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Papadopoulos N, Nédélec A, Derenne A, Şulea TA, Pecquet C, Chachoua I, Vertenoeil G, Tilmant T, Petrescu AJ, Mazzucchelli G, Iorga BI, Vertommen D, Constantinescu SN. Oncogenic CALR mutant C-terminus mediates dual binding to the thrombopoietin receptor triggering complex dimerization and activation. Nat Commun 2023; 14:1881. [PMID: 37019903 PMCID: PMC10076285 DOI: 10.1038/s41467-023-37277-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Accepted: 03/04/2023] [Indexed: 04/07/2023] Open
Abstract
Calreticulin (CALR) frameshift mutations represent the second cause of myeloproliferative neoplasms (MPN). In healthy cells, CALR transiently and non-specifically interacts with immature N-glycosylated proteins through its N-terminal domain. Conversely, CALR frameshift mutants turn into rogue cytokines by stably and specifically interacting with the Thrombopoietin Receptor (TpoR), inducing its constitutive activation. Here, we identify the basis of the acquired specificity of CALR mutants for TpoR and define the mechanisms by which complex formation triggers TpoR dimerization and activation. Our work reveals that CALR mutant C-terminus unmasks CALR N-terminal domain, rendering it more accessible to bind immature N-glycans on TpoR. We further find that the basic mutant C-terminus is partially α-helical and define how its α-helical segment concomitantly binds acidic patches of TpoR extracellular domain and induces dimerization of both CALR mutant and TpoR. Finally, we propose a model of the tetrameric TpoR-CALR mutant complex and identify potentially targetable sites.
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Affiliation(s)
- Nicolas Papadopoulos
- Ludwig Institute for Cancer Research Brussels, Brussels, Belgium
- Université catholique de Louvain and de Duve Institute, Brussels, Belgium
| | - Audrey Nédélec
- Ludwig Institute for Cancer Research Brussels, Brussels, Belgium
- Université catholique de Louvain and de Duve Institute, Brussels, Belgium
| | - Allison Derenne
- Spectralys Biotech SRL, rue Auguste Piccard 48, 6041, Gosselies, Belgium
| | - Teodor Asvadur Şulea
- Department of Bioinformatics and Structural Biochemistry, Institute of Biochemistry of the Romanian Academy, Splaiul Independentei 296, Bucharest, 060031, Romania
| | - Christian Pecquet
- Ludwig Institute for Cancer Research Brussels, Brussels, Belgium
- Université catholique de Louvain and de Duve Institute, Brussels, Belgium
| | - Ilyas Chachoua
- Ludwig Institute for Cancer Research Brussels, Brussels, Belgium
- Université catholique de Louvain and de Duve Institute, Brussels, Belgium
- Department of Molecular Biology and Genetics, Bilkent University, Ankara, Turkey
| | - Gaëlle Vertenoeil
- Ludwig Institute for Cancer Research Brussels, Brussels, Belgium
- Université catholique de Louvain and de Duve Institute, Brussels, Belgium
| | - Thomas Tilmant
- Mass Spectrometry Laboratory, MolSys Research Unit, Universiy of Liège, 4000, Liège, Belgium
| | - Andrei-Jose Petrescu
- Department of Bioinformatics and Structural Biochemistry, Institute of Biochemistry of the Romanian Academy, Splaiul Independentei 296, Bucharest, 060031, Romania
| | - Gabriel Mazzucchelli
- Mass Spectrometry Laboratory, MolSys Research Unit, Universiy of Liège, 4000, Liège, Belgium
| | - Bogdan I Iorga
- Université Paris-Saclay, CNRS, Institut de Chimie des Substances Naturelles, UPR 2301, Gif-sur-Yvette, France
| | - Didier Vertommen
- Université catholique de Louvain and de Duve Institute, Brussels, Belgium
- de Duve Institute and MASSPROT platform, Brussels, Belgium
| | - Stefan N Constantinescu
- Ludwig Institute for Cancer Research Brussels, Brussels, Belgium.
- Université catholique de Louvain and de Duve Institute, Brussels, Belgium.
