GO:0035242 protein-arginine omega-N asymmetric methyltransferase activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0035242 describes the catalytic activity that adds a second methyl group to a monomethylated peptidyl-arginine on the same terminal (omega) nitrogen, producing asymmetric dimethylarginine (ADMA) residues.
• This activity is also known as type I protein arginine methyltransferase (PRMT) activity and is carried out by enzymes such as PRMT1, PRMT2, PRMT3, PRMT4/CARM1, PRMT6, and PRMT8.
• PRMT1 is the predominant type I enzyme in mammalian cells, responsible for the majority of asymmetric arginine methylation.
• Type I PRMTs use S-adenosyl-L-methionine (SAM) as the methyl donor and generate asymmetric N(omega),N(omega)-dimethylarginine, which is distinct from the symmetric dimethylarginine produced by type II enzymes.
• Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of nitric oxide synthases, linking this activity to cardiovascular and endothelial biology.
• Dysregulation of type I PRMT activity is implicated in cancer, including acute leukemia, making it a target for degrader and inhibitor development.
Description
Protein-arginine omega-N asymmetric methyltransferase activity (GO:0035242) is a molecular function that catalyzes the transfer of a second methyl group to a monomethylated arginine residue on a protein substrate, specifically on the same terminal nitrogen that was previously methylated, yielding asymmetric N(omega),N(omega)-dimethylarginine. This activity is characteristic of type I protein arginine methyltransferases (PRMTs), a family of enzymes that post-translationally modify arginine residues in histones and other proteins. The reaction uses S-adenosyl-L-methionine (SAM) as the methyl donor and is essential for diverse cellular processes, including transcriptional regulation, RNA processing, and signal transduction. Researchers study this activity to understand how asymmetric arginine methylation controls protein function and to develop therapeutics targeting PRMTs in diseases such as cancer and cardiovascular disorders.
protein-arginine omega-N asymmetric methyltransferase activity At A Glance
| GO ID | GO:0035242 |
|---|---|
| GO term | protein-arginine omega-N asymmetric methyltransferase activity |
| Ontology | molecular_function |
| Synonym | type I PRMT activity; protein arginine omega-N asymmetric methylase activity; S-adenosyl-L-methionine:[protein]-L-arginine N-methyltransferase ([protein]-Nomega,Nomega-dimethyl-L-arginine-forming) |
| Major function | Catalyzes the formation of asymmetric dimethylarginine (ADMA) on protein substrates, typically histones and RNA-binding proteins. |
| Enzyme family | Type I protein arginine methyltransferases (PRMTs), including PRMT1, PRMT2, PRMT3, PRMT4/CARM1, PRMT6, and PRMT8. |
| Cofactor | S-adenosyl-L-methionine (SAM) serves as the methyl donor. |
| Substrate specificity | Acts on monomethylated arginine residues within glycine-arginine-rich (GAR) motifs or other contexts. |
| End product | Asymmetric N(omega),N(omega)-dimethylarginine (ADMA) on proteins; free ADMA can inhibit nitric oxide synthases. |
What Is GO:0035242?
According to the Gene Ontology, GO:0035242 is defined as the catalysis of the addition of a second methyl group to a methylated peptidyl-arginine. The methylation occurs on the same terminal nitrogen (omega nitrogen) that was previously methylated, resulting in asymmetrical peptidyl-N(omega),N(omega)-dimethylated arginine residues. In simpler terms, it is the enzymatic step that converts a monomethylated arginine into an asymmetric dimethylarginine (ADMA) on a protein, using SAM as the methyl donor.
Why Is protein-arginine omega-N asymmetric methyltransferase activity Important in Cell Biology?
GO:0035242 is critical because asymmetric arginine methylation is a major post-translational modification that regulates protein-protein interactions, nucleic acid binding, and enzymatic activity. It influences chromatin remodeling, transcription, mRNA splicing, and DNA repair, and its dysregulation is linked to cancer, cardiovascular disease, and neurological disorders. Understanding this activity provides mechanistic insight into disease and supports the development of PRMT inhibitors and degraders as therapeutic agents.
