GO:2001241 positive regulation of extrinsic apoptotic signaling pathway in absence of ligand: Dependence Receptor Signaling, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:2001241 describes any process that activates or increases the frequency, rate or extent of the extrinsic apoptotic signaling pathway in absence of ligand, a process also known as dependence receptor signaling.
• The term is a biological_process child of extrinsic apoptotic signaling pathway in absence of ligand and is closely linked to positive regulation of apoptotic signaling pathway.
• Dependence receptors such as DCC, UNC5, and p75NTR trigger apoptosis when their ligands are absent, and this pro-apoptotic signaling is positively regulated by co-receptors, proteases, and adaptor proteins.
• Loss of dependence receptor signaling contributes to tumorigenesis, neurodegeneration, and developmental disorders, making GO:2001241 a key term for cancer and neurobiology research.
• Experimental models for GO:2001241 include CRISPR knockout, point mutation, knock-in, and overexpression cell lines, combined with apoptosis assays, transcriptomics, and proteomics.
• EDITGENE provides end-to-end CRISPR services, including knockout, point mutation, knock-in, overexpression, library screening, and bioinformatics, to dissect dependence receptor pathways.
Description
GO:2001241, positive regulation of extrinsic apoptotic signaling pathway in absence of ligand, is a Gene Ontology biological_process term that captures the cellular mechanisms amplifying apoptosis when dependence receptors are unoccupied. This term is essential for understanding how cells sense ligand availability and commit to programmed cell death, a process critical in development, tissue homeostasis, and disease. Dependence receptors, including DCC, UNC5, and p75NTR, induce apoptosis in the absence of their ligands, and their pro-apoptotic activity is positively regulated by co-receptors, proteolytic cleavage, and adaptor proteins. Researchers studying cancer, neurodegeneration, and developmental disorders increasingly focus on this pathway because its dysregulation can drive tumorigenesis or neuronal loss. The term is also relevant for drug discovery, as modulating dependence receptor signaling may offer therapeutic opportunities. Understanding GO:2001241 requires integrating molecular, cellular, and organismal data, and CRISPR-based models are powerful tools for dissecting its components.
positive regulation of extrinsic apoptotic signaling pathway in absence of ligand At A Glance
| GO ID | GO:2001241 |
|---|---|
| GO term | positive regulation of extrinsic apoptotic signaling pathway in absence of ligand |
| Ontology | biological_process |
| Synonym | positive regulation of dependence receptor signaling pathway; positive regulation of extrinsic apoptosis in absence of ligand; positive regulation of extrinsic apoptotic signalling pathway in absence of ligand |
| Major function | Enhances apoptosis triggered by unliganded dependence receptors |
| Parent term | extrinsic apoptotic signaling pathway in absence of ligand |
| Related term | positive regulation of apoptotic signaling pathway |
| Cellular context | Plasma membrane, cytoplasm, mitochondria |
| Key molecules | DCC, UNC5, p75NTR, caspase-8, caspase-3, DRAL, TUCAN |
What Is GO:2001241?
GO:2001241 is defined as any process that activates or increases the frequency, rate or extent of the extrinsic apoptotic signaling pathway in absence of ligand. In other words, it encompasses the positive regulatory events that enhance apoptosis triggered by dependence receptors when their ligands are unavailable. This term is a child of extrinsic apoptotic signaling pathway in absence of ligand and is synonymous with positive regulation of dependence receptor signaling pathway, positive regulation of extrinsic apoptosis in absence of ligand, and positive regulation of extrinsic apoptotic signalling pathway in absence of ligand.
Why Is positive regulation of extrinsic apoptotic signaling pathway in absence of ligand Important in Cell Biology?
GO:2001241 is important because it governs a fundamental cell-fate decision: whether a cell survives or dies when dependence receptors are not bound by their ligands. This process is critical for embryonic development, neuronal wiring, and tumor suppression, and its dysregulation is implicated in cancer, neurodegeneration, and developmental disorders. Understanding the positive regulation of this pathway can reveal therapeutic targets for diseases where apoptosis is misregulated.
• Controls apoptosis in the absence of ligands for dependence receptors, a key tumor suppressor mechanism.
• Dysregulation is linked to cancer, as loss of dependence receptor signaling promotes tumorigenesis.
• Implicated in neurodegeneration, where excessive apoptosis contributes to neuronal loss.
• Plays a role in developmental processes such as axon guidance and neural tube closure.
• Provides targets for therapeutic intervention in cancers and neurodegenerative diseases.
• Helps explain how cells interpret ligand availability to make life-or-death decisions.
• Involved in immune cell homeostasis and elimination of autoreactive cells.
