GO:0052658 inositol-1,4,5-trisphosphate 5-phosphatase activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0052658 describes the enzymatic activity that removes the 5-phosphate from inositol 1,4,5-trisphosphate (Ins(1,4,5)P3), converting it to inositol 1,4-bisphosphate and inorganic phosphate.
• This activity is a key off-switch for calcium-mobilizing Ins(1,4,5)P3 signals and therefore shapes the amplitude, duration and frequency of intracellular Ca2+ oscillations.
• The reaction is catalyzed by inositol polyphosphate 5-phosphatases, including INPP5A, INPP5B, INPP5D (SHIP1), INPPL1 (SHIP2), OCRL, INPP5E, INPP5J, INPP5K and SACM1L, which differ in substrate specificity and subcellular localization.
• Loss or inhibition of 5-phosphatase activity elevates Ins(1,4,5)P3 and can alter oncogenic signaling, calcium oscillations and cell survival, as shown in uveal melanoma.
• The activity is pharmacologically tractable: micromolar disulfiram and its analogues inhibit Ins(1,4,5)P3 5-phosphatase, linking this enzyme to drug-repurposing research.
• CRISPR knockout, point-mutation knock-in, tagged knock-in and overexpression models allow causal testing of specific 5-phosphatase genes in calcium signaling, cancer and immune cell biology.
Description
Inositol-1,4,5-trisphosphate 5-phosphatase activity (GO:0052658) is a molecular_function term describing the catalysis of the reaction 1D-myo-inositol 1,4,5-trisphosphate + H2O = 1D-myo-inositol 1,4-bisphosphate + phosphate. In cells, Ins(1,4,5)P3 is a second messenger generated by phospholipase C-mediated hydrolysis of phosphatidylinositol 4,5-bisphosphate, and its phosphorylation or dephosphorylation determines whether calcium signals are sustained or terminated. The 5-phosphatase reaction is one of the principal routes for Ins(1,4,5)P3 turnover, directly lowering the pool available to open Ins(1,4,5)P3 receptors on the endoplasmic reticulum. Because Ins(1,4,5)P3 controls cytosolic Ca2+ oscillations, the enzymes that carry GO:0052658 activity act as signal terminators and modulators of downstream Ca2+-dependent processes. Computational simulations have shown that the balance between Ins(1,4,5)P3 3-kinase and 5-phosphatase activities strongly influences the pattern of Ca2+ oscillations, making 5-phosphatases key determinants of signaling dynamics. In parallel, 3-kinase A regulates dendritic morphology and synaptic Ca2+ transients, illustrating how the opposing arms of Ins(1,4,5)P3 metabolism shape neuronal function. For researchers, GO:0052658 is therefore both a biochemical activity and a node in disease-relevant signaling. In uveal melanoma, inositol (1,4,5)-trisphosphate 5-phosphatase promotes survival by regulating oncogenic G protein-driven calcium oscillations. In human microglia, the 5-phosphatase INPP5D regulates inflammasome activation, connecting this activity to innate immune responses. These examples show why precise, citation-backed annotation of GO:0052658 matters for cancer biology, immunology and neuroscience.
inositol-1,4,5-trisphosphate 5-phosphatase activity At A Glance
| GO ID | GO:0052658 |
|---|---|
| GO term | inositol-1,4,5-trisphosphate 5-phosphatase activity |
| Ontology | molecular_function |
| Synonym | Ins(1,4,5)P3 5-phosphatase activity; 5PTase activity; inositol polyphosphate-5-phosphatase activity; type I inositol-polyphosphate phosphatase activity; type II inositol polyphosphate 5-phosphatase activity |
| Definition | Catalysis of the reaction: 1D-myo-inositol 1,4,5-trisphosphate + H2O = 1D-myo-inositol 1,4-bisphosphate + phosphate. |
| Major function | Terminates Ins(1,4,5)P3 calcium signaling by dephosphorylating the 5-position of the inositol ring. |
| Representative enzymes | INPP5A, INPP5B, INPP5D (SHIP1), INPPL1 (SHIP2), OCRL, INPP5E, INPP5J, INPP5K, SACM1L. |
| Substrate | 1D-myo-inositol 1,4,5-trisphosphate (Ins(1,4,5)P3). |
| Products | 1D-myo-inositol 1,4-bisphosphate and phosphate. |
| Pharmacological note | Micromolar disulfiram and its analogues inhibit Ins(1,4,5)P3 5-phosphatase activity. |
What Is GO:0052658?
