GO:0035657 eRF1 methyltransferase complex: Components, Assembly and Research Methods, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0035657 (eRF1 methyltransferase complex) is a cellular component required for methylation of a glutamine residue in the translation release factor eRF1.
• In Saccharomyces cerevisiae, the complex consists of at least the catalytic subunit Mtq2p (Ydr140w) and the activator Trm112p (Ynr046w) [2, 7].
• The human ortholog is the HEMK2 (N6amt1)-TRMT112 complex, which methylates the GGQ motif of eRF1 [1, 4].
• Methylation of eRF1 Gln is essential for efficient translation termination and for large ribosomal subunit biogenesis [5, 7].
• Trm112p is a plurifunctional zinc finger protein that activates multiple methyltransferases, including Mtq2p [2, 3, 8].
• Dysregulation of eRF1 methylation is linked to cancer, ribosomopathies, and neurological disorders [1, 5].
Description
The eRF1 methyltransferase complex (GO:0035657) is a protein complex that catalyzes the methylation of a conserved glutamine residue in the eukaryotic release factor eRF1. This modification occurs within the universally conserved GGQ motif of eRF1 and is critical for efficient translation termination. In Saccharomyces cerevisiae, the complex is composed of the catalytic subunit Mtq2p (encoded by YDR140w) and the essential zinc finger protein Trm112p (encoded by YNR046w) [2, 7]. The human counterpart, HEMK2 (also known as N6amt1) in complex with TRMT112, performs the same modification on human eRF1 [1, 4]. Researchers study GO:0035657 because it sits at the intersection of translation termination, ribosome biogenesis, and cellular stress responses. Loss of Mtq2-Trm112 activity leads to defects in large ribosomal subunit assembly and impaired translation termination, underscoring its importance for protein synthesis fidelity. Moreover, mutations or altered expression of the human complex have been implicated in cancer and developmental disorders. Understanding the structure, assembly, and regulation of this complex provides insights into fundamental translation mechanisms and potential therapeutic targets. This article integrates authoritative QuickGO data with verified PubMed literature to provide a comprehensive overview of the eRF1 methyltransferase complex, its components, molecular function, and relevance to human disease. It also outlines experimental strategies, including CRISPR-based models, for investigating this complex.
eRF1 methyltransferase complex At A Glance
| GO ID | GO:0035657 |
|---|---|
| GO term | eRF1 methyltransferase complex |
| Ontology | cellular_component |
| Synonym | eRF1 MTase complex |
| Major function | Methylation of a glutamine residue in eRF1 |
| Subunits (yeast) | Mtq2p (catalytic), Trm112p (activator) |
| Subunits (human) | HEMK2/N6amt1 (catalytic), TRMT112 (activator) |
| Substrate | eRF1 (eukaryotic release factor 1) |
| Conservation | Present in eukaryotes from yeast to humans |
What Is GO:0035657?
The eRF1 methyltransferase complex is a protein complex that methylates a specific glutamine residue in the translation release factor eRF1. In yeast, this complex minimally comprises the methyltransferase Mtq2p and its activator Trm112p. The complex is required for the post-translational modification of eRF1, which is essential for optimal translation termination and ribosome biogenesis.
Why Is eRF1 methyltransferase complex Important in Cell Biology?
The eRF1 methyltransferase complex is essential for accurate and efficient translation termination, a fundamental step in protein synthesis. Methylation of the GGQ motif in eRF1 by this complex ensures proper recognition of stop codons and release of nascent polypeptides. Beyond termination, the complex is required for large ribosomal subunit biogenesis, linking it to ribosome assembly and cellular growth control. Dysregulation of the human complex has been associated with cancer and other diseases, making it a potential target for therapeutic intervention.
• Ensures efficient translation termination by modifying the GGQ motif of eRF1.
• Required for large ribosomal subunit biogenesis in yeast.
• Trm112p is a shared activator of multiple methyltransferases, integrating diverse cellular processes [3, 8].
• Human HEMK2-TRMT112 complex is implicated in cancer and developmental disorders.
• Provides a model for studying protein methyltransferase complexes and their regulation.
• Loss of function leads to translation defects and growth impairment.
• Potential target for antibiotics or anticancer drugs.
• Involved in cellular stress responses and translational reprogramming.
• Structural insights inform drug design and understanding of methyltransferase mechanisms [1, 4].
• Connects translation termination to ribosome quality control and disease.
What Happens During eRF1 methyltransferase complex?
Recognition and Binding of eRF1
In simple terms: The complex grabs onto the release factor eRF1 to prepare it for modification.
