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Cheng CH, Tian Y, Ma HL, Liu GX, Fan SG, Deng YQ, Jiang JJ, Feng J, Guo ZX. Essential role of the HSC70 in the mud crab Scylla paramamosain in response to Vibrio parahaemolyticus infection. FISH & SHELLFISH IMMUNOLOGY 2023; 141:109078. [PMID: 37716494 DOI: 10.1016/j.fsi.2023.109078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 09/05/2023] [Accepted: 09/13/2023] [Indexed: 09/18/2023]
Abstract
Heat shock proteins play an important role in host defense, and modulate immune responses against pathogen infection. In this study, a novel HSC70 from the mud crab (designated as SpHSC70) was cloned and characterized. The full length of SpHSC70 contained a 58 bp 5'untranslated region (UTR), an open reading frame (ORF) of 2,046 bp and a 3'UTR of 341 bp. The SpHSC70 protein included the conserved DnaK motif. The mRNA of SpHSC70 was highly expressed in the hemocytes, heart and hepatopancreas, and lowly expressed in the intestine. The subcellular localization results indicated that SpHSC70 was localized in both the cytoplasm and the nucleus. Moreover, SpHSC70 was significantly responsive to bacterial challenge. RNA interference experiment was designed to investigate the roles of SpHSC70 in response to bacterial challenge. V. parahaemolyticus infection induced the expression levels of SpPO, SpHSP70, SpSOD and SpCAT. Knocking down SpHSC70 in vivo can decrease the expression of these genes after V. parahaemolyticus infection. These results suggested that SpHSC70 could play a vital role in defense against V. parahaemolyticus infection via activating the immune response and antioxidant defense signaling pathways in the mud crab.
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Affiliation(s)
- Chang-Hong Cheng
- Key Laboratory of South China Sea Fishery Resources Exploitation & Utilization, Ministry of Agriculture and Rural Affairs, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, Guangdong, 510300, PR China.
| | - Yu Tian
- Key Laboratory of South China Sea Fishery Resources Exploitation & Utilization, Ministry of Agriculture and Rural Affairs, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, Guangdong, 510300, PR China
| | - Hong-Ling Ma
- Key Laboratory of South China Sea Fishery Resources Exploitation & Utilization, Ministry of Agriculture and Rural Affairs, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, Guangdong, 510300, PR China
| | - Guang-Xin Liu
- Key Laboratory of South China Sea Fishery Resources Exploitation & Utilization, Ministry of Agriculture and Rural Affairs, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, Guangdong, 510300, PR China
| | - Si-Gang Fan
- Key Laboratory of South China Sea Fishery Resources Exploitation & Utilization, Ministry of Agriculture and Rural Affairs, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, Guangdong, 510300, PR China
| | - Yi-Qin Deng
- Key Laboratory of South China Sea Fishery Resources Exploitation & Utilization, Ministry of Agriculture and Rural Affairs, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, Guangdong, 510300, PR China
| | - Jian-Jun Jiang
- Key Laboratory of South China Sea Fishery Resources Exploitation & Utilization, Ministry of Agriculture and Rural Affairs, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, Guangdong, 510300, PR China
| | - Juan Feng
- Key Laboratory of South China Sea Fishery Resources Exploitation & Utilization, Ministry of Agriculture and Rural Affairs, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, Guangdong, 510300, PR China
| | - Zhi-Xun Guo
- Key Laboratory of South China Sea Fishery Resources Exploitation & Utilization, Ministry of Agriculture and Rural Affairs, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, Guangdong, 510300, PR China.
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2
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Pande S, Ghosh DK. Nuclear proteostasis imbalance in laminopathy-associated premature aging diseases. FASEB J 2023; 37:e23116. [PMID: 37498235 DOI: 10.1096/fj.202300878r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 06/15/2023] [Accepted: 07/13/2023] [Indexed: 07/28/2023]
Abstract
Laminopathies are a group of rare genetic disorders with heterogeneous clinical phenotypes such as premature aging, cardiomyopathy, lipodystrophy, muscular dystrophy, microcephaly, epilepsy, and so on. The cellular phenomena associated with laminopathy invariably show disruption of nucleoskeleton of lamina due to deregulated expression, localization, function, and interaction of mutant lamin proteins. Impaired spatial and temporal tethering of lamin proteins to the lamina or nucleoplasmic aggregation of lamins are the primary molecular events that can trigger nuclear proteotoxicity by modulating differential protein-protein interactions, sequestering quality control proteins, and initiating a cascade of abnormal post-translational modifications. Clearly, laminopathic cells exhibit moderate to high nuclear proteotoxicity, raising the question of whether an imbalance in nuclear proteostasis is involved in laminopathic diseases, particularly in diseases of early aging such as HGPS and laminopathy-associated premature aging. Here, we review nuclear proteostasis and its deregulation in the context of lamin proteins and laminopathies.
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Affiliation(s)
- Shruti Pande
- Department of Medical Genetics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India
| | - Debasish Kumar Ghosh
- Enteric Disease Division, Department of Microbiology, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India
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3
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Seese SE, Muheisen S, Gath N, Gross JM, Semina EV. Identification of HSPA8 as an interacting partner of MAB21L2 and an important factor in eye development. Dev Dyn 2023; 252:510-526. [PMID: 36576422 PMCID: PMC10947772 DOI: 10.1002/dvdy.560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2022] [Revised: 11/04/2022] [Accepted: 11/18/2022] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND Pathogenic variants in human MAB21L2 result in microphthalmia, anophthalmia, and coloboma. The exact molecular function of MAB21L2 is currently unknown. We conducted a series of yeast two-hybrid (Y2H) experiments to determine protein interactomes of normal human and zebrafish MAB21L2/mab21l2 as well as human disease-associated variant MAB21L2-p.(Arg51Gly) using human adult retina and zebrafish embryo libraries. RESULTS These screens identified klhl31, tnpo1, TNPO2/tnpo2, KLC2/klc2, and SPTBN1/sptbn1 as co-factors of MAB21L2/mab21l2. Several factors, including hspa8 and hspa5, were found to interact with MAB21L2-p.Arg51Gly but not wild-type MAB21L2/mab21l2 in Y2H screens. Further analyses via 1-by-1 Y2H assays, co-immunoprecipitation, and mass spectrometry revealed that both normal and variant MAB21L2 interact with HSPA5 and HSPA8. In situ hybridization detected co-expression of hspa5 and hspa8 with mab21l2 during eye development in zebrafish. Examination of zebrafish mutant hspa8hi138Tg identified reduced hspa8 expression associated with severe ocular developmental defects, including small eye, coloboma, and anterior segment dysgenesis. To investigate the effects of hspa8 deficiency on the mab21l2Arg51_Phe52del allele, corresponding zebrafish double mutants were generated and found to be more severely affected than single mutant lines. CONCLUSION This study identifies heat shock proteins as interacting partners of MAB21L2/mab21l2 and suggests a role for this interaction in vertebrate eye development.
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Affiliation(s)
- Sarah E. Seese
- Department of Pediatrics The Medical College of Wisconsin, Milwaukee, WI 53226, USA
- Cell Biology, Neurobiology and Anatomy, The Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Sanaa Muheisen
- Department of Pediatrics The Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Natalie Gath
- University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Jeffrey M. Gross
- University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Elena V. Semina
- Department of Pediatrics The Medical College of Wisconsin, Milwaukee, WI 53226, USA
- Cell Biology, Neurobiology and Anatomy, The Medical College of Wisconsin, Milwaukee, WI 53226, USA
- Department of Ophthalmology and Visual Sciences, Medical College of Wisconsin, Children’s of Wisconsin, Milwaukee, WI 53226, USA
- Children’s Research Institute, Medical College of Wisconsin, Children’s of Wisconsin, Milwaukee, WI 53226, USA
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4
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Tanida T, Matsuda KI, Tanaka M. Novel metabolic system for lactic acid via LRPGC1/ERRγ signaling pathway. FASEB J 2020; 34:13239-13256. [PMID: 32851675 DOI: 10.1096/fj.202000492r] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 06/25/2020] [Accepted: 07/10/2020] [Indexed: 12/17/2022]
Abstract
Lactic acid (LA) is a byproduct of glycolysis resulting from intense exercise or a metabolic defect in aerobic processes. LA metabolism is essential to prevent lactic acidosis, but the mechanism through which LA regulates its own metabolism is largely unknown. Here, we identified a LA-responsive protein, named LRPGC1, which has a distinct role from PGC1α, a key metabolic regulator, and report that LRPGC1 particularly mediates LA response to activate liver LA metabolism. Following LA stimulation, LRPGC1, but not PGC1α, translocates from the cytoplasm to the nucleus through deactivation of nuclear export signals, interacts with the nuclear receptor ERRγ, and upregulates TFAM, which ensures mitochondrial biogenesis. Knockout of PGC1 gene in HepG2 hepatocarcinoma cells decreased the LA consumption and TFAM expression, which were rescued by LRPGC1 expression, but not by PGC1α. These LRPGC1-induced effects were mediated by ERRγ, concomitantly with mitochondrial activation. The response element for LRPGC1/ERRγ signaling pathway was identified in TFAM promoter. Notably, the survival rate of a mouse model of lactic acidosis was reduced by the liver-targeted silencing of Lrpgc1, while it was significantly ameliorated by the pharmacological activation of ERRγ. These findings demonstrate LA-responsive transactivation via LRPGC1 that highlight an intrinsic molecular mechanism for LA homeostasis.
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Affiliation(s)
- Takashi Tanida
- Department of Anatomy and Neurobiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Ken Ichi Matsuda
- Department of Anatomy and Neurobiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Masaki Tanaka
- Department of Anatomy and Neurobiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
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5
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Dong XM, Zhao K, Zheng WW, Xu CW, Zhang MJ, Yin RH, Gao R, Tang LJ, Liu JF, Chen H, Zhan YQ, Yu M, Ge CH, Gao HY, Li X, Luo T, Ning HM, Yang XM, Li CY. EDAG mediates Hsp70 nuclear localization in erythroblasts and rescues dyserythropoiesis in myelodysplastic syndrome. FASEB J 2020; 34:8416-8427. [PMID: 32350948 DOI: 10.1096/fj.201902946r] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 04/06/2020] [Accepted: 04/13/2020] [Indexed: 12/11/2022]
Abstract
During human erythroid maturation, Hsp70 translocates into the nucleus and protects GATA-1 from caspase-3 cleavage. Failure of Hsp70 to localize to the nucleus was found in Myelodysplastic syndrome (MDS) erythroblasts and can induce dyserythropoiesis, with arrest of maturation and death of erythroblasts. However, the mechanism of the nuclear trafficking of Hsp70 in erythroblasts remains unknown. Here, we found the hematopoietic transcriptional regulator, EDAG, to be a novel binding partner of Hsp70 that forms a protein complex with Hsp70 and GATA-1 during human normal erythroid differentiation. EDAG overexpression blocked the cytoplasmic translocation of Hsp70 induced by EPO deprivation, inhibited GATA-1 degradation, thereby promoting erythroid maturation in an Hsp70-dependent manner. Furthermore, in myelodysplastic syndrome (MDS) patients with dyserythropoiesis, EDAG is dramatically down-regulated, and forced expression of EDAG has been found to restore the localization of Hsp70 in the nucleus and elevate the protein level of GATA-1 to a significant extent. In addition, EDAG rescued the dyserythropoiesis of MDS patients by increasing erythroid differentiation and decreasing cell apoptosis. This study demonstrates the molecular mechanism of Hsp70 nuclear sustaining during erythroid maturation and establishes that EDAG might be a suitable therapeutic target for dyserythropoiesis in MDS patients.
