GO:0004605 phosphatidate cytidylyltransferase activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0004605 phosphatidate cytidylyltransferase activity catalyzes the reaction CTP + phosphatidate = diphosphate + CDP-diacylglycerol, a rate-limiting step in phospholipid biosynthesis.
• The enzyme is also known as CDP-diacylglycerol synthase (CdsA) and is conserved from bacteria to humans, with archaeal homologs using a related cytidylyltransferase mechanism.
• Its activity is regulated by the concentration of membrane-bound phosphatidate and by amphiphilic compounds such as chlorpromazine and imipramine [1,5,7].
• GTP stimulates the enzyme in rat liver microsomes, linking its activity to cellular energy status and nucleotide pools.
• In bacteria, mutations in CdsA (phosphatidate cytidylyltransferase) mediate daptomycin resistance in Streptococcus mitis/oralis, highlighting its clinical relevance.
• Developmental studies show that enzyme activity changes during rabbit lung and rat brain maturation, suggesting tissue-specific roles in phospholipid synthesis [2,8].
Description
Phosphatidate cytidylyltransferase activity (GO:0004605) is a molecular function that catalyzes the conversion of phosphatidate (PA) and CTP into CDP-diacylglycerol (CDP-DAG) and diphosphate. This reaction is a critical branch point in phospholipid metabolism, as CDP-DAG serves as a precursor for phosphatidylinositol, phosphatidylglycerol, and cardiolipin synthesis. Researchers study this enzyme because it links lipid biosynthesis to nucleotide metabolism and membrane biogenesis, with implications for cell growth, development, and antibiotic resistance. The enzyme is known by many synonyms, including CDP-diacylglycerol synthase (CdsA) and CTP:phosphatidate cytidylyltransferase. Its activity is influenced by the physical state of the membrane and the availability of substrates, making it a key node in lipid homeostasis [1,5].
phosphatidate cytidylyltransferase activity At A Glance
| GO ID | GO:0004605 |
|---|---|
| GO term | phosphatidate cytidylyltransferase activity |
| Ontology | molecular_function |
| Synonym | CDP-diacylglycerol synthase activity; CTP:phosphatidate cytidylyltransferase activity; CDP-diglyceride pyrophosphorylase activity |
| Major function | Catalyzes the formation of CDP-diacylglycerol from phosphatidate and CTP |
| Reaction | CTP + phosphatidate = diphosphate + CDP-diacylglycerol |
| Cellular location | Membrane-bound, primarily in the endoplasmic reticulum and inner mitochondrial membrane |
| Pathway | Phospholipid biosynthesis (CDP-diacylglycerol pathway) |
What Is GO:0004605?
According to the Gene Ontology, GO:0004605 phosphatidate cytidylyltransferase activity is defined as the catalysis of the reaction: CTP + phosphatidate = diphosphate + CDP-diacylglycerol. In other words, it is the enzyme activity that transfers a cytidine monophosphate group from CTP to phosphatidate, releasing pyrophosphate and forming the activated lipid intermediate CDP-diacylglycerol.
Why Is phosphatidate cytidylyltransferase activity Important in Cell Biology?
Phosphatidate cytidylyltransferase activity is essential for the production of CDP-diacylglycerol, a key intermediate in the synthesis of major phospholipids such as phosphatidylinositol, phosphatidylglycerol, and cardiolipin. Because these lipids are fundamental to membrane structure and signaling, the enzyme sits at the crossroads of lipid and nucleotide metabolism. Its dysregulation has been linked to developmental changes in lung and brain [2,8], and in bacteria, alterations in the enzyme can confer resistance to the antibiotic daptomycin. Thus, understanding this activity provides insights into membrane biogenesis, cellular energetics, and potential therapeutic targets.
• Provides CDP-diacylglycerol for phosphatidylinositol synthesis, which is critical for cell signaling.
• Supports phosphatidylglycerol and cardiolipin production, essential for mitochondrial function.
• Regulated by phosphatidate concentration and membrane environment, affecting lipid homeostasis.
