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Harnagel A, Lopez Quezada L, Park SW, Baranowski C, Kieser K, Jiang X, Roberts J, Vaubourgeix J, Yang A, Nelson B, Fay A, Rubin E, Ehrt S, Nathan C, Lupoli TJ. Nonredundant functions of Mycobacterium tuberculosis chaperones promote survival under stress. Mol Microbiol 2020; 115:272-289. [PMID: 32996193 DOI: 10.1111/mmi.14615] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 09/21/2020] [Accepted: 09/22/2020] [Indexed: 12/12/2022]
Abstract
Bacterial chaperones ClpB and DnaK, homologs of the respective eukaryotic heat shock proteins Hsp104 and Hsp70, are essential in the reactivation of toxic protein aggregates that occur during translation or periods of stress. In the pathogen Mycobacterium tuberculosis (Mtb), the protective effect of chaperones extends to survival in the presence of host stresses, such as protein-damaging oxidants. However, we lack a full understanding of the interplay of Hsps and other stress response genes in mycobacteria. Here, we employ genome-wide transposon mutagenesis to identify the genes that support clpB function in Mtb. In addition to validating the role of ClpB in Mtb's response to oxidants, we show that HtpG, a homolog of Hsp90, plays a distinct role from ClpB in the proteotoxic stress response. While loss of neither clpB nor htpG is lethal to the cell, loss of both through genetic depletion or small molecule inhibition impairs recovery after exposure to host-like stresses, especially reactive nitrogen species. Moreover, defects in cells lacking clpB can be complemented by overexpression of other chaperones, demonstrating that Mtb's stress response network depends upon finely tuned chaperone expression levels. These results suggest that inhibition of multiple chaperones could work in concert with host immunity to disable Mtb.
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Affiliation(s)
- Alexa Harnagel
- Department of Chemistry, New York University, New York, NY, USA
| | - Landys Lopez Quezada
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
| | - Sae Woong Park
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
| | - Catherine Baranowski
- Department of Immunology and Infectious Disease, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Karen Kieser
- Department of Immunology and Infectious Disease, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Xiuju Jiang
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
| | - Julia Roberts
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
| | - Julien Vaubourgeix
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
| | - Amy Yang
- Department of Chemistry, New York University, New York, NY, USA
| | - Brock Nelson
- Department of Chemistry, New York University, New York, NY, USA
| | - Allison Fay
- Immunology Program, Sloan Kettering Institute, New York, NY, USA
| | - Eric Rubin
- Immunology Program, Sloan Kettering Institute, New York, NY, USA
| | - Sabine Ehrt
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
| | - Carl Nathan
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
| | - Tania J Lupoli
- Department of Chemistry, New York University, New York, NY, USA.,Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
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2
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Targeting hsp90 family members: A strategy to improve cancer cell death. Biochem Pharmacol 2019; 164:177-187. [PMID: 30981878 DOI: 10.1016/j.bcp.2019.04.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Accepted: 04/10/2019] [Indexed: 02/01/2023]
Abstract
A crucial process in biology is the conversion of the genetic information into functional proteins that carry out the genetic program. However, a supplementary step is required to obtain functional proteins: the folding of the newly translated polypeptides into well-defined, three-dimensional conformations. Proteins chaperones are crucial for this final step in the readout of genetic information, which results in the formation of functional proteins. In this review, a special attention will be given to the strategies targeting hsp90 family members in order to increase cancer cell death. We argue that disruption of hsp90 machinery and the further client protein degradation is the main consequence of hsp90 oxidative cleavage taking place at the N-terminal nucleotide-binding site. Moreover, modulation of Grp94 expression will be discussed as a potential therapeutic goal looking for a decrease in cancer relapses.
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3
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Structural insights into complexes of glucose-regulated Protein94 (Grp94) with human immunoglobulin G. relevance for Grp94-IgG complexes that form in vivo in pathological conditions. PLoS One 2014; 9:e86198. [PMID: 24489700 PMCID: PMC3904872 DOI: 10.1371/journal.pone.0086198] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Accepted: 12/04/2013] [Indexed: 01/17/2023] Open
Abstract
While the mechanism by which Grp94 displays its chaperone function with client peptides in the cell has been elucidated extensively, much less is known about the nature and properties of how Grp94 can engage binding to proteins once it is exposed on the cell surface or liberated in the extra-cellular milieu, as occurs in pathological conditions. In this work, we wanted to investigate the molecular aspects and structural characteristics of complexes that Grp94 forms with human IgG, posing the attention on the influence that glycosylation of Grp94 might have on the binding capacity to IgG, and on the identification of sites involved in the binding. To this aim, we employed both native, fully glycosylated and partially glycosylated Grp94, and recombinant, non-glycosylated Grp94, as well as IgG subunits, in different experimental conditions, including the physiological setting of human plasma. Regardless of the species and type, Grp94 engages a similar, highly specific and stable binding with IgG that involves sites located in the N-terminal domain of Grp94 and the hinge region of whole IgG. Grp94 does not form stable complex with Fab, F(ab)2 or Fc. Glycosylation turns out to be an obstacle to the Grp94 binding to IgG, although this negative effect can be counteracted by ATP and spontaneously also disappears in time in a physiological setting of incubation. ATP does not affect at all the binding capacity of non-glycosylated Grp94. However, complexes that native, partially glycosylated Grp94 forms with IgG in the presence of ATP show strikingly different characteristics with respect to those formed in absence of ATP. Results have relevance for the mechanism regulating the formation of stable Grp94-IgG complexes in vivo, in the pathological conditions associated with the extra-cellular location of Grp94.
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Huang SH, Zhao LX, Hong C, Duo CC, Guo BN, Zhang LJ, Gong Z, Xiong SD, Gong FY, Gao XM. Self-oligomerization is essential for enhanced immunological activities of soluble recombinant calreticulin. PLoS One 2013; 8:e64951. [PMID: 23762269 PMCID: PMC3677884 DOI: 10.1371/journal.pone.0064951] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Accepted: 04/19/2013] [Indexed: 12/11/2022] Open
Abstract
We have recently reported that calreticulin (CRT), a luminal resident protein, can be found in the sera of patients with rheumatoid arthritis and also that recombinant CRT (rCRT) exhibits extraordinarily strong immunological activities. We herein further demonstrate that rCRT fragments 18-412 (rCRT/18-412), rCRT/39-272, rCRT/120-308 and rCRT/120-250 can self-oligomerize in solution and are 50-100 fold more potent than native CRT (nCRT, isolated from mouse livers) in activating macrophages in vitro. We narrowed down the active site of CRT to residues 150-230, the activity of which also depends on dimerization. By contrast, rCRT/18-197 is almost completely inactive. When rCRT/18-412 is fractionated into oligomers and monomers by gel filtration, the oligomers maintain most of their immunological activities in terms of activating macrophages in vitro and inducing specific antibodies in vivo, while the monomers were much less active by comparison. Additionally, rCRT/18-412 oligomers are much better than monomers in binding to, and uptake by, macrophages. Inhibition of macrophage endocytosis partially blocks the stimulatory effect of rCRT/18-412. We conclude that the immunologically active site of CRT maps between residues 198-230 and that soluble CRT could acquire potent immuno-pathological activities in microenvironments favoring its oligomerization.
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Affiliation(s)
- Shang-Hui Huang
- Institute of Biology and Medical Sciences, Soochow University, Suzhou, Jiangsu Province, China
| | - Li-Xiang Zhao
- Institute of Biology and Medical Sciences, Soochow University, Suzhou, Jiangsu Province, China
| | - Chao Hong
- Institute of Biology and Medical Sciences, Soochow University, Suzhou, Jiangsu Province, China
| | - Cui-Cui Duo
- Institute of Biology and Medical Sciences, Soochow University, Suzhou, Jiangsu Province, China
| | - Bing-Nan Guo
- Institute of Biology and Medical Sciences, Soochow University, Suzhou, Jiangsu Province, China
| | - Li-Juan Zhang
- Institute of Biology and Medical Sciences, Soochow University, Suzhou, Jiangsu Province, China
| | - Zheng Gong
- Institute of Biology and Medical Sciences, Soochow University, Suzhou, Jiangsu Province, China
| | - Si-Dong Xiong
- Institute of Biology and Medical Sciences, Soochow University, Suzhou, Jiangsu Province, China
| | - Fang-Yuan Gong
- Institute of Biology and Medical Sciences, Soochow University, Suzhou, Jiangsu Province, China
- * E-mail: (XMG); (FYG)
| | - Xiao-Ming Gao
- Institute of Biology and Medical Sciences, Soochow University, Suzhou, Jiangsu Province, China
- * E-mail: (XMG); (FYG)
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Liu B, Staron M, Li Z. Murine but not human basophil undergoes cell-specific proteolysis of a major endoplasmic reticulum chaperone. PLoS One 2012; 7:e39442. [PMID: 22724016 PMCID: PMC3377640 DOI: 10.1371/journal.pone.0039442] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2012] [Accepted: 05/24/2012] [Indexed: 11/26/2022] Open
Abstract
Introduction Basophil has been implicated in anti-parasite defense, allergy and in polarizing TH2 response. Mouse model has been commonly used to study basophil function although the difference between human and mouse basophils is underappreciated. As an essential chaperone for multiple Toll-like receptors and integrins in the endoplasmic reticulum, gp96 also participates in general protein homeostasis and in the ER unfolded protein response to ensure cell survival during stress. The roles of gp96 in basophil development are unknown. Methods We genetically delete gp96 in mice and examined the expression of gp96 in basophils by Western blot and flow cytometry. We compared the expression pattern of gp96 between human and mouse basophils. Results We found that gp96 was dispensable for murine basophil development. Moreover, gp96 was cleaved by serine protease(s) in murine but not human basophils leading to accumulation of a nun-functional N-terminal ∼50 kDa fragment and striking induction of the unfolded protein response. The alteration of gp96 was unique to basophils and was not observed in any other cell types including mast cells. We also demonstrated that the ectopic expression of a mouse-specific tryptase mMCP11 does not lead to gp96 cleavage in human basophils. Conclusions Our study revealed a remarkable biochemical event of gp96 silencing in murine but not human basophils, highlighting the need for caution in using mouse models to infer the function of basophils in human immune response. Our study also reveals a novel mechanism of shutting down gp96 post-translationally in regulating its function.
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Affiliation(s)
- Bei Liu
- Department of Microbiology and Immunology, Hollings Cancer Center, Medical University of South Carolina (MUSC), Charleston, South Carolina, USA.
