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Usman S, Aldehlawi H, Nguyen TKN, Teh MT, Waseem A. Impact of N-Terminal Tags on De Novo Vimentin Intermediate Filament Assembly. Int J Mol Sci 2022; 23:ijms23116349. [PMID: 35683030 PMCID: PMC9181571 DOI: 10.3390/ijms23116349] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 06/02/2022] [Accepted: 06/04/2022] [Indexed: 02/01/2023] Open
Abstract
Vimentin, a type III intermediate filament protein, is found in most cells along with microfilaments and microtubules. It has been shown that the head domain folds back to associate with the rod domain and this association is essential for filament assembly. The N-terminally tagged vimentin has been widely used to label the cytoskeleton in live cell imaging. Although there is previous evidence that EGFP tagged vimentin fails to form filaments but is able to integrate into a pre-existing network, no study has systematically investigated or established a molecular basis for this observation. To determine whether a tag would affect de novo filament assembly, we used vimentin fused at the N-terminus with two different sized tags, AcGFP (239 residues, 27 kDa) and 3 × FLAG (22 residues; 2.4 kDa) to assemble into filaments in two vimentin-deficient epithelial cells, MCF-7 and A431. We showed that regardless of tag size, N-terminally tagged vimentin aggregated into globules with a significant proportion co-aligning with β-catenin at cell–cell junctions. However, the tagged vimentin aggregates could form filaments upon adding untagged vimentin at a ratio of 1:1 or when introduced into cells containing pre-existing filaments. The resultant filament network containing a mixture of tagged and untagged vimentin was less stable compared to that formed by only untagged vimentin. The data suggest that placing a tag at the N-terminus may create steric hinderance in case of a large tag (AcGFP) or electrostatic repulsion in case of highly charged tag (3 × FLAG) perhaps inducing a conformational change, which deleteriously affects the association between head and rod domains. Taken together our results shows that a free N-terminus is essential for filament assembly as N-terminally tagged vimentin is not only incapable of forming filaments, but it also destabilises when integrated into a pre-existing network.
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Affiliation(s)
- Saima Usman
- Centre for Oral Immunobiology and Regenerative Medicine, Institute of Dentistry, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, Newark Street, London E1 2AT, UK; (S.U.); (T.K.N.N.); (M.-T.T.)
| | - Hebah Aldehlawi
- Department of Oral Diagnostic Sciences, Division of Oral Pathology and Medicine, Faculty of Dentistry, King Abdul Aziz University, Jeddah 21589, Saudi Arabia;
| | - Thuan Khanh Ngoc Nguyen
- Centre for Oral Immunobiology and Regenerative Medicine, Institute of Dentistry, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, Newark Street, London E1 2AT, UK; (S.U.); (T.K.N.N.); (M.-T.T.)
| | - Muy-Teck Teh
- Centre for Oral Immunobiology and Regenerative Medicine, Institute of Dentistry, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, Newark Street, London E1 2AT, UK; (S.U.); (T.K.N.N.); (M.-T.T.)
| | - Ahmad Waseem
- Centre for Oral Immunobiology and Regenerative Medicine, Institute of Dentistry, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, Newark Street, London E1 2AT, UK; (S.U.); (T.K.N.N.); (M.-T.T.)
