GO:0004609 phosphatidylserine decarboxylase activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0004609 phosphatidylserine decarboxylase activity catalyzes the conversion of phosphatidyl-L-serine to phosphatidylethanolamine with release of CO2.
• The reaction is a key source of phosphatidylethanolamine, a major mitochondrial and membrane phospholipid, and supports mitochondrial bioenergetics and autophagy.
• In yeast, two distinct enzymes carry this activity: the mitochondrial PSD1 and the non-mitochondrial PSD2.
• Loss or inhibition of phosphatidylserine decarboxylase activity impairs mitochondrial function and can trigger apoptosis in hepatic cells.
• The enzyme is a target for antifungal development, as doxorubicin inhibits fungal phosphatidylserine decarboxylase.
• Accurate measurement of phosphatidylserine decarboxylase activity is enabled by selective fluorescence assays.
Description
Phosphatidylserine decarboxylase activity (GO:0004609) is a molecular function that catalyzes the decarboxylation of phosphatidyl-L-serine to produce phosphatidylethanolamine and carbon dioxide. This reaction is a principal route for phosphatidylethanolamine synthesis in mitochondria and is essential for maintaining membrane lipid homeostasis. The activity is conserved from yeast to humans and is encoded by distinct genes that localize to different cellular compartments. Researchers study this activity because it influences mitochondrial bioenergetics, autophagosome formation, and cell survival. In yeast, the mitochondrial enzyme PSD1 and a non-mitochondrial PSD2 both exhibit phosphatidylserine decarboxylase activity, with PSD2 contributing to phospholipid N-methylation pathways. In mammalian cells, reduced phosphatidylserine decarboxylase activity is linked to mitochondrial dysfunction and apoptosis in models of uric acid-induced hepatic injury. The enzyme is also a potential antifungal target, as doxorubicin inhibits its activity and confers broad-spectrum antifungal effects. Given its central role in lipid metabolism, precise measurement and manipulation of phosphatidylserine decarboxylase activity are critical for understanding metabolic and neurodegenerative diseases.
phosphatidylserine decarboxylase activity At A Glance
| GO ID | GO:0004609 |
|---|---|
| GO term | phosphatidylserine decarboxylase activity |
| Ontology | molecular_function |
| Synonym | phosphatidyl-L-serine carboxy-lyase activity; phosphatidyl-L-serine carboxy-lyase (phosphatidylethanolamine-forming); PS decarboxylase activity |
| Major function | Catalyzes the conversion of phosphatidyl-L-serine to phosphatidylethanolamine and CO2 |
| Reaction | H+ + phosphatidyl-L-serine = CO2 + phosphatidylethanolamine |
| Cellular context | Mitochondrial and non-mitochondrial forms exist in yeast |
| Physiological role | Supports mitochondrial bioenergetics and autophagosome formation |
| Disease relevance | Linked to hepatic mitochondrial dysfunction and apoptosis |
What Is GO:0004609?
Phosphatidylserine decarboxylase activity (GO:0004609) is defined as the catalysis of the reaction: H+ + phosphatidyl-L-serine = CO2 + phosphatidylethanolamine. In other words, it removes a carboxyl group from phosphatidylserine, converting it into phosphatidylethanolamine, a major membrane phospholipid. This activity is a molecular function that can be carried out by different enzymes in different cellular locations, such as mitochondrial and non-mitochondrial forms in yeast.
Why Is phosphatidylserine decarboxylase activity Important in Cell Biology?
Phosphatidylserine decarboxylase activity is essential for phospholipid homeostasis and mitochondrial function, making it a critical node in cellular metabolism. Its product, phosphatidylethanolamine, is required for autophagosome formation and mitochondrial bioenergetics, and its loss impairs these processes. In yeast, the coordinate regulation of this activity with phospholipid N-methylation highlights its role in membrane lipid remodeling. In humans, decreased phosphatidylserine decarboxylase activity contributes to uric acid-induced hepatic mitochondrial dysfunction and apoptosis, suggesting a role in metabolic liver diseases. The enzyme is also a validated antifungal target, as its inhibition by doxorubicin disrupts fungal membrane integrity. Therefore, understanding and measuring this activity is vital for both basic cell biology and therapeutic development.
• Provides a major source of phosphatidylethanolamine, a key membrane phospholipid.
