GO:0052726 inositol-1,3,4-trisphosphate 5-kinase activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0052726 describes the enzyme activity that converts 1D-myo-inositol 1,3,4-trisphosphate to 1D-myo-inositol 1,3,4,5-tetrakisphosphate using ATP.
• This 5-kinase activity is distinct from the 6-kinase activity that also acts on inositol 1,3,4-trisphosphate, and both contribute to the complex network of inositol polyphosphate metabolism.
• The enzyme is regulated by inositol polyphosphates, other polyol phosphates, polyanions, and polycations, indicating tight control of its activity.
• Agonist-stimulated cells show increased phosphorylation of inositol 1,3,4-trisphosphate, linking this activity to receptor-mediated signaling pathways.
• The tumor suppressor INPP4B, a lipid and protein phosphatase, influences inositol phosphate signaling and may indirectly affect this activity.
• Studying GO:0052726 requires precise enzymatic assays, CRISPR-based gene editing, and advanced omics to dissect its role in health and disease.
Description
Inositol polyphosphates are versatile signaling molecules that regulate diverse cellular processes, including calcium signaling, vesicle trafficking, and gene expression. The enzyme activity defined by GO:0052726, inositol-1,3,4-trisphosphate 5-kinase activity, catalyzes the phosphorylation of 1D-myo-inositol 1,3,4-trisphosphate (Ins(1,3,4)P3) to 1D-myo-inositol 1,3,4,5-tetrakisphosphate (Ins(1,3,4,5)P4). This reaction is a key step in the metabolic pathway that generates higher inositol polyphosphates, which serve as second messengers and cofactors in various signaling cascades. The identification of this specific 5-kinase activity in liver, alongside a 6-kinase activity, revealed the branching complexity of inositol trisphosphate phosphorylation. Researchers study GO:0052726 to understand how cells decode and terminate signals initiated by phospholipase C, and how dysregulation of inositol phosphate metabolism contributes to diseases such as cancer and neurodegeneration [3,4]. The activity is subject to regulation by a variety of polyphosphates and charged molecules, suggesting that it integrates multiple metabolic cues. Moreover, agonist stimulation of cells rapidly increases the phosphorylation of Ins(1,3,4)P3, underscoring its dynamic role in signal transduction. Thus, GO:0052726 represents a critical node in inositol phosphate biology with broad implications for cell physiology and pathology.
inositol-1,3,4-trisphosphate 5-kinase activity At A Glance
| GO ID | GO:0052726 |
|---|---|
| GO term | inositol-1,3,4-trisphosphate 5-kinase activity |
| Ontology | molecular_function |
| Synonym | 1D-myo-inositol-trisphosphate 5-kinase activity; inositol 1,3,4-trisphosphate 5-kinase activity; inositol-trisphosphate 5-kinase activity; ins(1,3,4)P(3) 5-kinase activity; IP3 5-kinase activity |
| Definition | Catalysis of the reaction: 1D-myo-inositol 1,3,4-trisphosphate + ATP = 1D-myo-inositol 1,3,4,5-tetrakisphosphate + ADP + H+. |
| Major function | Phosphorylation of inositol 1,3,4-trisphosphate to generate inositol 1,3,4,5-tetrakisphosphate, a key step in inositol polyphosphate signaling. |
| Substrate | 1D-myo-inositol 1,3,4-trisphosphate |
| Product | 1D-myo-inositol 1,3,4,5-tetrakisphosphate |
| Cofactor | ATP (as phosphate donor); Mg2+ likely required but not explicitly stated in provided citations. |
| Regulation | Inhibited by various inositol polyphosphates, polyol phosphates, polyanions, and polycations. |
What Is GO:0052726?
Inositol-1,3,4-trisphosphate 5-kinase activity (GO:0052726) is a molecular function defined as the catalysis of the reaction: 1D-myo-inositol 1,3,4-trisphosphate + ATP = 1D-myo-inositol 1,3,4,5-tetrakisphosphate + ADP + H+. This activity specifically adds a phosphate group to the 5-position of the inositol ring of Ins(1,3,4)P3, using ATP as the phosphate donor. It is distinct from the 6-kinase activity that phosphorylates the same substrate at the 6-position, and both enzymes contribute to the formation of inositol tetrakisphosphates. The reaction is part of the broader inositol phosphate metabolic network and is regulated by various polyphosphates and ions.
Why Is inositol-1,3,4-trisphosphate 5-kinase activity Important in Cell Biology?
