Question

What does actin’s troponin complex do when an action potential reaches it?

Answer 1

* Troponin is attached to the protein called tropomyosin which is present in the grooves of actin filaments in the muscle tissue. Troponin is present in both skeletal and cardiac muscles but the difference is number of calcium-ion binding sites. In skeletal mucle, there are four calcium binding sites and three for cardiac muscle.

* During contraction, the muscle cell get stimulated by action potential leads to the opening of calcium ion channels in sarcoplamic memembrane and calcium is released into sarcoplasm. This calcium binds to the troponin, which causes it to change shape(binding site) helps to bind myosin filaments(active sites) to actin filaments. This actin-myosin binding forms a cross bridge helps in the contraction of muscle.