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Marzec M, Eletto D, Argon Y. GRP94: An HSP90-like protein specialized for protein folding and quality control in the endoplasmic reticulum. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2011; 1823:774-87. [PMID: 22079671 DOI: 10.1016/j.bbamcr.2011.10.013] [Citation(s) in RCA: 275] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2011] [Revised: 10/25/2011] [Accepted: 10/25/2011] [Indexed: 02/06/2023]
Abstract
Glucose-regulated protein 94 is the HSP90-like protein in the lumen of the endoplasmic reticulum and therefore it chaperones secreted and membrane proteins. It has essential functions in development and physiology of multicellular organisms, at least in part because of this unique clientele. GRP94 shares many biochemical features with other HSP90 proteins, in particular its domain structure and ATPase activity, but also displays distinct activities, such as calcium binding, necessitated by the conditions in the endoplasmic reticulum. GRP94's mode of action varies from the general HSP90 theme in the conformational changes induced by nucleotide binding, and in its interactions with co-chaperones, which are very different from known cytosolic co-chaperones. GRP94 is more selective than many of the ER chaperones and the basis for this selectivity remains obscure. Recent development of molecular tools and functional assays has expanded the spectrum of clients that rely on GRP94 activity, but it is still not clear how the chaperone binds them, or what aspect of folding it impacts. These mechanistic questions and the regulation of GRP94 activity by other proteins and by post-translational modification differences pose new questions and present future research avenues. This article is part of a Special Issue entitled: Heat Shock Protein 90 (HSP90).
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Affiliation(s)
- Michal Marzec
- Department of Pathology and Lab Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
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Nciri R, Allagui MS, Bourogaa E, Saoudi M, Murat JC, Croute F, Elfeki A. Lipid peroxidation, antioxidant activities and stress protein (HSP72/73, GRP94) expression in kidney and liver of rats under lithium treatment. J Physiol Biochem 2011; 68:11-8. [PMID: 21948186 DOI: 10.1007/s13105-011-0113-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2011] [Accepted: 08/29/2011] [Indexed: 12/25/2022]
Abstract
The present work was aimed at studying the effects of a subchronic lithium treatment on rat liver and kidneys, paying attention to the relationship between lithium toxicity, oxidative stress, and stress protein expression. Male rats were submitted to lithium treatment by adding 2 g of lithium carbonate/kg of food for different durations up to 1 month. This treatment led to serum concentrations ranging from 0.5 mM (day 7) to 1.34 mM (day 28) and renal insufficiency highlighted by an increase of blood creatinine and urea levels and a decrease of urea excretion. Lithium treatment was found to trigger an oxidative stress both in kidney and liver, leading to an increase of lipid peroxidation level (TBARS) and of superoxide dismutase and catalase activities. Conversely, glutathione peroxidase activity was reduced. Constitutive HSP73 (heat shock protein 73) expression was not modified by lithium treatment, whereas inducible HSP72 was down-regulated in kidney. GRP94 (glucose regulated protein 94) appeared as two isoforms of 92 and 98 kDa: the 98-kDa protein being overexpressed in kidney by lithium treatment whereas 92-kDa protein was underexpressed both in kidney and liver.
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Affiliation(s)
- Riadh Nciri
- Laboratoire d'écophysiologie, Sfax, PB 802, 3018, Tunisia.
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8
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Eletto D, Dersh D, Argon Y. GRP94 in ER quality control and stress responses. Semin Cell Dev Biol 2010; 21:479-85. [PMID: 20223290 DOI: 10.1016/j.semcdb.2010.03.004] [Citation(s) in RCA: 168] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2010] [Accepted: 03/02/2010] [Indexed: 01/01/2023]
Abstract
A system of endoplasmic reticulum (ER) chaperones has evolved to optimize the output of properly folded secretory and membrane proteins. An important player in this network is Glucose Regulated Protein 94 (GRP94). Over the last decade, new structural and functional data have begun to delineate the unique characteristics of GRP94 and have solidified its importance in ER quality control pathways. This review describes our current understanding of GRP94 and the four ways in which it contributes to the ER quality control: (1) chaperoning the folding of proteins; (2) interacting with other components of the ER protein folding machinery; (3) storing calcium; and (4) assisting in the targeting of malfolded proteins to ER-associated degradation (ERAD).
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Affiliation(s)
- Davide Eletto
- Division of Cell Pathology, Department of Pathology and Lab Medicine, The Children's Hospital of Philadelphia and the University of Pennsylvania, 3615 Civic Center Blvd., Philadelphia, PA 19104, USA
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9
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Morales C, Wu S, Yang Y, Hao B, Li Z. Drosophila glycoprotein 93 Is an ortholog of mammalian heat shock protein gp96 (grp94, HSP90b1, HSPC4) and retains disulfide bond-independent chaperone function for TLRs and integrins. THE JOURNAL OF IMMUNOLOGY 2009; 183:5121-8. [PMID: 19786553 DOI: 10.4049/jimmunol.0900811] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Mammalian heat shock protein gp96 is an obligate chaperone for multiple integrins and TLRs, the mechanism of which is largely unknown. We have identified gp93 in Drosophila having high sequence homology to gp96. However, no functions were previously attributed to gp93. To determine whether gp93 and gp96 are functionally conserved, we have expressed gp93 in gp96-deficient mouse cells. Remarkably, the Drosophila gp93 is able to chaperone multiple murine gp96 clients including integrins alpha(4), alpha(L), and beta(2) and TLR2 and TLR9. This observation has led us to examine the structural basis of the chaperone function of gp96 by a close comparison between gp96 and gp93. We report that whereas gp96 undergoes intermolecular disulfide bond formation via Cys(138), gp93 is unable to do so due to the absence of a cysteine near the same region. However, abrogation of disulfide bond formation by substituting C with A (C138A) in gp96 via site-directed mutagenesis did not compromise its chaperone function. Likewise, gp93 chaperone ability could not be improved by forcing intermolecular bond formation between gp93 N termini. We conclude that gp93 is the Drosophila ortholog of gp96 and that the chaperone function of the two molecules is conserved. Moreover, gp96 N-terminal disulfide bond formation is not critical for its function, underscoring the importance of N-terminal dimerization via non-disulfide bond-mediated interactions in client protein folding by gp96. Further study of gp96 from an evolutionary angle shall be informative to uncover the detailed mechanism of its chaperone function of client proteins in the secretory pathway.
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Affiliation(s)
- Crystal Morales
- Department of Immunology, University of Connecticut School of Medicine, Farmington, CT 06030, USA
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10
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Krukenberg KA, Böttcher UMK, Southworth DR, Agard DA. Grp94, the endoplasmic reticulum Hsp90, has a similar solution conformation to cytosolic Hsp90 in the absence of nucleotide. Protein Sci 2009; 18:1815-27. [PMID: 19554567 PMCID: PMC2777357 DOI: 10.1002/pro.191] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2009] [Revised: 06/04/2009] [Accepted: 06/05/2009] [Indexed: 12/16/2022]
Abstract
The molecular chaperone, Hsp90, is an essential eukaryotic protein that assists in the maturation and activation of client proteins. Hsp90 function depends upon the binding and hydrolysis of ATP, which causes large conformational rearrangements in the chaperone. Hsp90 is highly conserved from bacteria to eukaryotes, and similar nucleotide-dependent conformations have been demonstrated for the bacterial, yeast, and human proteins. There are, however, important species-specific differences in the ability of nucleotide to shift the conformation from one state to another. Although the role of nucleotide in conformation has been well studied for the cytosolic yeast and human proteins, the conformations found in the absence of nucleotide are less well understood. In contrast to cytosolic Hsp90, crystal structures of the endoplasmic reticulum homolog, Grp94, show the same conformation in the presence of both ADP and AMPPNP. This conformation differs from the yeast AMPPNP-bound crystal state, suggesting that Grp94 may have a different conformational cycle. In this study, we use small angle X-ray scattering and rigid body modeling to study the nucleotide free states of cytosolic yeast and human Hsp90s, as well as mouse Grp94. We show that all three proteins adopt an extended, chair-like conformation distinct from the extended conformation observed for the bacterial Hsp90. For Grp94, we also show that nucleotide causes a small shift toward the crystal state, although the extended state persists as the major population. These results provide the first evidence that Grp94 shares a conformational state with other Hsp90 homologs.
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Affiliation(s)
- Kristin A Krukenberg
- Graduate Program in Chemistry and Chemical Biology, University of CaliforniaSan Francisco, California 94158
- Department of Biochemistry and Biophysics, University of CaliforniaSan Francisco, California 94158
| | - Ulrike M K Böttcher
- Department of Biochemistry and Biophysics, University of CaliforniaSan Francisco, California 94158
- Howard Hughes Medical Institute, University of CaliforniaSan Francisco, California 94158
| | - Daniel R Southworth
- Department of Biochemistry and Biophysics, University of CaliforniaSan Francisco, California 94158
- Howard Hughes Medical Institute, University of CaliforniaSan Francisco, California 94158
| | - David A Agard
- Department of Biochemistry and Biophysics, University of CaliforniaSan Francisco, California 94158
- Howard Hughes Medical Institute, University of CaliforniaSan Francisco, California 94158
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Ostrovsky O, Makarewich CA, Snapp EL, Argon Y. An essential role for ATP binding and hydrolysis in the chaperone activity of GRP94 in cells. Proc Natl Acad Sci U S A 2009; 106:11600-5. [PMID: 19553200 PMCID: PMC2710619 DOI: 10.1073/pnas.0902626106] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2009] [Indexed: 12/22/2022] Open
Abstract
Glucose-regulated protein 94 (GRP94) is an endoplasmic reticulum (ER) chaperone for which only few client proteins and no cofactors are known and whose mode of action is unclear. To decipher the mode of GRP94 action in vivo, we exploited our finding that GRP94 is necessary for the production of insulin-like growth factor (IGF)-II and developed a cell-based functional assay. Grp94(-/-) cells are hypersensitive to serum withdrawal and die. This phenotype can be complemented either with exogenous IGF-II or by expression of functional GRP94. Fusion proteins of GRP94 with monomeric GFP (mGFP) or mCherry also rescue the viability of transiently transfected, GRP94-deficient cells, demonstrating that the fusion proteins are functional. Because these constructs enable direct visualization of chaperone-expressing cells, we used this survival assay to assess the activities of GRP94 mutants that are defective in specific biochemical functions in vitro. Mutations that abolish binding of adenosine nucleotides cannot support growth in serum-free medium. Similarly, mutations of residues needed for ATP hydrolysis also render GRP94 partially or completely nonfunctional. In contrast, an N-terminal domain mutant that cannot bind peptides still supports cell survival. Thus the peptide binding activity in vitro can be uncoupled from the chaperone activity toward IGF in vivo. This mutational analysis suggests that the ATPase activity of GRP94 is essential for chaperone activity in vivo and that the essential protein-binding domain of GRP94 is distinct from the N-terminal domain.
