Phosphatidyl serine exposure during apoptosis precedes release of cytochrome c and decrease in mitochondrial transmembrane potential

Time kinetics of phosphatidyl serine (PS) exposure were compared to other a poptotic parameters following different apoptotic stimuli, Our data indicat e that anti-Fas treatment of L929sAhFas cells results in rapid exposure of PS, which precedes decrease in mitochondrial transmembrane potential (Delta Psi(m)) and release of cytochrome c, indicating that PS exposure occurs in dependently of these mitochondrial events. Also during TNF-, etoposide- or staurosporine-mediated apoptosis in PC60 RI/RII cells, PS-positive cells we re observed before they had a decreased Delta Psi(m). However, during growt h factor depletion-induced death of 32D cells, both phenomena seemed to occ ur at the same time. (C) 2000 Federation of European Biochemical Societies.