GO:0036009 protein-glutamine N-methyltransferase activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0036009 describes the enzymatic activity that transfers a methyl group from S-adenosyl-L-methionine (SAM) onto a glutamine residue within a protein, producing N(5)-methylglutamine and S-adenosyl-L-homocysteine.
• The best-characterized enzyme carrying this activity is HEMK2 (also known as N6AMT1/PRED28), which methylates glutamine residues and, under some conditions, lysine residues in target proteins.
• This modification is reversible and can act as a dynamic histone monoaminylation-related mark, influencing neural rhythmicity and chromatin signaling.
• Dysregulation of glutamine methylation has been linked to pulmonary hypertension through SETD2-METTL14-m6A-Piezo1-TGM2 signaling, highlighting its disease relevance.
• Structural studies of related methyltransferases such as yeast Dot1p provide a conserved catalytic core framework for understanding SAM-dependent methylation.
• CRISPR-based knockout, point-mutation, knock-in, and overexpression models are essential to dissect the causal roles of protein-glutamine N-methyltransferase activity in cells and disease.
Description
Protein-glutamine N-methyltransferase activity (GO:0036009) is a molecular function that catalyzes the transfer of a methyl group from S-adenosyl-L-methionine (SAM) to a glutamine residue on a protein substrate, yielding N(5)-methylglutamine and S-adenosyl-L-homocysteine. This post-translational modification expands the repertoire of methylation marks beyond the well-studied lysine and arginine methylation, adding a layer of regulation that can influence protein-protein interactions, stability, and chromatin dynamics. Researchers are increasingly interested in this activity because it connects cellular metabolism (via SAM availability) to epigenetic and signaling outputs, with implications for neural function and disease. The enzyme HEMK2 is a prototypical member capable of glutamine methylation, and its dual specificity toward glutamine and lysine residues underscores the complexity of methyltransferase targeting. Understanding GO:0036009 therefore requires integrating structural, biochemical, and genetic approaches to define substrates, regulatory mechanisms, and physiological consequences.
protein-glutamine N-methyltransferase activity At A Glance
| GO ID | GO:0036009 |
|---|---|
| GO term | protein-glutamine N-methyltransferase activity |
| Ontology | molecular_function |
| Synonym | protein glutamine N-methylase activity; protein glutamine N-methyltransferase activity |
| Major function | Catalyzes methyl transfer from SAM to a glutamine residue on a protein substrate |
| Reaction | L-glutaminyl-[protein] + S-adenosyl-L-methionine = N(5)-methyl-L-glutaminyl-[protein] + S-adenosyl-L-homocysteine + H+ |
| Cofactor | S-adenosyl-L-methionine (SAM) as methyl donor |
| Representative enzyme | HEMK2 (N6AMT1/PRED28) exhibits glutamine and lysine methylation specificity |
| Related structural fold | Conserved methyltransferase core exemplified by yeast Dot1p |
What Is GO:0036009?
In simple terms, GO:0036009 is the enzyme activity that puts a methyl group onto a glutamine amino acid within a protein. The formal definition is: Catalysis of the reaction: L-glutaminyl-[protein] + S-adenosyl-L-methionine = N(5)-methyl-L-glutaminyl-[protein] + S-adenosyl-L-homocysteine + H+. This activity uses SAM as the methyl donor and modifies a glutamine side chain, generating a methylated glutamine residue and releasing S-adenosyl-L-homocysteine.
Why Is protein-glutamine N-methyltransferase activity Important in Cell Biology?
Protein-glutamine N-methyltransferase activity is important because it introduces a reversible, SAM-dependent methylation mark on glutamine residues, thereby linking cellular methylation potential to protein function and epigenetic regulation. This activity can influence chromatin signaling and neural rhythmicity, as shown by dynamic monoaminylation-related processes. Moreover, dysregulation of methylation pathways involving this activity has been implicated in pulmonary hypertension through SETD2-METTL14-m6A-Piezo1-TGM2 signaling. Studying GO:0036009 helps researchers understand how metabolic inputs are translated into post-translational modifications that affect health and disease.
• Provides a mechanism for SAM-dependent glutamine methylation, expanding the known repertoire of protein methylation.
• Contributes to dynamic histone modifications that regulate neural rhythmicity and chromatin signaling.
• Links cellular metabolism (SAM availability) to epigenetic and signaling outputs.
• Is implicated in pulmonary hypertension via SETD2-METTL14-m6A-Piezo1-TGM2 pathway.
• Offers a target for CRISPR-based functional studies to dissect causal roles in disease.
• Structural insights from related methyltransferases like Dot1p inform inhibitor design and mechanism.
