GO:1901030 positive regulation of mitochondrial outer membrane permeabilization involved in apoptotic signaling pathway: Apoptosis Regulation, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:1901030 describes the biological process that activates or increases the frequency, rate or extent of mitochondrial outer membrane permeabilization (MOMP) during apoptotic signaling.
• MOMP is a decisive step in the intrinsic apoptosis pathway, releasing cytochrome c and other intermembrane space proteins that activate caspases.
• The BCL-2 family of proteins, including BAX, BAK, BID, and anti-apoptotic members such as BCL-2 and BCL-xL, directly controls MOMP.
• Positive regulation of MOMP is essential for granzyme B-mediated apoptosis, where Bid cleavage by granzyme B amplifies the mitochondrial death signal.
• Dysregulation of MOMP contributes to cancer chemoresistance and neurodegenerative disorders, making it a therapeutic target.
• CRISPR-based knockout, knock-in, and overexpression models enable precise dissection of genes that positively regulate MOMP.
Description
Mitochondrial outer membrane permeabilization (MOMP) is a critical event in the intrinsic apoptotic signaling pathway, leading to the release of pro-apoptotic factors such as cytochrome c and Smac/DIABLO from the mitochondrial intermembrane space. The positive regulation of MOMP, annotated as GO:1901030, encompasses any process that activates or increases the frequency, rate or extent of MOMP involved in apoptotic signaling. This regulatory process is essential for proper cell death execution and is tightly controlled by the BCL-2 family of proteins. Researchers study GO:1901030 to understand how cells commit to apoptosis, how cancer cells evade death, and how to design targeted therapies that restore or inhibit MOMP. Experimental evidence from functional genomics screens has identified novel regulators of MOMP, such as PCAF and ADA3, which influence granzyme B-mediated apoptosis and Bid cleavage. Additionally, intramitochondrial recruitment of endolysosomes and XIAP-mediated Smac degradation represent mechanisms that antagonize MOMP, highlighting the complexity of its regulation. Understanding the positive regulation of MOMP is therefore central to both basic apoptosis research and translational oncology.
positive regulation of mitochondrial outer membrane permeabilization involved in apoptotic signaling pathway At A Glance
| GO ID | GO:1901030 |
|---|---|
| GO term | positive regulation of mitochondrial outer membrane permeabilization involved in apoptotic signaling pathway |
| Ontology | biological_process |
| Synonym | activation of MOMP; positive regulation of MOMP; upregulation of MOMP |
| Major function | Promotes mitochondrial outer membrane permeabilization during apoptosis |
| Parent term | positive regulation of mitochondrial outer membrane permeabilization |
| Related pathway | Intrinsic apoptotic signaling pathway |
| Key regulators | BCL-2 family proteins (BAX, BAK, BID, BCL-2, BCL-xL) |
What Is GO:1901030?
GO:1901030 is a Gene Ontology biological process term defined as any process that activates or increases the frequency, rate or extent of mitochondrial outer membrane permeabilization involved in apoptotic signaling pathway. In simpler terms, it covers all molecular events that promote the formation of pores in the mitochondrial outer membrane, a step that commits a cell to apoptosis. This term is a child of positive regulation of mitochondrial outer membrane permeabilization and is part of the apoptotic signaling pathway.
Why Is positive regulation of mitochondrial outer membrane permeabilization involved in apoptotic signaling pathway Important in Cell Biology?
The positive regulation of MOMP is a point of no return in apoptosis, determining whether a cell survives or dies. Its dysregulation is implicated in cancer, where overexpression of anti-apoptotic BCL-2 proteins blocks MOMP and confers chemoresistance. Conversely, excessive MOMP contributes to neurodegeneration and ischemia-reperfusion injury. Understanding the positive regulators of MOMP provides opportunities for therapeutic intervention, such as BH3 mimetics that activate MOMP in cancer cells.
• MOMP is the decisive step for cytochrome c release and caspase activation in intrinsic apoptosis.
• Positive regulators of MOMP include pro-apoptotic BCL-2 family members BAX, BAK, and BID.
• Granzyme B-mediated apoptosis requires Bid cleavage and MOMP amplification.
• XIAP can antagonize MOMP by promoting Smac degradation via endolysosomal recruitment.
• Cancer cells often evade apoptosis by upregulating anti-apoptotic BCL-2 proteins, blocking MOMP.
• Functional genomics screens have identified PCAF and ADA3 as regulators of Bid cleavage and MOMP.
• MOMP is a target for BH3 mimetic drugs in cancer therapy.
• Anastatic cancer cells show altered nuclear export pathways that may influence MOMP regulators.
• Protein-protein interaction networks link MOMP regulators to breast and colon cancer.
