Neurogenic locus Notch 1 (IPR022362)
Short name: Notch_1
Overlapping homologous superfamilies
- Notch (IPR008297)
- Neurogenic locus Notch 1 (IPR022362)
Notch cell surface receptors are large, single-pass type-1 transmembrane proteins found in a diverse range of metazoan species, from human to Caenorhabditis species. The fruit fly, Drosophila melanogaster, possesses only one Notch protein, whereas in C.elegans, two receptors have been found; by contrast, four Notch paralogues (designated N1-4) have been identified in mammals, playing both unique and redundant roles.
The hetero-oligomer Notch comprises a large extracellular domain (ECD), containing 10-36 tandem Epidermal Growth Factor (EFG)-like repeats, which are involved in ligand interactions; a negative regulatory region, including three cysteine-rich Lin12-Notch Repeats (LNR); a single trans-membrane domain (TM); a small intracellular domain (ICD), which includes a RAM (RBPjk-association module) domain; six ankyrin repeats (ANK), which are involved in protein-protein interactions; and a PEST domain. Drosophila Notch also contains an OPA domain [PMID: 19379690].
Notch signalling is an evolutionarily conserved pathway involved in a wide variety of developmental processes, including adult homeostasis and stem cell maintenance, cell proliferation and apoptosis [PMID: 10221902]. Notch is activated by a range of ligands -the so-called DSL ligands (Delta/Seratte/LAG-2). Activation is also mediated by a sequence of proteolytic events: ligand binding leads to cleavage of Notch by ADAM proteases [PMID: 12354787] at site 2 (S2) and presenilin-1/g-secretase at sites 3 (S3)and 4 (S4) [PMID: 10206645].The last cleavage releases the Notch intracellular part of the protein (NICD) from the membrane and, upon release, the NICD translocates to the nucleus where it associates with a CBF1/RBJk/Su(H)/Lag1 (CSL) family of DNA-binding proteins. The subsequent recruitment of a co-activator mastermind like (MAML1) protein [PMID: 11101851] promotes transcriptional activation of Notch target genes: well established Notch targets are the Hes and Hey gene families.
Aberrant Notch function and signalling has been associated with a number of human disorders, including Allagile syndrome, spondylocostal dysostosis, aortic valve disease, CADASIL (Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy), and T-cell Acute Lympho-blastic Leukemia (T-ALL); it has also been implicated in various human carcinomas [PMID: 12668592, PMID: 16429119].
Notch 1 has a widespread pattern of expression and has been demonstrated to be involved in several processes such as mesenchymal cell differentiation, spermatogenesis, and osteoblastic cell differentiation. The pattern of expression of Notch 1 in adult human tissues reveals that this receptor may play multiple roles in several cell types, including neurons, lymphoid cells and skeletal muscle cells, as well as suprabasal cells in stratified epithelia [PMID: 15145534].
- PR01984 (NOTCH1)