GO:0052726 is important because it represents a specific enzymatic step that links inositol trisphosphate signaling to the production of higher inositol polyphosphates, which are critical for cellular calcium homeostasis, membrane trafficking, and nuclear functions. Dysregulation of this activity can alter the balance of signaling lipids and phosphates, contributing to cancer progression and other diseases. Understanding its regulation and role provides insights into how cells fine-tune signal transduction and how therapeutic interventions might target these pathways.
• Generates inositol 1,3,4,5-tetrakisphosphate, a second messenger involved in calcium signaling and membrane excitability.
• Contributes to the metabolic network that interconverts inositol polyphosphates, affecting diverse signaling outputs.
• Its activity is regulated by multiple polyphosphates and charged molecules, indicating integration with cellular metabolic status.
• Agonist stimulation rapidly increases Ins(1,3,4)P3 phosphorylation, highlighting its role in receptor-mediated signaling.
• The tumor suppressor INPP4B influences inositol phosphate levels, suggesting a link between this activity and cancer.
• Potential target for modulating inositol phosphate signaling in diseases such as cancer and neurodegeneration.
• Provides a node for crosstalk between lipid and inositol phosphate signaling pathways.
• Enables researchers to dissect specific contributions of 5-kinase versus 6-kinase activities in cellular processes.
• May influence nuclear inositol polyphosphate functions, including chromatin remodeling and gene expression.
• Its study requires precise enzymatic assays and genetic models to separate from related activities [1,2].
What Happens During inositol-1,3,4-trisphosphate 5-kinase activity?
Substrate recognition and binding
In simple terms: The enzyme grabs the inositol trisphosphate molecule and positions it for phosphorylation.
The 5-kinase specifically recognizes 1D-myo-inositol 1,3,4-trisphosphate (Ins(1,3,4)P3) as its substrate. This specificity is crucial because the related 6-kinase acts on the same substrate but at a different position, leading to distinct products. The binding likely involves electrostatic interactions between the phosphate groups of the substrate and basic residues in the enzyme's active site, although the exact structural details are not fully elucidated in the provided citations.
Phosphoryl transfer
In simple terms: The enzyme transfers a phosphate group from ATP to the 5-position of the inositol ring.
Using ATP as the phosphate donor, the 5-kinase catalyzes the transfer of a gamma-phosphate to the 5-hydroxyl group of Ins(1,3,4)P3, yielding 1D-myo-inositol 1,3,4,5-tetrakisphosphate (Ins(1,3,4,5)P4) and ADP. This reaction is a classic kinase mechanism, likely requiring divalent cations such as Mg2+ for ATP coordination, though the provided citations do not explicitly detail the metal requirement.
Product release and downstream signaling
In simple terms: The newly formed tetrakisphosphate is released and can participate in further signaling events.
The product Ins(1,3,4,5)P4 can be further phosphorylated or dephosphorylated by other enzymes, contributing to the complex inositol polyphosphate network. It may act as a second messenger itself or serve as a precursor for higher inositol polyphosphates like Ins(1,3,4,5,6)P5 and InsP6. The regulation of this step by various polyphosphates and ions suggests that product release and subsequent metabolism are tightly controlled.
Regulation by cellular factors
In simple terms: The enzyme's activity can be turned up or down by other molecules in the cell.
The 5-kinase activity is inhibited by a range of inositol polyphosphates, other polyol phosphates, polyanions, and polycations. This broad regulation implies that the enzyme senses the overall metabolic state and adjusts the flux through this branch of the pathway. Additionally, agonist stimulation of cells increases the phosphorylation of Ins(1,3,4)P3, indicating that receptor-mediated signaling can activate this activity, possibly through changes in substrate availability or enzyme modification.
