1
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Hsp70/Hsp90 Organising Protein (Hop): Coordinating Much More than Chaperones. Subcell Biochem 2023; 101:81-125. [PMID: 36520304 DOI: 10.1007/978-3-031-14740-1_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The Hsp70/Hsp90 organising protein (Hop, also known as stress-inducible protein 1/STI1/STIP1) has received considerable attention for diverse cellular functions in both healthy and diseased states. There is extensive evidence that intracellular Hop is a co-chaperone of the major chaperones Hsp70 and Hsp90, playing an important role in the productive folding of Hsp90 client proteins, although recent evidence suggests that eukaryotic Hop is regulatory within chaperone complexes rather than essential. Consequently, Hop is implicated in many key signalling pathways, including aberrant pathways leading to cancer. Hop is also secreted, and it is now well established that Hop interacts with the prion protein, PrPC, to mediate multiple signalling events. The intracellular and extracellular forms of Hop most likely represent two different isoforms, although the molecular determinants of these divergent functions are yet to be identified. There is also a growing body of research that reports the involvement of Hop in cellular activities that appear independent of either chaperones or PrPC. While the various cellular functions of Hop have been described, its biological function remains elusive. However, recent knockout studies in mammals suggest that Hop has an important role in embryonic development. This review provides a critical overview of the latest molecular, cellular and biological research on Hop, critically evaluating its function in healthy systems and how this function is adapted in diseased states.
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2
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JAK2-Mediated Phosphorylation of Stress-Induced Phosphoprotein-1 (STIP1) in Human Cells. Int J Mol Sci 2022; 23:ijms23052420. [PMID: 35269562 PMCID: PMC8910420 DOI: 10.3390/ijms23052420] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 02/19/2022] [Accepted: 02/20/2022] [Indexed: 11/30/2022] Open
Abstract
Stress-induced phosphoprotein-1 (STIP1)—a heat shock protein (HSP)70/HSP90 adaptor protein—is commonly overexpressed in malignant cells, where it controls proliferation via multiple signaling pathways, including JAK2/STAT3. We have previously shown that STIP1 stabilizes the protein tyrosine kinase JAK2 in cancer cells via HSP90 binding. In this study, we demonstrate that STIP1 may act as a substrate for JAK2 and that phosphorylation of tyrosine residues 134 and 152 promoted STIP1 protein stability, induced its nuclear-cytoplasmic shuttling, and promoted its secretion into the extracellular space. We also found that JAK2-mediated STIP1 phosphorylation enhanced cell viability and increased resistance to cisplatin-induced cell death. Conversely, interference STIP1 with JAK2 interaction—attained either through site-directed mutagenesis or the use of cell-penetrating peptides—decreased JAK2 protein levels, ultimately leading to cell death. On analyzing human ovarian cancer specimens, JAK2 and STIP1 expression levels were found to be positively correlated with each other. Collectively, these results indicate that JAK2-mediated phosphorylation of STIP-1 is critical for sustaining the JAK2/STAT3 signaling pathway in cancer cells.
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3
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Dahiya V, Rutz DA, Moessmer P, Mühlhofer M, Lawatscheck J, Rief M, Buchner J. The switch from client holding to folding in the Hsp70/Hsp90 chaperone machineries is regulated by a direct interplay between co-chaperones. Mol Cell 2022; 82:1543-1556.e6. [PMID: 35176233 DOI: 10.1016/j.molcel.2022.01.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 11/23/2021] [Accepted: 01/19/2022] [Indexed: 12/20/2022]
Abstract
Folding of stringent clients requires transfer from Hsp70 to Hsp90. The co-chaperone Hop physically connects the chaperone machineries. Here, we define its role from the remodeling of Hsp70/40-client complexes to the mechanism of client transfer and the conformational switching from stalled to active client-processing states of Hsp90. We show that Hsp70 together with Hsp40 completely unfold a stringent client, the glucocorticoid receptor ligand-binding domain (GR-LBD) in large assemblies. Hop remodels these for efficient transfer onto Hsp90. As p23 enters, Hsp70 leaves the complex via switching between binding sites in Hop. Current concepts assume that to proceed to client folding, Hop dissociates and the co-chaperone p23 stabilizes the Hsp90 closed state. In contrast, we show that p23 functionally interacts with Hop, relieves the stalling Hsp90-Hop interaction, and closes Hsp90. This reaction allows folding of the client and is thus the key regulatory step for the progression of the chaperone cycle.
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Affiliation(s)
- Vinay Dahiya
- Center for Protein Assemblies and Department Chemie, Technische Universität München, München, Germany
| | - Daniel Andreas Rutz
- Center for Protein Assemblies and Department Chemie, Technische Universität München, München, Germany
| | - Patrick Moessmer
- Center for Protein Assemblies and Department Physik, Technische Universität München, München, Germany
| | - Moritz Mühlhofer
- Center for Protein Assemblies and Department Chemie, Technische Universität München, München, Germany
| | - Jannis Lawatscheck
- Center for Protein Assemblies and Department Chemie, Technische Universität München, München, Germany
| | - Matthias Rief
- Center for Protein Assemblies and Department Physik, Technische Universität München, München, Germany
| | - Johannes Buchner
- Center for Protein Assemblies and Department Chemie, Technische Universität München, München, Germany.
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4
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Liu M, Zaman R, Sawczak V, Periasamy A, Sun F, Zaman K. S-nitrosothiols signaling in cystic fibrosis airways. J Biosci 2021. [DOI: 10.1007/s12038-021-00223-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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5
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Makumire S, Zininga T, Vahokoski J, Kursula I, Shonhai A. Biophysical analysis of Plasmodium falciparum Hsp70-Hsp90 organising protein (PfHop) reveals a monomer that is characterised by folded segments connected by flexible linkers. PLoS One 2020; 15:e0226657. [PMID: 32343703 PMCID: PMC7188212 DOI: 10.1371/journal.pone.0226657] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 04/03/2020] [Indexed: 12/20/2022] Open
Abstract
Plasmodium falciparum causes the most lethal form of malaria. The cooperation of heat shock protein (Hsp) 70 and 90 is thought to facilitate folding of select group of cellular proteins that are crucial for cyto-protection and development of the parasites. Hsp70 and Hsp90 are brought into a functional complex that allows substrate exchange by stress inducible protein 1 (STI1), also known as Hsp70-Hsp90 organising protein (Hop). P. falciparum Hop (PfHop) co-localises and occurs in complex with the parasite cytosolic chaperones, PfHsp70-1 and PfHsp90. Here, we characterised the structure of recombinant PfHop using synchrotron radiation circular dichroism (SRCD) and small-angle X-ray scattering. Structurally, PfHop is a monomeric, elongated but folded protein, in agreement with its predicted TPR domain structure. Using SRCD, we established that PfHop is unstable at temperatures higher than 40°C. This suggests that PfHop is less stable at elevated temperatures compared to its functional partner, PfHsp70-1, that is reportedly stable at temperatures as high as 80°C. These findings contribute towards our understanding of the role of the Hop-mediated functional partnership between Hsp70 and Hsp90.