- Walloon Excelence in Life Sciences and Biotechnology, WELBIO, avenue Pasteur, 6, 1300, Wavre, Belgium.
- Ludwig Institute for Cancer Research, Nuffield Department of Medicine, Oxford University, Oxford, UK.
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Yan M, Chen Y, Li M, Wu J, Fang Z, Wang J, Liu J. Coprinopsis cinerea Galectin CGL1 Induces Apoptosis and Inhibits Tumor Growth in Colorectal Cancer Cells. Int J Mol Sci 2022; 24:ijms24010235. [PMID: 36613681 PMCID: PMC9820451 DOI: 10.3390/ijms24010235] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 12/15/2022] [Accepted: 12/19/2022] [Indexed: 12/24/2022] Open
Abstract
Mushroom galectins are promising anticancer agents for their low IC50 values against cancer cells in vitro. In this study, two Coprinopsis cinerea galectins, CGL1 and CGL2, were heterologously expressed, and their biochemistry properties and anticancer effects were evaluated. The purified galectins were thermostable at neutral pH conditions. They both existed as tetramers and shared a high affinity towards lactose. CGL1 and CGL2 strongly inhibited the cell viability of many cancer cell lines, including three colorectal cancer cells, in a dose-dependent manner by inducing mitochondria-mediated caspase-dependent apoptosis. Furthermore, CGL1 exhibited higher apoptosis-inducing ability and cytotoxicity than CGL2. In vivo cell viability experiments based on two xenograft mouse models showed that CGL1 had a more substantial inhibitory effect than CGL2 on HCT116 tumor growth (p < 0.0001), whereas only CGL1 inhibited DLD1 tumor growth (p < 0.01). This is the first study to evaluate the anti-colorectal cancer effect of mushroom lectins in vivo, and our results showed that CGL1 is a potent agent for colorectal cancer treatment.
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Affiliation(s)
- Mengli Yan
- School of Life Sciences, Anhui University, Hefei 230601, China
- Anhui Key Laboratory of Modern Biomanufacturing, Hefei 230601, China
- Anhui Provincial Engineering Technology Research Center of Microorganisms and Biocatalysis, Hefei 230601, China
| | - Yaxuan Chen
- School of Life Sciences, Anhui University, Hefei 230601, China
- Anhui Key Laboratory of Modern Biomanufacturing, Hefei 230601, China
- Anhui Provincial Engineering Technology Research Center of Microorganisms and Biocatalysis, Hefei 230601, China
| | - Mengke Li
- School of Life Sciences, Anhui University, Hefei 230601, China
- Anhui Key Laboratory of Modern Biomanufacturing, Hefei 230601, China
- Anhui Provincial Engineering Technology Research Center of Microorganisms and Biocatalysis, Hefei 230601, China
| | - Jiamin Wu
- School of Life Sciences, Anhui University, Hefei 230601, China
| | - Zemin Fang
- School of Life Sciences, Anhui University, Hefei 230601, China
- Anhui Key Laboratory of Modern Biomanufacturing, Hefei 230601, China
- Anhui Provincial Engineering Technology Research Center of Microorganisms and Biocatalysis, Hefei 230601, China
| | - Junjun Wang
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei 230031, China
- Correspondence: (J.W.); (J.L.)
| | - Juanjuan Liu
- School of Life Sciences, Anhui University, Hefei 230601, China
- Anhui Key Laboratory of Modern Biomanufacturing, Hefei 230601, China
- Anhui Provincial Engineering Technology Research Center of Microorganisms and Biocatalysis, Hefei 230601, China
- Correspondence: (J.W.); (J.L.)
