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Dorsch LM, Schuldt M, dos Remedios CG, Schinkel AFL, de Jong PL, Michels M, Kuster DWD, Brundel BJJM, van der Velden J. Protein Quality Control Activation and Microtubule Remodeling in Hypertrophic Cardiomyopathy. Cells 2019; 8:E741. [PMID: 31323898 PMCID: PMC6678711 DOI: 10.3390/cells8070741] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 07/11/2019] [Accepted: 07/17/2019] [Indexed: 12/14/2022] Open
Abstract
Hypertrophic cardiomyopathy (HCM) is the most common inherited cardiac disorder. It is mainly caused by mutations in genes encoding sarcomere proteins. Mutant forms of these highly abundant proteins likely stress the protein quality control (PQC) system of cardiomyocytes. The PQC system, together with a functional microtubule network, maintains proteostasis. We compared left ventricular (LV) tissue of nine donors (controls) with 38 sarcomere mutation-positive (HCMSMP) and 14 sarcomere mutation-negative (HCMSMN) patients to define HCM and mutation-specific changes in PQC. Mutations in HCMSMP result in poison polypeptides or reduced protein levels (haploinsufficiency, HI). The main findings were 1) several key PQC players were more abundant in HCM compared to controls, 2) after correction for sex and age, stabilizing heat shock protein (HSP)B1, and refolding, HSPD1 and HSPA2 were increased in HCMSMP compared to controls, 3) α-tubulin and acetylated α-tubulin levels were higher in HCM compared to controls, especially in HCMHI, 4) myosin-binding protein-C (cMyBP-C) levels were inversely correlated with α-tubulin, and 5) α-tubulin levels correlated with acetylated α-tubulin and HSPs. Overall, carrying a mutation affects PQC and α-tubulin acetylation. The haploinsufficiency of cMyBP-C may trigger HSPs and α-tubulin acetylation. Our study indicates that proliferation of the microtubular network may represent a novel pathomechanism in cMyBP-C haploinsufficiency-mediated HCM.
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Affiliation(s)
- Larissa M Dorsch
- Department of Physiology, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam Cardiovascular Sciences, 1081 HV Amsterdam, The Netherlands.
| | - Maike Schuldt
- Department of Physiology, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam Cardiovascular Sciences, 1081 HV Amsterdam, The Netherlands
| | - Cristobal G dos Remedios
- Sydney Heart Bank, Discipline of Anatomy, Bosch Institute, University of Sydney, Sydney 2006, Australia
| | - Arend F L Schinkel
- Department of Cardiology, Thoraxcenter, Erasmus Medical Center, 3015 GD Rotterdam, The Netherlands
| | - Peter L de Jong
- Department of Cardiothoracic Surgery, Thoraxcenter, Erasmus Medical Center, 3015 GD Rotterdam, The Netherlands
| | - Michelle Michels
- Department of Cardiology, Thoraxcenter, Erasmus Medical Center, 3015 GD Rotterdam, The Netherlands
| | - Diederik W D Kuster
- Department of Physiology, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam Cardiovascular Sciences, 1081 HV Amsterdam, The Netherlands
| | - Bianca J J M Brundel
- Department of Physiology, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam Cardiovascular Sciences, 1081 HV Amsterdam, The Netherlands
| | - Jolanda van der Velden
- Department of Physiology, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam Cardiovascular Sciences, 1081 HV Amsterdam, The Netherlands
- Netherlands Heart Institute, 3511 EP Utrecht, The Netherlands
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2
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Solé M, Monge M, André M, Quero C. A proteomic analysis of the statocyst endolymph in common cuttlefish (Sepia officinalis): an assessment of acoustic trauma after exposure to sound. Sci Rep 2019; 9:9340. [PMID: 31249355 PMCID: PMC6597576 DOI: 10.1038/s41598-019-45646-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 06/11/2019] [Indexed: 12/21/2022] Open
Abstract
Recent studies, both in laboratory and sea conditions, have demonstrated damage after sound exposure in the cephalopod statocyst sensory epithelium, which secretes endolymph protein. Here, the proteomic analysis of the endolymph was performed before and after sound exposure to assess the effects of exposure to low intensity, low frequency sounds on the statocyst endolymph of the Mediterranean common cuttlefish (Sepia officinalis), determining changes in the protein composition of the statocyst endolymph immediately and 24 h after sound exposure. Significant differences in protein expression were observed, especially 24 h after exposure. A total of 37 spots were significantly different in exposed specimens, 17 of which were mostly related to stress and cytoskeletal structure. Among the stress proteins eight spots corresponding to eight hemocyanin isoforms were under-expressed possible due to lower oxygen consumption. In addition, cytoskeletal proteins such as tubulin alpha chain and intermediate filament protein were also down-regulated after exposure. Thus, endolymph analysis in the context of acoustic stress allowed us to establish the effects at the proteome level and identify the proteins that are particularly sensitive to this type of trauma.
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Affiliation(s)
- M Solé
- Laboratory of Applied Bioacoustics, Technical University of Catalonia, Barcelona TECH, 08800, Rambla exposició s/n, Vilanova i la Geltrú, Barcelona, Spain
| | - M Monge
- Proteomics Laboratory, Vall d'Hebron Institute of Oncology (VHIO), Edifici Collserola, 08035, Barcelona, Spain
| | - M André
- Laboratory of Applied Bioacoustics, Technical University of Catalonia, Barcelona TECH, 08800, Rambla exposició s/n, Vilanova i la Geltrú, Barcelona, Spain.
| | - C Quero
- Department of Biological Chemistry and Molecular Modelling, IQAC (CSIC), Jordi Girona 18, 08034, Barcelona, Spain.
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3
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Miller DJ, Fort PE. Heat Shock Proteins Regulatory Role in Neurodevelopment. Front Neurosci 2018; 12:821. [PMID: 30483047 PMCID: PMC6244093 DOI: 10.3389/fnins.2018.00821] [Citation(s) in RCA: 91] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Accepted: 10/22/2018] [Indexed: 01/20/2023] Open
Abstract
Heat shock proteins (Hsps) are a large family of molecular chaperones that are well-known for their roles in protein maturation, re-folding and degradation. While some Hsps are constitutively expressed in certain regions, others are rapidly upregulated in the presence of stressful stimuli. Numerous stressors, including hyperthermia and hypoxia, can induce the expression of Hsps, which, in turn, interact with client proteins and co-chaperones to regulate cell growth and survival. Such interactions must be tightly regulated, especially at critical points during embryonic and postnatal development. Hsps exhibit specific patterns of expression consistent with a spatio-temporally regulated role in neurodevelopment. There is also growing evidence that Hsps may promote or inhibit neurodevelopment through specific pathways regulating cell differentiation, neurite outgrowth, cell migration, or angiogenesis. This review will examine the regulatory role that these individual chaperones may play in neurodevelopment, and will focus specifically on the signaling pathways involved in the maturation of neuronal and glial cells as well as the underlying vascular network.
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Affiliation(s)
- David J Miller
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI, United States.,Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, United States
| | - Patrice E Fort
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI, United States.,Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, United States
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Xing T, Wang P, Zhao L, Liu R, Zhao X, Xu X, Zhou G. A comparative study of heat shock protein 70 in normal and PSE (pale, soft, exudative)-like muscle from broiler chickens. Poult Sci 2016; 95:2391-6. [DOI: 10.3382/ps/pew181] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Accepted: 04/20/2016] [Indexed: 01/23/2023] Open
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5
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Fontaine SN, Martin MD, Akoury E, Assimon VA, Borysov S, Nordhues BA, Sabbagh JJ, Cockman M, Gestwicki JE, Zweckstetter M, Dickey CA. The active Hsc70/tau complex can be exploited to enhance tau turnover without damaging microtubule dynamics. Hum Mol Genet 2015; 24:3971-81. [PMID: 25882706 DOI: 10.1093/hmg/ddv135] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Accepted: 04/13/2015] [Indexed: 11/12/2022] Open
Abstract
The pathological accumulation of abnormally hyperphosphorylated and aggregated tau, a neuronal microtubule (MT)-associated protein that functions to maintain MT stability, is implicated in a number of hereditary and sporadic neurodegenerative diseases including frontotemporal dementia and Alzheimer's disease. Targeting tau for the treatment of these diseases is an area of intense interest and toward that end, modulation of cellular molecular chaperones is a potential therapeutic target. In particular, the constitutive Hsp70 isoform, Hsc70, seems highly interconnected with tau, preserving tau protein levels and synergizing with it to assemble MTs. But the relationship between tau and Hsc70, as well as the impact of this interaction in neurons and its therapeutic implications remain unknown. Using a human dominant negative Hsc70 that resembles isoform selective inhibition of this important chaperone, we found for the first time that Hsc70 activity is required to stimulate MT assembly in cells and brain. However, surprisingly, active Hsc70 also requires active tau to regulate MT assembly in vivo, suggesting that tau acts in some ways as a co-chaperone for Hsc70 to coordinate MT assembly. This was despite tau binding to Hsc70 as substrate, as determined biochemically. Moreover, we show that while chronic Hsc70 inhibition damaged MT dynamics, intermittent treatment with a small molecule Hsp70 inhibitor lowered tau in brain tissue without disrupting MT integrity. Thus, in tauopathies, where MT injury would be detrimental to neurons, the unique relationship of tau with the Hsc70 machinery can be exploited to deplete tau levels without damaging MT networks.
