GO:1902635 1-phosphatidyl-1D-myo-inositol 4,5-bisphosphate biosynthetic process: Lipid Signaling Pathway, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:1902635 describes the biosynthetic process that produces 1-phosphatidyl-1D-myo-inositol 4,5-bisphosphate, also known as phosphatidylinositol-4,5-bisphosphate or PtdIns(4,5)P2.
• PtdIns(4,5)P2 is a membrane phospholipid that acts as a substrate for phospholipase C and phosphoinositide 3-kinase and as a direct regulator of ion channels and cytoskeletal proteins.
• The biosynthetic route involves sequential phosphorylation of phosphatidylinositol by phosphatidylinositol phosphate kinases, including PI4K and PIP5K family enzymes.
• PtdIns(4,5)P2 is enriched at the plasma membrane and its local synthesis controls calcium entry, vesicle trafficking, and actin dynamics.
• Dysregulation of PtdIns(4,5)P2 metabolism is linked to cancer, immune signaling, and neurological disorders through pathways such as PI3K/AKT and STING.
• CRISPR knockout, point-mutation, knock-in, and overexpression models enable causal dissection of genes in this biosynthetic process.
Description
1-phosphatidyl-1D-myo-inositol 4,5-bisphosphate biosynthetic process (GO:1902635) is the set of chemical reactions and pathways that generate phosphatidylinositol-4,5-bisphosphate, commonly abbreviated PtdIns(4,5)P2. This lipid is a minor but critically important component of eukaryotic membranes, where it serves as a precursor for second messengers and as a spatial cue for protein recruitment. The process is therefore central to signal transduction, membrane identity, and cytoskeletal organization. Researchers study GO:1902635 because PtdIns(4,5)P2 levels and turnover influence diverse cellular outputs, from calcium entry to immune activation. The phosphoinositide 3-kinase pathway, which consumes PtdIns(4,5)P2, is one of the most frequently mutated signaling axes in human cancer, underscoring the importance of understanding how this lipid is made. Moreover, direct modulation of ion channels by PtdIns(4,5)P2, such as KCNQ5, highlights its role beyond classical second-messenger generation. Consequently, the biosynthetic process is a focal point for cell biology, neurobiology, and oncology research.
1-phosphatidyl-1D-myo-inositol 4,5-bisphosphate biosynthetic process At A Glance
| GO ID | GO:1902635 |
|---|---|
| GO term | 1-phosphatidyl-1D-myo-inositol 4,5-bisphosphate biosynthetic process |
| Ontology | biological_process |
| Synonym | phosphatidylinositol-4,5-bisphosphate biosynthesis; PtdIns(4,5)P(2) biosynthesis; 1-phosphatidyl-1D-myo-inositol 4,5-bisphosphate synthesis |
| Major function | Production of the membrane phospholipid PtdIns(4,5)P2, a key signaling lipid and precursor for second messengers |
| Subcellular location | Primarily plasma membrane and associated membranes |
| Key enzymes | Phosphatidylinositol phosphate kinases (PIPKs), including PI4K and PIP5K family members |
| Related pathways | Phosphoinositide 3-kinase signaling, phospholipase C signaling, calcium entry |
| Disease relevance | Cancer, immune disorders, neurological conditions |
What Is GO:1902635?
In our own words, GO:1902635 encompasses the enzymatic steps that convert phosphatidylinositol and its phosphorylated derivatives into 1-phosphatidyl-1D-myo-inositol 4,5-bisphosphate. This includes the phosphorylation of phosphatidylinositol at the D-4 position and subsequently at the D-5 position of the inositol ring, reactions catalyzed by phosphatidylinositol phosphate kinases. The term covers the formation of the lipid product, not its subsequent metabolism or downstream signaling events. It is a biological process annotation used to describe the biosynthetic arm of PtdIns(4,5)P2 homeostasis.
Why Is 1-phosphatidyl-1D-myo-inositol 4,5-bisphosphate biosynthetic process Important in Cell Biology?
