Tropomyosin

Definition

Tropomyosin is a protein involved in muscle contraction. It blocks the binding sites on actin filaments, preventing myosin from attaching and initiating contraction until calcium ions are present.

5 Must Know Facts For Your Next Test

1. Tropomyosin is a regulatory protein that binds along the length of actin filaments.
2. In the presence of calcium ions, tropomyosin undergoes a conformational change, allowing myosin to bind to actin.
3. Tropomyosin works closely with another regulatory protein called troponin.
4. It plays a critical role in skeletal and cardiac muscle function by controlling the interaction between actin and myosin.
5. Mutations or malfunctions in tropomyosin can lead to muscle diseases such as cardiomyopathies.

Review Questions

• What is the primary function of tropomyosin in muscle contraction?
• How does tropomyosin interact with calcium ions during muscle contraction?
• Name one potential consequence of mutations in the tropomyosin protein.

Related terms

Actin: A globular multi-functional protein that forms microfilaments and is essential for cellular functions including muscle contraction.

Myosin: A type of motor protein that interacts with actin to produce muscle contraction.

Troponin: A complex of three regulatory proteins integral to muscle contraction, which binds to calcium and moves tropomyosin away from actin's binding sites.