Figure 1.

Rho family GTPases play distinct roles during cytokinesis. Cdc42 (green) is activated at the assembled actomyosin ring (red) and this promotes onset of ring constriction and septum formation. Rho1 (blue) is activated at the division site to promote septum synthesis. The precise timing of initiation of Rho1 activation is not known. After the septum forms, Rho3 (yellow) and Rho4 (orange) localize to the division site at the outer rim of the septum barrier to promote delivery of the septum digesting glucanases. Digestion of the primary septum leads to cell separation.