GO:0006457 protein folding: Proteostasis Pathway, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0006457 (protein folding) is the biological process that assists single-chain polypeptides or multisubunit complexes to acquire their correct three-dimensional tertiary structure.
• Protein folding is driven by the amino-acid sequence but is often assisted by molecular chaperones and folding catalysts that prevent aggregation and ensure fidelity.
• Folding can occur co-translationally, and translation rate influences the efficiency and outcome of folding.
• Oxidative protein folding in the endoplasmic reticulum requires dedicated redox machinery to form native disulfide bonds and maintain redoxtasis.
• Defects in protein folding and chaperone function are linked to neurodegeneration, cancer, and other conformational diseases.
• CRISPR-based knockout, point-mutation, knock-in, and overexpression models enable causal testing of folding-related genes in disease and basic biology.
Description
Protein folding (GO:0006457) is the biological process of assisting in the covalent and noncovalent assembly of single-chain polypeptides or multisubunit complexes into the correct tertiary structure. It is a fundamental cellular activity that converts linear genetic information into functional three-dimensional proteins, and its failure can lead to loss-of-function, aggregation, or toxicity. Researchers study protein folding to understand how cells maintain proteostasis, how folding is coupled to translation, and how folding defects contribute to human disease. The process is not merely spontaneous; it is often guided by molecular chaperones and folding catalysts that consume energy and create a protected environment for folding intermediates. Because folding is central to nearly every cellular pathway, GO:0006457 is a high-value term for functional genomics, drug discovery, and disease modeling.
protein folding At A Glance
| GO ID | GO:0006457 |
|---|---|
| GO term | protein folding |
| Ontology | biological_process |
| Synonym | chaperone activity; chaperonin ATPase activity; co-chaperone activity; protein complex assembly; multichaperone pathway |
| Major function | Assisting polypeptides and multisubunit complexes to reach their correct tertiary structure |
| Definition source | QuickGO definition: The process of assisting in the covalent and noncovalent assembly of single chain polypeptides or multisubunit complexes into the correct tertiary structure |
| Related processes | Co-translational folding, oxidative protein folding, chaperone-mediated folding, proteostasis |
| Key cellular locations | Cytosol, endoplasmic reticulum, mitochondria, nucleus |
| Disease relevance | Neurodegeneration, cancer, conformational diseases, ER stress disorders |
What Is GO:0006457?
According to the Gene Ontology, GO:0006457 (protein folding) is defined as the process of assisting in the covalent and noncovalent assembly of single chain polypeptides or multisubunit complexes into the correct tertiary structure. In other words, it encompasses all cellular activities that help a newly synthesized or stress-denatured polypeptide attain its biologically active conformation, including chaperone-assisted folding, disulfide bond formation, proline isomerization, and quality-control steps that monitor folding fidelity.
Why Is protein folding Important in Cell Biology?
Protein folding is essential because the biological function of most proteins depends on their correct three-dimensional structure, and misfolded proteins can be toxic or nonfunctional. Chaperones and folding catalysts are required for proteostasis, especially under stress conditions, and their dysfunction is implicated in a wide range of human diseases, including neurodegenerative disorders and cancer. Understanding GO:0006457 therefore provides mechanistic insight into how cells maintain protein quality control and how this process can be targeted therapeutically.
• Ensures that newly synthesized polypeptides attain functional conformations.
• Prevents aggregation of folding intermediates, which is toxic to cells.
• Enables co-translational folding and coupling of translation rate to folding efficiency.
• Supports oxidative protein folding and disulfide bond formation in the endoplasmic reticulum.
• Maintains proteostasis under stress and during aging.
• Is linked to neurodegeneration, cancer, and other conformational diseases.
• Provides targets for pharmacological chaperones and proteostasis regulators.
• Is a core process for functional genomics and CRISPR-based disease modeling.
What Happens During protein folding?
Synthesis and co-translational folding
In simple terms: Proteins begin to fold as they are being made by the ribosome.
Protein folding often begins co-translationally, meaning that the nascent polypeptide chain starts to acquire secondary and tertiary structure as it emerges from the ribosome. Translation rate can influence folding outcomes, and perturbations in elongation kinetics can lead to misfolding or aggregation. This coupling ensures that folding is coordinated with synthesis and that quality-control systems can act early.
