Project description:We identified RNA binding motif protein 47 (RBM47) as a target gene of transforming growth factor (TGF)-beta in mammary gland epithelial cells (NMuMG cells) that have undergone the epithelial-to-mesenchymal transition (EMT). TGF-beta repressed RBM47 expression in NMuMG cells and lung cancer cell lines. Expression of RBM47 correlated with good prognosis in patients with lung, breast, and gastric cancer. RBM47 suppressed the expression of cell metabolism-related genes, which were the direct targets of nuclear factor erythroid 2-related factor 2 (Nrf2; also known as NFE2L2). RBM47 bound to KEAP1 and Cullin3 mRNAs, and knockdown of RBM47 inhibited their protein expression, which led to enhanced binding of Nrf2 to target genomic regions. Knockdown of RBM47 also enhanced the expression of some Nrf2 activators, p21/CDKN1A and MafK induced by TGF-beta. Both mitochondrial respiration rates and the side population cells in lung cancer cells increased in the absence of RBM47. Our findings, together with the enhanced tumor formation and metastasis of xenografted mice by knockdown of the RBM47 expression, suggested tumor suppressive roles for RBM47 through the inhibition of Nrf2 activity. Effect of shRNA for RBM47 and TGF-beta on gene expression was evaluated by RNA-seq and RBM47-bound RNAs were identified by RIP-seq in A549 cells.
Project description:Mass spectrometry remains an important method for analysis of modified nucleosides ubiquitously present in cellular RNAs, in particular for ribosomal and transfer RNAs that play crucial roles in mRNA translation and decoding. Furthermore, modifications have effect on the lifetimes of nucleic acids in plasma and cells and are consequently incorporated into RNA therapeutics. To provide an analytical tool for sequence characterization of modified RNAs, we developed Pytheas, an open-source software package for automated analysis of tandem MS data for RNA. This dataset contains the analysis of a mixture of S. cerevisiae tRNAs, decorated with a variety of complex RNA modifications.
Project description:Flash proteotyping is a methodology for ultra-fast identification of microorganisns by tandem mass spectrometry. Here, we obtained results on five reference strains and ten new bacterial isolates. The methodology is based on direct sample infusion into the mass spectromete and an original, highly sensitive procedure for data processing and taxonomic identification.
Project description:Naïve and activated T-cells has a different response to antigenic challenge. We examine whether a cytokine like IL-6 induces different responses through the Jak-STAT pathway to affect the functional characteristics of a given CD4 T‑cell subset. We isolated naïve and effector memory (Tem) CD4 T-cells to investigated STAT1 and STAT3 binding after 1-hour treatment with 20ng/ml IL-6 in the presence of anti-CD3/CD28.
Project description:BAX is a pro-apoptotic BCL-2 protein that resides in the cytosol as a monomer until triggered by cellular stress to transform into an oligomer that permeabilizes the mitochondria and induces apoptosis. We previously reported the generation of a full-length BAX oligomer (BAXO) that recapitulates pro-apoptotic functionality. Here, we find that full-length BCL-w can be induced to form a symmetric dimer (BCL-wD) that dissociates BAXO, inhibits its mitochondrial translocation, induces its retrotranslocation, and thereby blocks its membrane-porating activity. Structure-function analyses revealed discrete conformational changes upon BCL-w dimerization and reciprocal structural impacts upon BCL-wD and BAXO interaction. SAXS analysis demonstrated that BAXO forms pores by inducing negative Gaussian membrane curvature, which is reversed by positive Gaussian curvature exerted by BCL-wD. Our studies reveal an additional mechanism of apoptotic regulation mediated by the protein and membrane interactions of higher-order BCL-2 family multimers, redefining the “point of no return” for BAX-mediated apoptosis.
Project description:This work aimed to improve sensitivity of targeted detection by orbitrap mass spectrometers. Co-isolation of contaminant ions was identified as the major factor limiting sensitivity, and LOD of both PRM and accumulated precursor ion scanning (AIM) was improved by increased chromatographic resolution.
Project description:Top-down analysis of intact proteins by mass spectrometry provides an ideal platform for comprehensive proteoform characterization, in particular, for the identification and localization of post-translational modifications (PTM) co-occurring on a protein. One of the main bottlenecks in top-down proteomics is insufficient protein sequence coverage caused by incomplete protein fragmentation. Based on previous work on peptides, increasing sequence coverage and PTM localization by combining sequential ETD and HCD fragmentation in a single fragmentation event, we hypothesized that protein sequence coverage and phospho-proteoform characterization could be equally improved by this new dual fragmentation method termed EThcD, recently been made available on the Orbitrap Fusion. Here, we systematically benchmark the performance of several (hybrid) fragmentation methods for intact protein analysis on an Orbitrap Fusion, using as a model system a 17.5 kDa N-terminal fragment of the mitotic regulator Bora. During cell division Bora becomes multiply phosphorylated by a variety of cell cycle kinases, including Aurora A and Plk1, albeit at distinctive sites. Here, we monitor the phosphorylation of Bora by Aurora A and Plk1, analyzing the generated distinctive phospho-proteoforms by top-down fragmentation. We show that EThcD and ETciD on a Fusion are feasible and capable of providing richer fragmentation spectra compared to HCD or ETD alone, increasing protein sequence coverage, and thereby facilitating phosphosite localization and the determination of kinase specific phosphorylation sites in these phospho-proteoforms.
Project description:Triple-negative breast cancer (TNBC) is characterized by lack of receptors, estrogen (ER), progesterone, and Her2, and standard receptor-targeted therapies are ineffective. FOXC1, a transcriptional factor aberrantly overexpressed in many cancers, drives growth, metastasis, and stem-cell-like properties in TNBC. However, the molecular function of FOXC1 is unknown, partly due to heterogeneity of TNBC. Here, we show that although FOXC1 regulates many cancer hallmarks in TNBC, its function is varied in different cell lines, highlighted by the differential response to CDK4/6 inhibitors upon FOXC1 loss. Despite this functional heterogeneity, we show that FOXC1 regulates key oncogenes and tumor suppressors and identify a set of core FOXC1 peaks conserved across TNBC cell lines. We identify the ER-associated and drug-targetable nuclear receptor NR2F2 as a cofactor of FOXC1. Finally, we show that core FOXC1 targets in TNBC are parallelly regulated by the pioneer factor FOXA1 and the nuclear receptor NR2F2 in ER+ breast cancer.
Project description:Stomata pores are surrounded by a pair of guard cells in the epidermis in plants. Stomata apature is controlled by environmental factors. Stomata opening is also enhanced by introduction of SOC1-GFP driven by GC1 promoter in phot1 phot2 double mutants (pGC1::SOC1-GFP/ phot1 phot2). Epidermis including guard cells were isolated from phot1 phot2 and pGC1::SOC1-GFP/phot1 phot2 and gene expression were analyzed. phot1-5 phot2-1 in gl1 background (phot1 phot2) and pGC1::SOC1-GFP/phot1 phot2 were grown under 16 h light / 8h dark, constant 22?C conditions for 4 to 5 weeks. Epidermis including guard cells were isolated from leaves of these plants. Three biological replicates were used.