GO:0008431 vitamin E binding: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0008431 vitamin E binding is a molecular function describing the selective, non-covalent binding of tocopherols and tocotrienols, with alpha-tocopherol as the most biologically active form in humans.
• Vitamin E binding proteins include afamin, the 67 kDa laminin receptor, tocopherol transfer protein (TTPA), and other lipid-binding proteins that determine vitamin E transport, cellular uptake, and tissue distribution.
• Vitamin E binding is not merely passive storage; it can modulate signaling pathways such as diacylglycerol kinase activation and immune checkpoint regulation via SHP1.
• Defects in vitamin E binding and transport are linked to vitamin E deficiency, ataxia with vitamin E deficiency (AVED), and altered susceptibility to cancer and infection.
• CRISPR knockout, point-mutation, knock-in, and overexpression models are essential to dissect the causal roles of vitamin E binding proteins in health and disease.
• Studying GO:0008431 requires integrated approaches including ligand-binding assays, structural biology, transcriptomics, proteomics, and functional rescue experiments.
Description
Vitamin E binding (GO:0008431) is a molecular function that describes the specific interaction of proteins with vitamin E compounds, primarily tocopherols and tocotrienols. Vitamin E is a collective term for eight structurally related lipid-soluble antioxidants, with alpha-tocopherol being the most active form in humans. The biological actions of vitamin E depend on its binding to proteins that mediate its absorption, transport, cellular uptake, and subcellular localization. Understanding this binding function is therefore central to explaining how vitamin E exerts its antioxidant and non-antioxidant effects in health and disease. This article provides a research-grade overview of GO:0008431, integrating the QuickGO definition with verified PubMed literature to support researchers studying vitamin E biology, gene function, and CRISPR-based disease modeling.
vitamin E binding At A Glance
| GO ID | GO:0008431 |
|---|---|
| GO term | vitamin E binding |
| Ontology | molecular_function |
| Synonym | alpha-tocopherol binding; tocopherol binding |
| Definition | Binding to a vitamin E, tocopherol, which includes a series of eight structurally similar compounds. Alpha-tocopherol is the most active form in humans and is a powerful biological antioxidant. |
| Major function | Selective non-covalent binding of tocopherols and tocotrienols, influencing transport, cellular uptake, and signaling. |
| Representative proteins | Afamin, 67 kDa laminin receptor, tocopherol transfer protein (TTPA), and other lipid-binding proteins. |
| Associated processes | Vitamin E transport, antioxidant defense, immune modulation, and cell signaling. |
| Disease relevance | Vitamin E deficiency, ataxia with vitamin E deficiency, cancer immunotherapy response, and bacterial antibiotic sensitivity. |
What Is GO:0008431?
GO:0008431 vitamin E binding is defined as the selective, non-covalent interaction of a protein or biomolecule with a vitamin E compound, which includes tocopherols and tocotrienols. The term encompasses binding to alpha-tocopherol, the most biologically active form in humans, as well as other stereoisomers and analogs. This function is distinct from enzymatic antioxidant activity because it describes the physical association with vitamin E rather than the chemical scavenging of radicals. Proteins annotated with this function often act as transporters, carriers, or signaling modulators that determine the bioavailability and cellular effects of vitamin E.
Why Is vitamin E binding Important in Cell Biology?
GO:0008431 is important because vitamin E binding proteins control the fate and function of vitamin E in the body, from intestinal absorption to tissue delivery and intracellular signaling. Dysregulation of these binding interactions can lead to vitamin E deficiency, neurological dysfunction, and altered responses to oxidative stress and immunotherapy. Moreover, vitamin E binding to specific proteins such as the 67 kDa laminin receptor can activate signaling cascades, demonstrating that this molecular function has roles beyond antioxidant storage. Understanding these interactions at the gene and protein level is essential for developing targeted therapies and for interpreting genetic variants that affect vitamin E status.
• Vitamin E binding proteins determine the bioavailability and tissue distribution of alpha-tocopherol, the most active vitamin E form.
• Mutations in the tocopherol transfer protein (TTPA) cause ataxia with vitamin E deficiency, highlighting the clinical importance of vitamin E binding and transport.
