GO:0140322 A1-type glycerophospholipase activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0140322 defines A1-type glycerophospholipase activity, a molecular function that cleaves the fatty acid at the sn-1 position of glycerophospholipids.
• This activity is distinct from A2-type phospholipases, which cleave at the sn-2 position, and is often assayed using specific substrates.
• A1-type glycerophospholipase activity has been linked to astrocyte activation states, particularly the A1 neuroinflammatory phenotype.
• Dysregulation of this activity is implicated in ischemic stroke, neuroinflammation, and sepsis-associated encephalopathy [1,2,6,7].
• Key genes associated with this activity include phospholipase A1 family members and downstream inflammatory mediators such as STAT3 and NLRP3 [4,8].
• CRISPR-based models (knockout, point mutation, knock-in, overexpression) are essential to dissect the causal role of A1-type glycerophospholipase activity in disease.
Description
A1-type glycerophospholipase activity (GO:0140322) is a molecular function that removes the fatty acid esterified at the sn-1 position of glycerophospholipids, generating a free fatty acid and a 2-acyl lysophospholipid. This activity is part of the broader phospholipase A1 family and is critical for membrane remodeling and lipid signaling. Unlike A2-type phospholipases, which act at the sn-2 position, A1-type activity has been less studied but is increasingly recognized for its role in neuroinflammation and cellular stress responses. Recent studies have linked A1-type glycerophospholipase activity to astrocyte reactivity, particularly the A1 neurotoxic phenotype, which is associated with ischemic stroke and other neurological disorders [1,5]. For example, inhibition of Lcn2 in astrocytes reduces ischemic stroke injury, suggesting that lipid-modifying enzymes contribute to neuroinflammatory cascades. Similarly, cottonseed oil alleviates ischemic stroke by inhibiting inflammatory activation of microglia and astrocytes, highlighting the therapeutic potential of targeting lipid pathways. Understanding the regulation and function of A1-type glycerophospholipase activity is therefore essential for developing novel interventions in neuroinflammatory diseases.
A1-type glycerophospholipase activity At A Glance
| GO ID | GO:0140322 |
|---|---|
| GO term | A1-type glycerophospholipase activity |
| Ontology | molecular_function |
| Synonym | None |
| Definition | A glycerophospholipase activity that cleaves the fatty acid attached to the sn-1 position of the glycerol group of a glycerophospholipid. |
| Major function | Hydrolysis of sn-1 fatty acyl ester bonds in glycerophospholipids |
| Related activity | A2-type glycerophospholipase activity (cleaves at sn-2 position) |
| Substrates | Glycerophospholipids such as phosphatidylcholine, phosphatidylethanolamine |
| Products | Free fatty acid and 2-acyl lysophospholipid |
What Is GO:0140322?
A1-type glycerophospholipase activity is defined as a glycerophospholipase activity that cleaves the fatty acid attached to the sn-1 position of the glycerol group of a glycerophospholipid. This enzymatic action produces a free fatty acid and a lysophospholipid with a free hydroxyl at the sn-1 position, which can serve as a signaling molecule or be further metabolized. The activity is classified under molecular_function in the Gene Ontology and is distinct from A2-type phospholipases, which cleave at the sn-2 position.
Why Is A1-type glycerophospholipase activity Important in Cell Biology?
A1-type glycerophospholipase activity is important because it regulates membrane lipid composition and generates lipid mediators that influence inflammation, cell survival, and signaling. Dysregulation of this activity has been implicated in neuroinflammatory conditions such as ischemic stroke, where astrocyte activation and inflammatory markers are elevated [1,5]. Targeting this activity may offer therapeutic strategies for stroke and other neurological disorders [2,6].
• Regulates membrane phospholipid remodeling and lipid signaling.
• Contributes to the generation of lysophospholipids, which are bioactive mediators.
• Linked to A1-type astrocyte activation, a neurotoxic phenotype.
