GO:0004333 fumarate hydratase activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0004333 fumarate hydratase activity is a molecular function defined as catalysis of the reversible reaction (S)-malate = fumarate + H2O, carried out by the enzyme fumarate hydratase (FH).
• FH is a tumor suppressor; loss-of-function FH variants cause fumarate accumulation, which inhibits alpha-ketoglutarate-dependent dioxygenases and drives kidney cancer and hereditary leiomyomatosis and renal cell cancer.
• Fumarate accumulation links FH activity to innate immunity by promoting mitochondrial RNA and mtDNA release, triggering interferon and inflammatory responses.
• FH activity is regulated by post-translational mechanisms, including HDAC6 inhibition, which alters fumarate hydratase activity and mitochondrial structure.
• FH is a metabolic regulator of immune cell function, influencing macrophage and T cell responses through fumarate-mediated signaling.
• Experimental models for studying GO:0004333 include FH knockout, point-mutation, knock-in, and overexpression cell lines, as well as CRISPR library screening and bioinformatics analysis.
Description
Fumarate hydratase activity (GO:0004333) is a molecular function that catalyzes the reversible hydration of fumarate to (S)-malate, a central step in the tricarboxylic acid (TCA) cycle. The enzyme responsible, fumarate hydratase (FH), is a tumor suppressor whose loss-of-function mutations lead to the accumulation of fumarate, an oncometabolite that inhibits alpha-ketoglutarate-dependent dioxygenases and reprograms cellular metabolism. Because of its dual role in energy metabolism and tumor suppression, FH has become a focal point for cancer biology, immunometabolism, and mitochondrial signaling research. Recent studies have shown that fumarate hydratase activity restrains mitochondrial RNA-mediated interferon production in macrophages, linking the enzyme directly to innate immune regulation. Additionally, fumarate accumulation induced by FH loss promotes vesicular release of mitochondrial DNA, further driving innate immune responses. These findings underscore the importance of precise experimental models to dissect the mechanistic roles of fumarate hydratase activity in health and disease.
fumarate hydratase activity At A Glance
| GO ID | GO:0004333 |
|---|---|
| GO term | fumarate hydratase activity |
| Ontology | molecular_function |
| Synonym | fumarase activity, L-malate hydro-lyase activity, (S)-malate hydro-lyase activity, (S)-malate hydro-lyase (fumarate-forming) |
| Definition | Catalysis of the reaction: (S)-malate = fumarate + H2O. |
| Major function | Reversible interconversion of (S)-malate and fumarate in the TCA cycle |
| Related gene | FH (fumarate hydratase) |
| Associated disease | Hereditary leiomyomatosis and renal cell cancer (HLRCC), fumarate hydratase deficiency |
| Subcellular location | Mitochondrion and cytosol |
What Is GO:0004333?
According to the Gene Ontology, fumarate hydratase activity (GO:0004333) is defined as the catalysis of the reaction: (S)-malate = fumarate + H2O. This reversible dehydration/hydration reaction interconverts malate and fumarate, and is a key step in the TCA cycle. The term is synonymous with fumarase activity, L-malate hydro-lyase activity, (S)-malate hydro-lyase activity, and (S)-malate hydro-lyase (fumarate-forming).
Why Is fumarate hydratase activity Important in Cell Biology?
Fumarate hydratase activity is critical for cellular energy metabolism and tumor suppression. Loss of FH function leads to fumarate accumulation, which acts as an oncometabolite by inhibiting alpha-ketoglutarate-dependent dioxygenases, including histone and DNA demethylases, thereby altering epigenetic landscapes and promoting oncogenesis. FH mutations cause hereditary leiomyomatosis and renal cell cancer (HLRCC) and fumarate hydratase deficiency, a severe metabolic disorder. Beyond cancer, FH activity regulates innate immunity by controlling mitochondrial RNA and DNA release, which triggers interferon and inflammatory responses. Consequently, understanding fumarate hydratase activity is essential for developing targeted therapies and for interpreting metabolic and immune phenotypes in disease models.
• FH is a tumor suppressor; germline mutations cause HLRCC and fumarate hydratase deficiency.