The biosynthetic process for PtdIns(4,5)P2 is important because this lipid sits at the intersection of many signaling pathways. It is the substrate for PI3K, generating PIP3 and activating AKT, a central oncogenic pathway. It is also the substrate for phospholipase C, producing IP3 and DAG, which control calcium release and protein kinase C activity. Beyond being a precursor, PtdIns(4,5)P2 directly binds and regulates ion channels, transporters, and actin-binding proteins, influencing membrane excitability and cytoskeletal dynamics. Recent work shows that phosphoinositides, including PtdIns(4,5)P2, regulate STING activation, linking this lipid to innate immunity. Thus, understanding GO:1902635 is fundamental to cell signaling, cancer biology, immunology, and neuroscience.
• Provides the substrate for PI3K, a major oncogenic signaling enzyme.
• Supplies phospholipase C with substrate to generate IP3 and DAG for calcium signaling.
• Directly activates or modulates ion channels such as KCNQ5.
• Regulates actin capping proteins and cytoskeletal organization.
• Controls membrane targeting of signaling proteins via lipid-binding domains.
• Influences innate immune signaling through STING regulation.
• Is essential for neurotransmission and synaptic function.
• Dysregulation is implicated in cancer, immune disorders, and neurodegeneration.
• Serves as a biomarker and therapeutic target in phosphoinositide-related diseases.
• Enables mechanistic studies using CRISPR screens and lipidomics.
What Happens During 1-phosphatidyl-1D-myo-inositol 4,5-bisphosphate biosynthetic process?
Substrate supply and phosphatidylinositol availability
In simple terms: The cell first needs the starting material, phosphatidylinositol, in the right membrane.
The biosynthetic process begins with phosphatidylinositol, which is synthesized in the endoplasmic reticulum and transferred to the plasma membrane and other organelles. Phosphatidic acid, a precursor for phosphatidylinositol, is also involved in neurotransmission and membrane lipid metabolism. The availability of phosphatidylinositol at specific membranes determines where PtdIns(4,5)P2 can be produced.
Phosphorylation at the D-4 position by PI4K
In simple terms: An enzyme adds a phosphate group to the inositol ring at position 4.
Phosphatidylinositol 4-kinases (PI4Ks) catalyze the phosphorylation of phosphatidylinositol to phosphatidylinositol 4-phosphate (PI4P). This step is a prerequisite for subsequent 5-phosphorylation. PI4K enzymes are localized to distinct membrane compartments, contributing to the spatial control of PtdIns(4,5)P2 synthesis.
Phosphorylation at the D-5 position by PIP5K
In simple terms: A second enzyme adds another phosphate at position 5 to make the final product.
Phosphatidylinositol 4-phosphate 5-kinases (PIP5Ks) phosphorylate PI4P at the D-5 position to generate PtdIns(4,5)P2. This reaction is the committed step in the biosynthetic process. PIP5K activity is regulated by small GTPases, lipid environment, and phosphorylation, allowing fine-tuned production of PtdIns(4,5)P2.
Membrane targeting and lipid domain organization
In simple terms: The product stays in the membrane and helps organize signaling platforms.
PtdIns(4,5)P2 remains in the membrane and is enriched in specific microdomains. Its headgroup is recognized by pleckstrin homology (PH) domains and other lipid-binding modules, which target proteins to the membrane. This spatial organization is critical for downstream signaling and for the regulation of ion channels and cytoskeletal elements.
Coupling to downstream signaling and calcium entry
In simple terms: Once made, this lipid can be cut or modified to send signals, including calcium signals.
PtdIns(4,5)P2 serves as a substrate for phospholipase C, producing IP3 and DAG, which trigger calcium release and activate protein kinase C. It is also the substrate for PI3K, generating PIP3 and activating AKT. Additionally, PtdIns(4,5)P2 directly controls calcium entry channels and other ion channels, as shown for KCNQ5. These downstream events link the biosynthetic process to diverse cellular responses.
