GO:0000822 inositol hexakisphosphate binding: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0000822 (inositol hexakisphosphate binding) is a molecular function defined as binding to inositol hexakisphosphate (InsP6, phytic acid), a highly phosphorylated inositol derivative [2,5].
• InsP6 binding proteins include ion channels, ubiquitin ligases, DNA repair factors, and plant immune receptors, linking the metabolite to diverse cellular processes [1,7,8].
• The interaction is often electrostatic, with InsP6 acting as a structural cofactor or allosteric regulator [3,4,8].
• Dysregulation of InsP6 binding contributes to cancer, neurodegeneration, and immune disorders, making it a potential therapeutic target [3,7,8].
• CRISPR-based models (knockout, point mutation, knock-in, overexpression) enable functional dissection of InsP6-binding proteins in disease contexts.
• EDITGENE provides end-to-end services for generating and screening such models, accelerating research on InsP6-mediated biology.
Description
Inositol hexakisphosphate (InsP6), also known as phytic acid, is the most abundant inositol phosphate in eukaryotic cells and serves as a precursor for higher inositol pyrophosphates. The binding of InsP6 to specific proteins, defined by the Gene Ontology term GO:0000822 (inositol hexakisphosphate binding), is a molecular function that underpins a wide range of cellular activities, from auxin perception in plants to DNA repair and immune signaling in animals [1,7,8]. This article synthesizes authoritative QuickGO data and verified PubMed literature to provide a comprehensive overview of the term, its mechanisms, associated genes, and experimental approaches for studying it.
inositol hexakisphosphate binding At A Glance
| GO ID | GO:0000822 |
|---|---|
| GO term | inositol hexakisphosphate binding |
| Ontology | molecular_function |
| Synonym | InsP6 binding, IP6 binding |
| Major function | Binding to inositol hexakisphosphate, often acting as a cofactor or allosteric regulator |
| Definition source | QuickGO |
| Related metabolites | Inositol hexakisphosphate (InsP6), phytic acid |
| Common protein domains | Not applicable; binding is mediated by clusters of basic residues |
What Is GO:0000822?
GO:0000822, inositol hexakisphosphate binding, is defined as the binding to inositol hexakisphosphate, a molecule with six phosphate groups attached to an inositol ring. This binding event typically involves electrostatic interactions between the negatively charged phosphate groups of InsP6 and positively charged residues on the target protein, and it can modulate protein stability, localization, or activity [2,5,7].
Why Is inositol hexakisphosphate binding Important in Cell Biology?
Understanding inositol hexakisphosphate binding is crucial because InsP6 is a central metabolite in cellular signaling, and its protein partners are implicated in fundamental processes such as gene regulation, DNA repair, and immune responses [3,7,8]. Moreover, InsP6-binding proteins are linked to human diseases including cancer and neurodegeneration, and they represent potential targets for therapeutic intervention [3,7,8].
• InsP6 binding regulates the activity of the TIR1 auxin receptor, a key component of plant hormone signaling.
• It is required for the function of the Integrator complex, which controls RNA polymerase II transcription and snRNA processing.
• InsP6 binds to the Ku70/80 heterodimer, a critical factor in non-homologous end joining DNA repair.
• The binding of InsP6 to plant NLR immune receptors modulates their oligomerization and autoinhibition.
• InsP6 binding sites have been identified in rat heart and brain membranes, suggesting roles in cardiovascular and neurological functions.
• In adrenal chromaffin cells, InsP6 binding affects calcium-dependent catecholamine release.
• Dysregulation of InsP6 metabolism is associated with cancer progression and neurodegenerative disorders [3,7,8].
• Proteome-wide studies have quantified InsP6-protein interactions, revealing new binding partners and regulatory networks.
• The binding of InsP6 to XPR1 reveals a mechanism for phosphate export, linking InsP6 to phosphate homeostasis.
Molecular Mechanism of inositol hexakisphosphate binding
Electrostatic Interactions Drive InsP6 Binding
In simple terms: InsP6 sticks to proteins because it has many negative charges that attract positive charges on the protein.
