Human METTL18 is a histidine-specific methyltransferase that targets RPL3 and affects ribosome biogenesis and function
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ABSTRACT:
PROVIDER: PRJNA610254 | ENA |
REPOSITORIES: ENA
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Project description:Methylation is a common post-translational modification that occurs primarily on lysine and arginine, but also on some other residues, such as histidine. METTL18 is the last uncharacterized member of a group of human methyltransferases (MTases) that mainly exert lysine methylation, and here we set out to elucidate its function. We found METTL18 to be a nuclear protein that contains a functional nuclear localization signal and accumulates in nucleoli. Recombinant METTL18 methylated a single protein in nuclear extracts and in isolated ribosomes from METTL18 knock-out (KO) cells. This protein was identified as 60S ribosomal protein L3 (RPL3), and we also performed an RPL3 interactomics screen and identified METTL18 as the most significantly enriched MTase. Protein mass spectrometry and amino acid analyses revealed that His-245 in RPL3 carries a 3-methylhistidine (3MH; also referred to as t-methylhistidine) modification, which was absent in METTL18 KO cells. In addition, both recombinant and endogenous METTL18 were found to be monomethylated at His-154, likely resulting from auto-methylation, and further corroborating METTL18 as a histidine-specific MTase. Finally, METTL18 KO cells displayed altered pre-rRNA processing, decreased polysomes formation and codon-specific changes in mRNA translation, indicating that METTL18-mediated methylation of RPL3 is important for optimal ribosome biogenesis and function. In conclusion, we have here established METTL18 as the second human histidine-specific protein MTase, and demonstrated its functional relevance.
2021-02-28 | GSE146364 | GEO
Project description:In addition to predominant protein methylation on lysine and arginine residues, histidine also serves as a substrate for the modification. However, a limited number of enzymes responsible for this modification has been reported. Moreover, the biological mission of the histidine methylation has remained poorly understood. Here, we reported that human METTL18 is a histidine methyltransferase for ribosomal protein RPL3 and that the modification specifically slows ribosome traverse on tyrosine codons, allowing proper folding of synthesized proteins. Harnessing in vitro methylation assay with methyl-donor analogue and quantitative mass spectrometry, we identified that His245 of RPL3 is methylated at τ-N position by METTL18. Structural comparison of the modified and unmodified ribosomes showed the stoichiometric modification and suggested its role in translation tuning. Indeed, genome-wide ribosome profiling revealed the suppressed ribosomal translocation at tyrosine codons by RPL3 methylation. Because the slower elongation provides enough time for nascent protein folding, RPL3 methylation protects cells from cellular aggregation of Tyr-rich proteins. Our results reveal histidine methylation as an example of “ribosome code”, which ensures proteome integrity in cells.
2022-06-15 | GSE179854 | GEO
Project description:Protein methylation occurs predominantly on lysine and arginine residues, but histidine also serves as a substrate for the modification. However, a limited number of enzymes responsible for this modification have been reported. Moreover, the biological role of histidine methylation has remained poorly understood. Here, we report that human METTL18 is a histidine methyltransferase for the ribosomal protein RPL3 and that the modification specifically slows ribosome traverse on tyrosine codons, allowing the proper folding of synthesized proteins. By performing an in vitro methylation assay with a methyl donor analog and quantitative mass spectrometry, we found that His245 of RPL3 is methylated at the τ-N position by METTL18. Structural comparison of the modified and unmodified ribosomes showed stoichiometric modification and suggested a role in translation tuning. Indeed, genome-wide ribosome profiling revealed suppressed ribosomal translocation at tyrosine codons by RPL3 methylation. Because the slower elongation provides enough time for nascent protein folding, RPL3 methylation protects cells from the cellular aggregation of Tyr-rich proteins. Our results reveal histidine methylation as an example of a “ribosome code” that ensures proteome integrity in cells.
