Final answer:
The interaction with motor proteins such as myosin and the ATP-powered polymerization and motor activity are major influences on the organization and behavior of actin filaments in cells, impacting cell division, muscle contraction, and cell motility.
Step-by-step explanation:
A major influence in determining the organization and behavior of actin filaments inside cells is the interaction with motor proteins, particularly myosin. Actin and myosin work together to enable various cellular events such as cell division, muscle contraction, and cytoplasmic streaming. The dynamics of actin filament-based motility are driven by ATP hydrolysis, which powers both the polymerization of actin and the motor activity of myosin. Contractile networks and bundles of actin within the cells are under tension due to the contractile activity of myosin motors, which generate internal forces through a non-equilibrium process involving ATP hydrolysis. These internal forces contribute to cellular movements and the structural integrity of the cell. Actin can exist both as a more rigid, polymerized gel form, which grants stability to the cell and as a fluid, unpolymerized soluble form, which allows for rapid changes in cell shape and movement.