Actin

Definition

Actin is a globular protein that polymerizes to form long, thin filaments essential for various cellular functions, including movement and structural integrity. It is a key component of the cytoskeleton in eukaryotic cells.

5 Must Know Facts For Your Next Test

1. Actin filaments are dynamic structures that can rapidly assemble and disassemble, allowing cells to change shape and move.
2. In muscle cells, actin interacts with myosin to facilitate contraction through a process known as the sliding filament theory.
3. Actin plays a crucial role in cytokinesis by forming the contractile ring that separates dividing cells.
4. The polymerization of actin is regulated by various proteins such as profilin and cofilin.
5. Actin filaments provide structural support to cell membranes through their interaction with proteins like spectrin.

Review Questions

• What role does actin play in muscle cell contraction?
• How do actin filaments contribute to cell division?
• Name two proteins that regulate the polymerization of actin.

Related terms

Myosin: A motor protein that interacts with actin filaments to produce movement.

Cytoskeleton:

A network of protein fibers in the cytoplasm of eukaryotic cells that provides structural support and facilitates cellular motion.

Profilin: A protein that binds to actin monomers and regulates their polymerization into filaments.