Antiapoptotic effect of TAT-Pim1(wt) depends on p38 MAPK activation. Basophils were incubated with the buffer (control), or with TAT-Pim1(wt) and TAT-Pim1(KD) for 1 hour, and then wortmannin (100 nM) or SB202190 (10 μM) was added to cell cultures for 24 hours. (A) Cell apoptosis was determined by annexin V–FITC staining and subsequent flow cytometry. Apoptotic cells are shown as percentage of annexin V–positive cells. Data are shown as mean plus SEM from 3 experiments. *P < .05, **P < .01, for the comparison of TAT-Pim1 versus medium control within the groups, by one-way ANOVA. (B) Activated caspase 3, procaspase 3, and TAT-pim1 fusion proteins as well as (C) phospho-and total of p38 MARK were detected by immunblotting using specific antibodies. β-Actin was used as loading control. Fold changes of caspase 3 activity and p38 MAPK phosphorylation were calculated as described in the legends to Figures 4 and 5.