PI(4,5)P2 and PI(3,4,5)P3 differentially regulate apoptosis. LLC-PK1 cells were maintained on permeable supports, and pre-treated by incorporation of metabolically stable diC8-PI(4,5)P2 or diC8-PI(3,4,5)P3. Cells were then induced to undergo apoptosis with staurosporine (STS, 1 μm, 5 h, in panel A) or cisplatin (25 μm, 18 h, 37 °C, in panel B). Apoptosis was quantified by TUNEL. Note the difference in y-axis scale between histograms. *, p < 0.05 compared with staurosporine-only or cisplatin-only groups by analysis of variance.