Actinemyosineinteractie

Actinemyosineinteractie is the process by which actin filaments and myosin motor proteins interact to convert chemical energy from ATP into mechanical work. This interaction is central to muscle contraction and to many cellular processes that require force generation or cargo transport, such as cell migration and cytokinesis.

Actin refers to filamentous actin (F-actin), while myosins are a family of ATP-dependent motors. In skeletal and cardiac muscle the major motor is myosin II, organized in thick filaments that interact with thin actin filaments. In non-muscle cells other myosins (for example myosin V and VI) participate in transport and organization of the cytoskeleton.

The interaction proceeds via the cross-bridge cycle. In the resting state, a myosin head bound to ADP and Pi weakly associates with actin. Release of Pi strengthens the bond and triggers the power stroke, sliding the actin filament relative to the myosin filament and generating force. Release of ADP completes the stroke, and a new ATP binds to the myosin head causing detachment from actin. ATP hydrolysis re-cocks the head, ready for another cycle. The cycle is regulated by calcium ions: in striated muscle, Ca2+ binds troponin, shifting tropomyosin on the actin filament to expose myosin-binding sites; in smooth muscle, Ca2+ acts via calmodulin to activate myosin light-chain kinase, enabling myosin-actin interaction.

Thus actinemyosineinteractie underpins both muscle contraction and diverse intracellular mechanics, with regulation tuned to tissue type and cellular context.