• Implicated in ischemic stroke injury through inflammatory pathways [1,2].
• Associated with sepsis-associated encephalopathy via oxidative stress and ERK/NF-κB signaling.
• Potential role in chronic pain and neuroinflammation through STAT3 modulation.
• May influence gut-brain axis and cognitive function via NLRP3 inflammasome.
• Target for therapeutic intervention in neuroinflammatory diseases [1,6].
• Provides a mechanism for cross-talk between lipid metabolism and inflammation.
• Enables research into astrocyte heterogeneity and function.
What Happens During A1-type glycerophospholipase activity?
Substrate Recognition and Binding
In simple terms: The enzyme finds and binds to a phospholipid molecule in the membrane.
A1-type glycerophospholipase enzymes recognize glycerophospholipids within cellular membranes, often with specificity for the sn-1 acyl chain. Binding involves hydrophobic interactions with the lipid bilayer and a catalytic site that positions the sn-1 ester bond for hydrolysis. This step is critical for determining substrate specificity and is regulated by membrane composition and local lipid environment.
Catalytic Hydrolysis
In simple terms: The enzyme cuts the fatty acid off the first position of the glycerol backbone.
The catalytic mechanism typically involves a serine hydrolase triad (Ser-His-Asp) that activates a water molecule to attack the ester bond at the sn-1 position, releasing a free fatty acid and a 2-acyl lysophospholipid. This reaction is energy-independent and can occur in various cellular compartments.
Product Release and Signaling
In simple terms: The products are released and can act as signals or be further processed.
The released fatty acid and lysophospholipid can serve as signaling molecules or be metabolized by other enzymes. For example, lysophosphatidylcholine can activate inflammatory pathways, while free fatty acids can modulate ion channels and receptors. This step links A1-type glycerophospholipase activity to downstream cellular responses such as inflammation and apoptosis.
Regulation by Cellular Context
In simple terms: The activity is turned up or down depending on the cell's state.
A1-type glycerophospholipase activity is regulated by factors such as calcium ions, phosphorylation, and interaction with other proteins. In astrocytes, inflammatory stimuli can increase the expression of enzymes with this activity, contributing to the A1 neurotoxic phenotype. This regulation is crucial for adapting lipid metabolism to stress conditions.
Key Genes Involved in GO:0140322 A1-type glycerophospholipase activity
The following genes and proteins are associated with A1-type glycerophospholipase activity or its downstream effects, based on published literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| PLA1A | Phospholipase A1 member A, catalyzes sn-1 hydrolysis | Directly mediates A1-type glycerophospholipase activity |
| LCN2 | Lipocalin-2, regulates astrocyte phenotype | Inhibition reduces ischemic stroke injury via astrocyte modulation |
| STAT3 | Signal transducer and activator of transcription 3 | Modulates neuroinflammation and nociceptive sensitization |
| NLRP3 | NOD-like receptor family pyrin domain containing 3 | Inflammasome activation linked to cognitive function and gut microbiota |
| P2X7R | Purinergic receptor P2X7 | Induces A1-type astrocyte activation and inflammatory markers |
| TDP43 | TAR DNA-binding protein 43 | Augments astrocyte inflammatory activity via mtDNA-cGAS-STING axis |
| ERK | Extracellular signal-regulated kinase | Involved in oxidative stress and NF-κB signaling in encephalopathy |
| NF-κB | Nuclear factor kappa-light-chain-enhancer of activated B cells | Central to inflammatory gene expression in astrocytes |
| cGAS | Cyclic GMP-AMP synthase | Senses mtDNA and triggers STING-mediated inflammation |
| STING | Stimulator of interferon genes | Mediates inflammatory responses in astrocytes |
| APP | Amyloid precursor protein | Associated with Alzheimer's disease pathology and neuroinflammation |
| PS1 | Presenilin-1 | Component of gamma-secretase, linked to APP processing |
| Orexin-A | Neuropeptide regulating arousal and inflammation | Attenuates inflammatory response in sepsis-associated encephalopathy |
| Bt354 | STAT3 inhibitor | Ameliorates neuroinflammation in chronic constriction injury |
| Huanglian Jiedu Decoction | Traditional Chinese medicine formula | Improves cognitive function by inhibiting NLRP3 inflammasome |
| Cottonseed oil | Dietary oil rich in unsaturated fatty acids | Alleviates ischemic stroke by inhibiting microglial and astrocyte activation |
How Is A1-type glycerophospholipase activity Regulated?
