GO:0008446 GDP-mannose 4,6-dehydratase activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0008446 GDP-mannose 4,6-dehydratase activity catalyzes the dehydration of GDP-alpha-D-mannose to GDP-4-dehydro-6-deoxy-alpha-D-mannose plus water, the first committed step in GDP-L-fucose biosynthesis.
• The enzyme, encoded by GMDS in humans, is a cytosolic, NADP+-dependent short-chain dehydrogenase/reductase that forms a tight complex with the downstream epimerase-reductase FX to channel intermediates and stabilize activity.
• GMDS is a direct protein partner of tankyrase-1 and inhibits its poly(ADP-ribose) polymerase activity, linking GDP-fucose supply to Wnt/beta-catenin signaling and telomere-associated regulation.
• In MYCN-amplified neuroblastoma, GMDS drives core fucosylation and tumorigenesis, and its loss impairs tumor growth, identifying it as a metabolic vulnerability.
• Small-molecule fucostatin inhibitors bind GMDS and modulate antibody fucosylation, showing that the enzyme is a druggable node for therapeutic glycoprotein engineering.
• Gut microbial GDP-mannose 4,6-dehydratase activity contributes to GDP-L-fucose secretion that rescues aging-related intestinal P-glycoprotein damage, expanding its relevance beyond human cells.
Description
GDP-mannose 4,6-dehydratase activity (GO:0008446) is a molecular function that catalyzes the conversion of GDP-alpha-D-mannose into GDP-4-dehydro-6-deoxy-alpha-D-mannose with release of water. This reaction is the first committed and rate-limiting step in the de novo pathway for GDP-L-fucose, the nucleotide sugar donor used by fucosyltransferases in the Golgi apparatus. Because fucosylation controls the properties of glycoproteins and glycolipids, the enzyme sits at the intersection of nucleotide sugar metabolism, glycosylation, and cell signaling. The human enzyme is encoded by GMDS and is a cytosolic protein that functions as a homodimer and associates with the downstream bifunctional enzyme FX (GDP-4-keto-6-deoxymannose-3,5-epimerase-4-reductase) to form a stable biosynthetic complex. Beyond its canonical role, GMDS binds tankyrase-1 and inhibits its poly(ADP-ribose) polymerase activity, providing a direct link between GDP-fucose metabolism and Wnt/beta-catenin signaling. Recent work has also implicated GMDS in cancer: in MYCN-amplified neuroblastoma, GMDS supports core fucosylation and tumorigenesis, and its inhibition reduces tumor growth. In the gut, microbial GDP-mannose 4,6-dehydratase activity contributes to GDP-L-fucose secretion that rescues aging-related intestinal P-glycoprotein damage. These findings make GO:0008446 a compelling target for glycobiology, cancer metabolism, and therapeutic glycoprotein engineering.
GDP-mannose 4,6-dehydratase activity At A Glance
| GO ID | GO:0008446 |
|---|---|
| GO term | GDP-mannose 4,6-dehydratase activity |
| Ontology | molecular_function |
| Synonym | GDP-D-mannose 4,6-dehydratase activity; GDP-D-mannose dehydratase activity; GDPmannose 4,6-dehydratase activity; GDP-mannose 4,6-hydro-lyase activity; Gmd; guanosine 5'-diphosphate-D-mannose oxidoreductase activity; guanosine diphosphomannose 4,6-dehydratase activity; guanosine diphosphomannose oxidoreductase activity |
| Major function | First committed step in GDP-L-fucose biosynthesis; converts GDP-mannose to GDP-4-dehydro-6-deoxy-mannose |
| Cofactor | NADP+ |
| Substrate | GDP-alpha-D-mannose |
| Product | GDP-4-dehydro-6-deoxy-alpha-D-mannose + H2O |
| Cellular location | Cytosol |
| Human gene | GMDS |
| Pathway | De novo GDP-L-fucose biosynthesis; fucosylation |
What Is GO:0008446?
