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Kuzminov A. Bacterial nucleoid is a riddle wrapped in a mystery inside an enigma. J Bacteriol 2024; 206:e0021123. [PMID: 38358278 PMCID: PMC10994824 DOI: 10.1128/jb.00211-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2024] Open
Abstract
Bacterial chromosome, the nucleoid, is traditionally modeled as a rosette of DNA mega-loops, organized around proteinaceous central scaffold by nucleoid-associated proteins (NAPs), and mixed with the cytoplasm by transcription and translation. Electron microscopy of fixed cells confirms dispersal of the cloud-like nucleoid within the ribosome-filled cytoplasm. Here, I discuss evidence that the nucleoid in live cells forms DNA phase separate from riboprotein phase, the "riboid." I argue that the nucleoid-riboid interphase, where DNA interacts with NAPs, transcribing RNA polymerases, nascent transcripts, and ssRNA chaperones, forms the transcription zone. An active part of phase separation, transcription zone enforces segregation of the centrally positioned information phase (the nucleoid) from the surrounding action phase (the riboid), where translation happens, protein accumulates, and metabolism occurs. I speculate that HU NAP mostly tiles up the nucleoid periphery-facilitating DNA mobility but also supporting transcription in the interphase. Besides extruding plectonemically supercoiled DNA mega-loops, condensins could compact them into solenoids of uniform rings, while HU could support rigidity and rotation of these DNA rings. The two-phase cytoplasm arrangement allows the bacterial cell to organize the central dogma activities, where (from the cell center to its periphery) DNA replicates and segregates, DNA is transcribed, nascent mRNA is handed over to ribosomes, mRNA is translated into proteins, and finally, the used mRNA is recycled into nucleotides at the inner membrane. The resulting information-action conveyor, with one activity naturally leading to the next one, explains the efficiency of prokaryotic cell design-even though its main intracellular transportation mode is free diffusion.
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Affiliation(s)
- Andrei Kuzminov
- Department of Microbiology, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
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2
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Ferdosh S, Banerjee S, Singh J, Barat C. Amyloid protein-induced sequestration of the eukaryotic ribosome: effect of stoichiometry and polyphenolic inhibitors. FEBS Lett 2022; 596:1190-1202. [PMID: 35114013 DOI: 10.1002/1873-3468.14308] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 01/12/2022] [Accepted: 01/22/2022] [Indexed: 11/07/2022]
Abstract
Alzheimer's disease (AD) is characterized by the appearance of neurofibrillary tangles comprising of the Tau protein and aggregation of amyloid-β peptides (Aβ 1-40 and Aβ 1-42). A concomitant loss of the ribosomal population is also observed in AD-affected neurons. Our studies demonstrate that, similarly to Tau protein aggregation, in vitro aggregation of Aβ peptides in the vicinity of the yeast 80S ribosome can induce co-aggregation of ribosomal components. The RNA-stimulated aggregation of Aβ peptides and the Tau-K18 variant is dependent on the RNA:protein stoichiometric ratio. A similar effect of stoichiometry is also observed on the ribosome-protein co-aggregation process. Polyphenolic inhibitors of amyloid aggregation, such as rosmarinic acid and myricetin, inhibit RNA-stimulated Aβ and Tau-K18 aggregation and can mitigate the co-aggregation of ribosomal components.
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Affiliation(s)
- Sehnaz Ferdosh
- Department of Biotechnology, St. Xavier's College, Kolkata, India
| | - Senjuti Banerjee
- Department of Biotechnology, St. Xavier's College, Kolkata, India
| | - Jayshree Singh
- Department of Biotechnology, St. Xavier's College, Kolkata, India
| | - Chandana Barat
- Department of Biotechnology, St. Xavier's College, Kolkata, India
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3
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Pang Y, Kovachev P, Sanyal S. Ribosomal RNA Modulates Aggregation of the Podospora Prion Protein HET-s. Int J Mol Sci 2020; 21:ijms21176340. [PMID: 32882892 PMCID: PMC7504336 DOI: 10.3390/ijms21176340] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 08/28/2020] [Indexed: 01/19/2023] Open
Abstract
The role of the nucleic acids in prion aggregation/disaggregation is becoming more and more evident. Here, using HET-s prion from fungi Podospora anserina (P. anserina) as a model system, we studied the role of RNA, particularly of different domains of the ribosomal RNA (rRNA), in its aggregation process. Our results using Rayleigh light scattering, Thioflavin T (ThT) binding, transmission electron microscopy (TEM) and cross-seeding assay show that rRNA, in particular the domain V of the major rRNA from the large subunit of the ribosome, substantially prevents insoluble amyloid and amorphous aggregation of the HET-s prion in a concentration-dependent manner. Instead, it facilitates the formation of the soluble oligomeric “seeds”, which are capable of promoting de novo HET-s aggregation. The sites of interactions of the HET-s prion protein on domain V rRNA were identified by primer extension analysis followed by UV-crosslinking, which overlap with the sites previously identified for the protein-folding activity of the ribosome (PFAR). This study clarifies a missing link between the rRNA-based PFAR and the mode of propagation of the fungal prions.
