1
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Silva NSM, Siebeneichler B, Oliveira CS, Dores-Silva PR, Borges JC. The regulation of the thermal stability and affinity of the HSPA5 (Grp78/BiP) by clients and nucleotides is modulated by domains coupling. BIOCHIMICA ET BIOPHYSICA ACTA. PROTEINS AND PROTEOMICS 2024:141034. [PMID: 39009203 DOI: 10.1016/j.bbapap.2024.141034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2024] [Revised: 07/03/2024] [Accepted: 07/09/2024] [Indexed: 07/17/2024]
Abstract
The HSPA5 protein (BiP/Grp78) serves as a pivotal chaperone in maintaining cellular protein quality control. As a member of the human HSP70 family, HSPA5 comprises two distinct domains: a nucleotide-binding domain (NBD) and a peptide-binding domain (PBD). In this study, we investigated the interdomain interactions of HSPA5, aiming to elucidate how these domains regulate its function as a chaperone. Our findings revealed that HSPA5-FL, HSPA5-T, and HSPA5-N exhibit varying affinities for ATP and ADP, with a noticeable dependency on Mg2+ for optimal interactions. Interestingly, in ADP assays, the presence of the metal ion seems to enhance NBD binding only for HSPA5-FL and HSPA5-T. Moreover, while the truncation of the C-terminus does not significantly impact the thermal stability of HSPA5, experiments involving MgATP underscore its essential role in mediating interactions and nucleotide hydrolysis. Thermal stability assays further suggested that the NBD-PBD interface enhances the stability of the NBD, more pronounced for HSPA5 than for the orthologous HSPA1A, and prevents self-aggregation through interdomain coupling. Enzymatic analyses indicated that the presence of PBD enhances NBD ATPase activity and augments its nucleotide affinity. Notably, the intrinsic chaperone activity of the PBD is dependent on the presence of the NBD, potentially due to the propensity of the PBD for self-oligomerization. Collectively, our data highlight the pivotal role of allosteric mechanisms in modulating thermal stability, nucleotide interaction, and ATPase activity of HSPA5, underscoring its significance in protein quality control within cellular environments.
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Affiliation(s)
- Noeli S M Silva
- São Carlos Institute of Chemistry, University of São Paulo, São Carlos, SP, Brazil.
| | - Bruna Siebeneichler
- São Carlos Institute of Chemistry, University of São Paulo, São Carlos, SP, Brazil; Exact and Technology Sciences Center, Federal University of São Carlos, São Carlos, SP 13560-970, Brazil
| | - Carlos S Oliveira
- São Carlos Institute of Chemistry, University of São Paulo, São Carlos, SP, Brazil
| | - Paulo R Dores-Silva
- São Carlos Institute of Chemistry, University of São Paulo, São Carlos, SP, Brazil
| | - Júlio C Borges
- São Carlos Institute of Chemistry, University of São Paulo, São Carlos, SP, Brazil.
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2
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Reed AL, Mitchell W, Alexandrescu AT, Alder NN. Interactions of amyloidogenic proteins with mitochondrial protein import machinery in aging-related neurodegenerative diseases. Front Physiol 2023; 14:1263420. [PMID: 38028797 PMCID: PMC10652799 DOI: 10.3389/fphys.2023.1263420] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 10/02/2023] [Indexed: 12/01/2023] Open
Abstract
Most mitochondrial proteins are targeted to the organelle by N-terminal mitochondrial targeting sequences (MTSs, or "presequences") that are recognized by the import machinery and subsequently cleaved to yield the mature protein. MTSs do not have conserved amino acid compositions, but share common physicochemical properties, including the ability to form amphipathic α-helical structures enriched with basic and hydrophobic residues on alternating faces. The lack of strict sequence conservation implies that some polypeptides can be mistargeted to mitochondria, especially under cellular stress. The pathogenic accumulation of proteins within mitochondria is implicated in many aging-related neurodegenerative diseases, including Alzheimer's, Parkinson's, and Huntington's diseases. Mechanistically, these diseases may originate in part from mitochondrial interactions with amyloid-β precursor protein (APP) or its cleavage product amyloid-β (Aβ), α-synuclein (α-syn), and mutant forms of huntingtin (mHtt), respectively, that are mediated in part through their associations with the mitochondrial protein import machinery. Emerging evidence suggests that these amyloidogenic proteins may present cryptic targeting signals that act as MTS mimetics and can be recognized by mitochondrial import receptors and transported into different mitochondrial compartments. Accumulation of these mistargeted proteins could overwhelm the import machinery and its associated quality control mechanisms, thereby contributing to neurological disease progression. Alternatively, the uptake of amyloidogenic proteins into mitochondria may be part of a protein quality control mechanism for clearance of cytotoxic proteins. Here we review the pathomechanisms of these diseases as they relate to mitochondrial protein import and effects on mitochondrial function, what features of APP/Aβ, α-syn and mHtt make them suitable substrates for the import machinery, and how this information can be leveraged for the development of therapeutic interventions.
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Affiliation(s)
- Ashley L. Reed
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, United States
| | - Wayne Mitchell
- Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, United States
| | - Andrei T. Alexandrescu
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, United States
| | - Nathan N. Alder
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, United States
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3
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Moritz MNO, Dores-Silva PR, Coto ALS, Selistre-de-Araújo HS, Leitão A, Cauvi DM, De Maio A, Carra S, Borges JC. Human HSP70-escort protein 1 (hHep1) interacts with negatively charged lipid bilayers and cell membranes. Cell Stress Chaperones 2023; 28:1001-1012. [PMID: 38001371 PMCID: PMC10746634 DOI: 10.1007/s12192-023-01394-1] [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: 07/17/2023] [Revised: 11/09/2023] [Accepted: 11/10/2023] [Indexed: 11/26/2023] Open
Abstract
Human Hsp70-escort protein 1 (hHep1) is a cochaperone that assists in the function and stability of mitochondrial HSPA9. Similar to HSPA9, hHep1 is located outside the mitochondria and can interact with liposomes. In this study, we further investigated the structural and thermodynamic behavior of interactions between hHep1 and negatively charged liposomes, as well as interactions with cellular membranes. Our results showed that hHep1 interacts peripherally with liposomes formed by phosphatidylserine and cardiolipin and remains partially structured, exhibiting similar affinities for both. In addition, after being added to the cell membrane, recombinant hHep1 was incorporated by cells in a dose-dependent manner. Interestingly, the association of HSPA9 with hHep1 improved the incorporation of these proteins into the lipid bilayer. These results demonstrated that hHep1 can interact with lipids also present in the plasma membrane, indicating roles for this cochaperone outside of mitochondria.