GO:0008446 GDP-mannose 4,6-dehydratase activity is defined by QuickGO as the catalysis of the reaction GDP-alpha-D-mannose = GDP-4-dehydro-6-deoxy-alpha-D-mannose + H2O. In other words, the enzyme removes water from GDP-mannose to generate a 4-keto-6-deoxy intermediate, which is subsequently converted to GDP-L-fucose by downstream enzymes. The reaction is NADP+-dependent and proceeds through a mechanism involving transient oxidation and dehydration.
Why Is GDP-mannose 4,6-dehydratase activity Important in Cell Biology?
GDP-mannose 4,6-dehydratase activity is important because it controls the supply of GDP-L-fucose, the sole nucleotide sugar donor for all fucosylation reactions in the secretory pathway. Fucosylation regulates glycoprotein stability, receptor signaling, immune recognition, and antibody effector function, so changes in GMDS activity have broad physiological and pathological consequences. The enzyme is also a signaling hub: it binds tankyrase-1 and inhibits its PARP activity, thereby influencing Wnt/beta-catenin and telomere-related processes. In cancer, GMDS supports MYCN-amplified neuroblastoma growth through core fucosylation, and small-molecule inhibitors of the enzyme can modulate antibody fucosylation. In the gut, microbial GDP-mannose 4,6-dehydratase activity contributes to GDP-L-fucose secretion that protects intestinal P-glycoprotein during aging. Thus, GO:0008446 is a key node for glycobiology, cancer metabolism, and therapeutic protein engineering.
• Controls the first committed step of GDP-L-fucose biosynthesis, the donor for all fucosylation reactions.
• Supports core fucosylation and tumorigenesis in MYCN-amplified neuroblastoma.
• Binds tankyrase-1 and inhibits its poly(ADP-ribose) polymerase activity, linking metabolism to Wnt/beta-catenin signaling.
• Its activity is stabilized by interaction with the downstream enzyme FX (GDP-4-keto-6-deoxymannose-3,5-epimerase-4-reductase).
• Small-molecule fucostatin inhibitors target GMDS and modulate antibody fucosylation for therapeutic applications.
• Microbial GDP-mannose 4,6-dehydratase activity contributes to GDP-L-fucose secretion that rescues aging-related intestinal P-glycoprotein damage.
• Defects in fucosylation are associated with congenital disorders of glycosylation and immune dysfunction.
• The enzyme is a potential biomarker and therapeutic target in cancers with high fucosylation.
• Its reaction mechanism has been resolved structurally, enabling rational inhibitor design.
• GMDS is a cytosolic enzyme, making it accessible to small-molecule modulation.
Molecular Mechanism of GDP-mannose 4,6-dehydratase activity
Substrate binding and cofactor requirement
In simple terms: The enzyme grabs GDP-mannose and uses NADP+ as a helper to start the reaction.
GDP-mannose 4,6-dehydratase binds GDP-alpha-D-mannose and NADP+ in its active site. The enzyme belongs to the short-chain dehydrogenase/reductase family and uses NADP+ as an oxidizing cofactor to initiate catalysis. Structural and functional studies show that the enzyme forms a homodimer and that the cofactor is essential for activity.
Oxidation and dehydration steps
In simple terms: The enzyme first removes a hydrogen to create a ketone, then removes water to form a double bond.
The catalytic mechanism proceeds through oxidation of the 4-hydroxyl group of GDP-mannose to a 4-keto intermediate, followed by dehydration to remove the 6-hydroxyl group, yielding GDP-4-dehydro-6-deoxy-alpha-D-mannose. This parsimonious mechanism involves a transient NADP+-dependent oxidation and a subsequent elimination reaction. The reaction releases water as a byproduct.
Product release and channeling to FX
In simple terms: The product is handed off to the next enzyme in the pathway so it can be converted to GDP-fucose.
The product GDP-4-dehydro-6-deoxy-alpha-D-mannose is channeled to the bifunctional enzyme FX (GDP-4-keto-6-deoxymannose-3,5-epimerase-4-reductase), which converts it to GDP-L-fucose. Physical interaction between GMDS and FX stabilizes the dehydratase activity and enhances the efficiency of GDP-fucose formation. This complex formation is important for maintaining flux through the de novo pathway.
Regulation by protein-protein interactions
In simple terms: Other proteins can bind to the enzyme and change what it does.
