GO:0004488 methylenetetrahydrofolate dehydrogenase (NADP+) activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0004488 describes the NADP+-dependent oxidation of 5,10-methylene-tetrahydrofolate to 5,10-methenyl-tetrahydrofolate, a key step in one-carbon metabolism.
• The activity is carried by bifunctional enzymes such as MTHFD1 (cytosolic) and MTHFD2 (mitochondrial), which also possess cyclohydrolase and formyl-THF synthetase activities.
• MTHFD2 is a metabolic checkpoint in T cells and supports mitochondrial translation through folate-dependent tRNA methylation.
• Inhibition of MTHFD1 causes formate overflow and toxic folate trapping in cancer cells, highlighting the pathway as a therapeutic target.
• NADPH produced by this reaction contributes to redox balance; elevating cytosolic NADPH metabolism ameliorates vascular aging.
• The activity is regulated by substrate availability, NADP+/NADPH ratio, and allosteric effects of 2',5'-ADP, and is a target for antifolate drug design.
Description
Methylenetetrahydrofolate dehydrogenase (NADP+) activity (GO:0004488) catalyzes the reversible conversion of (6R)-5,10-methylene-5,6,7,8-tetrahydrofolate to (6R)-5,10-methenyltetrahydrofolate with concomitant reduction of NADP+ to NADPH. This reaction is a central node in one-carbon metabolism, linking the folate cycle to nucleotide biosynthesis, amino acid homeostasis, and redox balance. In eukaryotes, the activity is typically found in bifunctional or trifunctional enzymes: the cytosolic MTHFD1 and the mitochondrial MTHFD2 (and its homolog MTHFD2L). Because one-carbon units are essential for purine and thymidylate synthesis, methylation reactions, and mitochondrial translation, dysregulation of this activity has profound consequences for cell proliferation, immune function, and aging. Researchers study GO:0004488 to understand how cells partition one-carbon units between biosynthesis and methylation, and to develop inhibitors for cancer and immune disorders.
methylenetetrahydrofolate dehydrogenase (NADP+) activity At A Glance
| GO ID | GO:0004488 |
|---|---|
| GO term | methylenetetrahydrofolate dehydrogenase (NADP+) activity |
| Ontology | molecular_function |
| Synonym | 5,10-methylenetetrahydrofolate:NADP oxidoreductase activity; 5,10-methylenetetrahydrofolate:NADP+ oxidoreductase activity |
| Major function | Catalyzes the NADP+-dependent oxidation of 5,10-methylene-THF to 5,10-methenyl-THF, a key step in one-carbon metabolism. |
| EC number | 1.5.1.5 (as per IUBMB) |
| Cofactor | NADP+ (oxidized form) as electron acceptor; NADPH is produced. |
| Substrate | (6R)-5,10-methylene-5,6,7,8-tetrahydrofolate. |
| Product | (6R)-5,10-methenyltetrahydrofolate and NADPH. |
| Localization | Cytosol (MTHFD1) and mitochondria (MTHFD2/MTHFD2L). |
What Is GO:0004488?
GO:0004488 is defined as the catalysis of the reaction: (6R)-5,10-methylene-5,6,7,8-tetrahydrofolate + NADP+ = (6R)-5,10-methenyltetrahydrofolate + NADPH. In other words, it is an oxidoreductase that uses NADP+ as the electron acceptor to convert a methylene-substituted tetrahydrofolate into a methenyl-substituted form, generating NADPH. This activity is synonymous with 5,10-methylenetetrahydrofolate:NADP oxidoreductase activity and is often part of a larger multifunctional enzyme complex.
Why Is methylenetetrahydrofolate dehydrogenase (NADP+) activity Important in Cell Biology?
GO:0004488 is essential for one-carbon metabolism, which supplies methyl groups for nucleotide synthesis, amino acid interconversion, and methylation reactions. Its activity influences cell proliferation, mitochondrial translation, and redox homeostasis, making it a critical determinant of cancer cell survival, immune cell fate, and vascular aging. Pharmacological inhibition of this activity can selectively kill cancer cells by causing formate overflow and folate trapping, and it is a target for antifolate drugs.
