Final answer:
Actin is a protein involved in maintaining cellular shape, enabling cell movement and division, and forming cell-to-cell or cell-to-matrix junctions.
Step-by-step explanation:
Actin is a protein involved in various motile processes within cells. It helps in maintaining cellular shape and allows movement of certain cells by forming cytoplasmic extensions or contraction of actin fibers. Actin is also involved in cell-to-cell or cell-to-matrix junctions.
It enables cell movement, cytoplasmic streaming, and helps in muscle contraction. Additionally, actin plays a crucial role during cell division by creating a cleavage furrow that splits the cell into two new cells.