GO:0003882 CDP-diacylglycerol-serine O-phosphatidyltransferase activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0003882 defines the enzymatic activity that transfers phosphatidyl from CDP-diacylglycerol to L-serine, producing phosphatidylserine and CMP [1, 6].
• This activity is catalyzed by phosphatidylserine synthases (PSS1 and PSS2 in humans, Pss1 in yeast, PssA in bacteria) and is essential for phospholipid biosynthesis [1, 2, 5, 8].
• Structural studies reveal a conserved catalytic mechanism involving a conserved histidine and a phosphatidyl-enzyme intermediate [6, 8].
• Loss or inhibition of this activity alters membrane lipid composition and affects LDL uptake and SREBP pathways [1, 5].
• The reaction is a key branch point in phospholipid metabolism, linking CDP-diacylglycerol to phosphatidylserine, phosphatidylethanolamine, and phosphatidylcholine [2, 4].
• CRISPR-based knockout, point mutation, and overexpression models are powerful tools to dissect the physiological roles of this activity in health and disease [1, 5].
Description
CDP-diacylglycerol-serine O-phosphatidyltransferase activity (GO:0003882) is a molecular function that catalyzes the formation of phosphatidylserine from CDP-diacylglycerol and L-serine, releasing CMP [1, 6]. This reaction is the committed step in phosphatidylserine biosynthesis in bacteria, yeast, and mammals, and it is essential for maintaining membrane phospholipid asymmetry and for providing precursors for phosphatidylethanolamine and phosphatidylcholine [2, 4]. The enzyme responsible, phosphatidylserine synthase (PSS), is conserved across evolution and has been structurally and biochemically characterized in organisms ranging from Escherichia coli to humans [6, 8]. In humans, two isoforms, PSS1 (PTDSS1) and PSS2 (PTDSS2), exhibit distinct substrate specificities and regulatory roles [1, 5]. Because phosphatidylserine is a key signaling lipid and a component of the plasma membrane, dysregulation of this activity has been linked to metabolic disorders and cancer [1, 5]. Understanding the molecular mechanism, regulation, and disease relevance of GO:0003882 is therefore of broad interest to cell biologists, biochemists, and translational researchers.
CDP-diacylglycerol-serine O-phosphatidyltransferase activity At A Glance
| GO ID | GO:0003882 |
|---|---|
| GO term | CDP-diacylglycerol-serine O-phosphatidyltransferase activity |
| Ontology | molecular_function |
| Synonym | phosphatidylserine synthase activity; PS synthase activity; CDP-diacylglycerol:L-serine 3-O-phosphatidyltransferase activity |
| Major function | Catalyzes the formation of phosphatidylserine from CDP-diacylglycerol and L-serine, releasing CMP |
| Reaction | CDP-diacylglycerol + L-serine = CMP + O-sn-phosphatidyl-L-serine |
| Enzyme class | Transferase; transferring phosphorus-containing groups |
| Organisms | Bacteria, yeast, mammals |
| Subcellular location | Endoplasmic reticulum membrane (eukaryotes); inner membrane (bacteria) |
What Is GO:0003882?
GO:0003882 describes the catalytic activity of an enzyme that transfers a phosphatidyl group from CDP-diacylglycerol to the hydroxyl group of L-serine, yielding O-sn-phosphatidyl-L-serine (phosphatidylserine) and CMP [1, 6]. This activity is synonymous with phosphatidylserine synthase activity and represents the primary route for phosphatidylserine synthesis in many organisms [2, 4].
Why Is CDP-diacylglycerol-serine O-phosphatidyltransferase activity Important in Cell Biology?
GO:0003882 is critical because it initiates the synthesis of phosphatidylserine, a phospholipid that is essential for membrane integrity, cell signaling, and apoptosis [1, 2]. Phosphatidylserine is also the precursor for phosphatidylethanolamine and phosphatidylcholine, making this activity a central node in lipid metabolism [2, 4]. In humans, the two PSS isoforms have distinct roles: PSS1 is involved in lipoprotein metabolism, and its inhibition promotes LDL uptake, while PSS2 regulates SREBP pathways [1, 5]. Consequently, this activity is a potential therapeutic target for dyslipidemia and cancer.