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3
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Hematoxylin binds to mutant calreticulin and disrupts its abnormal interaction with thrombopoietin receptor. Blood 2021; 137:1920-1931. [PMID: 33202418 DOI: 10.1182/blood.2020006264] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 11/05/2020] [Indexed: 12/21/2022] Open
Abstract
Somatic mutations of calreticulin (CALR) have been identified as a main disease driver of myeloproliferative neoplasms, suggesting that development of drugs targeting mutant CALR is of great significance. Site-directed mutagenesis in the N-glycan binding domain (GBD) abolishes the ability of mutant CALR to oncogenically activate the thrombopoietin receptor (MPL). We therefore hypothesized that a small molecule targeting the GBD might inhibit the oncogenicity of the mutant CALR. Using an in silico molecular docking study, we identified candidate binders to the GBD of CALR. Further experimental validation of the hits identified a group of catechols inducing a selective growth inhibitory effect on cells that depend on oncogenic CALR for survival and proliferation. Apoptosis-inducing effects by the compound were significantly higher in the CALR-mutated cells than in CALR wild-type cells. Additionally, knockout or C-terminal truncation of CALR eliminated drug hypersensitivity in CALR-mutated cells. We experimentally confirmed the direct binding of the selected compound to CALR, disruption of the mutant CALR-MPL interaction, inhibition of the JAK2-STAT5 pathway, and reduction at the intracellular level of mutant CALR upon drug treatment. Our data indicate that small molecules targeting the GBD of CALR can selectively kill CALR-mutated cells by disrupting the CALR-MPL interaction and inhibiting oncogenic signaling.
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Doğan C, Hänniger S, Heckel DG, Coutu C, Hegedus DD, Crubaugh L, Groves RL, Bayram Ş, Toprak U. Two calcium-binding chaperones from the fat body of the Colorado potato beetle, Leptinotarsa decemlineata (Coleoptera: Chrysomelidae) involved in diapause. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2021; 106:e21755. [PMID: 33118236 DOI: 10.1002/arch.21755] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 10/13/2020] [Accepted: 10/19/2020] [Indexed: 06/11/2023]
Abstract
Molecular chaperones are crucial for the correct folding of newly synthesized polypeptides, in particular, under stress conditions. Various studies have revealed the involvement of molecular chaperones, such as heat shock proteins, in diapause maintenance and starvation; however, the role of other chaperones in diapause and starvation relatively is unknown. In the current study, we identified two lectin-type chaperones with calcium affinity, a calreticulin (LdCrT) and a calnexin (LdCnX), that were present in the fat body of the Colorado potato beetle, Leptinotarsa decemlineata (Coleoptera: Chrysomelidae) during diapause. Both proteins possessed an N-globular domain, a P-arm domain, and a highly charged C-terminal domain, while an additional transmembrane domain was present in LdCnX. Phylogenetic analysis revealed distinction at the order level. Both genes were expressed in multiple tissues in larval and adult stages, and constitutively throughout development, though a starvation response was detected only for LdCrT. In females, diapause-related expression analysis in the whole body revealed an upregulation of both genes by post-diapause, but a downregulation by diapause only for LdCrT. By contrast, males revealed no alteration in their diapause-related expression pattern in the entire body for both genes. Fat body-specific expression analysis of both genes in relation to diapause revealed the same expression pattern with no alteration in females and downregulation in males by post-diapause. This study suggests that calcium-binding chaperones play similar and possibly gender-specific roles during diapause.
