Figure 1. Multiple stages of cytokinesis.
Three populations of microtubules first specify the site of cleavage by activating RhoA in a narrow zone between segregating chromosomes (I). Formation and activation of the actomyosin ring next leads to furrow ingression (II). The constricting furrow compacts the central spindle microtubules leading to midbody formation (III). Abscission of the furrow occurs by physically separating the cytoplasm of the daughter cells (IV).