GO:1902046 positive regulation of Fas signaling pathway: Apoptosis Signaling Pathway, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:1902046 describes any process that activates or increases the frequency, rate or extent of Fas signaling pathway.
• Fas signaling is triggered by Fas ligand (FasL) binding to the Fas receptor (FasR/CD95/Apo-1), leading to caspase activation and apoptosis.
• Positive regulation of Fas signaling is critical for immune surveillance, T-cell immunotherapy, and elimination of cancer cells.
• Dysregulated Fas signaling contributes to autoimmune diseases, cancer progression, and resistance to apoptosis.
• Key genes include FAS, FASLG, FADD, CASP8, CASP3, and regulators such as BID, BAX, and c-FLIP [1,6].
• CRISPR knockout, knock-in, and overexpression models enable precise dissection of positive regulators of Fas signaling [1,6].
Description
The Gene Ontology term GO:1902046, positive regulation of Fas signaling pathway, encompasses any process that activates or increases the frequency, rate or extent of the Fas signaling pathway. Fas signaling, also known as CD95 or Apo-1 signaling, is a major extrinsic apoptotic pathway triggered by the binding of Fas ligand (FasL) to the Fas receptor. This pathway is essential for immune homeostasis, elimination of infected or transformed cells, and maintenance of peripheral tolerance. Researchers study positive regulators of Fas signaling to understand how cells sensitize or resist apoptosis, with implications for cancer immunotherapy, autoimmunity, and infectious diseases [1,6]. Positive regulation of Fas signaling can occur at multiple levels, including increased Fas receptor expression, enhanced FasL availability, facilitation of death-inducing signaling complex (DISC) formation, and amplification of caspase activation. For example, in T-cell immunotherapy, Fas-mediated off-target tumor killing is a critical mechanism by which engineered T cells eliminate cancer cells. In colorectal cancer, Fas signaling can induce stemness properties through regulation of Bmi1, highlighting context-dependent outcomes. Understanding the molecular players and regulatory mechanisms of this process is vital for developing targeted therapies. This article integrates authoritative QuickGO data and verified PubMed literature to provide a comprehensive overview of GO:1902046, covering its definition, mechanisms, key genes, disease relevance, and experimental models including CRISPR-based approaches [1,6].
positive regulation of Fas signaling pathway At A Glance
| GO ID | GO:1902046 |
|---|---|
| GO term | positive regulation of Fas signaling pathway |
| Ontology | biological_process |
| Synonym | activation of Fas signaling pathway; upregulation of CD95 signaling pathway; positive regulation of Apo-1 signaling pathway |
| Major function | Increases the frequency, rate or extent of Fas signaling, leading to apoptosis and other cellular responses |
| Related pathway | Fas/CD95/Apo-1 extrinsic apoptotic signaling pathway |
| Key ligands | Fas ligand (FasL/CD95L) |
| Key receptors | Fas receptor (FasR/CD95/Apo-1/TNFRSF6) |
| Downstream effectors | FADD, caspase-8, caspase-3, BID, BAX |
What Is GO:1902046?
GO:1902046 is defined as any process that activates or increases the frequency, rate or extent of the Fas signaling pathway. In other words, it includes molecular events that positively regulate the cascade initiated by Fas ligand binding to the Fas receptor, leading to downstream signaling such as caspase activation and apoptosis. This term is a child of positive regulation of signal transduction and is specific to the Fas/CD95/Apo-1 pathway.
Why Is positive regulation of Fas signaling pathway Important in Cell Biology?
Positive regulation of Fas signaling is crucial for immune surveillance, tissue homeostasis, and cancer therapy. Enhancing Fas signaling can promote apoptosis of tumor cells, as demonstrated in T-cell immunotherapy where Fas-mediated off-target tumor killing contributes to efficacy. Conversely, dysregulated positive regulation can lead to excessive apoptosis in autoimmune diseases or tissue damage. Understanding this process aids in designing strategies to modulate Fas signaling for therapeutic benefit, including CRISPR-based screens to identify novel regulators [1,6].
• Enhances elimination of cancer cells in T-cell immunotherapy.
