GO:0001906 cell killing: Mechanism, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0001906 cell killing describes any process in which one cell induces death in another cell or in its own kind, distinct from cell-autonomous death due to internal or environmental triggers.
• Cell killing is a fundamental biological process in immunity, development, microbial competition, and cancer therapy.
• Key effectors include caspases, pore-forming proteins, and metabolic enzymes that convert prodrugs into toxic metabolites.
• Experimental models range from bacterial spore killing assays to reconstituted caspase systems and lymphokine-activated killer cell assays.
• Dysregulation of cell killing contributes to cancer, autoimmune disease, and persistent infections.
• CRISPR-based knockout, knock-in, and overexpression models enable causal dissection of cell killing pathways in relevant cell types.
Description
Cell killing (GO:0001906) is a biological process in which one cell induces the death of another cell or of its own kind, as opposed to cell-autonomous death triggered by internal or environmental conditions. This term captures active killing mechanisms, including immune-mediated cytotoxicity, bacterial antagonism, and developmental programmed cell death. Understanding cell killing is essential because it underlies host defense, tissue homeostasis, and the efficacy of anticancer therapies.
cell killing At A Glance
| GO ID | GO:0001906 |
|---|---|
| GO term | cell killing |
| Ontology | biological_process |
| Synonym | necrosis |
| Major function | Induction of cell death by another cell, including immune cytotoxicity, bacterial antagonism, and developmental cell elimination |
| Related processes | Apoptosis, pyroptosis, necroptosis, phagocytosis, immune evasion |
| Taxonomic range | Bacteria, fungi, plants, animals |
| Experimental evidence | Reconstituted caspases, bacterial killing assays, lymphokine-activated killer cells, bystander killing |
What Is GO:0001906?
According to the Gene Ontology, GO:0001906 cell killing refers to any process in an organism that results in the killing of its own cells or those of another organism, including in some cases the death of the other organism. Killing here refers to the induction of death in one cell by another cell, not cell-autonomous death due to internal or other environmental conditions.
Why Is cell killing Important in Cell Biology?
Cell killing is central to immunity, development, and microbial competition, and its dysregulation contributes to cancer, autoimmunity, and infectious disease. Therapeutic strategies often aim to harness or inhibit cell killing, making it a high-value target for drug discovery and CRISPR-based functional genomics.
• Mediates immune surveillance and elimination of infected or transformed cells.
• Enables bacterial competition and niche exclusion, as shown for Serratia marcescens killing of fungal hyphae.
• Underlies developmental processes such as infanticide and maternal care circuits in mice.
• Contributes to cancer therapy by inducing tumor cell death.
• Involved in bystander killing effects that can amplify prodrug activation therapies.
• Provides a mechanism for targeted cell ablation in research using reconstituted caspases.
• Relevant to spore resistance and killing by radiation, heat, and chemicals.
• Dysregulation can lead to autoimmune diseases and chronic infections.
• Serves as a model for studying cell-cell contact-independent killing.
• Offers targets for CRISPR screening to identify novel killing effectors.
What Happens During cell killing?
Recognition and targeting
In simple terms: The killer cell identifies its target.
Killing often begins with recognition of the target cell via cell-surface molecules or secreted factors. In lymphokine-activated killer cells, killing of glioblastoma cell lines can occur independently of cell-cell adhesion, indicating that soluble mediators may initiate the process. Similarly, bacterial killing of fungal hyphae involves attachment and migration along the hyphae before induction of death.
Delivery of killing effectors
In simple terms: The killer cell delivers toxic molecules to the target.
Effector molecules such as caspases, pore-forming proteins, or metabolic enzymes are delivered to the target cell. Reconstituted caspases can be targeted to specific cells to induce killing. In bystander killing, Escherichia coli purine nucleoside phosphorylase converts a prodrug into a toxic metabolite that kills neighboring cells without requiring cell-to-cell contact.
Induction of death pathways
In simple terms: The target cell's death machinery is activated.
Once effectors are delivered, they activate death pathways in the target cell. This may involve caspase activation, mitochondrial outer membrane permeabilization, or other death programs. Cancer cells often exhibit blocks in apoptosis that can be diagnosed and exploited therapeutically.
Execution and clearance
In simple terms: The target cell dies and is removed.
The target cell undergoes death, and the corpse is cleared by phagocytes or other mechanisms. In some cases, the death of the killer cell itself may occur, as seen in infanticide circuits where specific neurons are eliminated. Spore killing by radiation, heat, and chemicals also results in loss of viability.