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Affiliation(s)
- Xiao-Ming Dong
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, Beijing Institute of Lifeomics, Beijing, China.,Department of Pharmaceutical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, China.,College of Life Sciences, Shaanxi Normal University, Xi'an, China
| | - Ke Zhao
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, Beijing Institute of Lifeomics, Beijing, China
| | - Wei-Wei Zheng
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, Beijing Institute of Lifeomics, Beijing, China
| | - Cheng-Wang Xu
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, Beijing Institute of Lifeomics, Beijing, China
| | - Mei-Jiang Zhang
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, Beijing Institute of Lifeomics, Beijing, China.,Department of Pharmaceutical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, China
| | - Rong-Hua Yin
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, Beijing Institute of Lifeomics, Beijing, China
| | - Rui Gao
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, Beijing Institute of Lifeomics, Beijing, China
| | - Liu-Jun Tang
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, Beijing Institute of Lifeomics, Beijing, China
| | - Jin-Fang Liu
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, Beijing Institute of Lifeomics, Beijing, China
| | - Hui Chen
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, Beijing Institute of Lifeomics, Beijing, China
| | - Yi-Qun Zhan
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, Beijing Institute of Lifeomics, Beijing, China
| | - Miao Yu
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, Beijing Institute of Lifeomics, Beijing, China
| | - Chang-Hui Ge
- Department of Experimental Hematology and Biochemistry, Beijing Institute of Radiation Medicine, Beijing, China
| | - Hui-Ying Gao
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, Beijing Institute of Lifeomics, Beijing, China
| | - Xiu Li
- School of Postgraduate, Anhui Medical University, Hefei, China
| | - Teng Luo
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, Beijing Institute of Lifeomics, Beijing, China
| | - Hong-Mei Ning
- Department of Hematopoietic Stem Cell Transplantation, The Fifth Medical Center of Chinese PLA General Hospital, Beijing, China
| | - Xiao-Ming Yang
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, Beijing Institute of Lifeomics, Beijing, China.,Department of Pharmaceutical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, China.,School of Postgraduate, Anhui Medical University, Hefei, China
| | - Chang-Yan Li
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, Beijing Institute of Lifeomics, Beijing, China.,School of Postgraduate, Anhui Medical University, Hefei, China
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6
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Cafe SL, Nixon B, Dun MD, Roman SD, Bernstein IR, Bromfield EG. Oxidative Stress Dysregulates Protein Homeostasis Within the Male Germ Line. Antioxid Redox Signal 2020; 32:487-503. [PMID: 31830800 DOI: 10.1089/ars.2019.7832] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Aims: Oxidative stress is causally linked to male reproductive pathologies, driven primarily by lipid peroxidation and an attendant production of highly reactive lipid aldehydes, such as 4-hydroxynonenal (4HNE) within the male germ line. In somatic cells, 4HNE dysregulates proteostasis via targeting of vulnerable proteins for adduction, causing protein misfolding and eventually aggregation. The aims of this study were to explore whether oxidative stress precipitates an equivalent response in the male germ line and determine the protective mechanisms used by germ cells to prevent this cascade of protein damage. Results: We reveal a causative role for oxidative stress in the accumulation of protein deposits in male germ cells. Specifically, 4HNE treatment resulted in a significant increase in cytosolic protein aggregation within pre- and post-meiotic germ cells as measured by the aggregate-detecting fluorophores ProteoStat and Thioflavin T, and the amyloid-specific anti-A11 and anti-OC antibodies. Our data implicate nucleocytoplasmic transport machinery and molecular chaperones as potential mechanisms for the subcellular compartmentalization and/or suppression of aggregating proteins. Thus, the inhibition of karyopherin transport proteins and molecular chaperones resulted in a significant increase in the accumulation of aggregated cellular protein. Innovation: These data establish the novel paradigm that lipid peroxidation is a key contributor to a decline in proteostasis in developing germ cells. These findings will inform the development of novel strategies to protect germ cells from oxidative stress. Conclusion: Together, these results shed light on proteostasis mechanisms that may assist in the management of misfolded proteins in the male germ line under conditions of acute oxidative stress.
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Affiliation(s)
- Shenae Louise Cafe
- Priority Research Centre for Reproductive Science, School of Environmental and Life Sciences, Discipline of Biological Sciences, University of Newcastle, Callaghan, Australia
| | - Brett Nixon
- Priority Research Centre for Reproductive Science, School of Environmental and Life Sciences, Discipline of Biological Sciences, University of Newcastle, Callaghan, Australia
| | - Matthew D Dun
- Cancer Signaling Research Group, School of Biomedical Sciences, Faculty of Health and Medicine, University of Newcastle, Callaghan, Australia.,Priority Research Centre for Cancer Research Innovation and Translation, Hunter Medical Research Institute, Lambton, Australia
| | - Shaun Daryl Roman
- Priority Research Centre for Reproductive Science, School of Environmental and Life Sciences, Discipline of Biological Sciences, University of Newcastle, Callaghan, Australia.,Priority Research Centre for Drug Development, School of Environmental and Life Sciences, Discipline of Biological Sciences, University of Newcastle, Callaghan, Australia
| | - Ilana Ruth Bernstein
- Priority Research Centre for Reproductive Science, School of Environmental and Life Sciences, Discipline of Biological Sciences, University of Newcastle, Callaghan, Australia
| | - Elizabeth Grace Bromfield
- Priority Research Centre for Reproductive Science, School of Environmental and Life Sciences, Discipline of Biological Sciences, University of Newcastle, Callaghan, Australia.,Department of Biochemistry and Cell Biology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
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7
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Blocking nuclear export of HSPA8 after heat shock stress severely alters cell survival. Sci Rep 2018; 8:16820. [PMID: 30429537 PMCID: PMC6235846 DOI: 10.1038/s41598-018-34887-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Accepted: 10/23/2018] [Indexed: 12/12/2022] Open
Abstract
The nuclear translocation of endogenous heat shock cognate protein HSPA8 is a requisite for cell survival during oxidative and heat shock stress. Upon these events, cytoplasmic HSPA8 is thought to concentrate within the nucleus and nucleolus. When the situation returns to normal, HSPA8 is released from its nuclear/nucleolar anchors and redistributes into the cytoplasm. By using different stress conditions and a 21-mer phosphopeptide tool called P140, which binds HSPA8 and hampers its chaperone properties, we deciphered the cellular and molecular effects arising during this vital cytoplasmic-nuclear-cytoplasmic shuttling process. Using the non-metastatic fibroblastoid cell line MRL/N-1 derived from a MRL/MpTn-gld/gld lupus-prone mouse, we discovered that P140 treatment neutralized the egress of HSPA8 from nucleus to cytoplasm in the cell recovery phase. This lack of relocation of HSPA8 into the cytoplasm of heat-shocked MRL/N-1 cells altered the ability of these cells to survive when a second mild oxidative stress mimicking inflammatory conditions was applied. Crosslinking experiments followed by proteomics studies showed that P140 binds regions close to nuclear import and export signal sequences encompassed within the HSPA8 structure. These data are consistent with HSPA8 having a crucial cell protective role against reactive oxygen species (ROS) production by mitochondria during inflammatory conditions.
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8
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Nitric oxide mediated redox regulation of protein homeostasis. Cell Signal 2018; 53:348-356. [PMID: 30408515 DOI: 10.1016/j.cellsig.2018.10.019] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 10/27/2018] [Accepted: 10/29/2018] [Indexed: 12/12/2022]
Abstract
Nitric oxide is a versatile diffusible signaling molecule, whose biosynthesis by three NO synthases (NOS) is tightly regulated at transcriptional and posttranslational levels, availability of co-factors, and calcium binding. Above normal levels of NO have beneficial protective effects for example in the cardiovascular system, but also contribute to the pathophysiology in the context of inflammatory diseases, and to aging and neurodegeneration in the nervous system. The effect specificity relies on the functional and spatial specificity of the NOS isoenzymes, and on the duality of two major signaling mechanisms (i) activation of soluble guanylycylase (sGC)-dependent cGMP production and (ii) direct S-nitrosylation of redox sensitive cysteines of susceptible proteins. The present review summarizes the functional implications of S-nitrosylation in the context of proteostasis, and focuses on two NO target proteins, heat shock cognate of 70 kDa (Hsc70/HSPA8) and the ubiquitin 2 ligase (UBE2D), because both are modified on functionally critical cysteines and are key regulators of chaperone mediated and assisted autophagy and proteasomal protein degradation. SNO modifications of these candidates are associated with protein accumulations and adoption of a senescent phenotype of neuronal cells suggesting that S-nitrosylations of protein homeostatic machineries contribute to aging phenomena.
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9
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Nitric oxide contributes to protein homeostasis by S-nitrosylations of the chaperone HSPA8 and the ubiquitin ligase UBE2D. Redox Biol 2018; 20:217-235. [PMID: 30368041 PMCID: PMC6202877 DOI: 10.1016/j.redox.2018.10.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2018] [Revised: 09/25/2018] [Accepted: 10/02/2018] [Indexed: 02/06/2023] Open
Abstract
Upregulations of neuronal nitric oxide synthase (nNOS) in the rodent brain have been associated with neuronal aging. To address underlying mechanisms we generated SH-SY5Y neuronal cells constitutively expressing nNOS at a level similar to mouse brain (nNOS+ versus MOCK). Initial experiments revealed S-nitrosylations (SNO) of key players of protein homeostasis: heat shock cognate HSC70/HSPA8 within its nucleotide-binding site, and UBE2D ubiquitin conjugating enzymes at the catalytic site cysteine. HSPA8 is involved in protein folding, organelle import/export and chaperone-mediated LAMP2a-dependent autophagy (CMA). A set of deep redox and full proteome analyses, plus analysis of autophagy, CMA and ubiquitination with rapamycin and starvation as stimuli confirmed the initial observations and revealed a substantial increase of SNO modifications in nNOS+ cells, in particular targeting protein networks involved in protein catabolism, ubiquitination, carbohydrate metabolism and cell cycle control. Importantly, NO-independent reversible oxidations similarly occurred in both cell lines. Functionally, nNOS caused an accumulation of proteins, including CMA substrates and loss of LAMP2a. UBE2D activity and proteasome activity were impaired, resulting in dysregulations of cell cycle checkpoint proteins. The observed changes of protein degradation pathways caused an expansion of the cytoplasm, large lysosomes, slowing of the cell cycle and suppression of proliferation suggesting a switch of the phenotype towards aging, supported by downregulations of neuronal progenitor markers but increase of senescence-associated proteins. Hence, upregulation of nNOS in neuronal cells imposes aging by SNOing of key players of ubiquitination, chaperones and of substrate proteins leading to interference with crucial steps of protein homeostasis.
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10
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Fung HYJ, Fu SC, Chook YM. Nuclear export receptor CRM1 recognizes diverse conformations in nuclear export signals. eLife 2017; 6:e23961. [PMID: 28282025 PMCID: PMC5358978 DOI: 10.7554/elife.23961] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Accepted: 03/09/2017] [Indexed: 12/14/2022] Open
Abstract
Nuclear export receptor CRM1 binds highly variable nuclear export signals (NESs) in hundreds of different cargoes. Previously we have shown that CRM1 binds NESs in both polypeptide orientations (Fung et al., 2015). Here, we show crystal structures of CRM1 bound to eight additional NESs which reveal diverse conformations that range from loop-like to all-helix, which occupy different extents of the invariant NES-binding groove. Analysis of all NES structures show 5-6 distinct backbone conformations where the only conserved secondary structural element is one turn of helix that binds the central portion of the CRM1 groove. All NESs also participate in main chain hydrogen bonding with human CRM1 Lys568 side chain, which acts as a specificity filter that prevents binding of non-NES peptides. The large conformational range of NES backbones explains the lack of a fixed pattern for its 3-5 hydrophobic anchor residues, which in turn explains the large array of peptide sequences that can function as NESs.