Inositol hexakisphosphate is a highly negatively charged molecule due to its six phosphate groups. It binds to proteins primarily through electrostatic interactions with clusters of basic amino acids such as arginine and lysine. For example, the binding of InsP6 to the TIR1 auxin receptor involves a positively charged pocket that accommodates the phosphate groups, facilitating auxin perception. Similarly, InsP6 binding to Ku70/80 is mediated by electrostatic interactions that are essential for DNA repair.
InsP6 as a Structural Cofactor
In simple terms: Sometimes InsP6 acts like a scaffold, helping proteins fold or assemble into functional complexes.
In several proteins, InsP6 serves as a structural cofactor that stabilizes protein conformations or promotes oligomerization. For instance, the Integrator complex requires InsP6 for its assembly and function in RNA processing. In plant NLR immune receptors, InsP6 binding is involved in oligomerization-mediated autoinhibition, where the metabolite helps maintain an inactive state that can be relieved upon activation. These examples highlight the role of InsP6 beyond simple binding, acting as a molecular glue.
Allosteric Regulation by InsP6
In simple terms: InsP6 can change a protein's shape from a distance, turning its activity on or off.
InsP6 binding can induce conformational changes that allosterically regulate protein function. For example, in the XPR1 phosphate exporter, InsP6 binding is thought to modulate the protein's activity in phosphate export, revealing a link between InsP6 and phosphate homeostasis. Similarly, the binding of InsP6 to adrenal chromaffin cell membranes affects calcium-dependent catecholamine release, suggesting an allosteric role in secretion.
Specificity and Affinity of InsP6 Binding
In simple terms: Proteins can distinguish InsP6 from other similar molecules and bind it tightly.
InsP6 binding sites exhibit specificity for the fully phosphorylated inositol ring, discriminating against lower inositol phosphates. Binding affinities can range from low micromolar to nanomolar, as observed in rat heart and brain membranes. Proteome-wide quantification has revealed that some proteins bind InsP6 with high specificity, while others interact with inositol pyrophosphates, indicating a nuanced regulatory network.
Regulation of InsP6 Binding by Cellular Levels
In simple terms: The amount of InsP6 in the cell controls how much binding occurs.
Cellular levels of InsP6 fluctuate in response to metabolic and signaling cues, thereby regulating the extent of InsP6-protein interactions. For example, in adrenal chromaffin cells, InsP6 binding and its effects on catecholamine release are dependent on calcium and likely on InsP6 availability. Additionally, the synthesis of InsP6 is tightly regulated, and changes in its concentration can impact processes such as DNA repair and immune signaling [7,8].
Key Genes Involved in GO:0000822 inositol hexakisphosphate binding
The following genes encode proteins that have been experimentally shown to bind inositol hexakisphosphate, based on verified PubMed literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| TIR1 | Auxin receptor; InsP6 binding required for auxin perception | Plant hormone signaling; structural studies of InsP6 binding |
| XPR1 | Phosphate exporter; InsP6 binding modulates export activity | Phosphate homeostasis; structural basis of InsP6 binding |
| KU70 | DNA repair protein; binds InsP6 | Non-homologous end joining; cancer and aging research |
| KU80 | DNA repair protein; forms heterodimer with KU70 | DNA repair mechanisms; InsP6 binding affects complex stability |
| INTS (Integrator complex subunits) | RNA processing; InsP6 required for function | Transcription and RNA processing; InsP6 as cofactor |
| NLR (plant immune receptors) | Immune signaling; InsP6 binding regulates oligomerization | Plant immunity; autoinhibition mechanisms |
| Chromaffin cell membrane proteins | Catecholamine release; InsP6 binding sites | Neurosecretion; calcium-dependent exocytosis |
| Heart and brain membrane proteins | Unidentified InsP6 binding sites | Cardiovascular and neurological functions |
| InsP6-binding proteins (proteome-wide) | Various; quantified interactions | Systems-level analysis of InsP6 interactions |
How Is inositol hexakisphosphate binding Regulated?
