GO:0140545 ATP-dependent protein disaggregase activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0140545 ATP-dependent protein disaggregase activity is a molecular_function defined as an ATP-dependent chaperone activity that solubilizes ordered protein aggregates.
• The reaction is driven by AAA+ ATPases such as Hsp104 in yeast and ClpG in bacteria, which thread polypeptide chains through a central pore to extract monomers from aggregates.
• In metazoa, disaggregation is performed by a collaborative network in which Hsp110 (Apg-2) synergizes with Hsp70 and Hsp40 to reactivate aggregated proteins.
• Small heat shock proteins (sHsps) act upstream by organizing aggregates into accessible conformations that disaggregases can process.
• Disaggregation is functionally coupled to protein quality control, including proteolytic clearance of intra-nuclear inclusions.
• Dysregulation of disaggregation is linked to neurodegeneration, cancer and other protein-misfolding diseases, making it a target for mechanistic and therapeutic studies.
Description
ATP-dependent protein disaggregase activity (GO:0140545) is a molecular_function that enables cells to rescue proteins trapped in ordered aggregates. The QuickGO definition states that it is an ATP-dependent molecular chaperone activity that mediates the solubilization of ordered protein aggregates. This activity is essential because aggregated proteins are not only inactive but can also be toxic, and their accumulation is a hallmark of many age-related and neurodegenerative disorders. Mechanistically, disaggregases belong to the AAA+ superfamily of ATPases and use the energy of ATP hydrolysis to extract polypeptides from aggregates, often in cooperation with Hsp70/Hsp40 systems. In bacteria and yeast, dedicated disaggregases such as ClpG and Hsp104 can directly bind and remodel aggregates. In metazoa, which lack a direct Hsp104 ortholog, disaggregation is achieved by a synergistic network of Hsp110, Hsp70 and Hsp40. Understanding GO:0140545 is therefore central to protein quality control, stress biology and the development of therapies for protein-misfolding diseases.
ATP-dependent protein disaggregase activity At A Glance
| GO ID | GO:0140545 |
|---|---|
| GO term | ATP-dependent protein disaggregase activity |
| Ontology | molecular_function |
| Synonym | protein disaggregase activity; protein unfoldase activity |
| Major function | ATP-dependent solubilization of ordered protein aggregates |
| Cellular context | Cytosol, nucleus, and other compartments where protein aggregates form |
| Representative proteins | Hsp104 (yeast), ClpG (bacteria), Hsp110/Hsp70/Hsp40 (metazoa) |
| Energy requirement | ATP binding and hydrolysis |
| Related processes | Protein quality control, stress response, proteostasis |
What Is GO:0140545?
In simple terms, ATP-dependent protein disaggregase activity is the cell's ability to use ATP to pull apart clumped proteins and make them soluble again. According to QuickGO, it is an ATP-dependent molecular chaperone activity that mediates the solubilization of ordered protein aggregates. This activity is distinct from general chaperone functions because it acts on already-formed aggregates rather than on nascent or partially folded polypeptides. It requires ATP binding and hydrolysis to drive conformational changes that thread substrate polypeptides through a central channel, thereby releasing them from the aggregate. The activity is often coupled to downstream refolding or degradation pathways.
Why Is ATP-dependent protein disaggregase activity Important in Cell Biology?
ATP-dependent protein disaggregase activity is a cornerstone of proteostasis because it reverses the accumulation of aggregated proteins that would otherwise impair cellular function. Without this activity, cells cannot efficiently clear aggregates formed during heat shock, oxidative stress or aging. The importance of GO:0140545 extends to human health: impaired disaggregation is associated with neurodegenerative diseases characterized by protein inclusions, and modulating disaggregase activity is being explored as a therapeutic strategy. Moreover, disaggregation is functionally linked to proteolytic clearance pathways, ensuring that irreversibly damaged proteins are removed.
• Maintains proteostasis by solubilizing aggregated proteins that arise during stress and aging.
• Prevents toxicity from protein aggregates in neurodegenerative diseases such as Alzheimer's and Parkinson's.
• Cooperates with Hsp70/Hsp40 systems to refold or degrade extracted polypeptides.
• Small heat shock proteins organize aggregates to facilitate disaggregase access.
• Disaggregation can trigger proteolytic clearance of intra-nuclear inclusions.
• Bacterial disaggregases like ClpG contribute to stress survival and virulence.
• Yeast Hsp104 is a model disaggregase whose mechanism informs metazoan biology.
• Disaggregase activity is a potential target for cancer and neurodegeneration therapies.
• Assays for disaggregation are used in drug discovery and mechanistic studies.
• Understanding GO:0140545 helps interpret gene ontology annotations in proteomics and genomics.
