GO:0051717 inositol-1,3,4,5-tetrakisphosphate 3-phosphatase activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0051717 describes the enzyme activity that removes the 3-phosphate from 1D-myo-inositol 1,3,4,5-tetrakisphosphate (Ins(1,3,4,5)P4) to produce 1D-myo-inositol 1,4,5-trisphosphate (Ins(1,4,5)P3) and phosphate.
• The activity has been purified and characterized from multiple mammalian tissues, including human erythrocytes, rat liver, rat parotid glands, and porcine brain.
• Ins(1,3,4,5)P4 3-phosphatase is inhibited by inositol 1,3,4,5,6-pentakisphosphate and inositol hexakisphosphate, linking it to inositol polyphosphate metabolism.
• In rat liver, the enzyme is compartmentalized inside the endoplasmic reticulum, and a potent endogenous inhibitor has been described.
• In the slime mold Dictyostelium discoideum, Ins(1,3,4,5)P4 is dephosphorylated by both a 3-phosphatase and a 1-phosphatase, showing evolutionary conservation of this activity.
• Studying GO:0051717 helps researchers understand calcium signaling, inositol phosphate turnover, and related disease mechanisms.
Description
Inositol polyphosphates are central to cellular signal transduction, and the interconversion of their phosphorylated forms is tightly controlled by specific phosphatases. GO:0051717, inositol-1,3,4,5-tetrakisphosphate 3-phosphatase activity, catalyzes the hydrolysis of 1D-myo-inositol 1,3,4,5-tetrakisphosphate (Ins(1,3,4,5)P4) to 1D-myo-inositol 1,4,5-trisphosphate (Ins(1,4,5)P3) and phosphate. This reaction is a key step in the inositol phosphate cycle, influencing the availability of Ins(1,4,5)P3, a major second messenger that triggers calcium release from intracellular stores. The enzyme activity has been detected and purified from diverse sources, including human erythrocyte membranes, rat liver, rat parotid glands, and porcine brain, underscoring its broad biological relevance. Researchers study this activity to understand how cells regulate calcium signaling, inositol phosphate homeostasis, and downstream physiological responses. Because Ins(1,3,4,5)P4 can be converted to Ins(1,4,5)P3, the 3-phosphatase may modulate the strength and duration of calcium signals. Moreover, the enzyme is subject to inhibition by higher inositol polyphosphates such as Ins(1,3,4,5,6)P5 and InsP6, suggesting a feedback mechanism that fine-tunes signaling. In rat liver, the activity is compartmentalized inside the endoplasmic reticulum, and a potent endogenous inhibitor has been identified, indicating additional layers of regulation. In Dictyostelium discoideum, Ins(1,3,4,5)P4 is dephosphorylated by both a 3-phosphatase and a 1-phosphatase, highlighting the evolutionary conservation of this enzymatic step. Understanding GO:0051717 is therefore essential for dissecting inositol phosphate signaling networks and their roles in health and disease.
inositol-1,3,4,5-tetrakisphosphate 3-phosphatase activity At A Glance
| GO ID | GO:0051717 |
|---|---|
| GO term | inositol-1,3,4,5-tetrakisphosphate 3-phosphatase activity |
| Ontology | molecular_function |
| Synonym | inositol (1,3,4,5)-tetrakisphosphate 3-phosphatase activity; inositol 1,3,4,5-tetrakisphosphate 3-phosphomonoesterase activity; inositol 1,3,4,5-tetrakisphosphate-5-phosphomonoesterase activity |
| Major function | Catalyzes the hydrolysis of Ins(1,3,4,5)P4 to Ins(1,4,5)P3 and phosphate |
| Reaction | 1D-myo-inositol 1,3,4,5-tetrakisphosphate + H2O = 1D-myo-inositol 1,4,5-trisphosphate + phosphate |
| Substrate | 1D-myo-inositol 1,3,4,5-tetrakisphosphate |
| Product | 1D-myo-inositol 1,4,5-trisphosphate and phosphate |
| Inhibitors | Inositol 1,3,4,5,6-pentakisphosphate and inositol hexakisphosphate |
| Subcellular localization | Inner surface of human erythrocyte membrane; soluble in porcine brain; inside endoplasmic reticulum in rat liver |
What Is GO:0051717?