• Modulates immune homeostasis and peripheral tolerance.
• Contributes to stemness properties in colorectal cancer via Bmi1 regulation.
• Influences sensitivity to anti-PD-L1 therapy in B-lymphoma.
• Plays a role in fatty acid metabolism and lymph node metastasis in cervical cancer.
• Affects tissue-resident memory T cell activity in colorectal cancer.
• Associated with prognostic models in renal cell carcinoma.
• Can be hijacked by viruses, e.g., African swine fever virus modulates lipid metabolism.
• Potential target for autoimmune and inflammatory diseases.
• Key focus for CRISPR screening to identify positive regulators [1,6].
What Happens During positive regulation of Fas signaling pathway?
FasL binding and receptor trimerization
In simple terms: Fas ligand binds to Fas receptor, causing receptors to cluster and activate.
Positive regulation can begin with increased expression or availability of Fas ligand (FasL), which binds to the Fas receptor (FasR/CD95/Apo-1) on target cells. This binding induces trimerization of Fas receptors, a critical step for initiating downstream signaling. Enhanced FasL expression or receptor clustering amplifies the signal, leading to more efficient apoptosis induction.
DISC formation and caspase-8 activation
In simple terms: The receptor recruits adaptor proteins and caspases to form a death-inducing signaling complex.
Upon trimerization, the Fas receptor recruits the adaptor protein FADD via death domain interactions, which in turn recruits procaspase-8 to form the death-inducing signaling complex (DISC). Positive regulation can involve increased FADD recruitment or enhanced DISC stability, promoting autocatalytic activation of caspase-8. Active caspase-8 then cleaves downstream effector caspases such as caspase-3, leading to apoptosis.
Mitochondrial amplification via BID cleavage
In simple terms: Caspase-8 can cleave BID to engage the mitochondrial apoptotic pathway, amplifying the death signal.
In some cell types, caspase-8 cleaves the BH3-only protein BID to generate truncated BID (tBID), which translocates to mitochondria and induces cytochrome c release through BAX/BAK activation. This mitochondrial amplification loop enhances caspase activation and ensures robust apoptosis. Positive regulators of Fas signaling may promote this crosstalk, increasing sensitivity to Fas-induced death.
Regulation by c-FLIP and other modulators
In simple terms: Proteins like c-FLIP can inhibit caspase-8 activation, so positive regulators may overcome this block.
Cellular FLICE-like inhibitory protein (c-FLIP) competes with caspase-8 for DISC binding, acting as a negative regulator. Positive regulation of Fas signaling can occur by downregulating c-FLIP or enhancing its degradation, thereby sensitizing cells to Fas-induced apoptosis. Other modulators include Bcl-2 family proteins and IAPs, which can be targeted to amplify the pathway.
Transcriptional and post-translational control
In simple terms: Cells can increase Fas signaling by making more Fas receptor or modifying existing proteins.
Positive regulation often involves transcriptional upregulation of FAS or FASLG genes, increasing receptor or ligand levels. Post-translational modifications such as phosphorylation, ubiquitination, or palmitoylation of Fas or DISC components can also enhance signaling. For example, Fas palmitoylation promotes its localization to lipid rafts, facilitating efficient DISC formation.
