GO:0005547 phosphatidylinositol-3,4,5-trisphosphate binding: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0005547 (phosphatidylinositol-3,4,5-trisphosphate binding) describes the molecular function of selectively binding PIP3, a membrane lipid phosphorylated at the 3', 4' and 5' positions of the inositol ring.
• PIP3 binding is mediated by pleckstrin homology (PH) domains and other lipid-binding modules that decode PIP3 signals at membranes and in the nucleus.
• PIP3 binding proteins act as effectors and scaffolds that control cell signaling, membrane trafficking, phagocytosis and epithelial polarity.
• The PIP3 interactome has been mapped by affinity proteomics, revealing hundreds of candidate binders including nucleolar and cytoskeletal proteins.
• Optogenetic and vacuolar PIP3 tools show that PIP3 binding can be manipulated in living cells to probe membrane microdomain assembly and fusion.
• CRISPR knockout, point-mutation, knock-in and overexpression models are essential to test whether a PIP3-binding protein is causally involved in a phenotype.
Description
Phosphatidylinositol-3,4,5-trisphosphate (PIP3) is a low-abundance membrane phospholipid generated by phosphoinositide 3-kinases, and it serves as a docking site for signaling proteins that contain PIP3-binding modules. The Gene Ontology molecular function GO:0005547, phosphatidylinositol-3,4,5-trisphosphate binding, defines the selective interaction of a protein with PIP3, a derivative of phosphatidylinositol phosphorylated at the 3', 4' and 5' positions of the inositol ring. This function is central to signal transduction because PIP3 binding recruits effectors to membranes and nucleolar compartments, thereby converting lipid second messengers into cellular responses. Researchers study GO:0005547 to understand how cells decode PIP3 signals during growth, motility, phagocytosis, membrane fusion and epithelial polarization. Affinity proteomics has identified a broad PIP3 interactome, including pleckstrin homology (PH) domain proteins, nucleolar proteins and cytoskeletal regulators. Functional studies show that PIP3 binding directs association of Src homology 2-containing signaling proteins with gelsolin and regulates basolateral membrane formation in epithelial cells. Because PIP3 binding is dynamic and compartment-specific, its investigation requires tools that can detect, localize and perturb the interaction in living cells. Optogenetic PIP3 tools and vacuolar PIP3 probes have been developed to control membrane microdomain assembly and fusion, illustrating how the function can be dissected experimentally. This article summarizes the definition, mechanisms, key genes, disease links and research methods for GO:0005547, with a focus on CRISPR-based models for causal testing.
phosphatidylinositol-3,4,5-trisphosphate binding At A Glance
| GO ID | GO:0005547 |
|---|---|
| GO term | phosphatidylinositol-3,4,5-trisphosphate binding |
| Ontology | molecular_function |
| Synonym | PIP3 binding |
| Major function | Selective binding of proteins to phosphatidylinositol-3,4,5-trisphosphate (PIP3) at membranes and in the nucleus |
| Definition source | QuickGO definition: binding to phosphatidylinositol-3,4,5-trisphosphate, a derivative of phosphatidylinositol phosphorylated at the 3', 4' and 5' positions |
| Common domains | Pleckstrin homology (PH) domains and other lipid-binding modules |
| Cellular contexts | Plasma membrane, endomembranes, vacuole and nucleolus |
| Representative processes | Cell signaling, phagocytosis, membrane fusion, epithelial polarity |
What Is GO:0005547?
GO:0005547 phosphatidylinositol-3,4,5-trisphosphate binding is the molecular function of binding to phosphatidylinositol-3,4,5-trisphosphate, a derivative of phosphatidylinositol in which the inositol ring is phosphorylated at the 3', 4' and 5' positions. The synonym PIP3 binding is commonly used. This function is mediated by lipid-binding domains such as PH domains and is distinct from binding to other phosphoinositides because it requires the 3', 4' and 5' phosphates.
Why Is phosphatidylinositol-3,4,5-trisphosphate binding Important in Cell Biology?
GO:0005547 is important because PIP3 binding is a primary mechanism by which cells convert the lipid second messenger PIP3 into specific biological outputs, including activation of signaling complexes, phagocytosis, membrane fusion and establishment of epithelial polarity. The PIP3 interactome is enriched in nucleolar proteins, indicating that PIP3 binding also operates in nuclear and nucleolar compartments beyond the plasma membrane. Because PIP3 binding proteins are frequently deregulated in disease, understanding this function supports target discovery and the design of CRISPR models to test causality.