The eRF1 methyltransferase complex specifically recognizes the conserved GGQ motif of eRF1. In yeast, the catalytic subunit Mtq2p binds eRF1, while the activator Trm112p stabilizes the complex and enhances catalytic activity [2, 7]. Structural studies of the human HEMK2-TRMT112 complex reveal that TRMT112 interacts with the catalytic domain of HEMK2 to facilitate substrate binding [1, 4].
Methyl Transfer to Glutamine
In simple terms: A methyl group is attached to a specific glutamine in eRF1.
The catalytic subunit Mtq2p (or HEMK2 in humans) uses S-adenosylmethionine (SAM) as a methyl donor to transfer a methyl group to the glutamine residue within the GGQ motif of eRF1. This methylation is essential for eRF1 function, as unmethylated eRF1 exhibits reduced translation termination efficiency.
Role of Trm112p as an Activator
In simple terms: Trm112p is a helper protein that turns on the methyltransferase.
Trm112p is a 15-kDa zinc finger protein that is essential for the activity of Mtq2p and other methyltransferases. It forms a tight complex with Mtq2p, and this interaction is required for methylation of eRF1 in vivo [2, 8]. Trm112p also activates tRNA methyltransferases, highlighting its plurifunctional role.
Impact on Translation Termination and Ribosome Biogenesis
In simple terms: Methylation helps stop protein synthesis correctly and build ribosomes.
Methylated eRF1 efficiently recognizes stop codons and promotes peptide release. Additionally, the catalytic activity of the Mtq2-Trm112 complex is required for large ribosomal subunit biogenesis, as loss of Mtq2 leads to defects in 60S subunit assembly. This dual role connects translation termination to ribosome production.
Key Genes Involved in GO:0035657 eRF1 methyltransferase complex
The following genes and proteins are key components or regulators of the eRF1 methyltransferase complex across species.
| Gene | Major Role | Research Relevance |
|---|---|---|
| MTQ2 (YDR140w) | Catalytic subunit of the yeast eRF1 methyltransferase complex | Essential for eRF1 methylation and translation termination |
| TRM112 (YNR046w) | Activator subunit, zinc finger protein | Required for Mtq2p activity and stability [2, 8] |
| HEMK2 (N6amt1) | Human catalytic subunit | Methylates human eRF1; implicated in cancer [1, 4] |
| TRMT112 | Human activator subunit | Essential for HEMK2 function [1, 4] |
| eRF1 (ETF1) | Substrate release factor | GGQ motif methylation is critical for termination |
| TRM9 | tRNA methyltransferase activated by Trm112p | Shares activator with Mtq2p |
| TRM11 | tRNA methyltransferase activated by Trm112p | Illustrates plurifunctional role of Trm112p |
| BUD23 | Ribosome biogenesis factor activated by Trm112p | Links Trm112p to ribosome assembly |
| N6amt1 | Alternative name for HEMK2 | Structural studies of human complex |
| Ynr046w | Systematic name for Trm112p | Original identification in yeast |
| Ydr140w | Systematic name for Mtq2p | Original identification in yeast |
| eRF3 | Release factor partner of eRF1 | Cooperates in termination |
| RPS3 | Ribosomal protein | Potential downstream target of termination defects |
| RPL25 | Ribosomal protein | Large subunit biogenesis affected by Mtq2 loss |
| SAM | Methyl donor | Cofactor for methyl transfer |
| SAH | Byproduct of methylation | Feedback inhibitor of methyltransferases |
| TRMT112 | Human Trm112 ortholog | Activator of HEMK2 |
How Is eRF1 methyltransferase complex Regulated?
The eRF1 methyltransferase complex is regulated at multiple levels. The availability of the activator Trm112p is a key determinant, as it is shared among several methyltransferases and its expression levels can influence complex formation [3, 8]. In yeast, Trm112p is essential and its depletion affects both tRNA and protein methylation. The catalytic activity of Mtq2p is also dependent on S-adenosylmethionine (SAM) levels, linking methylation to cellular metabolism. Furthermore, the complex's role in ribosome biogenesis suggests that its activity may be coordinated with ribosomal stress responses. In humans, HEMK2 expression can be regulated by oncogenic signaling pathways, although specific regulators remain to be fully elucidated.
eRF1 methyltransferase complex and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| HEMK2 | Cancer (overexpression) | Knockout and overexpression in cancer cell lines |
| TRMT112 | Cancer, developmental disorders | Knockout in human cell lines |
| MTQ2 | Ribosomopathy (yeast model) | Yeast knockout and point mutants |
| eRF1 (ETF1) | Translation termination defects | Point mutation of GGQ motif |
| TRM112 | Ribosomopathy, translation defects | Yeast knockout and humanized models |
Cancer
The human eRF1 methyltransferase complex, HEMK2-TRMT112, has been implicated in cancer. HEMK2 (N6amt1) is overexpressed in several tumor types, and its methyltransferase activity may contribute to tumor progression by modulating translation termination and ribosome biogenesis. Structural studies provide a basis for designing inhibitors that could target HEMK2 in cancer therapy [1, 4].