• Supports mitochondrial bioenergetics and ATP production.
• Required for autophagosome formation and autophagic flux.
• Its downregulation is linked to hepatic mitochondrial dysfunction and apoptosis.
• Serves as a target for antifungal drugs like doxorubicin.
• Regulated in coordination with phospholipid N-methylation in yeast.
• Distinct mitochondrial and non-mitochondrial isoforms exist in yeast.
• Activity can be measured with selective fluorescence assays.
• Implicated in age-associated reduction of ER-mitochondrial contacts in the heart.
• Potential role in tauopathy via mitochondrial bioenergetics and autophagy.
Molecular Mechanism of phosphatidylserine decarboxylase activity
Substrate recognition and binding
In simple terms: The enzyme grabs phosphatidylserine from the membrane.
Phosphatidylserine decarboxylase activity requires the substrate phosphatidyl-L-serine, which is typically presented in a membrane environment. The enzyme binds the phosphatidylserine headgroup and positions it for decarboxylation. In yeast, both mitochondrial and non-mitochondrial enzymes can recognize phosphatidylserine, but they differ in their membrane localization and regulation.
Catalytic decarboxylation
In simple terms: The enzyme removes a carboxyl group, releasing CO2 and forming phosphatidylethanolamine.
The catalytic step involves the decarboxylation of phosphatidyl-L-serine to yield phosphatidylethanolamine and carbon dioxide. This reaction is a pyridoxal phosphate-independent decarboxylation that likely involves a pyruvoyl cofactor in some enzymes, but the exact mechanism may vary; the overall stoichiometry is well established. The activity is essential for maintaining phosphatidylethanolamine levels in mitochondria.
Product release and membrane integration
In simple terms: The newly made phosphatidylethanolamine is released into the membrane.
After decarboxylation, phosphatidylethanolamine is released into the lipid bilayer, where it contributes to membrane structure and function. This product is critical for mitochondrial membrane integrity and serves as a precursor for other phospholipids. In yeast, the non-mitochondrial PSD2 enzyme contributes to phosphatidylethanolamine pools that can be further methylated.
Regulation by cellular signals
In simple terms: The activity is turned up or down by cellular conditions.
Phosphatidylserine decarboxylase activity is regulated in coordination with phospholipid N-methylation in yeast, ensuring balanced phospholipid synthesis. In mammalian cells, mitochondrial bioenergetic status can influence the demand for phosphatidylethanolamine, indirectly affecting the activity. Age-associated reduction in ER-mitochondrial contacts impairs mitochondrial lipid metabolism, including phosphatidylethanolamine synthesis, in the heart.
Inhibition and pharmacological targeting
In simple terms: Certain drugs can block the enzyme, which can kill fungi.
Doxorubicin inhibits phosphatidylserine decarboxylase activity and confers broad-spectrum antifungal activity, demonstrating that the enzyme is a druggable target. This inhibition disrupts fungal membrane phospholipid composition, leading to growth arrest. Selective fluorescence assays have been developed to measure such inhibition accurately.
Key Genes Involved in GO:0004609 phosphatidylserine decarboxylase activity
The following genes encode enzymes or related proteins that carry or regulate phosphatidylserine decarboxylase activity across species.
