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Melnyk A, Lang S, Sicking M, Zimmermann R, Jung M. Co-chaperones of the Human Endoplasmic Reticulum: An Update. Subcell Biochem 2023; 101:247-291. [PMID: 36520310 DOI: 10.1007/978-3-031-14740-1_9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
In mammalian cells, the rough endoplasmic reticulum (ER) plays central roles in the biogenesis of extracellular plus organellar proteins and in various signal transduction pathways. For these reasons, the ER comprises molecular chaperones, which are involved in import, folding, assembly, export, plus degradation of polypeptides, and signal transduction components, such as calcium channels, calcium pumps, and UPR transducers plus adenine nucleotide carriers/exchangers in the ER membrane. The calcium- and ATP-dependent ER lumenal Hsp70, termed immunoglobulin heavy-chain-binding protein or BiP, is the central player in all these activities and involves up to nine different Hsp40-type co-chaperones, i.e., ER membrane integrated as well as ER lumenal J-domain proteins, termed ERj or ERdj proteins, two nucleotide exchange factors or NEFs (Grp170 and Sil1), and NEF-antagonists, such as MANF. Here we summarize the current knowledge on the ER-resident BiP/ERj chaperone network and focus on the interaction of BiP with the polypeptide-conducting and calcium-permeable Sec61 channel of the ER membrane as an example for BiP action and how its functional cycle is linked to ER protein import and various calcium-dependent signal transduction pathways.
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Affiliation(s)
- Armin Melnyk
- Medical Biochemistry & Molecular Biology, Saarland University, Homburg, Germany
| | - Sven Lang
- Medical Biochemistry & Molecular Biology, Saarland University, Homburg, Germany
| | - Mark Sicking
- Medical Biochemistry & Molecular Biology, Saarland University, Homburg, Germany
| | - Richard Zimmermann
- Medical Biochemistry & Molecular Biology, Saarland University, Homburg, Germany.
| | - Martin Jung
- Medical Biochemistry & Molecular Biology, Saarland University, Homburg, Germany
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Multi-Faceted Roles of DNAJB Protein in Cancer Metastasis and Clinical Implications. Int J Mol Sci 2022; 23:ijms232314970. [PMID: 36499297 PMCID: PMC9737691 DOI: 10.3390/ijms232314970] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 11/28/2022] [Accepted: 11/28/2022] [Indexed: 12/02/2022] Open
Abstract
Heat shock proteins (HSPs) are highly conserved molecular chaperones with diverse cellular activities, including protein folding, assembly or disassembly of protein complexes, and maturation process under diverse stress conditions. HSPs also play essential roles in tumorigenesis, metastasis, and therapeutic resistance across cancers. Among them, HSP40s are widely accepted as regulators of HSP70/HSP90 chaperones and an accumulating number of biological functions as molecular chaperones dependent or independent of either of these chaperones. Despite large numbers of HSP40s, little is known about their physiologic roles, specifically in cancer progression. This article summarizes the multi-faceted role of DNAJB proteins as one subclass of the HSP40 family in cancer development and metastasis. Regulation and deregulation of DNAJB proteins at transcriptional, post-transcriptional, and post-translational levels contribute to tumor progression, particularly cancer metastasis. Furthermore, understanding differences in function and regulating mechanism between DNAJB proteins offers a new perspective on tumorigenesis and metastasis to improve therapeutic opportunities for malignant diseases.
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Lang S, Nguyen D, Bhadra P, Jung M, Helms V, Zimmermann R. Signal Peptide Features Determining the Substrate Specificities of Targeting and Translocation Components in Human ER Protein Import. Front Physiol 2022; 13:833540. [PMID: 35899032 PMCID: PMC9309488 DOI: 10.3389/fphys.2022.833540] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2021] [Accepted: 05/17/2022] [Indexed: 12/11/2022] Open
Abstract
In human cells, approximately 30% of all polypeptides enter the secretory pathway at the level of the endoplasmic reticulum (ER). This process involves cleavable amino-terminal signal peptides (SPs) or more or less amino-terminal transmembrane helices (TMHs), which serve as targeting determinants, at the level of the precursor polypeptides and a multitude of cytosolic and ER proteins, which facilitate their ER import. Alone or in combination SPs and TMHs guarantee the initial ER targeting as well as the subsequent membrane integration or translocation. Cytosolic SRP and SR, its receptor in the ER membrane, mediate cotranslational targeting of most nascent precursor polypeptide chains to the polypeptide-conducting Sec61 complex in the ER membrane. Alternatively, fully-synthesized precursor polypeptides and certain nascent precursor polypeptides are targeted to the ER membrane by either the PEX-, SND-, or TRC-pathway. Although these targeting pathways may have overlapping functions, the question arises how relevant this is under cellular conditions and which features of SPs and precursor polypeptides determine preference for a certain pathway. Irrespective of their targeting pathway(s), most precursor polypeptides are integrated into or translocated across the ER membrane via the Sec61 channel. For some precursor polypeptides specific Sec61 interaction partners have to support the gating of the channel to the open state, again raising the question why and when this is the case. Recent progress shed light on the client spectrum and specificities of some auxiliary components, including Sec62/Sec63, TRAM1 protein, and TRAP. To address the question which precursors use a certain pathway or component in intact human cells, i.e., under conditions of fast translation rates and molecular crowding, in the presence of competing precursors, different targeting organelles, and relevant stoichiometries of the involved components, siRNA-mediated depletion of single targeting or transport components in HeLa cells was combined with label-free quantitative proteomics and differential protein abundance analysis. Here, we present a summary of the experimental approach as well as the resulting differential protein abundance analyses and discuss their mechanistic implications in light of the available structural data.
