1
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Gupta MN, Uversky VN. Protein structure-function continuum model: Emerging nexuses between specificity, evolution, and structure. Protein Sci 2024; 33:e4968. [PMID: 38532700 DOI: 10.1002/pro.4968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2023] [Revised: 02/18/2024] [Accepted: 03/05/2024] [Indexed: 03/28/2024]
Abstract
The rationale for replacing the old binary of structure-function with the trinity of structure, disorder, and function has gained considerable ground in recent years. A continuum model based on the expanded form of the existing paradigm can now subsume importance of both conformational flexibility and intrinsic disorder in protein function. The disorder is actually critical for understanding the protein-protein interactions in many regulatory processes, formation of membrane-less organelles, and our revised notions of specificity as amply illustrated by moonlighting proteins. While its importance in formation of amyloids and function of prions is often discussed, the roles of intrinsic disorder in infectious diseases and protein function under extreme conditions are also becoming clear. This review is an attempt to discuss how our current understanding of protein function, specificity, and evolution fit better with the continuum model. This integration of structure and disorder under a single model may bring greater clarity in our continuing quest for understanding proteins and molecular mechanisms of their functionality.
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Affiliation(s)
- Munishwar Nath Gupta
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology, New Delhi, India
| | - Vladimir N Uversky
- Department of Molecular Medicine and USF Health Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
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2
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Lee J, Ryu B, Kim T, Kim KK. Cryo-EM structure of a 16.5-kDa small heat-shock protein from Methanocaldococcus jannaschii. Int J Biol Macromol 2024; 258:128763. [PMID: 38103675 DOI: 10.1016/j.ijbiomac.2023.128763] [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: 10/23/2023] [Revised: 12/07/2023] [Accepted: 12/11/2023] [Indexed: 12/19/2023]
Abstract
The small heat-shock protein (sHSP) from the archaea Methanocaldococcus jannaschii, MjsHSP16.5, functions as a broad substrate ATP-independent holding chaperone protecting misfolded proteins from aggregation under stress conditions. This protein is the first sHSP characterized by X-ray crystallography, thereby contributing significantly to our understanding of sHSPs. However, despite numerous studies assessing its functions and structures, the precise arrangement of the N-terminal domains (NTDs) within this sHSP cage remains elusive. Here we present the cryo-electron microscopy (cryo-EM) structure of MjsHSP16.5 at 2.49-Å resolution. The subunits of MjsHSP16.5 in the cryo-EM structure exhibit lesser compaction compared to their counterparts in the crystal structure. This structural feature holds particular significance in relation to the biophysical properties of MjsHSP16.5, suggesting a close resemblance to this sHSP native state. Additionally, our cryo-EM structure unveils the density of residues 24-33 within the NTD of MjsHSP16.5, a feature that typically remains invisible in the majority of its crystal structures. Notably, these residues show a propensity to adopt a β-strand conformation and engage in antiparallel interactions with strand β1, both intra- and inter-subunit modes. These structural insights are corroborated by structural predictions, disulfide bond cross-linking studies of Cys-substitution mutants, and protein disaggregation assays. A comprehensive understanding of the structural features of MjsHSP16.5 expectedly holds the potential to inspire a wide range of interdisciplinary applications, owing to the renowned versatility of this sHSP as a nanoscale protein platform.
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Affiliation(s)
- Joohyun Lee
- Department of Precision Medicine, Graduate School of Basic Medical Science (GSBMS), Institute for Antimicrobial Resistance Research and Therapeutics, Sungkyunkwan University School of Medicine, Suwon 16419, Republic of Korea
| | - Bumhan Ryu
- Research Solution Center, Institute for Basic Science (IBS), Daejeon 34126, Republic of Korea
| | - Truc Kim
- Department of Precision Medicine, Graduate School of Basic Medical Science (GSBMS), Institute for Antimicrobial Resistance Research and Therapeutics, Sungkyunkwan University School of Medicine, Suwon 16419, Republic of Korea.
| | - Kyeong Kyu Kim
- Department of Precision Medicine, Graduate School of Basic Medical Science (GSBMS), Institute for Antimicrobial Resistance Research and Therapeutics, Sungkyunkwan University School of Medicine, Suwon 16419, Republic of Korea.
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3
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Wang C, Teng L, Liu ZS, Kamalova A, McMenimen KA. HspB5 Chaperone Structure and Activity Are Modulated by Chemical-Scale Interactions in the ACD Dimer Interface. Int J Mol Sci 2023; 25:471. [PMID: 38203641 PMCID: PMC10778692 DOI: 10.3390/ijms25010471] [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] [Received: 11/20/2023] [Revised: 12/24/2023] [Accepted: 12/27/2023] [Indexed: 01/12/2024] Open
Abstract
Small heat shock proteins (sHsps) are a family of ATP-independent molecular chaperones that function as "holdases" and prevent protein aggregation due to changes in temperature, pH, or oxidation state. sHsps have a conserved α-crystallin domain (ACD), which forms the dimer building block, flanked by variable N- and C-terminal regions. sHsps populate various oligomeric states as a function of their sequestrase activity, and these dynamic structural features allow the proteins to interact with a plethora of cellular substrates. However, the molecular mechanisms of their dynamic conformational assembly and the interactions with various substrates remains unclear. Therefore, it is important to gain insight into the underlying physicochemical properties that influence sHsp structure in an effort to understand their mechanism(s) of action. We evaluated several disease-relevant mutations, D109A, F113Y, R116C, R120G, and R120C, in the ACD of HspB5 for changes to in vitro chaperone activity relative to that of wildtype. Structural characteristics were also evaluated by ANS fluorescence and CD spectroscopy. Our results indicated that mutation Y113F is an efficient holdase, while D109A and R120G, which are found in patients with myofibrillar myopathy and cataracts, respectively, exhibit a large reduction in holdase activity in a chaperone-like light-scattering assay, which indicated alterations in substrate-sHsp interactions. The extent of the reductions in chaperone activities are different among the mutants and specific to the substrate protein, suggesting that while sHsps are able to interact with many substrates, specific interactions provide selectivity for some substrates compared to others. This work is consistent with a model for chaperone activity where key electrostatic interactions in the sHsp dimer provide structural stability and influence both higher-order sHsp interactions and facilitate interactions with substrate proteins that define chaperone holdase activity.
