GO:0004307 ethanolaminephosphotransferase activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0004307 ethanolaminephosphotransferase activity catalyzes the final step of the CDP-ethanolamine (Kennedy) pathway: transfer of phosphoethanolamine from CDP-ethanolamine to diacylglycerol, yielding phosphatidylethanolamine (PE) and CMP.
• The reaction is essential for de novo PE synthesis in eukaryotes; in Saccharomyces cerevisiae, the EPT1 gene encodes the major diacylglycerol ethanolaminephosphotransferase.
• Enzyme activity is membrane-bound and enriched in microsomal and synaptic plasma membrane fractions, where it can be assayed alongside other phospholipid-synthesizing enzymes.
• PE produced by this activity supports T follicular helper cell differentiation and humoral immunity, linking the enzyme to adaptive immune function.
• Defects in PE synthesis and related phospholipid metabolism are associated with muscular dystrophy (CHKB-related) and glomerular injury involving ferroptosis.
• CRISPR knockout, point-mutation, knock-in, and overexpression models enable causal dissection of ethanolaminephosphotransferase genes in cell and animal systems.
Description
Ethanolaminephosphotransferase activity (GO:0004307) is a molecular function that catalyzes the terminal step of the CDP-ethanolamine pathway for phosphatidylethanolamine (PE) biosynthesis. The reaction transfers the phosphoethanolamine moiety from CDP-ethanolamine to sn-1,2-diacylglycerol, releasing CMP and forming PE, a major zwitterionic phospholipid required for membrane integrity, cell signaling, and lipid homeostasis. Because PE is a precursor for phosphatidylcholine, glycosylphosphatidylinositol anchors, and ethanolamine plasmalogens, the enzyme sits at a metabolic branch point with broad physiological impact. Biochemical studies have characterized ethanolaminephosphotransferase activity in diverse membranes, including isolated fat cell microsomes, bovine liver microsomes, and synaptic plasma membrane vesicles. In Saccharomyces cerevisiae, genetic and biochemical work identified the EPT1 gene as encoding a diacylglycerol ethanolaminephosphotransferase, providing an early model for studying the enzyme's role in lipid metabolism. More recent work has connected PE synthesis to immune cell function, showing that metabolic control of PE in T follicular helper cells influences humoral immunity. For researchers, GO:0004307 represents both a defined enzymatic activity and a node in lipid metabolic networks that can be perturbed with CRISPR-based models. Understanding its catalytic mechanism, regulation, and disease relevance supports studies in immunology, neurobiology, and metabolic disorders.
ethanolaminephosphotransferase activity At A Glance
| GO ID | GO:0004307 |
|---|---|
| GO term | ethanolaminephosphotransferase activity |
| Ontology | molecular_function |
| Synonym | CDP-ethanolamine:1,2-diacylglycerol ethanolaminephosphotransferase activity; CDPethanolamine diglyceride phosphotransferase activity; diacylglycerol ethanolaminephosphotransferase activity; EPT; phosphorylethanolamine-glyceride transferase activity |
| Major function | Catalyzes the transfer of phosphoethanolamine from CDP-ethanolamine to 1,2-diacylglycerol, producing phosphatidylethanolamine and CMP |
| Reaction | CDP-ethanolamine + 1,2-diacylglycerol = CMP + a phosphatidylethanolamine |
| Pathway | CDP-ethanolamine (Kennedy) pathway for phosphatidylethanolamine biosynthesis |
| Cellular location | Membrane-bound; enriched in microsomal and synaptic plasma membrane fractions |
| Representative gene | Saccharomyces cerevisiae EPT1; mammalian homologs include SELENOI (EPT1) and CHPT1-related enzymes |
What Is GO:0004307?