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Affiliation(s)
- Olga Ostrovsky
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, PA 19104; and
| | - Catherine A. Makarewich
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, PA 19104; and
| | - Erik L. Snapp
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY 10461
| | - Yair Argon
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, PA 19104; and
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12
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Nezlin R. Circulating non-immune IgG complexes in health and disease. Immunol Lett 2009; 122:141-4. [PMID: 19189847 DOI: 10.1016/j.imlet.2009.01.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2008] [Revised: 01/11/2009] [Accepted: 01/11/2009] [Indexed: 11/28/2022]
Abstract
IgG molecules possess a well-defined ability to form complexes with various proteins at interaction sites composed of residues of the constant domains. Such non-immune complexes (non-ICs) were recently identified in the circulatory system of healthy people, as well as patients suffering from various pathologies. By forming non-ICs, attached proteins that are harmful to the organism (anaphylatoxins, for example) are removed from the circulation. Non-immune IgG complexes can react simultaneously with two cell receptors-one specific for IgG, and another specific for an associated protein. Such double reactions augment cellular responses. The attachment of a protein to an IgG site may induce structural changes in neighboring areas of IgG molecules. The formation of non-ICs helps proteins with low molecular mass to escape glomerular filtration, as well as enzymatic degradation and cell uptake. Non-immune IgG complexes have been found in commercial immune globulin preparations used for the treatment of various diseases. Among the IgG-attached proteins, there are specific disease biomarkers used for clinical diagnostics and understanding disease processes. Therefore, in order to identify potential biomarkers, not only proteins that are free in the liquid phase of serum but also proteins associated with abundant proteins such as IgG must be investigated.
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Affiliation(s)
- Roald Nezlin
- Department of Immunology, Weizmann Institute of Science, Rehovot 76100, Israel.
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13
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Saitoh SI, Miyake K. Regulatory molecules required for nucleotide-sensing Toll-like receptors. Immunol Rev 2009; 227:32-43. [DOI: 10.1111/j.1600-065x.2008.00729.x] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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14
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Tramentozzi E, Montopoli M, Orso G, Pagetta A, Caparrotta L, Frasson M, Brunati AM, Finotti P. Stable complexes formed by Grp94 with human IgG promoting angiogenic differentiation of HUVECs by a cytokine-like mechanism. Mol Immunol 2008; 45:3639-48. [PMID: 18554719 DOI: 10.1016/j.molimm.2008.04.020] [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: 04/16/2008] [Accepted: 04/24/2008] [Indexed: 11/18/2022]
Abstract
To explore the molecular mechanisms by which complexes of Grp94 with IgG, purified from the plasma of diabetic subjects, could drive an inflammatory risk in vascular cells, native Grp94 was co-incubated with human, non-immune IgG to obtain the formation of complexes that were then tested on human umbilical vein endothelial cells (HUVECs). Co-incubation of Grp94 with IgG led to the formation of stable, SDS-resistant complexes that displayed effects partly similar and partly significantly different from those of Grp94 alone. Both Grp94 alone and with IgG stimulated the cell growth and promoted angiogenesis by a mechanism of autocrine/paracrine activation of the expression of heat shock protein (HSP)90 and HSP70. However, the most striking alterations in the cell cytoskeleton, characterized by dramatic rearrangement of actin and increased formation of podosomes, were induced by Grp94 with IgG, and were mediated by the enhanced expression of HSP90. At variance with Grp94 alone, Grp94 with IgG promoted the angiogenic differentiation by activating a signaling pathway apparently independent of the intense stimulation of the ERK1/2 pathway that was instead more directly involved in mediating the proliferative effects on HUVECs. Results show unprecedented cytokine-like effects of Grp94 and a so far undisclosed capacity to bind irreversibly IgG, forming complexes that, with respect to Grp94 alone, display a more intense angiogenic transforming capacity that may predict an increased inflammatory risk in vascular cells in vivo.
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Affiliation(s)
- Elisa Tramentozzi
- Department of Pharmacology and Anesthesiology, University of Padova, L.go E. Meneghetti 2, 35131 Padova, Italy
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15
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Sacho EJ, Kadyrov FA, Modrich P, Kunkel TA, Erie DA. Direct visualization of asymmetric adenine-nucleotide-induced conformational changes in MutL alpha. Mol Cell 2008; 29:112-21. [PMID: 18206974 DOI: 10.1016/j.molcel.2007.10.030] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2007] [Revised: 08/15/2007] [Accepted: 10/18/2007] [Indexed: 11/26/2022]
Abstract
MutL alpha, the heterodimeric eukaryotic MutL homolog, is required for DNA mismatch repair (MMR) in vivo. It has been suggested that conformational changes, modulated by adenine nucleotides, mediate the interactions of MutL alpha with other proteins in the MMR pathway, coordinating the recognition of DNA mismatches by MutS alpha and the activation of MutL alpha with the downstream events that lead to repair. Thus far, the only evidence for these conformational changes has come from X-ray crystallography of isolated domains, indirect biochemical analyses, and comparison to other members of the GHL ATPase family to which MutL alpha belongs. Using atomic force microscopy (AFM), coupled with biochemical techniques, we demonstrate that adenine nucleotides induce large asymmetric conformational changes in full-length yeast and human MutL alpha and that these changes are associated with significant increases in secondary structure. These data reveal an ATPase cycle in which sequential nucleotide binding, hydrolysis, and release modulate the conformational states of MutL alpha.
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Affiliation(s)
- Elizabeth J Sacho
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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16
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Frey S, Leskovar A, Reinstein J, Buchner J. The ATPase cycle of the endoplasmic chaperone Grp94. J Biol Chem 2007; 282:35612-20. [PMID: 17925398 DOI: 10.1074/jbc.m704647200] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Grp94, the Hsp90 paralog of the endoplasmic reticulum, plays a crucial role in protein secretion. Like cytoplasmic Hsp90, Grp94 is regulated by nucleotide binding to its N-terminal domain. However, the question of whether Grp94 hydrolyzes ATP was controversial. This sets Grp94 apart from other members of the Hsp90 family where a slow but specific turnover of ATP has been unambiguously established. In this study we aimed at analyzing the nucleotide binding properties and the potential ATPase activity of Grp94. We show here that Grp94 has an ATPase activity comparable with that of yeast Hsp90 with a k(cat) of 0.36 min(-1) at 25 degrees C. Kinetic and equilibrium constants of the partial reactions of the ATPase cycle were determined using transient kinetic methods. Nucleotide binding appears to be tighter compared with other Hsp90s investigated, with dissociation constants (K(D)) of approximately 4 microm for ADP, ATP, and AMP-PCP. Interestingly, all nucleotides and inhibitors (radicicol, 5'-N-ethylcarboxamidoadenosine) studied here bind with similar rate constants for association (0.2-0.3 x 10(6) M(-1) s(-1)). Furthermore, there is a marked difference from cytosolic Hsp90s in that after binding, the ATP molecule does not seem to become trapped by conformational changes in Grp94. Grp94 stays predominantly in the open state concerning the nucleotide-binding pocket as evidenced by kinetic analyses. Thus, Grp94 shows mechanistically important differences in the interaction with adenosine nucleotides, but the basic hydrolysis reaction seems to be conserved between cytosolic and endoplasmic members of the Hsp90 family.
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Affiliation(s)
- Stephan Frey
- Center for Integrated Protein Science and the Department of Chemistry, Technische Universität München, 85747 Garching, Germany
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17
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van den Akker E, Aarts LHJ, Delwel R. Viral insertion in Evi12 causes expression of aberrant Grp94 mRNAs containing the viral gag myristylation motif. Virology 2007; 366:227-33. [PMID: 17543366 DOI: 10.1016/j.virol.2007.04.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2007] [Revised: 02/15/2007] [Accepted: 04/25/2007] [Indexed: 11/15/2022]
Abstract
Ecotropic Virus Integration site 12 (Evi12) is a common virus insertion site (cVIS) in retrovirally induced murine models of leukemia and lymphoma, suggesting an important role for this locus in these hematopoietic disorders. Evi12 is located near the promoter of the ER chaperone protein and Hsp90 family member Grp94. Here we show that viral insertion in Evi12 results in the expression of aberrant Grp94 transcripts in Cas-Br-MuLV as well as in AKXD induced hematopoietic tumors, demonstrating that Grp94 is a common viral target gene. While most transcripts encode for truncated forms of Grp94, transcripts containing viral gag sequences were detected in the leukemia cell line NFS107. Interestingly, these fusion transcripts encode for myristylated viral-Grp94 fusion proteins that localize to the plasma membrane. Combined with recent evidence that myristylated forms of Hsp90 transform cells, our data suggest that myristylation of target genes may be an important mechanism in retrovirally mediated oncogenesis. Since retroviral insertion in Evi12 also affects the expression of a recently identified novel gene Grp94 neighboring nucleotidase (Gnn), located at the other side of Evi12, it appears that proviral insertion can lead to deregulation of two genes present in the same locus.