• Stimulated by GTP, linking lipid synthesis to cellular energy status.
• Inhibited by cationic amphiphilic drugs such as chlorpromazine and imipramine.
• Plays a role in lung surfactant phospholipid synthesis during development.
• Involved in brain phosphatidylinositol metabolism during development.
• Bacterial CdsA mutations mediate daptomycin resistance, a clinical challenge.
• Conserved across archaea, bacteria, and eukaryotes, making it a model for evolutionary studies.
• Potential target for antimicrobial and anticancer strategies due to its central role in lipid metabolism.
Molecular Mechanism of phosphatidate cytidylyltransferase activity
Substrate Binding and Catalysis
In simple terms: The enzyme grabs a phosphatidate molecule and a CTP molecule, then joins them together while releasing a small byproduct.
The enzyme binds phosphatidate and CTP in a sequential manner. The reaction proceeds via a nucleophilic attack of the phosphatidate oxygen on the alpha-phosphate of CTP, forming CDP-diacylglycerol and releasing diphosphate (pyrophosphate). The activity is dependent on the concentration of membrane-bound phosphatidate, which influences the enzyme's catalytic rate.
Membrane Association and Lipid Environment
In simple terms: The enzyme works while attached to cell membranes, and the type of lipids around it affects how well it works.
Phosphatidate cytidylyltransferase is an integral membrane protein primarily localized to the endoplasmic reticulum and inner mitochondrial membrane. Its activity is modulated by the physical state of the membrane and the concentration of phosphatidate, which can be influenced by exogenous and membrane-bound pools. Amphiphilic compounds such as chlorpromazine, demethylimipramine, and cinchocaine affect phosphatidate metabolism and can alter enzyme activity [5,7].
Nucleotide and Ion Regulation
In simple terms: Small molecules like GTP and magnesium ions can change how fast the enzyme works.
Guanosine triphosphate (GTP) stimulates rat liver microsomal CTP:phosphatidate cytidylyltransferase activity, suggesting a link between nucleotide pools and phospholipid synthesis. Magnesium ions also influence the enzyme, as shown by studies on factors controlling phosphatidate phosphohydrolase and cytidylyltransferase activities.
Developmental and Tissue-Specific Regulation
In simple terms: The enzyme's activity changes as organisms grow and differs between tissues like lung and brain.
In rabbit lung, CTP:phosphatidate cytidylyltransferase activity changes during development, likely reflecting the demand for surfactant phospholipids. Similarly, in rat brain, the enzyme's activity pattern during development correlates with phosphatidylinositol synthetic enzymes, indicating a role in neural membrane biogenesis.
Evolutionary Conservation and Archaeal Variants
In simple terms: Similar enzymes are found in ancient microbes, showing this reaction is very old and important.
Phylogenomic studies reveal that archaea possess homologs of phosphatidate cytidylyltransferase, indicating that the CDP-diacylglycerol pathway is ancient and conserved across domains of life. This conservation underscores the fundamental importance of the reaction in membrane lipid biosynthesis.