• Serves as a model for studying extrinsic apoptosis regulation.
• Relevant to drug discovery, as modulators of dependence receptors are being explored.
• Enables researchers to dissect signaling crosstalk between apoptosis and other pathways.
What Happens During positive regulation of extrinsic apoptotic signaling pathway in absence of ligand?
Ligand absence and receptor activation
In simple terms: When a dependence receptor is not bound by its ligand, it changes shape and starts a death signal.
In the absence of ligand, dependence receptors such as DCC, UNC5, and p75NTR undergo conformational changes that expose pro-apoptotic domains. This activation is the first step in the extrinsic apoptotic signaling pathway in absence of ligand, and positive regulation of this step can involve co-receptors or accessory proteins that stabilize the active receptor conformation.
Recruitment of adaptor and effector proteins
In simple terms: The activated receptor recruits a set of proteins that relay the death signal inside the cell.
Upon activation, dependence receptors recruit adaptor proteins such as DRAL, TUCAN, and caspase-8 to form a signaling complex. Positive regulation of this pathway can occur through increased expression or post-translational modification of these adaptors, enhancing complex assembly and downstream signaling.
Caspase activation and amplification
In simple terms: The death signal activates caspases, which are proteases that dismantle the cell.
The receptor complex activates initiator caspases, such as caspase-8, which then cleave and activate effector caspases like caspase-3. Positive regulation of this pathway includes mechanisms that amplify caspase activation, such as mitochondrial amplification loops involving cytochrome c release.
Apoptosome formation and mitochondrial involvement
In simple terms: Mitochondria release factors that further boost the death signal.
In some contexts, the extrinsic pathway crosstalks with the intrinsic pathway through BH3-only proteins and mitochondrial outer membrane permeabilization. Positive regulation of the absence-of-ligand pathway can involve upregulation of pro-apoptotic Bcl-2 family members, leading to apoptosome formation and enhanced caspase activation.
Feedback and crosstalk with survival pathways
In simple terms: Survival signals can counteract the death signal, and positive regulators tip the balance toward apoptosis.
Positive regulation of GO:2001241 can also involve inhibition of pro-survival pathways, such as PI3K/AKT or NF-kB, which normally suppress apoptosis. For example, dependence receptor signaling can inhibit AKT activation, thereby promoting cell death.
Key Genes Involved in GO:2001241 positive regulation of extrinsic apoptotic signaling pathway in absence of ligand
The following genes and proteins are central to the positive regulation of the extrinsic apoptotic signaling pathway in absence of ligand, based on published literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| DCC | Dependence receptor; induces apoptosis when netrin-1 is absent | Colorectal cancer, neuronal development |
| UNC5A | Dependence receptor; pro-apoptotic in absence of netrin-1 | Neurodegeneration, cancer |
| UNC5B | Dependence receptor; regulates apoptosis and angiogenesis | Vascular biology, cancer |
| UNC5C | Dependence receptor; tumor suppressor | Colorectal cancer, neurodegeneration |
| UNC5D | Dependence receptor; pro-apoptotic | Neuroblastoma, cancer |
| p75NTR | Dependence receptor; mediates apoptosis in absence of neurotrophins | Neurodegeneration, development |
| CASP8 | Initiator caspase; activated by dependence receptors | Apoptosis, cancer |
| CASP3 | Effector caspase; executes apoptosis | Apoptosis, cancer |
| DRAL | Adaptor protein; facilitates receptor complex assembly | Apoptosis regulation |
| TUCAN | Caspase recruitment domain protein; modulates apoptosis | Cancer, inflammation |
| BID | BH3-only protein; links extrinsic and intrinsic apoptosis | Apoptosis, cancer |
| BAX | Pro-apoptotic Bcl-2 family member; mitochondrial permeabilization | Apoptosis, cancer |
| BAK | Pro-apoptotic Bcl-2 family member; mitochondrial permeabilization | Apoptosis, cancer |
| CYCS | Cytochrome c; released from mitochondria to activate apoptosome | Apoptosis |
| APAF1 | Apoptosome component; activates caspase-9 | Apoptosis |
| CASP9 | Initiator caspase; activated by apoptosome | Apoptosis |
| AKT1 | Survival kinase; inhibited by dependence receptor signaling | Cancer, survival signaling |
| NFKB1 | Transcription factor; pro-survival; counteracted by dependence receptors | Inflammation, cancer |
How Is positive regulation of extrinsic apoptotic signaling pathway in absence of ligand Regulated?
