- a globulin that is present in muscle plasma and that in connection with myosin plays an important role in muscle contraction.
- variant of actino- before a vowel: actinism.
- a protein that participates in many kinds of cell movement, including muscle contraction, during which it interacts with filaments of a second protein, myosin
- 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.
- 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.