- Centre for Immunobiology and Regenerative Medicine, Blizard Institute, 4 Newark Street, London E1 2AT, UK
- Correspondence: ; Tel.: +44-207-882-2387; Fax: +44-207-882-7137
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Gavrilova LP, Korpacheva II, Semushina SG, Yashin VA. Heat shock induces simultaneous rearrangements of all known cytoskeletal filaments in normal interphase fibroblasts. ACTA ACUST UNITED AC 2013. [DOI: 10.1134/s1990519x13010045] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Hyperthermia induces cytoskeletal alterations and mitotic catastrophe in p53-deficient H1299 lung cancer cells. Acta Histochem 2013; 115:8-15. [PMID: 22483983 DOI: 10.1016/j.acthis.2012.02.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Revised: 02/21/2012] [Accepted: 02/23/2012] [Indexed: 02/07/2023]
Abstract
Hyperthermia is used in cancer therapy, however much remains to be discovered regarding its mechanisms of action at the cellular level. In this study, the effects of hyperthermia on cell death, survival, morphology and the cytoskeleton were investigated in a non-small cell lung cancer cell line, H1299. Despite the fact that this cell line is widely used in research, it has not yet been tested for heat shock sensitivity. Cells were given a 30-min heat shock at 43.5°C and 45°C and left to recover at 37°C for 24 and 48 h. 24 h after heat shock treatment, we monitored changes in the organization of the cytoskeleton using immunofluorescence microscopy. The number of actin stress fibers was significantly reduced, microtubules formed a looser meshwork, a portion of the cells possessed multipolar mitotic spindles, whereas vimentin filaments collapsed into perinuclear complexes. 48 h following heat stress, most of the cells showed recovery of the cytoskeleton, however we observed a considerable number of giant cells that were multinucleated or contained one enlarged nucleus. The data obtained by MTT assay showed a dose-dependent decrease of cell viability, while flow cytometric analysis revealed an increase in the number of cells with externalized phosphatidylserine. The results suggest that one of the modes of heat-induced cell death in H1299 cells is mitotic catastrophe, which probably ends in apoptosis.
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Chong KY, Lai CC, Su CY. Inducible and constitutive HSP70s confer synergistic resistance against metabolic challenges. Biochem Biophys Res Commun 2012. [PMID: 23206709 DOI: 10.1016/j.bbrc.2012.11.072] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Chaperonic proteins, including inducible HSP70 (HSP70i) and constitutive HSP70 (HSC70), have been implicated as essential players in the cellular adaptive protection. Ensuing studies demonstrated that overexpression of either protein individually protects against thermal and oxidative challenges. The present study aimed to determine whether a concurrent overexpression of both HSC70 and HSP70i confers a better metabolic protection than the expression of each protein alone. Using a rat heart-derived H9c2 cardiac myoblast cell line, we found that HSP70i was rapidly induced within 2-8h following a mild thermal preconditioning (43°C for 20 min) in both parental cells and an established H9/70c clonal sub-line overexpressing HSC70. The level of HSP70i protein in heat pretreated H9/70c clonal cells reached only 50% of that in heat pretreated H9c2 parental cells. Nevertheless, protection against lethal hyperthermia, menadione (an oxidant) and hydrogen peroxide (H(2)O(2)) exposure in the pretreated H9/70c clonal cells was significantly higher than the sum of protection afforded by the early induction of HSP70i in the pretreated parental cells and protection afforded by the pre-existing HSC70 in the H9/70c cells without preconditioning. Using dosimetric analysis, we also found that menadione resistance in the pretreated parental cells increased linearly with cellular HSP70i level (10-300 ng/mg total protein). However, the resistance in the pretreated H9/70c cells showed a biphasic relationship with cellular HSP70i level; when HSP70i concentration reached >250 ng/mg protein, survivability after menadione exposure was markedly enhanced. Similar results were observed in H9c2 cells genetically manipulated to overexpress both HSC70 and HSP70i. The survival benefit against lethal hyperthermia, oxidant treatment, and hypoxia/reoxygenation conferred by a concerted HSC70 and HSP70i overexpression was greater than the sum of benefits contributed by individual protein overexpression. Together, these findings suggest that HSC70 and HSP70i may complement each other in a synergistic manner to preserve cellular integrity during metabolic challenges.
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Affiliation(s)
- Kowit Yu Chong
- Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University, Tao-Yuan, Taiwan, ROC.
