GO:0046934 1-phosphatidylinositol-4,5-bisphosphate 3-kinase activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0046934 describes the catalytic conversion of 1-phosphatidyl-1D-myo-inositol 4,5-bisphosphate (PIP2) to 1-phosphatidyl-1D-myo-inositol 3,4,5-trisphosphate (PIP3) using ATP.
• This activity is the defining biochemical function of class I, class II, and class III phosphoinositide 3-kinases (PI3Ks).
• PIP3 produced by this reaction acts as a second messenger that recruits signaling proteins to membranes, influencing cell survival, proliferation, and autophagy.
• Dysregulation of this activity is implicated in cancer, metabolic disorders, and immune responses.
• Experimental models for studying this activity include knockout, point-mutation, and overexpression cell lines, as well as CRISPR library screening.
• Network pharmacology and molecular docking studies have identified natural compounds that may modulate this activity in chronic kidney disease.
Description
The enzyme activity defined by GO:0046934, 1-phosphatidylinositol-4,5-bisphosphate 3-kinase activity, is a central node in phosphoinositide signaling. It catalyzes the phosphorylation of PIP2 at the D3 position of the inositol ring to generate PIP3, a lipid second messenger that orchestrates diverse cellular responses. This activity is attributed to the PI3K family of enzymes, which are classified into classes I, II, and III based on structure and substrate specificity. Researchers study this activity to understand how cells transduce signals from growth factors, hormones, and immune receptors into changes in metabolism, survival, and gene expression. The importance of GO:0046934 extends to human disease. Aberrant activation of PI3K signaling is a hallmark of many cancers, where it drives uncontrolled proliferation and resistance to apoptosis. In bladder cancer, tumor-infiltrating M2 macrophages driven by specific genomic alterations are associated with prognosis, highlighting the role of PI3K-dependent immune modulation. In lung cancer, compounds such as prodigiosin can elicit autophagic cell death through a PI3K/Beclin-1-independent pathway, underscoring the complexity of PI3K-related autophagy regulation. Beyond oncology, this activity is implicated in metabolic dysfunction and kidney disease. For example, d-allulose ameliorates metabolic dysfunction in diabetic mice, potentially through pathways involving PI3K signaling. Network pharmacology studies of Yishenqingzhuo oral liquid for chronic kidney disease have identified PI3K-related targets, suggesting therapeutic potential. Thus, GO:0046934 is a critical molecular function for both basic cell biology and translational research.
1-phosphatidylinositol-4,5-bisphosphate 3-kinase activity At A Glance
| GO ID | GO:0046934 |
|---|---|
| GO term | 1-phosphatidylinositol-4,5-bisphosphate 3-kinase activity |
| Ontology | molecular_function |
| Synonym | phosphatidylinositol 3-kinase activity, class I; phosphatidylinositol 3-kinase activity, class II; phosphatidylinositol 3-kinase, class I; catalyst activity; phosphatidylinositol-4,5-bisphosphate 3-kinase activity; type I phosphoinositide 3-kinase activity |
| Definition | Catalysis of the reaction: a 1-phosphatidyl-1D-myo-inositol 4,5-bisphosphate + ATP = a 1-phosphatidyl-1D-myo-inositol 3,4,5-trisphosphate + ADP + H+. |
| Major function | Phosphorylation of PIP2 to generate PIP3, a key lipid second messenger. |
| Reaction direction | Forward: PIP2 + ATP -> PIP3 + ADP + H+ |
| Substrates | 1-phosphatidyl-1D-myo-inositol 4,5-bisphosphate (PIP2) and ATP |
| Products | 1-phosphatidyl-1D-myo-inositol 3,4,5-trisphosphate (PIP3), ADP, and H+ |
What Is GO:0046934?
In simple terms, GO:0046934 is the enzyme activity that adds a phosphate group to a specific lipid (PIP2) to create PIP3. According to QuickGO, it catalyzes the reaction: a 1-phosphatidyl-1D-myo-inositol 4,5-bisphosphate + ATP = a 1-phosphatidyl-1D-myo-inositol 3,4,5-trisphosphate + ADP + H+. This activity is synonymous with phosphatidylinositol 3-kinase activity (class I and class II) and type I phosphoinositide 3-kinase activity. It is a molecular_function in the Gene Ontology, meaning it describes what a gene product does at the biochemical level.