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Affiliation(s)
- Chenwei Wang
- Program in Biochemistry, Mount Holyoke College, South Hadley, MA 01075, USA; (C.W.); (L.T.); (Z.S.L.)
| | - Lilong Teng
- Program in Biochemistry, Mount Holyoke College, South Hadley, MA 01075, USA; (C.W.); (L.T.); (Z.S.L.)
| | - Zhiyan Silvia Liu
- Program in Biochemistry, Mount Holyoke College, South Hadley, MA 01075, USA; (C.W.); (L.T.); (Z.S.L.)
| | - Aichurok Kamalova
- Program in Neuroscience and Behavior, Mount Holyoke College, South Hadley, MA 01075, USA;
| | - Kathryn A. McMenimen
- Program in Biochemistry, Mount Holyoke College, South Hadley, MA 01075, USA; (C.W.); (L.T.); (Z.S.L.)
- Program in Neuroscience and Behavior, Mount Holyoke College, South Hadley, MA 01075, USA;
- Department of Chemistry, Mount Holyoke College, South Hadley, MA 01075, USA
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4
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Esmaeilzadeh A, Mohammadi V, Elahi R, Rezakhani N. The role of heat shock proteins (HSPs) in type 2 diabetes mellitus pathophysiology. J Diabetes Complications 2023; 37:108564. [PMID: 37852076 DOI: 10.1016/j.jdiacomp.2023.108564] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2023] [Revised: 07/05/2023] [Accepted: 07/21/2023] [Indexed: 10/20/2023]
Abstract
Type 2 diabetes mellitus (T2DM) is a metabolic disorder characterized by sustained hyperglycemia caused by impaired insulin signaling and secretion. Metabolic stress, caused by an inappropriate diet, is one of the major hallmarks provoking inflammation, endoplasmic reticulum (ER) stress, and mitochondrial dysfunction. Heat shock proteins (HSPs) are a group of highly conserved proteins that have a crucial role in chaperoning damaged and misfolded proteins to avoid disruption of cellular homeostasis under stress conditions. To do this, HSPs interact with diverse intra-and extracellular pathways among which are the insulin signaling, insulin secretion, and apoptosis pathways. Therefore, HSP dysfunction, e.g. HSP70, may lead to disruption of the pathways responsible for insulin secretion and uptake. Consistently, the altered expression of other HSPs and genetic polymorphisms in HSP-producing genes in diabetic subjects has made HSPs hot research in T2DM. This paper provides a comprehensive overview of the role of different HSPs in T2DM pathogenesis, affected cellular pathways, and the potential therapeutic strategies targeting HSPs in T2DM.
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Affiliation(s)
- Abdolreza Esmaeilzadeh
- Department of Immunology, Zanjan University of Medical Sciences, Zanjan, Iran; Cancer Gene Therapy Research Center (CGRC), Zanjan University of Medical Sciences, Zanjan, Iran.
| | - Vahid Mohammadi
- School of Medicine, Zanjan University of Medical Sciences, Zanjan, Iran
| | - Reza Elahi
- School of Medicine, Zanjan University of Medical Sciences, Zanjan, Iran
| | - Negin Rezakhani
- School of Medicine, Zanjan University of Medical Sciences, Zanjan, Iran
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5
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Alderson TR, Pritišanac I, Kolarić Đ, Moses AM, Forman-Kay JD. Systematic identification of conditionally folded intrinsically disordered regions by AlphaFold2. Proc Natl Acad Sci U S A 2023; 120:e2304302120. [PMID: 37878721 PMCID: PMC10622901 DOI: 10.1073/pnas.2304302120] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Accepted: 08/30/2023] [Indexed: 10/27/2023] Open
Abstract
The AlphaFold Protein Structure Database contains predicted structures for millions of proteins. For the majority of human proteins that contain intrinsically disordered regions (IDRs), which do not adopt a stable structure, it is generally assumed that these regions have low AlphaFold2 confidence scores that reflect low-confidence structural predictions. Here, we show that AlphaFold2 assigns confident structures to nearly 15% of human IDRs. By comparison to experimental NMR data for a subset of IDRs that are known to conditionally fold (i.e., upon binding or under other specific conditions), we find that AlphaFold2 often predicts the structure of the conditionally folded state. Based on databases of IDRs that are known to conditionally fold, we estimate that AlphaFold2 can identify conditionally folding IDRs at a precision as high as 88% at a 10% false positive rate, which is remarkable considering that conditionally folded IDR structures were minimally represented in its training data. We find that human disease mutations are nearly fivefold enriched in conditionally folded IDRs over IDRs in general and that up to 80% of IDRs in prokaryotes are predicted to conditionally fold, compared to less than 20% of eukaryotic IDRs. These results indicate that a large majority of IDRs in the proteomes of human and other eukaryotes function in the absence of conditional folding, but the regions that do acquire folds are more sensitive to mutations. We emphasize that the AlphaFold2 predictions do not reveal functionally relevant structural plasticity within IDRs and cannot offer realistic ensemble representations of conditionally folded IDRs.
