Telethonin (TCAP)

Telethonin is a small protein localized to the Z-disc of striated muscle, encoded by the TCAP gene on chromosome 17. It regulates the assembly and stability of sarcomeres—the contractile units of muscle—and interacts with titin and other sarcomeric proteins to maintain muscle fiber structure. Telethonin is essential for proper muscle development, function, and adaptation, and its activity can be modulated by phosphorylation via several kinases. Dysfunction due to TCAP mutations causes LGMD2G, marked by early onset skeletal muscle weakness, scapular winging, and calf hypertrophy. Telethonin has also been implicated in various cardiomyopathies and can modulate cell death pathways, indicating wider functions in muscle physiology and disease.

Other names

TCAPTitin-cap protein

For investigational therapies, gene replacement delivers functional copies of TCAP to restore normal telethonin protein production