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Affiliation(s)
- Cansu Doğan
- Molecular Entomology Lab, Department of Plant Protection, Faculty of Agriculture, Ankara University, Ankara, Turkey
- Department of Entomology, Max Planck Institute for Chemical Ecology, Jena, Germany
- Agriculture and Agri-Food Canada, Saskatoon Research Centre, Saskatoon, Saskatchewan, Canada
- Department of Entomology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Sabine Hänniger
- Department of Entomology, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - David G Heckel
- Department of Entomology, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Cathy Coutu
- Agriculture and Agri-Food Canada, Saskatoon Research Centre, Saskatoon, Saskatchewan, Canada
| | - Dwayne D Hegedus
- Agriculture and Agri-Food Canada, Saskatoon Research Centre, Saskatoon, Saskatchewan, Canada
| | - Linda Crubaugh
- Department of Entomology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Russell L Groves
- Department of Entomology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Şerife Bayram
- Molecular Entomology Lab, Department of Plant Protection, Faculty of Agriculture, Ankara University, Ankara, Turkey
| | - Umut Toprak
- Molecular Entomology Lab, Department of Plant Protection, Faculty of Agriculture, Ankara University, Ankara, Turkey
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5
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Yang H, Ahmad ZA, Song Y. Molecular insight for the role of key residues of calreticulin in its binding activities: A computational study. Comput Biol Chem 2020; 85:107228. [DOI: 10.1016/j.compbiolchem.2020.107228] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 01/28/2020] [Accepted: 02/01/2020] [Indexed: 12/26/2022]
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Abstract
The site of protein folding and maturation for the majority of proteins that are secreted, localized to the plasma membrane or targeted to endomembrane compartments is the endoplasmic reticulum (ER). It is essential that proteins targeted to the ER are properly folded in order to carry out their function, as well as maintain protein homeostasis, as accumulation of misfolded proteins could lead to the formation of cytotoxic aggregates. Because protein folding is an error-prone process, the ER contains protein quality control networks that act to optimize proper folding and trafficking of client proteins. If a protein is unable to reach its native state, it is targeted for ER retention and subsequent degradation. The protein quality control networks of the ER that oversee this evaluation or interrogation process that decides the fate of maturing nascent chains is comprised of three general types of families: the classical chaperones, the carbohydrate-dependent system, and the thiol-dependent system. The cooperative action of these families promotes protein quality control and protein homeostasis in the ER. This review will describe the families of the ER protein quality control network and discuss the functions of individual members.
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7
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Calreticulin mutants as oncogenic rogue chaperones for TpoR and traffic-defective pathogenic TpoR mutants. Blood 2019; 133:2669-2681. [PMID: 30902807 DOI: 10.1182/blood-2018-09-874578] [Citation(s) in RCA: 71] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Accepted: 03/12/2019] [Indexed: 01/22/2023] Open
Abstract
Calreticulin (CALR) +1 frameshift mutations in exon 9 are prevalent in myeloproliferative neoplasms. Mutant CALRs possess a new C-terminal sequence rich in positively charged amino acids, leading to activation of the thrombopoietin receptor (TpoR/MPL). We show that the new sequence endows the mutant CALR with rogue chaperone activity, stabilizing a dimeric state and transporting TpoR and mutants thereof to the cell surface in states that would not pass quality control; this function is absolutely required for oncogenic transformation. Mutant CALRs determine traffic via the secretory pathway of partially immature TpoR, as they protect N117-linked glycans from further processing in the Golgi apparatus. A number of engineered or disease-associated TpoRs such as TpoR/MPL R102P, which causes congenital thrombocytopenia, are rescued for traffic and function by mutant CALRs, which can also overcome endoplasmic reticulum retention signals on TpoR. In addition to requiring N-glycosylation of TpoR, mutant CALRs require a hydrophobic patch located in the extracellular domain of TpoR to induce TpoR thermal stability and initial intracellular activation, whereas full activation requires cell surface localization of TpoR. Thus, mutant CALRs are rogue chaperones for TpoR and traffic-defective TpoR mutants, a function required for the oncogenic effects.
