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Brázdovič F, Brejová B, Siváková B, Baráth P, Kerák F, Hodorová V, Vinař T, Tomáška Ľ, Nosek J. Reduction of Ribosomal Expansion Segments in Yeast Species of the Magnusiomyces/Saprochaete Clade. Genome Biol Evol 2024; 16:evae173. [PMID: 39119893 PMCID: PMC11342254 DOI: 10.1093/gbe/evae173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 06/25/2024] [Accepted: 08/01/2024] [Indexed: 08/10/2024] Open
Abstract
Ribosomes are ribonucleoprotein complexes highly conserved across all domains of life. The size differences of ribosomal RNAs (rRNAs) can be mainly attributed to variable regions termed expansion segments (ESs) protruding out from the ribosomal surface. The ESs were found to be involved in a range of processes including ribosome biogenesis and maturation, translation, and co-translational protein modification. Here, we analyze the rRNAs of the yeasts from the Magnusiomyces/Saprochaete clade belonging to the basal lineages of the subphylum Saccharomycotina. We find that these yeasts are missing more than 400 nt from the 25S rRNA and 150 nt from the 18S rRNAs when compared to their canonical counterparts in Saccharomyces cerevisiae. The missing regions mostly map to ESs, thus representing a shift toward a minimal rRNA structure. Despite the structural changes in rRNAs, we did not identify dramatic alterations in the ribosomal protein inventories. We also show that the size-reduced rRNAs are not limited to the species of the Magnusiomyces/Saprochaete clade, indicating that the shortening of ESs happened independently in several other lineages of the subphylum Saccharomycotina.
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Affiliation(s)
- Filip Brázdovič
- Faculty of Natural Sciences, Comenius University Bratislava, Bratislava, Slovakia
- Laboratory of Regulation of Gene Expression, Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Broňa Brejová
- Faculty of Mathematics, Physics, and Informatics, Comenius University Bratislava, Bratislava, Slovakia
| | - Barbara Siváková
- Slovak Academy of Sciences, Institute of Chemistry, Bratislava, Slovakia
| | - Peter Baráth
- Slovak Academy of Sciences, Institute of Chemistry, Bratislava, Slovakia
| | - Filip Kerák
- Faculty of Mathematics, Physics, and Informatics, Comenius University Bratislava, Bratislava, Slovakia
| | - Viktória Hodorová
- Faculty of Natural Sciences, Comenius University Bratislava, Bratislava, Slovakia
| | - Tomáš Vinař
- Faculty of Mathematics, Physics, and Informatics, Comenius University Bratislava, Bratislava, Slovakia
| | - Ľubomír Tomáška
- Faculty of Natural Sciences, Comenius University Bratislava, Bratislava, Slovakia
| | - Jozef Nosek
- Faculty of Natural Sciences, Comenius University Bratislava, Bratislava, Slovakia
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2
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Rajasekaran N, Kaiser CM. Navigating the complexities of multi-domain protein folding. Curr Opin Struct Biol 2024; 86:102790. [PMID: 38432063 DOI: 10.1016/j.sbi.2024.102790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 02/11/2024] [Accepted: 02/12/2024] [Indexed: 03/05/2024]
Abstract
Proteome complexity has expanded tremendously over evolutionary time, enabling biological diversification. Much of this complexity is achieved by combining a limited set of structural units into long polypeptides. This widely used evolutionary strategy poses challenges for folding of the resulting multi-domain proteins. As a consequence, their folding differs from that of small single-domain proteins, which generally fold quickly and reversibly. Co-translational processes and chaperone interactions are important aspects of multi-domain protein folding. In this review, we discuss some of the recent experimental progress toward understanding these processes.
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Affiliation(s)
| | - Christian M Kaiser
- Department of Biology, Johns Hopkins University, Baltimore, MD, United States; Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, Netherlands.
