NOTCH2 is activated by binding Delta-like and Jagged ligands (DLL/JAG) expressed in trans on neighboring cells (Shimizu et al. 1999, Shimizu et al. 2000, Hicks et al. 2000, Ji et al. 2004). In trans ligand-receptor binding is followed by ADAM10 mediated (Gibb et al. 2010, Shimizu et al. 2000) and gamma secretase complex mediated cleavage of NOTCH2 (Saxena et al. 2001, De Strooper et al. 1999), resulting in the release of the intracellular domain of NOTCH2, NICD2, into the cytosol. NICD2 traffics to the nucleus where it acts as a transcriptional regulator. For a recent review of the cannonical NOTCH signaling, please refer to Kopan and Ilagan 2009, D'Souza et al. 2010, Kovall and Blacklow 2010. CNTN1 (contactin 1), a protein involved in oligodendrocyte maturation (Hu et al. 2003) and MDK (midkine) (Huang et al. 2008, Gungor et al. 2011), which plays an important role in epithelial-to-mesenchymal transition, can also bind NOTCH2 and activate NOTCH2 signaling.
In the nucleus, NICD2 forms a complex with RBPJ (CBF1, CSL) and MAML (mastermind). The NICD2:RBPJ:MAML complex activates transcription from RBPJ binding promoter elements (RBEs) (Wu et al. 2000). NOTCH2 coactivator complexes directly stimulate transcription of HES1 and HES5 genes (Shimizu et al. 2002), both of which are known NOTCH1 targets. NOTCH2 but not NOTCH1 coactivator complexes, stimulate FCER2 transcription. Overexpression of FCER2 (CD23A) is a hallmark of B-cell chronic lymphocytic leukemia (B-CLL) and correlates with the malfunction of apoptosis, which is thought be an underlying mechanism of B-CLL development (Hubmann et al. 2002). NOTCH2 coactivator complexes together with CREBP1 and EP300 stimulate transcription of GZMB (granzyme B), which is important for the cytotoxic function of CD8+ T cells (Maekawa et al. 2008).
NOTCH2 gene expression is differentially regulated during human B-cell development, with NOTCH2 transcripts appearing at late developmental stages (Bertrand et al. 2000).
NOTCH2 mutations are a rare cause of Alagille syndrome (AGS). AGS is a dominant congenital multisystem disorder characterized mainly by hepatic bile duct abnormalities. Craniofacial, heart and kidney abnormalities are also frequently observed in the Alagille spectrum (Alagille et al. 1975). AGS is predominantly caused by mutations in JAG1, a NOTCH2 ligand (Oda et al. 1997, Li et al. 1997), but it can also be caused by mutations in NOTCH2 (McDaniell et al. 2006).
Hajdu-Cheney syndrome, an autosomal dominant disorder characterized by severe and progressive bone loss, is caused by NOTCH2 mutations that result in premature C-terminal NOTCH2 truncation, probably leading to increased NOTCH2 signaling (Simpson et al. 2011, Isidor et al. 2011, Majewski et al. 2011).
|Compartment||plasma membrane , cytosol , nucleoplasm|
|GO Biological Process||Notch signaling pathway (0007219)|
|10958687||Binding of Delta1, Jagged1, and Jagged2 to Notch2 rapidly induces cleavage, nuclear translocation, and hyperphosphorylation of Notch2||Mol Cell Biol||2000|
|10934472||Fringe differentially modulates Jagged1 and Delta1 signalling through Notch1 and Notch2||Nat Cell Biol||2000|
|10551863||Mouse jagged1 physically interacts with notch2 and other notch receptors. Assessment by quantitative methods||J Biol Chem||1999|
|15569487||Function of Delta4 gene and its effects on 32D cell differentiation||Chin Med J (Engl)||2004|
|20156974||ADAM10 is essential for Notch2-dependent marginal zone B cell development and CD23 cleavage in vivo||J Exp Med||2010|
|11518718||Murine notch homologs (N1-4) undergo presenilin-dependent proteolysis||J Biol Chem||2001|
|10206645||A presenilin-1-dependent gamma-secretase-like protease mediates release of Notch intracellular domain||Nature||1999|
|11187898||Notch-1 and Notch-2 exhibit unique patterns of expression in human B-lineage cells||Leukemia||2000|
|21632553||Notch signaling activated by replication stress-induced expression of midkine drives epithelial-mesenchymal transition and chemoresistance in pancreatic cancer||Cancer Res.||2011|
|14567914||F3/contactin acts as a functional ligand for Notch during oligodendrocyte maturation||Cell||2003|
|18469519||Midkine induces epithelial-mesenchymal transition through Notch2/Jak2-Stat3 signaling in human keratinocytes||Cell Cycle||2008|
|11986231||Notch2 is involved in the overexpression of CD23 in B-cell chronic lymphocytic leukemia||Blood||2002|
|18724371||Notch2 integrates signaling by the transcription factors RBP-J and CREB1 to promote T cell cytotoxicity||Nat. Immunol.||2008|
|16773578||NOTCH2 mutations cause Alagille syndrome, a heterogeneous disorder of the notch signaling pathway||Am J Hum Genet||2006|
|11866432||Functional diversity among Notch1, Notch2, and Notch3 receptors||Biochem Biophys Res Commun||2002|
|11101851||MAML1, a human homologue of Drosophila mastermind, is a transcriptional co-activator for NOTCH receptors||Nat Genet||2000|
|19379690||The canonical Notch signaling pathway: unfolding the activation mechanism||Cell||2009|
|20816393||Canonical and non-canonical Notch ligands||Curr Top Dev Biol||2010|
|20816392||Mechanistic insights into Notch receptor signaling from structural and biochemical studies||Curr. Top. Dev. Biol.||2010|
|803282||Hepatic ductular hypoplasia associated with characteristic facies, vertebral malformations, retarded physical, mental, and sexual development, and cardiac murmur||J. Pediatr.||1975|
|9207787||Mutations in the human Jagged1 gene are responsible for Alagille syndrome||Nat. Genet.||1997|
|9207788||Alagille syndrome is caused by mutations in human Jagged1, which encodes a ligand for Notch1||Nat. Genet.||1997|
|21378985||Mutations in NOTCH2 cause Hajdu-Cheney syndrome, a disorder of severe and progressive bone loss||Nat. Genet.||2011|
|21378989||Truncating mutations in the last exon of NOTCH2 cause a rare skeletal disorder with osteoporosis||Nat. Genet.||2011|
|21681853||Mutations in NOTCH2 in families with Hajdu-Cheney syndrome||Hum. Mutat.||2011|