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5
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Satelli A, Li S. Vimentin in cancer and its potential as a molecular target for cancer therapy. Cell Mol Life Sci 2011; 68:3033-46. [PMID: 21637948 PMCID: PMC3162105 DOI: 10.1007/s00018-011-0735-1] [Citation(s) in RCA: 1044] [Impact Index Per Article: 80.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2011] [Revised: 05/12/2011] [Accepted: 05/16/2011] [Indexed: 02/06/2023]
Abstract
Vimentin, a major constituent of the intermediate filament family of proteins, is ubiquitously expressed in normal mesenchymal cells and is known to maintain cellular integrity and provide resistance against stress. Vimentin is overexpressed in various epithelial cancers, including prostate cancer, gastrointestinal tumors, tumors of the central nervous system, breast cancer, malignant melanoma, and lung cancer. Vimentin's overexpression in cancer correlates well with accelerated tumor growth, invasion, and poor prognosis; however, the role of vimentin in cancer progression remains obscure. In recent years, vimentin has been recognized as a marker for epithelial-mesenchymal transition (EMT). Although EMT is associated with several tumorigenic events, vimentin's role in the underlying events mediating these processes remains unknown. By virtue of its overexpression in cancer and its association with tumor growth and metastasis, vimentin serves as an attractive potential target for cancer therapy; however, more research would be crucial to evaluate its specific role in cancer. Our recent discovery of a vimentin-binding mini-peptide has generated further impetus for vimentin-targeted tumor-specific therapy. Furthermore, research directed toward elucidating the role of vimentin in various signaling pathways would reveal new approaches for the development of therapeutic agents. This review summarizes the expression and functions of vimentin in various types of cancer and suggests some directions toward future cancer therapy utilizing vimentin as a potential molecular target.
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Affiliation(s)
- Arun Satelli
- Department of Pediatrics, Unit 853, The University of Texas MD Anderson Cancer Center, 1515 Holocombe Blvd, Houston, TX 77030 USA
| | - Shulin Li
- Department of Pediatrics, Unit 853, The University of Texas MD Anderson Cancer Center, 1515 Holocombe Blvd, Houston, TX 77030 USA
- UTMD, Graduate School of Biomedical Science, Houston, TX 77030 USA
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6
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Intermediate filaments take the heat as stress proteins. Trends Cell Biol 2010; 20:79-91. [PMID: 20045331 DOI: 10.1016/j.tcb.2009.11.004] [Citation(s) in RCA: 193] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2009] [Revised: 11/13/2009] [Accepted: 11/17/2009] [Indexed: 11/18/2022]
Abstract
Intermediate filament (IF) proteins and heat shock proteins (HSPs) are large multimember families that share several features, including protein abundance, significant upregulation in response to a variety of stresses, cytoprotective functions, and the phenocopying of several human diseases after IF protein or HSP mutation. We are now coming to understand that these common elements point to IFs as important cellular stress proteins with some roles akin to those already well-characterized for HSPs. Unique functional roles for IFs include protection from mechanical stress, whereas HSPs are characteristically involved in protein folding and as chaperones. Shared IF and HSP cytoprotective roles include inhibition of apoptosis, organelle homeostasis, and scaffolding. In this report, we review data that corroborate the view that IFs function as highly specialized cytoskeletal stress proteins that promote cellular organization and homeostasis.
