IgE alone stimulates phosphorylation of ERK, p38 and PI3K in mast cells.

Mast cells were treated with IgE alone at 5 µg/mL for the indicated times. Total cell lysates (50 µg) were subjected to Western blotting analysis using anti-phospho antibodies specific to ERK1/2 (pERK1/2), p38 (pp38) or PI3K (pPI3K). The same blots were reprobed with respective antibodies that recognize these signaling molecules, irrespective of the phosphorylation states. Results are representative of 3 independent experiments.