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Buggiani J, Meinnel T, Giglione C, Frottin F. Advances in nuclear proteostasis of metazoans. Biochimie 2024:S0300-9084(24)00081-6. [PMID: 38642824 DOI: 10.1016/j.biochi.2024.04.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Revised: 04/12/2024] [Accepted: 04/16/2024] [Indexed: 04/22/2024]
Abstract
The proteostasis network and associated protein quality control (PQC) mechanisms ensure proteome functionality and are essential for cell survival. A distinctive feature of eukaryotic cells is their high degree of compartmentalization, requiring specific and adapted proteostasis networks for each compartment. The nucleus, essential for maintaining the integrity of genetic information and gene transcription, is one such compartment. While PQC mechanisms have been investigated for decades in the cytoplasm and the endoplasmic reticulum, our knowledge of nuclear PQC pathways is only emerging. Recent developments in the field have underscored the importance of spatially managing aberrant proteins within the nucleus. Upon proteotoxic stress, misfolded proteins and PQC effectors accumulate in various nuclear membrane-less organelles. Beyond bringing together effectors and substrates, the biophysical properties of these organelles allow novel PQC functions. In this review, we explore the specificity of the nuclear compartment, the effectors of the nuclear proteostasis network, and the PQC roles of nuclear membrane-less organelles in metazoans.
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Affiliation(s)
- Julia Buggiani
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Gif-sur-Yvette, France
| | - Thierry Meinnel
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Gif-sur-Yvette, France
| | - Carmela Giglione
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Gif-sur-Yvette, France
| | - Frédéric Frottin
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Gif-sur-Yvette, France.
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2
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Wang F, Dezfouli AB, Khosravi M, Sievert W, Stangl S, Schwab M, Wu Z, Steiger K, Ma H, Multhoff G. Cannabidiol-induced crosstalk of apoptosis and macroautophagy in colorectal cancer cells involves p53 and Hsp70. Cell Death Discov 2023; 9:286. [PMID: 37542074 PMCID: PMC10403543 DOI: 10.1038/s41420-023-01578-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 07/12/2023] [Accepted: 07/25/2023] [Indexed: 08/06/2023] Open
Abstract
Although it has been established that cannabidiol (CBD), the major non-psychoactive constituent of cannabis, exerts antitumoral activities, the exact mechanism(s) via which tumor cells are killed by CBD are not well understood. This study provides new insights into the potential mechanisms of CBD-induced mutual antagonism of apoptosis and macroautophagy using wild type (HCT116 p53wt, LS174T p53wt), knockout (HCT116 p53-/-) and mutant (SW480 p53mut) human colorectal cancer cells (CRC). CBD causes a more pronounced loss in the viability of p53wt cells than p53-/- and p53mut cells, and a 5-week treatment with CBD reduced the volume of HCT116 p53wt xenografts in mice, but had no effect on the volume of HCT116 p53-/- tumors. Mechanistically, we demonstrate that CBD only significantly elevates ROS production in cells harboring wild-type p53 (HCT116, LS174T) and that this is associated with an accumulation of PARP1. CBD-induced elevated ROS levels trigger G0/G1 cell cycle arrest, a reduction in CDK2, a p53-dependent caspase-8/9/3 activation and macroautophagy in p53wt cells. The ROS-induced macroautophagy which promotes the activation of keap1/Nrf2 pathway might be positively regulated by p53wt, since inhibition of p53 by pifithrin-α further attenuates autophagy after CBD treatment. Interestingly, an inhibition of heat shock protein 70 (Hsp70) expression significantly enhances caspase-3 mediated programmed cell death in p53wt cells, whereas autophagy-which is associated with a nuclear translocation of Nrf2-was blocked. Taken together, our results demonstrate an intricate interplay between apoptosis and macroautophagy in CBD-treated colorectal cancer cells, which is regulated by the complex interactions of p53wt and Hsp70.
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Affiliation(s)
- Fei Wang
- Radiation Immuno-Oncology Project Group, TranslaTUM-Central Institute for Translational Cancer Research, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.
- Department of Oncology, The Second Affiliated Hospital of Zunyi Medical University, Zunyi, China.
| | - Ali Bashiri Dezfouli
- Radiation Immuno-Oncology Project Group, TranslaTUM-Central Institute for Translational Cancer Research, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Mohammad Khosravi
- Department of Pathobiology, Faculty of Veterinary Medicine, Shahid Chamran University of Ahvaz, Ahvaz, Iran
| | - Wolfgang Sievert
- Radiation Immuno-Oncology Project Group, TranslaTUM-Central Institute for Translational Cancer Research, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Stefan Stangl
- Radiation Immuno-Oncology Project Group, TranslaTUM-Central Institute for Translational Cancer Research, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Melissa Schwab
- Radiation Immuno-Oncology Project Group, TranslaTUM-Central Institute for Translational Cancer Research, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Zhiyuan Wu
- Radiation Immuno-Oncology Project Group, TranslaTUM-Central Institute for Translational Cancer Research, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Katja Steiger
- Institute for General Pathology and Pathological Anatomy, Technische Universität München, Munich, Germany
| | - Hu Ma
- Department of Oncology, The Second Affiliated Hospital of Zunyi Medical University, Zunyi, China
| | - Gabriele Multhoff
- Radiation Immuno-Oncology Project Group, TranslaTUM-Central Institute for Translational Cancer Research, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
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3
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Pande S, Ghosh DK. Nuclear proteostasis imbalance in laminopathy-associated premature aging diseases. FASEB J 2023; 37:e23116. [PMID: 37498235 DOI: 10.1096/fj.202300878r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 06/15/2023] [Accepted: 07/13/2023] [Indexed: 07/28/2023]
Abstract
Laminopathies are a group of rare genetic disorders with heterogeneous clinical phenotypes such as premature aging, cardiomyopathy, lipodystrophy, muscular dystrophy, microcephaly, epilepsy, and so on. The cellular phenomena associated with laminopathy invariably show disruption of nucleoskeleton of lamina due to deregulated expression, localization, function, and interaction of mutant lamin proteins. Impaired spatial and temporal tethering of lamin proteins to the lamina or nucleoplasmic aggregation of lamins are the primary molecular events that can trigger nuclear proteotoxicity by modulating differential protein-protein interactions, sequestering quality control proteins, and initiating a cascade of abnormal post-translational modifications. Clearly, laminopathic cells exhibit moderate to high nuclear proteotoxicity, raising the question of whether an imbalance in nuclear proteostasis is involved in laminopathic diseases, particularly in diseases of early aging such as HGPS and laminopathy-associated premature aging. Here, we review nuclear proteostasis and its deregulation in the context of lamin proteins and laminopathies.
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Affiliation(s)
- Shruti Pande
- Department of Medical Genetics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India
| | - Debasish Kumar Ghosh
- Enteric Disease Division, Department of Microbiology, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India
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4
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Park D, Yu Y, Kim JH, Lee J, Park J, Hong K, Seo JK, Lim C, Min KT. Suboptimal Mitochondrial Activity Facilitates Nuclear Heat Shock Responses for Proteostasis and Genome Stability. Mol Cells 2023; 46:374-386. [PMID: 37077029 PMCID: PMC10258458 DOI: 10.14348/molcells.2023.2181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 01/16/2023] [Accepted: 01/17/2023] [Indexed: 04/21/2023] Open
Abstract
Thermal stress induces dynamic changes in nuclear proteins and relevant physiology as a part of the heat shock response (HSR). However, how the nuclear HSR is fine-tuned for cellular homeostasis remains elusive. Here, we show that mitochondrial activity plays an important role in nuclear proteostasis and genome stability through two distinct HSR pathways. Mitochondrial ribosomal protein (MRP) depletion enhanced the nucleolar granule formation of HSP70 and ubiquitin during HSR while facilitating the recovery of damaged nuclear proteins and impaired nucleocytoplasmic transport. Treatment of the mitochondrial proton gradient uncoupler masked MRP-depletion effects, implicating oxidative phosphorylation in these nuclear HSRs. On the other hand, MRP depletion and a reactive oxygen species (ROS) scavenger non-additively decreased mitochondrial ROS generation during HSR, thereby protecting the nuclear genome from DNA damage. These results suggest that suboptimal mitochondrial activity sustains nuclear homeostasis under cellular stress, providing plausible evidence for optimal endosymbiotic evolution via mitochondria-to-nuclear communication.
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Affiliation(s)
- Dongkeun Park
- Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Korea
| | - Youngim Yu
- Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Korea
| | - Ji-hyung Kim
- Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Korea
| | - Jongbin Lee
- Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Korea
| | - Jongmin Park
- Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Korea
| | - Kido Hong
- Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Korea
| | - Jeong-Kon Seo
- UNIST Central Research Facilities (UCRF), Ulsan National Institute of Science and Technology, Ulsan 44919, Korea
| | - Chunghun Lim
- Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Korea
| | - Kyung-Tai Min
- Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Korea
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5
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Sontag EM, Morales-Polanco F, Chen JH, McDermott G, Dolan PT, Gestaut D, Le Gros MA, Larabell C, Frydman J. Nuclear and cytoplasmic spatial protein quality control is coordinated by nuclear-vacuolar junctions and perinuclear ESCRT. Nat Cell Biol 2023; 25:699-713. [PMID: 37081164 DOI: 10.1038/s41556-023-01128-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 03/14/2023] [Indexed: 04/22/2023]
Abstract
Effective protein quality control (PQC), essential for cellular health, relies on spatial sequestration of misfolded proteins into defined inclusions. Here we reveal the coordination of nuclear and cytoplasmic spatial PQC. Cytoplasmic misfolded proteins concentrate in a cytoplasmic juxtanuclear quality control compartment, while nuclear misfolded proteins sequester into an intranuclear quality control compartment (INQ). Particle tracking reveals that INQ and the juxtanuclear quality control compartment converge to face each other across the nuclear envelope at a site proximal to the nuclear-vacuolar junction marked by perinuclear ESCRT-II/III protein Chm7. Strikingly, convergence at nuclear-vacuolar junction contacts facilitates VPS4-dependent vacuolar clearance of misfolded cytoplasmic and nuclear proteins, the latter entailing extrusion of nuclear INQ into the vacuole. Finding that nuclear-vacuolar contact sites are cellular hubs of spatial PQC to facilitate vacuolar clearance of nuclear and cytoplasmic inclusions highlights the role of cellular architecture in proteostasis maintenance.
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Affiliation(s)
- Emily M Sontag
- Department of Biology, Stanford University, Stanford, CA, USA.
- Department of Biological Sciences, Marquette University, Milwaukee, WI, USA.
| | | | - Jian-Hua Chen
- Department of Anatomy, School of Medicine, University of California San Francisco, San Francisco, CA, USA
| | - Gerry McDermott
- Department of Anatomy, School of Medicine, University of California San Francisco, San Francisco, CA, USA
| | - Patrick T Dolan
- Department of Biology, Stanford University, Stanford, CA, USA
- Quantitative Virology and Evolution Unit, National Institute of Allergy and Infectious Diseases, Bethesda, MD, USA
| | - Daniel Gestaut
- Department of Biology, Stanford University, Stanford, CA, USA
| | - Mark A Le Gros
- Department of Anatomy, School of Medicine, University of California San Francisco, San Francisco, CA, USA
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Carolyn Larabell
- Department of Anatomy, School of Medicine, University of California San Francisco, San Francisco, CA, USA
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Judith Frydman
- Department of Biology, Stanford University, Stanford, CA, USA.
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6
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Kohler V, Andréasson C. Reversible protein assemblies in the proteostasis network in health and disease. Front Mol Biosci 2023; 10:1155521. [PMID: 37021114 PMCID: PMC10067754 DOI: 10.3389/fmolb.2023.1155521] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 03/09/2023] [Indexed: 04/07/2023] Open
Abstract
While proteins populating their native conformations constitute the functional entities of cells, protein aggregates are traditionally associated with cellular dysfunction, stress and disease. During recent years, it has become clear that large aggregate-like protein condensates formed via liquid-liquid phase separation age into more solid aggregate-like particles that harbor misfolded proteins and are decorated by protein quality control factors. The constituent proteins of the condensates/aggregates are disentangled by protein disaggregation systems mainly based on Hsp70 and AAA ATPase Hsp100 chaperones prior to their handover to refolding and degradation systems. Here, we discuss the functional roles that condensate formation/aggregation and disaggregation play in protein quality control to maintain proteostasis and why it matters for understanding health and disease.
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Affiliation(s)
- Verena Kohler
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Claes Andréasson
- Department of Molecular Biosciences, Stockholm University, Stockholm, Sweden
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7
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Xu S, Gierisch ME, Schellhaus AK, Poser I, Alberti S, Salomons FA, Dantuma NP. Cytosolic stress granules relieve the ubiquitin-proteasome system in the nuclear compartment. EMBO J 2023; 42:e111802. [PMID: 36574355 PMCID: PMC9890234 DOI: 10.15252/embj.2022111802] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 11/25/2022] [Accepted: 12/01/2022] [Indexed: 12/28/2022] Open
Abstract
The role of cytosolic stress granules in the integrated stress response has remained largely enigmatic. Here, we studied the functionality of the ubiquitin-proteasome system (UPS) in cells that were unable to form stress granules. Surprisingly, the inability of cells to form cytosolic stress granules had primarily a negative impact on the functionality of the nuclear UPS. While defective ribosome products (DRiPs) accumulated at stress granules in thermally stressed control cells, they localized to nucleoli in stress granule-deficient cells. The nuclear localization of DRiPs was accompanied by redistribution and enhanced degradation of SUMOylated proteins. Depletion of the SUMO-targeted ubiquitin ligase RNF4, which targets SUMOylated misfolded proteins for proteasomal degradation, largely restored the functionality of the UPS in the nuclear compartment in stress granule-deficient cells. Stress granule-deficient cells showed an increase in the formation of mutant ataxin-1 nuclear inclusions when exposed to thermal stress. Our data reveal that stress granules play an important role in the sequestration of cytosolic misfolded proteins, thereby preventing these proteins from accumulating in the nucleus, where they would otherwise infringe nuclear proteostasis.