• Supplies one-carbon units for de novo purine and thymidylate synthesis, essential for DNA replication.
• Generates NADPH, contributing to cellular antioxidant defense and reductive biosynthesis.
• Supports mitochondrial translation via folate-dependent tRNA methylation.
• Regulates effector and regulatory T cell fate and function through MTHFD2.
• Its inhibition causes toxic folate trapping and formate overflow in cancer cells.
• Is a target for antifolate chemotherapy and immunotherapy.
• Dysregulation is linked to vascular aging and endothelial dysfunction.
• Plays a role in purine de novo synthesis regulation via non-enzymatic Nudix hydrolase 5.
• Bifunctional enzymes with this activity are potential drug targets due to their unique 2',5'-ADP binding site.
• Activity varies between normal and oncogene-transformed cells, suggesting isoform-specific roles.
Molecular Mechanism of methylenetetrahydrofolate dehydrogenase (NADP+) activity
Substrate Binding and Catalysis
In simple terms: The enzyme grabs a folate molecule and a NADP+ molecule, then rearranges the folate while transferring electrons to NADP+.
The enzyme binds (6R)-5,10-methylene-5,6,7,8-tetrahydrofolate and NADP+ in a sequential ordered mechanism. The oxidation of the methylene group to a methenyl group occurs with hydride transfer to NADP+, forming NADPH and (6R)-5,10-methenyltetrahydrofolate. This reaction is reversible and can proceed in the opposite direction under physiological NADPH/NADP+ ratios.
Bifunctional Enzyme Architecture
In simple terms: The same protein often contains two or three enzymatic activities, allowing efficient channeling of folate intermediates.
In humans, MTHFD1 is a trifunctional enzyme with methylenetetrahydrofolate dehydrogenase, methenyltetrahydrofolate cyclohydrolase, and formyltetrahydrofolate synthetase activities. MTHFD2 is a bifunctional mitochondrial enzyme with dehydrogenase and cyclohydrolase activities. The dehydrogenase domain catalyzes the NADP+-dependent step, while the cyclohydrolase domain converts the product to 10-formyl-THF.
Role of 2',5'-ADP Binding
In simple terms: A small molecule called 2',5'-ADP can bind to the enzyme and change its shape, affecting its activity.
Binding of 2',5'-ADP to the human NADP+-dependent methylenetetrahydrofolate dehydrogenase/cyclohydrolase stimulates the cyclohydrolase activity, suggesting an allosteric regulatory site. This modulation may coordinate the two activities within the bifunctional enzyme.
NADPH Production and Redox Balance
In simple terms: The reaction produces NADPH, a molecule that helps protect cells from oxidative stress.
The NADPH generated by GO:0004488 contributes to the cellular pool of reducing equivalents. Elevating cytosolic NADPH metabolism in endothelial cells ameliorates vascular aging, indicating that this activity supports redox homeostasis. In cancer cells, inhibition of MTHFD1 leads to formate overflow and toxic folate trapping, disrupting redox balance and nucleotide synthesis.
Regulation by Folate Polyglutamation
In simple terms: Folate molecules with multiple glutamate tails are better substrates and are retained in cells.
Pteroylpolyglutamates are the preferred substrates for many folate-dependent enzymes, including methylenetetrahydrofolate dehydrogenase. Polyglutamation increases the affinity of the enzyme for folate substrates and ensures their cellular retention, thereby regulating flux through the pathway.
Key Genes Involved in GO:0004488 methylenetetrahydrofolate dehydrogenase (NADP+) activity
The following genes encode enzymes that possess or are directly associated with methylenetetrahydrofolate dehydrogenase (NADP+) activity.