• Regulates histone methylation marks that control gene expression and chromatin structure.
• Modulates RNA-binding protein function and mRNA splicing.
• Produces asymmetric dimethylarginine (ADMA), an endogenous nitric oxide synthase inhibitor linked to endothelial dysfunction.
• PRMT1 is the predominant type I enzyme in mammalian cells and accounts for most asymmetric arginine methylation.
• Type I PRMT activity is implicated in acute leukemia and other cancers, driving interest in PRMT degraders.
• Provides a mechanism for signal transduction and protein stability regulation.
• Serves as a biomarker for disease progression and a target for small-molecule inhibitors.
• Distinguishes type I from type II and type III PRMT activities, which produce symmetric dimethylarginine or monomethylarginine, respectively.
What Happens During protein-arginine omega-N asymmetric methyltransferase activity?
Substrate recognition and binding
In simple terms: The enzyme finds and grabs onto a target protein that already has a single methyl group on an arginine.
Type I PRMTs recognize substrate proteins through specific motifs, often glycine-arginine-rich (GAR) regions. For example, PRMT1 binds histone H4 and other substrates, positioning the monomethylated arginine for further methylation. PRMT6 displays unique substrate specificity, preferring certain arginine residues in the context of specific sequences.
Methyl group transfer from SAM
In simple terms: The enzyme takes a methyl group from SAM and attaches it to the already-methylated arginine.
The catalytic mechanism involves the transfer of a methyl group from S-adenosyl-L-methionine (SAM) to the omega nitrogen of the monomethylated arginine. This second methylation step converts monomethylarginine to asymmetric dimethylarginine (ADMA). Kinetic analyses of PRMT2 have shown that it can form both monomethyl- and asymmetric dimethyl-arginine on histone H4, confirming the two-step nature of the reaction.
Formation of asymmetric dimethylarginine
In simple terms: The final product is a protein with two methyl groups on the same nitrogen, called asymmetric dimethylarginine.
The addition of the second methyl group occurs on the same terminal nitrogen that was previously methylated, resulting in an asymmetric arrangement. This distinguishes type I PRMTs from type II enzymes, which place methyl groups on different nitrogens to form symmetric dimethylarginine. The asymmetric dimethylarginine mark can alter protein interactions and function.
Product release and downstream effects
In simple terms: After the methyl groups are added, the modified protein is released and can go on to do its job in the cell.
Once asymmetric dimethylarginine is formed, the modified protein may participate in chromatin remodeling, transcriptional regulation, or RNA processing. Free asymmetric dimethylarginine (ADMA) can also be generated by proteolysis and acts as an endogenous inhibitor of nitric oxide synthases, linking this activity to vascular biology.
Key Genes Involved in GO:0035242 protein-arginine omega-N asymmetric methyltransferase activity
The following genes encode protein arginine methyltransferases and related proteins that carry out or regulate GO:0035242 activity.
