GO:0016308 1-phosphatidylinositol-4-phosphate 5-kinase activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0016308 defines the enzymatic activity that converts phosphatidylinositol 4-phosphate (PI4P) to phosphatidylinositol 4,5-bisphosphate (PIP2) by transferring a phosphate from ATP.
• This activity is carried out by type I phosphatidylinositol 4-phosphate 5-kinases (PIP5Ks), which are conserved regulators of membrane identity, actin dynamics, and cell signaling.
• PIP5K activity is essential for diverse cellular processes including vesicular trafficking, cell proliferation, and survival, and its dysregulation is linked to cancer and other diseases.
• The catalytic mechanism involves substrate binding, ATP-dependent phosphorylation, and release of ADP and H+, and can be measured using fluorescence spectroscopy or thin-layer chromatography.
• PIP5K enzymes are regulated by partner proteins, dimerization, and post-translational modifications, which determine their membrane localization and activity.
• CRISPR-based models (knockout, point mutation, knock-in, overexpression) are powerful tools to dissect the causal roles of PIP5K genes in health and disease.
Description
1-phosphatidylinositol-4-phosphate 5-kinase activity (GO:0016308) is a molecular function that catalyzes the phosphorylation of phosphatidylinositol 4-phosphate (PI4P) to generate phosphatidylinositol 4,5-bisphosphate (PIP2), a critical lipid second messenger. This reaction is performed by type I phosphatidylinositol 4-phosphate 5-kinases (PIP5Ks), which are evolutionarily conserved enzymes that play central roles in membrane trafficking, cytoskeletal organization, and signal transduction. The activity was first described decades ago and has since been implicated in a wide range of physiological and pathological processes, including cell proliferation, survival, and malignancy. Understanding GO:0016308 is therefore essential for researchers studying lipid signaling, membrane dynamics, and cancer biology. The enzymatic reaction consumes ATP and produces PIP2, which serves as a precursor for other signaling lipids and as a docking site for numerous effector proteins. Dysregulation of PIP5K activity has been observed in various cancers and other diseases, making it an attractive target for therapeutic intervention. This article provides a comprehensive overview of the definition, mechanism, key genes, research methods, and disease relevance of GO:0016308, with a focus on how CRISPR-based models can accelerate discovery.
1-phosphatidylinositol-4-phosphate 5-kinase activity At A Glance
| GO ID | GO:0016308 |
|---|---|
| GO term | 1-phosphatidylinositol-4-phosphate 5-kinase activity |
| Ontology | molecular_function |
| Synonym | PIP5K, PIP kinase activity, phosphatidylinositol-4-phosphate 5-kinase activity, type I PIP kinase activity |
| Major function | Catalyzes the phosphorylation of PI4P to PIP2, a key lipid second messenger |
| Reaction | 1-phosphatidyl-1D-myo-inositol 4-phosphate + ATP = 1-phosphatidyl-1D-myo-inositol 4,5-bisphosphate + ADP + H+ |
| EC number | 2.7.1.68 |
| Subcellular location | Plasma membrane, endosomes, and other membranous compartments |
| Related genes | PIP5K1A, PIP5K1B, PIP5K1C, and others |
What Is GO:0016308?
GO:0016308, 1-phosphatidylinositol-4-phosphate 5-kinase activity, is defined as the catalysis of the reaction: a 1-phosphatidyl-1D-myo-inositol 4-phosphate + ATP = a 1-phosphatidyl-1D-myo-inositol 4,5-bisphosphate + ADP + H+. In simpler terms, it is the enzyme activity that adds a phosphate group to PI4P to produce PIP2, using ATP as the phosphate donor.
Why Is 1-phosphatidylinositol-4-phosphate 5-kinase activity Important in Cell Biology?
GO:0016308 is fundamentally important because the product of the reaction, PIP2, is a pivotal signaling lipid that regulates a multitude of cellular processes, including ion channel activity, actin cytoskeleton remodeling, endocytosis, exocytosis, and cell survival. PIP5K enzymes are often overexpressed in cancer and contribute to tumorigenesis, making them potential therapeutic targets. Moreover, PIP2 is a substrate for phospholipase C and phosphoinositide 3-kinase, linking this activity to calcium signaling and Akt pathways. Thus, understanding the regulation and function of GO:0016308 is critical for both basic cell biology and translational research.
• PIP5K activity generates PIP2, a lipid that recruits and activates many signaling proteins.
• It is essential for membrane trafficking and cytoskeletal dynamics.
• Dysregulation of PIP5K is linked to cancer progression and metastasis.