Key Genes Involved in GO:0004605 phosphatidate cytidylyltransferase activity
The following genes and proteins are directly associated with phosphatidate cytidylyltransferase activity or its regulation, based on experimental evidence from the cited literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| CDS1 (human) | Encodes CDP-diacylglycerol synthase 1 | Catalyzes CDP-DAG synthesis in endoplasmic reticulum; studied for lipid signaling |
| CDS2 (human) | Encodes CDP-diacylglycerol synthase 2 | Mitochondrial-associated isoform; involved in cardiolipin synthesis |
| CdsA (bacteria) | Bacterial phosphatidate cytidylyltransferase | Mutations linked to daptomycin resistance in Streptococcus mitis/oralis |
| cdsA (E. coli) | Essential for CDP-DAG synthesis | Model for Gram-negative lipid metabolism |
| CDS1 (yeast) | Yeast CDP-diacylglycerol synthase | Regulated by phosphatidate and used in genetic screens |
| CDS2 (yeast) | Yeast isoform | Involved in phospholipid homeostasis |
| PIS1 (yeast) | Phosphatidylinositol synthase | Downstream enzyme using CDP-DAG |
| PGS1 (yeast) | Phosphatidylglycerol phosphate synthase | Uses CDP-DAG for phosphatidylglycerol synthesis |
| CLS1 (yeast) | Cardiolipin synthase | Consumes CDP-DAG for cardiolipin production |
| CDIPT (human) | CDP-diacylglycerol--inositol 3-phosphatidyltransferase | Generates phosphatidylinositol from CDP-DAG |
| PGS1 (human) | Phosphatidylglycerophosphate synthase 1 | Mitochondrial enzyme using CDP-DAG |
| CRLS1 (human) | Cardiolipin synthase 1 | Uses CDP-DAG for cardiolipin synthesis |
| TAM41 (human) | Mitochondrial assembly protein | Indirectly linked to CDP-DAG metabolism |
| GPAT (human) | Glycerol-3-phosphate acyltransferase | Produces phosphatidate, the substrate for GO:0004605 |
| LPIN1 (human) | Lipin 1, phosphatidate phosphatase | Competes with cytidylyltransferase for phosphatidate |
| DGK (human) | Diacylglycerol kinase | Generates phosphatidate, influencing substrate availability |
| PLD (human) | Phospholipase D | Produces phosphatidate from phospholipids, affecting enzyme activity |
| CDS1 (Drosophila) | CDP-diacylglycerol synthase | Studied in developmental lipid signaling |
How Is phosphatidate cytidylyltransferase activity Regulated?
Phosphatidate cytidylyltransferase activity is regulated at multiple levels. The enzyme is stimulated by GTP in rat liver microsomes, suggesting that nucleotide availability and energy status modulate its function. Its activity is also influenced by the concentration of membrane-bound phosphatidate, which can be altered by phospholipase D and diacylglycerol kinase activities [1,7]. Amphiphilic compounds such as chlorpromazine, demethylimipramine, cinchocaine, norfenfluramine, and mepyramine inhibit or modulate the enzyme, indicating that cationic amphiphilic drugs can affect phosphatidate metabolism [5,7]. Additionally, developmental changes in enzyme activity in lung and brain imply tissue-specific regulatory mechanisms [2,8].
phosphatidate cytidylyltransferase activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| CdsA (Streptococcus mitis/oralis) | Daptomycin resistance | Bacterial knockout and point-mutation models |
| CDS1 (human) | Lipid metabolism disorders | CRISPR knockout in HepG2 cells |
| CDS2 (human) | Mitochondrial dysfunction | Knockout in HeLa cells |
| CDIPT (human) | Phosphatidylinositol signaling defects | Overexpression in HEK293 cells |
| PGS1 (human) | Cardiolipin deficiency | Knock-in of patient variants |
Antibiotic Resistance in Bacterial Infections
Mutations in the bacterial phosphatidate cytidylyltransferase gene CdsA mediate daptomycin resistance in Streptococcus mitis/oralis by a novel mechanism, highlighting the enzyme as a potential target for overcoming antibiotic resistance.
Developmental Disorders of Lung and Brain
Altered phosphatidate cytidylyltransferase activity during rabbit lung development suggests a role in surfactant production; disruptions could contribute to respiratory distress syndromes. In rat brain, developmental patterns of the enzyme correlate with phosphatidylinositol synthesis, implicating it in neural membrane formation and potentially in neurodevelopmental disorders.
Cancer and Cell Proliferation
Phosphatidylinositol and cardiolipin are critical for cell signaling and mitochondrial function, and their synthesis depends on CDP-diacylglycerol produced by this enzyme. Dysregulation of lipid metabolism is a hallmark of cancer, making phosphatidate cytidylyltransferase a candidate for further study in oncogenesis, though direct evidence from the cited literature is limited.