Why Is 1-phosphatidylinositol-4,5-bisphosphate 3-kinase activity Important in Cell Biology?
GO:0046934 is important because it represents the first committed step in the PI3K signaling pathway, which controls fundamental cellular processes such as growth, survival, proliferation, and autophagy. The product PIP3 serves as a docking site for proteins containing pleckstrin homology (PH) domains, including AKT and PDK1, thereby propagating signals that influence metabolism and gene expression. Dysregulation of this activity is linked to cancer, metabolic disorders, and immune dysfunction, making it a prime target for therapeutic intervention.
• Central to cell survival and proliferation through AKT activation.
• Regulates autophagy in cancer cells, as shown in lung cancer models.
• Modulates immune responses, including macrophage polarization in bladder cancer.
• Involved in metabolic dysfunction, with potential links to d-allulose effects in diabetic mice.
• Implicated in chronic kidney disease, as identified by network pharmacology of Yishenqingzhuo oral liquid.
• Target for anticancer drug discovery, given its role in tumor progression.
• Participates in angiogenesis and cardioprotection, as suggested by cardio-omentopexy studies.
• Essential for understanding phosphoinositide signaling in health and disease.
• Provides a biochemical marker for PI3K pathway activation in research and diagnostics.
• Enables CRISPR-based functional genomics to dissect gene-disease relationships.
What Happens During 1-phosphatidylinositol-4,5-bisphosphate 3-kinase activity?
Substrate Binding and Catalysis
In simple terms: The enzyme grabs PIP2 and ATP, then transfers a phosphate from ATP to PIP2.
The catalytic mechanism of GO:0046934 involves the binding of the substrate 1-phosphatidyl-1D-myo-inositol 4,5-bisphosphate (PIP2) and ATP to the active site of the PI3K enzyme. The enzyme catalyzes the transfer of the gamma-phosphate of ATP to the D3 position of the inositol ring, producing 1-phosphatidyl-1D-myo-inositol 3,4,5-trisphosphate (PIP3), ADP, and a proton. This reaction is highly specific for the D3 position and requires magnesium ions as cofactors.
Product Formation and Membrane Recruitment
In simple terms: The new lipid PIP3 stays in the membrane and recruits signaling proteins.
The product PIP3 remains in the plasma membrane and acts as a docking site for proteins with pleckstrin homology (PH) domains, such as AKT and PDK1. This recruitment initiates downstream signaling cascades that regulate cell survival, proliferation, and metabolism. The generation of PIP3 is transient and tightly regulated by phosphatases such as PTEN, which converts PIP3 back to PIP2.
Downstream Signaling and Cellular Outcomes
In simple terms: PIP3 triggers a chain of signals that tell the cell to grow, survive, or recycle components.
Once PIP3 is produced, it activates AKT and other effectors, leading to diverse cellular outcomes including inhibition of apoptosis, promotion of cell cycle progression, and modulation of autophagy. In lung cancer, prodigiosin can induce autophagic cell death through a PI3K/Beclin-1-independent pathway, indicating that PI3K activity can influence autophagy in complex ways. In bladder cancer, PI3K signaling in tumor-infiltrating M2 macrophages is associated with prognosis, linking this activity to immune evasion.
Regulation by PTEN and Other Phosphatases
In simple terms: Other enzymes can reverse the reaction to keep signaling in check.
The activity of GO:0046934 is counterbalanced by lipid phosphatases, most notably PTEN, which dephosphorylates PIP3 at the D3 position to regenerate PIP2. This balance is crucial for preventing excessive signaling. Loss of PTEN function leads to constitutive PIP3 accumulation and hyperactivation of downstream pathways, a common event in cancer. Other phosphatases, such as SHIP, can also modulate PIP3 levels by removing the 5-phosphate.
Integration with Other Signaling Pathways
In simple terms: PI3K signaling talks to other pathways to fine-tune cell decisions.
