GO:0070300 phosphatidic acid binding: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0070300 (phosphatidic acid binding) is a molecular function describing the selective, non-covalent binding of proteins to phosphatidic acid (PA), a glycerol phosphate with both remaining glycerol hydroxyls esterified to fatty acids.
• PA-binding proteins are defined by positively charged and hydrophobic motifs that recognize the small, cone-shaped PA headgroup, and this binding often depends on the local lipid environment and membrane curvature.
• PA binding regulates diverse cellular processes including mTOR signaling, autophagy, mitochondrial dynamics, nuclear membrane homeostasis, and bacterial effector targeting.
• Key PA-binding proteins include diacylglycerol kinases, phospholipase D, mTOR, RMDN3/PTPIP51, seipin, and glycolytic enzymes such as GAPC and PGK.
• Dysregulated PA binding is implicated in cancer, metabolic disorders, neurodegeneration, and infectious disease, making it a target for therapeutic and diagnostic research.
• CRISPR knockout, point-mutation, knock-in, and overexpression models are essential to dissect the causal roles of PA-binding motifs in health and disease.
Description
Phosphatidic acid (PA) is the simplest glycerophospholipid, consisting of a glycerol backbone with two fatty acyl chains and a single phosphate group. Beyond its role as a biosynthetic intermediate, PA acts as a signaling lipid that recruits specific proteins to membranes through a molecular function defined as phosphatidic acid binding (GO:0070300). This binding event is critical for spatiotemporal control of enzyme activity, membrane trafficking, and signal transduction. Researchers study PA binding to understand how cells decode lipid signals into physiological outputs, and how misregulation contributes to diseases such as cancer and neurodegeneration. The identification of PA-binding proteins has accelerated with lipid overlay assays, mass spectrometry, and genetic screens, revealing a growing list of effectors that share PA-binding domains or motifs. In this article, we synthesize authoritative QuickGO data and verified PubMed literature to provide a research-grade overview of GO:0070300, its mechanisms, key genes, disease links, and experimental strategies.
phosphatidic acid binding At A Glance
| GO ID | GO:0070300 |
|---|---|
| GO term | phosphatidic acid binding |
| Ontology | molecular_function |
| Synonym | phosphatidate binding |
| Definition | Binding to phosphatidic acid, any of a class of glycerol phosphate in which both the remaining hydroxyl groups of the glycerol moiety are esterified with fatty acids. |
| Major function | Recruitment and regulation of proteins at membranes in signaling, trafficking, and metabolism |
| Representative proteins | DGK, PLD, mTOR, RMDN3/PTPIP51, seipin, GAPC, PGK |
| Disease relevance | Cancer, metabolic disorders, neurodegeneration, infectious disease |
What Is GO:0070300?
GO:0070300 (phosphatidic acid binding) is defined by QuickGO as the binding to phosphatidic acid, any of a class of glycerol phosphate in which both the remaining hydroxyl groups of the glycerol moiety are esterified with fatty acids. In practice, this molecular function describes the selective, non-covalent interaction between a protein and PA, often mediated by electrostatic and hydrophobic contacts that distinguish PA from other anionic phospholipids.
Why Is phosphatidic acid binding Important in Cell Biology?
Phosphatidic acid binding is a central mechanism by which cells convert lipid signals into specific biological outcomes, influencing processes as diverse as mTOR activation, autophagy suppression, mitochondrial dynamics, and nuclear membrane lipid homeostasis. Because PA is a minor but highly dynamic lipid, its binding partners act as sensitive detectors of lipid flux, and their dysfunction is linked to major human diseases including cancer and neurodegeneration. Understanding GO:0070300 therefore provides mechanistic insight into lipid signaling and identifies candidate targets for therapeutic intervention.
• PA binding regulates mTOR signaling, a master controller of cell growth and metabolism.
• PA binding by GAPC and PGK suppresses autophagy through competitive inhibition, linking lipid signaling to nutrient stress responses.
• RMDN3/PTPIP51 PA-binding activity is regulated by MITOL, affecting mitochondrial-associated membrane dynamics.
• Seipin governs PA homeostasis at the inner nuclear membrane, with implications for nuclear envelope integrity.
• Bacterial effector Lpg1137 requires PA binding to target syntaxin 17, highlighting a role in host-pathogen interactions.
• PA-binding proteins are implicated in cancer progression through altered phospholipase D and diacylglycerol kinase signaling.
• Neurodegenerative conditions may involve disrupted PA binding in mitochondrial and autophagic pathways.
• PA binding is a druggable interface, with small molecules and peptides being explored to modulate lipid-protein interactions.
• Methodological advances in lipidomics and proteomics enable systematic discovery of PA-binding proteins.
• CRISPR-based models allow precise dissection of PA-binding motifs in endogenous genes.
What Happens During phosphatidic acid binding?
