Cdc42 prevents apoptosis as induced by CTLs of different specificities or cytotoxic drugs. (A) cA2K^b-Cdc42 (■) or cA2K^b-control MEFs (□) were loaded with different peptide concentrations representing HLA-A*0201–restricted influenza (top panel) and human p53 (bottom panel) epitopes, followed by coincubation with A2 Flu CTLs (top panel; E/T = 30) or A2 p53 CTLs (bottom panel; E/T = 15). Mean values plus or minus SD of 5-hour ⁵¹Cr release assays. (B) cA2K^b-Cdc42 (■) or cA2K^b-control MEFs (□) were treated for 24 hours with staurosporine (left) or etoposide (right). Cells with maintained Δψ_m (TMRE⁺; top panel) or apoptotic DNA fragmentation (sub-G₁; bottom panels) were quantified by flow cytometry following staining with the fluorescent dyes TMRE or propidium iodide, respectively. Mean values plus or minus SD of 3 repetitions are shown.