Required for cytokinesis. Essential for the structural integrity of the cleavage furrow and for completion of cleavage furrow ingression (PubMed:12479805). Plays a role in bleb assembly during metaphase and anaphase of mitosis. May play a significant role in podocyte cell migration (By similarity). Interacts with and bundles F-actin (PubMed:15496454, PubMed:12479805). Interacts with the non-muscle myosin II heavy chains myh9 and myh10, and these interactions may be enhanced by the phosphorylation of myosin II regulatory light chain by mylk (PubMed:15496454). Mainly found in the nucleus during interphase. Colocalizes with cortical F-actin upon nuclear envelope breakdown in mitosis and subsequently concentrates in the area of the prospective contractile ring in anaphase.