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Affiliation(s)
- Shanshan Xu
- Department of Cell and Molecular Biology (CMB)Karolinska InstitutetStockholmSweden
| | - Maria E Gierisch
- Department of Cell and Molecular Biology (CMB)Karolinska InstitutetStockholmSweden
| | | | - Ina Poser
- Max Planck Institute of Molecular Cell Biology and GeneticsDresdenGermany
| | - Simon Alberti
- Max Planck Institute of Molecular Cell Biology and GeneticsDresdenGermany
- Biotechnology Center (BIOTEC), Center for Molecular and Cellular Bioengineering (CMCB)Technische Universität DresdenDresdenGermany
| | - Florian A Salomons
- Department of Cell and Molecular Biology (CMB)Karolinska InstitutetStockholmSweden
| | - Nico P Dantuma
- Department of Cell and Molecular Biology (CMB)Karolinska InstitutetStockholmSweden
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8
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Prakash P, Pradhan AK, Sheeba V. Hsp40 overexpression in pacemaker neurons delays circadian dysfunction in a Drosophila model of Huntington's disease. Dis Model Mech 2022; 15:275556. [PMID: 35645202 PMCID: PMC9254228 DOI: 10.1242/dmm.049447] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Accepted: 05/24/2022] [Indexed: 12/13/2022] Open
Abstract
Circadian disturbances are early features of neurodegenerative diseases, including Huntington's disease (HD). Emerging evidence suggests that circadian decline feeds into neurodegenerative symptoms, exacerbating them. Therefore, we asked whether known neurotoxic modifiers can suppress circadian dysfunction. We performed a screen of neurotoxicity-modifier genes to suppress circadian behavioural arrhythmicity in a Drosophila circadian HD model. The molecular chaperones Hsp40 and HSP70 emerged as significant suppressors in the circadian context, with Hsp40 being the more potent mitigator. Upon Hsp40 overexpression in the Drosophila circadian ventrolateral neurons (LNv), the behavioural rescue was associated with neuronal rescue of loss of circadian proteins from small LNv soma. Specifically, there was a restoration of the molecular clock protein Period and its oscillations in young flies and a long-lasting rescue of the output neuropeptide Pigment dispersing factor. Significantly, there was a reduction in the expanded Huntingtin inclusion load, concomitant with the appearance of a spot-like Huntingtin form. Thus, we provide evidence implicating the neuroprotective chaperone Hsp40 in circadian rehabilitation. The involvement of molecular chaperones in circadian maintenance has broader therapeutic implications for neurodegenerative diseases. This article has an associated First Person interview with the first author of the paper. Summary: This study shows, for the first time, a neuroprotective role of chaperone Hsp40 in suppressing circadian dysfunction associated with Huntington's disease in a Drosophila model.
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Affiliation(s)
- Pavitra Prakash
- Evolutionary and Integrative Biology Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India
| | - Arpit Kumar Pradhan
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India
| | - Vasu Sheeba
- Evolutionary and Integrative Biology Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India.,Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India
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9
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Spatial sequestration of misfolded proteins in neurodegenerative diseases. Biochem Soc Trans 2022; 50:759-771. [PMID: 35311889 DOI: 10.1042/bst20210862] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 02/28/2022] [Accepted: 03/02/2022] [Indexed: 12/12/2022]
Abstract
Properly folded, functional proteins are essential for cell health. Cells sustain protein homeostasis, or proteostasis, via protein quality control (PQC) mechanisms. It is currently hypothesized that a breakdown in proteostasis during ageing leads to the accumulation of protein aggregates in the cell and disease. Sequestration of misfolded proteins into PQC compartments represents one branch of the PQC network. In neurodegenerative diseases, certain proteins form abnormal protein deposits. Which PQC compartments house misfolded proteins associated with neurodegenerative diseases is still being investigated. It remains unclear if sequestration of these misfolded proteins is toxic or protective to the cell. Here, we review the current knowledge on various PQC compartments that form in the cell, the kinds of protein aggregates found in neurodegenerative diseases, and what is known about their sequestration. Understanding how protein sequestration occurs can shed light on why aggregates are toxic to the cell and are linked to neurodegenerative diseases like Huntington's, Alzheimer's, and Parkinson's diseases.
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10
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Sönmez A, Mustafa R, Ryll ST, Tuorto F, Wacheul L, Ponti D, Litke C, Hering T, Kojer K, Koch J, Pitzer C, Kirsch J, Neueder A, Kreiner G, Lafontaine DLJ, Orth M, Liss B, Parlato R. Nucleolar stress controls mutant Huntington toxicity and monitors Huntington's disease progression. Cell Death Dis 2021; 12:1139. [PMID: 34880223 PMCID: PMC8655027 DOI: 10.1038/s41419-021-04432-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 11/12/2021] [Accepted: 11/18/2021] [Indexed: 12/26/2022]
Abstract
Transcriptional and cellular-stress surveillance deficits are hallmarks of Huntington's disease (HD), a fatal autosomal-dominant neurodegenerative disorder caused by a pathological expansion of CAG repeats in the Huntingtin (HTT) gene. The nucleolus, a dynamic nuclear biomolecular condensate and the site of ribosomal RNA (rRNA) transcription, is implicated in the cellular stress response and in protein quality control. While the exact pathomechanisms of HD are still unclear, the impact of nucleolar dysfunction on HD pathophysiology in vivo remains elusive. Here we identified aberrant maturation of rRNA and decreased translational rate in association with human mutant Huntingtin (mHTT) expression. The protein nucleophosmin 1 (NPM1), important for nucleolar integrity and rRNA maturation, loses its prominent nucleolar localization. Genetic disruption of nucleolar integrity in vulnerable striatal neurons of the R6/2 HD mouse model decreases the distribution of mHTT in a disperse state in the nucleus, exacerbating motor deficits. We confirmed NPM1 delocalization in the gradually progressing zQ175 knock-in HD mouse model: in the striatum at a presymptomatic stage and in the skeletal muscle at an early symptomatic stage. In Huntington's patient skeletal muscle biopsies, we found a selective redistribution of NPM1, similar to that in the zQ175 model. Taken together, our study demonstrates that nucleolar integrity regulates the formation of mHTT inclusions in vivo, and identifies NPM1 as a novel, readily detectable peripheral histopathological marker of HD progression.
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Affiliation(s)
- Aynur Sönmez
- Institute of Applied Physiology, Ulm University, Ulm, Germany
- RNA Molecular Biology, Fonds de la Recherche Scientifique (F.R.S./FNRS), Université Libre de Bruxelles (ULB), Biopark campus, Gosselies, Belgium
| | - Rasem Mustafa
- Institute of Applied Physiology, Ulm University, Ulm, Germany
- Institute of Anatomy and Cell Biology, Heidelberg University, Heidelberg, Germany
| | - Salome T Ryll
- Institute of Applied Physiology, Ulm University, Ulm, Germany
- Institute of Anatomy and Cell Biology, Heidelberg University, Heidelberg, Germany
| | - Francesca Tuorto
- Division of Biochemistry, Mannheim Institute for Innate Immunoscience (MI3), Medical Faculty Mannheim, Heidelberg University, Mannheim and Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Ludivine Wacheul
- RNA Molecular Biology, Fonds de la Recherche Scientifique (F.R.S./FNRS), Université Libre de Bruxelles (ULB), Biopark campus, Gosselies, Belgium
| | - Donatella Ponti
- Institute of Anatomy and Cell Biology, Heidelberg University, Heidelberg, Germany
- Department of Medical-Surgical Sciences and Biotechnologies, University of Rome "Sapienza", Rome, Italy
| | - Christian Litke
- Institute of Anatomy and Cell Biology, Heidelberg University, Heidelberg, Germany
| | - Tanja Hering
- Department of Neurology, Ulm University, Ulm, Germany
| | - Kerstin Kojer
- Department of Neurology, Ulm University, Ulm, Germany
| | - Jenniver Koch
- Institute of Applied Physiology, Ulm University, Ulm, Germany
| | - Claudia Pitzer
- Interdisciplinary Neurobehavioral Core (INBC), Heidelberg University, Heidelberg, Germany
| | - Joachim Kirsch
- Institute of Anatomy and Cell Biology, Heidelberg University, Heidelberg, Germany
| | | | - Grzegorz Kreiner
- Maj Institute of Pharmacology, Department of Brain Biochemistry, Polish Academy of Sciences, Krakow, Poland
| | - Denis L J Lafontaine
- RNA Molecular Biology, Fonds de la Recherche Scientifique (F.R.S./FNRS), Université Libre de Bruxelles (ULB), Biopark campus, Gosselies, Belgium
| | - Michael Orth
- Department of Neurology, Ulm University, Ulm, Germany
| | - Birgit Liss
- Institute of Applied Physiology, Ulm University, Ulm, Germany
- Linacre & New College, University of Oxford, Oxford, UK
| | - Rosanna Parlato
- Institute of Applied Physiology, Ulm University, Ulm, Germany.
- Institute of Anatomy and Cell Biology, Heidelberg University, Heidelberg, Germany.
- Division for Neurodegenerative Diseases, Department of Neurology, Mannheim Center for Translational Neuroscience, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.
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11
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Kumar AV, Lapierre LR. Location, location, location: subcellular protein partitioning in proteostasis and aging. Biophys Rev 2021; 13:931-941. [PMID: 35047088 PMCID: PMC8724496 DOI: 10.1007/s12551-021-00890-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Accepted: 11/01/2021] [Indexed: 12/25/2022] Open
Abstract
Somatic maintenance and cell survival rely on proper protein homeostasis to ensure reliable functions across the cell and to prevent proteome collapse. Maintaining protein folding and solubility is central to proteostasis and is coordinated by protein synthesis, chaperoning, and degradation capacities. An emerging aspect that influences proteostasis is the dynamic protein partitioning across different subcellular structures and compartments. Here, we review recent literature related to nucleocytoplasmic partitioning of proteins, nuclear and cytoplasmic quality control mechanisms, and their impact on the development of age-related diseases. We also highlight new points of entry to modulate spatially-regulated proteostatic mechanisms to delay aging.
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Affiliation(s)
- Anita V. Kumar
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI 02912 USA
| | - Louis R. Lapierre
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI 02912 USA
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12
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It's not just a phase; ubiquitination in cytosolic protein quality control. Biochem Soc Trans 2021; 49:365-377. [PMID: 33634825 PMCID: PMC7924994 DOI: 10.1042/bst20200694] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 02/01/2021] [Accepted: 02/02/2021] [Indexed: 02/04/2023]
Abstract
The accumulation of misfolded proteins is associated with numerous degenerative conditions, cancers and genetic diseases. These pathological imbalances in protein homeostasis (termed proteostasis), result from the improper triage and disposal of damaged and defective proteins from the cell. The ubiquitin-proteasome system is a key pathway for the molecular control of misfolded cytosolic proteins, co-opting a cascade of ubiquitin ligases to direct terminally damaged proteins to the proteasome via modification with chains of the small protein, ubiquitin. Despite the evidence for ubiquitination in this critical pathway, the precise complement of ubiquitin ligases and deubiquitinases that modulate this process remains under investigation. Whilst chaperones act as the first line of defence against protein misfolding, the ubiquitination machinery has a pivotal role in targeting terminally defunct cytosolic proteins for destruction. Recent work points to a complex assemblage of chaperones, ubiquitination machinery and subcellular quarantine as components of the cellular arsenal against proteinopathies. In this review, we examine the contribution of these pathways and cellular compartments to the maintenance of the cytosolic proteome. Here we will particularly focus on the ubiquitin code and the critical enzymes which regulate misfolded proteins in the cytosol, the molecular point of origin for many neurodegenerative and genetic diseases.
