FIGURE 1.

Septin‐depleted cells undergo significantly less apoptosis. (a) HeLa cells were transfected for 72 hr with control (CTRL) siRNA or a siRNA targeting SEPT7. Effect of siRNA on SEPT7 expression. A representative Western blot of HeLa cell lysates is shown. GAPDH was used as a loading control. (b) Impact of siRNA targeting SEPT7 on viability of HeLa cells in (i) untreated or (ii) STS‐treated conditions. Cell viability is measured using MTT assays as described in Materials and Methods. Data are mean ± SEM from three independent experiments. **p = .0069 by two‐tailed Student's t test. (c) HeLa cells were transfected for 72 hr with control (CTRL) siRNA or a siRNA targeting SEPT2. Effect of siRNA on SEPT2 expression. A representative Western blot of HeLa cell lysates is shown. (d) Impact of siRNA targeting SEPT2 on viability of HeLa cells in (i) untreated or (ii) STS‐treated conditions. Cell viability is measured using MTT assays as described in Materials and Methods. Data are mean ± SEM from three independent experiments. ***p = .0004 by two‐tailed Student's t test. (e) Control and SEPT7‐depleted cells were treated with DMSO or 1 μM STS or 500 μM ETP for 10 hr and labeled with Alexa488‐Annexin V (Annexin V) and Hoechst. Representative widefield microscopy images showing Annexin V in green and Hoechst in blue. Scale bar = 100 μm. (f) The % of Annexin V positive cells is calculated in Fiji by dividing the number of cells that displayed Annexin V labeling by the total number of cells identified by nuclear Hoechst labeling, then multiplying by 100. Each bar represents the mean % ± SEM from three independent experiments (a minimum of 1,000 cells were counted per condition separated in three independent experiments). ****p < .0001by two‐way ANOVA.