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Affiliation(s)
- Milene N O Moritz
- São Carlos Institute of Chemistry, University of São Paulo - USP, P.O. Box 780, São Carlos, SP, 13560-970, Brazil
| | - Paulo R Dores-Silva
- São Carlos Institute of Chemistry, University of São Paulo - USP, P.O. Box 780, São Carlos, SP, 13560-970, Brazil
- Division of Trauma, Critical Care, Burns and Acute Care Surgery, Department of Surgery, School of Medicine, University of California San Diego, La Jolla, CA, 92093, USA
| | - Amanda L S Coto
- São Carlos Institute of Chemistry, University of São Paulo - USP, P.O. Box 780, São Carlos, SP, 13560-970, Brazil
| | | | - Andrei Leitão
- São Carlos Institute of Chemistry, University of São Paulo - USP, P.O. Box 780, São Carlos, SP, 13560-970, Brazil
| | - David M Cauvi
- Division of Trauma, Critical Care, Burns and Acute Care Surgery, Department of Surgery, School of Medicine, University of California San Diego, La Jolla, CA, 92093, USA
| | - Antonio De Maio
- Division of Trauma, Critical Care, Burns and Acute Care Surgery, Department of Surgery, School of Medicine, University of California San Diego, La Jolla, CA, 92093, USA
| | - Serena Carra
- Centre for Neuroscience and Nanotechnology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Júlio Cesar Borges
- São Carlos Institute of Chemistry, University of São Paulo - USP, P.O. Box 780, São Carlos, SP, 13560-970, Brazil.
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4
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Abstract
Zinc is an essential element for human health. Among its many functions, zinc(II) modulates the immune response to infections and, at high concentrations or in the presence of ionophores, inhibits the replication of various RNA viruses. Structural biology studies on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) revealed that zinc(II) is the most common metal ion that binds to viral proteins. However, the number of zinc(II)-binding sites identified by experimental methods is far from exhaustive, as metal ions may be lost during protein purification protocols. To better define the zinc(II)-binding proteome of coronavirus, we leveraged the wealth of deposited structural data and state-of-the-art bioinformatics methods. Through this in silico approach, 15 experimental zinc(II) sites were identified and a further 22 were predicted in Spike, open reading frame (ORF)3a/d, ORF8, and several nonstructural proteins, highlighting an essential role of zinc(II) in viral replication. Furthermore, the structural relationships between viral and eukaryotic sites (typically zinc fingers) indicate that SARS-CoV-2 can compete with human proteins for zinc(II) binding. Given the double-edged effect of zinc(II) ions, both essential and toxic to coronavirus, only the complete elucidation of the structural and regulatory zinc(II)-binding sites can guide selective antiviral strategies based on zinc supplementation.
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Affiliation(s)
- Claudia Andreini
- Consorzio Interuniversitario di Risonanze Magnetiche di Metallo Proteine, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Italy
- Department of Chemistry and Magnetic Resonance Center (CERM), University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Italy
| | - Fabio Arnesano
- Department of Chemistry, University of Bari “Aldo Moro,” Via Orabona 4, 70125 Bari, Italy
| | - Antonio Rosato
- Consorzio Interuniversitario di Risonanze Magnetiche di Metallo Proteine, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Italy
- Department of Chemistry and Magnetic Resonance Center (CERM), University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Italy
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5
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Bahr T, Katuri J, Liang T, Bai Y. Mitochondrial chaperones in human health and disease. Free Radic Biol Med 2022; 179:363-374. [PMID: 34780988 PMCID: PMC8893670 DOI: 10.1016/j.freeradbiomed.2021.11.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 10/29/2021] [Accepted: 11/10/2021] [Indexed: 02/03/2023]
Abstract
Molecular chaperones are a family of proteins that maintain cellular protein homeostasis through non-covalent peptide folding and quality control mechanisms. The chaperone proteins found within mitochondria play significant protective roles in mitochondrial biogenesis, quality control, and stress response mechanisms. Defective mitochondrial chaperones have been implicated in aging, neurodegeneration, and cancer. In this review, we focus on the two most prominent mitochondrial chaperones: mtHsp60 and mtHsp70. These proteins demonstrate different cellular localization patterns, interact with different targets, and have different functional activities. We discuss the structure and function of these prominent mitochondrial chaperone proteins and give an update on newly discovered regulatory mechanisms and disease implications.
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Affiliation(s)
- Tyler Bahr
- Department of Cell Systems & Anatomy University of Texas Health San Antonio, 7703 Floyd Curl Dr, San Antonio, TX, 78229, USA
| | - Joshua Katuri
- Department of Cell Systems & Anatomy University of Texas Health San Antonio, 7703 Floyd Curl Dr, San Antonio, TX, 78229, USA
| | - Ting Liang
- Department of Cell Systems & Anatomy University of Texas Health San Antonio, 7703 Floyd Curl Dr, San Antonio, TX, 78229, USA
| | - Yidong Bai
- Department of Cell Systems & Anatomy University of Texas Health San Antonio, 7703 Floyd Curl Dr, San Antonio, TX, 78229, USA.
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6
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Silva NSM, Rodrigues LFDC, Dores-Silva PR, Montanari CA, Ramos CHI, Barbosa LRS, Borges JC. Structural, thermodynamic and functional studies of human 71 kDa heat shock cognate protein (HSPA8/hHsc70). BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2021; 1869:140719. [PMID: 34571256 DOI: 10.1016/j.bbapap.2021.140719] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Revised: 08/29/2021] [Accepted: 09/21/2021] [Indexed: 01/14/2023]
Abstract
Human 71 kDa heat shock cognate protein (HSPA8, also known as Hsc70, Hsp70-8, Hsc71, Hsp71 or Hsp73) is a constitutively expressed chaperone that is critical for cell proteostasis. In the cytosol, HSPA8 plays a pivotal role in folding and refolding, facilitates protein trafficking across membranes and targets proteins for degradation, among other functions. Here, we report an in solution study of recombinant HSPA8 (rHSPA8) using a variety of biophysical and biochemical approaches. rHSPA8 shares several structural and functional similarities with others human Hsp70s. It has two domains with different stabilities and interacts with adenosine nucleotides with dissociation constants in the low micromolar range, which were higher in the presence of Mg2+. rHSPA8 showed lower ATPase activity than its homolog HSPA5/hGrp78/hBiP, but it was 4-fold greater than that of recombinant HSPA1A/hHsp70-1A, with which it is 86% identical. Small angle X-ray scattering indicated that rHSPA8 behaved as an elongated monomeric protein in solution with dimensions similar to those observed for HSPA1A. In addition, rHSPA8 showed structural flexibility between its compacted and extended conformations. The data also indicated that HSPA8 has capacity in preventing the aggregation of model client proteins. The present study expands the understanding of the structure and activity of this chaperone and aligns with the idea that human homologous Hsp70s have divergent functions.