Ethanolaminephosphotransferase activity (GO:0004307) is defined as catalysis of the reaction: CDP-ethanolamine + 1,2-diacylglycerol = CMP + a phosphatidylethanolamine. In other words, the enzyme transfers the phosphoethanolamine group from CDP-ethanolamine to a diacylglycerol acceptor, forming phosphatidylethanolamine and releasing CMP. This activity is synonymous with CDP-ethanolamine:1,2-diacylglycerol ethanolaminephosphotransferase, CDPethanolamine diglyceride phosphotransferase, diacylglycerol ethanolaminephosphotransferase, EPT, and phosphorylethanolamine-glyceride transferase. It is a molecular_function term in the Gene Ontology and represents the committed step for PE synthesis via the Kennedy pathway.
Why Is ethanolaminephosphotransferase activity Important in Cell Biology?
Ethanolaminephosphotransferase activity is critical because it produces phosphatidylethanolamine (PE), one of the most abundant phospholipids in eukaryotic membranes. PE is required for membrane biogenesis, protein folding, and cell signaling, and it serves as a precursor for phosphatidylcholine and glycosylphosphatidylinositol anchors. The enzyme therefore sits at the intersection of lipid metabolism, immune function, and disease. Studies in T follicular helper cells have shown that PE metabolism controls humoral immunity, highlighting the physiological importance of this activity. In addition, defects in PE synthesis or related phospholipid remodeling have been linked to muscular dystrophy and glomerular injury, underscoring its relevance to human disease.
• Produces phosphatidylethanolamine (PE), a major membrane phospholipid essential for cell viability.
• Represents the final committed step of the CDP-ethanolamine (Kennedy) pathway for PE synthesis.
• Supports T follicular helper cell differentiation and humoral immunity through metabolic control of PE.
• Provides PE precursors for phosphatidylcholine and glycosylphosphatidylinositol anchor biosynthesis.
• Enzyme activity is detectable in microsomes, fat cells, and synaptic plasma membranes, enabling biochemical assays.
• The yeast EPT1 gene provides a genetically tractable model for studying the enzyme's function.
• Altered PE metabolism is associated with CHKB-related muscular dystrophy.
• PE-related lipid peroxidation and ferroptosis contribute to hypertensive glomerular lesions.
• The enzyme is a potential target for modulating membrane lipid composition in disease models.
• CRISPR-based editing of ethanolaminephosphotransferase genes enables causal studies in immunology and metabolism.
Molecular Mechanism of ethanolaminephosphotransferase activity
Substrate recognition and binding
In simple terms: The enzyme grabs two molecules: CDP-ethanolamine and diacylglycerol.
Ethanolaminephosphotransferase activity requires two substrates: CDP-ethanolamine, which donates the phosphoethanolamine group, and sn-1,2-diacylglycerol, which serves as the lipid acceptor. The enzyme is membrane-bound, and its active site is positioned to access both the aqueous nucleotide sugar and the hydrophobic diacylglycerol within the membrane bilayer. Biochemical purification from bovine liver microsomes has provided evidence for a distinct protein responsible for this activity.
Catalytic transfer and product formation
In simple terms: The enzyme moves the phosphoethanolamine part onto diacylglycerol, making phosphatidylethanolamine and CMP.
The catalytic mechanism involves nucleophilic attack by the hydroxyl group of diacylglycerol on the β-phosphate of CDP-ethanolamine, resulting in the formation of phosphatidylethanolamine and the release of CMP. This reaction is analogous to the cholinephosphotransferase step in phosphatidylcholine synthesis, and both activities can be measured in microsomal fractions. The reaction is the terminal step of the CDP-ethanolamine pathway, committing the lipid to PE formation.
Membrane environment and cofactor requirements
In simple terms: The enzyme works best in a membrane and may need specific ions or lipids around it.
Ethanolaminephosphotransferase activity is influenced by its phospholipid environment and by cations. Studies in synaptic plasma membrane vesicles showed that transferase activity is affected by the surrounding phospholipids and by certain cations, supporting the idea that the enzyme functions optimally within a specific membrane context. The activity has been compared with other membrane-bound enzymes such as sialidase and ouabain-sensitive Na+,K+-ATPase in the same vesicles, indicating that it is an integral membrane protein.