GO:0046934 is not an isolated reaction; it integrates with other signaling networks, including the mTOR pathway, which senses nutrients and energy status. In chronic kidney disease, network pharmacology has identified PI3K-related targets for Yishenqingzhuo oral liquid, suggesting crosstalk with inflammatory and fibrotic pathways. Similarly, d-allulose ameliorates metabolic dysfunction in diabetic mice, potentially through PI3K-dependent mechanisms. Cardio-omentopexy studies in mice indicate that PI3K activity may contribute to myocardial angiogenesis and cardioprotection.
Key Genes Involved in GO:0046934 1-phosphatidylinositol-4,5-bisphosphate 3-kinase activity
The following genes encode proteins that possess or regulate 1-phosphatidylinositol-4,5-bisphosphate 3-kinase activity (GO:0046934).
| Gene | Major Role | Research Relevance |
|---|---|---|
| PIK3CA | Catalytic subunit of class I PI3K alpha | Frequently mutated in cancers; target for inhibitors |
| PIK3CB | Catalytic subunit of class I PI3K beta | Implicated in metabolic signaling and cancer |
| PIK3CD | Catalytic subunit of class I PI3K delta | Key in immune cell signaling; target for immunomodulation |
| PIK3CG | Catalytic subunit of class I PI3K gamma | Involved in inflammation and immune responses |
| PIK3R1 | Regulatory subunit p85 alpha of class I PI3K | Mutations affect PI3K activity in cancer and diabetes |
| PIK3R2 | Regulatory subunit p85 beta | Modulates PI3K signaling in development |
| PIK3C2A | Class II PI3K alpha | Role in endocytosis and autophagy |
| PIK3C2B | Class II PI3K beta | Implicated in cell migration |
| PIK3C3 | Class III PI3K (Vps34) | Essential for autophagy and vesicle trafficking |
| PTEN | Lipid phosphatase that reverses PI3K activity | Tumor suppressor; loss leads to PIP3 accumulation |
| AKT1 | Downstream effector of PIP3 | Mediates survival and proliferation signals |
| PDK1 | Kinase activated by PIP3 | Phosphorylates AKT and other AGC kinases |
| MTOR | Kinase in PI3K-related pathway | Integrates nutrient and growth signals |
| BECN1 | Autophagy regulator interacting with PI3K | Modulates autophagic cell death in cancer |
| RPTOR | Component of mTORC1 | Links PI3K signaling to protein synthesis |
| TSC1 | Tumor suppressor upstream of mTOR | Regulates PI3K-AKT-mTOR axis |
| TSC2 | Tumor suppressor upstream of mTOR | Mutations cause tuberous sclerosis; interacts with PI3K |
| RHEB | Activator of mTORC1 | Connects PI3K signaling to growth control |
How Is 1-phosphatidylinositol-4,5-bisphosphate 3-kinase activity Regulated?
The activity of GO:0046934 is regulated at multiple levels. Class I PI3Ks are activated by receptor tyrosine kinases and G-protein-coupled receptors, which recruit the enzyme to the membrane and relieve inhibition by regulatory subunits. PTEN acts as a major negative regulator by dephosphorylating PIP3. Additionally, mTOR, a downstream effector, participates in feedback loops that modulate PI3K signaling. In disease contexts, such as chronic kidney disease, network pharmacology has identified PI3K as a target of Yishenqingzhuo oral liquid, suggesting that natural compounds can modulate this activity.
1-phosphatidylinositol-4,5-bisphosphate 3-kinase activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| PIK3CA | Cancer (e.g., breast, bladder) | Knockout or point-mutation cell lines |
| PTEN | Cancer, metabolic disorders | Knockout models to study PIP3 accumulation |
| PIK3CD | Immune disorders | Overexpression or knockout in immune cells |
| PIK3C3 | Autophagy-related diseases | Knockout for autophagy studies |
| AKT1 | Cancer, diabetes | Point-mutation knock-in to study activation |
Cancer
Dysregulation of GO:0046934 is a hallmark of many cancers. Activating mutations in PIK3CA, the gene encoding the catalytic subunit of PI3K alpha, lead to constitutive PIP3 production and uncontrolled cell growth. In bladder cancer, tumor-infiltrating M2 macrophages driven by specific genomic alterations are associated with prognosis, highlighting the role of PI3K signaling in the tumor microenvironment. In lung cancer, prodigiosin induces autophagic cell death through a PI3K/Beclin-1-independent pathway, demonstrating the complexity of targeting this activity.