| Gene | Major Role | Research Relevance |
|---|---|---|
| PSD1 (yeast) | Mitochondrial phosphatidylserine decarboxylase | Primary enzyme for mitochondrial phosphatidylethanolamine synthesis |
| PSD2 (yeast) | Non-mitochondrial phosphatidylserine decarboxylase | Contributes to phospholipid N-methylation and membrane homeostasis |
| PISD (human) | Mitochondrial phosphatidylserine decarboxylase | Ortholog of yeast PSD1; linked to mitochondrial function |
| CHO1 (yeast) | Phosphatidylserine synthase | Provides substrate for PSD1/PSD2 |
| OPI3 (yeast) | Phospholipid N-methyltransferase | Coordinates with PSD activity in phospholipid methylation |
| PEM1/CHO2 (yeast) | Phosphatidylethanolamine N-methyltransferase | Works downstream of PSD in phosphatidylcholine synthesis |
| MAPT (human) | Tau protein | Mitochondrial bioenergetics and autophagy linked to PSD activity in tauopathy |
| PYURF (human) | Protein involved in pyrimidine metabolism | May influence mitochondrial metabolism but not directly PSD |
| PDHA1 (human) | Pyruvate dehydrogenase | Sedentary behavior suppresses pyruvate metabolism, indirectly affecting lipid metabolism |
| CPT1B (human) | Carnitine palmitoyltransferase 1B | Fatty acid oxidation, related to metabolic inflexibility |
| MFN2 (human) | Mitofusin 2 | ER-mitochondrial tethering; age-related loss impairs lipid metabolism |
| ATG5 (human) | Autophagy-related 5 | Autophagosome formation requires phosphatidylethanolamine |
| ATG7 (human) | Autophagy-related 7 | Autophagosome formation requires phosphatidylethanolamine |
| LC3B (human) | Microtubule-associated protein 1 light chain 3 beta | Lipidated by phosphatidylethanolamine during autophagy |
| BECN1 (human) | Beclin 1 | Autophagy initiation, linked to mitochondrial bioenergetics |
| SQSTM1 (human) | Sequestosome 1 | Autophagic cargo receptor, affected by PSD activity |
| UQCRC2 (human) | Ubiquinol-cytochrome c reductase core protein 2 | Mitochondrial respiratory chain component, affected by PSD downregulation |
How Is phosphatidylserine decarboxylase activity Regulated?
Phosphatidylserine decarboxylase activity is regulated at multiple levels. In yeast, its activity is coordinately regulated with phospholipid N-methylation, ensuring balanced synthesis of phosphatidylethanolamine and phosphatidylcholine. The presence of two distinct enzymes, mitochondrial PSD1 and non-mitochondrial PSD2, allows compartment-specific regulation. In mammalian cells, mitochondrial bioenergetic status influences the demand for phosphatidylethanolamine, and conditions that impair mitochondrial function, such as uric acid overload, downregulate phosphatidylserine decarboxylase activity. Age-associated reduction in ER-mitochondrial contacts also impairs mitochondrial lipid metabolism, including phosphatidylethanolamine synthesis, in the heart. Additionally, the activity can be inhibited pharmacologically by doxorubicin, which binds to the enzyme and blocks its catalytic function.
phosphatidylserine decarboxylase activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| PISD | Hepatic mitochondrial dysfunction and apoptosis | Uric acid-treated hepatocytes with PISD knockdown |
| MAPT | Tauopathy and neurodegeneration | Tauopathy neurons with PISD modulation |
| MFN2 | Cardiac aging and metabolic inflexibility | Aged mouse heart with MFN2 overexpression |
| PSD1/PSD2 | Fungal infections | Fungal strains treated with doxorubicin |
| PISD | Metabolic inflexibility in skeletal muscle | Sedentary mouse model with PISD manipulation |
Hepatic mitochondrial dysfunction and apoptosis
Downregulation of phosphatidylserine decarboxylase activity in uric acid-induced hepatic mitochondrial dysfunction leads to impaired mitochondrial respiration and increased apoptosis. This suggests that loss of this activity contributes to metabolic liver diseases characterized by mitochondrial damage.
Tauopathy and neurodegeneration
Mitochondrial bioenergetics stimulates autophagy for pathological MAPT/Tau clearance in tauopathy neurons, and phosphatidylethanolamine produced by phosphatidylserine decarboxylase activity is required for autophagosome formation. Thus, reduced activity may exacerbate Tau accumulation and neurodegeneration.
Cardiac aging and metabolic inflexibility
Age-associated reduction in ER-mitochondrial contacts impairs mitochondrial lipid metabolism and autophagosome formation in the heart, processes that depend on phosphatidylethanolamine generated by phosphatidylserine decarboxylase activity. This links the activity to cardiac aging and metabolic dysfunction.
Fungal infections
Doxorubicin inhibits phosphatidylserine decarboxylase and confers broad-spectrum antifungal activity, highlighting the enzyme as a target for antifungal drug development. Inhibition disrupts fungal membrane phospholipid composition, leading to cell death.
