GO:0048269 methionine adenosyltransferase complex: Components, Assembly and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0048269 describes the multimeric enzyme complex that synthesizes S-adenosylmethionine (AdoMet/SAM), the major methyl-group donor for methylation of DNA, RNA, proteins, phospholipids and small molecules.
• The complex is built from catalytic alpha subunits (MAT1A, MAT2A) and regulatory beta subunits (MAT2B), whose variable stoichiometry tunes enzyme activity and stability.
• MAT2A is the dominant alpha subunit in proliferating cells and is a synthetic-lethal target in MTAP-deleted cancers, where MAT2A inhibition reduces PRMT5-dependent splicing and induces DNA damage.
• MAT1A is the liver-specific alpha subunit; its loss, together with prohibitin 1, promotes primary and secondary liver cancer metastasis.
• The complex is regulated by nutrient and oncogenic signals, including mTORC1-driven SAM synthesis for m6A-dependent protein synthesis and cullin 3-mediated ubiquitylation of MAT II alpha.
• CRISPR knockout, point-mutation, knock-in and overexpression models are essential to dissect subunit-specific functions of the methionine adenosyltransferase complex in cancer and metabolic disease.
Description
The methionine adenosyltransferase complex (GO:0048269) is a multimeric enzyme assembly that catalyzes the synthesis of S-adenosylmethionine (AdoMet, also called SAM), the principal methyl-group donor used in methylation of proteins, DNA, RNA, phospholipids and other small molecules. Because SAM is the universal methyl donor, the activity of this complex sits at the intersection of methionine metabolism, epigenetic regulation and cell growth control. In mammalian cells, the complex is composed of variable numbers of catalytic alpha subunits and noncatalytic beta subunits, and the beta subunits are believed to have a regulatory function. The two principal alpha subunits are MAT1A, which is largely liver-specific, and MAT2A, which is widely expressed in proliferating cells; MAT2B is the main beta subunit. Researchers study GO:0048269 because its output, SAM, controls methylation reactions that influence gene expression, RNA processing and genome stability, and because altered complex activity is linked to cancer, liver disease and metabolic disorders. Understanding how the complex is assembled, regulated and targeted is therefore central to both basic methylome biology and therapeutic development.
methionine adenosyltransferase complex At A Glance
| GO ID | GO:0048269 |
|---|---|
| GO term | methionine adenosyltransferase complex |
| Ontology | cellular_component |
| Synonym | MAT complex |
| Major function | Catalyzes synthesis of S-adenosylmethionine (AdoMet/SAM), the major methyl-group donor for methylation of proteins, DNA, RNA, phospholipids and small molecules |
| Subunit composition | Variable numbers of catalytic alpha subunits (e.g., MAT1A, MAT2A) and noncatalytic beta subunits (e.g., MAT2B) with regulatory function |
| Key catalytic product | S-adenosylmethionine (SAM/AdoMet) |
| Representative regulators | mTORC1 signaling, cullin 3-mediated ubiquitylation, dietary folate and methionine availability |
| Disease relevance | MTAP-deleted cancers, hepatocellular carcinoma, alcohol-associated liver disease and metastasis |
What Is GO:0048269?
GO:0048269, methionine adenosyltransferase complex, is a cellular-component term describing a multimeric enzyme complex composed of variable numbers of catalytic alpha subunits and noncatalytic beta subunits. The beta subunits are believed to have a regulatory function. The enzyme complex catalyzes the synthesis of S-adenosylmethionine (AdoMet), which is the major methyl-group donor participating in the methylation of proteins, DNA, RNA, phospholipids and other small molecules.
Why Is methionine adenosyltransferase complex Important in Cell Biology?
The methionine adenosyltransferase complex is important because it produces SAM, the methyl donor required for essentially all cellular methylation reactions, including DNA methylation, histone methylation, RNA methylation and phospholipid methylation. Through SAM supply, the complex directly influences epigenetic states, mRNA splicing and translation, and genome stability, making it a central node in metabolic-epigenetic crosstalk. Its subunit composition and regulation are frequently altered in cancer and liver disease, and MAT2A has emerged as a synthetic-lethal target in MTAP-deleted tumors. Consequently, the complex is a high-value subject for both mechanistic studies and therapeutic development.
• Supplies SAM, the universal methyl donor for DNA, RNA, protein, phospholipid and small-molecule methylation.