Ribosomopathies
Defects in large ribosomal subunit biogenesis are a hallmark of ribosomopathies. The Mtq2-Trm112 complex is required for 60S subunit assembly in yeast, and its loss leads to ribosome biogenesis defects. This suggests that mutations in human HEMK2 or TRMT112 could contribute to ribosomopathy-like phenotypes, although direct evidence is still emerging.
Neurological Disorders
Proper translation termination is critical for neuronal function. Dysregulation of eRF1 methylation could lead to aberrant protein synthesis and has been hypothesized to play a role in neurodegenerative diseases, though direct links remain to be established.
From eRF1 methyltransferase complex-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| What is the effect of Mtq2 loss on translation termination? | MTQ2 knockout yeast strains |
| How does Trm112p activate Mtq2p? | Point mutations in TRM112 zinc finger domain |
| Does eRF1 methylation affect ribosome biogenesis? | Knockout of MTQ2 in yeast followed by polysome profiling |
| What is the role of HEMK2 in cancer cell proliferation? | HEMK2 knockout and overexpression in human cancer cell lines |
| Can we visualize the complex in live cells? | Tagged knock-in of HEMK2 and TRMT112 with fluorescent proteins |
| What are the downstream targets of eRF1 methylation? | Proteomics and ribosome profiling in knockout models |
How to Study the eRF1 methyltransferase complex Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Ribo-seq | Ribosome occupancy and stalling | Translation termination efficiency |
| Mass spectrometry | Methylation status of eRF1 | Quantification of Gln methylation |
| Cryo-EM | 3D structure of the complex | Subunit interactions and catalytic mechanism |
| Polysome profiling | Ribosome subunit distribution | Large subunit biogenesis defects |
| Western blot | Protein expression levels | Knockout validation |
| Co-immunoprecipitation | Protein-protein interactions | Complex assembly |
| CRISPR screening | Gene essentiality and synthetic lethality | Identifying modifiers of eRF1 methylation |
Ribosome Profiling (Ribo-seq)
Ribo-seq measures ribosome occupancy on mRNAs and can reveal defects in translation termination upon loss of eRF1 methylation. Cells or yeast lacking Mtq2/HEMK2 show increased ribosome stalling at stop codons, which can be quantified by Ribo-seq.
Proteomics and Methylation Analysis
Mass spectrometry-based proteomics can detect the methylation status of eRF1. Immunoprecipitation of eRF1 followed by mass spectrometry allows mapping of the methylated glutamine residue and quantification of methylation levels in wild-type versus mutant cells.
Structural Biology (Cryo-EM, X-ray Crystallography)
Structures of the HEMK2-TRMT112 complex and Mtq2-Trm112 have been solved, providing insights into substrate binding and catalysis. These methods are essential for understanding how the complex recognizes eRF1 and for structure-based drug design [1, 4].
Polysome Profiling
Polysome profiling separates ribosomal subunits and polysomes on sucrose gradients. This method can detect defects in large ribosomal subunit biogenesis in Mtq2 or Trm112 mutants, as shown by altered 60S peak profiles.
How CRISPR Can Be Used to Study GO:0035657 eRF1 methyltransferase complex
Knockout
CRISPR knockout of MTQ2, TRM112, HEMK2, or TRMT112 can abolish eRF1 methylation. These models are used to study translation termination defects, ribosome biogenesis, and cellular growth phenotypes [5, 7]. Knockout cell lines also serve as negative controls for methylation-specific antibodies.
Point Mutation
Point mutations in the catalytic site of Mtq2p or HEMK2 (e.g., disrupting SAM binding) can separate methylation activity from other functions. Similarly, mutating the target glutamine in eRF1 to alanine prevents methylation and mimics loss of the complex.
Knock-in
Knock-in of tagged versions of Mtq2p, Trm112p, HEMK2, or TRMT112 (e.g., FLAG, GFP) allows for affinity purification, imaging, and interaction studies. Knock-in of disease-associated mutations can model human disorders.
Overexpression
Overexpression of HEMK2 or TRMT112 in human cells can increase eRF1 methylation and may promote oncogenic phenotypes. Overexpression models are useful for studying gain-of-function effects and for drug screening.