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MESH Headings
- Active Transport, Cell Nucleus
- Amino Acid Sequence
- Binding Sites
- Cell Nucleus/metabolism
- Cloning, Molecular
- Crystallography, X-Ray
- Gene Expression
- Humans
- Hydrogen Bonding
- Hydrophobic and Hydrophilic Interactions
- Karyopherins/chemistry
- Karyopherins/genetics
- Karyopherins/metabolism
- Models, Molecular
- Nuclear Export Signals
- Protein Binding
- Protein Conformation, alpha-Helical
- Protein Conformation, beta-Strand
- Protein Interaction Domains and Motifs
- Receptors, Cytoplasmic and Nuclear/chemistry
- Receptors, Cytoplasmic and Nuclear/genetics
- Receptors, Cytoplasmic and Nuclear/metabolism
- Recombinant Proteins/chemistry
- Recombinant Proteins/genetics
- Recombinant Proteins/metabolism
- Sequence Alignment
- Sequence Homology, Amino Acid
- Thermodynamics
- Exportin 1 Protein
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Affiliation(s)
- Ho Yee Joyce Fung
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, United States
| | - Szu-Chin Fu
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, United States
| | - Yuh Min Chook
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, United States
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11
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Zhang W, Cai C, Lin L, Tao YJ, Jin M. Subcellular localization and interactions of Infectious Salmon Anemia Virus (ISAV) M1 and NEP as well as host Hsc70. Virol J 2017; 14:30. [PMID: 28202040 PMCID: PMC5310077 DOI: 10.1186/s12985-017-0702-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 02/08/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Infectious salmon anemia virus (ISAV) is an important fish pathogen that causes high mortality in farmed Atlantic salmon. The ISAV genome consists of eight single-stranded, negative-sense RNA segments. The six largest segments contain one open reading frame (ORF) each, and encode three polymerase proteins, nucleoprotein, fusion protein, and hemagglutinin esterase protein. The two smallest segments contain more than one ORF each. The segment 7 encodes non-structural protein 1 (NS1) and nuclear export protein (NEP), while segment 8 encodes matrix protein 1 and 2 (M1 and M2). NS1 and M2 have been well known as antagonist of type I interferon. However, little is known about the characterization of M1 or NEP. In addition, heat shock cognate 70 (Hsc70) has been reported to interact with M1 and NEP of influenza viruses for the export of viral ribonucleoprotein (vRNP) via vRNP-M1-NEP complex, the goal of this study therefore was to characterize the subcellular localization and interactions of ISAV M1 and NEP as well as cellular Hsc70. RESULTS When M1, NEP, and Hsc70 were individually expressed in the stripped snakehead (SSN-1) cells, we found that M1 protein was localized in both cytosol and nucleus of the cells, NEP was localized only in the cytosol and accumulated adjacent to the nucleus, while Hsc70 was localized throughout the cytosol, but not in the nucleus. However, when two of them were co-expressed, we found that both M1 and Hsc70 were co-localized with NEP in the cytosol and accumulated adjacent to the nucleus, while M1 and Hsc70 were still localized as they were expressed individually. Furthermore, pull-down assay was performed and showed that NEP could interact with both M1 and Hsc70, and M1-Hsc70 interaction was also observed although the interaction was weaker than that of NEP-Hsc70. CONCLUSION Our study characterized the subcellular localization and interactions of three proteins including M1 and NEP of ISAV, and Hsc70. These data will help towards a better understanding of the life cycle of ISAV, especially the process of vRNP export.
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Affiliation(s)
- Wenting Zhang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, People's Republic of China
| | - Chengzhi Cai
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, People's Republic of China
| | - Li Lin
- Department of Aquatic Animal Medicine, College of Fisheries, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Yizhi Jane Tao
- Department of Biosciences, Rice University, Houston, TX, USA
| | - Meilin Jin
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, People's Republic of China.
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Pohl MO, Lanz C, Stertz S. Late stages of the influenza A virus replication cycle-a tight interplay between virus and host. J Gen Virol 2016; 97:2058-2072. [PMID: 27449792 DOI: 10.1099/jgv.0.000562] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
After successful infection and replication of its genome in the nucleus of the host cell, influenza A virus faces several challenges before newly assembled viral particles can bud off from the plasma membrane, giving rise to a new infectious virus. The viral ribonucleoprotein (vRNP) complexes need to exit from the nucleus and be transported to the virus assembly sites at the plasma membrane. Moreover, they need to be bundled to ensure the incorporation of precisely one of each of the eight viral genome segments into newly formed viral particles. Similarly, viral envelope glycoproteins and other viral structural proteins need to be targeted to virus assembly sites for viral particles to form and bud off from the plasma membrane. During all these steps influenza A virus heavily relies on a tight interplay with its host, exploiting host-cell proteins for its own purposes. In this review, we summarize current knowledge on late stages of the influenza virus replication cycle, focusing on the role of host-cell proteins involved in this process.
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Affiliation(s)
- Marie O Pohl
- Institute of Medical Virology, University of Zurich, 8057 Zurich, Switzerland
| | - Caroline Lanz
- Institute of Medical Virology, University of Zurich, 8057 Zurich, Switzerland
| | - Silke Stertz
- Institute of Medical Virology, University of Zurich, 8057 Zurich, Switzerland
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13
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Nucleocytoplasmic transport under stress conditions and its role in HSP70 chaperone systems. Biochim Biophys Acta Gen Subj 2014; 1840:2953-60. [DOI: 10.1016/j.bbagen.2014.04.022] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Revised: 04/11/2014] [Accepted: 04/28/2014] [Indexed: 11/20/2022]
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14
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Watanabe K, Shimizu T, Noda S, Tsukahara F, Maru Y, Kobayashi N. Nuclear export of the influenza virus ribonucleoprotein complex: Interaction of Hsc70 with viral proteins M1 and NS2. FEBS Open Bio 2014; 4:683-8. [PMID: 25161876 PMCID: PMC4141210 DOI: 10.1016/j.fob.2014.07.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Revised: 07/04/2014] [Accepted: 07/04/2014] [Indexed: 11/26/2022] Open
Abstract
The influenza virus replicates in the host cell nucleus, and the progeny viral ribonucleoprotein complex (vRNP) is exported to the cytoplasm prior to maturation. NS2 has a nuclear export signal that mediates the nuclear export of vRNP by the vRNP-M1-NS2 complex. We previously reported that the heat shock cognate 70 (Hsc70) protein binds to M1 protein and mediates vRNP export. However, the interactions among M1, NS2, and Hsc70 are poorly understood. In the present study, we demonstrate that Hsc70 interacts with M1 more strongly than with NS2 and competes with NS2 for M1 binding, suggesting an important role of Hsc70 in the nuclear export of vRNP.
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Affiliation(s)
- Ken Watanabe
- Laboratory of Molecular Biology of Infectious Agents, Graduate School of Biomedical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan
| | - Teppei Shimizu
- Laboratory of Molecular Biology of Infectious Agents, Graduate School of Biomedical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan
| | - Saiko Noda
- Laboratory of Molecular Biology of Infectious Agents, Graduate School of Biomedical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan
| | - Fujiko Tsukahara
- Department of Pharmacology, Tokyo Women's Medical University, School of Medicine, 8-1, Kawada-cho, Shinjuku-ku, Tokyo 162-8666, Japan
| | - Yoshiro Maru
- Department of Pharmacology, Tokyo Women's Medical University, School of Medicine, 8-1, Kawada-cho, Shinjuku-ku, Tokyo 162-8666, Japan
| | - Nobuyuki Kobayashi
- Laboratory of Molecular Biology of Infectious Agents, Graduate School of Biomedical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan ; Central Research Center, AVSS Corporation, 1-22, Wakaba-machi, Nagasaki 852-8137, Japan
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15
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Connexin43 functions as a novel interacting partner of heat shock cognate protein 70. Sci Rep 2014; 3:2719. [PMID: 24056538 PMCID: PMC3779846 DOI: 10.1038/srep02719] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Accepted: 09/04/2013] [Indexed: 01/12/2023] Open
Abstract
Regulation of connexin43 (Cx43) expression affects cell proliferation, differentiation and apoptosis in a gap junctional intercellular communication (GJIC)-independent manner. However, the underlying mechanisms of Cx43-mediated cell cycle suppression are still poorly understood. To elucidate the molecular mechanism of Cx43-mediated cell cycle suppression, we searched for Cx43 interacting proteins by using a proteomics approach. Here, we have identified a Cx43-interacting protein, heat shock cognate protein 70 (Hsc70). We confirmed that Hsc70 directly binds to the C-terminus of Cx43, whereas Hsc54, a splice variant of Hsc70, does not, that Cx43 competes with cyclin D1 for binding to Hsc70, and that the nuclear accumulation of cyclin D1 is reduced by overexpression of Cx43 in a GJIC-independent manner, which is restored by co-overexpression with Hsc70. As a result, the cell proliferation is regulated by Cx43. Our results suggest that Cx43-Hsc70 interaction probably plays a critical role during G1/S progression.
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16
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Imamura Y, Wang PL. Salivary histatin 3 inhibits heat shock cognate protein 70-mediated inflammatory cytokine production through toll-like receptors in human gingival fibroblasts. JOURNAL OF INFLAMMATION-LONDON 2014; 11:4. [PMID: 24495360 PMCID: PMC3922778 DOI: 10.1186/1476-9255-11-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/01/2012] [Accepted: 01/30/2014] [Indexed: 11/29/2022]
Abstract
Background Salivary histatins are bioactive peptides related to the innate immune system associated with antimicrobial activities. However, very little is known about the physiological and biological functions of histatins against host cells or their role in oral cell inflammation. Histatin 3 binds to heat shock cognate protein 70 (HSC70, a constitutively expressed heat shock protein (HSP)). It is unclear whether HSC70 is involved in the inflammatory response in oral cells. Injured oral cells release some intracellular proteins including HSC70. It is possible that released HSC70 induces toll-like receptor (TLR) activation, just as extracellular HSP70 (a stress inducible HSP) does, and that histatin 3 affects this process. Therefore, we tested the hypothesis that HSC70 activates TLR signaling and histatin 3 inhibits this activation and inflammatory cytokine production. Methods A nuclear factor (NF)-κB-dependent luciferase reporter plasmid was transfected into HEK293 cells stably expressing TLR2 with coreceptor CD14 (293-TLR2/CD14 cells) or stably expressing TLR4 with CD14 and the accessory molecule MD2 (293-TLR4/MD2-CD14 cells). The cells were stimulated with HSC70 in the presence or absence of histatin 3, and examined using luciferase assays. We also stimulated human gingival fibroblasts (HGFs) with HSC70 with or without histatin 3. Then, we analyzed the levels of inflammatory cytokines (interleukin (IL)-6 and IL-8) in the culture media. Cell proteins were analyzed using enzyme-linked immunosorbent assay and Western blotting with antibodies of mitogen-activated protein kinases and NF-κB inhibitor IκB-α, respectively. Histatin 3-bound form of HSC70 was analyzed using limited V8 protease proteolysis. Results HSC70 induced NF-κB activation in a dose-dependent manner in 293-TLR2/CD14 and 293-TLR4/MD2-CD14 cells, and histatin 3 inhibited this process and when histatin 3 binding to HSC70 was precluded by 15-deoxyspergualin, which augmented NF-κB-triggered activation. In HGFs, histatin 3 also inhibited HSC70-induced inflammatory cytokine production, extracellular signal-regulated protein kinase phosphorylation, and degradation of IκB-α. Moreover, HSC70 in the presence of histatin 3 was relatively resistant to digestion by V8 protease compared with HSC70 in the presence of control peptide. Conclusions Histatin 3 may be an inhibitor of HSC70-triggered activation of TLR signaling and inflammatory cytokine production and may be involved in inflammation processes noted in oral cells.
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Affiliation(s)
- Yasuhiro Imamura
- Department of Pharmacology, Matsumoto Dental University, Shiojiri, Nagano, Japan.
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17
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Stricher F, Macri C, Ruff M, Muller S. HSPA8/HSC70 chaperone protein: structure, function, and chemical targeting. Autophagy 2013; 9:1937-54. [PMID: 24121476 DOI: 10.4161/auto.26448] [Citation(s) in RCA: 259] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
HSPA8/HSC70 protein is a fascinating chaperone protein. It represents a constitutively expressed, cognate protein of the HSP70 family, which is central in many cellular processes. In particular, its regulatory role in autophagy is decisive. We focused this review on HSC70 structure-function considerations and based on this, we put a particular emphasis on HSC70 targeting by small molecules and peptides in order to develop intervention strategies that deviate some of HSC70 properties for therapeutic purposes. Generating active biomolecules regulating autophagy via its effect on HSC70 can effectively be designed only if we understand the fine relationships between HSC70 structure and functions.