• Controls PRMT5-dependent mRNA splicing and DNA damage responses in cancer cells.
• Links mTORC1 signaling to m6A RNA methylation and protein synthesis.
• Represents a synthetic-lethal vulnerability in MTAP-deleted cancers.
• Liver-specific MAT1A loss, together with prohibitin 1, promotes primary and secondary liver cancer metastasis.
• MAT1A and SAM metabolism are implicated in alcohol-associated liver disease.
• MAT II alpha (MAT2A) is regulated by cullin 3-mediated ubiquitylation in colorectal cancer.
• Dietary folate stabilizes MAT IIA and promotes cancer development through methionine metabolism.
• Provides a mechanistic bridge between one-carbon metabolism and epigenetic regulation.
• Offers druggable nodes (MAT2A, MAT2B) for oncology and metabolic disease.
What Happens During methionine adenosyltransferase complex?
SAM biosynthesis by the MAT complex
In simple terms: The complex takes methionine and ATP and turns them into SAM, the cell's main methyl donor.
The methionine adenosyltransferase complex catalyzes the synthesis of S-adenosylmethionine (AdoMet/SAM) from methionine and ATP. SAM is the major methyl-group donor participating in methylation of proteins, DNA, RNA, phospholipids and other small molecules. This reaction places the complex at the entry point of methyl-transfer metabolism and makes its activity rate-limiting for many methylation reactions.
Subunit-dependent catalytic and regulatory functions
In simple terms: Alpha subunits do the chemistry, while beta subunits tune how much chemistry happens.
The complex is composed of variable numbers of catalytic alpha subunits and noncatalytic beta subunits, and the beta subunits are believed to have a regulatory function. In mammals, MAT1A and MAT2A are the principal catalytic alpha subunits, while MAT2B is the main regulatory beta subunit. Different alpha/beta stoichiometries can alter enzyme activity and stability, allowing the complex to adapt SAM output to cellular demand.
Coupling to mTORC1 and m6A-dependent translation
In simple terms: Growth signals boost SAM production, which in turn helps the cell make proteins.
mTORC1 stimulates cell growth through SAM synthesis and m6A mRNA-dependent control of protein synthesis. This links nutrient and growth-factor signaling to the methionine adenosyltransferase complex and to downstream RNA methylation events that regulate translation. The complex therefore participates in a metabolic-epigenetic circuit that supports biosynthetic growth.
SAM consumption and feedback
In simple terms: When SAM is used up by methylation reactions, the complex is signaled to make more.
SAM produced by the complex is consumed by methyltransferases, including PRMT5, which uses SAM for arginine methylation of splicing factors. Reduced SAM availability following MAT2A inhibition impairs PRMT5-dependent mRNA splicing and induces DNA damage in MTAP-deleted cancer cells. These findings indicate that the complex is functionally coupled to downstream methylation demand and to genome maintenance.
Key Genes Involved in GO:0048269 methionine adenosyltransferase complex
The following genes encode subunits, regulators and downstream effectors of the methionine adenosyltransferase complex (GO:0048269) and are commonly studied in this context.
| Gene | Major Role | Research Relevance |
|---|---|---|
| MAT1A | Liver-specific catalytic alpha subunit of the MAT complex | Loss promotes primary and secondary liver cancer metastasis together with prohibitin 1; implicated in alcohol-associated liver disease |
| MAT2A | Widely expressed catalytic alpha subunit (MAT II alpha) | Synthetic-lethal target in MTAP-deleted cancers; regulates PRMT5-dependent splicing and DNA damage; ubiquitylated by cullin 3; stabilized by dietary folate |
| MAT2B | Noncatalytic regulatory beta subunit of the MAT complex | Modulates MAT2A activity and SAM synthesis; component of the MAT complex |
| PRMT5 | SAM-dependent protein arginine methyltransferase | Effector of SAM produced by the MAT complex; mediates splicing and DNA damage responses |
| RIOK1 | Kinase in the PRMT5/RIOK1 axis | Part of the MAT2A/PRMT5/RIOK1 vulnerability in MTAP-deleted cancers |
| MTAP | Methylthioadenosine phosphorylase | Deletion creates dependence on MAT2A and the MAT complex |
| PHB1 | Prohibitin 1, mitochondrial chaperone | Cooperates with MAT1A to defend against liver cancer metastasis |
| CUL3 | Cullin 3 E3 ubiquitin ligase | Targets MAT II alpha for ubiquitylation-mediated degradation in colorectal cancer |
| mTORC1 | Growth-signaling kinase complex | Stimulates SAM synthesis and m6A-dependent protein synthesis via the MAT complex |
| METTL3 | m6A RNA methyltransferase | Downstream reader/writer of SAM-dependent m6A marks |
| MAT2A (folate axis) | Folate-responsive MAT IIA stabilization | Dietary folate drives methionine metabolism to promote cancer development |
| SAM (metabolite) | Product of the MAT complex | Central methyl donor for methylation reactions |
| AdoMet (metabolite) | Alternative name for SAM | Major methyl-group donor in cells |
| MAT complex (holoenzyme) | Alpha/beta multimeric assembly | Functional unit defined by GO:0048269 |
| MAT II (isoenzyme) | MAT2A/MAT2B-containing complex | Predominant in proliferating and cancer cells |
| MAT I/III (isoenzyme) | MAT1A-containing complexes | Liver-specific forms relevant to liver disease and cancer |
How Is methionine adenosyltransferase complex Regulated?