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4
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Ferdosh S, Banerjee S, Pathak BK, Sengupta J, Barat C. Hibernating ribosomes exhibit chaperoning activity but can resist unfolded protein-mediated subunit dissociation. FEBS J 2020; 288:1305-1324. [PMID: 32649051 DOI: 10.1111/febs.15479] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 06/24/2020] [Accepted: 07/07/2020] [Indexed: 02/03/2023]
Abstract
Ribosome hibernation is a prominent cellular strategy to modulate protein synthesis during starvation and the stationary phase of bacterial cell growth. Translational suppression involves the formation of either factor-bound inactive 70S monomers or dimeric 100S hibernating ribosomal complexes, the biological significance of which is poorly understood. Here, we demonstrate that the Escherichia coli 70S ribosome associated with stationary phase factors hibernation promoting factor or protein Y or ribosome-associated inhibitor A and the 100S ribosome isolated from both Gram-negative and Gram-positive bacteria are resistant to unfolded protein-mediated subunit dissociation and subsequent degradation by cellular ribonucleases. Considering that the increase in cellular stress is accompanied by accumulation of unfolded proteins, such resistance of hibernating ribosomes towards dissociation might contribute to their maintenance during the stationary phase. Analysis of existing structures provided clues on the mechanism of inhibition of the unfolded protein-mediated disassembly in case of hibernating factor-bound ribosome. Further, the factor-bound 70S and 100S ribosomes can suppress protein aggregation and assist in protein folding. The chaperoning activity of these ribosomes is the first evidence of a potential biological activity of the hibernating ribosome that might be crucial for cell survival under stress conditions.
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Affiliation(s)
- Sehnaz Ferdosh
- Department of Biotechnology, St. Xavier's College, Kolkata, India
| | - Senjuti Banerjee
- Department of Biotechnology, St. Xavier's College, Kolkata, India
| | - Bani K Pathak
- Structural Biology and Bio-Informatics Division, Indian Institute of Chemical Biology (Council of Scientific and Industrial Research), Kolkata, India
| | - Jayati Sengupta
- Structural Biology and Bio-Informatics Division, Indian Institute of Chemical Biology (Council of Scientific and Industrial Research), Kolkata, India
| | - Chandana Barat
- Department of Biotechnology, St. Xavier's College, Kolkata, India
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5
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Zacco E, Graña-Montes R, Martin SR, de Groot NS, Alfano C, Tartaglia GG, Pastore A. RNA as a key factor in driving or preventing self-assembly of the TAR DNA-binding protein 43. J Mol Biol 2019; 431:1671-1688. [PMID: 30742796 PMCID: PMC6461199 DOI: 10.1016/j.jmb.2019.01.028] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 01/22/2019] [Accepted: 01/24/2019] [Indexed: 12/12/2022]
Abstract
Amyotrophic lateral sclerosis and frontotemporal lobar degeneration are incurable motor neuron diseases associated with muscle weakness, paralysis and respiratory failure. Accumulation of TAR DNA-binding protein 43 (TDP-43) as toxic cytoplasmic inclusions is one of the hallmarks of these pathologies. TDP-43 is an RNA-binding protein responsible for regulating RNA transcription, splicing, transport and translation. Aggregated TDP-43 does not retain its physiological function. Here, we exploit the ability of TDP-43 to bind specific RNA sequences to validate our hypothesis that the native partners of a protein can be used to interfere with its ability to self-assemble into aggregates. We propose that binding of TDP-43 to specific RNA can compete with protein aggregation. This study provides a solid proof of concept to the hypothesis that natural interactions can be exploited to increase protein solubility and could be adopted as a more general rational therapeutic strategy. We found that binding of the RRM domains of TDP-43 to specific RNA competes with protein aggregation. This study provides a solid proof of concept to the hypothesis that natural interactions can be exploited to increase protein solubility. The concept could be adopted as a more general rationale for protein-specific drug design.
