GO:0000250 lanosterol synthase activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0000250 lanosterol synthase activity catalyzes the cyclization of (S)-2,3-epoxysqualene to lanosterol, forming the sterol nucleus.
• The enzyme is encoded by LSS (lanosterol synthase) in humans and is a key branch-point enzyme in the mevalonate/cholesterol biosynthesis pathway.
• Lanosterol synthase activity is essential for cholesterol synthesis, and its inhibition or deficiency affects membrane integrity, steroid hormone production, and cell signaling.
• Dysregulation of lanosterol synthase is linked to endometrial cancer, tumor immune evasion, lens fibrosis, and age-related cataract.
• Research models include CRISPR knockout, point mutation, knock-in, and overexpression of LSS to study its role in disease and development.
• The enzyme is a target for natural product inhibitors and is studied for its role in plant and microbial sterol biosynthesis.
Description
Lanosterol synthase activity (GO:0000250) is a molecular function that catalyzes the committed step in sterol biosynthesis: the cyclization of (S)-2,3-epoxysqualene to lanosterol. This reaction forms the tetracyclic sterol nucleus, a fundamental structure for cholesterol and all steroid hormones in mammals. The enzyme is highly conserved across eukaryotes and is essential for membrane function and cellular signaling. In humans, lanosterol synthase is encoded by the LSS gene, and its activity is tightly regulated in response to cellular sterol levels. Because of its central role in the mevalonate pathway, lanosterol synthase has emerged as a target for cancer therapy, cataract prevention, and metabolic disorders. Researchers study this enzyme to understand cholesterol homeostasis, lipid metabolism, and the mechanisms of diseases ranging from cancer to lens opacity.
lanosterol synthase activity At A Glance
| GO ID | GO:0000250 |
|---|---|
| GO term | lanosterol synthase activity |
| Ontology | molecular_function |
| Synonym | 2,3-epoxysqualene lanosterol cyclase activity; 2,3-oxidosqualene-lanosterol cyclase activity; OSC; oxidosqualene--lanosterol cyclase activity; squalene-2,3-oxide-lanosterol cyclase activity |
| Major function | Catalyzes the cyclization of (S)-2,3-epoxysqualene to lanosterol, forming the sterol nucleus |
| Reaction | (S)-2,3-epoxysqualene = lanosterol |
| Pathway | Mevalonate/cholesterol biosynthesis pathway |
| Human gene | LSS (lanosterol synthase) |
| Inhibitors | Natural products such as digalactosyl diacylglycerols |
What Is GO:0000250?
According to the Gene Ontology, lanosterol synthase activity (GO:0000250) is defined as the catalysis of the reaction: (S)-2,3-epoxysqualene = lanosterol. This is a cyclization reaction that forms the sterol nucleus. In other words, the enzyme converts the linear epoxide (S)-2,3-epoxysqualene into the tetracyclic sterol lanosterol through a series of concerted cyclization steps.
Why Is lanosterol synthase activity Important in Cell Biology?
Lanosterol synthase activity is a critical control point in the mevalonate pathway, determining the flux toward cholesterol and other sterols. Its product, lanosterol, is the precursor for cholesterol, steroid hormones, bile acids, and vitamin D. Beyond its metabolic role, lanosterol synthase has been implicated in cancer progression, immune evasion, and lens epithelial fibrosis. Inhibiting this enzyme can suppress tumor growth and modulate immune responses, making it a potential therapeutic target. In the eye, lanosterol synthase activity is essential for lens transparency, and its deficiency or dysregulation contributes to cataract formation. Thus, understanding this enzyme's regulation and function is vital for developing treatments for metabolic, oncological, and ophthalmological diseases.
• Essential for cholesterol biosynthesis and membrane integrity.
• Provides precursors for steroid hormones, bile acids, and vitamin D.
• Implicated in endometrial cancer progression and MAPK/JNK signaling.
• Deficiency promotes tumor immune evasion via PDL1-dependent mechanisms.
• Prevents epithelial-mesenchymal transition (EMT) in lens fibrosis.
• Alleviates lens opacity in age-related cortical cataract.
• Target of natural product inhibitors with potential therapeutic applications.
• Plays a role in plant and microbial sterol biosynthesis.
• Regulated by ATR and mTORC1 signaling via de novo cholesterol synthesis.
• A promising target for cancer therapy and cataract prevention.
What Happens During lanosterol synthase activity?
Substrate binding and cyclization
In simple terms: The enzyme grabs a linear molecule and folds it into a ring structure.
