Hierarchical Phosphorylation within the Ankyrin Repeat Domain Defines a Phosphoregulatory Loop That Regulates Notch Transcriptional Activity

Ranganathan, Prathibha; Carpió, Rodrigo Vásquez-Del; Kaplan, Fred M.; Wang, Hong; Gupta, Ashu; VanWye, Jeffrey; Capobianco, Anthony J.

doi:10.1074/jbc.m111.243600

Cited by 41 publications

(36 citation statements)

References 69 publications

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“…For instance, phosphorylation of serine 1901 and threonine 1898 were implicated in decreased formation of a Notch-Maml1-CSL ternary complex on DNA (33). To clarify the possible role of the specific serine residues in ICN/CSL interaction, we made ICN1 several construct with mutations in serine residues in RAM domain of ICN1.…”

Section: Resultsmentioning

confidence: 99%

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Effects of Notch Signaling on Regulation of Myeloid Cell Differentiation in Cancer

et al. 2014

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Functionally altered myeloid cells play an important role in immune suppression in cancer, in angiogenesis, and in tumor cells’ invasion and metastases. Here, we report that inhibition of Notch signaling in hematopoietic progenitor cells (HPC), myeloid-derived suppressor cells (MDSC), and dendritic cells (DC) is directly involved in abnormal myeloid cell differentiation in cancer. Inhibition of Notch signaling was caused by the disruption of the interaction between Notch receptor and transcriptional repressor CSL, which is normally required for efficient transcription of target genes. This disruption was the result of serine phosphorylation of Notch. We demonstrated that increased activity of caseine kinase 2 (CK2) observed in HPC and in MDSC could be responsible for the phosphorylation of Notch and down-regulation of Notch signaling. Inhibition of CK2 by siRNA or by pharmacological inhibitor restored Notch signaling in myeloid cells and substantially improved their differentiation, both in vitro and in vivo. This study demonstrates a novel mechanism regulation of Notch signaling in cancer. This may suggest a new perspective for pharmacological regulation of differentiation of myeloid cells in cancer.

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Section: Resultsmentioning

confidence: 99%

“…Serine/threonine caseine kinase 2 (CK2) previously was implicated in regulation of Notch activity under physiological conditions (33). We evaluated the presence of CK2 protein in Gr-1 + CD11b + myeloid cells and found that the amount of catalytic α domain of CK2 protein was similar between control and TB mice (Fig.…”

Section: Resultsmentioning

confidence: 99%

Effects of Notch Signaling on Regulation of Myeloid Cell Differentiation in Cancer

et al. 2014

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“…Granulocyte colony stimulating factor (Csf) has also been shown to phosphorylate Notch2-ICD leading to its inactivation [60]. Phosphorylation of Notch-ICD by Casein kinase 2 (CK2) at threonine 1898 and serine 1901 also results in decreased binding of the Notch-Mastermind-CSL ternary complex to DNA and subsequently lower transcriptional activity [61]. Cyclin C/cyclin-dependent kinase (CDK) 8 dependent phosphorylation of Notch ICD is important for its activity and turnover [62].…”

Section: Discussionmentioning

confidence: 99%

Kinase active Misshapen regulates Notch signaling in Drosophila melanogaster

Mishra

Sachan

Mutsuddi

et al. 2015

Experimental Cell Research

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“…Interestingly, Notch signaling and CK2 are reported to be involved in regulating stabilization of phosphatase and tensin homolog (PTEN), an inhibitor of Akt activation (Silva et al, 2010). Furthermore, recent evidence suggests that intracellular domain of Notch is a novel target of phosphorylation by CK2 (Ranganathan et al, 2011). The phosphorylation of intracellular domain of Notch decreases the transcriptional activities of Notch/CSL complex, suggesting that CK2 negatively regulates canonical Notch signaling.…”

Section: Discussionmentioning

confidence: 99%

Notch signaling regulates the phosphorylation of Akt and survival of lipopolysaccharide-activated macrophages via regulator of G protein signaling 19 (RGS19)

2014

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Macrophages play critical roles in innate immune defense by sensing microbes using pattern-recognition receptors. Lipopolysaccharide (LPS) stimulates macrophages via TLR, which leads to activation of downstream signaling cascades. In this study, we investigated the roles of a conserved signaling pathway, Notch signaling, in regulating the downstream signaling cascades of the LPS/TLR4 pathways in macrophages. Using a phosphoproteomic approach and a gamma-secretase inhibitor (GSI) to suppress the processing and activation of Notch signaling, we identified regulator of G protein signaling 19 (RGS19) as a target protein whose phosphorylation was affected by GSI treatment. RGS19 is a guanosine triphosphatase (GTPase)-activating protein that functions to negatively regulate G protein-coupled receptors via Gαi/Gαq-linked signaling. Stimulation of RAW264.7 cells with LPS increased the level of the phosphorylated form of RGS19, while LPS stimulation in the presence of GSI decreased its level. GSI treatment did not alter the mRNA level of rgs19. Treatment with GSI or silencing of rgs19 in macrophages impaired the phosphorylation of Akt Thr308 upon LPS stimulation. Furthermore, targeted deletion of a DNA-binding protein and binding partner of the Notch receptor, RBP-Jκ/CSL, in macrophages resulted in delayed and decreased Akt phosphorylation. Because the PI3K/Akt pathway regulates cell survival in various cell types, the cell cycle and cell death were assayed upon GSI treatment, phosphatidylinositol 3 kinase (PI3K) inhibitor treatment or silencing of rgs19. GSI treatment resulted in decreased cell populations in the G1 and S phases, while it increased the cell population of cell death. Similarly, silencing of rgs19 resulted in a decreased cell population in the G1 phase and an increased cell population in the subG1 phase. Inhibition of Akt phosphorylation by PI3K inhibitor in LPS-stimulated macrophages increased cell population in G1 phase, suggesting a possible cell cycle arrest. Taken together, these results indicate that Notch signaling positively regulates phosphorylation of Akt, possibly via phosphorylation of RGS19, and inhibition of both molecules affects the cell survival and cell cycle of macrophages upon LPS stimulation.

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Hierarchical Phosphorylation within the Ankyrin Repeat Domain Defines a Phosphoregulatory Loop That Regulates Notch Transcriptional Activity

Cited by 41 publications

References 69 publications

Effects of Notch Signaling on Regulation of Myeloid Cell Differentiation in Cancer

Effects of Notch Signaling on Regulation of Myeloid Cell Differentiation in Cancer

Kinase active Misshapen regulates Notch signaling in Drosophila melanogaster

Notch signaling regulates the phosphorylation of Akt and survival of lipopolysaccharide-activated macrophages via regulator of G protein signaling 19 (RGS19)

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