GMDS interacts with tankyrase-1, and this interaction inhibits tankyrase-1 poly(ADP-ribose) polymerase activity. The binding is mediated by specific structural features of GMDS and affects tankyrase-1 stability and function. This cross-talk links GDP-mannose metabolism to Wnt/beta-catenin signaling and telomere regulation.
Inhibition by small molecules
In simple terms: Drug-like molecules can block the enzyme and reduce fucosylation.
Fucostatin inhibitors bind to GMDS and modulate antibody fucosylation, as shown by cocrystal structures. These small molecules provide chemical tools to probe the function of GO:0008446 in cells and to engineer therapeutic glycoproteins with defined fucosylation.
Key Genes Involved in GO:0008446 GDP-mannose 4,6-dehydratase activity
The following genes and proteins are directly involved in or regulate GDP-mannose 4,6-dehydratase activity (GO:0008446) and its downstream pathways.
| Gene | Major Role | Research Relevance |
|---|---|---|
| GMDS | Encodes GDP-mannose 4,6-dehydratase, the enzyme catalyzing GO:0008446 | Core enzyme for GDP-fucose biosynthesis; target in cancer and glycoprotein engineering |
| TSTA3 (FX) | GDP-4-keto-6-deoxymannose-3,5-epimerase-4-reductase, converts GMDS product to GDP-L-fucose | Forms complex with GMDS to stabilize activity |
| TNKS (tankyrase-1) | Binds GMDS and is inhibited by it; regulates Wnt/beta-catenin signaling | Links GDP-mannose metabolism to signaling |
| FUT8 | Alpha-1,6-fucosyltransferase that adds core fucose to N-glycans using GDP-fucose | Downstream consumer of GDP-fucose; affected by GMDS activity |
| FUT2 | Alpha-1,2-fucosyltransferase involved in secretor status and mucosal glycosylation | Uses GDP-fucose produced via GMDS pathway |
| FUT3 | Alpha-1,3/4-fucosyltransferase involved in Lewis antigen synthesis | Depends on GDP-fucose supply |
| SLC35C1 | GDP-fucose transporter into Golgi | Transports the product of the pathway; mutations cause LAD II |
| GFUS (FX) | Alternative name for GDP-fucose synthase | Catalyzes final step of GDP-fucose synthesis |
| GMD (bacterial) | Bacterial homolog of GDP-mannose 4,6-dehydratase | Microbial GDP-fucose production; gut microbiota studies |
| NADP+ | Essential cofactor for the dehydratase reaction | Required for catalytic activity |
| MYCN | Amplified oncogene in neuroblastoma; GMDS supports MYCN-driven tumorigenesis | Therapeutic target in MYCN-amplified neuroblastoma |
| P-glycoprotein (ABCB1) | Efflux pump whose function is rescued by GDP-L-fucose in aging intestine | Links microbial GMDS activity to drug transport |
| Tankyrase-1 (TNKS1) | Poly(ADP-ribose) polymerase inhibited by GMDS binding | Regulates telomeres and Wnt signaling |
| TRF1 | Telomeric repeat-binding factor 1, partner of tankyrase-1 | Context for GMDS-tankyrase interaction |
| Fucostatin (chemical) | Small-molecule inhibitor of GMDS | Modulates antibody fucosylation |
| GMDS (human) | Cytosolic enzyme; homodimer | Structural and mechanistic studies |
| GDP-mannose | Substrate of the reaction | Metabolic flux studies |
| GDP-fucose | Product of the pathway; donor for fucosyltransferases | Glycosylation engineering |
How Is GDP-mannose 4,6-dehydratase activity Regulated?
GDP-mannose 4,6-dehydratase activity is regulated at multiple levels. The enzyme requires NADP+ as a cofactor, and its activity is stabilized by physical interaction with the downstream enzyme FX (TSTA3/GFUS), which forms a complex with GMDS and enhances GDP-fucose production. GMDS also binds tankyrase-1 and inhibits its poly(ADP-ribose) polymerase activity, suggesting that the interaction reciprocally regulates both proteins. In cancer, MYCN amplification is associated with increased GMDS expression and core fucosylation, indicating that oncogenic signaling can drive pathway flux. Small-molecule fucostatin inhibitors can directly block GMDS activity, providing a pharmacological means of regulation. Microbial GDP-mannose 4,6-dehydratase activity in the gut contributes to GDP-L-fucose secretion that affects host intestinal P-glycoprotein, illustrating environmental regulation.
