CD95 (Fas/APO-1) induces an increased phosphatidylserine synthesis that precedes its externalization during programmed cell death.
CD95 (Fas, APO-1)-induced programmed cell death (apoptosis) in T cell lines is accompanied by a rapid flip-flop of phosphatidylserine (PtdSer). Externalization of this phospholipid has been previously recognized as one of the early detectable events of cells undergoing apoptosis. We show here that CD95 induces a rapid (detectable at time < 15 min), strong (2.5-fold) but transitory neosynthesis of PtdSer in the Jurkat cell line that precedes its externalization. PtdSer decarboxylation, a mitochondrial specific process, was strongly inhibited by CD95 suggesting that changes in mitochondrial activity take place in the early events of Fas-induced apoptosis and participate in the increased PtdSer synthesis observed. In cells undergoing apoptosis, newly synthesized PtdSer first exposed at the cell surface was in part shed with CD95-induced plasma membrane vesicles, a process that likely explains the transitory effect observed.
INSERM U343, Hôpital de l'Archet, Nice, France. aussel@unice.fr
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Aussel
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Pelassy
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JP
Breittmayer
D000911:Antibodies, Monoclonal; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D001692:Biological Transport; D002118:Calcium / Q000378:metabolism; D003653:Decarboxylation / Q000187:drug effects; D006801:Humans; D019169:Jurkat Cells; D008564:Membrane Potentials; D010718:Phosphatidylserines / Q000819:agonists / Q000096:biosynthesis* / Q000378:metabolism; D019014:fas Receptor / Q000378:metabolism / Q000494:pharmacology*
D000911:Antibodies, Monoclonal; D010718:Phosphatidylserines; D019014:fas Receptor; D002118:Calcium