1
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Wang J, Guo X, Chen Y, Liu T, Zhu J, Xu S, Vierling E. Maternal nitric oxide homeostasis impacts female gametophyte development under optimal and stress conditions. Plant Cell 2024:koae043. [PMID: 38376990 DOI: 10.1093/plcell/koae043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Revised: 01/08/2024] [Accepted: 01/11/2024] [Indexed: 02/22/2024]
Abstract
In adverse environments, the number of fertilizable female gametophytes (FGs) in plants is reduced, leading to increased survival of remaining offspring. How the maternal plant perceives internal growth cues and external stress conditions to alter FG development remains largely unknown. We report that homeostasis of the stress signaling molecule nitric oxide (NO) plays a key role in controlling FG development under both optimal and stress conditions. NO homeostasis is precisely regulated by S-nitrosoglutathione reductase (GSNOR). Prior to fertilization, GSNOR protein is exclusively accumulated in sporophytic tissues and indirectly controls FG development in Arabidopsis (Arabidopsis thaliana). In GSNOR null mutants, NO species accumulated in the degenerating sporophytic nucellus and auxin efflux into the developing FG was restricted, which inhibited FG development, resulting in reduced fertility. Importantly, restoring GSNOR expression in maternal, but not gametophytic tissues, or increasing auxin efflux substrate significantly increased the proportion of normal FGs and fertility. Furthermore, GSNOR overexpression or added auxin efflux substrate increased fertility under drought and salt stress. These data indicate that NO homeostasis is critical to normal auxin transport and maternal control of FG development, which in turn determine seed yield. Understanding this aspect of fertility control could contribute to mediating yield loss under adverse conditions.
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Affiliation(s)
- Junzhe Wang
- State Key Laboratory for Crop Stress Resistance and High-Efficiency Production, College of Agronomy, Northwest A&F University, Yangling, Shaanxi 712100, China
- Hainan Yazhou Bay Seed Laboratory, Yazhou, Sanya 572025, China
| | - Xiaolong Guo
- State Key Laboratory for Crop Stress Resistance and High-Efficiency Production, College of Agronomy, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Yijin Chen
- State Key Laboratory for Crop Stress Resistance and High-Efficiency Production, College of Agronomy, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Tianxiang Liu
- State Key Laboratory for Crop Stress Resistance and High-Efficiency Production, College of Agronomy, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Jianchu Zhu
- State Key Laboratory for Crop Stress Resistance and High-Efficiency Production, College of Agronomy, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Shengbao Xu
- State Key Laboratory for Crop Stress Resistance and High-Efficiency Production, College of Agronomy, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Elizabeth Vierling
- Department of Biochemistry & Molecular Biology, University of Massachusetts, Amherst, MA 01003, USA
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2
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Meloni M, Rossi J, Fanti S, Carloni G, Tedesco D, Treffon P, Piccinini L, Falini G, Trost P, Vierling E, Licausi F, Giuntoli B, Musiani F, Fermani S, Zaffagnini M. Structural and biochemical characterization of Arabidopsis alcohol dehydrogenases reveals distinct functional properties but similar redox sensitivity. Plant J 2024. [PMID: 38308388 DOI: 10.1111/tpj.16651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 01/07/2024] [Accepted: 01/18/2024] [Indexed: 02/04/2024]
Abstract
Alcohol dehydrogenases (ADHs) are a group of zinc-binding enzymes belonging to the medium-length dehydrogenase/reductase (MDR) protein superfamily. In plants, these enzymes fulfill important functions involving the reduction of toxic aldehydes to the corresponding alcohols (as well as catalyzing the reverse reaction, i.e., alcohol oxidation; ADH1) and the reduction of nitrosoglutathione (GSNO; ADH2/GSNOR). We investigated and compared the structural and biochemical properties of ADH1 and GSNOR from Arabidopsis thaliana. We expressed and purified ADH1 and GSNOR and determined two new structures, NADH-ADH1 and apo-GSNOR, thus completing the structural landscape of Arabidopsis ADHs in both apo- and holo-forms. A structural comparison of these Arabidopsis ADHs revealed a high sequence conservation (59% identity) and a similar fold. In contrast, a striking dissimilarity was observed in the catalytic cavity supporting substrate specificity and accommodation. Consistently, ADH1 and GSNOR showed strict specificity for their substrates (ethanol and GSNO, respectively), although both enzymes had the ability to oxidize long-chain alcohols, with ADH1 performing better than GSNOR. Both enzymes contain a high number of cysteines (12 and 15 out of 379 residues for ADH1 and GSNOR, respectively) and showed a significant and similar responsivity to thiol-oxidizing agents, indicating that redox modifications may constitute a mechanism for controlling enzyme activity under both optimal growth and stress conditions.
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Affiliation(s)
- Maria Meloni
- Department of Pharmacy and Biotechnology, University of Bologna, 40126, Bologna, Italy
| | - Jacopo Rossi
- Department of Pharmacy and Biotechnology, University of Bologna, 40126, Bologna, Italy
| | - Silvia Fanti
- Department of Chemistry "G. Ciamician", University of Bologna, 40126, Bologna, Italy
| | - Giacomo Carloni
- Department of Chemistry "G. Ciamician", University of Bologna, 40126, Bologna, Italy
| | - Daniele Tedesco
- Institute for Organic Synthesis and Photoreactivity (ISOF), National Research Council of Italy (CNR), 40129, Bologna, Italy
| | - Patrick Treffon
- Department of Biochemistry and Molecular Biology, University of Massachusetts Amherst, Amherst, Massachusetts, USA
| | - Luca Piccinini
- Department of Biology, University of Pisa, Pisa, 56127, Italy
- Center for Plant Sciences, Scuola Superiore Sant'Anna, Pisa, 56124, Italy
| | - Giuseppe Falini
- Department of Chemistry "G. Ciamician", University of Bologna, 40126, Bologna, Italy
| | - Paolo Trost
- Department of Pharmacy and Biotechnology, University of Bologna, 40126, Bologna, Italy
| | - Elizabeth Vierling
- Department of Biochemistry and Molecular Biology, University of Massachusetts Amherst, Amherst, Massachusetts, USA
| | | | - Beatrice Giuntoli
- Department of Biology, University of Pisa, Pisa, 56127, Italy
- Center for Plant Sciences, Scuola Superiore Sant'Anna, Pisa, 56124, Italy
| | - Francesco Musiani
- Department of Pharmacy and Biotechnology, University of Bologna, 40126, Bologna, Italy
| | - Simona Fermani
- Department of Chemistry "G. Ciamician", University of Bologna, 40126, Bologna, Italy
- Interdepartmental Centre for Industrial Research Health Sciences & Technologies, University of Bologna, 40064, Bologna, Italy
| | - Mirko Zaffagnini
- Department of Pharmacy and Biotechnology, University of Bologna, 40126, Bologna, Italy
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3
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Zhu L, Scafaro AP, Vierling E, Ball MC, Posch BC, Stock F, Atkin OK. Heat tolerance of a tropical-subtropical rainforest tree species Polyscias elegans: time-dependent dynamic responses of physiological thermostability and biochemistry. New Phytol 2024; 241:715-731. [PMID: 37932881 DOI: 10.1111/nph.19356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 10/01/2023] [Indexed: 11/08/2023]
Abstract
Heat stress interrupts physiological thermostability and triggers biochemical responses that are essential for plant survival. However, there is limited knowledge on the speed plants adjust to heat in hours and days, and which adjustments are crucial. Tropical-subtropical rainforest tree species (Polyscias elegans) were heated at 40°C for 5 d, before returning to 25°C for 13 d of recovery. Leaf heat tolerance was quantified using the temperature at which minimal chl a fluorescence sharply rose (Tcrit ). Tcrit , metabolites, heat shock protein (HSP) abundance and membrane lipid fatty acid (FA) composition were quantified. Tcrit increased by 4°C (48-52°C) within 2 h of 40°C exposure, along with rapid accumulation of metabolites and HSPs. By contrast, it took > 2 d for FA composition to change. At least 2 d were required for Tcrit , HSP90, HSP70 and FAs to return to prestress levels. The results highlight the multi-faceted response of P. elegans to heat stress, and how this response varies over the scale of hours to days, culminating in an increased level of photosynthetic heat tolerance. These responses are important for survival of plants when confronted with heat waves amidst ongoing global climate change.
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Affiliation(s)
- Lingling Zhu
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Forestry, Nanjing Forestry University, 159 Longpan Road, Nanjing, 210037, China
- ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, Building 134, The Australian National University, Canberra, ACT, 2601, Australia
- Division of Plant Sciences, Research School of Biology, Building 46, The Australian National University, Canberra, ACT, 2601, Australia
| | - Andrew P Scafaro
- ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, Building 134, The Australian National University, Canberra, ACT, 2601, Australia
- Division of Plant Sciences, Research School of Biology, Building 46, The Australian National University, Canberra, ACT, 2601, Australia
| | - Elizabeth Vierling
- Department of Biochemistry and Molecular Biology, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Marilyn C Ball
- Division of Plant Sciences, Research School of Biology, Building 46, The Australian National University, Canberra, ACT, 2601, Australia
| | - Bradley C Posch
- ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, Building 134, The Australian National University, Canberra, ACT, 2601, Australia
- Division of Plant Sciences, Research School of Biology, Building 46, The Australian National University, Canberra, ACT, 2601, Australia
- Department of Research, Conservation, and Collections, Desert Botanical Garden, Phoenix, AZ, 85008, USA
| | - Frederike Stock
- Division of Plant Sciences, Research School of Biology, Building 46, The Australian National University, Canberra, ACT, 2601, Australia
- Australian Plant Phenomics Facility, Research School of Biology, Building 134, The Australian National University, Canberra, ACT, 2601, Australia
| | - Owen K Atkin
- ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, Building 134, The Australian National University, Canberra, ACT, 2601, Australia
- Division of Plant Sciences, Research School of Biology, Building 46, The Australian National University, Canberra, ACT, 2601, Australia
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4
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Waters ER, Bezanilla M, Vierling E. ATAD3 Proteins: Unique Mitochondrial Proteins Essential for Life in Diverse Eukaryotic Lineages. Plant Cell Physiol 2023:pcad122. [PMID: 37859594 DOI: 10.1093/pcp/pcad122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 10/05/2023] [Accepted: 10/10/2023] [Indexed: 10/21/2023]
Abstract
ATAD3 proteins (ATPase family AAA domain-containing protein 3) are unique mitochondrial proteins that arose deep in the eukaryotic lineage but that are surprisingly absent from the Fungi and Amoebozoa. These ~600 amino acid proteins are anchored in the inner mitochondrial membrane and are essential in metazoans and Arabidopsis thaliana. ATAD3s comprise a C-terminal AAA+ matrix domain and an ATAD3_N domain that is located primarily in the inner membrane space but potentially extends into cytosol to interact with the ER. Sequence and structural alignments indicate ATAD3 proteins are most similar to classic chaperone unfoldases in AAA+ family, suggesting that they operate in mitochondrial protein quality control. A. thaliana has four ATAD3 genes in two distinct clades that appear first in the seed plants, and both clades are essential for viability. The four genes are generally coordinately expressed, and transcripts are highest in growing apices and imbibed seeds. Plants with disrupted ATAD3 have reduced growth, aberrant mitochondrial morphology, diffuse nucleoids and reduced oxidative phosphorylation complex I. These and other pleiotropic phenotypes are also observed in ATAD3 mutants in metazoans. Here we discuss the distribution of ATAD3 proteins as they have evolved in the plant kingdom, their unique structure, what we know about their function in plants, and the challenges in determining their essential roles in mitochondria.
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Affiliation(s)
- Elizabeth R Waters
- Department of Biology, San Diego State University, San Diego, CA 92182-4614, USA
| | - Magdalena Bezanilla
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755, USA
| | - Elizabeth Vierling
- Department of Biochemistry & Molecular Biology, University of Massachusetts Amherst, Amherst, MA 01003, USA
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5
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Kim M, Swenson J, McLoughlin F, Vierling E. Mutation of the polyadenylation complex subunit CstF77 reveals that mRNA 3' end formation and HSP101 levels are critical for a robust heat stress response. Plant Cell 2023; 35:924-941. [PMID: 36472129 PMCID: PMC9940869 DOI: 10.1093/plcell/koac351] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 12/03/2022] [Indexed: 06/17/2023]
Abstract
Heat shock protein 101 (HSP101) in plants, and bacterial and yeast orthologs, is essential for thermotolerance. To investigate thermotolerance mechanisms involving HSP101, we performed a suppressor screen in Arabidopsis thaliana of a missense HSP101 allele (hot1-4). hot1-4 plants are sensitive to acclimation heat treatments that are otherwise permissive for HSP101 null mutants, indicating that the hot1-4 protein is toxic. We report one suppressor (shot2, suppressor of hot1-4 2) has a missense mutation of a conserved residue in CLEAVAGE STIMULATION FACTOR77 (CstF77), a subunit of the polyadenylation complex critical for mRNA 3' end maturation. We performed ribosomal RNA depletion RNA-Seq and captured transcriptional readthrough with a custom bioinformatics pipeline. Acclimation heat treatment caused transcriptional readthrough in hot1-4 shot2, with more readthrough in heat-induced genes, reducing the levels of toxic hot1-4 protein and suppressing hot1-4 heat sensitivity. Although shot2 mutants develop like the wild type in the absence of stress and survive mild heat stress, reduction of heat-induced genes and decreased HSP accumulation makes shot2 in HSP101 null and wild-type backgrounds sensitive to severe heat stress. Our study reveals the critical function of CstF77 for 3' end formation of mRNA and the dominant role of HSP101 in dictating the outcome of severe heat stress.