Metabolic Disorders
PI3K signaling is critical for insulin sensitivity and glucose homeostasis. In diabetic mice, d-allulose ameliorates metabolic dysfunction, potentially through pathways involving PI3K. This suggests that modulating GO:0046934 activity could have therapeutic benefits in metabolic diseases.
Kidney Disease
Network pharmacology and molecular docking studies of Yishenqingzhuo oral liquid for chronic kidney disease have identified PI3K-related targets, indicating that this activity contributes to renal pathology and may be a therapeutic target.
Cardiovascular Biology
Cardio-omentopexy requires a cardioprotective innate immune response to promote myocardial angiogenesis in mice, a process in which PI3K signaling may play a role. This links GO:0046934 to cardiac repair and angiogenesis.
From 1-phosphatidylinositol-4,5-bisphosphate 3-kinase activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of PIK3CA reduce PIP3 levels? | PIK3CA knockout cell line |
| Does a specific mutation activate PI3K signaling? | Point-mutation knock-in of PIK3CA |
| Can a tagged PI3K protein be used for imaging? | Knock-in of fluorescent tag |
| Does overexpression of PIK3CB drive proliferation? | Overexpression cell line |
| Which genes modulate PI3K activity? | CRISPR library screening |
| How does PTEN loss affect PIP3 dynamics? | PTEN knockout model |
How to Study the 1-phosphatidylinositol-4,5-bisphosphate 3-kinase activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Lipid kinase assay | PIP3 production from PIP2 | Direct measurement of GO:0046934 activity |
| PH domain biosensor imaging | Intracellular PIP3 localization | Live-cell dynamics of PI3K signaling |
| CRISPR knockout screen | Gene requirements for PI3K activity | Discovery of novel regulators |
| Phosphoproteomics | Phosphorylation of downstream effectors | Pathway activation profiling |
| Western blot | AKT phosphorylation status | Routine assessment of PI3K pathway |
| qPCR | Expression of PI3K genes | Transcriptional regulation studies |
| Molecular docking | Compound binding to PI3K | Drug discovery and repurposing |
| Network pharmacology | Target identification in disease | Systems-level analysis of PI3K in disease |
Lipid Kinase Assays
In vitro kinase assays using recombinant PI3K and PIP2 substrate measure the catalytic activity of GO:0046934 directly. These assays typically use radiolabeled ATP and thin-layer chromatography to detect PIP3 formation.
Live-Cell Imaging of PIP3
Genetically encoded biosensors, such as GFP-tagged PH domains, allow real-time visualization of PIP3 production in living cells. This method reveals spatiotemporal dynamics of GO:0046934 activity.
CRISPR Screening
Genome-wide CRISPR knockout or activation screens can identify genes that regulate PI3K signaling. These screens are powerful for discovering novel modulators of GO:0046934.
Phosphoproteomics
Mass spectrometry-based phosphoproteomics quantifies downstream phosphorylation events triggered by PI3K activity, such as AKT phosphorylation. This provides a systems-level view of signaling outcomes.
How CRISPR Can Be Used to Study GO:0046934 1-phosphatidylinositol-4,5-bisphosphate 3-kinase activity
Knockout
CRISPR knockout of PIK3CA, PIK3CB, or other PI3K genes eliminates GO:0046934 activity, allowing researchers to study loss-of-function phenotypes such as reduced PIP3 levels and impaired AKT signaling.
Point Mutation
Point mutations can be introduced to mimic cancer-associated activating mutations (e.g., PIK3CA H1047R) or to abrogate catalytic activity. These models help dissect the specific contribution of GO:0046934 to cellular transformation.