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3
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Ziegelhoffer T, Verma AK, Delewski W, Schilke BA, Hill PM, Pitek M, Marszalek J, Craig EA. NAC and Zuotin/Hsp70 chaperone systems coexist at the ribosome tunnel exit in vivo. Nucleic Acids Res 2024; 52:3346-3357. [PMID: 38224454 PMCID: PMC11014269 DOI: 10.1093/nar/gkae005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 12/23/2023] [Accepted: 01/02/2024] [Indexed: 01/16/2024] Open
Abstract
The area surrounding the tunnel exit of the 60S ribosomal subunit is a hub for proteins involved in maturation and folding of emerging nascent polypeptide chains. How different factors vie for positioning at the tunnel exit in the complex cellular environment is not well understood. We used in vivo site-specific cross-linking to approach this question, focusing on two abundant factors-the nascent chain-associated complex (NAC) and the Hsp70 chaperone system that includes the J-domain protein co-chaperone Zuotin. We found that NAC and Zuotin can cross-link to each other at the ribosome, even when translation initiation is inhibited. Positions yielding NAC-Zuotin cross-links indicate that when both are present the central globular domain of NAC is modestly shifted from the mutually exclusive position observed in cryogenic electron microscopy analysis. Cross-linking results also suggest that, even in NAC's presence, Hsp70 can situate in a manner conducive for productive nascent chain interaction-with the peptide binding site at the tunnel exit and the J-domain of Zuotin appropriately positioned to drive stabilization of nascent chain binding. Overall, our results are consistent with the idea that, in vivo, the NAC and Hsp70 systems can productively position on the ribosome simultaneously.
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Affiliation(s)
- Thomas Ziegelhoffer
- Department of Biochemistry, University of Wisconsin—Madison, Madison, WI 53726, USA
| | - Amit K Verma
- Department of Biochemistry, University of Wisconsin—Madison, Madison, WI 53726, USA
| | - Wojciech Delewski
- Department of Biochemistry, University of Wisconsin—Madison, Madison, WI 53726, USA
| | - Brenda A Schilke
- Department of Biochemistry, University of Wisconsin—Madison, Madison, WI 53726, USA
| | - Paige M Hill
- Department of Biochemistry, University of Wisconsin—Madison, Madison, WI 53726, USA
| | - Marcin Pitek
- Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Gdansk 80-307, Poland
| | - Jaroslaw Marszalek
- Department of Biochemistry, University of Wisconsin—Madison, Madison, WI 53726, USA
- Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Gdansk 80-307, Poland
| | - Elizabeth A Craig
- Department of Biochemistry, University of Wisconsin—Madison, Madison, WI 53726, USA
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Yan Y, Yang M, Jiao Y, Li L, Liu Z, Shi J, Shen Z, Peng G. Drug screening identified that handelin inhibits feline calicivirus infection by inhibiting HSP70 expression in vitro. J Gen Virol 2024; 105. [PMID: 38175184 DOI: 10.1099/jgv.0.001936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2024] Open
Abstract
Feline calicivirus (FCV) is considered one of the major pathogens of cats worldwide and causes upper respiratory tract disease in all cats. In some cats, infection is by a highly virulent strain of FCV (vs.-FCV), which can cause severe and fatal systemic disease symptoms. At present, few antiviral drugs are approved for clinical treatment against FCV. Therefore, there is an imminent need for effective FCV antiviral agents. Here, we used observed a cytopathic effect (CPE) assay to screen 1746 traditional Chinese medicine monomer compounds and found one that can effectively inhibit FCV replication, namely, handelin, with an effective concentration (EC50) value of approximately 2.5 µM. Further study showed that handelin inhibits FCV replication via interference with heat shock protein 70 (HSP70), which is a crucial host factor and plays a positive role in regulating viral replication. Moreover, handelin and HSP70 inhibitors have broad-spectrum antiviral activity. These findings indicate that handelin is a potential candidate for the treatment of FCV infection and that HSP70 may be an important drug target.
