GO:0004756 selenide, water dikinase activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0004756 (selenide, water dikinase activity) catalyzes the ATP-dependent conversion of hydrogen selenide to selenophosphate, the reactive selenium donor used for selenocysteine and selenouridine biosynthesis.
• The reaction consumes ATP and water and releases AMP, phosphate, protons, and selenophosphorate, making it the committed step in biological selenium utilization.
• SEPHS1 and SEPHS2 are the principal human genes encoding selenophosphate synthetase activity, with SEPHS1 being essential for redox homeostasis, proliferation, and endothelial function.
• Loss of SEPHS1 causes constitutive oxidative stress and has been linked to endothelial dysfunction, neurodevelopmental disorders, and tumor progression.
• Cancer cells depend on selenium detoxification and selenophosphate synthesis for survival, making this activity a potential therapeutic vulnerability.
• CRISPR knockout, point-mutation, knock-in, and overexpression models are powerful tools to dissect SEPHS1/SEPHS2 function in selenium metabolism and disease.
Description
Selenide, water dikinase activity (GO:0004756) is a molecular function that catalyzes the ATP-dependent synthesis of selenophosphate from hydrogen selenide and water. This reaction is the central step in the biosynthesis of selenium-containing biomolecules, providing the reactive selenium donor required for the incorporation of selenocysteine into proteins and for the synthesis of selenouridine in tRNAs. Because selenium is essential for antioxidant defense, redox homeostasis, and cellular proliferation, the enzyme responsible for this activity occupies a critical node in selenium metabolism. Researchers studying selenium biology, oxidative stress, and cancer metabolism therefore need a precise understanding of GO:0004756 and the genes that encode it. The reaction is catalyzed by selenophosphate synthetases, which in humans are encoded by SEPHS1 and SEPHS2. SEPHS1 is particularly important because it is essential for embryonic development and cell proliferation, and its deficiency leads to oxidative stress and endothelial dysfunction. Recent work has also implicated SEPHS1 in shaping an immunosuppressive tumor microenvironment, highlighting the broad relevance of this activity to disease. This article integrates the QuickGO definition with verified PubMed literature to provide a research-grade overview of GO:0004756, its mechanism, associated genes, disease links, and experimental strategies for studying it.
selenide, water dikinase activity At A Glance
| GO ID | GO:0004756 |
|---|---|
| GO term | selenide, water dikinase activity |
| Ontology | molecular_function |
| Synonym | ATP:selenide, water phosphotransferase activity; selenide,water dikinase activity; selenium donor protein activity; selenophosphate synthase activity; selenophosphate synthetase activity |
| Definition | Catalysis of the reaction: ATP + H2O + hydrogen selenide = AMP + 3 H+ + phosphate + selenophosphorate |
| Major function | Synthesis of selenophosphate, the selenium donor for selenocysteine and selenouridine biosynthesis |
| Representative genes | SEPHS1, SEPHS2 |
| Substrates | ATP, H2O, hydrogen selenide |
| Products | AMP, phosphate, selenophosphorate, H+ |
What Is GO:0004756?
GO:0004756, selenide, water dikinase activity, is defined as the catalysis of the reaction: ATP + H2O + hydrogen selenide = AMP + 3 H+ + phosphate + selenophosphorate. In other words, the enzyme transfers a phosphoryl group from ATP to selenide, producing selenophosphate, the activated selenium donor used in selenocysteine and selenouridine biosynthesis. The reaction also releases AMP, phosphate, and protons, and it requires water as a substrate. This activity is synonymous with selenophosphate synthetase activity, selenium donor protein activity, and ATP:selenide, water phosphotransferase activity.
Why Is selenide, water dikinase activity Important in Cell Biology?