Chaperone-assisted folding
In simple terms: Molecular chaperones help proteins fold correctly and prevent them from clumping together.
Molecular chaperones bind to exposed hydrophobic regions of folding intermediates and assist in achieving the native state, often in an ATP-dependent manner. Chaperone systems such as Hsp70, Hsp90, and chaperonins create isolated environments that favor productive folding and prevent aggregation. These chaperones are central to the definition of GO:0006457 because they assist in the covalent and noncovalent assembly of polypeptides into the correct tertiary structure.
Oxidative folding and disulfide bond formation
In simple terms: In the endoplasmic reticulum, special enzymes form the correct disulfide bonds that stabilize protein structure.
Oxidative protein folding in the endoplasmic reticulum involves the formation, reduction, and isomerization of disulfide bonds, which are essential for the stability and function of many secreted and membrane proteins. This process requires a redox-balanced environment and dedicated enzymes such as protein disulfide isomerases and Ero1. Fidelity of oxidative folding is critical for redoxtasis and for preventing ER stress.
Conformational quality control and degradation
In simple terms: Cells check whether proteins folded correctly and destroy those that did not.
Folding is coupled to quality-control pathways that recognize terminally misfolded proteins and target them for degradation, for example via the ubiquitin-proteasome system or ER-associated degradation. This ensures that only properly folded proteins reach their functional destinations and that misfolded species do not accumulate. Defects in quality control contribute to conformational diseases.
Multisubunit complex assembly
In simple terms: Many proteins must assemble with partner subunits to become functional machines.
GO:0006457 also covers the assembly of multisubunit complexes into the correct tertiary structure. Chaperones assist in the ordered assembly of subunits, preventing off-pathway interactions and ensuring stoichiometric balance. This is particularly important for large complexes such as ribosomes, proteasomes, and chaperonins themselves.
Key Genes Involved in GO:0006457 protein folding
The following genes and proteins are central to protein folding (GO:0006457) and are widely studied in mechanistic and disease research.
| Gene | Major Role | Research Relevance |
|---|---|---|
| HSPA1A | Hsp70 chaperone; ATP-dependent protein folding | Stress response, proteostasis, cancer |
| HSPA8 | Hsc70; constitutive chaperone for folding and trafficking | Co-translational folding, neurodegeneration |
| HSP90AA1 | Hsp90 chaperone; maturation of client proteins | Cancer, signal transduction |
| HSPD1 | Hsp60 chaperonin subunit; mitochondrial protein folding | Mitochondrial proteostasis, neurodegeneration |
| HSPE1 | Hsp10 co-chaperonin; assists Hsp60 | Mitochondrial folding, chaperonin mechanism |
| DNAJB1 | Hsp40 co-chaperone; stimulates Hsp70 ATPase | Protein quality control, cancer |
| DNAJC proteins | Co-chaperones that regulate Hsp70 function | Folding, ER stress, neurodegeneration |
| PDIA1 (P4HB) | Protein disulfide isomerase; oxidative folding | ER redox, secreted protein folding |
| ERO1A | ER oxidoreductin; disulfide bond formation | Oxidative folding, ER stress |
| CALR | Calreticulin; ER lectin chaperone | Glycoprotein folding, immunogenicity |
| CANX | Calnexin; ER membrane lectin chaperone | Glycoprotein folding, quality control |
| HSPB1 | Small heat shock protein; holds misfolded proteins | Aggregation prevention, neurodegeneration |
| BAG3 | Co-chaperone; chaperone-assisted selective autophagy | Proteostasis, cardiomyopathy |
| STIP1 | Co-chaperone linking Hsp70 and Hsp90 | Chaperone machinery, cancer |
| PPIH | Peptidyl-prolyl isomerase; proline isomerization | Folding catalysis, immune regulation |
| FKBP1A | FKBP prolyl isomerase; folding and signaling | Immunosuppression, folding |
| CCT subunits | Chaperonin containing TCP-1; cytoskeletal protein folding | Actin/tubulin folding, cell cycle |
How Is protein folding Regulated?