GDP-mannose 4,6-dehydratase activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| GMDS | MYCN-amplified neuroblastoma | GMDS knockout or knockdown in neuroblastoma cell lines; xenograft models |
| GMDS | Congenital disorders of glycosylation / LAD II | Patient-derived fibroblasts; CRISPR knock-in of patient mutations |
| GMDS (microbial) | Aging-related intestinal P-glycoprotein damage | Gnotobiotic mice colonized with Odoribacter splanchnicus; fecal microbiota transplantation |
| GMDS | Antibody fucosylation for therapeutic engineering | CHO cells with GMDS knockout or fucostatin treatment |
| TNKS1 | Wnt/beta-catenin signaling and telomere regulation | GMDS-tankyrase interaction studies; tankyrase inhibitor assays |
Cancer: MYCN-amplified neuroblastoma
GMDS is a key driver of MYCN-amplified neuroblastoma core fucosylation and tumorigenesis. Loss of GMDS impairs core fucosylation and reduces tumor growth in models of MYCN-amplified neuroblastoma. These findings identify GMDS as a metabolic vulnerability and potential therapeutic target in this aggressive pediatric cancer.
Congenital disorders of glycosylation and immune dysfunction
Defects in GDP-fucose biosynthesis, including impaired GDP-mannose 4,6-dehydratase activity, can lead to leukocyte adhesion deficiency type II (LAD II) and other congenital disorders of glycosylation. Because GDP-fucose is required for selectin ligand fucosylation, reduced pathway flux impairs immune cell trafficking and host defense.
Aging-related intestinal dysfunction
Microbial GDP-mannose 4,6-dehydratase activity contributes to GDP-L-fucose secretion by gut bacteria such as Odoribacter splanchnicus, which rescues aging-related intestinal P-glycoprotein damage. This highlights a role for the enzyme in host-microbe interactions and intestinal homeostasis during aging.
Therapeutic glycoprotein engineering
Small-molecule fucostatin inhibitors of GMDS modulate antibody fucosylation, which is critical for antibody-dependent cellular cytotoxicity. Manipulating GO:0008446 activity therefore has direct applications in biotherapeutic production and glycoengineering.
From GDP-mannose 4,6-dehydratase activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of GMDS reduce tumor growth? | GMDS knockout in MYCN-amplified neuroblastoma cell lines and xenografts |
| How does GMDS mutation affect GDP-fucose levels? | Point-mutation knock-in of catalytic residues in GMDS |
| Can GMDS be targeted to modulate antibody fucosylation? | GMDS knockout or fucostatin treatment in CHO cells |
| Does GMDS interact with tankyrase-1 in vivo? | Tagged knock-in of GMDS with affinity tags for co-immunoprecipitation |
| What is the role of microbial GMDS in gut homeostasis? | Bacterial GMDS knockout in Odoribacter splanchnicus; mouse colonization |
| How does GMDS overexpression affect fucosylation? | GMDS overexpression in cell lines followed by lectin blotting |
How to Study the GDP-mannose 4,6-dehydratase activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| HPLC/MS enzymatic assay | Conversion of GDP-mannose to GDP-4-dehydro-6-deoxy-mannose | Direct measurement of GO:0008446 activity |
| Coupled FX assay | GDP-fucose production | Pathway flux analysis |
| Lectin blotting | Cellular fucosylation levels | Functional readout of GMDS activity |
| LC-MS glycomics | N-glycan structures and core fucosylation | Antibody glycoengineering |
| Co-immunoprecipitation | Protein-protein interactions (GMDS-tankyrase, GMDS-FX) | Signaling cross-talk studies |
| X-ray crystallography | Three-dimensional structure and inhibitor binding | Rational drug design |
| CRISPR knockout screening | Gene essentiality and pathway dependencies | Cancer target discovery |
| NADP+ consumption assay | Enzyme kinetics and cofactor requirement | Mechanistic studies |
Enzymatic assays for GDP-mannose 4,6-dehydratase activity
Direct measurement of GO:0008446 activity can be performed using purified enzyme or cell lysates by monitoring the conversion of GDP-mannose to GDP-4-dehydro-6-deoxy-mannose via HPLC or mass spectrometry. Coupled assays with FX (TSTA3) can measure GDP-fucose formation. NADP+ reduction or consumption can also be monitored spectrophotometrically.