What Happens During ATP-dependent protein disaggregase activity?
Substrate recognition and aggregate binding
In simple terms: The disaggregase first grabs onto the clump of proteins.
Disaggregases such as ClpG and Hsp104 recognize and bind to exposed hydrophobic patches on aggregated polypeptides. Structural studies of ClpG reveal a dedicated aggregate-binding domain that interacts with the substrate and positions it for translocation. In yeast, the M-domain of Hsp104 controls protein remodeling activity in an Hsp70/Hsp40-dependent manner, indicating that substrate engagement is regulated by co-chaperones. Small heat shock proteins (sHsps) can also bind aggregates and organize them into conformations that are more accessible to disaggregases.
ATP-driven polypeptide threading
In simple terms: Using ATP as fuel, the machine pulls the protein chain through a narrow tunnel.
Once bound, AAA+ disaggregases use ATP hydrolysis to drive conformational changes that thread the polypeptide chain through a central pore. This threading action exerts a pulling force that extracts individual polypeptides from the aggregate. The energy from ATP is essential; without hydrolysis, the disaggregase cannot perform mechanical work. In metazoa, the Hsp110/Hsp70/Hsp40 system synergizes to catalyze protein disaggregation and reactivation in a cell-free system, demonstrating that ATP-dependent threading is conserved in principle.
Release and handover to folding or degradation
In simple terms: After extraction, the protein is either refolded or sent for destruction.
Following extraction, the released polypeptide can be refolded by the chaperone network or targeted for degradation. Chaperone-mediated protein disaggregation triggers proteolytic clearance of intra-nuclear protein inclusions, linking disaggregation to the ubiquitin-proteasome system. Hsp70 interacts with a network of co-chaperones and substrates to decide the fate of the extracted protein. This handover ensures that irreversibly damaged proteins do not re-aggregate.
Cooperation with small heat shock proteins
In simple terms: Small heat shock proteins act like organizers that make the clump easier to take apart.
Small heat shock proteins (sHsps) play a critical role in organizing cytosolic protein aggregation and disaggregation. They form dynamic oligomers that bind misfolded proteins and keep them in a disaggregation-competent state. By doing so, sHsps enhance the efficiency of ATP-dependent disaggregases and prevent the formation of large, irreversible aggregates. This cooperation is particularly important under stress conditions when aggregate load increases.
Key Genes Involved in GO:0140545 ATP-dependent protein disaggregase activity
The following genes and proteins are central to ATP-dependent protein disaggregase activity and its regulation.
| Gene | Major Role | Research Relevance |
|---|---|---|
| HSP104 | Yeast AAA+ disaggregase that solubilizes aggregates | Model for mechanistic studies of disaggregation |
| CLPG | Bacterial AAA+ disaggregase with aggregate-binding domain | Structural and functional studies of disaggregation |
| HSPA1A | Human Hsp70 that collaborates with Hsp110 and Hsp40 | Core component of metazoan disaggregation machinery |
| HSPA8 | Constitutively expressed Hsp70 involved in protein quality control | Chaperone network interactions |
| HSPH1 | Human Hsp110 that synergizes with Hsp70/Hsp40 | Disaggregation and reactivation in cell-free systems |
| DNAJB1 | Hsp40 co-chaperone that stimulates Hsp70 ATPase activity | Regulation of disaggregation |
| HSPB1 | Small heat shock protein that organizes aggregates | Aggregate organization and disaggregation |
| HSPB5 | Small heat shock protein involved in stress response | sHsp function in proteostasis |
| HSPB8 | sHsp linked to protein quality control | Disaggregation and disease models |
| CLPB | Mitochondrial AAA+ disaggregase | Mitochondrial proteostasis |
| CLPX | AAA+ unfoldase in mitochondria | Protein quality control |
| LONP1 | Mitochondrial protease with unfoldase activity | Degradation of aggregated proteins |
| VCP | AAA+ ATPase involved in protein degradation | Link between disaggregation and proteolysis |
| UBB | Ubiquitin involved in tagging proteins for degradation | Proteolytic clearance after disaggregation |
| SQSTM1 | Autophagy receptor that can clear aggregates | Alternative aggregate clearance pathways |
| HSF1 | Transcription factor regulating heat shock response | Upstream regulation of disaggregase expression |
| BAG3 | Co-chaperone that links Hsp70 to autophagy | Aggregate clearance and disease |
How Is ATP-dependent protein disaggregase activity Regulated?