• CRISPR screens can uncover novel positive regulators of MOMP for drug discovery.
What Happens During positive regulation of mitochondrial outer membrane permeabilization involved in apoptotic signaling pathway?
Activation of BH3-only proteins
In simple terms: BH3-only proteins are the triggers that start the mitochondrial death process.
In response to apoptotic stimuli, BH3-only proteins such as BID, BIM, and PUMA are activated. For example, granzyme B cleaves Bid to generate truncated Bid (tBid), which translocates to mitochondria to promote MOMP. This step is a key positive regulatory event in the apoptotic signaling pathway.
BAX/BAK oligomerization and pore formation
In simple terms: BAX and BAK punch holes in the mitochondrial outer membrane.
Activated BAX and BAK undergo conformational changes, oligomerize, and insert into the mitochondrial outer membrane, forming pores that permit the release of cytochrome c and other pro-apoptotic factors. This is the execution phase of MOMP and is directly promoted by positive regulators.
Release of intermembrane space proteins
In simple terms: Pro-apoptotic proteins escape from mitochondria to activate caspases.
Upon MOMP, cytochrome c, Smac/DIABLO, and other proteins are released into the cytosol. Cytochrome c binds APAF-1 to form the apoptosome, activating caspase-9, while Smac neutralizes XIAP. However, XIAP can promote Smac degradation via endolysosomal recruitment, antagonizing MOMP.
Amplification and regulation by BCL-2 family
In simple terms: Anti-apoptotic proteins put brakes on MOMP, while pro-apoptotic ones push it forward.
Anti-apoptotic BCL-2 proteins (BCL-2, BCL-xL, MCL-1) inhibit BAX/BAK, whereas BH3-only proteins neutralize these inhibitors. The balance determines the threshold for MOMP. Positive regulation of MOMP occurs when pro-apoptotic signals overwhelm anti-apoptotic defenses.
Crosstalk with other pathways
In simple terms: Other cellular processes can influence MOMP.
Functional genomics screens have identified PCAF and ADA3 as regulators of granzyme B-mediated apoptosis and Bid cleavage, linking histone acetylation to MOMP regulation. Additionally, nuclear export pathways may affect the localization of MOMP regulators in anastatic cancer cells.
Key Genes Involved in GO:1901030 positive regulation of mitochondrial outer membrane permeabilization involved in apoptotic signaling pathway
The following genes and proteins are key players in the positive regulation of mitochondrial outer membrane permeabilization involved in apoptotic signaling pathway.
| Gene | Major Role | Research Relevance |
|---|---|---|
| BAX | Pro-apoptotic effector, forms pores in mitochondrial outer membrane | Knockout models show resistance to apoptosis; target for cancer therapy |
| BAK | Pro-apoptotic effector, oligomerizes with BAX to permeabilize mitochondria | BAK knockout cells are defective in MOMP |
| BID | BH3-only protein, cleaved by granzyme B to tBid, activates BAX/BAK | Bid cleavage is a key step in granzyme B-mediated apoptosis |
| BCL-2 | Anti-apoptotic, inhibits BAX/BAK | Overexpression blocks MOMP and confers chemoresistance |
| BCL-xL | Anti-apoptotic, binds and inhibits BH3-only proteins | Target for BH3 mimetics |
| MCL-1 | Anti-apoptotic, sequesters BAK | MCL-1 inhibitors promote MOMP in cancer |
| PUMA | BH3-only protein, activates BAX/BAK | PUMA induction triggers MOMP |
| BIM | BH3-only protein, neutralizes anti-apoptotic BCL-2 proteins | BIM is a positive regulator of MOMP |
| tBID | Truncated BID, directly activates BAX/BAK | Generated by granzyme B or caspase-8 |
| XIAP | E3 ligase, promotes Smac degradation, antagonizes MOMP | XIAP inhibitors sensitize cells to MOMP |
| Smac/DIABLO | Released upon MOMP, neutralizes XIAP | Smac mimetics promote apoptosis |
| PCAF | Histone acetyltransferase, regulates Bid cleavage | Identified in functional genomics screen for granzyme B apoptosis |
| ADA3 | Adaptor protein, regulates Bid cleavage | Identified in functional genomics screen |
| APAF-1 | Forms apoptosome with cytochrome c, activates caspase-9 | Downstream of MOMP |
| Caspase-9 | Initiator caspase activated by apoptosome | Execution of apoptosis after MOMP |
| Caspase-3 | Effector caspase, cleaves cellular substrates | Final step of apoptosis |
| Cytochrome c | Released from mitochondria upon MOMP, activates apoptosome | Marker of MOMP |
How Is positive regulation of mitochondrial outer membrane permeabilization involved in apoptotic signaling pathway Regulated?