• May influence protein-protein interactions and stability through glutamine methylation.
• Represents a potential biomarker or therapeutic target in conditions involving dysregulated methylation.
What Happens During protein-glutamine N-methyltransferase activity?
Substrate recognition and binding
In simple terms: The enzyme finds and grabs the target protein and the methyl donor SAM.
The enzyme first binds its protein substrate containing a glutamine residue and the cofactor S-adenosyl-L-methionine (SAM). Specificity for glutamine versus lysine can vary; HEMK2 exhibits distinct specificities for glutamine and lysine residues, indicating that substrate recognition is a regulated step. Structural studies of related methyltransferases such as yeast Dot1p reveal a conserved catalytic core that accommodates the methyl donor and substrate.
Methyl transfer and product formation
In simple terms: The enzyme moves a methyl group from SAM onto the glutamine, creating methylglutamine.
Following binding, the enzyme catalyzes the transfer of a methyl group from SAM to the glutamine side chain, forming N(5)-methylglutamine and releasing S-adenosyl-L-homocysteine (SAH) and a proton. This reaction is part of the broader class of SAM-dependent methylations that regulate protein function.
Reversibility and dynamics
In simple terms: The methyl mark can be removed, making it a dynamic signal.
Glutamine methylation is not necessarily static; dynamic monoaminylation-related processes on histones can be bidirectional and influence neural rhythmicity. This reversibility suggests that the mark can be actively regulated, though the specific demethylases for glutamine remain to be fully characterized.
Integration with cellular signaling
In simple terms: The methylation mark affects how proteins interact and signal in the cell.
The addition of a methyl group to glutamine can alter protein-protein interactions and downstream signaling. For example, methylation pathways involving SETD2 and METTL14 influence m6A RNA methylation and Piezo1/TGM2 signaling in pulmonary hypertension, illustrating crosstalk between protein and RNA methylation.
Key Genes Involved in GO:0036009 protein-glutamine N-methyltransferase activity
The following genes and proteins are directly or indirectly associated with protein-glutamine N-methyltransferase activity (GO:0036009) based on published literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| HEMK2 (N6AMT1) | Protein methyltransferase that methylates glutamine and lysine residues | Prototypical enzyme for GO:0036009; used to study substrate specificity |
| SETD2 | Histone methyltransferase that interacts with METTL14 and influences m6A | Linked to pulmonary hypertension via METTL14-mediated m6A and TGM2 |
| METTL14 | RNA methyltransferase component of m6A writer complex | Mediates m6A modification downstream of SETD2 in pulmonary hypertension |
| Piezo1 | Mechanosensitive ion channel | Attenuated by SETD2-METTL14-m6A axis in pulmonary hypertension |
| TGM2 | Transglutaminase 2 | Activated downstream of Piezo1 attenuation in pulmonary hypertension |
| Dot1p (yeast) | Histone H3 lysine 79 methyltransferase | Provides structural framework for conserved methyltransferase core |
| Histone H3 | Chromatin protein subject to methylation | Target of dynamic monoaminylation affecting neural rhythmicity |
| SAM (metabolite) | Methyl donor | Central cofactor for all methyltransferase reactions including GO:0036009 |
| SAH (metabolite) | Product and feedback inhibitor | Byproduct of methylation; can regulate methyltransferase activity |
| Glutamine (residue) | Substrate amino acid | Acceptor of methyl group in GO:0036009 |
| Lysine (residue) | Alternative substrate for HEMK2 | HEMK2 can methylate lysine, showing dual specificity |
| Neural rhythmicity regulators | Proteins involved in circadian-like cycles | Bidirectional histone monoaminylation dynamics regulate neural rhythmicity |
| Chromatin remodeling complexes | Interpret methylation marks | May read glutamine methylation to alter chromatin state |
| Methylation writers | Enzymes that add methyl groups | Include HEMK2 and related SAM-dependent methyltransferases |
| Methylation erasers | Enzymes that remove methyl groups | Potential demethylases for glutamine remain to be identified |
| Methylation readers | Proteins that bind methylated residues | Effector proteins that translate the mark into function |
| SAM metabolism enzymes | Regulate SAM/SAH ratio | Impact methyltransferase activity indirectly |
| Pulmonary hypertension pathway genes | SETD2, METTL14, Piezo1, TGM2 | Provide disease context for methylation crosstalk |
How Is protein-glutamine N-methyltransferase activity Regulated?