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Affiliation(s)
- Sven Lang
- Medical Biochemistry and Molecular Biology, Saarland University, Homburg, Germany
- *Correspondence: Sven Lang, ; Richard Zimmermann,
| | - Duy Nguyen
- Center for Bioinformatics, Saarland University, Saarbrücken, Germany
| | - Pratiti Bhadra
- Center for Bioinformatics, Saarland University, Saarbrücken, Germany
| | - Martin Jung
- Medical Biochemistry and Molecular Biology, Saarland University, Homburg, Germany
| | - Volkhard Helms
- Center for Bioinformatics, Saarland University, Saarbrücken, Germany
| | - Richard Zimmermann
- Medical Biochemistry and Molecular Biology, Saarland University, Homburg, Germany
- *Correspondence: Sven Lang, ; Richard Zimmermann,
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Schmitt BM, Ampofo E, Stumpf H, Montenarh M, Götz C. The stability of CREB3/Luman is regulated by protein kinase CK2 phosphorylation. Biochem Biophys Res Commun 2020; 523:639-644. [PMID: 31941600 DOI: 10.1016/j.bbrc.2019.12.118] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Accepted: 12/22/2019] [Indexed: 01/11/2023]
Abstract
CREB3 (Luman) is a family member of ER resident transcription factors, which are cleaved upon the induction of ER stress. Their N-terminal fragments shuttle into the nucleus where they regulate the transcription of target genes. Here, we found that human CREB3 is phosphorylated within its transcription activation domain on serine 46 by protein kinase CK2. Further analyses revealed that the phosphorylation of this site does neither affect the cleavage by S1P/S2P proteases, nor the nuclear localisation nor the transcriptional activity of CREB3. However, phosphorylation at serine 46 reduced the stability of CREB3.
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Affiliation(s)
- Beate Maria Schmitt
- Institute for Clinical and Experimental Surgery, Saarland University, Building 65, 66424, Homburg, Germany
| | - Emmanuel Ampofo
- Institute for Clinical and Experimental Surgery, Saarland University, Building 65, 66424, Homburg, Germany
| | - Heike Stumpf
- Medical Biochemistry and Molecular Biology, Saarland University, Building 44, 66424, Homburg, Germany
| | - Mathias Montenarh
- Medical Biochemistry and Molecular Biology, Saarland University, Building 44, 66424, Homburg, Germany
| | - Claudia Götz
- Medical Biochemistry and Molecular Biology, Saarland University, Building 44, 66424, Homburg, Germany.
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Xu Y, Zheng G, Liu G, Yang Q, Yu X. Molecular cloning, characterization of Pomacea canaliculata HSP40 and its expression analysis under temperature change. J Therm Biol 2019; 81:59-65. [PMID: 30975424 DOI: 10.1016/j.jtherbio.2019.02.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 01/13/2019] [Accepted: 02/01/2019] [Indexed: 12/23/2022]
Abstract
Heat shock proteins (HSPs) play important roles in the adaption of Pomacea canaliculata to unsuitable environments. In the present study, a cDNA encoding HSP40 in P. canaliculata (PocaHSP40) was cloned and characterized. The PocaHSP40 cDNA was 1466 bp, containing an ORF of 954 bp encoding 317 amino acids. Bioinformatics analysis showed that PocaHSP40 belonged to type II HSP40s and had four predicted phosphorylation sites. Phylogenetic analysis proved the conservation of HSP40s in mollusks. PocaHSP40 was widely expressed in the gill, digestive gland, kidney, and foot muscle of P. canaliculata. Challenged by different temperatures, the expression of PocaHSP40 was up-regulated under low temperatures but not high temperatures, which was contrary to the expression change of PocaHSP70 under low and high temperatures. These results implied that P. canaliculata evolved different strategies for survival under low temperature and high temperature through the regulation of HSPs.