GO:0052658, inositol-1,4,5-trisphosphate 5-phosphatase activity, is defined in QuickGO as the catalysis of the reaction: 1D-myo-inositol 1,4,5-trisphosphate + H2O = 1D-myo-inositol 1,4-bisphosphate + phosphate. In other words, the enzyme hydrolyzes the phosphate group at the 5-position of the inositol ring of Ins(1,4,5)P3, releasing free phosphate and leaving Ins(1,4)P2. This activity is a phosphomonoesterase reaction that terminates the calcium-mobilizing function of Ins(1,4,5)P3 and is classified under molecular_function.
Why Is inositol-1,4,5-trisphosphate 5-phosphatase activity Important in Cell Biology?
GO:0052658 is important because it controls the lifetime of one of the most widespread calcium-mobilizing second messengers in eukaryotic cells. By converting Ins(1,4,5)P3 to Ins(1,4)P2, 5-phosphatases set the threshold and kinetics of Ca2+ release, thereby influencing secretion, contraction, gene expression, immune activation and cell survival. Dysregulated 5-phosphatase activity has been linked to cancer cell survival and microglial inflammasome activation, making it a candidate target for experimental therapeutics and a key annotation for interpreting phosphoinositide signaling data.
• Terminates Ins(1,4,5)P3-mediated Ca2+ release, shaping the frequency and amplitude of Ca2+ oscillations.
• Balances the opposing Ins(1,4,5)P3 3-kinase pathway that produces Ins(1,3,4,5)P4 and regulates synaptic Ca2+ transients.
• Supports survival of uveal melanoma cells by modulating oncogenic G protein-driven calcium oscillations.
• Regulates inflammasome activation in human microglia through INPP5D, linking the activity to neuroinflammation.
• Is altered during hepatocarcinogenesis, where Ins(1,4,5)P3 turnover enzyme activities and subcellular distribution change.
• Is inhibited by disulfiram and analogues, providing a pharmacological entry point for tool-compound and drug-repurposing studies.
• Can be purified from brain tissue, enabling biochemical characterization of native 5-phosphatase enzymes.
• Provides a mechanistic explanation for phosphatidylinositol signaling reactions in cell growth and differentiation.
• Offers a causal handle for CRISPR screens aimed at calcium signaling, cancer and immune cell function.
Molecular Mechanism of inositol-1,4,5-trisphosphate 5-phosphatase activity
Substrate recognition and binding of Ins(1,4,5)P3
In simple terms: The enzyme first grabs the Ins(1,4,5)P3 molecule in a way that exposes its 5-phosphate.
Inositol polyphosphate 5-phosphatases bind 1D-myo-inositol 1,4,5-trisphosphate as their substrate and position the inositol ring so that the 5-phosphate is accessible to the catalytic site. Purification of bovine brain Ins(1,4,5)P3 5-phosphatase established that the native enzyme can be isolated and assayed for this specific phosphomonoesterase reaction. Substrate specificity among 5-phosphatases varies, with some enzymes preferring Ins(1,4,5)P3 and others acting on phosphatidylinositol polyphosphates or inositol tetrakisphosphates, but all catalyze removal of the 5-phosphate from the inositol ring.
Catalytic hydrolysis and product release
In simple terms: Water is used to cut off the 5-phosphate, leaving Ins(1,4)P2 and free phosphate.
The catalytic step follows the QuickGO definition: 1D-myo-inositol 1,4,5-trisphosphate + H2O = 1D-myo-inositol 1,4-bisphosphate + phosphate. This hydrolysis reaction converts the calcium-mobilizing Ins(1,4,5)P3 into Ins(1,4)P2, which does not efficiently open Ins(1,4,5)P3 receptors, thereby terminating the Ca2+ signal. The reaction is a phosphomonoesterase activity and is classified as inositol phosphate 5-phosphomonoesterase activity among its synonyms.
Regulation of Ca2+ oscillations by 5-phosphatase activity
In simple terms: By destroying the calcium-releasing messenger, the 5-phosphatase helps decide when calcium pulses stop.
Simulations of Ins(1,4,5)P3 3-kinase and 5-phosphatase activities demonstrated that the relative rates of these two enzymes strongly affect the pattern of Ca2+ oscillations. When 5-phosphatase activity is high, Ins(1,4,5)P3 is removed rapidly and Ca2+ oscillations are shortened or suppressed; when it is low, Ins(1,4,5)P3 persists and oscillations are prolonged. This regulatory logic explains why 5-phosphatases are considered signal terminators in phosphoinositide signaling.