ATP-dependent protein disaggregase activity is regulated at multiple levels. Transcriptionally, the heat shock response driven by HSF1 induces the expression of major chaperones including Hsp70, Hsp40 and sHsps, thereby increasing disaggregation capacity. Post-translationally, co-chaperones such as Hsp40 stimulate the ATPase activity of Hsp70 and modulate substrate targeting. The M-domain of Hsp104 controls its remodeling activity in an Hsp70/Hsp40-dependent manner, providing a built-in regulatory switch. Additionally, the ubiquitin-proteasome system and autophagy pathways can influence disaggregation by removing extracted proteins, creating a feedback loop that adjusts aggregate load. Small heat shock proteins also regulate disaggregation by controlling aggregate size and accessibility.
ATP-dependent protein disaggregase activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| HSPA1A | Neurodegeneration, cancer | Knockout and overexpression cell lines |
| HSPH1 | Protein misfolding disorders | Knock-in of disease-associated variants |
| HSPB1 | Charcot-Marie-Tooth disease, neurodegeneration | Point mutation knock-in models |
| CLPG | Bacterial stress survival and virulence | Bacterial knockout and complementation |
| VCP | IBMPFD, ALS | Knock-in of patient mutations |
Neurodegenerative diseases
Protein aggregation is a hallmark of neurodegenerative disorders such as Alzheimer's, Parkinson's and amyotrophic lateral sclerosis. Impaired ATP-dependent disaggregase activity can lead to the accumulation of toxic aggregates, and enhancing disaggregation is considered a therapeutic strategy. Small heat shock proteins, which cooperate with disaggregases, are also implicated in these diseases.
Cancer
Cancer cells often rely on robust proteostasis networks to survive proteotoxic stress. Disaggregase activity can contribute to resistance to chemotherapy and to the clearance of misfolded oncoproteins. Targeting disaggregation pathways is being explored as an anti-cancer approach.
Nuclear inclusion diseases
Chaperone-mediated protein disaggregation triggers proteolytic clearance of intra-nuclear protein inclusions, linking disaggregation to diseases characterized by nuclear aggregates. Defects in this pathway can lead to the persistence of toxic inclusions.
From ATP-dependent protein disaggregase activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of disaggregase cause aggregate accumulation? | CRISPR knockout of HSP104 or CLPG |
| How do disease mutations affect disaggregation? | Point mutation knock-in of HSPB1 or VCP |
| Can a tagged disaggregase track aggregate clearance? | Tagged knock-in of HSPA1A or HSPH1 |
| Does overexpression rescue aggregation? | Overexpression of HSPA1A, HSPH1 or DNAJB1 |
| What is the role of sHsps in disaggregation? | Knockout and overexpression of HSPB1 |
| How does disaggregation couple to degradation? | Knockout of VCP or UBB |
How to Study the ATP-dependent protein disaggregase activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Cell-free disaggregation assay | Reactivation of aggregated substrate | Mechanistic studies of Hsp110/Hsp70/Hsp40 |
| Cryo-EM | Structure of disaggregase-substrate complexes | Aggregate binding and threading |
| Fluorescence microscopy | Aggregate clearance in cells | Knockout/overexpression studies |
| Co-immunoprecipitation | Protein-protein interactions | Chaperone network mapping |
| ATPase assay | ATP hydrolysis rate | Regulation by co-chaperones |
| Proteomics | Global changes in aggregation | Stress response and disease models |
| CRISPR screening | Genes required for disaggregation | Functional genomics |
| Reporter assays | Transcriptional heat shock response | HSF1 regulation |
Biochemical disaggregation assays
Cell-free systems using purified Hsp110, Hsp70 and Hsp40 can reconstitute ATP-dependent disaggregation and measure reactivation of model substrates. These assays are used to dissect the synergy between chaperones and the requirement for ATP hydrolysis.
Structural biology
Cryo-EM and X-ray crystallography have revealed how AAA+ disaggregases such as ClpG bind aggregates and thread polypeptides. Structural studies of Hsp104 have elucidated the role of the M-domain in regulating remodeling activity.
Cell-based aggregate clearance assays
Fluorescently tagged aggregation-prone proteins can be expressed in cells to monitor aggregate formation and clearance in real time. Knockout or overexpression of disaggregase components reveals their contribution to aggregate removal.
Proteomics and interactomics
Mass spectrometry-based proteomics can identify proteins that co-aggregate and are disaggregated upon chaperone activity. Interactomics of Hsp70 with co-chaperones and substrates provides a network view of disaggregation.
How CRISPR Can Be Used to Study GO:0140545 ATP-dependent protein disaggregase activity
Knockout
CRISPR knockout of disaggregase genes such as HSP104 in yeast or CLPG in bacteria allows researchers to test whether loss of activity causes aggregate accumulation and stress sensitivity. In human cells, knockout of HSPA1A or HSPH1 can reveal their contribution to aggregate clearance.