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13
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Lin CN, Tsai YC, Hsu CC, Liang YL, Wu YY, Kang CY, Lin CH, Hsu PH, Lee GB, Hsu KF. An aptamer interacting with heat shock protein 70 shows therapeutic effects and prognostic ability in serous ovarian cancer. MOLECULAR THERAPY-NUCLEIC ACIDS 2021; 23:757-768. [PMID: 33614227 PMCID: PMC7868721 DOI: 10.1016/j.omtn.2020.12.025] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Accepted: 12/31/2020] [Indexed: 12/12/2022]
Abstract
Ovarian cancer (OvCa) is the most lethal gynecologic malignancy owing to its high chemoresistance and late diagnosis, which lead to a poor prognosis. Hence, developing new therapeutic modalities is important for OvCa patient treatment. Our previous results indicated that a novel aptamer, Tx-01, can specifically recognize serous carcinoma cells and tissues. Here, we aim to clarify the clinical role and possible molecular mechanisms of Tx-01 in OvCa. Immunostaining and statistical analysis were performed to detect the interaction of Tx-01 and heat shock protein 70/Notch1 intracellular domain (HSP70/NICD) in OvCa. The in vitro and in vivo experiments were carried out to demonstrate the potential mechanisms of Tx-01. Results show that Tx-01 reduced serous OvCa OVCAR3 cell migration and invasion and inhibited HSP70 nuclear translocation by interrupting the intracellular HSP70/NICD interaction. Furthermore, Tx-01 suppressed serous-type OVCAR3 cell tumor growth in vivo. Tx-01 acts as a prognostic factor through its interaction with membrane-bound HSP70 (mHSP70 that locates on the cell surface without direct interaction to NICD) on ascitic circulating tumor cells (CTCs) and is reported to be involved in natural killer (NK) cell recognition and activation. Our data demonstrated that Tx-01 interacted with HSP70 and showed therapeutic and prognostic effects in serous OvCa. Tx-01 might be a potential inhibitor for use in serous OvCa treatment.
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Affiliation(s)
- Chang-Ni Lin
- Department of Obstetrics and Gynecology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Yi-Cheng Tsai
- Department of Power Mechanical Engineering, National Tsing Hua University, Hsinchu, Taiwan
| | - Ching-Cheng Hsu
- Department of Radiation Oncology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX, USA
| | - Yu-Ling Liang
- Department of Obstetrics and Gynecology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Yi-Ying Wu
- Graduate Institute of Clinical Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Chieh-Yi Kang
- Department of Obstetrics and Gynecology, Chi-Mei Medical Center, Tainan, Taiwan
| | - Chun-Hong Lin
- Department of Obstetrics and Gynecology, Chi-Mei Medical Center, Tainan, Taiwan
| | - Pang-Hung Hsu
- Department of Bioscience and Biotechnology, National Taiwan Ocean University, Keelung, Taiwan.,Institute of Biochemistry and Molecular Biology, National Yang Ming University, Taipei, Taiwan
| | - Gwo-Bin Lee
- Department of Power Mechanical Engineering, National Tsing Hua University, Hsinchu, Taiwan
| | - Keng-Fu Hsu
- Department of Obstetrics and Gynecology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
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14
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Kao CH, Ryu SW, Kim MJ, Wen X, Wimalarathne O, Paull TT. Growth-Regulated Hsp70 Phosphorylation Regulates Stress Responses and Prion Maintenance. Mol Cell Biol 2020; 40:e00628-19. [PMID: 32205407 PMCID: PMC7261718 DOI: 10.1128/mcb.00628-19] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Revised: 02/05/2020] [Accepted: 03/18/2020] [Indexed: 11/20/2022] Open
Abstract
Maintenance of protein homeostasis in eukaryotes under normal growth and stress conditions requires the functions of Hsp70 chaperones and associated cochaperones. Here, we investigate an evolutionarily conserved serine phosphorylation that occurs at the site of communication between the nucleotide-binding and substrate-binding domains of Hsp70. Ser151 phosphorylation in yeast Hsp70 (Ssa1) is promoted by cyclin-dependent kinase (Cdk1) during normal growth. Phosphomimetic substitutions at this site (S151D) dramatically downregulate heat shock responses, a result conserved with HSC70 S153 in human cells. Phosphomimetic forms of Ssa1 also fail to relocalize in response to starvation conditions, do not associate in vivo with Hsp40 cochaperones Ydj1 and Sis1, and do not catalyze refolding of denatured proteins in vitro in cooperation with Ydj1 and Hsp104. Despite these negative effects on HSC70/HSP70 function, the S151D phosphomimetic allele promotes survival of heavy metal exposure and suppresses the Sup35-dependent [PSI+ ] prion phenotype, consistent with proposed roles for Ssa1 and Hsp104 in generating self-nucleating seeds of misfolded proteins. Taken together, these results suggest that Cdk1 can downregulate Hsp70 function through phosphorylation of this site, with potential costs to overall chaperone efficiency but also advantages with respect to reduction of metal-induced and prion-dependent protein aggregate production.
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Affiliation(s)
- Chung-Hsuan Kao
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas, USA
| | - Seung W Ryu
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas, USA
| | - Min J Kim
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas, USA
| | - Xuemei Wen
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas, USA
| | - Oshadi Wimalarathne
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas, USA
| | - Tanya T Paull
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas, USA
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15
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Frottin F, Schueder F, Tiwary S, Gupta R, Körner R, Schlichthaerle T, Cox J, Jungmann R, Hartl FU, Hipp MS. The nucleolus functions as a phase-separated protein quality control compartment. Science 2019; 365:342-347. [PMID: 31296649 DOI: 10.1126/science.aaw9157] [Citation(s) in RCA: 288] [Impact Index Per Article: 57.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 05/23/2019] [Accepted: 06/27/2019] [Indexed: 12/24/2022]
Abstract
The nuclear proteome is rich in stress-sensitive proteins, which suggests that effective protein quality control mechanisms are in place to ensure conformational maintenance. We investigated the role of the nucleolus in this process. In mammalian tissue culture cells under stress conditions, misfolded proteins entered the granular component (GC) phase of the nucleolus. Transient associations with nucleolar proteins such as NPM1 conferred low mobility to misfolded proteins within the liquid-like GC phase, avoiding irreversible aggregation. Refolding and extraction of proteins from the nucleolus during recovery from stress was Hsp70-dependent. The capacity of the nucleolus to store misfolded proteins was limited, and prolonged stress led to a transition of the nucleolar matrix from liquid-like to solid, with loss of reversibility and dysfunction in quality control. Thus, we suggest that the nucleolus has chaperone-like properties and can promote nuclear protein maintenance under stress.
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Affiliation(s)
- F Frottin
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, D-82152 Martinsried, Germany
| | - F Schueder
- Research Group "Molecular Imaging and Bionanotechnology," Max Planck Institute of Biochemistry, D-82152 Martinsried, Germany.,Faculty of Physics and Center for Nanoscience, Ludwig Maximilian University, D-80539 Munich, Germany
| | - S Tiwary
- Research Group "Computational Systems Biochemistry," Max Planck Institute of Biochemistry, D-82152 Martinsried, Germany
| | - R Gupta
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, D-82152 Martinsried, Germany
| | - R Körner
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, D-82152 Martinsried, Germany
| | - T Schlichthaerle
- Research Group "Molecular Imaging and Bionanotechnology," Max Planck Institute of Biochemistry, D-82152 Martinsried, Germany.,Faculty of Physics and Center for Nanoscience, Ludwig Maximilian University, D-80539 Munich, Germany
| | - J Cox
- Research Group "Computational Systems Biochemistry," Max Planck Institute of Biochemistry, D-82152 Martinsried, Germany
| | - R Jungmann
- Research Group "Molecular Imaging and Bionanotechnology," Max Planck Institute of Biochemistry, D-82152 Martinsried, Germany. .,Faculty of Physics and Center for Nanoscience, Ludwig Maximilian University, D-80539 Munich, Germany
| | - F U Hartl
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, D-82152 Martinsried, Germany. .,Munich Cluster for Systems Neurology (SyNergy), D-80336 Munich, Germany
| | - M S Hipp
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, D-82152 Martinsried, Germany. .,Munich Cluster for Systems Neurology (SyNergy), D-80336 Munich, Germany
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16
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Mediani L, Guillén-Boixet J, Vinet J, Franzmann TM, Bigi I, Mateju D, Carrà AD, Morelli FF, Tiago T, Poser I, Alberti S, Carra S. Defective ribosomal products challenge nuclear function by impairing nuclear condensate dynamics and immobilizing ubiquitin. EMBO J 2019; 38:e101341. [PMID: 31271238 PMCID: PMC6669919 DOI: 10.15252/embj.2018101341] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 06/05/2019] [Accepted: 06/07/2019] [Indexed: 12/25/2022] Open
Abstract
Nuclear protein aggregation has been linked to genome instability and disease. The main source of aggregation‐prone proteins in cells is defective ribosomal products (DRiPs), which are generated by translating ribosomes in the cytoplasm. Here, we report that DRiPs rapidly diffuse into the nucleus and accumulate in nucleoli and PML bodies, two membraneless organelles formed by liquid–liquid phase separation. We show that nucleoli and PML bodies act as dynamic overflow compartments that recruit protein quality control factors and store DRiPs for later clearance. Whereas nucleoli serve as constitutive overflow compartments, PML bodies are stress‐inducible overflow compartments for DRiPs. If DRiPs are not properly cleared by chaperones and proteasomes due to proteostasis impairment, nucleoli undergo amyloidogenesis and PML bodies solidify. Solid PML bodies immobilize 20S proteasomes and limit the recycling of free ubiquitin. Ubiquitin depletion, in turn, compromises the formation of DNA repair compartments at fragile chromosomal sites, ultimately threatening cell survival.
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Affiliation(s)
- Laura Mediani
- Centre for Neuroscience and Nanotechnology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | | | - Jonathan Vinet
- Centre for Neuroscience and Nanotechnology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy.,Genomic and post-Genomic Center, IRCCS Mondino Foundation, Pavia, Italy
| | - Titus M Franzmann
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Ilaria Bigi
- Centre for Neuroscience and Nanotechnology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Daniel Mateju
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Arianna D Carrà
- Centre for Neuroscience and Nanotechnology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Federica F Morelli
- Centre for Neuroscience and Nanotechnology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Tatiana Tiago
- Centre for Neuroscience and Nanotechnology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Ina Poser
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Simon Alberti
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany.,Technische Universität Dresden, Center for Molecular and Cellular Bioengineering (CMCB), Biotechnology Center (BIOTEC), Dresden, Germany
| | - Serena Carra
- Centre for Neuroscience and Nanotechnology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy
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17
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Kami K, Ohira T, Oishi Y, Nakajima T, Goto K, Ohira Y. Role of 72-kDa Heat Shock Protein in Heat-stimulated Regeneration of Injured Muscle in Rat. J Histochem Cytochem 2019; 67:791-799. [PMID: 31233366 DOI: 10.1369/0022155419859861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The regeneration of injured muscles is facilitated by intermittent heat stress. The 72-kDa heat shock protein (HSP72), the level of which is increased by heat stress, is likely involved in this effect, but the precise mechanism remains unclear. This study was conducted to investigate the localization and role(s) of HSP72 in the regenerating muscles in heat-stressed rats using immunohistochemistry. Heat stress was applied by immersion of the rat lower body into hot water (42C, 30 min, every other day) following injection of bupivacaine into the soleus muscles. After 1 week, we found that HSP72 was expressed at high levels not only in the surviving myofibers but also in the blood vessels of the regenerating muscles in heated rats. In addition, leukocytes, possibly granulocytes, expressing cluster of differentiation 43 within the blood capillaries surrounding the regenerating myofibers also highly expressed HSP72. In contrast, marked expression of HSP72 was not observed in the intact or regenerating muscles without heat stress. These results suggest that heat-stress-induced HSP72 within the myofibers, blood vessels, and circulating leukocytes may play important roles in enhancing regeneration of injured muscles by heat stress. Our findings would be useful to investigate cell-specific role(s) of HSP72 during skeletal muscle regeneration.
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Affiliation(s)
- Katsuya Kami
- Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Takashi Ohira
- Division of Aerospace Medicine, Department of Cell Physiology, The Jikei University School of Medicine, Tokyo, Japan.,Research Center for Space and Medical Sciences, Doshisha University, Kyoto, Japan
| | - Yasuharu Oishi
- Faculty of Education, Kumamoto University, Kumamoto, Japan.,Research Center for Space and Medical Sciences, Doshisha University, Kyoto, Japan
| | - Takayuki Nakajima
- Department of Clinical Medicine, The Jikei University Hospital, Tokyo, Japan
| | - Katsumasa Goto
- Department of Physiology, Graduate School of Health Sciences, Toyohashi SOZO University, Aichi, Japan.,Research Center for Space and Medical Sciences, Doshisha University, Kyoto, Japan
| | - Yoshinobu Ohira
- Graduate School of Medicine, Osaka University, Osaka, Japan.,Research Center for Space and Medical Sciences, Doshisha University, Kyoto, Japan
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18
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Azkanaz M, Rodríguez López A, de Boer B, Huiting W, Angrand PO, Vellenga E, Kampinga HH, Bergink S, Martens JH, Schuringa JJ, van den Boom V. Protein quality control in the nucleolus safeguards recovery of epigenetic regulators after heat shock. eLife 2019; 8:45205. [PMID: 31199242 PMCID: PMC6570483 DOI: 10.7554/elife.45205] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 05/21/2019] [Indexed: 12/19/2022] Open
Abstract
Maintenance of epigenetic modifiers is of utmost importance to preserve the epigenome and consequently appropriate cellular functioning. Here, we analyzed Polycomb group protein (PcG) complex integrity in response to heat shock (HS). Upon HS, various Polycomb Repressive Complex (PRC)1 and PRC2 subunits, including CBX proteins, but also other chromatin regulators, are found to accumulate in the nucleolus. In parallel, binding of PRC1/2 to target genes is strongly reduced, coinciding with a dramatic loss of H2AK119ub and H3K27me3 marks. Nucleolar-accumulated CBX proteins are immobile, but remarkably both CBX protein accumulation and loss of PRC1/2 epigenetic marks are reversible. This post-heat shock recovery of pan-nuclear CBX protein localization and reinstallation of epigenetic marks is HSP70 dependent. Our findings demonstrate that the nucleolus is an essential protein quality control center, which is indispensable for recovery of epigenetic regulators and maintenance of the epigenome after heat shock.
