GO:0047191 1-alkylglycerophosphocholine O-acyltransferase activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0047191 describes the enzymatic activity that transfers an acyl group from acyl-CoA to 1-alkyl-sn-glycero-3-phosphocholine, producing 1-alkyl-2-acyl-sn-glycero-3-phosphocholine and CoA.
• This activity is a key step in the remodeling pathway for platelet-activating factor (PAF) biosynthesis, converting the immediate PAF precursor lyso-PAF into PAF.
• The enzyme responsible is often referred to as lysophosphatidylcholine acyltransferase 2 (LPCAT2), which exhibits 1-alkylglycerophosphocholine O-acyltransferase activity.
• Selective inhibitors of LPCAT2 have been developed, providing chemical tools to probe PAF biosynthesis and this enzymatic activity.
• Dysregulation of this activity may contribute to inflammatory diseases, cancer, and cardiovascular disorders through altered PAF and related phospholipid levels.
• CRISPR-based knockout, knock-in, and overexpression models enable precise interrogation of this activity in cell and animal systems.
Description
1-alkylglycerophosphocholine O-acyltransferase activity (GO:0047191) is a molecular function defined by the catalytic transfer of an acyl group from acyl-CoA to 1-alkyl-sn-glycero-3-phosphocholine, yielding 1-alkyl-2-acyl-sn-glycero-3-phosphocholine and CoA. This reaction is a critical enzymatic step in the remodeling pathway of platelet-activating factor (PAF) biosynthesis, where it converts the inactive precursor lyso-PAF into the potent lipid mediator PAF. The activity is attributed to specific lysophospholipid acyltransferases, notably LPCAT2, which was identified as a PAF biosynthetic enzyme. Researchers study GO:0047191 to understand inflammatory signaling, phospholipid remodeling, and the molecular basis of diseases linked to PAF dysregulation. The availability of selective inhibitors for LPCAT2 further underscores the importance of this activity as a druggable target.
1-alkylglycerophosphocholine O-acyltransferase activity At A Glance
| GO ID | GO:0047191 |
|---|---|
| GO term | 1-alkylglycerophosphocholine O-acyltransferase activity |
| Ontology | molecular_function |
| Synonym | acyl-CoA:1-alkyl-sn-glycero-3-phosphocholine O-acyltransferase activity |
| Definition | Catalysis of the reaction: 1-alkyl-sn-glycero-3-phosphocholine + acyl-CoA = 1-alkyl-2-acyl-sn-glycero-3-phosphocholine + CoA. |
| Major function | Acyl transfer in phospholipid remodeling and PAF biosynthesis |
| EC number | Not assigned in QuickGO |
| Related enzyme | LPCAT2 (lysophosphatidylcholine acyltransferase 2) |
What Is GO:0047191?
According to the Gene Ontology, GO:0047191 is defined as the catalysis of the reaction: 1-alkyl-sn-glycero-3-phosphocholine + acyl-CoA = 1-alkyl-2-acyl-sn-glycero-3-phosphocholine + CoA. In other words, it is an O-acyltransferase activity that adds an acyl chain to the sn-2 position of a 1-alkyl lysophospholipid, using acyl-CoA as the acyl donor. This activity is synonymous with acyl-CoA:1-alkyl-sn-glycero-3-phosphocholine O-acyltransferase activity.
Why Is 1-alkylglycerophosphocholine O-acyltransferase activity Important in Cell Biology?
GO:0047191 is important because it represents a committed step in the biosynthesis of platelet-activating factor (PAF), a potent pro-inflammatory phospholipid mediator. By converting lyso-PAF to PAF, this activity directly controls the availability of PAF for autocrine and paracrine signaling. Dysregulated PAF signaling has been implicated in a wide range of pathological conditions, including acute inflammation, allergy, atherosclerosis, and cancer. Therefore, understanding and targeting this enzymatic activity offers therapeutic potential for modulating inflammatory responses and related diseases.
• Critical for PAF biosynthesis via the remodeling pathway.
• Regulates levels of PAF, a key mediator of inflammation and anaphylaxis.
• Involved in phospholipid remodeling and membrane homeostasis.
• LPCAT2, the enzyme with this activity, is a potential drug target for inflammatory diseases.
• Selective inhibitors of LPCAT2 can modulate PAF production.
• May contribute to cancer progression through altered lipid signaling.
• Relevant to cardiovascular diseases linked to PAF.
• Provides a molecular handle for studying lipid mediator networks.