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Turturici G, Geraci F, Candela ME, Giudice G, Gonzalez F, Sconzo G. Hsp70 localizes differently from chaperone Hsc70 in mouse mesoangioblasts under physiological growth conditions. J Mol Histol 2008; 39:571-8. [DOI: 10.1007/s10735-008-9197-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2008] [Accepted: 09/16/2008] [Indexed: 10/21/2022]
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Ellis S, Killender M, Anderson RL. Heat-induced alterations in the localization of HSP72 and HSP73 as measured by indirect immunohistochemistry and immunogold electron microscopy. J Histochem Cytochem 2000; 48:321-32. [PMID: 10681386 DOI: 10.1177/002215540004800302] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The heat shock proteins are a family of stress-inducible proteins that act as molecular chaperones for nascent proteins and assist in protection and repair of proteins whose conformation is altered by stress. HSP72 and HSP73 are two major cytosolic/nuclear stress proteins of mammalian cells, with extensive sequence homology. HSP73 is constitutively expressed, whereas HSP72 is highly stress-inducible. However, it is unclear why two isoforms are expressed and whether these two proteins have different functions in the cell. To assist in the delineation of function, we have completed a detailed study of the localization of HSP72 and HSP73 in the cell before and after heat stress, using two different methods of detection. By indirect immunohistochemistry, the localization of these two proteins is similar, cytoplasmic and nuclear in nonstressed cells with a translocation to nucleoli immediately after heat. By the more sensitive immunogold electron microscopy technique, differences in localization were noted. In nonstressed cells, HSP72 was primarily nuclear, localized in heterochromatic regions and in nucleoli. HSP73 was distributed throughout the cell, with most cytoplasmic label associated with mitochondria. Mitotic chromosomes were also heavily labeled. After stress, HSP72 concentrated in nuclei and nucleoli and HSP73 localized to nuclei, nucleoli, and cytoplasm, with increased label over mitochondria. These differences in localization suggest that the HSP72 and HSP73 may associate with different proteins or complexes and hence have different but overlapping functions in the cell.
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Affiliation(s)
- S Ellis
- Peter MacCallum Cancer Institute, Melbourne, Victoria, Australia
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Evans RM, Simpkins H. Cisplatin induced intermediate filament reorganization and altered mitochondrial function in 3T3 cells and drug-sensitive and -resistant Walker 256 cells. Exp Cell Res 1998; 245:69-78. [PMID: 9828102 DOI: 10.1006/excr.1998.4250] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cisplatin has acute but reversible effects on the organization of the intermediate filament component of the cytoskeleton as well as the mitochondrial function of cultured 3T3 cells. These effects do not involve major changes in total cell or cytoskeletal protein synthesis and appear to be distinct from the long-term cytotoxicity produced by the drug. Cells treated with similar concentrations of second-generation platinum compounds, which have reduced nephrotoxic effects in vivo, do not exhibit alterations in intermediate filament organization nor mitochondrial rhodamine 123 fluorescence. Similar studies with cisplatin-sensitive and -resistant lines of rat Walker 256 cells indicated that the drug-induced intermediate filament collapse and decreased mitochondrial rhodamine 123 fluorescence correlated with the susceptibility of these cells to the lethal effects of cisplatin.
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Affiliation(s)
- R M Evans
- Department of Pathology, University of Colorado Health Sciences Center, Denver, Colorado, 80262, USA
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10
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Hung JJ, Cheng TJ, Dah-Tsyr Chang M, Chen KD, Huang HL, Lai YK. Involvement of heat shock elements and basal transcription elements in the differential induction of the 70-kDa heat shock protein and its cognate by cadmium chloride in 9L rat brain tumor cells. J Cell Biochem 1998. [DOI: 10.1002/(sici)1097-4644(19981001)71:1<21::aid-jcb3>3.0.co;2-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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11
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Martín M, Hernández C, Bodega G, Suárez I, Boyano MC, Fernández B. Heat-shock proteins expression in fish central nervous system and its possible relation with water acidosis resistance. Neurosci Res 1998; 31:97-106. [PMID: 9700715 DOI: 10.1016/s0168-0102(98)00028-5] [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: 02/08/2023]
Abstract
The expression of 70 and 60-kDa heat-shock proteins (HSP70 and HSP60) and glial fibrillary acidic protein (GFAP), determined by immunoblotting and immunohistochemical methods, was studied in fish neural tissue; moreover the possible correlation between the expression of these proteins in neural tissue and fish acidosis resistance was also examined. The HSP GFAP content was analyzed in four different teleostean fish species (gourami, carp, goldfish and trout) under control conditions and in carp under experimental conditions to induce HSPs expression. Under control conditions, HSP70 and HSP60 expression was similar in gourami, carp and goldfish, but gourami had the highest acidosis resistance; trout had the lowest HSP70 and 60 expression and lowest acidosis resistance. The HSP expression pattern was mainly neuronal under control conditions. HSP expression was induced in carp and the effect of this induction on acidosis resistance was studied. Two methods were used for HSP induction in carp: acid shock (2 h at 4.5 pH) and heat shock (2 h at 33 degrees C). A high acidosis resistance, although non-significant, was observed after heat pretreatment. An important HSP expression was detected in glial cells after induction. GFAP expression showed no association with acidosis resistance under either control or experimental conditions.
