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Journal of Molecular Biology Mar 2019The various chaperone activities of heat shock proteins contribute to ensuring cellular proteostasis. Here, we demonstrate the non-canonical unfoldase activity as an...
The various chaperone activities of heat shock proteins contribute to ensuring cellular proteostasis. Here, we demonstrate the non-canonical unfoldase activity as an inherent functionality of the prokaryotic molecular chaperone, Hsp33. Hsp33 was originally identified as a holding chaperone that is post-translationally activated by oxidation. However, in this study, we verified that the holding-inactive reduced form of Hsp33 (Hsp33) strongly bound to the translational elongation factor, EF-Tu. This interaction was critically mediated by the redox-switch domain of Hsp33 and the guanine nucleotide-binding domain of EF-Tu. The bound Hsp33, without undergoing any conformational change, catalyzed the EF-Tu aggregation by evoking the aberrant folding of EF-Tu to expose hydrophobic surfaces. Consequently, the oligomers/aggregates of EF-Tu, but not its functional monomeric form, were highly susceptible to proteolytic degradation by Lon protease. These findings present a unique example of an ATP-independent molecular chaperone with distinctive dual functions-as an unfoldase/aggregase and as a holding chaperone-depending on the redox status. It is also suggested that the unusual unfoldase/aggregase activity of Hsp33 can contribute to cellular proteostasis by dysregulating EF-Tu under heat-stressed conditions.
Topics: Binding Sites; Escherichia coli; Escherichia coli Proteins; Heat-Shock Proteins; Molecular Chaperones; Oxidation-Reduction; Peptide Elongation Factor Tu; Protein Conformation; Protein Folding; Protein Interaction Domains and Motifs; Protein Processing, Post-Translational; Proteolysis
PubMed: 30822413
DOI: 10.1016/j.jmb.2019.02.022 -
The Journal of Biological Chemistry Jan 2015The aggregation of polyglutamine (polyQ)-containing proteins is at the origin of nine neurodegenerative diseases. Molecular chaperones prevent the aggregation of...
The aggregation of polyglutamine (polyQ)-containing proteins is at the origin of nine neurodegenerative diseases. Molecular chaperones prevent the aggregation of polyQ-containing proteins. The exact mechanism by which they interact with polyQ-containing, aggregation-prone proteins and interfere with their assembly is unknown. Here we dissect the mechanism of interaction between a huntingtin exon 1 fragment of increasing polyQ lengths (HttEx1Qn), the aggregation of which is tightly associated with Huntington's disease, and molecular chaperone Hsc70. We show that Hsc70, together with its Hsp40 co-chaperones, inhibits HttEx1Qn aggregation and modifies the structural, seeding, and infectious properties of the resulting fibrils in a polyQ-independent manner. We demonstrate that Hsc70 binds the 17-residue-long N-terminal flank of HttEx1Qn, and we map Hsc70-HttEx1Qn surface interfaces at the residue level. Finally, we show that this interaction competes with homotypic interactions between the N termini of different HttEx1Qn molecules that trigger the aggregation process. Our results lay the foundations of future therapeutic strategies targeting huntingtin aggregation in Huntington disease.
Topics: Exons; HSC70 Heat-Shock Proteins; Humans; Huntingtin Protein; Mass Spectrometry; Molecular Chaperones; Nerve Tissue Proteins; Peptides; Protein Binding
PubMed: 25505179
DOI: 10.1074/jbc.M114.603332 -
Proceedings of the Japan Academy.... 2014Chaperone therapy is a newly developed molecular therapeutic approach to protein misfolding diseases. Among them we found unstable mutant enzyme proteins in a few... (Review)
Review
Chaperone therapy is a newly developed molecular therapeutic approach to protein misfolding diseases. Among them we found unstable mutant enzyme proteins in a few lysosomal diseases, resulting in rapid intracellular degradation and loss of function. Active-site binding low molecular competitive inhibitors (chemical chaperones) paradoxically stabilized and enhanced the enzyme activity in somatic cells by correction of the misfolding of enzyme protein. They reached the brain through the blood-brain barrier after oral administration, and corrected pathophysiology of the disease. In addition to these inhibitory chaperones, non-competitive chaperones without inhibitory bioactivity are being developed. Furthermore molecular chaperone therapy utilizing the heat shock protein and other chaperone proteins induced by small molecules has been experimentally tried to handle abnormally accumulated proteins as a new approach particularly to neurodegenerative diseases. These three types of chaperones are promising candidates for various types of diseases, genetic or non-genetic, and neurological or non-neurological, in addition to lysosomal diseases.