• PIP3 binding recruits signaling effectors to membranes, linking phosphoinositide 3-kinase activity to downstream responses.
• It directs association of Src homology 2-containing signaling proteins with gelsolin, connecting PIP3 to actin regulation.
• PIP3 binding regulates formation of the basolateral plasma membrane in epithelial cells, a key polarity process.
• It induces phagocytosis of nonmotile Pseudomonas aeruginosa, showing a role in host defense.
• Vacuolar PIP3 binding to Vam7 controls fusion through membrane microdomain assembly.
• Nuclear PIP3 binding is enriched in nucleolar proteins, expanding the functional repertoire beyond the plasma membrane.
• Optogenetic PIP3 tools enable precise manipulation of PIP3-dependent membrane dynamics.
• Affinity proteomics has defined a broad PIP3 interactome, providing candidate genes for functional studies.
• Deregulated PIP3 binding contributes to cancer, immune dysfunction and membrane trafficking disorders.
• CRISPR models allow causal testing of PIP3-binding proteins in disease-relevant phenotypes.
Molecular Mechanism of phosphatidylinositol-3,4,5-trisphosphate binding
Recognition of the PIP3 headgroup
In simple terms: Proteins bind PIP3 by recognizing its uniquely phosphorylated inositol headgroup.
PIP3 is a phosphatidylinositol derivative phosphorylated at the 3', 4' and 5' positions of the inositol ring, and this specific phosphorylation pattern is required for selective binding by PIP3-binding proteins. Pleckstrin homology (PH) domains and other lipid-binding modules form electrostatic and hydrogen-bonding interactions with the PIP3 headgroup, allowing proteins to discriminate PIP3 from other phosphoinositides. The PIP3 interactome is enriched in proteins with such modules, including nucleolar proteins, indicating that headgroup recognition occurs in multiple cellular compartments.
Membrane recruitment and microdomain assembly
In simple terms: Once bound to PIP3, proteins are pulled to membranes where they assemble signaling platforms.
Binding to PIP3 recruits proteins to membranes and promotes assembly of membrane microdomains. Vacuolar PIP3 controls fusion through binding Vam7 and membrane microdomain assembly, demonstrating that PIP3 binding can organize fusion-competent domains. Optogenetic tools that generate PIP3 locally induce membrane dynamics, confirming that PIP3 binding is sufficient to trigger membrane remodeling. In epithelial cells, PIP3 binding regulates formation of the basolateral plasma membrane, linking lipid recognition to membrane domain identity.
Effector activation and cytoskeletal coupling
In simple terms: PIP3 binding can switch on signaling proteins and connect them to the cytoskeleton.
PIP3 binding directs association of Src homology 2-containing signaling proteins with gelsolin, coupling lipid recognition to actin filament regulation. This effector coupling allows PIP3 binding to influence cell shape, motility and phagocytosis. PIP3 binding induces phagocytosis of nonmotile Pseudomonas aeruginosa, showing that the function can drive actin-dependent uptake of bacteria. Together, these examples illustrate how PIP3 binding translates lipid signals into mechanical and signaling outputs.
Nuclear and nucleolar PIP3 binding
In simple terms: PIP3 binding also happens inside the nucleus, especially in nucleoli.
The nuclear PIP3 interactome is enriched in nucleolar proteins, revealing that PIP3 binding is not restricted to the plasma membrane. This nuclear pool of PIP3 binders suggests roles in ribosome biogenesis, nucleolar organization and nuclear signaling. The existence of distinct nuclear and cytoplasmic PIP3-binding complexes implies that the same molecular function can be deployed in different compartments with different partners.
Regulation by PIP3 levels and competing phosphoinositides
In simple terms: PIP3 binding is controlled by how much PIP3 is present and by competing lipids.
Because PIP3 binding depends on the availability of PIP3, enzymes that synthesize or degrade PIP3 regulate the function indirectly. The PIP3 interactome contains many proteins that compete for the same lipid, and binding specificity is determined by the phosphorylation pattern of the inositol ring. Optogenetic production of PIP3 can override endogenous regulation and drive membrane dynamics, showing that local PIP3 concentration is a key determinant of binding. In vacuoles, PIP3 binding to Vam7 is required for fusion, indicating that compartment-specific PIP3 pools regulate distinct binding events.