Pharmacological inhibition and tool compounds
In simple terms: Certain drugs can block this enzyme, which changes how long the calcium signal lasts.
Micromolar concentrations of disulfiram and its analogues inhibit inositol 1,4,5-trisphosphate 5-phosphatase, providing a pharmacological tool to probe the contribution of this activity to cellular signaling. Such inhibitors are useful for comparing acute enzyme inhibition with genetic loss-of-function, because they can reveal whether phenotypes depend on catalytic activity or on scaffolding functions of the same protein.
Disease-relevant signaling contexts
In simple terms: In some tumors and immune cells, this enzyme helps keep calcium signals in a range that supports survival or inflammation.
In uveal melanoma, inositol (1,4,5)-trisphosphate 5-phosphatase promotes survival by regulating oncogenic G protein-driven calcium oscillations, showing that the activity can be co-opted by cancer cells. In human microglia, INPP5D regulates inflammasome activation, linking 5-phosphatase activity to innate immune signaling. In hepatocarcinogenesis, Ins(1,4,5)P3 turnover enzyme activities and their subcellular distribution are altered, suggesting that 5-phosphatase regulation is relevant to liver cancer biology.
Key Genes Involved in GO:0052658 inositol-1,4,5-trisphosphate 5-phosphatase activity
The following genes encode enzymes or related proteins that carry or modulate inositol-1,4,5-trisphosphate 5-phosphatase activity, based on published phosphoinositide signaling literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| INPP5A | Type I inositol polyphosphate 5-phosphatase acting on Ins(1,4,5)P3 | Model for calcium signal termination and cancer signaling. |
| INPP5B | Inositol polyphosphate 5-phosphatase with broad substrate range | Study of phosphoinositide turnover and membrane trafficking. |
| INPP5D (SHIP1) | 5-phosphatase acting on phosphatidylinositol 3,4,5-trisphosphate and inositol polyphosphates | Regulates inflammasome activation in human microglia. |
| INPPL1 (SHIP2) | 5-phosphatase regulating phosphatidylinositol 3,4,5-trisphosphate | Insulin signaling and phosphoinositide-dependent pathways. |
| OCRL | 5-phosphatase mutated in Lowe syndrome | Phosphoinositide metabolism and disease modeling. |
| INPP5E | Ciliary inositol polyphosphate 5-phosphatase | Cilia-related signaling and phosphoinositide homeostasis. |
| INPP5J | 5-phosphatase acting on inositol polyphosphates | Calcium signaling and membrane dynamics. |
| INPP5K | 5-phosphatase involved in endoplasmic reticulum and muscle biology | Phosphoinositide signaling in cell stress. |
| SACM1L | Sac1 domain-containing 5-phosphatase | Phosphoinositide turnover at membranes. |
| ITPKA | Ins(1,4,5)P3 3-kinase, opposing arm of Ins(1,4,5)P3 metabolism | Regulates dendritic morphology and synaptic Ca2+ transients. |
| ITPKB | Ins(1,4,5)P3 3-kinase family member | Balance with 5-phosphatase shapes Ca2+ oscillations. |
| PLCB1 | Phospholipase C producing Ins(1,4,5)P3 | Upstream source of substrate for 5-phosphatase. |
| ITPR1 | Ins(1,4,5)P3 receptor mediating Ca2+ release | Downstream readout of Ins(1,4,5)P3 levels. |
| GNAQ | G protein alpha subunit with oncogenic mutations | Oncogenic G protein-driven calcium oscillations in uveal melanoma. |
| GNA11 | G protein alpha subunit with oncogenic mutations | Uveal melanoma calcium signaling context. |
| CALM1 | Calmodulin, Ca2+ sensor | Readout of Ca2+ oscillations controlled by 5-phosphatase. |
| PIP4K2A | Phosphatidylinositol 5-phosphate 4-kinase | Phosphoinositide pathway context. |
| PIK3CA | Phosphatidylinositol 3-kinase catalytic subunit | Phosphoinositide signaling cross-talk. |
How Is inositol-1,4,5-trisphosphate 5-phosphatase activity Regulated?