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Affiliation(s)
- Sarah N Fontaine
- Department of Molecular Medicine, College of Medicine, Byrd Alzheimer's Institute, University of South Florida, Tampa, FL 33613, USA, James A. Haley Veteran's Hospital, 13000 Bruce B. Downs Blvd, Tampa, FL 33612, USA
| | - Mackenzie D Martin
- Department of Molecular Medicine, College of Medicine, Byrd Alzheimer's Institute, University of South Florida, Tampa, FL 33613, USA
| | - Elias Akoury
- Department for NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Göttingen 37077, Germany, German Center for Neurodegenerative Diseases (DZNE), Göttingen 37077, Germany, Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), University Medical Center, Göttingen 37073, Germany and
| | - Victoria A Assimon
- Institute for Neurodegenerative Disease, University of California at San Francisco, San Francisco, CA 94158, USA
| | - Sergiy Borysov
- Department of Molecular Medicine, College of Medicine, Byrd Alzheimer's Institute, University of South Florida, Tampa, FL 33613, USA
| | - Bryce A Nordhues
- Department of Molecular Medicine, College of Medicine, Byrd Alzheimer's Institute, University of South Florida, Tampa, FL 33613, USA, James A. Haley Veteran's Hospital, 13000 Bruce B. Downs Blvd, Tampa, FL 33612, USA
| | - Jonathan J Sabbagh
- Department of Molecular Medicine, College of Medicine, Byrd Alzheimer's Institute, University of South Florida, Tampa, FL 33613, USA, James A. Haley Veteran's Hospital, 13000 Bruce B. Downs Blvd, Tampa, FL 33612, USA
| | - Matt Cockman
- Department of Molecular Medicine, College of Medicine, Byrd Alzheimer's Institute, University of South Florida, Tampa, FL 33613, USA
| | - Jason E Gestwicki
- Institute for Neurodegenerative Disease, University of California at San Francisco, San Francisco, CA 94158, USA
| | - Markus Zweckstetter
- Department for NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Göttingen 37077, Germany, German Center for Neurodegenerative Diseases (DZNE), Göttingen 37077, Germany, Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), University Medical Center, Göttingen 37073, Germany and
| | - Chad A Dickey
- Department of Molecular Medicine, College of Medicine, Byrd Alzheimer's Institute, University of South Florida, Tampa, FL 33613, USA, James A. Haley Veteran's Hospital, 13000 Bruce B. Downs Blvd, Tampa, FL 33612, USA,
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Chen YJ, Lai KC, Kuo HH, Chow LP, Yih LH, Lee TC. HSP70 colocalizes with PLK1 at the centrosome and disturbs spindle dynamics in cells arrested in mitosis by arsenic trioxide. Arch Toxicol 2014; 88:1711-23. [PMID: 24623308 DOI: 10.1007/s00204-014-1222-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Accepted: 03/03/2014] [Indexed: 11/26/2022]
Abstract
Heat shock protein 70 (HSP70) has been shown to be a substrate of Polo-like kinase 1 (PLK1), and it prevents cells arrested in mitosis by arsenic trioxide (ATO) from dying. Here, we report that HSP70 participates in ATO-induced spindle elongation, which interferes with mitosis progression. Our results demonstrate that HSP70 and PLK1 colocalize at the centrosome in ATO-arrested mitotic cells. HSP70 located at the centrosome was found to be phosphorylated by PLK1 at Ser⁶³¹ and Ser⁶³³. Moreover, unlike wild-type HSP70 (HSP70(wt)) and its phosphomimetic mutant (HSP70(SS631,633DD)), a phosphorylation-resistant mutant of HSP70 (HSP70(SS631,633AA)) failed to localize at the centrosome. ATO-induced spindle elongation was abolished in cells overexpressing HSP70(SS631,633AA). Conversely, mitotic spindles in cells ectopically expressing HSP70(SS631,633DD) were more resistant to nocodazole-induced depolymerization than in those expressing HSP70(wt) or HSP70(SS631,633AA). In addition, inhibition of PLK1 significantly reduced HSP70 phosphorylation and induced early onset of apoptosis in ATO-arrested mitotic cells. Taken together, our results indicate that PLK1-mediated phosphorylation and centrosomal localization of HSP70 may interfere with spindle dynamics and prevent apoptosis of ATO-arrested mitotic cells.
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Affiliation(s)
- Yu-Ju Chen
- Institute of Biomedical Sciences, Academia Sinica, Taipei, 11529, Taiwan
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7
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Parker AL, Kavallaris M, McCarroll JA. Microtubules and their role in cellular stress in cancer. Front Oncol 2014; 4:153. [PMID: 24995158 PMCID: PMC4061531 DOI: 10.3389/fonc.2014.00153] [Citation(s) in RCA: 254] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Accepted: 06/03/2014] [Indexed: 01/08/2023] Open
Abstract
Microtubules are highly dynamic structures, which consist of α- and β-tubulin heterodimers, and are involved in cell movement, intracellular trafficking, and mitosis. In the context of cancer, the tubulin family of proteins is recognized as the target of the tubulin-binding chemotherapeutics, which suppress the dynamics of the mitotic spindle to cause mitotic arrest and cell death. Importantly, changes in microtubule stability and the expression of different tubulin isotypes as well as altered post-translational modifications have been reported for a range of cancers. These changes have been correlated with poor prognosis and chemotherapy resistance in solid and hematological cancers. However, the mechanisms underlying these observations have remained poorly understood. Emerging evidence suggests that tubulins and microtubule-associated proteins may play a role in a range of cellular stress responses, thus conferring survival advantage to cancer cells. This review will focus on the importance of the microtubule-protein network in regulating critical cellular processes in response to stress. Understanding the role of microtubules in this context may offer novel therapeutic approaches for the treatment of cancer.
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Affiliation(s)
- Amelia L Parker
- Tumour Biology and Targeting Program, Children's Cancer Institute Australia, Lowy Cancer Research Centre, University of New South Wales , Sydney, NSW , Australia
| | - Maria Kavallaris
- Tumour Biology and Targeting Program, Children's Cancer Institute Australia, Lowy Cancer Research Centre, University of New South Wales , Sydney, NSW , Australia ; Australian Centre for NanoMedicine, University of New South Wales , Sydney, NSW , Australia
| | - Joshua A McCarroll
- Tumour Biology and Targeting Program, Children's Cancer Institute Australia, Lowy Cancer Research Centre, University of New South Wales , Sydney, NSW , Australia ; Australian Centre for NanoMedicine, University of New South Wales , Sydney, NSW , Australia
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8
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Zhong M, Zheng K, Chen M, Xiang Y, Jin F, Ma K, Qiu X, Wang Q, Peng T, Kitazato K, Wang Y. Heat-shock protein 90 promotes nuclear transport of herpes simplex virus 1 capsid protein by interacting with acetylated tubulin. PLoS One 2014; 9:e99425. [PMID: 24901434 PMCID: PMC4047101 DOI: 10.1371/journal.pone.0099425] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Accepted: 05/14/2014] [Indexed: 01/04/2023] Open
Abstract
Although it is known that inhibitors of heat shock protein 90 (Hsp90) can inhibit herpes simplex virus type 1 (HSV-1) infection, the role of Hsp90 in HSV-1 entry and the antiviral mechanisms of Hsp90 inhibitors remain unclear. In this study, we found that Hsp90 inhibitors have potent antiviral activity against standard or drug-resistant HSV-1 strains and viral gene and protein synthesis are inhibited in an early phase. More detailed studies demonstrated that Hsp90 is upregulated by virus entry and it interacts with virus. Hsp90 knockdown by siRNA or treatment with Hsp90 inhibitors significantly inhibited the nuclear transport of viral capsid protein (ICP5) at the early stage of HSV-1 infection. In contrast, overexpression of Hsp90 restored the nuclear transport that was prevented by the Hsp90 inhibitors, suggesting that Hsp90 is required for nuclear transport of viral capsid protein. Furthermore, HSV-1 infection enhanced acetylation of α-tubulin and Hsp90 interacted with the acetylated α-tubulin, which is suppressed by Hsp90 inhibition. These results demonstrate that Hsp90, by interacting with acetylated α-tubulin, plays a crucial role in viral capsid protein nuclear transport and may provide novel insight into the role of Hsp90 in HSV-1 infection and offer a promising strategy to overcome drug-resistance.