Key Genes Involved in GO:1902046 positive regulation of Fas signaling pathway
The following genes and proteins are central to the positive regulation of Fas signaling pathway, based on verified literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| FAS | Encodes Fas receptor (CD95/Apo-1); initiates apoptotic signaling upon ligand binding | Target for knockout/knock-in to study receptor function and regulation |
| FASLG | Encodes Fas ligand; binds Fas receptor to trigger trimerization and DISC formation | Overexpression or knockout models to modulate ligand availability |
| FADD | Adaptor protein recruiting caspase-8 to Fas receptor; essential for DISC formation | Knockout studies to dissect DISC assembly and positive regulation |
| CASP8 | Initiates caspase cascade; activates downstream effector caspases | Point mutations to assess catalytic activity and regulation |
| CASP3 | Effector caspase executing apoptosis; cleaved by caspase-8 | Knockout to confirm apoptotic execution |
| BID | BH3-only protein cleaved by caspase-8 to amplify mitochondrial apoptosis | Knock-in of cleavage-resistant mutants to study amplification |
| BAX | Pro-apoptotic Bcl-2 family member; mediates cytochrome c release | Knockout to test mitochondrial dependence |
| BCL2 | Anti-apoptotic protein; inhibits BAX/BAK and mitochondrial amplification | Overexpression to test resistance to Fas signaling |
| CFLAR | Encodes c-FLIP; inhibits caspase-8 activation at DISC | Knockdown/knockout to enhance Fas signaling |
| BIRC5 | Encodes survivin; inhibits caspases and regulates apoptosis | Knockout to sensitize cells to Fas-induced death |
| Bmi1 | Polycomb group protein; Fas signaling induces stemness via Bmi1 regulation | Knockout/overexpression in colorectal cancer models |
| PDCD1 | Encodes PD-1; interacts with Fas signaling in immune cells | Knockout in T cells to study immunotherapy synergy |
| CD274 | Encodes PD-L1; modulates Fas-mediated killing in lymphoma | Knockout/knock-in to assess anti-PD-L1 response |
| FABP5 | Fatty acid binding protein; promotes metastasis and may modulate Fas signaling | Knockout in cervical cancer models |
| CD69 | Tissue-resident memory T cell marker; associated with anti-tumor activity | Knockout/overexpression to study T cell function |
| CD103 | Integrin marking tissue-resident memory T cells; correlates with Fas signaling | Knockout models to assess residency and cytotoxicity |
| GZMB | Granzyme B; serine protease involved in cytotoxic T cell killing | Knockout to study alternative killing pathways |
| PRF1 | Perforin; pore-forming protein in cytotoxic lymphocytes | Knockout to dissect Fas-dependent vs. independent killing |
How Is positive regulation of Fas signaling pathway Regulated?
Positive regulation of Fas signaling is controlled at multiple levels. Transcriptional upregulation of FAS and FASLG increases pathway activity. Post-translational modifications, including palmitoylation and phosphorylation of Fas, enhance DISC formation. Negative regulators such as c-FLIP and Bcl-2 can be downregulated or inhibited to promote signaling. In cancer, oncogenic pathways may suppress Fas signaling, while immunotherapy can restore or enhance it [1,6]. Additionally, metabolic reprogramming, such as fatty acid metabolism mediated by FABP5, may influence Fas signaling in metastasis.
positive regulation of Fas signaling pathway and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| FAS | Cancer, autoimmunity, lymphoproliferative disorders | Knockout mice or cell lines; point mutations in death domain |
| FASLG | Autoimmune lymphoproliferative syndrome, cancer | Overexpression or knockout in T cells |
| CASP8 | Immunodeficiency, cancer susceptibility | Knock-in of catalytic mutants; knockout |
| CFLAR | Cancer resistance to apoptosis | Knockdown/knockout to sensitize cells |
| Bmi1 | Colorectal cancer stemness | Knockout and overexpression in colorectal cancer models |
Cancer and immunotherapy
Positive regulation of Fas signaling is exploited in T-cell immunotherapy to kill tumor cells. Fas-mediated off-target tumor killing is a critical mechanism of efficacy in engineered T cells. In colorectal cancer, Fas signaling induces stemness properties via Bmi1, potentially contributing to therapy resistance. In B-lymphoma, miR155 sensitizes cells to anti-PD-L1 antibody through PD-1/PD-L1-mediated interaction with CD8+ T cells, involving Fas signaling. Prognostic models in renal cell carcinoma incorporate CD8+ T cell signatures linked to Fas signaling.
Autoimmunity and inflammation
Excessive positive regulation of Fas signaling can lead to tissue damage and autoimmune diseases. Enhanced Fas-mediated apoptosis contributes to beta-cell destruction in type 1 diabetes and other autoimmune conditions. Modulating positive regulators may offer therapeutic strategies to limit unwanted apoptosis.