Regulation by metabolic demand
In simple terms: The cell adjusts this enzyme's activity based on how much phosphatidylethanolamine it needs.
The flux through ethanolaminephosphotransferase activity is regulated by the availability of CDP-ethanolamine and diacylglycerol, as well as by the demand for PE in membrane biogenesis and signaling. In T follicular helper cells, metabolic control of PE synthesis influences cell differentiation and humoral immunity, suggesting that the activity is coupled to immune cell state. In yeast, the EPT1 gene is required for efficient PE synthesis, and mutants lacking it show altered lipid metabolism.
Tissue-specific expression and isoforms
In simple terms: Different tissues may use different versions of the enzyme.
Ethanolaminephosphotransferase activity has been detected in diverse tissues, including fat cells, liver, and brain synaptic membranes. The existence of multiple isoforms or related enzymes is suggested by biochemical differences and by the identification of the yeast EPT1 gene, which encodes a diacylglycerol ethanolaminephosphotransferase. In mammals, the enzyme SELENOI (also known as EPT1) is a selenoprotein that can catalyze this activity, linking it to selenium metabolism.
Key Genes Involved in GO:0004307 ethanolaminephosphotransferase activity
The following genes and proteins are directly or functionally linked to ethanolaminephosphotransferase activity (GO:0004307) based on published biochemical and genetic studies.
| Gene | Major Role | Research Relevance |
|---|---|---|
| EPT1 (Saccharomyces cerevisiae) | Encodes diacylglycerol ethanolaminephosphotransferase; major enzyme for PE synthesis in yeast | Model for genetic dissection of the Kennedy pathway; mutants available for lipid studies |
| SELENOI (EPT1, human) | Selenoprotein with ethanolaminephosphotransferase activity; catalyzes CDP-ethanolamine to PE | Links PE synthesis to selenium metabolism and immune function |
| CHPT1 | Cholinephosphotransferase; related enzyme in phosphatidylcholine synthesis | Comparative studies of phosphotransferase specificity |
| CEPT1 | Choline/ethanolaminephosphotransferase; can use both CDP-choline and CDP-ethanolamine | Bifunctional enzyme in phospholipid synthesis; potential redundancy |
| CHKB | Choline kinase beta; upstream of CDP-ethanolamine pathway | Mutations cause muscular dystrophy; affects PE synthesis |
| ETNK1 | Ethanolamine kinase; phosphorylates ethanolamine to phosphoethanolamine | Upstream step in CDP-ethanolamine pathway |
| ETNK2 | Ethanolamine kinase 2; isoform with tissue-specific expression | Potential regulator of PE synthesis |
| PCYT2 | CTP:phosphoethanolamine cytidylyltransferase; forms CDP-ethanolamine | Rate-limiting step in PE synthesis |
| SELENOI (alternative name) | See SELENOI; catalyzes final step of PE synthesis | Target for CRISPR knockout in immune cells |
| PEMT | Phosphatidylethanolamine N-methyltransferase; converts PE to PC | Consumes PE produced by ethanolaminephosphotransferase |
| PLA2G6 | Phospholipase A2; remodels PE | Affects PE turnover and membrane composition |
| GPX4 | Glutathione peroxidase 4; protects against lipid peroxidation | PE oxidation and ferroptosis linked to glomerular injury |
| ACSL4 | Acyl-CoA synthetase long-chain family member 4; promotes PE oxidation | Ferroptosis regulator; interacts with PE metabolism |
| B2GPI (APOH) | Beta-2 glycoprotein I; autoantibody target | Anti-B2GPI antibodies trigger ferroptosis in hypertensive glomerular lesions |
| TFH cell markers (BCL6, IL21) | T follicular helper cell transcription factors and cytokines | PE metabolism controls TFH differentiation and humoral immunity |
| CDP-ethanolamine pathway enzymes | ETNK1, PCYT2, SELENOI, CEPT1 | Coordinate PE synthesis; targets for metabolic engineering |
| Kennedy pathway enzymes | ETNK1, PCYT2, SELENOI/CEPT1, CHPT1 | Integrated pathway for phospholipid biosynthesis |
| Sialidase (NEU1) | Membrane enzyme compared with ethanolaminephosphotransferase in vesicles | Control for membrane enzyme assays |
How Is ethanolaminephosphotransferase activity Regulated?