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Affiliation(s)
- Meigong Zhong
- Guangzhou Jinan Biomedicine Research and Development Center, National Engineering Research Center of Genetic Medicine, Jinan University, Guangzhou, PR China; College of Pharmacy, Jinan University, Guangzhou, PR China
| | - Kai Zheng
- Guangzhou Jinan Biomedicine Research and Development Center, National Engineering Research Center of Genetic Medicine, Jinan University, Guangzhou, PR China
| | - Maoyun Chen
- Guangzhou Jinan Biomedicine Research and Development Center, National Engineering Research Center of Genetic Medicine, Jinan University, Guangzhou, PR China; College of Pharmacy, Jinan University, Guangzhou, PR China
| | - Yangfei Xiang
- Guangzhou Jinan Biomedicine Research and Development Center, National Engineering Research Center of Genetic Medicine, Jinan University, Guangzhou, PR China
| | - Fujun Jin
- Guangzhou Jinan Biomedicine Research and Development Center, National Engineering Research Center of Genetic Medicine, Jinan University, Guangzhou, PR China; College of Pharmacy, Jinan University, Guangzhou, PR China
| | - Kaiqi Ma
- Guangzhou Jinan Biomedicine Research and Development Center, National Engineering Research Center of Genetic Medicine, Jinan University, Guangzhou, PR China
| | - Xianxiu Qiu
- Guangzhou Jinan Biomedicine Research and Development Center, National Engineering Research Center of Genetic Medicine, Jinan University, Guangzhou, PR China; College of Pharmacy, Jinan University, Guangzhou, PR China
| | - Qiaoli Wang
- Guangzhou Jinan Biomedicine Research and Development Center, National Engineering Research Center of Genetic Medicine, Jinan University, Guangzhou, PR China
| | - Tao Peng
- State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, PR China
| | - Kaio Kitazato
- Division of Molecular Pharmacology of Infectious Agents, Department of Molecular Microbiology and Immunology, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
| | - Yifei Wang
- Guangzhou Jinan Biomedicine Research and Development Center, National Engineering Research Center of Genetic Medicine, Jinan University, Guangzhou, PR China
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9
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Parrotta L, Cresti M, Cai G. Heat-shock protein 70 binds microtubules and interacts with kinesin in tobacco pollen tubes. Cytoskeleton (Hoboken) 2013; 70:522-37. [PMID: 24039249 DOI: 10.1002/cm.21134] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2013] [Revised: 08/15/2013] [Accepted: 08/21/2013] [Indexed: 11/11/2022]
Abstract
The heat-shock proteins of 70 kDa are a family of ubiquitously expressed proteins important for protein folding. Heat-shock protein 70 assists other nascent proteins to achieve the spatial structure and ultimately helps the cell to protect against stress factors, such as heat. These proteins are localized in different cellular compartments and are associated with the cytoskeleton. We identified a heat-shock protein 70 isoform in the pollen tube of tobacco that binds to microtubules in an ATP-dependent manner. The heat-shock protein 70 was identified as part of the so-called ATP-MAP (ATP-dependent microtubule-associated protein) fraction, which also includes the 90-kDa kinesin, a mitochondria-associated motor protein. The identity of heat-shock protein 70 was validated by immunological assays and mass spectrometry. Sequence analysis showed that this heat-shock protein 70 is more similar to specific heat-shock proteins of Arabidopsis than to corresponding proteins of tobacco. Two-dimensional electrophoresis indicated that this heat-shock protein 70 isoform only is part of the ATP-MAP fraction and that is associated with the mitochondria of pollen tubes. Sedimentation assays showed that the binding of heat-shock protein 70 to microtubules is not affected by AMPPNP but it increases in the presence of the 90-kDa kinesin. Binding of heat-shock protein 70 to microtubules occurs only partially in the presence of ATP but it does not occur if, in addition to ATP, the 90-kDa kinesin is also present. Data suggest that the binding (but not the release) of heat-shock protein 70 to microtubules is facilitated by the 90-kDa kinesin.
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Affiliation(s)
- Luigi Parrotta
- Dipartimento di Scienze della Vita, Università di Siena, via Mattioli 4, 53100, Siena, Italy
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10
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Makhnevych T, Houry WA. The control of spindle length by Hsp70 and Hsp110 molecular chaperones. FEBS Lett 2013; 587:1067-72. [DOI: 10.1016/j.febslet.2013.02.018] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Revised: 02/06/2013] [Accepted: 02/07/2013] [Indexed: 12/20/2022]
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11
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Rupik W, Jasik K, Bembenek J, Widłak W. The expression patterns of heat shock genes and proteins and their role during vertebrate's development. Comp Biochem Physiol A Mol Integr Physiol 2011; 159:349-66. [DOI: 10.1016/j.cbpa.2011.04.002] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2011] [Revised: 04/02/2011] [Accepted: 04/04/2011] [Indexed: 02/07/2023]
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12
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Wang S, Toth ME, Bereczki E, Santha M, Guan ZZ, Winblad B, Pei JJ. Interplay between glycogen synthase kinase-3β and tau in the cerebellum of Hsp27 transgenic mouse. J Neurosci Res 2011; 89:1267-75. [PMID: 21544852 DOI: 10.1002/jnr.22660] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2010] [Revised: 01/26/2011] [Accepted: 03/09/2011] [Indexed: 12/19/2022]
Abstract
The association between heat shock protein 27 (Hsp27) and hyperphosphorylated tau has gained attention for more than a decade, but it has never been explored in vivo. In the present study, we found that tau phosphorylated at S396/404 (PHF-1) and S262 sites was significantly increased in the cerebellum of Hsp27 transgenic mice, which was concomitant with increased glycogen synthase kinase-3β (GSK3β) phosphorylated at Y216 and decreased GSK3β phosphorylated at S9. Neither 70-kDa ribosomal protein S6 kinase (p70S6K; total p70S6K, p70S6K at T389, and p70S6K at T421/S424) nor protein phosphatase PP2A (total PP2A, PP2A at Y307, methylated or demethylated PP2A) was changed. This suggests that the increased tau phosphorylation at S396/404 and S262 sites may be induced by Hsp27 through enhancement of GSK3β activity in the mouse cerebellum.
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Affiliation(s)
- Shan Wang
- Karolinska Institutet, Department of Neurobiology, Care Sciences and Society, KI-Alzheimer's Disease Research Center, Novum, Huddinge, Sweden
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13
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Vydra N, Winiarski B, Rak-Raszewska A, Piglowski W, Mazurek A, Scieglinska D, Widlak W. The expression pattern of the 70-kDa heat shock protein Hspa2 in mouse tissues. Histochem Cell Biol 2009; 132:319-30. [PMID: 19462178 DOI: 10.1007/s00418-009-0605-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/28/2009] [Indexed: 11/26/2022]
Abstract
The highest expression level of a 70-kDa heat shock protein family member Hspa2 is detected specifically in meiotic and post-meiotic male germ cells, which is reflected by original name of this protein, i.e., testis-specific Hsp70. However, this chaperon protein could be also detected in certain somatic tissues. Here, the extra-testicular expression pattern of mouse Hspa2 was analyzed. We found expression of Hspa2 in various epithelial cells including lining of bronchioles and oviduct, columnar epithelium of endometrium, epithelial reticular cells of thymus, transitional epithelium of the urinary bladder, or ependymal cells covering walls of the ventricular system of the brain. Surprisingly, Hspa2 was a putative secretory protein in intestine, endometrial glands and subcommissural organ. Hspa2 was detected in central and peripheral nervous system: in neuron's bodies and fiber tracts, in the subventricular zone of the lateral ventricles, in the dentate gyrus of the hippocampus, in enteric ganglia of the gastrointestinal tract. Hspa2 was also expressed in smooth muscles and at low level in immune system (in germinal centers associated with B-lymphocyte production). In addition to somatic tissues listed above, Hspa2 was detected in oocytes arrested at diplotene of the first meiotic division.
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Affiliation(s)
- Natalia Vydra
- Department of Tumor Biology, Maria Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Gliwice Branch, 44-101, Gliwice, Poland
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Sarkar M, Kuret J, Lee G. Two motifs within the tau microtubule-binding domain mediate its association with the hsc70 molecular chaperone. J Neurosci Res 2009; 86:2763-73. [PMID: 18500754 DOI: 10.1002/jnr.21721] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Tau, a microtubule-associated protein with multiple phosphorylation sites, forms aggregates that correlate with neurodegeneration in Alzheimer's disease and several other neurodegenerative diseases, termed tauopathies. Hsc70 is a highly expressed constitutive chaperone that can drive conformational change in proteins, prevent the aggregation of its substrates, recognize misfolded substrates, and facilitate their degradation. Here, we show that hsc70 binds to the microtubule-binding domain of tau in vitro and in vivo, without an absolute requirement for tau phosphorylation. Binding requires a carboxy-terminal region of hsc70 comprising its peptide-binding and variable domains. We have identified two hsc70 binding sites on tau and hydrophobic amino acids crucial for hsc70 binding. Interestingly, these hsc70 binding sites correspond to the beta-structure elements that have been previously reported to facilitate tau aggregation. Thus, it is possible that hsc70 binding might directly inhibit tau-tau interactions that precede tau oligomerization and aggregation. Our results provide an important stimulus for research into how the hsc70-tau interaction might affect tau fate in normal cells and in disease.
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Affiliation(s)
- Mitul Sarkar
- Program in Neuroscience and Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine, The University of Iowa, Iowa City, Iowa 52242, USA
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15
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Amiri A, Noei F, Feroz T, Lee JM. Geldanamycin Anisimycins Activate Rho and Stimulate Rho- and ROCK-Dependent Actin Stress Fiber Formation. Mol Cancer Res 2007; 5:933-42. [PMID: 17855662 DOI: 10.1158/1541-7786.mcr-06-0362] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Heat shock protein 90 (Hsp90) is a member of the heat shock family of molecular chaperones that regulate protein conformation and activity. Hsp90 regulates multiple cell signaling pathways by controlling the abundance and activity of several important protein kinases and cell cycle-related proteins. In this report, we show that inhibition of Hsp90 by geldanamycin or its derivative, 17-allylamino-17-desmethoxygeldamycin, leads to activation of the Rho GTPase and a dramatic increase in actin stress fiber formation in human tumor cell lines. Inactivation of Rho prevents geldanamycin-induced actin reorganization. Hsp90 inactivation does not alter the appearance of filopodia or lamellipodia and tubulin architecture is not visibly perturbed. Our observations suggest that Hsp90 has an important and specific role in regulating Rho activity and Rho-dependent actin cytoskeleton remodeling.
