Western Blot: Jurkat cells were incubated without (lanes 1 & 3) or with (lanes 2 & 4) monoclonal antibody that binds Jurkat T-cell receptors. Lysates were probed with anti-phospho-LAT (Tyr191) (2ug/ml) (lanes 1 & 2, or anti-LAT (1ug/ml) (lanes 3 & 4).