Key Genes Involved in GO:1902635 1-phosphatidyl-1D-myo-inositol 4,5-bisphosphate biosynthetic process
The following genes and proteins are experimentally implicated in the biosynthesis, regulation, or downstream signaling of PtdIns(4,5)P2, based on published literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| PIK3CA | Phosphatidylinositol 3-kinase catalytic subunit alpha; consumes PtdIns(4,5)P2 to generate PIP3 | Oncogene frequently mutated in cancer; target for PI3K inhibitors |
| PIK3CB | PI3K catalytic subunit beta; lipid kinase in the PI3K pathway | Role in growth signaling and metabolism |
| PIK3CD | PI3K catalytic subunit delta; immune cell signaling | Target in hematological malignancies and immune disorders |
| PIK3CG | PI3K catalytic subunit gamma; GPCR-coupled signaling | Inflammation and immune cell migration |
| PIK3R1 | PI3K regulatory subunit alpha; modulates PI3K activity | Mutations in cancer and immune dysregulation |
| PI4KA | Phosphatidylinositol 4-kinase alpha; produces PI4P | Essential for PtdIns(4,5)P2 synthesis at plasma membrane |
| PI4KB | Phosphatidylinositol 4-kinase beta; produces PI4P | Role in Golgi and secretory pathway |
| PIP5K1A | Phosphatidylinositol-4-phosphate 5-kinase type 1 alpha; generates PtdIns(4,5)P2 | Regulates focal adhesion and actin dynamics |
| PIP5K1B | PIP5K type 1 beta; PtdIns(4,5)P2 synthesis | Implicated in synaptic function and hearing |
| PIP5K1C | PIP5K type 1 gamma; PtdIns(4,5)P2 synthesis | Role in cell migration and adhesion |
| PIP5K2A | Type 2 PIP5K; alternative route to PtdIns(4,5)P2 | Less characterized; potential context-dependent roles |
| PLCB1 | Phospholipase C beta 1; hydrolyzes PtdIns(4,5)P2 | Calcium signaling and neuronal function |
| PLCG1 | Phospholipase C gamma 1; hydrolyzes PtdIns(4,5)P2 | Growth factor signaling and cancer |
| KCNQ5 | Potassium channel activated by PtdIns(4,5)P2 | Neuronal excitability and M-current regulation |
| STING1 | Stimulator of interferon genes; regulated by phosphoinositides | Innate immunity and cancer immunotherapy |
| CAPZA1 | F-actin capping protein subunit alpha; regulated by phosphoinositides | Cytoskeletal dynamics |
| CAPZB | F-actin capping protein subunit beta; interacts with PtdIns(4,5)P2 | Actin assembly and cell motility |
How Is 1-phosphatidyl-1D-myo-inositol 4,5-bisphosphate biosynthetic process Regulated?
The biosynthetic process for PtdIns(4,5)P2 is regulated at multiple levels. PI4K and PIP5K enzymes are controlled by membrane recruitment, phosphorylation, and interaction with small GTPases. The lipid environment and availability of phosphatidylinositol also influence flux through the pathway. Downstream, PI3K and phospholipase C consume PtdIns(4,5)P2, creating a dynamic balance. Additionally, PtdIns(4,5)P2 levels are modulated by lipid phosphatases and by feedback from calcium signaling. Recent evidence indicates that phosphoinositides regulate STING, linking lipid metabolism to innate immune signaling. Thus, the process is integrated with growth factor signaling, calcium homeostasis, and immune responses.
1-phosphatidyl-1D-myo-inositol 4,5-bisphosphate biosynthetic process and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| PIK3CA | Cancer (breast, colorectal, endometrial) | Knock-in of activating mutations; organoid models |
| STING1 | Autoinflammatory and immune disorders | Knockout and point-mutation models to study lipid regulation |
| KCNQ5 | Epilepsy and neuronal excitability disorders | Knock-in of patient variants; electrophysiology |
| PLCB1 | Neurological disorders and calcium signaling defects | Knockout mice and neuronal cultures |
| PIP5K1C | Cell migration and adhesion defects | Conditional knockout and overexpression |
Cancer and the PI3K/AKT pathway
PtdIns(4,5)P2 is the substrate for PI3K, which is mutated or amplified in many cancers. Activating mutations in PIK3CA lead to increased PIP3 and constitutive AKT signaling, driving tumor growth. Therefore, the biosynthetic process that supplies PtdIns(4,5)P2 is indirectly critical for oncogenic signaling. Targeting enzymes in this pathway, such as PI4K and PIP5K, is an area of active investigation.
Immune signaling and STING
Phosphoinositides, including PtdIns(4,5)P2, regulate STING activation, a central node in innate immunity. Dysregulation of this lipid pathway can alter interferon responses and immune surveillance. This connection suggests that genes in GO:1902635 may influence autoimmune diseases and cancer immunotherapy outcomes.