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Affiliation(s)
| | | | - Paulo Roberto Dores-Silva
- São Carlos Institute of Chemistry, University of São Paulo, São Carlos, SP, Brazil; Division of Trauma, Critical Care, Burns and Acute Care Surgery, Department of Surgery School of Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | | | | | - Leandro Ramos Souza Barbosa
- Institute of Physics, University of São Paulo, São Paulo, SP, Brazil; Brazilian Synchrotron Light Laboratory (LNLS), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, Brazil
| | - Júlio César Borges
- São Carlos Institute of Chemistry, University of São Paulo, São Carlos, SP, Brazil.
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7
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Mitochondrial HSP70 Chaperone System-The Influence of Post-Translational Modifications and Involvement in Human Diseases. Int J Mol Sci 2021; 22:ijms22158077. [PMID: 34360841 PMCID: PMC8347752 DOI: 10.3390/ijms22158077] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 07/23/2021] [Accepted: 07/26/2021] [Indexed: 01/25/2023] Open
Abstract
Since their discovery, heat shock proteins (HSPs) have been identified in all domains of life, which demonstrates their importance and conserved functional role in maintaining protein homeostasis. Mitochondria possess several members of the major HSP sub-families that perform essential tasks for keeping the organelle in a fully functional and healthy state. In humans, the mitochondrial HSP70 chaperone system comprises a central molecular chaperone, mtHSP70 or mortalin (HSPA9), which is actively involved in stabilizing and importing nuclear gene products and in refolding mitochondrial precursor proteins, and three co-chaperones (HSP70-escort protein 1-HEP1, tumorous imaginal disc protein 1-TID-1, and Gro-P like protein E-GRPE), which regulate and accelerate its protein folding functions. In this review, we summarize the roles of mitochondrial molecular chaperones with particular focus on the human mtHsp70 and its co-chaperones, whose deregulated expression, mutations, and post-translational modifications are often considered to be the main cause of neurological disorders, genetic diseases, and malignant growth.
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8
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Dores-Silva PR, Kiraly VTR, Moritz MNDO, Serrão VHB, Dos Passos PMS, Spagnol V, Teixeira FR, Gava LM, Cauvi DM, Ramos CHI, De Maio A, Borges JC. New insights on human Hsp70-escort protein 1: Chaperone activity, interaction with liposomes, cellular localizations and HSPA's self-assemblies remodeling. Int J Biol Macromol 2021; 182:772-784. [PMID: 33857516 DOI: 10.1016/j.ijbiomac.2021.04.048] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 04/09/2021] [Accepted: 04/09/2021] [Indexed: 11/24/2022]
Abstract
The 70 kDa heat shock proteins (Hsp70) are prone to self-assembly under thermal stress conditions, forming supramolecular assemblies (SMA), what may have detrimental consequences for cellular viability. In mitochondria, the cochaperone Hsp70-escort protein 1 (Hep1) maintains mitochondrial Hsp70 (mtHsp70) in a soluble and functional state, contributing to preserving proteostasis. Here we investigated the interaction between human Hep1 (hHep1) and HSPA9 (human mtHsp70) or HSPA1A (Hsp70-1A) in monomeric and thermic SMA states to unveil further information about the involved mechanisms. hHep1 was capable of blocking the formation of HSPA SMAs under a thermic treatment and stimulated HSPA ATPase activity in both monomeric and preformed SMA. The interaction of hHep1 with both monomeric and SMA HSPAs displayed a stoichiometric ratio close to 1, suggesting that hHep1 has access to most protomers within the SMA. Interestingly, hHep1 remodeled HSPA9 and HSPA1A SMAs into smaller forms. Furthermore, hHep1 was detected in the mitochondria and nucleus of cells transfected with the respective coding DNA and interacted with liposomes resembling mitochondrial membranes. Altogether, these new features reinforce that hHep1 act as a "chaperone for a chaperone", which may play a critical role in cellular proteostasis.
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Affiliation(s)
- Paulo Roberto Dores-Silva
- Sao Carlos Institute of Chemistry, University of Sao Paulo, Sao Carlos, SP, Brazil; Department of Surgery, School of Medicine, University of California, San Diego, La Jolla, USA
| | | | | | | | | | - Valentine Spagnol
- Department of Genetics and Evolution, Federal University of Sao Carlos, SP, Brazil
| | | | | | - David Mario Cauvi
- Department of Surgery, School of Medicine, University of California, San Diego, La Jolla, USA
| | | | - Antonio De Maio
- Department of Surgery, School of Medicine, University of California, San Diego, La Jolla, USA; Center for Investigations of Health and Education Disparities, University of California, San Diego, La Jolla, USA; Department of Neurosciences, School of Medicine, University of California, San Diego, La Jolla, USA
| | - Júlio César Borges
- Sao Carlos Institute of Chemistry, University of Sao Paulo, Sao Carlos, SP, Brazil.