Key Genes Involved in GO:0005547 phosphatidylinositol-3,4,5-trisphosphate binding
The following genes and proteins represent major PIP3-binding modules and effectors that are experimentally linked to GO:0005547.
| Gene | Major Role | Research Relevance |
|---|---|---|
| VAM7 | Vacuolar PIP3-binding protein required for fusion and membrane microdomain assembly | Model for vacuolar fusion and microdomain assembly |
| GSN | Gelsolin binds PIP3 and associates with Src homology 2-containing signaling proteins | Links PIP3 binding to actin regulation |
| SRC | Src homology 2-containing signaling protein recruited via PIP3 to gelsolin | Effector coupling to cytoskeleton |
| AKT1 | PIP3-binding effector in cell signaling | Central node in PIP3-dependent signaling |
| PLEK | Pleckstrin homology domain protein used as a PIP3-binding module | Affinity probe for PIP3 interactome |
| BTK | PH domain protein that binds PIP3 in signaling | Model for PH domain-lipid recognition |
| ARF6 | Regulates basolateral membrane formation with PIP3 | Epithelial polarity model |
| RAC1 | Cytoskeletal regulator downstream of PIP3 binding | Phagocytosis model |
| NPM1 | Nucleolar protein enriched in nuclear PIP3 interactome | Nucleolar PIP3 binding model |
| NCL | Nucleolar protein candidate in PIP3 interactome | Nuclear PIP3 function |
| VPS34 | Generates PIP3-related phosphoinositides for binding events | Upstream regulator of PIP3 binding |
| PTEN | Lipid phosphatase that removes PIP3 and limits binding | Negative regulator of PIP3 binding |
| PIK3CA | Kinase that produces PIP3 for binding | Upstream activator of PIP3 binding |
| VAMP7 | Fusion machinery component in vacuolar PIP3-dependent fusion | Fusion model |
| YPT7 | Vacuolar GTPase cooperating with PIP3 binding in fusion | Fusion regulation |
| PLD1 | Phospholipase linked to PIP3-dependent membrane dynamics | Optogenetic membrane dynamics |
| CDC42 | Polarity regulator coupled to PIP3-dependent membrane identity | Epithelial polarity |
How Is phosphatidylinositol-3,4,5-trisphosphate binding Regulated?
PIP3 binding is regulated by the balance of PIP3 synthesis and degradation, because the function depends on the presence of the lipid ligand. Phosphoinositide 3-kinases such as PIK3CA generate PIP3, while PTEN removes the 3-phosphate and terminates binding. Compartment-specific pools of PIP3, including vacuolar and nuclear pools, further restrict where binding occurs. Optogenetic production of PIP3 can locally activate binding and membrane dynamics, showing that spatial control of PIP3 is a key regulatory layer.
phosphatidylinositol-3,4,5-trisphosphate binding and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| AKT1 | Cancer signaling downstream of PIP3 binding | Point-mutation knock-in of PH domain |
| PTEN | Cancer predisposition via increased PIP3 binding | Knockout and overexpression |
| GSN | Cytoskeletal regulation in cancer and motility | Knockout with PIP3-binding mutant rescue |
| ARF6 | Epithelial polarity and membrane identity | Knockout in epithelial cells |
| VAM7 | Vacuolar fusion and trafficking | Knockout and tagged knock-in |
Cancer signaling
PIP3 binding is a core step in oncogenic phosphoinositide 3-kinase signaling, and proteins that bind PIP3, such as AKT1, are central effectors in cancer. Loss of PTEN increases PIP3 levels and enhances PIP3 binding, promoting survival and proliferation. Because PIP3 binding directs association of signaling proteins with cytoskeletal regulators like gelsolin, it also contributes to invasion and motility.
Infection and host defense
PIP3 binding induces phagocytosis of nonmotile Pseudomonas aeruginosa, linking this molecular function to bacterial clearance. Defects in PIP3-dependent phagocytosis could impair innate immunity, making PIP3-binding proteins candidate host factors in infection. The involvement of Rac1 and actin machinery further supports a role in immune cell engulfment.
Epithelial polarity and tissue architecture
PIP3 binding regulates formation of the basolateral plasma membrane in epithelial cells, a process essential for tissue organization. Disruption of PIP3 binding can alter membrane domain identity and contribute to polarity-related diseases. ARF6 and CDC42 cooperate in this PIP3-dependent polarity program.