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Affiliation(s)
- Elsa Zacco
- UK Dementia Research Institute at King's College London, London, SE5 9RT, United Kingdom; The Wohl Institute at King's College London, London, SE5 9RT, United Kingdom
| | - Ricardo Graña-Montes
- Centre for Genomic Regulation (CRG), The Barcelona Institute for Science and Technology, Dr. Aiguader 88, 08003 Barcelona, Spain
| | | | - Natalia Sanchez de Groot
- Centre for Genomic Regulation (CRG), The Barcelona Institute for Science and Technology, Dr. Aiguader 88, 08003 Barcelona, Spain
| | | | - Gian Gaetano Tartaglia
- Centre for Genomic Regulation (CRG), The Barcelona Institute for Science and Technology, Dr. Aiguader 88, 08003 Barcelona, Spain; Universitat Pompeu Fabra (UPF), Barcelona 08003, Spain; Institutio Catalan de Recerca I Estudis Avancats (ICREA), 23 Passeig Lluıs Companys, 08010 Barcelona, Spain; Department of Biology 'Charles Darwin', Sapienza University of Rome, P.le A. Moro 5, Rome 00185, Italy.
| | - Annalisa Pastore
- UK Dementia Research Institute at King's College London, London, SE5 9RT, United Kingdom; The Wohl Institute at King's College London, London, SE5 9RT, United Kingdom; Scuola Normale Superiore, Piazza dei Cavalieri, Pisa, 56126, Italy.
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6
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Houwman JA, Westphal AH, Visser AJWG, Borst JW, van Mierlo CPM. Concurrent presence of on- and off-pathway folding intermediates of apoflavodoxin at physiological ionic strength. Phys Chem Chem Phys 2018; 20:7059-7072. [PMID: 29473921 DOI: 10.1039/c7cp07922b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Flavodoxins have a protein topology that can be traced back to the universal ancestor of the three kingdoms of life. Proteins with this type of architecture tend to temporarily misfold during unassisted folding to their native state and form intermediates. Several of these intermediate species are molten globules (MGs), which are characterized by a substantial amount of secondary structure, yet without the tertiary side-chain packing of natively folded proteins. An off-pathway MG is formed at physiological ionic strength in the case of the F44Y variant of Azotobacter vinelandii apoflavodoxin (i.e., flavodoxin without flavin mononucleotide (FMN)). Here, we show that at this condition actually two folding species of this apoprotein co-exist at equilibrium. These species were detected by using a combination of FMN fluorescence quenching upon cofactor binding to the apoprotein and of polarized time-resolved tryptophan fluorescence spectroscopy. Besides the off-pathway MG, we observe the simultaneous presence of an on-pathway folding intermediate, which is native-like. Presence of concurrent intermediates at physiological ionic strength enables future exploration of how aspects of the cellular environment, like for example involvement of chaperones, affect these species.
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Affiliation(s)
- Joseline A Houwman
- Laboratory of Biochemistry, Wageningen University, Stippeneng 4, 6708 WE Wageningen, The Netherlands.
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7
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Kovachev PS, Banerjee D, Rangel LP, Eriksson J, Pedrote MM, Martins-Dinis MMDC, Edwards K, Cordeiro Y, Silva JL, Sanyal S. Distinct modulatory role of RNA in the aggregation of the tumor suppressor protein p53 core domain. J Biol Chem 2017; 292:9345-9357. [PMID: 28420731 DOI: 10.1074/jbc.m116.762096] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Revised: 04/12/2017] [Indexed: 01/05/2023] Open
Abstract
Inactivation of the tumor suppressor protein p53 by mutagenesis, chemical modification, protein-protein interaction, or aggregation has been associated with different human cancers. Although DNA is the typical substrate of p53, numerous studies have reported p53 interactions with RNA. Here, we have examined the effects of RNA of varied sequence, length, and origin on the mechanism of aggregation of the core domain of p53 (p53C) using light scattering, intrinsic fluorescence, transmission electron microscopy, thioflavin-T binding, seeding, and immunoblot assays. Our results are the first to demonstrate that RNA can modulate the aggregation of p53C and full-length p53. We found bimodal behavior of RNA in p53C aggregation. A low RNA:protein ratio (∼1:50) facilitates the accumulation of large amorphous aggregates of p53C. By contrast, at a high RNA:protein ratio (≥1:8), the amorphous aggregation of p53C is clearly suppressed. Instead, amyloid p53C oligomers are formed that can act as seeds nucleating de novo aggregation of p53C. We propose that structured RNAs prevent p53C aggregation through surface interaction and play a significant role in the regulation of the tumor suppressor protein.
