Project description:Cancer is a disease of aberrant intracellular signaling. The NF-κB family of transcription factors and the Ras family of small GTPases have emerged as particularly important mediators of the pro-proliferative signaling that drives tumorigenesis and carcinogenesis. The κB-Ras proteins, encoded by the genes Nkiras1 and Nkiras2, were previously shown to inhibit both NF-κB and Ras pathway activation through independent molecular mechanisms, implicating them as tumor suppressors with potentially broad relevance to human cancers. In mice, each κB-Ras protein can compensate fully for loss of the other, making the functionally redundant in the context of Ras signaling. To understand the global effects of full κB-Ras deficiency in the context of Ras activation, we use microarray analysis to compare the transcriptome of MEFs lacking only κB-Ras 1 (Nkiras1-/- Nkiras2+/+, 1SKO) and MEFs lacking both isoforms of κB-Ras (Nkiras1-/- Nkiras2-/-, DKO) with and without EGF stimulation.
Project description:To understand how integration of multiple data types can help decipher cellular responses at the systems level, we analyzed the mitogenic response of human mammary epithelial cells to epidermal growth factor (EGF) using whole genome microarrays, mass spectrometry-based proteomics and large-scale western blots with over 1000 antibodies. A time course analysis revealed significant differences in the expression of 3172 genes and 596 proteins, including protein phosphorylation changes measured by western blot. Integration of these disparate data types showed that each contributed qualitatively different components to the observed cell response to EGF and that varying degrees of concordance in gene expression and protein abundance measurements could be linked to specific biological processes. Networks inferred from individual data types were relatively limited, whereas networks derived from the integrated data recapitulated the known major cellular responses to EGF and exhibited more highly connected signaling nodes than networks derived from any individual dataset. While cell cycle regulatory pathways were altered as anticipated, we found the most robust response to mitogenic concentrations of EGF was induction of matrix metalloprotease cascades, highlighting the importance of the EGFR system as a regulator of the extracellular environment. These results demonstrate the value of integrating multiple levels of biological information to more accurately reconstruct networks of cellular response. Keywords: time-course analysis
Project description:Hexokinase 2 (Hxk2) of Saccharomyces cerevisiae is a dual function hexokinase, acting as a glycolytic enzyme and being involved in the transcriptional regulation of glucose-repressible genes. Relief from glucose repression is accompanied by phosphorylation of Hxk2 at serine 15, which has been attributed to the protein kinase Tda1. To explore the role of Tda1 beyond Hxk2 phosphorylation, the proteomic consequences of TDA1 deficiency were investigated by difference gel electrophoresis (2D-DIGE) comparing a wild type and a Δtda1 deletion mutant. To additionally address possible consequences of glucose repression/derepression, both were grown at 2 % and 0.1 % (w/v) glucose. A total of eight protein spots exhibiting a minimum 2-fold enhanced or reduced fluorescence upon TDA1 deficiency was detected and identified by mass spectrometry. Among the spot identities are – besides the expected Hxk2 – two proteoforms of hexokinase 1 (Hxk1). Targeted proteomics analyses in conjunction with 2D-DIGE demonstrated that TDA1 is indispensable for Hxk2 and Hxk1 phosphorylation at serine 15. Thirty-six glucose-concentration-dependent protein spots were identified. A simple method to improve spot quantification, approximating spots as rotationally symmetric solids, is presented along with new data on the quantities of Hxk1 and Hxk2 and their serine 15 phosphorylated forms at high and low glucose growth conditions. The Δtda1 deletion mutant exhibited no altered growth under high or low glucose conditions or on alternative carbon sources. Also, invertase activity, serving as a reporter for glucose derepression, was not significantly altered. Instead, an involvement of Tda1 in oxidative stress response is suggested.
Project description:Hexokinase 2 (Hxk2) of Saccharomyces cerevisiae is a dual function hexokinase, acting as a glycolytic enzyme and being involved in the transcriptional regulation of glucose-repressible genes. Relief from glucose repression is accompanied by phosphorylation of Hxk2 at serine 15, which has been attributed to the protein kinase Tda1. To explore the role of Tda1 beyond Hxk2 phosphorylation, the proteomic consequences of TDA1 deficiency were investigated by difference gel electrophoresis (2D-DIGE) comparing a wild type and a Δtda1 deletion mutant. To additionally address possible consequences of glucose repression/derepression, both were grown at 2 % and 0.1 % (w/v) glucose. A total of eight protein spots exhibiting a minimum twofold enhanced or reduced fluorescence upon TDA1 deficiency was detected and identified by mass spectrometry. Among the spot identities are – besides the expected Hxk2 – two proteoforms of hexokinase 1 (Hxk1). Targeted proteomics analyses in conjunction with 2D-DIGE demonstrated that TDA1 is indispensable for Hxk2 and Hxk1 phosphorylation at serine 15. Thirty-six glucose-concentration-dependent protein spots were identified. A simple method to improve spot quantification, approximating spots as rotationally symmetric solids, is presented along with new data on the quantities of Hxk1 and Hxk2 and their serine 15 phosphorylated forms at high and low glucose growth conditions. The Δtda1 deletion mutant exhibited no altered growth under high or low glucose conditions or on alternative carbon sources. Also, invertase activity, serving as a reporter for glucose derepression, was not significantly altered. Instead, an involvement of Tda1 in oxidative stress response is suggested.
