Caspase 3 activation is controlled by a sequence located in the N-terminus of its large subunit.

We report that the induction and completion of the apoptotic program is delayed in a doxorubicin-resistant cell line (HL60/ADR). This hindrance to cell death occurred downstream of the multidrug-resistant protein (mrp), a transmembrane transporter. In vitro studies showed that these cells were incapable of correctly activating procaspase 3 (pC3), the main executioner of apoptosis.