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Affiliation(s)
- T. Reid Alderson
- Department of Biochemistry, University of Toronto, Toronto, ONM5S 1A8, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ONM5S 1A8, Canada
| | - Iva Pritišanac
- Department of Cell and Systems Biology, University of Toronto, Toronto, ONM5S 35G, Canada
- Molecular Medicine Program, The Hospital for Sick Children, Toronto, ONM5G 0A4, Canada
- Department of Molecular Biology and Biochemistry, Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Medical University of Graz, Graz8010, Austria
| | - Đesika Kolarić
- Department of Molecular Biology and Biochemistry, Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Medical University of Graz, Graz8010, Austria
| | - Alan M. Moses
- Department of Cell and Systems Biology, University of Toronto, Toronto, ONM5S 35G, Canada
| | - Julie D. Forman-Kay
- Department of Biochemistry, University of Toronto, Toronto, ONM5S 1A8, Canada
- Molecular Medicine Program, The Hospital for Sick Children, Toronto, ONM5G 0A4, Canada
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6
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Mukherjee S, Vogl DP, Becker CFW. Site-Specific Glycation of Human Heat Shock Protein (Hsp27) Enhances Its Chaperone Activity. ACS Chem Biol 2023; 18:1760-1771. [PMID: 37449780 PMCID: PMC10442856 DOI: 10.1021/acschembio.3c00214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Accepted: 07/03/2023] [Indexed: 07/18/2023]
Abstract
Non-enzymatic posttranslational modifications are believed to affect at least 30% of human proteins, commonly termed glycation. Many of these modifications are implicated in various pathological conditions, e.g., cataract, diabetes, neurodegenerative diseases, and cancer. Chemical protein synthesis enables access to full-length proteins carrying site-specific modifications. One such modification, argpyrimidine (Apy), has been detected in human small heat shock protein Hsp27 and closely related proteins in patient-derived tissues. Thus far, studies have looked into only artificial mixtures of Apy modifications, and only one has analyzed Apy188. We were interested in understanding the impact of such individual Apy modifications on five different arginine sites within the crucial N-terminal domain of Hsp27. By combining protein semisynthesis with biochemical assays on semisynthetic Hsp27 analogues with single-point Apy modification at those sites, we have shown how a seemingly minimal modification within this region results in dramatically altered functional attributes.
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Affiliation(s)
- Somnath Mukherjee
- University
of Vienna, Faculty of Chemistry, Institute
of Biological Chemistry, Währinger Strasse 38, 1090 Vienna, Austria
| | - Dominik P. Vogl
- University
of Vienna, Faculty of Chemistry, Institute
of Biological Chemistry, Währinger Strasse 38, 1090 Vienna, Austria
- Vienna
Doctoral School in Chemistry, Währinger Strasse 42, 1090 Vienna, Austria
| | - Christian F. W. Becker
- University
of Vienna, Faculty of Chemistry, Institute
of Biological Chemistry, Währinger Strasse 38, 1090 Vienna, Austria
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7
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Lei T, Xiao Z, Bi W, Cai S, Yang Y, Du H. Targeting small heat shock proteins to degrade aggregates as a potential strategy in neurodegenerative diseases. Ageing Res Rev 2022; 82:101769. [PMID: 36283618 DOI: 10.1016/j.arr.2022.101769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 10/18/2022] [Accepted: 10/21/2022] [Indexed: 01/31/2023]
Abstract
Neurodegenerative diseases (NDs) are aging-related diseases that involve the death of neurons in the brain. Dysregulation of protein homeostasis leads to the production of toxic proteins or the formation of aggregates, which is the pathological basis of NDs. Small heat shock proteins (HSPB) is involved in the establishment of a protein quality control (PQC) system to maintain cellular homeostasis. HSPB can be secreted into the extracellular space and delivered by various routes, especially extracellular vehicles (EVs). HSPB plays an important role in influencing the aggregation phase of toxic proteins involved in heat shock transcription factor (HSF) regulation, oxidative stress, autophagy and apoptosis pathways. HSPB conferred neuroprotective effects by resisting toxic protein aggregation, reducing autophagy and reducing neuronal apoptosis. The HSPB treatment strategies, including targeted PQC system therapy and delivery of EVs-HSPB, can improve disease manifestations for NDs. This review aims to provide a comprehensive insight into the impact of HSPB in NDs and the feasibility of new technology to enhance HSPB expression and EVs-HSPB delivery for neurodegenerative disease.