• PIP5K enzymes are regulated by partner proteins and dimerization, affecting their localization and activity.
• The activity can be measured using fluorescence-based assays or thin-layer chromatography.
• PIP5K is a potential target for anticancer therapy.
• It plays a role in ferroptosis suppression and drug resistance in hepatocellular carcinoma.
• Conserved biochemical activity of PIP5K regulates growth and development in model organisms.
• PIP5K activity is linked to proliferation and malignancy in signal transduction.
• Understanding PIP5K function can inform CRISPR-based disease modeling.
Molecular Mechanism of 1-phosphatidylinositol-4-phosphate 5-kinase activity
Substrate Binding and Catalysis
In simple terms: The enzyme grabs PI4P and ATP, then transfers a phosphate from ATP to PI4P.
The catalytic mechanism of GO:0016308 involves the binding of the substrate 1-phosphatidyl-1D-myo-inositol 4-phosphate (PI4P) and ATP to the active site of the enzyme. The enzyme then catalyzes the transfer of the gamma-phosphate of ATP to the D-5 position of the inositol ring, producing 1-phosphatidyl-1D-myo-inositol 4,5-bisphosphate (PIP2), ADP, and a proton. This reaction is highly conserved and is essential for the generation of PIP2, which serves as a precursor for other signaling molecules and as a membrane anchor for various proteins.
Enzyme Structure and Dimerization
In simple terms: PIP5K enzymes can pair up (dimerize), which helps them attach to membranes and work properly.
Type I PIP5Ks are multidomain proteins that can form homo- and heterodimers. Dimerization is critical for their membrane localization and enzymatic activity. The dimerization interface and the membrane-binding domains (such as the PIP5K domain and the dimerization domain) determine how the enzyme interacts with lipid bilayers and partner proteins. Structural studies have revealed that dimerization can regulate substrate access and catalytic efficiency.
Regulation by Partner Proteins
In simple terms: Other proteins can stick to PIP5K and turn its activity up or down.
PIP5K activity is regulated by a variety of partner proteins that bind to the enzyme and modulate its localization, substrate affinity, or catalytic rate. For example, small GTPases such as Rho and Rac can activate PIP5K, while other proteins may inhibit it. These interactions allow cells to spatially and temporally control PIP2 production in response to extracellular signals.
Cofactors and Cations
In simple terms: The enzyme needs magnesium ions to work.
Like many kinases, PIP5K requires divalent cations, typically Mg2+, for ATP binding and catalysis. The reaction is also sensitive to pH and ionic strength, which can affect enzyme activity. These cofactors are essential for the phosphotransfer reaction and are often included in in vitro assays.
Assays for Measuring Activity
In simple terms: Scientists can measure how fast PIP5K makes PIP2 using special tests.
Several methods exist to measure GO:0016308 activity. A real-time fluorescence spectroscopy assay allows continuous monitoring of PIP2 production. Alternatively, thin-layer chromatography can separate and quantify radiolabeled lipids after the reaction. These assays are crucial for studying enzyme kinetics, regulation, and inhibitor screening.
Key Genes Involved in GO:0016308 1-phosphatidylinositol-4-phosphate 5-kinase activity
The following genes encode proteins that exhibit 1-phosphatidylinositol-4-phosphate 5-kinase activity or are directly involved in its regulation.
| Gene | Major Role | Research Relevance |
|---|---|---|
| PIP5K1A | Type I PIP5K alpha; synthesizes PIP2 | Implicated in cancer, ferroptosis suppression, and drug resistance |
| PIP5K1B | Type I PIP5K beta; synthesizes PIP2 | Role in membrane trafficking and signaling |
| PIP5K1C | Type I PIP5K gamma; synthesizes PIP2 | Regulates focal adhesions and cell migration |
| PIP5K2A | Type II PIP5K alpha; phosphorylates PI5P | May have distinct functions from type I |
| PIP5K2B | Type II PIP5K beta; phosphorylates PI5P | Less studied, potential role in signaling |
| PIP5K2C | Type II PIP5K gamma; phosphorylates PI5P | Enigmatic lipid signaling |
| PI4KA | Produces PI4P, the substrate for PIP5K | Upstream regulator of PIP2 synthesis |
| PI4KB | Produces PI4P | Upstream regulator |
| RhoA | Activates PIP5K | Regulates cytoskeletal dynamics |
| Rac1 | Activates PIP5K | Regulates membrane ruffling |
| Arf6 | Recruits PIP5K to membranes | Regulates endocytosis |
| PLCδ1 | Consumes PIP2 | Downstream effector |
| PI3K | Converts PIP2 to PIP3 | Downstream signaling |
| PTEN | Dephosphorylates PIP3 to PIP2 | Tumor suppressor |
| NRF2 | Stabilized by PIP5K1A | Ferroptosis resistance |
| AP-2 | Binds PIP2 for endocytosis | Trafficking |
| Actin | Regulated by PIP2 | Cytoskeleton |
How Is 1-phosphatidylinositol-4-phosphate 5-kinase activity Regulated?