The methionine adenosyltransferase complex is regulated at multiple levels. mTORC1 signaling stimulates SAM synthesis and m6A mRNA-dependent control of protein synthesis, linking growth signals to complex activity. Cullin 3 targets MAT II alpha for ubiquitylation-mediated degradation, providing post-translational control of MAT2A protein levels in colorectal cancer cells. Dietary folate stabilizes MAT IIA and drives methionine metabolism to promote cancer development, indicating nutrient-dependent regulation. In liver, MAT1A and prohibitin 1 cooperate to defend against primary and secondary liver cancer metastasis, and MAT1A/SAM metabolism is altered in alcohol-associated liver disease. Together, these mechanisms tune SAM output to match cellular methylation demand.
methionine adenosyltransferase complex and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| MAT2A | MTAP-deleted cancers; PRMT5-dependent splicing and DNA damage | MAT2A knockout or point-mutation in MTAP-deleted cancer cell lines |
| MAT1A | Liver cancer metastasis; alcohol-associated liver disease | Mat1a knockout mouse models and liver cancer cell lines |
| MAT2B | Regulatory subunit in MAT complex; cancer metabolism | MAT2B knockout and overexpression cell models |
| CUL3 | Colorectal cancer cell proliferation via MAT II alpha degradation | CUL3 knockout or overexpression in colorectal cancer cells |
| MTAP | Synthetic lethality with MAT2A in cancer | MTAP-deleted isogenic cancer cell pairs |
MTAP-deleted cancers and synthetic lethality
MTAP deletions in cancer create vulnerability to targeting of the MAT2A/PRMT5/RIOK1 axis. MAT2A inhibition blocks the growth of MTAP-deleted cancer cells by reducing PRMT5-dependent mRNA splicing and inducing DNA damage. MTAP deletion in oncogenesis is therefore considered a synthetic-lethality scenario that positions the methionine adenosyltransferase complex as a therapeutic target.
Liver cancer and metastasis
Hepatic prohibitin 1 and methionine adenosyltransferase alpha1 (MAT1A) defend against primary and secondary liver cancer metastasis. Loss of MAT1A and SAM metabolism is also implicated in alcohol-associated liver disease, which is a risk factor for liver cancer. These findings link the liver-specific MAT complex to tumor suppression and metastatic control.
Colorectal cancer and MAT II alpha stability
Cullin 3 targets methionine adenosyltransferase II alpha for ubiquitylation-mediated degradation and regulates colorectal cancer cell proliferation. Dietary folate drives methionine metabolism to promote cancer development by stabilizing MAT IIA, further supporting a role for the complex in colorectal and other cancers.
