Actin

Definition

Actin is a globular multi-functional protein that forms microfilaments. It plays a critical role in muscle contraction by interacting with myosin to produce force and movement.

5 Must Know Facts For Your Next Test

1. Actin filaments, also known as thin filaments, are essential components of the cytoskeleton.
2. In muscle cells, actin filaments are organized into sarcomeres, which are the functional units of muscle contraction.
3. During muscle contraction, actin filaments slide past myosin filaments due to the interaction between actin and myosin heads.
4. Actin is involved not only in muscle contraction but also in cell motility, division, and intracellular transport.
5. ATP binding and hydrolysis regulate the polymerization and depolymerization of actin filaments.

Review Questions

• What role does actin play in muscle contraction?
• How do actin filaments interact with myosin during muscle contraction?
• What other cellular processes involve actin besides muscle contraction?

Related terms

Myosin: A motor protein that interacts with actin to generate force for muscle contractions.

Sarcomere: The basic contractile unit of striated muscle tissue composed of repeating sections of actin and myosin.

Cytoskeleton:

A network of fibers composed of proteins like actin that provide structural support for cells.