• Provides the major route for phosphatidylserine synthesis in bacteria, yeast, and mammals [1, 2, 4].
• Phosphatidylserine is a key component of the plasma membrane and a signal for apoptosis.
• Links CDP-diacylglycerol metabolism to phosphatidylethanolamine and phosphatidylcholine biosynthesis [2, 4].
• Human PSS1 inhibition increases LDL uptake, suggesting a role in cholesterol homeostasis.
• Human PSS2 regulates SREBP pathways, impacting lipid synthesis.
• Mutations or dysregulation may contribute to metabolic disorders and cancer [1, 5].
• Conserved mechanism across species makes it a model for studying lipid enzymes [6, 8].
• Target for antimicrobial drug development in pathogens like Candida albicans.
• Essential for membrane biogenesis in rapidly dividing cells.
• Structural insights enable rational design of inhibitors [6, 8].
What Happens During CDP-diacylglycerol-serine O-phosphatidyltransferase activity?
Substrate Binding and Recognition
In simple terms: The enzyme grabs its two starting materials, CDP-diacylglycerol and serine, and holds them in place.
The enzyme binds CDP-diacylglycerol and L-serine in a sequential manner. Structural studies of bacterial and human phosphatidylserine synthases have identified key residues that recognize the CDP-diacylglycerol headgroup and the serine moiety [6, 8]. In E. coli PssA, a conserved histidine residue acts as a nucleophile, and substrate binding induces conformational changes that position the reactants for catalysis. Similarly, the human PSS1 structure reveals a conserved catalytic site with a histidine that is essential for activity.
Catalytic Mechanism and Phosphatidyl-Enzyme Intermediate
In simple terms: The enzyme temporarily attaches the phosphatidyl group to itself, then transfers it to serine.
The reaction proceeds via a ping-pong mechanism in which the phosphatidyl group from CDP-diacylglycerol is first transferred to a conserved histidine residue, forming a covalent phosphatidyl-enzyme intermediate and releasing CMP [6, 8]. The phosphatidyl group is then transferred to the hydroxyl group of L-serine, yielding phosphatidylserine. This mechanism is conserved among CDP-DAG alcohol O-phosphatidyl transferases.
Product Release and Membrane Insertion
In simple terms: The finished phosphatidylserine is released into the membrane where it can be used or modified further.
After catalysis, phosphatidylserine is released into the membrane bilayer. In eukaryotes, the enzyme is located in the endoplasmic reticulum membrane, and the product can be subsequently decarboxylated to phosphatidylethanolamine or methylated to phosphatidylcholine [2, 4]. In bacteria, phosphatidylserine is synthesized in the inner membrane and is essential for membrane function.
Regulation by Phosphatidate Phosphatase and Lipid Precursors
In simple terms: The supply of starting materials controls how fast the reaction can go.
The activity of phosphatidylserine synthase is regulated by the availability of its substrate CDP-diacylglycerol, which is synthesized from phosphatidic acid. Phosphatidate phosphatase (Pah1 in yeast) controls the pool of phosphatidic acid and thus indirectly regulates phosphatidylserine synthesis. In yeast, the expression and activity of Pss1 are also regulated in response to inositol and choline.
Key Genes Involved in GO:0003882 CDP-diacylglycerol-serine O-phosphatidyltransferase activity
The following genes encode proteins that catalyze or regulate CDP-diacylglycerol-serine O-phosphatidyltransferase activity across model organisms and humans.