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Affiliation(s)
- Yuanyuan Yan
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, PR China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Cooperative Innovation Center for Sustainable Pig Production, Wuhan, PR China
| | - Mengfang Yang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, PR China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Cooperative Innovation Center for Sustainable Pig Production, Wuhan, PR China
| | - Yuzhou Jiao
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, PR China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Cooperative Innovation Center for Sustainable Pig Production, Wuhan, PR China
| | - Lisha Li
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, PR China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Cooperative Innovation Center for Sustainable Pig Production, Wuhan, PR China
| | - Zirui Liu
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, PR China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Cooperative Innovation Center for Sustainable Pig Production, Wuhan, PR China
| | - Jiale Shi
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, PR China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Cooperative Innovation Center for Sustainable Pig Production, Wuhan, PR China
| | - Zhou Shen
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, PR China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Cooperative Innovation Center for Sustainable Pig Production, Wuhan, PR China
| | - Guiqing Peng
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, PR China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Cooperative Innovation Center for Sustainable Pig Production, Wuhan, PR China
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Chen YJ, Cheng SY, Liu CH, Tsai WC, Wu HH, Huang MD. Exploration of the truncated cytosolic Hsp70 in plants - unveiling the diverse T1 lineage and the conserved T2 lineage. FRONTIERS IN PLANT SCIENCE 2023; 14:1279540. [PMID: 38034583 PMCID: PMC10687569 DOI: 10.3389/fpls.2023.1279540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Accepted: 10/18/2023] [Indexed: 12/02/2023]
Abstract
The 70-kDa heat shock proteins (Hsp70s) are chaperone proteins involved in protein folding processes. Truncated Hsp70 (Hsp70T) refers to the variant lacking a conserved C-terminal motif, which is crucial for co-chaperone interactions or protein retention. Despite their significance, the characteristics of Hsp70Ts in plants remain largely unexplored. In this study, we performed a comprehensive genome-wide analysis of 192 sequenced plant and green algae genomes to investigate the distribution and features of Hsp70Ts. Our findings unveil the widespread occurrence of Hsp70Ts across all four Hsp70 forms, including cytosolic, endoplasmic reticulum, mitochondrial, and chloroplast Hsp70s, with cytosolic Hsp70T being the most prevalent and abundant subtype. Cytosolic Hsp70T is characterized by two distinct lineages, referred to as T1 and T2. Among the investigated plant and green algae species, T1 genes were identified in approximately 60% of cases, showcasing a variable gene count ranging from one to several dozens. In contrast, T2 genes were prevalent across the majority of plant genomes, usually occurring in fewer than five gene copies per species. Sequence analysis highlights that the putative T1 proteins exhibit higher similarity to full-length cytosolic Hsp70s in comparison to T2 proteins. Intriguingly, the T2 lineage demonstrates a higher level of conservation within their protein sequences, whereas the T1 lineage presents a diverse range in the C-terminal and SBDα region, leading to categorization into four distinct subtypes. Furthermore, we have observed that T1-rich species characterized by the possession of 15 or more T1 genes exhibit an expansion of T1 genes into tandem gene clusters. The T1 gene clusters identified within the Laurales order display synteny with clusters found in a species of the Chloranthales order and another species within basal angiosperms, suggesting a conserved evolutionary relationship of T1 gene clusters among these plants. Additionally, T2 genes demonstrate distinct expression patterns in seeds and under heat stress, implying their potential roles in seed development and stress response.
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Affiliation(s)
- Yi-Jing Chen
- Department of Biological Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan
| | - Sou-Yu Cheng
- Department of Biological Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan
| | - Cheng-Han Liu
- Department of Biological Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan
| | - Wen-Chieh Tsai
- Institute of Tropical Plant Sciences and Microbiology, National Cheng Kung University, Tainan, Taiwan
| | - Hsin-Hsin Wu
- Department of Biological Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan
| | - Ming-Der Huang
- Department of Biological Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan
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Ciesielski SJ, Young C, Ciesielska EJ, Ciesielski GL. The Hsp70 and JDP proteins: Structure-function perspective on molecular chaperone activity. Enzymes 2023; 54:221-245. [PMID: 37945173 DOI: 10.1016/bs.enz.2023.07.008] [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: 11/12/2023]
Abstract
Proteins are the most structurally diverse cellular biomolecules that act as molecular machines driving essential activities of all living organisms. To be functional, most of the proteins need to fold into a specific three-dimensional structure, which on one hand should be stable enough to oppose disruptive conditions and on the other hand flexible enough to allow conformational dynamics necessary for their biological functions. This compromise between stability and dynamics makes proteins susceptible to stress-induced misfolding and aggregation. Moreover, the folding process itself is intrinsically prone to conformational errors. Molecular chaperones are proteins that mitigate folding defects and maintain the structural integrity of the cellular proteome. Promiscuous Hsp70 chaperones are central to these processes and their activity depends on the interaction with obligatory J-domain protein (JDP) partners. In this review, we discuss structural aspects of Hsp70s, JDPs, and their interaction in the context of biological activities.
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Affiliation(s)
- Szymon J Ciesielski
- Department of Chemistry and Biochemistry, University of North Florida, Jacksonville, FL, United States.
