Stimulation of PSI-mediated apoptosis is delayed by overexpression of Bcl-xL and Flag-crmA.

<p>(A) Whole-cell lysates prepared from K562 cells (ATCC) stably expressing either Flag-crmA or Bcl-xL was subjected to Western blot analysis using antibodies reacting against Bcl-xL or the Flag epitope. ß-tubulin: loading control. (B) Control, Flag-crmA and Bcl-xL overexpressing K562 cells were exposed for 24 h to 20 nM PSI and 20 µM salubrinal as indicated after which apoptosis induction was determined as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0004161#s2" target="_blank">Materials and Methods</a> (mean±SD of 3 determinations).