What is the role of actin in cellular processes?

Actin is a crucial component of the cytoskeleton in eukaryotic cells, and it plays a significant role in several cellular processes, particularly cell motility and division. Actin filaments, also known as microfilaments, are dynamic structures that can polymerize and depolymerize, allowing cells to change shape and move. During cell motility, actin filaments interact with myosin to facilitate muscle contraction and movement through cellular extensions such as lamellipodia and filopodia.

In cell division, actin is vital in the formation of the contractile ring during cytokinesis, the process where the cytoplasm of a parental cell is divided into two daughter cells. This ring helps pinches the cell membrane, ultimately leading to the separation of the daughter cells.

While maintaining cell shape is also a function of actin, and its role can indirectly influence cell growth and processes related to DNA, these are not its primary functions. The most accurate description from the options given centers on actin's direct and active participation in promoting both cell movement and the mechanics of division.