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Glinschert A, Oscarson S. Synthesis of four (4″-, 2″-, 2′-, and 6-) monodeoxy analogs of the trisaccharide α-d-Glcp-(1→3)-α-d-Manp-(1→2)-α-d-ManpOMe recognized by Calreticulin/Calnexin. Carbohydr Res 2015; 414:65-71. [DOI: 10.1016/j.carres.2015.07.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Revised: 06/17/2015] [Accepted: 07/10/2015] [Indexed: 10/23/2022]
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9
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Matsunaga R, Abe R, Ishii D, Watanabe SI, Kiyoshi M, Nöcker B, Tsuchiya M, Tsumoto K. Bidirectional binding property of high glycine-tyrosine keratin-associated protein contributes to the mechanical strength and shape of hair. J Struct Biol 2013; 183:484-494. [PMID: 23791804 DOI: 10.1016/j.jsb.2013.06.005] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Revised: 05/29/2013] [Accepted: 06/04/2013] [Indexed: 11/30/2022]
Abstract
Since their first finding in wool 50years ago, keratin-associated proteins (KAPs), which are classified into three groups; high sulfur (HS) KAPs, ultra high sulfur (UHS) KAPs, and high glycine-tyrosine (HGT) KAPs, have been the target of curiosity for scientists due to their characteristic amino acid sequences. While HS and UHS KAPs are known to function in disulfide bond crosslinking, the function of HGT KAPs remains unknown. To clarify the function as well as the binding partners of HGT KAPs, we prepared KAP8.1 and other KAP family proteins, the trichocyte intermediate filament proteins (IFP) K85 and K35, the head domain of K85, and the C subdomain of desmoplakin C-terminus (DPCT-C) and investigated the interactions between them in vitro. Western blot analysis and isothermal titration calorimetry (ITC) indicate that KAP8.1 binds to the head domain of K85, which is helically aligned around the axis of the intermediate filament (IF). From these results and transmission electron microscopy (TEM) observations of bundled filament complex in vitro, we propose that the helical arrangement of IFs found in the orthocortex, which is uniquely distributed on the convex fiber side of the hair, is regulated by KAP8.1. Structure-dependent binding of DPCT-C to trichocyte IFP was confirmed by Western blotting, ITC, and circular dichroism. Moreover, DPCT-C also binds to some HGT KAPs. It is probable that such bidirectional binding property of HGT KAPs contribute to the mechanical robustness of hair.
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Affiliation(s)
- Ryo Matsunaga
- Medical Proteomics Laboratory, Institute of Medical Science, The University of Tokyo, 4-6-1, Shirokanedai, Minato-ku, Tokyo 108-8639, Japan
| | - Ryota Abe
- Medical Proteomics Laboratory, Institute of Medical Science, The University of Tokyo, 4-6-1, Shirokanedai, Minato-ku, Tokyo 108-8639, Japan
| | - Daisuke Ishii
- Beauty Research, R&D, Kao Corporation, 2-1-3, Bunka, Sumida-ku, Tokyo 131-8501, Japan
| | - Shun-Ichi Watanabe
- Beauty Research, R&D, Kao Corporation, 2-1-3, Bunka, Sumida-ku, Tokyo 131-8501, Japan
| | - Masato Kiyoshi
- Medical Proteomics Laboratory, Institute of Medical Science, The University of Tokyo, 4-6-1, Shirokanedai, Minato-ku, Tokyo 108-8639, Japan
| | - Bernd Nöcker
- Beauty Research, R&D, Kao Corporation, 2-1-3, Bunka, Sumida-ku, Tokyo 131-8501, Japan
| | - Masaru Tsuchiya
- Beauty Research, R&D, Kao Corporation, 2-1-3, Bunka, Sumida-ku, Tokyo 131-8501, Japan.
| | - Kouhei Tsumoto
- Medical Proteomics Laboratory, Institute of Medical Science, The University of Tokyo, 4-6-1, Shirokanedai, Minato-ku, Tokyo 108-8639, Japan.
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Liu Y, Li J. An in vivo investigation of amino acid residues critical for the lectin function of Arabidopsis calreticulin 3. MOLECULAR PLANT 2013; 6:985-7. [PMID: 23288863 PMCID: PMC3660953 DOI: 10.1093/mp/sss163] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Accepted: 12/26/2012] [Indexed: 05/26/2023]
Affiliation(s)
| | - Jianming Li
- To whom correspondence should be addressed. E-mail , tel. +1 734–763–4253, fax +1 734–647–0884
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11
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Liu Y, Li J. A conserved basic residue cluster is essential for the protein quality control function of the Arabidopsis calreticulin 3. PLANT SIGNALING & BEHAVIOR 2013; 8:e23864. [PMID: 23425854 PMCID: PMC3956487 DOI: 10.4161/psb.23864] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Calreticulin (CRT) is a highly conserved chaperone-like lectin that regulates Ca(2+) homeostasis and participates in protein quality control in the endoplasmic reticulum (ER). Most of our CRT knowledge came from mammalian studies, but our understanding of plant CRTs is limited. Many plants contain more than two CRTs that form two distinct groups: CRT1/CRT2 and CRT3. Previous studies on plant CRTs were focused on their Ca(2+)-binding function, but recent studies revealed a crucial role for the Arabidopsis CRT3 in ER retention of a mutant brassinosteroid receptor, brassinosteroid-insensitive 1-9 (bri1-9) and in complete folding of a plant immunity receptor EF-Tu Receptor (EFR). However, little is known about the molecular basis of the functional specification of the CRTs. We have recently shown that the C-terminal domain of CRT3, which is rich in basic residues, is essential for retaining bri1-9 in the ER; however, its role in assisting EFR folding has not been studied. Here, we used an insertional mutant of CRT3, ebs2-8 (EMS mutagenized bri1 suppressor 2-8), in the bri1-9 background as a genetic system to investigate the functional importance of two basic residue clusters in the CRT3's C-terminal domain. Complementation experiments of ebs2-8 bri1-9 with mutant CRT3(M) transgenes showed that a highly conserved basic tetrapeptide Arg(392)Arg (393)Arg(394)Lys(395) is essential but a less conserved basic tetrapeptide Arg(401)Arg(402)Arg(403)Arg(404) is dispensable for the quality control function of CRT3 that retains bri1-9 in the ER and facilitates the complete folding of EFR.