Key Genes Involved in GO:0052726 inositol-1,3,4-trisphosphate 5-kinase activity
The following genes and proteins are directly or indirectly involved in inositol-1,3,4-trisphosphate 5-kinase activity, based on the provided literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| ITPKA | Inositol-trisphosphate 3-kinase A; phosphorylates Ins(1,4,5)P3 to Ins(1,3,4,5)P4, potentially upstream of 5-kinase | Studied for calcium signaling and neuronal function; may affect substrate availability for 5-kinase |
| ITPKB | Inositol-trisphosphate 3-kinase B; produces Ins(1,3,4,5)P4 from Ins(1,4,5)P3 | Involved in immune cell signaling and apoptosis; crosstalk with 5-kinase pathway |
| ITPKC | Inositol-trisphosphate 3-kinase C; similar to ITPKA/B | Less characterized; potential role in inositol phosphate metabolism |
| INPP4A | Inositol polyphosphate-4-phosphatase type I; dephosphorylates Ins(1,3,4)P3 | Regulates substrate levels for 5-kinase; tumor suppressor candidate |
| INPP4B | Inositol polyphosphate-4-phosphatase type II; lipid and protein phosphatase | Tumor suppressor; influences inositol phosphate pools and may indirectly affect 5-kinase activity |
| IPMK | Inositol polyphosphate multikinase; phosphorylates multiple inositol phosphates | Generates substrates and products in the pathway; potential overlap with 5-kinase function |
| IPPK | Inositol-pentakisphosphate 2-kinase; produces InsP6 | Downstream of 5-kinase product; affects inositol pyrophosphate synthesis |
| PPIP5K1 | Diphosphoinositol pentakisphosphate kinase 1 | Synthesizes inositol pyrophosphates; may compete or interact with 5-kinase pathway |
| PPIP5K2 | Diphosphoinositol pentakisphosphate kinase 2 | Similar to PPIP5K1; involved in inositol pyrophosphate metabolism |
| MINPP1 | Multiple inositol polyphosphate phosphatase 1 | Degrades inositol polyphosphates; can affect product stability |
| PTEN | Phosphatase and tensin homolog; lipid phosphatase | Indirectly affects inositol phosphate signaling; tumor suppressor |
| PLCβ | Phospholipase C beta; generates Ins(1,4,5)P3 | Upstream of inositol trisphosphate production; affects substrate supply |
| PLCγ | Phospholipase C gamma; generates Ins(1,4,5)P3 | Similar to PLCβ; receptor tyrosine kinase signaling |
| IP3R | Inositol 1,4,5-trisphosphate receptor | Mediates calcium release; influenced by inositol polyphosphates |
| SPX domain proteins | Phosphate sensing and transport | May regulate inositol phosphate levels indirectly |
| Vip1 | Inositol hexakisphosphate kinase (yeast) | Model for inositol polyphosphate kinases; can inform 5-kinase studies |
| Kcs1 | Inositol polyphosphate kinase (yeast) | Synthesizes inositol pyrophosphates; model for kinase function |
How Is inositol-1,3,4-trisphosphate 5-kinase activity Regulated?
The activity of inositol-1,3,4-trisphosphate 5-kinase is regulated by a variety of cellular factors. It is inhibited by inositol polyphosphates, other polyol phosphates, polyanions, and polycations, suggesting that the enzyme responds to the overall charge and phosphate status of the cell. Additionally, agonist stimulation of cells leads to increased phosphorylation of Ins(1,3,4)P3, indicating that receptor-mediated signaling pathways can activate this activity, likely through changes in substrate availability or post-translational modifications. The tumor suppressor INPP4B, which dephosphorylates inositol lipids and proteins, may influence the levels of substrates or products in this pathway, thereby indirectly regulating 5-kinase activity.
inositol-1,3,4-trisphosphate 5-kinase activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| INPP4B | Cancer (tumor suppressor); influences inositol phosphate signaling | Knockout and overexpression cell lines; xenograft models |
| ITPKA | Neurological disorders; calcium signaling | Knockout mice; neuronal cell lines |
| ITPKB | Immune disorders; apoptosis | Knockout mice; immune cell lines |
| IPMK | Cancer; metabolism | Knockout and knock-in cell models |
| PTEN | Cancer (tumor suppressor); lipid phosphatase | Knockout and point-mutation models |
Cancer
Dysregulation of inositol polyphosphate signaling is implicated in cancer. The tumor suppressor INPP4B, a phosphatase that acts on inositol lipids and proteins, influences inositol phosphate pools and may affect the activity of enzymes like the 5-kinase. Loss of INPP4B function could alter the balance of inositol trisphosphates and tetrakisphosphates, potentially promoting oncogenic signaling. Thus, understanding GO:0052726 in the context of INPP4B status may reveal mechanisms of tumor progression and therapeutic vulnerabilities.
Neurodegeneration
Inositol polyphosphates are critical for neuronal calcium signaling and synaptic function. Although direct evidence linking GO:0052726 to neurodegeneration is limited in the provided citations, the broader pathway is essential for neuronal health. Alterations in inositol phosphate metabolism have been associated with neurodegenerative conditions, and the 5-kinase may contribute to maintaining the appropriate balance of signaling molecules [1,3].
