GO:0061084 negative regulation of protein refolding: Mechanism, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0061084 (negative regulation of protein refolding) describes any process that decreases the rate, frequency, or extent of protein refolding, the chaperone-assisted restoration of biological activity to unfolded or misfolded proteins.
• Negative regulation can occur through direct inhibition of chaperone activity, sequestration of folding intermediates, or degradation of refolding-competent substrates.
• Key proteins involved include molecular chaperones such as Hsp70, Hsp40, Hsp90, and their co-chaperones, as well as proteases and aggregation-prone proteins.
• Dysregulation of protein refolding underlies conformational diseases including cancer, neurodegeneration, and metabolic disorders.
• Experimental approaches to study this process include refolding assays, proteomics, RNA-seq, and CRISPR-based gene editing.
• CRISPR knockout, point mutation, knock-in, and overexpression models enable precise interrogation of genes that negatively regulate protein refolding.
Description
Protein refolding is a fundamental cellular process that restores the biological activity of unfolded or misfolded proteins, typically with the assistance of molecular chaperones. The Gene Ontology term GO:0061084, negative regulation of protein refolding, encompasses any process that decreases the rate, frequency, or extent of this refolding activity. This regulation is critical for maintaining proteostasis and preventing the accumulation of toxic protein aggregates. Understanding negative regulation of protein refolding is essential because its dysregulation is implicated in a wide range of human diseases, from cancer to neurodegenerative disorders. Moreover, pathogens often exploit host refolding machinery, and viruses such as West Nile virus can be negatively regulated by chaperones like Hsp70. Thus, dissecting the molecular players and mechanisms of this GO term provides insights into both basic cell biology and therapeutic opportunities.
negative regulation of protein refolding At A Glance
| GO ID | GO:0061084 |
|---|---|
| GO term | negative regulation of protein refolding |
| Ontology | biological_process |
| Synonym | none |
| Major function | Decreases the rate, frequency, or extent of chaperone-assisted protein refolding |
| Definition source | QuickGO |
| Related process | Protein refolding (GO:0042026) |
| Regulation type | Negative regulation |
| Cellular context | Cytoplasm, endoplasmic reticulum, mitochondria |
What Is GO:0061084?
GO:0061084 is defined as any process that decreases the rate, frequency, or extent of protein refolding. Protein refolding itself is the process carried out by a cell that restores the biological activity of an unfolded or misfolded protein, using helper proteins such as chaperones. Therefore, negative regulation of protein refolding includes mechanisms that inhibit, slow down, or prevent the chaperone-mediated restoration of a protein's native structure and function.
Why Is negative regulation of protein refolding Important in Cell Biology?
Negative regulation of protein refolding is important because it serves as a quality control mechanism that prevents the accumulation of improperly folded proteins, which can be toxic to cells. By attenuating refolding, cells can direct misfolded proteins toward degradation pathways, thereby maintaining proteostasis. However, when this regulation is impaired, misfolded proteins may aggregate, leading to diseases such as Alzheimer's, Parkinson's, and certain cancers. Additionally, pathogens can hijack or be inhibited by components of the refolding machinery, as seen with West Nile virus capsid protein and Hsp70. Therefore, understanding this process is crucial for developing therapeutic strategies that target protein misfolding diseases.
• Maintains proteostasis by preventing toxic protein aggregation.
• Plays a role in cancer by influencing the folding and function of oncoproteins and tumor suppressors such as p53.
• Implicated in neurodegenerative disorders characterized by protein misfolding.
• Modulates viral replication through interactions with host chaperones.
• Affects cellular stress responses, including the heat shock response.
• Influences plant stress tolerance and transcriptomic regulation under heat stress.
• Provides targets for pharmacological intervention using chemical chaperones.
• Can be studied using recombinant protein refolding assays.
• Relevant to biotechnological production of recombinant proteins.
• Connected to oxidative stress and epigenetic regulation via G-quadruplexes.
What Happens During negative regulation of protein refolding?
Inhibition of Chaperone Activity
In simple terms: Chaperones help proteins fold correctly, but sometimes other molecules block them, slowing down refolding.
Negative regulation of protein refolding can occur through direct inhibition of chaperone function. For example, Hsp70 functions as a negative regulator of West Nile virus capsid protein by directly interacting with it, preventing proper folding and promoting its degradation. Similarly, small molecule regulators of the heat shock response can modulate chaperone activity, thereby affecting refolding rates.
Sequestration of Folding Intermediates
In simple terms: Misfolded proteins can be trapped by other proteins, preventing them from being refolded.
