Mib-Jag1-Notch signalling regulates patterning and structural roles of the notochord by controlling cell-fate decisions

The Notch pathway functions in multiple cell fate determination processes in invertebrate embryos, including the decision between the neuroblast and epidermoblast lineages in Drosophila. In the mouse, targeted mutation of the Notch pathway genes Notch1 and RBP-Jk has demonstrated a role for these genes in somite segmentation, but a function in neurogenesis and in cell fate decisions has not been shown. Here we show that these mutations lead to altered expression of the Notch signalling pathway homologues Hes-5, Mash-1 and Dll1, resulting in enhanced neurogenesis. Precocious neuronal differentiation is indicated by the expanded expression domains of Math4A, neuroD and NSCL-1. The RBP-Jk mutation has stronger effects on expression of these genes than does the Notch1 mutation, consistent with functional redundancy of Notch genes in neurogenesis. Our results demonstrate conservation of the Notch pathway and its regulatory mechanisms from fly to mouse, and support a role for the murine Notch signalling pathway in the regulation of neural stem cell differentiation.

Download Full-text

Dynamics of Notch signalling in the mouse oviduct and uterus during the oestrous cycle

Reproduction Fertility and Development ◽

10.1071/rd15029 ◽

2016 ◽

Vol 28 (11) ◽

pp. 1663 ◽

Cited By ~ 5

Author(s):

D. Murta ◽

M. Batista ◽

A. Trindade ◽

E. Silva ◽

L. Mateus ◽

...

Keyword(s):

Real Time ◽

Cell Fate ◽

Expression Patterns ◽

Cell Signalling ◽

Notch Signalling ◽

Notch Receptor ◽

Effector Proteins ◽

Oestrous Cycle ◽

Cell Fate Decisions ◽

Effector Genes

The oviduct and uterus undergo extensive cellular remodelling during the oestrous cycle, requiring finely tuned intercellular communication. Notch is an evolutionarily conserved cell signalling pathway implicated in cell fate decisions in several tissues. In the present study we evaluated the quantitative real-time polymerase chain reaction (real-time qPCR) and expression (immunohistochemistry) patterns of Notch components (Notch1–4, Delta-like 1 (Dll1), Delta-like 4 (Dll4), Jagged1–2) and effector (hairy/enhancer of split (Hes) 1–2, Hes5 and Notch-Regulated Ankyrin Repeat-Containing Protein (Nrarp)) genes in the mouse oviduct and uterus throughout the oestrous cycle. Notch genes are differentially transcribed and expressed in the mouse oviduct and uterus throughout the oestrous cycle. The correlated transcription levels of Notch components and effector genes, and the nuclear detection of Notch effector proteins, indicate that Notch signalling is active. The correlation between transcription levels of Notch genes and progesterone concentrations, and the association between expression of Notch proteins and progesterone receptor (PR) activation, indicate direct progesterone regulation of Notch signalling. The expression patterns of Notch proteins are spatially and temporally specific, resulting in unique expression combinations of Notch receptor, ligand and effector genes in the oviduct luminal epithelium, uterus luminal and glandular epithelia and uterine stroma throughout the oestrous cycle. Together, the results of the present study imply a regulatory role for Notch signalling in oviduct and uterine cellular remodelling occurring throughout the oestrous cycle.

Download Full-text

SUMOylated Non-canonical Polycomb PRC1.6 Complex as a Prerequisite for Recruitment of Transcription Factor RBPJ

10.21203/rs.3.rs-380941/v1 ◽

2021 ◽

Author(s):

Małgorzata Sotomska ◽

Robert Liefke ◽

Francesca Ferrante ◽

Heiko Schwederski ◽

Franz Oswald ◽

...

Keyword(s):

Gene Expression ◽

Transcription Factor ◽

Cell Fate ◽

Target Gene ◽

Target Genes ◽

Adult Stem Cell ◽

Notch Signalling ◽

Cell Fate Decisions ◽

Contact Points ◽

Coactivator Complex

Abstract BackgroundNotch signaling controls cell fate decisions in many contexts during development and adult stem cell homeostasis and, when dysregulated, leads to carcinogenesis. The central transcription factor RBPJ assembles the Notch coactivator complex in the presence of Notch signalling, and represses Notch target gene expression in its absence.ResultsWe identified L3MBTL2 and additional members of the non-canonical polycomb repressive PRC1.6 complex in DNA-bound RBPJ associated complexes and demonstrate that L3MBTL2 directly interacts with RBPJ. Depletion of RBPJ does not affect occupancy of PRC1.6 components at Notch target genes. Conversely, absence of L3MBTL2 reduces RBPJ occupancy at enhancers of Notch target genes. Since L3MBTL2 and additional members of the PRC1.6 are known to be SUMOylated, we investigated whether RBPJ uses SUMO-moieties as contact points. Indeed, we found that RBPJ binds to SUMO2/3 and that this interaction depends on a defined SUMO-interaction motif. Furthermore, we show that pharmacological inhibition of SUMOylation reduces RBPJ occupancy at Notch target genes.ConclusionsWe propose that the PRC1.6 complex and its conjugated SUMO-modifications provide a scaffold that is recognized by RBPJ and promotes its recruitment to Notch target genes.

