Cell cytoskeleton research, artwork. The role of actin in animal cells is shown at left, while a new method of studying actin is shown at right. The cell shown here is a macrophage that will engulf and destroy the surrounding bacteria (rod-shaped, smaller cells). Actin forms long filaments below the surface of the cell, giving it structure and stability. New actin growth helps cells like macrophages to move and form protrusions (lower centre). At right, actin growth has pushed up the cantilever of an atomic force microscope (AFM), enabling researchers to use AFMs to study aspects of actin growth.