Project description:Methionine plays a critical role in various biological and cell regulatory processes, making its chemoproteomic profiling indispensable for exploring its functions and potential in protein therapeutics. However, the advancement of methionine chemoproteomics is currently hindered by the scarcity of efficient labeling strategies. Methionine exhibits high kinetic reactivity and undergoes rapid oxidation due to the lower energy gap between Lowest Unoccupied Molecular Orbital (LUMO) and Highest Occupied Molecular Orbital (HOMO). Building on this unique high reactivity of methionine (Met), we introduce Copper(I)-Nitrene Platform (CuNiP) for robust, and selective labeling of Met to generate highly stable sulfonyl sulfimide conjugates under physiological conditions. We demonstrated the versatile proficiency of CuNiP to label methionine in a wide range of bioactive peptides, intact proteins (6.5-79.5 kDa) independent of molecular weight and 3D structures and proteins in complex cell lysate mixtures with varying payloads. Leveraging nitrene reactivity-based probes, we have discovered an array of new, previously undiscovered, ligandable proteins and sites harboring hyperreactive methionine within the landscape of the human proteome. Crucially, we employed CuNiP for live cell chemoproteomic profiling of methionine in breast (T47D) and prostate cancer (LnCap) cell lines, observing minimal cytotoxic effects and achieving dose-dependent labeling. Confocal imaging further revealed the spatial distribution of modified proteins within cell membrane, cytoplasm, and nucleus, underscoring the platform's potential in profiling the cellular interactome. This breakthrough, with its insights into live cell methionine labeling will deepen our understanding of protein biochemistry and also pioneers a transformative pathway in drug discovery.
Project description:<p>We generated a collection of patient-derived pancreatic normal and cancer organoids. We performed whole genome sequencing, targeted exome sequencing, and RNA sequencing on organoids as well as matched tumor and normal tissue if available. This dataset is a valuable resource for pancreas cancer researchers, and those looking to compare primary tissue to organoid culture. In our linked publication, we show that pancreatic cancer organoids recapitulate the mutational spectrum of pancreatic cancer. Furthermore, RNA sequencing of organoids demonstrates the presence of both transcriptional subtypes of pancreas cancer.</p>
Project description:The genome-wide transcriptional response of S. cerevisiae cells upon transfer to methionine-restricted media is investigated. DHO strain (BY4742 background) was cultivated batch-wise in SDC media at 30C and 180 rpm up to mid-exponential phase (OD600 ~ 0.6). The cells of the main culture were divided in three aliquots at the mid-exponential phase, centrifuged at 6000 rpm for 5 min, washed twice with deionized and distilled sterile water prior to their transfer to the treatment media. Treatment media comprised of SDC + 0.75% methionine for the methionine-restricted case while SDC is used for the control case. Sample collection for transcriptional profiling was done at the 2nd hour of the transfer. The experiments were carried out in biological triplicates.
Project description:BSA pooling experiment for methionine content in a segrating diploid potato population (CxE). RNA of constrasting individuals for methionine content are pooled together based on their tuber methionine content and marker association with either or both of the identified QTLs for methionine content
Project description:Targeting altered tumor cell metabolism might provide an attractive opportunity for patients with acute myeloid leukemia (AML). An amino acid dropout screen on primary leukemic stem cells and progenitor populations revealed a number of amino acid dependencies, of which methionine was one of the strongest. By using various metabolite rescue experiments, NMR-based metabolite quantifications and 13C-tracing, polysomal profiling, and ChIP-seq, we identified that methionine is used predominantly for protein translation and to provide methyl groups to histones via S-adenosylmethionine for epigenetic marking. H3K36me3 was consistently the most heavily impacted mark following loss of methionine. Methionine depletion also reduced total RNA levels, enhanced apoptosis and induced a cell cycle block. ROS levels were not increased following methionine depletion and replacement of methionine with glutathione or N-acetylcysteine could not rescue phenotypes, excluding a role for methionine in controlling redox balance control in AML. Although considered to be an essential amino acid, methionine can be recycled from homocysteine. We uncovered that this is primarily performed by the enzyme methionine synthase and only when methionine availability becomes limiting. In vivo, dietary methionine starvation was not only tolerated by mice, but also significantly delayed both cell line and patient-derived AML progression. Finally, we show that inhibition of the H3K36-specific methyltransferase SETD2 phenocopies much of the cytotoxic effects of methionine depletion, providing a more targeted therapeutic approach. In conclusion, we show that methionine depletion is a vulnerability in AML that can be exploited therapeutically, and we provide mechanistic insight into how cells metabolize and recycle methionine.
