The substitution of the C-terminus of bax by that of bcl-xL does not affect its subcellular localization but abrogates its pro-apoptotic properties

The interaction of the anti-apoptotic members of the Bcl-2 family with mito chondria, through their hydrophobic C-terminus, has been proposed to play a crucial role in the execution phase of apoptosis, We report here that a su bstitution of the C-terminal end of pro-apoptotic bax by that of antiopopto tic bcl-xL (baxCxL) does not modify its association with mitochondria in hu man and rat cells or in Saccharomyces cerevisiae. In addition, while bax se nsitizes these cells to apoptotic stimuli, the construct baxCxL does not af fect the apoptotic response in transfected cells. These results suggest tha t the C-terminus of bax plays an important role in apoptosis independently of its membrane addressing/targeting mechanism. (C) 2000 Federation of Euro pean Biochemical Societies. Published by Elsevier Science B.V. All rights r eserved.