• Enables CRISPR-based functional genomics of lipid metabolism.
• Supports development of diagnostics and therapeutics targeting PAF pathway.
Molecular Mechanism of 1-alkylglycerophosphocholine O-acyltransferase activity
Substrate Recognition and Binding
In simple terms: The enzyme grabs the starting materials: a lyso-PAF molecule and an acyl-CoA.
The enzyme binds 1-alkyl-sn-glycero-3-phosphocholine (lyso-PAF) and acyl-CoA in its active site. The alkyl chain at the sn-1 position and the phosphocholine headgroup are recognized by specific residues, positioning the sn-2 hydroxyl for attack.
Catalytic Acyl Transfer
In simple terms: The enzyme moves the acyl chain from acyl-CoA onto lyso-PAF.
A conserved catalytic mechanism, likely involving a histidine or serine residue, facilitates the nucleophilic attack of the sn-2 hydroxyl on the thioester carbonyl of acyl-CoA. This results in the formation of an ester bond at the sn-2 position and release of CoA.
Product Release and Enzyme Turnover
In simple terms: The finished PAF molecule is released, and the enzyme is ready to work again.
After acyl transfer, the product 1-alkyl-2-acyl-sn-glycero-3-phosphocholine (PAF) is released from the active site, followed by CoA. The enzyme can then undergo another catalytic cycle. The reaction is reversible in vitro but favors PAF synthesis in vivo.
Regulation by Inhibitors and Cellular Signals
In simple terms: Other molecules can block or enhance the enzyme's activity.
Selective inhibitors of LPCAT2, such as those described by Tarui et al., can block this activity, reducing PAF production. Cellular signals that alter LPCAT2 expression or post-translational modifications may also regulate the activity.
Key Genes Involved in GO:0047191 1-alkylglycerophosphocholine O-acyltransferase activity
The following genes and proteins are directly or indirectly associated with 1-alkylglycerophosphocholine O-acyltransferase activity, based on published literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| LPCAT2 | Enzyme exhibiting 1-alkylglycerophosphocholine O-acyltransferase activity; PAF biosynthetic enzyme | Target for inhibitor development and CRISPR knockout studies |
| LPCAT1 | Related lysophospholipid acyltransferase with broader substrate specificity | Potential compensatory enzyme; comparative studies |
| PLA2G7 | Lipoprotein-associated phospholipase A2; produces lyso-PAF | Upstream of GO:0047191 in PAF remodeling pathway |
| PAFAH1B1 | PAF acetylhydrolase; degrades PAF | Regulates PAF levels; balance with GO:0047191 |
| CHKA | Choline kinase alpha; synthesizes phosphocholine | Provides substrate for phospholipid remodeling |
| PCYT1A | CTP:phosphocholine cytidylyltransferase; rate-limiting in phosphatidylcholine synthesis | Indirectly affects substrate availability |
| CEPT1 | Choline/ethanolamine phosphotransferase 1 | Contributes to phospholipid synthesis |
| LPCAT3 | Lysophosphatidylcholine acyltransferase 3 | Related family member with distinct substrate specificity |
| LPCAT4 | Lysophosphatidylcholine acyltransferase 4 | Related family member |
| AGPAT1 | 1-acylglycerol-3-phosphate O-acyltransferase 1 | Similar acyltransferase activity but different substrate |
| AGPAT2 | 1-acylglycerol-3-phosphate O-acyltransferase 2 | Similar acyltransferase activity |
| GPAT1 | Glycerol-3-phosphate acyltransferase 1 | Involved in glycerophospholipid synthesis |
| MBOAT1 | Membrane-bound O-acyltransferase 1 | Potential acyltransferase with related function |
| MBOAT2 | Membrane-bound O-acyltransferase 2 | Potential acyltransferase |
| PLA2G4A | Cytosolic phospholipase A2; releases arachidonic acid | Cross-talk with PAF pathway |
| PTGS2 | Cyclooxygenase-2; inflammatory mediator | Co-regulated with PAF in inflammation |
| ALOX5 | 5-lipoxygenase; leukotriene synthesis | Inflammatory lipid mediator pathway |
| NFKB1 | Nuclear factor kappa B subunit 1; transcription factor | Regulates expression of inflammatory genes including LPCAT2 |
How Is 1-alkylglycerophosphocholine O-acyltransferase activity Regulated?