Glycosylation analysis
Changes in GMDS activity affect cellular fucosylation, which can be assessed by lectin blotting with fucose-specific lectins, mass spectrometry of N-glycans, or antibody glycan profiling. Core fucosylation of specific proteins can be quantified using PNGase F treatment followed by LC-MS.
Protein-protein interaction studies
Co-immunoprecipitation, pull-down assays, and proximity ligation can detect the interaction between GMDS and tankyrase-1 or FX. Structural studies such as X-ray crystallography and cocrystallization with inhibitors reveal binding interfaces.
CRISPR-based functional genomics
CRISPR knockout screens can identify GMDS as a dependency in cancer cell lines, particularly MYCN-amplified neuroblastoma. Point-mutation knock-in of catalytic residues can dissect the enzymatic versus non-enzymatic functions of GMDS.
How CRISPR Can Be Used to Study GO:0008446 GDP-mannose 4,6-dehydratase activity
Knockout
CRISPR knockout of GMDS eliminates GDP-mannose 4,6-dehydratase activity, reducing GDP-fucose levels and cellular fucosylation. This model is used to test whether GMDS is required for tumor growth, especially in MYCN-amplified neuroblastoma, and to study the impact of fucosylation loss on signaling and immune recognition.
Point Mutation
Point-mutation knock-in of catalytic residues in GMDS can separate its enzymatic activity from its protein-protein interaction functions, such as tankyrase-1 binding. Such models help dissect the contribution of GO:0008446 catalysis to specific phenotypes.
Knock-in
Knock-in of epitope tags or fluorescent reporters into the endogenous GMDS locus enables real-time tracking of enzyme localization, interaction, and turnover. Knock-in of disease-associated mutations can model congenital disorders of glycosylation.
Overexpression
Overexpression of GMDS increases GDP-fucose production and core fucosylation, which can enhance antibody-dependent cellular cytotoxicity in engineered cell lines. This approach is used to study the consequences of elevated pathway flux in cancer and glycoprotein production.
How EDITGENE Supports GDP-mannose 4,6-dehydratase activity Research
Researchers studying GDP-mannose 4,6-dehydratase activity-related genes often need to determine whether a candidate gene is causally involved in fucosylation, cancer growth, or signaling. EDITGENE provides CRISPR-based cell model services to enable precise genetic manipulation of GMDS and its pathway partners.
Contact EDITGENE today to design your custom CRISPR model for GDP-mannose 4,6-dehydratase activity research.
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| GMDS Knockout HEK293 Cell Line | EDJ-KQ4727 | Human | 2762 | Details Get a Quote |
| GMDS Knockout HCT 116 Cell Line | EDJ-KQ26226 | Human | 2762 | Details Get a Quote |
| GMDS Knockout A-549 Cell Line | EDJ-KQ27462 | Human | 2762 | Details Get a Quote |
| GMDS Knockout HeLa Cell Line | EDJ-KQ27464 | Human | 2762 | Details Get a Quote |
Displaying Records 1 To 4 Of 4 Records
Frequently Asked Questions About GDP-mannose 4,6-dehydratase activity
What is GDP-mannose 4,6-dehydratase activity?
It is the enzymatic activity (GO:0008446) that converts GDP-alpha-D-mannose to GDP-4-dehydro-6-deoxy-alpha-D-mannose and water, the first committed step in GDP-L-fucose biosynthesis.
What gene encodes GDP-mannose 4,6-dehydratase in humans?
The human gene is GMDS, which encodes a cytosolic enzyme that forms a homodimer and requires NADP+.
What is the role of GDP-mannose 4,6-dehydratase in fucosylation?
It produces the precursor for GDP-L-fucose, the donor substrate for all fucosyltransferases, thereby controlling core fucosylation of glycoproteins.