Project description:We investigated the acetylation of H3K27, in normal condition and after stimulation of EGF and before or after the depletion of INTS11. Additionally, we examined transcription by sequencing the chromatin-bound fraction of RNA and by fractionating total RNA into polyadenylated and non-polyadenylated compartement. Comparison of the genome wide profiles of H3K27ac and RNA in HeLa cells
Project description:To understand how integration of multiple data types can help decipher cellular responses at the systems level, we analyzed the mitogenic response of human mammary epithelial cells to epidermal growth factor (EGF) using whole genome microarrays, mass spectrometry-based proteomics and large-scale western blots with over 1000 antibodies. A time course analysis revealed significant differences in the expression of 3172 genes and 596 proteins, including protein phosphorylation changes measured by western blot. Integration of these disparate data types showed that each contributed qualitatively different components to the observed cell response to EGF and that varying degrees of concordance in gene expression and protein abundance measurements could be linked to specific biological processes. Networks inferred from individual data types were relatively limited, whereas networks derived from the integrated data recapitulated the known major cellular responses to EGF and exhibited more highly connected signaling nodes than networks derived from any individual dataset. While cell cycle regulatory pathways were altered as anticipated, we found the most robust response to mitogenic concentrations of EGF was induction of matrix metalloprotease cascades, highlighting the importance of the EGFR system as a regulator of the extracellular environment. These results demonstrate the value of integrating multiple levels of biological information to more accurately reconstruct networks of cellular response. Keywords: time-course analysis Synchronized human mammary epithelial cells were stimulated into mitosis using epidermal growth factor and samples were harvested at 1, 4, 8, 13, 18 and 24hrs for parallel analysis by microarray, global proteomics and western blot analysis.
Project description:We investigated the acetylation of H3K27, in normal condition and after stimulation of EGF and before or after the depletion of INTS11. Additionally, we examined transcription by sequencing the chromatin-bound fraction of RNA and by fractionating total RNA into polyadenylated and non-polyadenylated compartement.
Project description:Translatome analysis by sucrose gradient centrifugation of cell lysates followed by microarray profiling of the polysomal and subpolysomal RNA fractions represents a way of both studying translational control networks and better approximating the proteomic representation of cells. It is an established notion that translational control takes place essentially at the translation initiation level, therefore the variation in abundance of a given mRNA species on polysomes can be directly related to the variation in abundance of the corresponding protein. Comparison of translatome profile changes with corresponding transcriptome profile changes can provide a measure of the degree of concordance between cellular controls affecting mRNA abundance and cellular controls affecting mRNA availability to translation. To provide a direct experimental evaluation of the phenomenon, we decided to study a classical example of transcriptional reprogramming of gene expression: Epidermal Growth Factor (EGF) treatment. This stimulus triggers a well known chain of intracellular transduction events, ultimately resulting in a multifaceted phenotypic spectrum of changes with prevalent induction of cell growth and proliferation. We subjected HeLa cells to serum starvation for 12h and then we added EGF at final concentration of 1 μg/ml, profiling before and after 40 minutes of treatment the transcriptome, the translatome, coming from the polysomal pool of mRNAs after sucrose gradient separation, and also the mRNA content of the subpolysomal pool, expected not to be actively translated. Keywords: translatome profiling, polysomal profiling, polysomal RNA, translational control, translational profiling, polysome profiling, post-transcriptional regulation, EGF starvation release. The comparison between transcriptional and polysomal profiling was used for the discovery of general and mRNA-specific changes in the translation state of the serum starved HeLa cells transcriptome in response to EGF stimulus. To identify translationally regulated mRNA molecules, gene expression signals derived from the polysomal and subpolysomal RNA populations were compared by microarrays analysis to those obtained from unfractionated total RNAs. Polysomal RNA, subpolysomal RNA and total RNA were isolated from HeLa cells serum starved and treated with EGF. Cells lysates were collected before (t = 0 min) and after (t = 40 min) EGF treatment. All experiments were run in triplicates.