Certain proteins can bind to folding intermediates and sequester them, reducing the availability of substrates for refolding. This mechanism is observed in conformational disorders where mutant proteins form stable complexes with chaperones, leading to their functional inactivation. For instance, in p53 mutants, pharmacological reactivation strategies aim to overcome sequestration and restore folding.
Degradation of Refolding-Competent Substrates
In simple terms: Instead of being refolded, some proteins are targeted for destruction, which reduces refolding.
Negative regulation can also be achieved by promoting the degradation of proteins that would otherwise be refolded. This is often mediated by the ubiquitin-proteasome system, which recognizes misfolded proteins and directs them for proteasomal degradation, thereby decreasing the pool of refoldable substrates.
Regulation by Oxidative Stress and G-quadruplexes
In simple terms: Oxidative stress can change how genes are expressed, affecting the production of proteins involved in refolding.
Oxidative stress-mediated epigenetic regulation by G-quadruplexes can influence the expression of genes encoding chaperones and other refolding-related proteins, thereby indirectly modulating refolding capacity. This highlights a layer of regulation where cellular redox status impacts protein refolding through transcriptional and epigenetic mechanisms.
Key Genes Involved in GO:0061084 negative regulation of protein refolding
The following genes and proteins are key players in the negative regulation of protein refolding, based on published literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| HSPA1A (Hsp70) | Molecular chaperone; can negatively regulate viral capsid protein folding | Target for viral inhibition and cancer therapy |
| HSPA8 (Hsc70) | Constitutively expressed chaperone involved in protein folding and degradation | Model for chaperone-mediated refolding studies |
| DNAJB1 (Hsp40) | Co-chaperone that stimulates Hsp70 ATPase activity | Modulates Hsp70 substrate specificity |
| HSP90AA1 (Hsp90) | Chaperone for client proteins, including oncogenic kinases | Cancer drug target; regulates refolding of signaling proteins |
| STIP1 (Hop) | Co-chaperone that links Hsp70 and Hsp90 | Facilitates maturation of client proteins |
| BAG3 | Co-chaperone involved in autophagy and protein quality control | Implicated in cardiomyopathy and cancer |
| TP53 (p53) | Tumor suppressor; mutant p53 can be refolded by chaperones | Target for pharmacological reactivation in cancer |
| RIP2 (RIPK2) | Kinase with CARD domain; refolding studied in vitro | Model for recombinant protein refolding |
| MCA5 (metacaspase 5) | Trypanosoma cruzi metacaspase; refolding characterized | Parasite-specific refolding studies |
| HSF1 | Master transcription factor of heat shock response | Regulates chaperone expression |
| HSPB1 (Hsp27) | Small heat shock protein; holds misfolded proteins for refolding | Cytoprotective role in stress |
| CRYAB (alphaB-crystallin) | Small heat shock protein; prevents aggregation | Associated with cataract and myopathies |
| VCP (p97) | AAA+ ATPase involved in protein degradation and refolding | Mutations cause IBMPFD and ALS |
| UBB | Ubiquitin; tags proteins for degradation | Regulates proteostasis |
| SQSTM1 (p62) | Autophagy receptor; clears aggregates | Linked to neurodegeneration |
| NEFM | Neurofilament; aggregation-prone protein | Model for neurodegeneration |
| SOD1 | Superoxide dismutase; misfolding linked to ALS | Target for ALS research |
How Is negative regulation of protein refolding Regulated?
The negative regulation of protein refolding is itself regulated at multiple levels. The heat shock response, controlled by transcription factor HSF1, induces chaperone expression to enhance refolding capacity, but under certain conditions, chaperones like Hsp70 can act as negative regulators of specific substrates. Additionally, oxidative stress can modulate the expression of refolding-related genes through G-quadruplex-mediated epigenetic mechanisms. Small molecule regulators of the heat shock response can either enhance or inhibit chaperone activity, thereby affecting refolding rates. Furthermore, the ubiquitin-proteasome system and autophagy pathways compete with refolding by directing misfolded proteins to degradation, thus negatively regulating refolding.
negative regulation of protein refolding and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| TP53 | Cancer; mutant p53 misfolding | Knock-in of mutant p53 in cancer cell lines |
| SOD1 | ALS; protein aggregation | Overexpression of mutant SOD1 in neuronal cells |
| HSPA1A | Viral infection; West Nile virus | Knockout of Hsp70 in infected cells |
| CFTR | Cystic fibrosis; misfolding | Knock-in of F508del CFTR in airway epithelial cells |
| SNCA | Parkinson's disease; alpha-synuclein aggregation | Overexpression of A53T alpha-synuclein in neurons |
Cancer
In cancer, negative regulation of protein refolding can influence tumor progression by affecting the stability of oncoproteins and tumor suppressors. For example, mutant p53 often misfolds and is inactivated; pharmacological reactivation strategies aim to restore its folding and function, highlighting the importance of refolding regulation in precision oncology. Chaperones such as Hsp90 are overexpressed in many cancers and support the folding of oncogenic kinases, making them attractive drug targets.