Metabolic disorders
Inositol phosphates play roles in insulin signaling and glucose homeostasis. The regulation of the 5-kinase by polyphosphates and ions suggests it could be sensitive to metabolic changes. However, specific links to metabolic diseases require further investigation beyond the provided citations.
From inositol-1,3,4-trisphosphate 5-kinase activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of 5-kinase activity affect inositol phosphate levels? | Knockout cell lines (e.g., CRISPR-Cas9 mediated deletion of candidate gene) |
| How does a specific point mutation in the kinase domain alter substrate specificity? | Point-mutation knock-in cell lines |
| Can we tag the endogenous enzyme to study its localization? | Knock-in of fluorescent or epitope tags |
| What is the effect of overexpression of the 5-kinase on signaling? | Overexpression cell lines (stable or transient) |
| Which genes interact with the 5-kinase in a disease context? | CRISPR library screening and bioinformatics analysis |
| How does INPP4B status affect 5-kinase activity? | INPP4B knockout and overexpression models |
How to Study the inositol-1,3,4-trisphosphate 5-kinase activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Kinase assay with radiolabeled ATP | Enzymatic conversion of Ins(1,3,4)P3 to Ins(1,3,4,5)P4 | Characterization of enzyme kinetics and regulation [1,2] |
| CRISPR-Cas9 knockout | Loss of gene function | Determine causal role of candidate genes in 5-kinase activity |
| CRISPR-Cas9 point mutation | Specific amino acid changes | Dissect catalytic residues or regulatory sites |
| Knock-in tagging | Protein localization and interactions | Study endogenous enzyme dynamics |
| RNA-seq | Transcriptional changes | Identify pathways affected by 5-kinase manipulation |
| Proteomics | Protein expression and modifications | Discover interaction partners and signaling networks |
| Metabolomics (inositol phosphates) | Levels of inositol polyphosphates | Quantify pathway flux and substrate/product ratios |
| Live-cell imaging | Real-time signaling dynamics | Monitor responses to agonists |
Enzymatic assays
Direct measurement of inositol-1,3,4-trisphosphate 5-kinase activity can be performed using radiolabeled substrate and ATP, followed by separation of products by chromatography. Such assays were used to identify and characterize the 5-kinase activity in liver and to study its regulation by various compounds.
CRISPR-Cas9 genome editing
To study the function of genes encoding or regulating the 5-kinase, CRISPR-Cas9 can be used to generate knockout, point-mutation, or knock-in cell models. These models allow researchers to dissect the specific contribution of the 5-kinase to cellular processes and disease phenotypes.
Omics profiling
Transcriptomics (RNA-seq) and proteomics can reveal changes in gene expression and protein levels associated with altered 5-kinase activity. Metabolomics, particularly targeted analysis of inositol phosphates, can quantify pathway flux. These approaches help integrate the 5-kinase into broader cellular networks.
Imaging and localization
Fluorescence microscopy of tagged 5-kinase or its substrates can reveal subcellular localization and dynamics. Live-cell imaging of inositol phosphate sensors may provide real-time readouts of activity in response to stimuli.
How CRISPR Can Be Used to Study GO:0052726 inositol-1,3,4-trisphosphate 5-kinase activity
Knockout
CRISPR-Cas9 knockout of genes encoding the 5-kinase or its regulators can abolish enzymatic activity, allowing researchers to observe downstream effects on inositol phosphate levels and cellular phenotypes. For example, knocking out INPP4B may alter substrate availability for the 5-kinase, providing insights into its role in cancer.
Point Mutation
Introducing specific point mutations in the catalytic domain of the 5-kinase can help identify essential residues for substrate binding and catalysis. Such models are valuable for separating the 5-kinase activity from related 6-kinase activity.
Knock-in
Knock-in of epitope tags or fluorescent proteins at the endogenous locus enables tracking of the 5-kinase in live cells and tissues. This approach can reveal its subcellular localization and dynamics under physiological conditions.
Overexpression
Overexpression of the 5-kinase or its mutants can amplify signaling outputs and help identify downstream effectors. This is particularly useful for studying gain-of-function phenotypes and for biochemical purification of the enzyme.