Ethanolaminephosphotransferase activity is regulated by substrate availability, membrane lipid composition, and cellular demand for phosphatidylethanolamine. The enzyme requires CDP-ethanolamine, which is produced by the sequential actions of ethanolamine kinase (ETNK1/2) and CTP:phosphoethanolamine cytidylyltransferase (PCYT2), and diacylglycerol, which is derived from phosphatidic acid dephosphorylation. In synaptic plasma membrane vesicles, transferase activity is influenced by cations and the surrounding phospholipid environment, indicating that membrane composition modulates enzyme function. In immune cells, PE metabolism is coupled to T follicular helper cell differentiation, suggesting that the activity is regulated during immune responses. In yeast, the EPT1 gene is required for efficient PE synthesis, and its expression may be controlled by lipid metabolic signals.
ethanolaminephosphotransferase activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| CHKB | CHKB-related muscular dystrophy | Knockout or point-mutation in muscle cell lines; mouse models |
| SELENOI (EPT1) | Immune regulation; humoral immunity | CRISPR knockout in T cells; overexpression in cell lines |
| GPX4 | Ferroptosis; hypertensive glomerular lesions | Knockout in kidney cells; lipid peroxidation assays |
| ACSL4 | Ferroptosis; PE oxidation | Knockout in glomerular cells; ferroptosis induction |
| B2GPI (APOH) | Autoantibody-mediated glomerular injury | Knock-in of autoantibody; passive transfer models |
Muscular dystrophy and CHKB deficiency
CHKB encodes choline kinase beta, an enzyme in the CDP-ethanolamine pathway that also affects phosphatidylethanolamine synthesis. Mutations in CHKB cause a congenital muscular dystrophy with mitochondrial structural abnormalities. Although CHKB is not ethanolaminephosphotransferase itself, its deficiency alters the balance of phospholipid synthesis, highlighting the importance of the pathway in muscle function.
Hypertensive glomerular lesions and ferroptosis
B cell-derived anti-beta 2 glycoprotein I antibodies mediate hyperhomocysteinemia-aggravated hypertensive glomerular lesions by triggering ferroptosis, a form of cell death driven by lipid peroxidation of polyunsaturated fatty acid-containing phospholipids such as phosphatidylethanolamine. This links PE metabolism, including the activity of ethanolaminephosphotransferase, to kidney injury and oxidative stress.
Immune regulation and humoral immunity
Metabolic control of T follicular helper cells by phosphatidylethanolamine is essential for humoral immunity. PE produced through the CDP-ethanolamine pathway supports TFH cell differentiation and antibody responses, suggesting that ethanolaminephosphotransferase activity contributes to immune regulation. Dysregulation of this pathway could impact vaccine responses and autoimmune conditions.
From ethanolaminephosphotransferase activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of ethanolaminephosphotransferase reduce PE synthesis? | CRISPR knockout of SELENOI/EPT1 in HEK293 or HeLa cells |
| Does a point mutation in the catalytic site abolish enzyme activity? | Point-mutation knock-in of catalytic residues in SELENOI |
| Can tagged enzyme be used for localization studies? | Knock-in of fluorescent or epitope tag at the endogenous locus |
| Does overexpression increase PE levels and affect immune cell function? | Overexpression of SELENOI in T cell lines or primary T cells |
| Which genes compensate for loss of ethanolaminephosphotransferase? | CRISPR library screening in knockout background |
| Does PE metabolism regulate TFH differentiation? | Knockout of SELENOI in mouse models followed by immunization |
How to Study the ethanolaminephosphotransferase activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Radiolabeled enzyme assay | Ethanolaminephosphotransferase activity | Biochemical characterization in membrane fractions |
| Lipidomics (LC-MS) | Phosphatidylethanolamine species and other lipids | Quantifying PE changes after gene editing |
| CRISPR knockout screening | Genes required for PE synthesis or cell fitness | Identifying synthetic lethal partners |
| Fluorescence microscopy | Subcellular localization of tagged enzyme | Determining organelle distribution |
| Western blot | Protein expression levels | Validating knockout or overexpression |
| qRT-PCR | mRNA expression of pathway genes | Assessing transcriptional regulation |
| Ferroptosis assays | Lipid peroxidation and cell death | Linking PE metabolism to oxidative stress |
| Immunoprecipitation | Protein-protein interactions | Identifying enzyme complexes |
Biochemical enzyme assays
Ethanolaminephosphotransferase activity can be measured in membrane fractions using radiolabeled CDP-ethanolamine and diacylglycerol, followed by lipid extraction and thin-layer chromatography to quantify phosphatidylethanolamine formation. This approach has been used in fat cell microsomes, liver microsomes, and synaptic plasma membrane vesicles.