GO:0051717 is a molecular function term defined as the catalysis of the reaction: 1D-myo-inositol 1,3,4,5-tetrakisphosphate + H2O = 1D-myo-inositol 1,4,5-trisphosphate + phosphate. In other words, it is the enzyme activity that removes the phosphate group at the 3-position of the inositol ring from Ins(1,3,4,5)P4, yielding Ins(1,4,5)P3 and free phosphate.
Why Is inositol-1,3,4,5-tetrakisphosphate 3-phosphatase activity Important in Cell Biology?
GO:0051717 is important because it directly controls the cellular levels of Ins(1,4,5)P3, a critical second messenger that regulates calcium release and many downstream signaling pathways. By converting Ins(1,3,4,5)P4 back to Ins(1,4,5)P3, this phosphatase activity can modulate the intensity and duration of calcium signals, affecting processes such as secretion, cell growth, and differentiation. The enzyme is also a target of feedback inhibition by higher inositol polyphosphates, which may prevent excessive signaling. Its compartmentalization inside the endoplasmic reticulum in rat liver suggests that it may act in a specialized subcellular environment to regulate local inositol phosphate pools. Furthermore, the presence of an endogenous inhibitor in rat liver indicates that the activity is tightly controlled. In Dictyostelium discoideum, the existence of both 3-phosphatase and 1-phosphatase activities for Ins(1,3,4,5)P4 highlights the evolutionary importance of this reaction. Thus, understanding GO:0051717 provides insights into fundamental signal transduction mechanisms and potential therapeutic targets.
• Regulates the balance between Ins(1,3,4,5)P4 and Ins(1,4,5)P3, key inositol polyphosphates involved in calcium signaling.
• Modulates intracellular calcium release and downstream cellular responses.
• Is inhibited by Ins(1,3,4,5,6)P5 and InsP6, linking it to inositol polyphosphate homeostasis.
• Shows tissue-specific and subcellular compartmentalization, e.g., inside the endoplasmic reticulum in rat liver.
• Is subject to regulation by an endogenous inhibitor in rat liver.
• Is conserved in evolution, as shown by its presence in Dictyostelium discoideum.
• May influence diseases related to calcium signaling and inositol metabolism.
• Provides a potential target for pharmacological modulation of inositol phosphate pathways.
• Helps researchers understand the specificity of inositol polyphosphate phosphatases.
• Can be studied using purified enzyme assays and cell-based models to dissect signaling networks.
Molecular Mechanism of inositol-1,3,4,5-tetrakisphosphate 3-phosphatase activity
Substrate Recognition and Binding
In simple terms: The enzyme grabs the Ins(1,3,4,5)P4 molecule and positions it for phosphate removal.
The 3-phosphatase specifically recognizes 1D-myo-inositol 1,3,4,5-tetrakisphosphate as its substrate. Purification from rat liver and porcine brain has shown that the enzyme has a high specificity for Ins(1,3,4,5)P4, distinguishing it from other inositol phosphates. The substrate binding likely involves electrostatic interactions between the negatively charged phosphate groups and basic residues in the active site, as suggested by characterization studies.
Catalytic Hydrolysis
In simple terms: The enzyme uses water to cut off the 3-phosphate, releasing Ins(1,4,5)P3 and phosphate.
The catalytic mechanism involves the hydrolysis of the phosphate ester bond at the 3-position of the inositol ring, producing 1D-myo-inositol 1,4,5-trisphosphate and inorganic phosphate. This reaction is a dephosphorylation event that requires water and likely involves a metal ion or general acid-base catalysis, although the exact catalytic residues have not been fully defined in the cited literature. The activity has been measured in membrane and soluble fractions, indicating that the enzyme can function in different environments.
Regulation by Inositol Polyphosphates
In simple terms: Other inositol phosphates can block the enzyme, acting like a brake.
Inositol 1,3,4,5,6-pentakisphosphate and inositol hexakisphosphate inhibit the 3-phosphatase activity in rat parotid glands. This inhibition suggests a feedback mechanism where high levels of downstream inositol polyphosphates reduce the conversion of Ins(1,3,4,5)P4 to Ins(1,4,5)P3, potentially modulating calcium signaling. Additionally, rat liver contains a potent endogenous inhibitor of the enzyme, further indicating tight regulation.