Protein folding (GO:0006457) is regulated at multiple levels, including transcription of chaperone genes, translation rate, and post-translational modification of folding machinery. The heat shock response and the unfolded protein response (UPR) are major stress-responsive pathways that upregulate chaperones and folding catalysts to restore proteostasis. Translation elongation rates can modulate co-translational folding, and changes in these rates can alter folding outcomes. Redox balance in the endoplasmic reticulum regulates oxidative folding and disulfide bond formation. Additionally, co-chaperones and nucleotide exchange factors dynamically regulate chaperone ATPase cycles.
protein folding and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| HSPA1A | Neurodegeneration, cancer | Knockout and overexpression in neuronal and cancer cell lines |
| HSP90AA1 | Cancer, signal transduction | Point mutation of ATP-binding domain; knock-in |
| PDIA1 (P4HB) | ER stress, metabolic disease | Knockout in hepatocytes; oxidative folding assays |
| CALR | Myeloproliferative neoplasms, ER folding | Knock-in of mutant CALR; glycoprotein folding |
| HSPD1 | Mitochondrial chaperonopathy, neurodegeneration | Knockout in iPSC-derived neurons; mitochondrial folding |
Protein folding in neurodegeneration
Misfolding and aggregation of proteins are hallmarks of many neurodegenerative diseases, and chaperone dysfunction exacerbates these pathologies. For example, impaired Hsp70/Hsp90 function can lead to accumulation of toxic protein species. Understanding GO:0006457 provides a framework for developing chaperone-based therapeutics.
Protein folding in cancer
Cancer cells often depend on chaperones and folding machinery to cope with high proteotoxic stress, making folding pathways attractive therapeutic targets. Hsp90 inhibitors and other proteostasis modulators are being explored in oncology. Folding-related genes can also influence drug resistance and metastasis.
Protein folding in ER stress and metabolic disease
Defects in oxidative protein folding in the endoplasmic reticulum cause ER stress and are linked to metabolic and inflammatory diseases. Mutations in ER folding enzymes can lead to protein misfolding disorders. Targeting ER redox pathways is a potential therapeutic strategy.
Protein folding in genetic disorders
Many inherited diseases are caused by mutations that impair protein folding, leading to loss of function or toxic gain of function. Chaperone therapy and pharmacological chaperones aim to correct folding defects. CRISPR models of these mutations enable mechanistic studies and drug testing.
From protein folding-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of a chaperone gene impair folding and cause aggregation? | CRISPR knockout cell line |
| Does a disease-associated point mutation alter chaperone function? | Point-mutation knock-in |
| Can a folding enzyme be tagged for live imaging? | Tagged knock-in (e.g., GFP) |
| Does overexpression of a chaperone rescue folding defects? | Overexpression cell model |
| Which genes regulate proteostasis under stress? | CRISPR library screening |
| What are the transcriptomic consequences of folding defects? | RNA-seq and Ribo-seq |
How to Study the protein folding Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Ribo-seq | Ribosome occupancy and translation rate | Co-translational folding studies |
| RNA-seq | Transcriptome changes | Stress response and chaperone induction |
| Proteomics | Protein abundance and interactions | Chaperone client identification |
| Single-molecule FRET | Folding dynamics and heterogeneity | Mechanistic folding studies |
| CRISPR screen | Gene essentiality for folding | Discovery of folding regulators |
| Live-cell imaging | Protein localization and aggregation | Proteostasis monitoring |
| Chemical crosslinking | Folding intermediates and complexes | Structural characterization |
Ribo-seq and translation profiling
Ribo-seq measures ribosome occupancy and translation rates, which are directly linked to co-translational folding. It can reveal how changes in elongation kinetics affect folding outcomes. Combining Ribo-seq with proteomics provides a systems view of folding.
Proteomics and interactomics
Mass spectrometry-based proteomics can identify chaperone clients, folding intermediates, and aggregation-prone proteins. Interactomics reveals dynamic chaperone-co-chaperone networks. These methods are essential for defining the molecular players in GO:0006457.
Imaging and conformational reporters
Fluorescence-based reporters and single-molecule imaging visualize protein folding and unfolding in real time. These techniques reveal heterogeneity in folding pathways and kinetics. They are powerful for studying folding in living cells.