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Affiliation(s)
- Tong Lei
- School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing 100083, China; Daxing Research Institute, University of Science and Technology Beijing, Beijing 100083, China
| | - Zhuangzhuang Xiao
- School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing 100083, China; Daxing Research Institute, University of Science and Technology Beijing, Beijing 100083, China
| | - Wangyu Bi
- School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing 100083, China; Daxing Research Institute, University of Science and Technology Beijing, Beijing 100083, China
| | - Shanglin Cai
- School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing 100083, China; Daxing Research Institute, University of Science and Technology Beijing, Beijing 100083, China
| | - Yanjie Yang
- School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing 100083, China; Daxing Research Institute, University of Science and Technology Beijing, Beijing 100083, China
| | - Hongwu Du
- School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing 100083, China; Daxing Research Institute, University of Science and Technology Beijing, Beijing 100083, China.
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8
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Gao H, He C, Hua R, Guo Y, Wang B, Liang C, Gao L, Shang H, Xu JD. Endoplasmic Reticulum Stress of Gut Enterocyte and Intestinal Diseases. Front Mol Biosci 2022; 9:817392. [PMID: 35402506 PMCID: PMC8988245 DOI: 10.3389/fmolb.2022.817392] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 01/19/2022] [Indexed: 12/21/2022] Open
Abstract
The endoplasmic reticulum, a vast reticular membranous network from the nuclear envelope to the plasma membrane responsible for the synthesis, maturation, and trafficking of a wide range of proteins, is considerably sensitive to changes in its luminal homeostasis. The loss of ER luminal homeostasis leads to abnormalities referred to as endoplasmic reticulum (ER) stress. Thus, the cell activates an adaptive response known as the unfolded protein response (UPR), a mechanism to stabilize ER homeostasis under severe environmental conditions. ER stress has recently been postulated as a disease research breakthrough due to its significant role in multiple vital cellular functions. This has caused numerous reports that ER stress-induced cell dysfunction has been implicated as an essential contributor to the occurrence and development of many diseases, resulting in them targeting the relief of ER stress. This review aims to outline the multiple molecular mechanisms of ER stress that can elucidate ER as an expansive, membrane-enclosed organelle playing a crucial role in numerous cellular functions with evident changes of several cells encountering ER stress. Alongside, we mainly focused on the therapeutic potential of ER stress inhibition in gastrointestinal diseases such as inflammatory bowel disease (IBD) and colorectal cancer. To conclude, we reviewed advanced research and highlighted future treatment strategies of ER stress-associated conditions.
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Affiliation(s)
- Han Gao
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Chengwei He
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Rongxuan Hua
- Department of Clinical Medicine, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Yuexin Guo
- Department of Oral Medicine, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Boya Wang
- Undergraduate Student of 2018 Eight Program of Clinical Medicine, Peking University Health Science Center, Beijing, China
| | - Chen Liang
- Department of Clinical Medicine, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Lei Gao
- Department of Biomedical Informatics, School of Biomedical Engineering, Capital Medical University, Beijing, China
| | - Hongwei Shang
- Experimental Center for Morphological Research Platform, Capital Medical University, Beijing, China
| | - Jing-Dong Xu
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
- *Correspondence: Jing-Dong Xu,
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9
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Van den Broek B, Wuyts C, Irobi J. Extracellular vesicle-associated small heat shock proteins as therapeutic agents in neurodegenerative diseases and beyond. Adv Drug Deliv Rev 2021; 179:114009. [PMID: 34673130 DOI: 10.1016/j.addr.2021.114009] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 09/11/2021] [Accepted: 10/12/2021] [Indexed: 12/12/2022]
Abstract
Increasing evidence points towards using extracellular vesicles (EVs) as a therapeutic strategy in neurodegenerative diseases such as multiple sclerosis, Parkinson's, and Alzheimer's disease. EVs are nanosized carriers that play an essential role in intercellular communication and cellular homeostasis by transporting an active molecular cargo, including a large variety of proteins. Recent publications demonstrate that small heat shock proteins (HSPBs) exhibit a beneficial role in neurodegenerative diseases. Moreover, it is defined that HSPBs target the autophagy and the apoptosis pathway, playing a prominent role in chaperone activity and cell survival. This review elaborates on the therapeutic potential of EVs and HSPBs, in particular HSPB1 and HSPB8, in neurodegenerative diseases. We conclude that EVs and HSPBs positively influence neuroinflammation, central nervous system (CNS) repair, and protein aggregation in CNS disorders. Moreover, we propose the use of HSPB-loaded EVs as advanced nanocarriers for the future development of neurodegenerative disease therapies.
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Affiliation(s)
- Bram Van den Broek
- Department of Immunology and Infection, Biomedical Research Institute, Hasselt University, Diepenbeek, Belgium
| | - Charlotte Wuyts
- Department of Immunology and Infection, Biomedical Research Institute, Hasselt University, Diepenbeek, Belgium
| | - Joy Irobi
- Department of Immunology and Infection, Biomedical Research Institute, Hasselt University, Diepenbeek, Belgium.
