Related Experiment Videos
Jafrac2 is an IAP antagonist that promotes cell death by liberating Dronc from DIAP1
Tencho Tenev1, Anna Zachariou, Rebecca Wilson
1The Breakthrough Toby Robins Breast Cancer Research, Institute of Cancer Research, Chester Beatty Laboratories, Fulham Road, London SW3 6JB, UK.
Abstract:
Members of the Inhibitor of Apoptosis Protein (IAP) family are essential for cell survival in Drosophila and appear to neutralize the cell death machinery by binding to and ubiquitylating pro-apoptotic caspases. Cell death is triggered when "Reaper-like" proteins bind to IAPs and liberate caspases from IAPs. We have identified the thioredoxin peroxidase Jafrac2 as an IAP-interacting protein in Drosophila cells that harbours a conserved N-terminal IAP-binding motif. In healthy cells, Jafrac2 resides in the endoplasmic reticulum but is rapidly released into the cytosol following induction of apoptosis. Mature Jafrac2 interacts genetically and biochemically with DIAP1 and promotes cell death in tissue culture cells and the Drosophila developing eye. In common with Rpr, Jafrac2-mediated cell death is contingent on DIAP1 binding because mutations that abolish the Jafrac2-DIAP1 interaction suppress the eye phenotype caused by Jafrac2 expression. We show that Jafrac2 displaces Dronc from DIAP1 by competing with Dronc for the binding of DIAP1, consistent with the idea that Jafrac2 triggers cell death by liberating Dronc from DIAP1-mediated inhibition.
Insights
The thioredoxin peroxidase Jafrac2 binds to Inhibitor of Apoptosis Proteins (IAPs) in Drosophila, promoting cell death by releasing pro-apoptotic caspases. This interaction is crucial for apoptosis, highlighting Jafrac2
Area of Science:
- Cell Biology
- Molecular Biology
- Genetics
Background:
- Inhibitor of Apoptosis Proteins (IAPs) are key regulators of cell survival, inhibiting apoptosis by targeting pro-apoptotic caspases.
- Apoptosis is triggered by "Reaper-like" proteins that bind IAPs, liberating caspases.
- Understanding IAP-interacting proteins is crucial for deciphering apoptosis regulation.
Purpose of the Study:
- To identify novel IAP-interacting proteins involved in apoptosis regulation in Drosophila.
- To characterize the role of the thioredoxin peroxidase Jafrac2 in IAP-mediated cell death.
- To elucidate the mechanism by which Jafrac2 influences caspase activity.
Main Methods:
- Biochemical assays to confirm Jafrac2-DIAP1 interaction.
- Genetic analysis in Drosophila tissue culture and developing eye models.
- Mutation analysis to assess the impact of Jafrac2-DIAP1 binding disruption.
Main Results:
- Jafrac2 was identified as an IAP-binding protein in Drosophila cells, possessing a conserved N-terminal IAP-binding motif.
- Jafrac2 interacts with DIAP1 and promotes apoptosis in cell culture and the Drosophila eye.
- Jafrac2 displaces Dronc from DIAP1, indicating it liberates caspases from IAP inhibition.
Conclusions:
- Jafrac2 is a novel mediator of apoptosis in Drosophila, functioning by interacting with DIAP1.
- The interaction between Jafrac2 and DIAP1 is essential for Jafrac2-induced cell death.
- Jafrac2's mechanism involves liberating Dronc from DIAP1, thereby activating the apoptotic pathway.