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9
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Dores-Silva PR, Cauvi DM, Kiraly VTR, Borges JC, De Maio A. Human HSPA9 (mtHsp70, mortalin) interacts with lipid bilayers containing cardiolipin, a major component of the inner mitochondrial membrane. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183436. [PMID: 32781155 DOI: 10.1016/j.bbamem.2020.183436] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 07/21/2020] [Accepted: 07/22/2020] [Indexed: 12/16/2022]
Abstract
Mitochondrial Hsp70 (HSPA9, mtHsp70, mortalin) in conjunction with a complex set of other proteins is involved in the transport of polypeptides across the mitochondrial matrix. This observation allows us to hypothesize that HSPA9 might interact with membranes directly, similarly to other Hsp70s. Thus, we investigated whether human HSPA9 could also get inserted into lipid membranes. Human HSPA9 was incubated with liposomes made of lipids found within the mitochondrial membrane, such as 1', 3'-bis [1, 2-dimyristoyl-sn-glycero-3-phospho]-glycerol (CL), palmitoyl-oleoyl phosphocholine (POPC), palmitoyl-oleoyl phosphoserine (POPS), and palmitoyl-oleoyl phosphoethanolamine (POPE). HSPA9 displayed a predilection for CL and POPS, and low affinity for POPC and POPE, suggesting that the proteins have high specificity for negatively charged phospholipids. Then, liposomes were made with a composition resembling either the outer or inner mitochondrial membrane (OMM or IMM, respectively). We observed that HSPA9 has a higher affinity for IMM than OMM, which is consistent with the higher content of CL in the IMM. A comparison for the incorporation into POPS or CL liposomes by HSPA9 or HSPA1 indicated that both proteins behaved very similarly when exposed to CL liposomes, but differently with POPS liposomes, which was further corroborated by their susceptibility to proteinase K digestion after incorporation into liposomes. The measurement of thermodynamic parameters also showed that the interaction of both proteins with CL and POPS liposomes was different. Overall, our data showed that HSPA9 is prone to interact with membranes resembling the IMM that may be important for its role in the translocation of proteins into the mitochondria.
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Affiliation(s)
- Paulo Roberto Dores-Silva
- Division of Trauma, Critical Care, Burns and Acute Care Surgery, Department of Surgery, School of Medicine, University of California San Diego, La Jolla, CA 92093, USA; São Carlos Institute of Chemistry, University of São Paulo, São Paulo, Brazil
| | - David M Cauvi
- Division of Trauma, Critical Care, Burns and Acute Care Surgery, Department of Surgery, School of Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Vanessa T R Kiraly
- São Carlos Institute of Chemistry, University of São Paulo, São Paulo, Brazil
| | - Júlio C Borges
- São Carlos Institute of Chemistry, University of São Paulo, São Paulo, Brazil
| | - Antonio De Maio
- Division of Trauma, Critical Care, Burns and Acute Care Surgery, Department of Surgery, School of Medicine, University of California San Diego, La Jolla, CA 92093, USA; Division of Trauma, Critical Care, Burns and Acute Care Surgery, Department of Neurosciences, School of Medicine, University of California San Diego, La Jolla, CA 92093, USA.
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10
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Kiraly VTR, Dores-Silva PR, Serrão VHB, Cauvi DM, De Maio A, Borges JC. Thermal aggregates of human mortalin and Hsp70-1A behave as supramolecular assemblies. Int J Biol Macromol 2020; 146:320-331. [PMID: 31899237 PMCID: PMC7024674 DOI: 10.1016/j.ijbiomac.2019.12.236] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 12/24/2019] [Accepted: 12/25/2019] [Indexed: 12/12/2022]
Abstract
The Hsp70 family of heat shock proteins plays a critical function in maintaining cellular homeostasis within various subcellular compartments. The human mitochondrial Hsp70 (HSPA9) has been associated with cellular death, senescence, cancer and neurodegenerative diseases, which is the rational for the name mortalin. It is well documented that mortalin, such as other Hsp70s, is prone to self-aggregation, which is related to mitochondria biogenesis failure. Here, we investigated the assembly, structure and function of thermic aggregates/oligomers of recombinant human mortalin and Hsp70-1A (HSPA1A). Summarily, both Hsp70 thermic aggregates have characteristics of supramolecular assemblies. They display characteristic organized structures and partial ATPase activity, despite their nanometric size. Indeed, we observed that the interaction of these aggregates/oligomers with liposomes is similar to monomeric Hsp70s and, finally, they were non-toxic over neuroblastoma cells. These findings revealed that high molecular mass oligomers of mortalin and Hsp70-1A preserved some of the fundamental functions of these proteins.
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Affiliation(s)
- Vanessa T R Kiraly
- São Carlos Institute of Chemistry, University of São Paulo, São Carlos, SP, Brazil
| | - Paulo R Dores-Silva
- São Carlos Institute of Chemistry, University of São Paulo, São Carlos, SP, Brazil; Department of Surgery, School of Medicine University of California, La Jolla, USA
| | - Vitor H B Serrão
- Department Laboratory of Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
| | - David M Cauvi
- Department of Surgery, School of Medicine University of California, La Jolla, USA
| | - Antonio De Maio
- Department of Surgery, School of Medicine University of California, La Jolla, USA; Center for Investigations of Health and Education Disparities, University of California, San Diego, La Jolla, USA; Department of Neurosciences, School of Medicine, University of California, La Jolla, USA
| | - Júlio C Borges
- São Carlos Institute of Chemistry, University of São Paulo, São Carlos, SP, Brazil.
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11
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Srivastava S, Vishwanathan V, Birje A, Sinha D, D'Silva P. Evolving paradigms on the interplay of mitochondrial Hsp70 chaperone system in cell survival and senescence. Crit Rev Biochem Mol Biol 2020; 54:517-536. [PMID: 31997665 DOI: 10.1080/10409238.2020.1718062] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The role of mitochondria within a cell has grown beyond being the prime source of cellular energy to one of the major signaling platforms. Recent evidence provides several insights into the crucial roles of mitochondrial chaperones in regulating the organellar response to external triggers. The mitochondrial Hsp70 (mtHsp70/Mortalin/Grp75) chaperone system plays a critical role in the maintenance of proteostasis balance in the organelle. Defects in mtHsp70 network result in attenuated protein transport and misfolding of polypeptides leading to mitochondrial dysfunction. The functions of Hsp70 are primarily governed by J-protein cochaperones. Although human mitochondria possess a single Hsp70, its multifunctionality is characterized by the presence of multiple specific J-proteins. Several studies have shown a potential association of Hsp70 and J-proteins with diverse pathological states that are not limited to their canonical role as chaperones. The role of mitochondrial Hsp70 and its co-chaperones in disease pathogenesis has not been critically reviewed in recent years. We evaluated some of the cellular interfaces where Hsp70 machinery associated with pathophysiological conditions, particularly in context of tumorigenesis and neurodegeneration. The mitochondrial Hsp70 machinery shows a variable localization and integrates multiple components of the cellular processes with varied phenotypic consequences. Although Hsp70 and J-proteins function synergistically in proteins folding, their precise involvement in pathological conditions is mainly idiosyncratic. This machinery is associated with a heterogeneous set of molecules during the progression of a disorder. However, the precise binding to the substrate for a specific physiological response under a disease subtype is still an undocumented area of analysis.