Project description:We characterize the translational and transcriptional programs induced by MetR and investigate the potential mechanisms through which methionine regulates gene expression, using the budding yeast S. cerevisiae as the model organism. Using ribosomal profiling and RNA-seq, we systematically compared the translational and transcriptional profiles of cells growing in the normal and methionine restricted media. We observed a broad spectrum of gene expression changes in response to MetR, including hundreds of genes whose transcript level and/or translational efficiency changed significantly. These genes fall into specific functional classes that are informative of the physiological state of the cell under MetR. Analysis of ribosome loading patterns of genes with increased translational efficiency suggested mechanisms both similar and different from the canonical model of translational regulation by general amino acid starvation. Analysis of the genes with decreased translational efficiency added support to the thiolation model of translational regulation by methionine. Since MetR extends the lifespan of many species, the list of genes we identified in this study can be good candidates for studying the downstream effectors of lifespan extension.
Project description:Dietary methionine restriction is associated with a reduction in tumor growth in preclinical studies and an increase in lifespan in animal models. The mechanism by which methionine restriction inhibits tumor growth while sparing normal cells is incompletely understood, except for the observation that normal cells can utilize methionine or homocysteine interchangeably (methionine independence) while most cancer cells are strictly dependent on methionine availability. Here, we compared a typical methionine dependent and a rare methionine independent melanoma cell line. We show that replacing methionine, a methyl donor, with homocysteine generally induced hypomethylation in gene promoters. This decrease was similar in methionine dependent versus methionine independent cells. There was only a low level of pathway enrichment, suggesting that the hypomethylation is generic rather than gene specific. Whole proteome and transcriptome were also analyzed. This analysis revealed that contrarily to the effect on methylation, the replacement of methionine with homocysteine had a much greater effect on the transcriptome and proteome of methionine dependent cells than methionine independent cells. Interestingly, the methionine adenosyltransferase 2A (MAT2A), responsible for the synthesis of s-adenosylmethionine from methionine, was equally strongly upregulated in both cell lines. This suggests that the absence of methionine is equally detected but trigger different outcomesin methionine dependent versus independent cells. Our analysis reveals the importance of cell cycle control, DNA damage repair, translation, nutrient sensing, oxidative stress and tight junctions in the cellular response to methionine stress in melanoma.
Project description:Dietary methionine restriction is associated with a reduction in tumor growth in preclinical studies and an increase in lifespan in animal models. The mechanism by which methionine restriction inhibits tumor growth while sparing normal cells is incompletely understood, except for the observation that normal cells can utilize methionine or homocysteine interchangeably (methionine independence) while most cancer cells are strictly dependent on methionine availability. Here, we compared a typical methionine dependent and a rare methionine independent melanoma cell line. We show that replacing methionine, a methyl donor, with homocysteine generally induced hypomethylation in gene promoters. This decrease was similar in methionine dependent versus methionine independent cells. There was only a low level of pathway enrichment, suggesting that the hypomethylation is generic rather than gene specific. Whole proteome and transcriptome were also analyzed. This analysis revealed that contrarily to the effect on methylation, the replacement of methionine with homocysteine had a much greater effect on the transcriptome and proteome of methionine dependent cells than methionine independent cells. Interestingly, the methionine adenosyltransferase 2A (MAT2A), responsible for the synthesis of s-adenosylmethionine from methionine, was equally strongly upregulated in both cell lines. This suggests that the absence of methionine is equally detected but trigger different outcomesin methionine dependent versus independent cells. Our analysis reveals the importance of cell cycle control, DNA damage repair, translation, nutrient sensing, oxidative stress and tight junctions in the cellular response to methionine stress in melanoma.