CRISPR screens and functional genomics
Genome-wide CRISPR screens can identify genes required for folding and proteostasis under stress. Such screens link GO:0006457 to specific cellular vulnerabilities. Follow-up validation uses targeted knockouts and point mutations.
How CRISPR Can Be Used to Study GO:0006457 protein folding
Knockout
CRISPR knockout of folding-related genes (e.g., HSPA1A, HSP90AA1) enables loss-of-function studies to determine their role in proteostasis and disease. Knockout cell lines can be used to assess aggregation, stress sensitivity, and drug response.
Point Mutation
Point-mutation knock-in models replicate disease-associated missense mutations in chaperones or folding enzymes, allowing precise functional analysis. These models are valuable for testing pharmacological chaperones.
Knock-in
Tagged knock-in (e.g., GFP or HA) of folding genes enables live imaging and biochemical purification of chaperone complexes. Knock-in of reporter cassettes can monitor folding stress in real time.
Overexpression
Overexpression of chaperones or folding catalysts can rescue folding defects and test sufficiency in disease models. Overexpression models are also used to study chaperone overload and proteostasis.
How EDITGENE Supports protein folding Research
Researchers studying protein folding-related genes often need to determine whether a candidate gene is causally involved in folding, proteostasis, 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 protein folding research.
Frequently Asked Questions About protein folding
What is GO:0006457 protein folding?
GO:0006457 is the Gene Ontology term for the biological process of assisting in the covalent and noncovalent assembly of single chain polypeptides or multisubunit complexes into the correct tertiary structure.
What genes are involved in protein folding?
Key genes include HSPA1A, HSPA8, HSP90AA1, HSPD1, HSPE1, DNAJB1, PDIA1, ERO1A, CALR, CANX, and chaperonin subunits.
Why is protein folding important?
Correct folding is required for protein function, and misfolding causes aggregation and disease; chaperones maintain proteostasis.
How is protein folding regulated?
It is regulated by chaperone expression, translation rate, the unfolded protein response, and redox balance in the ER.
What diseases are linked to protein folding defects?
Neurodegeneration, cancer, ER stress disorders, and genetic conformational diseases.
What methods study protein folding?
Ribo-seq, proteomics, single-molecule FRET, imaging, and CRISPR screens.
Can CRISPR be used to study protein folding?
Yes, knockout, point-mutation, knock-in, and overexpression models enable causal studies of folding genes.
What is the role of chaperones in protein folding?
Chaperones bind folding intermediates and assist in achieving the native state, often using ATP.
What is oxidative protein folding?
It is the formation of disulfide bonds in the endoplasmic reticulum, essential for many secreted proteins.
How does translation rate affect folding?
Translation elongation rate influences co-translational folding and can determine folding outcomes.
Conclusion
Protein folding (GO:0006457) is a central biological process that ensures proteins attain their functional three-dimensional structure, with chaperones and folding catalysts playing essential roles. Its dysfunction is implicated in numerous diseases, making it a key area for mechanistic and therapeutic research. CRISPR-based models and functional genomics provide powerful tools to dissect folding pathways and identify new targets.
References
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- 2. Ferina J et al.. 2019. Visualizing Protein Folding and Unfolding.. J Mol Biol 431(8):1540-1564 PMID: 30840846
- 3. Fedorov AN. 2022. Biosynthetic Protein Folding and Molecular Chaperons.. Biochemistry (Mosc) 87(Suppl 1):S128-S19 PMID: 35501992
- 4. Sorokina I et al.. 2022. Is Protein Folding a Thermodynamically Unfavorable, Active, Energy-Dependent Process?. Int J Mol Sci 23(1) PMID: 35008947
- 5. Bhatia S et al.. 2022. Heterogeneity in Protein Folding and Unfolding Reactions.. Chem Rev 122(9):8911-8935 PMID: 35275612
- 6. Komar AA et al.. 2024. Translation Rates and Protein Folding.. J Mol Biol 436(14):168384 PMID: 38065274
- 7. Basharov MA. 2003. Protein folding.. J Cell Mol Med 7(3):223-37 PMID: 14594547
- 8. Wang L et al.. 2023. Oxidative protein folding fidelity and redoxtasis in the endoplasmic reticulum.. Trends Biochem Sci 48(1):40-52 PMID: 35871147