Inositol-1,4,5-trisphosphate 5-phosphatase activity is regulated at multiple levels. At the reaction level, the balance between Ins(1,4,5)P3 3-kinase and 5-phosphatase activities determines whether Ins(1,4,5)P3 is converted to Ins(1,3,4,5)P4 or degraded to Ins(1,4)P2, and simulations show that this balance controls Ca2+ oscillation patterns. At the protein level, different 5-phosphatase family members have distinct subcellular localizations and substrate preferences, which spatially restrict the activity to specific membranes and compartments. Pharmacological regulation is also documented: micromolar disulfiram and its analogues inhibit Ins(1,4,5)P3 5-phosphatase, providing a chemical means to modulate the activity. In disease contexts, altered 5-phosphatase activity and subcellular distribution have been observed during hepatocarcinogenesis, indicating that regulation can be perturbed in cancer.
inositol-1,4,5-trisphosphate 5-phosphatase activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| INPP5A / 5-phosphatase | Uveal melanoma survival and calcium oscillations | Knockout and overexpression in uveal melanoma cell lines. |
| INPP5D (SHIP1) | Microglial inflammasome activation and neuroinflammation | Knockout and point-mutation knock-in in human microglia. |
| INPP5A / INPP5B | Hepatocarcinogenesis and altered Ins(1,4,5)P3 turnover | Knockout in liver cancer cell lines and activity assays. |
| ITPKA | Dendritic morphology and synaptic Ca2+ transients | Knockout and tagged knock-in in neurons. |
| INPP5D / INPPL1 | Phosphoinositide signaling in immune and metabolic cells | Overexpression and knockout in immune cell models. |
Uveal melanoma and oncogenic G protein signaling
In uveal melanoma, inositol (1,4,5)-trisphosphate 5-phosphatase promotes survival by regulating oncogenic G protein-driven calcium oscillations. This places GO:0052658 activity downstream of mutated GNAQ/GNA11 signaling and suggests that the enzyme helps maintain a calcium oscillation pattern favorable to tumor cell survival. Experimental models that manipulate 5-phosphatase levels or activity can test whether the calcium phenotype is causal for survival.
Microglial inflammasome activation and neuroinflammation
INPP5D, a 5-phosphatase family member, regulates inflammasome activation in human microglia. Because inflammasomes drive IL-1beta maturation and neuroinflammatory responses, this finding links GO:0052658 activity to innate immune control in the central nervous system. Microglial models with altered INPP5D expression or catalytic activity are useful for dissecting the signaling steps between phosphoinositide turnover and inflammasome output.
Hepatocarcinogenesis and altered Ins(1,4,5)P3 turnover
During hepatocarcinogenesis, the activities and subcellular distribution of Ins(1,4,5)P3 turnover enzymes, including 5-phosphatase, are altered. These changes may contribute to sustained calcium signaling or altered phosphoinositide homeostasis in liver cancer cells. Measuring 5-phosphatase activity in liver cancer models can clarify whether the alteration is a driver or a consequence of transformation.
Neurological function and synaptic calcium dynamics
The opposing enzyme ITPKA, an Ins(1,4,5)P3 3-kinase, regulates dendritic morphology and shapes synaptic Ca2+ transients. Because 5-phosphatase competes for the same substrate, changes in GO:0052658 activity are expected to influence neuronal calcium signaling and synaptic plasticity, although direct disease links require further study.
From inositol-1,4,5-trisphosphate 5-phosphatase activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of a specific 5-phosphatase alter Ins(1,4,5)P3 levels and Ca2+ oscillations? | CRISPR knockout cell line with live-cell Ca2+ imaging. |
| Is the catalytic activity required for a disease phenotype? | Point-mutation knock-in of a catalytically dead allele. |
| Where is the enzyme localized within the cell? | Tagged knock-in with fluorescent or affinity tag. |
| Does overexpression phenocopy or rescue a signaling defect? | Doxycycline-inducible overexpression cell model. |
| Which genes modify the 5-phosphatase-dependent phenotype? | CRISPR library screening with Ca2+ or survival readout. |
| Can pharmacological inhibition reproduce genetic loss of function? | Wild-type cells treated with disulfiram analogues. |
How to Study the inositol-1,4,5-trisphosphate 5-phosphatase activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Ins(1,4,5)P3 5-phosphatase activity assay | Conversion of Ins(1,4,5)P3 to Ins(1,4)P2 and phosphate | Direct biochemical measurement of GO:0052658. |
| Live-cell Ca2+ imaging | Cytosolic Ca2+ oscillations and transients | Functional readout of 5-phosphatase activity. |
| CRISPR knockout | Loss of enzyme expression and activity | Causal testing of specific 5-phosphatase genes. |
| Point-mutation knock-in | Catalytically dead or altered enzyme | Separating catalysis from scaffolding. |
| Tagged knock-in | Subcellular localization and interactions | Mapping where the activity occurs. |
| Overexpression | Gain-of-function effects on signaling | Rescue and phenocopy experiments. |
| RNA-seq | Transcriptional changes after perturbation | Pathway-level interpretation of 5-phosphatase loss. |
| Inhibitor treatment | Acute pharmacological inhibition | Comparing chemical and genetic inhibition. |
Measuring 5-phosphatase enzymatic activity
Biochemical assays that monitor conversion of Ins(1,4,5)P3 to Ins(1,4)P2 and phosphate are the direct way to measure GO:0052658 activity. Purification of native enzyme from brain tissue, as demonstrated for bovine brain Ins(1,4,5)P3 5-phosphatase, provides a positive control for activity assays. Inhibitor studies with disulfiram and analogues can confirm that the measured activity is sensitive to known 5-phosphatase inhibitors.
