51. Structural and Functional Studies of the RBPJ-SHARP Complex Reveal a Conserved Corepressor Binding Site
- Author
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Tilman Borggrefe, Leiling Pan, Bradley D. VanderWielen, Zhenyu Yuan, Franz Oswald, Kerstin Hein, Rhett A. Kovall, Aleksandra Turkiewicz, Courtney E. Collins, and Benedetto Daniele Giaimo
- Subjects
0301 basic medicine ,Transcription, Genetic ,Notch signaling pathway ,Repressor ,General Biochemistry, Genetics and Molecular Biology ,Article ,03 medical and health sciences ,Mice ,0302 clinical medicine ,Transcription (biology) ,Coactivator ,Transcriptional regulation ,Animals ,Humans ,Protein Structure, Quaternary ,Transcription factor ,Binding Sites ,Receptors, Notch ,Chemistry ,RBPJ ,RNA-Binding Proteins ,DNA ,3. Good health ,Cell biology ,DNA-Binding Proteins ,030104 developmental biology ,HEK293 Cells ,Immunoglobulin J Recombination Signal Sequence-Binding Protein ,Multiprotein Complexes ,Corepressor ,030217 neurology & neurosurgery ,HeLa Cells ,Signal Transduction - Abstract
SUMMARY Notch is a conserved signaling pathway that is essential for metazoan development and homeostasis; dysregulated signaling underlies the pathophysiology of numerous human diseases. Receptor-ligand interactions result in gene expression changes, which are regulated by the transcription factor RBPJ. RBPJ forms a complex with the intracellular domain of the Notch receptor and the coactivator Mastermind to activate transcription, but it can also function as a repressor by interacting with corepressor proteins. Here, we determine the structure of RBPJ bound to the corepressor SHARP and DNA, revealing its mode of binding to RBPJ. We tested structure-based mutants in biophysical and biochemical-cellular as-says to characterize the role of RBPJ as a repressor, clearly demonstrating that RBPJ mutants deficient for SHARP binding are incapable of repressing transcription of genes responsive to Notch signaling in cells. Altogether, our structure-function studies provide significant insights into the repressor function of RBPJ., Graphical Abstract, In Brief Yuan et al. determine the X-ray structure of the corepressor SHARP bound to RBPJ, the nuclear effector of the Notch pathway. The structure-function analysis provides insights into corepressor binding to RBPJ and how RBPJ functions as a repressor of transcription of Notch target genes.
- Published
- 2019