Key Genes Involved in GO:0001906 cell killing
The following genes and proteins are experimentally implicated in cell killing processes, based on the verified literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| CASP3 | Executioner caspase in apoptosis | Targeted cell killing by reconstituted caspases |
| CASP7 | Effector caspase | Reconstituted caspase systems |
| PNP | Purine nucleoside phosphorylase | Bystander cell killing via prodrug activation |
| FAS | Death receptor | Apoptosis induction in cancer |
| FASLG | Fas ligand | Immune-mediated killing |
| PRF1 | Perforin | Pore formation in target cells |
| GZMB | Granzyme B | Serine protease that activates caspases |
| TNF | Tumor necrosis factor | Inflammatory cell killing |
| TRAIL | TNF-related apoptosis-inducing ligand | Selective killing of tumor cells |
| BAX | Pro-apoptotic Bcl-2 family member | Mitochondrial apoptosis |
| BAK | Pro-apoptotic Bcl-2 family member | Mitochondrial apoptosis |
| BCL2 | Anti-apoptotic protein | Blocks apoptosis in cancer |
| MCL1 | Anti-apoptotic protein | Apoptosis regulation |
| CASP8 | Initiator caspase | Death receptor signaling |
| CASP9 | Initiator caspase | Mitochondrial apoptosis |
| CYCS | Cytochrome c | Apoptosome formation |
| APAF1 | Apoptosome scaffold | Caspase activation |
| DIABLO | IAP antagonist | Apoptosis promotion |
How Is cell killing Regulated?
Cell killing is tightly regulated by pro- and anti-apoptotic proteins, including Bcl-2 family members and inhibitors of apoptosis (IAPs). In immune cells, killing activity is modulated by cytokines such as IL-2, which activates lymphokine-activated killer cells. Bacterial killing of fungi is regulated by attachment and migration along hyphae. Spore killing by radiation, heat, and chemicals depends on spore resistance mechanisms.
cell killing and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| BCL2 | Cancer (apoptosis evasion) | Knockout or overexpression in cancer cell lines |
| CASP3 | Cancer, neurodegeneration | Point mutation to disable catalytic activity |
| PNP | Cancer (prodrug activation) | Knock-in of PNP in tumor cells for bystander killing |
| PRF1 | Immune deficiency | Knockout in cytotoxic lymphocytes |
| FAS | Autoimmune lymphoproliferative syndrome | Knock-in of patient mutations |
Cancer
Cancer cells often evade cell killing by upregulating anti-apoptotic proteins such as BCL2 and MCL1, leading to blocks in apoptosis. Therapies that mimic BH3-only proteins can overcome these blocks and induce tumor cell death.
Infectious disease
Bacterial pathogens like Serratia marcescens can kill fungal hyphae, which may influence microbial communities and infection outcomes. Understanding these killing mechanisms could inform new antimicrobial strategies.
Neurological and behavioral disorders
Infanticide and maternal care circuits in mice involve targeted cell killing of specific neurons, linking cell killing to behavioral regulation. Dysregulation may contribute to psychiatric conditions.
From cell killing-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does gene X induce cell killing? | CRISPR knockout in target cells followed by co-culture with killer cells |
| Is catalytic activity required for killing? | Point mutation of catalytic residues |
| Can a prodrug convert to a killer metabolite? | Knock-in of PNP and prodrug treatment |
| Does overexpression enhance killing? | Overexpression of candidate gene in target cells |
| What is the subcellular localization of killing effectors? | Tagged knock-in with fluorescent protein |
| Can we screen for novel killing genes? | CRISPR library screening in co-culture systems |
How to Study the cell killing Process
| Method | What It Measures | Typical Application |
|---|---|---|
| MTT assay | Metabolic activity | Quantify cell killing |
| Annexin V/PI flow cytometry | Apoptosis and necrosis | Detect cell death |
| Caspase-3 activity assay | Caspase activation | Confirm apoptotic killing |
| Transwell co-culture | Contact-independent killing | Bystander killing |
| CFU counting | Bacterial/fungal viability | Microbial killing |
| CRISPR knockout screen | Gene essentiality for killing | Identify novel effectors |
| Live-cell imaging | Kinetics of killing | Real-time monitoring |
Cell viability assays
Cell killing is quantified using viability assays such as MTT, ATP luminescence, or flow cytometry with Annexin V/PI staining. These methods measure the loss of membrane integrity and metabolic activity in target cells.
Co-culture and killing assays
Killer and target cells are co-cultured, and target cell death is measured. For contact-independent killing, transwell systems are used. Bacterial killing of fungi is assessed by microscopy and CFU counts.
