Figure 7. Cdc42 depletion affects midbody trafficking of Rab8a vesicle and cytokinesis.

(A) Western blots confirmed Cdc42 knockdown by siRNA in Hela cells. (B and C) Live cell imaging showed that Rab8a-GFP (green) trafficked to the mcherry-tubulin–labeled midbody (red) during early cytokinesis in control cells but not in Cdc42-depleted cells. Arrows in B indicate enriched Rab8a at control midbody. Arrowhead in C indicates less Rab8a protein at midbody of Cdc42-depleted cells. (D and E) Rab8a-GFP localizes to the midbody (arrows in D) during late cytokinesis in control cells but not in Cdc42-depleted cells (arrowheads in E). (F) Quantification of cytokinesis in cells transfected with control siRNA, Cdc42 siRNA (Cdc42KD), and cells treated with 7 μM CASIN. (G) FACS cell cycle analyses of CASIN-treated cells showed accumulation at the G₂/M phase. (H) Western blots confirmed Cdc42 knockdown in Caco2 cells by a lentiviral shRNA particle. (I and J) Rab8a and Pkcζ staining for control and Cdc42 knockdown Caco2 cysts. Arrowheads in J indicate large vacuoles where Rab8a was localized. Scale bars: 10 μm. *P < 0.05; **P < 0.01.