| Gene | Major Role | Research Relevance |
|---|---|---|
| PTDSS1 (PSS1) | Human phosphatidylserine synthase 1; catalyzes CDP-diacylglycerol-serine O-phosphatidyltransferase activity | Inhibition promotes LDL uptake; target for dyslipidemia |
| PTDSS2 (PSS2) | Human phosphatidylserine synthase 2; catalyzes same activity with different substrate specificity | Regulates SREBP pathways; involved in lipid homeostasis |
| PSS1 (yeast CHO1) | Yeast phosphatidylserine synthase; essential for phosphatidylserine synthesis | Model for phospholipid regulation and membrane biogenesis [2, 4] |
| PssA (E. coli) | Bacterial phosphatidylserine synthase; catalyzes the reaction in bacteria | Structural and mechanistic studies |
| Pss (C. albicans) | Phosphatidylserine synthase in Candida albicans | Antifungal target; substrate-binding site mapping |
| archaetidylserine synthase | Archaeal enzyme that uses CDP-2,3-di-O-geranylgeranyl-sn-glycerol and L-serine | Model for archaeal lipid biosynthesis |
| PAH1 (yeast) | Phosphatidate phosphatase; regulates CDP-diacylglycerol supply | Regulates phosphatidylserine synthesis via lipid precursors |
| CDS1 (yeast) | CDP-diacylglycerol synthase; produces substrate for Pss1 | Controls substrate availability |
| PTDSS1 variants | Mutations in PTDSS1 linked to Lenz-Majewski syndrome | Disease model for skeletal and lipid abnormalities |
| PTDSS2 | Phosphatidylserine synthase 2 | Regulation of SREBP and lipid metabolism |
| PSS1 (mammalian) | Phosphatidylserine synthase 1 | Structural and functional studies |
| PSS2 (mammalian) | Phosphatidylserine synthase 2 | Structural and functional studies |
| PssA homologs | Bacterial phosphatidylserine synthases | Antibacterial target |
| CHO1 | Yeast phosphatidylserine synthase gene | Classic model for phospholipid synthesis |
| PSS1 (C. albicans) | Phosphatidylserine synthase in Candida albicans | Antifungal drug discovery |
| PSS (archaea) | Archaetidylserine synthase | Archaeal membrane lipid biosynthesis |
| PTDSS1 (human) | Phosphatidylserine synthase 1 | LDL uptake and cholesterol metabolism |
| PTDSS2 (human) | Phosphatidylserine synthase 2 | SREBP regulation |
How Is CDP-diacylglycerol-serine O-phosphatidyltransferase activity Regulated?
The activity of CDP-diacylglycerol-serine O-phosphatidyltransferase is regulated at multiple levels. In yeast, the availability of CDP-diacylglycerol, which is synthesized by CDP-diacylglycerol synthase (Cds1), controls the flux through the reaction. Phosphatidate phosphatase (Pah1) modulates the pool of phosphatidic acid, thereby affecting CDP-diacylglycerol synthesis and downstream phosphatidylserine production. In humans, PSS1 and PSS2 are differentially regulated: PSS1 is inhibited by phosphatidylserine itself, while PSS2 is regulated by SREBP transcription factors [1, 5]. Additionally, the expression of PSS genes in yeast is regulated by inositol and choline, which affect phospholipid biosynthesis.
CDP-diacylglycerol-serine O-phosphatidyltransferase activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| PTDSS1 | Lenz-Majewski syndrome; dyslipidemia | Knockout and point-mutation cell lines; LDL uptake assays |
| PTDSS2 | SREBP pathway regulation; metabolic disorders | Overexpression and knockout models; lipid profiling |
| PSS1 (yeast) | Phospholipid metabolism defects | Yeast deletion mutants; complementation assays [2, 4] |
| PssA (E. coli) | Bacterial membrane integrity | Bacterial knockout and structural studies |
| Pss (C. albicans) | Fungal pathogenesis | Antifungal susceptibility testing; enzyme inhibition |
Dyslipidemia and Cardiovascular Disease
Inhibition of human PSS1 promotes LDL uptake, suggesting that reducing CDP-diacylglycerol-serine O-phosphatidyltransferase activity could lower plasma cholesterol. This links the enzyme to dyslipidemia and cardiovascular disease risk.
Lenz-Majewski Syndrome
Mutations in PTDSS1, which encodes PSS1, cause Lenz-Majewski syndrome, a rare disorder characterized by skeletal abnormalities, intellectual disability, and distinctive facial features. This highlights the importance of this activity in human development.
Cancer and Cell Proliferation
Phosphatidylserine is essential for rapidly dividing cells, and altered phosphatidylserine metabolism has been observed in cancer [1, 5]. Targeting this activity may offer therapeutic opportunities.
Metabolic Regulation via SREBP
PSS2 regulates SREBP pathways, which control lipid synthesis. Dysregulation of this activity may contribute to metabolic disorders such as fatty liver disease.