• Fumarate accumulation inhibits alpha-ketoglutarate-dependent dioxygenases, affecting histone and DNA demethylation.
• FH activity restrains mtRNA-mediated interferon production in macrophages.
• Fumarate induces vesicular release of mtDNA, driving innate immunity.
• FH is a metabolic regulator of immune cell function, influencing macrophage and T cell responses.
• FH variant pathogenicity promotes purine salvage pathway dependence in kidney cancer.
• HDAC6 inhibition alters fumarate hydratase activity and mitochondrial structure.
• Bioorthogonal oncometabolite ligation enables detection of fumarate and related metabolites.
• FH activity is essential for TCA cycle function and cellular respiration.
• FH is a target for cancer therapy and immunometabolism research.
Molecular Mechanism of fumarate hydratase activity
Substrate binding and catalytic mechanism
In simple terms: Fumarate hydratase binds malate or fumarate and converts one to the other by adding or removing water.
Fumarate hydratase (FH) catalyzes the reversible hydration of fumarate to (S)-malate. The enzyme operates through a general acid-base mechanism, where a conserved histidine residue acts as a base to abstract a proton from malate, facilitating the elimination of water to form fumarate. The reaction is stereospecific, producing only the (S)-enantiomer of malate. This step is essential for the TCA cycle, linking the oxidation of succinate to the generation of NADH.
Role in the TCA cycle and mitochondrial metabolism
In simple terms: FH is a key enzyme in the citric acid cycle, helping cells produce energy.
In the mitochondrial matrix, fumarate hydratase activity converts fumarate to malate, which is then oxidized to oxaloacetate by malate dehydrogenase. This step contributes to the generation of reducing equivalents (NADH) that fuel oxidative phosphorylation. Loss of FH activity leads to fumarate accumulation, which can inhibit other TCA cycle enzymes and alter mitochondrial respiration.
Fumarate as an oncometabolite and signaling molecule
In simple terms: When FH is lost, fumarate builds up and can change how cells behave, including turning them cancerous.
Fumarate accumulation resulting from FH deficiency inhibits alpha-ketoglutarate-dependent dioxygenases, including histone and DNA demethylases, leading to epigenetic reprogramming. This inhibition contributes to tumorigenesis in HLRCC and other FH-mutant cancers. Additionally, fumarate can modify cysteine residues on proteins via succination, further altering cellular signaling.
Regulation of FH activity by post-translational modifications
In simple terms: FH activity can be turned up or down by chemical changes to the enzyme or its environment.
Recent studies have shown that inhibition of HDAC6 alters fumarate hydratase activity and mitochondrial structure, suggesting that acetylation may regulate FH function. The exact mechanisms remain under investigation, but these findings highlight the potential for pharmacological modulation of FH activity.
FH in innate immunity and mitochondrial nucleic acid release
In simple terms: FH helps keep mitochondrial RNA and DNA inside mitochondria; when FH is lost, these molecules leak out and trigger immune alarms.
Macrophage fumarate hydratase restrains mtRNA-mediated interferon production, indicating that FH activity is required to prevent aberrant innate immune activation. Similarly, fumarate induces vesicular release of mtDNA, which drives innate immunity. These findings link FH activity to the regulation of mitochondrial nucleic acid release and inflammatory signaling.
Key Genes Involved in GO:0004333 fumarate hydratase activity
The following genes and proteins are directly or indirectly involved in fumarate hydratase activity and its regulatory network.
