Expression of TCL1 in primary transformed and untransformed T lymphocytes inhibits PKCθ and ERK activation. (A) Human normal PBMCs and T-PLL cells overexpressing TCL1 (TP22 on left and TP15 on right) were stimulated with PMA or UCHT1 at different times as indicated in the figure. PKCθ phosphorylation (top), ERK phosphorylation (2 exposures are shown to visualize the weaker signal in UCHT1 stimulation) (middle), and TCL1 expression (bottom) were determined by Western blotting. Total ERK and PKCθ expression were used as loading controls. A representative experiment of the 2 performed is shown. (B) PBMCs were transduced with pCDH1 (PBMC-(C) and pCDH1-TCL1 (PBMC-TCL1) vectors and stimulated with UCHT1 or PMA at the times indicated in the figure. ERK and PKCθ phosphorylation, and TCL1 expression were determined by Western blotting. Total ERK and β-actin expression were used as loading control. A representative experiment of 2 performed is shown.