Depletion of Skittles and Pten destabilizes the mitotic cortex. (A) Schematic representation of phosphoinositide (PI) pathways. Each of 31 enzymes was individually inactivated by dsRNA, and its influence on cortical stability was analyzed by time-lapse imaging of α-Tubulin-GFP cells undergoing mitosis (n > 100 cells per condition). (B) The graph plots the percentage of cells with mitotic blebbing in control condition and after inhibition of CG10260, Pten, or Skittles. (C) Cellular levels of PI(4,5)P₂ in controls and in cells after depletion of CG10260, Pten, or Skittles, as measured by biochemical assays. An arbitrary value of 1 was attributed to levels observed in wild-type cells. (D) Influence of Pten and Skittles on PI(4,5)P₂ levels at the cortex of S2 cells. Pictures show GFP-Tubby cells in control conditions and after Pten or Skittles depletion. The graph plots the percentage of cells showing membrane association of GFP-Tubby in each condition. Error bars represent SD. Bars, 10 µm.