Notch 1 receptor (NOTCH1)

The Notch 1 receptor is a type I transmembrane protein that functions as a ligand-activated transcription factor, critical for cell-fate decisions and tissue homeostasis (UniProt P46531). Its activation is tightly controlled by the negative regulatory region (NRR), which consists of three Lin-12/Notch repeats and a heterodimerization domain that autoinhibits the receptor by shielding the S2 proteolytic site (Gordon et al., 2007). Ligand binding (e.g., Delta-like 4) induces a conformational change in the NRR, exposing the S2 site to ADAM proteases, which is followed by S3 cleavage within the transmembrane core by the gamma-secretase complex (Science, 2009). This sequential proteolysis releases the Notch intracellular domain (NICD), which translocates to the nucleus to activate target genes such as HES1 and MYC (Nature, 2004). Mutations in the NRR that destabilize the autoinhibitory conformation are a primary driver of T-cell acute lymphoblastic leukemia (T-ALL) (Weng et al., 2004). Therapeutic development has focused on monoclonal antibodies, such as Brontictuzumab, which bind the NRR to stabilize the inactive state, as well as gamma-secretase inhibitors that block the transmembrane core cleavage (ClinicalTrials.gov: NCT01778439).

Other names

Notch negative regulatory regionNRRNotch transmembrane coreNotch heterodimerization domainNotch negative regulatory region and transmembrane corehN1

Stabilization of the negative regulatory region (NRR) to prevent S2 cleavage by ADAM proteases and inhibition of gamma-secretase mediated S3 cleavage within the transmembrane core.