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Affiliation(s)
- Eric van den Akker
- Department of Hematology, Erasmus University Medical Center, Dr. Molewaterplein 50, 3015 GE Rotterdam, The Netherlands
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18
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Allagui MS, Vincent C, El feki A, Gaubin Y, Croute F. Lithium toxicity and expression of stress-related genes or proteins in A549 cells. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2007; 1773:1107-15. [PMID: 17512992 DOI: 10.1016/j.bbamcr.2007.04.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2007] [Revised: 04/16/2007] [Accepted: 04/16/2007] [Indexed: 02/08/2023]
Abstract
To unveil some molecular mechanisms underlying lithium toxicity, expression changes of stress-related genes or proteins were analysed in A549 cells, cultured for 3 days in presence of lithium. A dose-dependent cell-growth inhibition was found for concentrations ranging from 2 (toxicity threshold) to 12 mM (lethality threshold). cDNA arrays technology was used to analyse effects of 5 and 10 mM lithium. Among genes involved in cell cycle regulation, proliferating cell nuclear antigen (PCNA) was down-regulated and cyclin kinase inhibitor p21 (CDKN1A), up-regulated. Genes of paraoxonase 2, known to prevent LDL lipid peroxidation, and of catalase and SOD were found to be down-regulated whereas genes of cytochrome P450 (CYP2F1, CYP2E1) were up-regulated. This probably results in higher intracellular levels of reactive oxygen species and account for increased levels of lipid peroxidation commonly associated with lithium exposure. Moreover, lithium was found to down-regulate genes coding for anti-apoptotic gene BAG-1 and for most of the molecular chaperones (HSP, GRP). This might account for lithium toxicity since these proteins are critical for cell survival. At translational level, a 105 kDa protein was found to be over-expressed. This protein was recognized by the anti-GRP94, anti-KDEL and anti-phosphoserine monoclonal antibodies suggesting that, lithium could induce post-translational modifications of GRP94 phosphorylation. Using tunicamycin and thapsigargin, it was concluded that lithium effects are not related to defect in N-linked glycosylation and/or to changes in calcium homeostasis.
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Affiliation(s)
- M S Allagui
- Laboratoire de Biologie cellulaire et pollution, Faculté of Médicine-Purpan, Université Toulouse III 37, Allées Jules Guesde, 31073 Toulouse, France
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19
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Chu F, Maynard JC, Chiosis G, Nicchitta CV, Burlingame AL. Identification of novel quaternary domain interactions in the Hsp90 chaperone, GRP94. Protein Sci 2006; 15:1260-9. [PMID: 16731965 PMCID: PMC2242539 DOI: 10.1110/ps.052065106] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The structural basis for the coupling of ATP binding and hydrolysis to chaperone activity remains a central question in Hsp90 biology. By analogy to MutL, ATP binding to Hsp90 is thought to promote intramolecular N-terminal dimerization, yielding a molecular clamp functioning in substrate protein activation. Though observed in studies with recombinant domains, whether such quaternary states are present in native Hsp90s is unknown. In this study, native subunit interactions in GRP94, the endoplasmic reticulum Hsp90, were analyzed using chemical cross-linking in conjunction with tandem mass spectrometry. We report the identification of two distinct intermolecular interaction sites. Consistent with previous studies, one site comprises the C-terminal dimerization domain. The remaining site represents a novel intermolecular contact between the N-terminal and middle (M) domains of opposing subunits. This N+M domain interaction was present in the nucleotide-empty, ADP-, ATP-, or geldanamycin-bound states and could be selectively disrupted upon addition of synthetic geldanamycin dimers. These results identify a compact, intertwined quaternary conformation of native GRP94 and suggest that intersubunit N+M interactions are integral to the structural biology of Hsp90.
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Affiliation(s)
- Feixia Chu
- Mass Spectrometry Facility, University of California, San Francisco, California 94143, USA
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20
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Wang XY, Facciponte JG, Subjeck JR. Molecular chaperones and cancer immunotherapy. Handb Exp Pharmacol 2006:305-29. [PMID: 16610365 DOI: 10.1007/3-540-29717-0_13] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
As one of the most abundant and evolutionally conserved intracellular proteins, heat shock proteins, also known as stress proteins or molecular chaperones, perform critical functions in maintaining cell homeostasis under physiological as well as stress conditions. Certain chaperones in extracellular milieu are also capable of modulating innate and adaptive immunity due to their ability to chaperone polypeptides and to interact with the host's immune system, particularly professional antigen-presenting cells. The immunomodulating properties of chaperones have been exploited for cancer immunotherapy. Clinical trials using chaperone-based vaccines to treat various malignancies are ongoing.
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Affiliation(s)
- X Y Wang
- Department of Cellular Stress Biology and Urologic Oncology, Roswell Park Cancer Institute, Buffalo, NY 14263, USA.
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21
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Abstract
Oxidative folding in the endoplasmic reticulum is accomplished by a group of oxidoreductases where the protein disulfide isomerase (PDI) plays a key role. Structurally, redox-active PDI domains, like many other enzymes utilizing cysteine chemistry, adopt characteristic thioredoxin folds. However, this structural unit is not necessarily associated with the redox function and the current review focuses on the interesting example of a loss-of-function PDI-like protein from the endoplasmic reticulum, ERp29. ERp29 shares a common predecessor with PDI; however in the course of divergent evolution it has lost a hallmark active site motif of redox enzymes but retained the characteristic structural fold in one of its domains. Although the functional characterization of ERp29 is far from completion, all available data point to its important role in the early secretory pathway and allow tentative categorization as a secretion factor/escort protein of a broad profile.
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Affiliation(s)
- Souren Mkrtchian
- Section of Pharmacogenetics, Department of Physiology and Pharmacology, Karolinska Institute, Stockholm, Sweden.
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22
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Facciponte JG, Wang XY, MacDonald IJ, Park JE, Arnouk H, Grimm MJ, Li Y, Kim H, Manjili MH, Easton DP, Subjeck JR. Heat shock proteins HSP70 and GP96: structural insights. Cancer Immunol Immunother 2006; 55:339-46. [PMID: 16032399 PMCID: PMC11031057 DOI: 10.1007/s00262-005-0020-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2005] [Accepted: 04/25/2005] [Indexed: 10/25/2022]
Abstract
Several heat shock proteins (HSPs) act as potent adjuvants for eliciting anti-tumor immunity. HSP-based tumor vaccine strategies have been highly successful in animal models and are undergoing testing in clinical trials. It is generally accepted that HSPs, functioning as chaperones for tumor antigens, elicit tumor-specific adaptive immune responses. HSPs also appear to induce innate immune responses in an antigen-independent fashion. Innate responses generated by HSPs may contribute to anti-tumor immunity. Immunologically active chaperones with anti-tumor activity are referred to as "immunochaperones". Here, we review the studies that address the role of structural domains or regions of the immunochaperones HSP70 and GP96 that may be involved in the induction of adaptive or innate immune responses.
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Affiliation(s)
- John G Facciponte
- Department of Immunology, Roswell Park Cancer Institute, Buffalo, NY 14263, USA.
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23
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Fan H, Kashi RS, Middaugh CR. Conformational lability of two molecular chaperones Hsc70 and gp96: effects of pH and temperature. Arch Biochem Biophys 2006; 447:34-45. [PMID: 16487475 DOI: 10.1016/j.abb.2006.01.012] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2005] [Accepted: 01/15/2006] [Indexed: 10/25/2022]
Abstract
Hsc70 and gp96 are two heat shock proteins with molecular chaperone and immune-related activities. The dynamic conformational properties of heat shock proteins appear to play a critical role in their biological activities. In this study, we investigated the effects of pH and temperature on the conformational states of Hsc70 and gp96. The quaternary, tertiary, and secondary structures of both proteins are evaluated by a variety of spectroscopic techniques, including far-UV circular dichroism, Trp fluorescence, ANS fluorescence, and derivative UV absorption spectroscopy. The results are summarized and compared employing an empirical phase diagram approach. Very similar behaviors are seen for both proteins despite their differences in sequence and tertiary structure. Both proteins show substantial conformational lability in responses to the pH and temperature changes of their environment. This study suggests a natural selection for related functional properties through common conformational dynamics rather than immediate structural homology.
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Affiliation(s)
- Haihong Fan
- Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, KS 66047, USA
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24
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Huai Q, Wang H, Liu Y, Kim HY, Toft D, Ke H. Structures of the N-terminal and middle domains of E. coli Hsp90 and conformation changes upon ADP binding. Structure 2005; 13:579-90. [PMID: 15837196 DOI: 10.1016/j.str.2004.12.018] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2004] [Revised: 12/07/2004] [Accepted: 12/10/2004] [Indexed: 11/22/2022]
Abstract
Hsp90 is an abundant molecular chaperone involved in many biological systems. We report here the crystal structures of the unliganded and ADP bound fragments containing the N-terminal and middle domains of HtpG, an E. coli Hsp90. These domains are not connected through a flexible linker, as often portrayed in models, but are intimately associated with one another. The individual HtpG domains have similar folding to those of DNA gyrase B but assemble differently, suggesting somewhat different mechanisms for the ATPase superfamily. ADP binds to a subpocket of a large site that is jointly formed by the N-terminal and middle domains and induces conformational changes of the N-terminal domain. We speculate that this large pocket serves as a putative site for binding of client proteins/cochaperones. Modeling shows that ATP is not exposed to the molecular surface, thus implying that ATP activation of hsp90 chaperone activities is accomplished via conformational changes.
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Affiliation(s)
- Qing Huai
- Department of Biochemistry and Biophysics and Lineberger Comprehensive Cancer Center, The University of North Carolina, Chapel Hill, North Carolina 27599, USA
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25
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Scarlett DJG, Herst PM, Berridge MV. Multiple proteins with single activities or a single protein with multiple activities: the conundrum of cell surface NADH oxidoreductases. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2005; 1708:108-19. [PMID: 15882838 DOI: 10.1016/j.bbabio.2005.03.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2004] [Revised: 03/13/2005] [Accepted: 03/14/2005] [Indexed: 10/25/2022]
Abstract
Reduction of the cell-impermeable tetrazolium salt WST-1 has been used to characterise two plasma membrane NADH oxidoreductase activities in human cells. The trans activity, measured with WST-1 and the intermediate electron acceptor mPMS, utilises reducing equivalents from intracellular sources, while the surface activity, measured with WST-1 and extracellular NADH, is independent of intracellular metabolism. Whether these two activities involve distinct proteins or are inherent to a single protein is unclear. In this work, we have attempted to address this question by examining the relationship between the trans and surface WST-1-reducing activities and a third well-characterised family of cell surface oxidases, the ECTO-NOX proteins. Using blue native-polyacrylamide gel electrophoresis, we have identified a complex in the plasma membranes of human 143B osteosarcoma cells responsible for the NADH-dependent reduction of WST-1. The dye-reducing activity of the 300 kDa complex was attributed to a 70 kDa NADH oxidoreductase activity that cross-reacted with antisera against the ECTO-NOX protein CNOX. Differences in enzyme activities and inhibitor profiles between the WST-1-reducing NADH oxidoreductase enzyme in the presence of NADH or mPMS and the ECTO-NOX family are reconciled in terms of the different purification methods and assay systems used to study these proteins.