• Vitamin E binding to the 67 kDa laminin receptor activates diacylglycerol kinase, linking this function to cell signaling.
• Vitamin E enhances cancer immunotherapy by targeting the checkpoint SHP1 in dendritic cells, a process that may involve binding interactions.
• Vitamin E can increase antimicrobial sensitivity by inhibiting bacterial lipocalin antibiotic binding, showing cross-kingdom relevance.
• Afamin in human plasma binds vitamin E, serving as a transport protein and a potential biomarker.
• Different stereoisomers of vitamin E exhibit distinct binding affinities and biological activities, affecting research reproducibility.
• CRISPR-based models of vitamin E binding genes can clarify causal roles in disease and guide therapeutic development.
Molecular Mechanism of vitamin E binding
Ligand recognition and binding specificity
In simple terms: Proteins that bind vitamin E have pockets that fit tocopherol molecules, and they can distinguish between different forms of vitamin E.
Vitamin E binding proteins recognize the chromanol ring and phytyl tail of tocopherols, with alpha-tocopherol being the most efficiently bound form in humans. The binding specificity is determined by the shape and chemical properties of the binding pocket, which can discriminate among the eight structurally similar compounds. For example, afamin in human plasma binds vitamin E with high affinity, facilitating its transport. The 67 kDa laminin receptor also binds vitamin E, and this interaction is required for downstream signaling.
Transport and cellular uptake
In simple terms: After binding, proteins carry vitamin E through the blood and into cells where it is needed.
Vitamin E is absorbed in the intestine and secreted into plasma, where it associates with lipoproteins and specific binding proteins such as afamin. The tocopherol transfer protein (TTPA) in the liver preferentially binds alpha-tocopherol and facilitates its incorporation into very low-density lipoproteins for distribution to tissues. This transport system ensures that the most active form of vitamin E reaches target organs, and defects in TTPA lead to vitamin E deficiency.
Intracellular localization and signaling
In simple terms: Inside cells, vitamin E binding proteins can deliver vitamin E to specific compartments and trigger signals.
Vitamin E binding is not limited to transport; it can also modulate intracellular signaling. The 67 kDa laminin receptor binds vitamin E and activates diacylglycerol kinase, which converts diacylglycerol to phosphatidic acid and influences cell proliferation and survival. In dendritic cells, vitamin E binding to SHP1 may reinvigorate immune responses against cancer. These examples show that vitamin E binding proteins can act as signaling modulators beyond their antioxidant roles.
Antioxidant and non-antioxidant functions
In simple terms: Vitamin E can neutralize harmful molecules, but when bound to proteins it can also have other jobs.
Alpha-tocopherol is a powerful biological antioxidant that scavenges lipid peroxyl radicals, protecting membranes from oxidative damage. However, vitamin E binding proteins can also mediate non-antioxidant functions, such as regulation of enzyme activity and gene expression. The balance between antioxidant and non-antioxidant effects depends on the specific binding protein and cellular context.
Regulation of vitamin E binding
In simple terms: The amount of vitamin E binding proteins in a cell can change, affecting how much vitamin E is bound and used.
The expression and activity of vitamin E binding proteins are regulated at multiple levels. TTPA expression is influenced by vitamin E status and genetic variants. Afamin levels in plasma can vary with physiological and pathological conditions. Additionally, the binding affinity of proteins like the 67 kDa laminin receptor may be modulated by post-translational modifications or interacting partners. These regulatory mechanisms ensure that vitamin E is distributed appropriately under different conditions.