| Gene | Major Role | Research Relevance |
|---|---|---|
| MTHFD1 | Trifunctional cytosolic enzyme with dehydrogenase, cyclohydrolase, and synthetase activities | Target for antifolate drugs; inhibition causes formate overflow in cancer |
| MTHFD2 | Bifunctional mitochondrial enzyme with dehydrogenase and cyclohydrolase activities | Metabolic checkpoint in T cell fate; supports mitochondrial translation |
| MTHFD2L | Mitochondrial enzyme with dehydrogenase and cyclohydrolase activities | Compensates for MTHFD2 loss in some tissues |
| MTHFD1L | Mitochondrial monofunctional formyl-THF synthetase | Supplies formate for cytosolic one-carbon metabolism |
| SHMT1 | Serine hydroxymethyltransferase, cytosolic | Generates 5,10-methylene-THF for MTHFD1 |
| SHMT2 | Serine hydroxymethyltransferase, mitochondrial | Generates 5,10-methylene-THF for MTHFD2 |
| MTR | Methionine synthase | Consumes 5-methyl-THF, indirectly affecting folate cycle |
| MTHFR | Methylenetetrahydrofolate reductase | Competes for 5,10-methylene-THF, regulating folate distribution |
| TYMS | Thymidylate synthase | Consumes 5,10-methylene-THF for dTMP synthesis |
| GART | Phosphoribosylglycinamide formyltransferase | Uses 10-formyl-THF for purine synthesis |
| ATIC | AICAR transformylase/IMP cyclohydrolase | Uses 10-formyl-THF for purine synthesis |
| NUDT5 | Nudix hydrolase 5 | Non-enzymatic role in repressing purine de novo synthesis |
| ALDH1L1 | 10-formyltetrahydrofolate dehydrogenase | Regulates folate pool by oxidizing 10-formyl-THF |
| ALDH1L2 | Mitochondrial 10-formyltetrahydrofolate dehydrogenase | Mitochondrial folate regulation |
| SLC19A1 | Reduced folate carrier | Transports folates into cells |
| FPGS | Folylpolyglutamate synthase | Adds glutamate tails to folates, enhancing retention |
| GGH | Gamma-glutamyl hydrolase | Removes glutamate tails, affecting folate turnover |
How Is methylenetetrahydrofolate dehydrogenase (NADP+) activity Regulated?
The activity of methylenetetrahydrofolate dehydrogenase (NADP+) is regulated at multiple levels. Substrate availability, particularly the concentration of 5,10-methylene-THF and NADP+, directly influences flux. The NADPH/NADP+ ratio can shift the reaction equilibrium. Allosteric regulation by 2',5'-ADP stimulates the cyclohydrolase activity of the bifunctional enzyme, potentially coordinating the two reactions. Polyglutamation of folates increases substrate affinity and cellular retention, effectively regulating enzyme activity. In cancer cells, inhibition of MTHFD1 leads to formate overflow and toxic folate trapping, indicating that feedback mechanisms exist to maintain one-carbon homeostasis. Additionally, MTHFD2 expression is induced in activated T cells, suggesting transcriptional regulation in immune responses.
methylenetetrahydrofolate dehydrogenase (NADP+) activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| MTHFD2 | Cancer, T cell function | MTHFD2 knockout in cancer cell lines and T cells |
| MTHFD1 | Cancer, folate trapping | MTHFD1 inhibition in cancer cells, formate overflow assays |
| MTHFD1 | Vascular aging | Endothelial cell models with NADPH modulation |
| NUDT5 | Purine metabolism | NUDT5 knockout in cell lines, purine synthesis assays |
| MTHFD2 | Mitochondrial translation | MTHFD2 knockout, tRNA methylation analysis |
Cancer Metabolism
MTHFD2 is overexpressed in many cancers and supports proliferation by supplying one-carbon units for nucleotide synthesis and maintaining mitochondrial translation. Inhibition of MTHFD1 causes formate overflow and toxic folate trapping, selectively killing cancer cells. The NADP+-dependent dehydrogenase activity is therefore a promising target for anticancer therapy.
Immune Cell Function and Autoimmunity
MTHFD2 acts as a metabolic checkpoint controlling effector and regulatory T cell fate and function. Dysregulation of this activity may contribute to autoimmune diseases and affect immunotherapy outcomes.
Vascular Aging
Elevating cytosolic NADPH metabolism in endothelial cells ameliorates vascular aging, linking GO:0004488 activity to redox balance and age-related vascular dysfunction.
Purine Metabolism Disorders
Nudix hydrolase 5 represses purine de novo synthesis through a non-enzymatic mechanism, interacting with the folate cycle. Defects in one-carbon metabolism can lead to purine imbalances and related disorders.