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Affiliation(s)
- Anahita Amiri
- Department of Biochemistry, University of Ottawa, 451 Smyth Road, Ottawa, Ontario, Canada K1H 8M5
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16
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Mitra G, Saha A, Gupta TD, Poddar A, Das KP, Das Gupta SK, Bhattacharyya B. Chaperone-mediated inhibition of tubulin self-assembly. Proteins 2007; 67:112-20. [PMID: 17243182 DOI: 10.1002/prot.21286] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Molecular chaperones are known to play an important role in facilitating the proper folding of many newly synthesized proteins. Here, we have shown that chaperone proteins exhibit another unique property to inhibit tubulin self-assembly efficiently. Chaperones tested include alpha-crystallin from bovine eye lenses, HSP16.3, HSP70 from Mycobacterium tuberculosis and alpha (s)-casein from milk. All of them inhibit polymerization in a dose-dependent manner independent of assembly inducers used. The critical concentration of MTP polymerization increases with increasing concentration of HSP16.3. Increase in chaperone concentration lowers the extent of polymerization and increases the lag time of self-assembly reaction. Although the addition of a chaperone at the early stage of elongation phase shows no effect on polymerization, the same concentration of chaperone inhibits polymerization completely when added before the initiation of polymerization. Bindings of HSP16.3 and alpha (s)-casein to tubulin have been confirmed using isothermal titration calorimetry. Affinity constants of tubulin are 5.3 xx 10(4) and 9.8 xx 10(5) M(-1) for HSP16.3 and alpha (s)-casein, respectively. Thermodynamic parameters indicate favourable entropy and enthalpy changes for both chaperones-tubulin interactions. Positive entropy change suggests that the interaction is hydrophobic in nature and desolvation occurring during formation of tubulin-chaperone complex. On the basis of thermodynamic data and observations made upon addition of chaperone at early elongation phase or before the initiation of polymerization, we hypothesize that chaperones bind tubulin at the protein-protein interaction site involved in the nucleation phase of self-assembly.
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Affiliation(s)
- Gopa Mitra
- Department of Biochemistry, Bose Institute, Centenary Campus, Calcutta 700054, India
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17
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Riederer BM. Microtubule-associated protein 1B, a growth-associated and phosphorylated scaffold protein. Brain Res Bull 2006; 71:541-58. [PMID: 17292797 DOI: 10.1016/j.brainresbull.2006.11.012] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2006] [Accepted: 11/28/2006] [Indexed: 11/25/2022]
Abstract
Microtubule-associated protein 1B, MAP1B, is one of the major growth associated and cytoskeletal proteins in neuronal and glial cells. It is present as a full length protein or may be fragmented into a heavy chain and a light chain. It is essential to stabilize microtubules during the elongation of dendrites and neurites and is involved in the dynamics of morphological structures such as microtubules, microfilaments and growth cones. MAP1B function is modulated by phosphorylation and influences microtubule stability, microfilaments and growth cone motility. Considering its large size, several interactions with a variety of other proteins have been reported and there is increasing evidence that MAP1B plays a crucial role in the stability of the cytoskeleton and may have other cellular functions. Here we review molecular and functional aspects of this protein, evoke its role as a scaffold protein and have a look at several pathologies where the protein may be involved.
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Affiliation(s)
- Beat M Riederer
- Département de Biologie Cellulaire et de Morphologi), Université de Lausanne, 9 rue du Bugnon, CH-1005 Lausanne, Switzerland.
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18
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Verrills NM, Liem NL, Liaw TYE, Hood BD, Lock RB, Kavallaris M. Proteomic analysis reveals a novel role for the actin cytoskeleton in vincristine resistant childhood leukemia--an in vivo study. Proteomics 2006; 6:1681-94. [PMID: 16456880 DOI: 10.1002/pmic.200500417] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Intrinsic or acquired resistance to vincristine (VCR), an antimicrotubule agent used in the treatment of childhood acute lymphoblastic leukemia (ALL), is a major clinical problem. Using a clinically relevant NOD/SCID mouse xenograft model of ALL, we established that alterations in the actin and tubulin cytoskeleton are involved in in vivo VCR resistance. Altered protein expression between VCR-sensitive ALL xenografts, and xenografts with intrinsic or acquired VCR resistance, was identified using 2-D DIGE coupled with MS. Of the 19 proteins displaying altered expression, 11 are associated with the actin cytoskeleton. Altered expression of the actin- and/or tubulin-binding proteins gelsolin, moesin, ezrin, tropomyosin, CAP-G, HSP27, HSP70, TCP-1, and stathmin were associated with in vivo VCR resistance. The actin-regulating protein gelsolin was increased in both acquired and resistant leukemia as confirmed by immunoblotting and gene expression. The major cytoskeletal protein, gamma-actin, was down-regulated in the VCR-resistant leukemia xenografts; in contrast, there was no significant change in beta-actin expression. This study provides the first evidence for a role of the actin cytoskeleton in intrinsic and acquired in vivo antimicrotubule drug resistance in childhood leukemia and highlights the power of 2-D DIGE for the discovery of resistance markers, pharmacoproteomics, and signaling pathways in cancer.
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Affiliation(s)
- Nicole M Verrills
- Children's Cancer Institute Australia for Medical Research, Randwick, NSW, Australia
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19
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Liu SH, Cheng HH, Huang SY, Yiu PC, Chang YC. Studying the Protein Organization of the Postsynaptic Density by a Novel Solid Phase- and Chemical Cross-linking-based Technology. Mol Cell Proteomics 2006; 5:1019-32. [PMID: 16501281 DOI: 10.1074/mcp.m500299-mcp200] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Agarose beads carrying a cleavable, fluorescent, and photoreactive cross-linking reagent on the surface were synthesized and used to selectively pull out the proteins lining the surface of supramolecules. A quantitative comparison of the abundances of various proteins in the sample pulled out by the beads from supramolecules with their original abundances could provide information on the spatial arrangement of these proteins in the supramolecule. The usefulness of these synthetic beads was successfully verified by trials using a synthetic protein complex consisting of three layers of different proteins on glass coverslips. By using these beads, we determined the interior or superficial locations of five major and 19 minor constituent proteins in the postsynaptic density (PSD), a large protein complex and the landmark structure of asymmetric synapses in the mammalian central nervous system. The results indicate that alpha,beta-tubulins, dynein heavy chain, microtubule-associated protein 2, spectrin, neurofilament H and M subunits, an hsp70 protein, alpha-internexin, dynamin, and PSD-95 protein reside in the interior of the PSD. Dynein intermediate chain, alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate receptors, kainate receptors, N-cadherin, beta-catenin, N-ethylmaleimide-sensitive factor, an hsc70 protein, and actin reside on the surface of the PSD. The results further suggest that the N-methyl-d-aspartate receptors and the alpha-subunits of calcium/calmodulin-dependent protein kinase II are likely to reside on the surface of the PSD although with unique local protein organizations. Based on our results and the known interactions between various PSD proteins from data mining, a model for the molecular organization of the PSD is proposed.
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Affiliation(s)
- Szu-Heng Liu
- Department of Life Science, National Tsing Hua University, Hsinchu 30013, Taiwan, Republic of China
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20
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O'Connell PA, Pinto DM, Chisholm KA, MacRae TH. Characterization of the microtubule proteome during post-diapause development of Artemia franciscana. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2006; 1764:920-8. [PMID: 16631421 DOI: 10.1016/j.bbapap.2006.03.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 12/10/2005] [Revised: 02/23/2006] [Accepted: 03/13/2006] [Indexed: 01/02/2023]
Abstract
The microtubule proteome encompasses tubulin and a diverse group of proteins which associate with tubulin upon microtubule formation. These proteins either determine microtubule organization and function or their activity is influenced by microtubule association. To characterize the microtubule proteome in Artemia franciscana, tubulin assembly was induced with taxol in vitro after 0 and 12 h of post-diapause development. Proteins obtained by extraction of microtubules with 0.5 M NaCl were electrophoresed in two-dimensional gels and analyzed by mass spectrometry. Fifty-five proteins were identified with 10 of these occurring at both developmental stages, and multiple isoforms were observed for some proteins of the Artemia proteome. Their functions include roles in membrane transport, metabolism, chaperoning and protein synthesis, thus reflecting physiological properties of encysted Artemia such as stress resistance and the ability to rapidly initiate post-diapause development. For example, chaperones may protect tubulin during encystment and facilitate folding in metabolically active embryos. Additionally, the interaction of metabolic enzymes with microtubules funnels reaction intermediates, potentially enhancing efficiency within biochemical processes. This study represents the first systematic characterization of a crustacean microtubule proteome. Although it is difficult to be certain that all protein associations documented herein occur in vivo, the results suggest how protein-protein interactions contribute to cytoplasmic organization while implying how Artemia embryos resist stress and remain capable of development once diapause terminates.