The activity of 1-alkylglycerophosphocholine O-acyltransferase is primarily regulated at the level of enzyme expression and post-translational modification. Inflammatory stimuli can induce LPCAT2 expression through NF-kB signaling, increasing PAF production. Additionally, the activity can be inhibited by selective small molecules, such as those identified by Tarui et al., which block the enzyme's catalytic function. Cellular levels of substrates (lyso-PAF and acyl-CoA) also influence the reaction rate.
1-alkylglycerophosphocholine O-acyltransferase activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| LPCAT2 | Inflammation, allergy, cancer | LPCAT2 knockout mice; cell lines with CRISPR KO |
| PLA2G7 | Cardiovascular disease | PLA2G7 transgenic mice |
| PAFAH1B1 | Neurodevelopmental disorders | PAFAH1B1 knockout models |
| NFKB1 | Inflammatory diseases | NFKB1 reporter cell lines |
| PTGS2 | Cancer, inflammation | PTGS2 overexpression models |
Inflammation and Allergy
PAF is a potent mediator of inflammation and anaphylaxis. Excessive 1-alkylglycerophosphocholine O-acyltransferase activity, by increasing PAF synthesis, contributes to inflammatory diseases such as asthma, arthritis, and sepsis. Inhibiting this activity may reduce PAF levels and alleviate symptoms.
Cancer
Altered phospholipid metabolism is a hallmark of cancer. LPCAT2, the enzyme with this activity, has been implicated in tumor progression and metastasis in some cancers, possibly through PAF-mediated signaling. Targeting this activity could be a therapeutic strategy.
Cardiovascular Disease
PAF contributes to atherosclerosis, thrombosis, and vascular inflammation. Dysregulated 1-alkylglycerophosphocholine O-acyltransferase activity may promote cardiovascular pathology by increasing PAF production. Modulating this activity is of interest for cardiovascular drug development.
From 1-alkylglycerophosphocholine O-acyltransferase activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does LPCAT2 knockout reduce PAF production? | LPCAT2 KO cell line via CRISPR |
| Can a point mutation in LPCAT2 abolish enzymatic activity? | LPCAT2 point-mutant knock-in cells |
| Does overexpression of LPCAT2 increase PAF levels? | LPCAT2 overexpression cell line |
| Where is LPCAT2 localized in the cell? | LPCAT2 tagged knock-in with fluorescent tag |
| What genes interact with LPCAT2? | CRISPR library screening |
| Does LPCAT2 inhibition affect inflammation in vivo? | LPCAT2 KO mouse model |
How to Study the 1-alkylglycerophosphocholine O-acyltransferase activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Radioenzymatic assay | Enzyme activity using radiolabeled acyl-CoA | Kinetic studies of LPCAT2 |
| LC-MS/MS lipidomics | PAF and phospholipid species | Profiling in cells/tissues |
| CRISPR KO | Loss of enzyme function | Validation of LPCAT2 as PAF synthase |
| CRISPR knock-in | Mutant or tagged enzyme expression | Structure-function studies |
| Western blot | Protein expression levels | Assessing LPCAT2 regulation |
| qRT-PCR | mRNA expression | Transcriptional regulation |
| Inhibitor screening | Enzyme inhibition | Drug discovery |
| Immunofluorescence | Subcellular localization | Organelle targeting |
Enzymatic Activity Assays
In vitro assays using radiolabeled or fluorescent substrates can directly measure 1-alkylglycerophosphocholine O-acyltransferase activity. Typically, lyso-PAF and acyl-CoA are incubated with cell lysates or purified enzyme, and the formation of PAF is quantified by thin-layer chromatography or mass spectrometry.
Lipidomics and Mass Spectrometry
Mass spectrometry-based lipidomics enables comprehensive profiling of phospholipids, including PAF and its precursors, in cells or tissues. This method can assess changes in the activity of GO:0047191 indirectly by measuring product levels.
CRISPR-Cas9 Knockout and Knock-in
CRISPR-Cas9 can generate LPCAT2 knockout cells to study loss of activity, or knock-in cells expressing mutant or tagged LPCAT2 to dissect domain functions and localization.
Inhibitor Studies
Selective inhibitors of LPCAT2, such as those described by Tarui et al., can be used in cell-based assays to acutely block the activity and assess downstream effects on PAF signaling.
How CRISPR Can Be Used to Study GO:0047191 1-alkylglycerophosphocholine O-acyltransferase activity
Knockout
CRISPR-Cas9 knockout of LPCAT2 eliminates 1-alkylglycerophosphocholine O-acyltransferase activity, allowing researchers to study its role in PAF biosynthesis and inflammation. Knockout cell lines can be used to confirm that LPCAT2 is the primary enzyme responsible for this activity in a given cell type.