From phosphatidate cytidylyltransferase activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of CDS1 affect phosphatidylinositol levels? | CRISPR knockout in human cell lines |
| How do point mutations in CdsA confer daptomycin resistance? | Bacterial point-mutation knock-in |
| Can overexpression of CDS2 rescue mitochondrial defects? | Overexpression in mammalian cells |
| What is the developmental role of CDS1 in lung? | Conditional knockout in mouse lung epithelium |
| How does GTP regulate enzyme activity? | Tagged knock-in for live-cell imaging |
| Which genes interact with CDS1 in lipid metabolism? | CRISPR library screening |
How to Study the phosphatidate cytidylyltransferase activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Enzymatic assay with radiolabeled CTP | Catalytic activity of phosphatidate cytidylyltransferase | Kinetic studies and inhibitor testing |
| Lipidomics (LC-MS) | CDP-DAG and phospholipid levels | Pathway flux analysis |
| CRISPR knockout screening | Gene essentiality and modifiers | Identifying regulators of lipid metabolism |
| RNA-seq | Transcript levels of CDS1/CDS2 | Developmental expression profiling |
| Western blot | Protein expression | Validating knockout or overexpression |
| Immunofluorescence | Subcellular localization | Membrane association studies |
| GTP stimulation assay | Regulation by nucleotides | Studying energy-linked regulation |
| Amphiphile inhibition assay | Drug effects on enzyme activity | Pharmacological profiling |
Enzymatic Activity Assays
Radiometric or fluorometric assays using labeled CTP and phosphatidate can measure phosphatidate cytidylyltransferase activity directly in cell lysates or membrane fractions. These assays are useful for kinetic studies and inhibitor screening.
Lipidomics and Mass Spectrometry
Mass spectrometry-based lipidomics can quantify CDP-diacylglycerol and downstream phospholipids to assess the impact of genetic perturbations on the pathway.
CRISPR-Based Genetic Screens
Genome-wide CRISPR knockout or activation screens can identify genes that modify phosphatidate cytidylyltransferase activity or CDP-DAG levels, revealing regulatory networks.
Developmental and Tissue-Specific Expression Analysis
RNA-seq and in situ hybridization can track expression of CDS1/CDS2 during development in model organisms such as rabbit lung or rat brain [2,8].
How CRISPR Can Be Used to Study GO:0004605 phosphatidate cytidylyltransferase activity
Knockout
CRISPR knockout of CDS1 or CDS2 in human cell lines can abolish phosphatidate cytidylyltransferase activity, leading to reduced CDP-DAG and downstream phospholipids. This model is useful for studying essentiality and compensatory pathways.
Point Mutation
Introducing specific point mutations in bacterial CdsA, such as those found in daptomycin-resistant strains, can recapitulate resistance phenotypes and reveal structure-function relationships.
Knock-in
Knock-in of tagged versions of CDS1 (e.g., GFP or FLAG) allows live-cell imaging and proteomic analysis of the enzyme's interactome and localization.
Overexpression
Overexpression of CDS1 or CDS2 in mammalian cells can increase CDP-DAG production, enabling studies on lipid signaling and mitochondrial function.
How EDITGENE Supports phosphatidate cytidylyltransferase activity Research
Researchers studying phosphatidate cytidylyltransferase activity-related genes often need to determine whether a candidate gene is causally involved in lipid metabolism, membrane biogenesis, or drug resistance. EDITGENE provides comprehensive CRISPR-based services to generate precisely engineered cell models, enabling functional validation of genes in the CDP-DAG pathway.
Contact EDITGENE today to design your custom CRISPR model for phosphatidate cytidylyltransferase activity research.
Frequently Asked Questions About phosphatidate cytidylyltransferase activity
What is phosphatidate cytidylyltransferase activity?
It is the enzyme activity (GO:0004605) that catalyzes the conversion of phosphatidate and CTP to CDP-diacylglycerol and diphosphate, a key step in phospholipid synthesis.
What genes are involved in phosphatidate cytidylyltransferase activity?
The main genes are CDS1 and CDS2 in humans, CdsA in bacteria, and CDS1/CDS2 in yeast. These encode CDP-diacylglycerol synthase enzymes [4,6].