From phosphatidylserine decarboxylase activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of PISD impair mitochondrial respiration? | PISD knockout cell line (e.g., HEK293) |
| Does a point mutation in the catalytic site abolish enzyme activity? | PISD point-mutant knock-in via CRISPR |
| Can tagged PISD rescue phosphatidylethanolamine synthesis? | Knock-in of FLAG-tagged PISD |
| Does PISD overexpression protect against Tau aggregation? | PISD overexpression in tauopathy neurons |
| Does PSD2 compensate for PSD1 loss in yeast? | Yeast PSD1/PSD2 double knockout |
| Can doxorubicin-resistant mutants be generated? | CRISPR knockout library screening in fungi |
How to Study the phosphatidylserine decarboxylase activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Fluorescence assay | Enzymatic conversion of phosphatidylserine to phosphatidylethanolamine | Inhibitor screening and kinetic studies |
| CRISPR knockout | Loss of gene function | Assessing PISD requirement for mitochondrial function |
| Lipidomics (LC-MS) | Phosphatidylethanolamine and phosphatidylserine levels | Quantifying lipid changes in tissues |
| LC3B immunoblot | Autophagosome formation | Evaluating autophagy flux |
| Seahorse assay | Mitochondrial respiration | Measuring bioenergetics after PSD modulation |
| qRT-PCR | mRNA expression of PISD | Validating knockdown or overexpression |
| Immunofluorescence | Subcellular localization of PISD | Confirming mitochondrial targeting |
| Yeast complementation | Functional rescue by PSD genes | Testing ortholog function |
Fluorescence-based activity assays
A highly selective fluorescence assay has been developed to measure phosphatidylserine decarboxylase activity in cell lysates and purified fractions. This method uses a fluorescent phosphatidylserine analog and detects the decarboxylated product, allowing kinetic analysis and inhibitor screening.
Genetic knockout and knockdown
CRISPR-Cas9 knockout of PISD or yeast PSD1/PSD2 enables loss-of-function studies to assess the impact on mitochondrial function and autophagy. Knockdown using siRNA or shRNA provides a complementary approach for transient depletion.
Lipidomics and mass spectrometry
Mass spectrometry-based lipidomics can quantify phosphatidylethanolamine and phosphatidylserine levels to infer phosphatidylserine decarboxylase activity in cells and tissues. This approach is useful for assessing changes in lipid metabolism under different physiological conditions.
Autophagy flux analysis
Because phosphatidylethanolamine is required for LC3 lipidation, autophagy flux can be monitored by LC3B immunoblotting or fluorescence microscopy in cells with modulated phosphatidylserine decarboxylase activity. This links the activity to autophagosome formation.
How CRISPR Can Be Used to Study GO:0004609 phosphatidylserine decarboxylase activity
Knockout
CRISPR-Cas9 knockout of PISD in human cell lines abolishes phosphatidylserine decarboxylase activity, leading to reduced phosphatidylethanolamine levels and impaired mitochondrial respiration. Such models are valuable for studying the role of the enzyme in hepatic mitochondrial dysfunction and apoptosis.
Point Mutation
Introducing point mutations in the catalytic domain of PISD via CRISPR base editing or homology-directed repair can help identify residues essential for decarboxylation. These mutants allow precise structure-function analysis without complete loss of protein.
Knock-in
Knock-in of epitope-tagged PISD (e.g., FLAG or GFP) enables visualization and immunoprecipitation of the enzyme to study its localization and interactions. Tagged knock-in models are useful for tracking phosphatidylethanolamine synthesis in live cells.
Overexpression
CRISPR activation or lentiviral overexpression of PISD can increase phosphatidylserine decarboxylase activity, which may protect against Tau aggregation by enhancing autophagy. Overexpression models are also used to test whether increased phosphatidylethanolamine synthesis improves mitochondrial function.
How EDITGENE Supports phosphatidylserine decarboxylase activity Research
Researchers studying phosphatidylserine decarboxylase activity-related genes often need to determine whether a candidate gene is causally involved in lipid metabolism, mitochondrial function, or disease. EDITGENE provides custom CRISPR cell models to interrogate gene function with precision and reproducibility.
Contact EDITGENE today to design your custom CRISPR model for phosphatidylserine decarboxylase activity research.
