GO:0004820 glycine-tRNA ligase activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0004820 (glycine-tRNA ligase activity) is the molecular function that attaches glycine to its cognate tRNA, a critical step in protein synthesis.
• The enzyme, glycyl-tRNA synthetase (GARS1), is a class II aminoacyl-tRNA synthetase that charges tRNA(Gly) with glycine using ATP.
• Mutations in GARS1 cause Charcot-Marie-Tooth disease type 2D and distal hereditary motor neuropathy type V, highlighting its role in peripheral neuropathy.
• The integrated stress response and tRNA overexpression can modulate neuropathy phenotypes caused by GARS1 mutations, offering therapeutic insights.
• SIRT2 knockdown rescues GARS-induced neuropathy in models, linking glycine-tRNA ligase activity to cellular stress pathways.
• Studying GO:0004820 requires tools like CRISPR knockout, point mutation, and overexpression models to dissect its role in translation and disease.
Description
Glycine-tRNA ligase activity (GO:0004820) is a fundamental molecular function in protein synthesis, responsible for attaching the amino acid glycine to its corresponding transfer RNA (tRNA) molecule. This reaction, catalyzed by glycyl-tRNA synthetase (GARS1 in humans), ensures that glycine is accurately incorporated into nascent polypeptides during translation. The enzyme belongs to the class II aminoacyl-tRNA synthetases and is essential for maintaining translational fidelity. Researchers study this activity to understand basic translation mechanisms and its implications in human diseases, particularly peripheral neuropathies. Mutations in GARS1 are linked to Charcot-Marie-Tooth disease type 2D and distal hereditary motor neuropathy type V, making it a target for therapeutic development. Recent studies have shown that the integrated stress response and tRNA overexpression can influence disease severity, providing potential avenues for intervention. Additionally, SIRT2 knockdown has been found to rescue GARS-induced neuropathy in experimental models, further underscoring the importance of this pathway. Understanding glycine-tRNA ligase activity is therefore crucial for both fundamental biology and clinical translation.
glycine-tRNA ligase activity At A Glance
| GO ID | GO:0004820 |
|---|---|
| GO term | glycine-tRNA ligase activity |
| Ontology | molecular_function |
| Synonym | glycyl-tRNA synthetase activity |
| Major function | Catalyzes the attachment of glycine to tRNA(Gly) for protein synthesis |
| Reaction | ATP + glycine + tRNA(Gly) = AMP + diphosphate + glycyl-tRNA(Gly) |
| Enzyme class | Class II aminoacyl-tRNA synthetase |
| Human gene | GARS1 |
| Associated disease | Charcot-Marie-Tooth disease type 2D, distal hereditary motor neuropathy type V |
What Is GO:0004820?
Glycine-tRNA ligase activity (GO:0004820) is defined as the catalysis of the reaction: ATP + glycine + tRNA(Gly) = AMP + diphosphate + glycyl-tRNA(Gly). This activity ensures the covalent attachment of glycine to its specific tRNA, a prerequisite for accurate protein synthesis.
Why Is glycine-tRNA ligase activity Important in Cell Biology?
Glycine-tRNA ligase activity is essential for translating the genetic code into functional proteins, as it ensures the correct incorporation of glycine into polypeptides. Beyond its housekeeping role, mutations in the enzyme cause inherited peripheral neuropathies, and emerging evidence links its dysfunction to cellular stress responses and potential therapeutic targets.
• Essential for protein synthesis and translational fidelity.
• Mutations cause Charcot-Marie-Tooth disease type 2D and distal hereditary motor neuropathy type V.
• The integrated stress response contributes to neuropathy caused by tRNA synthetase mutations.
• tRNA overexpression can rescue peripheral neuropathy in models.
• SIRT2 knockdown rescues GARS-induced neuropathy, suggesting a role in cellular stress.
• Provides a model for studying aminoacyl-tRNA synthetase-related diseases.
• Potential target for therapeutic intervention in peripheral neuropathies.
• Important for understanding basic mechanisms of translation.
What Happens During glycine-tRNA ligase activity?
Substrate recognition and binding
In simple terms: The enzyme first grabs the amino acid glycine and the energy molecule ATP.
Glycyl-tRNA synthetase (GARS1) specifically binds glycine and ATP in its active site, forming a glycyl-adenylate intermediate. This step ensures that only glycine is selected for charging tRNA(Gly).
tRNA charging and proofreading
In simple terms: The enzyme then attaches glycine to its matching tRNA, like a key fitting a lock.
The activated glycine is transferred to the 3' end of tRNA(Gly), forming glycyl-tRNA(Gly). The enzyme possesses proofreading activity to prevent mischarging with similar amino acids, maintaining translational accuracy.
Role in translation
In simple terms: The charged tRNA delivers glycine to the ribosome to build proteins.
Glycyl-tRNA(Gly) is delivered to the ribosome, where it pairs with glycine codons on mRNA, ensuring the correct amino acid is added to the growing polypeptide chain.
