Download MendeleyStructural and functional studies of the EGF20-27 region reveal new features of the human Notch receptor important for optimal activation.
Bo, Z., Rowntree, T., Johnson, S., Nurmahdi, H., Suckling, R.J., Hill, J., Korona, B., Weisshuhn, P.C., Sheppard, D., Meng, Y., Liang, S., Lowe, E.D., Lea, S.M., Redfield, C., Handford, P.A.(2024) Structure 32: 2325-2336.e5
- PubMed: 39488203
- DOI: https://doi.org/10.1016/j.str.2024.10.012
- Primary Citation of Related Structures:
9B3G, 9B3N - PubMed Abstract:
The Notch receptor is activated by the Delta/Serrate/Lag-2 (DSL) family of ligands. The organization of the extracellular signaling complex is unknown, although structures of Notch/ligand complexes comprising the ligand-binding region (LBR), and negative regulatory region (NRR) region, have been solved. Here, we investigate the human Notch-1 epidermal growth factor-like (EGF) 20-27 region, located between the LBR and NRR, and incorporating the Abruptex (Ax) region, associated with distinctive Drosophila phenotypes. Our analyses, using crystallography, NMR and small angle X-ray scattering (SAXS), support a rigid, elongated organization for EGF20-27 with the EGF20-21 linkage showing Ca 2+ -dependent flexibility. In functional assays, Notch-1 variants containing Ax substitutions result in reduced ligand-dependent trans-activation. When cis-JAG1 was expressed, Notch activity differences between WT and Ca 2+ -binding Ax variants were less marked than seen in the trans-activation assays alone, consistent with disruption of cis-inhibition. These data indicate the importance of Ca 2+ -stabilized structure and suggest the balance of cis- and trans-interactions explains the effects of Drosophila Ax mutations.
Organizational Affiliation:
Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK.