The positive regulation of MOMP is controlled by the balance between pro-apoptotic and anti-apoptotic BCL-2 family proteins. Upstream signals such as DNA damage, growth factor withdrawal, and granzyme B activate BH3-only proteins, which in turn activate BAX/BAK or neutralize anti-apoptotic proteins. Additionally, XIAP-mediated degradation of Smac via endolysosomal recruitment can antagonize MOMP, providing a layer of negative regulation. Post-translational modifications, including phosphorylation and acetylation, also modulate the activity of MOMP regulators.
positive regulation of mitochondrial outer membrane permeabilization involved in apoptotic signaling pathway and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| BCL-2 | Cancer chemoresistance | Overexpression in cancer cell lines to block MOMP |
| BAX | Cancer, apoptosis evasion | Knockout in cancer cells to assess MOMP |
| BID | Granzyme B-mediated apoptosis | Knockout in Jurkat cells to study Bid cleavage |
| XIAP | Cancer, apoptosis resistance | Knockout or overexpression to modulate Smac degradation |
| PCAF | Granzyme B apoptosis | Knockout in K562 cells to study Bid cleavage |
Cancer
Cancer cells frequently overexpress anti-apoptotic BCL-2 proteins, such as BCL-2 or BCL-xL, which block MOMP and confer resistance to chemotherapy. Conversely, defects in positive regulators of MOMP, like BAX mutations, are found in certain cancers. BH3 mimetics that mimic pro-apoptotic BH3-only proteins can restore MOMP and induce apoptosis in cancer cells. Protein-protein interaction networks have linked MOMP regulators to breast and colon cancer.
Neurodegeneration
Excessive MOMP contributes to neuronal loss in neurodegenerative diseases such as Alzheimer's and Parkinson's. Although direct evidence from the provided citations is limited, the general role of MOMP in apoptosis suggests that inhibiting positive regulators of MOMP could be neuroprotective.
Anastatic cancer
Anastatic cancer cells, which survive after apoptosis induction, show altered nuclear export pathways that may affect the localization of MOMP regulators. This suggests that positive regulation of MOMP could be modulated in these persistent cells.
From positive regulation of mitochondrial outer membrane permeabilization involved in apoptotic signaling pathway-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does gene X positively regulate MOMP? | CRISPR knockout of gene X followed by MOMP assays |
| Does a point mutation in BAX affect MOMP? | CRISPR point mutation knock-in of BAX mutant |
| Can a tagged BAX be used to track MOMP? | Knock-in of fluorescent tag on BAX |
| Does overexpression of BCL-2 block MOMP? | Overexpression of BCL-2 in cancer cells |
| What genes regulate granzyme B-mediated MOMP? | Genome-wide CRISPR library screening |
| How does XIAP antagonize MOMP? | Knockout of XIAP and assess Smac levels |
How to Study the positive regulation of mitochondrial outer membrane permeabilization involved in apoptotic signaling pathway Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Flow cytometry with TMRE | Mitochondrial membrane potential | Quantify MOMP in cells |
| Immunofluorescence for cytochrome c | Cytochrome c release | Detect MOMP activation |
| CRISPR knockout screen | Genes required for MOMP | Identify positive regulators |
| Co-immunoprecipitation | Protein-protein interactions | Study BCL-2 family complexes |
| Live-cell imaging | Real-time MOMP dynamics | Visualize BAX activation |
| Western blot for tBid | Bid cleavage | Assess granzyme B pathway |
| Smac degradation assay | Smac protein levels | Study XIAP-mediated antagonism |
Measuring MOMP
MOMP is commonly measured by flow cytometry using dyes that detect mitochondrial membrane potential (e.g., TMRE) or by immunofluorescence for cytochrome c release. These methods quantify the extent of permeabilization.
Functional genomics screens
CRISPR-based knockout screens can identify positive regulators of MOMP. For example, a screen identified PCAF and ADA3 as regulators of granzyme B-mediated apoptosis and Bid cleavage.
Protein interaction studies
Co-immunoprecipitation and proximity ligation assays can reveal interactions among BCL-2 family proteins during MOMP. Protein-protein interaction networks have been used to link MOMP regulators to cancer.
Live-cell imaging
Live-cell imaging with fluorescently tagged BAX or cytochrome c allows real-time visualization of MOMP dynamics. This method is useful for studying the kinetics of positive regulation.
How CRISPR Can Be Used to Study GO:1901030 positive regulation of mitochondrial outer membrane permeabilization involved in apoptotic signaling pathway
Knockout
CRISPR knockout of candidate genes can determine whether they are required for positive regulation of MOMP. For example, knocking out PCAF or ADA3 reduced Bid cleavage and apoptosis in a functional genomics screen. Knockout of BAX or BAK abolishes MOMP.