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Affiliation(s)
- Minsoo Kim
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, Massachusetts 01003, USA
| | - John Swenson
- Program for Organismic and Evolutionary Biology, University of Massachusetts, Amherst, Massachusetts 01003, USA
| | - Fionn McLoughlin
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, Massachusetts 01003, USA
| | - Elizabeth Vierling
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, Massachusetts 01003, USA
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6
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Treffon P, Rossi J, Gabellini G, Trost P, Zaffagnini M, Vierling E. Proteome profiling of a S‐Nitrosoglutathione reductase (GSNOR) null mutant reveals that aldo‐keto reductases form a new class of enzymes involved in nitric oxide homeostasis. FASEB J 2022. [DOI: 10.1096/fasebj.2022.36.s1.r2519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Patrick Treffon
- Department of Biochemistry and Molecular BiologyUniversity of Massachusetts AmherstAmherstMA
| | - Jacopo Rossi
- Department of Pharmacy and BiotechnologiesUniversity of BolognaBologna
| | | | - Paolo Trost
- Department of Pharmacy and BiotechnologiesUniversity of BolognaBologna
| | - Mirko Zaffagnini
- Department of Pharmacy and BiotechnologiesUniversity of BolognaBologna
| | - Elizabeth Vierling
- Department of Biochemistry and Molecular BiologyUniversity of Massachusetts AmherstAmherstMA
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7
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Suri‐Payer F, Patel P, Vierling E. Assessing the Importance of Chloroplast and Mitochondrial Small Heat Shock Proteins in Arabidopsis thaliana. FASEB J 2022. [DOI: 10.1096/fasebj.2022.36.s1.r4277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Fabian Suri‐Payer
- Biochemistry & Molecular BiologyUniversity of Massachusetts AmherstAmherstMA
| | - Parth Patel
- Biochemistry & Molecular BiologyUniversity of Massachusetts AmherstAmherstMA
| | - Elizabeth Vierling
- Biochemistry & Molecular BiologyUniversity of Massachusetts AmherstAmherstMA
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8
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Kaur Y, Treffon P, Vierling E. Proteins Interacting with S‐Nitrosoglutathione reductase to Regulate Nitric Oxide Homeostasis. FASEB J 2022. [DOI: 10.1096/fasebj.2022.36.s1.r3078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Yadwinder Kaur
- Biochemistry and Molecular BiologyUniversity of Massachusetts AmherstWeymouthMA
| | - Patrick Treffon
- Biochemistry and Molecular BiologyUniversity of Massachusetts AmherstAmherstMA
| | - Elizabeth Vierling
- Biochemistry and Molecular BiologyUniversity of Massachusetts AmherstAmherstMA
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9
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Treffon P, Rossi J, Gabellini G, Trost P, Zaffagnini M, Vierling E. Quantitative Proteome Profiling of a S-Nitrosoglutathione Reductase (GSNOR) Null Mutant Reveals a New Class of Enzymes Involved in Nitric Oxide Homeostasis in Plants. Front Plant Sci 2021; 12:787435. [PMID: 34956283 PMCID: PMC8695856 DOI: 10.3389/fpls.2021.787435] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 11/15/2021] [Indexed: 06/14/2023]
Abstract
Nitric oxide (NO) is a short-lived radical gas that acts as a signaling molecule in all higher organisms, and that is involved in multiple plant processes, including germination, root growth, and fertility. Regulation of NO-levels is predominantly achieved by reaction of oxidation products of NO with glutathione to form S-nitrosoglutathione (GSNO), the principal bioactive form of NO. The enzyme S-nitrosoglutathione reductase (GSNOR) is a major route of NADH-dependent GSNO catabolism and is critical to NO homeostasis. Here, we performed a proteomic analysis examining changes in the total leaf proteome of an Arabidopsis thaliana GSNOR null mutant (hot5-2/gsnor1-3). Significant increases or decreases in proteins associated with chlorophyll metabolism and with redox and stress metabolism provide insight into phenotypes observed in hot5-2/gsnor1-3 plants. Importantly, we identified a significant increase in proteins that belong to the aldo-keto reductase (AKR) protein superfamily, AKR4C8 and 9. Because specific AKRs have been linked to NO metabolism in mammals, we expressed and purified A. thaliana AKR4C8 and 9 and close homologs AKR4C10 and 11 and determined that they have NADPH-dependent activity in GSNO and S-nitroso-coenzyme A (SNO-CoA) reduction. Further, we found an increase of NADPH-dependent GSNO reduction activity in hot5-2/gsnor1-3 mutant plants. These data uncover a new, NADPH-dependent component of NO metabolism that may be integrated with NADH-dependent GSNOR activity to control NO homeostasis in plants.
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Affiliation(s)
- Patrick Treffon
- Department of Biochemistry and Molecular Biology, University of Massachusetts Amherst, Amherst, MA, United States
| | - Jacopo Rossi
- Department of Pharmacy and Biotechnologies, University of Bologna, Bologna, Italy
| | - Giuseppe Gabellini
- Department of Pharmacy and Biotechnologies, University of Bologna, Bologna, Italy
| | - Paolo Trost
- Department of Pharmacy and Biotechnologies, University of Bologna, Bologna, Italy
| | - Mirko Zaffagnini
- Department of Pharmacy and Biotechnologies, University of Bologna, Bologna, Italy
| | - Elizabeth Vierling
- Department of Biochemistry and Molecular Biology, University of Massachusetts Amherst, Amherst, MA, United States
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10
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Kim M, Schulz V, Brings L, Schoeller T, Kühn K, Vierling E. mTERF18 and ATAD3 are required for mitochondrial nucleoid structure and their disruption confers heat tolerance in Arabidopsis thaliana. New Phytol 2021; 232:2026-2042. [PMID: 34482561 DOI: 10.1111/nph.17717] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 08/23/2021] [Indexed: 05/27/2023]
Abstract
Mitochondria play critical roles in generating ATP through oxidative phosphorylation (OXPHOS) and produce both damaging and signaling reactive oxygen species (ROS). They have reduced genomes that encode essential subunits of the OXPHOS machinery. Mitochondrial Transcription tERmination Factor-related (mTERF) proteins are involved in organelle gene expression, interacting with organellar DNA or RNA. We previously found that mutations in Arabidopsis thaliana mTERF18/SHOT1 enable plants to better tolerate heat and oxidative stresses, presumably due to low ROS production and reduced oxidative damage. Here we discover that shot1 mutants have greatly reduced OXPHOS complexes I and IV and reveal that suppressor of hot1-4 1 (SHOT1) binds DNA and localizes to mitochondrial nucleoids, which are disrupted in shot1. Furthermore, three homologues of animal ATPase family AAA domain-containing protein 3 (ATAD3), which is involved in mitochondrial nucleoid organization, were identified as SHOT1-interacting proteins. Importantly, disrupting ATAD3 function disrupts nucleoids, reduces accumulation of complex I, and enhances heat tolerance, as is seen in shot1 mutants. Our data link nucleoid organization to OXPHOS biogenesis and suggest that the common defects in shot1 mutants and ATAD3-disrupted plants lead to critical changes in mitochondrial metabolism and signaling that result in plant heat tolerance.
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Affiliation(s)
- Minsoo Kim
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, MA, 01003, USA
| | - Vincent Schulz
- Department of Life Sciences, Institute of Biology, Humboldt-Universität zu Berlin, 10099, Berlin, Germany
| | - Lea Brings
- Department of Life Sciences, Institute of Biology, Humboldt-Universität zu Berlin, 10099, Berlin, Germany
| | - Theresa Schoeller
- Department of Plant Physiology, Institute of Biology, Martin-Luther-Universität Halle-Wittenberg, 06120, Halle (Saale), Germany
| | - Kristina Kühn
- Department of Life Sciences, Institute of Biology, Humboldt-Universität zu Berlin, 10099, Berlin, Germany
- Department of Plant Physiology, Institute of Biology, Martin-Luther-Universität Halle-Wittenberg, 06120, Halle (Saale), Germany
| | - Elizabeth Vierling
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, MA, 01003, USA
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11
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Wang J, Guo X, Xiao Q, Zhu J, Cheung AY, Yuan L, Vierling E, Xu S. Corrigendum. New Phytol 2021; 232:958. [PMID: 34397106 PMCID: PMC8565677 DOI: 10.1111/nph.17597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 07/02/2021] [Indexed: 06/13/2023]
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12
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Liu T, Arsenault J, Vierling E, Kim M. Mitochondrial ATP synthase subunit d, a component of the peripheral stalk, is essential for growth and heat stress tolerance in Arabidopsis thaliana. Plant J 2021; 107:713-726. [PMID: 33974298 DOI: 10.1111/tpj.15317] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 04/19/2021] [Accepted: 05/03/2021] [Indexed: 05/11/2023]
Abstract
As rapid changes in climate threaten global crop yields, an understanding of plant heat stress tolerance is increasingly relevant. Heat stress tolerance involves the coordinated action of many cellular processes and is particularly energy demanding. We acquired a knockout mutant and generated knockdown lines in Arabidopsis thaliana of the d subunit of mitochondrial ATP synthase (gene name: ATPQ, AT3G52300, referred to hereafter as ATPd), a subunit of the peripheral stalk, and used these to investigate the phenotypic significance of this subunit in normal growth and heat stress tolerance. Homozygous knockout mutants for ATPd could not be obtained due to gametophytic defects, while heterozygotes possess no visible phenotype. Therefore, we used RNA interference to create knockdown plant lines for further studies. Proteomic analysis and blue native gels revealed that ATPd downregulation impairs only subunits of the mitochondrial ATP synthase (complex V). Knockdown plants were more sensitive to heat stress, had abnormal leaf morphology, and were severely slow growing compared to wild type. These results indicate that ATPd plays a crucial role in proper function of the mitochondrial ATP synthase holoenzyme, which, when reduced, leads to wide-ranging defects in energy-demanding cellular processes. In knockdown plants, more hydrogen peroxide accumulated and mitochondrial dysfunction stimulon (MDS) genes were activated. These data establish the essential structural role of ATPd and support the importance of complex V in normal plant growth, and provide new information about its requirement for heat stress tolerance.
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Affiliation(s)
- Tianxiang Liu
- University of Massachusetts Amherst, Amherst, MA, 01003, USA
- Northwest Agriculture and Forestry University, Yangling, Shaanxi, 712100, China
| | - Jesse Arsenault
- University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | | | - Minsoo Kim
- University of Massachusetts Amherst, Amherst, MA, 01003, USA
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13
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Wang J, Guo X, Xiao Q, Zhu J, Cheung AY, Yuan L, Vierling E, Xu S. Auxin efflux controls orderly nucellar degeneration and expansion of the female gametophyte in Arabidopsis. New Phytol 2021; 230:2261-2274. [PMID: 33338267 PMCID: PMC8248126 DOI: 10.1111/nph.17152] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 12/12/2020] [Indexed: 05/11/2023]
Abstract
The nucellus tissue in flowering plants provides nutrition for the development of the female gametophyte (FG) and young embryo. The nucellus degenerates as the FG develops, but the mechanism controlling the coupled process of nucellar degeneration and FG expansion remains largely unknown. The degeneration process of the nucellus and spatiotemporal auxin distribution in the developing ovule before fertilization were investigated in Arabidopsis thaliana. Nucellar degeneration before fertilization occurs through vacuolar cell death and in an ordered degeneration fashion. This sequential nucellar degeneration is controlled by the signalling molecule auxin. Auxin efflux plays the core role in precisely controlling the spatiotemporal pattern of auxin distribution in the nucellus surrounding the FG. The auxin efflux carrier PIN1 transports maternal auxin into the nucellus while PIN3/PIN4/PIN7 further delivers auxin to degenerating nucellar cells and concurrently controls FG central vacuole expansion. Notably, auxin concentration and auxin efflux are controlled by the maternal tissues, acting as a key communication from maternal to filial tissue.
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Affiliation(s)
- Junzhe Wang
- State Key Laboratory of Crop Stress Biology for Arid AreasCollege of AgronomyNorthwest A&F UniversityYanglingShaanxi712100China
| | - Xiaolong Guo
- State Key Laboratory of Crop Stress Biology for Arid AreasCollege of AgronomyNorthwest A&F UniversityYanglingShaanxi712100China
| | - Qiang Xiao
- State Key Laboratory of Crop Stress Biology for Arid AreasCollege of AgronomyNorthwest A&F UniversityYanglingShaanxi712100China
| | - Jianchu Zhu
- State Key Laboratory of Crop Stress Biology for Arid AreasCollege of AgronomyNorthwest A&F UniversityYanglingShaanxi712100China
| | - Alice Y. Cheung
- Department of Biochemistry and Molecular BiologyUniversity of MassachusettsAmherstMA01003USA
| | - Li Yuan
- State Key Laboratory of Crop Stress Biology for Arid AreasCollege of HorticultureNorthwest A&F UniversityYanglingShaanxi712100China
| | - Elizabeth Vierling
- Department of Biochemistry and Molecular BiologyUniversity of MassachusettsAmherstMA01003USA
| | - Shengbao Xu
- State Key Laboratory of Crop Stress Biology for Arid AreasCollege of AgronomyNorthwest A&F UniversityYanglingShaanxi712100China
- Department of Biochemistry and Molecular BiologyUniversity of MassachusettsAmherstMA01003USA
- Ministry of Education Key Laboratory of Cell Activities and Stress AdaptationsSchool of Life SciencesLanzhou UniversityLanzhouGansu730000China
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14
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Waters ER, Vierling E. Plant small heat shock proteins - evolutionary and functional diversity. New Phytol 2020; 227:24-37. [PMID: 32297991 DOI: 10.1111/nph.16536] [Citation(s) in RCA: 101] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 02/21/2020] [Indexed: 05/22/2023]
Abstract
Small heat shock proteins (sHSPs) are an ubiquitous protein family found in archaea, bacteria and eukaryotes. In plants, as in other organisms, sHSPs are upregulated by stress and are proposed to act as molecular chaperones to protect other proteins from stress-induced damage. sHSPs share an 'α-crystallin domain' with a β-sandwich structure and a diverse N-terminal domain. Although sHSPs are 12-25 kDa polypeptides, most assemble into oligomers with ≥ 12 subunits. Plant sHSPs are particularly diverse and numerous; some species have as many as 40 sHSPs. In angiosperms this diversity comprises ≥ 11 sHSP classes encoding proteins targeted to the cytosol, nucleus, endoplasmic reticulum, chloroplasts, mitochondria and peroxisomes. The sHSPs underwent a lineage-specific gene expansion, diversifying early in land plant evolution, potentially in response to stress in the terrestrial environment, and expanded again in seed plants and again in angiosperms. Understanding the structure and evolution of plant sHSPs has progressed, and a model for their chaperone activity has been proposed. However, how the chaperone model applies to diverse sHSPs and what processes sHSPs protect are far from understood. As more plant genomes and transcriptomes become available, it will be possible to explore theories of the evolutionary pressures driving sHSP diversification.
