Troponin C, fast skeletal muscle (sTnC) is a protein that in humans is encoded by the TNNC2 gene. It is the troponin C paralog expressed in fast-twitching fibers of skeletal muscle.

Troponin (Tn), is a key protein complex in the regulation of striated muscle contraction, composed of three subunits. The TnI subunit inhibits actomyosin ATPase, the TnT subunit binds tropomyosin and TnC, while the TnC subunit binds calcium and overcomes the inhibitory action of the troponin complex on actin thin filaments. The protein encoded by the TNNC2 gene is the TnC subunit.

There are already multiple troponin activators that bind to fast skeletal troponin C (TNNC2), of which tirasemtiv has been tested in multiple clinical trials.

Further reading