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Affiliation(s)
- Maria Azkanaz
- Department of Experimental Hematology, Cancer Research Center Groningen, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | - Aida Rodríguez López
- Department of Experimental Hematology, Cancer Research Center Groningen, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | - Bauke de Boer
- Department of Experimental Hematology, Cancer Research Center Groningen, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | - Wouter Huiting
- Department of Biomedical Sciences of Cells and Systems, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | | | - Edo Vellenga
- Department of Experimental Hematology, Cancer Research Center Groningen, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | - Harm H Kampinga
- Department of Biomedical Sciences of Cells and Systems, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | - Steven Bergink
- Department of Biomedical Sciences of Cells and Systems, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | - Joost Ha Martens
- Department of Molecular Biology, Faculty of Science and Medicine, Radboud Institute for Molecular Life Sciences, Radboud University Nijmegen, Nijmegen, Netherlands
| | - Jan Jacob Schuringa
- Department of Experimental Hematology, Cancer Research Center Groningen, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | - Vincent van den Boom
- Department of Experimental Hematology, Cancer Research Center Groningen, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
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19
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Hsp70 interactions with membrane lipids regulate cellular functions in health and disease. Prog Lipid Res 2019; 74:18-30. [PMID: 30710597 DOI: 10.1016/j.plipres.2019.01.004] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Revised: 01/18/2019] [Accepted: 01/28/2019] [Indexed: 02/07/2023]
Abstract
Beyond guarding the cellular proteome the major stress inducible heat shock protein Hsp70 has been shown to interact with lipids. Non-cytosolic Hsp70 stabilizes membranes during stress challenges and, in pathophysiological states, facilitates endocytosis, counteracts apoptotic mechanisms, sustains survival pathways or represents a signal that can be recognized by the immune system. Disease-coupled lipid-associated functions of Hsp70 may be targeted via distinct subcellular localizations of Hsp70 itself or its specific interacting lipids. With a special focus on interacting lipids, here we discuss localization-dependent roles of the membrane-bound Hsp70 in the context of its therapeutic potential, particularly in cancer and neurodegenerative diseases.
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20
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The nucleolar transcriptome regulates Piwi shuttling between the nucleolus and the nucleoplasm. Chromosome Res 2018; 27:141-152. [DOI: 10.1007/s10577-018-9595-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Revised: 11/25/2018] [Accepted: 11/29/2018] [Indexed: 01/25/2023]
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21
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Galiè M, Costanzo M, Nodari A, Boschi F, Calderan L, Mannucci S, Covi V, Tabaracci G, Malatesta M. Mild ozonisation activates antioxidant cell response by the Keap1/Nrf2 dependent pathway. Free Radic Biol Med 2018; 124:114-121. [PMID: 29864481 DOI: 10.1016/j.freeradbiomed.2018.05.093] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 05/30/2018] [Accepted: 05/31/2018] [Indexed: 12/13/2022]
Abstract
Treatment with low-dose ozone is successfully exploited as an adjuvant therapy in the treatment of several disorders. Although the list of medical applications of ozone therapy is increasing, molecular mechanisms underlying its beneficial effects are still partially known. Clinical and experimental evidence suggests that the therapeutic effects of ozone treatment may rely on its capability to mount a beneficial antioxidant response through activation of the nuclear factor erythroid-derived-like 2 (Nrf2) pathway. However, a conclusive mechanistic demonstration is still lacking. Here, we bridge this gap of knowledge by providing evidence that treatment with a low concentration of ozone in cultured cells promotes nuclear translocation of Nrf2 at the chromatin sites of active transcription and increases the expression of antioxidant response element (ARE)-driven genes. Importantly, we show that ozone-induced ARE activation can be reverted by the ectopic expression of the Nrf2 specific inhibitor Kelch-like ECH associated protein (Keap1), thus proving the role of the Nrf2 pathway in the antioxidant response induced by mild ozonisation.
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Affiliation(s)
- Mirco Galiè
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Strada Le Grazie 8, I-37134 Verona, Italy
| | - Manuela Costanzo
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Strada Le Grazie 8, I-37134 Verona, Italy
| | - Alice Nodari
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Strada Le Grazie 8, I-37134 Verona, Italy
| | - Federico Boschi
- Department of Computer Science, University of Verona, Strada Le Grazie 15, I-37134 Verona, Italy
| | - Laura Calderan
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Strada Le Grazie 8, I-37134 Verona, Italy
| | - Silvia Mannucci
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Strada Le Grazie 8, I-37134 Verona, Italy
| | - Viviana Covi
- San Rocco Clinic, Via Monsignor G. V. Moreni 95, 25018 Montichiari, BS, Italy
| | - Gabriele Tabaracci
- San Rocco Clinic, Via Monsignor G. V. Moreni 95, 25018 Montichiari, BS, Italy
| | - Manuela Malatesta
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Strada Le Grazie 8, I-37134 Verona, Italy.
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22
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Peksel B, Gombos I, Péter M, Vigh L, Tiszlavicz Á, Brameshuber M, Balogh G, Schütz GJ, Horváth I, Vigh L, Török Z. Mild heat induces a distinct "eustress" response in Chinese Hamster Ovary cells but does not induce heat shock protein synthesis. Sci Rep 2017; 7:15643. [PMID: 29142280 PMCID: PMC5688065 DOI: 10.1038/s41598-017-15821-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Accepted: 11/02/2017] [Indexed: 11/16/2022] Open
Abstract
The current research on cellular heat stress management focuses on the roles of heat shock proteins (HSPs) and the proteostasis network under severe stress conditions. The mild, fever-type stress and the maintenance of membrane homeostasis are less well understood. Herein, we characterized the acute effect of mild, fever-range heat shock on membrane organization, and HSP synthesis and localization in two mammalian cell lines, to delineate the role of membranes in the sensing and adaptation to heat. A multidisciplinary approach combining ultrasensitive fluorescence microscopy and lipidomics revealed the molecular details of novel cellular “eustress”, when cells adapt to mild heat by maintaining membrane homeostasis, activating lipid remodeling, and redistributing chaperone proteins. Notably, this leads to acquired thermotolerance in the complete absence of the induction of HSPs. At higher temperatures, additional defense mechanisms are activated, including elevated expression of molecular chaperones, contributing to an extended stress memory and acquired thermotolerance.
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Affiliation(s)
- Begüm Peksel
- Institute of Biochemistry, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, H-6726, Hungary
| | - Imre Gombos
- Institute of Biochemistry, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, H-6726, Hungary
| | - Mária Péter
- Institute of Biochemistry, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, H-6726, Hungary
| | - László Vigh
- Institute of Biochemistry, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, H-6726, Hungary
| | - Ádám Tiszlavicz
- Institute of Biochemistry, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, H-6726, Hungary
| | - Mario Brameshuber
- Institute of Applied Physics - Biophysics, TU Wien, 1040, Vienna, Austria
| | - Gábor Balogh
- Institute of Biochemistry, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, H-6726, Hungary
| | - Gerhard J Schütz
- Institute of Applied Physics - Biophysics, TU Wien, 1040, Vienna, Austria
| | - Ibolya Horváth
- Institute of Biochemistry, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, H-6726, Hungary
| | - László Vigh
- Institute of Biochemistry, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, H-6726, Hungary
| | - Zsolt Török
- Institute of Biochemistry, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, H-6726, Hungary.
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23
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Seo JH, Park JH, Lee EJ, Vo TTL, Choi H, Kim JY, Jang JK, Wee HJ, Lee HS, Jang SH, Park ZY, Jeong J, Lee KJ, Seok SH, Park JY, Lee BJ, Lee MN, Oh GT, Kim KW. ARD1-mediated Hsp70 acetylation balances stress-induced protein refolding and degradation. Nat Commun 2016; 7:12882. [PMID: 27708256 PMCID: PMC5059642 DOI: 10.1038/ncomms12882] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2016] [Accepted: 08/10/2016] [Indexed: 01/04/2023] Open
Abstract
Heat shock protein (Hsp)70 is a molecular chaperone that maintains protein homoeostasis during cellular stress through two opposing mechanisms: protein refolding and degradation. However, the mechanisms by which Hsp70 balances these opposing functions under stress conditions remain unknown. Here, we demonstrate that Hsp70 preferentially facilitates protein refolding after stress, gradually switching to protein degradation via a mechanism dependent on ARD1-mediated Hsp70 acetylation. During the early stress response, Hsp70 is immediately acetylated by ARD1 at K77, and the acetylated Hsp70 binds to the co-chaperone Hop to allow protein refolding. Thereafter, Hsp70 is deacetylated and binds to the ubiquitin ligase protein CHIP to complete protein degradation during later stages. This switch is required for the maintenance of protein homoeostasis and ultimately rescues cells from stress-induced cell death in vitro and in vivo. Therefore, ARD1-mediated Hsp70 acetylation is a regulatory mechanism that temporally balances protein refolding/degradation in response to stress. The chaperone Hsp70 has a dual role, promoting both protein refolding and protein degradation. Seo and Park et al. show that Hsp70 acetylation enhances protein refolding after stress, and that subsequent deacetylation progressively promotes ubiquitin ligase binding and protein degradation.
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Affiliation(s)
- Ji Hae Seo
- SNU-Harvard NeuroVascular Protection Research Center, College of Pharmacy, Seoul National University, Seoul 08826, Korea
| | - Ji-Hyeon Park
- SNU-Harvard NeuroVascular Protection Research Center, College of Pharmacy, Seoul National University, Seoul 08826, Korea
| | - Eun Ji Lee
- SNU-Harvard NeuroVascular Protection Research Center, College of Pharmacy, Seoul National University, Seoul 08826, Korea
| | - Tam Thuy Lu Vo
- SNU-Harvard NeuroVascular Protection Research Center, College of Pharmacy, Seoul National University, Seoul 08826, Korea
| | - Hoon Choi
- SNU-Harvard NeuroVascular Protection Research Center, College of Pharmacy, Seoul National University, Seoul 08826, Korea
| | - Jun Yong Kim
- Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 08826, Korea
| | - Jae Kyung Jang
- SNU-Harvard NeuroVascular Protection Research Center, College of Pharmacy, Seoul National University, Seoul 08826, Korea
| | - Hee-Jun Wee
- SNU-Harvard NeuroVascular Protection Research Center, College of Pharmacy, Seoul National University, Seoul 08826, Korea
| | - Hye Shin Lee
- SNU-Harvard NeuroVascular Protection Research Center, College of Pharmacy, Seoul National University, Seoul 08826, Korea
| | - Se Hwan Jang
- School of Life Sciences, Gwangju Institute of Science &Technology, Gwangju 61005, Korea
| | - Zee Yong Park
- School of Life Sciences, Gwangju Institute of Science &Technology, Gwangju 61005, Korea
| | - Jaeho Jeong
- Graduate School of Pharmaceutical Sciences, College of Pharmacy, Ewha Womans University, Seoul 03760, Korea
| | - Kong-Joo Lee
- Graduate School of Pharmaceutical Sciences, College of Pharmacy, Ewha Womans University, Seoul 03760, Korea
| | - Seung-Hyeon Seok
- The Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 08826, Korea
| | - Jin Young Park
- The Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 08826, Korea
| | - Bong Jin Lee
- The Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 08826, Korea
| | - Mi-Ni Lee
- Department of Life Sciences, Ewha Womans University, Seoul 03760, Korea
| | - Goo Taeg Oh
- Department of Life Sciences, Ewha Womans University, Seoul 03760, Korea
| | - Kyu-Won Kim
- SNU-Harvard NeuroVascular Protection Research Center, College of Pharmacy, Seoul National University, Seoul 08826, Korea.,Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 08826, Korea.,Crop Biotechnology Institute, GreenBio Science and Technology, Seoul National University, Pyeongchang 25354, Korea
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Roles of Cross-Membrane Transport and Signaling in the Maintenance of Cellular Homeostasis. Cell Mol Bioeng 2016; 9:234-246. [PMID: 27335609 PMCID: PMC4893050 DOI: 10.1007/s12195-016-0439-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 04/19/2016] [Indexed: 11/03/2022] Open
Abstract
Organelles allow specialized functions within cells to be localized, contained and independently regulated. This separation is oftentimes achieved by selectively permeable membranes, which enable control of molecular transport, signaling between compartments and containment of stress-inducing factors. Here we consider the role of a number of membrane systems within the cell: the plasma membrane, that of the endoplasmic reticulum, and then focusing on the nucleus, depository for chromatin and regulatory centre of the cell. Nuclear pores allow shuttling of ions, metabolites, proteins and mRNA to and from the nucleus. The activity of transcription factors and signaling molecules is also modulated by translocation across the nuclear envelope. Many of these processes require ‘active transportation’ against a concentration gradient and may be regulated by the nuclear pores, Ran-GTP activity and the nuclear lamina. Cells must respond to a combination of biochemical and physical inputs and we discuss too how mechanical signals are carried from outside the cell into the nucleus through integrins, the cytoskeleton and the ‘linker of nucleo- and cyto-skeletal’ (LINC) complex which spans the nuclear envelope. Regulation and response to signals and stresses, both internal and external, allow cells to maintain homeostasis within functional tissue.