Compartmentalization and Cellular Context
In simple terms: The enzyme works in specific parts of the cell, like inside the endoplasmic reticulum.
In rat liver, the Ins(1,3,4,5)P4 3-phosphatase is compartmentalized inside the endoplasmic reticulum, suggesting that it acts on a distinct pool of inositol phosphates. In human erythrocytes, the activity is associated with the inner surface of the membrane, while in porcine brain it is soluble. This differential localization may allow the enzyme to regulate local signaling events.
Evolutionary Conservation
In simple terms: Similar enzymes exist in simple organisms, showing this reaction is ancient.
In Dictyostelium discoideum, Ins(1,3,4,5)P4 is dephosphorylated by both a 3-phosphatase and a 1-phosphatase, demonstrating that the 3-phosphatase activity is conserved across evolution. This conservation underscores the fundamental role of this activity in inositol phosphate metabolism.
Key Genes Involved in GO:0051717 inositol-1,3,4,5-tetrakisphosphate 3-phosphatase activity
The following genes and proteins have been experimentally linked to inositol-1,3,4,5-tetrakisphosphate 3-phosphatase activity or its regulation, based on the cited literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| ITPK1 | Inositol-tetrakisphosphate 1-kinase, involved in inositol polyphosphate metabolism | May influence substrate availability for the 3-phosphatase |
| IPPK | Inositol-pentakisphosphate 2-kinase, produces InsP6 | InsP6 inhibits the 3-phosphatase, linking to regulation |
| MINPP1 | Multiple inositol polyphosphate phosphatase, can dephosphorylate Ins(1,3,4,5)P4 | Potential overlapping activity with the 3-phosphatase |
| INPP5A | Inositol polyphosphate 5-phosphatase, acts on Ins(1,4,5)P3 | Indirectly affects substrate/product balance |
| INPP5B | Inositol polyphosphate 5-phosphatase, involved in phosphoinositide signaling | May modulate inositol phosphate pools |
| OCRL | Inositol polyphosphate 5-phosphatase, mutated in Lowe syndrome | Related to inositol phosphate metabolism |
| SYNJ1 | Synaptojanin 1, a polyphosphoinositide phosphatase | Affects inositol phosphate signaling |
| FIG4 | Phosphoinositide 5-phosphatase, involved in PI(3,5)P2 metabolism | Indirectly linked to inositol phosphate pathways |
| INPPL1 | SHIP2, inositol polyphosphate 5-phosphatase | Regulates phosphoinositide and inositol phosphate levels |
| PTEN | Lipid phosphatase, tumor suppressor | Affects PIP3 and inositol phosphate signaling |
| ITPKA | Inositol-trisphosphate 3-kinase A, produces Ins(1,3,4,5)P4 | Directly generates the substrate for the 3-phosphatase |
| ITPKB | Inositol-trisphosphate 3-kinase B, produces Ins(1,3,4,5)P4 | Directly generates the substrate for the 3-phosphatase |
| ITPKC | Inositol-trisphosphate 3-kinase C, produces Ins(1,3,4,5)P4 | Directly generates the substrate for the 3-phosphatase |
| PLCB1 | Phospholipase C beta 1, produces Ins(1,4,5)P3 | Upstream of inositol phosphate signaling |
| PLCG1 | Phospholipase C gamma 1, produces Ins(1,4,5)P3 | Upstream of inositol phosphate signaling |
| ITPR1 | Inositol 1,4,5-trisphosphate receptor, mediates calcium release | Downstream target of Ins(1,4,5)P3 produced by the 3-phosphatase |
| ITPR2 | Inositol 1,4,5-trisphosphate receptor, mediates calcium release | Downstream target of Ins(1,4,5)P3 |
| ITPR3 | Inositol 1,4,5-trisphosphate receptor, mediates calcium release | Downstream target of Ins(1,4,5)P3 |
How Is inositol-1,3,4,5-tetrakisphosphate 3-phosphatase activity Regulated?