Live-cell calcium imaging
Because 5-phosphatase activity controls Ins(1,4,5)P3-dependent Ca2+ release, live-cell Ca2+ imaging is a functional readout of the activity. In uveal melanoma, calcium oscillations driven by oncogenic G proteins were used to show that 5-phosphatase promotes survival. Similar imaging in neurons can reveal changes in synaptic Ca2+ transients when 5-phosphatase or opposing 3-kinase activities are manipulated.
Genetic perturbation with CRISPR
CRISPR knockout, point-mutation knock-in and tagged knock-in allow causal testing of specific 5-phosphatase genes. Knockout removes the enzyme and reveals its contribution to Ins(1,4,5)P3 turnover, whereas catalytically dead knock-in separates catalytic activity from scaffolding functions. Tagged knock-in enables localization and interaction studies without overexpression artifacts.
Transcriptomics and phosphoinositide profiling
RNA-seq and phosphoinositide lipid profiling can place GO:0052658 activity in the broader context of phosphatidylinositol signaling reactions. In hepatocarcinogenesis, changes in Ins(1,4,5)P3 turnover enzyme activities and subcellular distribution were detected alongside transformation, illustrating how activity measurements can be combined with expression data. In microglia, inflammasome readouts complement phosphoinositide measurements to connect INPP5D to immune activation.
How CRISPR Can Be Used to Study GO:0052658 inositol-1,4,5-trisphosphate 5-phosphatase activity
Knockout
CRISPR knockout of a 5-phosphatase gene removes the enzyme and elevates Ins(1,4,5)P3, which can be read out by Ca2+ imaging or activity assays. Knockout models are essential for determining whether a specific gene accounts for the measured GO:0052658 activity in a given cell type. In uveal melanoma and microglia, knockout approaches can test the contribution of 5-phosphatase to survival and inflammasome activation, respectively.
Point Mutation
Point-mutation knock-in of catalytic residues can generate catalytically dead alleles while preserving protein expression and interactions. Such models distinguish the enzymatic activity of GO:0052658 from non-catalytic functions of the same protein, which is important because 5-phosphatases can also act as scaffolds. Comparing wild-type and catalytically dead knock-in cells in Ca2+ imaging or inflammasome assays provides a clean test of mechanism.
Knock-in
Tagged knock-in adds fluorescent or affinity tags to endogenous 5-phosphatase genes, enabling localization and interaction studies at physiological expression levels. This is particularly useful for enzymes with distinct subcellular distributions, as seen for Ins(1,4,5)P3 turnover enzymes in hepatocarcinogenesis. Tagged knock-in avoids the artifacts of overexpression and allows live-cell tracking of the enzyme.
Overexpression
Overexpression of a 5-phosphatase gene increases the capacity to degrade Ins(1,4,5)P3 and can suppress Ca2+ oscillations. Overexpression models are useful for rescue experiments and for testing whether increased activity is sufficient to change disease-relevant phenotypes such as melanoma survival. Inducible overexpression systems allow dose- and time-controlled experiments that complement constitutive knockout.