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25
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Kampinga HH, Bergink S. Heat shock proteins as potential targets for protective strategies in neurodegeneration. Lancet Neurol 2016; 15:748-759. [PMID: 27106072 DOI: 10.1016/s1474-4422(16)00099-5] [Citation(s) in RCA: 101] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Revised: 01/09/2016] [Accepted: 02/24/2016] [Indexed: 01/08/2023]
Abstract
Protein aggregates are hallmarks of nearly all age-related neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, and several polyglutamine diseases such as Huntington's disease and different forms of spinocerebellar ataxias (SCA; SCA1-3, SCA6, and SCA7). The collapse of cellular protein homoeostasis can be both a cause and a consequence of this protein aggregation. Boosting components of the cellular protein quality control system has been widely investigated as a strategy to counteract protein aggregates or their toxic consequences. Heat shock proteins (HSPs) play a central part in regulating protein quality control and contribute to protein aggregation and disaggregation. Therefore, HSPs are viable targets for the development of drugs aimed at reducing pathogenic protein aggregates that are thought to contribute to the development of so many neurodegenerative disorders.
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Affiliation(s)
- Harm H Kampinga
- Department of Cell Biology, University Medical Center Groningen, Rijksuniversiteit Groningen, Groningen, Netherlands.
| | - Steven Bergink
- Department of Cell Biology, University Medical Center Groningen, Rijksuniversiteit Groningen, Groningen, Netherlands
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26
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Yerbury JJ, Ooi L, Dillin A, Saunders DN, Hatters DM, Beart PM, Cashman NR, Wilson MR, Ecroyd H. Walking the tightrope: proteostasis and neurodegenerative disease. J Neurochem 2016; 137:489-505. [DOI: 10.1111/jnc.13575] [Citation(s) in RCA: 146] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Revised: 02/03/2016] [Accepted: 02/04/2016] [Indexed: 02/06/2023]
Affiliation(s)
- Justin J. Yerbury
- Proteostasis and Disease Research Centre; School of Biological Sciences; Faculty of Science, Medicine and Health; University of Wollongong; Wollongong New South Wales Australia
- Illawarra Health and Medical Research Institute; Wollongong; New South Wales Australia
| | - Lezanne Ooi
- Proteostasis and Disease Research Centre; School of Biological Sciences; Faculty of Science, Medicine and Health; University of Wollongong; Wollongong New South Wales Australia
- Illawarra Health and Medical Research Institute; Wollongong; New South Wales Australia
| | - Andrew Dillin
- Department of Molecular and Cell Biology; Li Ka Shing Center for Biomedical and Health Sciences; The University of California; California USA
- Howard Hughes Medical Institute; The University of California; Berkeley California USA
| | - Darren N. Saunders
- School of Medical Sciences; Faculty of Medicine; University of New South Wales; Randwick New South Wales Australia
- The Kinghorn Cancer Centre; Garvan Institute of Medical Research; Darlinghurst New South Wales Australia
| | - Danny M. Hatters
- Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute; University of Melbourne; Parkville Victoria Australia
| | - Philip M. Beart
- Florey Institute of Neuroscience and Mental Health; University of Melbourne; Parkville Victoria Australia
| | - Neil R. Cashman
- Department of Medicine (Neurology); University of British Columbia and Vancouver Coastal Health Research Institute; Brain Research Centre; University of British Columbia; Vancouver British Columbia Canada
| | - Mark R. Wilson
- Proteostasis and Disease Research Centre; School of Biological Sciences; Faculty of Science, Medicine and Health; University of Wollongong; Wollongong New South Wales Australia
- Illawarra Health and Medical Research Institute; Wollongong; New South Wales Australia
| | - Heath Ecroyd
- Proteostasis and Disease Research Centre; School of Biological Sciences; Faculty of Science, Medicine and Health; University of Wollongong; Wollongong New South Wales Australia
- Illawarra Health and Medical Research Institute; Wollongong; New South Wales Australia
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27
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Zoroquiain P, Faingold D, Algahmdi S, Vila N, Logan P, Sanft DM, Toledo Dias AB, Aldrees S, Bravo-Filho V, Burnier J, Burnier MN. Analysis of HSP90 Expression Is Valuable in the Differential Diagnosis of Ocular Surface Squamous Lesions. Am J Clin Pathol 2016; 145:385-92. [PMID: 27124921 DOI: 10.1093/ajcp/aqw007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
OBJECTIVES The aim of this study was to evaluate heat shock protein 90 (HSP90) expression in squamous lesions (SLs) and to assess its diagnostic value for different lesions within the SL spectrum. METHODS A total of 70 conjunctival SLs, including 19 papillomas, 22 cases of conjunctival intraepithelial neoplasia (ConINs) I, 11 cases of ConIN II, six cases of ConIN III, and 12 squamous carcinomas (sqCAs), were evaluated using the German immunoreactive score against HSP90. RESULTS Cytoplasmic HSP90 expression differed between low- and high-grade lesions (P < .001). Among high-grade lesions, the nuclear HSP90 score was higher in the ConIN III-sqCA group than in the ConIN II group (P = .0162). A percentage of total thickness staining of less than 73% differentiated between ConIN III and sqCA. CONCLUSIONS The expression of HSP90 is particularly useful to differentiate low-grade from high-grade lesions of the conjunctiva. HSP90 may play an important role in the malignant transformation of SLs and could be a new target for therapy.
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Affiliation(s)
- Pablo Zoroquiain
- From the Henry C. Witelson Ocular Pathology Laboratory, McGill University, Montreal, Canada; Pathology Department, School of Medicine, Pontifical Catholic University of Chile, Santiago.
| | - Dana Faingold
- From the Henry C. Witelson Ocular Pathology Laboratory, McGill University, Montreal, Canada
| | - Sarah Algahmdi
- From the Henry C. Witelson Ocular Pathology Laboratory, McGill University, Montreal, Canada
| | - Natalia Vila
- From the Henry C. Witelson Ocular Pathology Laboratory, McGill University, Montreal, Canada
| | - Patrick Logan
- From the Henry C. Witelson Ocular Pathology Laboratory, McGill University, Montreal, Canada
| | - Debra-Meghan Sanft
- From the Henry C. Witelson Ocular Pathology Laboratory, McGill University, Montreal, Canada
| | | | - Sultan Aldrees
- From the Henry C. Witelson Ocular Pathology Laboratory, McGill University, Montreal, Canada
| | - Vasco Bravo-Filho
- From the Henry C. Witelson Ocular Pathology Laboratory, McGill University, Montreal, Canada
| | - Julia Burnier
- From the Henry C. Witelson Ocular Pathology Laboratory, McGill University, Montreal, Canada
| | - Miguel N Burnier
- From the Henry C. Witelson Ocular Pathology Laboratory, McGill University, Montreal, Canada
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28
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Zhang Z, Li B, Meng X, Yao S, Jin L, Yang J, Wang J, Zhang H, Zhang Z, Cai D, Zhang Y, Ning G. Berberine prevents progression from hepatic steatosis to steatohepatitis and fibrosis by reducing endoplasmic reticulum stress. Sci Rep 2016; 6:20848. [PMID: 26857750 PMCID: PMC4746620 DOI: 10.1038/srep20848] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 01/12/2016] [Indexed: 02/08/2023] Open
Abstract
The histological spectrum of nonalcoholic fatty liver diseases (NAFLD) ranges from hepatic steatosis to steatohepatitis and fibrosis. Berberine (BBR) is known for its therapeutic effect on obesity, hyperglycaemia and dyslipidaemia; however, its effect on NAFLD has yet to be thoroughly explored. Db/db mice and methionine-choline-deficient diet-fed mice were administered BBR via gavage. We found that BBR-treated mice were more resistant to steatosis in the liver than vehicle-treated mice and that BBR significantly reduced hepatic inflammation, fibrosis and lipid peroxides. The beneficial effect of BBR was associated with suppressing endoplasmic reticulum (ER) stress. Additionally, BBR decreased the free fatty acid-induced lipid accumulation and tunicamycin-induced ER stress in primary hepatocytes and hepatocyte cell lines. We demonstrated that BBR exhibited chaperone activity, reduced protein aggregation in vitro and alleviated tunicamycin-induced triglyceride and collagen deposition in vivo. Finally, we showed that BBR could reverse ER stress-activated lipogenesis through the ATF6/SREBP-1c pathway in vitro. These results indicated that BBR may be a new therapeutic strategy against hepatic steatosis and non-alcoholic steatohepatitis.
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Affiliation(s)
- Zhiguo Zhang
- Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Department of Endocrinology and Metabolism, China National Research Center for Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Bo Li
- Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Department of Endocrinology and Metabolism, China National Research Center for Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China.,Department of Endocrinology, Xinhua Hospital, Shanghai 200092, China
| | - Xiangjian Meng
- Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Department of Endocrinology and Metabolism, China National Research Center for Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China.,Department of Endocrinology, Yijishan Hospital of Wannan Medical College, Wuhu, Anhui Province 241000, China
| | - Shuangshuang Yao
- Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Department of Endocrinology and Metabolism, China National Research Center for Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Lina Jin
- Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Department of Endocrinology and Metabolism, China National Research Center for Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Jian Yang
- Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Department of Endocrinology and Metabolism, China National Research Center for Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Jiqiu Wang
- Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Department of Endocrinology and Metabolism, China National Research Center for Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Huizhi Zhang
- Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Department of Endocrinology and Metabolism, China National Research Center for Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Zhijian Zhang
- Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Department of Endocrinology and Metabolism, China National Research Center for Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Dongsheng Cai
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York 10461, USA
| | - Yifei Zhang
- Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Department of Endocrinology and Metabolism, China National Research Center for Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Guang Ning
- Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Department of Endocrinology and Metabolism, China National Research Center for Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
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29
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A novel Hsp70 inhibitor prevents cell intoxication with the actin ADP-ribosylating Clostridium perfringens iota toxin. Sci Rep 2016; 6:20301. [PMID: 26839186 PMCID: PMC4738285 DOI: 10.1038/srep20301] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 12/30/2015] [Indexed: 12/14/2022] Open
Abstract
Hsp70 family proteins are folding helper proteins involved in a wide variety of cellular pathways. Members of this family interact with key factors in signal transduction, transcription, cell-cycle control, and stress response. Here, we developed the first Hsp70 low molecular weight inhibitor specifically targeting the peptide binding site of human Hsp70. After demonstrating that the inhibitor modulates the Hsp70 function in the cell, we used the inhibitor to show for the first time that the stress-inducible chaperone Hsp70 functions as molecular component for entry of a bacterial protein toxin into mammalian cells. Pharmacological inhibition of Hsp70 protected cells from intoxication with the binary actin ADP-ribosylating iota toxin from Clostridium perfringens, the prototype of a family of enterotoxins from pathogenic Clostridia and inhibited translocation of its enzyme component across cell membranes into the cytosol. This finding offers a starting point for novel therapeutic strategies against certain bacterial toxins.
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30
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Bonnot T, Bancel E, Chambon C, Boudet J, Branlard G, Martre P. Changes in the nuclear proteome of developing wheat (Triticum aestivum L.) grain. FRONTIERS IN PLANT SCIENCE 2015; 6:905. [PMID: 26579155 PMCID: PMC4623401 DOI: 10.3389/fpls.2015.00905] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2015] [Accepted: 10/10/2015] [Indexed: 05/24/2023]
Abstract
Wheat grain end-use value is determined by complex molecular interactions that occur during grain development, including those in the cell nucleus. However, our knowledge of how the nuclear proteome changes during grain development is limited. Here, we analyzed nuclear proteins of developing wheat grains collected during the cellularization, effective grain-filling, and maturation phases of development, respectively. Nuclear proteins were extracted and separated by two-dimensional gel electrophoresis. Image analysis revealed 371 and 299 reproducible spots in gels with first dimension separation along pH 4-7 and pH 6-11 isoelectric gradients, respectively. The relative abundance of 464 (67%) protein spots changed during grain development. Abundance profiles of these proteins clustered in six groups associated with the major phases and phase transitions of grain development. Using nano liquid chromatography-tandem mass spectrometry to analyse 387 variant and non-variant protein spots, 114 different proteins were identified that were classified into 16 functional classes. We noted that some proteins involved in the regulation of transcription, like HMG1/2-like protein and histone deacetylase HDAC2, were most abundant before the phase transition from cellularization to grain-filling, suggesting that major transcriptional changes occur during this key developmental phase. The maturation period was characterized by high relative abundance of proteins involved in ribosome biogenesis. Data are available via ProteomeXchange with identifier PXD002999.