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Affiliation(s)
- Paul A O'Connell
- Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada B3H 4J1
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21
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Kuwabara H, Yoneda M, Hayasaki H, Nakamura T, Mori H. Glucose regulated proteins 78 and 75 bind to the receptor for hyaluronan mediated motility in interphase microtubules. Biochem Biophys Res Commun 2006; 339:971-6. [PMID: 16329989 DOI: 10.1016/j.bbrc.2005.11.101] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2005] [Accepted: 11/14/2005] [Indexed: 10/25/2022]
Abstract
The receptor for hyaluronan mediated motility (RHAMM), which is a hyaluronan-binding protein, is a centrosomal and microtubal protein. Here, we have identified two RHAMM-binding proteins, glucose regulated protein (GRP) 78 and GRP75, using co-immunoprecipitation analysis. These two proteins directly bound to glutathione-S-transferase-RHAMM fusion proteins. By double immunostaining, GRP78 and GRP75 colocalized with RHAMM in interphase microtubules, but were separated in mitotic spindles. Prevention of microtubule polymerization by TN-16 and vincristine sulfate induced RHAMM overexpression without a significant change in GRP78/75. Taken together, GRP78/75 and RHAMM complexes may stabilize microtubules in the interphase, associated with a downregulation of RHAMM. These results reveal a new biochemical activity of RHAMM.
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Affiliation(s)
- Hiroko Kuwabara
- Department of Pathology, Osaka Medical College, 2-7, Takatsuki, Osaka 569-8686, Japan.
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22
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Gache V, Louwagie M, Garin J, Caudron N, Lafanechere L, Valiron O. Identification of proteins binding the native tubulin dimer. Biochem Biophys Res Commun 2005; 327:35-42. [PMID: 15629426 DOI: 10.1016/j.bbrc.2004.11.138] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2004] [Indexed: 11/25/2022]
Abstract
Microtubules play an essential role in eukaryotic cells, where they perform a wide variety of functions. In this paper, we describe the characterization of proteins associated to tubulin dimer in its native form, using affinity chromatography and mass spectrometry. We used an immunoaffinity column with coupled-monoclonal antibody directed against the alpha-tubulin C-terminus. Tubulin was first loaded onto the column, then interphase and mitotic cell lysates were chromatographed. Tubulin-binding proteins were eluted using a peptide mimicking the alpha-tubulin C-terminus. Elution fractions were analyzed by SDS-PAGE, and a total of 14 proteins were identified with high confidence by mass spectrometry. These proteins could be grouped in four classes: known tubulin-binding proteins, one microtubule-associated protein, heat shock proteins, and proteins that were not shown previously to bind tubulin dimer or microtubules.
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Affiliation(s)
- Vincent Gache
- INSERM Unité 366, DRDC/CS, CEA-Grenoble, 17 rue des Martyrs, 38054 Grenoble Cedex 9, France
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23
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Verrills NM, Walsh BJ, Cobon GS, Hains PG, Kavallaris M. Proteome analysis of vinca alkaloid response and resistance in acute lymphoblastic leukemia reveals novel cytoskeletal alterations. J Biol Chem 2003; 278:45082-93. [PMID: 12949081 DOI: 10.1074/jbc.m303378200] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Vinca alkaloids are used widely in the treatment of both childhood and adult cancers. Their cellular target is the beta-tubulin subunit of alpha/beta-tubulin heterodimers, and they act to inhibit cell division by disrupting microtubule dynamics. Despite the effectiveness of these agents, drug resistance is a major clinical problem. To identify the underlying mechanisms behind vinca alkaloid resistance, we have performed high resolution differential proteome analysis. Treatment of drug-sensitive human leukemia cells (CCRF-CEM) with vincristine identified numerous proteins involved in the cellular response to vincristine. In addition, differential protein expression was analyzed in leukemia cell lines selected for resistance to vincristine (CEM/VCR R) and vinblastine (CEM/VLB100). This combined proteomic approach identified 10 proteins altered in both vinca alkaloid response and resistance: beta-tubulin, alpha-tubulin, actin, heat shock protein 90beta, 14-3-3tau, 14-3-3epsilon, L-plastin, lamin B1, heterogeneous nuclear ribonuclear protein-F, and heterogeneous nuclear ribonuclear protein-K. Several of these proteins have not previously been associated with drug resistance and are thus novel targets for elucidation of resistance mechanisms. In addition, seven of these proteins are associated with the tubulin and/or actin cytoskeletons. This study provides novel insights into the interrelationship between the microtubule and microfilament systems in vinca alkaloid resistance.
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MESH Headings
- Actins/metabolism
- Amino Acid Sequence
- Cell Line, Tumor
- Cytoskeleton/metabolism
- Drug Resistance, Neoplasm
- Electrophoresis, Gel, Two-Dimensional
- Electrophoresis, Polyacrylamide Gel
- Gene Expression Regulation, Neoplastic
- Humans
- Immunoblotting
- Molecular Sequence Data
- Precursor Cell Lymphoblastic Leukemia-Lymphoma/drug therapy
- Protein Structure, Tertiary
- Proteome
- Sequence Homology, Amino Acid
- Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
- Time Factors
- Tubulin/metabolism
- Vinblastine/pharmacology
- Vinca Alkaloids/pharmacology
- Vincristine/pharmacology
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Affiliation(s)
- Nicole M Verrills
- Children's Cancer Institute Australia for Medical Research, High St. (P. O. Box 81), Randwick, New South Wales 2031, Australia
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24
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Saito Y, Yamagishi N, Ishihara K, Hatayama T. Identification of alpha-tubulin as an hsp105alpha-binding protein by the yeast two-hybrid system. Exp Cell Res 2003; 286:233-40. [PMID: 12749852 DOI: 10.1016/s0014-4827(03)00054-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Hsp105alpha is a mammalian stress protein that belongs to the HSP105/110 family. Hsp105alpha prevents stress-induced apoptosis in neuronal cells and binds to Hsp70/Hsc70 and suppresses the Hsp70 chaperone activity in vitro. In this study, to further elucidate the function of Hsp105alpha, we searched for Hsp105alpha-binding proteins by screening a mouse FM3A cell cDNA library with full-length Hsp105alpha using the yeast two-hybrid system and obtained alpha-tubulin as an Hsp105alpha-binding protein. Hsp105alpha bound directly to alpha-tubulin both in vitro and in vivo. Indirect immunofluorescence analysis with anti-Hsp105 and anti-alpha-tubulin antibodies indicated that Hsp105alpha was colocalized with microtubules. Furthermore, the disorganization of microtubules induced by heat shock was prevented in Hsp105alpha-overexpressing COS-7 cells. These findings suggested that Hsp105alpha associates with alpha-tubulin and microtubules in cells and plays a role in protection of microtubules under conditions of stress.
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Affiliation(s)
- Youhei Saito
- Department of Biochemistry, Kyoto Pharmaceutical University, 5 Nakauchicho, Misasagi, Yamashina-ku, Kyoto 607-8414, Japan
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25
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Glowala M, Mazurek A, Piddubnyak V, Fiszer-Kierzkowska A, Michalska J, Krawczyk Z. HSP70 overexpression increases resistance of V79 cells to cytotoxicity of airborne pollutants, but does not protect the mitotic spindle against damage caused by airborne toxins. Toxicology 2002; 170:211-9. [PMID: 11788158 DOI: 10.1016/s0300-483x(01)00556-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Exposure of Chinese hamster V79 cells to extracts of airborne pollutants induced formation of multipolar or incomplete mitotic spindles. To find out whether overexpression of the HSP70 chaperone protein could protect spindles against airborne toxins we constructed V79 cells stably transfected with an expression vector containing rat heat-inducible hsp70.1 gene under the control of a constitutive CMV promoter. When cells were incubated with extracts of airborne pollutants (5-20 microg/ml) no protective effect of the HSP70 protein against mitotic spindle damage was observed. Moreover, at 20 microg/ml of extracts of airborne toxins the frequency of mitotic malformations was even higher in HSP70-overexpressing cells than in control ones. Extracts of airborne pollutants of 50 microg/ml blocked the formation of mitotic figures both in control and HSP70-overexpressing cells and led to destruction of cell nuclei. However, the HSP70-overproducing cells exhibited higher survival rates when exposed to heat shock and airborne toxins than the control ones, as determined by MTT assay. This suggests that HSP70 overexpression-a frequent feature of cancer cells-should be considered as a factor facilitating survival of cells with damaged mitotic spindles and aberrantly segregated chromosomes.
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Affiliation(s)
- Magdalena Glowala
- Department of Tumor Biology, Centre of Oncology - Maria Skłodowska-Curie Memorial Institute, Wybrzeze Armii Krajowej 15, 44-101, Gliwice, Poland
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26
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Inaguma Y, Ito H, Iwamoto I, Saga S, Kato K. AlphaB-crystallin phosphorylated at Ser-59 is localized in centrosomes and midbodies during mitosis. Eur J Cell Biol 2001; 80:741-8. [PMID: 11831387 DOI: 10.1078/0171-9335-00203] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We have reported that the three serine residues in alphaB-crystallin are phosphorylated under various stress conditions. We prepared affinity-purified antibodies recognizing each of the phosphorylated serine residues (Ser-19, Ser-45, and Ser-59, respectively) in alphaB-crystallin with peptides (p19S, p45S, or p59S) that contained the corresponding phosphorylated serine residue. Immunocytochemically anti-p45S antibodies stained the cytoplasm of mitotic cells (J. Biol. Chem. 273, 28,346-28,354). We have now found that the anti-p59S antibodies recognize centrosomes and midbodies of dividing cells. alphaB-Crystallin was the only protein recognized by the anti-p59S antibodies in Western blot analyses of isolated centrosome fractions. alphaB-Crystallin phosphorylated at Ser-59 was localized at the microtubule organizing centers by means of double staining with anti-beta-tubulin antibody in aster formation analysis and was co-localized with gamma-tubulin in centrosomes. Gamma-Tubulin was co-immunoprecipitated with alphaB-crystallin in U373 glioma cell extracts. On the other hand, the location of the phosphorylated alphaB-crystallin deviated from that of alpha-tubulin or gamma-tubulin in the midbody region. Taken together with the evidences that several chaperones are distributed to centrosomes, these results suggest that alphaB-crystallin as a chaperone might be also involved in the quality control of proteins.