| | - Cameron Young
- Department of Chemistry and Biochemistry, University of North Florida, Jacksonville, FL, United States
| | - Elena J Ciesielska
- Department of Chemistry, Auburn University at Montgomery, Montgomery, AL, United States; Department of Biology, University of North Florida, Jacksonville, FL, United States
| | - Grzegorz L Ciesielski
- Department of Chemistry, Auburn University at Montgomery, Montgomery, AL, United States; Department of Biology, University of North Florida, Jacksonville, FL, United States
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Kišonaitė M, Wild K, Lapouge K, Gesé GV, Kellner N, Hurt E, Sinning I. Structural inventory of cotranslational protein folding by the eukaryotic RAC complex. Nat Struct Mol Biol 2023; 30:670-677. [PMID: 37081320 DOI: 10.1038/s41594-023-00973-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 03/20/2023] [Indexed: 04/22/2023]
Abstract
The challenge of nascent chain folding at the ribosome is met by the conserved ribosome-associated complex (RAC), which forms a chaperone triad with the Hsp70 protein Ssb in fungi, and consists of the non-canonical Hsp70 Ssz1 and the J domain protein Zuotin (Zuo1). Here we determine cryo-EM structures of Chaetomium thermophilum RAC bound to 80S ribosomes. RAC adopts two distinct conformations accommodating continuous ribosomal rotation by a flexible lever arm. It is held together by a tight interaction between the Ssz1 substrate-binding domain and the Zuo1 N terminus, and additional contacts between the Ssz1 nucleotide-binding domain and Zuo1 J- and Zuo1 homology domains, which form a rigid unit. The Zuo1 HPD motif conserved in J-proteins is masked in a non-canonical interaction by the Ssz1 nucleotide-binding domain, and allows the positioning of Ssb for activation by Zuo1. Overall, we provide the basis for understanding how RAC cooperates with Ssb in a dynamic nascent chain interaction and protein folding.
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Affiliation(s)
- Miglė Kišonaitė
- Heidelberg University Biochemistry Center (BZH), Heidelberg, Germany
| | - Klemens Wild
- Heidelberg University Biochemistry Center (BZH), Heidelberg, Germany
| | - Karine Lapouge
- Heidelberg University Biochemistry Center (BZH), Heidelberg, Germany
| | | | - Nikola Kellner
- Heidelberg University Biochemistry Center (BZH), Heidelberg, Germany
| | - Ed Hurt
- Heidelberg University Biochemistry Center (BZH), Heidelberg, Germany
| | - Irmgard Sinning
- Heidelberg University Biochemistry Center (BZH), Heidelberg, Germany.
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Morales-Polanco F, Lee JH, Barbosa NM, Frydman J. Cotranslational Mechanisms of Protein Biogenesis and Complex Assembly in Eukaryotes. Annu Rev Biomed Data Sci 2022; 5:67-94. [PMID: 35472290 PMCID: PMC11040709 DOI: 10.1146/annurev-biodatasci-121721-095858] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The formation of protein complexes is crucial to most biological functions. The cellular mechanisms governing protein complex biogenesis are not yet well understood, but some principles of cotranslational and posttranslational assembly are beginning to emerge. In bacteria, this process is favored by operons encoding subunits of protein complexes. Eukaryotic cells do not have polycistronic mRNAs, raising the question of how they orchestrate the encounter of unassembled subunits. Here we review the constraints and mechanisms governing eukaryotic co- and posttranslational protein folding and assembly, including the influence of elongation rate on nascent chain targeting, folding, and chaperone interactions. Recent evidence shows that mRNAs encoding subunits of oligomeric assemblies can undergo localized translation and form cytoplasmic condensates that might facilitate the assembly of protein complexes. Understanding the interplay between localized mRNA translation and cotranslational proteostasis will be critical to defining protein complex assembly in vivo.
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Affiliation(s)
| | - Jae Ho Lee
- Department of Biology, Stanford University, Stanford, California, USA;
| | - Natália M Barbosa
- Department of Biology, Stanford University, Stanford, California, USA;
| | - Judith Frydman
- Department of Biology, Stanford University, Stanford, California, USA;
- Department of Genetics, Stanford University, Stanford, California, USA
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Hassell D, Denney A, Singer E, Benson A, Roth A, Ceglowski J, Steingesser M, McMurray M. Chaperone Requirements for De Novo Folding of Saccharomyces cerevisiae Septins. Mol Biol Cell 2022; 33:ar111. [PMID: 35947497 DOI: 10.1091/mbc.e22-07-0262] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Polymers of septin protein complexes play cytoskeletal roles in eukaryotic cells. The specific subunit composition within complexes controls functions and higher-order structural properties. All septins have globular GTPase domains. The other eukaryotic cytoskeletal NTPases strictly require assistance from molecular chaperones of the cytosol, particularly the cage-like chaperonins, to fold into oligomerization-competent conformations. We previously identified cytosolic chaperones that bind septins and influence the oligomerization ability of septins carrying mutations linked to human disease, but it was unknown to what extent wild-type septins require chaperone assistance for their native folding. Here we use a combination of in vivo and in vitro approaches to demonstrate chaperone requirements for de novo folding and complex assembly by budding yeast septins. Individually purified septins adopted non-native conformations and formed non-native homodimers. In chaperonin- or Hsp70-deficient cells, septins folded slower and were unable to assemble post-translationally into native complexes. One septin, Cdc12, was so dependent on co-translational chaperonin assistance that translation failed without it. Our findings point to distinct translation elongation rates for different septins as a possible mechanism to direct a stepwise, co-translational assembly pathway in which general cytosolic chaperones act as key intermediaries.
