Notch1 transcriptional ternary complex (Notch1-CSL-MAML complex)

The Notch1 transcriptional ternary complex is the nuclear effector of the Notch signaling pathway, composed of the Notch1 intracellular domain (NICD1), the DNA-binding protein CSL (also known as RBPJ), and a member of the Mastermind-like (MAML) family of co-activators. Upon ligand binding at the cell surface, Notch1 undergoes proteolytic cleavage to release NICD1, which translocates to the nucleus to assemble this complex on specific DNA promoter sequences. This assembly displaces co-repressors and recruits additional transcriptional machinery to drive the expression of genes critical for cell growth and survival, such as MYC and HES1. In many cancers, particularly T-cell acute lymphoblastic leukemia (T-ALL) and various solid tumors, the pathway is constitutively active due to mutations that stabilize NICD1 or promote complex formation. Therapeutic strategies targeting this complex aim to disrupt the protein-protein interactions (PPI) between its components, offering a more direct approach than upstream gamma-secretase inhibitors which often suffer from severe gastrointestinal side effects. Small molecules like CB-103 have been developed to specifically inhibit this nuclear assembly, providing a potential precision medicine approach for Notch-driven malignancies.

Other names

Notch1-RBPJ-MAML complexNotch1 intracellular domain transcriptional complexNICD1-CSL-MAML1 complexNotch1 core transcriptional complex

Inhibition of the protein-protein interaction between the Notch intracellular domain (NICD), the DNA-binding protein CSL (RBPJ), and the co-activator Mastermind-like (MAML), thereby preventing the assembly of the active transcriptional complex and blocking the expression of Notch target genes such as HES1 and MYC.