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Affiliation(s)
- Shubhi Srivastava
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | | | - Abhijit Birje
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Devanjan Sinha
- Department of Zoology, Institute of Science, Banaras Hindu University, Varanasi, India
| | - Patrick D'Silva
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
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12
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Immunization with recombinant enolase of Sporothrix spp. (rSsEno) confers effective protection against sporotrichosis in mice. Sci Rep 2019; 9:17179. [PMID: 31748544 PMCID: PMC6868355 DOI: 10.1038/s41598-019-53135-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 10/26/2019] [Indexed: 01/19/2023] Open
Abstract
In recent years, research has focused on the immunoreactive components of the Sporothrix schenckii cell wall that can be relevant targets for preventive and therapeutic vaccines against sporotrichosis, an emergent worldwide mycosis. In a previous study, we identified a 47-kDa enolase as an immunodominant antigen in mice vaccinated with an adjuvanted mixture of S. schenckii cell wall proteins. Here, we sought to assess the protective potential of a Sporothrix spp. recombinant enolase (rSsEno) formulated with or without the adjuvant Montanide Pet-GelA (PGA) against the S. brasiliensis infection in mice. Mice that were immunized with rSsEno plus PGA showed increased antibody titters against rSsEno and increased median survival time when challenged with S. brasiliensis as compared with mice that had not been immunized or that were immunized with rSsEno alone. Immunization with rSsEno plus PGA induced a predominantly T-helper 1 cytokine pattern after in vitro stimulation of splenic cells with rSsEno: elevated levels of IFN-γ and IL-2, as well as of other cytokines involved in host defense against sporotrichosis, such as TNF-alpha, IL-6, and IL-4. Furthermore, we show for the first time the presence of enolase in the cell wall of both S. schenckii and S. brasiliensis. As a whole, our results suggest that enolase could be used as a potential antigenic target for vaccinal purposes against sporotrichosis.
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Alfadhel M, Nashabat M, Abu Ali Q, Hundallah K. Mitochondrial iron-sulfur cluster biogenesis from molecular understanding to clinical disease. ACTA ACUST UNITED AC 2019; 22:4-13. [PMID: 28064324 PMCID: PMC5726836 DOI: 10.17712/nsj.2017.1.20160542] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
Iron–sulfur clusters (ISCs) are known to play a major role in various protein functions. Located in the mitochondria, cytosol, endoplasmic reticulum and nucleus, they contribute to various core cellular functions. Until recently, only a few human diseases related to mitochondrial ISC biogenesis defects have been described. Such diseases include Friedreich ataxia, combined oxidative phosphorylation deficiency 19, infantile complex II/III deficiency defect, hereditary myopathy with lactic acidosis and mitochondrial muscle myopathy, lipoic acid biosynthesis defects, multiple mitochondrial dysfunctions syndromes and non ketotic hyperglycinemia due to glutaredoxin 5 gene defect. Disorders of mitochondrial import, export and translation, including sideroblastic anemia with ataxia, EVEN-PLUS syndrome and mitochondrial complex I deficiency due to nucleotide-binding protein-like protein gene defect, have also been implicated in ISC biogenesis defects. With advances in next generation sequencing technologies, more disorders related to ISC biogenesis defects are expected to be elucidated. In this article, we aim to shed the light on mitochondrial ISC biogenesis, related proteins and their function, pathophysiology, clinical phenotypes of related disorders, diagnostic approach, and future implications.
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Affiliation(s)
- Majid Alfadhel
- Division of Genetics, Department of Pediatrics, King Saud bin Abdulaziz University for Health Sciences, King Abdulaziz Medical City, Riyadh, Kingdom of Saudi Arabia
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14
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Quantitative proteomics analysis provides insight into the biological role of Hsp90 in BmNPV infection in Bombyx mori. J Proteomics 2019; 203:103379. [PMID: 31102755 DOI: 10.1016/j.jprot.2019.103379] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 04/14/2019] [Accepted: 05/06/2019] [Indexed: 12/14/2022]
Abstract
Heat shock protein 90, an essential chaperone responsible for the correct maturation of key proteins, has been confirmed to facilitate Bombyx mori nucleopolyhedrovirus (BmNPV) proliferation but the mechanism is not clear. In this study, we use quantitative proteomics analysis to investigate the mechanism of Hsp90 in BmNPV replication. In total, 195 differentially expressed proteins (DEPs) were identified with 136 up-regulated proteins and 59 down-regulated proteins. The protein expression level of small heat shock proteins, immune-related proteins, cellular DNA repair-related proteins and zinc finger proteins is significantly enhanced while that of protein kinases is declined. KEGG pathway analysis reveals that DEPs are involved in longevity regulating pathway, mTOR signaling pathway, FoxO signaling pathway and Toll and Imd signaling pathway. Based on the DEPs results, we speculate that inhibition of Hsp90 suppresses the BmNPV infection may because it could not only stimulate the host innate immune, induce small heat shock proteins expression to maintain the cellular proteostasis but activate host transcription factors to bind to virus DNA or protein and subsequently hinder virus replication. The results will help understand the roles of Hsp90 in BmNPV infection and shed light on new clue to illustrate the molecular mechanism of silkworm-virus interaction. SIGNIFICANCE: This is the first report on Hsp90 roles in BmNPV infection based on proteomic analysis. Our findings may provide new clue and research orientation to illustrate the molecular mechanism of silkworm-virus interaction and a set of BmHsp90 candidate clients, which may involve in BmNPV infection in BmN cells.