Key Genes Involved in GO:0004820 glycine-tRNA ligase activity
The following genes and proteins are directly involved in glycine-tRNA ligase activity or its regulation.
| Gene | Major Role | Research Relevance |
|---|---|---|
| GARS1 | Encodes glycyl-tRNA synthetase; catalyzes glycine-tRNA charging | Mutations cause Charcot-Marie-Tooth disease type 2D and distal hereditary motor neuropathy type V |
| SIRT2 | Deacetylase that modulates GARS-induced neuropathy | Knockdown rescues GARS-induced neuropathy in models |
| ATF4 | Transcription factor in integrated stress response | Mediates stress response in tRNA synthetase-associated neuropathy |
| EIF2AK1 | Heme-regulated inhibitor kinase | Phosphorylates eIF2α in integrated stress response |
| EIF2AK2 | Protein kinase R | Phosphorylates eIF2α in integrated stress response |
| EIF2AK3 | PERK kinase | Phosphorylates eIF2α in integrated stress response |
| EIF2AK4 | GCN2 kinase | Phosphorylates eIF2α in integrated stress response |
| AARS1 | Alanyl-tRNA synthetase | Maintains proofreading under oxidative stress |
| YARS1 | Tyrosyl-tRNA synthetase | Mutations cause peripheral neuropathy |
| GARS | Glycyl-tRNA synthetase (non-human orthologs) | Model for studying tRNA synthetase diseases |
| tRNA-Gly | Transfer RNA for glycine | Overexpression rescues neuropathy in models |
| GCN2 | Kinase in amino acid starvation response | Activates integrated stress response |
| PERK | ER stress kinase | Activates integrated stress response |
| HRI | Heme-regulated inhibitor | Activates integrated stress response |
| PKR | Double-stranded RNA-activated kinase | Activates integrated stress response |
How Is glycine-tRNA ligase activity Regulated?
Glycine-tRNA ligase activity is regulated at multiple levels. The integrated stress response, mediated by kinases such as GCN2, PERK, HRI, and PKR, can be activated by tRNA synthetase mutations, leading to eIF2α phosphorylation and altered translation. Additionally, SIRT2 deacetylase activity modulates GARS-induced neuropathy, and its knockdown rescues the phenotype. tRNA availability also regulates the enzyme's function, as overexpression of tRNA(Gly) can rescue neuropathy in models.
glycine-tRNA ligase activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| GARS1 | Charcot-Marie-Tooth disease type 2D | Knock-in mouse with GARS1 mutation |
| GARS1 | Distal hereditary motor neuropathy type V | Patient-derived iPSCs |
| GARS1 | Peripheral neuropathy with integrated stress response | Transgenic mouse overexpressing tRNA(Gly) |
| SIRT2 | Modifier of GARS-induced neuropathy | SIRT2 knockout mouse |
| AARS1 | Translational fidelity under oxidative stress | Bacterial knockout models |
Charcot-Marie-Tooth disease and distal hereditary motor neuropathy
Mutations in GARS1 cause Charcot-Marie-Tooth disease type 2D and distal hereditary motor neuropathy type V, characterized by progressive peripheral nerve degeneration. The integrated stress response contributes to the neuropathy phenotype, and tRNA overexpression or SIRT2 knockdown can rescue it in models.
Integrated stress response in neuropathy
tRNA synthetase mutations, including those in GARS1, activate the integrated stress response through eIF2α kinases, leading to altered translation and neuronal dysfunction. This pathway represents a potential therapeutic target.
From glycine-tRNA ligase activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| What is the effect of GARS1 knockout on translation? | CRISPR knockout cell lines |
| How do point mutations in GARS1 cause neuropathy? | Knock-in mouse models |
| Can tRNA overexpression rescue neuropathy? | Transgenic mouse overexpressing tRNA(Gly) |
| Does SIRT2 knockdown rescue GARS-induced neuropathy? | SIRT2 knockout mouse |
| How does oxidative stress affect proofreading? | Bacterial alanyl-tRNA synthetase mutants |
| What is the role of integrated stress response? | eIF2α kinase knockout models |
How to Study the glycine-tRNA ligase activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Ribo-seq | Translation efficiency and ribosome occupancy | Assessing impact of GARS1 mutations on translation |
| RNA-seq | tRNA and mRNA expression levels | Quantifying tRNA overexpression rescue |
| Proteomics | Protein abundance and modifications | Identifying SIRT2 targets |
| Fluorescence microscopy | Protein localization and axonal transport | Studying GARS1 trafficking |
| Aminoacylation assay | Enzyme activity | Measuring glycine-tRNA charging |
| Western blot | Protein expression and phosphorylation | Detecting eIF2α phosphorylation |
| CRISPR screening | Gene essentiality and modifiers | Identifying rescue pathways |
Ribo-seq and RNA-seq
Ribosome profiling (Ribo-seq) can measure translation efficiency and codon occupancy at glycine codons, while RNA-seq assesses tRNA expression levels. These methods help quantify the impact of GARS1 mutations on global translation.
