actin ac·tin (āk'tĭn)
One of the protein components found in muscle, existing as F-actin or G-actin, into which actomyosin can be split and which acts with myosin in muscle contraction.
|actin (āk'tĭn) Pronunciation Key
A protein found in all eukaryotic cells, forming filaments that make up a main component of the cell's supporting matrix or cytoskeleton. Actin and the protein myosin together make up the contractile units (called sarcomeres) of skeletal muscle fibers.