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10
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Shatov VM, Sluchanko NN, Gusev NB. Replacement of Arg in the conserved N-terminal RLFDQxFG motif affects physico-chemical properties and chaperone-like activity of human small heat shock protein HspB8 (Hsp22). PLoS One 2021; 16:e0253432. [PMID: 34143841 PMCID: PMC8213154 DOI: 10.1371/journal.pone.0253432] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Accepted: 06/04/2021] [Indexed: 01/06/2023] Open
Abstract
The small heat shock protein (sHsp) called HspB8 (formerly, Hsp22) is one of the least typical sHsp members, whose oligomerization status remains debatable. Here we analyze the effect of mutations in a highly conservative sequence located in the N-terminal domain of human HspB8 on its physico-chemical properties and chaperone-like activity. According to size-exclusion chromatography coupled to multi-angle light scattering, the wild type (WT) HspB8 is present as dominating monomeric species (~24 kDa) and a small fraction of oligomers (~60 kDa). The R29A amino acid substitution leads to the predominant formation of 60-kDa oligomers, leaving only a small fraction of monomers. Deletion of the 28–32 pentapeptide (Δ mutant) results in the formation of minor quantities of dimers (~49 kDa) and large quantities of the 24-kDa monomers. Both the WT protein and its Δ mutant efficiently bind a hydrophobic probe bis-ANS and are relatively rapidly hydrolyzed by chymotrypsin, whereas the R29A mutant weakly binds bis-ANS and resists chymotrypsinolysis. In contrast to HspB8 WT and its Δ mutant, which are well phosphorylated by cAMP-dependent and ERK1 protein kinases, the R29A mutant is poorly phosphorylated. R29A mutation affects the chaperone-like activity of HspB8 measured in vitro. It is concluded that the irreplaceable Arg residue located in the only highly conservative motif in the N-terminal domain of all sHsp proteins affects the oligomeric structure and key properties of HspB8.
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Affiliation(s)
- Vladislav M. Shatov
- Department of Biochemistry, School of Biology, Moscow State University, Moscow, Russian Federation
| | - Nikolai N. Sluchanko
- A.N. Bach Institute of Biochemistry, Federal Research Center of Biotechnology, Russian Academy of Sciences, Moscow, Russian Federation
| | - Nikolai B. Gusev
- Department of Biochemistry, School of Biology, Moscow State University, Moscow, Russian Federation
- * E-mail:
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11
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Structural basis of substrate recognition and thermal protection by a small heat shock protein. Nat Commun 2021; 12:3007. [PMID: 34021140 PMCID: PMC8140096 DOI: 10.1038/s41467-021-23338-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 04/23/2021] [Indexed: 12/12/2022] Open
Abstract
Small heat shock proteins (sHsps) bind unfolding proteins, thereby playing a pivotal role in the maintenance of proteostasis in virtually all living organisms. Structural elucidation of sHsp-substrate complexes has been hampered by the transient and heterogeneous nature of their interactions, and the precise mechanisms underlying substrate recognition, promiscuity, and chaperone activity of sHsps remain unclear. Here we show the formation of a stable complex between Arabidopsis thaliana plastid sHsp, Hsp21, and its natural substrate 1-deoxy-D-xylulose 5-phosphate synthase (DXPS) under heat stress, and report cryo-electron microscopy structures of Hsp21, DXPS and Hsp21-DXPS complex at near-atomic resolution. Monomeric Hsp21 binds across the dimer interface of DXPS and engages in multivalent interactions by recognizing highly dynamic structural elements in DXPS. Hsp21 partly unfolds its central α-crystallin domain to facilitate binding of DXPS, which preserves a native-like structure. This mode of interaction suggests a mechanism of sHsps anti-aggregation activity towards a broad range of substrates.
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12
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Kamenik AS, Handle PH, Hofer F, Kahler U, Kraml J, Liedl KR. Polarizable and non-polarizable force fields: Protein folding, unfolding, and misfolding. J Chem Phys 2021; 153:185102. [PMID: 33187403 DOI: 10.1063/5.0022135] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Molecular dynamics simulations are an invaluable tool to characterize the dynamic motions of proteins in atomistic detail. However, the accuracy of models derived from simulations inevitably relies on the quality of the underlying force field. Here, we present an evaluation of current non-polarizable and polarizable force fields (AMBER ff14SB, CHARMM 36m, GROMOS 54A7, and Drude 2013) based on the long-standing biophysical challenge of protein folding. We quantify the thermodynamics and kinetics of the β-hairpin formation using Markov state models of the fast-folding mini-protein CLN025. Furthermore, we study the (partial) folding dynamics of two more complex systems, a villin headpiece variant and a WW domain. Surprisingly, the polarizable force field in our set, Drude 2013, consistently leads to destabilization of the native state, regardless of the secondary structure element present. All non-polarizable force fields, on the other hand, stably characterize the native state ensembles in most cases even when starting from a partially unfolded conformation. Focusing on CLN025, we find that the conformational space captured with AMBER ff14SB and CHARMM 36m is comparable, but the ensembles from CHARMM 36m simulations are clearly shifted toward disordered conformations. While the AMBER ff14SB ensemble overstabilizes the native fold, CHARMM 36m and GROMOS 54A7 ensembles both agree remarkably well with experimental state populations. In addition, GROMOS 54A7 also reproduces experimental folding times most accurately. Our results further indicate an over-stabilization of helical structures with AMBER ff14SB. Nevertheless, the presented investigations strongly imply that reliable (un)folding dynamics of small proteins can be captured in feasible computational time with current additive force fields.