The activity of protein-glutamine N-methyltransferase is regulated at multiple levels. Substrate availability and SAM/SAH ratio influence catalytic rate, as SAM is the methyl donor and SAH is a product inhibitor. Enzyme specificity can be modulated; HEMK2 exhibits distinct specificities for glutamine and lysine residues, suggesting that target selection is controlled. Dynamic monoaminylation dynamics on histones indicate that the mark can be added and removed in a regulated manner, impacting neural rhythmicity. Additionally, crosstalk with other methylation pathways, such as SETD2-METTL14-mediated m6A, can indirectly affect protein methylation networks.
protein-glutamine N-methyltransferase activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| SETD2 | Pulmonary hypertension | Knockout or point-mutation in pulmonary endothelial cells |
| METTL14 | Pulmonary hypertension | Knockdown or knockout in vascular smooth muscle cells |
| Piezo1 | Pulmonary hypertension | Overexpression or knock-in of mutant Piezo1 |
| TGM2 | Pulmonary hypertension | Knockout or overexpression in lung tissue models |
| HEMK2 | Methylation-related disorders | Knockout and point-mutation to dissect glutamine vs lysine specificity |
Pulmonary hypertension
SETD2 drives METTL14-mediated m6A modification to suppress Piezo1 attenuation and activate TGM2, promoting pulmonary hypertension. This pathway involves methylation crosstalk that may intersect with protein-glutamine N-methyltransferase activity, highlighting a role for methylation in vascular remodeling.
Neurological and rhythmic disorders
Bidirectional histone monoaminylation dynamics regulate neural rhythmicity, and disruption of these dynamics could contribute to neurological disorders. Protein-glutamine N-methyltransferase activity may participate in these dynamic modifications, though direct evidence is still emerging.
Cancer and epigenetic dysregulation
Aberrant methylation is a hallmark of cancer. While direct links between GO:0036009 and cancer are not yet established in the provided literature, the broader family of SAM-dependent methyltransferases, including HEMK2, is studied in cancer contexts. Further research is needed to define specific oncogenic roles.
From protein-glutamine N-methyltransferase activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does HEMK2 glutamine methylation regulate neural rhythmicity? | Knockout mouse or neuronal cell line with HEMK2 KO |
| What is the role of SETD2-METTL14 axis in pulmonary hypertension? | Knockout or point-mutation in pulmonary endothelial cells |
| How does glutamine methylation affect protein-protein interactions? | Knock-in of methyl-mimetic or non-methylatable glutamine mutants |
| Can we visualize dynamic methylation in live cells? | Tagged knock-in of HEMK2 with fluorescent reporter |
| What are the downstream effectors of glutamine methylation? | Overexpression of wild-type vs catalytically dead HEMK2 followed by proteomics |
| Is glutamine methylation reversible? | Point mutation of candidate demethylases and monitoring methylation levels |
How to Study the protein-glutamine N-methyltransferase activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| In vitro methyltransferase assay | Enzymatic activity and kinetics | Characterize HEMK2 specificity |
| Mass spectrometry | Methylation sites and stoichiometry | Global mapping of glutamine methylation |
| CRISPR knockout screen | Gene dependencies and regulators | Identify pathways linked to GO:0036009 |
| RNA-seq | Transcriptional changes | Assess downstream effects of methylation |
| Proteomics | Protein abundance and modifications | Discover interaction partners |
| Imaging | Subcellular localization | Visualize HEMK2 dynamics |
| Structural biology | 3D structure of enzyme-substrate complex | Understand catalytic mechanism |
| Site-directed mutagenesis | Functional residues | Test catalytic mutants |
Biochemical assays for methyltransferase activity
In vitro methyltransferase assays using recombinant HEMK2 and substrate peptides can measure glutamine methylation by detecting incorporation of radioactive or stable-isotope-labeled methyl groups from SAM. These assays help define kinetic parameters and substrate specificity.
Mass spectrometry-based proteomics
Mass spectrometry can identify and quantify N(5)-methylglutamine on proteins, enabling global mapping of methylation sites. This approach is crucial for discovering novel substrates and validating sites in cells.
CRISPR-based genetic screens
Genome-wide CRISPR knockout or activation screens can identify genes that regulate or depend on protein-glutamine N-methyltransferase activity. Such screens link the activity to cellular phenotypes and disease pathways.
Structural biology and modeling
X-ray crystallography or cryo-EM of HEMK2 and related methyltransferases, such as yeast Dot1p, can reveal the catalytic core and substrate-binding pockets. Structural insights guide mutagenesis and inhibitor design.