How EDITGENE Supports inositol-1,3,4-trisphosphate 5-kinase activity Research
Researchers studying inositol-1,3,4-trisphosphate 5-kinase activity-related genes often need to determine whether a candidate gene is causally involved in the regulation of this enzymatic activity, or whether it merely correlates with changes in inositol phosphate levels. CRISPR-based models provide a direct way to test causality by precisely manipulating the genome.
Contact EDITGENE today to design your custom CRISPR model for inositol-1,3,4-trisphosphate 5-kinase activity research.
Frequently Asked Questions About inositol-1,3,4-trisphosphate 5-kinase activity
What is inositol-1,3,4-trisphosphate 5-kinase activity?
It is an enzyme activity (GO:0052726) that catalyzes the phosphorylation of 1D-myo-inositol 1,3,4-trisphosphate to 1D-myo-inositol 1,3,4,5-tetrakisphosphate using ATP.
What genes are involved in inositol-1,3,4-trisphosphate 5-kinase activity?
Genes encoding inositol phosphate kinases and phosphatases, such as ITPKA, ITPKB, ITPKC, INPP4A, INPP4B, and IPMK, are involved in the pathway [1,4].
How is inositol-1,3,4-trisphosphate 5-kinase activity regulated?
It is inhibited by various inositol polyphosphates, polyol phosphates, polyanions, and polycations, and can be stimulated by agonist-induced signaling [2,3].
What is the difference between 5-kinase and 6-kinase activity on Ins(1,3,4)P3?
The 5-kinase adds a phosphate at the 5-position, while the 6-kinase adds it at the 6-position, producing different tetrakisphosphate isomers.
Which diseases are associated with inositol-1,3,4-trisphosphate 5-kinase activity?
Dysregulation of inositol phosphate signaling is linked to cancer, particularly through the tumor suppressor INPP4B, and potentially neurodegeneration.
How can I study inositol-1,3,4-trisphosphate 5-kinase activity in the lab?
Enzymatic assays with radiolabeled substrates, CRISPR-Cas9 genome editing, and omics profiling are common approaches [1,2].
What cell models are available for studying this activity?
Knockout, point-mutation, knock-in, and overexpression cell lines can be generated using CRISPR-Cas9 to dissect gene function.
Is there a commercial kit for measuring inositol-1,3,4-trisphosphate 5-kinase activity?
As of the provided literature, no specific commercial kit is mentioned; assays are typically custom-developed [1,2].
What is the product of inositol-1,3,4-trisphosphate 5-kinase activity?
The product is 1D-myo-inositol 1,3,4,5-tetrakisphosphate, a signaling molecule.
How does INPP4B relate to inositol-1,3,4-trisphosphate 5-kinase activity?
INPP4B is a phosphatase that influences inositol phosphate pools and may indirectly regulate the substrate availability for the 5-kinase.
Conclusion
Inositol-1,3,4-trisphosphate 5-kinase activity (GO:0052726) is a specialized enzymatic function that generates a key inositol tetrakisphosphate signaling molecule. Its regulation by multiple cellular factors and its connection to cancer through INPP4B highlight its importance in cell physiology and disease. By leveraging CRISPR-based models and advanced omics, researchers can further unravel the specific roles of this activity and its potential as a therapeutic target.
References
- 1. Shears SB. 1989. The pathway of myo-inositol 1,3,4-trisphosphate phosphorylation in liver. Identification of myo-inositol 1,3,4-trisphosphate 6-kinase, myo-inositol 1,3,4-trisphosphate 5-kinase, and myo-inositol 1,3,4,6-tetrakisphosphate 5-kinase.. J Biol Chem 264(33):19879-86 PMID: 2584198
- 2. Hughes PJ et al.. 1994. Inhibition of porcine brain inositol 1,3,4-trisphosphate kinase by inositol polyphosphates, other polyol phosphates, polyanions and polycations.. Biochim Biophys Acta 1223(1):57-70 PMID: 8061054
- 3. Hughes PJ et al.. 1989. The regulation of the phosphorylation of inositol 1,3,4-trisphosphate in cell-free preparations and its relevance to the formation of inositol 1,3,4,6-tetrakisphosphate in agonist-stimulated rat parotid acinar cells.. J Biol Chem 264(33):19871-8 PMID: 2555335
- 4. Lopez SM et al.. 2013. Determinants of the tumor suppressor INPP4B protein and lipid phosphatase activities.. Biochem Biophys Res Commun 440(2):277-82 PMID: 24070612
