DMS potentiates cyt c and Smac/DIABLO release and caspase-3 activation induced by cell surface death receptors.

Jurkat (A) or U937 cells (B) were preincubated with 5 μM DMS for 15 minutes and then treated for an additional 3 hours without or with 50 ng/mL anti-Fas antibody or for 5 hours with 50 ng/mL TNF-α, respectively. Cytosolic extracts were subjected to 15% SDS-PAGE and immunoblotted with anti-cyt c, anti-Smac/DIABLO, and anti-COX II, as described in Figure 1. Caspase-3–like activity in duplicate extracts from Jurkat (C) or U937 cells (D) was measured with the fluorogenic substrate Ac-DEVD-AMC. Results are means of 3 independent experiments.