Dosage of Tat-dn-H-Ras affects IL-5–stimulated ERK 1 and ERK 2 activation.

(A) Human blood eosinophils were incubated with various concentrations of Tat-dn-H-Ras for 30 minutes and then stimulated for 7 minutes with 1 nM IL-5. Resultant cell lysates were resolved by SDS-PAGE and processed for immunoblot analysis using anti-active MAPK antibodies. (B) Cell lysates from panel A were also probed with anti-ERK 1 and ERK 2 antibodies to demonstrate equivalent masses of ERK 1 and ERK 2 in all samples. (C) The same experiment described for panel A was performed with concentrations of Tat-dn-H-Ras that were suboptimal for inhibiting ERK activation. These immunoblots are representative of 8 experiments.