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Affiliation(s)
- Elizabeth R Waters
- Biology Department, San Diego State University, San Diego, CA, 92182, USA
| | - Elizabeth Vierling
- Department of Biochemistry and Molecular Biology, University of Massachusetts Amherst, Amherst, MA, 01003, USA
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15
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McLoughlin F, Kim M, Marshall RS, Vierstra RD, Vierling E. HSP101 Interacts with the Proteasome and Promotes the Clearance of Ubiquitylated Protein Aggregates. Plant Physiol 2019; 180:1829-1847. [PMID: 31113833 PMCID: PMC6670096 DOI: 10.1104/pp.19.00263] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 05/09/2019] [Indexed: 05/18/2023]
Abstract
Stressful environments often lead to protein unfolding and the formation of cytotoxic aggregates that can compromise cell survival. The molecular chaperone heat shock protein (HSP) 101 is a protein disaggregase that co-operates with the small HSP (sHSP) and HSP70 chaperones to facilitate removal of such aggregates and is essential for surviving severe heat stress. To better define how HSP101 protects plants, we investigated the localization and targets of this chaperone in Arabidopsis (Arabidopsis thaliana). By following HSP101 tagged with GFP, we discovered that its intracellular distribution is highly dynamic and includes a robust, reversible sequestration into cytoplasmic foci that vary in number and size among cell types and are potentially enriched in aggregated proteins. Affinity isolation of HSP101 recovered multiple proteasome subunits, suggesting a functional interaction. Consistent with this, the GFP-tagged 26S proteasome regulatory particle non-ATPase (RPN) 1a transiently colocalized with HSP101 in cytoplasmic foci during recovery. In addition, analysis of aggregated (insoluble) proteins showed they are extensively ubiquitylated during heat stress, especially in plants deficient in HSP101 or class I sHSPs, implying that protein disaggregation is important for optimal proteasomal degradation. Many potential HSP101 clients, identified by mass spectrometry of insoluble proteins, overlapped with known stress granule constituents and sHSP-interacting proteins, confirming a role for HSP101 in stress granule function. Connections between HSP101, stress granules, proteasomes, and ubiquitylation imply that dynamic coordination between protein disaggregation and proteolysis is required to survive proteotoxic stress caused by protein aggregation at high temperatures.
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Affiliation(s)
- Fionn McLoughlin
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, Massachusetts 01009
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri 63130
| | - Minsoo Kim
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, Massachusetts 01009
| | - Richard S Marshall
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri 63130
| | - Richard D Vierstra
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri 63130
| | - Elizabeth Vierling
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, Massachusetts 01009
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16
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Carra S, Alberti S, Benesch JLP, Boelens W, Buchner J, Carver JA, Cecconi C, Ecroyd H, Gusev N, Hightower LE, Klevit RE, Lee HO, Liberek K, Lockwood B, Poletti A, Timmerman V, Toth ME, Vierling E, Wu T, Tanguay RM. Small heat shock proteins: multifaceted proteins with important implications for life. Cell Stress Chaperones 2019; 24:295-308. [PMID: 30758704 PMCID: PMC6439001 DOI: 10.1007/s12192-019-00979-z] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/01/2019] [Indexed: 12/21/2022] Open
Abstract
Small Heat Shock Proteins (sHSPs) evolved early in the history of life; they are present in archaea, bacteria, and eukaryota. sHSPs belong to the superfamily of molecular chaperones: they are components of the cellular protein quality control machinery and are thought to act as the first line of defense against conditions that endanger the cellular proteome. In plants, sHSPs protect cells against abiotic stresses, providing innovative targets for sustainable agricultural production. In humans, sHSPs (also known as HSPBs) are associated with the development of several neurological diseases. Thus, manipulation of sHSP expression may represent an attractive therapeutic strategy for disease treatment. Experimental evidence demonstrates that enhancing the chaperone function of sHSPs protects against age-related protein conformation diseases, which are characterized by protein aggregation. Moreover, sHSPs can promote longevity and healthy aging in vivo. In addition, sHSPs have been implicated in the prognosis of several types of cancer. Here, sHSP upregulation, by enhancing cellular health, could promote cancer development; on the other hand, their downregulation, by sensitizing cells to external stressors and chemotherapeutics, may have beneficial outcomes. The complexity and diversity of sHSP function and properties and the need to identify their specific clients, as well as their implication in human disease, have been discussed by many of the world's experts in the sHSP field during a dedicated workshop in Québec City, Canada, on 26-29 August 2018.
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Affiliation(s)
- Serena Carra
- Department of Biomedical, Metabolic and Neural Sciences, and Centre for Neuroscience and Nanotechnology, University of Modena and Reggio Emilia, via G. Campi 287, 41125, Modena, Italy.
| | - Simon Alberti
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307, Dresden, Germany
- Center for Molecular and Cellular Bioengineering (CMCB), Biotechnology Center (BIOTEC), Technische Universität Dresden, Tatzberg 47/49, 01307, Dresden, Germany
| | - Justin L P Benesch
- Department of Chemistry, Physical and Theoretical Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford, OX1 3TA, UK
| | - Wilbert Boelens
- Department of Biomolecular Chemistry, Institute of Molecules and Materials, Radboud University, NL-6500, Nijmegen, The Netherlands
| | - Johannes Buchner
- Center for Integrated Protein Science Munich (CIPSM) and Department Chemie, Technische Universität München, D-85748, Garching, Germany
| | - John A Carver
- Research School of Chemistry, The Australian National University, Acton, ACT, 2601, Australia
| | - Ciro Cecconi
- Department of Physics, Informatics and Mathematics, University of Modena and Reggio Emilia, 41125, Modena, Italy
- Center S3, CNR Institute Nanoscience, Via Campi 213/A, 41125, Modena, Italy
| | - Heath Ecroyd
- School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, Australia
- Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia
| | - Nikolai Gusev
- Department of Biochemistry, School of Biology, Moscow State University, Moscow, Russian Federation, 117234
| | - Lawrence E Hightower
- Department of Molecular and Cell Biology, University of Connecticut, 91 North Eagleville Road, Storrs, CT, 06269-3125, USA
| | - Rachel E Klevit
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Hyun O Lee
- Department of Biochemistry, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Krzysztof Liberek
- Department of Molecular and Cellular Biology, Intercollegiate Faculty of Biotechnology UG-MUG, University of Gdansk, Abrahama 58, 80-307, Gdansk, Poland
| | - Brent Lockwood
- Department of Biology, University of Vermont, Burlington, VT, 05405, USA
| | - Angelo Poletti
- Dipartimento di Scienze Farmacologiche e Biomolecolari (DiSFeB), Centro di Eccellenza sulle Malattie Neurodegenerative, Univrsità degli Studi di Milano, Milan, Italy
| | - Vincent Timmerman
- Peripheral Neuropathy Research Group, Department of Biomedical Sciences, University of Antwerp, 2610, Antwerp, Belgium
| | - Melinda E Toth
- Institute of Biochemistry, Biological Research Center, Hungarian Academy of Sciences, Szeged, Hungary
| | - Elizabeth Vierling
- Department of Biochemistry and Molecular Biology, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Tangchun Wu
- MOE Key Lab of Environment and Health, Tongji School of Public Health, Huazhong University of Science and Technology, 13 Hangkong Rd, Wuhan, 430030, Hubei, China
| | - Robert M Tanguay
- Laboratory of Cell and Developmental Genetics, IBIS, and Department of Molecular Biology, Medical Biochemistry and Pathology, Medical School, Université Laval, QC, Québec, G1V 0A6, Canada.
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17
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Wang X, Hou L, Lu Y, Wu B, Gong X, Liu M, Wang J, Sun Q, Vierling E, Xu S. Metabolic adaptation of wheat grain contributes to a stable filling rate under heat stress. J Exp Bot 2018; 69:5531-5545. [PMID: 30476278 PMCID: PMC6255704 DOI: 10.1093/jxb/ery303] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Accepted: 08/11/2018] [Indexed: 05/23/2023]
Abstract
Wheat (Triticum aestivum) is particularly vulnerable to heat stress during the grain filling stage, and this can adversely affect the final yield. However, the underlying physiological and molecular mechanisms are largely unknown. In this study, the effects of heat stress on grain filling were investigated using wheat varieties with different levels of thermotolerance. Decreased grain weights and filling durations, increased protein contents, and stable filling rates across diverse varieties under different heat regimes suggested a general mechanism for heat adaptation. Proteomic analysis identified 309 heat-responsive proteins (HRPs), and revealed a general decrease in protein synthesis components and metabolic proteins, but a significant increase in stress-response proteins and storage proteins. Metabolomic analysis identified 98 metabolites specifically changed by heat stress, and suggested a global decrease in the content of carbohydrate metabolites, an increased content of amino acids, and stable levels of starch synthesis precursors. The energy-consuming HRPs suggested that less energy was channelled into metabolism and protein synthesis, whereas more energy was allocated to the stress response under elevated heat conditions. Collectively, the data demonstrated a widely distributed mechanism for heat adaptation of metabolism, in which the assimilation and energy required for metabolism and protein synthesis are reallocated to heat protection and deposition of reserves, resulting in increased storage protein accumulation and a stable filling rate.
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Affiliation(s)
- Xiaoming Wang
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Agronomy, Northwest A&F University, Yangling, Shaanxi, China
| | - Lijiang Hou
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Agronomy, Northwest A&F University, Yangling, Shaanxi, China
| | - Yunze Lu
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Agronomy, Northwest A&F University, Yangling, Shaanxi, China
| | - Bingjin Wu
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Agronomy, Northwest A&F University, Yangling, Shaanxi, China
| | - Xue Gong
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Agronomy, Northwest A&F University, Yangling, Shaanxi, China
| | - Manshuang Liu
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Agronomy, Northwest A&F University, Yangling, Shaanxi, China
| | - Jun Wang
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Agronomy, Northwest A&F University, Yangling, Shaanxi, China
| | - Qixin Sun
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Agronomy, Northwest A&F University, Yangling, Shaanxi, China
- Department of Plant Genetics & Breeding, China Agricultural University, Haidian District, Beijing, China
| | - Elizabeth Vierling
- Department of Biochemistry & Molecular Biology, University of Massachusetts, Amherst, MA, USA
| | - Shengbao Xu
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Agronomy, Northwest A&F University, Yangling, Shaanxi, China
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18
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Santhanagopalan I, Degiacomi MT, Shepherd DA, Hochberg GKA, Benesch JLP, Vierling E. It takes a dimer to tango: Oligomeric small heat shock proteins dissociate to capture substrate. J Biol Chem 2018; 293:19511-19521. [PMID: 30348902 DOI: 10.1074/jbc.ra118.005421] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Revised: 10/12/2018] [Indexed: 12/23/2022] Open
Abstract
Small heat-shock proteins (sHsps) are ubiquitous molecular chaperones, and sHsp mutations or altered expression are linked to multiple human disease states. sHsp monomers assemble into large oligomers with dimeric substructure, and the dynamics of sHsp oligomers has led to major questions about the form that captures substrate, a critical aspect of their mechanism of action. We show here that substructural dimers of two plant dodecameric sHsps, Ta16.9 and homologous Ps18.1, are functional units in the initial encounter with unfolding substrate. We introduced inter-polypeptide disulfide bonds at the two dodecameric interfaces, dimeric and nondimeric, to restrict how their assemblies can dissociate. When disulfide-bonded at the nondimeric interface, mutants of Ta16.9 and Ps18.1 (TaCT-ACD and PsCT-ACD) were inactive but, when reduced, had WT-like chaperone activity, demonstrating that dissociation at nondimeric interfaces is essential for sHsp activity. Moreover, the size of the TaCT-ACD and PsCT-ACD covalent unit defined a new tetrahedral geometry for these sHsps, different from that observed in the Ta16.9 X-ray structure. Importantly, oxidized Tadimer (disulfide bonded at the dimeric interface) exhibited greatly enhanced ability to protect substrate, indicating that strengthening the dimeric interface increases chaperone efficiency. Temperature-induced size and secondary structure changes revealed that folded sHsp dimers interact with substrate and that dimer stability affects chaperone efficiency. These results yield a model in which sHsp dimers capture substrate before assembly into larger, heterogeneous sHsp-substrate complexes for substrate refolding or degradation, and suggest that tuning the strength of the dimer interface can be used to engineer sHsp chaperone efficiency.