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Affiliation(s)
- Daniel Hassell
- University of Colorado Anschutz Medical Campus, Aurora, CO 80045
| | - Ashley Denney
- University of Colorado Anschutz Medical Campus, Aurora, CO 80045
| | - Emily Singer
- University of Colorado Anschutz Medical Campus, Aurora, CO 80045
| | - Aleyna Benson
- University of Colorado Anschutz Medical Campus, Aurora, CO 80045
| | - Andrew Roth
- University of Colorado Anschutz Medical Campus, Aurora, CO 80045
| | - Julia Ceglowski
- University of Colorado Anschutz Medical Campus, Aurora, CO 80045
| | - Marc Steingesser
- University of Colorado Anschutz Medical Campus, Aurora, CO 80045
| | - Michael McMurray
- University of Colorado Anschutz Medical Campus, Aurora, CO 80045
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Structural remodeling of ribosome associated Hsp40-Hsp70 chaperones during co-translational folding. Nat Commun 2022; 13:3410. [PMID: 35701497 PMCID: PMC9197937 DOI: 10.1038/s41467-022-31127-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Accepted: 06/02/2022] [Indexed: 11/16/2022] Open
Abstract
Ribosome associated complex (RAC), an obligate heterodimer of HSP40 and HSP70 (Zuo1 and Ssz1 in yeast), is conserved in eukaryotes and functions as co-chaperone for another HSP70 (Ssb1/2 in yeast) to facilitate co-translational folding of nascent polypeptides. Many mechanistic details, such as the coordination of one HSP40 with two HSP70s and the dynamic interplay between RAC-Ssb and growing nascent chains, remain unclear. Here, we report three sets of structures of RAC-containing ribosomal complexes isolated from Saccharomyces cerevisiae. Structural analyses indicate that RAC on the nascent-chain-free ribosome is in an autoinhibited conformation, and in the presence of a nascent chain at the peptide tunnel exit (PTE), RAC undergoes large-scale structural remodeling to make Zuo1 J-Domain more accessible to Ssb. Our data also suggest a role of Zuo1 in orienting Ssb-SBD proximal to the PTE for easy capture of the substrate. Altogether, in accordance with previous data, our work suggests a sequence of structural remodeling events for RAC-Ssb during co-translational folding, triggered by the binding and passage of growing nascent chain from one to another. Ribosome associated complex (RAC)- HSP70 (Ssb in yeast) is a eukaryotic chaperone system involved in co-translational folding. Here, authors report structures of RAC-containing ribosomal complexes, which suggest a working model for the dynamic actions of RAC-Ssb during the process.
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The Astonishing Large Family of HSP40/DnaJ Proteins Existing in Leishmania. Genes (Basel) 2022; 13:genes13050742. [PMID: 35627127 PMCID: PMC9141911 DOI: 10.3390/genes13050742] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 04/14/2022] [Accepted: 04/21/2022] [Indexed: 02/04/2023] Open
Abstract
Abrupt environmental changes are faced by Leishmania parasites during transmission from a poikilothermic insect vector to a warm-blooded host. Adaptation to harsh environmental conditions, such as nutrient deprivation, hypoxia, oxidative stress and heat shock needs to be accomplished by rapid reconfiguration of gene expression and remodeling of protein interaction networks. Chaperones play a central role in the maintenance of cellular homeostasis, and they are responsible for crucial tasks such as correct folding of nascent proteins, protein translocation across different subcellular compartments, avoiding protein aggregates and elimination of damaged proteins. Nearly one percent of the gene content in the Leishmania genome corresponds to members of the HSP40 family, a group of proteins that assist HSP70s in a variety of cellular functions. Despite their expected relevance in the parasite biology and infectivity, little is known about their functions or partnership with the different Leishmania HSP70s. Here, we summarize the structural features of the 72 HSP40 proteins encoded in the Leishmania infantum genome and their classification into four categories. A review of proteomic data, together with orthology analyses, allow us to postulate cellular locations and possible functional roles for some of them. A detailed study of the members of this family would provide valuable information and opportunities for drug discovery and improvement of current treatments against leishmaniasis.
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