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15
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Jiao Y, Ahmed U, Sim MFM, Bejar A, Zhang X, Talukder MMU, Rice R, Flannick J, Podgornaia AI, Reilly DF, Engreitz JM, Kost-Alimova M, Hartland K, Mercader JM, Georges S, Wagh V, Tadin-Strapps M, Doench JG, Edwardson JM, Rochford JJ, Rosen ED, Majithia AR. Discovering metabolic disease gene interactions by correlated effects on cellular morphology. Mol Metab 2019; 24:108-119. [PMID: 30940487 PMCID: PMC6531784 DOI: 10.1016/j.molmet.2019.03.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 03/06/2019] [Accepted: 03/07/2019] [Indexed: 12/26/2022] Open
Abstract
Objective Impaired expansion of peripheral fat contributes to the pathogenesis of insulin resistance and Type 2 Diabetes (T2D). We aimed to identify novel disease–gene interactions during adipocyte differentiation. Methods Genes in disease-associated loci for T2D, adiposity and insulin resistance were ranked according to expression in human adipocytes. The top 125 genes were ablated in human pre-adipocytes via CRISPR/CAS9 and the resulting cellular phenotypes quantified during adipocyte differentiation with high-content microscopy and automated image analysis. Morphometric measurements were extracted from all images and used to construct morphologic profiles for each gene. Results Over 107 morphometric measurements were obtained. Clustering of the morphologic profiles accross all genes revealed a group of 14 genes characterized by decreased lipid accumulation, and enriched for known lipodystrophy genes. For two lipodystrophy genes, BSCL2 and AGPAT2, sub-clusters with PLIN1 and CEBPA identifed by morphological similarity were validated by independent experiments as novel protein–protein and gene regulatory interactions. Conclusions A morphometric approach in adipocytes can resolve multiple cellular mechanisms for metabolic disease loci; this approach enables mechanistic interrogation of the hundreds of metabolic disease loci whose function still remains unknown. Loss-of-function genetic screen in human adipocytes for 125 genes selected from metabolic disease-associated loci. Genetic screen read out by cellular morphometry— 77,000 images taken with 400 morphological features extracted per image. Pairwise mechanistic interactions between genes identified by correlations of cellular morphometry—two interactions validated. Novel interaction between BSCL2 and PLIN1 from biophysical association of proteins at lipid droplet surface. Novel interaction between CEBPA and AGPAT2 from CEBPA dependent transcription of AGPAT2.
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Affiliation(s)
- Yang Jiao
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Umer Ahmed
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - M F Michelle Sim
- University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, CB2 0QQ, UK
| | - Andrea Bejar
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Xiaolan Zhang
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | | | - Robert Rice
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Jason Flannick
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Anna I Podgornaia
- Genetics and Pharmacogenomics, Merck & Co., Inc., Boston, MA 02115, USA
| | - Dermot F Reilly
- Genetics and Pharmacogenomics, Merck & Co., Inc., Boston, MA 02115, USA
| | | | | | - Kate Hartland
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | | | - Sara Georges
- Genetics and Pharmacogenomics, Merck & Co., Inc., Boston, MA 02115, USA
| | - Vilas Wagh
- Genetics and Pharmacogenomics, Merck & Co., Inc., Boston, MA 02115, USA
| | | | - John G Doench
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | | | - Justin J Rochford
- University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, CB2 0QQ, UK; Rowett Institute and the Aberdeen Cardiovascular and Diabetes Centre, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Evan D Rosen
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Division of Endocrinology, Diabetes and Obesity, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA; Harvard Medical School, Department of Genetics, Boston, MA 02215, USA
| | - Amit R Majithia
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Division of Endocrinology, Department of Medicine, University of California San Diego, La Jolla, CA 92093, USA.
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Nyakundi DO, Bentley SJ, Boshoff A. Hsp70 Escort Protein: More Than a Regulator of Mitochondrial Hsp70. CURR PROTEOMICS 2018. [DOI: 10.2174/1570164615666180713104919] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Hsp70 members occupy a central role in proteostasis and are found in different eukaryotic
cellular compartments. The mitochondrial Hsp70/J-protein machinery performs multiple functions vital
for the proper functioning of the mitochondria, including forming part of the import motor that
transports proteins from the cytosol into the matrix and inner membrane, and subsequently folds these
proteins in the mitochondria. However, unlike other Hsp70s, mitochondrial Hsp70 (mtHsp70) has the
propensity to self-aggregate, accumulating as insoluble aggregates. The self-aggregation of mtHsp70 is
caused by both interdomain and intramolecular communication within the ATPase and linker domains.
Since mtHsp70 is unable to fold itself into an active conformation, it requires an Hsp70 escort protein
(Hep) to both inhibit self-aggregation and promote the correct folding. Hep1 orthologues are present in
the mitochondria of many eukaryotic cells but are absent in prokaryotes. Hep1 proteins are relatively
small and contain a highly conserved zinc-finger domain with one tetracysteine motif that is essential
for binding zinc ions and maintaining the function and solubility of the protein. The zinc-finger domain
lies towards the C-terminus of Hep1 proteins, with very little conservation outside of this domain.
Other than maintaining mtHsp70 in a functional state, Hep1 proteins play a variety of other roles in the
cell and have been proposed to function as both chaperones and co-chaperones. The cellular
localisation and some of the functions are often speculative and are not common to all Hep1 proteins
analysed to date.
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Affiliation(s)
- David O. Nyakundi
- Biotechnology Innovation Centre, Rhodes University, Grahamstown 6140, South Africa
| | - Stephen J. Bentley
- Biotechnology Innovation Centre, Rhodes University, Grahamstown 6140, South Africa
| | - Aileen Boshoff
- Biotechnology Innovation Centre, Rhodes University, Grahamstown 6140, South Africa
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Del Giudice A, Galantini L, Dicko C, Pavel NV. The effect of fatty acid binding in the acid isomerizations of albumin investigated with a continuous acidification method. Colloids Surf B Biointerfaces 2018; 168:109-116. [DOI: 10.1016/j.colsurfb.2018.03.038] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 03/21/2018] [Accepted: 03/24/2018] [Indexed: 10/17/2022]
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Khan MS, Ahmed A, Tabrez S, Islam BU, Rabbani N, Malik A, Ismael MA, Alsenaidy MA, Alsenaidy AM. Optimization of expression and purification of human mortalin (Hsp70): Folding/unfolding analysis. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2017; 187:98-103. [PMID: 28666159 DOI: 10.1016/j.saa.2017.06.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Revised: 06/02/2017] [Accepted: 06/07/2017] [Indexed: 06/07/2023]
Abstract
Human mortalin is a Hsp70 mitochondrial protein that plays an essential role in the biogenesis of mitochondria. The deregulation of mortalin expression and its functions could lead to several age-associated disorders and some types of cancers. In the present study, we optimized the expression and purification of recombinant human mortalin by the use of two-step chromatography. Low temperature (18°C) and 0.5mM (IPTG) was required for optimum mortalin expression. Chaperone activity of mortalin was assessed by the citrate synthase and insulin protection assay, which suggested their protective role in mitochondria. Folding and unfolding assessments of mortalin were carried out in the presence of guanidine hydrochloride (GdnHCl) by intrinsic fluorescence measurement, ANS (8-analino 1-nephthlene sulfonic acid) binding and CD (circular dichroism) analysis. Under denaturing conditions, mortalin showed decrease in tryptophan fluorescence intensity along with a red shift of 11nm. Moreover, ANS binding studies illustrated decrease in hydrophobicity. CD measurement of mortalin showed a predominant helical structure. However, the secondary structure was lost at low concentration of GdnHCl (1M). We present a simple and robust method to produce soluble mortalin and warranted that chaperones are also susceptible to unfolding and futile to maintain protein homeostasis.