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Affiliation(s)
- Indu Santhanagopalan
- From the Department of Biochemistry and Molecular Biology, University of Massachusetts Amherst, Amherst, Massachusetts 01003
| | - Matteo T Degiacomi
- Department of Chemistry, Physical & Theoretical Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford, OX1 3TA, United Kingdom, and.,Department of Chemistry, Durham University, South Road, Durham, DH1 3LE, United Kingdom
| | - Dale A Shepherd
- Department of Chemistry, Physical & Theoretical Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford, OX1 3TA, United Kingdom, and
| | - Georg K A Hochberg
- Department of Chemistry, Physical & Theoretical Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford, OX1 3TA, United Kingdom, and
| | - Justin L P Benesch
- Department of Chemistry, Physical & Theoretical Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford, OX1 3TA, United Kingdom, and
| | - Elizabeth Vierling
- From the Department of Biochemistry and Molecular Biology, University of Massachusetts Amherst, Amherst, Massachusetts 01003,
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19
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Marklund EG, Zhang Y, Basha E, Benesch JLP, Vierling E. Structural and functional aspects of the interaction partners of the small heat-shock protein in Synechocystis. Cell Stress Chaperones 2018; 23:723-732. [PMID: 29476342 PMCID: PMC6045555 DOI: 10.1007/s12192-018-0884-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2017] [Revised: 01/09/2018] [Accepted: 02/01/2018] [Indexed: 01/28/2023] Open
Abstract
The canonical function of small heat-shock proteins (sHSPs) is to interact with proteins destabilized under conditions of cellular stress. While the breadth of interactions made by many sHSPs is well-known, there is currently little knowledge about what structural features of the interactors form the basis for their recognition. Here, we have identified 83 in vivo interactors of the sole sHSP in the cyanobacterium Synechocystis sp. PCC 6803, HSP16.6, reflective of stable associations with soluble proteins made under heat-shock conditions. By performing bioinformatic analyses on these interactors, we identify primary and secondary structural elements that are enriched relative to expectations from the cyanobacterial genome. In addition, by examining the Synechocystis interactors and comparing them with those identified to bind sHSPs in other prokaryotes, we show that sHSPs associate with specific proteins and biological processes. Our data are therefore consistent with a picture of sHSPs being broadly specific molecular chaperones that act to protect multiple cellular pathways.
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Affiliation(s)
- Erik G Marklund
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory, University of Oxford, Oxford, OX1 3QZ, UK
- Department of Chemistry - BMC, Uppsala University, Box 576, Uppsala, 75123, Sweden
| | - Yichen Zhang
- Department of Biochemistry & Molecular Biology, University of Massachusetts, Amherst, MA, 01003, USA
- Alorica, Inc., Irvine, CA, USA
| | - Eman Basha
- Department of Biochemistry & Molecular Biology, University of Massachusetts, Amherst, MA, 01003, USA
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ, 85721, USA
| | - Justin L P Benesch
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory, University of Oxford, Oxford, OX1 3QZ, UK.
| | - Elizabeth Vierling
- Department of Biochemistry & Molecular Biology, University of Massachusetts, Amherst, MA, 01003, USA.
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20
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Marklund EG, Zhang Y, Basha E, Benesch JLP, Vierling E. Correction to: Structural and functional aspects of the interaction partners of the small heat-shock protein in Synechocystis. Cell Stress Chaperones 2018; 23:733. [PMID: 29721819 PMCID: PMC6045545 DOI: 10.1007/s12192-018-0901-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022] Open
Abstract
Table 1 in the original publication has been corrected.
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Affiliation(s)
- Erik G Marklund
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory, University of Oxford, Oxford, OX1 3QZ, UK
- Department of Chemistry - BMC, Uppsala University, Box 576, Uppsala, 75123, Sweden
| | - Yichen Zhang
- Department of Biochemistry & Molecular Biology, University of Massachusetts, Amherst, MA, 01003, USA
- Alorica, Inc., Irvine, CA, USA
| | - Eman Basha
- Department of Biochemistry & Molecular Biology, University of Massachusetts, Amherst, MA, 01003, USA
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ, 85721, USA
| | - Justin L P Benesch
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory, University of Oxford, Oxford, OX1 3QZ, UK.
| | - Elizabeth Vierling
- Department of Biochemistry & Molecular Biology, University of Massachusetts, Amherst, MA, 01003, USA.
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21
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Hochberg GKA, Shepherd DA, Marklund EG, Santhanagoplan I, Degiacomi MT, Laganowsky A, Allison TM, Basha E, Marty MT, Galpin MR, Struwe WB, Baldwin AJ, Vierling E, Benesch JLP. Structural principles that enable oligomeric small heat-shock protein paralogs to evolve distinct functions. Science 2018; 359:930-935. [PMID: 29472485 PMCID: PMC6587588 DOI: 10.1126/science.aam7229] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2017] [Revised: 09/25/2017] [Accepted: 01/08/2018] [Indexed: 12/26/2022]
Abstract
Oligomeric proteins assemble with exceptional selectivity, even in the presence of closely related proteins, to perform their cellular roles. We show that most proteins related by gene duplication of an oligomeric ancestor have evolved to avoid hetero-oligomerization and that this correlates with their acquisition of distinct functions. We report how coassembly is avoided by two oligomeric small heat-shock protein paralogs. A hierarchy of assembly, involving intermediates that are populated only fleetingly at equilibrium, ensures selective oligomerization. Conformational flexibility at noninterfacial regions in the monomers prevents coassembly, allowing interfaces to remain largely conserved. Homomeric oligomers must overcome the entropic benefit of coassembly and, accordingly, homomeric paralogs comprise fewer subunits than homomers that have no paralogs.
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Affiliation(s)
- Georg K A Hochberg
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3QZ, UK
| | - Dale A Shepherd
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3QZ, UK
| | - Erik G Marklund
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3QZ, UK
| | - Indu Santhanagoplan
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, MA 01003, USA
| | - Matteo T Degiacomi
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3QZ, UK
| | - Arthur Laganowsky
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3QZ, UK
| | - Timothy M Allison
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3QZ, UK
| | - Eman Basha
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, MA 01003, USA
| | - Michael T Marty
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3QZ, UK
| | - Martin R Galpin
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3QZ, UK
| | - Weston B Struwe
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3QZ, UK
| | - Andrew J Baldwin
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3QZ, UK
| | - Elizabeth Vierling
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, MA 01003, USA
| | - Justin L P Benesch
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3QZ, UK.
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22
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Zhang L, Liu X, Gaikwad K, Kou X, Wang F, Tian X, Xin M, Ni Z, Sun Q, Peng H, Vierling E. Mutations in eIF5B Confer Thermosensitive and Pleiotropic Phenotypes via Translation Defects in Arabidopsis thaliana. Plant Cell 2017; 29:1952-1969. [PMID: 28808135 PMCID: PMC5590492 DOI: 10.1105/tpc.16.00808] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Revised: 06/16/2017] [Accepted: 08/09/2017] [Indexed: 05/19/2023]
Abstract
The conserved eukaryotic translation initiation factor 5B, eIF5B, is a GTPase that acts late in translation initiation. We found that an Arabidopsis thaliana mutant sensitive to hot temperatures 3 (hot3-1), which behaves as the wild type in the absence of stress but is unable to acclimate to high temperature, carries a missense mutation in the eIF5B1 gene (At1g76810), producing a temperature sensitive protein. A more severe, T-DNA insertion allele (hot3-2) causes pleiotropic developmental phenotypes. Surprisingly, Arabidopsis has three other eIF5B genes that do not substitute for eIF5B1; two of these appear to be in the process of pseudogenization. Polysome profiling and RNA-seq analysis of hot3-1 plants show delayed recovery of polysomes after heat stress and reduced translational efficiency (TE) of a subset of stress protective proteins, demonstrating the critical role of translational control early in heat acclimation. Plants carrying the severe hot3-2 allele show decreased TE of auxin-regulated, ribosome-related, and electron transport genes, even under optimal growth conditions. The hot3-2 data suggest that disrupting specific eIF5B interactions on the ribosome can, directly or indirectly, differentially affect translation. Thus, modulating eIF5B interactions could be another mechanism of gene-specific translational control.
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Affiliation(s)
- Liyuan Zhang
- State Key Laboratory for Agrobiotechnology and Key Laboratory of Crop Heterosis and Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, Department of Plant Genetics and Breeding, China Agricultural University, Beijing 100193, P.R. China
| | - Xinye Liu
- State Key Laboratory for Agrobiotechnology and Key Laboratory of Crop Heterosis and Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, Department of Plant Genetics and Breeding, China Agricultural University, Beijing 100193, P.R. China
| | - Kishor Gaikwad
- National Research Centre on Plant Biotechnology, New Delhi 110012, India
| | - Xiaoxia Kou
- State Key Laboratory for Agrobiotechnology and Key Laboratory of Crop Heterosis and Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, Department of Plant Genetics and Breeding, China Agricultural University, Beijing 100193, P.R. China
| | - Fei Wang
- State Key Laboratory for Agrobiotechnology and Key Laboratory of Crop Heterosis and Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, Department of Plant Genetics and Breeding, China Agricultural University, Beijing 100193, P.R. China
| | - Xuejun Tian
- State Key Laboratory for Agrobiotechnology and Key Laboratory of Crop Heterosis and Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, Department of Plant Genetics and Breeding, China Agricultural University, Beijing 100193, P.R. China
| | - Mingming Xin
- State Key Laboratory for Agrobiotechnology and Key Laboratory of Crop Heterosis and Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, Department of Plant Genetics and Breeding, China Agricultural University, Beijing 100193, P.R. China
| | - Zhongfu Ni
- State Key Laboratory for Agrobiotechnology and Key Laboratory of Crop Heterosis and Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, Department of Plant Genetics and Breeding, China Agricultural University, Beijing 100193, P.R. China
| | - Qixin Sun
- State Key Laboratory for Agrobiotechnology and Key Laboratory of Crop Heterosis and Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, Department of Plant Genetics and Breeding, China Agricultural University, Beijing 100193, P.R. China
| | - Huiru Peng
- State Key Laboratory for Agrobiotechnology and Key Laboratory of Crop Heterosis and Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, Department of Plant Genetics and Breeding, China Agricultural University, Beijing 100193, P.R. China
| | - Elizabeth Vierling
- University of Massachusetts Amherst, Biochemistry and Molecular Biology, Amherst, Massachusetts 01003
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23
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Kim M, McLoughlin F, Basha E, Vierling E. Assessing Plant Tolerance to Acute Heat Stress. Bio Protoc 2017; 7:e2405. [PMID: 34541136 DOI: 10.21769/bioprotoc.2405] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 05/22/2017] [Accepted: 06/26/2017] [Indexed: 11/02/2022] Open
Abstract
It is well-established that plants are able to acclimate to temperatures above or below the optimal temperature for their growth. Here, we provide protocols for assays that can be used quantitatively or qualitatively to assess the relative ability of plants to acquire tolerance to high temperature stress. The hypocotyl elongation assay described was developed to screen for mutants defective in the acquisition of tolerance to extreme temperature stress, and other assays were developed to further characterize mutant and transgenic plants for heat tolerance of other processes or at other growth stages. Although the protocols provide details for application to Arabidopsis thaliana, the same basic methods can be adopted to assay heat tolerance in other plant species.
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Affiliation(s)
- Minsoo Kim
- Department of Biochemistry & Molecular Biology, University of Massachusetts Amherst, Amherst, MA, USA
| | - Fionn McLoughlin
- Department of Biochemistry & Molecular Biology, University of Massachusetts Amherst, Amherst, MA, USA
| | - Eman Basha
- Department of Botany, Tanta University, Tanta, Egypt
| | - Elizabeth Vierling
- Department of Biochemistry & Molecular Biology, University of Massachusetts Amherst, Amherst, MA, USA
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Carra S, Alberti S, Arrigo PA, Benesch JL, Benjamin IJ, Boelens W, Bartelt-Kirbach B, Brundel BJJM, Buchner J, Bukau B, Carver JA, Ecroyd H, Emanuelsson C, Finet S, Golenhofen N, Goloubinoff P, Gusev N, Haslbeck M, Hightower LE, Kampinga HH, Klevit RE, Liberek K, Mchaourab HS, McMenimen KA, Poletti A, Quinlan R, Strelkov SV, Toth ME, Vierling E, Tanguay RM. The growing world of small heat shock proteins: from structure to functions. Cell Stress Chaperones 2017; 22:601-611. [PMID: 28364346 PMCID: PMC5465036 DOI: 10.1007/s12192-017-0787-8] [Citation(s) in RCA: 118] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/15/2017] [Indexed: 12/21/2022] Open
Abstract
Small heat shock proteins (sHSPs) are present in all kingdoms of life and play fundamental roles in cell biology. sHSPs are key components of the cellular protein quality control system, acting as the first line of defense against conditions that affect protein homeostasis and proteome stability, from bacteria to plants to humans. sHSPs have the ability to bind to a large subset of substrates and to maintain them in a state competent for refolding or clearance with the assistance of the HSP70 machinery. sHSPs participate in a number of biological processes, from the cell cycle, to cell differentiation, from adaptation to stressful conditions, to apoptosis, and, even, to the transformation of a cell into a malignant state. As a consequence, sHSP malfunction has been implicated in abnormal placental development and preterm deliveries, in the prognosis of several types of cancer, and in the development of neurological diseases. Moreover, mutations in the genes encoding several mammalian sHSPs result in neurological, muscular, or cardiac age-related diseases in humans. Loss of protein homeostasis due to protein aggregation is typical of many age-related neurodegenerative and neuromuscular diseases. In light of the role of sHSPs in the clearance of un/misfolded aggregation-prone substrates, pharmacological modulation of sHSP expression or function and rescue of defective sHSPs represent possible routes to alleviate or cure protein conformation diseases. Here, we report the latest news and views on sHSPs discussed by many of the world's experts in the sHSP field during a dedicated workshop organized in Italy (Bertinoro, CEUB, October 12-15, 2016).