Viral infection and immune evasion
Viruses can hijack cellular pathways to modulate Fas signaling. African swine fever virus induces chaperone-mediated autophagy and lipolysis to upregulate fatty acid β-oxidation, promoting viral replication. This metabolic reprogramming may intersect with Fas signaling, affecting cell survival and immune evasion.
Metabolic and metastatic diseases
FABP5 promotes lymph node metastasis in cervical cancer by reprogramming fatty acid metabolism, which may influence Fas signaling and apoptosis sensitivity. Positive regulation of Fas signaling in this context could be targeted to prevent metastasis.
From positive regulation of Fas signaling pathway-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does gene X positively regulate Fas signaling? | CRISPR knockout of gene X followed by FasL treatment and apoptosis assay |
| Does a specific point mutation in FAS affect signaling? | CRISPR knock-in of point mutation in FAS gene |
| Does overexpression of gene Y enhance Fas-induced apoptosis? | CRISPR activation (CRISPRa) or lentiviral overexpression |
| What is the role of a candidate gene in T-cell immunotherapy? | Knockout in primary T cells followed by cytotoxicity assay |
| How does metabolic gene Z affect Fas signaling? | Knockout in cancer cell lines and lipid metabolism profiling |
| Can we identify novel positive regulators? | Genome-wide CRISPR library screening with FasL selection |
How to Study the positive regulation of Fas signaling pathway Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Annexin V/PI flow cytometry | Apoptosis | Quantify Fas-induced cell death |
| Caspase-3/7 activity assay | Caspase activation | Measure DISC downstream signaling |
| RNA-seq | Transcriptional changes | Identify genes upregulated by Fas signaling |
| Phosphoproteomics | Phosphorylation events | Map signaling pathways |
| CRISPR knockout screen | Gene requirement | Identify positive regulators |
| CRISPR activation screen | Gene overexpression effects | Discover enhancers of Fas signaling |
| Western blot | Protein expression and cleavage | Detect caspase-8, BID, etc. |
| Immunoprecipitation | Protein interactions | Study DISC composition |
CRISPR knockout and knock-in models
CRISPR/Cas9-mediated knockout of candidate genes allows assessment of their requirement for Fas signaling. Knock-in of point mutations or tags enables precise dissection of protein function and localization. These models are essential for validating positive regulators identified in screens.
Apoptosis assays
Fas-induced apoptosis can be measured by flow cytometry using Annexin V/propidium iodide staining, caspase-3/7 activity assays, or TUNEL staining. These assays quantify the extent of positive regulation and identify sensitizers or resistance mechanisms.
Transcriptomics and proteomics
RNA-seq and proteomics can identify genes and proteins differentially expressed upon Fas stimulation, revealing positive regulators. Phosphoproteomics can uncover signaling events downstream of Fas.
CRISPR library screening
Genome-wide CRISPR knockout or activation screens with FasL treatment can identify positive and negative regulators of Fas signaling. Hits are validated individually using the models above.
How CRISPR Can Be Used to Study GO:1902046 positive regulation of Fas signaling pathway
Knockout
CRISPR knockout of candidate genes is used to determine whether they are necessary for positive regulation of Fas signaling. For example, knocking out FADD or CASP8 abolishes Fas-induced apoptosis, confirming their essential roles. Knockout of negative regulators like CFLAR enhances signaling.
Point Mutation
Point mutations can be introduced via CRISPR to study specific residues in Fas, FADD, or caspase-8. For instance, mutation of the Fas death domain can disrupt FADD binding, while catalytic dead caspase-8 mutants reveal non-apoptotic functions.
Knock-in
Knock-in of tags (e.g., GFP, HA) or reporter genes allows visualization and tracking of Fas signaling components. Knock-in of cleavage-resistant BID mutants helps dissect mitochondrial amplification.
Overexpression
CRISPR activation (CRISPRa) or lentiviral overexpression can increase expression of positive regulators to enhance Fas signaling. Overexpression of FasL or Fas sensitizes cells to apoptosis and is used in immunotherapy models.