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Affiliation(s)
- Mohd Shahnawaz Khan
- Department of Biochemistry, College of Sciences, King Saud University, Riyadh, Saudi Arabia.
| | - Anwar Ahmed
- Department of Biochemistry, College of Sciences, King Saud University, Riyadh, Saudi Arabia
| | - Shams Tabrez
- King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Badar Ul Islam
- Department of Biochemistry, J. N. Medical College, Aligarh Muslim University, Aligarh, India
| | - Nayyar Rabbani
- Department of Biochemistry, College of Sciences, King Saud University, Riyadh, Saudi Arabia
| | - Ajamaluddin Malik
- Department of Biochemistry, College of Sciences, King Saud University, Riyadh, Saudi Arabia
| | - Mohamad A Ismael
- Department of Biochemistry, College of Sciences, King Saud University, Riyadh, Saudi Arabia
| | - Mohammad A Alsenaidy
- Department of Pharmaceutics, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
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Structural and functional studies of the Leishmania braziliensis mitochondrial Hsp70: Similarities and dissimilarities to human orthologues. Arch Biochem Biophys 2016; 613:43-52. [PMID: 27840097 DOI: 10.1016/j.abb.2016.11.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Revised: 11/08/2016] [Accepted: 11/09/2016] [Indexed: 12/14/2022]
Abstract
Heat shock protein 70 kDa (Hsp70) is a conserved molecular chaperone family involved in several functions related to protein homeostasis. In eukaryotes, Hsp70 homologues are found in all cell compartments. The mitochondrial Hsp70 isoform (mtHsp70) is involved in import of mitochondrial matrix proteins as well as their folding and maturation. Moreover, mtHsp70 has the propensity to self-aggregate, and it depends on the action of the co-chaperone Hsp70-escort protein 1 (Hep1) to be produced functional. Here, we analyze the solution structure and function of mtHsp70 of Leishmania braziliensis (LbmtHsp70). This recombinant protein was obtained folded, in the monomeric state and it has an elongated shape. We observed that LbmtHsp70 suffers thermal aggregation that depends on the protein concentration and is composed of domains with different thermal stabilities. LbmtHsp70 interacted with adenosine nucleotides with a thermodynamic signature different from those reported for human orthologues and interacted, driven by both enthalpy and entropy, with L. braziliensis Hep1 (LbHep1) with a nanomolar dissociation constant. Moreover, LbHep1 stimulated the LbmtHsp70 ATPase activity. Since little is known about mitochondrial Hsp70, particularly in protozoa, we believe that our data are of interest for understanding protozoan Hsp70 machinery.
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20
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Borges JC, Seraphim TV, Dores-Silva PR, Barbosa LRS. A review of multi-domain and flexible molecular chaperones studies by small-angle X-ray scattering. Biophys Rev 2016; 8:107-120. [PMID: 28510050 PMCID: PMC5425780 DOI: 10.1007/s12551-016-0194-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 02/02/2016] [Indexed: 02/06/2023] Open
Abstract
Intrinsic flexibility is closely related to protein function, and a plethora of important regulatory proteins have been found to be flexible, multi-domain or even intrinsically disordered. On the one hand, understanding such systems depends on how these proteins behave in solution. On the other, small-angle X-ray scattering (SAXS) is a technique that fulfills the requirements to study protein structure and dynamics relatively quickly with few experimental limitations. Molecular chaperones from Hsp70 and Hsp90 families are multi-domain proteins containing flexible and/or disordered regions that play central roles in cellular proteostasis. Here, we review the structure and function of these proteins by SAXS. Our general approach includes the use of SAXS data to determine size and shape parameters, as well as protein shape reconstruction and their validation by using accessory biophysical tools. Some remarkable examples are presented that exemplify the potential of the SAXS technique. Protein structure can be determined in solution even at limiting protein concentrations (for example, human mortalin, a mitochondrial Hsp70 chaperone). The protein organization, flexibility and function (for example, the J-protein co-chaperones), oligomeric status, domain organization, and flexibility (for the Hsp90 chaperone and the Hip and Hep1 co-chaperones) may also be determined. Lastly, the shape, structural conservation, and protein dynamics (for the Hsp90 chaperone and both p23 and Aha1 co-chaperones) may be studied by SAXS. We believe this review will enhance the application of the SAXS technique to the study of the molecular chaperones.
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Affiliation(s)
- Júlio C Borges
- Instituto de Química de São Carlos, Universidade de São Paulo, São Carlos, SP, Brazil.
| | - Thiago V Seraphim
- Instituto de Química de São Carlos, Universidade de São Paulo, São Carlos, SP, Brazil
| | - Paulo R Dores-Silva
- Instituto de Química de São Carlos, Universidade de São Paulo, São Carlos, SP, Brazil
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Dores-Silva PR, Beloti LL, Minari K, Silva SMO, Barbosa LRS, Borges JC. Structural and functional studies of Hsp70-escort protein--Hep1--of Leishmania braziliensis. Int J Biol Macromol 2015; 79:903-12. [PMID: 26071939 DOI: 10.1016/j.ijbiomac.2015.05.042] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Revised: 05/22/2015] [Accepted: 05/23/2015] [Indexed: 12/14/2022]
Abstract
Hep1 is a mitochondrial Hsp70 (mtHsp70) co-chaperone that presents a zinc finger domain essential for its function. This co-chaperone acts to maintain mtHsp70 in its soluble and functional state. In this work, we have demonstrated that Leishmania braziliensis mtHsp70 (LbmtHsp70) is also dependent on the assistance of Hep1. To understand the L. braziliensis Hep1 (LbHep1) structure-function relationship, we produced LbHep1 and two truncated mutants corresponding to the C-terminal zinc finger domain and the N-terminal region. We observed that LbHep1 is composed of an unfolded N-terminal region and a β-sheet-folded C-terminal domain, which holds the zinc-binding motif. Both LbHep1 and the zinc finger domain construction maintained LbmtHsp70 solubility in co-expression systems after cell lysis. In solution, LbHep1 behaved as a highly elongated monomer, probably due to the unfolded N-terminal region. Furthermore, we also observed that the zinc ion interacted with LbHep1 with high affinity and was critical for LbHep1 structure and stability because its removal from LbHep1 solutions altered the protein structure and stability. In vitro, LbHep1 protected, in sub-stoichiometric fashion, LbmtHsp70 from thermally induced aggregation but did not present intrinsic chaperone activity on model client proteins. Therefore, LbHep1 is a specific chaperone for LbmtHsp70.