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Affiliation(s)
- Anna S Kamenik
- Institute of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Innrain 80/82, A-6020 Innsbruck, Austria
| | - Philip H Handle
- Institute of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Innrain 80/82, A-6020 Innsbruck, Austria
| | - Florian Hofer
- Institute of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Innrain 80/82, A-6020 Innsbruck, Austria
| | - Ursula Kahler
- Institute of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Innrain 80/82, A-6020 Innsbruck, Austria
| | - Johannes Kraml
- Institute of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Innrain 80/82, A-6020 Innsbruck, Austria
| | - Klaus R Liedl
- Institute of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Innrain 80/82, A-6020 Innsbruck, Austria
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Radzinski M, Oppenheim T, Metanis N, Reichmann D. The Cys Sense: Thiol Redox Switches Mediate Life Cycles of Cellular Proteins. Biomolecules 2021; 11:469. [PMID: 33809923 PMCID: PMC8004198 DOI: 10.3390/biom11030469] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Revised: 03/15/2021] [Accepted: 03/16/2021] [Indexed: 12/14/2022] Open
Abstract
Protein homeostasis is an essential component of proper cellular function; however, sustaining protein health is a challenging task, especially during the aerobic lifestyle. Natural cellular oxidants may be involved in cell signaling and antibacterial defense; however, imbalanced levels can lead to protein misfolding, cell damage, and death. This merges together the processes of protein homeostasis and redox regulation. At the heart of this process are redox-regulated proteins or thiol-based switches, which carefully mediate various steps of protein homeostasis across folding, localization, quality control, and degradation pathways. In this review, we discuss the "redox code" of the proteostasis network, which shapes protein health during cell growth and aging. We describe the sources and types of thiol modifications and elaborate on diverse strategies of evolving antioxidant proteins in proteostasis networks during oxidative stress conditions. We also highlight the involvement of cysteines in protein degradation across varying levels, showcasing the importance of cysteine thiols in proteostasis at large. The individual examples and mechanisms raised open the door for extensive future research exploring the interplay between the redox and protein homeostasis systems. Understanding this interplay will enable us to re-write the redox code of cells and use it for biotechnological and therapeutic purposes.
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Affiliation(s)
- Meytal Radzinski
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, Safra Campus Givat Ram, The Hebrew University of Jerusalem, Jerusalem 91904, Israel; (M.R.); (T.O.)
| | - Tal Oppenheim
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, Safra Campus Givat Ram, The Hebrew University of Jerusalem, Jerusalem 91904, Israel; (M.R.); (T.O.)
| | - Norman Metanis
- Institute of Chemistry, Safra Campus Givat Ram, The Hebrew University of Jerusalem, Jerusalem 91904, Israel;
| | - Dana Reichmann
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, Safra Campus Givat Ram, The Hebrew University of Jerusalem, Jerusalem 91904, Israel; (M.R.); (T.O.)
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14
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Makley LN, Johnson OT, Ghanakota P, Rauch JN, Osborn D, Wu TS, Cierpicki T, Carlson HA, Gestwicki JE. Chemical validation of a druggable site on Hsp27/HSPB1 using in silico solvent mapping and biophysical methods. Bioorg Med Chem 2021; 34:115990. [PMID: 33549906 PMCID: PMC7968374 DOI: 10.1016/j.bmc.2020.115990] [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] [Received: 11/14/2020] [Revised: 12/24/2020] [Accepted: 12/28/2020] [Indexed: 11/26/2022]
Abstract
Destabilizing mutations in small heat shock proteins (sHsps) are linked to multiple diseases; however, sHsps are conformationally dynamic, lack enzymatic function and have no endogenous chemical ligands. These factors render sHsps as classically "undruggable" targets and make it particularly challenging to identify molecules that might bind and stabilize them. To explore potential solutions, we designed a multi-pronged screening workflow involving a combination of computational and biophysical ligand-discovery platforms. Using the core domain of the sHsp family member Hsp27/HSPB1 (Hsp27c) as a target, we applied mixed solvent molecular dynamics (MixMD) to predict three possible binding sites, which we confirmed using NMR-based solvent mapping. Using this knowledge, we then used NMR spectroscopy to carry out a fragment-based drug discovery (FBDD) screen, ultimately identifying two fragments that bind to one of these sites. A medicinal chemistry effort improved the affinity of one fragment by ~50-fold (16 µM), while maintaining good ligand efficiency (~0.32 kcal/mol/non-hydrogen atom). Finally, we found that binding to this site partially restored the stability of disease-associated Hsp27 variants, in a redox-dependent manner. Together, these experiments suggest a new and unexpected binding site on Hsp27, which might be exploited to build chemical probes.
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Affiliation(s)
- Leah N Makley
- Department of Pharmaceutical Chemistry and the Institute for Neurodegenerative Disease, University of California at San Francisco, San Francisco, CA 94158, United States; Department of Medicinal Chemistry, University of Michigan, Ann Arbor, MI 48109, United States
| | - Oleta T Johnson
- Department of Pharmaceutical Chemistry and the Institute for Neurodegenerative Disease, University of California at San Francisco, San Francisco, CA 94158, United States
| | - Phani Ghanakota
- Department of Medicinal Chemistry, University of Michigan, Ann Arbor, MI 48109, United States
| | - Jennifer N Rauch
- Department of Pharmaceutical Chemistry and the Institute for Neurodegenerative Disease, University of California at San Francisco, San Francisco, CA 94158, United States
| | - Delaney Osborn
- Department of Pharmaceutical Chemistry and the Institute for Neurodegenerative Disease, University of California at San Francisco, San Francisco, CA 94158, United States
| | - Taia S Wu
- Department of Pharmaceutical Chemistry and the Institute for Neurodegenerative Disease, University of California at San Francisco, San Francisco, CA 94158, United States
| | - Tomasz Cierpicki
- Department of Pathology, University of Michigan, Ann Arbor, MI, 48109, United States
| | - Heather A Carlson
- Department of Medicinal Chemistry, University of Michigan, Ann Arbor, MI 48109, United States
| | - Jason E Gestwicki
- Department of Pharmaceutical Chemistry and the Institute for Neurodegenerative Disease, University of California at San Francisco, San Francisco, CA 94158, United States.