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Affiliation(s)
- Stanley Makumire
- Department of Biochemistry, School of Mathematical & Natural Sciences, University of Venda, Thohoyandou, South Africa
| | - Tawanda Zininga
- Department of Biochemistry, School of Mathematical & Natural Sciences, University of Venda, Thohoyandou, South Africa
- Department of Biochemistry, Stellenbosch University, Stellenbosch, South Africa
| | - Juha Vahokoski
- Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Inari Kursula
- Department of Biomedicine, University of Bergen, Bergen, Norway
- Biocenter Oulu & Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
| | - Addmore Shonhai
- Department of Biochemistry, School of Mathematical & Natural Sciences, University of Venda, Thohoyandou, South Africa
- * E-mail:
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6
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Kausar S, Abbas MN, Yang L, Cui H. Biotic and abiotic stress induces the expression of Hsp70/90 organizing protein gene in silkworm, Bombyx mori. Int J Biol Macromol 2020; 143:610-618. [DOI: 10.1016/j.ijbiomac.2019.12.067] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 12/08/2019] [Accepted: 12/08/2019] [Indexed: 01/29/2023]
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7
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Associations between a single nucleotide polymorphism of stress-induced phosphoprotein 1 and endometriosis/adenomyosis. Taiwan J Obstet Gynecol 2018; 57:270-275. [DOI: 10.1016/j.tjog.2018.03.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/14/2018] [Indexed: 02/06/2023] Open
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8
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Stress-induced phosphoprotein 1 acts as a scaffold protein for glycogen synthase kinase-3 beta-mediated phosphorylation of lysine-specific demethylase 1. Oncogenesis 2018; 7:31. [PMID: 29593255 PMCID: PMC5874249 DOI: 10.1038/s41389-018-0040-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Revised: 02/10/2018] [Accepted: 02/20/2018] [Indexed: 12/17/2022] Open
Abstract
Stress-induced phosphoprotein 1 (STIP1)-a co-chaperone of heat shock proteins-promotes cell proliferation and may act as an oncogenic factor. Similarly, glycogen synthase kinase-3 beta (GSK3β)-mediated phosphorylation of lysine-specific demethylase 1 (LSD1)-an epigenetic regulator-can contribute to the development of an aggressive cell phenotype. Owing to their ability to tether different molecules into functional complexes, scaffold proteins have a key role in the regulation of different signaling pathways in tumorigenesis. Here, we show that STIP1 acts as a scaffold promoting the interaction between LSD1 and GSK3β. Specifically, the TPR1 and TPR2B domains of STIP1 are capable of binding with the AOL domain of LSD1, whereas the TPR2A and TPR2B domains of STIP1 interact with the kinase domain of GSK3β. We also demonstrate that STIP1 is required for GSK3β-mediated LSD1 phosphorylation, which promoted LSD1 stability and enhanced cell proliferation. After transfection of cancer cells with double-mutant (S707A/S711A) LSD1, subcellular localization analysis revealed that LSD1 was translocated from the nucleus to the cytoplasm. In vitro experiments also showed that the LSD1 inhibitor SP2509 and the GSK3β inhibitor LY2090314 acted synergistically to induce cancer cell death. Finally, the immunohistochemical expression of STIP1 and LSD1 showed a positively correlation in human cancer specimens. In summary, our data provide mechanistic insights into the role of STIP1 in human tumorigenesis by showing that it serves as a scaffold for GSK3β-mediated LSD1 phosphorylation. The combination of LSD1 and GSK3β inhibitors may exert synergistic antitumor effects and deserves further scrutiny in preclinical studies.
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9
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Tsai CL, Chao A, Jung SM, Tsai CN, Lin CY, Chen SH, Sue SC, Wang TH, Wang HS, Lai CH. Stress-induced phosphoprotein-1 maintains the stability of JAK2 in cancer cells. Oncotarget 2018; 7:50548-50563. [PMID: 27409672 PMCID: PMC5226602 DOI: 10.18632/oncotarget.10500] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Accepted: 06/17/2016] [Indexed: 01/05/2023] Open
Abstract
Overexpression of stress-induced phosphoprotein 1 (STIP1) − a co-chaperone of heat shock protein (HSP) 70/HSP90 – and activation of the JAK2-STAT3 pathway occur in several tumors. Combined treatment with a HSP90 inhibitor and a JAK2 inhibitor exert synergistic anti-cancer effects. Here, we show that STIP1 stabilizes JAK2 protein in ovarian and endometrial cancer cells. Knock-down of endogenous STIP1 decreased JAK2 and phospho-STAT3 protein levels. The N-terminal fragment of STIP1 interacts with the N-terminus of JAK2, whereas the C-terminal DP2 domain of STIP1 mediates the interaction with HSP90 and STAT3. A peptide fragment in the DP2 domain of STIP1 (peptide 520) disrupted the interaction between STIP1 and HSP90 and induced cell death through JAK2 suppression. In an animal model, treatment with peptide 520 inhibited tumor growth. In summary, STIP1 modulates the function of the HSP90-JAK2-STAT3 complex. Peptide 520 may have therapeutic potential in the treatment of JAK2-overexpressing tumors.
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Affiliation(s)
- Chia-Lung Tsai
- Genomic Medicine Research Core Laboratory, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Angel Chao
- Genomic Medicine Research Core Laboratory, Chang Gung Memorial Hospital, Taoyuan, Taiwan.,Department of Obstetrics and Gynecology, Chang Gung Memorial Hospital and Chang Gung University, Taoyuan, Taiwan
| | - Shih-Ming Jung
- Department of Pathology, Chang Gung Memorial Hospital and Chang Gung University, Taoyuan, Taiwan
| | - Chi-Neu Tsai
- Graduate Institute of Clinical Medical Sciences, Chang Gung University, Taoyuan, Taiwan
| | - Chiao-Yun Lin
- Department of Obstetrics and Gynecology, Chang Gung Memorial Hospital and Chang Gung University, Taoyuan, Taiwan
| | - Shun-Hua Chen
- Department of Obstetrics and Gynecology, Chang Gung Memorial Hospital and Chang Gung University, Taoyuan, Taiwan.,Graduate Institute of Biomedical Science, School of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Shih-Che Sue
- Department of Life Sciences, Institute of Bioinformatics and Structural Biology, National Tsing Hua University, Taiwan
| | - Tzu-Hao Wang
- Genomic Medicine Research Core Laboratory, Chang Gung Memorial Hospital, Taoyuan, Taiwan.,Department of Obstetrics and Gynecology, Chang Gung Memorial Hospital and Chang Gung University, Taoyuan, Taiwan.,School of Traditional Chinese Medicine, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Hsin-Shih Wang
- Department of Obstetrics and Gynecology, Chang Gung Memorial Hospital and Chang Gung University, Taoyuan, Taiwan
| | - Chyong-Huey Lai
- Department of Obstetrics and Gynecology, Chang Gung Memorial Hospital and Chang Gung University, Taoyuan, Taiwan
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10
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Zaman K, Sawczak V, Zaidi A, Butler M, Bennett D, Getsy P, Zeinomar M, Greenberg Z, Forbes M, Rehman S, Jyothikumar V, DeRonde K, Sattar A, Smith L, Corey D, Straub A, Sun F, Palmer L, Periasamy A, Randell S, Kelley TJ, Lewis SJ, Gaston B. Augmentation of CFTR maturation by S-nitrosoglutathione reductase. Am J Physiol Lung Cell Mol Physiol 2015; 310:L263-70. [PMID: 26637637 DOI: 10.1152/ajplung.00269.2014] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Accepted: 11/20/2015] [Indexed: 12/27/2022] Open
Abstract
S-nitrosoglutathione (GSNO) reductase regulates novel endogenous S-nitrosothiol signaling pathways, and mice deficient in GSNO reductase are protected from airways hyperreactivity. S-nitrosothiols are present in the airway, and patients with cystic fibrosis (CF) tend to have low S-nitrosothiol levels that may be attributed to upregulation of GSNO reductase activity. The present study demonstrates that 1) GSNO reductase activity is increased in the cystic fibrosis bronchial epithelial (CFBE41o(-)) cells expressing mutant F508del-cystic fibrosis transmembrane regulator (CFTR) compared with the wild-type CFBE41o(-) cells, 2) GSNO reductase expression level is increased in the primary human bronchial epithelial cells expressing mutant F508del-CFTR compared with the wild-type cells, 3) GSNO reductase colocalizes with cochaperone Hsp70/Hsp90 organizing protein (Hop; Stip1) in human airway epithelial cells, 4) GSNO reductase knockdown with siRNA increases the expression and maturation of CFTR and decreases Stip1 expression in human airway epithelial cells, 5) increased levels of GSNO reductase cause a decrease in maturation of CFTR, and 6) a GSNO reductase inhibitor effectively reverses the effects of GSNO reductase on CFTR maturation. These studies provide a novel approach to define the subcellular location of the interactions between Stip1 and GSNO reductase and the role of S-nitrosothiols in these interactions.