GO:0004756 is important because it represents the committed step in the utilization of selenium for the synthesis of selenophosphate, without which selenocysteine-containing proteins and selenouridine-modified tRNAs cannot be produced. Selenoproteins are critical for antioxidant defense, redox signaling, and thyroid hormone metabolism, and their synthesis depends on an adequate supply of selenophosphate. Consequently, perturbations in this activity affect cell proliferation, oxidative stress responses, and survival, as demonstrated by studies showing that SEPHS1 deficiency causes constitutive oxidative stress and endothelial dysfunction. Moreover, cancer cells require selenium detoxification and selenophosphate synthesis for survival, and SEPHS1 has been implicated in shaping an immunosuppressive tumor microenvironment. Understanding GO:0004756 therefore has broad implications for cancer biology, neurodevelopment, and metabolic disease.
• Provides the essential selenium donor selenophosphate for selenocysteine incorporation into selenoproteins.
• Supports synthesis of selenouridine in tRNAs, which is required for efficient translation.
• Maintains redox homeostasis and protects cells from oxidative stress.
• Is required for endothelial cell function and vascular health.
• Plays a role in embryonic development and cell proliferation.
• Contributes to cancer cell survival through selenium detoxification.
• Modulates the tumor immune microenvironment and tumor progression.
• Has been linked to neurodevelopmental disorders through SEPHS1 mutations.
• Represents a potential target for therapeutic intervention in selenium-dependent cancers.
• Enables metabolic labeling and tracing of selenium flux in cells and tissues.
Molecular Mechanism of selenide, water dikinase activity
Substrate binding and ATP utilization
In simple terms: The enzyme grabs ATP and hydrogen selenide to start the reaction.
Selenophosphate synthetase binds ATP and hydrogen selenide (H2Se) as substrates, positioning them for phosphoryl transfer. The reaction requires water and proceeds through an intermediate in which the terminal phosphate of ATP is transferred to selenide, releasing AMP and phosphate as products. This ATP-dependent activation of selenide is the defining catalytic feature of GO:0004756.
Formation of selenophosphate
In simple terms: The enzyme attaches phosphate to selenium, creating the active selenium donor.
The product of the reaction, selenophosphate (selenophosphorate), is a high-energy selenium donor that serves as the substrate for selenocysteine synthase (SelA in bacteria, SEPHS2 in humans) and for selenouridine synthase. Selenophosphate is highly reactive and is rapidly consumed in downstream biosynthetic pathways, ensuring that selenium is channeled into selenoproteins and selenouridine.
Enzyme architecture and active site
In simple terms: The enzyme has a specific pocket where the reaction takes place.
Selenophosphate synthetases share a conserved catalytic domain that binds ATP and selenide. In humans, SEPHS1 and SEPHS2 are the two known selenophosphate synthetases, with SEPHS1 being essential for cell proliferation and redox homeostasis. Structural and biochemical studies indicate that the active site coordinates a divalent metal ion, likely Mg2+, which is required for ATP binding and catalysis.
Cofactors and metal requirements
In simple terms: The enzyme needs magnesium to work properly.
The catalytic activity of selenophosphate synthetase depends on divalent metal ions, particularly Mg2+, which stabilize ATP binding and facilitate phosphoryl transfer. The reaction also requires reducing conditions to maintain selenide in its reactive form, as oxidized selenium species are poor substrates.
Regulation of enzyme levels and activity
In simple terms: Cells control how much of this enzyme they make and how active it is.
SEPHS1 expression is regulated in response to selenium availability and oxidative stress, and its activity is influenced by the cellular redox state. SEPHS1 deficiency leads to constitutive oxidative stress, indicating that the enzyme is part of a feedback loop that maintains redox balance. In cancer cells, selenium detoxification pathways that depend on selenophosphate synthesis are upregulated to support survival under oxidative stress.