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Affiliation(s)
- M Martín
- Departamento de Biología Celular y Genética, Universidad de Alcalá, Alcalá de Henares, Madrid, Spain
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Wang TT, Chiang AS, Chu JJ, Cheng TJ, Chen TM, Lai YK. Concomitant alterations in distribution of 70 kDa heat shock proteins, cytoskeleton and organelles in heat shocked 9L cells. Int J Biochem Cell Biol 1998; 30:745-59. [PMID: 9695029 DOI: 10.1016/s1357-2725(97)00133-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Maintenance of cell architecture and positioning of organelles are major functions of the cytoskeleton. On the other hand, induction of heat shock proteins (HSPs) and reorganization of the cytoskeleton are the most significant changes in heat-shocked mammalian cells. We examine the alterations in HSP70 and its constitutively expressed cognate, HSC70, as well as the cytoskeleton and organelles in 9L rat brain tumor cells upon heat shock. We employed fluorescence microscopy and scanning electron microscopy to follow these changes. Levels of HSP70s were quantified by Western blotting. Accumulation of HSC70 was more transient and the protein translocated to and subsequently exited from the nucleus more rapidly than HSP70. Changes in actin microfilaments include the nuclear localization of actin fraction and disappearance of cytoplasmic microfilament bundles, while the cortical actin microfilaments were almost unaffected. Furthermore, microtubules retracted slightly from the cell periphery but remained largely unchanged. In contrast, the intermediate filaments collapsed into the perinuclear region. The mitochondria converted from filamentous into granular forms and clustered in a region overlapping with the collapsed intermediate filaments. All of the above alterations are reversible and largely reverted after 8 h of recovery. The effect on Golgi organization was very transient and the apparatus assumed a normal appearance within 4 h after the heat treatment. The ER, on the other hand, was totally unaffected by the heat treatment. These observations help correlate the sequential events following a stress like heat shock and suggest possible physiological functions of these essential constituents of a cell under stress.
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Affiliation(s)
- T T Wang
- Department of Life Science, National Tsing Hua University, Hsinchu, Taiwan, Republic of China
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Cheng TJ, Chen TM, Chen CH, Lai YK. Induction of stress response and differential expression of 70 kDa stress proteins by sodium fluoride in HeLa and rat brain tumor 9L cells. J Cell Biochem 1998; 69:221-31. [PMID: 9548569 DOI: 10.1002/(sici)1097-4644(19980501)69:2<221::aid-jcb12>3.0.co;2-h] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
We herein demonstrate that sodium fluoride (NaF) acts as a stress response inducer on HeLa and 9L rat brain tumor cells. NaF is only slightly cytotoxic, and inhibitory to Ser/Thr-phosphatases but not to Tyr-phosphatases in both cell lines. After treatment with 5 mM NaF for 2 h, the phosphorylation levels of vimentin and an alkali-resistant 65-kDa phosphoprotein were enhanced, a common phenomenon detected in cells under a variety of stress conditions. Under an identical treatment protocol, in which the cells were treated with 5 mM NaF for 2 h and then allowed to recover under normal growing conditions for up to 12 h, NaF differentially induced the cytoplasmic/nuclear heat-shock protein70s (including both the inducible and the constitutively expressed members of this protein family) in HeLa cells and the endoplasmic reticulum residing heat-shock protein70 (the glucose-regulated protein with an apparent molecular weight of 78 kDa) in 9L cells. Electrophoretic mobility shift assays (EMSA) using probes containing well-characterized regulatory elements revealed the activation of the heat-shock factor in HeLa but not in 9L cells; this is in good agreement with the stress protein induction pattern. Additional differential induction of binding activities toward EMSA probes individually containing NF-KB, AP-2, and CRE-like elements were detected in NaF-treated cells. The possible involvement of these binding sites as well as the corresponding factors in the stress response are discussed.