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Affiliation(s)
- Serena Carra
- Department of Biomedical, Metabolic and Neural Sciences, and Centre for Neuroscience and Neurotechnology, University of Modena and Reggio Emilia, via G. Campi 287, 41125 Modena, Italy
| | - Simon Alberti
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Patrick A. Arrigo
- Université de Lyon, 69622 Lyon, France
- CNRS, UMR 5310, INSERM U1217, Institut NeuroMyoGène, Université Lyon 1, 69100 Villeurbanne, France
| | | | - Ivor J. Benjamin
- Department of Biochemistry, University of Utah, Salt Lake City, UT 84112-5650 USA
| | - Wilbert Boelens
- Biomolecular Chemistry, 284, Radboud University, PO Box 9101, 6500 HB Nijmegen, The Netherlands
| | | | - Bianca J. J. M. Brundel
- Department of Clinical Pharmacy and Pharmacology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
- Department of Physiology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands
| | | | - Bernd Bukau
- Center for Molecular Biology of the University of Heidelberg (ZMBH), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, 69120 Heidelberg, Germany
- German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - John A. Carver
- The Research School of Chemistry, The Australian National University, Acton, ACT 2601 Australia
| | - Heath Ecroyd
- Illawara Health and Medical Research Institute, School of Biological Sciences, University of Wollongong, Wollongong, NSW 2522 Australia
| | - Cecilia Emanuelsson
- Department of Biochemistry and Structural Biology, Center for Molecular Protein Science, Lund University, 221 00 Lund, Sweden
| | - Stephanie Finet
- IMPMC UMR7590, CNRS, UPMC Paris 6, 4 place Jussieu, Paris, France
| | - Nikola Golenhofen
- Institute of Anatomy and Cell Biology, University of Ulm, 89081 Ulm, Germany
| | - Pierre Goloubinoff
- Department of Plant Molecular Biology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Nikolai Gusev
- Department of Biochemistry, School of Biology, Moscow State University, Moscow, 119991 Russia
| | | | - Lawrence E. Hightower
- Department of Molecular & Cell Biology, University of Connecticut, 91 North Eagleville Road, Storrs, CT 06269-3125 USA
| | - Harm H. Kampinga
- Department of Cell Biology, University Medical Center Groningen, University of Groningen, 9713 GZ Groningen, The Netherlands
| | - Rachel E. Klevit
- Department of Biochemistry, University of Washington, Seattle, WA 98195 USA
| | - Krzysztof Liberek
- Department of Molecular and Cellular Biology, Intercollegiate Faculty of Biotechnology, University of Gdańsk and the Medical University of Gdańsk, Gdańsk, Poland
| | - Hassane S. Mchaourab
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232 USA
| | - Kathryn A. McMenimen
- Departments of Pathology, Biological Chemistry, and Medicinal Chemistry and the Life Sciences Institute, University of Michigan, Ann Arbor, MI USA
| | - Angelo Poletti
- Dipartimento di Scienze Farmacologiche e Biomolecolari (DiSFeB), Centro di Eccellenza sulle Malattie Neurodegenerative, Università degli Studi di Milano, Milan, Italy
| | - Roy Quinlan
- Department of Biosciences and the Biophysical Sciences Institute, University of Durham, Durham, UK
| | - Sergei V. Strelkov
- Laboratory for Biocrystallography, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium
| | - Melinda E. Toth
- Laboratory of Animal Genetics and Molecular Neurobiology, Institute of Biochemistry, Biological Research Centre, Szeged, Hungary
| | - Elizabeth Vierling
- Biochemistry and Molecular Biology, University of Massachusetts, Amherst, MA 01003 USA
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721 USA
| | - Robert M. Tanguay
- Laboratory of Cell & Developmental Genetics, IBIS, and Department of Molecular Biology, Medical Biochemistry and Pathology, Medical School, Université Laval, Québec (Qc), G1V 0A6 Canada
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McLoughlin F, Basha E, Fowler ME, Kim M, Bordowitz J, Katiyar-Agarwal S, Vierling E. Class I and II Small Heat Shock Proteins Together with HSP101 Protect Protein Translation Factors during Heat Stress. Plant Physiol 2016; 172:1221-1236. [PMID: 27474115 PMCID: PMC5047077 DOI: 10.1104/pp.16.00536] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2016] [Accepted: 07/25/2016] [Indexed: 05/23/2023]
Abstract
The ubiquitous small heat shock proteins (sHSPs) are well documented to act in vitro as molecular chaperones to prevent the irreversible aggregation of heat-sensitive proteins. However, the in vivo activities of sHSPs remain unclear. To investigate the two most abundant classes of plant cytosolic sHSPs (class I [CI] and class II [CII]), RNA interference (RNAi) and overexpression lines were created in Arabidopsis (Arabidopsis thaliana) and shown to have reduced and enhanced tolerance, respectively, to extreme heat stress. Affinity purification of CI and CII sHSPs from heat-stressed seedlings recovered eukaryotic translation elongation factor (eEF) 1B (α-, β-, and γ-subunits) and eukaryotic translation initiation factor 4A (three isoforms), although the association with CI sHSPs was stronger and additional proteins involved in translation were recovered with CI sHSPs. eEF1B subunits became partially insoluble during heat stress and, in the CI and CII RNAi lines, showed reduced recovery to the soluble cell fraction after heat stress, which was also dependent on HSP101. Furthermore, after heat stress, CI sHSPs showed increased retention in the insoluble fraction in the CII RNAi line and vice versa. Immunolocalization revealed that both CI and CII sHSPs were present in cytosolic foci, some of which colocalized with HSP101 and with eEF1Bγ and eEF1Bβ. Thus, CI and CII sHSPs have both unique and overlapping functions and act either directly or indirectly to protect specific translation factors in cytosolic stress granules.
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Affiliation(s)
- Fionn McLoughlin
- Biochemistry and Molecular Biology, University of Massachusetts, Amherst, Massachusetts 01003 (F.M., M.E.F., M.K., E.V.);Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721 (E.B., M.K., J.B., S.K.-A.); andDepartment of Botany, Tanta University, Tanta 31527, Egypt (E.B.)
| | - Eman Basha
- Biochemistry and Molecular Biology, University of Massachusetts, Amherst, Massachusetts 01003 (F.M., M.E.F., M.K., E.V.);Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721 (E.B., M.K., J.B., S.K.-A.); andDepartment of Botany, Tanta University, Tanta 31527, Egypt (E.B.)
| | - Mary E Fowler
- Biochemistry and Molecular Biology, University of Massachusetts, Amherst, Massachusetts 01003 (F.M., M.E.F., M.K., E.V.);Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721 (E.B., M.K., J.B., S.K.-A.); andDepartment of Botany, Tanta University, Tanta 31527, Egypt (E.B.)
| | - Minsoo Kim
- Biochemistry and Molecular Biology, University of Massachusetts, Amherst, Massachusetts 01003 (F.M., M.E.F., M.K., E.V.);Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721 (E.B., M.K., J.B., S.K.-A.); andDepartment of Botany, Tanta University, Tanta 31527, Egypt (E.B.)
| | - Juliana Bordowitz
- Biochemistry and Molecular Biology, University of Massachusetts, Amherst, Massachusetts 01003 (F.M., M.E.F., M.K., E.V.);Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721 (E.B., M.K., J.B., S.K.-A.); andDepartment of Botany, Tanta University, Tanta 31527, Egypt (E.B.)
| | - Surekha Katiyar-Agarwal
- Biochemistry and Molecular Biology, University of Massachusetts, Amherst, Massachusetts 01003 (F.M., M.E.F., M.K., E.V.);Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721 (E.B., M.K., J.B., S.K.-A.); andDepartment of Botany, Tanta University, Tanta 31527, Egypt (E.B.)
| | - Elizabeth Vierling
- Biochemistry and Molecular Biology, University of Massachusetts, Amherst, Massachusetts 01003 (F.M., M.E.F., M.K., E.V.);Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721 (E.B., M.K., J.B., S.K.-A.); andDepartment of Botany, Tanta University, Tanta 31527, Egypt (E.B.)
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26
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Guerra D, Ballard K, Truebridge I, Vierling E. S-Nitrosation of Conserved Cysteines Modulates Activity and Stability of S-Nitrosoglutathione Reductase (GSNOR). Biochemistry 2016; 55:2452-64. [PMID: 27064847 DOI: 10.1021/acs.biochem.5b01373] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The free radical nitric oxide (NO(•)) regulates diverse physiological processes from vasodilation in humans to gas exchange in plants. S-Nitrosoglutathione (GSNO) is considered a principal nitroso reservoir due to its chemical stability. GSNO accumulation is attenuated by GSNO reductase (GSNOR), a cysteine-rich cytosolic enzyme. Regulation of protein nitrosation is not well understood since NO(•)-dependent events proceed without discernible changes in GSNOR expression. Because GSNORs contain evolutionarily conserved cysteines that could serve as nitrosation sites, we examined the effects of treating plant (Arabidopsis thaliana), mammalian (human), and yeast (Saccharomyces cerevisiae) GSNORs with nitrosating agents in vitro. Enzyme activity was sensitive to nitroso donors, whereas the reducing agent dithiothreitol (DTT) restored activity, suggesting that catalytic impairment was due to S-nitrosation. Protein nitrosation was confirmed by mass spectrometry, by which mono-, di-, and trinitrosation were observed, and these signals were sensitive to DTT. GSNOR mutants in specific non-zinc-coordinating cysteines were less sensitive to catalytic inhibition by nitroso donors and exhibited reduced nitrosation signals by mass spectrometry. Nitrosation also coincided with decreased tryptophan fluorescence, increased thermal aggregation propensity, and increased polydispersity-properties reflected by differential solvent accessibility of amino acids important for dimerization and the shape of the substrate and coenzyme binding pockets as assessed by hydrogen-deuterium exchange mass spectrometry. Collectively, these data suggest a mechanism for NO(•) signal transduction in which GSNOR nitrosation and inhibition transiently permit GSNO accumulation.
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Affiliation(s)
- Damian Guerra
- Department of Biochemistry and Molecular Biology, University of Massachusetts , 240 Thatcher Road, Amherst, Massachusetts 01003, United States
| | - Keith Ballard
- Department of Biochemistry and Molecular Biology, University of Massachusetts , 240 Thatcher Road, Amherst, Massachusetts 01003, United States
| | - Ian Truebridge
- Department of Biochemistry and Molecular Biology, University of Massachusetts , 240 Thatcher Road, Amherst, Massachusetts 01003, United States
| | - Elizabeth Vierling
- Department of Biochemistry and Molecular Biology, University of Massachusetts , 240 Thatcher Road, Amherst, Massachusetts 01003, United States
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27
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Haslbeck M, Vierling E. A first line of stress defense: small heat shock proteins and their function in protein homeostasis. J Mol Biol 2015; 427:1537-48. [PMID: 25681016 DOI: 10.1016/j.jmb.2015.02.002] [Citation(s) in RCA: 373] [Impact Index Per Article: 41.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2015] [Revised: 02/03/2015] [Accepted: 02/04/2015] [Indexed: 10/24/2022]
Abstract
Small heat shock proteins (sHsps) are virtually ubiquitous molecular chaperones that can prevent the irreversible aggregation of denaturing proteins. sHsps complex with a variety of non-native proteins in an ATP-independent manner and, in the context of the stress response, form a first line of defense against protein aggregation in order to maintain protein homeostasis. In vertebrates, they act to maintain the clarity of the eye lens, and in humans, sHsp mutations are linked to myopathies and neuropathies. Although found in all domains of life, sHsps are quite diverse and have evolved independently in metazoans, plants and fungi. sHsp monomers range in size from approximately 12 to 42kDa and are defined by a conserved β-sandwich α-crystallin domain, flanked by variable N- and C-terminal sequences. Most sHsps form large oligomeric ensembles with a broad distribution of different, sphere- or barrel-like oligomers, with the size and structure of the oligomers dictated by features of the N- and C-termini. The activity of sHsps is regulated by mechanisms that change the equilibrium distribution in tertiary features and/or quaternary structure of the sHsp ensembles. Cooperation and/or co-assembly between different sHsps in the same cellular compartment add an underexplored level of complexity to sHsp structure and function.
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Affiliation(s)
- Martin Haslbeck
- Department Chemie, Technische Universität München, Lichtenbergstrasse 4, 85 748 Garching, Germany.
| | - Elizabeth Vierling
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Life Science Laboratories, N329 240 Thatcher Road, Amherst, MA 01003-9364, USA.
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Patel S, Vierling E, Tama F. Replica exchange molecular dynamics simulations provide insight into substrate recognition by small heat shock proteins. Biophys J 2014; 106:2644-55. [PMID: 24940782 PMCID: PMC4070073 DOI: 10.1016/j.bpj.2014.04.048] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Revised: 04/20/2014] [Accepted: 04/23/2014] [Indexed: 11/18/2022] Open
Abstract
The small heat shock proteins (sHSPs) are a virtually ubiquitous and diverse group of molecular chaperones that can bind and protect unfolding proteins from irreversible aggregation. It has been suggested that intrinsic disorder of the N-terminal arm (NTA) of sHSPs is important for substrate recognition. To investigate conformations of the NTA that could recognize substrates we performed replica exchange molecular dynamics simulations. Behavior at normal and stress temperatures of the dimeric building blocks of dodecameric HSPs from wheat (Ta16.9) and pea (Ps18.1) were compared because they display high sequence similarity, but Ps18.1 is more efficient in binding specific substrates. In our simulations, the NTAs of the dimer are flexible and dynamic; however, rather than exhibiting highly extended conformations they retain considerable α-helical character and contacts with the conserved α-crystallin domain (ACD). Network analysis and clustering methods reveal that there are two major conformational forms designated either "open" or "closed" based on the relative position of the two NTAs and their hydrophobic solvent accessible surface area. The equilibrium constant for the closed to open transition is significantly different for Ta16.9 and Ps18.1, with the latter showing more open conformations at elevated temperature correlated with its more effective chaperone activity. In addition, the Ps18.1 NTAs have more hydrophobic solvent accessible surface than those of Ta16.9. NTA hydrophobic patches are comparable in size to the area buried in many protein-protein interactions, which would enable sHSPs to bind early unfolding intermediates. Reduced interactions of the Ps18.1 NTAs with each other and with the ACD contribute to the differences in dynamics and hydrophobic surface area of the two sHSPs. These data support a major role for the conformational equilibrium of the NTA in substrate binding and indicate features of the NTA that contribute to sHSP chaperone efficiency.