Knock-in
Knock-in of epitope tags or fluorescent proteins into endogenous PI3K loci enables visualization and purification of the enzyme without altering its regulation. This is useful for studying localization and interaction partners.
Overexpression
Overexpression of wild-type or mutant PI3K subunits can amplify GO:0046934 activity, creating models of hyperactive signaling to study downstream effects and test inhibitors.
How EDITGENE Supports 1-phosphatidylinositol-4,5-bisphosphate 3-kinase activity Research
Researchers studying 1-phosphatidylinositol-4,5-bisphosphate 3-kinase activity-related genes often need to determine whether a candidate gene is causally involved in a specific phenotype, such as cancer cell proliferation or metabolic dysfunction. EDITGENE provides comprehensive CRISPR-based services to generate precisely engineered cell models for such investigations.
Contact EDITGENE today to design your custom CRISPR model for 1-phosphatidylinositol-4,5-bisphosphate 3-kinase activity research.
Frequently Asked Questions About 1-phosphatidylinositol-4,5-bisphosphate 3-kinase activity
What is 1-phosphatidylinositol-4,5-bisphosphate 3-kinase activity?
It is the enzyme activity (GO:0046934) that phosphorylates PIP2 to produce PIP3, a key lipid second messenger, using ATP.
What genes are involved in 1-phosphatidylinositol-4,5-bisphosphate 3-kinase activity?
Genes include PIK3CA, PIK3CB, PIK3CD, PIK3CG, PIK3R1, PIK3C3, and PTEN, among others.
How is GO:0046934 regulated?
It is regulated by receptor tyrosine kinases, G-protein-coupled receptors, and phosphatases like PTEN.
What diseases are associated with PI3K activity?
Cancer, metabolic disorders, kidney disease, and cardiovascular conditions.
What is the reaction catalyzed by GO:0046934?
PIP2 + ATP -> PIP3 + ADP + H+.
How can I study PI3K activity in the lab?
Use lipid kinase assays, live-cell imaging with PH domain biosensors, CRISPR screens, and phosphoproteomics.
What are the synonyms for GO:0046934?
Phosphatidylinositol 3-kinase activity (class I and II), type I phosphoinositide 3-kinase activity, and others.
Which CRISPR model is best for studying PI3K mutations?
Point-mutation knock-in models are ideal for mimicking cancer-associated mutations like PIK3CA H1047R.
Can PI3K activity be targeted therapeutically?
Yes, inhibitors of PI3K are in clinical trials for cancer and other diseases.
What is the role of PTEN in PI3K signaling?
PTEN dephosphorylates PIP3 to PIP2, acting as a negative regulator of GO:0046934.
Conclusion
GO:0046934, 1-phosphatidylinositol-4,5-bisphosphate 3-kinase activity, is a fundamental molecular function that governs cell survival, proliferation, and metabolism through the production of PIP3. Its dysregulation is implicated in cancer, metabolic disorders, and kidney disease, making it a prime target for therapeutic intervention. Understanding its mechanism and regulation is essential for developing targeted therapies and precision medicine approaches.
References
- 1. Lee D et al.. 2020. d-allulose Ameliorates Metabolic Dysfunction in C57BL/KsJ-db/db Mice.. Molecules 25(16) PMID: 32796637
- 2. Xue Y et al.. 2019. Tumor‑infiltrating M2 macrophages driven by specific genomic alterations are associated with prognosis in bladder cancer.. Oncol Rep 42(2):581-594 PMID: 31233191
- 3. Ge ZD et al.. 2022. Cardio-omentopexy requires a cardioprotective innate immune response to promote myocardial angiogenesis in mice.. JTCVS Open 10:222-242 PMID: 36004249
- 4. Chiu WJ et al.. 2018. Prodigiosin-Emerged PI3K/Beclin-1-Independent Pathway Elicits Autophagic Cell Death in Doxorubicin-Sensitive and -Resistant Lung Cancer.. J Clin Med 7(10) PMID: 30282915
- 5. Zhao A et al.. 2025. Network pharmacology and molecular docking analysis of Yishenqingzhuo oral liquid for chronic kidney disease.. Medicine (Baltimore) 104(47):e46030 PMID: 41305835