| Gene | Major Role | Research Relevance |
|---|---|---|
| FH | Encodes fumarate hydratase, the enzyme catalyzing GO:0004333 | Tumor suppressor; mutations cause HLRCC and fumarate hydratase deficiency |
| SDH | Succinate dehydrogenase complex, TCA cycle enzyme | Mutations also cause fumarate/succinate accumulation and tumorigenesis |
| HDAC6 | Histone deacetylase 6, regulates acetylation | Inhibition alters fumarate hydratase activity and mitochondrial structure |
| HIF1A | Hypoxia-inducible factor 1-alpha | Stabilized by fumarate-mediated inhibition of prolyl hydroxylases |
| KEAP1 | Kelch-like ECH-associated protein 1 | Fumarate modifies KEAP1, activating NRF2 antioxidant response |
| NRF2 | Nuclear factor erythroid 2-related factor 2 | Activated by fumarate, promotes antioxidant gene expression |
| TET | Ten-eleven translocation enzymes | Inhibited by fumarate, affecting DNA demethylation |
| KDM | Lysine demethylases | Inhibited by fumarate, altering histone methylation |
| MDH2 | Malate dehydrogenase 2 | Converts malate to oxaloacetate in TCA cycle, linked to FH activity |
| CS | Citrate synthase | First step of TCA cycle, upstream of FH |
| ACO2 | Aconitase 2 | Converts citrate to isocitrate, upstream of FH |
| IDH | Isocitrate dehydrogenase | Produces alpha-ketoglutarate, which is affected by fumarate |
| OGDH | Oxoglutarate dehydrogenase | TCA cycle enzyme, sensitive to fumarate inhibition |
| SUCLG1 | Succinate-CoA ligase subunit alpha | TCA cycle enzyme, upstream of FH |
| SDHA | Succinate dehydrogenase complex flavoprotein subunit A | TCA cycle enzyme, mutations cause succinate accumulation |
| MTOR | Mechanistic target of rapamycin | Regulates metabolism and immunity, potentially interacting with FH pathway |
| STING1 | Stimulator of interferon response cGAMP interactor 1 | Mediates mtDNA-induced innate immune signaling |
| CGAS | Cyclic GMP-AMP synthase | Senses mtDNA and activates STING, linked to FH loss |
How Is fumarate hydratase activity Regulated?
Fumarate hydratase activity is regulated at multiple levels. Post-translational modification, such as acetylation, can modulate FH activity; inhibition of HDAC6 alters fumarate hydratase activity and mitochondrial structure. Additionally, FH expression can be influenced by metabolic and immune signaling pathways, including mTOR, which integrates nutrient and energy status to regulate metabolism and immunity. Fumarate itself can feedback-inhibit upstream TCA cycle enzymes, further affecting flux through the pathway. The interplay between FH activity and mitochondrial nucleic acid release is also subject to regulation by innate immune sensors such as cGAS-STING.
fumarate hydratase activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| FH | Hereditary leiomyomatosis and renal cell cancer (HLRCC) | FH knockout or point-mutation cell lines, mouse models |
| FH | Fumarate hydratase deficiency | Patient-derived fibroblasts, CRISPR knock-in of patient variants |
| FH | Innate immune activation and interferon production | Macrophage-specific FH knockout, mtRNA/mtDNA release assays |
| FH | Metabolic reprogramming and purine salvage dependence | FH-mutant kidney cancer cell lines, metabolomics |
| SDH | Succinate dehydrogenase-deficient tumors | SDH knockout models, fumarate/succinate accumulation studies |
Hereditary leiomyomatosis and renal cell cancer (HLRCC)
Germline mutations in FH cause HLRCC, an inherited cancer syndrome characterized by cutaneous and uterine leiomyomas and an aggressive form of renal cell cancer. Loss of fumarate hydratase activity leads to fumarate accumulation, which acts as an oncometabolite by inhibiting alpha-ketoglutarate-dependent dioxygenases, including histone and DNA demethylases, thereby promoting tumorigenesis. FH variant pathogenicity also promotes purine salvage pathway dependence in kidney cancer, offering potential therapeutic targets.
Fumarate hydratase deficiency
Biallelic loss-of-function mutations in FH cause fumarate hydratase deficiency, a rare metabolic disorder presenting with encephalopathy, seizures, and developmental delay. The disease is characterized by elevated fumarate levels in urine and impaired mitochondrial energy metabolism. Early diagnosis and management are critical, and experimental models are essential to understand the pathophysiology.
Innate immunity and inflammation
Fumarate hydratase activity restrains mtRNA-mediated interferon production in macrophages, and fumarate induces vesicular release of mtDNA to drive innate immunity. These findings link FH dysfunction to autoimmune and inflammatory conditions, suggesting that modulating FH activity could have therapeutic potential in immune disorders.
