NMR Structure of a Prototype LNR Module from Human Notch1
[NOTC1_HUMAN] Defects in NOTCH1 are a cause of aortic valve disease 1 (AOVD1) [MIM:109730]. A common defect in the aortic valve in which two rather than three leaflets are present. It is often associated with aortic valve calcification and insufficiency. In extreme cases, the blood flow may be so restricted that the left ventricle fails to grow, resulting in hypoplastic left heart syndrome.
[NOTC1_HUMAN] Functions as a receptor for membrane-bound ligands Jagged1, Jagged2 and Delta1 to regulate cell-fate determination. Upon ligand activation through the released notch intracellular domain (NICD) it forms a transcriptional activator complex with RBPJ/RBPSUH and activates genes of the enhancer of split locus. Affects the implementation of differentiation, proliferation and apoptotic programs. May be important for normal lymphocyte function. In altered form, may contribute to transformation or progression in some T-cell neoplasms. Involved in the maturation of both CD4+ and CD8+ cells in the thymus. May be important for follicular differentiation and possibly cell fate selection within the follicle. During cerebellar development, may function as a receptor for neuronal DNER and may be involved in the differentiation of Bergmann glia. Represses neuronal and myogenic differentiation. May enhance HIF1A function by sequestering HIF1AN away from HIF1A (By similarity).
Publication Abstract from PubMed
Notch1 is a member of a conserved family of large modular heterodimeric type 1 transmembrane receptors that control differentiation in multicellular animals. Receptor maturation is accompanied by a furin-dependent cleavage that converts the Notch1 precursor polypeptide into a heterodimer consisting of an extracellular ligand-binding subunit (NEC) and a transmembrane signaling subunit (NTM). Binding of a physiologic ligand to NEC induces signaling by triggering additional proteolytic cleavages in NTM, which allow its intracellular region to translocate to the nucleus where it participates in a transcriptional activation complex. In the absence of ligand, the three conserved LNR modules of the NEC subunit participate in maintaining the receptor in its resting conformation. Here, we report the solution structure of the first LNR module (LNR_A) of human Notch1, and identify residues of LNR_A perturbed by the presence of the adjacent module LNR_B. LNR_A is held together by a unique arrangement of three disulfide bonds and a single bound Ca(2+) ion, and adopts a novel fold that falls in the general class of irregular disulfide-bonded structures. Residues perturbed by the presence of the adjacent LNR_B module are predominantly hydrophobic, and lie on one face of the module. These studies represent an initial step toward understanding the structural interrelationships among the three contiguous LNR modules required for proper regulation of Notch signaling.
Nuclear magnetic resonance structure of a prototype Lin12-Notch repeat module from human Notch1.,Vardar D, North CL, Sanchez-Irizarry C, Aster JC, Blacklow SC Biochemistry. 2003 Jun 17;42(23):7061-7. PMID:12795601
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.