Troponin I plays a crucial role in the contractile process of muscle cells. It is responsible for preventing the interaction between actin and myosin when the muscle is in a relaxed state. During muscle contraction, calcium ions bind to troponin C, causing a conformational change that moves the troponin-tropomyosin complex away from the actin binding sites. This allows myosin heads to bind to actin, facilitating contraction.