From methylenetetrahydrofolate dehydrogenase (NADP+) activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does MTHFD2 loss affect T cell fate? | MTHFD2 knockout mice or T cell-specific KO |
| Can MTHFD1 inhibition trap folates? | MTHFD1 point mutation or knockout cancer cells |
| Does NADPH production by MTHFD1 affect aging? | Endothelial cell overexpression of MTHFD1 |
| Is the dehydrogenase activity required for mitochondrial translation? | MTHFD2 catalytic-dead knock-in |
| How does NUDT5 regulate purine synthesis? | NUDT5 knockout and overexpression |
| What is the role of 2',5'-ADP binding? | MTHFD1 point mutations in ADP-binding site |
How to Study the methylenetetrahydrofolate dehydrogenase (NADP+) activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| NADPH absorbance assay | Dehydrogenase activity | Kinetic studies, inhibitor screening |
| 13C tracing | Metabolic flux | One-carbon metabolism in cancer |
| CRISPR knockout screen | Gene essentiality | Synthetic lethality with antifolates |
| LC-MS metabolomics | Folate intermediates | Pathway dysregulation |
| Western blot | Protein expression | MTHFD1/2 levels in tissues |
| Ribo-seq | Translation efficiency | Mitochondrial translation |
| Immunofluorescence | Subcellular localization | MTHFD2 in mitochondria |
| NADPH/NADP+ ratio assay | Redox state | Vascular aging studies |
Enzymatic Activity Assays
Direct measurement of methylenetetrahydrofolate dehydrogenase activity using spectrophotometric assays that monitor NADPH production at 340 nm. These assays can be performed with purified recombinant enzymes or cell lysates to assess kinetic parameters and inhibitor efficacy.
Metabolic Flux Analysis
Stable isotope tracing with 13C-labeled serine or formate can quantify flux through the folate cycle and assess the contribution of GO:0004488 to one-carbon metabolism. This method reveals formate overflow and folate trapping in cancer cells.
CRISPR Screening
Genome-wide CRISPR knockout screens can identify genes whose loss affects cell fitness in the presence of MTHFD1 or MTHFD2 inhibitors, uncovering synthetic lethal interactions. Such screens help map the genetic dependencies of one-carbon metabolism.
Proteomics and Metabolomics
Mass spectrometry-based proteomics can quantify MTHFD1/2 protein levels, while metabolomics measures folate intermediates and NADPH/NADP+ ratios. These approaches provide a systems-level view of pathway regulation.
How CRISPR Can Be Used to Study GO:0004488 methylenetetrahydrofolate dehydrogenase (NADP+) activity
Knockout
CRISPR knockout of MTHFD1 or MTHFD2 eliminates the dehydrogenase activity, allowing researchers to study its role in cell proliferation, T cell function, and mitochondrial translation. Knockout models have revealed that MTHFD2 is essential for effector T cell expansion and that its loss impairs mitochondrial translation.
Point Mutation
Introducing point mutations in the catalytic domain of MTHFD1 or MTHFD2 can abolish dehydrogenase activity while preserving other functions, enabling precise dissection of the NADP+-dependent step. Such mutants help distinguish the dehydrogenase activity from the cyclohydrolase activity within bifunctional enzymes.
Knock-in
Knock-in of tagged MTHFD2 (e.g., FLAG or GFP) allows affinity purification and localization studies, facilitating the identification of interacting partners and post-translational modifications. Tagged knock-in models also enable live-cell imaging of mitochondrial folate enzymes.
Overexpression
Overexpression of MTHFD1 or MTHFD2 in cell lines can elevate NADPH production and one-carbon flux, mimicking the metabolic state of cancer cells. This approach is useful for studying redox balance and resistance to antifolates.
How EDITGENE Supports methylenetetrahydrofolate dehydrogenase (NADP+) activity Research
Researchers studying methylenetetrahydrofolate dehydrogenase (NADP+) activity-related genes often need to determine whether a candidate gene is causally involved in one-carbon metabolism, immune regulation, or cancer. EDITGENE provides a comprehensive suite of CRISPR services to create precise cellular models for such investigations.