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Affiliation(s)
- Y Inaguma
- Department of Biochemistry, Institute for Developmental Research, Aichi Human Service Center, Japan
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27
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Snoeckx LH, Cornelussen RN, Van Nieuwenhoven FA, Reneman RS, Van Der Vusse GJ. Heat shock proteins and cardiovascular pathophysiology. Physiol Rev 2001; 81:1461-97. [PMID: 11581494 DOI: 10.1152/physrev.2001.81.4.1461] [Citation(s) in RCA: 242] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
In the eukaryotic cell an intrinsic mechanism is present providing the ability to defend itself against external stressors from various sources. This defense mechanism probably evolved from the presence of a group of chaperones, playing a crucial role in governing proper protein assembly, folding, and transport. Upregulation of the synthesis of a number of these proteins upon environmental stress establishes a unique defense system to maintain cellular protein homeostasis and to ensure survival of the cell. In the cardiovascular system this enhanced protein synthesis leads to a transient but powerful increase in tolerance to such endangering situations as ischemia, hypoxia, oxidative injury, and endotoxemia. These so-called heat shock proteins interfere with several physiological processes within several cell organelles and, for proper functioning, are translocated to different compartments following stress-induced synthesis. In this review we describe the physiological role of heat shock proteins and discuss their protective potential against various stress agents in the cardiovascular system.
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Affiliation(s)
- L H Snoeckx
- Department of Physiology, Faculty of Medicine, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands.
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28
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Barnes JA, Dix DJ, Collins BW, Luft C, Allen JW. Expression of inducible Hsp70 enhances the proliferation of MCF-7 breast cancer cells and protects against the cytotoxic effects of hyperthermia. Cell Stress Chaperones 2001; 6:316-25. [PMID: 11795468 PMCID: PMC434414 DOI: 10.1379/1466-1268(2001)006<0316:eoihet>2.0.co;2] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Heat shock proteins (Hsps) are ubiquitous proteins that are induced following exposure to sublethal heat shock, are highly conserved during evolution, and protect cells from damage through their function as molecular chaperones. Some cancers demonstrate elevated levels of Hsp70, and their expression has been associated with cell proliferation, disease prognosis, and resistance to chemotherapy. In this study, we developed a tetracycline-regulated gene expression system to determine the specific effects of inducible Hsp70 on cell growth and protection against hyperthermia in MCF-7 breast cancer cells. MCF-7 cells expressing high levels of Hsp70 demonstrated a significantly faster doubling time (39 hours) compared with nonoverexpressing control cells (54 hours). The effect of elevated Hsp70 on cell proliferation was characterized further by 5-bromo-2'deoxyuridine labeling, which demonstrated a higher number of second and third division metaphases in cells at 42 and 69 hours, respectively. Estimates based on cell cycle analysis and mean doubling time indicated that Hsp70 may be exerting its growth-stimulating effect on MCF-7 cells primarily by shortening of the G0/G1 and S phases of the cell cycle. In addition to the effects on cell growth, we found that elevated levels of Hsp70 were sufficient to confer a significant level of protection against heat in MCF-7 cells. The results of this study support existing evidence linking Hsp70 expression with cell growth and cytoprotection in human cancer cells.
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Affiliation(s)
- J A Barnes
- National Research Council, National Health and Environmental Effects Research Laboratory, Office of Research and Development, US Environmental Protection Agency, Research Triangle Park, NC 27711, USA.
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29
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Uehara T, Matsuzawa H, Nishimura A. HscA is involved in the dynamics of FtsZ-ring formation in Escherichia coli K12. Genes Cells 2001; 6:803-14. [PMID: 11554926 DOI: 10.1046/j.1365-2443.2001.00463.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND FtsZ, a homologue of eukaryotic tubulin, localizes throughout the cytoplasm in non-dividing Escherichia coli. However, it assembles in cytokinetic rings at the early stages of septation. Factors controlling the dynamics of FtsZ ring formation are unknown, and the molecular mechanism governing these dynamics is yet to be determined. RESULTS At 42 degrees C, JE10715 mutant bacteria formed multinucleated filaments with a highly reduced number of FtsZ-rings at potential division sites. The JE10715 phenotype resulted from a mis-sense mutation in the hscA gene which encodes a heat shock Hsp70 family protein, with a single alanine-to-valine substitution at position 192 within the ATPase domain. Both JE10715 and the hscA knockout strain of JE10715 were completely complemented by a plasmid-born, wild-type hscA gene, but not by a mutant-type hscA715 gene. An hscA conditional knockout of the wild-type strain under non-permissive conditions exhibited longer rod cells with an abnormal localization of FtsZ. The over-expression of dnaK partially complemented the JE10715 mutation. In vitro, the ATPase activity of the mutant protein HscA715 was reduced to 63% of wild-type HscA activity. HscA co-sedimented with FtsZ-polymers in the presence of GTP. CONCLUSION HscA is involved in FtsZ-ring formation, through a chaperon-like interaction with FtsZ. Defects in hscA, however, can partially be compensated for by redundant genes, including the wild-type dnaK.
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Affiliation(s)
- T Uehara
- National Institute of Genetics, Mishima, Shizuoka-ken 411-8540, Japan
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30
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Byrd CA, Bornmann W, Erdjument-Bromage H, Tempst P, Pavletich N, Rosen N, Nathan CF, Ding A. Heat shock protein 90 mediates macrophage activation by Taxol and bacterial lipopolysaccharide. Proc Natl Acad Sci U S A 1999; 96:5645-50. [PMID: 10318938 PMCID: PMC21914 DOI: 10.1073/pnas.96.10.5645] [Citation(s) in RCA: 169] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Taxol, a plant-derived antitumor agent, stabilizes microtubules. Taxol also elicits cell signals in a manner indistinguishable from bacterial lipopolysaccharide (LPS). LPS-like actions of Taxol are controlled by the lps gene and are independent of binding to the known Taxol target, beta-tubulin. Using biotin-labeled Taxol, avidin-agarose affinity chromatography, and peptide mass fingerprinting, we identified two Taxol targets from mouse macrophages and brain as heat shock proteins (Hsps) of the 70- and 90-kDa families. Geldanamycin, a specific inhibitor of the Hsp 90 family, blocked the nuclear translocation of NF-kappaB and expression of tumor necrosis factor in macrophages treated with Taxol or with LPS. Geldanamycin did not block microtubule bundling by Taxol or macrophage activation by tumor necrosis factor. Thus, Taxol binds Hsps, and Hsp 90 helps mediate the activation of macrophages by Taxol and by LPS.
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Affiliation(s)
- C A Byrd
- Departments of Microbiology and Immunology, and Medicine, Weill Medical College of Cornell University, New York, NY 10021, USA
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Roobol A, Sahyoun ZP, Carden MJ. Selected subunits of the cytosolic chaperonin associate with microtubules assembled in vitro. J Biol Chem 1999; 274:2408-15. [PMID: 9891010 DOI: 10.1074/jbc.274.4.2408] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The molecular chaperone activities of the only known chaperonin in the eukaryotic cytosol (cytosolic chaperonin containing T-complex polypeptide 1 (CCT)) appear to be relatively specialized; the main folding substrates in vivo and in vitro are identified as tubulins and actins. CCT is unique among chaperonins in the complexity of its hetero-oligomeric structure, containing eight different, although related, gene products. In addition to their known ability to bind to and promote correct folding of newly synthesized and denatured tubulins, we show here that CCT subunits alpha, gamma, zeta, and theta also associated with in vitro assembled microtubules, i.e. behaved as microtubule-associated proteins. This nucleotide-dependent association between microtubules and CCT polypeptides (Kd approximately 0.1 microM CCT subunit) did not appear to involve whole oligomeric chaperonin particles, but rather free CCT subunits. Removal of the tubulin COOH termini by subtilisin digestion caused all eight CCT subunits to associate with the microtubule polymer, thus highlighting the non-chaperonin nature of the selective CCT subunit association with normal microtubules.
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Affiliation(s)
- A Roobol
- Department of Biosciences, University of Kent, Canterbury, Kent CT2 7NJ, United Kingdom.