Download Full-text

Phosphatidic acid increases Notch signalling by affecting Sanpodo trafficking during Drosophila sensory organ development

Scientific Reports ◽

10.1038/s41598-020-78831-z ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Ignacio Medina-Yáñez ◽

Gonzalo H. Olivares ◽

Franco Vega-Macaya ◽

Marek Mlodzik ◽

Patricio Olguín

Keyword(s):

Phosphatidic Acid ◽

Cell Fate ◽

Phospholipase D ◽

Membrane Lipids ◽

Adaptor Protein ◽

Notch Signalling ◽

Α Subunit ◽

Asymmetric Cell Divisions ◽

Cell Fate Decisions ◽

Cell Divisions

AbstractOrgan cell diversity depends on binary cell-fate decisions mediated by the Notch signalling pathway during development and tissue homeostasis. A clear example is the series of binary cell-fate decisions that take place during asymmetric cell divisions that give rise to the sensory organs of Drosophila melanogaster. The regulated trafficking of Sanpodo, a transmembrane protein that potentiates receptor activity, plays a pivotal role in this process. Membrane lipids can regulate many signalling pathways by affecting receptor and ligand trafficking. It remains unknown, however, whether phosphatidic acid regulates Notch-mediated binary cell-fate decisions during asymmetric cell divisions, and what are the cellular mechanisms involved. Here we show that increased phosphatidic acid derived from Phospholipase D leads to defects in binary cell-fate decisions that are compatible with ectopic Notch activation in precursor cells, where it is normally inactive. Null mutants of numb or the α-subunit of Adaptor Protein complex-2 enhance dominantly this phenotype while removing a copy of Notch or sanpodo suppresses it. In vivo analyses show that Sanpodo localization decreases at acidic compartments, associated with increased internalization of Notch. We propose that Phospholipase D-derived phosphatidic acid promotes ectopic Notch signalling by increasing receptor endocytosis and inhibiting Sanpodo trafficking towards acidic endosomes.

Download Full-text

Non-degradative ubiquitination of the Notch1 receptor by the E3 ligase MDM2 activates the Notch signalling pathway

Biochemical Journal ◽

10.1042/bj20121249 ◽

2013 ◽

Vol 450 (3) ◽

pp. 523-536 ◽

Cited By ~ 31

Author(s):

Susanne Pettersson ◽

Matylda Sczaniecka ◽

Lorna McLaren ◽

Fiona Russell ◽

Karen Gladstone ◽

...

Keyword(s):

Cell Fate ◽

E3 Ligase ◽

Notch Signalling ◽

Notch Receptor ◽

Signalling Pathway ◽

Notch 1 ◽

Notch Signalling Pathway ◽

Cell Fate Decisions ◽

Site Binding ◽

Notch1 Receptor

The Notch receptor is necessary for modulating cell fate decisions throughout development, and aberrant activation of Notch signalling has been associated with many diseases, including tumorigenesis. The E3 ligase MDM2 (murine double minute 2) plays a role in regulating the Notch signalling pathway through its interaction with NUMB. In the present study we report that MDM2 can also exert its oncogenic effects on the Notch signalling pathway by directly interacting with the Notch 1 receptor through dual-site binding. This involves both the N-terminal and acidic domains of MDM2 and the RAM [RBP-Jκ (recombination signal-binding protein 1 for Jκ)-associated molecule] and ANK (ankyrin) domains of Notch 1. Although the interaction between Notch1 and MDM2 results in ubiquitination of Notch1, this does not result in degradation of Notch1, but instead leads to activation of the intracellular domain of Notch1. Furthermore, MDM2 can synergize with Notch1 to inhibit apoptosis and promote proliferation. This highlights yet another target for MDM2-mediated ubiquitination that results in activation of the protein rather than degradation and makes MDM2 an attractive target for drug discovery for both the p53 and Notch signalling pathways.

Download Full-text

CSL-independent Notch signalling: a checkpoint in cell fate decisions during development?