Point Mutation
Introducing point mutations in the catalytic residues of LPCAT2 via CRISPR can abolish enzymatic activity without affecting protein expression, providing a clean way to separate catalytic function from scaffolding roles.
Knock-in
Knock-in of a tagged or fluorescently labeled LPCAT2 allows real-time tracking of the enzyme's localization and dynamics. This can reveal where the activity occurs within the cell, such as the endoplasmic reticulum or lipid droplets.
Overexpression
CRISPR activation or lentiviral overexpression of LPCAT2 increases 1-alkylglycerophosphocholine O-acyltransferase activity, leading to elevated PAF production. This model is useful for studying the consequences of excess PAF signaling in inflammation and cancer.
How EDITGENE Supports 1-alkylglycerophosphocholine O-acyltransferase activity Research
Researchers studying 1-alkylglycerophosphocholine O-acyltransferase activity-related genes often need to determine whether a candidate gene is causally involved in PAF biosynthesis, inflammatory signaling, or phospholipid remodeling. EDITGENE provides a comprehensive suite of CRISPR-based services to accelerate this research.
Contact EDITGENE today to design your custom CRISPR model for 1-alkylglycerophosphocholine O-acyltransferase activity research.
Frequently Asked Questions About 1-alkylglycerophosphocholine O-acyltransferase activity
What is 1-alkylglycerophosphocholine O-acyltransferase activity?
It is an enzymatic activity (GO:0047191) that transfers an acyl group from acyl-CoA to lyso-PAF, producing PAF and CoA, as defined by the Gene Ontology.
What genes are involved in 1-alkylglycerophosphocholine O-acyltransferase activity?
The primary gene is LPCAT2, which encodes an enzyme with this activity. Related genes include LPCAT1, LPCAT3, and LPCAT4.
What is the role of GO:0047191 in PAF biosynthesis?
GO:0047191 catalyzes the final step in the remodeling pathway of PAF biosynthesis, converting lyso-PAF to PAF.
Which diseases are associated with 1-alkylglycerophosphocholine O-acyltransferase activity?
It has been linked to inflammatory diseases, allergy, cancer, and cardiovascular disorders due to its role in PAF production.
How can I measure 1-alkylglycerophosphocholine O-acyltransferase activity?
Activity can be measured using radioenzymatic assays with radiolabeled acyl-CoA, or by quantifying PAF production via mass spectrometry.
Are there inhibitors of 1-alkylglycerophosphocholine O-acyltransferase activity?
Yes, selective inhibitors of LPCAT2 have been developed and can block this activity.
What is the relationship between LPCAT2 and GO:0047191?
LPCAT2 is the enzyme that exhibits 1-alkylglycerophosphocholine O-acyltransferase activity, as demonstrated in biochemical studies.
Can CRISPR be used to study 1-alkylglycerophosphocholine O-acyltransferase activity?
Yes, CRISPR knockout, knock-in, and overexpression models allow precise manipulation of LPCAT2 to study its function.
What are the substrates of 1-alkylglycerophosphocholine O-acyltransferase?
The substrates are 1-alkyl-sn-glycero-3-phosphocholine (lyso-PAF) and acyl-CoA.
What is the product of the reaction catalyzed by GO:0047191?
The products are 1-alkyl-2-acyl-sn-glycero-3-phosphocholine (PAF) and CoA.
Conclusion
1-alkylglycerophosphocholine O-acyltransferase activity (GO:0047191) is a key enzymatic function in PAF biosynthesis and phospholipid remodeling. Its primary enzyme, LPCAT2, has been implicated in inflammation, cancer, and cardiovascular disease, making it an attractive target for therapeutic intervention. Advances in CRISPR-based gene editing and lipidomics provide powerful tools to dissect the regulation and pathophysiological roles of this activity. EDITGENE offers comprehensive services to support researchers in this endeavor.
References
- 1. Shindou H. 2008. [Lysophospholipid acyltransferase and platelet-activating factor (PAF) biosynthetic enzyme].. Seikagaku 80(2):110-3 PMID: 18341030
- 2. Tarui M et al.. 2014. Selective inhibitors of a PAF biosynthetic enzyme lysophosphatidylcholine acyltransferase 2.. J Lipid Res 55(7):1386-96 PMID: 24850807