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12
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Hariprasad G, Kumar M, Rani K, Kaur P, Srinivasan A. Aminoglycoside induced nephrotoxicity: molecular modeling studies of calreticulin-gentamicin complex. J Mol Model 2011; 18:2645-52. [DOI: 10.1007/s00894-011-1289-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2011] [Accepted: 10/20/2011] [Indexed: 12/11/2022]
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13
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Kozlov G, Pocanschi CL, Rosenauer A, Bastos-Aristizabal S, Gorelik A, Williams DB, Gehring K. Structural basis of carbohydrate recognition by calreticulin. J Biol Chem 2010; 285:38612-20. [PMID: 20880849 PMCID: PMC2992293 DOI: 10.1074/jbc.m110.168294] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2010] [Revised: 09/06/2010] [Indexed: 11/06/2022] Open
Abstract
The calnexin cycle is a process by which glycosylated proteins are subjected to folding cycles in the endoplasmic reticulum lumen via binding to the membrane protein calnexin (CNX) or to its soluble homolog calreticulin (CRT). CNX and CRT specifically recognize monoglucosylated Glc(1)Man(9)GlcNAc(2) glycans, but the structural determinants underlying this specificity are unknown. Here, we report a 1.95-Å crystal structure of the CRT lectin domain in complex with the tetrasaccharide α-Glc-(1→3)-α-Man-(1→2)-α-Man-(1→2)-Man. The tetrasaccharide binds to a long channel on CRT formed by a concave β-sheet. All four sugar moieties are engaged in the protein binding via an extensive network of hydrogen bonds and hydrophobic contacts. The structure explains the requirement for glucose at the nonreducing end of the carbohydrate; the oxygen O(2) of glucose perfectly fits to a pocket formed by CRT side chains while forming direct hydrogen bonds with the carbonyl of Gly(124) and the side chain of Lys(111). The structure also explains a requirement for the Cys(105)-Cys(137) disulfide bond in CRT/CNX for efficient carbohydrate binding. The Cys(105)-Cys(137) disulfide bond is involved in intimate contacts with the third and fourth sugar moieties of the Glc(1)Man(3) tetrasaccharide. Finally, the structure rationalizes previous mutagenesis of CRT and lays a structural groundwork for future studies of the role of CNX/CRT in diverse biological pathways.