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15
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Alderson TR, Adriaenssens E, Asselbergh B, Pritišanac I, Van Lent J, Gastall HY, Wälti MA, Louis JM, Timmerman V, Baldwin AJ, Lp Benesch J. A weakened interface in the P182L variant of HSP27 associated with severe Charcot-Marie-Tooth neuropathy causes aberrant binding to interacting proteins. EMBO J 2021; 40:e103811. [PMID: 33644875 PMCID: PMC8047445 DOI: 10.15252/embj.2019103811] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 01/10/2021] [Accepted: 01/14/2021] [Indexed: 01/18/2023] Open
Abstract
HSP27 is a human molecular chaperone that forms large, dynamic oligomers and functions in many aspects of cellular homeostasis. Mutations in HSP27 cause Charcot‐Marie‐Tooth (CMT) disease, the most common inherited disorder of the peripheral nervous system. A particularly severe form of CMT disease is triggered by the P182L mutation in the highly conserved IxI/V motif of the disordered C‐terminal region, which interacts weakly with the structured core domain of HSP27. Here, we observed that the P182L mutation disrupts the chaperone activity and significantly increases the size of HSP27 oligomers formed in vivo, including in motor neurons differentiated from CMT patient‐derived stem cells. Using NMR spectroscopy, we determined that the P182L mutation decreases the affinity of the HSP27 IxI/V motif for its own core domain, leaving this binding site more accessible for other IxI/V‐containing proteins. We identified multiple IxI/V‐bearing proteins that bind with higher affinity to the P182L variant due to the increased availability of the IxI/V‐binding site. Our results provide a mechanistic basis for the impact of the P182L mutation on HSP27 and suggest that the IxI/V motif plays an important, regulatory role in modulating protein–protein interactions.
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Affiliation(s)
- T Reid Alderson
- Chemistry Research Laboratory, University of Oxford, Oxford, UK.,Laboratory of Chemical Physics, National Institutes of Health, Bethesda, MD, USA
| | - Elias Adriaenssens
- Peripheral Neuropathy Research Group, Department of Biomedical Sciences, Institute Born Bunge, University of Antwerp, Antwerpen, Belgium
| | - Bob Asselbergh
- Neuromics Support Facility, VIB Center for Molecular Neurology, VIB, Antwerpen, Belgium.,Neuromics Support Facility, Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium
| | - Iva Pritišanac
- Molecular Medicine Program, The Hospital for Sick Children, Toronto, ON, Canada
| | - Jonas Van Lent
- Peripheral Neuropathy Research Group, Department of Biomedical Sciences, Institute Born Bunge, University of Antwerp, Antwerpen, Belgium
| | - Heidi Y Gastall
- Chemistry Research Laboratory, University of Oxford, Oxford, UK
| | - Marielle A Wälti
- Laboratory of Chemical Physics, National Institutes of Health, Bethesda, MD, USA
| | - John M Louis
- Laboratory of Chemical Physics, National Institutes of Health, Bethesda, MD, USA
| | - Vincent Timmerman
- Peripheral Neuropathy Research Group, Department of Biomedical Sciences, Institute Born Bunge, University of Antwerp, Antwerpen, Belgium
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16
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Siegel A, McAvoy CZ, Lam V, Liang FC, Kroon G, Miaou E, Griffin P, Wright PE, Shan SO. A Disorder-to-Order Transition Activates an ATP-Independent Membrane Protein Chaperone. J Mol Biol 2020; 432:166708. [PMID: 33188783 PMCID: PMC7780713 DOI: 10.1016/j.jmb.2020.11.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 11/05/2020] [Accepted: 11/06/2020] [Indexed: 01/20/2023]
Abstract
The 43 kDa subunit of the chloroplast signal recognition particle, cpSRP43, is an ATP-independent chaperone essential for the biogenesis of the light harvesting chlorophyll-binding proteins (LHCP), the most abundant membrane protein family on earth. cpSRP43 is activated by a stromal factor, cpSRP54, to more effectively capture and solubilize LHCPs. The molecular mechanism underlying this chaperone activation is unclear. Here, a combination of hydrogen-deuterium exchange, electron paramagnetic resonance, and NMR spectroscopy experiments reveal that a disorder-to-order transition of the ankyrin repeat motifs in the substrate binding domain of cpSRP43 drives its activation. An analogous coil-to-helix transition in the bridging helix, which connects the ankyrin repeat motifs to the cpSRP54 binding site in the second chromodomain, mediates long-range allosteric communication of cpSRP43 with its activating binding partner. Our results provide a molecular model to explain how the conformational dynamics of cpSRP43 enables regulation of its chaperone activity and suggest a general mechanism by which ATP-independent chaperones with cooperatively folding domains can be regulated.