Key Genes Involved in GO:0004756 selenide, water dikinase activity
The following genes and proteins are directly or indirectly associated with selenide, water dikinase activity (GO:0004756) and its downstream pathways.
| Gene | Major Role | Research Relevance |
|---|---|---|
| SEPHS1 | Human selenophosphate synthetase 1; catalyzes selenophosphate synthesis | Essential for proliferation, redox homeostasis, and endothelial function; linked to neurodevelopmental disorders and cancer |
| SEPHS2 | Human selenophosphate synthetase 2; involved in selenocysteine synthesis | Selenoprotein biosynthesis; potential role in selenium metabolism |
| SELENOP | Selenoprotein P; selenium transport and antioxidant | Marker of selenium status; affected by selenophosphate availability |
| GPX1 | Glutathione peroxidase 1; antioxidant selenoprotein | Readout of selenoprotein synthesis and oxidative stress |
| GPX4 | Glutathione peroxidase 4; lipid peroxide detoxification | Ferroptosis regulation; dependent on selenium supply |
| TXNRD1 | Thioredoxin reductase 1; redox regulation | Selenoprotein whose synthesis depends on selenophosphate |
| TXNRD2 | Thioredoxin reductase 2; mitochondrial redox | Selenoprotein; affected by selenium metabolism |
| SELENOW | Selenoprotein W; antioxidant | Selenoprotein synthesis marker |
| SELENOF | Selenoprotein F; ER redox | Selenoprotein synthesis marker |
| SELENOK | Selenoprotein K; ER membrane | Selenoprotein synthesis marker |
| SELENOM | Selenoprotein M; ER redox | Selenoprotein synthesis marker |
| SELENON | Selenoprotein N; ER calcium regulation | Selenoprotein synthesis marker |
| SELENOS | Selenoprotein S; ER stress response | Selenoprotein synthesis marker |
| SELENOT | Selenoprotein T; ER redox | Selenoprotein synthesis marker |
| SELENOO | Selenoprotein O; mitochondrial redox | Selenoprotein synthesis marker |
| SELENOH | Selenoprotein H; nuclear redox | Selenoprotein synthesis marker |
| SELENOI | Selenoprotein I; phospholipid synthesis | Selenoprotein synthesis marker |
| SELENOV | Selenoprotein V; testis-specific | Selenoprotein synthesis marker |
How Is selenide, water dikinase activity Regulated?
Selenide, water dikinase activity is regulated at multiple levels. The expression of SEPHS1 is responsive to selenium availability and oxidative stress, and its activity is modulated by the cellular redox environment. SEPHS1 deficiency induces constitutive oxidative stress, suggesting that the enzyme is part of a feedback loop that senses and responds to reactive oxygen species. In cancer cells, selenium detoxification pathways that depend on selenophosphate synthesis are upregulated to support survival under oxidative stress, indicating that the activity is integrated with stress-response signaling. Additionally, the tumor microenvironment can influence SEPHS1 expression, as shown by its role in shaping an immunosuppressive microenvironment. Post-translational regulation of SEPHS1, including potential phosphorylation and redox modifications, may also contribute to its control, although specific mechanisms require further study.
selenide, water dikinase activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| SEPHS1 | Cancer progression and immunosuppression | SEPHS1 knockout and overexpression in cancer cell lines; syngeneic mouse models |
| SEPHS1 | Endothelial dysfunction and oxidative stress | SEPHS1 knockout endothelial cells; oxidative stress assays |
| SEPHS1 | Neurodevelopmental disorders | SEPHS1 point-mutation knock-in in neuronal cell lines or organoids |
| SEPHS2 | Selenoprotein biosynthesis defects | SEPHS2 knockout cell lines; selenoprotein expression profiling |
| GPX4 | Ferroptosis and cancer | GPX4 knockout and SEPHS1 modulation; lipid peroxidation assays |
Cancer and selenium detoxification
Cancer cells require selenium detoxification for survival, and selenophosphate synthesis is a key step in this process. SEPHS1 has been shown to shape an immunosuppressive tumor microenvironment and promote tumor progression, suggesting that targeting this activity could enhance anti-tumor immunity. The dependence of cancer cells on selenium metabolism highlights GO:0004756 as a potential therapeutic vulnerability.
Endothelial dysfunction and oxidative stress
Constitutive oxidative stress caused by SEPHS1 deficiency induces endothelial cell dysfunction, linking selenophosphate synthesis to vascular health. Loss of SEPHS1 impairs redox homeostasis and leads to increased oxidative damage, which can contribute to cardiovascular and metabolic disorders.
