Related Experiment Videos
PED/PEA-15: an anti-apoptotic molecule that regulates FAS/TNFR1-induced apoptosis
G Condorelli1, G Vigliotta, A Cafieri
1Dipartimento di Biologia e Patologia Cellulare e Molecolare L. Califano, Federico II University of Naples Medical School, Italy.
Abstract:
PED/PEA-15 is a recently cloned 15 kDa protein possessing a death effector domain (DED). In MCF-7 and HeLa cells, a fivefold overexpression of PED/PEA-15 blocked FasL and TNFalpha apoptotic effects. This effect of PED overexpression was blocked by inhibition of PKC activity. In MCF-7 and HeLa cell lysates, PED/PEA-15 co-precipitated with both FADD and FLICE. PED/PEA-15-FLICE association was inhibited by overexpression of the wild-type but not of a DED-deletion mutant of FADD. Simultaneous overexpression of PED/PEA-15 with FADD and FLICE inhibited FADD-FLICE co-precipitation by threefold. Based on cleavage of the FLICE substrate PARP, this inhibitory effect was paralleled by a threefold decline in FLICE activation in response to TNF-alpha. TNFalpha, in turn, reduces PED association with the endogenous FADD and FLICE of the cells. Thus, PED/PEA-15 is an endogenous protein inhibiting FAS and TNFR1-mediated apoptosis. At least in part, this function may involve displacement of FADD-FLICE binding through the death effector domain of PED/PEA-15.
Insights
PED/PEA-15 protein inhibits apoptosis by blocking FasL and TNFalpha signaling pathways. This protein interacts with FADD and FLICE, potentially displacing their binding to prevent cell death.
Area of Science:
- Cellular and Molecular Biology
- Apoptosis Research
- Signal Transduction
Background:
- PED/PEA-15 is a 15 kDa protein with a death effector domain (DED).
- Apoptosis can be triggered by Fas Ligand (FasL) and Tumor Necrosis Factor-alpha (TNFalpha).
- Protein interactions are crucial in regulating apoptotic pathways.
Purpose of the Study:
- To investigate the role of PED/PEA-15 in FasL and TNFalpha-mediated apoptosis.
- To elucidate the molecular mechanism by which PED/PEA-15 inhibits apoptosis.
- To determine the interaction of PED/PEA-15 with apoptotic signaling proteins.
Main Methods:
- Overexpression of PED/PEA-15 in MCF-7 and HeLa cells.
- Inhibition of Protein Kinase C (PKC) activity.
- Co-precipitation assays to study protein interactions (PED/PEA-15, FADD, FLICE).
- Analysis of PARP cleavage as a marker for apoptosis.
- Western blotting to assess protein levels and interactions.
Main Results:
- Overexpression of PED/PEA-15 blocked FasL and TNFalpha-induced apoptosis.
- Inhibition of PKC activity reversed the anti-apoptotic effect of PED/PEA-15.
- PED/PEA-15 co-precipitated with FADD and FLICE.
- PED/PEA-15 binding to FADD and FLICE inhibited FADD-FLICE complex formation and FLICE activation.
- TNFalpha treatment reduced PED/PEA-15 association with FADD and FLICE.
Conclusions:
- PED/PEA-15 is an endogenous inhibitor of FAS and TNFR1-mediated apoptosis.
- The anti-apoptotic function of PED/PEA-15 involves its death effector domain (DED) and may displace FADD-FLICE binding.
- PKC activity influences the anti-apoptotic role of PED/PEA-15.