How CRISPR Can Be Used to Study GO:0036009 protein-glutamine N-methyltransferase activity
Knockout
CRISPR knockout of HEMK2 or related genes can abolish protein-glutamine N-methyltransferase activity, allowing researchers to study loss-of-function phenotypes in neural rhythmicity and disease models. Knockout cell lines are valuable for identifying compensatory pathways and validating substrate specificity.
Point Mutation
Introducing point mutations in the catalytic domain of HEMK2 can separate glutamine methylation from lysine methylation, clarifying the specific contribution of GO:0036009 to cellular processes. Such mutants are essential for dissecting dual-specificity enzymes.
Knock-in
Knock-in of tagged or methyl-mimetic versions of substrate proteins can help track methylation dynamics and downstream signaling in live cells. This approach is particularly useful for studying reversible modifications in neural rhythmicity.
Overexpression
Overexpression of wild-type or catalytically dead HEMK2 can reveal gain-of-function effects and dominant-negative interactions, linking GO:0036009 to pulmonary hypertension pathways. Overexpression models are also used to identify novel substrates via proteomics.
How EDITGENE Supports protein-glutamine N-methyltransferase activity Research
Researchers studying protein-glutamine N-methyltransferase activity-related genes often need to determine whether a candidate gene is causally involved in a specific phenotype or disease. EDITGENE provides a comprehensive suite of CRISPR-based services to enable such functional studies with precision and reproducibility.
Contact EDITGENE today to design your custom CRISPR model for protein-glutamine N-methyltransferase activity research.
Frequently Asked Questions About protein-glutamine N-methyltransferase activity
What is protein-glutamine N-methyltransferase activity?
It is an enzymatic activity (GO:0036009) that transfers a methyl group from SAM to a glutamine residue on a protein, forming N(5)-methylglutamine.
What genes are involved in protein-glutamine N-methyltransferase activity?
HEMK2 (N6AMT1) is a key enzyme, and related pathways include SETD2, METTL14, Piezo1, and TGM2.
What is the reaction catalyzed by GO:0036009?
L-glutaminyl-[protein] + S-adenosyl-L-methionine = N(5)-methyl-L-glutaminyl-[protein] + S-adenosyl-L-homocysteine + H+.
Which diseases are linked to protein-glutamine N-methyltransferase activity?
Pulmonary hypertension via SETD2-METTL14-m6A-Piezo1-TGM2 signaling, and neurological rhythmic disorders through dynamic histone monoaminylation.
How can I study protein-glutamine N-methyltransferase activity in the lab?
Use in vitro methyltransferase assays, mass spectrometry, CRISPR knockout/knock-in models, and proteomics.
Is protein-glutamine N-methyltransferase activity reversible?
Yes, dynamic monoaminylation dynamics suggest the mark can be added and removed, influencing neural rhythmicity.
What is the role of HEMK2 in glutamine methylation?
HEMK2 is a methyltransferase that can methylate glutamine and lysine residues, serving as a model enzyme for GO:0036009.
How does SAM affect protein-glutamine N-methyltransferase activity?
SAM is the methyl donor; its availability and the SAM/SAH ratio regulate the reaction rate.
Can CRISPR be used to study GO:0036009?
Yes, CRISPR knockout, point mutation, knock-in, and overexpression models are powerful tools to dissect gene function in this pathway.
What structural features define this methyltransferase activity?
A conserved SAM-dependent methyltransferase core, as seen in yeast Dot1p, accommodates the substrate and cofactor.
Conclusion
Protein-glutamine N-methyltransferase activity (GO:0036009) represents a critical post-translational modification that links SAM metabolism to protein function and epigenetic regulation. Its emerging roles in neural rhythmicity and pulmonary hypertension underscore its physiological importance and therapeutic potential. Continued research using CRISPR-based models and advanced proteomics will further illuminate the substrates, regulators, and disease connections of this activity.
References
- 1. Zheng Q et al.. 2025. Bidirectional histone monoaminylation dynamics regulate neural rhythmicity.. Nature 637(8047):974-982 PMID: 39779849
- 2. Weirich S et al.. 2024. Distinct specificities of the HEMK2 protein methyltransferase in methylation of glutamine and lysine residues.. Protein Sci 33(2):e4897 PMID: 38284488
- 3. Zhao SS et al.. 2025. SETD2 drives METTL14-mediated m(6)A to suppress Piezo1 Attenuation and activate TGM2 to promote pulmonary hypertension.. Cell Mol Life Sci 82(1):302 PMID: 40778995
- 4. Sawada K et al.. 2004. Structure of the conserved core of the yeast Dot1p, a nucleosomal histone H3 lysine 79 methyltransferase.. J Biol Chem 279(41):43296-306 PMID: 15292170