A1-type glycerophospholipase activity is regulated at multiple levels, including gene expression, post-translational modifications, and interaction with regulatory proteins. Inflammatory stimuli such as P2X7 receptor activation can upregulate enzymes with this activity in astrocytes, contributing to the A1 neurotoxic phenotype. Additionally, signaling pathways such as ERK/NF-κB and STAT3 modulate the inflammatory response and may influence A1-type glycerophospholipase activity [7,8]. The gut microbiota and NLRP3 inflammasome also play a role in regulating neuroinflammation, potentially affecting lipid-modifying enzymes.
A1-type glycerophospholipase activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| LCN2 | Ischemic stroke | Knockout mice, astrocyte-specific overexpression |
| P2X7R | Neuroinflammation, A1 astrocyte activation | Point mutation, knockout |
| STAT3 | Chronic pain, neuroinflammation | Knock-in of inhibitor-resistant mutant, knockout |
| NLRP3 | Alzheimer's disease, cognitive impairment | Knockout, overexpression in APP/PS1 mice |
| TDP43 | NMOSD, astrocyte inflammation | Knock-in of mutant TDP43, knockout |
Ischemic Stroke
A1-type glycerophospholipase activity has been implicated in ischemic stroke through its role in astrocyte activation and neuroinflammation [1,5]. Inhibition of Lcn2, a protein associated with astrocyte reactivity, reduces ischemic stroke injury, suggesting that lipid-modifying enzymes contribute to the inflammatory cascade. Cottonseed oil alleviates ischemic stroke injury by inhibiting the inflammatory activation of microglia and astrocytes, further supporting the link between lipid metabolism and stroke pathology.
Sepsis-Associated Encephalopathy
In sepsis-associated encephalopathy, oxidative stress and ERK/NF-κB signaling in microglia and astrocytes contribute to neuroinflammation. Orexin-A attenuates this inflammatory response, indicating that modulation of lipid signaling pathways may be therapeutic. A1-type glycerophospholipase activity could be involved in generating lipid mediators that exacerbate or resolve inflammation in this context.
Chronic Pain and Neuroinflammation
Intrathecal administration of the STAT3 inhibitor Bt354 ameliorates chronic constriction injury-induced nociceptive sensitization by modulating neuroinflammation. Since STAT3 is a key regulator of inflammatory gene expression, and A1-type glycerophospholipase activity is linked to astrocyte activation, targeting this activity may offer a novel approach for chronic pain management [5,8].
Alzheimer's Disease and Cognitive Impairment
Huanglian Jiedu Decoction improves cognitive function in APP/PS1 mice by inhibiting NLRP3 inflammasome activation mediated by gut microbiota. This suggests that lipid-modifying enzymes, including A1-type glycerophospholipases, may influence Alzheimer's disease pathology through inflammasome regulation [4,5].