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Affiliation(s)
- Sunita Patel
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona
| | - Elizabeth Vierling
- Department of Biochemistry & Molecular Biology, University of Massachusetts, Amherst, Massachusetts
| | - Florence Tama
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona; RIKEN, Advanced Institute for Computational Sciences, 7-1-26, Minatojima-minami-machi, Chuo-ku, Kobe, Hyogo, 650-0047, Japan.
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Basha E, Jones C, Blackwell AE, Cheng G, Waters ER, Samsel KA, Siddique M, Pett V, Wysocki V, Vierling E. An unusual dimeric small heat shock protein provides insight into the mechanism of this class of chaperones. J Mol Biol 2013; 425:1683-96. [PMID: 23416558 DOI: 10.1016/j.jmb.2013.02.011] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2012] [Revised: 02/07/2013] [Accepted: 02/08/2013] [Indexed: 12/11/2022]
Abstract
Small heat shock proteins (sHSPs) are virtually ubiquitous stress proteins that are also found in many normal tissues and accumulate in diseases of protein folding. They generally act as ATP-independent chaperones to bind and stabilize denaturing proteins that can be later reactivated by ATP-dependent Hsp70/DnaK, but the mechanism of substrate capture by sHSPs remains poorly understood. A majority of sHSPs form large oligomers, a property that has been linked to their effective chaperone action. We describe AtHsp18.5 from Arabidopsis thaliana, demonstrating that it is dimeric and exhibits robust chaperone activity, which adds support to the model that suboligomeric sHSP forms are a substrate binding species. Notably, like oligomeric sHSPs, when bound to substrate, AtHsp18.5 assembles into large complexes, indicating that reformation of sHSP oligomeric contacts is not required for assembly of sHSP-substrate complexes. Monomers of AtHsp18.5 freely exchange between dimers but fail to coassemble in vitro with dodecameric plant cytosolic sHSPs, suggesting that AtHsp18.5 does not interact by coassembly with these other sHSPs in vivo. Data from controlled proteolysis and hydrogen-deuterium exchange coupled with mass spectrometry show that the N- and C-termini of AtHsp18.5 are highly accessible and lack stable secondary structure, most likely a requirement for substrate interaction. Chaperone activity of a series of AtHsp18.5 truncation mutants confirms that the N-terminal arm is required for substrate protection and that different substrates interact differently with the N-terminal arm. In total, these data imply that the core α-crystallin domain of the sHSPs is a platform for flexible arms that capture substrates to maintain their solubility.
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Affiliation(s)
- Eman Basha
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721, USA
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30
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Xu S, Guerra D, Lee U, Vierling E. S-nitrosoglutathione reductases are low-copy number, cysteine-rich proteins in plants that control multiple developmental and defense responses in Arabidopsis. Front Plant Sci 2013; 4:430. [PMID: 24204370 PMCID: PMC3817919 DOI: 10.3389/fpls.2013.00430] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Accepted: 10/10/2013] [Indexed: 05/03/2023]
Abstract
S-nitrosoglutathione reductase (GSNOR) is believed to modulate effects of reactive oxygen and nitrogen species through catabolism of S-nitrosoglutathione (GSNO). We combined bioinformatics of plant GSNOR genes, localization of GSNOR in Arabidopsis thaliana, and microarray analysis of a GSNOR null mutant to gain insights into the function and regulation of this critical enzyme in nitric oxide (NO) homeostasis. GSNOR-encoding genes are known to have high homology across diverse eukaryotic taxa, but contributions of specific conserved residues have not been assessed. With bioinformatics and structural modeling, we show that plant GSNORs likely localize to the cytosol, contain conserved, solvent-accessible cysteines, and tend to be encoded by a single gene. Arabidopsis thaliana homozygous for GSNOR loss-of-function alleles exhibited defects in stem and trichome branching, and complementation with Green fluorescent protein (GFP) -tagged GSNOR under control of the native promoter quantitatively rescued these phenotypes. GSNOR-GFP showed fluorescence throughout Arabidopsis seedlings, consistent with ubiquitous expression of the protein, but with especially high fluorescence in the root tip, apical meristem, and flowers. At the cellular level we observed cytosolic and nuclear fluorescence, with exclusion from the nucleolus. Microarray analysis identified 99 up- and 170 down-regulated genes (≥2-fold; p ≤ 0.01) in a GSNOR null mutant compared to wild type. Six members of the plant specific, ROXY glutaredoxins and three BHLH transcription factors involved in iron homeostasis were strongly upregulated, supporting a role for GSNOR in redox and iron metabolism. One third of downregulated genes are linked to pathogen resistance, providing further basis for the reported pathogen sensitivity of GSNOR null mutants. Together, these findings indicate GSNOR regulates multiple developmental and metabolic programs in plants and offer insight into putative routes of post-translational GSNOR regulation.
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Affiliation(s)
- Shengbao Xu
- Department of Biochemistry and Molecular Biology, University of Massachusetts-Amherst, Amherst, MA, USA
- School of Life Sciences, Lanzhou University, Gansu, China
| | - Damian Guerra
- Department of Biochemistry and Molecular Biology, University of Massachusetts-Amherst, Amherst, MA, USA
| | - Ung Lee
- Department of Biochemistry and Molecular Biophysics, University of Arizona, Tucson, AZ, USA
| | - Elizabeth Vierling
- Department of Biochemistry and Molecular Biology, University of Massachusetts-Amherst, Amherst, MA, USA
- *Correspondence: Elizabeth Vierling, Life Science Laboratories, University of Massachusetts-Amherst, 240 Thatcher Road, Amherst, MA 01003, USA e-mail:
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Kim M, Lee U, Small I, des Francs-Small CC, Vierling E. Mutations in an Arabidopsis mitochondrial transcription termination factor-related protein enhance thermotolerance in the absence of the major molecular chaperone HSP101. Plant Cell 2012; 24:3349-65. [PMID: 22942382 PMCID: PMC3462636 DOI: 10.1105/tpc.112.101006] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2012] [Revised: 08/01/2012] [Accepted: 08/14/2012] [Indexed: 05/18/2023]
Abstract
The molecular chaperone heat shock protein101 (HSP101) is required for acquired thermotolerance in plants and other organisms. To identify factors that interact with HSP101 or that are involved in thermotolerance, we screened for extragenic suppressors of a dominant-negative allele of Arabidopsis thaliana HSP101, hot1-4. One suppressor, shot1 (for suppressor of hot1-4 1), encodes a mitochondrial transcription termination factor (mTERF)-related protein, one of 35 Arabidopsis mTERFs about which there is limited functional data. Missense (shot1-1) and T-DNA insertion (shot1-2) mutants suppress the hot1-4 heat-hypersensitive phenotype. Furthermore, shot1-2 suppresses other heat-sensitive mutants, and shot1-2 alone is more heat tolerant than the wild type. SHOT1 resides in mitochondria, indicating it functions independently of cytosolic/nuclear HSP101. Microarray analysis suggests altered mitochondrial function and/or retrograde signaling in shot1-2 increases transcripts of other HSPs and alters expression of redox-related genes. Reduced oxidative damage is the likely cause of shot1 thermotolerance, indicating HSP101 repairs protein oxidative damage and/or reduced oxidative damage allows recovery in the absence of HSP101. Changes in organelle-encoded transcripts in shot1 demonstrate that SHOT1 is involved in organelle gene regulation. The heat tolerance of shot1 emphasizes the importance of mitochondria in stress tolerance, and defining its function may provide insights into control of oxidative damage for engineering stress-resistant plants.
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Affiliation(s)
- Minsoo Kim
- School of Plant Sciences, University of Arizona, Tucson, Arizona 85721
| | - Ung Lee
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721
| | - Ian Small
- Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Crawley 6009, Western Australia, Australia
| | - Catherine Colas des Francs-Small
- Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Crawley 6009, Western Australia, Australia
| | - Elizabeth Vierling
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, Massachusetts 01003
- Address correspondence to
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Stengel F, Baldwin AJ, Bush MF, Hilton GR, Lioe H, Basha E, Jaya N, Vierling E, Benesch JL. Dissecting heterogeneous molecular chaperone complexes using a mass spectrum deconvolution approach. Chem Biol 2012; 19:599-607. [PMID: 22633411 PMCID: PMC3458707 DOI: 10.1016/j.chembiol.2012.04.007] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Revised: 04/02/2012] [Accepted: 04/06/2012] [Indexed: 11/30/2022]
Abstract
Small heat-shock proteins (sHSPs) are molecular chaperones that prevent irreversible aggregation through binding nonnative target proteins. Due to their heterogeneity, these sHSP:target complexes remain poorly understood. We present a nanoelectrospray mass spectrometry analysis algorithm for estimating the distribution of stoichiometries comprising a polydisperse ensemble of oligomers. We thus elucidate the organization of complexes formed between sHSPs and different target proteins. We find that binding is mass dependent, with the resultant complexes reflecting the native quaternary architecture of the target, indicating that protection happens early in the denaturation. Our data therefore explain the apparent paradox of how variable complex morphologies result from the generic mechanism of protection afforded by sHSPs. Our approach is applicable to a range of polydisperse proteins and provides a means for the automated and accurate interpretation of mass spectra derived from heterogeneous protein assemblies.
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Affiliation(s)
- Florian Stengel
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford, UK
| | - Andrew J. Baldwin
- Departments of Molecular Genetics, Biochemistry, and Chemistry, University of Toronto, Toronto, ON, Canada
| | - Matthew F. Bush
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford, UK
| | - Gillian R. Hilton
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford, UK
| | - Hadi Lioe
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford, UK
| | - Eman Basha
- Botany Department, Faculty of Science, Tanta University, Tanta, Egypt
- Department of Biochemistry & Molecular Biophysics, University of Arizona, Tucson, AZ, USA
| | - Nomalie Jaya
- Department of Biochemistry & Molecular Biophysics, University of Arizona, Tucson, AZ, USA
| | - Elizabeth Vierling
- Department of Biochemistry & Molecular Biology, University of Massachusetts, Amherst, MA, USA
| | - Justin L.P. Benesch
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford, UK
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Basha E, O'Neill H, Vierling E. Small heat shock proteins and α-crystallins: dynamic proteins with flexible functions. Trends Biochem Sci 2011; 37:106-17. [PMID: 22177323 DOI: 10.1016/j.tibs.2011.11.005] [Citation(s) in RCA: 371] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2011] [Revised: 11/09/2011] [Accepted: 11/14/2011] [Indexed: 12/11/2022]
Abstract
The small heat shock proteins (sHSPs) and the related α-crystallins (αCs) are virtually ubiquitous proteins that are strongly induced by a variety of stresses, but that also function constitutively in multiple cell types in many organisms. Extensive research has demonstrated that a majority of sHSPs and αCs can act as ATP-independent molecular chaperones by binding denaturing proteins and thereby protecting cells from damage due to irreversible protein aggregation. As a result of their diverse evolutionary history, their connection to inherited human diseases, and their novel protein dynamics, sHSPs and αCs are of significant interest to many areas of biology and biochemistry. However, it is increasingly clear that no single model is sufficient to describe the structure, function or mechanism of action of sHSPs and αCs. In this review, we discuss recent data that provide insight into the variety of structures of these proteins, their dynamic behavior, how they recognize substrates, and their many possible cellular roles.
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Affiliation(s)
- Eman Basha
- Department of Chemistry & Biochemistry, 1007 E. Lowell Street, University of Arizona, Tucson, AZ 85743, USA
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Benesch JLP, Aquilina JA, Baldwin AJ, Rekas A, Stengel F, Lindner RA, Basha E, Devlin GL, Horwitz J, Vierling E, Carver JA, Robinson CV. The quaternary organization and dynamics of the molecular chaperone HSP26 are thermally regulated. ACTA ACUST UNITED AC 2011; 17:1008-17. [PMID: 20851350 DOI: 10.1016/j.chembiol.2010.06.016] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2010] [Revised: 06/21/2010] [Accepted: 06/25/2010] [Indexed: 12/18/2022]
Abstract
The function of ScHSP26 is thermally controlled: the heat shock that causes the destabilization of target proteins leads to its activation as a molecular chaperone. We investigate the structural and dynamical properties of ScHSP26 oligomers through a combination of multiangle light scattering, fluorescence spectroscopy, NMR spectroscopy, and mass spectrometry. We show that ScHSP26 exists as a heterogeneous oligomeric ensemble at room temperature. At heat-shock temperatures, two shifts in equilibria are observed: toward dissociation and to larger oligomers. We examine the quaternary dynamics of these oligomers by investigating the rate of exchange of subunits between them and find that this not only increases with temperature but proceeds via two separate processes. This is consistent with a conformational change of the oligomers at elevated temperatures which regulates the disassembly rates of this thermally activated protein.