Proteomics
Mass spectrometry-based proteomics can identify proteins with altered glycine incorporation or detect post-translational modifications in neuropathy models.
Imaging
Fluorescence microscopy can visualize tRNA localization and axonal transport defects in neurons expressing mutant GARS1.
Biochemical assays
In vitro aminoacylation assays measure glycine-tRNA ligase activity directly, using radioactive glycine and tRNA(Gly).
How CRISPR Can Be Used to Study GO:0004820 glycine-tRNA ligase activity
Knockout
CRISPR knockout of GARS1 in cell lines or animal models can reveal its essential role in translation and viability. Conditional knockouts allow tissue-specific studies of neuropathy.
Point Mutation
Introducing patient-specific GARS1 mutations (e.g., GARS1 p.Gly240Arg) via CRISPR knock-in recapitulates neuropathy phenotypes in mice, enabling mechanistic studies.
Knock-in
Knock-in of tagged GARS1 (e.g., GFP) allows real-time imaging of enzyme localization and dynamics in neurons.
Overexpression
CRISPR activation or transgenic overexpression of tRNA(Gly) can rescue neuropathy phenotypes, providing a therapeutic strategy.
How EDITGENE Supports glycine-tRNA ligase activity Research
Researchers studying glycine-tRNA ligase activity-related genes often need to determine whether a candidate gene is causally involved in translation or neuropathy. EDITGENE provides comprehensive CRISPR services to generate precisely engineered cell and animal models, accelerating functional studies and therapeutic development.
Contact EDITGENE today to design your custom CRISPR model for glycine-tRNA ligase activity research.
Frequently Asked Questions About glycine-tRNA ligase activity
What is glycine-tRNA ligase activity?
Glycine-tRNA ligase activity (GO:0004820) is the molecular function that attaches glycine to tRNA(Gly) using ATP, a key step in protein synthesis.
What genes are involved in glycine-tRNA ligase activity?
The primary gene is GARS1, which encodes glycyl-tRNA synthetase. Other genes like SIRT2 and eIF2α kinases modulate its function.
What diseases are associated with glycine-tRNA ligase activity?
Mutations in GARS1 cause Charcot-Marie-Tooth disease type 2D and distal hereditary motor neuropathy type V.
How is glycine-tRNA ligase activity regulated?
It is regulated by the integrated stress response, SIRT2 deacetylation, and tRNA availability.
What is the reaction catalyzed by glycine-tRNA ligase?
ATP + glycine + tRNA(Gly) = AMP + diphosphate + glycyl-tRNA(Gly).
Can tRNA overexpression rescue neuropathy caused by GARS1 mutations?
Yes, studies in mouse models show that tRNA(Gly) overexpression rescues peripheral neuropathy.
What is the role of SIRT2 in GARS-induced neuropathy?
SIRT2 knockdown rescues GARS-induced neuropathy, suggesting a neuroprotective effect.
How can I study glycine-tRNA ligase activity in the lab?
Common methods include aminoacylation assays, Ribo-seq, RNA-seq, and CRISPR knockout models.
What CRISPR models are available for GARS1 research?
Knockout, point mutation knock-in, tagged knock-in, and overexpression models can be generated.
Why is glycine-tRNA ligase activity important for translational fidelity?
It ensures that glycine is correctly paired with its tRNA, preventing misincorporation of amino acids into proteins.
Conclusion
Glycine-tRNA ligase activity (GO:0004820) is a cornerstone of protein synthesis, and its dysfunction leads to severe peripheral neuropathies. Understanding its mechanism, regulation, and disease connections is vital for developing targeted therapies. EDITGENE provides the tools to dissect this pathway with precision.
References
- 1. Spaulding EL et al.. 2021. The integrated stress response contributes to tRNA synthetase-associated peripheral neuropathy.. Science 373(6559):1156-1161 PMID: 34516839
- 2. Adam MP et al.. 1993. GARS1-Associated Axonal Neuropathy.. PMID: 20301420
- 3. Zuko A et al.. 2021. tRNA overexpression rescues peripheral neuropathy caused by mutations in tRNA synthetase.. Science 373(6559):1161-1166 PMID: 34516840
- 6. Zhao Y et al.. 2021. SIRT2-knockdown rescues GARS-induced Charcot-Marie-Tooth neuropathy.. Aging Cell 20(6):e13391 PMID: 34053152
- 7. Freist W et al.. 1996. Glycyl-tRNA synthetase.. Biol Chem Hoppe Seyler 377(6):343-56 PMID: 8839980
- 8. Kavoor A et al.. 2022. Escherichia coli alanyl-tRNA synthetase maintains proofreading activity and translational accuracy under oxidative stress.. J Biol Chem 298(3):101601 PMID: 35065077
