Figure 5.
Conditional expression of PAC1 does not provide cytoprotection against UV-induced apoptosis. (A) U937 cells were transfected with hMTIIa-PAC1 and a stable cell line derived by selection in the presence of hygromycin B. Cells were treated for 4 h with 1 μM CdSO4 and PAC1 expression determined by Western blot analysis. (B) Cells were pretreated with 1 μM CdSO4 and then treated with either PMA (200 nM) (Upper) or UV radiation (200 J/m2) (Lower). After 30 min, cell extracts were analyzed for ERK2 phosphorylation (Upper), or SAPK activity (Lower) as described in Materials and Methods. (C) Cells were pretreated with 1 μM CdSO4 for 4 h and exposed to UV irradiation (200 J/m2) as indicated. DNA fragmentation was analyzed 8 h postirradiation as described (33).