| Gene | Major Role | Research Relevance |
|---|---|---|
| PRMT1 | Predominant type I PRMT; catalyzes asymmetric dimethylation of histones and other proteins | Knockout studies show loss of most asymmetric arginine methylation; linked to cancer and cardiovascular disease |
| PRMT2 | Type I enzyme with kinetic preference for forming monomethyl- and asymmetric dimethyl-arginine on histone H4 | Kinetic analyses reveal substrate specificity and reaction mechanism |
| PRMT3 | Type I enzyme; targets ribosomal protein S2 and other substrates | Degrader development for acute leukemia; potential therapeutic target |
| PRMT4 (CARM1) | Type I enzyme; methylates histone H3 and transcriptional coactivators | Implicated in hormone-dependent cancers and transcriptional regulation |
| PRMT6 | Type I enzyme with unique nuclear substrate specificity | Nuclear enzyme; potential role in DNA repair and transcription |
| PRMT8 | Type I enzyme; primarily expressed in brain | Neuronal function and development |
| PRMT5 | Type II enzyme (symmetric dimethylation) | Contrasts with type I; useful for comparative studies |
| PRMT7 | Type III enzyme forming monomethylarginine | Distinct activity; helps define type I specificity |
| PRMT9 | Type II enzyme | Less studied; potential role in RNA processing |
| CARM1 | Alternative name for PRMT4 | Transcriptional coactivator regulation |
| HNRNPA1 | Substrate of type I PRMTs; involved in RNA processing | Model substrate for studying asymmetric methylation |
| H4 | Histone substrate for PRMT1 and PRMT2 | Key readout for type I activity in chromatin |
| H3 | Histone substrate for CARM1/PRMT4 | Epigenetic mark linked to gene activation |
| RPS2 | Ribosomal protein substrate for PRMT3 | Ribosome biogenesis and leukemia |
| NOS3 | Target of ADMA inhibition | Endothelial function and cardiovascular disease |
| DDAH1 | Degrades ADMA | Regulates ADMA levels and NO signaling |
| ILF3 | RNA-binding protein substrate | mRNA stability and translation |
How Is protein-arginine omega-N asymmetric methyltransferase activity Regulated?
The activity of type I PRMTs is regulated at multiple levels. Expression levels of PRMT1, PRMT3, and other enzymes are controlled by transcription factors and microRNAs. Post-translational modifications, such as phosphorylation and ubiquitination, can modulate enzyme stability and activity. Additionally, the availability of SAM and the presence of endogenous inhibitors like ADMA can influence methyltransferase activity. PRMT3 degradation via targeted degraders has been shown to reduce asymmetric methylation and inhibit leukemia cell growth, highlighting the therapeutic potential of regulating this activity.
protein-arginine omega-N asymmetric methyltransferase activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| PRMT1 | Breast cancer, leukemia | Knockout and overexpression in cancer cell lines; xenograft models |
| PRMT3 | Acute leukemia | Degrader treatment in leukemia cell lines; CRISPR knockout |
| PRMT4 (CARM1) | Hormone-dependent cancers | Point mutation of catalytic residue; inhibitor studies |
| DDAH1 | Cardiovascular disease | Knockout mice; endothelial cell models |
| PRMT8 | Neurological disorders | Knockout mice; neuronal cultures |
Cancer
Dysregulation of type I PRMT activity is observed in multiple cancers. PRMT1 is overexpressed in breast, prostate, and lung cancers, where it promotes cell proliferation and survival. PRMT3 degraders have shown efficacy in acute leukemia models, reducing asymmetric arginine methylation and inducing apoptosis. PRMT4/CARM1 is implicated in hormone-dependent cancers and is a target for inhibitor development.
Cardiovascular disease
Asymmetric dimethylarginine (ADMA), the product of GO:0035242 activity, is an endogenous inhibitor of nitric oxide synthases. Elevated ADMA levels are associated with endothelial dysfunction, hypertension, and atherosclerosis. The enzyme DDAH1 degrades ADMA, and its dysregulation contributes to cardiovascular pathology.
Neurological disorders
PRMT8 is predominantly expressed in the brain, and its asymmetric methylation activity may influence neuronal development and function. Altered arginine methylation has been linked to neurodegenerative conditions, although the precise mechanisms remain under investigation.