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Affiliation(s)
- T J Cheng
- Department of Life Science, National Tsing Hua University, Hsinchu, Taiwan, Republic of China
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Chu JJ, Chen KD, Lin YL, Fei CY, Chiang AS, Chiang CD, Lai YK. Taxol induces concomitant hyperphosphorylation and reorganization of vimentin intermediate filaments in 9l rat brain tumor cells. J Cell Biochem 1998. [DOI: 10.1002/(sici)1097-4644(19980315)68:4<472::aid-jcb7>3.0.co;2-n] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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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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16
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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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Abstract
Exposure of cells and organs to heat shock is associated with numerous changes in various cellular metabolic parameters and overexpression of proteins collectively known as heat shock proteins (HSP). In this communication we review the cell-signaling events that are altered in response to heat shock as they relate to the subsequent induction of HSP 70 kd (HSP-70) expression. We also review the mechanisms by which HSP-70 is involved in conferring cytoprotective effects. The possibility of altering HSP expression through manipulations of the cell-signal process has clinical importance. Copyright 1996 S. Karger AG, Basel
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Affiliation(s)
- J. Gong Kiang
- Department of Clinical Physiology, Division of Medicine, Walter Reed Army Institute of Research, Washington, D.C., USA
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18
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Chen KD, Chu JJ, Lai YK. Modulation of protein phosphorylation and stress protein expression by okadaic acid on heat shock cells. J Cell Biochem 1996. [DOI: 10.1002/(sici)1097-4644(19960501)61:2<255::aid-jcb9>3.0.co;2-t] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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19
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Zachayus JL, Benatmane S, Plas C. Role of Hsp70 synthesis in the fate of the insulin-receptor complex after heat shock in cultured fetal hepatocytes. J Cell Biochem 1996; 61:216-29. [PMID: 9173085 DOI: 10.1002/(sici)1097-4644(19960501)61:2<216::aid-jcb5>3.0.co;2-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The influence of a mild heat shock on the fate of the insulin-receptor complex was studied in cultured fetal rat hepatocytes whose insulin glycogenic response is sensitive to heat [Zachayus and Plas (1995): J Cell Physiol 162:330-340]. After exposure from 15 min to 2 hr at 42.5 degrees C, the amount of (125)1-insulin associated with cells at 37 degrees C was progressively decreased (by 35% after 1 hr), while the release of (125)1-insulin degradation products into the medium was also inhibited (by 75%), more than expected from the decrease in insulin binding. Heat shock did not affect the insulin-induced internalization of cell surface insulin receptors but progressively suppressed the recycling at 37 degrees C of receptors previously internalized at 42.5 degrees C in the presence of insulin. When compared to the inhibitory effects of chloroquine on insulin degradation and insulin receptor recycling, which were immediate (within 15 min), those of heat shock developed within 1 hr of heating. The protein level of insulin receptors was not modified after heat shock and during recovery at 37 degrees C, while that of Hsp72/73 exhibited a transitory accumulation inversely correlated with variations in insulin binding, as assayed by Western immunoblotting from whole cell extracts. Coimmunoprecipitation experiments revealed a heat shock-stimulated association of Hsp72/73 with the insulin receptor. Affinity labeling showed an interaction between (125)1-insulin and Hsp72/73 in control cells, which was inhibited by heat shock. These results suggest that increased Hsp72/73 synthesis interfered with insulin degradation and prevented the recycling of the insulin receptor and its further thermal damage via a possible chaperone-like action in fetal hepatocytes submitted to heat stress.