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Affiliation(s)
- Yipeng Xu
- Zhejiang Provincial Key Laboratory of Biometrology and Inspection & Quarantine, College of Life Sciences, China Jiliang University, 258 Xueyuan Street, Xiasha, Hangzhou 310018, China.
| | - Guowan Zheng
- Zhejiang Provincial Key Laboratory of Biometrology and Inspection & Quarantine, College of Life Sciences, China Jiliang University, 258 Xueyuan Street, Xiasha, Hangzhou 310018, China.
| | - Guangfu Liu
- Zhejiang Provincial Key Laboratory of Biometrology and Inspection & Quarantine, College of Life Sciences, China Jiliang University, 258 Xueyuan Street, Xiasha, Hangzhou 310018, China.
| | - Qianqian Yang
- Zhejiang Provincial Key Laboratory of Biometrology and Inspection & Quarantine, College of Life Sciences, China Jiliang University, 258 Xueyuan Street, Xiasha, Hangzhou 310018, China.
| | - Xiaoping Yu
- Zhejiang Provincial Key Laboratory of Biometrology and Inspection & Quarantine, College of Life Sciences, China Jiliang University, 258 Xueyuan Street, Xiasha, Hangzhou 310018, China.
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Bitirim CV, Tuncay E, Turan B. Demonstration of subcellular migration of CK2α localization from nucleus to sarco(endo)plasmic reticulum in mammalian cardiomyocytes under hyperglycemia. Mol Cell Biochem 2017; 443:25-36. [DOI: 10.1007/s11010-017-3207-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 10/14/2017] [Indexed: 12/16/2022]
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Tuncay E, Bitirim VC, Durak A, Carrat GRJ, Taylor KM, Rutter GA, Turan B. Hyperglycemia-Induced Changes in ZIP7 and ZnT7 Expression Cause Zn 2+ Release From the Sarco(endo)plasmic Reticulum and Mediate ER Stress in the Heart. Diabetes 2017; 66:1346-1358. [PMID: 28232492 DOI: 10.2337/db16-1099] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2016] [Accepted: 02/10/2017] [Indexed: 11/13/2022]
Abstract
Changes in cellular free Zn2+ concentration, including those in the sarco(endo)plasmic reticulum [S(E)R], are primarily coordinated by Zn2+ transporters (ZnTs) whose identity and role in the heart are not well established. We hypothesized that ZIP7 and ZnT7 transport Zn2+ in opposing directions across the S(E)R membrane in cardiomyocytes and that changes in their activity play an important role in the development of ER stress during hyperglycemia. The subcellular S(E)R localization of ZIP7 and ZnT7 was determined in cardiomyocytes and in isolated S(E)R preparations. Markedly increased mRNA and protein levels of ZIP7 were observed in ventricular cardiomyocytes from diabetic rats or high-glucose-treated H9c2 cells while ZnT7 expression was low. In addition, we observed increased ZIP7 phosphorylation in response to high glucose in vivo and in vitro. By using recombinant-targeted Förster resonance energy transfer sensors, we show that hyperglycemia induces a marked redistribution of cellular free Zn2+, increasing cytosolic free Zn2+ and lowering free Zn2+ in the S(E)R. These changes involve alterations in ZIP7 phosphorylation and were suppressed by small interfering RNA-mediated silencing of CK2α. Opposing changes in the expression of ZIP7 and ZnT7 were also observed in hyperglycemia. We conclude that subcellular free Zn2+ redistribution in the hyperglycemic heart, resulting from altered ZIP7 and ZnT7 activity, contributes to cardiac dysfunction in diabetes.
