Troponin C

Troponin C

Structure of Troponin C

Troponin C is a component of the troponin complex, which is essential for the regulation of muscle contraction in skeletal and cardiac muscle. Troponin C binds calcium ions, which is a critical step in the process of muscle contraction.

Structure

Troponin C is a small, globular protein that is part of the troponin complex, which also includes troponin I and troponin T. The structure of Troponin C allows it to bind calcium ions, which induces a conformational change necessary for muscle contraction.

Function

The primary function of Troponin C is to bind calcium ions during muscle contraction. When calcium binds to Troponin C, it causes a shift in the position of the troponin complex on the actin filament. This shift exposes the myosin binding sites on actin, allowing the myosin heads to attach and initiate contraction.

Role in Muscle Contraction

Troponin complex on actin filament

In the absence of calcium, the troponin complex inhibits the interaction between actin and myosin. When calcium levels increase, calcium ions bind to Troponin C, leading to a conformational change that moves the troponin complex away from the myosin binding sites on actin. This allows the myosin heads to bind to actin, resulting in muscle contraction.

Clinical Significance

Troponin C, along with other components of the troponin complex, is often measured in the blood to assess heart muscle damage. However, it is primarily troponin I and troponin T that are used as biomarkers in the diagnosis of myocardial infarction.

Related Pages

• Troponin I
• Troponin T
• Muscle contraction
• Calcium ion
• Myocardial infarction