From A1-type glycerophospholipase activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does PLA1A knockout reduce A1-type glycerophospholipase activity? | CRISPR knockout in astrocytes or cell lines |
| Does a point mutation in the catalytic serine abolish activity? | CRISPR point mutation (e.g., S->A) |
| Can a tagged version of PLA1A be used for localization studies? | Knock-in of FLAG or GFP tag |
| Does overexpression of PLA1A induce A1 astrocyte phenotype? | CRISPR overexpression (e.g., CRISPRa) |
| Does LCN2 knockout protect against ischemic stroke? | Knockout mice subjected to MCAO |
| Does STAT3 inhibition modulate neuroinflammation? | Knock-in of STAT3 inhibitor-resistant mutant |
How to Study the A1-type glycerophospholipase activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Fluorogenic substrate assay | Enzymatic activity | High-throughput screening of inhibitors |
| Lipidomics (LC-MS) | Lipid species and products | Profiling of glycerophospholipid remodeling |
| CRISPR knockout screen | Gene function | Identification of regulators of A1 activity |
| CRISPR activation screen | Gene overexpression | Discovery of enhancers of A1 activity |
| Immunofluorescence | Protein localization | Subcellular distribution of PLA1A |
| Western blot | Protein expression | Validation of knockout or overexpression |
| qRT-PCR | mRNA levels | Gene expression analysis |
| RNA-seq | Transcriptome | Global changes in lipid metabolism genes |
Enzymatic Activity Assays
A1-type glycerophospholipase activity can be measured using fluorogenic or radioactive substrates that specifically report cleavage at the sn-1 position. These assays are typically performed with cell lysates or purified enzymes and can be adapted for high-throughput screening.
Lipidomics and Mass Spectrometry
Mass spectrometry-based lipidomics allows comprehensive profiling of glycerophospholipids and their hydrolysis products, providing insights into the substrate specificity and in vivo activity of A1-type glycerophospholipases. This method can quantify changes in lipid species following genetic or pharmacological manipulation.
CRISPR Screening
Genome-wide CRISPR knockout or activation screens can identify genes that regulate A1-type glycerophospholipase activity or its downstream effects. Such screens are powerful for discovering novel components of the lipid signaling network.
Imaging and Localization Studies
Fluorescence microscopy with tagged enzymes or lipid probes can reveal the subcellular localization and dynamics of A1-type glycerophospholipase activity. Live-cell imaging can track the generation of lysophospholipids in real time.
How CRISPR Can Be Used to Study GO:0140322 A1-type glycerophospholipase activity
Knockout
CRISPR knockout of genes encoding A1-type glycerophospholipases (e.g., PLA1A) can abolish enzymatic activity, allowing researchers to study loss-of-function phenotypes in neuroinflammation and lipid metabolism. Knockout models are essential for determining the causal role of these enzymes in diseases such as ischemic stroke.
Point Mutation
Introducing point mutations in the catalytic residues (e.g., serine to alanine) of A1-type glycerophospholipases can distinguish enzymatic activity from non-catalytic functions. Such models are valuable for dissecting the specific contribution of the catalytic activity to cellular processes.
Knock-in
Knock-in of tagged versions (e.g., FLAG, GFP) of A1-type glycerophospholipases enables localization and interaction studies without altering endogenous expression levels. Knock-in of disease-associated mutations can also model human genetic variants.
Overexpression
CRISPR activation (CRISPRa) or cDNA overexpression can increase A1-type glycerophospholipase activity, allowing researchers to study gain-of-function effects and identify downstream signaling pathways. Overexpression models are useful for screening for phenotypic changes in astrocytes and other cell types.
How EDITGENE Supports A1-type glycerophospholipase activity Research
Researchers studying A1-type glycerophospholipase activity-related genes often need to determine whether a candidate gene is causally involved in lipid signaling, neuroinflammation, or disease progression. EDITGENE provides a comprehensive suite of CRISPR services to enable such investigations, from knockout to precise point mutations and overexpression.
Contact EDITGENE today to design your custom CRISPR model for A1-type glycerophospholipase activity research.
Frequently Asked Questions About A1-type glycerophospholipase activity
What is A1-type glycerophospholipase activity?
A1-type glycerophospholipase activity (GO:0140322) is a molecular function that cleaves the fatty acid at the sn-1 position of glycerophospholipids, producing a free fatty acid and a lysophospholipid.