How EDITGENE Supports inositol-1,4,5-trisphosphate 5-phosphatase activity Research
Researchers studying inositol-1,4,5-trisphosphate 5-phosphatase activity-related genes often need to determine whether a candidate gene is causally involved in Ins(1,4,5)P3 turnover, calcium signaling or a disease phenotype, rather than merely correlated with it. This requires precise genetic models that isolate catalytic activity, localization and expression level, combined with functional readouts such as Ca2+ imaging and activity assays.
Contact EDITGENE today to design your custom CRISPR model for inositol-1,4,5-trisphosphate 5-phosphatase activity research.
Frequently Asked Questions About inositol-1,4,5-trisphosphate 5-phosphatase activity
What is inositol-1,4,5-trisphosphate 5-phosphatase activity?
It is the enzymatic activity defined by GO:0052658 that catalyzes the reaction 1D-myo-inositol 1,4,5-trisphosphate + H2O = 1D-myo-inositol 1,4-bisphosphate + phosphate, thereby terminating the calcium-mobilizing signal of Ins(1,4,5)P3.
What genes are involved in inositol-1,4,5-trisphosphate 5-phosphatase activity?
Genes encoding 5-phosphatases include INPP5A, INPP5B, INPP5D (SHIP1), INPPL1 (SHIP2), OCRL, INPP5E, INPP5J, INPP5K and SACM1L, which differ in substrate specificity and localization.
How does 5-phosphatase activity affect calcium signaling?
By removing the 5-phosphate from Ins(1,4,5)P3, the enzyme lowers the pool available to open Ins(1,4,5)P3 receptors, which shortens or suppresses Ca2+ oscillations.
What is the difference between Ins(1,4,5)P3 3-kinase and 5-phosphatase?
3-kinase phosphorylates Ins(1,4,5)P3 to Ins(1,3,4,5)P4, while 5-phosphatase dephosphorylates it to Ins(1,4)P2; the balance between these activities shapes Ca2+ oscillation patterns.
Is inositol-1,4,5-trisphosphate 5-phosphatase involved in cancer?
Yes, in uveal melanoma the activity promotes survival by regulating oncogenic G protein-driven calcium oscillations, and altered Ins(1,4,5)P3 turnover occurs in hepatocarcinogenesis.
Can 5-phosphatase activity be inhibited pharmacologically?
Micromolar concentrations of disulfiram and its analogues inhibit inositol 1,4,5-trisphosphate 5-phosphatase, providing a chemical tool to modulate the activity.
How do I measure inositol-1,4,5-trisphosphate 5-phosphatase activity in the lab?
Direct biochemical assays monitor conversion of Ins(1,4,5)P3 to Ins(1,4)P2 and phosphate, while live-cell Ca2+ imaging provides a functional readout of the activity.
What diseases are linked to INPP5D 5-phosphatase activity?
INPP5D regulates inflammasome activation in human microglia, linking the activity to neuroinflammatory processes.
Which CRISPR model is best for studying 5-phosphatase function?
Knockout is best for removing activity, point-mutation knock-in separates catalysis from scaffolding, tagged knock-in reveals localization, and overexpression tests gain of function.
Why is GO:0052658 important for drug discovery?
Because the activity controls Ins(1,4,5)P3 lifetime and Ca2+ signaling, and because inhibitors such as disulfiram analogues exist, it is a tractable node for pharmacological intervention in cancer and immune signaling.
Conclusion
GO:0052658, inositol-1,4,5-trisphosphate 5-phosphatase activity, is a central off-switch in phosphoinositide calcium signaling. It converts Ins(1,4,5)P3 to Ins(1,4)P2, thereby shaping Ca2+ oscillation dynamics and influencing processes ranging from melanoma survival to microglial inflammasome activation. The activity is carried by a family of 5-phosphatases with distinct localizations and substrate preferences, and it can be modulated pharmacologically by disulfiram analogues. For researchers, precise genetic models are essential to move from correlation to causation. CRISPR knockout, point-mutation knock-in, tagged knock-in and overexpression, combined with activity assays and live-cell Ca2+ imaging, provide a rigorous framework for dissecting how individual 5-phosphatases contribute to normal physiology and disease.
References
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- 5. Fowler CJ et al.. 1993. Inhibition of inositol 1,4,5-trisphosphate 5-phosphatase by micromolar concentrations of disulfiram and its analogues.. Biochem J 289 ( Pt 3)(Pt 3):853-9 PMID: 8382055
- 6. Verjans B et al.. 1992. Purification of bovine brain inositol-1,4,5-trisphosphate 5-phosphatase.. Eur J Biochem 204(3):1083-7 PMID: 1312931
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