6533b85afe1ef96bd12b8c44
RESEARCH PRODUCT
p53 triggers apoptosis in oncogene-expressing fibroblasts by the induction of Noxa and mitochondrial Bax translocation.
Joshua C. GoldsteinUlrich MaurerNigel J. WaterhouseDouglas R. GreenMartin SchulerF. BreitenbücherS Hoffarthsubject
Fas-Associated Death Domain ProteinDown-RegulationChromosomal translocationApoptosisCytochrome c GroupMitochondrionMiceBcl-2-associated X proteinFetusDownregulation and upregulationProto-Oncogene ProteinsAnimalsFADDEnzyme InhibitorsMolecular BiologyCells CulturedAdaptor Proteins Signal Transducingbcl-2-Associated X ProteinMice KnockoutbiologyOncogeneChemistryCytochrome cCell BiologyFibroblastsMolecular biologyCell biologyMitochondriaProtein TransportGene Expression RegulationProto-Oncogene Proteins c-bcl-2ApoptosisCaspasesbiology.proteinTumor Suppressor Protein p53Carrier Proteinsdescription
The mechanism of p53-dependent apoptosis is still only partly defined. Using early-passage embryonic fibroblasts (MEF) from wild-type (wt), p53(-/-) and bax(-/-) mice, we observe a p53-dependent translocation of Bax to the mitochondria and a release of mitochondrial Cytochrome c during stress-induced apoptosis. These events proceed independent of zVAD-inhibitable caspase activation, are not prevented by dominant negative FADD (DN-FADD), but are negatively regulated by Mdm-2. Bcl-x(L) expression prevents the release of mitochondrial Cytochrome c and apoptosis, but not Bax translocation. At a single-cell level, enforced expression of p53 is sufficient to induce Bax translocation and Cytochrome c release. Real-time RT-PCR analysis reveals a significant induction of RNA expression of Noxa and Bax in p53(+/+), but not in p53(-/-) MEF. Noxa protein expression becomes detectable prior to Bax translocation, and downregulation of endogenous Noxa by RNA interference protects wt MEF against p53-dependent apoptosis. Hence, in oncogene-expressing MEF p53 induces apoptosis by BH3 protein-dependent caspase activation.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2003-04-30 | Cell death and differentiation |