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Affiliation(s)
- P R Dores-Silva
- Institute of Chemistry of São Carlos, University of São Paulo - USP, São Carlos, SP 13560-970, Brazil
| | - L L Beloti
- Institute of Chemistry of São Carlos, University of São Paulo - USP, São Carlos, SP 13560-970, Brazil
| | - K Minari
- Institute of Chemistry of São Carlos, University of São Paulo - USP, São Carlos, SP 13560-970, Brazil; Post-Graduation Program in Evolutionary Genetics and Molecular Biology, Federal University of São Carlos - UFSCar, São Carlos, SP 13565-905, Brazil
| | - S M O Silva
- Institute of Chemistry of São Carlos, University of São Paulo - USP, São Carlos, SP 13560-970, Brazil
| | - L R S Barbosa
- Institute of Physics, University of São Paulo - USP, São Paulo, SP 05508-090, Brazil
| | - J C Borges
- Institute of Chemistry of São Carlos, University of São Paulo - USP, São Carlos, SP 13560-970, Brazil.
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Dores-Silva PR, Barbosa LRS, Ramos CHI, Borges JC. Human mitochondrial Hsp70 (mortalin): shedding light on ATPase activity, interaction with adenosine nucleotides, solution structure and domain organization. PLoS One 2015; 10:e0117170. [PMID: 25615450 PMCID: PMC4304843 DOI: 10.1371/journal.pone.0117170] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2014] [Accepted: 12/19/2014] [Indexed: 12/28/2022] Open
Abstract
The human mitochondrial Hsp70, also called mortalin, is of considerable importance for mitochondria biogenesis and the correct functioning of the cell machinery. In the mitochondrial matrix, mortalin acts in the importing and folding process of nucleus-encoded proteins. The in vivo deregulation of mortalin expression and/or function has been correlated with age-related diseases and certain cancers due to its interaction with the p53 protein. In spite of its critical biological roles, structural and functional studies on mortalin are limited by its insoluble recombinant production. This study provides the first report of the production of folded and soluble recombinant mortalin when co-expressed with the human Hsp70-escort protein 1, but it is still likely prone to self-association. The monomeric fraction of mortalin presented a slightly elongated shape and basal ATPase activity that is higher than that of its cytoplasmic counterpart Hsp70-1A, suggesting that it was obtained in the functional state. Through small angle X-ray scattering, we assessed the low-resolution structural model of monomeric mortalin that is characterized by an elongated shape. This model adequately accommodated high resolution structures of Hsp70 domains indicating its quality. We also observed that mortalin interacts with adenosine nucleotides with high affinity. Thermally induced unfolding experiments indicated that mortalin is formed by at least two domains and that the transition is sensitive to the presence of adenosine nucleotides and that this process is dependent on the presence of Mg2+ ions. Interestingly, the thermal-induced unfolding assays of mortalin suggested the presence of an aggregation/association event, which was not observed for human Hsp70-1A, and this finding may explain its natural tendency for in vivo aggregation. Our study may contribute to the structural understanding of mortalin as well as to contribute for its recombinant production for antitumor compound screenings.
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Affiliation(s)
- Paulo R Dores-Silva
- Institute of Chemistry of Sao Carlos, University of Sao Paulo, Sao Carlos, SP, P.O. Box 780, 13560-970, Brazil
| | - Leandro R S Barbosa
- Institute of Physics, University of Sao Paulo, Sao Paulo, SP, 05508-090, Brazil
| | - Carlos H I Ramos
- Institute of Chemistry, University of Campinas-UNICAMP, P.O. Box 6154, 13083-970, Campinas, SP, Brazil
| | - Júlio C Borges
- Institute of Chemistry of Sao Carlos, University of Sao Paulo, Sao Carlos, SP, P.O. Box 780, 13560-970, Brazil
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A content and structural assessment of oxidative motifs across a diverse set of life forms. Comput Biol Med 2014; 53:179-89. [PMID: 25151511 DOI: 10.1016/j.compbiomed.2014.07.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Revised: 06/14/2014] [Accepted: 07/16/2014] [Indexed: 11/24/2022]
Abstract
Exposure to weightlessness (microgravity) or other protein stresses are detrimental to animal and human protein tissue health. Protein damage has been associated with stress and is linked to aging and the onset of diseases such as Alzheimer׳s, Parkinson׳s, sepsis, and others. Protein stresses may cause alterations to physical protein structure, altering its functional identity. Alterations from stresses such as microgravity may be responsible for forms of muscle atrophy (as noted in returning astronauts), however, protein stresses come from other sources as well. Oxidative carbonylation is a protein stress which is a driving force behind protein decay and is attracted to protein segments enriched in R, K, P, T, E and S residues. Since mitochondria apply oxidative processes to produce ATP, their proteins may be placed in the same danger as those that are exposed to stresses. However, they do not appear to be impacted in the same way. Across 14 diverse organisms, we evaluate the coverage of motifs which are high in the amino acids thought to be affected by protein stresses such as oxidation. For this study, we study RKPT and PEST motifs which are both responsible for attracting forms of oxidation across mitochondrial and non-mitochondrial proteins. We show that mitochondrial proteins have fewer of these oxidative sites compared to non-mitochondrial proteins. Additionally, we analyze the oxidative regions to determine that their motifs preferentially tend to make up the connection points between the four kinds of structures of folded proteins (helices, turns, sheets, and coils).
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