Fig. 2. PMA-mediated signaling in PMA-resistant K562 cells. The effect of PMA treatment on signal transduction pathways in both wild-type and PMA-resistant K562 cells was studied by measuring the levels of PKC (A) or Pyk2 (B) or the activation of the MAPK pathway (C and D). Data presented in D depict the C1 clone. Samples were processed as described in "Materials and Methods."