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Affiliation(s)
- Khalequz Zaman
- Pediatric Pulmonology Division, Department of Pediatrics, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Victoria Sawczak
- Pediatric Pulmonology Division, Department of Pediatrics, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Atiya Zaidi
- Pediatric Pulmonology Division, Department of Pediatrics, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Maya Butler
- Pediatric Respiratory Medicine, Department of Pediatrics, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Deric Bennett
- Pediatric Respiratory Medicine, Department of Pediatrics, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Paulina Getsy
- Pediatric Pulmonology Division, Department of Pediatrics, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Maryam Zeinomar
- Pediatric Pulmonology Division, Department of Pediatrics, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Zivi Greenberg
- Pediatric Respiratory Medicine, Department of Pediatrics, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Michael Forbes
- Pediatric Respiratory Medicine, Department of Pediatrics, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Shagufta Rehman
- W. M. Keck Center for Cellular Imaging, Department of Biology, University of Virginia, Charlottesville, Virginiga
| | - Vinod Jyothikumar
- W. M. Keck Center for Cellular Imaging, Department of Biology, University of Virginia, Charlottesville, Virginiga
| | - Kim DeRonde
- Pediatric Respiratory Medicine, Department of Pediatrics, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Abdus Sattar
- Department of Epidemiology and Biostatistics, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Laura Smith
- Pediatric Pulmonology Division, Department of Pediatrics, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Deborah Corey
- Pediatric Pulmonology Division, Department of Pediatrics, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Adam Straub
- Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Fei Sun
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan
| | - Lisa Palmer
- Pediatric Respiratory Medicine, Department of Pediatrics, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Ammasi Periasamy
- W. M. Keck Center for Cellular Imaging, Department of Biology, University of Virginia, Charlottesville, Virginiga
| | - Scott Randell
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Thomas J Kelley
- Pediatric Pulmonology Division, Department of Pediatrics, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Stephen J Lewis
- Pediatric Pulmonology Division, Department of Pediatrics, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Benjamin Gaston
- Pediatric Pulmonology Division, Department of Pediatrics, Case Western Reserve University School of Medicine, Cleveland, Ohio; Pediatric Pulmonology Division, Rainbow Babies and Children's Hospital, Cleveland, Ohio
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11
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Hsp90 regulates the dynamics of its cochaperone Sti1 and the transfer of Hsp70 between modules. Nat Commun 2015; 6:6655. [PMID: 25851214 PMCID: PMC4403447 DOI: 10.1038/ncomms7655] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Accepted: 02/17/2015] [Indexed: 12/24/2022] Open
Abstract
The cochaperone Sti1/Hop physically links Hsp70 and Hsp90. The protein exhibits one binding site for Hsp90 (TPR2A) and two binding sites for Hsp70 (TPR1 and TPR2B). How these sites are used remained enigmatic. Here we show that Sti1 is a dynamic, elongated protein that consists of a flexible N-terminal module, a long linker and a rigid C-terminal module. Binding of Hsp90 and Hsp70 regulates the Sti1 conformation with Hsp90 binding determining with which site Hsp70 interacts. Without Hsp90, Sti1 is more compact and TPR2B is the high-affinity interaction site for Hsp70. In the presence of Hsp90, Hsp70 shifts its preference. The linker connecting the two modules is crucial for the interaction with Hsp70 and for client activation in vivo. Our results suggest that the interaction of Hsp70 with Sti1 is tightly regulated by Hsp90 to assure transfer of Hsp70 between the modules, as a prerequisite for the efficient client handover. The chaperones Hsp70 and Hsp90 are physically linked via the cochaperone Sti1/Hop, that has two binding sites for Hsp70. Here, Röhl et al. show that binding of Hsp90 changes the conformation of Sti1/Hop and determines to which site Hsp70 binds, perhaps facilitating transfer of client proteins from Hsp70 to Hsp90.
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12
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Abstract
Insect heat shock proteins include ATP-independent small heat shock proteins and the larger ATP-dependent proteins, Hsp70, Hsp90, and Hsp60. In concert with cochaperones and accessory proteins, heat shock proteins mediate essential activities such as protein folding, localization, and degradation. Heat shock proteins are synthesized constitutively in insects and induced by stressors such as heat, cold, crowding, and anoxia. Synthesis depends on the physiological state of the insect, but the common function of heat shock proteins, often working in networks, is to maintain cell homeostasis through interaction with substrate proteins. Stress-induced expression of heat shock protein genes occurs in a background of protein synthesis inhibition, but in the course of diapause, a state of dormancy and increased stress tolerance, these genes undergo differential regulation without the general disruption of protein production. During diapause, when ATP concentrations are low, heat shock proteins may sequester rather than fold proteins.
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Affiliation(s)
- Allison M King
- Department of Biology, Dalhousie University, Halifax, NS, B3H 4R2, Canada; ,
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13
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Baindur-Hudson S, Edkins AL, Blatch GL. Hsp70/Hsp90 organising protein (hop): beyond interactions with chaperones and prion proteins. Subcell Biochem 2015; 78:69-90. [PMID: 25487016 DOI: 10.1007/978-3-319-11731-7_3] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The Hsp70/Hsp90 organising protein (Hop), also known as stress-inducible protein 1 (STI1), has received considerable attention for diverse cellular functions in both healthy and diseased states. There is extensive evidence that intracellular Hop is a co-chaperone of the major chaperones Hsp70 and Hsp90, playing an important role in the productive folding of Hsp90 client proteins. Consequently, Hop is implicated in a number of key signalling pathways, including aberrant pathways leading to cancer. However, Hop is also secreted and it is now well established that Hop also serves as a receptor for the prion protein, PrP(C). The intracellular and extracellular forms of Hop most likely represent two different isoforms, although the molecular determinants of these divergent functions are yet to be identified. There is also a growing body of research that reports the involvement of Hop in cellular activities that appear independent of either chaperones or PrP(C). While Hop has been shown to have various cellular functions, its biological function remains elusive. However, recent knockout studies in mammals suggest that Hop has an important role in embryonic development. This review provides a critical overview of the latest molecular, cellular and biological research on Hop, critically evaluating its function in healthy systems and how this function is adapted in diseases states.
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Affiliation(s)
- Swati Baindur-Hudson
- College of Health and Biomedicine, Victoria University, VIC 8001, Melbourne, Australia,
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14
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Röhl A, Tippel F, Bender E, Schmid AB, Richter K, Madl T, Buchner J. Hop/Sti1 phosphorylation inhibits its co-chaperone function. EMBO Rep 2014; 16:240-9. [PMID: 25504578 PMCID: PMC4328751 DOI: 10.15252/embr.201439198] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
In eukaryotes, the molecular chaperones Hsp90 and Hsp70 are connected via the co-chaperone Sti1/Hop, which allows transfer of clients. Here, we show that the basic functions of yeast Sti1 and human Hop are conserved. These include the simultaneous binding of Hsp90 and Hsp70, the inhibition of the ATPase activity of Hsp90, and the ability to support client activation in vivo. Importantly, we reveal that both Hop and Sti1 are subject to inhibitory phosphorylation, although the sites modified and the influence of regulatory phosphorylation is species specific. Phospho-mimetic variants have a reduced ability to activate clients in vivo and different affinity for Hsp70. Hop is more tightly regulated, as phosphorylation affects also the interaction with Hsp90 and induces structural rearrangements in the core part of the protein.
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Affiliation(s)
- Alina Röhl
- Center for Integrated Protein Science (CIPSM) at the Department Chemie, Technische Universität München, Garching, Germany
| | - Franziska Tippel
- Center for Integrated Protein Science (CIPSM) at the Department Chemie, Technische Universität München, Garching, Germany
| | - Evelyn Bender
- Center for Integrated Protein Science (CIPSM) at the Department Chemie, Technische Universität München, Garching, Germany
| | - Andreas B Schmid
- Center for Integrated Protein Science (CIPSM) at the Department Chemie, Technische Universität München, Garching, Germany
| | - Klaus Richter
- Center for Integrated Protein Science (CIPSM) at the Department Chemie, Technische Universität München, Garching, Germany
| | - Tobias Madl
- Center for Integrated Protein Science (CIPSM) at the Department Chemie, Technische Universität München, Garching, Germany Institute of Structural Biology Helmholtz Zentrum München, Neuherberg, Germany Institute of Molecular Biology & Biochemistry, Center of Molecular Medicine, Medical University of Graz, Graz, Austria
| | - Johannes Buchner
- Center for Integrated Protein Science (CIPSM) at the Department Chemie, Technische Universität München, Garching, Germany
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15
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Hatherley R, Clitheroe CL, Faya N, Tastan Bishop Ö. Plasmodium falciparum Hop: detailed analysis on complex formation with Hsp70 and Hsp90. Biochem Biophys Res Commun 2014; 456:440-5. [PMID: 25482441 DOI: 10.1016/j.bbrc.2014.11.103] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2014] [Accepted: 11/25/2014] [Indexed: 12/29/2022]
Abstract
The heat shock organizing protein (Hop) is important in modulating the activity and co-interaction of two chaperones: heat shock protein 70 and 90 (Hsp70 and Hsp90). Recent research suggested that Plasmodium falciparum Hop (PfHop), PfHsp70 and PfHsp90 form a complex in the trophozoite infective stage. However, there has been little computational research on the malarial Hop protein in complex with other malarial Hsps. Using in silico characterization of the protein, this work showed that individual domains of Hop are evolving at different rates within the protein. Differences between human Hop (HsHop) and PfHop were identified by motif analysis. Homology modeling of PfHop and HsHop in complex with their own cytosolic Hsp90 and Hsp70 C-terminal peptide partners indicated excellent conservation of the Hop concave TPR sites bound to the C-terminal motifs of partner proteins. Further, we analyzed additional binding sites between Hop and Hsp90, and showed, for the first time, that they are distinctly less conserved between human and malaria parasite. These sites are located on the convex surface of Hop TPR2, and involved in interactions with the Hsp90 middle domain. Since the convex sites are less conserved than the concave sites, it makes their potential for malarial inhibitor design extremely attractive (as opposed to the concave sites which have been the focus of previous efforts).