Membrane recruitment and recognition
In simple terms: Proteins find and attach to PA on the membrane surface.
PA-binding proteins are recruited from the cytosol or from other membranes to PA-enriched regions through electrostatic interactions between positively charged residues and the PA phosphate, complemented by hydrophobic insertion into the lipid bilayer. This recruitment is often facilitated by membrane curvature and local lipid composition, as PA is a cone-shaped lipid that favors negative curvature. For example, phospholipase D and diacylglycerol kinase generate PA that then recruits their own binding partners in a feedback manner.
Conformational change and activation
In simple terms: Binding to PA can flip a protein into its active shape.
Upon PA binding, many proteins undergo conformational changes that relieve autoinhibition or promote oligomerization, thereby activating enzymatic or scaffolding functions. mTOR, for instance, is activated by PA binding through its FRB domain, which stabilizes the kinase complex at the lysosomal membrane. Similarly, RMDN3/PTPIP51 requires PA binding for its mitochondrial distribution and function, and this interaction is modulated by MITOL-mediated ubiquitination.
Signal integration and downstream effects
In simple terms: PA binding sends a signal that changes what the cell does.
PA binding serves as a signal integration node, translating changes in lipid metabolism into downstream cellular responses such as autophagy, membrane trafficking, and organelle dynamics. For example, PA binding to GAPC and PGK competitively inhibits their glycolytic functions, thereby suppressing autophagy under nutrient-rich conditions. In the nucleus, seipin binds PA to maintain inner nuclear membrane lipid homeostasis, affecting nuclear envelope morphology.
Termination and reversibility
In simple terms: The interaction can be turned off when PA levels drop or proteins are modified.
PA binding is reversible and is terminated by PA hydrolysis, conversion to diacylglycerol or cytidine diphosphate-diacylglycerol, or by post-translational modifications of the binding protein. MITOL-mediated ubiquitination of RMDN3/PTPIP51 reduces its PA-binding activity, illustrating how cells dynamically control this interaction. Such reversibility allows rapid adaptation to metabolic and signaling cues.
Key Genes Involved in GO:0070300 phosphatidic acid binding
The following genes and proteins represent major PA-binding effectors and regulators, supported by verified literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| DGK | Diacylglycerol kinase; generates PA and binds PA | Enzyme family with PA-binding domains; studied in cancer and signaling |
| PLD | Phospholipase D; produces PA and interacts with PA-binding partners | Central to PA-mediated signaling and membrane trafficking |
| MTOR | Serine/threonine kinase; binds PA for activation | Master regulator of growth; PA binding is critical for mTORC1 signaling |
| RMDN3/PTPIP51 | Mitochondrial protein; binds PA to regulate dynamics | PA-binding activity regulated by MITOL; linked to mitochondrial function |
| SEIPIN | Nuclear membrane protein; binds PA | Governs PA homeostasis at inner nuclear membrane |
| GAPC | Glyceraldehyde-3-phosphate dehydrogenase; binds PA | Competitive inhibition by PA suppresses autophagy |
| PGK | Phosphoglycerate kinase; binds PA | PA binding inhibits glycolytic function and autophagy |
| Lpg1137 | Bacterial effector protein; binds PA | Targets syntaxin 17 in host cells; requires PA binding |
| SPTBN1 | Spectrin beta; potential PA-binding protein | Identified in PA-binding proteomes |
| RAF1 | Raf-1 kinase; PA-binding protein | PA binding contributes to MAPK signaling |
| PIP5K | Phosphatidylinositol-4-phosphate 5-kinase; PA-binding | PA regulates PIP5K activity and actin dynamics |
| PKC | Protein kinase C; PA-binding | PA modulates PKC activity and localization |
| ARF | ADP-ribosylation factor; PA-binding | PA binding affects vesicle trafficking |
| K-Ras | Small GTPase; PA-binding | PA binding influences Ras signaling and membrane targeting |
| mTORC2 | Kinase complex; PA-binding | PA regulates mTORC2 activity |
| S6K | Ribosomal protein S6 kinase; PA-binding | Downstream of mTOR; PA binding may affect activation |
| 4E-BP1 | Translation repressor; PA-binding | PA binding may modulate mTORC1 output |
| Syntaxin 17 | SNARE protein; targeted by Lpg1137 | PA binding of Lpg1137 required for syntaxin 17 distribution |
How Is phosphatidic acid binding Regulated?
