Skip to main content
. 2009 May 26;7(5):e1000110. doi: 10.1371/journal.pbio.1000110

Figure 7. Ectopic cleavage furrowing during forced mitotic exit requires Prc1.

Figure 7

(A) HeLa cells were either mock transfected (control) or transfected with siRNA to deplete the indicated protein and synchronized in prometaphase with nocodazole. Ectopic cleavage furrow formation and RhoA activation were induced with addition of 22.5 µM purvalanol A for 30 min. Cells were fixed and stained with antibodies to RhoA, and DNA was stained with DAPI. Percentages of cells undergoing ectopic cleavage furrow formation were determined as a function of RhoA cortical recruitment in 100 cells. (B) Proposed model. At the central spindle, microtubules are bundled through the combined efforts of the centralspindlin complex and the MAP Prc1. Factor X, which could be Prc1, Mklp2, centralspindlin, or an unknown factor, recruits Plk1 to the central spindle through association with its PBD, freeing the kinase domain to phosphorylate substrates at the central spindle (e.g., HsCyk-4, Ect2). Plk1 phosphorylation of HsCyk-4 is not sufficient for Ect2 recruitment to the central spindle, but requires other Plk1-dependent processes, at least one of which may be the relief of Ect2 autoinhibition. GAP, HsCyk-4; GEF, Ect2.