How is GDP-mannose 4,6-dehydratase regulated?
Its activity is stabilized by interaction with the downstream enzyme FX (TSTA3/GFUS) and is inhibited by small molecules such as fucostatin; it also binds tankyrase-1.
What diseases are associated with GDP-mannose 4,6-dehydratase?
GMDS supports MYCN-amplified neuroblastoma growth, and defects in GDP-fucose synthesis cause congenital disorders of glycosylation such as LAD II.
What is the reaction catalyzed by GDP-mannose 4,6-dehydratase?
The enzyme catalyzes GDP-alpha-D-mannose = GDP-4-dehydro-6-deoxy-alpha-D-mannose + H2O.
What cofactor does GDP-mannose 4,6-dehydratase require?
It requires NADP+ as an oxidizing cofactor for the dehydration reaction.
How can I study GDP-mannose 4,6-dehydratase activity in the lab?
You can use enzymatic assays with HPLC/MS, coupled assays with FX, lectin blotting for fucosylation, and CRISPR knockout models.
What is the link between GDP-mannose 4,6-dehydratase and tankyrase-1?
GMDS binds tankyrase-1 and inhibits its poly(ADP-ribose) polymerase activity, connecting GDP-mannose metabolism to Wnt/beta-catenin signaling.
Can GDP-mannose 4,6-dehydratase be targeted for antibody engineering?
Yes, small-molecule fucostatin inhibitors of GMDS modulate antibody fucosylation, which affects antibody-dependent cellular cytotoxicity.
Conclusion
GDP-mannose 4,6-dehydratase activity (GO:0008446) is a central enzymatic step in GDP-L-fucose biosynthesis and a key regulator of fucosylation, cancer metabolism, and host-microbe interactions. Its dual role as a metabolic enzyme and a tankyrase-1 binding partner makes it an attractive target for therapeutic intervention and glycoprotein engineering. Understanding its mechanism, regulation, and disease relevance requires precise genetic models, which can be generated using CRISPR-based knockout, knock-in, and overexpression approaches.
References
- 1. Zhu B et al.. 2025. GDP-mannose 4,6-dehydratase is a key driver of MYCN-amplified neuroblastoma core fucosylation and tumorigenesis.. Oncogene 44(18):1272-1283 PMID: 39956863
- 2. Pfeiffer M et al.. 2019. A Parsimonious Mechanism of Sugar Dehydration by Human GDP-Mannose-4,6-dehydratase.. ACS Catal 9(4):2962-2968 PMID: 30984471
- 3. Cui C et al.. 2025. Odoribacter splanchnicus rescues aging-related intestinal P-glycoprotein damage via GDP-L-fucose secretion.. Nat Commun 16(1):10665 PMID: 41309616
- 4. Sullivan FX et al.. 1998. Molecular cloning of human GDP-mannose 4,6-dehydratase and reconstitution of GDP-fucose biosynthesis in vitro.. J Biol Chem 273(14):8193-202 PMID: 9525924
- 5. Eisemann T et al.. 2019. Structural and functional analysis of parameters governing tankyrase-1 interaction with telomeric repeat-binding factor 1 and GDP-mannose 4,6-dehydratase.. J Biol Chem 294(40):14574-14590 PMID: 31375564
- 6. Nakayama K et al.. 2003. Interaction of GDP-4-keto-6-deoxymannose-3,5-epimerase-4-reductase with GDP-mannose-4,6-dehydratase stabilizes the enzyme activity for formation of GDP-fucose from GDP-mannose.. Glycobiology 13(10):673-80 PMID: 12881408
- 7. Bisht KK et al.. 2012. GDP-mannose-4,6-dehydratase is a cytosolic partner of tankyrase 1 that inhibits its poly(ADP-ribose) polymerase activity.. Mol Cell Biol 32(15):3044-53 PMID: 22645305
- 8. Allen JG et al.. 2016. Facile Modulation of Antibody Fucosylation with Small Molecule Fucostatin Inhibitors and Cocrystal Structure with GDP-Mannose 4,6-Dehydratase.. ACS Chem Biol 11(10):2734-2743 PMID: 27434622