Topics: Age of Onset; Animals; Humans; Molecular Chaperones; Molecular Targeted Therapy; Mutation; Proteostasis Deficiencies
PubMed: 24814990
DOI: 10.2183/pjab.90.145 -
Trends in Biochemical Sciences Apr 1998Genetic and biochemical work has highlighted the biological importance of the GroEL/GroES (Hsp60/Hsp10; cpn60/cpn10) chaperone machine in protein folding. GroEL's... (Review)
Review
Genetic and biochemical work has highlighted the biological importance of the GroEL/GroES (Hsp60/Hsp10; cpn60/cpn10) chaperone machine in protein folding. GroEL's donut-shaped structure has attracted the attention of structural biologists because of its elegance as well as the secrets (substrates) it can hide. The recent determination of the GroES and GroEL/GroES structures provides a glimpse of their plasticity, revealing dramatic conformational changes that point to an elaborate mechanism, coupling ATP hydrolysis to substrate release by GroEL.
Topics: Bacteriophage T4; Escherichia coli; Models, Molecular; Molecular Chaperones; Protein Conformation; Protein Folding
PubMed: 9584617
DOI: 10.1016/s0968-0004(98)01193-1 -
The International Journal of... May 1998Calreticulin is an ancient and highly conserved protein. It is intensively studied and has been assigned multiple functions, the scope and variety of which are... (Review)
Review
Calreticulin is an ancient and highly conserved protein. It is intensively studied and has been assigned multiple functions, the scope and variety of which are exceptionally wide for a single protein. Subsequent to the description of its calcium binding properties, calreticulin has been characterized as a molecular chaperone, an extracellular lectin, an intracellular mediator of integrin function, an inhibitor of steroid hormone-regulated gene expression and a C1q-binding protein. That one protein can perform so many functions is at once intriguing and controversial and further investigation is clearly required in order to fully understand the functions of calreticulin and elucidate its roles in disease. Based on current knowledge, calreticulin is being examined as a possible target for therapeutic intervention in steroid hormone-dependent conditions, such as osteoporosis, as well as for the development of novel anti-thrombotic agents.
Topics: Animals; Calcium-Binding Proteins; Calreticulin; Disease; Humans; Molecular Chaperones; Protein Conformation; Ribonucleoproteins
PubMed: 9693955
DOI: 10.1016/s1357-2725(97)00153-2 -
Annual Review of Microbiology Oct 2021Heat shock protein 90 (Hsp90) is a molecular chaperone that folds and remodels proteins, thereby regulating the activity of numerous substrate proteins. Hsp90 is widely... (Review)
Review
Heat shock protein 90 (Hsp90) is a molecular chaperone that folds and remodels proteins, thereby regulating the activity of numerous substrate proteins. Hsp90 is widely conserved across species and is essential in all eukaryotes and in some bacteria under stress conditions. To facilitate protein remodeling, bacterial Hsp90 collaborates with the Hsp70 molecular chaperone and its cochaperones. In contrast, the mechanism of protein remodeling performed by eukaryotic Hsp90 is more complex, involving more than 20 Hsp90 cochaperones in addition to Hsp70 and its cochaperones. In this review, we focus on recent progress toward understanding the basic mechanisms of bacterial Hsp90-mediated protein remodeling and the collaboration between Hsp90 and Hsp70. We describe the universally conserved structure and conformational dynamics of these chaperones and their interactions with one another and with client proteins. The physiological roles of Hsp90 in and other bacteria are also discussed. We anticipate that the information gained from exploring the mechanism of the bacterial chaperone system will provide a framework for understanding the more complex eukaryotic Hsp90 system.
