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Isolated Extracellular Domain of DR5 is a Potential inhibitor of Apoptosis
Author(s) -
Vunnam Nagamani,
Sachs Jonathan N
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.647.7
Subject(s) - apoptosis , ligand (biochemistry) , receptor , death domain , tumor necrosis factor alpha , microbiology and biotechnology , programmed cell death , chemistry , signal transduction , biology , biochemistry , immunology
In recent years, there has been a great interest in pre‐ligand assembly of tumor necrosis factor receptors (TNFRs). TNF‐receptor superfamily plays a major role in regulation of apoptosis. Recent studies suggest that disrupting the pre‐ligand assembly of TNFRs maybe a useful approach for the treatment of TNF‐disorders like rheumatoid arthritis. Thus, strategies for the manipulation of pre‐ligand assembly of TNFRs maybe valuable in prevention and mediation of TNF‐receptor related ailments. In the current study, we targeted the pre‐ligand assembly of death receptor 5 (DR5) to inhibit the apoptosis induced by its cognate ligand. DR5 is a pro‐apoptotic TNF‐receptor protein with a N‐terminal extracellular domain (ECD), a transmembrane domain, and a cytoplasmic death domain, which is crucial for initiation of death signaling upon binding of TNF‐related apoptosis inducing ligand (TRAIL). We hypothesized that ECD, which does not have the death domain, of DR5 could prevent the TRAIL‐induced apoptosis by disrupting the pre‐ligand assembly of endogenous‐DR5 (eDR5) and forming the death‐inhibitory complex with it. To test this hypothesis we first determined the interactions between isolated ECD, eDR5 and TRAIL by using electrophoresis, spectroscopy, FRET and Coimmunoprecipitation (CoIP) studies. These studies show that isolated ECD interacts with both TRAIL and eDR5 and does not significantly influence the eDR5‐TRAIL interactions. We further investigated the effect of ECD on TRAIL‐induced apoptosis by using cell culture studies. Here, we show that ECD inhibits the TRAIL‐induced apoptosis by disrupting the pre‐ligand assembly of eDR5, which is required for induction of death signaling, and forming the anti‐apoptotic complex with eDR5. In summary, our biophysical and cell culture data suggest that the ECD is a potential inhibitor of apoptosis and may have a prospective therapeutic value for the treatment of TNF‐receptor related disorders. Support or Funding Information This work was supported by National Institutes of Health Grant GM107175‐02