Key Genes Involved in GO:0008431 vitamin E binding
The following genes encode proteins that bind vitamin E or regulate its transport and function, as supported by published literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| TTPA | Tocopherol transfer protein; binds alpha-tocopherol and facilitates its secretion into lipoproteins | Mutations cause ataxia with vitamin E deficiency; key for vitamin E transport studies. |
| AFM | Afamin; plasma vitamin E-binding protein | Biomarker for vitamin E status; involved in transport and bioavailability. |
| RPSA | 67 kDa laminin receptor; binds vitamin E and activates diacylglycerol kinase | Mediates non-antioxidant signaling; target for cancer and signaling research. |
| PTPN6 | SHP1; phosphatase targeted by vitamin E in dendritic cells | Enhances cancer immunotherapy; potential target for immune modulation. |
| APOA1 | Apolipoprotein A1; component of HDL that carries vitamin E | Influences vitamin E distribution in plasma. |
| APOB | Apolipoprotein B; component of LDL that carries vitamin E | Affects vitamin E delivery to tissues. |
| ABCA1 | ATP-binding cassette transporter A1; involved in HDL biogenesis and vitamin E efflux | Modulates vitamin E cellular efflux and plasma levels. |
| SCARB1 | Scavenger receptor class B member 1; mediates HDL uptake and vitamin E delivery | Affects cellular vitamin E uptake. |
| CYP4F2 | Cytochrome P450 family 4 subfamily F member 2; metabolizes vitamin E | Influences vitamin E catabolism and status. |
| TTPA | Tocopherol transfer protein; also known as alpha-tocopherol transfer protein | Central to vitamin E homeostasis; studied in AVED models. |
| LRP1 | LDL receptor-related protein 1; may mediate vitamin E uptake | Potential role in vitamin E transport. |
| NPC1L1 | Niemann-Pick C1-like 1; intestinal cholesterol and vitamin E absorption | Determines vitamin E absorption efficiency. |
| ABCG1 | ATP-binding cassette transporter G1; involved in vitamin E efflux | Regulates cellular vitamin E levels. |
| PLA2G7 | Lipoprotein-associated phospholipase A2; may affect vitamin E distribution | Linked to oxidative stress and inflammation. |
| SOD1 | Superoxide dismutase 1; antioxidant enzyme that may interact with vitamin E | Studied in neurodegeneration and oxidative stress. |
| CAT | Catalase; antioxidant enzyme | Indirectly related to vitamin E antioxidant network. |
| GPX1 | Glutathione peroxidase 1; antioxidant enzyme | Works with vitamin E to reduce oxidative stress. |
| NFE2L2 | Nrf2; transcription factor regulating antioxidant response | May influence vitamin E binding protein expression. |
How Is vitamin E binding Regulated?
Vitamin E binding is regulated by the expression levels and post-translational modifications of binding proteins, as well as by the availability of vitamin E stereoisomers. TTPA expression is influenced by vitamin E status and genetic variants, and its activity determines plasma alpha-tocopherol concentrations. Afamin levels in plasma can change under different physiological conditions, affecting vitamin E transport. Additionally, the binding of vitamin E to the 67 kDa laminin receptor can be modulated by the cellular redox state and interacting proteins. These regulatory layers ensure that vitamin E is distributed and utilized appropriately, and their disruption can lead to deficiency or altered signaling.
vitamin E binding and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| TTPA | Ataxia with vitamin E deficiency (AVED) | Knockout mouse or patient-derived iPSCs with TTPA mutations. |
| PTPN6 | Cancer immunotherapy response | Knockout or point-mutation in dendritic cells to study SHP1-vitamin E interaction. |
| RPSA | Cell signaling and cancer | Overexpression or knockout of 67 kDa laminin receptor in cancer cell lines. |
| AFM | Vitamin E transport and biomarker | Knockout or tagged knock-in in hepatocytes to track afamin secretion. |
| CYP4F2 | Vitamin E metabolism and status | Point mutation or knockout to assess vitamin E catabolism. |
Vitamin E deficiency and ataxia with vitamin E deficiency (AVED)
Mutations in the TTPA gene impair the binding and transport of alpha-tocopherol, leading to vitamin E deficiency and a progressive neurological disorder known as ataxia with vitamin E deficiency. Patients present with ataxia, neuropathy, and other neurological symptoms that can be alleviated by high-dose vitamin E supplementation. This highlights the critical role of vitamin E binding proteins in maintaining normal neurological function.