Lanosterol synthase binds (S)-2,3-epoxysqualene, a linear 30-carbon epoxide, and catalyzes its cyclization to form the tetracyclic sterol lanosterol. This reaction involves a series of concerted ring closures and rearrangements, forming the sterol nucleus.
Formation of the sterol nucleus
In simple terms: The linear molecule becomes a four-ring steroid core.
The cyclization reaction produces the lanosterol skeleton, which contains the characteristic four fused rings of sterols. This step is the committed step in sterol biosynthesis and is essential for the production of cholesterol and other sterols.
Role in the mevalonate pathway
In simple terms: This enzyme is a key step in the assembly line that makes cholesterol.
Lanosterol synthase acts downstream of squalene epoxidase in the mevalonate pathway, converting (S)-2,3-epoxysqualene to lanosterol. Lanosterol is then further processed to cholesterol through a series of enzymatic reactions.
Regulation by cellular sterol levels
In simple terms: The cell adjusts this enzyme's activity based on how much cholesterol it needs.
Lanosterol synthase activity is regulated by feedback mechanisms that sense cellular sterol levels, often through SREBP1 and mTORC1 signaling. This ensures balanced production of cholesterol and other sterols.
Key Genes Involved in GO:0000250 lanosterol synthase activity
The following genes and proteins are directly involved in lanosterol synthase activity and its regulation.
| Gene | Major Role | Research Relevance |
|---|---|---|
| LSS | Encodes lanosterol synthase, catalyzing the cyclization of (S)-2,3-epoxysqualene to lanosterol | Target for cancer, cataract, and metabolic studies |
| SQLE | Squalene epoxidase, converts squalene to (S)-2,3-epoxysqualene upstream of LSS | Upstream regulator of lanosterol synthesis |
| SREBP1 | Transcription factor regulating lipogenic genes including LSS | Mediates EMT and lens fibrosis |
| mTORC1 | Kinase complex promoting de novo cholesterol synthesis via LSS | Links nutrient signaling to sterol biosynthesis |
| ATR | Kinase that promotes mTORC1 activity and cholesterol synthesis | DNA damage response and metabolic regulation |
| MAPK/JNK | Signaling pathway affected by LSS inhibition in endometrial cancer | Potential therapeutic target |
| PDL1 | Immune checkpoint protein upregulated upon LSS deficiency | Tumor immunosuppression |
| CYP51A1 | Lanosterol 14-alpha demethylase, downstream of LSS | Cholesterol biosynthesis |
| DHCR24 | 24-dehydrocholesterol reductase, involved in cholesterol synthesis | Sterol metabolism |
| HMGCR | Rate-limiting enzyme of mevalonate pathway upstream of LSS | Cholesterol homeostasis |
| FDFT1 | Squalene synthase, upstream of LSS | Sterol biosynthesis |
| MVK | Mevalonate kinase, upstream of LSS | Mevalonate pathway |
| PMVK | Phosphomevalonate kinase, upstream of LSS | Mevalonate pathway |
| MVD | Mevalonate decarboxylase, upstream of LSS | Mevalonate pathway |
| IDI1 | Isopentenyl-diphosphate delta isomerase 1, upstream of LSS | Mevalonate pathway |
| FDPS | Farnesyl diphosphate synthase, upstream of LSS | Mevalonate pathway |
| GGPS1 | Geranylgeranyl diphosphate synthase, upstream of LSS | Mevalonate pathway |
| SQLE | Squalene epoxidase, directly upstream of LSS | Sterol biosynthesis |
How Is lanosterol synthase activity Regulated?
Lanosterol synthase activity is regulated at multiple levels. Transcriptionally, the LSS gene is a target of SREBP1, which induces its expression under low sterol conditions. Post-translationally, the enzyme can be modulated by feedback inhibition by downstream sterols. Signaling pathways such as mTORC1 promote de novo cholesterol synthesis, including LSS activity, in response to nutrient availability. Additionally, ATR kinase promotes mTORC1 activity, indirectly enhancing cholesterol synthesis. In cancer, inhibition of lanosterol synthase links to MAPK/JNK signaling, suggesting crosstalk between sterol metabolism and stress-activated pathways.
lanosterol synthase activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| LSS | Endometrial cancer | CRISPR knockout in endometrial cancer cell lines |
| LSS | Tumor immunosuppression | LSS knockout in mouse tumor models |
| LSS | Lens fibrosis and cataract | LSS overexpression in lens epithelial cells |
| LSS | Cholesterol biosynthesis disorders | Point mutation knock-in in cell lines |
| LSS | Metabolic syndrome | Overexpression and knockout in hepatocytes |
Cancer
Lanosterol synthase activity is implicated in cancer progression. Inhibition of LSS suppresses endometrial cancer growth and is associated with MAPK/JNK signaling. LSS deficiency promotes tumor progression by orchestrating a PDL1-dependent immunosuppressive microenvironment, suggesting that LSS loss may contribute to immune evasion. These findings highlight LSS as a potential target for cancer therapy.