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Affiliation(s)
- Rowan Hatherley
- Research Unit in Bioinformatics (RUBi), Department of Biochemistry and Microbiology, Rhodes University, 6140 Grahamstown, South Africa
| | - Crystal-Leigh Clitheroe
- Research Unit in Bioinformatics (RUBi), Department of Biochemistry and Microbiology, Rhodes University, 6140 Grahamstown, South Africa
| | - Ngonidzashe Faya
- Research Unit in Bioinformatics (RUBi), Department of Biochemistry and Microbiology, Rhodes University, 6140 Grahamstown, South Africa
| | - Özlem Tastan Bishop
- Research Unit in Bioinformatics (RUBi), Department of Biochemistry and Microbiology, Rhodes University, 6140 Grahamstown, South Africa.
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Yamamoto S, Subedi GP, Hanashima S, Satoh T, Otaka M, Wakui H, Sawada KI, Yokota SI, Yamaguchi Y, Kubota H, Itoh H. ATPase activity and ATP-dependent conformational change in the co-chaperone HSP70/HSP90-organizing protein (HOP). J Biol Chem 2014; 289:9880-6. [PMID: 24535459 PMCID: PMC3975032 DOI: 10.1074/jbc.m114.553255] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Co-chaperones help to maintain cellular homeostasis by modulating the activities of molecular chaperones involved in protein quality control. The HSP70/HSP90-organizing protein (HOP) is a co-chaperone that cooperates with HSP70 and HSP90 in catalysis of protein folding and maturation in the cytosol. We show here that HOP has ATP-binding activity comparable to that of HSP70/HSP90, and that HOP slowly hydrolyzes ATP. Analysis of deletion mutants revealed that the ATPase domain of HOP is in the N-terminal TPR1-DP1-TPR2A segment. In addition, HOP changes its conformation in the presence of ATP. These results indicate that HOP is a unique co-chaperone that undergoes an ATP-dependent conformational change.
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Affiliation(s)
- Soh Yamamoto
- From the Department of Life Science, Faculty and Graduate School of Engineering and Resource Science, Akita University, Akita 010-8502, Japan
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17
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Li HB, Du YZ. Molecular cloning and characterization of an Hsp90/70 organizing protein gene from Frankliniella occidentalis (Insecta: Thysanoptera, Thripidae). Gene 2013; 520:148-55. [DOI: 10.1016/j.gene.2013.02.026] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Revised: 02/06/2013] [Accepted: 02/13/2013] [Indexed: 01/06/2023]
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18
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Gitau GW, Mandal P, Blatch GL, Przyborski J, Shonhai A. Characterisation of the Plasmodium falciparum Hsp70-Hsp90 organising protein (PfHop). Cell Stress Chaperones 2012; 17:191-202. [PMID: 22005844 PMCID: PMC3273567 DOI: 10.1007/s12192-011-0299-x] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Revised: 10/03/2011] [Accepted: 10/04/2011] [Indexed: 10/25/2022] Open
Abstract
Malaria is caused by Plasmodium species, whose transmission to vertebrate hosts is facilitated by mosquito vectors. The transition from the cold blooded mosquito vector to the host represents physiological stress to the parasite, and additionally malaria blood stage infection is characterised by intense fever periods. In recent years, it has become clear that heat shock proteins play an essential role during the parasite's life cycle. Plasmodium falciparum expresses two prominent heat shock proteins: heat shock protein 70 (PfHsp70) and heat shock protein 90 (PfHsp90). Both of these proteins have been implicated in the development and pathogenesis of malaria. In eukaryotes, Hsp70 and Hsp90 proteins are functionally linked by an essential adaptor protein known as the Hsp70-Hsp90 organising protein (Hop). In this study, recombinant P. falciparum Hop (PfHop) was heterologously produced in E. coli and purified by nickel affinity chromatography. Using specific anti-PfHop antisera, the expression and localisation of PfHop in P. falciparum was investigated. PfHop was shown to co-localise with PfHsp70 and PfHsp90 in parasites at the trophozoite stage. Gel filtration and co-immunoprecipitation experiments suggested that PfHop was present in a complex together with PfHsp70 and PfHsp90. The association of PfHop with both PfHsp70 and PfHsp90 suggests that this protein may mediate the functional interaction between the two chaperones.
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Affiliation(s)
- Grace W. Gitau
- Department of Biochemistry and Microbiology, Zululand University, Kwadlangezwa, South Africa
| | - Pradipta Mandal
- FB Biology, Philipps University Marburg, 35043 Marburg, Germany
| | - Gregory L. Blatch
- Biomedical Biotechnology Research Unit, Department of Biochemistry, Microbiology and Biotechnology, Rhodes University, Grahamstown, 6140 South Africa
- School of Biomedical and Health Sciences, Victoria University, Melbourne, Victoria 8001 Australia
| | - Jude Przyborski
- FB Biology, Philipps University Marburg, 35043 Marburg, Germany
| | - Addmore Shonhai
- Department of Biochemistry and Microbiology, Zululand University, Kwadlangezwa, South Africa
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19
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Faou P, Hoogenraad NJ. Tom34: A cytosolic cochaperone of the Hsp90/Hsp70 protein complex involved in mitochondrial protein import. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2012; 1823:348-57. [DOI: 10.1016/j.bbamcr.2011.12.001] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2011] [Revised: 11/17/2011] [Accepted: 12/02/2011] [Indexed: 10/14/2022]
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20
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The architecture of functional modules in the Hsp90 co-chaperone Sti1/Hop. EMBO J 2012; 31:1506-17. [PMID: 22227520 DOI: 10.1038/emboj.2011.472] [Citation(s) in RCA: 170] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2011] [Accepted: 11/30/2011] [Indexed: 01/11/2023] Open
Abstract
Sti1/Hop is a modular protein required for the transfer of client proteins from the Hsp70 to the Hsp90 chaperone system in eukaryotes. It binds Hsp70 and Hsp90 simultaneously via TPR (tetratricopeptide repeat) domains. Sti1/Hop contains three TPR domains (TPR1, TPR2A and TPR2B) and two domains of unknown structure (DP1 and DP2). We show that TPR2A is the high affinity Hsp90-binding site and TPR1 and TPR2B bind Hsp70 with moderate affinity. The DP domains exhibit highly homologous α-helical folds as determined by NMR. These, and especially DP2, are important for client activation in vivo. The core module of Sti1 for Hsp90 inhibition is the TPR2A-TPR2B segment. In the crystal structure, the two TPR domains are connected via a rigid linker orienting their peptide-binding sites in opposite directions and allowing the simultaneous binding of TPR2A to the Hsp90 C-terminal domain and of TPR2B to Hsp70. Both domains also interact with the Hsp90 middle domain. The accessory TPR1-DP1 module may serve as an Hsp70-client delivery system for the TPR2A-TPR2B-DP2 segment, which is required for client activation in vivo.
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21
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Hsp90 in non-mammalian metazoan model systems. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2011; 1823:712-21. [PMID: 21983200 DOI: 10.1016/j.bbamcr.2011.09.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2011] [Revised: 09/08/2011] [Accepted: 09/09/2011] [Indexed: 01/26/2023]
Abstract
The molecular chaperone Hsp90 has been discovered in the heat-shock response of the fruit fly more than 30years ago. Today, it is becoming clear that Hsp90 is in the middle of a regulatory system, participating in the modulation of many essential client proteins and signaling pathways. Exerting these activities, Hsp90 works together with about a dozen of cochaperones. Due to their organismal simplicity and the possibility to influence their genetics on a large scale, many studies have addressed the function of Hsp90 in several multicellular model systems. Defined pathways involving Hsp90 client proteins have been identified in the metazoan model systems of Caenorhabditis elegans, Drosophila melanogaster and the zebrafish Danio rerio. Here, we summarize the functions of Hsp90 during muscle maintenance, development of phenotypic traits and the involvement of Hsp90 in stress responses, all of which were largely uncovered using the model organisms covered in this review. These findings highlight the many specific and general actions of the Hsp90 chaperone machinery. This article is part of a Special Issue entitled: Heat Shock Protein 90 (HSP90).