Caspase activity assays
Caspase activation is measured using fluorogenic substrates or western blotting for cleaved caspases. Reconstituted caspase systems allow precise control of activation.
CRISPR screening
Genome-wide CRISPR knockout or activation screens can identify genes that regulate susceptibility or resistance to cell killing. Libraries targeting kinases, apoptotic regulators, or immune effectors are commonly used.
How CRISPR Can Be Used to Study GO:0001906 cell killing
Knockout
CRISPR knockout of candidate genes in target or killer cells can determine whether a gene is required for cell killing. For example, knocking out CASP3 in target cells blocks apoptosis induced by reconstituted caspases.
Point Mutation
Point mutations can dissect catalytic activity or interaction domains. Mutating the catalytic cysteine of caspases abolishes killing activity.
Knock-in
Knock-in of reporter tags or disease alleles allows tracking of killing effectors and modeling of patient mutations. Tagged caspases enable visualization of their localization during killing.
Overexpression
Overexpression of pro-apoptotic genes such as BAX or PNP can sensitize cells to killing or enable bystander killing.
How EDITGENE Supports cell killing Research
Researchers studying cell killing-related genes often need to determine whether a candidate gene is causally involved in inducing or resisting cell death. EDITGENE provides comprehensive CRISPR services to generate precisely engineered cell models for such functional studies.
Contact EDITGENE today to design your custom CRISPR model for cell killing research.
Frequently Asked Questions About cell killing
What is GO:0001906 cell killing?
GO:0001906 cell killing is a biological process in which one cell induces the death of another cell or its own kind, as defined by the Gene Ontology.
What genes are involved in cell killing?
Key genes include CASP3, CASP7, PNP, FAS, FASLG, PRF1, GZMB, and BCL2 family members, among others.
How is cell killing different from apoptosis?
Apoptosis is a form of cell-autonomous death, while cell killing specifically refers to death induced by another cell.
What are examples of cell killing in bacteria?
Serratia marcescens can kill fungal hyphae through attachment and migration.
Can cell killing occur without cell-to-cell contact?
Yes, bystander cell killing by Escherichia coli purine nucleoside phosphorylase does not require cell-to-cell contact.
What diseases are associated with defective cell killing?
Cancer, autoimmune diseases, and infections are linked to dysregulated cell killing.
How can I study cell killing in the lab?
Common methods include co-culture assays, caspase activity assays, and CRISPR screens.
What is the role of caspases in cell killing?
Caspases are executioner proteases that induce cell death; reconstituted caspases can target specific cells for killing.
What is lymphokine-activated killer cell killing?
LAK cells can kill glioblastoma cell lines independently of cell-cell adhesion.
How does CRISPR help study cell killing?
CRISPR knockout, knock-in, and overexpression models allow causal testing of genes in cell killing pathways.
Conclusion
GO:0001906 cell killing is a critical biological process with broad relevance to immunity, development, and disease. Understanding its molecular mechanisms and regulation offers opportunities for therapeutic intervention. EDITGENE provides the CRISPR tools and services to accelerate research in this field.
References
- 1. Setlow P. 2006. Spores of Bacillus subtilis: their resistance to and killing by radiation, heat and chemicals.. J Appl Microbiol 101(3):514-25 PMID: 16907802
- 2. Mei L et al.. 2023. Antagonistic circuits mediating infanticide and maternal care in female mice.. Nature 618(7967):1006-1016 PMID: 37286598
- 3. Letai AG. 2008. Diagnosing and exploiting cancer's addiction to blocks in apoptosis.. Nat Rev Cancer 8(2):121-32 PMID: 18202696
- 4. Hover T et al.. 2016. Mechanisms of Bacterial (Serratia marcescens) Attachment to, Migration along, and Killing of Fungal Hyphae.. Appl Environ Microbiol 82(9):2585-94 PMID: 26896140
- 5. Komatsu F et al.. 2000. Cell-cell adhesion-independent killing due to lymphokine-activated killer cells against glioblastoma cell lines.. Oncol Res 12(9-10):371-81 PMID: 11697816
- 7. Chelur DS et al.. 2007. Targeted cell killing by reconstituted caspases.. Proc Natl Acad Sci U S A 104(7):2283-8 PMID: 17283333
- 8. Hughes BW et al.. 1998. Cell to cell contact is not required for bystander cell killing by Escherichia coli purine nucleoside phosphorylase.. J Biol Chem 273(4):2322-8 PMID: 9442077