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Affiliation(s)
- J L Zachayus
- Universite Paris, Institut Biomedical des Cordeliers, France
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20
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Chen KD, Chu JJ, Lai YK. Modulation of protein phosphorylation and stress protein expression by okadaic acid on heat shock cells. J Cell Biochem 1996; 61:255-65. [PMID: 9173089 DOI: 10.1002/(sici)1097-4644(19960501)61:2%3c255::aid-jcb9%3e3.0.co;2-t] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We have demonstrated that pretreatment but not post-treatment with okadaic acid (OA) can aggravate cytotoxicity as well as alter the kinetics of stress protein expression and protein phosphorylation in heat shocked cells. Compared to heat shock, cells recovering from 1 hr pretreatment of OA at 200 nM and cotreated with heat shock at 45 degrees C for the last 15 min of incubation (OA-->HS treatment) exhibited enhanced induction of heat shock proteins (HSPs) 70 and 110. In addition to enhanced expression, the attenuation of HSC70 and HSP90 after the induction peaks was also delayed in OA-->HS-treated cells. The above treatment also resulted in the rapid induction of the 78 kDa glucose-regulated protein (GRP78), which expression remained constant in cells recovering from treatment with 200 nM OA for 1 hr, heat shocked at 45 degrees C for 15 min, or in combined treatment in reversed order (HS-->OA treatment). Enhanced phosphorylation of vimentin and proteins with molecular weights of 65, 40, and 33 kDa and decreased phosphorylation of a protein with a molecular weight of 29 kDa were also observed in cells recovering from OA-->HS treatment. Again, protein phosphorylation in cells recovering from HS-->OA treatment did not differ from those in cells treated only with heat shock. Since the alteration in the kinetics of stress protein expression and protein phosphorylation was tightly correlated, we concluded that there is a critical link between induction of the stress proteins and phosphorylation of specific proteins. Furthermore, the rapid induction of GRP78 under the experimental condition offered a novel avenue for studying the regulation of its expression.
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Affiliation(s)
- K D Chen
- Department of Life Science, National Tsing Hua University, Hsinchu, Taiwan, Republic of China
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21
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Bensaude O, Bellier S, Dubois MF, Giannoni F, Nguyen VT. Heat-shock induced protein modifications and modulation of enzyme activities. EXS 1996; 77:199-219. [PMID: 8856976 DOI: 10.1007/978-3-0348-9088-5_13] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Upon heat stress, the cell physiology is profoundly altered. The extent of the alterations depends on the severity of the stress and may lead to cell death. The heat shock response is an array of metabolic changes characterized by the impairment of major cellular functions and by an adaptative reprogramming of the cell metabolism. The enhanced synthesis of the HSPs is a spectacular manifestation of this reprogramming. Numerous post translational modifications of proteins occur in response to heat stress and can be related to altered cellular functions. Some proteins are heat-denatured and temporarily inactivated. Heat-denaturation is reversible, chaperones may contribute to the repair. The extent of heat-denaturation depends on the cell metabolism: (a) it is attenuated in thermotolerant cells or in cells overexpressing the appropriate chaperones (b) it is enhanced in energy-deprived cells. Covalent modifications may also rapidly alter protein function. Changes in protein glycosylation, methylation, acetylation, farnesylation, ubiquitination have been found to occur during stress. But protein phosphorylation is the most studied modification. Several protein kinase cascades are activated, among which the various mitogen activated protein kinase (MAP kinase) cascades which are also triggered by a wide range of stimuli. As a possible consequence, stress modifies the phosphorylation status and the activity of components from the transcriptional and translational apparatuses. The same kinases also target key enzymes of the cellular metabolism. Protein denaturation results in constitutive hsp titration, this titration is a signal to trigger the heat-shock gene transcription and to activate some of the protein kinase cascades.