Cataract and lens fibrosis
Lanosterol synthase plays a protective role in the lens. It prevents epithelial-mesenchymal transition (EMT) during lens epithelial fibrosis by regulating SREBP1. The lanosterol synthase pathway alleviates lens opacity in age-related cortical cataract, indicating its therapeutic potential for cataract prevention.
Metabolic disorders
As a key enzyme in cholesterol biosynthesis, lanosterol synthase activity is linked to metabolic disorders. Its regulation by mTORC1 and ATR connects nutrient sensing to lipid metabolism. Dysregulation may contribute to conditions such as hypercholesterolemia and metabolic syndrome.
From lanosterol synthase activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does LSS loss affect tumor growth? | CRISPR knockout in cancer cell lines and xenografts |
| Does LSS point mutation alter enzyme activity? | Point mutation knock-in in HEK293 or HeLa cells |
| Does LSS overexpression prevent cataract? | Overexpression in lens epithelial cells |
| How does LSS regulate cholesterol synthesis? | Knockout and rescue with tagged LSS |
| What is the role of LSS in immune evasion? | LSS knockout in syngeneic mouse tumor models |
| Can LSS inhibitors suppress cancer? | Pharmacological inhibition in cell lines |
How to Study the lanosterol synthase activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| CRISPR knockout | Loss of LSS function | Cancer and metabolic studies |
| Point mutation knock-in | Effect of specific mutations on enzyme activity | Structure-function analysis |
| Overexpression | Gain of LSS function | Cataract and cholesterol studies |
| RNA-seq | Transcriptional changes upon LSS modulation | Pathway analysis |
| Lipidomics | Sterol and lipid profiles | Cholesterol synthesis measurement |
| Immunoblotting | Protein expression and signaling | MAPK/JNK and SREBP1 analysis |
| CRISPR library screening | Genetic interactions and modifiers | Target discovery |
CRISPR knockout
CRISPR knockout of LSS is used to study loss-of-function phenotypes, such as reduced cholesterol synthesis, altered cell proliferation, and tumor progression. Knockout cell lines can be analyzed by lipidomics, RNA-seq, and immunoblotting.
Point mutation knock-in
Point mutations in LSS can be introduced to study catalytic residues or regulatory sites, revealing how specific amino acids affect enzyme activity and substrate binding. These models are useful for structure-function studies.
Overexpression
Overexpression of LSS is used to investigate gain-of-function effects, such as protection against lens opacity or increased cholesterol synthesis. Overexpression models can be combined with metabolic assays and imaging.
Library screening and bioinformatics
CRISPR library screening can identify synthetic lethal interactions with LSS or modifiers of its activity. Bioinformatics analysis of transcriptomic and lipidomic data helps elucidate pathways regulated by LSS.
How CRISPR Can Be Used to Study GO:0000250 lanosterol synthase activity
Knockout
CRISPR knockout of LSS is used to completely ablate lanosterol synthase activity, enabling studies of its essential role in cholesterol synthesis and disease progression. Knockout models have revealed that LSS loss suppresses endometrial cancer growth and promotes tumor immune evasion.
Point Mutation
Point mutation knock-in allows precise modification of catalytic residues or regulatory sites in LSS, helping to dissect the molecular mechanism of cyclization and regulation. Such models are valuable for understanding how mutations affect enzyme kinetics and substrate specificity.
Knock-in
Knock-in of tagged LSS (e.g., GFP or FLAG) enables visualization and purification of the enzyme for interaction studies and localization. This approach can also be used to introduce disease-associated mutations.
Overexpression
Overexpression of LSS via CRISPR activation or lentiviral vectors is used to study gain-of-function effects, such as protection against lens fibrosis and cataract. Overexpression models help identify downstream targets and therapeutic potential.