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Wang H, Bedford FK, Brandon NJ, Moss SJ, Olsen RW. GABA(A)-receptor-associated protein links GABA(A) receptors and the cytoskeleton. Nature 1999; 397:69-72. [PMID: 9892355 DOI: 10.1038/16264] [Citation(s) in RCA: 538] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Type-A receptors for the neurotransmitter GABA (gamma-aminobutyric acid) are ligand-gated chloride channels that mediate inhibitory neurotransmission. Each subunit of the pentameric receptor protein has ligand-binding sites in the amino-terminal extracellular domain and four membrane-spanning regions, one of which forms a wall of the ion channel. Each subunit also has a large intracellular loop that may be a target for protein kinases and be required for subcellular targeting and membrane clustering of the receptor, perhaps by anchoring the receptor to the cytoskeleton. Neurotransmitter receptors need to be positioned in high density in the cell membrane at sites postsynaptic to nerve terminals releasing that neurotransmitter. Other members of the superfamily of ligand-gated ion-channel receptors associate in postsynaptic-membrane clusters by binding to the proteins rapsyn or gephyrin. Here we identify a new cellular protein, GABA(A)-receptor-associated protein (GABARAP), which can interact with the gamma2 subunit of GABA(A) receptors. GABARAP binds to GABA(A) receptors both in vitro and in vivo, and co-localizes with the punctate staining of GABA(A) receptors on cultured cortical neurons. Sequence analysis shows similarity between GABARAP and light chain-3 of microtubule-associated proteins 1A and 1B. Moreover, the N terminus of GABARAP is highly positively charged and features a putative tubulin-binding motif. The interactions among GABA(A) receptors, GABARAP and tubulin suggest a mechanism for the targeting and clustering of GABA(A) receptors.
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Affiliation(s)
- H Wang
- Molecular Biology Institute, University of California, Los Angeles 90095, USA
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33
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Bluhm WF, Martin JL, Mestril R, Dillmann WH. Specific heat shock proteins protect microtubules during simulated ischemia in cardiac myocytes. THE AMERICAN JOURNAL OF PHYSIOLOGY 1998; 275:H2243-9. [PMID: 9843825 DOI: 10.1152/ajpheart.1998.275.6.h2243] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The protective effects of heat shock proteins (HSPs) during myocardial ischemia are now well documented, but little is known about the mechanisms of protection and the specificity of different HSPs. Because cytoskeletal injury plays a crucial role in the pathogenesis of irreversible ischemic damage, we tested whether overexpression of specific HSPs protects the integrity of microtubules during simulated ischemia in rat neonatal cardiac myocytes. Overexpression of specific HSPs was achieved by adenovirus-mediated transgene expression. Damage was assessed by comparing control cells to cells that were subjected to a simulated ischemia protocol. Microtubular integrity was measured by indirect immunofluorescence, confocal microscopy, and image analysis. Within 14 h of simulated ischemia, microtubular integrity decreased significantly in uninfected myocytes (from 24.6 +/- 1.2 to 13.2 +/- 0.4) and in myocytes infected with a control virus that expressed no transgene (from 25.9 +/- 1.8 to 13.1 +/- 1.4). Microtubular integrity after ischemia was significantly better preserved in cells overexpressing constitutive Hsp70 (21.7 +/- 1.6) or alphaB-crystallin (18.0 +/- 2.7) but not in cells overexpressing inducible Hsp70 (11.5 +/- 0.8) or Hsp27 (14.0 +/- 2.2). We conclude that specific HSPs protect the microtubules during simulated cardiac ischemia.
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Affiliation(s)
- W F Bluhm
- Department of Medicine, Division of Endocrinology and Metabolism, University of California, San Diego, La Jolla, California 92093-0618, USA
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Oka M, Nakai M, Endo T, Lim CR, Kimata Y, Kohno K. Loss of Hsp70-Hsp40 chaperone activity causes abnormal nuclear distribution and aberrant microtubule formation in M-phase of Saccharomyces cerevisiae. J Biol Chem 1998; 273:29727-37. [PMID: 9792686 DOI: 10.1074/jbc.273.45.29727] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The 70-kDa heat shock proteins, hsp70, are highly conserved among both prokaryotes and eukaryotes, and function as chaperones in diverse cellular processes. To elucidate the function of the yeast cytosolic hsp70 Ssa1p in vivo, we characterized a Saccharomyces cerevisiae ssa1 temperature-sensitive mutant (ssa1-134). After shifting to the restrictive temperature (37 degreesC), ssa1-134 mutant cells showed abnormal distribution of nuclei and accumulated as large-budded cells with a 2 N DNA content. We observed more prominent mutant phenotypes using nocodazole-synchronized cells: when cells were incubated at the restrictive temperature following nocodazole treatment, viability was rapidly lost and abnormal arrays of bent microtubules were formed. Chemical cross-linking and immunoprecipitation analyses revealed that the interaction of mutant Ssa1p with Ydj1p (cytosolic DnaJ homologue in yeast) was much weaker compared with wild-type Ssa1p. These results suggest that Ssa1p and Ydj1p chaperone activities play important roles in the regulation of microtubule formation in M phase. In support of this idea, a ydj1 null mutant at the restrictive temperature was found to exhibit more prominent phenotypes than ssa1-134. Furthermore, both ssa1-134 and ydj1 null mutant cells exhibited greater sensitivity to anti-microtubule drugs. Finally, the observation that SSA1 and YDJ1 interact genetically with a gamma-tubulin, TUB4, supports the idea that they play a role in the regulation of microtubule formation.
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Affiliation(s)
- M Oka
- Research and Education Center for Genetic Information, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0101, Japan
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35
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Garnier C, Barbier P, Gilli R, Lopez C, Peyrot V, Briand C. Heat-shock protein 90 (hsp90) binds in vitro to tubulin dimer and inhibits microtubule formation. Biochem Biophys Res Commun 1998; 250:414-9. [PMID: 9753644 DOI: 10.1006/bbrc.1998.9319] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Hsp90 interacts with steroid hormone receptors, protein kinases, and cytoskeletal proteins. The mode of action of hsp90 on microtubules and tubulin has not been investigated. Using isolated purified hsp90 and isolated tubulin, we demonstrated in vitro by difference absorption and fluorescence spectroscopy that hsp90 bound to tubulin with an apparent affinity constant of 5 x 10(5) M-1, assuming an apparent stoichiometry of 1 at 25 degrees C. Using microcalorimetry, we found a delta H of -9.8 +/- 0.8 kJ.mol-1. The binding of hsp90 to tubulin was confirmed by a sedimentation assay. Moreover, we showed that hsp90 inhibited tubulin polymerisation.
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Affiliation(s)
- C Garnier
- Faculté de Pharmacie, UPRESA CNRS 6032, Marseille, France
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36
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Platelet Adhesion to Collagen Under Flow Causes Dissociation of a Phosphoprotein Complex of Heat-Shock Proteins and Protein Phosphatase 1. Blood 1997. [DOI: 10.1182/blood.v90.4.1516.1516_1516_1526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Phosphorylation/dephosphorylation events in human blood platelets were investigated during their adhesion to collagen under flow conditions. Using 32P-labeled platelets and one-dimensional gel electrophoresis, we found that adhesion to collagen mediated primarily by the α2β1 integrin resulted in a strong dephosphorylation of several protein bands. Neither adhesion to polylysine nor thrombin-induced aggregation caused similar protein dephosphorylation. In addition, treatment with okadaic acid (OA), an inhibitor of serine/threonine protein phosphatases type 1 (PP1) and 2A (PP2A), caused significant inhibition of adhesion, suggesting that adhesion is regulated by OA-sensitive phosphatases. Recent studies indicate that phosphatases may be associated with the heat-shock proteins. Immunoprecipitations with antibodies against either the heat-shock cognate protein 70 (hsc70) or heat-shock protein 90 (hsp90) showed the presence of a phosphoprotein complex in 32P-labeled, resting human platelets. Antibody probing of this complex detected hsc70, hsp90, two isoforms of the catalytic subunit of PP1, PP1Cα and PP1Cδ, as well as the M regulatory subunit of PP1 (PP1M). OA, at concentrations that markedly blocked platelet adhesion to collagen, caused hyperphosphorylation of the hsc70 complex. In platelets adhering to collagen, hsc70 was completely dephosphorylated and hsp90, PP1α, and PP1M were dissociated from the complex, suggesting involvement of heat-shock proteins and protein phosphatases in platelet adhesion.
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37
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Platelet Adhesion to Collagen Under Flow Causes Dissociation of a Phosphoprotein Complex of Heat-Shock Proteins and Protein Phosphatase 1. Blood 1997. [DOI: 10.1182/blood.v90.4.1516] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AbstractPhosphorylation/dephosphorylation events in human blood platelets were investigated during their adhesion to collagen under flow conditions. Using 32P-labeled platelets and one-dimensional gel electrophoresis, we found that adhesion to collagen mediated primarily by the α2β1 integrin resulted in a strong dephosphorylation of several protein bands. Neither adhesion to polylysine nor thrombin-induced aggregation caused similar protein dephosphorylation. In addition, treatment with okadaic acid (OA), an inhibitor of serine/threonine protein phosphatases type 1 (PP1) and 2A (PP2A), caused significant inhibition of adhesion, suggesting that adhesion is regulated by OA-sensitive phosphatases. Recent studies indicate that phosphatases may be associated with the heat-shock proteins. Immunoprecipitations with antibodies against either the heat-shock cognate protein 70 (hsc70) or heat-shock protein 90 (hsp90) showed the presence of a phosphoprotein complex in 32P-labeled, resting human platelets. Antibody probing of this complex detected hsc70, hsp90, two isoforms of the catalytic subunit of PP1, PP1Cα and PP1Cδ, as well as the M regulatory subunit of PP1 (PP1M). OA, at concentrations that markedly blocked platelet adhesion to collagen, caused hyperphosphorylation of the hsc70 complex. In platelets adhering to collagen, hsc70 was completely dephosphorylated and hsp90, PP1α, and PP1M were dissociated from the complex, suggesting involvement of heat-shock proteins and protein phosphatases in platelet adhesion.