From protein-arginine omega-N asymmetric methyltransferase activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of PRMT1 reduce global asymmetric dimethylation? | PRMT1 knockout cell lines (e.g., HEK293, MCF7) |
| Can a point mutation in the catalytic domain abolish type I activity? | CRISPR knock-in of catalytically dead PRMT1 (e.g., VLD to AAA) |
| Does PRMT3 degradation affect leukemia cell viability? | PRMT3 degrader treatment in AML cell lines |
| What is the substrate specificity of PRMT6? | Overexpression of tagged PRMT6 followed by mass spectrometry |
| How does asymmetric methylation of histone H4 affect chromatin? | Knock-in of H4 arginine mutants; ChIP-seq |
| Does ADMA accumulation impair endothelial function? | DDAH1 knockout mice; measurement of NO production |
How to Study the protein-arginine omega-N asymmetric methyltransferase activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| In vitro methyltransferase assay | Enzymatic activity using radiolabeled SAM | Kinetic characterization of PRMTs |
| Western blot with ADMA-specific antibody | Levels of asymmetric dimethylarginine on proteins | Detection of global or site-specific methylation |
| Mass spectrometry | Identification of methylated arginine residues | Mapping modification sites on substrates |
| CRISPR knockout | Loss-of-function phenotype | Determining gene essentiality |
| CRISPR knock-in | Introduction of point mutations or tags | Structure-function studies |
| PROTAC degrader | Induced degradation of PRMTs | Therapeutic target validation |
| ChIP-seq | Chromatin occupancy of PRMTs or histone marks | Epigenomic profiling |
| RNA-seq | Transcriptional changes upon PRMT modulation | Pathway analysis |
Measuring methyltransferase activity
In vitro methyltransferase assays using recombinant PRMTs and substrate peptides or proteins, with tritiated SAM or fluorescent SAM analogs, are standard for quantifying GO:0035242 activity. Kinetic analyses can determine Km and Vmax for substrates and cofactors.
Detecting asymmetric dimethylarginine
Site-specific antibodies against asymmetric dimethylarginine (ADMA) are used in Western blotting and immunofluorescence to detect the modification on proteins. Mass spectrometry-based proteomics can identify and quantify asymmetric dimethylation sites on a global scale.
Genetic manipulation
CRISPR/Cas9 knockout, knock-in, and point mutation of PRMT genes allow functional studies. Overexpression of wild-type or mutant PRMTs helps dissect domain functions and substrate specificity.
Pharmacological inhibition and degradation
Small-molecule inhibitors and PROTAC degraders targeting type I PRMTs are used to assess the consequences of reduced asymmetric methylation in cells and animal models.
How CRISPR Can Be Used to Study GO:0035242 protein-arginine omega-N asymmetric methyltransferase activity
Knockout
CRISPR/Cas9-mediated knockout of PRMT genes (e.g., PRMT1, PRMT3) is used to eliminate enzyme expression and assess loss of asymmetric arginine methylation and downstream phenotypes. For example, PRMT1 knockout reduces global ADMA levels and affects cell proliferation.
Point Mutation
Introducing catalytic-dead mutations (e.g., in the SAM-binding motif) via CRISPR knock-in allows separation of enzymatic activity from scaffolding functions. Such mutants help confirm that observed phenotypes are due to methyltransferase activity.
Knock-in
Knock-in of epitope tags (e.g., FLAG, HA) or fluorescent proteins at endogenous PRMT loci enables visualization and immunoprecipitation of the enzyme under native regulation. This is useful for studying localization and interactomes.
Overexpression
CRISPR activation (CRISPRa) or lentiviral overexpression of wild-type or mutant PRMTs is used to study gain-of-function effects, substrate specificity, and cellular transformation.
How EDITGENE Supports protein-arginine omega-N asymmetric methyltransferase activity Research
Researchers studying protein-arginine omega-N asymmetric methyltransferase activity-related genes often need to determine whether a candidate gene is causally involved in a specific phenotype, such as cancer cell growth or endothelial function. EDITGENE provides comprehensive CRISPR-based services to enable such investigations.
Contact EDITGENE today to design your custom CRISPR model for protein-arginine omega-N asymmetric methyltransferase activity research.
Frequently Asked Questions About protein-arginine omega-N asymmetric methyltransferase activity
What is protein-arginine omega-N asymmetric methyltransferase activity?
It is the enzymatic activity that adds a second methyl group to a monomethylated arginine on a protein, forming asymmetric dimethylarginine (ADMA). This activity is classified as GO:0035242 and is carried out by type I PRMTs.
What genes are involved in protein-arginine omega-N asymmetric methyltransferase activity?