2022-06-15 | GSE200172 | GEO
Project description: Not available
| S-EPMC8034639 | biostudies-literature
Project description:METTL18-mediated histidine methylation on RPL3 modulates translation elongation for proteostasis maintenance
| PRJNA745343 | ENA
Project description:METTL18-mediated histidine methylation on RPL3 modulates translation elongation for proteostasis maintenance.
| PRJNA823531 | ENA
Project description:Lytic polysaccharide monooxygenases (LPMOs) are oxidative enzymes that help break down lignocellulose, making them highly attractive for improving biomass utilization in biotechnological purposes. The catalytically essential N-terminal histidine (His1) of LPMOs is post-translationally modified by methylation in filamentous fungi to protect them from auto-oxidative inactivation, however, the responsible methyltransferase enzyme is unknown. Using mass-spectrometry-based quantitative proteomics in combination with systematic CRISPR/Cas9 knockout screening in Aspergillus nidulans, we identified the N-terminal histidine methyltransferase (NHMT) encoded by the gene AN4663. Targeted proteomics confirmed that NHMT was solely responsible for His1 methylation of LPMOs. NHMT is predicted to encode a unique seven-transmembrane segment anchoring a soluble methyltransferase domain. Co-localization studies showed endoplasmic reticulum residence of NHMT and co-expression in the industrial production yeast Komagataella phaffii with LPMOs resulted in His1 methylation of the LPMOs. This demonstrates the biotechnological potential of recombinant production of proteins and peptides harbouring this unique post-translational modification.
2023-07-14 | PXD037734 | Pride
Project description:The methylation of histidine residues is increasingly found to be both prevalent throughout the proteome, and also relevant to human disease. Hpm1p mono-methylates H243 in the ribosomal protein Rpl3 and represents the only histidine methyltransferase in Saccharomyces cerevisiae. Interestingly, the hpm1 deletion strain is highly pleiotropic, with many extra-ribosomal phenotypes including improved growth rates in alternative carbon sources. Here we aimed to understand how methylation of one histidine in one ribosomal protein could result in such diverse phenotypes by combining targeted mass spectrometry, growth assays, quantitative proteomics and cross-linking mass spectrometry. We confirmed the localisation and stoichiometry of the H243 site, found unreported sensitivities of Δhpm1 yeast to non-ribosomal stressors, and identified thirty differentially-abundant proteins upon hpm1 knockout, most with clear links to the coordination of sugar metabolism. We adapted the emerging technique of quantitative large scale cross-linking mass spectrometry for use in budding yeast, which resulted in the identification of 1,267 unique in vivo lysine-lysine pairs. By reproducibly monitoring over 350, we detected changes to membrane protein structure, chromatin compaction, and mitochondrial protein-protein interactions, independently of changes in protein abundance themselves. Taken together, these studies reveal a clear role for Hpm1p in the coordination of sugar metabolism, contextualise the deletion strain’s pleiotropy and illustrate how cross-linking mass spectrometry can generate mechanistic insights into complex cellular processes.
2022-08-12 | PXD027953 | Pride
Project description:The Mtq2-Trm112 methyltransferase is known to modify the translational eukaryotic release factor eRF1 on the glutamine side chain of a universally conserved GGQ motif, which is essential to translation termination. The exact role of eRF1 methylation remains unknown. As the deletion of MTQ2 leads to severe growth impairment in S. cerevisiae, we have investigated its role further. Here we report an unexpected function of Mtq2 in ribosome biogenesis. We reveal that Mtq2 is part of nuclear precursor ribosomes to 60S subunits, and we demonstrate that its catalytic activity is required for the stable production of mature 5.8S and 25S rRNAs and for pre-60S export. Consistently, in the absence of Mtq2 function pre-60S subunits enriched in the export factors Nmd3 and Arx1 accumulate in the nucleus. We conclude that, in addition to its role as a translation terminator modification enzyme, Mtq2 is a ribosome assembly factor which is important for late-stage large ribosomal subunit formation.
2020-10-12 | PXD018733 | Pride
Project description:Exploring the interactome of human RPL3 by MS-based proteomics.
2021-09-08 | PXD016055 | Pride