Figure 12.

PI-PLC is downstream of PI3K in the same signaling pathway to constitutive macropinocytosis. In situ phospholipase activity was determined by intracellular IP3 levels with the use of a competitive radioligand-binding assay. The indicated cells were preincubated at 37°C for 1 h with DMEM without serum supplemented with the indicated concentrations of inhibitors. All values are means ± SEM of four dishes pooled from two separate experiments.