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Affiliation(s)
- François Stricher
- CNRS; Institut de Biologie Moléculaire et Cellulaire; Immunopathologie et Chimie Thérapeutique/Laboratory of Excellence Medalis; Strasbourg, France
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18
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Watanabe K, Takatsuki H, Sonoda M, Tamura S, Murakami N, Kobayashi N. Anti-influenza viral effects of novel nuclear export inhibitors from Valerianae Radix and Alpinia galanga. Drug Discov Ther 2012; 5:26-31. [PMID: 22466093 DOI: 10.5582/ddt.v5.1.26] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Many pathogenic viruses, such as the influenza virus and the Human Immunodeficiency Virus (HIV)-1, are a threat to humans, thus leading to thousands of deaths annually. The development of antiviral drugs is urgent, and it is an essential strategy for the suppression of these infectious diseases. However, regardless of the rapid emergence of many infectious diseases, the development of novel antiviral drugs has been slow, except for the case of the AIDS. In addition, several viruses can easily mutate and escape the inhibitory activity of anti-viral drugs. It was already well-established that HIV escapes from anti-viral drug effects because of the lack of proofreading activity in its reverse transcriptase. It is known that the influenza virus, which is resistant to Tamiflu, is already spread all over the world. Viruses utilize the host cell environment and cellular factors to propagate. Therefore, the development of novel drugs which inhibit viral protein-host protein interactions or cellular functions appear to be good candidates. The influenza virus is unique in replicating in host nuclei, and we therefore focused on the nuclear export processes for the development of anti-influenza viral drugs. We previously reported that leptomycin B (LMB), which inhibited the nuclear export processes via the nuclear export signal (NES) inhibited the nuclear export of influenza viral RNP (vRNP), and resulted in the inhibition of influenza viral propagation. We herein examined novel CRM1 inhibitors, valtrate from Valerianae Radix, and 1'-acetoxychavicol acetate (ACA) from Alpinia galanga as potent inhibitors for the influenza virus replication.
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Affiliation(s)
- K Watanabe
- Laboratory of Molecular Biology of Infectious Agents, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
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19
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Abkallo HM, Kawano H, Watanabe K, Kobayashi N. A new cell-based reporter system for sensitive screening of nuclear export inhibitors. Drug Discov Ther 2012; 5:286-92. [PMID: 22466439 DOI: 10.5582/ddt.2011.v5.6.286] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Nucleocytoplasmic transport of proteins across the nuclear pore complex (NPC), mediated by the nuclear localization signal (NLS) and the nuclear export signal (NES), is a vital homeostatic process in eukaryotic cells and also in mitogen-activated protein kinase (MEK) signaling molecule in tumor cell proliferation. Some viruses, including the influenza virus and HIV-1, also employ this nuclear export mechanism during their life cycle. Hence, drugs that control nucleocytoplasmic transport of proteins are putative candidate antivirals or anti-cancer agents. Thus, we previously developed a GFP/NES-MDCK reporter cell system for screening novel nuclear export inhibitors. NES signal-conjugated GFP accumulates in the nucleus in the presence of the nuclear export inhibitor leptomycin B (LMB). In this study, a stable GFP/NLS/NES fusion protein-expressing cell line was established, and its potential as a reporter was evaluated. The GFP/NLS/NES-MDCK cell line demonstrates improved nuclear accumulation of GFP in a time-course treatment with LMB. In addition, the dose-response data demonstrated superior sensitivity of GFP/NLS/NES-MDCK over GFP/NES-MDCK cells. As low as 0.01 ng/mL LMB is sufficient to cause accumulation of the GFP fusion protein in the nucleus in GFP/NLS/NES-MDCK cells, while at least 1 ng/mL of LMB is needed for the accumulation of GFP fusion protein in the nucleus of GFP/NES-MDCK cells. These results indicate that the newly established GFP/NLS/NES-MDCK cell line is a potentially powerful tool to screen for novel nuclear export inhibitors.
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Affiliation(s)
- H M Abkallo
- Laboratory of Molecular Biology of Infectious Agents, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
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20
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Comprehensive review on the HSC70 functions, interactions with related molecules and involvement in clinical diseases and therapeutic potential. Pharmacol Ther 2012; 136:354-74. [PMID: 22960394 DOI: 10.1016/j.pharmthera.2012.08.014] [Citation(s) in RCA: 195] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2012] [Accepted: 08/14/2012] [Indexed: 12/28/2022]
Abstract
Heat shock cognate protein 70 (HSC70) is a constitutively expressed molecular chaperone which belongs to the heat shock protein 70 (HSP70) family. HSC70 shares some of the structural and functional similarity with HSP70. HSC70 also has different properties compared with HSP70 and other heat shock family members. HSC70 performs its full functions by the cooperation of co-chaperones. It interacts with many other molecules as well and regulates various cellular functions. It is also involved in various diseases and may become a biomarker for diagnosis and potential therapeutic targets for design, discovery, and development of novel drugs to treat various diseases. In this article, we provide a comprehensive review on HSC70 from the literatures including the basic general information such as classification, structure and cellular location, genetics and function, as well as its protein association and interaction with other proteins. In addition, we also discussed the relationship of HSC70 and related clinical diseases such as cancer, cardiovascular, neurological, hepatic and many other diseases and possible therapeutic potential and highlight the progress and prospects of research in this field. Understanding the functions of HSC70 and its interaction with other molecules will help us to reveal other novel properties of this protein. Scientists may be able to utilize this protein as a biomarker and therapeutic target to make significant advancement in scientific research and clinical setting in the future.
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21
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Gong X, Luo T, Deng P, Liu Z, Xiu J, Shi H, Jiang Y. Stress-induced interaction between p38 MAPK and HSP70. Biochem Biophys Res Commun 2012; 425:357-62. [DOI: 10.1016/j.bbrc.2012.07.096] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Accepted: 07/18/2012] [Indexed: 10/28/2022]
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22
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Mjahed H, Girodon F, Fontenay M, Garrido C. Heat shock proteins in hematopoietic malignancies. Exp Cell Res 2012; 318:1946-58. [PMID: 22652452 DOI: 10.1016/j.yexcr.2012.05.012] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2012] [Revised: 05/09/2012] [Accepted: 05/14/2012] [Indexed: 01/13/2023]
Abstract
Inducible heat shock proteins are molecular chaperones whose expression is increased after many different types of stress. They have a protective function helping the cell to cope with lethal conditions. Their basal expression is low in nonstressed, normal and nontransformed cells. However, in cancer cells and particularly in hematological malignancies, they are surprisingly abundant. Malignant cells have to rewire their metabolic requirements and therefore have a higher need for chaperones. This cancer cell addiction for HSPs is the basis for the use of HSP inhibitors in cancer therapy. HSPs have been shown to interact with different key apoptotic proteins. As a result, HSPs can essentially block the apoptotic pathways at several steps, most of them involving the activation of cystein proteases called caspases. Apoptosis and differentiation are physiological processes that share many common features, for instance, a controlled caspase activation and chromatin condensation are frequently observed. It is, therefore, not surprising that HSPs may be implicated in the differentiation process. HSPs may determine the fate of the cells by orchestrating the decision of apoptosis versus differentiation. This review will focus on the role of HSPs in hematological malignancies and the emerging therapeutic options that are being either proposed or used to target these protective proteins.
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Affiliation(s)
- Hajare Mjahed
- Inserm, UMR866, Faculty of Medicine, 7 Boulevard Jeanne D'Arc, F-21000 Dijon, France
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23
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Zou P, Yoshihara H, Hosokawa K, Tai I, Shinmyozu K, Tsukahara F, Maru Y, Nakayama K, Nakayama KI, Suda T. p57(Kip2) and p27(Kip1) cooperate to maintain hematopoietic stem cell quiescence through interactions with Hsc70. Cell Stem Cell 2011; 9:247-61. [PMID: 21885020 DOI: 10.1016/j.stem.2011.07.003] [Citation(s) in RCA: 188] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2010] [Revised: 02/15/2011] [Accepted: 07/07/2011] [Indexed: 01/03/2023]
Abstract
Cell cycle regulators play critical roles in the balance between hematopoietic stem cell (HSC) dormancy and proliferation. In this study, we report that cell cycle entry proceeded normally in HSCs null for cyclin-dependent kinase (CDK) inhibitor p57 due to compensatory upregulation of p27. HSCs null for both p57 and p27, however, were more proliferative and had reduced capacity to engraft in transplantation. We found that heat shock cognate protein 70 (Hsc70) interacts with both p57 and p27 and that the subcellular localization of Hsc70 was critical to maintain HSC cell cycle kinetics. Combined deficiency of p57 and p27 in HSCs resulted in nuclear import of an Hsc70/cyclin D1 complex, concomitant with Rb phosphorylation, and elicited severe defects in maintaining HSC quiescence. Taken together, these data suggest that regulation of cytoplasmic localization of Hsc70/cyclin D1 complex by p57 and p27 is a key intracellular mechanism in controlling HSC dormancy.
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Affiliation(s)
- Peng Zou
- Department of Cell Differentiation, The Sakaguchi Laboratory of Developmental Biology, Keio University School of Medicine, Shinjuku-ku, Tokyo 160-8582, Japan.
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Defective nuclear localization of Hsp70 is associated with dyserythropoiesis and GATA-1 cleavage in myelodysplastic syndromes. Blood 2011; 119:1532-42. [PMID: 22160620 DOI: 10.1182/blood-2011-03-343475] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Normal human erythroid cell maturation requests the transcription factor GATA-1 and a transient activation of caspase-3, with GATA-1 being protected from caspase-3-mediated cleavage by interaction with the chaperone heat shock protein 70 (Hsp70) in the nucleus. Erythroid cell dysplasia observed in early myelodysplastic syndromes (MDS) involves impairment of differentiation and excess of apoptosis with a burst of caspase activation. Analysis of gene expression in MDS erythroblasts obtained by ex vivo cultures demonstrates the down-regulation of a set of GATA-1 transcriptional target genes, including GYPA that encodes glycophorin A (GPA), and the up-regulation of members of the HSP70 family. GATA-1 protein expression is decreased in MDS erythroblasts, but restores in the presence of a pan-caspase inhibitor. Expression of a mutated GATA-1 that cannot be cleaved by caspase-3 rescues the transcription of GATA-1 targets, and the erythroid differentiation, but does not improve survival. Hsp70 fails to protect GATA-1 from caspases because the protein does not accumulate in the nucleus with active caspase-3. Expression of a nucleus-targeted mutant of Hsp70 protects GATA-1 and rescues MDS erythroid cell differentiation. Alteration of Hsp70 cytosolic-nuclear shuttling is a major feature of MDS that favors GATA-1 cleavage and differentiation impairment, but not apoptosis, in dysplastic erythroblasts.
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Scott MS, Boisvert FM, Lamond AI, Barton GJ. PNAC: a protein nucleolar association classifier. BMC Genomics 2011; 12:74. [PMID: 21272300 PMCID: PMC3038921 DOI: 10.1186/1471-2164-12-74] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2010] [Accepted: 01/27/2011] [Indexed: 01/11/2023] Open
Abstract
Background Although primarily known as the site of ribosome subunit production, the nucleolus is involved in numerous and diverse cellular processes. Recent large-scale proteomics projects have identified thousands of human proteins that associate with the nucleolus. However, in most cases, we know neither the fraction of each protein pool that is nucleolus-associated nor whether their association is permanent or conditional. Results To describe the dynamic localisation of proteins in the nucleolus, we investigated the extent of nucleolar association of proteins by first collating an extensively curated literature-derived dataset. This dataset then served to train a probabilistic predictor which integrates gene and protein characteristics. Unlike most previous experimental and computational studies of the nucleolar proteome that produce large static lists of nucleolar proteins regardless of their extent of nucleolar association, our predictor models the fluidity of the nucleolus by considering different classes of nucleolar-associated proteins. The new method predicts all human proteins as either nucleolar-enriched, nucleolar-nucleoplasmic, nucleolar-cytoplasmic or non-nucleolar. Leave-one-out cross validation tests reveal sensitivity values for these four classes ranging from 0.72 to 0.90 and positive predictive values ranging from 0.63 to 0.94. The overall accuracy of the classifier was measured to be 0.85 on an independent literature-based test set and 0.74 using a large independent quantitative proteomics dataset. While the three nucleolar-association groups display vastly different Gene Ontology biological process signatures and evolutionary characteristics, they collectively represent the most well characterised nucleolar functions. Conclusions Our proteome-wide classification of nucleolar association provides a novel representation of the dynamic content of the nucleolus. This model of nucleolar localisation thus increases the coverage while providing accurate and specific annotations of the nucleolar proteome. It will be instrumental in better understanding the central role of the nucleolus in the cell and its interaction with other subcellular compartments.
