The involvement of PKC in the stimulus-induced up-regulation of LAT expression.

Jurkat T cells were pretreated with the indicated concentrations of the PKC inhibitors Ro-31-8220 (A and C, lanes 3 and 4) or H-7 RPMI-5% FCS (B and D, lanes 3 and 4) for 2 hours at 37°C and then stimulated in the continuous presence of inhibitors with RPMI-5% FCS containing 1 μg/mL of anti-CD3 mAb (A and B) or RPMI-5% FCS containing 1 ng/mL of PMA (C and D) for 16 hours at 37°C. After incubation, the cells were immediately lysed with boiling 2× SDS-PAGE sample buffer. Proteins in WCL were separated by SDS-PAGE and then transferred to membranes and immunoblotted with anti-LAT mAb or anti-Csk Ab. This experiment was repeated 3 times with similar results.