Lipidomics and mass spectrometry
Mass spectrometry-based lipidomics enables comprehensive quantification of phosphatidylethanolamine species and related phospholipids in cells and tissues. This method can reveal changes in PE levels upon genetic perturbation of ethanolaminephosphotransferase genes.
CRISPR-based genetic screens
Genome-wide CRISPR knockout or activation screens can identify genes that modulate ethanolaminephosphotransferase activity or PE dependence. Such screens are useful for uncovering synthetic lethal interactions and compensatory pathways.
Fluorescence imaging and subcellular localization
Tagged versions of ethanolaminephosphotransferase enzymes can be visualized by fluorescence microscopy to determine subcellular localization, typically to the endoplasmic reticulum and nuclear envelope. Co-localization with organelle markers confirms membrane topology.
How CRISPR Can Be Used to Study GO:0004307 ethanolaminephosphotransferase activity
Knockout
CRISPR knockout of ethanolaminephosphotransferase genes such as SELENOI or EPT1 can abolish enzyme activity, leading to reduced phosphatidylethanolamine levels and altered membrane composition. Knockout cell lines are valuable for studying the consequences of PE depletion on cell growth, signaling, and immune function.
Point Mutation
Point mutations can be introduced into catalytic residues of ethanolaminephosphotransferase to dissect the enzymatic mechanism. For example, mutating the active-site histidine or aspartate can abolish transferase activity while preserving protein expression, allowing separation of catalytic and structural functions.
Knock-in
Knock-in of epitope tags, fluorescent proteins, or conditional alleles at the endogenous locus enables precise tracking of ethanolaminephosphotransferase expression and localization. This approach avoids artifacts from overexpression and provides physiological context.
Overexpression
Overexpression of ethanolaminephosphotransferase genes can increase PE synthesis and alter membrane lipid composition. This is useful for gain-of-function studies, such as testing whether increased PE levels enhance T follicular helper cell differentiation or protect against ferroptosis.
How EDITGENE Supports ethanolaminephosphotransferase activity Research
Researchers studying ethanolaminephosphotransferase activity-related genes often need to determine whether a candidate gene is causally involved in phosphatidylethanolamine synthesis, immune regulation, or disease. EDITGENE provides CRISPR-based cell models and screening services to accelerate this discovery process.
Contact EDITGENE today to design your custom CRISPR model for ethanolaminephosphotransferase activity research.
Frequently Asked Questions About ethanolaminephosphotransferase activity
What is ethanolaminephosphotransferase activity?
Ethanolaminephosphotransferase activity (GO:0004307) is the enzymatic activity that catalyzes the transfer of phosphoethanolamine from CDP-ethanolamine to 1,2-diacylglycerol, producing phosphatidylethanolamine and CMP.
What genes are involved in ethanolaminephosphotransferase activity?
Key genes include SELENOI (EPT1) in mammals and EPT1 in Saccharomyces cerevisiae, which encode enzymes with this activity. Other pathway genes include ETNK1, PCYT2, and CEPT1.
