Figure 11.

Depletion of Mob1A affects the organization of centralspindlin during anaphase. (A) RPE1 cells transfected with control- or Mob1A/1B siRNAs were probed for MKLP1 or MgcRacGAP and counterstained with INCENP or Aurora B, respectively. Bar, 10 μm. (B) Control- or Mob1A/1B-depleted cells were processed for tubulin and MKLP1 localization, and the zone of MKLP1 was measured as a function of spindle length for 200 cells per condition. For each cell, the width of the MKLP1 signal at the midzone was measured, along with the length of the spindle and width of central spindle. Lines of correlation that best fit the scatter plot data are depicted for control (black line) and Mob1A/1B-depleted cells (red line). As shown in the graph, the MKLP1 zone narrowed as anaphase progressed for both control- and Mob1-depleted cells. However, in contrast to controls, the zone of MKLP1 was wider in Mob1-depleted cells both early and late in anaphase. (C) Analysis of covariance was performed on the two data sets, and although there was no statistical significance in the rate of MKLP1 narrowing between control and Mob1-depleted cells (p = 0.537957) (measured by comparing the 2 slopes), there was a significant difference between the widths of the two zones as cells progressed through anaphase (p = 0.00001).