Actin

Definition

Actin is a globular protein that forms long, thin filaments which are a major component of the cytoskeleton in all eukaryotic cells and is crucial in the contraction of skeletal muscles. It works together with myosin to convert chemical energy into mechanical energy, leading to muscle movement.

Related terms

Myosin: A motor protein that interacts with actin filaments to cause muscle contraction by pulling on the actin fibers, similar to how an engine pulls a train along its tracks.

Sarcomere: The basic functional unit of striated muscle fibers, composed of repeating units of actin and myosin, organized into a precise arrangement that contracts and relaxes muscles.

Tropomyosin: A regulatory protein that wraps around actin filaments, blocking myosin binding sites until calcium ions cause it to shift and allow for muscle contraction