Metabolic reprogramming in cancer
Beyond HLRCC, FH loss and fumarate accumulation contribute to metabolic reprogramming in various cancers, including kidney and other solid tumors. Fumarate inhibits prolyl hydroxylases, stabilizing HIF1A and promoting angiogenesis and glycolysis. Targeting the metabolic dependencies created by FH loss, such as purine salvage, is an active area of research.
From fumarate hydratase activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| What is the effect of complete FH loss on TCA cycle flux? | FH knockout cell lines (e.g., HEK293T, UOK262) |
| How do specific FH point mutations affect enzyme activity? | Point-mutation knock-in cell lines expressing mutant FH |
| Can wild-type FH rescue fumarate accumulation phenotypes? | FH overexpression or knock-in of wild-type FH |
| How does FH loss alter innate immune signaling? | Macrophage-specific FH knockout, mtRNA/mtDNA release assays |
| What is the role of HDAC6 in regulating FH activity? | HDAC6 inhibitor treatment in FH-expressing cells |
| Can CRISPR library screening identify synthetic lethal partners of FH loss? | Genome-wide CRISPR knockout library screening in FH-mutant cells |
How to Study the fumarate hydratase activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Enzymatic activity assay | Fumarate hydratase catalytic activity | Assessing mutant FH function |
| Metabolomics (LC-MS/GC-MS) | Levels of fumarate, malate, and other metabolites | Detecting fumarate accumulation in FH-deficient cells |
| Stable isotope tracing | Flux through TCA cycle | Quantifying metabolic reprogramming |
| CRISPR knockout screening | Gene essentiality and synthetic lethality | Identifying therapeutic targets in FH-mutant cancers |
| Western blot | Protein expression and post-translational modifications | Validating FH knockout or overexpression |
| Immunofluorescence | Subcellular localization and mitochondrial morphology | Studying FH localization and mitochondrial structure |
| RNA-seq | Transcriptional changes | Analyzing immune and metabolic gene expression |
| Bioorthogonal ligation | Detection of fumarate-modified proteins | Identifying succination targets |
Enzymatic activity assays
Fumarate hydratase activity can be measured spectrophotometrically by monitoring the conversion of malate to fumarate at 240 nm or by coupled assays. These methods are used to assess the impact of mutations or inhibitors on enzyme function.
Metabolomics and flux analysis
Mass spectrometry-based metabolomics quantifies fumarate, malate, and other TCA cycle intermediates in cells and tissues. Stable isotope tracing can reveal flux through fumarate hydratase and identify metabolic reprogramming in FH-deficient models.
CRISPR screening and functional genomics
Genome-wide CRISPR knockout screens in FH-mutant cancer cells can identify synthetic lethal interactions and pathways that compensate for loss of fumarate hydratase activity. These screens have highlighted purine salvage pathway dependence in FH-mutant kidney cancer.
Imaging and mitochondrial structure analysis
Fluorescence microscopy and electron microscopy can visualize mitochondrial morphology and assess how changes in fumarate hydratase activity affect mitochondrial structure, as shown with HDAC6 inhibition.
How CRISPR Can Be Used to Study GO:0004333 fumarate hydratase activity
Knockout
CRISPR-Cas9 knockout of FH generates cell models with complete loss of fumarate hydratase activity, mimicking HLRCC and fumarate hydratase deficiency. These models are used to study metabolic reprogramming, oncometabolite accumulation, and innate immune activation.
Point Mutation
CRISPR-mediated point mutations can introduce specific FH variants identified in patients, allowing functional assessment of pathogenicity. Such models help distinguish loss-of-function from hypomorphic alleles and study genotype-phenotype correlations.
Knock-in
Knock-in of wild-type or tagged FH enables rescue experiments and tracking of FH localization and interactions. Tagged knock-in models are valuable for proteomic and imaging studies of fumarate hydratase activity.
Overexpression
CRISPR activation or lentiviral overexpression of FH can elevate fumarate hydratase activity to study its effects on metabolism, immune signaling, and tumor suppression. Overexpression models are useful for testing whether increased FH activity can reverse disease phenotypes.
How EDITGENE Supports fumarate hydratase activity Research
Researchers studying fumarate hydratase activity-related genes often need to determine whether a candidate gene is causally involved in metabolic and immune phenotypes. EDITGENE provides comprehensive CRISPR-based services to generate precisely engineered cell models, enabling rigorous functional validation of genes in the FH pathway.