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Affiliation(s)
- Michelle S Scott
- Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK.
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26
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Abstract
Mammalian ribosome-associated complex (mRAC), consisting of the J-domain protein MPP11 and the atypical Hsp70 homolog (70-homolog) Hsp70L1, can partly complement the function of RAC, which is the homologous complex from Saccharomyces cerevisiae. RAC is the J-domain partner exclusively of the 70-homolog Ssb, which directly and independently of RAC binds to the ribosome. We here show that growth defects due to mRAC depletion in HeLa cells resemble those of yeast strains lacking RAC. Functional conservation, however, did not extend to the 70-homolog partner of mRAC. None of the major human 70-homologs was able to complement the growth defects of yeast strains lacking Ssb or was bound to ribosomes in an Ssb-like manner. Instead, our data suggest that mRAC was a specific partner of human Hsp70 but not of its close homolog Hsc70. On a mechanistic level, ATP binding, but not ATP hydrolysis, by Hsp70L1 affected mRAC's function as a J-domain partner of Hsp70. The combined data indicate that, while functionally conserved, yeast and mammalian cells have evolved distinct solutions to ensure that Hsp70-type chaperones can efficiently assist the biogenesis of newly synthesized polypeptide chains.
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Abstract
Abstract
Degradation of BCR-ABL oncoproteins by heat shock protein 90 (Hsp90) inhibitors in chronic myelogenous leukemia is expected to overcome resistance to ABL tyrosine kinase inhibitors. However, the precise mechanisms still remain to be uncovered. We found that while c-Cbl E3 ligase induced ubiquitin-dependent degradation of mature and phosphorylated BCR-ABL proteins, another E3 ligase CHIP (carboxyl terminus of the Hsc70-interacting protein) degraded immature BCR-ABL proteins and efficiently suppressed BCR-ABL–dependent leukemic growth. Interestingly, Bag1 (Bcl-2-associated athanogene-1), a nucleotide exchange factor for Hsc70, directly bound BCR-ABL with a high affinity, which was enhanced by CHIP and Hsp90 inhibitors, inhibited by imatinib and competed with Hsc70. Bag1 knockdown abrogated Hsp90 inhibitor-induced BCR-ABL degradation. Bag1 induced binding of immature BCR-ABL to proteasome. Expression of Bag1 induced BCR-ABL degradation and growth suppression in Ba/F3 cells when Hsc70 was knocked down with or without CHIP induction. CHIP appears to sort newly synthesized Hsp90-unchaperoned BCR-ABL to the proteasome not only by inhibiting Hsc70 and thereby promoting Bag1 to bind BCR-ABL, but also by ubiquitinating BCR-ABL. Bag1 may direct CHIP/Hsc70-regulated protein triage decisions on BCR-ABL immediately after translation to the degradation pathway.
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28
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Anderson LG, Meeker RB, Poulton WE, Huang DY. Brain distribution of carboxy terminus of Hsc70-interacting protein (CHIP) and its nuclear translocation in cultured cortical neurons following heat stress or oxygen-glucose deprivation. Cell Stress Chaperones 2010; 15:487-95. [PMID: 19953350 PMCID: PMC3006630 DOI: 10.1007/s12192-009-0162-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2008] [Accepted: 11/18/2009] [Indexed: 12/25/2022] Open
Abstract
Carboxy terminus of Hsc70-interacting protein (CHIP) is thought to be a cytoprotective protein with protein quality control roles in neurodegenerative diseases and myocardial ischemia. This study describes the localization of CHIP expression in normal rodent brain and the early CHIP response in primary cultures of cortical neurons following ischemic stress models: heat stress (HS) and oxygen-glucose deprivation (OGD). CHIP was highly expressed throughout the brain, predominantly in neurons. The staining pattern was primarily cytoplasmic, although small amounts were seen in the nucleus. More intense nuclear staining was observed in primary cultured neurons which increased with stress. Nuclear accumulation of CHIP occurred within 5-10 min of HS and decreased to baseline levels or lower by 30-60 min. Decrease in nuclear CHIP at 30-60 min of HS was associated with a sharp increase in delayed cell death. While no changes in cytoplasmic CHIP were observed immediately following OGD, nuclear levels of CHIP increased slightly in response to OGD durations of 30 to 240 min. OGD-induced increases in nuclear CHIP decreased slowly during post-ischemic recovery. Nuclear CHIP decreased earlier in recovery following 120 min of OGD (4 h) than 30 min of OGD (12 h). Significant cell death first appeared between 12 and 24 h after OGD, again suggesting that delayed cell death follows closely behind the disappearance of nuclear CHIP. The ability of CHIP to translocate to and accumulate in the nucleus may be a limiting variable that determines how effectively cells respond to external stressors to facilitate cell survival. Using primary neuronal cell cultures, we were able to demonstrate rapid translocation of CHIP to the nucleus within minutes of heat stress and oxygen-glucose deprivation. An inverse relationship between nuclear CHIP and delayed cell death at 24 h suggests that the decrease in nuclear CHIP following extreme stress is linked to delayed cell death. Our findings of acute changes in subcellular localization of CHIP in response to cellular stress suggest that cellular changes that occur shortly after exposure to stress ultimately impact on the capacity and capability of a cell to recover and survive.
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Affiliation(s)
- Lauren G. Anderson
- Curriculum in Neurobiology, University of North Carolina at Chapel Hill, Chapel Hill, NC USA
| | - Rick B. Meeker
- Curriculum in Neurobiology, University of North Carolina at Chapel Hill, Chapel Hill, NC USA
- Department of Neurology, University of North Carolina at Chapel Hill, CB #7025, Physicians Office Building, Chapel Hill, NC 27599-7025 USA
| | - Winona E. Poulton
- Department of Neurology, University of North Carolina at Chapel Hill, CB #7025, Physicians Office Building, Chapel Hill, NC 27599-7025 USA
| | - David Y. Huang
- Curriculum in Neurobiology, University of North Carolina at Chapel Hill, Chapel Hill, NC USA
- Department of Neurology, University of North Carolina at Chapel Hill, CB #7025, Physicians Office Building, Chapel Hill, NC 27599-7025 USA
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29
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Wu SJ, Wang LC, Yeh CH, Lu CA, Wu SJ. Isolation and characterization of the Arabidopsis heat-intolerant 2 (hit2) mutant reveal the essential role of the nuclear export receptor EXPORTIN1A (XPO1A) in plant heat tolerance. THE NEW PHYTOLOGIST 2010; 186:833-842. [PMID: 20345641 DOI: 10.1111/j.1469-8137.2010.03225.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
*The Arabidopsis heat-intolerant 2 (hit2) mutant was isolated on the basis of its impaired ability to withstand moderate heat stress (37 degrees C). Determination of the genetic mutation that underlies the hit2 thermosensitive phenotype allowed better understanding of the mechanisms by which plants cope with heat stress. *Genetic analysis revealed that hit2 is a single recessive mutation. Map-based cloning was used to identify the hit2 locus. The response of hit2 to other types of heat stress was also investigated to characterize the protective role of HIT2. *hit2 was defective in basal but not in acquired thermotolerance. hit2 was sensitive to methyl viologen-induced oxidative stress, and the survival of hit2 seedlings in response to heat stress was affected by light conditions. The mutated locus was located at the EXPORTIN1A (XPO1A) gene, which encodes a nuclear transport receptor. Two T-DNA insertion lines, xpo1a-1 and xpo1a-3, exhibited the same phenotypes as hit2. *The results provide evidence that Arabidopsis XPO1A is dispensable for normal plant growth and development but is essential for thermotolerance, in part by mediating the protection of plants against heat-induced oxidative stress.
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MESH Headings
- Active Transport, Cell Nucleus/drug effects
- Active Transport, Cell Nucleus/radiation effects
- Adaptation, Physiological/drug effects
- Adaptation, Physiological/genetics
- Adaptation, Physiological/radiation effects
- Arabidopsis/drug effects
- Arabidopsis/genetics
- Arabidopsis/radiation effects
- Arabidopsis Proteins/genetics
- Arabidopsis Proteins/metabolism
- Cell Nucleus/drug effects
- Cell Nucleus/genetics
- Cell Nucleus/metabolism
- Cell Nucleus/radiation effects
- Chromosome Mapping
- Crosses, Genetic
- Gene Expression Regulation, Plant/drug effects
- Gene Expression Regulation, Plant/radiation effects
- Genes, Plant/genetics
- Genes, Recessive/genetics
- Genetic Loci/genetics
- Gentian Violet/pharmacology
- Hot Temperature
- Karyopherins/genetics
- Karyopherins/metabolism
- Light
- Mutation/genetics
- Oxidative Stress/drug effects
- Oxidative Stress/radiation effects
- Phenotype
- Receptors, Cytoplasmic and Nuclear/genetics
- Receptors, Cytoplasmic and Nuclear/metabolism
- Recombination, Genetic/drug effects
- Recombination, Genetic/genetics
- Recombination, Genetic/radiation effects
- Seedlings/drug effects
- Seedlings/growth & development
- Seedlings/radiation effects
- Stress, Physiological/drug effects
- Stress, Physiological/genetics
- Stress, Physiological/radiation effects
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Affiliation(s)
| | | | - Ching-Hui Yeh
- Department of Life Sciences, National Central University, No.300, Jhong-da Road, Jhong-li City, Taoyuan 32001, Taiwan
| | - Chun-An Lu
- Department of Life Sciences, National Central University, No.300, Jhong-da Road, Jhong-li City, Taoyuan 32001, Taiwan
| | - Shaw-Jye Wu
- Department of Life Sciences, National Central University, No.300, Jhong-da Road, Jhong-li City, Taoyuan 32001, Taiwan
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30
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Bański P, Mahboubi H, Kodiha M, Shrivastava S, Kanagaratham C, Stochaj U. Nucleolar targeting of the chaperone hsc70 is regulated by stress, cell signaling, and a composite targeting signal which is controlled by autoinhibition. J Biol Chem 2010; 285:21858-67. [PMID: 20457599 DOI: 10.1074/jbc.m110.117291] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Hsc70s are constitutively synthesized members of the 70-kDa chaperone family; they are essential for viability and conserved among all organisms. When eukaryotic cells recover from stress, hsc70s accumulate in nucleoli by an unknown mechanism. Our studies were undertaken to characterize the signaling events and the targeting sequence required to concentrate hsc70 in the nucleoli of human cells. Here, we show that pharmacological inhibitors of phosphatidylinositol (PI) 3-kinase and MEK kinases as well as protein-tyrosine phosphatases abolished the stress-dependent nucleolar accumulation of hsc70. Furthermore, to identify the hsc70 nucleolar targeting sequence, green fluorescent protein-tagged fusion proteins with defined segments of hsc70 were generated and their subcellular distribution was analyzed in growing cells. These studies demonstrated that residues 225 to 297 serve as a heat-inducible nucleolar targeting signal. This segment directs green fluorescent protein to nucleoli in response to stress, but fails to do so under nonstress conditions. Fine mapping of the nucleolar targeting signal revealed that it has two separable functions. First, residues 225 to 262 direct reporter proteins constitutively to nucleoli, even without stress. Second, segment 263 to 287 functions as an autoinhibitory element that prevents hsc70 from concentrating in nucleoli when cells are not stressed. Taken together, PI 3-kinase and MEK kinase signaling as well as tyrosine dephosphorylation are essential for the accumulation of hsc70 in nucleoli of stressed cells. This process relies on a stress-dependent composite targeting signal that combines multiple functions.