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Affiliation(s)
- Petar Stefanov Kovachev
- From the Department of Cell and Molecular Biology, Uppsala University, Uppsala, Box-596, 75124, Sweden
| | - Debapriya Banerjee
- From the Department of Cell and Molecular Biology, Uppsala University, Uppsala, Box-596, 75124, Sweden
| | - Luciana Pereira Rangel
- Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, 21941-902, Brazil
| | - Jonny Eriksson
- Department of Chemistry, Uppsala University, Uppsala, 75124, Sweden, and
| | - Murilo M Pedrote
- Instituto de Bioquímica Médica Leopoldo de Meis, Instituto Nacional de Ciência Tecnologia de Biologia Estrutural e Bioimagem, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| | - Mafalda Maria D C Martins-Dinis
- Instituto de Bioquímica Médica Leopoldo de Meis, Instituto Nacional de Ciência Tecnologia de Biologia Estrutural e Bioimagem, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| | - Katarina Edwards
- Department of Chemistry, Uppsala University, Uppsala, 75124, Sweden, and
| | - Yraima Cordeiro
- Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, 21941-902, Brazil
| | - Jerson L Silva
- Instituto de Bioquímica Médica Leopoldo de Meis, Instituto Nacional de Ciência Tecnologia de Biologia Estrutural e Bioimagem, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| | - Suparna Sanyal
- From the Department of Cell and Molecular Biology, Uppsala University, Uppsala, Box-596, 75124, Sweden,
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8
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Sequestration of Ribosome during Protein Aggregate Formation: Contribution of ribosomal RNA. Sci Rep 2017; 7:42017. [PMID: 28169307 PMCID: PMC5294636 DOI: 10.1038/srep42017] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Accepted: 01/06/2017] [Indexed: 12/21/2022] Open
Abstract
An understanding of the mechanisms underlying protein aggregation and cytotoxicity of the protein aggregates is crucial in the prevention of several diseases in humans. Ribosome, the cellular protein synthesis machine is capable of acting as a protein folding modulator. The peptidyltransferase center residing in the domain V of large ribosomal subunit 23S rRNA is the centre for the protein folding ability of the ribosome and is also the cellular target of several antiprion compounds. Our in vitro studies unexpectedly reveal that the partial unfolding or aggregation of lysozyme under reducing conditions in presence of the ribosome can induce aggregation of ribosomal components. Electrostatic interactions complemented by specific rRNA-protein interaction drive the ribosome-protein aggregation process. Under similar conditions the rRNA, especially the large subunit rRNA and in vitro transcribed RNA corresponding to domain V of 23S rRNA (bDV RNA) stimulates lysozyme aggregation leading to RNA-protein aggregate formation. Protein aggregation during the refolding of non-disulfide containing protein BCAII at high concentrations also induces ribosome aggregation. BCAII aggregation was also stimulated in presence of the large subunit rRNA. Our observations imply that the specific sequestration of the translation machine by aggregating proteins might contribute to their cytotoxicity.
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9
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Blondel M, Soubigou F, Evrard J, Nguyen PH, Hasin N, Chédin S, Gillet R, Contesse MA, Friocourt G, Stahl G, Jones GW, Voisset C. Protein Folding Activity of the Ribosome is involved in Yeast Prion Propagation. Sci Rep 2016; 6:32117. [PMID: 27633137 PMCID: PMC5025663 DOI: 10.1038/srep32117] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 08/02/2016] [Indexed: 11/09/2022] Open
Abstract
6AP and GA are potent inhibitors of yeast and mammalian prions and also specific inhibitors of PFAR, the protein-folding activity borne by domain V of the large rRNA of the large subunit of the ribosome. We therefore explored the link between PFAR and yeast prion [PSI(+)] using both PFAR-enriched mutants and site-directed methylation. We demonstrate that PFAR is involved in propagation and de novo formation of [PSI(+)]. PFAR and the yeast heat-shock protein Hsp104 partially compensate each other for [PSI(+)] propagation. Our data also provide insight into new functions for the ribosome in basal thermotolerance and heat-shocked protein refolding. PFAR is thus an evolutionarily conserved cell component implicated in the prion life cycle, and we propose that it could be a potential therapeutic target for human protein misfolding diseases.