Neurodevelopmental disorders
Mutations in SEPHS1 have been associated with neurodevelopmental disorders, underscoring the importance of selenophosphate synthesis in brain development. The exact mechanisms are still being elucidated, but impaired selenoprotein synthesis and redox imbalance are likely contributors.
Selenoprotein-related pathologies
Because selenophosphate is required for the synthesis of all selenoproteins, defects in GO:0004756 can affect a wide range of physiological processes, including antioxidant defense, thyroid hormone metabolism, and immune function. This broad impact explains the pleiotropic effects observed in animal models and human patients with disrupted selenium metabolism.
From selenide, water dikinase activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does SEPHS1 loss affect cell proliferation and redox balance? | SEPHS1 knockout cell lines (e.g., HEK293, HeLa) |
| Does SEPHS1 deficiency alter endothelial function? | SEPHS1 knockout endothelial cells; tube formation and ROS assays |
| How does SEPHS1 contribute to tumor immune evasion? | SEPHS1 knockout tumor cells in syngeneic mouse models; immune profiling |
| What is the impact of SEPHS1 mutations on neurodevelopment? | SEPHS1 point-mutation knock-in in neuronal cell lines or iPSC-derived neurons |
| Can SEPHS1 overexpression drive selenium detoxification? | SEPHS1 overexpression in cancer cell lines; selenium sensitivity assays |
| What is the subcellular localization of SEPHS1? | SEPHS1 tagged knock-in (e.g., GFP) in cell lines; imaging |
How to Study the selenide, water dikinase activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Radioactive enzyme assay | Selenophosphate synthesis rate | Kinetic characterization of SEPHS1/SEPHS2 |
| RNA-seq | Transcriptional changes upon SEPHS1 perturbation | Identifying selenium-responsive pathways |
| Proteomics | Selenoprotein expression levels | Validating downstream effects of selenophosphate synthesis |
| ROS detection assays | Oxidative stress levels | Assessing SEPHS1 deficiency phenotypes |
| Lipid peroxidation assay | Ferroptosis sensitivity | Linking selenium metabolism to cell death |
| CRISPR knockout screens | Gene dependencies and synthetic lethality | Identifying modifiers of selenium sensitivity |
| Immunofluorescence | Subcellular localization of SEPHS1 | Determining organelle-specific functions |
| Seahorse metabolic analysis | Mitochondrial respiration and glycolysis | Evaluating metabolic reprogramming in SEPHS1 mutants |
Biochemical assays for selenophosphate synthesis
Direct measurement of selenide, water dikinase activity can be performed using radiolabeled ATP or selenide, followed by chromatographic separation of products. These assays are useful for validating enzyme kinetics and inhibitor studies.
Gene expression and proteomics
RNA-seq and quantitative proteomics can assess the impact of SEPHS1/SEPHS2 perturbations on selenoprotein expression and global gene expression. Western blotting for selenoproteins such as GPX1 and TXNRD1 provides a readout of selenophosphate availability.
Redox and oxidative stress measurements
ROS levels, glutathione ratios, and lipid peroxidation can be measured to evaluate the consequences of altered selenophosphate synthesis. These assays are particularly relevant for studying endothelial dysfunction and ferroptosis.
CRISPR-based functional genomics
CRISPR knockout screens can identify genes that modulate sensitivity to selenium or selenophosphate depletion, revealing synthetic lethal interactions. Library screening and bioinformatics analyses can uncover pathways that compensate for loss of GO:0004756 activity.
How CRISPR Can Be Used to Study GO:0004756 selenide, water dikinase activity
Knockout
CRISPR knockout of SEPHS1 or SEPHS2 eliminates selenide, water dikinase activity, leading to impaired selenoprotein synthesis and increased oxidative stress. Knockout models are essential for studying the essentiality of this activity in proliferation, endothelial function, and tumor growth.
Point Mutation
Point mutations in the catalytic domain of SEPHS1 can be introduced to dissect specific residues required for ATP binding or selenide coordination. Such models help distinguish loss-of-function from hypomorphic alleles and can mimic patient mutations associated with neurodevelopmental disorders.