The positive regulation of the extrinsic apoptotic signaling pathway in absence of ligand is controlled at multiple levels. Transcriptional regulation of dependence receptors and their adaptors can modulate pathway sensitivity. Post-translational modifications, such as phosphorylation and ubiquitination, affect receptor stability and complex formation. Proteolytic cleavage of receptors by caspases or metalloproteases can either enhance or dampen signaling. Crosstalk with survival pathways, including PI3K/AKT and NF-kB, provides additional layers of regulation. For example, AKT-mediated phosphorylation can inhibit pro-apoptotic proteins, and positive regulators of GO:2001241 may counteract this inhibition.
positive regulation of extrinsic apoptotic signaling pathway in absence of ligand and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| DCC | Colorectal cancer, congenital mirror movements | DCC knockout HCT116 cells; apoptosis assay |
| UNC5C | Colorectal cancer, neurodegeneration | UNC5C point mutation knock-in in neuronal cells |
| p75NTR | Alzheimer's disease, motor neuron disease | p75NTR overexpression in SH-SY5Y cells |
| CASP8 | Cancer, immunodeficiency | CASP8 knockout Jurkat cells; apoptosis induction |
| AKT1 | Cancer, survival signaling | AKT1 overexpression in dependence receptor-positive cells |
Cancer
Loss of dependence receptor signaling, which positively regulates apoptosis in the absence of ligands, is a common event in cancer. For instance, DCC and UNC5C are frequently downregulated or mutated in colorectal cancer, leading to reduced apoptosis and enhanced tumor growth. Positive regulators of this pathway may act as tumor suppressors, and their inactivation can contribute to oncogenesis.
Neurodegeneration
In neurodegenerative diseases, excessive apoptosis mediated by dependence receptors can lead to neuronal loss. For example, p75NTR signaling in the absence of neurotrophins contributes to motor neuron degeneration. Positive regulation of this pathway may exacerbate neuronal death, making it a target for neuroprotective strategies.
Developmental disorders
Dependence receptor signaling is critical for proper development, and its dysregulation can cause developmental disorders. For example, mutations in DCC are associated with congenital mirror movements and agenesis of the corpus callosum. Positive regulators of this pathway ensure appropriate apoptosis during development, and their disruption can lead to structural abnormalities.
From positive regulation of extrinsic apoptotic signaling pathway in absence of ligand-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of DCC enhance tumor growth? | DCC knockout in colorectal cancer cell lines (e.g., HCT116) |
| Does a UNC5C mutation affect ligand-independent apoptosis? | UNC5C point mutation knock-in in neuronal cells |
| Can overexpression of p75NTR induce apoptosis in absence of neurotrophins? | p75NTR overexpression in SH-SY5Y neuroblastoma cells |
| What is the role of caspase-8 in dependence receptor signaling? | CASP8 knockout in Jurkat cells followed by apoptosis assay |
| Does AKT1 modulate dependence receptor-induced apoptosis? | AKT1 overexpression or knockout in dependence receptor-positive cells |
| Can CRISPR library screening identify novel regulators of GO:2001241? | Genome-wide CRISPR knockout library in cells with inducible dependence receptor |
How to Study the positive regulation of extrinsic apoptotic signaling pathway in absence of ligand Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Annexin V/PI flow cytometry | Phosphatidylserine externalization and membrane integrity | Quantify apoptosis in dependence receptor models |
| Caspase-3/7 activity assay | Caspase enzymatic activity | Measure effector caspase activation |
| RNA-seq | Global gene expression changes | Identify transcriptional regulators of GO:2001241 |
| Mass spectrometry proteomics | Protein abundance and post-translational modifications | Discover novel interacting partners |
| Live-cell imaging | Real-time protein localization and interactions | Visualize receptor complex assembly |
| Luciferase reporter assay | Transcriptional activity of target promoters | Assess pro-apoptotic gene expression |
| CRISPR knockout library screen | Gene essentiality and pathway regulation | Identify positive regulators of apoptosis |
| TUNEL assay | DNA fragmentation | Detect apoptotic cells in tissue sections |
Apoptosis assays
Apoptosis can be measured by flow cytometry using Annexin V/propidium iodide staining, caspase activity assays, or TUNEL staining. These methods quantify the frequency of apoptotic cells and are essential for assessing positive regulation of the absence-of-ligand pathway.
Transcriptomics and proteomics
RNA sequencing and mass spectrometry-based proteomics can identify genes and proteins whose expression or modification changes during dependence receptor signaling. These approaches reveal positive regulators and downstream effectors.
Imaging and reporter assays
Live-cell imaging with fluorescently tagged proteins can visualize receptor complex formation and caspase activation in real time. Luciferase reporter assays can monitor transcriptional activity of pro-apoptotic genes.