From methionine adenosyltransferase complex-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of MAT2A reduce SAM and impair PRMT5-dependent splicing? | MAT2A knockout cell lines with RNA-seq and splicing assays |
| Does MAT1A loss promote liver cancer metastasis? | Mat1a knockout mouse models and liver cancer cell lines |
| How does mTORC1 regulate SAM synthesis and m6A-dependent translation? | mTORC1 perturbation with SAM and m6A profiling |
| Does cullin 3 control MAT II alpha stability? | CUL3 knockout or overexpression with ubiquitylation assays |
| Does dietary folate stabilize MAT IIA in cancer? | Folate-modulated cell culture and xenograft models |
| Can MAT2A inhibition selectively kill MTAP-deleted cells? | Isogenic MTAP-deleted and wild-type cancer cell pairs |
How to Study the methionine adenosyltransferase complex Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Metabolomics (SAM/AdoMet) | Intracellular SAM levels | Assessing MAT complex activity and target engagement |
| RNA-seq / splicing assays | mRNA splicing changes | Detecting PRMT5-dependent splicing defects after MAT2A inhibition |
| MeRIP-seq / m6A profiling | m6A RNA methylation | Linking mTORC1-SAM axis to translation control |
| Proteomics / ubiquitylation assays | MAT2A protein stability | Studying cullin 3-mediated degradation |
| Cell proliferation assays | Growth and viability | Testing synthetic lethality in MTAP-deleted cells |
| Mouse metastasis models | Tumor metastasis | Evaluating MAT1A and prohibitin 1 function in liver cancer |
| Folate modulation experiments | MAT IIA stabilization | Testing dietary folate effects on methionine metabolism |
| Immunoblotting | Subunit protein levels | Confirming knockout or overexpression of MAT subunits |
Metabolomics and SAM quantification
Because the methionine adenosyltransferase complex produces SAM, metabolomic profiling of SAM and related metabolites is a direct readout of complex activity. Such measurements are used to confirm target engagement after MAT2A inhibition and to link complex function to methylation capacity.
RNA-seq and splicing analysis
MAT2A inhibition reduces PRMT5-dependent mRNA splicing, so RNA-seq and splicing-sensitive assays are used to detect intron retention and altered splice isoform ratios in MTAP-deleted cancer cells. These methods connect the complex to post-transcriptional gene regulation.
m6A RNA methylation profiling
mTORC1 stimulates SAM synthesis and m6A mRNA-dependent control of protein synthesis, making m6A profiling (e.g., MeRIP-seq) a key method to study downstream effects of the complex. This approach links the complex to translation control.
Proteomics and ubiquitylation assays
Cullin 3 targets MAT II alpha for ubiquitylation-mediated degradation, so proteomics and ubiquitylation assays are used to monitor MAT2A protein stability and turnover. These methods help define post-translational regulation of the complex.
How CRISPR Can Be Used to Study GO:0048269 methionine adenosyltransferase complex
Knockout
CRISPR knockout of MAT2A, MAT1A or MAT2B is used to deplete specific subunits of the methionine adenosyltransferase complex and to test consequences for SAM levels, splicing and proliferation. MAT2A knockout in MTAP-deleted cancer cells reduces PRMT5-dependent splicing and induces DNA damage, validating the synthetic-lethal relationship.
Point Mutation
Point mutations can be introduced into catalytic residues of MAT2A or MAT1A to separate enzymatic activity from scaffolding or regulatory functions of the complex. Such models help determine whether SAM synthesis itself, or a noncatalytic function, drives downstream phenotypes.
Knock-in
Knock-in of tagged or mutant MAT subunits allows tracking of complex assembly, localization and stability in cells. Tagged knock-in models are useful for proteomic and imaging studies of the methionine adenosyltransferase complex.
Overexpression
Overexpression of MAT2A, MAT1A or MAT2B is used to test whether increased complex activity raises SAM and promotes growth or transformation. Overexpression models complement knockout studies by revealing gain-of-function phenotypes in cancer and metabolic disease.
How EDITGENE Supports methionine adenosyltransferase complex Research
Researchers studying methionine adenosyltransferase complex-related genes often need to determine whether a candidate gene is causally involved in SAM metabolism, methylation-dependent splicing or cancer growth, and which subunit or domain is responsible. Rigorous causal testing requires isogenic cell models in which specific genes are knocked out, mutated, tagged or overexpressed, combined with metabolic and transcriptomic readouts.
Contact EDITGENE today to design your custom CRISPR model for methionine adenosyltransferase complex research.
Frequently Asked Questions About methionine adenosyltransferase complex
What is the methionine adenosyltransferase complex?
The methionine adenosyltransferase complex (GO:0048269) is a multimeric enzyme composed of catalytic alpha subunits and regulatory beta subunits that synthesizes S-adenosylmethionine (SAM), the major methyl-group donor for methylation of proteins, DNA, RNA, phospholipids and small molecules.
What genes are involved in the methionine adenosyltransferase complex?
Key genes include MAT1A and MAT2A, which encode catalytic alpha subunits, and MAT2B, which encodes a regulatory beta subunit; downstream effectors include PRMT5 and RIOK1.
