Cytokinetic pyrotechnics.

Cytokinesis, the final step in cell division, is dependent on formation and closure of a ring of actin filaments (F-actin) and myosin-2 which is, in turn, dependent on activation of the small GTPase, RhoA, at the cell equator. Four new papers, including two in this issue of Developmental Cell (Petronczki et al., 2007; Birkenfeld et al., 2007), provide new insights into how RhoA activation at the equator is initiated and maintained.