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26
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Zhao TJ, Ou WB, Xie Q, Liu Y, Yan YB, Zhou HM. Catalysis of Creatine Kinase Refolding by Protein Disulfide Isomerase Involves Disulfide Cross-link and Dimer to Tetramer Switch. J Biol Chem 2005; 280:13470-6. [PMID: 15695804 DOI: 10.1074/jbc.m413882200] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Protein disulfide isomerase (PDI) functions as an isomerase to catalyze thiol:disulfide exchange, as a chaperone to assist protein folding, and as a subunit of prolyl-4-hydroxylase and microsomal triglyceride transfer protein. At a lower concentration of 0.2 microm, PDI facilitated the aggregation of unfolded rabbit muscle creatine kinase (CK) and exhibited anti-chaperone activity, which was shown to be mainly due to the hydrophobic interactions between PDI and CK and was independent of the cross-linking of disulfide bonds. At concentrations above 1 microm, PDI acted as a protector against aggregation but an inhibitor of reactivation during CK refolding. The inhibition effect of PDI on CK reactivation was further characterized as due to the formation of PDI-CK complexes through intermolecular disulfide bonds, a process involving Cys-36 and Cys-295 of PDI. Two disulfide-linked complexes containing both PDI and CK were obtained, and the large, soluble aggregates around 400 kDa were composed of 1 molecule of tetrameric PDI and 2 molecules of inactive intermediate dimeric CK, whereas the smaller one, around 200 kDa, was formed by 1 dimeric PDI and 1 dimeric CK. To our knowledge this is the first study revealing that PDI could switch its conformation from dimer to tetramer in its functions as a foldase. According to the observations in this research and our previous study of the folding pathways of CK, a working model was proposed for the molecular mechanism of CK refolding catalyzed by PDI.
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Affiliation(s)
- Tong-Jin Zhao
- Department of Biological Sciences and Biotechnology, Tsinghua University, Beijing, China
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27
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Thorne ME, McQuade KL. Heat-induced oligomerization of gp96 occurs via a site distinct from substrate binding and is regulated by ATP. Biochem Biophys Res Commun 2004; 323:1163-71. [PMID: 15451419 DOI: 10.1016/j.bbrc.2004.08.215] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2004] [Indexed: 10/26/2022]
Abstract
Gp96 (GRP94) is a dimeric glycoprotein and is the endoplasmic reticulum representative of the hsp90 family of molecular chaperones. In addition to the protein substrates it chaperones, gp96 binds weakly to both peptides and ATP, and has been shown to self-assemble into discrete oligomers upon heat shock at 50 degrees C, although physiological roles for these phenomena have not been well established. Our studies indicate that gp96 homooligomerizes irreversibly in vitro at temperatures as low as 42 degrees C and could involve pre-dissociation of dimers to monomers. Oligomerization is inhibited significantly by ATP; hydrolysis is not required, since ADP, ATP-gamma-S, and NECA inhibit self-assembly equally well. Peptide ligands do not competitively inhibit gp96 self-assembly and, in fact, bind to all oligomeric species, including the dimer. Together, these findings suggest that (1) heat-enhanced chaperone activity does not reside in oligomers per se, and (2) the regions of gp96 involved in peptide binding and oligomerization are distinct.
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Affiliation(s)
- Meghan E Thorne
- Department of Chemistry and Biochemistry, Bradley University, 1501 West Bradley Avenue, Peoria, IL 61625, USA
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28
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Liu C, Ewing N, DeFilippo M. Analytical challenges and strategies for the characterization of gp96-associated peptides. Methods 2004; 32:32-7. [PMID: 14624875 DOI: 10.1016/s1046-2023(03)00185-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
This paper describes the methods that were used for the preparation of gp96-associated peptides and the analysis of these peptides using mass spectrometry. A general approach for stripping, enriching, and separating peptides associated with gp96 is presented. Protocols for the demonstration of the diversity of gp96-associated peptides using mass spectrometry and the identification of these peptides using a combination of tandem mass spectrometry and protein database searching are described. Important parameters and factors that affect the outcome of the experiments are discussed.
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29
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Jørgensen CS, Ryder LR, Steinø A, Højrup P, Hansen J, Beyer NH, Heegaard NHH, Houen G. Dimerization and oligomerization of the chaperone calreticulin. ACTA ACUST UNITED AC 2003; 270:4140-8. [PMID: 14519126 DOI: 10.1046/j.1432-1033.2003.03808.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The chaperone calreticulin is a highly conserved eukaryotic protein mainly located in the endoplasmic reticulum. It contains a free cysteine SH group but does not form disulfide-bridged dimers under physiological conditions, indicating that the SH group may not be fully accessible in the native protein. Using PAGE, urea gradient gel electrophoresis, capillary electrophoresis and MS, we show that dimerization through the SH group can be induced by lowering the pH to 5-6, heating, or under conditions that favour partial unfolding such as urea concentrations above 2.6 m or SDS concentrations above 0.025%. Moreover, we show that calreticulin also has the ability to self-oligomerize through noncovalent interactions at urea concentrations above 2.6 m at pH below 4.6 or above pH 10, at temperatures above 40 degrees C, or in the presence of high concentrations of organic solvents (25%), conditions that favour partial unfolding or an intramolecular local conformational change that allows oligomerization, resulting in a heterogeneous mixture of oligomers consisting of up to 10 calreticulin monomers. The oligomeric calreticulin was very stable, but oligomerization was partially reversed by addition of 8 m urea or 1% SDS, and heat-induced oligomerization could be inhibited by 8 m urea or 1% SDS when present during heating. Comparison of the binding properties of monomeric and oligomeric calreticulin in solid-phase assays showed increased binding to peptides and denatured proteins when calreticulin was oligomerized. Thus, calreticulin shares the ability to self-oligomerize with other important chaperones such as GRP94 and HSP90, a property possibly associated with their chaperone activity.
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Soldano KL, Jivan A, Nicchitta CV, Gewirth DT. Structure of the N-terminal domain of GRP94. Basis for ligand specificity and regulation. J Biol Chem 2003; 278:48330-8. [PMID: 12970348 DOI: 10.1074/jbc.m308661200] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
GRP94, the endoplasmic reticulum (ER) paralog of the chaperone Hsp90, plays an essential role in the structural maturation or secretion of a subset of proteins destined for transport to the cell surface, such as the Toll-like receptors 2 and 4, and IgG, respectively. GRP94 differs from cytoplasmic Hsp90 by exhibiting very weak ATP binding and hydrolysis activity. GRP94 also binds selectively to a series of substituted adenosine analogs. The high resolution crystal structures at 1.75-2.1 A of the N-terminal and adjacent charged domains of GRP94 in complex with N-ethylcarboxamidoadenosine, radicicol, and 2-chlorodideoxyadenosine reveals a structural mechanism for ligand discrimination among hsp90 family members. The structures also identify a putative subdomain that may act as a ligand-responsive switch. The residues of the charged region fold into a disordered loop whose termini are ordered and continue the twisted beta sheet that forms the structural core of the N-domain. This continuation of the beta sheet past the charged domain suggests a structural basis for the association of the N-terminal and middle domains of the full-length chaperone.
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Affiliation(s)
- Karen L Soldano
- Departments of Biochemistry and Cell Biology, Duke University Medical Center, Durham, North Carolina 27710, USA
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31
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Pagetta A, Folda A, Brunati AM, Finotti P. Identification and purification from the plasma of Type 1 diabetic subjects of a proteolytically active Grp94Evidence that Grp94 is entirely responsible for plasma proteolytic activity. Diabetologia 2003; 46:996-1006. [PMID: 12827241 DOI: 10.1007/s00125-003-1133-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2002] [Revised: 02/06/2003] [Indexed: 02/01/2023]
Abstract
AIMS/HYPOTHESIS The overall increase in proteolytic activity in diabetes is known to be associated with the development and progression of vascular complications. Our aim was to investigate in detail the molecular nature of this activity in the plasma of Type 1 diabetic subjects. METHODS Plasma of both diabetic and control subjects was subjected to various purification procedures (ion exchange and affinity chromatography, HPLC, immunoprecipitation, electrophoresis, immunoblot and mass analyses) to identify the proteins of interest. Biological activities were measured on specific substrates. RESULTS In diabetic but not normal plasma we identified the presence of two heat shock proteins, Grp94 (Glucose-regulated protein94) and HSP70. The higher-than-normal proteolytic activity of Grp94 was: (i) directed against casein, but not against endogenous plasma proteins; (ii) fully and specifically inhibited only by anti-Grp94 polyclonal antibodies; and (iii) coupled with low-level ATPase activity. In addition, ATP binding to Grp94 was able to modulate proteolytic activity. We found that Grp94 in plasma circulates only as high molecular mass homo- and hetero-complexes, the latter mostly formed with IgG to which Grp94 is also linked by tenacious binding. Proteolytically-active Grp94 was purified by immunoprecipitation, which co-immunoprecipitated alpha(1)antitrypsin. CONCLUSION/INTERPRETATION Our results show the unexpected extracellular location and characteristic biological function of Grp94 even at a late stage of disease. These findings have physiopathological relevance for predicting activation of both autoimmune and inflammatory processes potentially associated with vascular complications.
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Affiliation(s)
- A Pagetta
- Department of Pharmacology and Anaesthesiology, University of Padova, Largo E. Meneghetti 2, 35131 Padua, Italy
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32
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Abstract
Heat shock proteins (hsps) are among the most abundant intracellular proteins. Their synthesis is rapidly up-regulated by various 'stressors' including temperature, glucose deprivation, infection and cancer. Certain hsps are able to: (i). associate and chaperone a large variety of cellular peptides; (ii). be efficiently internalized by antigen presenting cells (APC) through receptor-mediated endocytosis; (iii). channel antigenic peptides they chaperone in the APC's MHC class I presentation pathway; (iv). and stimulate inflammatory cytokines, chemokines and co-stimulatory molecules through the NFkappab signaling pathway. Extracellular release of hsps upon necrotic cell death and their modulated access at the surface of some cells, can be considered as a putative 'danger' signal. Based on the ancient origins and structural conservation of hsps, it has been proposed that, the role of hsps in immunity emerged early in evolution and to be widespread in extant organisms. Data from studies with the frog Xenopus support this proposition.
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Affiliation(s)
- Jacques Robert
- Department of Microbiology and Immunology, University of Rochester Medical Center, Box 672 601, Elmwood Avenue, Rochester, NY 14642, USA.
