除了dystrophin 还有哪些重要的肌纤维相关蛋白

Dystrophin is widely recognized for its critical role in maintaining muscle fiber integrity by linking the cytoskeleton to the extracellular matrix, with deficiencies leading to severe conditions like Duchenne muscular dystrophy. However, muscle function relies on a complex network of proteins beyond dystrophin, each contributing to structural support, contraction, and signaling. Understanding these proteins is essential for advancing research into neuromuscular diseases and developing targeted therapies.

Several key proteins include the sarcoglycan complex, composed of α, β, γ, and δ subunits, which stabilizes the sarcolemma as part of the dystrophin-associated glycoprotein complex; mutations here often cause limb-girdle muscular dystrophies. Utrophin, a dystrophin homolog expressed during muscle regeneration, can partially compensate for dystrophin loss and is a promising therapeutic target. Titin, the largest known protein, acts as a molecular spring, providing elasticity and passive tension to sarcomeres, while myosin and actin form the core contractile machinery—myosin thick filaments slide along actin thin filaments to generate force through the cross-bridge cycle. Regulatory proteins like troponin and tropomyosin fine-tune this process by controlling calcium-dependent interactions.

Additional vital proteins encompass desmin, an intermediate filament that maintains sarcomere alignment and organization; defects can result in desmin-related myopathies. Nebulin regulates actin filament length, ensuring precise sarcomere assembly, while calcium-handling proteins such as calsequestrin store calcium in the sarcoplasmic reticulum and the ryanodine receptor facilitates its release for excitation-contraction coupling. Integrins mediate cell-matrix adhesion, anchoring muscle fibers to the extracellular environment. Collectively, these proteins highlight the multifaceted nature of muscle biology, offering insights for diagnosing and treating disorders beyond those linked solely to dystrophin.