The main genes are PRMT1, PRMT2, PRMT3, PRMT4/CARM1, PRMT6, and PRMT8, which encode type I enzymes that catalyze asymmetric dimethylation.
What is the difference between type I and type II PRMTs?
Type I PRMTs (GO:0035242) produce asymmetric dimethylarginine, while type II PRMTs produce symmetric dimethylarginine. Type III enzymes form monomethylarginine only.
Which PRMT is the predominant type I enzyme in mammalian cells?
PRMT1 is the predominant type I enzyme, responsible for the majority of asymmetric arginine methylation in mammalian cells.
What is the role of asymmetric dimethylarginine (ADMA) in disease?
ADMA is an endogenous inhibitor of nitric oxide synthases. Elevated ADMA levels are linked to cardiovascular diseases such as hypertension and atherosclerosis.
How is protein-arginine omega-N asymmetric methyltransferase activity measured?
It is measured using in vitro methyltransferase assays with radiolabeled SAM, or by detecting ADMA with specific antibodies or mass spectrometry.
Can CRISPR be used to study PRMT function?
Yes, CRISPR knockout, knock-in, and point mutation models are widely used to study PRMT function and asymmetric methylation.
What diseases are associated with type I PRMT dysregulation?
Type I PRMTs are implicated in cancer (e.g., leukemia, breast cancer) and cardiovascular disease.
What is the substrate specificity of PRMT6?
PRMT6 is a nuclear type I enzyme with unique substrate specificity, methylating arginine residues in specific sequence contexts.
How does PRMT3 contribute to leukemia?
PRMT3 methylates ribosomal protein S2 and supports leukemia cell growth; its degradation reduces asymmetric methylation and induces apoptosis.
Conclusion
GO:0035242, protein-arginine omega-N asymmetric methyltransferase activity, is a fundamental molecular function that generates asymmetric dimethylarginine on proteins. It is executed by type I PRMTs such as PRMT1, PRMT3, and PRMT6, and plays critical roles in chromatin regulation, RNA processing, and signal transduction. Dysregulation of this activity is linked to cancer and cardiovascular disease, making it a promising therapeutic target. Continued research using CRISPR models and advanced proteomics will further illuminate its mechanisms and disease relevance.
References
- 1. Frankel A et al.. 2002. The novel human protein arginine N-methyltransferase PRMT6 is a nuclear enzyme displaying unique substrate specificity.. J Biol Chem 277(5):3537-43 PMID: 11724789
- 2. Zurita-Lopez CI et al.. 2012. Human protein arginine methyltransferase 7 (PRMT7) is a type III enzyme forming ω-NG-monomethylated arginine residues.. J Biol Chem 287(11):7859-70 PMID: 22241471
- 3. Lakowski TM et al.. 2010. Approaches to measuring the activities of protein arginine N-methyltransferases.. Anal Biochem 397(1):1-11 PMID: 19761747
- 4. Lakowski TM et al.. 2009. Kinetic analysis of human protein arginine N-methyltransferase 2: formation of monomethyl- and asymmetric dimethyl-arginine residues on histone H4.. Biochem J 421(2):253-61 PMID: 19405910
- 5. Takahashi Y et al.. 2011. The C. elegans PRMT-3 possesses a type III protein arginine methyltransferase activity.. J Recept Signal Transduct Res 31(2):168-72 PMID: 21385054
- 6. Zou W et al.. 2024. Discovery of PRMT3 Degrader for the Treatment of Acute Leukemia.. Adv Sci (Weinh) 11(38):e2405963 PMID: 39120042
- 7. Tang J et al.. 2000. PRMT1 is the predominant type I protein arginine methyltransferase in mammalian cells.. J Biol Chem 275(11):7723-30 PMID: 10713084
- 8. Leiper J et al.. 1999. Biological significance of endogenous methylarginines that inhibit nitric oxide synthases.. Cardiovasc Res 43(3):542-8 PMID: 10690326