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33
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Yamada SI, Ono T, Mizuno A, Nemoto TK. A hydrophobic segment within the C-terminal domain is essential for both client-binding and dimer formation of the HSP90-family molecular chaperone. EUROPEAN JOURNAL OF BIOCHEMISTRY 2003; 270:146-54. [PMID: 12492485 DOI: 10.1046/j.1432-1033.2003.03375.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The alpha isoform of human 90-kDa heat shock protein (HSP90alpha) is composed of three domains: the N-terminal (residues 1-400); middle (residues 401-615) and C-terminal (residues 621-732). The middle domain is simultaneously associated with the N- and C-terminal domains, and the interaction with the latter mediates the dimeric configuration of HSP90. Besides one in the N-terminal domain, an additional client-binding site exists in the C-terminal domain of HSP90. The aim of the present study is to elucidate the regions within the C-terminal domain responsible for the bindings to the middle domain and to a client protein, and to define the relationship between the two functions. A bacterial two-hybrid system revealed that residues 650-697 of HSP90alpha were essential for the binding to the middle domain. An almost identical region (residues 657-720) was required for the suppression of heat-induced aggregation of citrate synthase, a model client protein. Replacement of either Leu665-Leu666 or Leu671-Leu672 to Ser-Ser within the hydrophobic segment (residues 662-678) of the C-terminal domain caused the loss of bindings to both the middle domain and the client protein. The interaction between the middle and C-terminal domains was also found in human 94-kDa glucose-regulated protein. Moreover, Escherichia coli HtpG, a bacterial HSP90 homologue, formed heterodimeric complexes with HSP90alpha and the 94-kDa glucose-regulated protein through their middle-C-terminal domains. Taken together, it is concluded that the identical region including the hydrophobic segment of the C-terminal domain is essential for both the client binding and dimer formation of the HSP90-family molecular chaperone and that the dimeric configuration appears to be similar in the HSP90-family proteins.
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Affiliation(s)
- Shin-ichi Yamada
- Division of Oral and Maxillofacial Surgery and Division of Oral Molecular Biology, Department of Developmental and Reconstructive Medicine, Course of Medical and Dental Sciences, Nagasaki University Graduate School of Biomedical Sciences, Japan
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Baker-LePain JC, Sarzotti M, Fields TA, Li CY, Nicchitta CV. GRP94 (gp96) and GRP94 N-terminal geldanamycin binding domain elicit tissue nonrestricted tumor suppression. J Exp Med 2002; 196:1447-59. [PMID: 12461080 PMCID: PMC2194266 DOI: 10.1084/jem.20020436] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2002] [Revised: 09/17/2002] [Accepted: 10/11/2002] [Indexed: 02/02/2023] Open
Abstract
In chemical carcinogenesis models, GRP94 (gp96) elicits tumor-specific protective immunity. The tumor specificity of this response is thought to reflect immune responses to GRP94-bound peptide antigens, the cohort of which uniquely identifies the GRP94 tissue of origin. In this study, we examined the apparent tissue restriction of GRP94-elicited protective immunity in a 4T1 mammary carcinoma model. We report that the vaccination of BALB/c mice with irradiated fibroblasts expressing a secretory form of GRP94 markedly suppressed 4T1 tumor growth and metastasis. In addition, vaccination with irradiated cells secreting the GRP94 NH(2)-terminal geldanamycin-binding domain (NTD), a region lacking canonical peptide-binding motifs, yielded a similar suppression of tumor growth and metastatic progression. Conditioned media from cultures of GRP94 or GRP94 NTD-secreting fibroblasts elicited the up-regulation of major histocompatibility complex class II and CD86 in dendritic cell cultures, consistent with a natural adjuvant function for GRP94 and the GRP94 NTD. Based on these findings, we propose that GRP94-elicited tumor suppression can occur independent of the GRP94 tissue of origin and suggest a primary role for GRP4 natural adjuvant function in antitumor immune responses.
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Affiliation(s)
- Julie C Baker-LePain
- Department of Cell Biology, Duke University Medical Center, 366 Nanaline H. Duke, Durham, NC 27710, USA
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35
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Vogen S, Gidalevitz T, Biswas C, Simen BB, Stein E, Gulmen F, Argon Y. Radicicol-sensitive peptide binding to the N-terminal portion of GRP94. J Biol Chem 2002; 277:40742-50. [PMID: 12189140 DOI: 10.1074/jbc.m205323200] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
GRP94 is a molecular chaperone that carries immunologically relevant peptides from cell to cell, transferring them to major histocompatibility proteins for presentation to T cells. Here we examine the binding of several peptides to recombinant GRP94 and study the regulation and site of peptide binding. We show that GRP94 contains a peptide-binding site in its N-terminal 355 amino acids. A number of peptides bind to this site with low on- and off-rates and with specificity that is distinct from that of another endoplasmic reticulum chaperone, BiP/GRP78. Binding to the N-terminal fragment is sufficient to account for the peptide binding activity of the entire molecule. Peptide binding is inhibited by radicicol, a known inhibitor of the chaperone activities of HSP90-family proteins. However, the peptide-binding site is distinct from the radicicol-binding pocket, because both can bind to the N-terminal fragment simultaneously. Furthermore, peptide binding does not cause the same conformational change as does binding of radicicol. When the latter binds to the N-terminal domain, it induces a conformational change in the downstream, acidic domain of GRP94, as measured by altered gel mobility and loss of an antibody epitope. These results relate the peptide-binding activity of GRP94 to its other function as a chaperone.
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Affiliation(s)
- Shawn Vogen
- Department of Pathology, Committees on Cell Physiology and Immunology, The University of Chicago, 5841 South Maryland Avenue, Chicago, IL 60637, USA
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36
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Ying M, Sannerud R, Flatmark T, Saraste J. Colocalization of Ca2+-ATPase and GRP94 with p58 and the effects of thapsigargin on protein recycling suggest the participation of the pre-Golgi intermediate compartment in intracellular Ca2+ storage. Eur J Cell Biol 2002; 81:469-83. [PMID: 12416724 DOI: 10.1078/0171-9335-00266] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
We have studied the localization of functional components of cellular Ca2+ transport and storage and the effects of thapsigargin (TG), a specific inhibitor of the sarco-endoplasmic reticulum Ca2+-ATPase (SERCA), with respect to the p58-containing pre-Golgi intermediate compartment (IC). The depletion of Ca2+ stores in normal rat kidney (NRK) cells by TG abolished the retention of the KDEL-containing, Ca2+-binding, luminal ER chaperones GRP94/endoplasmin and GRP78/BiP, and resulted in the appearance of the proteins in the culture medium before inducing their synthesis. Immunolocalization of GRP94 in TG-treated cells showed that the protein was transported to the Golgi complex and, in parallel, the KDEL receptor was redistributed from the Golgi to p58-positive IC structures, but was not transported further to the ER. Similarly, p58 that normally cycles between the ER, IC, and cis-Golgi, was largely depleted from the cell periphery and arrested in large-sized IC elements and numerous vesicles or buds in the Golgi region, showing that TG selectively blocks its recycling from the IC back to the ER. Importantly, cell fractionation analyses and confocal fluorescence microscopy provided evidence that the IC elements in unperturbed cells contain SERCA and a considerable pool of GRP94. Thus, the observed effects of TG on protein retention and recycling can be explained by a change in the luminal Ca2+ concentration of the IC. Moreover, the compositional properties of the IC elements suggest that they participate in intracellular Ca2+ storage.
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Affiliation(s)
- Ming Ying
- Department of Biochemistry and Molecular Biology, University of Bergen, Norway
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Reed RC, Zheng T, Nicchitta CV. GRP94-associated enzymatic activities. Resolution by chromatographic fractionation. J Biol Chem 2002; 277:25082-9. [PMID: 11983709 DOI: 10.1074/jbc.m203195200] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
GRP94 (gp96), which performs established functions as a molecular chaperone and immune system modulator, has been reported to display a number of intrinsic enzymatic activities, including ATP hydrolysis, protein phosphorylation, and aminopeptidase. In observing that GRP94 co-purified with bacterial beta-galactosidase through multiple chromatographic steps, we have examined the hypothesis that the reported enzymatic activities of GRP94 may reflect co-purification of contaminant enzymes, rather than intrinsic catalytic functions. In subjecting GRP94 to increasingly stringent chromatographic purification, we report that a GRP94 carboxyl-terminal directed protein kinase activity could be separated from GRP94 by heparin affinity chromatography. Analysis of the kinase substrate specificity indicates that this kinase is distinct from casein kinase II, which is known to co-purify with GRP94. Electrophoretically pure GRP94 displayed low, but significant levels of aminopeptidase activity. Further purification of GRP94 by anion exchange and heparin affinity chromatography yielded resolution of GRP94 from the aminopeptidase activity. Furthermore, exhaustive trypsinolysis of GRP94 preparations displaying aminopeptidase activity yielded complete proteolysis of GRP94 but did not affect aminopeptidase activity. These results are discussed with respect to current models for GRP94 function and the role of such co-purifying (poly)peptides in the generation of GRP94-dependent cellular immune responses.
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Affiliation(s)
- Robyn C Reed
- Department of Cell Biology, Duke University Medical Center, Durham, North Carolina 27710, USA
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Nemoto TK, Ono T, Kobayakawa T, Tanaka E, Baba TT, Tanaka K, Takagi T, Gotoh T. Domain-domain interactions of HtpG, an Escherichia coli homologue of eukaryotic HSP90 molecular chaperone. EUROPEAN JOURNAL OF BIOCHEMISTRY 2001; 268:5258-69. [PMID: 11606187 DOI: 10.1046/j.0014-2956.2001.02457.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In the present study, we investigated the domain structure and domain-domain interactions of HtpG, an Escherichia coli homologue of eukaryotic HSP90. Limited proteolysis of recombinant HtpG, revealed three major tryptic sites, i.e. Arg7-Gly8, Arg336-Glu337 and Lys552-Leu553, of which the latter two were located at the positions equivalent to the major cleavage sites of human HSP90alpha. A similar pattern was obtained by papain treatment under nondenaturing conditions but not under denaturing conditions. Thus, HtpG consists of three domains, i.e. Domain A, Met1-Arg336; domain B, Glu337-Lys552; and domain C, Leu553-Ser624, as does HSP90. The domains of HtpG were expressed and their interactions were estimated on polyacrylamide gel electrophoresis under nondenaturing conditions. As a result, two kinds of domain-domain interactions were revealed: domain B interaction with domain A of the same polypeptide and domain C of one partner with domain B of the other in the dimer. Domain B could be structurally and functionally divided into two subdomains, the N-terminal two-thirds (subdomain BI) that interacted with domain A and the C-terminal one-third (subdomain BII) that interacted with domain C. The C-terminal two-thirds of domain A, i.e. Asp116-Arg336, were sufficient for the binding to domain B. We finally propose the domain organization of an HtpG dimer.