Membrane trafficking and fusion disorders
Vacuolar PIP3 binding to Vam7 controls fusion through membrane microdomain assembly, and defects in this process can impair lysosomal and vacuolar function. Optogenetic studies show that PIP3 binding is sufficient to drive membrane dynamics, underscoring its importance in trafficking. Dysregulated membrane fusion is relevant to lysosomal storage and neurodegenerative conditions.
From phosphatidylinositol-3,4,5-trisphosphate binding-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Is a candidate gene required for PIP3 binding? | CRISPR knockout followed by PIP3 affinity pull-down |
| Does a specific residue mediate PIP3 binding? | Point-mutation knock-in of the lipid-binding domain |
| Where does the protein bind PIP3 in cells? | Tagged knock-in with fluorescent PIP3 reporter |
| Can PIP3 binding be enhanced or inhibited? | Overexpression of wild-type and mutant alleles |
| Does PIP3 binding drive membrane fusion? | Knockout with vacuolar fusion assays |
| Does PIP3 binding control epithelial polarity? | Knockout in polarized epithelial cells |
How to Study the phosphatidylinositol-3,4,5-trisphosphate binding Process
| Method | What It Measures | Typical Application |
|---|---|---|
| PIP3 affinity proteomics | Proteins that bind PIP3 | Interactome discovery |
| Nuclear PIP3 interactome | Nucleolar and nuclear PIP3 binders | Compartment-specific binding |
| Optogenetic PIP3 production | Real-time membrane dynamics | Live-cell imaging |
| Phagocytosis assay | PIP3-dependent bacterial uptake | Host defense studies |
| Vacuolar fusion assay | PIP3-dependent fusion | Trafficking studies |
| Epithelial polarity assay | Basolateral membrane formation | Polarity studies |
| Gelsolin co-precipitation | PIP3-dependent effector association | Cytoskeletal signaling |
| Lipid overlay | Domain-lipid specificity | Binding specificity testing |
Affinity proteomics for the PIP3 interactome
PIP3 interactome studies use lipid affinity matrices to capture proteins that bind PIP3, followed by mass spectrometry. This approach identified a broad set of PIP3 binders and revealed enrichment in nucleolar proteins when applied to nuclear fractions. Affinity proteomics is a discovery method that generates candidate genes for CRISPR validation.
Optogenetic and live-cell imaging
Optogenetic tools that produce PIP3 locally allow real-time imaging of PIP3 binding and membrane dynamics. These methods measure recruitment kinetics and membrane remodeling in living cells. They are useful for testing whether a specific PIP3-binding protein is required for a given membrane event.
Functional assays for phagocytosis and fusion
Phagocytosis assays with nonmotile Pseudomonas aeruginosa measure PIP3-dependent uptake and can be combined with CRISPR knockouts. Vacuolar fusion assays measure PIP3-dependent membrane microdomain assembly and fusion. These functional readouts connect PIP3 binding to physiological outcomes.
Polarity and membrane domain assays
Epithelial polarity assays assess basolateral membrane formation and can be used to test PIP3-binding proteins. Imaging of domain markers and ARF6/CDC42 localization provides readouts of PIP3-dependent membrane identity. These assays are suitable for knockout and rescue experiments.
How CRISPR Can Be Used to Study GO:0005547 phosphatidylinositol-3,4,5-trisphosphate binding
Knockout
CRISPR knockout of a candidate PIP3-binding gene removes the protein and allows testing of PIP3-dependent phenotypes such as phagocytosis, fusion or polarity. Knockout models are essential to determine whether the gene is required for PIP3 binding in cells.
Point Mutation
Point-mutation knock-in can disrupt the lipid-binding domain while preserving other protein functions, providing a clean test of PIP3 binding specificity. Such models help distinguish PIP3 binding from protein-protein interactions.
Knock-in
Tagged knock-in of endogenous PIP3-binding proteins enables localization and interaction studies under native regulation. Fluorescent or affinity tags allow imaging of PIP3-dependent recruitment in living cells.
Overexpression
Overexpression of wild-type or mutant PIP3-binding proteins can amplify or dominantly inhibit PIP3-dependent processes. This approach is useful for gain-of-function studies and for testing whether increased PIP3 binding drives membrane remodeling.