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Affiliation(s)
- Alex Siegel
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, United States
| | - Camille Z McAvoy
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, United States
| | - Vinh Lam
- Department of Molecular Medicine, Florida Campus, The Scripps Research Institute, Jupiter, FL 33458, United States
| | - Fu-Cheng Liang
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, United States
| | - Gerard Kroon
- Department of Integrative Structural and Computational Biology and the Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037, United States
| | - Emily Miaou
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, United States
| | - Patrick Griffin
- Department of Molecular Medicine, Florida Campus, The Scripps Research Institute, Jupiter, FL 33458, United States
| | - Peter E Wright
- Department of Integrative Structural and Computational Biology and the Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037, United States
| | - Shu-Ou Shan
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, United States.
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17
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Chaplot K, Jarvela TS, Lindberg I. Secreted Chaperones in Neurodegeneration. Front Aging Neurosci 2020; 12:268. [PMID: 33192447 PMCID: PMC7481362 DOI: 10.3389/fnagi.2020.00268] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 08/03/2020] [Indexed: 12/11/2022] Open
Abstract
Protein homeostasis, or proteostasis, is a combination of cellular processes that govern protein quality control, namely, protein translation, folding, processing, and degradation. Disruptions in these processes can lead to protein misfolding and aggregation. Proteostatic disruption can lead to cellular changes such as endoplasmic reticulum or oxidative stress; organelle dysfunction; and, if continued, to cell death. A majority of neurodegenerative diseases involve the pathologic aggregation of proteins that subverts normal neuronal function. While prior reviews of neuronal proteostasis in neurodegenerative processes have focused on cytoplasmic chaperones, there is increasing evidence that chaperones secreted both by neurons and other brain cells in the extracellular – including transsynaptic – space play important roles in neuronal proteostasis. In this review, we will introduce various secreted chaperones involved in neurodegeneration. We begin with clusterin and discuss its identification in various protein aggregates, and the use of increased cerebrospinal fluid (CSF) clusterin as a potential biomarker and as a potential therapeutic. Our next secreted chaperone is progranulin; polymorphisms in this gene represent a known genetic risk factor for frontotemporal lobar degeneration, and progranulin overexpression has been found to be effective in reducing Alzheimer’s- and Parkinson’s-like neurodegenerative phenotypes in mouse models. We move on to BRICHOS domain-containing proteins, a family of proteins containing highly potent anti-amyloidogenic activity; we summarize studies describing the biochemical mechanisms by which recombinant BRICHOS protein might serve as a therapeutic agent. The next section of the review is devoted to the secreted chaperones 7B2 and proSAAS, small neuronal proteins which are packaged together with neuropeptides and released during synaptic activity. Since proteins can be secreted by both classical secretory and non-classical mechanisms, we also review the small heat shock proteins (sHsps) that can be secreted from the cytoplasm to the extracellular environment and provide evidence for their involvement in extracellular proteostasis and neuroprotection. Our goal in this review focusing on extracellular chaperones in neurodegenerative disease is to summarize the most recent literature relating to neurodegeneration for each secreted chaperone; to identify any common mechanisms; and to point out areas of similarity as well as differences between the secreted chaperones identified to date.
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Affiliation(s)
- Kriti Chaplot
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, University of Maryland, Baltimore, Baltimore, MD, United States
| | - Timothy S Jarvela
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, University of Maryland, Baltimore, Baltimore, MD, United States
| | - Iris Lindberg
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, University of Maryland, Baltimore, Baltimore, MD, United States
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18
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Proteinaceous Transformers: Structural and Functional Variability of Human sHsps. Int J Mol Sci 2020; 21:ijms21155448. [PMID: 32751672 PMCID: PMC7432308 DOI: 10.3390/ijms21155448] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 07/27/2020] [Accepted: 07/29/2020] [Indexed: 02/04/2023] Open
Abstract
The proteostasis network allows organisms to support and regulate the life cycle of proteins. Especially regarding stress, molecular chaperones represent the main players within this network. Small heat shock proteins (sHsps) are a diverse family of ATP-independent molecular chaperones acting as the first line of defense in many stress situations. Thereby, the promiscuous interaction of sHsps with substrate proteins results in complexes from which the substrates can be refolded by ATP-dependent chaperones. Particularly in vertebrates, sHsps are linked to a broad variety of diseases and are needed to maintain the refractive index of the eye lens. A striking key characteristic of sHsps is their existence in ensembles of oligomers with varying numbers of subunits. The respective dynamics of these molecules allow the exchange of subunits and the formation of hetero-oligomers. Additionally, these dynamics are closely linked to the chaperone activity of sHsps. In current models a shift in the equilibrium of the sHsp ensemble allows regulation of the chaperone activity, whereby smaller oligomers are commonly the more active species. Different triggers reversibly change the oligomer equilibrium and regulate the activity of sHsps. However, a finite availability of high-resolution structures of sHsps still limits a detailed mechanistic understanding of their dynamics and the correlating recognition of substrate proteins. Here we summarize recent advances in understanding the structural and functional relationships of human sHsps with a focus on the eye-lens αA- and αB-crystallins.
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19
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Affiliation(s)
- Sichun Yang
- Center for Proteomics and Department of Nutrition, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA.
| | - Pau Bernadó
- Centre de Biochimie Structurale (CBS), INSERM, CNRS, Université de Montpellier, 29, rue de Navacelles, 34090 Montpellier, France.
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