Knock-in
Knock-in of tagged SEPHS1 (e.g., GFP or HA) allows visualization and immunoprecipitation of the enzyme to study its localization and interaction partners. Knock-in of disease-associated mutations can model human pathology in cell lines or organoids.
Overexpression
Overexpression of SEPHS1 or SEPHS2 can enhance selenophosphate synthesis and selenium detoxification, protecting cells from oxidative stress. Overexpression models are useful for studying the contribution of this activity to cancer cell survival and immune evasion.
How EDITGENE Supports selenide, water dikinase activity Research
Researchers studying selenide, water dikinase activity-related genes often need to determine whether a candidate gene is causally involved in selenium metabolism, redox homeostasis, or disease progression. EDITGENE provides a comprehensive suite of CRISPR-based services to generate precisely engineered cell models, enabling rigorous functional validation of GO:0004756 and its associated genes.
Contact EDITGENE today to design your custom CRISPR model for selenide, water dikinase activity research.
Frequently Asked Questions About selenide, water dikinase activity
What is selenide, water dikinase activity?
Selenide, water dikinase activity (GO:0004756) is the enzyme activity that catalyzes the ATP-dependent conversion of hydrogen selenide to selenophosphate, the selenium donor for selenocysteine and selenouridine biosynthesis.
What genes encode selenide, water dikinase activity?
In humans, the principal genes are SEPHS1 and SEPHS2, which encode selenophosphate synthetases.
What is the reaction catalyzed by GO:0004756?
The reaction is: ATP + H2O + hydrogen selenide = AMP + 3 H+ + phosphate + selenophosphorate.
Why is selenophosphate synthetase important for cells?
It provides the essential selenium donor for selenoprotein synthesis, which is required for antioxidant defense, redox homeostasis, and cell proliferation.
How is SEPHS1 linked to cancer?
SEPHS1 supports selenium detoxification and shapes an immunosuppressive tumor microenvironment, promoting tumor progression.
What happens when SEPHS1 is lost?
SEPHS1 deficiency causes constitutive oxidative stress, endothelial dysfunction, and impaired proliferation.
Is SEPHS1 associated with neurodevelopmental disorders?
Yes, mutations in SEPHS1 have been linked to neurodevelopmental disorders.
What research methods are used to study selenide, water dikinase activity?
Common methods include radioactive enzyme assays, RNA-seq, proteomics, ROS detection, and CRISPR screens.
Can CRISPR be used to study GO:0004756?
Yes, CRISPR knockout, point mutation, knock-in, and overexpression models are widely used to dissect the function of SEPHS1 and SEPHS2.
What are the synonyms for selenide, water dikinase activity?
Synonyms include selenophosphate synthetase activity, selenophosphate synthase activity, selenium donor protein activity, and ATP:selenide, water phosphotransferase activity.
Conclusion
Selenide, water dikinase activity (GO:0004756) is a fundamental molecular function that supplies the selenium donor selenophosphate for selenoprotein and selenouridine biosynthesis. Its importance spans redox homeostasis, cell proliferation, endothelial function, neurodevelopment, and cancer progression. By leveraging CRISPR-based models and multi-omics approaches, researchers can dissect the precise roles of SEPHS1 and SEPHS2 in health and disease, paving the way for new therapeutic strategies targeting selenium metabolism.
References
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- 4. Liu Y et al.. 2025. Dissecting the role of SEPHS1 in shaping an immunosuppressive microenvironment to promote tumor progression.. Cancer Immunol Immunother 75(1):29 PMID: 41441975
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- 6. Hoffman KS et al.. 2023. Recoding UAG to selenocysteine in Saccharomyces cerevisiae.. RNA 29(9):1400-1410 PMID: 37279998
- 7. Ahmed Mohamed Z et al.. 2024. SEPHS1 Gene: A new master key for neurodevelopmental disorders.. Clin Chim Acta 562:119844 PMID: 38960024
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