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22
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Place SP. Single-point mutation in a conserved TPR domain of Hip disrupts enhancement of glucocorticoid receptor signaling. Cell Stress Chaperones 2011; 16:469-74. [PMID: 21240662 PMCID: PMC3118830 DOI: 10.1007/s12192-010-0254-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2010] [Revised: 12/22/2010] [Accepted: 12/23/2010] [Indexed: 10/18/2022] Open
Abstract
The Hsp70-interacting protein Hip has been identified as a transient participant in the assembly of both glucocorticoid (GR) and progesterone receptor complexes. Although it has been difficult to identify a physiological role for Hip, it is believed to have intrinsic chaperoning properties and has been identified as a potential anti-apoptotic target of Granzyme B. In vitro assays have provided evidence that Hip may interact with GR complexes in an Hsp70 independent manner and can enhance the function of GR in hormone based reporter assays. In this study, a cDNA for human Hip was used in mutational analysis to map Hip function to critical structural elements. A single amino acid substitution (L211S) resulted in a loss of Hip function. This mutation also appears to disrupt the interaction of Hip with Hsp70 in vitro. Failure to recover Hip-L211S constructs in co-immunoprecipitation assays with an Hsp70 monoclonal antibody suggests that the mutation is unlikely to result in a misfolded substrate.
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Affiliation(s)
- Sean P Place
- Department of Biological Sciences, University of South Carolina, Columbia, USA.
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23
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Cox MB, Johnson JL. The role of p23, Hop, immunophilins, and other co-chaperones in regulating Hsp90 function. Methods Mol Biol 2011; 787:45-66. [PMID: 21898226 DOI: 10.1007/978-1-61779-295-3_4] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Molecular chaperones are a diverse group of highly conserved proteins that transiently interact with partially folded polypeptide chains during normal cellular processes, such as protein translation, translocation, and disassembly of protein complexes (1). Prior to folding or after denaturation, hydrophobic residues that are normally sequestered within a folded protein are exposed to the aqueous environment and are prone to aggregation or misfolding. Multiple classes of molecular chaperones, such as Hsp70s and Hsp40s, recognize and transiently bind polypeptides with exposed hydrophobic stretches in order to prevent misfolding. Other types of chaperones, such as Hsp90, have more specialized functions in that they appear to interact with only a subset of cellular proteins. This chapter focuses on the role of Hsp90 and partner co-chaperones in promoting the folding and activation of a diverse group of proteins with critical roles in cellular signaling and function.
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Affiliation(s)
- Marc B Cox
- Department of Biological Sciences, University of Texas at El Paso, El Paso, TX, USA
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24
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Gangaraju VK, Yin H, Weiner MM, Wang J, Huang XA, Lin H. Drosophila Piwi functions in Hsp90-mediated suppression of phenotypic variation. Nat Genet 2010; 43:153-8. [PMID: 21186352 PMCID: PMC3443399 DOI: 10.1038/ng.743] [Citation(s) in RCA: 136] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2010] [Accepted: 11/22/2010] [Indexed: 01/01/2023]
Affiliation(s)
- Vamsi K Gangaraju
- Yale Stem Cell Center and Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut, USA
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25
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Kubota H, Yamamoto S, Itoh E, Abe Y, Nakamura A, Izumi Y, Okada H, Iida M, Nanjo H, Itoh H, Yamamoto Y. Increased expression of co-chaperone HOP with HSP90 and HSC70 and complex formation in human colonic carcinoma. Cell Stress Chaperones 2010; 15:1003-11. [PMID: 20617406 PMCID: PMC3024075 DOI: 10.1007/s12192-010-0211-0] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2010] [Accepted: 06/18/2010] [Indexed: 01/25/2023] Open
Abstract
Co-chaperone HOP (also called stress-inducible protein 1) is a co-chaperone that interacts with the cytosolic 70-kDa heat shock protein (HSP70) and 90-kDa heat shock protein (HSP90) families using different tetratricopeptide repeat domains. HOP plays crucial roles in the productive folding of substrate proteins by controlling the chaperone activities of HSP70 and HSP90. Here, we examined the levels of HOP, HSC70 (cognate of HSP70, also called HSP73), and HSP90 in the tumor tissues from colon cancer patients, in comparison with the non-tumor tissues from the same patients. Expression level of HOP was significantly increased in the tumor tissues (68% of patients, n = 19). Levels of HSC70 and HSP90 were also increased in the tumor tissues (95% and 74% of patients, respectively), and the HOP level was highly correlated with those of HSP90 (r = 0.77, p < 0.001) and HSC70 (r = 0.68, p < 0.01). Immunoprecipitation experiments indicated that HOP complexes with HSC70 or HSP90 in the tumor tissues. These data are consistent with increased formation of co-chaperone complexes in colon tumor specimens compared to adjacent normal tissue and could reflect a role for HOP in this process.
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Affiliation(s)
- Hiroshi Kubota
- Department of Life Science, Faculty and Graduate School of Engineering and Resource Science, Akita University, 1-1 Tegata-Gakuencho, Akita, 010-8502 Japan
| | - Soh Yamamoto
- Department of Life Science, Faculty and Graduate School of Engineering and Resource Science, Akita University, 1-1 Tegata-Gakuencho, Akita, 010-8502 Japan
| | - Eri Itoh
- Department of Life Science, Faculty and Graduate School of Engineering and Resource Science, Akita University, 1-1 Tegata-Gakuencho, Akita, 010-8502 Japan
| | - Yuki Abe
- Department of Gastroenterological Surgery, Akita University Graduate School of Medicine, Akita, 010-8543 Japan
| | - Asami Nakamura
- Department of Life Science, Faculty and Graduate School of Engineering and Resource Science, Akita University, 1-1 Tegata-Gakuencho, Akita, 010-8502 Japan
| | - Yukina Izumi
- Department of Life Science, Faculty and Graduate School of Engineering and Resource Science, Akita University, 1-1 Tegata-Gakuencho, Akita, 010-8502 Japan
| | - Hirotaka Okada
- Department of Life Science, Faculty and Graduate School of Engineering and Resource Science, Akita University, 1-1 Tegata-Gakuencho, Akita, 010-8502 Japan
| | - Masatake Iida
- Department of Gastroenterological Surgery, Akita University Graduate School of Medicine, Akita, 010-8543 Japan
| | - Hiroshi Nanjo
- Department of Pathology, Akita University Hospital, Akita, 010-8543 Japan
| | - Hideaki Itoh
- Department of Life Science, Faculty and Graduate School of Engineering and Resource Science, Akita University, 1-1 Tegata-Gakuencho, Akita, 010-8502 Japan
| | - Yuzo Yamamoto
- Department of Gastroenterological Surgery, Akita University Graduate School of Medicine, Akita, 010-8543 Japan
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26
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van de Hoef DL, Hughes J, Livne-Bar I, Garza D, Konsolaki M, Boulianne GL. Identifying genes that interact with Drosophila presenilin and amyloid precursor protein. Genesis 2009; 47:246-60. [PMID: 19241393 DOI: 10.1002/dvg.20485] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The gamma-secretase complex is involved in cleaving transmembrane proteins such as Notch and one of the genes targeted in Alzheimer's disease known as amyloid precursor protein (APP). Presenilins function within the catalytic core of gamma-secretase, and mutated forms of presenilins were identified as causative factors in familial Alzheimer's disease. Recent studies show that in addition to Notch and APP, numerous signal transduction pathways are modulated by presenilins, including intracellular calcium signaling. Thus, presenilins appear to have diverse roles. To further understand presenilin function, we searched for Presenilin-interacting genes in Drosophila by performing a genetic modifier screen for enhancers and suppressors of Presenilin-dependent Notch-related phenotypes. We identified 177 modifiers, including known members of the Notch pathway and genes involved in intracellular calcium homeostasis. We further demonstrate that 53 of these modifiers genetically interacted with APP. Characterization of these genes may provide valuable insights into Presenilin function in development and disease.