Cancer and immunotherapy
Vitamin E binding to SHP1 in dendritic cells can reinvigorate antitumor immune responses, enhancing the efficacy of cancer immunotherapy. This suggests that vitamin E binding proteins are potential targets for improving immune checkpoint blockade. Additionally, the 67 kDa laminin receptor, which binds vitamin E, is involved in cell signaling pathways that affect tumor growth and survival.
Infectious disease and antimicrobial sensitivity
Vitamin E can increase antimicrobial sensitivity by inhibiting bacterial lipocalin antibiotic binding, indicating that vitamin E binding interactions can affect bacterial resistance mechanisms. This cross-kingdom relevance underscores the broader biological importance of vitamin E binding beyond human physiology.
Oxidative stress and chronic diseases
Vitamin E binding proteins contribute to the antioxidant defense system, and their dysfunction may exacerbate oxidative stress in chronic diseases such as cardiovascular disease and neurodegeneration. However, clinical trials of vitamin E supplementation have shown mixed results, possibly due to differences in binding protein status and stereoisomer specificity.
From vitamin E binding-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does TTPA binding to alpha-tocopherol prevent neurodegeneration? | TTPA knockout mouse or knock-in of patient mutations. |
| How does vitamin E binding to SHP1 affect dendritic cell function? | PTPN6 knockout or point-mutation in dendritic cells. |
| What is the role of afamin in vitamin E transport? | AFM knockout or tagged knock-in in liver cells. |
| Does the 67 kDa laminin receptor mediate vitamin E signaling? | RPSA knockout or overexpression in cancer cell lines. |
| How do vitamin E stereoisomers differentially bind to proteins? | Point mutations in binding pockets of TTPA or afamin. |
| Can vitamin E binding proteins be targeted for immunotherapy? | Knock-in of human SHP1 variants into mouse models. |
How to Study the vitamin E binding Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Isothermal titration calorimetry | Binding affinity and thermodynamics | Characterize vitamin E binding to purified proteins. |
| Surface plasmon resonance | Real-time binding kinetics | Screen for vitamin E analogs or inhibitors. |
| X-ray crystallography | Three-dimensional structure of binding pocket | Determine molecular basis of stereoisomer specificity. |
| RNA-seq | Gene expression changes | Identify pathways regulated by vitamin E binding. |
| Proteomics | Protein abundance and interactions | Discover novel vitamin E binding proteins. |
| CRISPR knockout | Loss-of-function phenotypes | Test causal role of candidate genes in vitamin E binding. |
| CRISPR knock-in | Precise mutation or tag insertion | Model patient mutations or track protein localization. |
| Flow cytometry | Cell surface and intracellular markers | Assess immune cell activation by vitamin E. |
Ligand-binding assays
Direct binding assays such as isothermal titration calorimetry, surface plasmon resonance, and fluorescence polarization can measure the affinity and specificity of vitamin E binding to proteins like afamin and TTPA. These methods are essential for characterizing the molecular function GO:0008431 and for screening for inhibitors or competitors.
Structural biology
X-ray crystallography and cryo-electron microscopy can reveal the atomic details of vitamin E binding pockets, as demonstrated for afamin and other lipid-binding proteins. Structural insights guide the design of point mutations to test binding specificity and function.
Transcriptomics and proteomics
RNA-seq and mass spectrometry-based proteomics can identify genes and proteins whose expression changes upon vitamin E binding or deficiency. These approaches help uncover downstream signaling pathways and regulatory networks associated with GO:0008431.
Functional assays in cell and animal models
Cell-based assays measuring oxidative stress, immune cell activation, and signaling can assess the functional consequences of vitamin E binding. Animal models with genetic modifications in vitamin E binding proteins provide in vivo validation of disease relevance.
How CRISPR Can Be Used to Study GO:0008431 vitamin E binding
Knockout
CRISPR knockout of genes encoding vitamin E binding proteins, such as TTPA or RPSA, can reveal their essential roles in vitamin E transport and signaling. Knockout cell lines and animal models are valuable for studying loss-of-function phenotypes and for validating drug targets.
Point Mutation
Introducing point mutations into the binding pocket of vitamin E binding proteins can test the specificity of ligand recognition and the functional consequences of patient variants. For example, mutations in TTPA that impair alpha-tocopherol binding cause AVED.
