what is myosin and actin in muscle contraction
Lesson Summary. In summary, myosin is a motor protein most notably involved in muscle contraction. Actin is a spherical protein that forms filaments, which are involved in muscle contraction and other important cellular processes.Tropomyosin is a long strand that loops around the actin chains in the thin filament.Troponin is a protein that helps hold tropomyosin in place on the actin filament.For a muscle contraction to occur, troponin and tropomyosin must be moved to reveal the myosin-binding sites. Calcium triggers movement of these proteins. When calcium binds to troponin, the shape of the troponin molecule changes.esson Summary. In summary, myosin is a motor protein most notably involved in muscle contraction. Actin is a spherical protein that forms filaments, which are involved in muscle contraction and other important cellular processes.