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Affiliation(s)
- Guennadi Kozlov
- From the Department of Biochemistry, Groupe de Recherche Axé sur la Structure des Protéines, McGill University, Montréal, Québec H3G 0B1, Canada and
| | - Cosmin L. Pocanschi
- the Departments of Biochemistry and Immunology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Angelika Rosenauer
- From the Department of Biochemistry, Groupe de Recherche Axé sur la Structure des Protéines, McGill University, Montréal, Québec H3G 0B1, Canada and
| | - Sara Bastos-Aristizabal
- From the Department of Biochemistry, Groupe de Recherche Axé sur la Structure des Protéines, McGill University, Montréal, Québec H3G 0B1, Canada and
| | - Alexei Gorelik
- From the Department of Biochemistry, Groupe de Recherche Axé sur la Structure des Protéines, McGill University, Montréal, Québec H3G 0B1, Canada and
| | - David B. Williams
- the Departments of Biochemistry and Immunology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Kalle Gehring
- From the Department of Biochemistry, Groupe de Recherche Axé sur la Structure des Protéines, McGill University, Montréal, Québec H3G 0B1, Canada and
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Elumalai P, Rajasekaran M, Liu HL, Chen C. Investigation of cation-π interactions in sugar-binding proteins. PROTOPLASMA 2010; 247:13-24. [PMID: 20379838 DOI: 10.1007/s00709-010-0132-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2009] [Accepted: 03/02/2010] [Indexed: 05/29/2023]
Abstract
Cation-π interaction is a non-covalent binding force that plays a significant role in protein stability and drug-receptor interactions. In this work, we have investigated the structural role of cation-π interactions in sugar-binding proteins (SBPs). We observed 212 cation-π interactions in 53 proteins out of 59 SBPs in dataset. There is an average one energetically significant cation-π interaction for every 66 residues in SBPs. In addition, Arg is highly preferred to form cation-π interactions, and the average energy of Arg-Trp is high among six pairs. Long-range interactions are predominant in the analyzed cation-π interactions. Comparatively, all interaction pairs favor to accommodate in strand conformations. The analysis of solvent accessible area indicates that most of the aromatic residues are found on buried or partially buried whereas cationic residues were found mostly on the exposed regions of protein. The cation-π interactions forming residues were found that around 43% of cation-π residues had highly conserved with the conservation score ≥6. Almost cationic and π-residues equally share in the stabilization center. Sugar-binding site analysis in available complexes showed that the frequency of Trp and Arg is high, suggesting the potential role of these two residues in the interactions between proteins and sugar molecules. Our observations in this study could help to further understand the structural stability of SBPs.
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Affiliation(s)
- Pavadai Elumalai
- Graduate Institute of Biotechnology, National Taipei University of Technology, 1 Sec. 3 ZhongXiao E. Rd., Taipei, Taiwan
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15
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Del Cid N, Jeffery E, Rizvi SM, Stamper E, Peters LR, Brown WC, Provoda C, Raghavan M. Modes of calreticulin recruitment to the major histocompatibility complex class I assembly pathway. J Biol Chem 2009; 285:4520-35. [PMID: 19959473 DOI: 10.1074/jbc.m109.085407] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Major histocompatibility complex (MHC) class I molecules are ligands for T-cell receptors of CD8(+) T cells and inhibitory receptors of natural killer cells. Assembly of the heavy chain, light chain, and peptide components of MHC class I molecules occurs in the endoplasmic reticulum (ER). Specific assembly factors and generic ER chaperones, collectively called the MHC class I peptide loading complex (PLC), are required for MHC class I assembly. Calreticulin has an important role within the PLC and induces MHC class I cell surface expression, but the interactions and mechanisms involved are incompletely understood. We show that interactions with the thiol oxidoreductase ERp57 and substrate glycans are important for the recruitment of calreticulin into the PLC and for its functional activities in MHC class I assembly. The glycan and ERp57 binding sites of calreticulin contribute directly or indirectly to complexes between calreticulin and the MHC class I assembly factor tapasin and are important for maintaining steady-state levels of both tapasin and MHC class I heavy chains. A number of destabilizing conditions and mutations induce generic polypeptide binding sites on calreticulin and contribute to calreticulin-mediated suppression of misfolded protein aggregation in vitro. We show that generic polypeptide binding sites per se are insufficient for stable recruitment of calreticulin to PLC substrates in cells. However, such binding sites could contribute to substrate stabilization in a step that follows the glycan and ERp57-dependent recruitment of calreticulin to the PLC.