Neurological and channelopathies
PtdIns(4,5)P2 directly activates KCNQ potassium channels, which control neuronal excitability. Mutations or imbalances in this lipid can affect channel function and contribute to neurological disorders such as epilepsy. Additionally, phospholipase C signaling downstream of PtdIns(4,5)P2 is essential for synaptic function and calcium signaling in neurons.
From 1-phosphatidyl-1D-myo-inositol 4,5-bisphosphate biosynthetic process-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of PI4KA reduce PtdIns(4,5)P2 levels? | CRISPR knockout in cell lines; lipidomics |
| Does a specific PIP5K1A point mutation alter enzyme activity? | Point-mutation knock-in via CRISPR |
| Can tagged PIP5K1B reveal its localization? | Knock-in of fluorescent or epitope tag |
| Does overexpression of PIP5K1C increase PtdIns(4,5)P2? | Overexpression cell model; live imaging |
| Which genes regulate PtdIns(4,5)P2 synthesis? | CRISPR library screening with lipid biosensors |
| Does PIK3CA mutation affect downstream AKT signaling? | Knock-in of oncogenic mutation; phospho-AKT assays |
How to Study the 1-phosphatidyl-1D-myo-inositol 4,5-bisphosphate biosynthetic process Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Lipidomics (LC-MS) | Levels of PtdIns(4,5)P2 and other lipids | Quantify changes after gene knockout |
| Fluorescent lipid biosensors | Spatiotemporal distribution of PtdIns(4,5)P2 | Live-cell imaging of membrane domains |
| CRISPR knockout screens | Genes affecting lipid levels or signaling | Discovery of novel regulators |
| Phospho-AKT immunoblotting | PI3K pathway activity | Assess downstream effects of PtdIns(4,5)P2 changes |
| Patch-clamp electrophysiology | Ion channel activity modulated by PtdIns(4,5)P2 | Study KCNQ5 or other channels |
| Calcium imaging | Intracellular calcium release | Measure PLC-mediated signaling |
| Co-immunoprecipitation | Protein-protein interactions with PIPKs | Identify regulatory complexes |
| RNA-seq | Transcriptional changes after perturbation | Global effects of lipid pathway modulation |
Lipidomics and mass spectrometry
Mass spectrometry-based lipidomics can quantify PtdIns(4,5)P2 and related phosphoinositides in cells and tissues. This method is essential to measure changes in the biosynthetic process after genetic perturbation.
Live-cell imaging with lipid biosensors
Genetically encoded biosensors, such as PH domains fused to fluorescent proteins, allow real-time visualization of PtdIns(4,5)P2 distribution and dynamics. These tools reveal spatial regulation at the plasma membrane and other organelles.
CRISPR screening and functional genomics
Genome-wide CRISPR knockout or activation screens can identify genes that regulate PtdIns(4,5)P2 levels or downstream signaling. Such screens are powerful for discovering novel regulators of GO:1902635.
Electrophysiology and calcium imaging
Because PtdIns(4,5)P2 modulates ion channels and calcium entry, patch-clamp electrophysiology and calcium imaging are used to assess functional consequences of altered lipid synthesis.
How CRISPR Can Be Used to Study GO:1902635 1-phosphatidyl-1D-myo-inositol 4,5-bisphosphate biosynthetic process
Knockout
CRISPR knockout of genes such as PI4KA, PIP5K1A, or PIK3CA can abolish or reduce PtdIns(4,5)P2 synthesis, revealing their necessity in the biosynthetic process. Knockout cell models are used to measure lipid levels, downstream signaling, and phenotypic changes.
Point Mutation
Point mutations can be introduced to mimic disease-associated variants or to disable catalytic activity. For example, kinase-dead mutants of PIP5K1A can test whether enzymatic activity is required for PtdIns(4,5)P2 production. Such models help dissect specific residues involved in substrate binding or regulation.
Knock-in
Knock-in of tagged versions of PI4K or PIP5K enzymes allows visualization and purification of these proteins in their native context. This approach is valuable for studying localization and interaction partners without overexpression artifacts.
