CTL-mediated killing is sensitive to dominant-negative dynamin. HeLa-DynWT or DN cells were treated to suppress (+tet) or induce (–tet) overexpression from the transfected dynamin cDNA. Cells were treated with CTLs (1:1 E/T ratio), with or without EGTA, concanamycin A (CMA), or neutralizing anti-Fas (nαFas). All assays were quantified by flow cytometry. (A) Caspase activation was assessed after 2 hours by labeling with M30 mAb. (B) Loss of ΔΨ_m was assessed after 2 hours by monitoring loss of TMRE labeling. (C) DNA oligomerization was assessed after 4 hours by TUNEL. (D) Representative flow cytometry data of hCTLs, or HeLa-DynDN ± tet ± hCTLs, as monitored by M30 mAb labeling. The mean ± SD of 4 (A,C) or 3 (B) independent experiments is shown (*.05 < P < .01; **.001 < P < .01; ***P < .001).