What does GO:0048269 mean?
GO:0048269 is the Gene Ontology cellular-component term for the methionine adenosyltransferase complex, also called the MAT complex, defined by its alpha/beta subunit composition and SAM-synthesizing activity.
Why is MAT2A a cancer target?
MAT2A inhibition blocks the growth of MTAP-deleted cancer cells by reducing PRMT5-dependent mRNA splicing and inducing DNA damage, making MAT2A a synthetic-lethal target.
How is the methionine adenosyltransferase complex regulated?
It is regulated by mTORC1 signaling, cullin 3-mediated ubiquitylation of MAT II alpha, and dietary folate availability, which together tune SAM output to cellular demand.
What is the role of MAT1A in liver cancer?
Hepatic prohibitin 1 and MAT1A defend against primary and secondary liver cancer metastasis, and MAT1A/SAM metabolism is altered in alcohol-associated liver disease.
How do you study the methionine adenosyltransferase complex?
Common methods include metabolomics for SAM, RNA-seq for splicing, m6A profiling, proteomics and ubiquitylation assays, and CRISPR knockout or overexpression models.
What is the relationship between SAM and methylation?
SAM produced by the methionine adenosyltransferase complex is the major methyl-group donor used by methyltransferases such as PRMT5 to modify proteins, DNA, RNA and lipids.
Can MAT2A inhibition be used in MTAP-deleted tumors?
Yes, MTAP deletion creates a vulnerability to MAT2A inhibition, and this synthetic-lethal strategy is an active area of cancer research.
What CRISPR models are useful for MAT complex research?
Knockout, point-mutation, knock-in and overexpression models of MAT1A, MAT2A, MAT2B and related regulators are used to dissect subunit-specific functions and disease mechanisms.
Conclusion
The methionine adenosyltransferase complex (GO:0048269) is a central metabolic enzyme assembly that produces SAM, the universal methyl donor required for DNA, RNA, protein and lipid methylation. Its alpha and beta subunits, including MAT1A, MAT2A and MAT2B, are differentially expressed and regulated, and their dysfunction is linked to cancer, liver disease and metabolic disorders. MAT2A has emerged as a synthetic-lethal target in MTAP-deleted cancers, while MAT1A and prohibitin 1 defend against liver cancer metastasis. Continued research using CRISPR knockout, point-mutation, knock-in and overexpression models, combined with metabolomics and transcriptomics, will clarify how this complex coordinates methylation with cell growth and disease.
References
- 1. Kalev P et al.. 2021. MAT2A Inhibition Blocks the Growth of MTAP-Deleted Cancer Cells by Reducing PRMT5-Dependent mRNA Splicing and Inducing DNA Damage.. Cancer Cell 39(2):209-224.e11 PMID: 33450196
- 2. Villa E et al.. 2021. mTORC1 stimulates cell growth through SAM synthesis and m(6)A mRNA-dependent control of protein synthesis.. Mol Cell 81(10):2076-2093.e9 PMID: 33756106
- 3. Marjon K et al.. 2016. MTAP Deletions in Cancer Create Vulnerability to Targeting of the MAT2A/PRMT5/RIOK1 Axis.. Cell Rep 15(3):574-587 PMID: 27068473
- 4. Fan W et al.. 2024. Hepatic prohibitin 1 and methionine adenosyltransferase α1 defend against primary and secondary liver cancer metastasis.. J Hepatol 80(3):443-453 PMID: 38086446
- 5. Rodon J et al.. 2026. MTAP Deletion in Oncogenesis: A Synthetic Lethality Scenario.. Cancer Res 86(7):1558-1569 PMID: 41512197
- 6. Barbier-Torres L et al.. 2025. Methionine Adenosyltransferase 1A and S-Adenosylmethionine in Alcohol-Associated Liver Disease.. Antioxidants (Basel) 14(12) PMID: 41462685
- 7. Wang J et al.. 2016. Cullin 3 targets methionine adenosyltransferase IIα for ubiquitylation-mediated degradation and regulates colorectal cancer cell proliferation.. FEBS J 283(13):2390-402 PMID: 27213918
- 8. Li JT et al.. 2022. Dietary folate drives methionine metabolism to promote cancer development by stabilizing MAT IIA.. Signal Transduct Target Ther 7(1):192 PMID: 35729157
