Project description:Protein deamidation is emerging as a post-translational modification that regulates protein function. The general role of protein deamidation is emerging asn fundamental to biological processes, yet remains is poorly understood. Here, we report that the rate-limiting enzyme of pyrimidine synthesis, a trifunctional enzyme containing activity of carbamoyl phosphate synthetase, aspartyl transcarbamoylase and dihydroorotase (CAD), deamidates the RelA subunit to inactivate NF-κB and promote glycolysis. Functional screening and identified CAD as a negative regulator of NF-κB activation, and biochemical analysis demonstrated that CAD deamidatesd RelA in vitro and in cellsto negate NF-κB activation. D eamidated RelA, though failed to activate the expression of NF-κB-dependent genes, thoughbut it up-regulated that of key glycolytic enzymes to promote glycolysis and cell proliferation. In proliferating cells, CAD is activated and catalyzes de novo pyrimidine synthesis to meet the metabolic need during S phase. CAD-mediated RelA deamidation and NF-κB inactivation and glycolytic gene expression paralleled in a cell cycle-dependent mannerdriven by CAD-mediated RelA deamidation are necessary for cell proliferation. In addition, CAD promoted glycolysis via deamidated RelA that up-regulated the expression of key glycolytic enzymes. Stratification of cancer cell lines by CAD-mediated RelA deamidation predicted their sensitivity to inhibitors of glycolytic enzymes, while a subset of mutations predisposed RelA to deamidation and promoted glycolysis to enable cell proliferation. This work describes a process of metabolic reprogramming enabled by CAD-mediated RelA deamidation that underpins cell proliferation and tumorigenesis.
Project description:A structure-function study of NF-kB subunit RelA and coactivator CBP/p300 interaction reveals the critical role of CBP/p300 in recruitment of RelA to its target promoter site. mRNA profiles of unstimulated or stimulated with TNFa rela-/- MEF reconstituted with RelA wild type or mutants were generated by deep sequencing, in duplicate
Project description:MEF proficient or deficient in PKBalpha, or PKBalpha knockout MEF where PKBalpha expression was reconstituted by stable transfection were subjected to 10Gy gamma-IR treatment. 4 or 24 hours after treatment, gene expression changes were analyzed. Keywords: genotype0-specific stress response in PKBalpha MEF
Project description:Protein deamidation is emerging as a post-translational modification that regulates protein function. The general role of protein deamidation is emerging asn fundamental to biological processes, yet remains is poorly understood. Here, we report that the rate-limiting enzyme of pyrimidine synthesis, a trifunctional enzyme containing activity of carbamoyl phosphate synthetase, aspartyl transcarbamoylase and dihydroorotase (CAD), deamidates the RelA subunit to inactivate NF-κB and promote glycolysis. Functional screening and identified CAD as a negative regulator of NF-κB activation, and biochemical analysis demonstrated that CAD deamidatesd RelA in vitro and in cellsto negate NF-κB activation. D eamidated RelA, though failed to activate the expression of NF-κB-dependent genes, thoughbut it up-regulated that of key glycolytic enzymes to promote glycolysis and cell proliferation. In proliferating cells, CAD is activated and catalyzes de novo pyrimidine synthesis to meet the metabolic need during S phase. CAD-mediated RelA deamidation and NF-κB inactivation and glycolytic gene expression paralleled in a cell cycle-dependent mannerdriven by CAD-mediated RelA deamidation are necessary for cell proliferation. In addition, CAD promoted glycolysis via deamidated RelA that up-regulated the expression of key glycolytic enzymes. Stratification of cancer cell lines by CAD-mediated RelA deamidation predicted their sensitivity to inhibitors of glycolytic enzymes, while a subset of mutations predisposed RelA to deamidation and promoted glycolysis to enable cell proliferation. This work describes a process of metabolic reprogramming enabled by CAD-mediated RelA deamidation that underpins cell proliferation and tumorigenesis.
Project description:NFkB RelA is the potent transcriptional activator of inflammatory response genes. We stringently defined a list of direct RelA target genes by integrating physical (ChIPseq) and functional (RNAseq in knockouts) datasets. We then dissected each gene's regulatory strategy by testing RelA variants in a novel primary-cell genetic complementation assay. All endogenous target genes required that RelA makes DNA-base-specific contacts, and none could be activated by the DNA binding domain alone. However, endogenous target genes differed widely in how they employ the two transactivation domains. Through model-aided analysis of the dynamic timecourse data we reveal gene-specific synergy and redundancy of TA1 and TA2. Given that post-translational modifications control TA1 activity and intrinsic affinity for coactivators determines TA2 activity, the differential TA logics suggests context-dependent vs. context-independent control of endogenous RelA-target genes. While some inflammatory initiators appear to require co-stimulatory TA1 activation, inflammatory resolvers are a part of the NFkB RelA core response.
Project description:Immuno-histochemistry for RelA in breast tumors revealed a range of staining intensity and negative correlation between RelA levels and proliferation-index in estrogen receptor-positive tumors. Conditional expression of RelA arrested proliferation in primary mammary and fallopian tube epithelial cells. RelA dependent CDK4 downregulation was responsible for activating the G1/S checkpoint and cell cycle arrest. RelA target genes, including Interferon Response Factors (IRF), were up-regulated in the arrested cells. Among the IRFs, IRF1 expression correlates with RelA expression. Suppressing IRF1 restored CDK4 levels and rescued RelA-dependent proliferation arrest analogous to abrogating the G1/S checkpoint or restoring CDK4 levels. Apart from cyclins, regulation of CDK4 by the RelA-IRF1 transcriptional network controls proliferation of breast tumors and predicts sensitivity to a CDK4/6 inhibitor.
Project description:Background: Lymphotoxin signaling via the lymphotoxin-β receptor (LTβR) has been implicated in several biological processes, ranging from development of secondary lymphoid organs, maintenance of splenic tissue, host defense against pathogens, autoimmunity, and lipid homeostasis. The major transcription factor that is activated by LTβR crosslinking is NF-κB. Two signaling pathways have been described that result in the activation of classical p50-RelA and alternative p52-RelB NF-κB heterodimers. Results: Using microarray analysis, we investigated the transcriptional response downstream of the LTβR in mouse embryoni fibroblasts (MEF) and its regulation by the RelA and RelB subunits of NF-κB. We describe novel LTβR-responsive genes that are regulated by RelA and/or RelB. Interestingly, we found that the majority of LTβR-regulated genes require the presence of both RelA and RelB, suggesting significant crosstalk between the two NF-κB activation pathways. Gene Ontology (GO) analysis confirmed that LTβR-NF-κB target genes are predominantly involved in the regulation of immune responses. However, other biological processes, such as apoptosis/cell death, cell cycle, angiogenesis, and taxis were also regulated by LTβR signaling. Moreover, we show that activation of the LTβR inhibits the expression of a key adipogenic transcription factor, peroxisome proliferator activated receptor-γ (pparg), suggesting that LTβR signaling may interfere with adipogenic differentiation. Conclusions: Thus, microarray analysis of LTβR-stimulated fibroblasts revealed further insight into the transcriptional response of LTβR signaling and its regulation by the NF-κB family members RelA and RelB. Keywords: cell type comparison (wt vs relA-/- vs relB-/-) after genetic modification using a time course for each cell type (wt, relA-/-, relB-/-) two time points were analysed (0h as control and 10h) using 3 technical replicates resulting in 18 samples in total
Project description:A structure-function study of NF-kB subunit RelA and coactivator CBP/p300 interaction reveals the critical role of CBP/p300 in recruitment of RelA to its target promoter site.