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Affiliation(s)
- T K Nemoto
- Department of Oral Biochemistry, Nagasaki University School of Dentistry, Nagasaki, Japan.
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Tanaka E, Nemoto TK, Ono T. Liberation of the intramolecular interaction as the mechanism of heat-induced activation of HSP90 molecular chaperone. EUROPEAN JOURNAL OF BIOCHEMISTRY 2001; 268:5270-7. [PMID: 11606188 DOI: 10.1046/j.0014-2956.2001.02458.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The molecular chaperone function of HSP90 is activated under heat-stress conditions. In the present study, we investigated the role of the interactions in the heat-induced activation of HSP90 molecular chaperone. The preceding paper demonstrated two domain-domain interactions of HtpG, an Escherichia coli homologue of mammalian HSP90, i.e. an intra-molecular interaction between the N-terminal and middle domains and an intermolecular one between the middle and C-terminal domains. A bacterial two-hybrid system revealed that the two interactions also existed in human HSP90alpha. Partners of the interaction between the N-terminal and middle domains of human HSP90alpha could, but those between the middle and C-terminal domains could not, be replaced by the domains of HtpG. Thus, the interface between the N-terminal and middle domains is essentially unvaried from bacterial to human members of the HSP90-family proteins. The citrate synthase-binding activity of HtpG at an elevated temperature was solely localized in the N-terminal domain, but HSP90alpha possessed two sites in the N-terminal and other domains. The citrate-synthase-binding activity of the N-terminal domain was suppressed by the association of the middle domain. The complex between the N-terminal and middle domains is labile at elevated temperatures, but the other is stable even at 70 degrees C. Taken together, we propose the liberation of the N-terminal client-binding domain from the middle suppressor domain is involved in the temperature-dependent activation mechanism of HSP90 molecular chaperone.
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Affiliation(s)
- E Tanaka
- Department of Oral Biochemistry, Nagasaki University School of Dentistry, Nagasaki, Japan
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Takano S, Wadhwa R, Mitsui Y, Kaul SC. Identification and characterization of molecular interactions between glucose-regulated proteins (GRPs) mortalin/GRP75/peptide-binding protein 74 (PBP74) and GRP94. Biochem J 2001; 357:393-8. [PMID: 11439088 PMCID: PMC1221965 DOI: 10.1042/0264-6021:3570393] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
A heat-shock protein (hsp) 70 family member mortalin/glucose-regulated protein (GRP) 75/peptide-binding protein 74 (PBP74) has been localized to various cellular compartments including mitochondria, endoplasmic reticulum and cytoplasmic vesicles. Here we describe its interactions with an endoplasmic reticulum protein GRP94, a member of the hsp90 family of GRPs. Interactions were identified, confirmed and characterized by far-Western screening, in vivo reporter and co-immunoprecipitation assays. Interacting domains of the two proteins were also characterized by mutational analysis. Such interactions of these two GRPs may be important for function of either or both and therefore provide important information for further studies.
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Affiliation(s)
- S Takano
- Institute of Molecular and Cell Biology, National Institute of Advanced Industrial Science and Technology, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8566, Japan
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41
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Liepinsh E, Baryshev M, Sharipo A, Ingelman-Sundberg M, Otting G, Mkrtchian S. Thioredoxin fold as homodimerization module in the putative chaperone ERp29: NMR structures of the domains and experimental model of the 51 kDa dimer. Structure 2001; 9:457-71. [PMID: 11435111 DOI: 10.1016/s0969-2126(01)00607-4] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND ERp29 is a ubiquitously expressed rat endoplasmic reticulum (ER) protein conserved in mammalian species. Fold predictions suggest the presence of a thioredoxin-like domain homologous to the a domain of human protein disulfide isomerase (PDI) and a helical domain similar to the C-terminal domain of P5-like PDIs. As ERp29 lacks the double-cysteine motif essential for PDI redox activity, it is suggested to play a role in protein maturation and/or secretion related to the chaperone function of PDI. ERp29 self-associates into 51 kDa dimers and also higher oligomers. RESULTS 3D structures of the N- and C-terminal domains determined by NMR spectroscopy confirmed the thioredoxin fold for the N-terminal domain and yielded a novel all-helical fold for the C-terminal domain. Studies of the full-length protein revealed a short, flexible linker between the two domains, homodimerization by the N-terminal domain, and the presence of interaction sites for the formation of higher molecular weight oligomers. A gadolinium-based relaxation agent is shown to present a sensitive tool for the identification of macromolecular interfaces by NMR. CONCLUSIONS ERp29 is the first eukaryotic PDI-related protein for which the structures of all domains have been determined. Furthermore, an experimental model of the full-length protein and its association states was established. It is the first example of a protein where the thioredoxin fold was found to act as a specific homodimerization module, without covalent linkages or supporting interactions by further domains. A homodimerization module similar as in ERp29 may also be present in homodimeric human PDI.
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Affiliation(s)
- E Liepinsh
- Department of Medical Biochemistry and Biophysics, Karolinska Institute, 171 77, Stockholm, Sweden
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Linderoth NA, Simon MN, Hainfeld JF, Sastry S. Binding of antigenic peptide to the endoplasmic reticulum-resident protein gp96/GRP94 heat shock chaperone occurs in higher order complexes. Essential role of some aromatic amino acid residues in the peptide-binding site. J Biol Chem 2001; 276:11049-54. [PMID: 11148208 DOI: 10.1074/jbc.m010059200] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Vaccination with heat shock protein gp96-antigenic peptide complexes produces a powerful specific immune response against cancers and infectious diseases in some experimental animal models, and gp96-peptide complexes are now being tested in human clinical trials. gp96 appears to serve as a natural adjuvant for chaperoning antigenic peptides into the immune surveillance pathways. A fundamental issue that needs to be addressed is the mechanism of binding of antigenic peptide to gp96. Here, we show using scanning transmission electron microscopy that recombinant gp96 binds peptide in stable multimeric complexes, which may have biological significance. To open the possibility for genetically engineering gp96 for improved immunogenicity and to understand if molecular recognition plays a role in the binding of antigenic peptide, we mutagenized some specific aromatic amino acids in the presumed peptide-binding pocket. Replacement of Tyr-667 or Tyr-678 to Ala reduced affinity for peptide whereas conversion of Trp-654 to Tyr increased peptide binding. Similarly, changing Trp-621 to Phe or Leu or Ala or Ile negatively affected peptide binding whereas changing Trp-621 to Tyr or Val positively affected peptide binding. Probing the peptide microenvironment in gp96-peptide complexes, suggested that hydrophobic interactions (and perhaps hydrogen bonding/stacking interactions) may play a role in peptide loading by gp96.
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Affiliation(s)
- N A Linderoth
- Laboratory of Molecular Genetics, The Rockefeller University, New York, New York 10021 and the Department of Biology, Brookhaven National Laboratory, Upton, New York 11973
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Roher N, Miró F, Boldyreff B, Llorens F, Plana M, Issinger OG, Itarte E. The C-terminal domain of human grp94 protects the catalytic subunit of protein kinase CK2 (CK2alpha) against thermal aggregation. Role of disulfide bonds. EUROPEAN JOURNAL OF BIOCHEMISTRY 2001; 268:429-36. [PMID: 11168379 DOI: 10.1046/j.1432-1033.2001.01905.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The C-terminal domain (residues 518-803) of the 94 kDa glucose regulated protein (grp94) was expressed in Escherichia coli as a fusion protein with a His6-N-terminal tag (grp94-CT). This truncated form of grp94 formed dimers and oligomers that could be dissociated into monomers by treatment with dithiothreitol. Grp94-CT conferred protection against aggregation on the catalytic subunit of protein kinase CK2 (CK2alpha), although it did not protect against thermal inactivation. This anti-aggregation effect of grp94-CT was concentration dependent, with full protection achieved at grp94-CT/CK2alpha molar ratios of 4 : 1. The presence of dithiothreitol markedly reduced the anti-aggregation effects of grp94-CT on CK2alpha without altering the solubility of the chaperone. It is concluded that the chaperone activity of the C-terminal domain of human grp94 requires the maintenance of its quaternary structure (dimers and oligomers), which seems to be stabilised by disulphide bonds.
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Affiliation(s)
- N Roher
- Departament de Bioquímica i Biologia Molecular. Facultat de Ciències, Universitat Autònoma de Barcelona, Spain
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Prodromou C, Panaretou B, Chohan S, Siligardi G, O'Brien R, Ladbury JE, Roe SM, Piper PW, Pearl LH. The ATPase cycle of Hsp90 drives a molecular 'clamp' via transient dimerization of the N-terminal domains. EMBO J 2000; 19:4383-92. [PMID: 10944121 PMCID: PMC302038 DOI: 10.1093/emboj/19.16.4383] [Citation(s) in RCA: 367] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
How the ATPase activity of Heat shock protein 90 (Hsp90) is coupled to client protein activation remains obscure. Using truncation and missense mutants of Hsp90, we analysed the structural implications of its ATPase cycle. C-terminal truncation mutants lacking inherent dimerization displayed reduced ATPase activity, but dimerized in the presence of 5'-adenylamido-diphosphate (AMP-PNP), and AMP-PNP- promoted association of N-termini in intact Hsp90 dimers was demonstrated. Recruitment of p23/Sba1 to C-terminal truncation mutants also required AMP-PNP-dependent dimerization. The temperature- sensitive (ts) mutant T101I had normal ATP affinity but reduced ATPase activity and AMP-PNP-dependent N-terminal association, whereas the ts mutant T22I displayed enhanced ATPase activity and AMP-PNP-dependent N-terminal dimerization, indicating a close correlation between these properties. The locations of these residues suggest that the conformation of the 'lid' segment (residues 100-121) couples ATP binding to N-terminal association. Consistent with this, a mutation designed to favour 'lid' closure (A107N) substantially enhanced ATPase activity and N-terminal dimerization. These data show that Hsp90 has a molecular 'clamp' mechanism, similar to DNA gyrase and MutL, whose opening and closing by transient N-terminal dimerization are directly coupled to the ATPase cycle.