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Affiliation(s)
- Titouan Bonnot
- UMR1095 Genetics, Diversity and Ecophysiology of Cereals, Institut National de la Recherche AgronomiqueClermont-Ferrand, France
- UMR1095 Genetics, Diversity and Ecophysiology of Cereals, Blaise Pascal UniversityAubière, France
| | - Emmanuelle Bancel
- UMR1095 Genetics, Diversity and Ecophysiology of Cereals, Institut National de la Recherche AgronomiqueClermont-Ferrand, France
- UMR1095 Genetics, Diversity and Ecophysiology of Cereals, Blaise Pascal UniversityAubière, France
| | - Christophe Chambon
- Metabolism Exploration Platform Proteomic Component, Institut National de la Recherche AgronomiqueSaint-Genès Champanelle, France
| | - Julie Boudet
- UMR1095 Genetics, Diversity and Ecophysiology of Cereals, Institut National de la Recherche AgronomiqueClermont-Ferrand, France
- UMR1095 Genetics, Diversity and Ecophysiology of Cereals, Blaise Pascal UniversityAubière, France
| | - Gérard Branlard
- UMR1095 Genetics, Diversity and Ecophysiology of Cereals, Institut National de la Recherche AgronomiqueClermont-Ferrand, France
- UMR1095 Genetics, Diversity and Ecophysiology of Cereals, Blaise Pascal UniversityAubière, France
| | - Pierre Martre
- UMR1095 Genetics, Diversity and Ecophysiology of Cereals, Institut National de la Recherche AgronomiqueClermont-Ferrand, France
- UMR1095 Genetics, Diversity and Ecophysiology of Cereals, Blaise Pascal UniversityAubière, France
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31
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Dekker SL, Kampinga HH, Bergink S. DNAJs: more than substrate delivery to HSPA. Front Mol Biosci 2015; 2:35. [PMID: 26176011 PMCID: PMC4485348 DOI: 10.3389/fmolb.2015.00035] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Accepted: 06/12/2015] [Indexed: 11/20/2022] Open
Abstract
Proteins are essential components of cellular life, as building blocks, but also to guide and execute all cellular processes. Proteins require a three-dimensional folding, which is constantly being challenged by their environment. Challenges including elevated temperatures or redox changes can alter this fold and result in misfolding of proteins or even aggregation. Cells are equipped with several pathways that can deal with protein stress. Together, these pathways are referred to as the protein quality control network. The network comprises degradation and (re)folding pathways that are intertwined due to the sharing of components and by the overlap in affinity for substrates. Here, we will give examples of this sharing and intertwinement of protein degradation and protein folding and discuss how the fate of a substrate is determined. We will focus on the ubiquitylation of substrates and the role of Hsp70 co-chaperones of the DNAJ class in this process.
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Affiliation(s)
- Suzanne L Dekker
- Department of Cell Biology, University Medical Center Groningen, University of Groningen Groningen, Netherlands
| | - Harm H Kampinga
- Department of Cell Biology, University Medical Center Groningen, University of Groningen Groningen, Netherlands
| | - Steven Bergink
- Department of Cell Biology, University Medical Center Groningen, University of Groningen Groningen, Netherlands
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32
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Costanzo M, Cisterna B, Vella A, Cestari T, Covi V, Tabaracci G, Malatesta M. Low ozone concentrations stimulate cytoskeletal organization, mitochondrial activity and nuclear transcription. Eur J Histochem 2015; 59:2515. [PMID: 26150162 PMCID: PMC4503975 DOI: 10.4081/ejh.2015.2515] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Revised: 04/01/2015] [Accepted: 04/04/2015] [Indexed: 12/16/2022] Open
Abstract
Ozone therapy is a modestly invasive procedure based on the regeneration capabilities of low ozone concentrations and used in medicine as an alternative/adjuvant treatment for different diseases. However, the cellular mechanisms accounting for the positive effects of mild ozonization are still largely unexplored. To this aim, in the present study the effects of low ozone concentrations (1 to 20 µg O3/mL O2) on structural and functional cell features have been investigated in vitro by using morphological, morphometrical, cytochemical and immunocytochemical techniques at bright field, fluorescence and transmission electron microscopy. Cells exposed to pure O2 or air served as controls. The results demonstrated that the effects of ozone administration are dependent on gas concentration, and the cytoskeletal organization, mitochondrial activity and nuclear transcription may be differently affected. This suggests that, to ensure effective and permanent metabolic cell activation, ozone treatments should take into account the cytological and cytokinetic features of the different tissues.
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Abstract
The proper folding of proteins is continuously challenged by intrinsic and extrinsic stresses, and the accumulation of toxic misfolded proteins is associated with many human diseases. Eukaryotic cells have evolved a complex network of protein quality control pathways to protect the proteome, and these pathways are specialized for each subcellular compartment. While many details have been elucidated for how the cytosol and endoplasmic reticulum counteract proteotoxic stress, relatively little is known about the pathways protecting the nucleus from protein misfolding. Proper maintenance of nuclear proteostasis has important implications in preserving genomic integrity, as well as for aging and disease. Here, we offer a conceptual framework for how proteostasis is maintained in this organelle. We define the particular requirements that must be considered for the nucleus to manage proteotoxic stress, summarize the known and implicated pathways of nuclear protein quality control, and identify the unresolved questions in the field.
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Affiliation(s)
- Yoko Shibata
- Department of Molecular Biosciences, Rice Institute for Biomedical Research, Northwestern University, Evanston, IL 60208, USA
| | - Richard I Morimoto
- Department of Molecular Biosciences, Rice Institute for Biomedical Research, Northwestern University, Evanston, IL 60208, USA.
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34
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Latonen L. Protein aggregation in neurodegenerative disease: the nucleolar connection. AIMS MOLECULAR SCIENCE 2015. [DOI: 10.3934/molsci.2015.3.324] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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35
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Nucleocytoplasmic transport under stress conditions and its role in HSP70 chaperone systems. Biochim Biophys Acta Gen Subj 2014; 1840:2953-60. [DOI: 10.1016/j.bbagen.2014.04.022] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Revised: 04/11/2014] [Accepted: 04/28/2014] [Indexed: 11/20/2022]
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36
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Koizumi S, Ohama N, Mizoi J, Shinozaki K, Yamaguchi-Shinozaki K. Functional analysis of the Hikeshi-like protein and its interaction with HSP70 in Arabidopsis. Biochem Biophys Res Commun 2014; 450:396-400. [PMID: 24942879 DOI: 10.1016/j.bbrc.2014.05.128] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Accepted: 05/27/2014] [Indexed: 12/27/2022]
Abstract
Heat shock proteins (HSPs) refold damaged proteins and are an essential component of the heat shock response. Previously, the 70 kDa heat shock protein (HSP70) has been reported to translocate into the nucleus in a heat-dependent manner in many organisms. In humans, the heat-induced translocation of HSP70 requires the nuclear carrier protein Hikeshi. In the Arabidopsis genome, only one gene encodes a protein with high homology to Hikeshi, and we named this homolog Hikeshi-like (HKL) protein. In this study, we show that two Arabidopsis HSP70 isoforms accumulate in the nucleus in response to heat shock and that HKL interacts with these HSP70s. Our histochemical analysis revealed that HKL is predominantly expressed in meristematic tissues, suggesting the potential importance of HKL during cell division in Arabidopsis. In addition, we show that HKL regulates HSP70 localization, and HKL overexpression conferred thermotolerance to transgenic Arabidopsis plants. Our results suggest that HKL plays a positive role in the thermotolerance of Arabidopsis plants and cooperatively interacts with HSP70.
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Affiliation(s)
- Shinya Koizumi
- Laboratory of Plant Molecular Physiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Naohiko Ohama
- Laboratory of Plant Molecular Physiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Junya Mizoi
- Laboratory of Plant Molecular Physiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Kazuo Shinozaki
- RIKEN Plant Science Center, 1-7-22 Suehiro-cho, Tsurumi, Yokohama, Kanagawa 230-0045, Japan
| | - Kazuko Yamaguchi-Shinozaki
- Laboratory of Plant Molecular Physiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
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Nuclear phosphoproteome of developing chickpea seedlings (Cicer arietinum L.) and protein-kinase interaction network. J Proteomics 2014; 105:58-73. [PMID: 24747304 DOI: 10.1016/j.jprot.2014.04.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Revised: 03/31/2014] [Accepted: 04/02/2014] [Indexed: 11/21/2022]
Abstract
UNLABELLED Nucleus, the control centre of eukaryotic cell, houses most of the genetic machineries required for gene expression and their regulation. Post translational modifications of proteins, particularly phosphorylation control a wide variety of cellular processes but its functional connectivity, in plants, is still elusive. This study profiled the nuclear phosphoproteome of a grain legume, chickpea, to gain better understanding of such event. Intact nuclei were isolated from 3-week-old seedlings using two independent methods, and nuclear proteins were resolved by 2-DE. In a separate set of experiments, phosphoproteins were enriched using IMAC method and resolved by 1-DE. The separated proteins were stained with phosphospecific Pro-Q Diamond stain. Proteomic analyses led to the identification of 107 putative phosphoproteins, of which 86 were non-redundant. Multiple sites of phosphorylation were predicted on several key elements, which included both regulatory and functional proteins. The analysis revealed an array of phosphoproteins, presumably involved in a variety of cellular functions, viz., protein folding (24%), signalling and gene regulation (22%), DNA replication, repair and modification (16%), and metabolism (13%), among others. These results represent the first nucleus-specific phosphoproteome map of a non-model legume, which would provide insights into the possible function of protein phosphorylation in plants. BIOLOGICAL SIGNIFICANCE Chickpea is grown over 10 million hectares of land worldwide, and global production hovers around 8.5 million metric tons annually. Despite its nutritional merits, it is often referred to as 'orphan' legume and has remained outside the realm of large-scale functional genomics studies. While current chickpea genome initiative has primarily focused on sequence information and functional annotation, proteomics analyses are limited. It is thus important to study the proteome of the cell organelle particularly the nucleus, which harbors most of the genetic information and gene expression machinery. Phosphorylation-dependent modulation of gene expression plays a vital role but the complex networks of phosphorylation are poorly understood. This inventory of nuclear phosphoproteins would provide valuable insights into the dynamic regulation of cellular phenotype through phosphorylation. This article is part of a Special Issue entitled: Proteomics of non-model organisms.
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den Engelsman J, van de Schootbrugge C, Yong J, Pruijn GJM, Boelens WC. Pseudophosphorylated αB-crystallin is a nuclear chaperone imported into the nucleus with help of the SMN complex. PLoS One 2013; 8:e73489. [PMID: 24023879 PMCID: PMC3762725 DOI: 10.1371/journal.pone.0073489] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Accepted: 07/22/2013] [Indexed: 11/25/2022] Open
Abstract
The human small heat shock protein αB-crystallin (HspB5) is a molecular chaperone which is mainly localized in the cytoplasm. A small fraction can also be found in nuclear speckles, of which the localization is mediated by successional phosphorylation at Ser-59 and Ser-45. αB-crystallin does not contain a canonical nuclear localization signal sequence and the mechanism by which αB-crystallin is imported into the nucleus is not known. Here we show that after heat shock pseudophosphorylated αB-crystallin mutant αB-STD, in which all three phosphorylatable serine residues (Ser-19, Ser-45 and Ser-59) were replaced by negatively charged aspartate residues, is released from the nuclear speckles. This allows αB-crystallin to chaperone proteins in the nucleoplasm, as shown by the ability of αB-STD to restore nuclear firefly luciferase activity after a heat shock. With the help of a yeast two-hybrid screen we found that αB-crystallin can interact with the C-terminal part of Gemin3 and confirmed this interaction by co-immunoprecipitation. Gemin3 is a component of the SMN complex, which is involved in the assembly and nuclear import of U-snRNPs. Knockdown of Gemin3 in an in situ nuclear import assay strongly reduced the accumulation of αB-STD in nuclear speckles. Furthermore, depletion of SMN inhibited nuclear import of fluorescently labeled recombinant αB-STD in an in vitro nuclear import assay, which could be restored by the addition of purified SMN complex. These results show that the SMN-complex facilitates the accumulation of hyperphosphorylated αB-crystallin in nuclear speckles, thereby creating a chaperone depot enabling a rapid chaperone function in the nucleus in response to stress.
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Affiliation(s)
- John den Engelsman
- Department of Biomolecular Chemistry, Institute for Molecules and Materials and Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen, Nijmegen, The Netherlands
| | - Chantal van de Schootbrugge
- Department of Biomolecular Chemistry, Institute for Molecules and Materials and Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen, Nijmegen, The Netherlands
| | - Jeongsik Yong
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota Twin Cities, Minneapolis, Minnesota, United States of America
| | - Ger J. M. Pruijn
- Department of Biomolecular Chemistry, Institute for Molecules and Materials and Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen, Nijmegen, The Netherlands
| | - Wilbert C. Boelens
- Department of Biomolecular Chemistry, Institute for Molecules and Materials and Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen, Nijmegen, The Netherlands
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Steel R, Cross RS, Ellis SL, Anderson RL. Hsp70 architecture: the formation of novel polymeric structures of Hsp70.1 and Hsc70 after proteotoxic stress. PLoS One 2012; 7:e52351. [PMID: 23285004 PMCID: PMC3526589 DOI: 10.1371/journal.pone.0052351] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2012] [Accepted: 11/16/2012] [Indexed: 12/04/2022] Open
Abstract
Heat induces Hsp70.1 (HSPA1) and Hsc70 (HSPA8) to form complex detergent insoluble cytoplasmic and nuclear structures that are distinct from the cytoskeleton and internal cell membranes. These novel structures have not been observed by earlier immunofluorescence studies as they are obscured by the abundance of soluble Hsp70.1/Hsc70 present in cells. While resistant to detergents, these Hsp70 structures display complex intracellular dynamics and are efficiently disaggregated by ATP, indicating that this pool of Hsp70.1/Hsc70 retains native function and regulation. Hsp70.1 promotes the repair of proteotoxic damage and cell survival after stress. In heated fibroblasts expressing Hsp70.1, Hsp70.1 and Hsc70 complexes are efficiently disaggregated before the cells undergo-heat induced apoptosis. In the absence of Hsp70.1, fibroblasts have increased rates of heat-induced apoptosis and maintain stable insoluble Hsc70 structures. The differences in the intracellular distribution of Hsp70.1 and Hsc70, combined with the ability of Hsp70.1, but not Hsc70, to promote the disaggregation of insoluble Hsp70.1/Hsc70 complexes, indicate that these two closely related proteins perform distinctly different cellular functions in heated cells.