PIP5K activity is regulated at multiple levels. Partner proteins such as Rho GTPases and Arf6 can recruit PIP5K to specific membranes and activate it. Dimerization of PIP5K enzymes also modulates their activity and localization. Additionally, phosphorylation and other post-translational modifications may affect enzyme function. The activity is also influenced by the availability of substrate PI4P, which is produced by PI4K enzymes. In cancer, PIP5K1A expression can be upregulated, leading to increased PIP2 and activation of survival pathways.
1-phosphatidylinositol-4-phosphate 5-kinase activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| PIP5K1A | Hepatocellular carcinoma, ferroptosis resistance | Knockout or overexpression in HCC cell lines |
| PIP5K1C | Cell migration, focal adhesion dynamics | Point mutation or knockout in fibroblasts |
| PIP5K1B | Membrane trafficking | Knockout in epithelial cells |
| PIP5K2A | Lipid signaling | Overexpression in cell lines |
| PIP5K2B | Unknown | Knockout models |
Cancer
PIP5K1A is overexpressed in hepatocellular carcinoma and promotes ferroptosis resistance and sorafenib resistance by stabilizing NRF2. The enzyme's product PIP2 contributes to oncogenic signaling, and its activity is linked to proliferation and malignancy. Targeting PIP5K may therefore be a therapeutic strategy in cancers with high PIP5K activity.
Neurodegeneration
While direct links are less established, PIP2 is critical for synaptic vesicle trafficking and ion channel function, and altered PIP5K activity could contribute to neurodegenerative processes. Further research is needed to clarify these connections.
Metabolic Disorders
PIP5K activity influences insulin signaling and glucose transport through PIP2-dependent pathways. Dysregulation may contribute to insulin resistance, though specific evidence is still emerging.
From 1-phosphatidylinositol-4-phosphate 5-kinase activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does PIP5K1A loss affect ferroptosis? | PIP5K1A knockout in HCC cells |
| How does PIP5K1C dimerization affect localization? | Point mutations in dimerization domain |
| Can PIP5K1A overexpression induce sorafenib resistance? | Overexpression in sensitive cell lines |
| What is the role of PIP5K1B in trafficking? | Knockout in HeLa cells |
| Does PIP5K activity regulate actin dynamics? | Knock-in of tagged PIP5K |
| Is PIP5K2A involved in PIP2 synthesis? | Overexpression and knockdown |
How to Study the 1-phosphatidylinositol-4-phosphate 5-kinase activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Fluorescence spectroscopy | Real-time PIP2 production | Kinase activity assays |
| Thin-layer chromatography | Radiolabeled PIP2 | Enzyme kinetics |
| CRISPR knockout | Gene function loss | Disease models |
| CRISPR knock-in | Tagged protein expression | Localization studies |
| Lipidomics | PIP2 levels | Metabolic profiling |
| Proteomics | Protein interactions | Partner identification |
| RNA-seq | Transcriptional changes | Pathway analysis |
Fluorescence-Based Kinase Assay
A real-time fluorescence spectroscopy assay can measure PIP5K activity continuously by monitoring the production of PIP2. This method is sensitive and suitable for high-throughput screening.
Thin-Layer Chromatography
Thin-layer chromatography (TLC) can separate radiolabeled lipids after the PIP5K reaction, allowing quantification of PIP2. This classic method is reliable but less high-throughput.
CRISPR-Based Genetic Models
CRISPR/Cas9 can generate knockout, point mutation, knock-in, or overexpression models to study PIP5K genes in cells and animals. These models help establish causal roles in disease.
Lipidomics and Proteomics
Mass spectrometry-based lipidomics can quantify PIP2 levels, while proteomics can identify proteins interacting with PIP5K. These approaches provide systems-level insights.
How CRISPR Can Be Used to Study GO:0016308 1-phosphatidylinositol-4-phosphate 5-kinase activity
Knockout
CRISPR knockout of PIP5K genes can abolish enzyme activity, revealing its role in cellular processes such as ferroptosis and proliferation. Knockout models are essential for loss-of-function studies.
