Figure 1.

ISA-2011B inhibits phosphatidylinositol 4-phosphate 5-kinase (PIP5K)α lipid-kinase activity in primary T cells. (A) Primary T cells from healthy donors (HD) were treated for 6 h with DMSO or the indicated concentrations of ISA-2011B and then unstimulated (ctr) or stimulated for 5 min with saturating concentration of anti-CD3 (5 µg/ml) plus anti-CD28 Abs crosslinked with goat anti-mouse (20 µg/ml). PIP5K kinase assays were performed on anti-PIP5Kα immunoprecipitations and the reaction products were subjected to thin-layer chromatography followed by autoradiography (upper panel). An equal amount of cell lysate was analyzed for PIP5Kα content by Western blotting (lower panel). (B) Fold inductions were quantified by densitometric analysis and normalized to PIP5Kα levels. Bars show the mean ± SD of two experiments. Asterisks (*) indicate P < 0.05 calculated by Student’s t-test.