Contact EDITGENE today to design your custom CRISPR model for fumarate hydratase activity research.
Frequently Asked Questions About fumarate hydratase activity
What is fumarate hydratase activity?
Fumarate hydratase activity (GO:0004333) is the catalysis of the reversible reaction (S)-malate = fumarate + H2O, a key step in the TCA cycle.
What genes are involved in fumarate hydratase activity?
The primary gene is FH, which encodes the enzyme fumarate hydratase. Other related genes include SDH, HDAC6, and HIF1A.
How is fumarate hydratase activity measured?
It is typically measured by spectrophotometric assays monitoring malate to fumarate conversion, or by metabolomics quantifying fumarate levels.
What diseases are associated with fumarate hydratase deficiency?
Fumarate hydratase deficiency causes hereditary leiomyomatosis and renal cell cancer (HLRCC) and a rare metabolic disorder with encephalopathy.
Why is fumarate hydratase a tumor suppressor?
Loss of FH leads to fumarate accumulation, which inhibits alpha-ketoglutarate-dependent dioxygenases, altering epigenetics and promoting cancer.
How does fumarate hydratase affect the immune system?
FH activity restrains mtRNA-mediated interferon production and prevents mtDNA release, thereby limiting innate immune activation.
Can CRISPR be used to study fumarate hydratase activity?
Yes, CRISPR knockout, point mutation, knock-in, and overexpression models are widely used to dissect FH function and identify therapeutic targets.
What is the role of fumarate as an oncometabolite?
Fumarate inhibits alpha-ketoglutarate-dependent dioxygenases, including histone and DNA demethylases, leading to epigenetic changes that drive tumorigenesis.
How does HDAC6 regulate fumarate hydratase activity?
Inhibition of HDAC6 alters fumarate hydratase activity and mitochondrial structure, suggesting acetylation-dependent regulation.
What experimental models are available for fumarate hydratase research?
Models include FH knockout cell lines, point-mutation knock-ins, overexpression systems, and CRISPR library screens, as well as mouse models.
Conclusion
Fumarate hydratase activity (GO:0004333) is a fundamental molecular function in the TCA cycle with critical roles in tumor suppression, metabolism, and immunity. Loss of FH activity leads to fumarate accumulation, an oncometabolite that drives epigenetic reprogramming and cancer, while also modulating innate immune responses. Understanding the regulation and downstream effects of fumarate hydratase activity requires robust experimental models, including CRISPR-engineered cell lines and screening approaches. EDITGENE provides comprehensive services to support such research, from knockout and point-mutation models to library screening and bioinformatics.
References
- 1. Hooftman A et al.. 2023. Macrophage fumarate hydratase restrains mtRNA-mediated interferon production.. Nature 615(7952):490-498 PMID: 36890227
- 2. Roe A et al.. 2025. Inhibition of HDAC6 alters fumarate hydratase activity and mitochondrial structure.. Nat Commun 16(1):6923 PMID: 40721560
- 3. Zecchini V et al.. 2023. Fumarate induces vesicular release of mtDNA to drive innate immunity.. Nature 615(7952):499-506 PMID: 36890229
- 4. Adam MP et al.. 1993. Fumarate Hydratase Deficiency.. PMID: 20301679
- 5. Peace CG et al.. 2024. Fumarate hydratase as a metabolic regulator of immunity.. Trends Cell Biol 34(6):442-450 PMID: 37940417
- 6. Wilde BR et al.. 2023. FH Variant Pathogenicity Promotes Purine Salvage Pathway Dependence in Kidney Cancer.. Cancer Discov 13(9):2072-2089 PMID: 37255402
- 7. Briney CA et al.. 2019. Bioorthogonal oncometabolite ligation.. Methods Enzymol 622:431-448 PMID: 31155064
- 8. Xiao M et al.. 2012. Inhibition of α-KG-dependent histone and DNA demethylases by fumarate and succinate that are accumulated in mutations of FH and SDH tumor suppressors.. Genes Dev 26(12):1326-38 PMID: 22677546
