Assuntos
Receptor fas/metabolismo , Proteína Reguladora de Apoptosis Semelhante a CASP8 e FADD/química , Proteína Reguladora de Apoptosis Semelhante a CASP8 e FADD/metabolismo , Caspases/metabolismo , Morte Celular , Proteínas Adaptadoras de Sinalização de Receptores de Domínio de Morte/metabolismo , Células HeLa , Humanos , NF-kappa B/metabolismo , Transdução de SinaisRESUMO
This study explores the dilemma in cellular signaling that triggering of CD95 (Fas/APO-1) in some situations results in cell death and in others leads to the activation of NF-kappaB. We established an integrated kinetic mathematical model for CD95-mediated apoptotic and NF-kappaB signaling. Systematic model reduction resulted in a surprisingly simple model well approximating experimentally observed dynamics. The model postulates a new link between c-FLIP(L) cleavage in the death-inducing signaling complex (DISC) and the NF-kappaB pathway. We validated experimentally that CD95 stimulation resulted in an interaction of p43-FLIP with the IKK complex followed by its activation. Furthermore, we showed that the apoptotic and NF-kappaB pathways diverge already at the DISC. Model and experimental analysis of DISC formation showed that a subtle balance of c-FLIP(L) and procaspase-8 determines life/death decisions in a nonlinear manner. We present an integrated model describing the complex dynamics of CD95-mediated apoptosis and NF-kappaB signaling.