How EDITGENE Supports eRF1 methyltransferase complex Research
Researchers studying eRF1 methyltransferase complex-related genes often need to determine whether a candidate gene is causally involved in translation termination, ribosome biogenesis, or disease. EDITGENE provides a comprehensive suite of CRISPR-based services to create precisely engineered cell models, enabling functional validation and mechanistic studies.
Contact EDITGENE today to design your custom CRISPR model for eRF1 methyltransferase complex research.
Frequently Asked Questions About eRF1 methyltransferase complex
What is the eRF1 methyltransferase complex?
The eRF1 methyltransferase complex (GO:0035657) is a protein complex that methylates a glutamine residue in the translation release factor eRF1. In yeast, it consists of Mtq2p and Trm112p.
What genes are involved in the eRF1 methyltransferase complex?
Key genes include MTQ2 (YDR140w) and TRM112 (YNR046w) in yeast, and HEMK2 (N6amt1) and TRMT112 in humans [2, 7, 1].
Where is the eRF1 methyltransferase complex located?
It is a cellular component found in the cytoplasm, associated with the translation machinery and ribosomes.
What is the function of Trm112p in the complex?
Trm112p is an activator subunit that binds to Mtq2p and is required for its methyltransferase activity.
How does eRF1 methylation affect translation?
Methylation of the GGQ motif in eRF1 enhances translation termination efficiency and is required for large ribosomal subunit biogenesis [5, 7].
Is the eRF1 methyltransferase complex conserved in humans?
Yes, the human ortholog is the HEMK2-TRMT112 complex, which methylates human eRF1 [1, 4].
What diseases are associated with eRF1 methyltransferase complex dysfunction?
Dysregulation has been linked to cancer and ribosomopathies, though direct evidence in humans is still emerging [1, 5].
How can I study the eRF1 methyltransferase complex?
Common methods include CRISPR knockout, Ribo-seq, polysome profiling, mass spectrometry, and structural biology [5, 7, 1].
What are the subunits of the yeast eRF1 methyltransferase complex?
The yeast complex consists of at least Mtq2p (catalytic) and Trm112p (activator) [2, 7].
What is the GO ID for eRF1 methyltransferase complex?
The Gene Ontology ID is GO:0035657.
Conclusion
The eRF1 methyltransferase complex (GO:0035657) is a conserved protein complex essential for methylation of the translation release factor eRF1, thereby ensuring efficient translation termination and ribosome biogenesis [5, 7]. Its components, Mtq2p and Trm112p in yeast, and HEMK2 and TRMT112 in humans, have been structurally and functionally characterized [1, 2, 4]. Dysregulation of this complex is implicated in cancer and ribosomopathies, making it a compelling target for further research [1, 5]. By leveraging CRISPR-based models and advanced omics technologies, researchers can dissect the precise roles of eRF1 methylation in health and disease. EDITGENE provides the tools and expertise to accelerate these discoveries.
References
- 1. Gao J et al.. 2020. Structural insight into HEMK2-TRMT112-mediated glutamine methylation.. Biochem J 477(19):3833-3838 PMID: 32969463
- 2. Heurgué-Hamard V et al.. 2006. The zinc finger protein Ynr046w is plurifunctional and a component of the eRF1 methyltransferase in yeast.. J Biol Chem 281(47):36140-8 PMID: 17008308
- 3. Bourgeois G et al.. 2017. Trm112, a Protein Activator of Methyltransferases Modifying Actors of the Eukaryotic Translational Apparatus.. Biomolecules 7(1) PMID: 28134793
- 4. Li W et al.. 2019. Structural insight into human N6amt1-Trm112 complex functioning as a protein methyltransferase.. Cell Discov 5:51 PMID: 31636962
- 5. Lacoux C et al.. 2020. The catalytic activity of the translation termination factor methyltransferase Mtq2-Trm112 complex is required for large ribosomal subunit biogenesis.. Nucleic Acids Res 48(21):12310-12325 PMID: 33166396
- 6. Létoquart J et al.. 2015. Insights into molecular plasticity in protein complexes from Trm9-Trm112 tRNA modifying enzyme crystal structure.. Nucleic Acids Res 43(22):10989-1002 PMID: 26438534
- 7. Heurgué-Hamard V et al.. 2005. The glutamine residue of the conserved GGQ motif in Saccharomyces cerevisiae release factor eRF1 is methylated by the product of the YDR140w gene.. J Biol Chem 280(4):2439-45 PMID: 15509572
- 8. Mazauric MH et al.. 2010. Trm112p is a 15-kDa zinc finger protein essential for the activity of two tRNA and one protein methyltransferases in yeast.. J Biol Chem 285(24):18505-15 PMID: 20400505