How EDITGENE Supports positive regulation of Fas signaling pathway Research
Researchers studying positive regulation of Fas signaling pathway-related genes often need to determine whether a candidate gene is causally involved in enhancing or modulating the pathway. EDITGENE provides comprehensive CRISPR-based services to accelerate this research, from knockout to knock-in and library screening.
Contact EDITGENE today to design your custom CRISPR model for positive regulation of Fas signaling pathway research.
Frequently Asked Questions About positive regulation of Fas signaling pathway
What is GO:1902046?
GO:1902046 is the Gene Ontology term for positive regulation of Fas signaling pathway, defined as any process that activates or increases the frequency, rate or extent of Fas signaling.
What genes are involved in positive regulation of Fas signaling pathway?
Key genes include FAS, FASLG, FADD, CASP8, CASP3, BID, BAX, CFLAR, and Bmi1, among others [1,6].
How does Fas signaling induce apoptosis?
Fas ligand binding to Fas receptor triggers DISC formation, caspase-8 activation, and downstream caspase-3 activation, leading to apoptosis.
What diseases are associated with dysregulated Fas signaling?
Cancer, autoimmune diseases, and viral infections can involve dysregulated Fas signaling [1,5,6].
How can CRISPR be used to study positive regulation of Fas signaling?
CRISPR knockout, knock-in, point mutation, and overexpression models allow functional dissection of genes in the pathway.
What is the role of Fas signaling in T-cell immunotherapy?
Fas-mediated off-target tumor killing is a critical mechanism by which T-cell immunotherapy eliminates cancer cells.
What is the difference between Fas signaling and Fas-mediated apoptosis?
Fas signaling encompasses all downstream events, while Fas-mediated apoptosis is the specific cell death outcome.
Can positive regulation of Fas signaling be targeted therapeutically?
Yes, enhancing Fas signaling is explored in cancer therapy, while inhibiting it may benefit autoimmune conditions [1,6].
What are the main methods to study positive regulation of Fas signaling?
Common methods include apoptosis assays, CRISPR screens, RNA-seq, proteomics, and Western blot.
What cell models are available for studying Fas signaling?
EDITGENE offers knockout, point mutation, knock-in, overexpression cell models, and CRISPR library screening.
Conclusion
Positive regulation of Fas signaling pathway (GO:1902046) is a critical biological process with broad implications in cancer, immunology, and disease. Understanding its molecular mechanisms and key regulators can inform therapeutic strategies, including immunotherapy and targeted modulation of apoptosis. CRISPR-based models and screening approaches are powerful tools to dissect this pathway and identify novel drug targets [1,6].
References
- 1. Upadhyay R et al.. 2021. A Critical Role for Fas-Mediated Off-Target Tumor Killing in T-cell Immunotherapy.. Cancer Discov 11(3):599-613 PMID: 33334730
- 2. Zhang C et al.. 2020. FABP5 promotes lymph node metastasis in cervical cancer by reprogramming fatty acid metabolism.. Theranostics 10(15):6561-6580 PMID: 32550890
- 3. Wu ZX et al.. 2024. CD69(+)CD103(+)CD8(+) tissue-resident memory T cells possess stronger anti-tumor activity and predict better prognosis in colorectal cancer.. Cell Commun Signal 22(1):608 PMID: 39696312
- 4. Liu J et al.. 2024. Identification of a seven-gene prognostic model for renal cell carcinoma associated with CD8+T lymphocyte cell.. Medicine (Baltimore) 103(40):e39938 PMID: 39465721
- 5. Yang X et al.. 2026. African swine fever virus hijacks lipolysis induced by chaperone-mediated autophagy to upregulate fatty acid β-oxidation and promote viral replication.. mBio 17(4):e0336825 PMID: 41801037
- 6. Chen J et al.. 2017. Fas signaling induces stemness properties in colorectal cancer by regulation of Bmi1.. Mol Carcinog 56(10):2267-2278 PMID: 28543447
- 8. Zheng Z et al.. 2019. MiR155 sensitized B-lymphoma cells to anti-PD-L1 antibody via PD-1/PD-L1-mediated lymphoma cell interaction with CD8+T cells.. Mol Cancer 18(1):54 PMID: 30925928