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Affiliation(s)
- Piotr Bański
- Department of Physiology, McGill University, Montreal H3G 1Y6, Canada
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31
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Heat stress cognate 70 host protein as a potential drug target against drug resistance in hepatitis B virus. Antimicrob Agents Chemother 2010; 54:2070-7. [PMID: 20176893 DOI: 10.1128/aac.01764-09] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Heat stress cognate 70 (Hsc70) is a host protein associated with hepatitis B virus (HBV) replication. The goal of this study was to investigate whether Hsc70 could be an anti-HBV drug target. Our results showed that introducing Hsc70 increased HBV replication in HBV(+) human hepatocytes (HepG2.2.15 cells). The coiled-coil region on Hsc70 (nucleotides 1533 to 1608; amino acids 511 to 536) was the key sequence for HBV replication. Knockdown of Hsc70 expression by RNA interference (RNAi) largely inhibited HBV replication with no cytotoxicity to the host. Using an Hsc70 mRNA screening assay, the natural compound oxymatrine (OMTR) was found to be a selective inhibitor for Hsc70 expression. Then, OMTR was used to investigate the potential of Hsc70 as an anti-HBV drug target. OMTR inhibited Hsc70 mRNA expression by 80% and HBV DNA replication by over 60% without causing cytotoxicity. The anti-HBV effect of OMTR appeared to be mediated by destabilizing Hsc70 mRNA. The half-life (T(1/2)) of Hsc70 mRNA decreased by 50% in OMTR-treated hepatocytes. The Hsc70 mRNA 3'-untranslated-region (UTR) sequence was the element responsible for OMTR's destabilization activity. OMTR suppressed HBV de novo synthesis at the reverse transcription stage from pregenomic RNA (pgRNA) to DNA and was active against either wild-type HBV or strains resistant to lamivudine, adefovir, and entecavir. Therefore, host Hsc70 could be a novel drug target against HBV, and OMTR appears to inhibit HBV replication by destabilizing Hsc70 mRNA. As the target is not a viral protein, OMTR is active for either wild-type HBV or strains resistant to reverse transcriptase (RT) inhibitors.
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32
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Mills DR, Haskell MD, Callanan HM, Flanagan DL, Brilliant KE, Yang D, Hixson DC. Monoclonal antibody to novel cell surface epitope on Hsc70 promotes morphogenesis of bile ducts in newborn rat liver. Cell Stress Chaperones 2010; 15:39-53. [PMID: 19415527 PMCID: PMC2866973 DOI: 10.1007/s12192-009-0120-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2008] [Accepted: 04/19/2009] [Indexed: 12/30/2022] Open
Abstract
We previously described a cell surface reactive monoclonal antibody, MAb OC.10, which recognizes an epitope shared by rat fetal liver ductal cells, hepatic progenitor cells, mature cholangiocytes, and hepatocellular carcinomas (HCC). Here, intrasplenic injection of MAb OC.10 into newborn rats was shown by immunofluorescence microscopy to strongly label intrahepatic bile ducts. Furthermore, the in situ labeling of intrahepatic cholangiocytes by injecting MAb OC.10 increased the number of intraportal and intralobular bile ducts with well-defined lumens when compared to IgM-injected control animals. The antigen for MAb OC.10 was identified by mass spectrometry as Hsc70, a constitutively expressed heat shock protein belonging to the HSP70 family. Immunoblot analysis demonstrated that MAb OC.10 reacted with recombinant bovine Hsc70 protein, with protein immunoprecipitated from rat bile duct epithelial (BDE) cell lysates with monoclonal anti-Hsc70 antibody, and with Hsc70-FLAG protein over-expressed in human 293T cells. In addition, Hsc70-specific small interfering RNA reduced the amount of OC.10 antigen expressed in nucleofected BDE cells. Consistent with the specificity of MAb OC.10 for Hsc70, heat shock did not induce OC.10 expression in BDE cells, a characteristic of Hsp70. Immunofluorescence with BDE cells further suggested that MAb OC.10 binds a novel cell surface epitope of Hsc70. This was in contrast to a commercially available monoclonal anti-Hsc70 antibody that showed strong cytosolic reactivity. These findings demonstrate that presentation of the OC.10 epitope differs between cytosolic and surface forms of Hsc70 and may suggest distinct differences in protein conformation or epitope availability determined in part by protein-protein or protein-lipid interactions. Phage display and pepscan analysis mapped the epitope for MAb OC.10 to the N-terminal 340-384 amino acids of the ATPase domain of rat Hsc70. These findings suggest that MAb OC.10 recognizes an epitope on rat Hsc70 when presented on the cell surface that promotes morphogenic maturation of bile ducts in newborn rat liver. Furthermore, since we have shown previously that the OC.10 antigen is expressed on HCC subpopulations with oval cell characteristics, our current results indicate that Hsc70 has the potential to be expressed on the surface of certain tumor cells.
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Affiliation(s)
- David R. Mills
- Department of Medicine, Division of Hematology and Oncology, Rhode Island Hospital/The Warren Alpert Medical School of Brown University, Providence, RI 02903 USA
- Rhode Island Hospital, George Building Room 362, 593 Eddy Street, Providence, RI 02903 USA
| | - Michelle D. Haskell
- Department of Medicine, Division of Hematology and Oncology, Rhode Island Hospital/The Warren Alpert Medical School of Brown University, Providence, RI 02903 USA
| | - Helen M. Callanan
- Department of Medicine, Division of Hematology and Oncology, Rhode Island Hospital/The Warren Alpert Medical School of Brown University, Providence, RI 02903 USA
| | - Donna L. Flanagan
- Department of Medicine, Division of Hematology and Oncology, Rhode Island Hospital/The Warren Alpert Medical School of Brown University, Providence, RI 02903 USA
| | - Kate E. Brilliant
- Department of Medicine, Division of Hematology and Oncology, Rhode Island Hospital/The Warren Alpert Medical School of Brown University, Providence, RI 02903 USA
| | - DongQin Yang
- Department of Medicine, Division of Hematology and Oncology, Rhode Island Hospital/The Warren Alpert Medical School of Brown University, Providence, RI 02903 USA
| | - Douglas C. Hixson
- Department of Medicine, Division of Hematology and Oncology, Rhode Island Hospital/The Warren Alpert Medical School of Brown University, Providence, RI 02903 USA
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33
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Nirdé P, Derocq D, Maynadier M, Chambon M, Basile I, Gary-Bobo M, Garcia M. Heat shock cognate 70 protein secretion as a new growth arrest signal for cancer cells. Oncogene 2009; 29:117-27. [PMID: 19802014 DOI: 10.1038/onc.2009.311] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Earlier studies indicated that density-arrested cancer cells released an unidentified growth inhibitor whose secretion was prevented by overexpression of the lysosomal protease cathepsin D (cath D). In this study, this growth inhibitor was purified by affinity chromatography and identified as the heat shock cognate 70 protein (hsc70) based on its peptide microsequencing and specific antibody recognition. Among intracellular proteins, including other heat shock proteins, only constitutive hsc70 was secreted in response to the high-cell density. Moreover, hsc70 secretion from cancer cells was generated by serum deprivation, whereas its cellular concentration did not change. Prevention of Hsc70 secretion by cath D overexpression was associated with the formation of multilayer cell cultures, thus indicating a loss of contact inhibition. In addition, we showed that supplementing the culture medium with purified hsc70 inhibited cell proliferation in the nanomolar range. Conversely, removal of this extracellular hsc70 from the medium by either retention on ADP-agarose or competition at the Hsc70 binding site restored cell proliferation. Hsc70 appears active in human breast cancer cells and hypersecreted by direct cath D inhibition. These results suggest a new role of this secreted hsc70 chaperone in cell proliferation that might account for the higher tumor growth of cancer cells overexpressing cath D.
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Affiliation(s)
- P Nirdé
- IRCM, institut de Recherche en Cancérologie de Montpellier, Montpellier, France
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34
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Munkonge FM, Amin V, Hyde SC, Green AM, Pringle IA, Gill DR, Smith JWS, Hooley RP, Xenariou S, Ward MA, Leeds N, Leung KY, Chan M, Hillery E, Geddes DM, Griesenbach U, Postel EH, Dean DA, Dunn MJ, Alton EWFW. Identification and functional characterization of cytoplasmic determinants of plasmid DNA nuclear import. J Biol Chem 2009; 284:26978-87. [PMID: 19638341 PMCID: PMC2785383 DOI: 10.1074/jbc.m109.034850] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2009] [Indexed: 01/07/2023] Open
Abstract
Import of exogenous plasmid DNA (pDNA) into mammalian cell nuclei represents a key intracellular obstacle to efficient non-viral gene delivery. This includes access of the pDNA to the nuclei of non-dividing cells where the presence of an intact nuclear membrane is limiting for gene transfer. Here we identify, isolate, and characterize, cytoplasmic determinants of pDNA nuclear import into digitonin-permeabilized HeLa cells. Depletion of putative DNA-binding proteins, on the basis of their ability to bind immobilized pDNA, abolished pDNA nuclear import supporting the critical role of cytoplasmic factors in this process. Elution of pDNA-bound proteins, followed by two-dimensional sodium dodecyl polyacrylamide gel electrophoresis identified several candidate DNA shuttle proteins. We show that two of these, NM23-H2, a ubiquitous c-Myc transcription-activating nucleoside diphosphate kinase, and the core histone H2B can both reconstitute pDNA nuclear import. Further, we demonstrate a significant increase in gene transfer in non-dividing HeLa cells transiently transfected with pDNA containing binding sequences from two of the DNA shuttle proteins, NM23-H2 and the homeobox transcription factor Chx10. These data support the hypothesis that exogenous pDNA binds to cytoplasmic shuttle proteins and is then translocated to the nucleus using the minimal import machinery. Importantly, increasing the binding of pDNA to shuttle proteins by re-engineering reporter plasmids with shuttle binding sequences enhances gene transfer. Increasing the potential for exogenously added pDNA to bind intracellular transport cofactors may enhance the potency of non-viral gene transfer.
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Affiliation(s)
- Felix M Munkonge
- Department of Gene Therapy, National Heart & Lung Institute, Faculty of Medicine, Imperial College London, London SW3 6LR, United Kingdom.
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35
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de Andrade A, Siviero F, Rezende-Teixeira P, Santelli RV, Machado-Santelli GM. Molecular characterization of a putative heat shock protein cognate gene in Rhynchosciara americana. Chromosome Res 2009; 17:935-45. [PMID: 19768564 DOI: 10.1007/s10577-009-9081-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2009] [Accepted: 09/02/2009] [Indexed: 11/24/2022]
Abstract
An hsc70 homologue gene (Rahsc70) of the diptera Rhynchosciara americana was isolated and characterized. We were able to determine the mRNA sequence from an EST of salivary gland cDNA library, and a Rahsc70 cDNA cassette was used as a probe to isolate the genomic region from a genomic library. The mRNA expression of this gene parallels the 2B puff expansion, suggesting its involvement in protein processing, since this larval period corresponds to a high synthetic activity period. During heat shock stress conditions, hsc70 expression decreased. In situ hybridization of polytene chromosomes showed that the Rahsc70 gene is located near the C3 DNA puff. The cellular localization of Hsc70 protein showed this protein in the cytoplasm and in the nucleus.
