Master Of Medicine

Troponin

Troponin is a complex of three regulatory proteins.

Troponin T-Attaches troponin complex to Tropomyosin

Troponin I-Binds troponin complex to actin

Troponin C–Calcium binding troponin

Tropomyosin

Covers the sites where myosin heads bind actin.

Troponin-Tropomyosin complex inhibits the interaction between actin and myosin in a resting muscle.

How does muscle contract?

Image via Wikipedia

Calcium is released from SR in response to action potential and it binds to troponin C and causes conformational change in Troponin-Tropomyosin -Actin unit, myosin binding sites become uncovered leading to muscle contraction.