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Affiliation(s)
- Justin L P Benesch
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, Oxford, UK
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35
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Vierling E, Mishkind ML, Schmidt GW, Key JL. Specific heat shock proteins are transported into chloroplasts. Proc Natl Acad Sci U S A 2010; 83:361-5. [PMID: 16593647 PMCID: PMC322858 DOI: 10.1073/pnas.83.2.361] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We demonstrate that in three plant species-soybean, pea, and corn-certain nuclear-encoded heat shock proteins are transported into chloroplasts. In vitro translation products of poly(A)-RNA from control or heat-shocked plants were incubated with isolated intact pea chloroplasts and differences in the profile of imported proteins were analyzed. In all three species, abundant polypeptides between 21 and 27 kDa are present in the heat shock sample and absent in the controls. These polypeptides are protected from trypsin and chymotrypsin digestion after their import into chloroplasts and are recovered primarily with the soluble chloroplast protein fraction. Chloroplasts isolated from pea or corn leaves labeled in vivo at heat shock temperatures, but not at normal growth temperatures, contain the same polypeptides observed in vitro. Synthesis of the heat shock polypeptides can be inhibited in vivo by cycloheximide but not by chloramphenicol, further indicating they are products of cytoplasmic protein synthesis. The in vitro transport experiments demonstrate that synthesis of the chloroplast-localized heat shock proteins results from heat-induced accumulation of the corresponding poly(A)-RNAs. The same mRNAs are also produced in response to heat shock by a nonphotosynthetic tissue, the etiolated soybean hypocotyl.
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Affiliation(s)
- E Vierling
- Department of Botany, University of Georgia, Athens, GA 30602
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36
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Basha E, Jones C, Wysocki V, Vierling E. Mechanistic differences between two conserved classes of small heat shock proteins found in the plant cytosol. J Biol Chem 2010; 285:11489-97. [PMID: 20145254 PMCID: PMC2857027 DOI: 10.1074/jbc.m109.074088] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2009] [Revised: 01/30/2010] [Indexed: 11/06/2022] Open
Abstract
The small heat shock proteins (sHSPs) and alpha-crystallins are highly effective, ATP-independent chaperones that can bind denaturing client proteins to prevent their irreversible aggregation. One model of sHSP function suggests that the oligomeric sHSPs are activated to the client-binding form by dissociation at elevated temperatures to dimers or other sub-oligomeric species. Here we examine this model in a comparison of the oligomeric structure and chaperone activity of two conserved classes of cytosolic sHSPs in plants, the class I (CI) and class II (CII) proteins. Like the CI sHSPs, recombinant CII sHSPs from three divergent plant species, pea, wheat, and Arabidopsis, are dodecamers as determined by nano-electrospray mass spectrometry. While at 35 to 45 degrees C, all three CI sHSPs reversibly dissociate to dimers, the CII sHSPs retain oligomeric structure at high temperature. The CII dodecamers are, however, dynamic and rapidly exchange subunits, but unlike CI sHSPs, the exchange unit appears larger than a dimer. Differences in dodecameric structure are also reflected in the fact that the CII proteins do not hetero-oligomerize with CI sHSPs. Binding of the hydrophobic probe bis-ANS and limited proteolysis demonstrate CII proteins undergo significant, reversible structural changes at high temperature. All three recombinant CII proteins more efficiently protect firefly luciferase from insolubilization during heating than do the CI proteins. The CI and CII proteins behave strictly additively in client protection. In total, the results demonstrate that different sHSPs can achieve effective protection of client proteins by varied mechanisms.
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Affiliation(s)
- Eman Basha
- From the Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721
| | - Christopher Jones
- From the Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721
| | - Vicki Wysocki
- From the Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721
| | - Elizabeth Vierling
- From the Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721
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Stengel F, Baldwin AJ, Painter AJ, Jaya N, Basha E, Kay LE, Vierling E, Robinson CV, Benesch JLP. Quaternary dynamics and plasticity underlie small heat shock protein chaperone function. Proc Natl Acad Sci U S A 2010; 107:2007-12. [PMID: 20133845 PMCID: PMC2836621 DOI: 10.1073/pnas.0910126107] [Citation(s) in RCA: 197] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Small Heat Shock Proteins (sHSPs) are a diverse family of molecular chaperones that prevent protein aggregation by binding clients destabilized during cellular stress. Here we probe the architecture and dynamics of complexes formed between an oligomeric sHSP and client by employing unique mass spectrometry strategies. We observe over 300 different stoichiometries of interaction, demonstrating that an ensemble of structures underlies the protection these chaperones confer to unfolding clients. This astonishing heterogeneity not only makes the system quite distinct in behavior to ATP-dependent chaperones, but also renders it intractable by conventional structural biology approaches. We find that thermally regulated quaternary dynamics of the sHSP establish and maintain the plasticity of the system. This extends the paradigm that intrinsic dynamics are crucial to protein function to include equilibrium fluctuations in quaternary structure, and suggests they are integral to the sHSPs' role in the cellular protein homeostasis network.
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Affiliation(s)
- Florian Stengel
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, and Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford, OX1 3QZ United Kingdom
| | - Andrew J. Baldwin
- Departments of Molecular Genetics, Biochemistry, and Chemistry, University of Toronto, Toronto, ON, M5S 1A8, Canada; and
| | - Alexander J. Painter
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, and Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford, OX1 3QZ United Kingdom
| | - Nomalie Jaya
- Department of Chemistry & Biochemistry, University of Arizona, Tucson, AZ, 85721
| | - Eman Basha
- Department of Chemistry & Biochemistry, University of Arizona, Tucson, AZ, 85721
| | - Lewis E. Kay
- Departments of Molecular Genetics, Biochemistry, and Chemistry, University of Toronto, Toronto, ON, M5S 1A8, Canada; and
| | - Elizabeth Vierling
- Department of Chemistry & Biochemistry, University of Arizona, Tucson, AZ, 85721
| | - Carol V. Robinson
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, and Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford, OX1 3QZ United Kingdom
| | - Justin L. P. Benesch
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, and Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford, OX1 3QZ United Kingdom
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38
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Jaya N, Garcia V, Vierling E. Substrate binding site flexibility of the small heat shock protein molecular chaperones. Proc Natl Acad Sci U S A 2009; 106:15604-9. [PMID: 19717454 PMCID: PMC2773522 DOI: 10.1073/pnas.0902177106] [Citation(s) in RCA: 181] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2009] [Indexed: 11/18/2022] Open
Abstract
Small heat shock proteins (sHSPs) serve as a first line of defense against stress-induced cell damage by binding and maintaining denaturing proteins in a folding-competent state. In contrast to the well-defined substrate binding regions of ATP-dependent chaperones, interactions between sHSPs and substrates are poorly understood. Defining substrate-binding sites of sHSPs is key to understanding their cellular functions and to harnessing their aggregation-prevention properties for controlling damage due to stress and disease. We incorporated a photoactivatable cross-linker at 32 positions throughout a well-characterized sHSP, dodecameric PsHsp18.1 from pea, and identified direct interaction sites between sHSPs and substrates. Model substrates firefly luciferase and malate dehydrogenase form strong contacts with multiple residues in the sHSP N-terminal arm, demonstrating the importance of this flexible and evolutionary variable region in substrate binding. Within the conserved alpha-crystallin domain both substrates also bind the beta-strand (beta7) where mutations in human homologs result in inherited disease. Notably, these binding sites are poorly accessible in the sHSP atomic structure, consistent with major structural rearrangements being required for substrate binding. Detectable differences in the pattern of cross-linking intensity of the two substrates and the fact that substrates make contacts throughout the sHSP indicate that there is not a discrete substrate binding surface. Our results support a model in which the intrinsically-disordered N-terminal arm can present diverse geometries of interaction sites, which is likely critical for the ability of sHSPs to protect efficiently many different substrates.
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Affiliation(s)
- Nomalie Jaya
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721
| | - Victor Garcia
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721
| | - Elizabeth Vierling
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721
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39
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Jaya N, Garcia V, Vierling E. Identification of substrate binding sites on a small heat shock protein reveals a unique mode of interaction between differentially aggregating substrates. FASEB J 2009. [DOI: 10.1096/fasebj.23.1_supplement.673.6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Nomalie Jaya
- Biochemistry and Molecular BiophysicsUniversity of ArizonaTucsonAZ
| | - Victor Garcia
- Biochemistry and Molecular BiophysicsUniversity of ArizonaTucsonAZ
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40
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Cheng G, Basha E, Wysocki VH, Vierling E. Insights into small heat shock protein and substrate structure during chaperone action derived from hydrogen/deuterium exchange and mass spectrometry. J Biol Chem 2008; 283:26634-42. [PMID: 18621732 PMCID: PMC2546550 DOI: 10.1074/jbc.m802946200] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2008] [Revised: 06/09/2008] [Indexed: 01/02/2023] Open
Abstract
Small heat shock proteins (sHSPs) and the related alpha-crystallins are ubiquitous chaperones linked to neurodegenerative diseases, myopathies, and cataract. To better define their mechanism of chaperone action, we used hydrogen/deuterium exchange and mass spectrometry (HXMS) to monitor conformational changes during complex formation between the structurally defined sHSPs, pea PsHsp18.1, and wheat TaHsp16.9, and the heat-denatured model substrates malate dehydrogenase (MDH) and firefly luciferase. Remarkably, we found that even when complexed with substrate, the highly dynamic local structure of the sHSPs, especially in the N-terminal arm (>70% exchange in 5 s), remains unchanged. These results, coupled with sHSP-substrate complex stability, indicate that sHSPs do not adopt new secondary structure when binding substrate and suggest sHSPs are tethered to substrate at multiple sites that are locally dynamic, a feature that likely facilitates recognition and refolding of sHSP-bound substrate by the Hsp70/DnaK chaperone system. Both substrates were found to be stabilized in a partially unfolded state that is observed only in the presence of sHSP. Furthermore, peptide-level HXMS showed MDH was substantially protected in two core regions (residues 95-156 and 228-252), which overlap with the MDH structure protected in the GroEL-bound MDH refolding intermediate. Significantly, despite differences in the size and structure of TaHsp16.9-MDH and PsHsp18.1-MDH complexes, peptide-level HXMS patterns for MDH in both complexes are virtually identical, indicating that stabilized MDH thermal unfolding intermediates are not determined by the identity of the sHSP.
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Affiliation(s)
- Guilong Cheng
- Departments of Chemistry and
Biochemistry and Molecular Biophysics,
University of Arizona, Tucson, Arizona 85721
| | - Eman Basha
- Departments of Chemistry and
Biochemistry and Molecular Biophysics,
University of Arizona, Tucson, Arizona 85721
| | - Vicki H. Wysocki
- Departments of Chemistry and
Biochemistry and Molecular Biophysics,
University of Arizona, Tucson, Arizona 85721
| | - Elizabeth Vierling
- Departments of Chemistry and
Biochemistry and Molecular Biophysics,
University of Arizona, Tucson, Arizona 85721
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41
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Balogi Z, Cheregi O, Giese KC, Juhász K, Vierling E, Vass I, Vígh L, Horváth I. A mutant small heat shock protein with increased thylakoid association provides an elevated resistance against UV-B damage in synechocystis 6803. J Biol Chem 2008; 283:22983-91. [PMID: 18574246 DOI: 10.1074/jbc.m710400200] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Besides acting as molecular chaperones, the amphitropic small heat shock proteins (sHsps) are suggested to play an additional role in membrane quality control. We investigated sHsp membrane function in the model cyanobacterium Synechocystis sp. PPC 6803 using mutants of the single sHsp from this organism, Hsp17. We examined mutants in the N-terminal arm, L9P and Q16R, for altered interaction with thylakoid and lipid membranes and examined the effects of these mutations on thylakoid functions. These mutants are unusual in that they retain their oligomeric state and chaperone activity in vitro but fail to confer thermotolerance in vivo. We found that both mutant proteins had dramatically altered membrane/lipid interaction properties. Whereas L9P showed strongly reduced binding to thylakoid and model membranes, Q16R was almost exclusively membrane-associated, properties that may be the cause of reduced heat tolerance of cells carrying these mutations. Among the lipid classes tested, Q16R displayed the highest interaction with negatively charged SQDG. In Q16R cells a specific alteration of the thylakoid-embedded Photosystem II (PSII) complex was observed. Namely, the binding of plastoquinone and quinone analogue acceptors to the Q(B) site was modified. In addition, the presence of Q16R dramatically reduced UV-B damage of PSII activity because of enhanced PSII repair. We suggest these effects occur at least partly because of increased interaction of Q16R with SQDG in the PSII complex. Our findings further support the model that membrane association is a functional property of sHsps and suggest sHsps as a possible biotechnological tool to enhance UV protection of photosynthetic organisms.
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Affiliation(s)
- Zsolt Balogi
- Department of Plant Biology, Biological Research Center, Hungarian Academy of Sciences, H-6701 Szeged, Hungary
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42
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Siddique M, Gernhard S, von Koskull-Döring P, Vierling E, Scharf KD. The plant sHSP superfamily: five new members in Arabidopsis thaliana with unexpected properties. Cell Stress Chaperones 2008; 13:183-97. [PMID: 18369739 PMCID: PMC2673886 DOI: 10.1007/s12192-008-0032-6] [Citation(s) in RCA: 156] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2007] [Revised: 11/09/2007] [Accepted: 11/14/2007] [Indexed: 10/22/2022] Open
Abstract
The small heat shock proteins (sHsps), which are ubiquitous stress proteins proposed to act as chaperones, are encoded by an unusually complex gene family in plants. Plant sHsps are classified into different subfamilies according to amino acid sequence similarity and localization to distinct subcellular compartments. In the whole Arabidopsis thaliana genome, 19 genes were annotated to encode sHsps, of which 14 belong to previously defined plant sHsp families. In this paper, we report studies of the five additional sHsp genes in A. thaliana, which can now be shown to represent evolutionarily distinct sHsp subfamilies also found in other plant species. While two of these five sHsps show expression patterns typical of the other 14 genes, three have unusual tissue specific and developmental profiles and do not respond to heat induction. Analysis of intracellular targeting indicates that one sHsp represents a new class of mitochondrion-targeted sHsps, while the others are cytosolic/nuclear, some of which may cooperate with other sHsps in formation of heat stress granules. Three of the five new proteins were purified and tested for chaperone activity in vitro. Altogether, these studies complete our basic understanding of the sHsp chaperone family in plants.