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Affiliation(s)
- Diana L van de Hoef
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
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27
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Li JY, Chen X, Fan W, Moghaddam SHH, Chen M, Zhou ZH, Yang HJ, Chen JE, Zhong BX. Proteomic and bioinformatic analysis on endocrine organs of domesticated silkworm, Bombyx mori L. for a comprehensive understanding of their roles and relations. J Proteome Res 2009; 8:2620-32. [PMID: 19382758 DOI: 10.1021/pr8006123] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Three organs of silkworm larva endocrine system, including brain (Br), subesophageal ganglion (SG) and prothoracic glands (PG), were studied employing shotgun LC-MS/MS combined with bioinformatic analysis to comprehensively understand their roles and relations. Totally, 3430, 2683, and 3395 proteins were identified including 1885 common and 652, 253, and 790 organ-specific ones in Br, SG, and PG, respectively. Identified common-expressed proteins indicated the existence of intrinsic complex interactions among these parts of endocrine system. Most of the reputed organs-specific proteins were identified by this approach. KEGG pathway analysis showed 162 same pathways among the 169, 164, and 171 relating Br, SG, and PG. This analysis revealed functional similarities with exceptional resemblance in their metabolism and signaling pathways of the three organs. On the other hand, 70, 57, and 114 organ-specific enzymes related pathways were detected for Br, SG, and PG confirming their functional differences. These results reveal a cooperative mechanism among the three endocrine organs in regulating various physiological and developmental events, and also suggest that the organ-specific proteins might be the fundamental factors responsible for the functional differentiation of these organs.
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Affiliation(s)
- Jian-Ying Li
- College of Animal Sciences, Zhejiang University, Hangzhou 310029, P. R. China
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28
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Gaiser AM, Brandt F, Richter K. The Non-canonical Hop Protein from Caenorhabditis elegans Exerts Essential Functions and Forms Binary Complexes with Either Hsc70 or Hsp90. J Mol Biol 2009; 391:621-34. [DOI: 10.1016/j.jmb.2009.06.051] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2009] [Revised: 05/28/2009] [Accepted: 06/18/2009] [Indexed: 10/20/2022]
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29
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Cheng L, Jin Z, Fu C, Zhao D. Cloning and expression analysis of a hsp70 gene fromSaussurea medusa. ACTA ACUST UNITED AC 2009; 17:159-65. [PMID: 17076259 DOI: 10.1080/10425170600609256] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Members of the 70 kD heat-shock gene family are highly conserved across a wide range of organisms. In an effort to learn more about the evolution and possible functions of extreme environment plant Saussurea medusa Maxim hsp70, we isolated a cDNA clone encoding a putative cytosolic member (Smhsp70) of this family of proteins from a cDNA library of S. medusa cell cultures. The cDNA clone was 2224 bp in length and contained a 1941 bp open reading frame (ORF) encoding a polypeptide of 647 amino acid residues with a predicted molecular mass of 70,794 Da. The predicted protein was found to contain a C-terminal amino acid motif of "PKIEEVD" indicating that Smhsp70 was related to cytosolic members of the hsp70 family in higher plant. The secondary and three-dimensional structures of Smhsp70 were analyzed by molecular modeling. The genomic structure of Smhsp70 included one intron of 1134 bp in length. The deduced Smhsp70 protein has 93.7 and 93.2% similarity with the hsp70 of tobacco and tomato, 73.2% with the hsp70 of human, and 43.7% with DnaK of Escherichia. coli, respectively. Semiquantitative reverse transcription-polymerase chain reaction (RT-PCR) analyses indicated that the cytosolic Smhsp70 protein was constitutively expressed and markedly increased after relatively short periods of heat shock (37 degrees C) as well as by low temperature (4 degree C) treatments.
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Affiliation(s)
- Liqin Cheng
- Key Laboratory of Photosynthesis and Environmental Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Nanxinchun20, Xiangshan, Haidian District, Beijing, People's Republic of China
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30
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Hernández Torres J, Papandreou N, Chomilier J. Sequence analyses reveal that a TPR-DP module, surrounded by recombinable flanking introns, could be at the origin of eukaryotic Hop and Hip TPR-DP domains and prokaryotic GerD proteins. Cell Stress Chaperones 2009; 14:281-9. [PMID: 18987995 PMCID: PMC2728264 DOI: 10.1007/s12192-008-0083-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2008] [Accepted: 09/15/2008] [Indexed: 11/27/2022] Open
Abstract
The co-chaperone Hop [heat shock protein (HSP) organising protein] is known to bind both Hsp70 and Hsp90. Hop comprises three repeats of a tetratricopeptide repeat (TPR) domain, each consisting of three TPR motifs. The first and last TPR domains are followed by a domain containing several dipeptide (DP) repeats called the DP domain. These analyses suggest that the hop genes result from successive recombination events of an ancestral TPR-DP module. From a hydrophobic cluster analysis of homologous Hop protein sequences derived from gene families, we can postulate that shifts in the open reading frames are at the origin of the present sequences. Moreover, these shifts can be related to the presence or absence of biological function. We propose to extend the family of Hop co-chaperons into the kingdom of bacteria, as several structurally related genes have been identified by hydrophobic cluster analysis. We also provide evidence of common structural characteristics between hop and hip genes, suggesting a shared precursor of ancestral TPR-DP domains.
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Affiliation(s)
- Jorge Hernández Torres
- Laboratorio de Biología Molecular, Escuela de Biología, Universidad Industrial de Santander, Apartado Aéreo 678, Bucaramanga, Colombia.
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31
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Yan X, Liu T, Yang S, Ding Q, Liu Y, Zhang X, Que H, Wei K, Luo Z, Liu S. Proteomic Profiling of the Insoluble Pellets of the Transected Rat Spinal Cord. J Neurotrauma 2009; 26:179-93. [DOI: 10.1089/neu.2008.0533] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Xiaodong Yan
- Department of Neurobiology, Institute of Basic Medical Sciences, State Key Laboratory of Proteomics, Beijing, P. R. China
- Department of Orthopaedic Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, P. R. China
| | - Tao Liu
- Department of Neurobiology, Institute of Basic Medical Sciences, State Key Laboratory of Proteomics, Beijing, P. R. China
| | - Shuguang Yang
- Department of Neurobiology, Institute of Basic Medical Sciences, State Key Laboratory of Proteomics, Beijing, P. R. China
| | - Qinxue Ding
- Department of Neurobiology, Institute of Basic Medical Sciences, State Key Laboratory of Proteomics, Beijing, P. R. China
| | - Yong Liu
- Department of Neurobiology, Institute of Basic Medical Sciences, State Key Laboratory of Proteomics, Beijing, P. R. China
| | - Xiaojun Zhang
- Department of Neurobiology, Institute of Basic Medical Sciences, State Key Laboratory of Proteomics, Beijing, P. R. China
| | - Haiping Que
- Department of Neurobiology, Institute of Basic Medical Sciences, State Key Laboratory of Proteomics, Beijing, P. R. China
| | - Kaihua Wei
- National Center of Biomedical Analysis, Beijing, P. R. China
| | - Zhuojing Luo
- Department of Orthopaedic Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, P. R. China
| | - Shaojun Liu
- Department of Neurobiology, Institute of Basic Medical Sciences, State Key Laboratory of Proteomics, Beijing, P. R. China
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32
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Johnson JL, Brown C. Plasticity of the Hsp90 chaperone machine in divergent eukaryotic organisms. Cell Stress Chaperones 2009; 14:83-94. [PMID: 18636345 PMCID: PMC2673905 DOI: 10.1007/s12192-008-0058-9] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2008] [Revised: 06/10/2008] [Accepted: 06/12/2008] [Indexed: 12/29/2022] Open
Abstract
Hsp90 is critical for the regulation and activation of numerous client proteins critical for diverse functions such as cell growth, differentiation, and reproduction. Cytosolic Hsp90 function is dependent on a battery of co-chaperone proteins that regulate the ATPase activity of Hsp90 function or direct Hsp90 to interact with specific client proteins. Little is known about how Hsp90 complexes vary between different organisms and how this affects the scope of clients that are activated by Hsp90. This study determined whether ten distinct Hsp90 co-chaperones were encoded by genes in 19 disparate eukaryotic organisms. Surprisingly, none of the co-chaperones were present in all organisms. The co-chaperone Hop/Sti1 was most widely dispersed (18 out of 19 species), while orthologs of Cdc37, which is critical for the stability and activation of diverse protein kinases in yeast and mammals, were identified in only nine out of 19 species examined. The organism with the smallest proteome, Encephalitozoon cuniculi, contained only three of these co-chaperones, suggesting a correlation between client diversity and the complexity of the Hsp90 co-chaperone machine. Our results suggest co-chaperones are critical for cytosolic Hsp90 function in vivo, but that the composition of Hsp90 complexes varies depending on the specialized protein folding requirements of divergent species.