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38
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Abstract
Many kinds of injuries induce 72 kDa heat-shock protein (HSP70) in the central nervous system. We investigated the role of HSP70 in promoting the survival of rat hippocampal neurons in primary culture. Heat-shock (42 degrees C for 30 min) significantly increased the number of surviving neurons independently of the initial density of plated cells, suggesting a direct effect on the neurons. Immunohistochemical detection revealed that HSP70 was expressed in virtually all cells six hours after the heat-shock and the immunostaining became stronger during the observation period of 72 h. HSP70 immunoreactivity was localized in the nucleus at 24 h after the heat-shock, but was diffused throughout the cytoplasm at 72 h. Addition of an antisense oligonucleotide to the medium significantly suppressed the neuroprotective effect of the heat-shock to control level, while a sense oligonucleotide had no effect. HSP70 immunoreactivity was completely abolished in the presence of the antisense oligonucleotide. These results indicate that HSP70 is essential for neuroprotection by heat-shock.
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Affiliation(s)
- K Sato
- Department of Chemical Pharmacology, Faculty of Pharmaceutical Sciences, University of Tokyo, Japan
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39
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Zabala JC, Fontalba A, Avila J. Tubulin folding is altered by mutations in a putative GTP binding motif. J Cell Sci 1996; 109 ( Pt 6):1471-8. [PMID: 8799834 DOI: 10.1242/jcs.109.6.1471] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Tubulins contain a glycine-rich loop, that has been implicated in microtubule dynamics by means of an intramolecular interaction with the carboxy-terminal region. As a further extension of the analysis of the role of the carboxy-terminal region in tubulin folding we have mutated the glycine-rich loop of tubulin subunits. An alpha-tubulin point mutant with a T150-->G substitution (the corresponding residue present in beta-tubulin) was able to incorporate into dimers and microtubules. On the other hand, four beta-tubulin point mutants, including the G148-->T substitution, did not incorporate into dimers, did not release monomers, but were able to form C900 and C300 complexes (intermediates in the process of tubulin folding). Three other mutants within this region (which approximately encompasses residues 137–152) were incapable of forming dimers and C300 complexes but gave rise to the formation of C900 complexes. These results suggest that tubulin goes through two sequential folding states during the folding process, first in association with TCP1-complexes (C900) prior to the transfer to C300 complexes. It is this second step that implies binding/hydrolysis of GTP, reinforcing our previous proposed model for tubulin folding and assembly.
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Affiliation(s)
- J C Zabala
- Departamento de Biologia Molecular, Facultad de Medicina, Universidad de Cantabria, Spain
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40
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Bloch MA, Johnson KA. Identification of a molecular chaperone in the eukaryotic flagellum and its localization to the site of microtubule assembly. J Cell Sci 1995; 108 ( Pt 11):3541-5. [PMID: 8586665 DOI: 10.1242/jcs.108.11.3541] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Monoclonal antibodies that recognize HSP70 family members from evolutionarily divergent organisms were used to identify both constitutively-expressed and stress-inducible HSP70 proteins in the green alga Chlamydomonas. These monoclonal antibodies also cross-reacted with a 70 kDa flagellar protein that comigrated with the constitutively-expressed HSP70 isoform(s) present in the cell body; this is the first identification of a molecular chaperone within the eukaryotic flagellum. Fractionation experiments demonstrated that much of the flagellar HSP70 was bound to the ‘9+2’ microtubule axoneme. Incubation of isolated axonemes in ATP, but not AMP or AMP-PNP, caused significant release of the previously bound HSP70 as is characteristic of complexed HSP70s. Immunofluorescent localization in whole flagella showed that flagellar HSP70 was concentrated at the distal ends of flagella, sites of axonemal assembly in vivo. Extraction of axonemes under ionic conditions known to cause the release of capping structures that link the distal ends of the axonemal microtubules to the flagellar membrane also caused the release of axonemal-bound HSP70. Taken together, these results suggest a model in which an HSP70 chaperone may assist in targeting tubulin and other unassembled axonemal components to the flagellar tip where the chaperone may also participate in the assembly of the ‘9+2’ flagellar axoneme.
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Affiliation(s)
- M A Bloch
- Department of Molecular, Cellular and Developmental Biology, Haverford College, PA 19041, USA
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41
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42
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Silva NL, Haworth RS, Singh D, Fliegel L. The carboxyl-terminal region of the Na+/H+ exchanger interacts with mammalian heat shock protein. Biochemistry 1995; 34:10412-20. [PMID: 7654695 DOI: 10.1021/bi00033a013] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
We expressed the carboxyl-terminal 178 amino acids of the rabbit cardiac Na+/H+ exchanger as a fusion protein with glutathione-S-transferase. The fusion protein (PCR178) was found in the supernatant of extracts of E. coli and was purified using Glutathione-Sepharose affinity chromatography. Affinity-purified antibodies raised against the carboxyl-terminal region of the Na+/H+ exchanger identified the resultant protein. PCR178 copurified with a 70 kDa protein. Amino-terminal sequencing of the 70 kDa protein identified it as dnaK, the bacterial equivalent of the mammalian 70 kDa heat shock protein (hsp70). DnaK was dissociated from the Na+/H+ exchanger fusion protein by the addition of MgATP. When purified PCR178 was coupled to a cyanogen bromide-activated Sepharose column, bovine hsp70 bound to the column and was eluted with MgATP. Nondenaturing polyacrylamide gel electrophoresis showed that, in the absence of MgATP, hsp70 formed a complex with PCR178. The complex was dissociated by the addition of MgATP. GST alone did not form a complex with hsp70. Immunoprecipitation of the Na+/H+ exchanger with antiexchanger antibodies resulted in coprecipitation of hsp70 protein from antiporter containing cells. Cells that overexpress the Na+/H+ exchanger had increased amounts of hsp70 which coprecipitated with antiexchanger antibody. The results show that heat shock protein complexes with the mammalian Na+/H+ exchanger.
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Affiliation(s)
- N L Silva
- Department of Biochemistry, University of Alberta, Edmonton, Canada
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43
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Sharma HS, Olsson Y, Westman J. A serotonin synthesis inhibitor, p-chlorophenylalanine reduces the heat shock protein response following trauma to the spinal cord: an immunohistochemical and ultrastructural study in the rat. Neurosci Res 1995; 21:241-9. [PMID: 7753505 DOI: 10.1016/0168-0102(94)00855-a] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The influence of the serotonin synthesis inhibitor, p-CPA on the expression of the heat shock protein (70 kDa), which occurs around an injury to the rat spinal cord, was examined by immunohistochemistry. A longitudinal incision was made into the right dorsal horn at the T10-11 level. Five hours later samples were removed from the T9 and T12 segments. Samples from untreated traumatised animals showed signs of edema and many distorted neurons, particularly in the ipsilateral grey matter. Neurons of the same regions showed a profound increase in HSP-70 immunostaining compared with intact controls. At ultrastructural level, the immunoreactivity was detected in neuronal cytoplasm attached to the surface of organelles including endoplasmic reticulum, in the nucleus and in dendrites. Other groups of rats were given p-CPA before injury to reduce the synthesis of serotonin and to minimise its stores in the cord. The HSP-immunostaining in neurons of the T9 and T12 segments of the spinal cord was virtually lacking in the drug treated animals. The signs of edema and the structural changes of these segments were markedly reduced. The results show that inhibition of serotonin synthesis prior to the traumatic insult has an inhibitory influence on HSP response occurring in neurons around the site of injury to the spinal cord, not reported earlier.
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Affiliation(s)
- H S Sharma
- Laboratory of Neuropathology, University Hospital, University of Uppsala, Sweden
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44
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Neesen J, Padmanabhan S, Bünemann H. Tandemly arranged repeats of a novel highly charged 16-amino-acid motif representing the major component of the sperm-tail-specific axoneme-associated protein family Dhmst101 form extended alpha-helical rods within the extremely elongated spermatozoa of Drosophila hydei. EUROPEAN JOURNAL OF BIOCHEMISTRY 1994; 225:1089-95. [PMID: 7957199 DOI: 10.1111/j.1432-1033.1994.1089b.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
We have previously reported that the sperm-tail-specific proteins in Drosophila hydei, encoded by the small Dhmst101 gene family, contained several tandem repeats of a novel highly charged, well-conserved cysteine-containing motif of 16 amino acids, KKKCAEAAKKEKEAAE [Neesen, J., Bünemann, H. & Heinlein, U. A. O. (1994) Dev. Biol. 162, 414-425] and suggested that this motif might be important in the structural and functional integrity of the sperm tail. We tested this suggestion by examining structure formation by model synthetic peptides containing the 16-residue sequence and corresponding peptides with one and two repeats of the sequence with Cys being replaced by Ala. We find that all these peptides form monomeric alpha-helices and that the helix content is considerably enhanced as the number of tandem repeats increases. These results are consistent with tandemly arranged 16-amino-acid repeats in Dhmst101 proteins forming extended alpha-helical rods, with the highly conserved Cys present in each 16-amino-acid motif being involved in regular interhelical cross-linking, thus providing a rigid, stable framework within the extremely elongated spermatozoa of Drosophila hydei.
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Affiliation(s)
- J Neesen
- Institute for Human Genetics, University of Göttingen, Germany
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