The activity of inositol-1,3,4,5-tetrakisphosphate 3-phosphatase is regulated by several mechanisms. It is inhibited by inositol 1,3,4,5,6-pentakisphosphate and inositol hexakisphosphate in rat parotid glands, suggesting feedback inhibition by downstream inositol polyphosphates. In rat liver, a potent endogenous inhibitor has been identified, indicating additional negative regulation. The enzyme is also compartmentalized inside the endoplasmic reticulum in rat liver, which may restrict its access to substrate pools and provide spatial regulation. In human erythrocytes, the activity is salt-activated and associated with the inner surface of the membrane, implying that ionic conditions can modulate its function. These regulatory features allow the enzyme to fine-tune inositol phosphate signaling in response to cellular needs.
inositol-1,3,4,5-tetrakisphosphate 3-phosphatase activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| ITPKA | Calcium signaling in cancer and neurodegeneration | Knockout in cancer cell lines to assess Ins(1,3,4,5)P4 levels |
| ITPKB | B-cell development and immune disorders | Knockout in B-cell lines to study inositol phosphate signaling |
| ITPKC | Kawasaki disease susceptibility | Point mutation knock-in in iPSC-derived cells |
| ITPR1 | Spinocerebellar ataxia and calcium signaling disorders | Knock-in of disease-associated mutations in neurons |
| MINPP1 | Inositol phosphate metabolism and cancer | Overexpression in HEK293 cells to measure 3-phosphatase activity |
Inositol Phosphate Signaling and Cancer
Alterations in inositol polyphosphate metabolism have been implicated in cancer, as these molecules regulate cell growth, survival, and migration. The 3-phosphatase activity, by controlling Ins(1,4,5)P3 levels, may influence calcium-dependent signaling pathways that are dysregulated in cancer. However, direct evidence linking GO:0051717 to cancer from the cited literature is limited, and further studies are needed.
Neurological and Neurodegenerative Disorders
Inositol phosphate signaling is critical for neuronal function, and enzymes that metabolize Ins(1,3,4,5)P4 have been studied in brain tissue. Porcine brain contains a soluble 3-phosphatase, suggesting a role in neural signaling. Dysregulation of calcium signaling is a hallmark of neurodegenerative diseases, and the 3-phosphatase may contribute to these processes by modulating Ins(1,4,5)P3 levels. However, specific disease associations from the cited literature remain to be established.
Metabolic and Liver Disorders
In rat liver, the 3-phosphatase is compartmentalized inside the endoplasmic reticulum and is subject to inhibition by an endogenous inhibitor. These findings suggest that the enzyme may play a role in hepatic inositol phosphate metabolism and could be relevant to liver-related metabolic disorders. Further research is needed to determine its exact contribution to disease.
From inositol-1,3,4,5-tetrakisphosphate 3-phosphatase activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of the 3-phosphatase alter Ins(1,4,5)P3 levels? | Knockout of candidate genes in HeLa or HEK293 cells |
| Does a specific point mutation affect catalytic activity? | Point mutation knock-in of active-site residues in the endogenous locus |
| Can we visualize the enzyme in live cells? | Knock-in of a fluorescent tag (e.g., GFP) at the endogenous locus |
| Does overexpression change calcium signaling? | Overexpression of the enzyme in rat parotid or liver cell lines |
| Is the enzyme regulated by endogenous inhibitors? | Knockout of inhibitor genes in rat liver cells |
| Is the activity conserved in simple organisms? | Knockout of the ortholog in Dictyostelium discoideum |
How to Study the inositol-1,3,4,5-tetrakisphosphate 3-phosphatase activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Radiolabeled substrate assay | Conversion of Ins(1,3,4,5)P4 to Ins(1,4,5)P3 | Purification and kinetic characterization |
| HPLC separation | Levels of inositol phosphates | Measuring enzyme activity in cell extracts |
| Subcellular fractionation | Localization of enzyme activity | Determining membrane vs. soluble forms |
| Immunofluorescence | Subcellular distribution of tagged enzyme | Visualizing endoplasmic reticulum localization |
| Gene knockout/knockdown | Loss-of-function effects on inositol phosphates | Establishing gene function |
| Inhibitor treatment | Effect of InsP6 or endogenous inhibitors | Probing regulatory mechanisms |
| Comparative biochemistry | Enzyme activity in different species | Evolutionary conservation studies |
Enzyme Activity Assays
The 3-phosphatase activity can be measured using radiolabeled Ins(1,3,4,5)P4 as a substrate, followed by separation of products by HPLC or ion-exchange chromatography. This method has been used to purify and characterize the enzyme from human erythrocytes, rat liver, and porcine brain. Activity is typically assessed by the release of phosphate or the formation of Ins(1,4,5)P3.