CRISPR screening
Genome-wide CRISPR knockout or activation screens can identify genes that positively regulate the absence-of-ligand apoptotic pathway. These screens are powerful for discovering novel regulators and therapeutic targets.
How CRISPR Can Be Used to Study GO:2001241 positive regulation of extrinsic apoptotic signaling pathway in absence of ligand
Knockout
CRISPR knockout of dependence receptors (e.g., DCC, UNC5C) or downstream effectors (e.g., CASP8) can abolish the absence-of-ligand apoptotic pathway, confirming their essential role. Knockout cell lines are valuable for dissecting positive regulators by comparing apoptosis levels to wild-type cells.
Point Mutation
Introducing point mutations in dependence receptors (e.g., UNC5C) can mimic disease-associated variants and reveal how specific residues affect ligand-independent apoptosis. Point mutation knock-in models help link genotype to phenotype.
Knock-in
Knock-in of tagged versions of receptors or adaptors (e.g., GFP-DCC) allows visualization and immunoprecipitation of signaling complexes. Knock-in of disease mutations can create isogenic models for drug testing.
Overexpression
Overexpression of dependence receptors or positive regulators (e.g., p75NTR, DRAL) can sensitize cells to apoptosis in the absence of ligands. Overexpression models are useful for gain-of-function studies and for identifying downstream effects.
How EDITGENE Supports positive regulation of extrinsic apoptotic signaling pathway in absence of ligand Research
Researchers studying positive regulation of extrinsic apoptotic signaling pathway in absence of ligand-related genes often need to determine whether a candidate gene is causally involved in the pathway or merely correlated with apoptosis. EDITGENE provides a comprehensive suite of CRISPR-based services to enable such causal studies, from gene knockout to precise point mutations and library screens.
Contact EDITGENE today to design your custom CRISPR model for positive regulation of extrinsic apoptotic signaling pathway in absence of ligand research.
Frequently Asked Questions About positive regulation of extrinsic apoptotic signaling pathway in absence of ligand
What is GO:2001241?
GO:2001241 is a Gene Ontology biological_process term defined as any process that activates or increases the frequency, rate or extent of the extrinsic apoptotic signaling pathway in absence of ligand.
What genes are involved in positive regulation of extrinsic apoptotic signaling pathway in absence of ligand?
Key genes include dependence receptors such as DCC, UNC5 family members, and p75NTR, as well as downstream effectors like caspase-8, caspase-3, and adaptor proteins.
What is the role of dependence receptors in apoptosis?
Dependence receptors induce apoptosis when their ligands are absent, and positive regulation of this pathway enhances their pro-apoptotic signaling.
How is GO:2001241 related to cancer?
Loss of dependence receptor signaling can promote tumorigenesis by reducing apoptosis, making positive regulators potential tumor suppressors.
What experimental models are used to study GO:2001241?
Common models include CRISPR knockout, point mutation, knock-in, and overexpression cell lines, combined with apoptosis assays and omics analyses.
What is the difference between extrinsic and intrinsic apoptosis?
Extrinsic apoptosis is triggered by death receptors, while intrinsic apoptosis involves mitochondrial permeabilization; GO:2001241 specifically regulates the extrinsic pathway in the absence of ligand.
How can CRISPR be used to study positive regulation of extrinsic apoptotic signaling pathway in absence of ligand?
CRISPR can knockout, mutate, or overexpress genes to test their causal role in the pathway, and library screens can identify novel regulators.
What diseases are associated with dysregulation of GO:2001241?
Cancer, neurodegeneration, and developmental disorders have been linked to altered dependence receptor signaling.
What are the synonyms for GO:2001241?
Synonyms include positive regulation of dependence receptor signaling pathway, positive regulation of extrinsic apoptosis in absence of ligand, and positive regulation of extrinsic apoptotic signalling pathway in absence of ligand.
How can EDITGENE help with my research on GO:2001241?
EDITGENE provides CRISPR knockout, point mutation, knock-in, overexpression, library screening, and bioinformatics services to dissect the pathway.
Conclusion
GO:2001241, positive regulation of extrinsic apoptotic signaling pathway in absence of ligand, is a critical biological process that governs cell death when dependence receptors are unoccupied. Its dysregulation is implicated in cancer, neurodegeneration, and developmental disorders, making it a key area of research. CRISPR-based models and EDITGENE services can accelerate the discovery of positive regulators and therapeutic targets.
References
- 1. Li P et al.. 2021. Exploring the Pharmacological Mechanism of Radix Salvia Miltiorrhizae in the Treatment of Radiation Pneumonia by Using Network Pharmacology.. Front Oncol 11:684315 PMID: 34395252