The binding of inositol hexakisphosphate to proteins is regulated by the cellular concentration of InsP6, which in turn is controlled by enzymes of inositol phosphate metabolism. For example, the levels of InsP6 can be modulated by inositol polyphosphate kinases and phosphatases, affecting interactions with proteins such as the Integrator complex and plant NLRs [3,8]. Additionally, post-translational modifications of target proteins, such as phosphorylation, can influence their affinity for InsP6. However, detailed regulatory mechanisms remain an active area of research.
inositol hexakisphosphate binding and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| KU70/KU80 | Cancer, DNA repair deficiency | Knockout cell lines, point mutations in InsP6-binding residues |
| Integrator complex | Immune disorders, developmental defects | Knock-in of InsP6-binding mutations, overexpression |
| Plant NLRs | Autoimmune responses in plants | Point mutations, knockout in plant models |
| XPR1 | Phosphate homeostasis disorders | Knockout and knock-in in cell lines |
| TIR1 | Plant growth and development | Knockout and point mutation in Arabidopsis |
Cancer
InsP6 binding proteins such as Ku70/80 are critical for DNA double-strand break repair, and their dysfunction can lead to genomic instability and cancer. Additionally, InsP6 has been shown to inhibit tumor growth in various models, partly through its interactions with proteins involved in cell cycle regulation and apoptosis. The binding of InsP6 to the TIR1 auxin receptor in plants is not directly linked to human cancer, but the principle of InsP6 as a regulatory molecule is conserved.
Neurodegeneration
InsP6 binding sites are present in brain membranes, and InsP6 has been implicated in neuronal signaling and calcium homeostasis. Dysregulation of InsP6 metabolism has been associated with neurodegenerative conditions such as Alzheimer's disease, although the exact role of InsP6 binding proteins in these diseases requires further investigation. The effects of InsP6 on catecholamine release from adrenal chromaffin cells suggest a broader role in neurotransmitter release.
Immune Disorders
In plants, InsP6 binding to NLR immune receptors regulates their activity, and mutations affecting this binding can lead to autoimmune responses. In humans, the Integrator complex, which requires InsP6 for function, is involved in RNA processing and its dysregulation has been linked to immune disorders and developmental defects. These findings highlight the importance of InsP6 binding in immune regulation across species.
From inositol hexakisphosphate binding-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of InsP6 binding affect protein function? | Knockout of the binding protein or point mutation of key basic residues |
| How does a disease-associated mutation alter InsP6 binding? | Point mutation knock-in using CRISPR |
| Can InsP6 binding be visualized in live cells? | Tagged knock-in with fluorescent protein |
| What are the downstream effects of InsP6 binding? | Overexpression of wild-type vs. binding-deficient mutant |
| Which genes are regulated by InsP6-binding proteins? | Knockout followed by RNA-seq |
| Can we identify new InsP6-binding proteins? | Proteome-wide pull-down with InsP6 probes |
How to Study the inositol hexakisphosphate binding Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Radioligand binding | Affinity and number of binding sites | Characterization of InsP6 binding in tissues |
| Isothermal titration calorimetry | Binding affinity and thermodynamics | Quantification of InsP6-protein interactions |
| X-ray crystallography | 3D structure of protein-InsP6 complex | Structural basis of binding [1,4] |
| Cryo-EM | Structure of large complexes with InsP6 | Integrator and NLR complexes [3,8] |
| Mass spectrometry | Identification of InsP6-binding proteins | Proteome-wide screening |
| RNA-seq | Transcriptional changes upon InsP6 binding perturbation | Knockout or mutant cell lines |
| CRISPR screening | Genes required for InsP6-mediated processes | Functional genomics |
| Live-cell imaging | Localization and dynamics of InsP6-binding proteins | Tagged knock-in cell lines |
Biochemical Binding Assays
Radioligand binding assays using tritiated InsP6 have been used to characterize binding sites in rat heart and brain membranes. Similarly, filter-binding assays and isothermal titration calorimetry can measure affinity and specificity. These methods are foundational for validating InsP6-protein interactions.