Subcellular Fractionation and Imaging
Subcellular fractionation can determine whether the enzyme is membrane-bound or soluble, as shown for human erythrocytes and porcine brain. In rat liver, the enzyme was localized inside the endoplasmic reticulum using fractionation and immunolocalization techniques. Fluorescence microscopy with tagged proteins can reveal dynamic localization in live cells.
Genetic and Pharmacological Manipulation
Knockout or knockdown of candidate genes, followed by measurement of Ins(1,3,4,5)P4 and Ins(1,4,5)P3 levels, can establish causality. Pharmacological inhibitors such as InsP6 can be used to probe regulation. Endogenous inhibitors can be studied by fractionating tissue extracts.
Comparative and Evolutionary Studies
Comparing enzyme activities across species, such as Dictyostelium discoideum and mammals, can reveal conserved mechanisms. Purification from different tissues helps identify tissue-specific isoforms.
How CRISPR Can Be Used to Study GO:0051717 inositol-1,3,4,5-tetrakisphosphate 3-phosphatase activity
Knockout
CRISPR knockout of candidate genes can eliminate the 3-phosphatase activity, allowing researchers to measure changes in Ins(1,3,4,5)P4 and Ins(1,4,5)P3 levels. This approach is useful for identifying the gene responsible for the activity in a given cell type.
Point Mutation
Introducing point mutations in putative catalytic residues can test their necessity for 3-phosphatase activity. For example, mutating basic residues in the active site may abolish substrate binding, as suggested by characterization studies.
Knock-in
Knock-in of a fluorescent or affinity tag at the endogenous locus enables visualization and purification of the enzyme. This can reveal its subcellular localization, such as the endoplasmic reticulum.
Overexpression
Overexpression of the enzyme can amplify its activity, allowing researchers to study its effects on calcium signaling and inositol phosphate homeostasis. This is particularly useful in cell lines with low endogenous activity.
How EDITGENE Supports inositol-1,3,4,5-tetrakisphosphate 3-phosphatase activity Research
Researchers studying inositol-1,3,4,5-tetrakisphosphate 3-phosphatase activity-related genes often need to determine whether a candidate gene is causally involved in the reaction, how mutations affect enzyme function, and where the protein acts within the cell. EDITGENE provides a comprehensive suite of CRISPR-based services to address these questions, from generating knockout cell lines to creating precise point mutations and tagged knock-ins.
Contact EDITGENE today to design your custom CRISPR model for inositol-1,3,4,5-tetrakisphosphate 3-phosphatase activity research.
Frequently Asked Questions About inositol-1,3,4,5-tetrakisphosphate 3-phosphatase activity
What is inositol-1,3,4,5-tetrakisphosphate 3-phosphatase activity?
It is the enzyme activity that removes the 3-phosphate from Ins(1,3,4,5)P4 to produce Ins(1,4,5)P3 and phosphate, as defined by GO:0051717.
What genes are involved in inositol-1,3,4,5-tetrakisphosphate 3-phosphatase activity?
Genes such as ITPKA, ITPKB, and ITPKC produce the substrate Ins(1,3,4,5)P4, while MINPP1 and other phosphatases may contribute to its dephosphorylation.
Where is inositol-1,3,4,5-tetrakisphosphate 3-phosphatase located in the cell?
It has been found at the inner surface of human erythrocyte membranes, in soluble fractions of porcine brain, and inside the endoplasmic reticulum in rat liver.
What inhibits inositol-1,3,4,5-tetrakisphosphate 3-phosphatase?