How EDITGENE Supports lanosterol synthase activity Research
Researchers studying lanosterol synthase activity-related genes often need to determine whether a candidate gene is causally involved in sterol metabolism, cancer, or lens biology. EDITGENE provides comprehensive CRISPR services to create precise cellular models for such investigations.
Contact EDITGENE today to design your custom CRISPR model for lanosterol synthase activity research.
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| LSS Knockout HEK293 Cell Line | EDJ-KQ3741 | Human | 4047 | Details Get a Quote |
| LSS Knockout A-549 Cell Line | EDJ-KQ25800 | Human | 4047 | Details Get a Quote |
| LSS Knockout HCT 116 Cell Line | EDJ-KQ25801 | Human | 4047 | Details Get a Quote |
| LSS Knockout HeLa Cell Line | EDJ-KQ25802 | Human | 4047 | Details Get a Quote |
Displaying Records 1 To 4 Of 4 Records
Frequently Asked Questions About lanosterol synthase activity
What is lanosterol synthase activity?
Lanosterol synthase activity (GO:0000250) is the enzymatic activity that catalyzes the cyclization of (S)-2,3-epoxysqualene to lanosterol, forming the sterol nucleus.
What genes are involved in lanosterol synthase activity?
The primary gene is LSS, which encodes lanosterol synthase. Other genes in the pathway include SQLE, SREBP1, mTORC1, and ATR.
What diseases are associated with lanosterol synthase?
Lanosterol synthase is associated with endometrial cancer, tumor immunosuppression, lens fibrosis, and age-related cataract.
How is lanosterol synthase regulated?
It is regulated by SREBP1, mTORC1, and feedback mechanisms responding to cellular sterol levels.
What is the reaction catalyzed by lanosterol synthase?
The reaction is (S)-2,3-epoxysqualene = lanosterol, a cyclization that forms the sterol nucleus.
Can lanosterol synthase be targeted for cancer therapy?
Yes, inhibition of lanosterol synthase suppresses endometrial cancer growth and may modulate immune responses.
What are the research models for lanosterol synthase?
Common models include CRISPR knockout, point mutation knock-in, overexpression, and CRISPR library screening in cell lines and animal models.
What is the role of lanosterol synthase in the eye?
It prevents EMT during lens fibrosis and alleviates lens opacity in age-related cataract.
What are natural inhibitors of lanosterol synthase?
Digalactosyl diacylglycerols have been shown to inhibit human lanosterol synthase.
How does lanosterol synthase affect cholesterol synthesis?
It catalyzes a key step in the mevalonate pathway, producing lanosterol, which is further converted to cholesterol.
Conclusion
Lanosterol synthase activity (GO:0000250) is a fundamental enzymatic function in sterol biosynthesis, with critical roles in cholesterol production, cancer progression, and lens biology. Its regulation by SREBP1 and mTORC1 links nutrient sensing to lipid metabolism. Dysregulation of LSS contributes to endometrial cancer, tumor immune evasion, and cataract formation, making it a promising therapeutic target. Advances in CRISPR-based models and bioinformatics will continue to elucidate its mechanisms and facilitate drug discovery.
References
- 1. Hou M et al.. 2021. Ginsenosides in Panax genus and their biosynthesis.. Acta Pharm Sin B 11(7):1813-1834 PMID: 34386322
- 2. Ma L et al.. 2025. Inhibition of lanosterol synthase linking with MAPK/JNK signaling pathway suppresses endometrial cancer.. Cell Death Discov 11(1):55 PMID: 39922821
- 3. Ma P et al.. 2023. Lanosterol Synthase Prevents EMT During Lens Epithelial Fibrosis Via Regulating SREBP1.. Invest Ophthalmol Vis Sci 64(15):12 PMID: 38079167
- 4. Tangudu NK et al.. 2025. ATR promotes mTORC1 activity via de novo cholesterol synthesis.. EMBO Rep 26(14):3574-3593 PMID: 40514450
- 5. Gao Y et al.. 2024. Lanosterol synthase deficiency promotes tumor progression by orchestrating PDL1-dependent tumor immunosuppressive microenvironment.. MedComm (2020) 5(4):e528 PMID: 38606362
- 6. Shen X et al.. 2018. Lanosterol Synthase Pathway Alleviates Lens Opacity in Age-Related Cortical Cataract.. J Ophthalmol 2018:4125893 PMID: 30116630
- 7. Tanaka R et al.. 2005. Synthesis of digalactosyl diacylglycerols and their structure-inhibitory activity on human lanosterol synthase.. Bioorg Med Chem Lett 15(1):159-62 PMID: 15582431