Structural Biology
X-ray crystallography and cryo-electron microscopy have revealed the structural basis of InsP6 binding to proteins such as TIR1 and XPR1 [1,4]. These techniques provide atomic-level details of the binding pocket and conformational changes induced by InsP6.
Proteomics
Proteome-wide quantification of inositol pyrophosphate-protein interactions has been achieved using chemical probes and mass spectrometry. This approach can identify new InsP6-binding proteins and quantify binding affinities on a global scale.
Functional Assays
Cell-based assays measuring downstream effects of InsP6 binding, such as catecholamine release from chromaffin cells or DNA repair efficiency in Ku70/80 mutants, are essential to link binding to function.
How CRISPR Can Be Used to Study GO:0000822 inositol hexakisphosphate binding
Knockout
CRISPR knockout of genes encoding InsP6-binding proteins, such as KU70 or Integrator subunits, can reveal their essential roles in DNA repair and RNA processing [3,7]. Knockout cell lines are valuable for assessing loss-of-function phenotypes and for identifying compensatory pathways.
Point Mutation
Introducing point mutations in the InsP6-binding pocket (e.g., substituting basic residues with alanine) allows researchers to specifically abolish InsP6 binding without affecting overall protein structure. This approach has been used to study the role of InsP6 in plant NLR autoinhibition.
Knock-in
Knock-in of tagged versions of InsP6-binding proteins (e.g., GFP or HA tags) enables visualization and immunoprecipitation. Additionally, knock-in of disease-associated mutations can model their effects on InsP6 binding and downstream signaling.
Overexpression
Overexpression of wild-type or InsP6-binding-deficient mutants can help determine whether phenotypes are due to gain-of-function or dominant-negative effects. This is particularly useful for studying proteins like XPR1 in phosphate export.
How EDITGENE Supports inositol hexakisphosphate binding Research
Researchers studying inositol hexakisphosphate binding-related genes often need to determine whether a candidate gene is causally involved in a specific biological process or disease. EDITGENE provides a comprehensive suite of CRISPR-based services to generate precisely engineered cell models, enabling functional validation and mechanistic studies.
Contact EDITGENE today to design your custom CRISPR model for inositol hexakisphosphate binding research.
Related Products
| Product name | Cat.No. | Species | Gene ID | |
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| ITPR3 Knockout HEK293 Cell Line | EDJ-KQ1424 | Human | 3710 | Details Get a Quote |
| XPR1 Knockout HEK293 Cell Line | EDJ-KQ6505 | Human | 9213 | Details Get a Quote |
| ITPR3 Knockout HCT 116 Cell Line | EDJ-KQ20966 | Human | 3710 | Details Get a Quote |
| ITPR3 Knockout HeLa Cell Line | EDJ-KQ20967 | Human | 3710 | Details Get a Quote |
| ITPR3 Knockout A-549 Cell Line | EDJ-KQ19627 | Human | 3710 | Details Get a Quote |
| XPR1 Knockout A-549 Cell Line | EDJ-KQ30647 | Human | 9213 | Details Get a Quote |
| XPR1 Knockout HCT 116 Cell Line | EDJ-KQ30648 | Human | 9213 | Details Get a Quote |
| XPR1 Knockout HeLa Cell Line | EDJ-KQ30649 | Human | 9213 | Details Get a Quote |
| MTOR (p.L2303=) Point Mutation in HAP1 Cell Line | EDC03557 | Human | 2475 | Details Get a Quote |
| MTOR (p.S1851=) Point Mutation in HAP1 Cell Line | EDC03558 | Human | 2475 | Details Get a Quote |
| MTOR (c.4253+4718A>G )Point Mutation in HAP1 Cell Line | EDC03559 | Human | 2475 | Details Get a Quote |
Frequently Asked Questions About inositol hexakisphosphate binding
What is inositol hexakisphosphate binding?
