8dpx | pdb_00008dpx
Preligand association structure of DR5
Structural highlights
DiseaseTR10B_HUMAN Defects in TNFRSF10B may be a cause of head and neck squamous cell carcinomas (HNSCC) [MIM:275355; also known as squamous cell carcinoma of the head and neck. FunctionTR10B_HUMAN Receptor for the cytotoxic ligand TNFSF10/TRAIL. The adapter molecule FADD recruits caspase-8 to the activated receptor. The resulting death-inducing signaling complex (DISC) performs caspase-8 proteolytic activation which initiates the subsequent cascade of caspases (aspartate-specific cysteine proteases) mediating apoptosis. Promotes the activation of NF-kappa-B. Essential for ER stress-induced apoptosis.[1] Publication Abstract from PubMedMembers of the tumor necrosis factor receptor superfamily (TNFRSF) are important therapeutic targets that can be activated to induce death of cancer cells or stimulate proliferation of immune cells. Although it has long been implicated that these receptors assemble preligand associated states that are required for dominant interference in human disease, such states have so far eluded structural characterization. Here, we find that the ectodomain of death receptor 5 (DR5-ECD), a representative member of TNFRSF, can specifically self-associate when anchored to lipid bilayer, and we report this self-association structure determined by nuclear magnetic resonance (NMR). Unexpectedly, two non-overlapping interaction interfaces are identified that could propagate to higher-order clusters. Structure-guided mutagenesis indicates that the observed preligand association structure is represented on DR5-expressing cells. The DR5 preligand association serves an autoinhibitory role as single-domain antibodies (sdAbs) that partially dissociate the preligand cluster can sensitize the receptor to its ligand TRAIL and even induce substantial receptor signaling in the absence of TRAIL. Unlike most agonistic antibodies that require multivalent binding to aggregate receptors for activation, these agonistic sdAbs are monovalent and act specifically on an oligomeric, autoinhibitory configuration of the receptor. Our data indicate that receptors such as DR5 can form structurally defined preclusters incompatible with signaling and that true agonists should disrupt the preligand cluster while converting it to signaling-productive cluster. This mechanism enhances our understanding of a long-standing question in TNFRSF signaling and suggests a new opportunity for developing agonistic molecules by targeting receptor preligand clustering. Autoinhibitory structure of preligand association state implicates a new strategy to attain effective DR5 receptor activation.,Du G, Zhao L, Zheng Y, Belfetmi A, Cai T, Xu B, Heyninck K, Van Den Heede K, Buyse MA, Fontana P, Bowman M, Lin LL, Wu H, Chou JJ Cell Res. 2023 Feb;33(2):131-146. doi: 10.1038/s41422-022-00755-2. Epub 2023 Jan , 6. PMID:36604598[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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