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Affiliation(s)
- C Prodromou
- Section of Structural Biology, Institute of Cancer Research, Chester Beatty Laboratories, 237 Fulham Road, London SW3 6JB, UK
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Rosser MF, Nicchitta CV. Ligand interactions in the adenosine nucleotide-binding domain of the Hsp90 chaperone, GRP94. I. Evidence for allosteric regulation of ligand binding. J Biol Chem 2000; 275:22798-805. [PMID: 10816561 DOI: 10.1074/jbc.m001477200] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
X-ray crystallographic studies of the N-terminal domain of Hsp90 have identified an unconventional ATP binding fold, thereby inferring a role for ATP in the regulation of the Hsp90 activity. In this report, N-ethylcarboxamidoadenosine (NECA) was used to investigate the nucleotide binding properties of GRP94, the endoplasmic reticulum paralog of Hsp90. Whereas Hsp90 did not bind NECA, GRP94 bound NECA in a saturable manner with a K(d) of 200 nm. NECA binding to GRP94 was efficiently blocked by geldanamycin and radicicol. Analysis of ligand binding stoichiometries by radioligand and calorimetric techniques indicated that GRP94 bound 1 mol of NECA/mol of GRP94 dimer. In contrast, GRP94 bound radicicol at a stoichiometry of 2 mol of radicicol/mol of GRP94 dimer. In [(3)H]NECA displacement assays, GRP94 displayed binding interactions with ATP, dATP, ADP, AMP, cAMP, and adenosine, but not GTP, CTP, or UTP. To accommodate the 0.5 mol of NECA:mol of GRP94 binding stoichiometry observed for the native GRP94 dimer, a model for allosteric regulation (negative cooperativity) of ligand binding is proposed. A hypothesis on the regulation of GRP94 conformation and activity by adenosine-based ligand(s) other than ATP and ADP is presented.
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Affiliation(s)
- M F Rosser
- Department of Cell Biology, Box 3709, Duke University Medical Center, Durham, North Carolina 27710, USA
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Wassenberg JJ, Reed RC, Nicchitta CV. Ligand interactions in the adenosine nucleotide-binding domain of the Hsp90 chaperone, GRP94. II. Ligand-mediated activation of GRP94 molecular chaperone and peptide binding activity. J Biol Chem 2000; 275:22806-14. [PMID: 10816560 DOI: 10.1074/jbc.m001476200] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The N-terminal domain of eukaryotic Hsp90 proteins contains a conserved adenosine nucleotide binding pocket that also serves as the binding site for the Hsp90 inhibitors geldanamycin and radicicol. Although this domain is essential for Hsp90 function, the molecular basis for adenosine nucleotide-dependent regulation of GRP94, the endoplasmic reticulum paralog of Hsp90, remains to be established. We report that bis-ANS (1,1'-bis(4-anilino-5-napthalenesulfonic acid), an environment sensitive fluorophore known to interact with nucleotide-binding domains, binds to the adenosine nucleotide-binding domain of GRP94 and thereby activates its molecular chaperone and peptide binding activities. bis-ANS was observed to elicit a tertiary conformational change in GRP94 similar to that occurring upon heat shock, which also activates GRP94 function. bis-ANS activation of GRP94 function was efficiently blocked by radicicol, an established inhibitory ligand for the adenosine nucleotide binding pocket. Confirmation of the N-terminal nucleotide binding pocket as the bis-ANS-binding site was obtained following covalent incorporation of bis-ANS into GRP94, trypsinolysis, and sequencing of bis-ANS-labeled limit digestion products. These data identify a ligand dependent regulation of GRP94 function and suggest a model whereby GRP94 function is regulated through a ligand-dependent conversion of GRP94 from an inactive to an active conformation.
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Affiliation(s)
- J J Wassenberg
- Department of Cell Biology, Box 3709, Duke University Medical Center, Durham, North Carolina 27710, USA
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Cho G, Suh SW, Jung G. HBV polymerase interacts independently with N-terminal and C-terminal fragments of Hsp90beta. Biochem Biophys Res Commun 2000; 274:203-11. [PMID: 10903919 DOI: 10.1006/bbrc.2000.3119] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Hsp90 is an abundant chaperone protein that assists the folding of specific proteins, such as steroid receptors, protein kinases, and so on, for their proper function. TP and RT domains of HBV polymerase have been also shown to be associated with Hsp90. Therefore, the identification of the binding sites within Hsp90, responsible for forming Hsp90/HBV Pol complex, is important for the understanding of HBV replication. In this study, cotransfection and immunoprecipitation experiments were performed to localize the binding sites of HBV pol to Hsp90. Our data show that HBV pol interact independently with both N-terminal and C-terminal fragments of Hsp90. Further analysis showed that N-terminal fragment (1-302) of Hsp90 interacts with both TP and RT domains of HBV pol, whereas C-terminal fragment (438-723) interacts with only RT domain. In conclusion, we showed that HBV pol independently interacts with N-terminal and C-terminal fragments, but not the middle fragment (327-438) of Hsp90.
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Affiliation(s)
- G Cho
- School of Biological Science, Seoul National University, Seoul, 151-742, Korea
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48
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Singh-Jasuja H, Toes RE, Spee P, Münz C, Hilf N, Schoenberger SP, Ricciardi-Castagnoli P, Neefjes J, Rammensee HG, Arnold-Schild D, Schild H. Cross-presentation of glycoprotein 96-associated antigens on major histocompatibility complex class I molecules requires receptor-mediated endocytosis. J Exp Med 2000; 191:1965-74. [PMID: 10839811 PMCID: PMC2213530 DOI: 10.1084/jem.191.11.1965] [Citation(s) in RCA: 261] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Heat shock proteins (HSPs) like glycoprotein (gp)96 (glucose-regulated protein 94 [grp94]) are able to induce specific cytotoxic T lymphocyte (CTL) responses against cells from which they originate. Here, we demonstrate that for CTL activation by gp96-chaperoned peptides, specific receptor-mediated uptake of gp96 by antigen-presenting cells (APCs) is required. Moreover, we show that in both humans and mice, only professional APCs like dendritic cells (DCs), macrophages, and B cells, but not T cells, are able to bind gp96. The binding is saturable and can be inhibited using unlabeled gp96 molecules. Receptor binding by APCs leads to a rapid internalization of gp96, which colocalizes with endocytosed major histocompatibility complex (MHC) class I and class II molecules in endosomal compartments. Incubation of gp96 molecules isolated from cells expressing an adenovirus type 5 E1B epitope with the DC line D1 results in the activation of E1B-specific CTLs. This CTL activation can be specifically inhibited by the addition of irrelevant gp96 molecules not associated with E1B peptides. Our results demonstrate that only receptor-mediated endocytosis of gp96 molecules leads to MHC class I-restricted re-presentation of gp96-associated peptides and CTL activation; non-receptor-mediated, nonspecific endocytosis is not able to do so. Thus, we provide evidence on the mechanisms by which gp96 is participating in the cross-presentation of antigens from cellular origin.
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Affiliation(s)
- Harpreet Singh-Jasuja
- Institute for Cell Biology, Department of Immunology, University of Tübingen, D-72076 Tübingen, Germany
| | - René E.M. Toes
- Department of Immunohematology and Transfusion Bank, Leiden University Medical Center, 2300 RC Leiden, The Netherlands
| | - Pieter Spee
- Division of Tumor Biology, The Netherlands Cancer Institute, 1066 CX Amsterdam, The Netherlands
| | - Christian Münz
- Laboratory of Cellular Physiology and Immunology, The Rockefeller University, New York, New York 10021
| | - Norbert Hilf
- Institute for Cell Biology, Department of Immunology, University of Tübingen, D-72076 Tübingen, Germany
| | - Stephen P. Schoenberger
- Department of Immunohematology and Transfusion Bank, Leiden University Medical Center, 2300 RC Leiden, The Netherlands
| | | | - Jacques Neefjes
- Division of Tumor Biology, The Netherlands Cancer Institute, 1066 CX Amsterdam, The Netherlands
| | - Hans-Georg Rammensee
- Institute for Cell Biology, Department of Immunology, University of Tübingen, D-72076 Tübingen, Germany
| | - Danièle Arnold-Schild
- Institute for Cell Biology, Department of Immunology, University of Tübingen, D-72076 Tübingen, Germany
| | - Hansjörg Schild
- Institute for Cell Biology, Department of Immunology, University of Tübingen, D-72076 Tübingen, Germany
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49
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Linderoth NA, Popowicz A, Sastry S. Identification of the peptide-binding site in the heat shock chaperone/tumor rejection antigen gp96 (Grp94). J Biol Chem 2000; 275:5472-7. [PMID: 10681525 DOI: 10.1074/jbc.275.8.5472] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Heat shock protein (HSP)-peptide complexes from tumor cells elicit specific protective immunity when injected into inbred mice bearing the same specific type of tumor. The HSP-mediated specific immunogenicity also occurs with virus-infected cells. The immune response is solely due to endogenous peptides noncovalently bound to HSP. A vesicular stomatitis virus capsid-derived peptide ligand bearing a photoreactive azido group was specifically bound by and cross-linked to murine HSP glycoprotein (gp) 96. The peptide-binding site was mapped by specific proteolysis of the cross-links followed by analysis of the cross-linked peptides using a judicious combination of SDS-gel electrophoresis, mass spectrometry, and amino acid sequencing. The minimal peptide-binding site was mapped to amino acid residues 624-630 in a highly conserved region of gp96. A model of the peptide binding pocket of gp96 was constructed based on the known crystallographic structure of major histocompatibility complex class I molecule bound to a similar peptide. The gp96-peptide model predicts that the peptide ligand is held in a groove formed by alpha-helices and lies on a surface consisting of antiparallel beta-sheets. Interestingly, in this model, the peptide binding pocket abuts the dimerization domain of gp96, which may have implications for the extraordinary stability of peptide-gp96 complexes, and for the faithful relay of peptides to major histocompatibility complex class I molecule for antigen presentation.
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Affiliation(s)
- N A Linderoth
- Laboratory of Molecular Genetics, The Rockefeller University, New York, New York 10021, USA
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Abstract
GRP94 is the ER representative of the HSP90 family of stress-induced proteins. It binds to a limited number of proteins in the secretory pathway, apparently by recognizing advanced folding intermediates or incompletely assembled proteins, GRP94 also binds peptides and can act as a tumor vaccine, delivering the peptides for presentation to T lymphocytes. Here, we review the current data about GRP94 and propose a structural model that integrates the biochemical data and known functions of the protein.
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Affiliation(s)
- Y Argon
- Department of Pathology, University of Chicago, IL 60637, USA
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