In the absence of calcium ions, TnI binds to actin and inhibits the interaction between actin and myosin, thereby preventing muscle contraction. When calcium ions are released from the sarcoplasmic reticulum during muscle activation, they bind to TnC. This binding induces a conformational change in the troponin complex, causing TnI to release from actin. As a result, the inhibition is lifted, allowing myosin to interact with actin and initiate muscle contraction.
