PI3K activity is stimulated by IL-1 and inhibited by LY294,002. Where indicated, HepG2 cells were incubated with 20 μM LY294,002 for 30 min prior to stimulation with IL-1β for the indicated time periods. PI3K activity was measured as the phosphorylation of phosphatidylinositol(4,5)P2 yielding phosphatidylinositol(3,4,5)P3 [PI(3,4,5)P3]. −Ab, no anti-PY20.