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Affiliation(s)
- Natasha Del Cid
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan 48109, USA
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Michalak M, Groenendyk J, Szabo E, Gold L, Opas M. Calreticulin, a multi-process calcium-buffering chaperone of the endoplasmic reticulum. Biochem J 2009; 417:651-666. [DOI: 10.1042/bj20081847] [Citation(s) in RCA: 522] [Impact Index Per Article: 34.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023]
Abstract
Calreticulin is an ER (endoplasmic reticulum) luminal Ca2+-buffering chaperone. The protein is involved in regulation of intracellular Ca2+ homoeostasis and ER Ca2+ capacity. The protein impacts on store-operated Ca2+ influx and influences Ca2+-dependent transcriptional pathways during embryonic development. Calreticulin is also involved in the folding of newly synthesized proteins and glycoproteins and, together with calnexin (an integral ER membrane chaperone similar to calreticulin) and ERp57 [ER protein of 57 kDa; a PDI (protein disulfide-isomerase)-like ER-resident protein], constitutes the ‘calreticulin/calnexin cycle’ that is responsible for folding and quality control of newly synthesized glycoproteins. In recent years, calreticulin has been implicated to play a role in many biological systems, including functions inside and outside the ER, indicating that the protein is a multi-process molecule. Regulation of Ca2+ homoeostasis and ER Ca2+ buffering by calreticulin might be the key to explain its multi-process property.
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Affiliation(s)
- Marek Michalak
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada, T6G 2H7
| | - Jody Groenendyk
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada, T6G 2H7
| | - Eva Szabo
- Laboratory of Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada, M5S 1A8
| | - Leslie I. Gold
- Departments of Medicine and Pathology, New York University School of Medicine, New York, NY 10016, U.S.A
| | - Michal Opas
- Laboratory of Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada, M5S 1A8
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Defining substrate interactions with calreticulin: an isothermal titration calorimetric study. Glycoconj J 2008; 25:797-802. [DOI: 10.1007/s10719-008-9151-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2008] [Revised: 05/19/2008] [Accepted: 05/20/2008] [Indexed: 11/26/2022]
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18
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Ireland BS, Brockmeier U, Howe CM, Elliott T, Williams DB. Lectin-deficient calreticulin retains full functionality as a chaperone for class I histocompatibility molecules. Mol Biol Cell 2008; 19:2413-23. [PMID: 18337472 DOI: 10.1091/mbc.e07-10-1055] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Calreticulin is a molecular chaperone of the endoplasmic reticulum that uses both a lectin site specific for Glc(1)Man(5-9)GlcNAc(2) oligosaccharides and a polypeptide binding site to interact with nascent glycoproteins. The latter mode of substrate recognition is controversial. To examine the relevance of polypeptide binding to protein folding in living cells, we prepared lectin-deficient mutants of calreticulin and examined their abilities to support the assembly and quality control of mouse class I histocompatibility molecules. In cells lacking calreticulin, class I molecules exhibit inefficient loading of peptide ligands, reduced cell surface expression and aberrantly rapid export from the endoplasmic reticulum. Remarkably, expression of calreticulin mutants that are completely devoid of lectin function fully complemented all of the class I biosynthetic defects. We conclude that calreticulin can use nonlectin-based modes of substrate interaction to effect its chaperone and quality control functions on class I molecules in living cells. Furthermore, pulse-chase coimmunoisolation experiments revealed that lectin-deficient calreticulin bound to a similar spectrum of client proteins as wild-type calreticulin and dissociated with similar kinetics, suggesting that lectin-independent interactions are commonplace in cells and that they seem to be regulated during client protein maturation.
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Affiliation(s)
- Breanna S Ireland
- Department of Biochemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
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Okhrimenko O, Jelesarov I. A survey of the year 2006 literature on applications of isothermal titration calorimetry. J Mol Recognit 2008; 21:1-19. [DOI: 10.1002/jmr.859] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Tatami A, Hon YS, Matsuo I, Takatani M, Koshino H, Ito Y. Analyses of carbohydrate binding property of lectin-chaperone calreticulin. Biochem Biophys Res Commun 2007; 364:332-7. [DOI: 10.1016/j.bbrc.2007.10.008] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2007] [Accepted: 10/03/2007] [Indexed: 10/22/2022]
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