PRO-APOPTOTIC AND ANTI-APOPTOTIC EFFECTS OF K-CELLS( IN HELA)

The present study determined the effects of osmotic stress induced by sorbitol and KCl on apoptosis, Sorbitol induced apoptosis, activated t he mitogen-activated protein kinase (MAPK) family and stimulated accum ulation of cytosolic cytochrome c and procaspase-3 cleavage, KCl (0.2 M) also activated the MAPKs and induced cytosolic cytochrome c accumul ation but did not induce procaspase-3 cleavage or apoptosis and was pr otective against sorbitol-induced apoptosis, However, when cells were exposed to KCI for 1 h, washed and returned to isotonic medium, caspas e-3 was rapidly cleaved and apoptosis induced, We conclude that hypero smotic KCl initiates early events in apoptosis but blocks caspase-3 ac tivation by preventing the loss of intracellular K+, (C) 1998 Federati on of European Biochemical Societies.