Project description:RNA-binding proteins (RBPs) play pivotal roles in directing RNA fate and function. Yet the current annotation of RBPs is largely limited to proteins carrying known RNA-binding domains. To systematically reveal dynamic RNA-protein interactions, we surveyed the human proteome by a protein array-based approach and identified 671 proteins with RNA-binding activity. Among these proteins, 525 lack annotated RNA-binding domains and are enriched in transcriptional and epigenetic regulators, metabolic enzymes, and small GTPases. Using an improved CLIP (crosslinking and immunoprecipitation) method, we performed genome-wide target profiling of isocitrate dehydrogenase 1 (IDH1), a novel RBP. IDH1 binds to thousands of RNA transcripts with enriched functions in transcription and chromatin regulation, cell cycle and RNA processing. Purified IDH1, but not an oncogenic mutant, binds directly to GA- or AU-rich RNA that are also enriched in IDH1 CLIP targets. Our study provides useful resources of unconventional RBPs and IDH1-bound transcriptome, and convincingly illustrates, for the first time, the in vivo and in vitro RNA targets and binding preferences of IDH1, revealing an unanticipated complexity of RNA regulation in diverse cellular processes.
Project description:RNA-binding proteins (RBPs) play pivotal roles in directing RNA fate and function. Yet the current annotation of RBPs is largely limited to proteins carrying known RNA-binding domains. To systematically reveal dynamic RNA-protein interactions, we surveyed the human proteome by a protein array-based approach and identified 671 proteins with RNA-binding activity. Among these proteins, 525 lack annotated RNA-binding domains and are enriched in transcriptional and epigenetic regulators, metabolic enzymes, and small GTPases. Using an improved CLIP (crosslinking and immunoprecipitation) method, we performed genome-wide target profiling of isocitrate dehydrogenase 1 (IDH1), a novel RBP. IDH1 binds to thousands of RNA transcripts with enriched functions in transcription and chromatin regulation, cell cycle and RNA processing. Purified IDH1, but not an oncogenic mutant, binds directly to GA- or AU-rich RNA that are also enriched in IDH1 CLIP targets. Our study provides useful resources of unconventional RBPs and IDH1-bound transcriptome, and convincingly illustrates, for the first time, the in vivo and in vitro RNA targets and binding preferences of IDH1, revealing an unanticipated complexity of RNA regulation in diverse cellular processes.
Project description:This SuperSeries is composed of the following subset Series: GSE38356: The mRNA-bound proteome and its global occupancy profile on protein-coding transcripts [RNA-seq] GSE38201: The mRNA-bound proteome and its global occupancy profile on protein-coding transcripts [PAR-CLIP] GSE38355: The mRNA-bound proteome and its global occupancy profile on protein-coding transcripts [protein occupancy profiling] Refer to individual Series
Project description:Gain-of-function mutations of isocitrate dehydrogenase 1 (IDH1) lead to neomorphic enzymatic activities and the production of oncometabolite R-2-hydroxyglutarate (2-HG), contributing to the tumorigenesis of several human cancers. It has been shown that fatty acid biosynthesis is required for the growth of IDH1 mutant tumors, but the underlining mechanisms are unclear. We developed new activity-based chemical probes to study protein autopalmitoylation, and identified that the oncogenic IDH1 (R132H) mutant is uniquely autopalmitoylated at cysteine 269 (C269), which is not observed in the wild type IDH1. Molecular dynamic simulations suggest that palmitoylation of the R132H mutant could occur in a hydrophobic pocket, and enhance its dimerization, consistent with our experimental results. In addition, in vitro autopalmitoylated recombinant IDH1 mutant protein showed enhanced enzymatic activities. In cells expressing IDH1 (R132H) mutant, exogenous fatty acids enhance mutant IDH1 activities through promoting C269 autopalmitoylation, and loss of C269 palmitoylation reverses mutant-induced metabolic reprograming and hypermethylation phenotypes, and impairs cell transformation. Interestingly, a clinical IDH1 mutant inhibitor (LY3410738) strongly inhibits autopalmitoylation by binding to the lipid-binding pocket and covalently modifying C269. Our study reveals that autopalmitoylation conferred by oncogenic IDH1 R132H mutation links fatty acid metabolism to the regulation of IDH1 mutant activities, and is a druggable vulnerability of IDH1 mutant cancers.