Phosphatidic acid binding is regulated at multiple levels. The availability of PA itself is controlled by enzymes such as phospholipase D and diacylglycerol kinase, which produce PA, and by lipid phosphatases that consume it. Post-translational modifications of the binding protein, such as MITOL-mediated ubiquitination of RMDN3/PTPIP51, can directly modulate PA-binding affinity. Additionally, mTOR signaling is both a target and a regulator of PA binding, forming feedback loops that integrate nutrient status. In the nucleus, seipin maintains PA homeostasis, and its loss alters PA-binding protein distribution. These regulatory layers ensure that PA binding is dynamic and context-dependent.
phosphatidic acid binding and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| MTOR | Cancer, metabolic disorders | Knockout of PA-binding domain; point mutations in FRB domain |
| RMDN3/PTPIP51 | Neurodegeneration, mitochondrial dysfunction | Point mutation of PA-binding residues; knockout |
| SEIPIN | Lipodystrophy, nuclear envelope defects | Knock-in of patient mutations; knockout |
| GAPC/PGK | Metabolic disorders, autophagy dysregulation | Overexpression of PA-binding mutants; knockout |
| Lpg1137 | Legionella infection | Bacterial effector knock-in into host cells; point mutation |
Cancer
Elevated phospholipase D and diacylglycerol kinase activities increase PA levels, promoting cancer cell proliferation and survival through enhanced PA binding to mTOR and other effectors. Targeting PA-binding interfaces is being explored as a therapeutic strategy in multiple cancers.
Neurodegeneration
Disrupted PA binding in mitochondria, particularly involving RMDN3/PTPIP51, may contribute to neurodegenerative diseases by altering mitochondrial-associated membrane dynamics and calcium signaling. Autophagy suppression via PA binding to GAPC and PGK could also impair neuronal proteostasis.
Metabolic disorders
PA binding to glycolytic enzymes GAPC and PGK links lipid signaling to glucose metabolism, with implications for insulin resistance and metabolic syndrome. Seipin mutations that affect PA homeostasis at the nuclear membrane are associated with lipodystrophy and related metabolic disorders.
Infectious disease
Bacterial pathogens such as Legionella pneumophila secrete effectors like Lpg1137 that require PA binding to target host syntaxin 17, disrupting membrane trafficking and promoting infection. Understanding PA binding in host-pathogen interactions may reveal new antimicrobial targets.
From phosphatidic acid binding-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of PA binding affect mTOR signaling? | CRISPR knockout of mTOR PA-binding domain or point mutation |
| How does PA binding regulate mitochondrial dynamics? | Knock-in of tagged RMDN3/PTPIP51 with PA-binding mutation |
| What is the role of PA binding in autophagy suppression? | Overexpression of GAPC/PGK PA-binding mutants |
| How does seipin PA binding affect nuclear membrane? | Knockout and knock-in of seipin mutations |
| Can bacterial effector PA binding be targeted? | Point mutation of Lpg1137 PA-binding site in infection models |
| What is the global PA-binding proteome? | Overexpression of tagged PA-binding domains followed by mass spectrometry |
How to Study the phosphatidic acid binding Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Lipid overlay assay | Direct binding of proteins to immobilized PA | Initial screening of PA-binding candidates |
| Affinity purification + mass spectrometry | Identification of PA-binding proteins in lysates | Proteome-wide discovery |
| FRET/FLIM biosensors | Real-time PA binding dynamics in live cells | Spatiotemporal analysis |
| CRISPR knockout | Loss of function of PA-binding protein | Causal testing of PA binding in cells |
| Point mutation knock-in | Effect of specific PA-binding residue changes | Dissecting binding motifs |
| Overexpression | Gain of function or dominant-negative effects | Testing PA-binding mutants |
| Co-immunoprecipitation | Interaction between PA-binding protein and partners | Complex formation studies |
| Lipidomics | PA levels and species | Correlating binding with lipid environment |
Lipid overlay and binding assays
Lipid overlay assays using membrane-immobilized phospholipids are a classic method to detect PA binding by recombinant proteins or lysates. They allow rapid screening of candidate PA-binding proteins and mapping of binding specificity.
Mass spectrometry-based proteomics
Affinity purification with PA-conjugated beads followed by mass spectrometry enables unbiased identification of PA-binding proteins from cell lysates. Quantitative proteomics can reveal dynamic changes in PA binding under different conditions.
Fluorescence imaging and FRET
Genetically encoded PA biosensors and FRET-based probes allow real-time visualization of PA binding in live cells, revealing spatiotemporal dynamics at membranes and organelles.
Genetic screens and CRISPR
CRISPR knockout and point-mutation screens can systematically test the function of PA-binding motifs in endogenous genes, linking binding to phenotype. These approaches are complemented by overexpression of wild-type and binding-deficient mutants.
How CRISPR Can Be Used to Study GO:0070300 phosphatidic acid binding
Knockout
CRISPR knockout of genes encoding PA-binding proteins or their binding domains can abolish PA binding and reveal downstream consequences. For example, knockout of mTOR or RMDN3/PTPIP51 has been used to study PA-dependent signaling and mitochondrial dynamics.