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Affiliation(s)
- Alexandre de Andrade
- Instituto de Química, Departamento de Bioquímica, Universidade de São Paulo, Av. Prof. Lineu Prestes 748, São Paulo, SP, 05508-900, Brazil
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36
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Chiba T, Maeda G, Kawashiri S, Kato K, Imai K. Epigenetic Loss of Mucosa-Associated Lymphoid Tissue 1 Expression in Patients with Oral Carcinomas. Cancer Res 2009; 69:7216-23. [DOI: 10.1158/0008-5472.can-09-1140] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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37
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Krynetskaia NF, Phadke MS, Jadhav SH, Krynetskiy EY. Chromatin-associated proteins HMGB1/2 and PDIA3 trigger cellular response to chemotherapy-induced DNA damage. Mol Cancer Ther 2009; 8:864-72. [PMID: 19372559 DOI: 10.1158/1535-7163.mct-08-0695] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The identification of new molecular components of the DNA damage signaling cascade opens novel avenues to enhance the efficacy of chemotherapeutic drugs. High-mobility group protein 1 (HMGB1) is a DNA damage sensor responsive to the incorporation of nonnatural nucleosides into DNA; several nuclear and cytosolic proteins are functionally integrated with HMGB1 in the context of DNA damage response. The functional role of HMGB1 and HMGB1-associated proteins (high-mobility group protein B2, HMGB2; glyceraldehyde-3-phosphate dehydrogenase, GAPDH; protein disulfide isomerase family A member 3, PDIA3; and heat shock 70 kDa protein 8, HSPA8) in DNA damage response was assessed in human carcinoma cells A549 and UO31 by transient knockdown with short interfering RNAs. Using the cell proliferation assay, we found that knockdown of HMGB1-associated proteins resulted in 8-fold to 50-fold decreased chemosensitivity of A549 cells to cytarabine. Western blot analysis and immunofluorescent microscopy were used to evaluate genotoxic stress markers in knocked-down cancer cells after 24 to 72 hours of incubation with 1 micromol/L of cytarabine. Our results dissect the roles of HMGB1-associated proteins in DNA damage response: HMGB1 and HMGB2 facilitate p53 phosphorylation after exposure to genotoxic stress, and PDIA3 has been found essential for H2AX phosphorylation (no gamma-H2AX accumulated after 24-72 hours of incubation with 1 micromol/L of cytarabine in PDIA3 knockdown cells). We conclude that phosphorylation of p53 and phosphorylation of H2AX occur in two distinct branches of the DNA damage response. These findings identify new molecular components of the DNA damage signaling cascade and provide novel promising targets for chemotherapeutic intervention.
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Affiliation(s)
- Natalia F Krynetskaia
- Temple University School of Pharmacy, 3307 North Broad Street, Philadelphia, PA 19140, USA
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38
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Cho EK, Choi YJ. A nuclear-localized HSP70 confers thermoprotective activity and drought-stress tolerance on plants. Biotechnol Lett 2009; 31:597-606. [PMID: 19034388 DOI: 10.1007/s10529-008-9880-5] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2008] [Revised: 11/05/2008] [Accepted: 11/10/2008] [Indexed: 12/23/2022]
Abstract
To investigate the function of nuclear-localized plant HSP70, we used NtHSP70-1 isolated from Nicotiana tabacum. The subcellular localization of NtHSP70-1 was identified by fluorescence microscopy for NtHSP70-1/GFP or smGFP fusion proteins in onion epidermal cells, obtained using particle gun bombardment. To analyze the drought-stress tolerance and thermoprotective role of NtHSP70-1, we obtained transgenic tobacco plants that constitutively expressed elevated levels of NtHSP70-1 as well as transgenic plants containing either the vector alone or else having NtHSP70-1 in the antisense orientation. From analysis for genomic DNA in transgenic seedlings after heat stress, NtHSP70-1 helps to prevent the fragmentation and degradation of nuclear DNA during heat stress. In addition, seedlings constitutively overexpressing NtHSP70-1 grew to be healthy plants, whereas transgenic vector or antisense seedlings resulted in death after heat-/drought-stress.
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Affiliation(s)
- Eun Kyung Cho
- Department of Bio-Food Materials, College of Medical Life Science, Silla University, Busan 617-736, South Korea.
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39
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Imamura Y, Fujigaki Y, Oomori Y, Usui S, Wang PL. Cooperation of salivary protein histatin 3 with heat shock cognate protein 70 relative to the G1/S transition in human gingival fibroblasts. J Biol Chem 2009; 284:14316-25. [PMID: 19321452 DOI: 10.1074/jbc.m807278200] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Histatins, a family of salivary proteins, have antimicrobial activity. Candida albicans, which is killed by histatins, induces oral candidiasis in individuals with compromised immune systems. Although the functional significance of histatins has been documented, their biological and physiological functions against host cells have not been clarified. In this study, we found that histatin 3, a member of the histatin family, binds to heat shock cognate protein 70 (HSC70). These proteins were co-localized in the cytoplasm and nucleus in human gingival fibroblasts following non-heat and heat shock. Histatin 3 induced stimulation of DNA synthesis and cell survival in human gingival fibroblasts in a dose-dependent manner. This DNA synthesis was found to be dependent on HSC70 by knockdown experiments. The effect of heat shock on DNA synthesis induced by histatin 3 was approximately 2-fold higher than that of non-heat shock. When the histatin 3 uptake into cells was inhibited by monodansylcadaverine or when histatin 3 binding to HSC70 was precluded by 15-deoxyspergualin, DNA synthesis by histatin 3 was approximately 2-fold less than that without monodansylcadaverine or 15-deoxyspergualin. Although HSC70 directly bound to p27(Kip1) (a cyclin-dependent kinase inhibitor), histatin 3 increased the binding between those proteins but not with a peptide capable of binding to HSC70. Moreover histatin 3 prevented ATP-dependent dissociation of HSC70-p27(Kip1). ATP was unable to form a histatin 3-HSC70(D10N)-p27(Kip1) complex (HSC70(D10N) is a mutant attenuating ATPase activity). These findings suggest that histatin 3 may be involved in cell proliferation through the regulation of HSC70 and p27(Kip1) in oral cells.
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Affiliation(s)
- Yasuhiro Imamura
- Departments of Pharmacology, Community Dentistry, Special Patient and Oral Care, and Periodontology, Matsumoto Dental University, 1780 Gohbara, Hiro-oka, Shiojiri, Nagano 399-0781, Japan
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40
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Hayashi Y, Horie M, Daito T, Honda T, Ikuta K, Tomonaga K. Heat shock cognate protein 70 controls Borna disease virus replication via interaction with the viral non-structural protein X. Microbes Infect 2009; 11:394-402. [PMID: 19397879 DOI: 10.1016/j.micinf.2009.01.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2008] [Revised: 01/13/2009] [Accepted: 01/17/2009] [Indexed: 11/18/2022]
Abstract
Borna disease virus (BDV) is a non-segmented, negative-sense RNA virus and has the property of persistently infecting the cell nucleus. BDV encodes a 10-kDa non-structural protein, X, which is a negative regulator of viral polymerase activity but is essential for virus propagation. Recently, we have demonstrated that interaction of X with the viral polymerase cofactor, phosphoprotein (P), facilitates translocation of P from the nucleus to the cytoplasm. However, the mechanism by which the intracellular localization of X is controlled remains unclear. In this report, we demonstrate that BDV X interacts with the 71kDa molecular chaperon protein, Hsc70. Immunoprecipitation assays revealed that Hsc70 associates with the same region of X as P and, interestingly, that expression of P interferes competitively with the interaction between X and Hsc70. A heat shock experiment revealed that BDV X translocates into the nucleus, dependent upon the nuclear accumulation of Hsc70. Furthermore, we show that knockdown of Hsc70 by short interfering RNA decreases the nuclear localization of both X and P and markedly reduces the expression of viral genomic RNA in persistently infected cells. These data indicate that Hsc70 may be involved in viral replication by regulating the intracellular distribution of X.
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Affiliation(s)
- Yohei Hayashi
- Department of Virology, Research Institute for Microbial Diseases (BIKEN), Osaka University, 3-1 Yamadaoka, Suita, Osaka 565-0871, Japan
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41
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Scieglińska D, Pigłowski W, Mazurek A, Małusecka E, Zebracka J, Filipczak P, Krawczyk Z. The HspA2 protein localizes in nucleoli and centrosomes of heat shocked cancer cells. J Cell Biochem 2008; 104:2193-206. [PMID: 18452162 DOI: 10.1002/jcb.21778] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The human HSPA2 gene, which belongs to the HSP70 family of heat shock genes, is a counterpart of rodent testis-specific HspA2 gene. Rodent genes are expressed mainly in pachytene spermatocytes, while transcripts of human HSPA2 gene have been detected in various normal somatic tissues, albeit translation of the messenger RNA into corresponding protein has not been yet unambiguously demonstrated, except for several cancer cell lines. The aim of our work, a first step in search for HspA2 function in cancer cells, was to establish its intracellular localization at physiological temperature and during heat shock. First, we used qRT-PCR and a highly specific antibody to select cell lines with the highest expression of the HspA2 protein, which turned out to be A549 and NCI-H1299 lines originating from non-small cell lung carcinoma (NSCLC). Significant expression of the HspA2 was also detected by immunohistochemistry in primary NSCLC specimens. Intracellular localization of the HspA2 was studied using both the specific anti-HspA2 polyclonal antibody and transfection of cells with fusion proteins HspA2-EGFP and mRFP-HspA2. We found that, at physiological temperature, the HspA2 was localized primarily in cytoplasm whereas, during heat shock, localization shifted to nucleus and nucleoli. Moreover, we demonstrate that in heat-shocked cells HspA2 accumulated in centrosomes. Our results suggest that the HspA2, like Hsp70 protein, can be involved in protecting nucleoli and centrosomes integrity in cancer cells subjected to heat shock and, possibly, other cellular stressors.
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Affiliation(s)
- Dorota Scieglińska
- Department of Tumor Biology, Maria Skłodowska-Curie Memorial Cancer Center and Institute of Oncology, Gliwice Branch, Wybrzeze Armii Krajowej 15, 44-101 Gliwice, Poland.
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42
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Hamamoto T, Suzuki K, Yamauchi M, Kodama S, Sasaki H, Watanabe M. p53 status-dependent sensitization of human tumour cells to hyperthermia by plant flavonol. Int J Hyperthermia 2008; 24:415-24. [PMID: 18608579 DOI: 10.1080/02656730802064613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
PURPOSE Quercetin (QCT), an important flavonol, is known to sensitize tumour cells to hyperthermia by suppressing heat shock protein 72 (Hsp72) induction, and is also reported to inhibit p53 accumulation. This study was conducted to examine the effects of QCT on the heat sensitivities of human tumour cell lines with different p53 statuses. MATERIAL AND METHODS Cell lines derived from human cancers and p53-inducible cells were used. After heat treatment at 43 degrees C for 2 h with or without QCT, cell survival was determined in a clonogenic assay. The cellular and nuclear content of Hsp72 as well as that of p53 was determined by Western blotting analysis. RESULTS Treatment of cells with 150 microM QCT, which completely abolished Hsp72 induction, potentiated the lethal effects of hyperthermia in all tumour cell lines. Particularly, remarkable enhancement of cell death was observed in tumour cell lines having little or no p53 proteins. Although nuclear translocation of Hsp72 is induced by hyperthermia, it was significantly compromised in p53-deficient cells. CONCLUSIONS These results indicate that p53 is a component for nuclear accumulation of Hsp72; therefore, p53 status is an important determinant of the sensitization of human tumour cells to hyperthermia by QCT.
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Affiliation(s)
- Tomoyuki Hamamoto
- Department of Hospital Pharmacy, Nagasaki University School of Medicine, Nagasaki, Japan
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Tkach JM, Glover JR. Nucleocytoplasmic trafficking of the molecular chaperone Hsp104 in unstressed and heat-shocked cells. Traffic 2007; 9:39-56. [PMID: 17973656 DOI: 10.1111/j.1600-0854.2007.00666.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Hsp104 is a molecular chaperone in yeast that restores solubility and activity to inactivated proteins after severe heat shock. We investigated the mechanisms that influence Hsp104 subcellular distribution in both unstressed and heat-shocked cells. In unstressed cells, Hsp104 and a green fluorescent protein-Hsp104 fusion protein were detected in both the nucleus and the cytoplasm. We demonstrate that a 17-amino-acid sequence of Hsp104 nuclear localization sequence 17 (NLS17) is sufficient to target a reporter molecule to the nucleus and is also necessary for normal Hsp104 subcellular distribution. The nuclear targeting function of NLS17 is genetically dependent on KAP95 and KAP121. In addition, wild-type Hsp104, but not an NLS17-mutated Hsp104 variant, accumulated in the nucleus of cells depleted for the general export factor Xpo1. Interestingly, severe, nonlethal heat shock enhances the nuclear levels of Hsp104 in an NLS17-independent manner. Under these conditions, we demonstrate that karyopherin-mediated nuclear transport is impaired, while the integrity of the nuclear-cytoplasmic barrier remains intact. Based on these observations, we propose that Hsp104 continues to access the nucleus during severe heat shock using a karyopherin-independent mechanism.