What genes are involved in A1-type glycerophospholipase activity?
Genes such as PLA1A encode enzymes with this activity, while LCN2, STAT3, and NLRP3 are associated with downstream inflammatory pathways [1,4,5,8].
How is A1-type glycerophospholipase activity measured?
It can be measured using fluorogenic or radioactive substrates specific for sn-1 cleavage, as well as lipidomics and mass spectrometry.
What diseases are linked to A1-type glycerophospholipase activity?
It has been implicated in ischemic stroke, sepsis-associated encephalopathy, chronic pain, and Alzheimer's disease [1,2,4,7,8].
What is the difference between A1-type and A2-type phospholipase activity?
A1-type cleaves at the sn-1 position, while A2-type cleaves at the sn-2 position of glycerophospholipids.
Can CRISPR be used to study A1-type glycerophospholipase activity?
Yes, CRISPR knockout, point mutation, knock-in, and overexpression models are powerful tools to dissect the function of genes with this activity.
What are the substrates of A1-type glycerophospholipase?
Common substrates include phosphatidylcholine and phosphatidylethanolamine, among other glycerophospholipids.
What is the role of A1-type glycerophospholipase in astrocytes?
It contributes to the A1 neurotoxic phenotype of astrocytes, which is associated with neuroinflammation.
How is A1-type glycerophospholipase activity regulated?
It is regulated by calcium, phosphorylation, and inflammatory stimuli such as P2X7 receptor activation.
What model systems are used to study A1-type glycerophospholipase activity?
Cell lines, primary astrocytes, and animal models (e.g., knockout mice) are commonly used [1,5].
Conclusion
A1-type glycerophospholipase activity (GO:0140322) is a key molecular function in lipid metabolism and neuroinflammation. Its role in astrocyte activation and disease pathology makes it an attractive target for therapeutic intervention. CRISPR-based models are essential for advancing our understanding of this activity and its contribution to human disease.
References
- 1. Xiao R et al.. 2025. Regulating astrocyte phenotype by Lcn2 inhibition toward ischemic stroke therapy.. Biomaterials 317:123102 PMID: 39836995
- 2. Liu M et al.. 2020. Cottonseed oil alleviates ischemic stroke injury by inhibiting the inflammatory activation of microglia and astrocyte.. J Neuroinflammation 17(1):270 PMID: 32917229
- 3. Liu Z et al.. 2025. TDP43 augments astrocyte inflammatory activity through mtDNA-cGAS-STING axis in NMOSD.. J Neuroinflammation 22(1):14 PMID: 39844196
- 4. Zhang Y et al.. 2025. Huanglian Jiedu Decoction improves the"central-peripheral"inflammatory microenvironment and enhances the cognitive function of APP/PS1 mice by inhibiting the activation of NLRP3 inflammasome mediated by gut microbiota.. Chin Med 20(1):123 PMID: 40770806
- 5. Campagno KE et al.. 2024. Increased Pan-Type, A1-Type, and A2-Type Astrocyte Activation and Upstream Inflammatory Markers Are Induced by the P2X7 Receptor.. Int J Mol Sci 25(16) PMID: 39201471
- 6. Han Y et al.. 2025. Urea functions as a risk signal driving astrocyte-mediated neuroinflammation following stroke.. J Neuroinflammation 22(1):296 PMID: 41286951
- 7. Guo J et al.. 2024. Orexin-A Attenuates the Inflammatory Response in Sepsis-Associated Encephalopathy by Modulating Oxidative Stress and Inhibiting the ERK/NF-κB Signaling Pathway in Microglia and Astrocytes.. CNS Neurosci Ther 30(11):e70096 PMID: 39508266
- 8. Cheng HJ et al.. 2025. Intrathecal STAT3 inhibitor Bt354 ameliorates chronic constriction injury-induced nociceptive sensitization by modulating neuroinflammation.. Neurotherapeutics 22(6):e00763 PMID: 41067955