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Affiliation(s)
- Jill L Johnson
- Department of Microbiology, Molecular Biology and Biochemistry and the Center for Reproductive Biology, Moscow, ID 83844-3052, USA.
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33
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Ishida R, Takaoka Y, Yamamoto S, Miyazaki T, Otaka M, Watanabe S, Komatsuda A, Wakui H, Sawada KI, Kubota H, Itoh H. Cisplatin differently affects amino terminal and carboxyl terminal domains of HSP90. FEBS Lett 2008; 582:3879-83. [PMID: 18955054 DOI: 10.1016/j.febslet.2008.10.029] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2008] [Revised: 10/13/2008] [Accepted: 10/14/2008] [Indexed: 01/08/2023]
Abstract
The 90-kDa heat shock protein (HSP90) is a molecular chaperone that assists in the folding and assembly of proteins in the cytosol. We previously demonstrated that the antineoplastic reagent, cisplatin, inhibits the aggregation prevention activity of mammalian HSP90. We now show that cisplatin binds both the amino terminal and carboxyl terminal domains of the human HSP90 and differently affects these two domains. Cisplatin blocks the aggregation prevention activity of HSP90C, but not HSP90N. In contrast, cisplatin induces a conformational change in HSP90N, but not HSP90C. These results indicate that cisplatin modulates the HSP90 activities through two different mechanisms using the two distinct binding sites of the HSP90 molecule.
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Affiliation(s)
- Ryuichi Ishida
- Department of Life Science, Faculty of Engineering and Resource Science, Akita University, 1-1 Tegata Gakuen Town, Akita 010-8502, Japan
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34
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Rousselet E, Martelli A, Chevallet M, Diemer H, Van Dorsselaer A, Rabilloud T, Moulis JM. Zinc adaptation and resistance to cadmium toxicity in mammalian cells: molecular insight by proteomic analysis. Proteomics 2008; 8:2244-55. [PMID: 18452231 DOI: 10.1002/pmic.200701067] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
To identify proteins involved in cellular adaptive responses to zinc, a comparative proteome analysis between a previously developed high zinc- and cadmium-resistant human epithelial cell line (high zinc-resistant HeLa cells, HZR) and the parental HeLa cells has been carried out. Differentially produced proteins included cochaperones, proteins associated with oxido-reductase activities, and ubiquitin. Biochemical pathways to which these proteins belong were probed for their involvement in the resistance of both cell lines against cadmium toxicity. Among ER stressors, thapsigargin sensitized HZR cells, but not HeLa cells, to cadmium toxicity more acutely than tunicamycin, implying that these cells heavily relied on proper intracellular calcium distribution. The similar sensitivity of both HeLa and HZR cells to inhibitors of the proteasome, such as MG-132 or lactacystin, excluded improved proteasome activity as a mechanism associated with zinc adaptation of HZR cells. The enzyme 4-hydroxyphenylpyruvate dioxygenase (HPPD) was overproduced in HZR cells as compared to HeLa cells. It transforms HPP to homogentisate in the second step of tyrosine catabolism. Inhibition of HPPD decreased the resistance of HZR cells against cadmium, but not that of HeLa cells, suggesting that adaptation to zinc overload and increased HPP removal are linked in HZR cells.
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Affiliation(s)
- Estelle Rousselet
- CEA, DSV, IRTSV, Laboratoire de Chimie et Biologie des Métaux, Grenoble, France
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Nuclear translocation of the phosphoprotein Hop (Hsp70/Hsp90 organizing protein) occurs under heat shock, and its proposed nuclear localization signal is involved in Hsp90 binding. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2008; 1783:1003-14. [PMID: 18280255 DOI: 10.1016/j.bbamcr.2008.01.014] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2007] [Revised: 01/11/2008] [Accepted: 01/14/2008] [Indexed: 11/24/2022]
Abstract
The Hsp70-Hsp90 complex is implicated in the folding and regulation of numerous signaling proteins, and Hop, the Hsp70-Hsp90 Organizing Protein, facilitates the association of this multichaperone machinery. Phosphatase treatment of mouse cell extracts reduced the number of Hop isoforms compared to untreated extracts, providing the first direct evidence that Hop was phosphorylated in vivo. Furthermore, surface plasmon resonance (SPR) spectroscopy showed that a cdc2 kinase phosphorylation mimic of Hop had reduced affinity for Hsp90 binding. Hop was predominantly cytoplasmic, but translocated to the nucleus in response to heat shock. A putative bipartite nuclear localization signal (NLS) has been identified within the Hsp90-binding domain of Hop. Although substitution of residues within the major arm of this proposed NLS abolished Hop-Hsp90 interaction as determined by SPR, this was not sufficient to prevent the nuclear accumulation of Hop under leptomycin-B treatment and heat shock conditions. These results showed for the first time that the subcellular localization of Hop was stress regulated and that the major arm of the putative NLS was not directly important for nuclear translocation but was critical for Hop-Hsp90 association in vitro. We propose a model in which the association of Hop with Hsp90 and the phosphorylated status of Hop both play a role in the mechanism of nucleo-cytoplasmic shuttling of Hop.
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36
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Ferrari G, Pastorelli R, Buchi F, Spinelli E, Gozzini A, Bosi A, Santini V. Comparative proteomic analysis of chronic myelogenous leukemia cells: inside the mechanism of imatinib resistance. J Proteome Res 2007; 6:367-75. [PMID: 17203980 DOI: 10.1021/pr0603708] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Imatinib is the first molecular targeted therapy that has shown clinical success, but imatinib acquired resistance, although a rare event, is critical during the therapy of chronic myelogenous leukaemia (CML). With the aim of better understanding the molecular mechanisms accompanying acquisition of resistance to this drug, a comparative proteomic approach was undertaken on CML cell lines LAMA 84 S (imatinib sensitive) and LAMA 84 R (imatinib resistant). Forty-four differentially expressed proteins were identified and categorized into five main functional classes: (I) heat shock proteins and chaperones; (II) nucleic acid interacting proteins (binding/synthesis/stability); (III) structural proteins, (IV) cell signaling, and (V) metabolic enzymes. Several heat shock proteins known to complex Bcr-Abl were overexpressed in imatinib resistant cells, showing a possible involvement of these proteins in the mechanism of resistance. HnRNPs also resulted in being up-regulated in imatinib resistant cells. These proteins have been shown to be strongly and directly related to Bcr-Abl activity. To our knowledge, this is the first direct proteomic comparison of imatinib sensitive/resistant CML cell lines.
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MESH Headings
- Antineoplastic Agents/therapeutic use
- Benzamides
- Cell Line, Tumor
- Drug Resistance, Neoplasm
- Electrophoresis, Gel, Two-Dimensional
- Gene Expression Regulation, Leukemic
- Humans
- Image Processing, Computer-Assisted
- Imatinib Mesylate
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/metabolism
- Models, Biological
- Piperazines/therapeutic use
- Proteomics/methods
- Pyrimidines/therapeutic use
- Signal Transduction
- Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
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Affiliation(s)
- Germano Ferrari
- University of Florence, AUO Careggi, Department of Hematology, Florence, Italy
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37
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Flom G, Behal R, Rosen L, Cole D, Johnson J. Definition of the minimal fragments of Sti1 required for dimerization, interaction with Hsp70 and Hsp90 and in vivo functions. Biochem J 2007; 404:159-67. [PMID: 17300223 PMCID: PMC1868838 DOI: 10.1042/bj20070084] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The molecular chaperone Hsp (heat-shock protein) 90 is critical for the activity of diverse cellular client proteins. In a current model, client proteins are transferred from Hsp70 to Hsp90 in a process mediated by the co-chaperone Sti1/Hop, which may simultaneously interact with Hsp70 and Hsp90 via separate TPR (tetratricopeptide repeat) domains, but the mechanism and in vivo importance of this function is unclear. In the present study, we used truncated forms of Sti1 to determine the minimal regions required for the Hsp70 and Hsp90 interaction, as well as Sti1 dimerization. We found that both TPR1 and TPR2B contribute to the Hsp70 interaction in vivo and that mutations in both TPR1 and TPR2B were required to disrupt the in vitro interaction of Sti1 with the C-terminus of the Hsp70 Ssa1. The TPR2A domain was required for the Hsp90 interaction in vivo, but the isolated TPR2A domain was not sufficient for the Hsp90 interaction unless combined with the TPR2B domain. However, isolated TPR2A was both necessary and sufficient for purified Sti1 to migrate as a dimer in solution. The DP2 domain, which is essential for in vivo function, was dispensable for the Hsp70 and Hsp90 interaction, as well as Sti1 dimerization. As evidence for the role of Sti1 in mediating the interaction between Hsp70 and Hsp90 in vivo, we identified Sti1 mutants that result in reduced recovery of Hsp70 in Hsp90 complexes. We also identified two Hsp90 mutants that exhibit a reduced Hsp70 interaction, which may help clarify the mechanism of client transfer between the two molecular chaperones.