Point Mutation
Point mutation knock-in can model disease-associated variants in genes like HSPB1 or VCP, enabling studies of how specific mutations affect disaggregation and disease phenotypes. This approach is valuable for dissecting structure-function relationships.
Knock-in
Tagged knock-in of disaggregase genes (e.g., GFP-HSPA1A) allows real-time tracking of protein localization and dynamics during aggregate clearance. Knock-in of reporter constructs can also monitor heat shock response activation.
Overexpression
Overexpression of Hsp110, Hsp70 or Hsp40 can enhance disaggregation capacity and rescue aggregation phenotypes in cellular models. This is useful for testing therapeutic potential of disaggregase augmentation.
How EDITGENE Supports ATP-dependent protein disaggregase activity Research
Researchers studying ATP-dependent protein disaggregase activity-related genes often need to determine whether a candidate gene is causally involved in aggregate clearance, stress survival or disease. EDITGENE provides CRISPR-based cell models and screening services to accelerate this discovery.
Contact EDITGENE today to design your custom CRISPR model for ATP-dependent protein disaggregase activity research.
Frequently Asked Questions About ATP-dependent protein disaggregase activity
What is ATP-dependent protein disaggregase activity?
It is a molecular function (GO:0140545) defined as an ATP-dependent chaperone activity that solubilizes ordered protein aggregates.
What genes are involved in ATP-dependent protein disaggregase activity?
Key genes include HSP104 in yeast, CLPG in bacteria, and HSPA1A, HSPH1 and DNAJB1 in humans.
How does ATP-dependent disaggregation work?
AAA+ disaggregases use ATP hydrolysis to thread polypeptides through a central pore, extracting them from aggregates.
What is the role of Hsp104 in disaggregation?
Hsp104 is a yeast AAA+ disaggregase whose M-domain controls remodeling activity in an Hsp70/Hsp40-dependent manner.
How do small heat shock proteins help disaggregation?
sHsps organize aggregates into accessible conformations that disaggregases can process.
Is ATP-dependent disaggregation linked to disease?
Yes, impaired disaggregation is associated with neurodegenerative diseases and cancer.
What methods are used to study disaggregase activity?
Cell-free assays, cryo-EM, fluorescence microscopy and proteomics are commonly used.
Can CRISPR be used to study disaggregase genes?
Yes, knockout, point mutation and knock-in models can reveal gene function in aggregate clearance.
What is the difference between Hsp104 and metazoan disaggregases?
Metazoa lack Hsp104 but use a synergistic Hsp110/Hsp70/Hsp40 system.
How is disaggregation coupled to protein degradation?
Disaggregation can trigger proteolytic clearance of extracted proteins via the ubiquitin-proteasome system.
Conclusion
ATP-dependent protein disaggregase activity (GO:0140545) is a vital molecular function that enables cells to reverse protein aggregation and maintain proteostasis. Its mechanisms, from AAA+ threading to Hsp110/Hsp70/Hsp40 synergy, are conserved across kingdoms and are linked to major human diseases. Continued research using CRISPR models and biochemical assays will further illuminate how disaggregation can be harnessed therapeutically.
References
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- 2. Mogk A et al.. 2017. Role of sHsps in organizing cytosolic protein aggregation and disaggregation.. Cell Stress Chaperones 22(4):493-502 PMID: 28120291
- 3. Katikaridis P et al.. 2023. Structural basis of aggregate binding by the AAA+ disaggregase ClpG.. J Biol Chem 299(11):105336 PMID: 37827289
- 4. Mogk A et al.. 2019. Cellular Functions and Mechanisms of Action of Small Heat Shock Proteins.. Annu Rev Microbiol 73:89-110 PMID: 31091419
- 5. Karunanayake C et al.. 2021. Cytosolic protein quality control machinery: Interactions of Hsp70 with a network of co-chaperones and substrates.. Exp Biol Med (Maywood) 246(12):1419-1434 PMID: 33730888
- 6. Shorter J. 2011. The mammalian disaggregase machinery: Hsp110 synergizes with Hsp70 and Hsp40 to catalyze protein disaggregation and reactivation in a cell-free system.. PLoS One 6(10):e26319 PMID: 22022600
- 7. Barends TR et al.. 2010. Disaggregases in 4 dimensions.. Curr Opin Struct Biol 20(1):46-53 PMID: 20083401
- 8. den Brave F et al.. 2020. Chaperone-Mediated Protein Disaggregation Triggers Proteolytic Clearance of Intra-nuclear Protein Inclusions.. Cell Rep 31(9):107680 PMID: 32492414