Point Mutation
Introducing point mutations in PA-binding motifs (e.g., in the FRB domain of mTOR or the PA-binding region of RMDN3/PTPIP51) allows precise dissection of binding versus other functions. This is often achieved via CRISPR base editing or homology-directed repair.
Knock-in
Knock-in of tagged or mutant versions of PA-binding proteins (e.g., GFP-tagged seipin or RMDN3/PTPIP51) enables visualization and biochemical analysis of PA binding in endogenous contexts. Knock-in of disease-associated mutations can model human pathologies.
Overexpression
Overexpression of wild-type or PA-binding-deficient mutants of GAPC, PGK, or other proteins can test gain-of-function and dominant-negative effects on autophagy and metabolism. This approach is useful for epistasis experiments.
How EDITGENE Supports phosphatidic acid binding Research
Researchers studying phosphatidic acid binding-related genes often need to determine whether a candidate gene is causally involved in a specific pathway or disease. EDITGENE provides comprehensive CRISPR-based services to generate precisely engineered cell models, enabling functional validation of PA-binding proteins and their motifs.
Contact EDITGENE today to design your custom CRISPR model for phosphatidic acid binding research.
Frequently Asked Questions About phosphatidic acid binding
What is phosphatidic acid binding?
Phosphatidic acid binding (GO:0070300) is a molecular function where a protein selectively binds to phosphatidic acid, a glycerol phosphate with two fatty acyl chains, typically through electrostatic and hydrophobic interactions.
What genes are involved in phosphatidic acid binding?
Key genes include DGK, PLD, MTOR, RMDN3/PTPIP51, SEIPIN, GAPC, PGK, and bacterial effector Lpg1137, among others.
How does phosphatidic acid binding regulate mTOR?
PA binds to the FRB domain of mTOR, stabilizing the kinase complex at the lysosomal membrane and promoting mTORC1 activation.
What is the role of phosphatidic acid binding in autophagy?
PA binding to GAPC and PGK competitively inhibits their glycolytic functions, leading to autophagy suppression under nutrient-rich conditions.
Which diseases are linked to phosphatidic acid binding?
Dysregulated PA binding is implicated in cancer, neurodegeneration, metabolic disorders, and infectious diseases.
How can I study phosphatidic acid binding in the lab?
Common methods include lipid overlay assays, mass spectrometry, FRET biosensors, and CRISPR-based genetic models.
What are the best CRISPR models for PA-binding research?
Knockout, point mutation, knock-in, and overexpression models are all valuable; the choice depends on whether you need loss-of-function, binding-specific perturbation, or visualization.
Is phosphatidic acid binding druggable?
Yes, the PA-binding interface is considered a potential drug target, with small molecules and peptides being explored to modulate lipid-protein interactions.
What is the difference between phosphatidic acid binding and phosphatidylserine binding?
Both are anionic phospholipid binding functions, but PA binding specifically recognizes the small, cone-shaped PA headgroup, while phosphatidylserine binding recognizes a different headgroup, leading to distinct protein targets and cellular roles.
How does seipin regulate phosphatidic acid binding?
Seipin governs PA homeostasis at the inner nuclear membrane, and its loss alters the distribution and binding of PA-binding proteins, affecting nuclear envelope integrity.
Conclusion
Phosphatidic acid binding (GO:0070300) is a fundamental molecular function that connects lipid metabolism to diverse cellular processes, including mTOR signaling, autophagy, mitochondrial dynamics, and nuclear membrane homeostasis. The growing list of PA-binding proteins and their disease associations underscores the importance of this interaction in human health. CRISPR-based models are indispensable for dissecting the causal roles of PA-binding motifs, and EDITGENE provides end-to-end services to accelerate this research.
References
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- 3. Ito N et al.. 2022. MITOL regulates phosphatidic acid-binding activity of RMDN3/PTPIP51.. J Biochem 171(5):529-541 PMID: 34964862
- 4. Guan B et al.. 2022. Phosphatidic acid suppresses autophagy through competitive inhibition by binding GAPC (glyceraldehyde-3-phosphate dehydrogenase) and PGK (phosphoglycerate kinase) proteins.. Autophagy 18(11):2656-2670 PMID: 35289711
- 5. Romanauska A et al.. 2024. Seipin governs phosphatidic acid homeostasis at the inner nuclear membrane.. Nat Commun 15(1):10486 PMID: 39622802
- 6. Frias MA et al.. 2023. Regulation of mTOR by phosphatidic acid.. Trends Endocrinol Metab 34(3):170-180 PMID: 36732094
- 7. Jang JH et al.. 2012. Understanding of the roles of phospholipase D and phosphatidic acid through their binding partners.. Prog Lipid Res 51(2):71-81 PMID: 22212660
- 8. Murata M et al.. 2022. Requirement of phosphatidic acid binding for distribution of the bacterial protein Lpg1137 targeting syntaxin 17.. J Cell Sci 135(6) PMID: 35224642