Topics: Bacterial Proteins; Escherichia coli; Escherichia coli Proteins; HSP70 Heat-Shock Proteins; HSP90 Heat-Shock Proteins; Molecular Chaperones; Protein Binding
PubMed: 34375543
DOI: 10.1146/annurev-micro-032421-035644 -
Journal of Medicinal Chemistry Dec 2022Tumor necrosis factor receptor-associated protein 1 (TRAP1) is a mitochondrial molecular chaperone modulating cellular metabolism and signaling pathways by altering the... (Review)
Review
Tumor necrosis factor receptor-associated protein 1 (TRAP1) is a mitochondrial molecular chaperone modulating cellular metabolism and signaling pathways by altering the conformation, activity, and stability of numerous substrate proteins called clients. It exerts its chaperone function as an adaptive response to counter cellular stresses instead of maintaining housekeeping protein homeostasis. However, the stress-adaptive machinery becomes dysregulated to support the progression and maintenance of human diseases, such as cancers; therefore, TRAP1 has been proposed as a promising target protein for anticancer drug development. In this review, by collating recent reports on high-resolution TRAP1 structures and structure-activity relationships of inhibitors, we aimed to provide better insights into the chaperoning mechanism of the emerging drug target and to suggest an efficient strategy for the development of potent TRAP1 inhibitors.
Topics: Humans; Molecular Chaperones; HSP90 Heat-Shock Proteins; Mitochondria; Neoplasms
PubMed: 36507721
DOI: 10.1021/acs.jmedchem.2c01633 -
Molecular BioSystems Apr 2010SecB is a molecular chaperone in Gram-negative bacteria dedicated to the post-translational translocation of proteins across the cytoplasmic membrane. The entire surface... (Review)
Review
SecB is a molecular chaperone in Gram-negative bacteria dedicated to the post-translational translocation of proteins across the cytoplasmic membrane. The entire surface of this chaperone is used for both of its native functions in protein targeting and unfolding. Single molecule studies revealed how SecB affects the folding pathway of proteins and how it prevents the tertiary structure formation and aggregation to support protein translocation.
Topics: Bacterial Proteins; Gram-Negative Bacteria; Models, Biological; Models, Molecular; Molecular Chaperones; Protein Folding; Protein Processing, Post-Translational; Protein Transport; Systems Biology
PubMed: 20237639
DOI: 10.1039/b915435c -
Genes Aug 2022The J-proteins, also called DNAJ-proteins or heat shock protein 40 (HSP40), are one of the famous molecular chaperones. J-proteins, HSP70s and other chaperones work... (Review)
Review
The J-proteins, also called DNAJ-proteins or heat shock protein 40 (HSP40), are one of the famous molecular chaperones. J-proteins, HSP70s and other chaperones work together as constitute ubiquitous types of molecular chaperone complex, which function in a wide variety of physiological processes. J-proteins are widely distributed in major cellular compartments. In the chloroplast of higher plants, around 18 J-proteins and multiple J-like proteins are present; however, the functions of most of them remain unclear. During the last few years, important progress has been made in the research on their roles in plants. There is increasing evidence that the chloroplast J-proteins play essential roles in chloroplast development, photosynthesis, seed germination and stress response. Here, we summarize recent research advances on the roles of J-proteins in the chloroplast, and discuss the open questions that remain in this field.
Topics: Chloroplast Proteins; Chloroplasts; HSP70 Heat-Shock Proteins; Molecular Chaperones; Plants
PubMed: 36011380
DOI: 10.3390/genes13081469 -
Journal of Biotechnology Jan 2020The soluble expression of recombinant proteins in Escherichia coli is vital for protein applications in biotechnology and pharmaceuticals. However, the use of E. coli...
The soluble expression of recombinant proteins in Escherichia coli is vital for protein applications in biotechnology and pharmaceuticals. However, the use of E. coli for efficient heterologous protein expression is hampered by several factors, such as poor expression and protein aggregation. Changing the culture or purification conditions may alleviate these issues, but methods based on gene fusion technology offer unique opportunities to improve the production and purification of soluble proteins. Here, we develop a novel fusion tag based on Spy, a newly identified molecular chaperone that functions in the periplasm of E. coli in an ATP-independent manner to prevent protein aggregation and assist in protein folding. We found that the tandem fusion of Spy stands among the well-described best fusion partners, such as MBP and SUMO, in increasing the soluble steady-state levels of six heterologous passenger proteins. Moreover, an easily aggregated passenger protein remained soluble after the removal of the Spy tag, implying that chaperone-dependent folding occurred when the passenger protein was fused to Spy. Our work expands the toolkit of fusion tags and allows them to aid in the production of unstable proteins with industrial or clinical values.
Topics: Biotechnology; Escherichia coli; Escherichia coli Proteins; Formate Dehydrogenases; Molecular Chaperones; Periplasm; Periplasmic Proteins; Protein Folding; Protein Processing, Post-Translational; Recombinant Fusion Proteins; Solubility
PubMed: 31705934
DOI: 10.1016/j.jbiotec.2019.11.006