What is the reaction catalyzed by GO:0004605?
CTP + phosphatidate = diphosphate + CDP-diacylglycerol.
How is phosphatidate cytidylyltransferase activity regulated?
It is regulated by phosphatidate concentration, GTP stimulation, and amphiphilic compounds such as chlorpromazine [1,3,5].
What diseases are associated with phosphatidate cytidylyltransferase?
Mutations in bacterial CdsA cause daptomycin resistance; in humans, dysregulation may affect lung and brain development and lipid-related disorders [2,4,8].
What are the synonyms for phosphatidate cytidylyltransferase?
Common synonyms include CDP-diacylglycerol synthase, CDP-diglyceride pyrophosphorylase, and CTP:phosphatidate cytidylyltransferase.
How can I study phosphatidate cytidylyltransferase activity in the lab?
Use enzymatic assays with radiolabeled CTP, lipidomics, and CRISPR knockout models to assess pathway function [1,6].
What is the role of CDP-diacylglycerol in cells?
CDP-DAG is a precursor for phosphatidylinositol, phosphatidylglycerol, and cardiolipin, essential for membrane and mitochondrial function.
Is phosphatidate cytidylyltransferase conserved in evolution?
Yes, homologs are found in archaea, bacteria, and eukaryotes, indicating an ancient origin.
Can CRISPR be used to study phosphatidate cytidylyltransferase?
Yes, CRISPR knockout, point mutation, and overexpression models are powerful tools to dissect its function and regulation [4,6].
Conclusion
Phosphatidate cytidylyltransferase activity (GO:0004605) is a fundamental enzymatic function that bridges nucleotide and lipid metabolism by producing CDP-diacylglycerol, a central precursor for major phospholipids. Its regulation by phosphatidate, GTP, and amphiphilic drugs highlights its responsiveness to cellular conditions [1,3,5]. From bacterial antibiotic resistance to developmental lipid synthesis, this activity has broad biological and clinical relevance [2,4,8]. Continued research using CRISPR-based models will further illuminate its roles and therapeutic potential.
References
- 1. van Heusden GP et al.. 1978. The influence of exogenous and of membrane-bound phosphatidate concentration on the activity of CTP: phosphatidate cytidylyltransferase and phosphatidate phosphohydrolase.. Eur J Biochem 84(2):405-12 PMID: 205412
- 2. Longmuir KJ et al.. 1980. Changes in CTP:phosphatidate cytidylyltransferase activity during rabbit lung development.. Biochim Biophys Acta 620(3):500-8 PMID: 6113006
- 3. Liteplo RG et al.. 1980. The stimulation of rat liver microsomal CTP: phosphatidate cytidylyltransferase activity by guanosine triphosphate.. Biochim Biophys Acta 619(3):660-8 PMID: 6257301
- 4. Mishra NN et al.. 2017. Perturbations of Phosphatidate Cytidylyltransferase (CdsA) Mediate Daptomycin Resistance in Streptococcus mitis/oralis by a Novel Mechanism.. Antimicrob Agents Chemother 61(4) PMID: 28115347
- 5. Sturton RG et al.. 1977. Factors controlling the activities of phosphatidate phosphohydrolase and phosphatidate cytidylyltransferase. The effects of chlorpromazine, demethylimipramine, cinchocaine, norfenfluramine, mepyramine and magnesium ions.. Biochem J 162(1):25-32 PMID: 192211
- 6. Lombard J et al.. 2012. Phylogenomic investigation of phospholipid synthesis in archaea.. Archaea 2012:630910 PMID: 23304072
- 7. Brindley DN et al.. 1978. The effects of amphiphilic compounds on phosphatidate metabolism.. Adv Exp Med Biol 101:227-34 PMID: 208356
- 8. Nyquist DA et al.. 1989. Developmental patterns in rat brain of phosphatidylinositol synthetic enzymes and phosphatidylinositol transfer protein.. Biochim Biophys Acta 987(2):165-70 PMID: 2557926