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Affiliation(s)
- Gary Flom
- Department of Microbiology, Molecular Biology and Biochemistry, and the Center for Reproductive Biology, University of Idaho, Moscow, ID 83844-3052, U.S.A
| | - Robert H. Behal
- Department of Microbiology, Molecular Biology and Biochemistry, and the Center for Reproductive Biology, University of Idaho, Moscow, ID 83844-3052, U.S.A
| | - Luke Rosen
- Department of Microbiology, Molecular Biology and Biochemistry, and the Center for Reproductive Biology, University of Idaho, Moscow, ID 83844-3052, U.S.A
| | - Douglas G. Cole
- Department of Microbiology, Molecular Biology and Biochemistry, and the Center for Reproductive Biology, University of Idaho, Moscow, ID 83844-3052, U.S.A
| | - Jill L. Johnson
- Department of Microbiology, Molecular Biology and Biochemistry, and the Center for Reproductive Biology, University of Idaho, Moscow, ID 83844-3052, U.S.A
- To whom correspondence should be addressed (email )
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38
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Abstract
Molecular chaperones are essential components of a quality control machinery present in the cell. They can either aid in the folding and maintenance of newly translated proteins, or they can lead to the degradation of misfolded and destabilized proteins. Hsp90 is a key member of this machinery. It is a ubiquitous molecular chaperone that is found in eubacteria and all branches of eukarya. It plays a central role in cellular signaling since it is essential for maintaining the activity of several signaling proteins, including steroid hormone receptors and protein kinases. Hsp90 is currently a novel anticancer drug target since it is overexpressed in some cancer cells. The chaperone typically functions as part of large complexes, which include other chaperones and essential cofactors that regulate its function. It is thought that different cofactors target Hsp90 to different sets of substrates. However, the mechanism of Hsp90 function remains poorly understood. As part of an effort to elucidate the Hsp90 chaperone network, we carried out a large-scale proteomics study to identify physical and genetic interactors of the chaperone. We identified 2 highly conserved novel Hsp90 cofactors, termed Tah1 and Pih1, that bind to the chaperone and that also associate physically and functionally with the essential DNA helicases Rvb1 and Rvb2. These helicases are key components of the chromatin remodeling complexes Ino80 and SWR-C. Tah1 and Pih1 seem to represent a novel class of Hsp90 cofactors that allow the chaperone to indirectly affect gene regulation in the cell in addition to its ability to directly promote protein folding. In this review, we provide an overview of Hsp90 structure and function, and we discuss the literature that links the chaperone activity to gene regulation.
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Affiliation(s)
- Rongmin Zhao
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada
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Carrigan PE, Sikkink LA, Smith DF, Ramirez-Alvarado M. Domain:domain interactions within Hop, the Hsp70/Hsp90 organizing protein, are required for protein stability and structure. Protein Sci 2006; 15:522-32. [PMID: 16452615 PMCID: PMC2249773 DOI: 10.1110/ps.051810106] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The major heat shock protein (Hsp) chaperones Hsp70 and Hsp90 both bind the co-chaperone Hop (Hsp70/Hsp90 organizing protein), which coordinates Hsp actions in folding protein substrates. Hop contains three tetratricopeptide repeat (TPR) domains that have binding sites for the conserved EEVD C termini of Hsp70 and Hsp90. Crystallographic studies have shown that EEVD interacts with positively charged amino acids in Hop TPR-binding pockets (called carboxylate clamps), and point mutations of these carboxylate clamp positions can disrupt Hsp binding. In this report, we use circular dichroism to assess the effects of point mutations and Hsp70/Hsp90 peptide binding on Hop conformation. Our results show that Hop global conformation is destabilized by single point mutations in carboxylate clamp positions at pH 5, while the structure of individual TPR domains is unaffected. Binding of peptides corresponding to the C termini of Hsp70 and Hsp90 alters the global conformation of wild-type Hop, whereas peptide binding does not alter conformation of individual TPR domains. These results provide biophysical evidence that Hop-binding pockets are directly involved with domain:domain interactions, both influencing Hop global conformation and Hsp binding, and contributing to proper coordination of Hsp70 and Hsp90 interactions with protein substrates.
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Affiliation(s)
- Patricia E Carrigan
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Scottsdale, AZ 85259, USA
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40
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Flom G, Weekes J, Williams JJ, Johnson JL. Effect of mutation of the tetratricopeptide repeat and asparatate-proline 2 domains of Sti1 on Hsp90 signaling and interaction in Saccharomyces cerevisiae. Genetics 2005; 172:41-51. [PMID: 16219779 PMCID: PMC1456168 DOI: 10.1534/genetics.105.045815] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Through simultaneous interactions with Hsp70 and Hsp90 via separate tetratricopeptide repeat (TPR) domains, the cochaperone protein Hop/Sti1 has been proposed to play a critical role in the transfer of client proteins from Hsp70 to Hsp90. However, no prior mutational analysis demonstrating a critical in vivo role for the TPR domains of Sti1 has been reported. We used site-directed mutagenesis of the TPR domains combined with a genetic screen to isolate mutations that disrupt Sti1 function. A single amino acid alteration in TPR2A disrupted Hsp90 interaction in vivo but did not significantly affect function. However, deletion of a conserved residue in TPR2A or mutations in the carboxy-terminal DP2 domain completely disrupted Sti1 function. Surprisingly, mutations in TPR1, previously shown to interact with Hsp70, were not sufficient to disrupt in vivo functions unless combined with mutations in TPR2B, suggesting that TPR1 and TPR2B have redundant or overlapping in vivo functions. We further examined the genetic and physical interaction of Sti1 with a mutant form of Hsp90, providing insight into the importance of the TPR2A domain of Sti1 in regulating Hsp90 function.
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Affiliation(s)
- Gary Flom
- Department of Microbiology, Molecular Biology and Biochemistry and the Center for Reproductive Biology, University of Idaho, Moscow, Idaho 83844-3052, USA
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41
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Song Y, Masison DC. Independent regulation of Hsp70 and Hsp90 chaperones by Hsp70/Hsp90-organizing protein Sti1 (Hop1). J Biol Chem 2005; 280:34178-85. [PMID: 16100115 PMCID: PMC1343460 DOI: 10.1074/jbc.m505420200] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Hsp70 and Hsp90 protein chaperones cooperate in a protein-folding pathway required by many "client" proteins. The co-chaperone Sti1p coordinates functions of Hsp70 and Hsp90 in this pathway. Sti1p has three tetratricopeptide repeat (TPR) domains. TPR1 binds Hsp70, TPR2a binds Hsp90, and the ligand for TPR2b is unknown. Although Sti1p is thought to be dedicated to the client folding pathway, we earlier showed that Sti1p regulated Hsp70, independently of Hsp90, in a way that impairs yeast [PSI+] prion propagation. Using this prion system to monitor Sti1p regulation of Hsp70 and an Hsp90-inhibiting compound to monitor Hsp90 regulation, we identified Sti1p mutations that separately affect Hsp70 and Hsp90. TPR1 mutations impaired Sti1p regulation of Hsp70, but deletion of TPR2a and TPR2b did not. Conversely, TPR2a and TPR2b mutations impaired Sti1p regulation of Hsp90, but deletion of TPR1 did not. All Sti1p mutations variously impaired the client folding pathway, which requires both Hsp70 and Hsp90. Thus, Sti1p regulated Hsp70 and Hsp90 separately, Hsp90 is implicated as a TPR2b ligand, and mutations separately affecting regulation of either chaperone impair a pathway that is dependent upon both. We further demonstrate that client folding depended upon bridging of Hsp70 and Hsp90 by Sti1p and find conservation of the independent regulation of Hsp70 and Hsp90 by human Hop1.
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Affiliation(s)
| | - Daniel C. Masison
- To whom correspondence should be addressed: Bldg. 8, Rm. 407, Laboratory of Biochemistry and Genetics, NIDDK, National Institutes of Health, 8 Center Dr., Bethesda, MD 20892-0851. Tel.: 301-594 -1316; Fax: 301-496-9631; E-mail:
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