Insights into Autoregulation of Notch3 from Structural and Functional Studies of Its Negative Regulatory Region.
Publication Type:Journal Article
Source:Structure, Volume 23, Issue 7, p.1227-35 (2015)
Keywords:Cell Line, Tumor, Crystallography, X-Ray, HEK293 Cells, Humans, Models, Molecular, Mutation, Missense, Protein Binding, Protein Interaction Domains and Motifs, Protein Multimerization, Proteolysis, Receptor, Notch3, Receptors, Notch
<p>Notch receptors are transmembrane proteins that undergo activating proteolysis in response to ligand stimulation. A negative regulatory region (NRR) maintains receptor quiescence by preventing protease cleavage prior to ligand binding. We report here the X-ray structure of the NRR of autoinhibited human Notch3, and compare it with the Notch1 and Notch2 NRRs. The overall architecture of the autoinhibited conformation, in which three LIN12-Notch repeat (LNR) modules wrap around a heterodimerization domain, is preserved in Notch3, but the autoinhibited conformation of the Notch3 NRR is less stable. The Notch3 NRR uses a highly conserved surface on the third LNR module to form a dimer in the crystal. Similar homotypic interfaces exist in Notch1 and Notch2. Together, these studies reveal distinguishing structural features associated with increased basal activity of Notch3, demonstrate increased ligand-independent signaling for disease-associated mutations that map to the Notch3 NRR, and identify a conserved dimerization interface present in multiple Notch receptors.</p>