From CDP-diacylglycerol-serine O-phosphatidyltransferase activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| What is the effect of complete loss of PSS1 on cell viability? | CRISPR knockout of PTDSS1 in human cell lines |
| How do disease-associated mutations affect enzyme activity? | Point mutation knock-in of PTDSS1 variants |
| Can overexpression of PSS2 alter SREBP signaling? | Overexpression of PTDSS2 in hepatocytes |
| What is the subcellular localization of PSS1? | Tagged knock-in of PTDSS1 with fluorescent protein |
| How does PssA contribute to bacterial membrane synthesis? | Bacterial knockout and complementation |
| What is the role of Pss1 in yeast phospholipid regulation? | Yeast deletion and overexpression [2, 4] |
How to Study the CDP-diacylglycerol-serine O-phosphatidyltransferase activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| In vitro enzyme assay | Catalytic activity of phosphatidylserine synthase | Kinetic studies and inhibitor testing |
| Lipidomics (LC-MS) | Phosphatidylserine and related lipid levels | Assessing metabolic changes in knockout cells |
| Cryo-EM | 3D structure of enzyme-substrate complexes | Mechanistic insights |
| X-ray crystallography | Atomic structure of enzyme | Substrate binding and catalysis |
| CRISPR knockout | Loss-of-function phenotypes | Gene function studies |
| Overexpression | Gain-of-function effects | Regulation of SREBP pathways |
| RNA-seq | Transcriptional changes | Pathway analysis upon perturbation |
| Immunofluorescence | Subcellular localization | ER localization of PSS1 |
Enzymatic Activity Assays
CDP-diacylglycerol-serine O-phosphatidyltransferase activity can be measured using radiolabeled substrates or by monitoring CMP release. In vitro assays with purified enzyme or membrane fractions are standard [6, 8].
Lipidomics and Mass Spectrometry
Mass spectrometry-based lipidomics allows quantification of phosphatidylserine and other phospholipids to assess the impact of genetic perturbations on this activity [1, 5].
Structural Biology (Cryo-EM and X-ray Crystallography)
Crystal structures of bacterial and human phosphatidylserine synthases have revealed the catalytic mechanism and substrate binding sites [6, 8]. Cryo-EM can be used for larger complexes.
CRISPR Screening and Functional Genomics
Genome-wide CRISPR knockout screens can identify genes that modulate sensitivity to inhibitors of this activity or that regulate phosphatidylserine levels [1, 5].
How CRISPR Can Be Used to Study GO:0003882 CDP-diacylglycerol-serine O-phosphatidyltransferase activity
Knockout
CRISPR knockout of PTDSS1 or PTDSS2 in human cell lines can reveal their essentiality and impact on lipid metabolism. For example, PTDSS1 knockout reduces phosphatidylserine levels and affects LDL uptake.
Point Mutation
Introducing disease-associated point mutations (e.g., in PTDSS1) via CRISPR base editing or homology-directed repair allows functional assessment of specific residues in catalysis or regulation.
Knock-in
Knock-in of tagged versions of PSS1 or PSS2 (e.g., GFP or HA) enables localization and interaction studies without altering endogenous regulation.
Overexpression
CRISPR activation (CRISPRa) or lentiviral overexpression of PTDSS2 can be used to study its role in SREBP pathway regulation and lipid synthesis.
How EDITGENE Supports CDP-diacylglycerol-serine O-phosphatidyltransferase activity Research
Researchers studying CDP-diacylglycerol-serine O-phosphatidyltransferase activity-related genes often need to determine whether a candidate gene is causally involved in lipid metabolism, membrane biology, or disease. EDITGENE provides comprehensive CRISPR-based services to generate precisely engineered cell models for such investigations.
Contact EDITGENE today to design your custom CRISPR model for CDP-diacylglycerol-serine O-phosphatidyltransferase activity research.
Frequently Asked Questions About CDP-diacylglycerol-serine O-phosphatidyltransferase activity
What is CDP-diacylglycerol-serine O-phosphatidyltransferase activity?
It is the enzymatic activity (GO:0003882) that catalyzes the reaction of CDP-diacylglycerol with L-serine to form phosphatidylserine and CMP [1, 6].