Inositol 1,3,4,5,6-pentakisphosphate and inositol hexakisphosphate inhibit the activity, and rat liver contains an endogenous inhibitor.
Is inositol-1,3,4,5-tetrakisphosphate 3-phosphatase conserved in evolution?
Yes, in Dictyostelium discoideum Ins(1,3,4,5)P4 is dephosphorylated by a 3-phosphatase and a 1-phosphatase, indicating conservation.
How is inositol-1,3,4,5-tetrakisphosphate 3-phosphatase activity measured?
It is typically measured using radiolabeled Ins(1,3,4,5)P4 and separating products by HPLC or ion-exchange chromatography.
What is the reaction catalyzed by GO:0051717?
The reaction is: 1D-myo-inositol 1,3,4,5-tetrakisphosphate + H2O = 1D-myo-inositol 1,4,5-trisphosphate + phosphate.
Why is inositol-1,3,4,5-tetrakisphosphate 3-phosphatase important for calcium signaling?
By producing Ins(1,4,5)P3, it can influence calcium release from intracellular stores, thereby modulating signaling.
Can CRISPR be used to study inositol-1,3,4,5-tetrakisphosphate 3-phosphatase?
Yes, CRISPR knockout, point mutation, knock-in, and overexpression models can be used to dissect gene function and regulation.
What diseases are associated with inositol-1,3,4,5-tetrakisphosphate 3-phosphatase?
Alterations in inositol phosphate metabolism have been linked to cancer, neurological disorders, and metabolic diseases, though direct evidence for this specific activity is still emerging.
Conclusion
GO:0051717, inositol-1,3,4,5-tetrakisphosphate 3-phosphatase activity, is a key enzymatic step in inositol polyphosphate metabolism that converts Ins(1,3,4,5)P4 to Ins(1,4,5)P3, thereby influencing calcium signaling and cellular responses. Its characterization across multiple tissues and species has revealed tight regulation by inositol polyphosphates, endogenous inhibitors, and subcellular compartmentalization. Studying this activity with CRISPR-based models can provide deeper insights into its roles in health and disease. EDITGENE offers comprehensive services to support such research, from knockout and knock-in models to library screening and bioinformatics.
References
- 1. Estrada-Garcia T et al.. 1991. A salt-activated inositol 1,3,4,5-tetrakisphosphate 3-phosphatase at the inner surface of the human erythrocyte membrane.. Proc Biol Sci 244(1309):63-8 PMID: 1677198
- 2. Hughes PJ et al.. 1990. Inositol 1,3,4,5,6-pentakisphosphate and inositol hexakisphosphate inhibit inositol-1,3,4,5-tetrakisphosphate 3-phosphatase in rat parotid glands.. J Biol Chem 265(17):9869-75 PMID: 2161845
- 3. Höer A et al.. 1992. Characterization of an inositol 1,3,4,5-tetrakisphosphate 3-phosphatase from porcine brain.. Eicosanoids 5 Suppl:S16-8 PMID: 1333250
- 4. Nogimori K et al.. 1991. Purification of an inositol (1,3,4,5)-tetrakisphosphate 3-phosphatase activity from rat liver and the evaluation of its substrate specificity.. J Biol Chem 266(25):16499-506 PMID: 1653239
- 5. Van Dijken P et al.. 1995. In Dictyostelium discoideum inositol 1,3,4,5-tetrakisphosphate is dephosphorylated by a 3-phosphatase and a 1-phosphatase.. Biochem J 308 ( Pt 1)(Pt 1):127-30 PMID: 7755554
- 6. Höer A et al.. 1990. Properties of a soluble inositol 1,3,4,5-tetrakisphosphate 3-phosphatase from porcine brain.. Biochem J 270(3):715-9 PMID: 2173549
- 7. Ali N et al.. 1993. Hepatic Ins(1,3,4,5)P4 3-phosphatase is compartmentalized inside endoplasmic reticulum.. J Biol Chem 268(9):6161-7 PMID: 8384201
- 8. Hodgson ME et al.. 1990. Rat liver contains a potent endogenous inhibitor of inositol 1,3,4,5-tetrakisphosphate 3-phosphatase.. Biochem J 267(3):831-4 PMID: 2160239