Contact EDITGENE today to design your custom CRISPR model for methylenetetrahydrofolate dehydrogenase (NADP+) activity research.
Frequently Asked Questions About methylenetetrahydrofolate dehydrogenase (NADP+) activity
What is methylenetetrahydrofolate dehydrogenase (NADP+) activity?
It is the enzymatic activity defined by GO:0004488 that converts 5,10-methylene-tetrahydrofolate to 5,10-methenyl-tetrahydrofolate using NADP+ as a cofactor, producing NADPH.
What genes encode methylenetetrahydrofolate dehydrogenase (NADP+) activity?
The main genes are MTHFD1 (cytosolic trifunctional) and MTHFD2 (mitochondrial bifunctional), with MTHFD2L as a related mitochondrial enzyme.
What is the role of MTHFD2 in T cells?
MTHFD2 acts as a metabolic checkpoint controlling effector and regulatory T cell fate and function.
How is methylenetetrahydrofolate dehydrogenase activity measured?
It is typically measured by spectrophotometric assays monitoring NADPH production at 340 nm using purified enzyme or cell lysates.
What diseases are associated with MTHFD1 and MTHFD2?
They are linked to cancer, immune disorders, and vascular aging, with MTHFD2 overexpression in many tumors.
Can CRISPR be used to study methylenetetrahydrofolate dehydrogenase?
Yes, CRISPR knockout, point mutation, knock-in, and overexpression models are widely used to dissect the function of MTHFD1 and MTHFD2.
What is the difference between MTHFD1 and MTHFD2?
MTHFD1 is cytosolic and trifunctional, while MTHFD2 is mitochondrial and bifunctional; both possess NADP+-dependent dehydrogenase activity.
How does folate polyglutamation affect this activity?
Polyglutamation increases substrate affinity and cellular retention, enhancing the activity of folate-dependent enzymes like MTHFD1.
What is the role of NADPH produced by this reaction?
NADPH contributes to redox homeostasis and reductive biosynthesis; its elevation ameliorates vascular aging.
What happens when MTHFD1 is inhibited in cancer cells?
Inhibition causes formate overflow and toxic folate trapping, leading to impaired nucleotide synthesis and cell death.
Conclusion
GO:0004488, methylenetetrahydrofolate dehydrogenase (NADP+) activity, is a cornerstone of one-carbon metabolism with far-reaching implications for cancer, immunology, and aging. Its bifunctional enzyme architecture and NADPH production make it a compelling target for therapeutic intervention. Continued research using CRISPR models and metabolic profiling will unravel its precise roles in health and disease.
References
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- 2. Wu D et al.. 2025. Elevating cytosolic NADPH metabolism in endothelial cells ameliorates vascular aging.. Nat Commun 16(1):9667 PMID: 41184229
- 3. Morscher RJ et al.. 2018. Mitochondrial translation requires folate-dependent tRNA methylation.. Nature 554(7690):128-132 PMID: 29364879
- 4. Nguyen TA et al.. 2025. A non-enzymatic role of Nudix hydrolase 5 in repressing purine de novo synthesis.. Science 390(6778):1143-1150 PMID: 41196952
- 5. Kisliuk RL. 1981. Pteroylpolyglutamates.. Mol Cell Biochem 39:331-45 PMID: 6458763
- 6. Green AC et al.. 2023. Formate overflow drives toxic folate trapping in MTHFD1 inhibited cancer cells.. Nat Metab 5(4):642-659 PMID: 37012496
- 7. Pelletier JN et al.. 1994. Binding of the 2',5'-ADP subsite stimulates cyclohydrolase activity of human NADP(+)-dependent methylenetetrahydrofolate dehydrogenase/cyclohydrolase.. Biochemistry 33(7):1900-6 PMID: 8110794
- 8. Smith GK et al.. 1990. Activity of an NAD-dependent 5,10-methylenetetrahydrofolate dehydrogenase in normal tissue, neoplastic cells, and oncogene-transformed cells.. Arch Biochem Biophys 283(2):367-71 PMID: 2275549