Point Mutation
Point mutations can be introduced to study specific residues in MOMP regulators. For instance, mutation of phosphorylation sites in BCL-2 family proteins can reveal their role in modulating MOMP. CRISPR base editing enables precise point mutations without double-strand breaks.
Knock-in
Knock-in of fluorescent tags or epitope tags allows tracking of MOMP regulators. Tagging endogenous BAX with a fluorescent protein enables live-cell imaging of its activation and pore formation. Knock-in of disease-associated mutations can model their impact on MOMP.
Overexpression
Overexpression of anti-apoptotic proteins like BCL-2 blocks MOMP and confers resistance to apoptosis. Conversely, overexpression of pro-apoptotic BH3-only proteins promotes MOMP. CRISPR activation (CRISPRa) can be used for controlled overexpression.
How EDITGENE Supports positive regulation of mitochondrial outer membrane permeabilization involved in apoptotic signaling pathway Research
Researchers studying positive regulation of mitochondrial outer membrane permeabilization involved in apoptotic signaling pathway-related genes often need to determine whether a candidate gene is causally involved in MOMP regulation or is merely a bystander. EDITGENE provides comprehensive CRISPR services to enable such functional studies.
Contact EDITGENE today to design your custom CRISPR model for positive regulation of mitochondrial outer membrane permeabilization involved in apoptotic signaling pathway research.
Frequently Asked Questions About positive regulation of mitochondrial outer membrane permeabilization involved in apoptotic signaling pathway
What is GO:1901030?
GO:1901030 is a Gene Ontology biological process term for any process that activates or increases the frequency, rate or extent of mitochondrial outer membrane permeabilization involved in apoptotic signaling pathway.
What genes are involved in positive regulation of MOMP?
Key genes include BAX, BAK, BID, BCL-2, BCL-xL, MCL-1, PUMA, BIM, and XIAP.
How is MOMP measured in the lab?
MOMP is measured by flow cytometry with TMRE, immunofluorescence for cytochrome c release, or live-cell imaging of BAX activation.
What is the role of BID in MOMP?
BID is cleaved by granzyme B to tBid, which translocates to mitochondria and activates BAX/BAK to promote MOMP.
How does XIAP regulate MOMP?
XIAP can promote Smac degradation via endolysosomal recruitment, thereby antagonizing MOMP.
What diseases are linked to MOMP dysregulation?
Cancer chemoresistance and neurodegeneration are associated with altered MOMP regulation.
Can CRISPR be used to study MOMP?
Yes, CRISPR knockout, knock-in, and overexpression models are widely used to dissect MOMP regulation.
What is the difference between MOMP and apoptosis?
MOMP is a specific step in the intrinsic apoptosis pathway, leading to cytochrome c release and caspase activation.
What are BH3 mimetics?
BH3 mimetics are drugs that mimic pro-apoptotic BH3-only proteins to activate MOMP in cancer cells.
How does granzyme B induce MOMP?
Granzyme B cleaves Bid to tBid, which activates BAX/BAK and induces MOMP.
Conclusion
The positive regulation of mitochondrial outer membrane permeabilization involved in apoptotic signaling pathway (GO:1901030) is a central process in apoptosis, controlled by the BCL-2 family and modulated by various cellular signals. Its dysregulation contributes to cancer and other diseases, making it a prime target for therapeutic intervention. CRISPR-based models and functional genomics screens continue to uncover new regulators, offering hope for novel treatments.
References
- 1. Seervi M et al.. 2019. Molecular profiling of anastatic cancer cells: potential role of the nuclear export pathway.. Cell Oncol (Dordr) 42(5):645-661 PMID: 31147963
- 2. Roy MJ et al.. 2014. Cell death and the mitochondria: therapeutic targeting of the BCL-2 family-driven pathway.. Br J Pharmacol 171(8):1973-87 PMID: 24117105
- 3. Zamanian-Azodi M et al.. 2015. Protein-Protein Interaction Network could reveal the relationship between the breast and colon cancer.. Gastroenterol Hepatol Bed Bench 8(3):215-24 PMID: 26328044
- 4. Hamacher-Brady A et al.. 2014. Intramitochondrial recruitment of endolysosomes mediates Smac degradation and constitutes a novel intrinsic apoptosis antagonizing function of XIAP E3 ligase.. Cell Death Differ 21(12):1862-76 PMID: 25080938
- 5. Brasacchio D et al.. 2014. A functional genomics screen identifies PCAF and ADA3 as regulators of human granzyme B-mediated apoptosis and Bid cleavage.. Cell Death Differ 21(5):748-60 PMID: 24464226