What is the reaction catalyzed by ethanolaminephosphotransferase?
The reaction is: CDP-ethanolamine + 1,2-diacylglycerol = CMP + a phosphatidylethanolamine.
Where is ethanolaminephosphotransferase located in the cell?
The enzyme is membrane-bound and enriched in microsomal fractions and synaptic plasma membranes, consistent with its role in lipid synthesis at the endoplasmic reticulum.
How is ethanolaminephosphotransferase activity measured?
It is typically measured using radiolabeled CDP-ethanolamine and diacylglycerol in membrane fractions, followed by lipid extraction and thin-layer chromatography.
What diseases are linked to ethanolaminephosphotransferase activity?
Altered phosphatidylethanolamine metabolism is linked to CHKB-related muscular dystrophy and hypertensive glomerular lesions involving ferroptosis.
Does ethanolaminephosphotransferase affect the immune system?
Yes, phosphatidylethanolamine produced through this pathway supports T follicular helper cell differentiation and humoral immunity.
Can CRISPR be used to study ethanolaminephosphotransferase?
Yes, CRISPR knockout, point mutation, knock-in, and overexpression models enable precise dissection of gene function in this pathway.
What is the yeast EPT1 gene?
EPT1 in Saccharomyces cerevisiae encodes a diacylglycerol ethanolaminephosphotransferase, providing a genetic model for studying phosphatidylethanolamine synthesis.
How does ethanolaminephosphotransferase relate to ferroptosis?
Phosphatidylethanolamine is a substrate for lipid peroxidation during ferroptosis, and anti-B2GPI antibodies trigger ferroptosis in hypertensive glomerular lesions.
Conclusion
Ethanolaminephosphotransferase activity (GO:0004307) is a central enzymatic step in phosphatidylethanolamine biosynthesis, with essential roles in membrane biology, immune function, and disease. Its reaction mechanism, regulation, and genetic determinants are well supported by biochemical and genetic studies. Dysregulation of this activity or the broader CDP-ethanolamine pathway contributes to muscular dystrophy and glomerular injury, highlighting its clinical relevance. CRISPR-based models, including knockout, point mutation, knock-in, and overexpression, provide powerful tools to dissect the causal roles of ethanolaminephosphotransferase genes in health and disease. EDITGENE offers comprehensive services to generate these models and support mechanistic and translational research in lipid metabolism.
References
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- 3. Maurice A et al.. 1990. Phosphatidylethanolamine-ceramide-ethanolaminephosphotransferase activity in synaptic plasma membrane vesicles: Comparison with sialidase and ouabain-sensitive (Na(+), K(+))ATPase activities.. Neurochem Int 17(1):83-91 PMID: 20504606
- 4. Hjelmstad RH et al.. 1988. The sn-1,2-diacylglycerol ethanolaminephosphotransferase activity of Saccharomyces cerevisiae. Isolation of mutants and cloning of the EPT1 gene.. J Biol Chem 263(36):19748-57 PMID: 2848840
- 5. Du X et al.. 2023. B cell-derived anti-beta 2 glycoprotein I antibody mediates hyperhomocysteinemia-aggravated hypertensive glomerular lesions by triggering ferroptosis.. Signal Transduct Target Ther 8(1):103 PMID: 36907919
- 6. Coleman R et al.. 1977. Phospholipid synthesis in isolated fat cells. Studies of microsomal diacylglycerol cholinephosphotransferase and diacylglycerol ethanolaminephosphotransferase activities.. J Biol Chem 252(9):3050-6 PMID: 192727
- 7. Mancini A et al.. 1999. Purification of ethanolaminephosphotransferase from bovine liver microsomes.. Biochim Biophys Acta 1437(1):80-92 PMID: 9931448
- 8. Maurice A et al.. 1993. Phosphatidylethanolamine: ceramide-ethanolaminephosphotransferase activity in synaptic plasma membrane vesicles. Influence of some cations and phospholipid environment on transferase activity. Further proof of its location.. Int J Biochem 25(8):1183-7 PMID: 8405660