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Affiliation(s)
- Rohan Steel
- Peter MacCallum Cancer Centre, St Andrew’s Place, East Melbourne, Victoria, Australia
| | - Ryan S. Cross
- Peter MacCallum Cancer Centre, St Andrew’s Place, East Melbourne, Victoria, Australia
| | - Sarah L. Ellis
- Peter MacCallum Cancer Centre, St Andrew’s Place, East Melbourne, Victoria, Australia
- The Sir Peter MacCallum Department of Oncology, The University of Melbourne, Parkville, Victoria, Australia
| | - Robin L. Anderson
- Peter MacCallum Cancer Centre, St Andrew’s Place, East Melbourne, Victoria, Australia
- The Sir Peter MacCallum Department of Oncology, The University of Melbourne, Parkville, Victoria, Australia
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Wiech M, Olszewski MB, Tracz-Gaszewska Z, Wawrzynow B, Zylicz M, Zylicz A. Molecular mechanism of mutant p53 stabilization: the role of HSP70 and MDM2. PLoS One 2012; 7:e51426. [PMID: 23251530 PMCID: PMC3520893 DOI: 10.1371/journal.pone.0051426] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2012] [Accepted: 10/29/2012] [Indexed: 12/12/2022] Open
Abstract
Numerous p53 missense mutations possess gain-of-function activities. Studies in mouse models have demonstrated that the stabilization of p53 R172H (R175H in human) mutant protein, by currently unknown factors, is a prerequisite for its oncogenic gain-of-function phenotype such as tumour progression and metastasis. Here we show that MDM2-dependent ubiquitination and degradation of p53 R175H mutant protein in mouse embryonic fibroblasts is partially inhibited by increasing concentration of heat shock protein 70 (HSP70/HSPA1-A). These phenomena correlate well with the appearance of HSP70-dependent folding intermediates in the form of dynamic cytoplasmic spots containing aggregate-prone p53 R175H and several molecular chaperones. We propose that a transient but recurrent interaction with HSP70 may lead to an increase in mutant p53 protein half-life. In the presence of MDM2 these pseudoaggregates can form stable amyloid-like structures, which occasionally merge into an aggresome. Interestingly, formation of folding intermediates is not observed in the presence of HSC70/HSPA8, the dominant-negative K71S variant of HSP70 or HSP70 inhibitor. In cancer cells, where endogenous HSP70 levels are already elevated, mutant p53 protein forms nuclear aggregates without the addition of exogenous HSP70. Aggregates containing p53 are also visible under conditions where p53 is partially unfolded: 37°C for temperature-sensitive variant p53 V143A and 42°C for wild-type p53. Refolding kinetics of p53 indicate that HSP70 causes transient exposure of p53 aggregate-prone domain(s). We propose that formation of HSP70- and MDM2-dependent protein coaggregates in tumours with high levels of these two proteins could be one of the mechanisms by which mutant p53 is stabilized. Moreover, sequestration of p73 tumour suppressor protein by these nuclear aggregates may lead to gain-of-function phenotypes.
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Affiliation(s)
- Milena Wiech
- Department of Molecular Biology, International Institute of Molecular and Cell Biology in Warsaw, Warsaw, Poland
- The Nencki Institute of Experimental Biology, PAS, Warsaw, Poland
| | - Maciej B. Olszewski
- Department of Molecular Biology, International Institute of Molecular and Cell Biology in Warsaw, Warsaw, Poland
| | - Zuzanna Tracz-Gaszewska
- Department of Molecular Biology, International Institute of Molecular and Cell Biology in Warsaw, Warsaw, Poland
- The Institute of Biochemistry and Biophysics, PAS, Warsaw, Poland
| | - Bartosz Wawrzynow
- Department of Molecular Biology, International Institute of Molecular and Cell Biology in Warsaw, Warsaw, Poland
| | - Maciej Zylicz
- Department of Molecular Biology, International Institute of Molecular and Cell Biology in Warsaw, Warsaw, Poland
| | - Alicja Zylicz
- Department of Molecular Biology, International Institute of Molecular and Cell Biology in Warsaw, Warsaw, Poland
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Mercer N, Ramakrishnan B, Boeggeman E, Qasba PK. Applications of site-specific labeling to study HAMLET, a tumoricidal complex of α-lactalbumin and oleic acid. PLoS One 2011; 6:e26093. [PMID: 22016817 PMCID: PMC3189925 DOI: 10.1371/journal.pone.0026093] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2011] [Accepted: 09/19/2011] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Alpha-lactalbumin (α-LA) is a calcium-bound mammary gland-specific protein that is found in milk. This protein is a modulator of β1,4-galactosyltransferase enzyme, changing its acceptor specificity from N-acetyl-glucosamine to glucose, to produce lactose, milk's main carbohydrate. When calcium is removed from α-LA, it adopts a molten globule form, and this form, interestingly, when complexed with oleic acid (OA) acquires tumoricidal activity. Such a complex made from human α-LA (hLA) is known as HAMLET (Human A-lactalbumin Made Lethal to Tumor cells), and its tumoricidal activity has been well established. METHODOLOGY/PRINCIPAL FINDINGS In the present work, we have used site-specific labeling, a technique previously developed in our laboratory, to label HAMLET with biotin, or a fluoroprobe for confocal microscopy studies. In addition to full length hLA, the α-domain of hLA (αD-hLA) alone is also included in the present study. We have engineered these proteins with a 17-amino acid C-terminal extension (hLA-ext and αD-hLA-ext). A single Thr residue in this extension is glycosylated with 2-acetonyl-galactose (C2-keto-galactose) using polypeptide-α-N-acetylgalactosaminyltransferase II (ppGalNAc-T2) and further conjugated with aminooxy-derivatives of fluoroprobe or biotin molecules. CONCLUSIONS/SIGNIFICANCE We found that the molten globule form of hLA and αD-hLA proteins, with or without C-terminal extension, and with and without the conjugated fluoroprobe or biotin molecule, readily form a complex with OA and exhibits tumoricidal activity similar to HAMLET made with full-length hLA protein. The confocal microscopy studies with fluoroprobe-labeled samples show that these proteins are internalized into the cells and found even in the nucleus only when they are complexed with OA. The HAMLET conjugated with a single biotin molecule will be a useful tool to identify the cellular components that are involved with it in the tumoricidal activity.
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Affiliation(s)
- Natalia Mercer
- Structural Glycobiology Section, CCR-Nanobiology Program, Center for Cancer Research, NCI-Frederick, Frederick, Maryland, United States of America
| | - Boopathy Ramakrishnan
- Structural Glycobiology Section, CCR-Nanobiology Program, Center for Cancer Research, NCI-Frederick, Frederick, Maryland, United States of America
- Basic Science Program, SAIC-Frederick, Inc., NCI-Frederick, Frederick, Maryland, United States of America
| | - Elizabeth Boeggeman
- Structural Glycobiology Section, CCR-Nanobiology Program, Center for Cancer Research, NCI-Frederick, Frederick, Maryland, United States of America
- Basic Science Program, SAIC-Frederick, Inc., NCI-Frederick, Frederick, Maryland, United States of America
| | - Pradman K. Qasba
- Structural Glycobiology Section, CCR-Nanobiology Program, Center for Cancer Research, NCI-Frederick, Frederick, Maryland, United States of America
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Katz S, Kushnir O, Tovy A, Siman Tov R, Ankri S. The Entamoeba histolytica methylated LINE-binding protein EhMLBP provides protection against heat shock. Cell Microbiol 2011; 14:58-70. [DOI: 10.1111/j.1462-5822.2011.01697.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Hadley KC, Borrelli MJ, Lepock JR, McLaurin J, Croul SE, Guha A, Chakrabartty A. Multiphoton ANS fluorescence microscopy as an in vivo sensor for protein misfolding stress. Cell Stress Chaperones 2011; 16:549-61. [PMID: 21484286 PMCID: PMC3156256 DOI: 10.1007/s12192-011-0266-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2011] [Revised: 03/23/2011] [Accepted: 03/24/2011] [Indexed: 11/30/2022] Open
Abstract
The inability of cells to maintain protein folding homeostasis is implicated in the development of neurodegenerative diseases, malignant transformation, and aging. We find that multiphoton fluorescence imaging of 1-anilinonaphthalene-8-sulfonate (ANS) can be used to assess cellular responses to protein misfolding stresses. ANS is relatively nontoxic and enters live cells and cells or tissues fixed in formalin. In an animal model of Alzheimer's disease, ANS fluorescence imaging of brain tissue sections reveals the binding of ANS to fibrillar deposits of amyloid peptide (Aβ) in amyloid plaques and in cerebrovascular amyloid. ANS imaging also highlights non-amyloid deposits of glial fibrillary acidic protein in brain tumors. Cultured cells under normal growth conditions possess a number of ANS-binding structures. High levels of ANS fluorescence are associated with the endoplasmic reticulum (ER), Golgi, and lysosomes-regions of protein folding and degradation. Nuclei are virtually devoid of ANS binding sites. Additional ANS binding is triggered by hyperthermia, thermal lesioning, proteasome inhibition, and induction of ER stress. We also use multiphoton imaging of ANS binding to follow the in vivo recovery of cells from protein-damaging insults over time. We find that ANS fluorescence tracks with the binding of the molecular chaperone Hsp70 in compartments where Hsp70 is present. ANS highlights the sensitivity of specific cellular targets, including the nucleus and particularly the nucleolus, to thermal stress and proteasome inhibition. Multiphoton imaging of ANS binding should be a useful probe for monitoring protein misfolding stress in cells.
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Affiliation(s)
- Kevin C. Hadley
- Department of Medical Biophysics, University of Toronto. Ontario Cancer Institute, 101 College Street, Toronto, ON M5G 1L7 Canada
| | - Michael J. Borrelli
- Department of Radiology, University of Arkansas for Medical Sciences, 4301 W. Markham St., Little Rock, AR 72205 USA
| | - James R. Lepock
- Department of Medical Biophysics, University of Toronto. Ontario Cancer Institute, 101 College Street, Toronto, ON M5G 1L7 Canada
| | - JoAnne McLaurin
- Department of Laboratory Medicine and Pathobiology, Centre for Research in Neurodegenerative Diseases, University of Toronto, 6 Queen’s Park Cres. W., Toronto, ON M5S 3H2 Canada
| | - Sidney E. Croul
- Department of Laboratory Medicine and Pathobiology, University of Toronto, UHN Path 11E426 Toronto General Hospital, 200 Elizabeth St., Toronto, ON M5G 2C4 Canada
| | - Abhijit Guha
- Arthur and Sonia Labatt Brain Tumour Centre, Hospital for Sick Children’s Research Institute, Toronto, ON M5G 1X8 Canada
| | - Avijit Chakrabartty
- Campbell Family Institute for Cancer Research, Ontario Cancer Institute, University Health Network, Toronto, ON Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ON Canada
- Department of Biochemistry, University of Toronto, Toronto, ON Canada
- Toronto Medical Discovery Tower 4-307, MaRS Center 101 College Street, Toronto, ON M5G 1L7 Canada
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van Ham TJ, Holmberg MA, van der Goot AT, Teuling E, Garcia-Arencibia M, Kim HE, Du D, Thijssen KL, Wiersma M, Burggraaff R, van Bergeijk P, van Rheenen J, Jerre van Veluw G, Hofstra RMW, Rubinsztein DC, Nollen EAA. Identification of MOAG-4/SERF as a regulator of age-related proteotoxicity. Cell 2010; 142:601-12. [PMID: 20723760 DOI: 10.1016/j.cell.2010.07.020] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2009] [Revised: 03/31/2010] [Accepted: 06/17/2010] [Indexed: 01/03/2023]
Abstract
Fibrillar protein aggregates are the major pathological hallmark of several incurable, age-related, neurodegenerative disorders. These aggregates typically contain aggregation-prone pathogenic proteins, such as amyloid-beta in Alzheimer's disease and alpha-synuclein in Parkinson's disease. It is, however, poorly understood how these aggregates are formed during cellular aging. Here we identify an evolutionarily highly conserved modifier of aggregation, MOAG-4, as a positive regulator of aggregate formation in C. elegans models for polyglutamine diseases. Inactivation of MOAG-4 suppresses the formation of compact polyglutamine aggregation intermediates that are required for aggregate formation. The role of MOAG-4 in driving aggregation extends to amyloid-beta and alpha-synuclein and is evolutionarily conserved in its human orthologs SERF1A and SERF2. MOAG-4/SERF appears to act independently from HSF-1-induced molecular chaperones, proteasomal degradation, and autophagy. Our results suggest that MOAG-4/SERF regulates age-related proteotoxicity through a previously unexplored pathway, which will open up new avenues for research on age-related, neurodegenerative diseases.