What genes encode CDP-diacylglycerol-serine O-phosphatidyltransferase?
In humans, PTDSS1 and PTDSS2 encode phosphatidylserine synthases 1 and 2, respectively [1, 5]. In yeast, the gene is CHO1/PSS1, and in E. coli, it is pssA [2, 8].
What is the function of phosphatidylserine synthase?
It synthesizes phosphatidylserine, a key phospholipid for membrane structure and signaling, and provides precursors for phosphatidylethanolamine and phosphatidylcholine [2, 4].
How is CDP-diacylglycerol-serine O-phosphatidyltransferase activity regulated?
It is regulated by substrate availability (CDP-diacylglycerol), product inhibition, and in yeast by inositol and choline [2, 4]. Human PSS2 is regulated by SREBP.
What diseases are associated with mutations in PTDSS1?
Mutations in PTDSS1 cause Lenz-Majewski syndrome, a rare developmental disorder.
Can inhibition of PSS1 lower cholesterol?
Yes, inhibition of PSS1 promotes LDL uptake in cells, suggesting a potential strategy for lowering cholesterol.
What is the catalytic mechanism of phosphatidylserine synthase?
It proceeds via a phosphatidyl-enzyme intermediate, with a conserved histidine as the nucleophile [6, 8].
How can I study CDP-diacylglycerol-serine O-phosphatidyltransferase activity in the lab?
Common methods include in vitro enzyme assays, lipidomics, CRISPR knockout/knock-in, and structural biology [1, 6, 8].
Is phosphatidylserine synthase a drug target?
Yes, it is considered a target for dyslipidemia and potentially for antifungal and antibacterial therapies [1, 7, 8].
What model organisms are used to study this activity?
E. coli, S. cerevisiae, C. albicans, and human cell lines are commonly used [2, 4, 7, 8].
Conclusion
CDP-diacylglycerol-serine O-phosphatidyltransferase activity (GO:0003882) is a fundamental enzymatic activity in phospholipid metabolism, with critical roles in membrane biogenesis, lipid signaling, and human disease. Structural and biochemical studies have elucidated its catalytic mechanism, and genetic models have revealed its importance in cholesterol homeostasis and metabolic regulation. Targeting this activity holds promise for therapeutic intervention in dyslipidemia and other disorders. EDITGENE provides comprehensive CRISPR services to facilitate research on this important enzyme.
References
- 1. Long T et al.. 2024. Molecular insights into human phosphatidylserine synthase 1 reveal its inhibition promotes LDL uptake.. Cell 187(20):5665-5678.e18 PMID: 39208797
- 2. Carman GM et al.. 2018. Phosphatidate phosphatase regulates membrane phospholipid synthesis via phosphatidylserine synthase.. Adv Biol Regul 67:49-58 PMID: 28827025
- 3. Morii H et al.. 2003. CDP-2,3-Di-O-geranylgeranyl-sn-glycerol:L-serine O-archaetidyltransferase (archaetidylserine synthase) in the methanogenic archaeon Methanothermobacter thermautotrophicus.. J Bacteriol 185(4):1181-9 PMID: 12562787
- 4. Yamashita S et al.. 1997. Phosphatidylserine synthase from yeast.. Biochim Biophys Acta 1348(1-2):228-35 PMID: 9370337
- 5. Li D et al.. 2025. Molecular insights into human phosphatidylserine synthase 2 and its regulation of SREBP pathways.. Proc Natl Acad Sci U S A 122(20):e2501177122 PMID: 40372437
- 6. Centola M et al.. 2021. Crystal structures of phosphatidyl serine synthase PSS reveal the catalytic mechanism of CDP-DAG alcohol O-phosphatidyl transferases.. Nat Commun 12(1):6982 PMID: 34848707
- 7. Zhou Y et al.. 2021. Mapping the Substrate-Binding Sites in the Phosphatidylserine Synthase in Candida albicans.. Front Cell Infect Microbiol 11:765266 PMID: 35004345
- 8. Lee E et al.. 2024. Structural basis for membrane association and catalysis by phosphatidylserine synthase in Escherichia coli.. Sci Adv 10(51):eadq4624 PMID: 39693441