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| GOT1 Knockout HEK293 Cell Line | EDJ-KQ4751 | Human | 2805 | Details Get a Quote |
| GOT1 Knockout HCT 116 Cell Line | EDJ-KQ26273 | Human | 2805 | Details Get a Quote |
| GOT1 Knockout A-549 Cell Line | EDJ-KQ27508 | Human | 2805 | Details Get a Quote |
| GOT1 Knockout HeLa Cell Line | EDJ-KQ27510 | Human | 2805 | Details Get a Quote |
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Frequently Asked Questions About phosphatidylserine decarboxylase activity
What is phosphatidylserine decarboxylase activity?
It is the enzymatic activity (GO:0004609) that converts phosphatidyl-L-serine to phosphatidylethanolamine and carbon dioxide.
What genes encode phosphatidylserine decarboxylase?
In yeast, PSD1 and PSD2 encode mitochondrial and non-mitochondrial enzymes, respectively; in humans, PISD is the ortholog.
What is the reaction catalyzed by phosphatidylserine decarboxylase?
H+ + phosphatidyl-L-serine = CO2 + phosphatidylethanolamine.
Why is phosphatidylserine decarboxylase important for mitochondria?
It produces phosphatidylethanolamine, a key mitochondrial membrane lipid required for bioenergetics and autophagy.
How is phosphatidylserine decarboxylase activity measured?
Selective fluorescence assays using phosphatidylserine analogs are commonly used.
What diseases are linked to phosphatidylserine decarboxylase dysfunction?
Hepatic mitochondrial dysfunction, tauopathy, and cardiac aging have been associated with altered activity.
Can phosphatidylserine decarboxylase be targeted for antifungal therapy?
Yes, doxorubicin inhibits the enzyme and shows broad-spectrum antifungal activity.
What is the difference between PSD1 and PSD2?
PSD1 is mitochondrial, while PSD2 is non-mitochondrial and contributes to phospholipid N-methylation in yeast.
How does phosphatidylserine decarboxylase relate to autophagy?
Phosphatidylethanolamine produced by the enzyme is required for LC3 lipidation and autophagosome formation.
What CRISPR models are available for studying phosphatidylserine decarboxylase?
Knockout, point mutation, knock-in, and overexpression models can be custom-generated by EDITGENE.
Conclusion
Phosphatidylserine decarboxylase activity (GO:0004609) is a fundamental enzymatic function that supplies phosphatidylethanolamine for mitochondrial membranes and autophagosomes. Its dysregulation is implicated in hepatic injury, neurodegeneration, and cardiac aging, and it is a promising antifungal target. Advances in fluorescence assays and CRISPR models now enable precise interrogation of this activity in health and disease. Continued research will clarify its therapeutic potential across metabolic and neurodegenerative disorders.
References
- 1. Zhou Y et al.. 2023. Doxorubicin inhibits phosphatidylserine decarboxylase and confers broad-spectrum antifungal activity.. New Phytol 239(1):255-270 PMID: 37148193
- 2. Jia N et al.. 2025. Mitochondrial bioenergetics stimulates autophagy for pathological MAPT/Tau clearance in tauopathy neurons.. Autophagy 21(1):54-79 PMID: 39171695
- 3. Hong W et al.. 2025. Age-associated reduction in ER-Mitochondrial contacts impairs mitochondrial lipid metabolism and autophagosome formation in the heart.. Cell Death Differ 32(10):1900-1914 PMID: 40254645
- 4. Carson MA et al.. 1984. Coordinate regulation of phosphatidylserine decarboxylase activity and phospholipid N-methylation in yeast.. J Biol Chem 259(10):6267-73 PMID: 6427211
- 5. Choi JY et al.. 2020. An improved and highly selective fluorescence assay for measuring phosphatidylserine decarboxylase activity.. J Biol Chem 295(27):9211-9222 PMID: 32430397
- 6. Siripoksup P et al.. 2024. Sedentary behavior in mice induces metabolic inflexibility by suppressing skeletal muscle pyruvate metabolism.. J Clin Invest 134(11) PMID: 38652544
- 7. Trotter PJ et al.. 1995. Identification of a non-mitochondrial phosphatidylserine decarboxylase activity (PSD2) in the yeast Saccharomyces cerevisiae.. J Biol Chem 270(11):6062-70 PMID: 7890739
- 8. Liu N et al.. 2023. Phosphatidylserine decarboxylase downregulation in uric acid‑induced hepatic mitochondrial dysfunction and apoptosis.. MedComm (2020) 4(4):e336 PMID: 37502610