Current Opinion in Genetics & Development ◽

10.1016/s0959-437x(02)00336-2 ◽

2002 ◽

Vol 12 (5) ◽

pp. 524-533 ◽

Cited By ~ 156

Author(s):

A Arias

Keyword(s):

Cell Fate ◽

Notch Signalling ◽

Cell Fate Decisions

Download Full-text

The effects of conformational heterogeneity on the binding of the Notch intracellular domain to effector proteins: a case of biologically tuned disorder

Biochemical Society Transactions ◽

10.1042/bst0360157 ◽

2008 ◽

Vol 36 (2) ◽

pp. 157-166 ◽

Cited By ~ 32

Author(s):

Angela Bertagna ◽

Dima Toptygin ◽

Ludwig Brand ◽

Doug Barrick

Keyword(s):

Cell Fate ◽

Tertiary Structure ◽

Transmembrane Protein ◽

Notch Signalling ◽

Chain Model ◽

Intracellular Domain ◽

Cell Fate Decisions ◽

Notch Intracellular Domain ◽

Binding Regions ◽

The Impact

Cell-fate decisions in metazoans are frequently guided by the Notch signalling pathway. Notch signalling is orchestrated by a type-1 transmembrane protein, which, upon interacting with extracellular ligands, is proteolytically cleaved to liberate a large intracellular domain [NICD (Notch intracellular domain)]. NICD enters the nucleus where it binds the transcription factor CSL (CBF1/suppressor of Hairless/Lag-1) and activates transcription of Notch-responsive genes. In the present paper, the interaction between the Drosophila NICD and CSL will be examined. This interaction involves two separate binding regions on NICD: the N-terminal tip of NICD {the RAM [RBP-Jκ (recombination signal-binding protein 1 for Jκ)-associated molecule] region} and an ankyrin domain ∼100 residues away. CD studies show that the RAM region of NICD lacks α-helical and β-sheet secondary structure, and also lacks rigid tertiary structure. Fluorescence studies show that the tryptophan residues in RAM are highly solvated and are quenched by solvent. To assess the impact of this apparent disorder on the bivalent binding of NICD to CSL, we modelled the region between the RAM and ANK (ankyrin repeat)-binding regions using polymer statistics. A WLC (wormlike chain) model shows that the most probable sequence separation between the two binding regions is ∼50 Å (1 Å=0.1 nm), matching the separation between these two sites in the complex. The WLC model predicts a substantial enhancement of ANK occupancy via effective concentration, and suggests that the linker length between the two binding regions is optimal for bivalent interaction.

Download Full-text

HER2 stabilizes survivin while concomitantly down-regulating survivin gene transcription by suppressing Notch cleavage

Biochemical Journal ◽

10.1042/bj20121716 ◽

2013 ◽

Vol 451 (1) ◽

pp. 123-134 ◽

Cited By ~ 16

Author(s):

Ji-hyun Ju ◽

Wonseok Yang ◽

Sunhwa Oh ◽

KeeSoo Nam ◽

Kyung-min Lee ◽

...

Keyword(s):

Breast Cancer ◽

Cell Fate ◽

Target Genes ◽

Growth Factor Receptor ◽

Cyclin B1 ◽

Notch Signalling ◽

Her2 Overexpression ◽

Cell Fate Decisions ◽

Notch Intracellular Domain ◽

Notch Cleavage

In breast cancer, the HER2 (human epidermal growth factor receptor 2) receptor tyrosine kinase is associated with extremely poor prognosis and survival. Notch signalling has a key role in cell-fate decisions, especially in cancer-initiating cells. The Notch intracellular domain produced by Notch cleavage is translocated to the nucleus where it activates transcription of target genes. To determine the combinatory effect of HER2 and Notch signalling in breast cancer, we investigated the effect of HER2 on Notch-induced cellular phenomena. We found the down-regulation of Notch-dependent transcriptional activity by HER2 overexpression. Also, the HER2/ERK (extracellular-signal-regulated kinase) signal pathway down-regulated the activity of γ-secretase. When we examined the protein level of Notch target genes in HER2-overexpressing cells, we observed that the level of survivin, downstream of Notch, increased in HER2 cells. We found that activation of ERK resulted in a decrease in XAF1 [XIAP (X-linked inhibitor of apoptosis)-associated factor 1] which reduced the formation of the XIAP–XAF1 E3 ligase complex to ubiquitinate survivin. In addition, Thr34 of survivin was shown to be the most important residue in determining survivin stability upon phosphorylation after HER2/Akt/CDK1 (cyclin-dependent kinase 1)–cyclin B1 signalling. The results of the present study show the combinatorial effects of HER2 and Notch during breast oncogenesis.

Download Full-text