Neurodegenerative Disorders
Neurodegenerative diseases like Alzheimer's and Parkinson's are characterized by the accumulation of misfolded protein aggregates. Negative regulation of refolding may exacerbate these conditions by preventing the clearance or refolding of toxic proteins. For instance, in amyotrophic lateral sclerosis (ALS), mutations in SOD1 lead to misfolding and aggregation, and chaperone-mediated refolding is impaired.
Viral Infections
Viruses often exploit host chaperones for their own protein folding. However, host factors can negatively regulate viral protein refolding, as seen with Hsp70 inhibiting West Nile virus capsid protein folding and promoting its degradation. This interplay suggests that modulating refolding regulation could be an antiviral strategy.
Metabolic and Conformational Disorders
Conformational disorders such as alpha-1 antitrypsin deficiency and cystic fibrosis involve misfolded proteins that are retained in the endoplasmic reticulum. Chemical chaperones can rescue folding defects, underscoring the therapeutic potential of targeting refolding regulation.
From negative regulation of protein refolding-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does gene X negatively regulate refolding of protein Y? | CRISPR knockout of gene X followed by refolding assay |
| How does a point mutation in a chaperone affect refolding? | CRISPR point mutation knock-in of the chaperone gene |
| What is the effect of overexpressing a negative regulator? | CRISPR overexpression (e.g., CRISPRa) of the gene |
| Where does the negative regulator localize? | Knock-in of a fluorescent tag (e.g., GFP) at the endogenous locus |
| What are the downstream targets of the regulator? | CRISPR knockout combined with proteomics or RNA-seq |
| Can a drug modulate the negative regulation? | CRISPR knockout of the target and treatment with small molecules |
How to Study the negative regulation of protein refolding Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Refolding assay | Recovery of protein activity or structure | Testing chaperone function and inhibitors |
| Co-immunoprecipitation | Protein-protein interactions | Identifying negative regulators of refolding |
| RNA-seq | Transcriptional changes | Profiling heat shock response genes |
| Proteomics | Protein abundance and modifications | Global analysis of proteostasis |
| CRISPR screen | Gene function on a genome-wide scale | Discovering new regulators of refolding |
| Fluorescence microscopy | Localization and aggregation of proteins | Visualizing misfolding in cells |
| Circular dichroism | Protein secondary structure | Monitoring refolding in vitro |
Refolding Assays
In vitro refolding assays using recombinant proteins, such as the CARD domain of RIP2 kinase or metacaspase 5, allow direct measurement of refolding kinetics and the impact of negative regulators. These assays typically involve denaturing the protein and then monitoring the recovery of activity or structure in the presence or absence of chaperones.
Proteomics and Interactomics
Mass spectrometry-based proteomics can identify proteins that interact with refolding intermediates and chaperones, revealing negative regulators. For example, immunoprecipitation of Hsp70 followed by mass spectrometry identified West Nile virus capsid protein as an interactor.
Transcriptomics and RNA-seq
RNA sequencing can uncover changes in gene expression associated with negative regulation of refolding, such as the heat stress response in Nothofagus pumilio. This approach helps identify pathways and regulators that modulate refolding capacity.
CRISPR Screening
Genome-wide CRISPR knockout or activation screens can systematically identify genes that negatively regulate protein refolding. For instance, a screen could use a reporter of protein misfolding and select for cells with altered refolding efficiency.
How CRISPR Can Be Used to Study GO:0061084 negative regulation of protein refolding
Knockout
CRISPR knockout of candidate genes, such as HSPA1A or TP53, enables researchers to determine whether the gene is required for negative regulation of protein refolding. For example, knocking out Hsp70 could increase refolding of a viral capsid protein, confirming its negative regulatory role.
Point Mutation
Introducing precise point mutations in genes encoding chaperones or substrates can reveal residues critical for negative regulation. For instance, mutating the ATPase domain of Hsp70 would test its requirement for inhibiting refolding.