Knock-in
Knock-in of tagged or humanized versions of vitamin E binding proteins allows tracking of protein localization and interaction with vitamin E in vivo. This approach is useful for studying dynamic transport and signaling processes.
Overexpression
Overexpression of vitamin E binding proteins can amplify binding capacity and downstream signaling, enabling researchers to study gain-of-function effects and to screen for modulators. Overexpression models are particularly useful for identifying non-antioxidant functions of vitamin E.
How EDITGENE Supports vitamin E binding Research
Researchers studying vitamin E binding-related genes often need to determine whether a candidate gene is causally involved in vitamin E transport, signaling, or disease. EDITGENE provides comprehensive CRISPR gene editing services to create knockout, point-mutation, knock-in, and overexpression cell models, as well as CRISPR library screening and bioinformatics support, enabling rigorous functional studies of GO:0008431.
Contact EDITGENE today to design your custom CRISPR model for vitamin E binding research.
Frequently Asked Questions About vitamin E binding
What is GO:0008431 vitamin E binding?
GO:0008431 is a Gene Ontology molecular function term describing the selective binding of proteins to vitamin E compounds, including tocopherols and tocotrienols, with alpha-tocopherol being the most active form in humans.
What genes are involved in vitamin E binding?
Key genes include TTPA, AFM, RPSA, and PTPN6, which encode proteins that bind vitamin E or mediate its transport and signaling.
How is vitamin E binding studied?
Researchers use ligand-binding assays, structural biology, transcriptomics, proteomics, and CRISPR-based models to study vitamin E binding.
What diseases are linked to vitamin E binding?
Mutations in TTPA cause ataxia with vitamin E deficiency, and vitamin E binding to SHP1 affects cancer immunotherapy responses.
What is the role of TTPA in vitamin E binding?
TTPA binds alpha-tocopherol and facilitates its secretion into lipoproteins, and its dysfunction leads to vitamin E deficiency.
Can CRISPR be used to study vitamin E binding?
Yes, CRISPR knockout, point mutation, knock-in, and overexpression models are powerful tools to dissect the causal roles of vitamin E binding genes.
What is the most active form of vitamin E in humans?
Alpha-tocopherol is the most active form of vitamin E in humans and is a powerful biological antioxidant.
How does vitamin E binding affect cell signaling?
Vitamin E binding to the 67 kDa laminin receptor activates diacylglycerol kinase, and binding to SHP1 modulates immune checkpoint signaling.
What are the synonyms for GO:0008431?
The synonyms are alpha-tocopherol binding and tocopherol binding.
Why is vitamin E binding important for nutrition?
Vitamin E binding proteins determine the absorption, transport, and tissue delivery of vitamin E, affecting its bioavailability and biological effects.
Conclusion
GO:0008431 vitamin E binding is a fundamental molecular function that governs the transport, cellular uptake, and signaling of vitamin E compounds. Proteins such as TTPA, afamin, and the 67 kDa laminin receptor mediate these interactions, with critical implications for neurological health, cancer immunotherapy, and infectious disease. Continued research using CRISPR-based models and integrated omics approaches will further elucidate the mechanisms and therapeutic potential of vitamin E binding.
References
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- 3. Traber MG. 2005. Vitamin E regulation.. Curr Opin Gastroenterol 21(2):223-7 PMID: 15711217
- 4. Hayashi D et al.. 2022. Vitamin E functions by association with a novel binding site on the 67 kDa laminin receptor activating diacylglycerol kinase.. J Nutr Biochem 110:109129 PMID: 35977663
- 5. Naguib MM et al.. 2018. Vitamin E Increases Antimicrobial Sensitivity by Inhibiting Bacterial Lipocalin Antibiotic Binding.. mSphere 3(6) PMID: 30541778
- 6. Eggersdorfer M et al.. 2024. Vitamin E: Not only a single stereoisomer.. Free Radic Biol Med 215:106-111 PMID: 38401827
- 7. Kaempf-Rotzoll DE et al.. 2003. Vitamin E and transfer proteins.. Curr Opin Lipidol 14(3):249-54 PMID: 12840655
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