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Affiliation(s)
- Marc Blondel
- Inserm UMR 1078, Université de Bretagne Occidentale, Faculté de Médecine et des Sciences de la Santé; Etablissement Français du Sang (EFS) Bretagne; CHRU Brest, Hôpital Morvan, Laboratoire de Génétique Moléculaire, Brest, France
| | - Flavie Soubigou
- Inserm UMR 1078, Université de Bretagne Occidentale, Faculté de Médecine et des Sciences de la Santé; Etablissement Français du Sang (EFS) Bretagne; CHRU Brest, Hôpital Morvan, Laboratoire de Génétique Moléculaire, Brest, France
| | - Justine Evrard
- Inserm UMR 1078, Université de Bretagne Occidentale, Faculté de Médecine et des Sciences de la Santé; Etablissement Français du Sang (EFS) Bretagne; CHRU Brest, Hôpital Morvan, Laboratoire de Génétique Moléculaire, Brest, France
| | - Phu hai Nguyen
- Inserm UMR 1078, Université de Bretagne Occidentale, Faculté de Médecine et des Sciences de la Santé; Etablissement Français du Sang (EFS) Bretagne; CHRU Brest, Hôpital Morvan, Laboratoire de Génétique Moléculaire, Brest, France
| | - Naushaba Hasin
- Yeast Genetics Laboratory, Department of Biology, Maynooth University, Maynooth, County Kildare, Ireland
| | - Stéphane Chédin
- Institute for Integrative Biology of the Cell (I2BC), UMR 9198, CEA, CNRS, Université Paris-Sud, CEA/Saclay, SBIGeM, Gif-sur-Yvette, France
| | - Reynald Gillet
- Université de Rennes 1, CNRS UMR 6290 IGDR, Translation and Folding Team, Rennes, France
| | - Marie-Astrid Contesse
- Inserm UMR 1078, Université de Bretagne Occidentale, Faculté de Médecine et des Sciences de la Santé; Etablissement Français du Sang (EFS) Bretagne; CHRU Brest, Hôpital Morvan, Laboratoire de Génétique Moléculaire, Brest, France
| | - Gaëlle Friocourt
- Inserm UMR 1078, Université de Bretagne Occidentale, Faculté de Médecine et des Sciences de la Santé; Etablissement Français du Sang (EFS) Bretagne; CHRU Brest, Hôpital Morvan, Laboratoire de Génétique Moléculaire, Brest, France
| | - Guillaume Stahl
- Laboratoire de Biologie Moléculaire Eucaryotes, CNRS, Université de Toulouse, Toulouse, France
| | - Gary W. Jones
- Yeast Genetics Laboratory, Department of Biology, Maynooth University, Maynooth, County Kildare, Ireland
| | - Cécile Voisset
- Inserm UMR 1078, Université de Bretagne Occidentale, Faculté de Médecine et des Sciences de la Santé; Etablissement Français du Sang (EFS) Bretagne; CHRU Brest, Hôpital Morvan, Laboratoire de Génétique Moléculaire, Brest, France
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10
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Chakraborty B, Bhakta S, Sengupta J. Mechanistic Insight into the Reactivation of BCAII Enzyme from Denatured and Molten Globule States by Eukaryotic Ribosomes and Domain V rRNAs. PLoS One 2016; 11:e0153928. [PMID: 27099964 PMCID: PMC4839638 DOI: 10.1371/journal.pone.0153928] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2015] [Accepted: 04/06/2016] [Indexed: 12/29/2022] Open
Abstract
In all life forms, decoding of messenger-RNA into polypeptide chain is accomplished by the ribosome. Several protein chaperones are known to bind at the exit of ribosomal tunnel to ensure proper folding of the nascent chain by inhibiting their premature folding in the densely crowded environment of the cell. However, accumulating evidence suggests that ribosome may play a chaperone role in protein folding events in vitro. Ribosome-mediated folding of denatured proteins by prokaryotic ribosomes has been studied extensively. The RNA-assisted chaperone activity of the prokaryotic ribosome has been attributed to the domain V, a span of 23S rRNA at the intersubunit side of the large subunit encompassing the Peptidyl Transferase Centre. Evidently, this functional property of ribosome is unrelated to the nascent chain protein folding at the exit of the ribosomal tunnel. Here, we seek to scrutinize whether this unique function is conserved in a primitive kinetoplastid group of eukaryotic species Leishmania donovani where the ribosome structure possesses distinct additional features and appears markedly different compared to other higher eukaryotic ribosomes. Bovine Carbonic Anhydrase II (BCAII) enzyme was considered as the model protein. Our results manifest that domain V of the large subunit rRNA of Leishmania ribosomes preserves chaperone activity suggesting that ribosome-mediated protein folding is, indeed, a conserved phenomenon. Further, we aimed to investigate the mechanism underpinning the ribosome-assisted protein reactivation process. Interestingly, the surface plasmon resonance binding analyses exhibit that rRNA guides productive folding by directly interacting with molten globule-like states of the protein. In contrast, native protein shows no notable affinity to the rRNA. Thus, our study not only confirms conserved, RNA-mediated chaperoning role of ribosome but also provides crucial insight into the mechanism of the process.