Knock-in
Knock-in of tags (e.g., GFP, HA) at endogenous loci allows visualization and purification of proteins involved in refolding regulation. This can be used to track the localization of chaperones during stress.
Overexpression
CRISPR activation (CRISPRa) or cDNA overexpression can elevate levels of a suspected negative regulator, testing whether increased abundance reduces refolding. For example, overexpressing Hsp70 might enhance negative regulation of West Nile virus capsid protein.
How EDITGENE Supports negative regulation of protein refolding Research
Researchers studying negative regulation of protein refolding-related genes often need to determine whether a candidate gene is causally involved in modulating refolding efficiency, and whether its manipulation can alter disease-relevant phenotypes. EDITGENE provides a comprehensive suite of CRISPR-based services to address these questions with precision and scale.
Contact EDITGENE today to design your custom CRISPR model for negative regulation of protein refolding research.
Frequently Asked Questions About negative regulation of protein refolding
What is GO:0061084?
GO:0061084 is the Gene Ontology term for negative regulation of protein refolding, defined as any process that decreases the rate, frequency, or extent of protein refolding, the chaperone-assisted restoration of a protein's biological activity.
What genes are involved in negative regulation of protein refolding?
Key genes include HSPA1A (Hsp70), HSP90AA1, DNAJB1, TP53, and SOD1, among others, as reported in studies on chaperone function and protein misfolding.
How does negative regulation of protein refolding relate to cancer?
In cancer, negative regulation of refolding can affect the stability of oncoproteins and tumor suppressors; for example, mutant p53 misfolding and reactivation strategies highlight its importance.
What diseases are associated with defective protein refolding regulation?
Diseases include neurodegenerative disorders (Alzheimer's, Parkinson's, ALS), cancer, cystic fibrosis, and alpha-1 antitrypsin deficiency.
What methods are used to study negative regulation of protein refolding?
Methods include in vitro refolding assays, proteomics, RNA-seq, and CRISPR screens.
Can CRISPR be used to study negative regulation of protein refolding?
Yes, CRISPR knockout, point mutation, knock-in, and overexpression models allow precise manipulation of genes involved in this process.
What is the role of Hsp70 in protein refolding?
Hsp70 is a molecular chaperone that can both promote and negatively regulate refolding; it inhibits West Nile virus capsid protein folding through direct interaction.
How does oxidative stress affect protein refolding?
Oxidative stress can modulate gene expression via G-quadruplexes, influencing chaperone levels and thus refolding capacity.
What are chemical chaperones and how do they relate to this term?
Chemical chaperones are small molecules that can rescue folding defects; they modulate refolding and are studied in conformational disorders.
Why is negative regulation of protein refolding important for biotechnology?
It affects the yield of recombinant proteins; understanding refolding regulation can improve production of active proteins.
Conclusion
GO:0061084, negative regulation of protein refolding, is a critical biological process that ensures proteostasis by attenuating the chaperone-mediated refolding of unfolded or misfolded proteins. Its dysregulation is linked to cancer, neurodegeneration, and infectious diseases, making it a rich area for therapeutic intervention. Leveraging CRISPR-based models and advanced omics technologies, researchers can dissect the molecular players and mechanisms, paving the way for novel treatments.
References
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- 3. De Lima JY et al.. 2022. Refolding of metacaspase 5 from Trypanosoma cruzi, structural characterization and the influence of c-terminal in protein recombinant production.. Protein Expr Purif 191:106007 PMID: 34728367
- 4. Leandro P et al.. 2008. Protein misfolding in conformational disorders: rescue of folding defects and chemical chaperoning.. Mini Rev Med Chem 8(9):901-11 PMID: 18691147
- 5. Oh WK et al.. 2006. Hsp70 functions as a negative regulator of West Nile virus capsid protein through direct interaction.. Biochem Biophys Res Commun 347(4):994-1000 PMID: 16854374
- 6. Tuval A et al.. 2024. Pharmacological reactivation of p53 in the era of precision anticancer medicine.. Nat Rev Clin Oncol 21(2):106-120 PMID: 38102383
- 7. Kurop MK et al.. 2021. The heat shock response and small molecule regulators.. Eur J Med Chem 226:113846 PMID: 34563965
- 8. Estravis-Barcala M et al.. 2021. Deciphering the transcriptomic regulation of heat stress responses in Nothofagus pumilio.. PLoS One 16(3):e0246615 PMID: 33784314
