart, and diaphragm muscles during the process of contraction.1
• Structural Linkage: It acts as a bridge by binding actin filaments located inside the cell to components of the dystrophin-associated glycoprotein complex (DGC) on the exterior of the cell membrane.1

When dystrophin is absent or defective—as seen in Duchenne muscular dystrophy and Becker muscular dystrophy—the muscle cell membrane becomes weakened. This instability leads to the entry of excess calcium ions into the cell, causing progressive muscle degradation and eventual cell death.21