Project description:In the present study, we applied a quantitative MS-based strategy to characterize the proteome and phosphoproteome in HRAS- or IDH1-driven glioma cells. We describe the driving roles of the MEK and PI3K signaling pathways in RAS-NHA cells, and uncover oncogenic signaling in other pathways. We highlight the interplay between the signaling cascades and show that inhibition of MEK and PI3K reverses phosphorylation signaling patterns driven by oncogenic RAS overexpression. Applying a histone hybrid chemical labeling method and high-resolution MS, we identified significant histone methylation, acetylation, and butyrylation changes in IDH1mut-NHA cells. Our results suggest a global transcriptional repressive state, consistent with the down-regulation of the proteome, transcriptome, and the DNA hyper-methylated state in IDH1mut-NHA cells. We provide a unique resource of altered proteins, phosphosites, and histone PTMs in RAS and IDH1 mutant astrocytoma cell lines, providing insight into oncogenesis in glioma beyond the transcriptomic level.
Project description:Protein-RNA interactions are fundamental to core biological processes, such as mRNA splicing, localization, degradation and translation. We developed a photoreactive nucleotide-enhanced UV crosslinking and oligo(dT) purification approach to identify the mRNA-bound proteome using quantitative proteomics and to display the protein occupancy on mRNA transcripts by next-generation sequencing. Application to a human embryonic kidney cell line identified close to 800 proteins. Close to one third of these proteins, were neither previously annotated nor could be functionally predicted to bind RNA. Protein occupancy profiling provides a transcriptome-wide catalog of potential cis-regulatory regions on mammalian mRNAs and showed that large stretches in 3' UTRs can be contacted by the mRNA-bound proteome, with numerous putative binding sites in regions harboring disease-associated nucleotide polymorphisms. Our observations indicate the presence of a large number of unexpected mRNA-binders with novel molecular functions participating in combinatorial post-transcriptional gene-expression networks. PARCLIP was performed as in Hafner et al. 2010 Cell 141, 129M-bM-^@M-^S141, with HEK293 cell lines stably expressing HIS/FLAG/HA-tagged ALKBH5, C17orf85, C22orf28, CAPRIN1, and ZC3H7B. We used 4-thiouridine (4SU) to enhance the crosslink and generated two PAR-CLIP cDNA libraries per protein.
Project description:Protein-RNA interactions are fundamental to core biological processes, such as mRNA splicing, localization, degradation and translation. We developed a photoreactive nucleotide-enhanced UV crosslinking and oligo(dT) purification approach to identify the mRNA-bound proteome using quantitative proteomics and to display the protein occupancy on mRNA transcripts by next-generation sequencing. Application to a human embryonic kidney cell line identified close to 800 proteins. Close to one third of these proteins, were neither previously annotated nor could be functionally predicted to bind RNA. Protein occupancy profiling provides a transcriptome-wide catalog of potential cis-regulatory regions on mammalian mRNAs and showed that large stretches in 3' UTRs can be contacted by the mRNA-bound proteome, with numerous putative binding sites in regions harboring disease-associated nucleotide polymorphisms. Our observations indicate the presence of a large number of unexpected mRNA-binders with novel molecular functions participating in combinatorial post-transcriptional gene-expression networks.
Project description:Protein-RNA interactions are fundamental to core biological processes, such as mRNA splicing, localization, degradation and translation. We developed a photoreactive nucleotide-enhanced UV crosslinking and oligo(dT) purification approach to identify the mRNA-bound proteome using quantitative proteomics and to display the protein occupancy on mRNA transcripts by next-generation sequencing. Application to a human embryonic kidney cell line identified close to 800 proteins. Close to one third of these proteins, were neither previously annotated nor could be functionally predicted to bind RNA. Protein occupancy profiling provides a transcriptome-wide catalog of potential cis-regulatory regions on mammalian mRNAs and showed that large stretches in 3' UTRs can be contacted by the mRNA-bound proteome, with numerous putative binding sites in regions harboring disease-associated nucleotide polymorphisms. Our observations indicate the presence of a large number of unexpected mRNA-binders with novel molecular functions participating in combinatorial post-transcriptional gene-expression networks.