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Affiliation(s)
- Masood Siddique
- Molecular Cell Biology, Johann Wolfgang Goethe University, Biocenter N200, 3.OG, Max-von-Laue-Str. 9, 60438 Frankfurt am Main, Germany
- Department of Biochemistry II, University Hospital, Johann Wolfgang Goethe University, Theodor-Stern-Kai 7, 60596 Frankfurt am Main, Germany
| | - Sascha Gernhard
- Molecular Cell Biology, Johann Wolfgang Goethe University, Biocenter N200, 3.OG, Max-von-Laue-Str. 9, 60438 Frankfurt am Main, Germany
- Department of Biochemistry II, University Hospital, Johann Wolfgang Goethe University, Theodor-Stern-Kai 7, 60596 Frankfurt am Main, Germany
| | - Pascal von Koskull-Döring
- Molecular Cell Biology, Johann Wolfgang Goethe University, Biocenter N200, 3.OG, Max-von-Laue-Str. 9, 60438 Frankfurt am Main, Germany
| | - Elizabeth Vierling
- Department of Biochemistry and Molecular Biophysics, University of Arizona, 1007 E Lowell Street, Tucson, AZ 85721 USA
| | - Klaus-Dieter Scharf
- Molecular Cell Biology, Johann Wolfgang Goethe University, Biocenter N200, 3.OG, Max-von-Laue-Str. 9, 60438 Frankfurt am Main, Germany
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43
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Lee U, Wie C, Fernandez BO, Feelisch M, Vierling E. Modulation of nitrosative stress by S-nitrosoglutathione reductase is critical for thermotolerance and plant growth in Arabidopsis. Plant Cell 2008; 20:786-802. [PMID: 18326829 PMCID: PMC2329944 DOI: 10.1105/tpc.107.052647] [Citation(s) in RCA: 236] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2007] [Revised: 02/04/2008] [Accepted: 02/15/2008] [Indexed: 05/18/2023]
Abstract
Nitric oxide (NO) is a key signaling molecule in plants. This analysis of Arabidopsis thaliana HOT5 (sensitive to hot temperatures), which is required for thermotolerance, uncovers a role of NO in thermotolerance and plant development. HOT5 encodes S-nitrosoglutathione reductase (GSNOR), which metabolizes the NO adduct S-nitrosoglutathione. Two hot5 missense alleles and two T-DNA insertion, protein null alleles were characterized. The missense alleles cannot acclimate to heat as dark-grown seedlings but grow normally and can heat-acclimate in the light. The null alleles cannot heat-acclimate as light-grown plants and have other phenotypes, including failure to grow on nutrient plates, increased reproductive shoots, and reduced fertility. The fertility defect of hot5 is due to both reduced stamen elongation and male and female fertilization defects. The hot5 null alleles show increased nitrate and nitroso species levels, and the heat sensitivity of both missense and null alleles is associated with increased NO species. Heat sensitivity is enhanced in wild-type and mutant plants by NO donors, and the heat sensitivity of hot5 mutants can be rescued by an NO scavenger. An NO-overproducing mutant is also defective in thermotolerance. Together, our results expand the importance of GSNOR-regulated NO homeostasis to abiotic stress and plant development.
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Affiliation(s)
- Ung Lee
- Department of Biochemistry and Molecular Biophysics, University of Arizona, Tucson, Arizona 85721, USA
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44
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Tonsor SJ, Scott C, Boumaza I, Liss TR, Brodsky JL, Vierling E. Heat shock protein 101 effects in A. thaliana: genetic variation, fitness and pleiotropy in controlled temperature conditions. Mol Ecol 2008; 17:1614-26. [PMID: 18321256 PMCID: PMC2727869 DOI: 10.1111/j.1365-294x.2008.03690.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The Hsp100/ClpB heat shock protein family is ancient and required for high temperature survival, but natural variation in expression and its phenotypic effects is unexplored in plants. In controlled environment experiments, we examined the effects of variation in the Arabidopsis cytosolic AtHsp101 (hereafter Hsp101). Ten wild-collected ecotypes differed in Hsp101 expression responses across a 22 to 40 degrees C gradient. Genotypes from low latitudes expressed the least Hsp101. We tested fitness and pleiotropic consequences of varying Hsp101 expression in 'control' vs. mild thermal stress treatments (15/25 degrees C D/N vs. 15/25 degrees D/N plus 3 h at 35 degrees C 3 days/week). Comparing wild type and null mutants, wt Columbia (Col) produced approximately 33% more fruits compared to its Hsp101 homozygous null mutant. There was no difference between Landsberg erecta null mutant NIL (Ler) and wt Ler; wt Ler showed very low Hsp101 expression. In an assay of six genotypes, fecundity was a saturating function of Hsp101 content, in both experimental treatments. Thus, in addition to its essential role in acquired thermal tolerance, Hsp101 provides a substantial fitness benefit under normal growth conditions. Knocking out Hsp101 decreased fruit production, days to germination and days to bolting, total dry mass, and number of inflorescences; it increased transpiration rate and allocation to root mass. Root : total mass ratio decayed exponentially with Hsp101 content. This study shows that Hsp101 expression is evolvable in natural populations. Our results further suggest that Hsp101 is primarily an emergency high-temperature tolerance mechanism, since expression levels are lower in low-latitude populations from warmer climates. Hsp101 expression appears to carry an important trade-off in reduced root growth. This trade-off may select for suppressed expression under chronically high temperatures.
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Affiliation(s)
- S J Tonsor
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA.
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45
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Painter AJ, Jaya N, Basha E, Vierling E, Robinson CV, Benesch JL. Real-Time Monitoring of Protein Complexes Reveals their Quaternary Organization and Dynamics. ACTA ACUST UNITED AC 2008; 15:246-53. [DOI: 10.1016/j.chembiol.2008.01.009] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2007] [Revised: 01/28/2008] [Accepted: 01/30/2008] [Indexed: 10/22/2022]
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46
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Paul MR, Basha E, Vierling E. Investigating the role of the eukaryotic elongation factors 1B‐α (1, 2) and eEF1B‐β (1, 2) from
Arabidopsis thaliana
in plant thermotolerance. FASEB J 2008. [DOI: 10.1096/fasebj.22.1_supplement.841.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Megan Rose Paul
- Biochemistry and Molecular BiophysicsUniversity of ArizonaTucsonAZ
| | - Eman Basha
- Biochemistry and Molecular BiophysicsUniversity of ArizonaTucsonAZ
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Larkindale J, Vierling E. Core genome responses involved in acclimation to high temperature. Plant Physiol 2008; 146:748-61. [PMID: 18055584 PMCID: PMC2245833 DOI: 10.1104/pp.107.112060] [Citation(s) in RCA: 282] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2007] [Accepted: 11/19/2007] [Indexed: 05/17/2023]
Abstract
Plants can acclimate rapidly to environmental conditions, including high temperatures. To identify molecular events important for acquired thermotolerance, we compared viability and transcript profiles of Arabidopsis thaliana treated to severe heat stress (45 degrees C) without acclimation or following two different acclimation treatments. Notably, a gradual increase to 45 degrees C (22 degrees C to 45 degrees C over 6 h) led to higher survival and to more and higher-fold transcript changes than a step-wise acclimation (90 min at 38 degrees C plus 120 min at 22 degrees C before 45 degrees C). There were significant differences in the total spectrum of transcript changes in the two treatments, but core components of heat acclimation were apparent in the overlap between treatments, emphasizing the importance of performing transcriptome analysis in the context of physiological response. In addition to documenting increases in transcripts of specific genes involved in processes predicted to be required for thermotolerance (i.e. protection of proteins and of translation, limiting oxidative stress), we also found decreases in transcripts (i.e. for programmed cell death, basic metabolism, and biotic stress responses), which are likely equally important for acclimation. Similar protective effects may also be achieved differently, such as prevention of proline accumulation, which is toxic at elevated temperatures and which was reduced by both acclimation treatments but was associated with transcript changes predicted to either reduce proline synthesis or increase degradation in the two acclimation treatments. Finally, phenotypic analysis of T-DNA insertion mutants of genes identified in this analysis defined eight new genes involved in heat acclimation, including cytosolic ascorbate peroxidase and the transcription factors HsfA7a (heat shock transcription factor A7a) and NF-X1.
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Affiliation(s)
- Jane Larkindale
- Department of Biochemistry and Molecular Biophysics, University of Arizona, Tucson, Arizona 85721, USA
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Schramm F, Larkindale J, Kiehlmann E, Ganguli A, Englich G, Vierling E, von Koskull-Döring P. A cascade of transcription factor DREB2A and heat stress transcription factor HsfA3 regulates the heat stress response of Arabidopsis. Plant J 2008. [PMID: 17999647 DOI: 10.1111/j.1365-313xx.2007.03334.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
The dehydration-responsive element binding protein (DREB)/C-repeat binding factor (CBF) family are the classical transcriptional regulators involved in plant responses to drought, salt and cold stress. Recently it was demonstrated that DREB2A is induced by heat stress (hs) and is a regulator of the hs response of Arabidopsis. Here we provide molecular insights into the regulation and function of hs transcription factor HsfA3. Among the 21 members of the Arabidopsis Hsf family, HsfA3 is the only Hsf that is transcriptionally induced during hs by DREB2A, and HsfA3 in turn regulates the expression of Hsp-encoding genes. This transcription factor cascade was reconstructed in transient GUS reporter assays in mesophyll protoplasts by showing that DREB2A could activate the HsfA3 promoter, whereas HsfA3 in turn was shown to be a potent activator on the promoters of Hsp genes. Direct binding to the corresponding promoters was demonstrated by electrophoretic mobility shift assays, and the involvement of HsfA3 in the hs response in vivo was shown directly by observation of reduced thermotolerance in HsfA3 mutant lines. Altogether these data demonstrate that HsfA3 is transcriptionally controlled by DREB2A and important for the establishment of thermotolerance.
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Affiliation(s)
- Franziska Schramm
- Institute of Molecular Biosciences, Biocenter N200/R306, Goethe University Frankfurt, Max-von-Laue-Str. 9, D-60438 Frankfurt, Germany
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Schramm F, Larkindale J, Kiehlmann E, Ganguli A, Englich G, Vierling E, von Koskull-Döring P. A cascade of transcription factor DREB2A and heat stress transcription factor HsfA3 regulates the heat stress response of Arabidopsis. Plant J 2008; 53:264-74. [PMID: 17999647 DOI: 10.1111/j.1365-313x.2007.03334.x] [Citation(s) in RCA: 251] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
The dehydration-responsive element binding protein (DREB)/C-repeat binding factor (CBF) family are the classical transcriptional regulators involved in plant responses to drought, salt and cold stress. Recently it was demonstrated that DREB2A is induced by heat stress (hs) and is a regulator of the hs response of Arabidopsis. Here we provide molecular insights into the regulation and function of hs transcription factor HsfA3. Among the 21 members of the Arabidopsis Hsf family, HsfA3 is the only Hsf that is transcriptionally induced during hs by DREB2A, and HsfA3 in turn regulates the expression of Hsp-encoding genes. This transcription factor cascade was reconstructed in transient GUS reporter assays in mesophyll protoplasts by showing that DREB2A could activate the HsfA3 promoter, whereas HsfA3 in turn was shown to be a potent activator on the promoters of Hsp genes. Direct binding to the corresponding promoters was demonstrated by electrophoretic mobility shift assays, and the involvement of HsfA3 in the hs response in vivo was shown directly by observation of reduced thermotolerance in HsfA3 mutant lines. Altogether these data demonstrate that HsfA3 is transcriptionally controlled by DREB2A and important for the establishment of thermotolerance.
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Affiliation(s)
- Franziska Schramm
- Institute of Molecular Biosciences, Biocenter N200/R306, Goethe University Frankfurt, Max-von-Laue-Str. 9, D-60438 Frankfurt, Germany
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50
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McLellan CA, Turbyville TJ, Wijeratne EMK, Kerschen A, Vierling E, Queitsch C, Whitesell L, Gunatilaka AAL. A rhizosphere fungus enhances Arabidopsis thermotolerance through production of an HSP90 inhibitor. Plant Physiol 2007; 145:174-82. [PMID: 17631526 PMCID: PMC1976574 DOI: 10.1104/pp.107.101808] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The molecular chaperone HEAT SHOCK PROTEIN90 (HSP90) is essential for the maturation of key regulatory proteins in eukaryotes and for the response to temperature stress. Earlier, we have reported that fungi living in association with plants of the Sonoran desert produce small molecule inhibitors of mammalian HSP90. Here, we address whether elaboration of the HSP90 inhibitor monocillin I (MON) by the rhizosphere fungus Paraphaeosphaeria quadriseptata affects plant HSP90 and plant environmental responsiveness. We demonstrate that MON binds Arabidopsis (Arabidopsis thaliana) HSP90 and can inhibit the function of HSP90 in lysates of wheat (Triticum aestivum) germ. MON treatment of Arabidopsis seedlings induced HSP101 and HSP70, conserved components of the stress response. Application of MON, or growth in the presence of MON, allowed Arabidopsis wild type but not AtHSP101 knockout mutant seedlings to survive otherwise lethal temperature stress. Finally, cocultivation of P. quadriseptata with Arabidopsis enhanced plant heat stress tolerance. These data demonstrate that HSP90-inhibitory compounds produced by fungi can influence plant growth and responses to the environment.
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