How EDITGENE Supports phosphatidylinositol-3,4,5-trisphosphate binding Research
Researchers studying phosphatidylinositol-3,4,5-trisphosphate binding-related genes often need to determine whether a candidate gene is causally involved in a phenotype, and CRISPR-based models provide the most direct way to test this. EDITGENE supports this workflow with knockout, point-mutation, knock-in, overexpression cell models and CRISPR library screening combined with bioinformatics.
Contact EDITGENE today to design your custom CRISPR model for phosphatidylinositol-3,4,5-trisphosphate binding research.
Frequently Asked Questions About phosphatidylinositol-3,4,5-trisphosphate binding
What is phosphatidylinositol-3,4,5-trisphosphate binding?
It is the molecular function GO:0005547, defined as binding to phosphatidylinositol-3,4,5-trisphosphate, a phosphatidylinositol derivative phosphorylated at the 3', 4' and 5' positions of the inositol ring.
What genes are involved in phosphatidylinositol-3,4,5-trisphosphate binding?
Genes encoding PIP3-binding proteins include VAM7, GSN, SRC, AKT1, PLEK, BTK, ARF6, RAC1, NPM1, NCL, VPS34, PTEN, PIK3CA, VAMP7, YPT7, PLD1 and CDC42.
What is the synonym for GO:0005547?
The synonym is PIP3 binding.
Which domains mediate PIP3 binding?
Pleckstrin homology (PH) domains and other lipid-binding modules mediate PIP3 binding.
How is PIP3 binding studied?
It is studied by affinity proteomics, optogenetic imaging, phagocytosis assays, vacuolar fusion assays and epithelial polarity assays.
Does PIP3 binding occur in the nucleus?
Yes, the nuclear PIP3 interactome is enriched in nucleolar proteins, indicating nuclear PIP3 binding.
What role does PIP3 binding play in phagocytosis?
PIP3 binding induces phagocytosis of nonmotile Pseudomonas aeruginosa.
How does PIP3 binding regulate membrane fusion?
Vacuolar PIP3 controls fusion through binding Vam7 and membrane microdomain assembly.
Can CRISPR be used to study PIP3 binding?
Yes, CRISPR knockout, point-mutation, knock-in and overexpression models can test the causal role of PIP3-binding proteins.
What diseases are linked to PIP3 binding?
PIP3 binding is linked to cancer signaling, infection and host defense, epithelial polarity disorders and membrane trafficking defects.
Conclusion
GO:0005547 phosphatidylinositol-3,4,5-trisphosphate binding defines a central molecular function that converts the lipid messenger PIP3 into signaling, trafficking, phagocytic and polarity outputs. The PIP3 interactome spans membrane and nucleolar compartments, and optogenetic and proteomic tools have made the function experimentally tractable. CRISPR-based knockout, point-mutation, knock-in and overexpression models provide the causal evidence needed to link PIP3-binding proteins to disease-relevant phenotypes.
References
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- 2. Mazloumi Gavgani F et al.. 2021. Nuclear Phosphatidylinositol 3,4,5-Trisphosphate Interactome Uncovers an Enrichment in Nucleolar Proteins.. Mol Cell Proteomics 20:100102 PMID: 34048982
- 3. Riehle RD et al.. 2013. Role of phosphatidylinositol 3,4,5-trisphosphate in cell signaling.. Adv Exp Med Biol 991:105-39 PMID: 23775693
- 4. Catimel B et al.. 2009. PI(3,4,5)P3 Interactome.. J Proteome Res 8(7):3712-26 PMID: 19463016
- 5. Demirdjian S et al.. 2018. Phosphatidylinositol-(3,4,5)-Trisphosphate Induces Phagocytosis of Nonmotile Pseudomonas aeruginosa.. Infect Immun 86(8) PMID: 29844235
- 6. Ueda Y et al.. 2019. Membrane Dynamics Induced by a Phosphatidylinositol 3,4,5-Trisphosphate Optogenetic Tool.. Anal Sci 35(1):57-63 PMID: 30393242
- 7. Chellaiah MA et al.. 2001. Phosphatidylinositol 3,4,5-trisphosphate directs association of Src homology 2-containing signaling proteins with gelsolin.. J Biol Chem 276(50):47434-44 PMID: 11577104
- 8. Gassama-Diagne A et al.. 2006. Phosphatidylinositol-3,4,5-trisphosphate regulates the formation of the basolateral plasma membrane in epithelial cells.. Nat Cell Biol 8(9):963-70 PMID: 16921364