Inositol hexakisphosphate binding (GO:0000822) is a molecular function defined as the binding to inositol hexakisphosphate (InsP6), a highly phosphorylated inositol derivative. This binding is involved in diverse cellular processes, including hormone signaling, DNA repair, and immune regulation [1,7,8].
What genes are involved in inositol hexakisphosphate binding?
Genes encoding proteins that bind InsP6 include TIR1, XPR1, KU70, KU80, and subunits of the Integrator complex, among others [1,3,4,7].
How does InsP6 binding affect protein function?
InsP6 binding can act as a structural cofactor, allosteric regulator, or facilitate protein-protein interactions, thereby modulating protein stability, localization, and activity [3,4,8].
What diseases are associated with inositol hexakisphosphate binding?
Dysregulation of InsP6 binding has been linked to cancer, neurodegeneration, and immune disorders, as well as plant autoimmune responses [3,7,8].
What methods are used to study InsP6 binding?
Common methods include radioligand binding assays, isothermal titration calorimetry, X-ray crystallography, cryo-EM, and proteome-wide mass spectrometry [1,2,4,6].
Can CRISPR be used to study InsP6 binding?
Yes, CRISPR knockout, point mutation, knock-in, and overexpression models are powerful tools to dissect the functional significance of InsP6 binding in cells and organisms [3,7,8].
What is the role of InsP6 in DNA repair?
InsP6 binds to the Ku70/80 heterodimer, which is essential for non-homologous end joining, a major DNA double-strand break repair pathway.
How does InsP6 regulate the Integrator complex?
InsP6 is required for the assembly and function of the Integrator complex, which processes small nuclear RNAs and regulates transcription.
Is InsP6 binding conserved across species?
Yes, InsP6 binding proteins have been identified in plants, animals, and fungi, indicating evolutionary conservation of this regulatory mechanism [1,8].
What are the therapeutic implications of targeting InsP6 binding?
Modulating InsP6-protein interactions could offer new strategies for treating cancer, neurodegenerative diseases, and immune disorders, though further research is needed [3,7,8].
Conclusion
Inositol hexakisphosphate binding (GO:0000822) is a fundamental molecular function that connects a ubiquitous metabolite to a wide array of cellular processes, from plant hormone signaling to human DNA repair and immunity. The diversity of InsP6-binding proteins and their involvement in disease underscore the importance of this interaction as a research focus. With advanced CRISPR tools and bioinformatics, EDITGENE empowers researchers to unravel the mechanistic details and therapeutic potential of InsP6 binding.
References
- 1. Tan X et al.. 2007. Mechanism of auxin perception by the TIR1 ubiquitin ligase.. Nature 446(7136):640-5 PMID: 17410169
- 2. Rowley KG et al.. 1996. Inositol hexakisphosphate binding sites in rat heart and brain.. Br J Pharmacol 118(7):1615-20 PMID: 8842422
- 3. Lin MH et al.. 2022. Inositol hexakisphosphate is required for Integrator function.. Nat Commun 13(1):5742 PMID: 36180473
- 4. Yan R et al.. 2024. Human XPR1 structures reveal phosphate export mechanism.. Nature 633(8031):960-967 PMID: 39169184
- 5. Regunathan S et al.. 1992. Specific binding of inositol hexakisphosphate (phytic acid) to adrenal chromaffin cell membranes and effects on calcium-dependent catecholamine release.. Biochem Pharmacol 43(6):1331-6 PMID: 1562283
- 6. Richter A et al.. 2026. Proteome-wide quantification of inositol pyrophosphate-protein interactions.. Nat Commun 17(1) PMID: 42243085
- 7. Ma Y et al.. 2002. Binding of inositol hexakisphosphate (IP6) to Ku but not to DNA-PKcs.. J Biol Chem 277(13):10756-9 PMID: 11821378
- 8. Ma S et al.. 2024. Oligomerization-mediated autoinhibition and cofactor binding of a plant NLR.. Nature 632(8026):869-876 PMID: 38866053