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Affiliation(s)
- Biprashekhar Chakraborty
- Structural Biology & Bio-Informatics Division, Indian Institute of Chemical Biology (Council of Scientific & Industrial Research), 4, Raja S.C. Mullick Road, Kolkata, 700 032, India
| | - Sayan Bhakta
- Structural Biology & Bio-Informatics Division, Indian Institute of Chemical Biology (Council of Scientific & Industrial Research), 4, Raja S.C. Mullick Road, Kolkata, 700 032, India
| | - Jayati Sengupta
- Structural Biology & Bio-Informatics Division, Indian Institute of Chemical Biology (Council of Scientific & Industrial Research), 4, Raja S.C. Mullick Road, Kolkata, 700 032, India
- * E-mail:
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11
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Docter BE, Horowitz S, Gray MJ, Jakob U, Bardwell JCA. Do nucleic acids moonlight as molecular chaperones? Nucleic Acids Res 2016; 44:4835-45. [PMID: 27105849 PMCID: PMC4889950 DOI: 10.1093/nar/gkw291] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 04/08/2016] [Indexed: 01/17/2023] Open
Abstract
Organisms use molecular chaperones to combat the unfolding and aggregation of proteins. While protein chaperones have been widely studied, here we demonstrate that DNA and RNA exhibit potent chaperone activity in vitro Nucleic acids suppress the aggregation of classic chaperone substrates up to 300-fold more effectively than the protein chaperone GroEL. Additionally, RNA cooperates with the DnaK chaperone system to refold purified luciferase. Our findings reveal a possible new role for nucleic acids within the cell: that nucleic acids directly participate in maintaining proteostasis by preventing protein aggregation.
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Affiliation(s)
- Brianne E Docter
- Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, MI 48109, USA
| | - Scott Horowitz
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA Howard Hughes Medical Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Michael J Gray
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Ursula Jakob
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - James C A Bardwell
- Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, MI 48109, USA Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA Howard Hughes Medical Institute, University of Michigan, Ann Arbor, MI 48109, USA
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12
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Rajabi K, Reuther J, Deuerling E, Radford SE, Ashcroft AE. A comparison of the folding characteristics of free and ribosome-tethered polypeptide chains using limited proteolysis and mass spectrometry. Protein Sci 2015; 24:1282-91. [PMID: 25970093 PMCID: PMC4534179 DOI: 10.1002/pro.2702] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Revised: 04/27/2015] [Accepted: 04/29/2015] [Indexed: 11/15/2022]
Abstract
The kinetics and thermodynamics of protein folding are commonly studied in vitro by denaturing/renaturing intact protein sequences. How these folding mechanisms relate to de novo folding that occurs as the nascent polypeptide emerges from the ribosome is much less well understood. Here, we have employed limited proteolysis followed by mass spectrometry analyses to compare directly free and ribosome-tethered polypeptide chains of the Src-homology 3 (SH3) domain and its unfolded variant, SH3-m10. The disordered variant was found to undergo faster proteolysis than SH3. Furthermore, the trypsin cleavage patterns observed show minor, but significant, differences for the free and ribosome-bound nascent chains, with significantly fewer tryptic peptides detected in the presence of ribosome. The results highlight the utility of limited proteolysis coupled with mass spectrometry for the structural analysis of these complex systems, and pave the way for detailed future analyses by combining this technique with chemical labeling methods (for example, hydrogen-deuterium exchange, photochemical oxidation) to analyze protein folding in real time, including in the presence of additional ribosome-associated factors.
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Affiliation(s)
- Khadijeh Rajabi
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Julia Reuther
- Department of Biology, University of Konstanz, 78457, Konstanz, Germany
| | - Elke Deuerling
- Department of Biology, University of Konstanz, 78457, Konstanz, Germany
| | - Sheena E Radford
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Alison E Ashcroft
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
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