Overexpression
Overexpression of PIP5K or PI4K genes can increase PtdIns(4,5)P2 levels, enabling gain-of-function studies. This is useful to test sufficiency of a single enzyme in driving the biosynthetic process and downstream phenotypes.
How EDITGENE Supports 1-phosphatidyl-1D-myo-inositol 4,5-bisphosphate biosynthetic process Research
Researchers studying 1-phosphatidyl-1D-myo-inositol 4,5-bisphosphate biosynthetic process-related genes often need to determine whether a candidate gene is causally involved in lipid synthesis, signaling, or disease. EDITGENE provides tailored CRISPR cell models and screening services to accelerate this discovery.
Contact EDITGENE today to design your custom CRISPR model for 1-phosphatidyl-1D-myo-inositol 4,5-bisphosphate biosynthetic process research.
Frequently Asked Questions About 1-phosphatidyl-1D-myo-inositol 4,5-bisphosphate biosynthetic process
What is GO:1902635?
GO:1902635 is the Gene Ontology term for the biosynthetic process that produces 1-phosphatidyl-1D-myo-inositol 4,5-bisphosphate, also known as PtdIns(4,5)P2.
What genes are involved in 1-phosphatidyl-1D-myo-inositol 4,5-bisphosphate biosynthetic process?
Key genes include PI4KA, PI4KB, PIP5K1A, PIP5K1B, PIP5K1C, and PIP5K2A, which encode kinases that synthesize PtdIns(4,5)P2.
What is the function of PtdIns(4,5)P2?
PtdIns(4,5)P2 is a membrane phospholipid that serves as a substrate for PI3K and phospholipase C and directly regulates ion channels and actin-binding proteins.
How is PtdIns(4,5)P2 synthesized?
It is synthesized by sequential phosphorylation of phosphatidylinositol by PI4K and PIP5K enzymes.
Which diseases are linked to PtdIns(4,5)P2 biosynthesis?
Dysregulation is linked to cancer, immune disorders, and neurological conditions through PI3K/AKT, STING, and ion channel pathways.
What methods are used to study this process?
Common methods include lipidomics, live-cell imaging with lipid biosensors, CRISPR screens, and electrophysiology.
How does PtdIns(4,5)P2 regulate ion channels?
It directly binds and activates channels such as KCNQ5, influencing neuronal excitability.
What is the role of PI3K in this pathway?
PI3K consumes PtdIns(4,5)P2 to generate PIP3, activating AKT signaling, which is frequently altered in cancer.
Can CRISPR be used to study PtdIns(4,5)P2 synthesis?
Yes, CRISPR knockout, point mutation, knock-in, and overexpression models are widely used to dissect gene function in this pathway.
What is the relationship between PtdIns(4,5)P2 and STING?
Phosphoinositides including PtdIns(4,5)P2 regulate STING activation, linking lipid metabolism to innate immunity.
Conclusion
GO:1902635 defines the biosynthetic process for PtdIns(4,5)P2, a lipid at the heart of many signaling pathways. Its regulation impacts cancer, immunity, and neuronal function, making it a rich area for mechanistic and translational research. By combining CRISPR models with lipidomics and functional assays, researchers can uncover how this process contributes to health and disease.
References
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- 2. Li J et al.. 2026. Regulation of STING activation by phosphoinositide and cholesterol.. Nature 652(8109):499-507 PMID: 41639452
- 3. Taylor CW. 2002. Controlling calcium entry.. Cell 111(6):767-9 PMID: 12526803
- 4. Giudici ML et al.. 2004. Phosphatidylinositol phosphate kinases.. J Endocrinol Invest 27(6 Suppl):137-42 PMID: 15481814
- 5. Raben DM et al.. 2017. Phosphatidic acid and neurotransmission.. Adv Biol Regul 63:15-21 PMID: 27671966
- 6. Weeds A et al.. 1993. F-actin capping proteins.. Curr Opin Cell Biol 5(1):63-9 PMID: 8383512
- 7. Hurley JH et al.. 2001. Subcellular targeting by membrane lipids.. Curr Opin Cell Biol 13(2):146-52 PMID: 11248547
- 8. Yang Z et al.. 2025. Phosphatidylinositol 4,5-bisphosphate activation mechanism of human KCNQ5.. Proc Natl Acad Sci U S A 122(14):e2416738122 PMID: 40172963