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Affiliation(s)
- Tjakko J van Ham
- Department of Genetics, University Medical Centre Groningen, University of Groningen, Hanzeplein 1, 9700 RB Groningen, the Netherlands
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Virus-Induced Chaperone-Enriched (VICE) domains function as nuclear protein quality control centers during HSV-1 infection. PLoS Pathog 2009; 5:e1000619. [PMID: 19816571 PMCID: PMC2752995 DOI: 10.1371/journal.ppat.1000619] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2009] [Accepted: 09/14/2009] [Indexed: 12/11/2022] Open
Abstract
Virus-Induced Chaperone-Enriched (VICE) domains form adjacent to nuclear viral replication compartments (RC) during the early stages of HSV-1 infection. Between 2 and 3 hours post infection at a MOI of 10, host protein quality control machinery such as molecular chaperones (e.g. Hsc70), the 20S proteasome and ubiquitin are reorganized from a diffuse nuclear distribution pattern to sequestration in VICE domains. The observation that VICE domains contain putative misfolded proteins suggests that they may be similar to nuclear inclusion bodies that form under conditions in which the protein quality control machinery is overwhelmed by the presence of misfolded proteins. The detection of Hsc70 in VICE domains, but not in nuclear inclusion bodies, indicates that Hsc70 is specifically reorganized by HSV-1 infection. We hypothesize that HSV-1 infection induces the formation of nuclear protein quality control centers to remodel or degrade aberrant nuclear proteins that would otherwise interfere with productive infection. Detection of proteolytic activity in VICE domains suggests that substrates may be degraded by the 20S proteasome in VICE domains. FRAP analysis reveals that GFP-Hsc70 is dynamically associated with VICE domains, suggesting a role for Hsc70 in scanning the infected nucleus for misfolded proteins. During 42°C heat shock, Hsc70 is redistributed from VICE domains into RC perhaps to remodel viral replication and regulatory proteins that have become insoluble in these compartments. The experiments presented in this paper suggest that VICE domains are nuclear protein quality control centers that are modified by HSV-1 to promote productive infection. Protein quality control is a protective cellular mechanism by which damaged proteins are refolded or degraded so that they cannot interfere with essential cellular processes. In the event that protein quality control machinery cannot refold or degrade damaged proteins, sequestration of misfolded protein is an alternative protective mechanism for reducing the toxic effects of misfolded protein. Several neurological diseases result from the accumulation of toxic misfolded proteins that cannot be efficiently refolded or degraded. In neurons from patients afflicted with Huntington's disease, misfolded huntingtin protein is sequestered in large aggregates in the nucleus called inclusion bodies. Inclusion bodies also contain protein quality control machinery including molecular chaperones, the proteasome and ubiquitin. Here we report that analogous structures called Virus-Induced Chaperone-Enriched (VICE) domains form in the nucleus of cells infected with Herpes Simplex Virus type 1 (HSV-1). VICE domains contain misfolded protein, chaperones and protein degradation activity. VICE domain formation is efficient in infected cells taxed with high levels of viral protein production. We hypothesize that misfolded proteins that arise in HSV-1-infected cells are sequestered in VICE domains to promote remodeling of misfolded proteins.
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Yamasaki A, Ito H, Yusa J, Sakurai Y, Okuyama N, Ozawa R. Expression of heat shock proteins, Hsp70 and Hsp25, in the rat gingiva after irradiation with a CO2 laser in coagulation mode. J Periodontal Res 2009; 45:323-30. [PMID: 19909401 DOI: 10.1111/j.1600-0765.2009.01239.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND AND OBJECTIVE The therapeutic rationale of low-energy pulsed CO(2) laser coagulation mode has not been clarified yet. We conducted this study to characterize the effect of low-energy pulsed CO(2) laser coagulation mode irradiation of the rat gingiva in terms of the expression of heat shock proteins. MATERIAL AND METHODS Laser irradiation was achieved with the parameters of 5 W, 600 mus pulse duration, and fluence of 326 J/cm(2). The gingiva dissected at different times after irradiation was processed for immunohistochemical examination of the expression of the heat shock proteins, Hsp70 and Hsp25. RESULTS One hour after irradiation, the epithelial keratinocytes facing the laser wound exhibited an overexpression of Hsp70 in their nucleus. The connective tissue cells facing the laser wound, which included fibroblasts and capillary endothelial cells, showed de novo expression of Hsp70 at 3 h post-irradiation, the level of which peaked at 1 d and thereafter decreased. An enhanced and/or de novo expression of Hsp25 in the connective tissue cells facing the laser wound became evident at 3 h after irradiation, and after 1 d the Hsp25-expressing cells increased in number and spread over the wound as wound repair progressed. There was a temporospatial difference in the expression pattern between Hsp70 and Hsp25, with only a few cells appearing to co-express both heat shock proteins. CONCLUSION The CO(2) laser treatment in coagulation mode produced the expression of heat shock proteins, and the findings suggest that while Hsp70 mainly conferred cell protection, Hsp25 was involved in the progress of wound repair as well as cell protection.
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Affiliation(s)
- A Yamasaki
- Division of Oral Pathology, Department of Oral Medical Sciences, Ohu University School of Dentistry, Koriyama, Fukushima, Japan.
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Kotoglou P, Kalaitzakis A, Vezyraki P, Tzavaras T, Michalis LK, Dantzer F, Jung JU, Angelidis C. Hsp70 translocates to the nuclei and nucleoli, binds to XRCC1 and PARP-1, and protects HeLa cells from single-strand DNA breaks. Cell Stress Chaperones 2009; 14:391-406. [PMID: 19089598 PMCID: PMC2728274 DOI: 10.1007/s12192-008-0093-6] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2008] [Revised: 10/28/2008] [Accepted: 11/24/2008] [Indexed: 02/01/2023] Open
Abstract
For many years, there has been uncertainty concerning the reason for Hsp70 translocation to the nucleus and nucleolus. Herein, we propose that Hsp70 translocates to the nucleus and nucleoli in order to participate in pathways related to the protection of the nucleoplasmic DNA or ribosomal DNA from single-strand breaks. The absence of Hsp70 in HeLa cells, via Hsp70 gene silencing (knockdown), indicated the essential role of Hsp70 in DNA integrity. Therefore, HeLa Hsp70 depleted cells were very sensitive in heat treatment and their DNA breaks were multiple compared to that of control HeLa cells. The molecular mechanism with which Hsp70 performs its role at the level of nucleus and nucleolus during stress was examined. Hsp70 co-localizes with PARP1 in the nucleus/nucleoli as was observed in confocal studies and binds to the BCRT domain of PARP1 as was revealed with protein-protein interaction assays. It was also found that Hsp70 binds simultaneously to XRCC1 and PARP-1, indicating that Hsp70 function takes place at the level of DNA repair and possibly at the base excision repair system. Making a hypothetical model, we have suggested that Hsp70 is the molecule that binds and interrelates with PARP1 creating the repair proteins simultaneously, such as XRCC1, at the single-strand DNA breaks. Our data partially clarify a previously unrecognized cellular response to heat stress. Finally, we can speculate that Hsp70 plays a role in the quality and integrity of DNA.
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Affiliation(s)
- Polychronis Kotoglou
- Laboratory of General Biology, Medical School, University of Ioannina, Ioannina, 45110 Greece
| | - Alexandros Kalaitzakis
- Laboratory of General Biology, Medical School, University of Ioannina, Ioannina, 45110 Greece
| | - Patra Vezyraki
- Laboratory of Experimental Physiology, Medical School, University of Ioannina, Ioannina, 45110 Greece
| | - Theodore Tzavaras
- Laboratory of General Biology, Medical School, University of Ioannina, Ioannina, 45110 Greece
| | - Lampros K. Michalis
- Michaileidion Cardiac Center, Medical School, University of Ioannina, Ioannina, 45110 Greece
- Department of Cardiology, Medical School, University of Ioannina, Ioannina, 45110 Greece
| | - Francoise Dantzer
- Integrite du Genome, Ecole Superieure de Biotechnologie de Strasbourg, Unite Mixte de Recherche 7175, 67412 Illkirch, France
| | - Jae U. Jung
- Department of Microbiology and Molecular Genetics, Tumor Virology Division, New England Primate Research Center, Harvard Medical School, 1 Pine Hill Drive, Southborough, MA 01772-9102 USA
| | - Charalampos Angelidis
- Laboratory of General Biology, Medical School, University of Ioannina, Ioannina, 45110 Greece
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HSPB7 is a SC35 speckle resident small heat shock protein. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2009; 1793:1343-53. [PMID: 19464326 DOI: 10.1016/j.bbamcr.2009.05.005] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2008] [Revised: 05/13/2009] [Accepted: 05/15/2009] [Indexed: 01/15/2023]
Abstract
BACKGROUND The HSPB family is one of the more diverse families within the group of HSP families. Some members have chaperone-like activities and/or play a role in cytoskeletal stabilization. Some members also show a dynamic, stress-induced translocation to SC35 splicing speckles. If and how these features are interrelated and if they are shared by all members are yet unknown. METHODS Tissue expression data and interaction and co-regulated gene expression data of the human HSPB members was analyzed using bioinformatics. Using a gene expression library, sub-cellular distribution of the diverse members was analyzed by confocal microscopy. Chaperone activity was measured using a cellular luciferase refolding assay. RESULTS Online databases did not accurately predict the sub-cellular distribution of all the HSPB members. A novel and non-predicted finding was that HSPB7 constitutively localized to SC35 splicing speckles, driven by its N-terminus. Unlike HSPB1 and HSPB5, that chaperoned heat unfolded substrates and kept them folding competent, HSPB7 did not support refolding. CONCLUSION Our data suggest a non-chaperone-like role of HSPB7 at SC35 speckles. GENERAL SIGNIFICANCE The functional divergence between HSPB members seems larger than previously expected and also includes non-canonical members lacking classical chaperone-like functions.
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Cho EK, Choi YJ. A nuclear-localized HSP70 confers thermoprotective activity and drought-stress tolerance on plants. Biotechnol Lett 2009; 31:597-606. [PMID: 19034388 DOI: 10.1007/s10529-008-9880-5] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2008] [Revised: 11/05/2008] [Accepted: 11/10/2008] [Indexed: 12/23/2022]
Abstract
To investigate the function of nuclear-localized plant HSP70, we used NtHSP70-1 isolated from Nicotiana tabacum. The subcellular localization of NtHSP70-1 was identified by fluorescence microscopy for NtHSP70-1/GFP or smGFP fusion proteins in onion epidermal cells, obtained using particle gun bombardment. To analyze the drought-stress tolerance and thermoprotective role of NtHSP70-1, we obtained transgenic tobacco plants that constitutively expressed elevated levels of NtHSP70-1 as well as transgenic plants containing either the vector alone or else having NtHSP70-1 in the antisense orientation. From analysis for genomic DNA in transgenic seedlings after heat stress, NtHSP70-1 helps to prevent the fragmentation and degradation of nuclear DNA during heat stress. In addition, seedlings constitutively overexpressing NtHSP70-1 grew to be healthy plants, whereas transgenic vector or antisense seedlings resulted in death after heat-/drought-stress.
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Affiliation(s)
- Eun Kyung Cho
- Department of Bio-Food Materials, College of Medical Life Science, Silla University, Busan 617-736, South Korea.
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Choudhary MK, Basu D, Datta A, Chakraborty N, Chakraborty S. Dehydration-responsive nuclear proteome of rice (Oryza sativa L.) illustrates protein network, novel regulators of cellular adaptation, and evolutionary perspective. Mol Cell Proteomics 2009; 8:1579-98. [PMID: 19321431 DOI: 10.1074/mcp.m800601-mcp200] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Water deficit or dehydration is the most crucial environmental constraint on plant growth and development and crop productivity. It has been postulated that plants respond and adapt to dehydration by altering their cellular metabolism and by activating various defense machineries. The nucleus, the regulatory hub of the eukaryotic cell, is a dynamic system and a repository of various macromolecules that serve as modulators of cell signaling dictating the cell fate decision. To better understand the molecular mechanisms of dehydration-responsive adaptation in plants, we developed a comprehensive nuclear proteome of rice. The proteome was determined using a sequential method of organellar enrichment followed by two-dimensional electrophoresis-based protein identification by LC-ESI-MS/MS. We initially screened several commercial rice varieties and parental lines and established their relative dehydration tolerance. The differential display of nuclear proteins in the tolerant variety under study revealed 150 spots that showed changes in their intensities by more than 2.5-fold. The proteomics analysis led to the identification of 109 differentially regulated proteins presumably involved in a variety of functions, including transcriptional regulation and chromatin remodeling, signaling and gene regulation, cell defense and rescue, and protein degradation. The dehydration-responsive nuclear proteome revealed a coordinated response involving both regulatory and functional proteins, impinging upon the molecular mechanism of dehydration adaptation. Furthermore a comparison between the dehydration-responsive nuclear proteome of rice and that of a legume, the chickpea, showed an evolutionary divergence in dehydration response comprising a few conserved proteins, whereas most of the proteins may be involved in crop-specific adaptation. These results might help in understanding the spectrum of nuclear proteins and the biological processes they control under dehydration as well as having implications for strategies to improve dehydration tolerance in plants.
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