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Affiliation(s)
- Johnny M Tkach
- Department of Biochemistry, University of Toronto, Room 5302, Medical Sciences Building, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada
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Browne CL, Swan JB, Rankin EE, Calvert H, Griffiths S, Tytell M. Extracellular heat shock protein 70 has novel functional effects on sea urchin eggs and coelomocytes. ACTA ACUST UNITED AC 2007; 210:1275-87. [PMID: 17371926 DOI: 10.1242/jeb.02743] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Numerous reports document that the 70 kDa heat shock proteins are not only intracellular proteins but are also present in blood and other extracellular compartments. How they affect cell function from the extracellular space remains unclear. Using two well-characterized cell types from the sea urchin, we show that extracellular mixtures of the constitutive and inducible forms of the 70 kDa heat shock proteins (Hsc70 and Hsp70, respectively) have dramatic effects on initiation of cell division in fertilized eggs and on the clotting reaction of hypotonically stressed coelomocytes. In suspensions of fertilized eggs to which Hsc70 or a 2:3 mixture of Hsc and Hsp70 was added, progression to the first mitotic division was accelerated. Evidence is provided that the extracellular Hsc70 passes into the egg cells in an unconventional manner, being distributed through the cytoplasm, and that it may alter the intracellular signaling cascade initiated by sperm penetration. In coelomocytes that were stimulated by hypotonic shock to mimic injury, the spreading reaction of the clotting response was significantly inhibited when either Hsp70 or Hsc70 was in the medium. These results suggest that the presence of Hsc and/or Hsp70 in the extracellular fluid may promote mitosis of dividing cells and suppress the reactivity of immune system cells.
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Affiliation(s)
- Carole L Browne
- Department of Biology, Wake Forest University, Winston-Salem, NC 27109, USA.
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Saito Y, Yamagishi N, Hatayama T. Different localization of Hsp105 family proteins in mammalian cells. Exp Cell Res 2007; 313:3707-17. [PMID: 17643418 DOI: 10.1016/j.yexcr.2007.06.009] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2007] [Revised: 05/18/2007] [Accepted: 06/10/2007] [Indexed: 11/18/2022]
Abstract
Hsp105alpha and Hsp105beta of the HSP105 family are alternatively spliced products derived from an hsp 105 gene transcript. Hsp105alpha is constitutively expressed and also induced by various stress, whereas Hsp105beta, lacking 44 amino acids from Hsp105alpha, is specifically expressed during mild heat shock. Although Hsp105alpha is shown to localize in the cytoplasm of mammalian cells, cellular localization of Hsp105beta is not known. In this study, we showed that Hsp105beta localized in the nucleus of cells in contrast to cytoplasmic Hsp105alpha, suggesting that these proteins function in different cellular compartments of cells. Using deletion and substitution mutants of Hsp105alpha and Hsp105beta, we revealed that these proteins had a functional nuclear localization signal (NLS) and a nuclear export signal (NES). Furthermore, Hsp105alpha accumulated in the nucleus of cells when treated with leptomycin B, a specific inhibitor of NES-dependent nuclear export. siRNA for importin beta, an essential component for NLS-dependent nuclear transport, inhibited the nuclear localization of Hsp105beta. Furthermore, the 44 amino acids sequence found in Hsp105alpha but not in Hsp105beta suppressed the NLS activity. Thus, the different localization of Hsp105alpha and Hsp105beta is suggested to be due to the suppressed NLS activity in Hsp105alpha.
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Affiliation(s)
- Youhei Saito
- Department of Biochemistry, Kyoto Pharmaceutical University, 5 Nakauchi-cho, Misasagi, Yamashina-ku, Kyoto 607-8414, Japan
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Heikkila JJ, Kaldis A, Morrow G, Tanguay RM. The use of the Xenopus oocyte as a model system to analyze the expression and function of eukaryotic heat shock proteins. Biotechnol Adv 2007; 25:385-95. [PMID: 17459646 DOI: 10.1016/j.biotechadv.2007.03.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2007] [Revised: 03/21/2007] [Accepted: 03/21/2007] [Indexed: 11/26/2022]
Abstract
The analysis of the expression and function of heat shock protein (hsp) genes, a class of molecular chaperones, has been greatly aided by studies carried out with Xenopus oocytes. The large size of the oocyte facilitates microinjection of DNA, mRNA or protein, permits manual dissection of nuclei, and allows certain assays to be performed with single oocytes. These and other characteristics were useful in identifying the cis- and trans-acting factors involved in hsp gene transcription as well as the role of chaperones and co-chaperones in the repression and activation of heat shock factor. Xenopus oocytes were used to examine heat shock protein (HSP) molecular chaperone function as well as their involvement in intracellular trafficking, maturation, and secretion of protein. Possible new areas of research with this system include the role of membranes in the heat shock response, involvement of HSPs in viral replication and maturation, and in vivo NMR spectroscopy of microinjected HSPs.
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Affiliation(s)
- John J Heikkila
- Department of Biology, University of Waterloo, Waterloo, ON, Canada N2L 3G1.
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Widlak W, Vydra N, Malusecka E, Dudaladava V, Winiarski B, Scieglińska D, Widlak P. Heat shock transcription factor 1 down-regulates spermatocyte-specific 70 kDa heat shock protein expression prior to the induction of apoptosis in mouse testes. Genes Cells 2007; 12:487-99. [PMID: 17397396 DOI: 10.1111/j.1365-2443.2007.01069.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Expression of constitutively active heat shock transcription factor 1 (HSF1) in mouse spermatocytes induces apoptosis and leads to male infertility. We report here that prior to the onset of massive apoptosis caused by expression of active HSF1 in spermatocytes a marked reduction in spermatocyte-specific Hsp70.2 mRNA and protein levels occurs. In addition, HSP70.2 protein relocalizes from a predominant cytoplasmic to a nuclear position in developing spermatocytes that express active HSF1. Later in the developmental stages, cells undergoing HSF1-induced apoptosis essentially lack the HSP70.2 protein. The down-regulation of Hsp70.2 gene expression by HSF1 is paradoxical because HSF1 is the prototypical activator of HSP genes. Furthermore, HSF1-mediated repression neither involved a heat shock element (HSE)-like sequence adjacent to the Hsp70.2 gene nor were Hsp70.2 promoter sequences associated directly with HSF1. Interestingly, other spermatocyte- and spermatid-specific transcripts are also down-regulated in testes of transgenic mice expressing active HSF1, suggesting involvement of a putative HSF1-dependent block of development of spermatogenic cells. Importantly however, transcription of the Hsp70.2 gene is down-regulated in testes of wild-type mice subjected to a hyperthermia that induces transient activation of HSF1, indicating that the spermatocyte-specific activity of HSF1 might misdirect a network of transcription factors required for proper regulation of Hsp70.2.
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Affiliation(s)
- Wieslawa Widlak
- Department of Tumor Biology, Maria Sklodowksa-Curie Memorial Cancer Center and Institute of Oncology, Gliwice Branch, 44-101 Gliwice, Poland.
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Abstract
The nucleolus is a dynamic subnuclear structure that is crucial to the successful functioning of a cell. Its functions include ribosomal RNA synthesis, cell growth and cell-cycle control as well as responding to cellular stress. Recent studies show that the nucleolus is not a steady-state structure but instead is made up of numerous protein–protein and protein–nucleic-acid interactions that are constantly changing in response to the metabolic conditions of the cell. Many different viruses target the nucleolus to disrupt host-cell function and to recruit cellular proteins to aid in virus replication. The study of viral-protein trafficking to the nucleolus and the interaction of viral proteins with nucleolar proteins is providing many insights into the cell biology of the nucleolus. Because the nucleolus is fundamental to the life cycle of many viruses, disrupting the interaction between the nucleolus and the virus could lead to the design of novel therapeutic strategies.
RNA viruses, particularly positive-strand RNA viruses, interact with the nucleolus to usurp host-cell functions and recruit nucleolar proteins to facilitate virus replication. Here, Julian Hiscox reviews the latest data on RNA-virus interactions with this dynamic subnuclear structure. The nucleolus is a dynamic subnuclear structure with roles in ribosome subunit biogenesis, mediation of cell-stress responses and regulation of cell growth. The proteome and structure of the nucleolus are constantly changing in response to metabolic conditions. RNA viruses interact with the nucleolus to usurp host-cell functions and recruit nucleolar proteins to facilitate virus replication. Investigating the interactions between RNA viruses and the nucleolus will facilitate the design of novel anti-viral therapies, such as recombinant vaccines and therapeutic molecular interventions, and also contribute to a more detailed understanding of the cell biology of the nucleolus.
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Affiliation(s)
- Julian A Hiscox
- Institute of Molecular and Cellular Biology, Faculty of Biological Sciences, and Astbury Centre for Structural Molecular Biology, Garstang Building, University of Leeds, Leeds, LS2 9JT, UK.
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Haag Breese E, Uversky VN, Georgiadis MM, Harrington MA. The disordered amino-terminus of SIMPL interacts with members of the 70-kDa heat-shock protein family. DNA Cell Biol 2007; 25:704-14. [PMID: 17233114 DOI: 10.1089/dna.2006.25.704] [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: 11/12/2022] Open
Abstract
The p65 coactivator SIMPL is a small protein that lacks any conserved domains of known function. To better understand regulation of SIMPL activity, we sought to identify novel SIMPL interacting proteins using mass spectrometry analysis of SIMPL containing complexes. Two members of the 70-kDa heat-shock protein family, Hsp70 and Hsc70, were identified as SIMPL binding proteins. Subsequent immunocomplexing assays confirmed this interaction and demonstrated that the amino-terminus of SIMPL is required for this interaction. Using a combination of amino acid composition analysis, PONDR VL-XT prediction, charge-hydropathy plots, and cumulative distribution functions, the amino-terminal region of both mouse and human SIMPL proteins was predicted to be intrinsically disordered. These data, taken together, suggest that Hsp70/Hsc70 bind the intrinsically disordered amino-terminal region of SIMPL to stabilize the protein and thereby regulate its activity. Understanding the regulation of SIMPL through its interaction with Hsp70/Hsc70 may serve as a novel means of modulating tumor necrosis factor alpha signaling.
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Affiliation(s)
- Erin Haag Breese
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indiana University Cancer Center, Indianapolis, Indiana 46220, USA
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Watanabe K, Fuse T, Asano I, Tsukahara F, Maru Y, Nagata K, Kitazato K, Kobayashi N. Identification of Hsc70 as an influenza virus matrix protein (M1) binding factor involved in the virus life cycle. FEBS Lett 2006; 580:5785-90. [PMID: 17022977 DOI: 10.1016/j.febslet.2006.09.040] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2006] [Revised: 09/13/2006] [Accepted: 09/15/2006] [Indexed: 12/17/2022]
Abstract
Influenza virus matrix protein 1 (M1) has been shown to play a crucial role in the virus replication, assembly and budding. We identified heat shock cognate protein 70 (Hsc70) as a M1 binding protein by immunoprecipitation and MALDI-TOF MS. The C terminal domain of M1 interacts with Hsc70. We found that Hsc70 does not correlate with the transport of M1 to the nucleus, however, it does inhibit the nuclear export of M1 and NP, thus resulting in the inhibition of viral production. This is the first demonstration that Hsc70 is directly associated with M1 and therefore is required for viral production.
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Affiliation(s)
- Ken Watanabe
- Laboratory of Molecular Biology of Infectious Agents, Graduate School of Biomedical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan
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