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Affiliation(s)
- O Bensaude
- Génétique Moléculaire, Ecole Normale Supérieure, Paris, France
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22
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Bousquet O, Basseville M, Vila-Porcile E, Billette de Villemeur T, Hauw JJ, Landrieu P, Portier MM. Aggregation of a subpopulation of vimentin filaments in cultured human skin fibroblasts derived from patients with giant axonal neuropathy. CELL MOTILITY AND THE CYTOSKELETON 1996; 33:115-29. [PMID: 8635201 DOI: 10.1002/(sici)1097-0169(1996)33:2<115::aid-cm4>3.0.co;2-b] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Giant axonal neuropathy (GAN) is a generalized disorder of intermediate filament networks which results in the formation of an ovoid aggregate in a large variety of cell types. We investigated the cytoskeletal organization of cultured skin fibroblasts derived from three GAN patients by indirect immunofluorescence, confocal, and electron microscopy. Whereas the organization of microfilaments seemed normal, the microtubule network appeared disorganized and tangled. The organization of the intermediate filament network, composed of vimentin, was probed with three antibodies directed against different epitopes: two vimentin-specific antibodies, a monoclonal antibody (mAb V9) and a polyclonal antibody, and a serum specific for all type III IFPs (PI serum). These experiments showed that 20% of cultured skin fibroblasts from GAN patients have a vimentin aggregate composed of densely packed filaments which coexists with a well-organized vimentin network. After depolymerization of microtubules with nocodazole, all fibroblasts from GAN patients contained a vimentin aggregate which seemed to arise from a subpopulation of vimentin filaments normally integrated in the vimentin network. Such aggregates were never observed in any condition in control fibroblasts. Moreover, the ultrastructural analysis of GAN cells revealed the presence of swollen mitochondria. We suggest that GAN may be due to a defect in a factor which stabilizes cytoplasmic intermediate filament networks, and we speculate on its identification and properties.
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Affiliation(s)
- O Bousquet
- Laboratoire de Biochimie Cellulaire, Collège de France, Paris
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Lee YC, Lai YK. Integrity of intermediate filaments is associated with the development of acquired thermotolerance in 9L rat brain tumor cells. J Cell Biochem 1995; 57:150-62. [PMID: 7721954 DOI: 10.1002/jcb.240570115] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Withangulatin A (WA), a newly discovered withanolide isolated from an antitumor Chinese herb, has been shown to be a vimentin intermediate filament-targeting drug by using immunofluorescence microscopy. Together with cytochalasin D and colchicine, these drugs were employed to investigate the importance of vimentin intermediate filaments, actin filaments, and microtubules in the development of acquired thermotolerance in 9L rat brain tumor cells treated at 45 degrees C for 15 min (priming heat-shock). Acquired thermotolerance was abrogated in cells incubated with WA before the priming heat-shock but it could be detected in cells treated with WA after the priming heat-shock. In contrast, cytochalasin D and colchicine do not interfere with the development of thermotolerance at all. The intracellular localizations of vimentin and the constitutive heat-shock protein70 (HSC70) in treated cells were examined by using immunofluorescence microscopy and detergent-extractability studies. In cells treated with WA before the priming heat-shock, vimentin IFs were tightly aggregated around the nucleus and unable to return to their normal organization after a recovery under normal growing conditions. In contrast, the IF network in cells treated with WA after the priming heat-shock was able to reorganize into filamentous form after a recovery period, a behavior similar to that of the cells treated with heat-shock only. HSC70 was found to be co-localized with vimentin during these changes. It is suggested that the integrity of intermediate filaments is important for the development of thermotolerance and that HSC70 may be involved in this process by stabilizing the intermediate filaments through direct or indirect binding.
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Affiliation(s)
- Y C Lee
- Institute of Life Science, National Tsing Hua University, Hsinchu, Taiwan, Republic of China
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