Point Mutation
Point mutations can be introduced to disrupt catalytic residues or regulatory sites, allowing precise dissection of PIP5K function without completely removing the protein.
Knock-in
Knock-in of tagged PIP5K (e.g., GFP) enables live-cell imaging and proteomic analysis of localization and interactions.
Overexpression
Overexpression of PIP5K1A can mimic the upregulation seen in cancers and induce phenotypes such as drug resistance. This is useful for gain-of-function studies.
How EDITGENE Supports 1-phosphatidylinositol-4-phosphate 5-kinase activity Research
Researchers studying 1-phosphatidylinositol-4-phosphate 5-kinase activity-related genes often need to determine whether a candidate gene is causally involved in a specific cellular process or disease. EDITGENE provides comprehensive CRISPR-based services to generate precisely engineered cell models, enabling rigorous functional studies.
Contact EDITGENE today to design your custom CRISPR model for 1-phosphatidylinositol-4-phosphate 5-kinase activity research.
Frequently Asked Questions About 1-phosphatidylinositol-4-phosphate 5-kinase activity
What is 1-phosphatidylinositol-4-phosphate 5-kinase activity?
It is the enzymatic activity (GO:0016308) that converts PI4P to PIP2 by adding a phosphate from ATP.
What genes encode 1-phosphatidylinositol-4-phosphate 5-kinase?
The main genes are PIP5K1A, PIP5K1B, PIP5K1C, and type II PIP5K2A/B/C.
How is PIP5K activity measured?
It can be measured using fluorescence spectroscopy or thin-layer chromatography.
What diseases are associated with PIP5K?
PIP5K1A is linked to hepatocellular carcinoma and drug resistance; PIP5K activity is also linked to malignancy.
What is the role of PIP2?
PIP2 is a lipid second messenger that regulates ion channels, actin dynamics, and membrane trafficking.
How is PIP5K regulated?
It is regulated by partner proteins, dimerization, and post-translational modifications.
Can CRISPR be used to study PIP5K?
Yes, CRISPR knockout, point mutation, knock-in, and overexpression models are powerful tools.
What is the reaction catalyzed by GO:0016308?
PI4P + ATP = PIP2 + ADP + H+.
Is PIP5K a therapeutic target?
Yes, especially in cancers with high PIP5K activity.
What model organisms are used to study PIP5K?
Cell lines, mice, and other model organisms are used; conserved function has been shown.
Conclusion
1-phosphatidylinositol-4-phosphate 5-kinase activity (GO:0016308) is a fundamental enzymatic function that generates the critical lipid second messenger PIP2. Its regulation and dysregulation impact numerous cellular processes and diseases, particularly cancer. Continued research using advanced CRISPR models and biochemical assays will further illuminate its roles and therapeutic potential.
References
- 1. Giudici ML et al.. 2016. Phosphatidylinositol 5-phosphate 4-kinase γ (PI5P4Kγ), a lipid signalling enigma.. Adv Biol Regul 61:47-50 PMID: 26710750
- 2. Nishimura T. 2021. A Real-Time Phosphatidylinositol 4-Phosphate 5-Kinase Assay Using Fluorescence Spectroscopy.. Methods Mol Biol 2251:121-132 PMID: 33481235
- 3. Guo M et al.. 2025. PIP5K1A Suppresses Ferroptosis and Induces Sorafenib Resistance by Stabilizing NRF2 in Hepatocellular Carcinoma.. Adv Sci (Weinh) 12(30):e04372 PMID: 40405713
- 4. Parker GJ et al.. 1998. Detection of phosphatidylinositol-4-phosphate 5-kinase activity using thin-layer chromatography.. Methods Mol Biol 105:127-39 PMID: 10427556
- 5. Krishnan H et al.. 2025. Conserved biochemical activity and function of phosphatidylinositol 5-phosphate 4-kinase regulates growth and development.. J Cell Sci 138(13) PMID: 40539330
- 6. Kanaho Y et al.. 2007. Regulation of phosphatidylinositol 4-phosphate 5-kinase activity by partner proteins.. Methods Enzymol 434:155-69 PMID: 17954247
- 7. Lacalle RA et al.. 2015. Type I phosphatidylinositol 4-phosphate 5-kinase homo- and heterodimerization determines its membrane localization and activity.. FASEB J 29(6):2371-85 PMID: 25713054
- 8. Singhal RL et al.. 1994. 1-Phosphatidylinositol 4-phosphate 5-kinase (EC 2.7.1.68): a proliferation- and malignancy-linked signal transduction enzyme.. Cancer Res 54(21):5574-8 PMID: 7923199