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Affiliation(s)
- Erkan Tuncay
- Department of Biophysics, Faculty of Medicine, Ankara University, Ankara, Turkey
| | - Verda C Bitirim
- Department of Biophysics, Faculty of Medicine, Ankara University, Ankara, Turkey
| | - Aysegul Durak
- Department of Biophysics, Faculty of Medicine, Ankara University, Ankara, Turkey
| | - Gaelle R J Carrat
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Imperial College London, London, U.K
| | - Kathryn M Taylor
- School of Pharmacy and Pharmaceutical Sciences, College of Biomedical and Life Sciences, Cardiff University, Cardiff, U.K
| | - Guy A Rutter
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Imperial College London, London, U.K
| | - Belma Turan
- Department of Biophysics, Faculty of Medicine, Ankara University, Ankara, Turkey
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Abstract
In mammalian cells, the rough endoplasmic reticulum or ER plays a central role in the biogenesis of most extracellular plus many organellar proteins and in cellular calcium homeostasis. Therefore, this organelle comprises molecular chaperones that are involved in import, folding/assembly, export, and degradation of polypeptides in millimolar concentrations. In addition, there are calcium channels/pumps and signal transduction components present in the ER membrane that affect and are affected by these processes. The ER lumenal Hsp70, termed immunoglobulin-heavy chain binding protein or BiP, is the central player in all these activities and involves up to seven different co-chaperones, i.e. ER-membrane integrated as well as ER-lumenal Hsp40s, which are termed ERj or ERdj, and two nucleotide exchange factors.
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Denks K, Vogt A, Sachelaru I, Petriman NA, Kudva R, Koch HG. The Sec translocon mediated protein transport in prokaryotes and eukaryotes. Mol Membr Biol 2014; 31:58-84. [DOI: 10.3109/09687688.2014.907455] [Citation(s) in RCA: 123] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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Intemann J, Saidu NEB, Schwind L, Montenarh M. ER stress signaling in ARPE-19 cells after inhibition of protein kinase CK2 by CX-4945. Cell Signal 2014; 26:1567-75. [PMID: 24686080 DOI: 10.1016/j.cellsig.2014.03.014] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2013] [Revised: 02/26/2014] [Accepted: 03/17/2014] [Indexed: 12/27/2022]
Abstract
Protein kinase CK2 is a critical factor for the survival of cells. It is overexpressed in many cancer cells and provides protection against apoptosis in these cells. Inhibition of CK2 kinase activity in various cancer cells leads to apoptosis, which makes CK2 an attractive target for cancer therapy. Little is, however, known about CK2 inhibition in non-cancerous cells. Using the human retinal pigment epithelial cell line ARPE-19, we analyzed the formation of reactive oxygen species (ROS) and the ER stress signaling pathway after CK2 inhibition with CX-4945. Following CK2 inhibition, we did not find any significant generation of ROS in neither ARPE-19 non-cancer cells nor in HCT116 cancer cells. We found an induction of the ER stress pathway including the activation of eIF2α and ATF4 in both cell types. This activation was sufficient for ARPE-19 cells to cope with the ER stress. Furthermore, in contrast to HCT116 cancer cells, there was no induction of the pro-apoptotic transcription factor CHOP and no induction of apoptosis in the ARPE-19 cells. Overexpression of CHOP, however, induced apoptosis in ARPE-19 cells indicating that this step in the ER stress pathway is abrogated in normal cells compared to cancer cell.
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Affiliation(s)
- Johanna Intemann
- Medical Biochemistry and Molecular Biology, University of the Saarland, Building 44, D-66424 Homburg, Germany
| | | | - Lisa Schwind
- Medical Biochemistry and Molecular Biology, University of the Saarland, Building 44, D-66424 Homburg, Germany
| | - Mathias Montenarh
- Medical Biochemistry and Molecular Biology, University of the Saarland, Building 44, D-66424 Homburg, Germany.
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Kostenko S, Jensen KL, Moens U. Phosphorylation of heat shock protein 40 (Hsp40/DnaJB1) by mitogen-activated protein kinase-activated protein kinase 5 (MK5/PRAK). Int J Biochem Cell Biol 2014; 47:29-37. [DOI: 10.1016/j.biocel.2013.11.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Revised: 10/25/2013] [Accepted: 11/05/2013] [Indexed: 01/08/2023]
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Ampofo E, Welker S, Jung M, Müller L, Greiner M, Zimmermann R, Montenarh M. CK2 phosphorylation of human Sec63 regulates its interaction with Sec62. Biochim Biophys Acta Gen Subj 2012; 1830:2938-45. [PMID: 23287549 DOI: 10.1016/j.bbagen.2012.12.020] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Revised: 12/17/2012] [Accepted: 12/19/2012] [Indexed: 11/29/2022]
Abstract
BACKGROUND Protein kinase CK2 is a pleiotropic enzyme which is ubiquitously expressed in eukaryotic cells. Several years ago CK2 was found to be associated with the mammalian endoplasmic reticulum. So far nothing is known about the function of CK2 at the ER. METHODS CK2 phosphorylation sites in the polypeptide chain of Sec63 were mapped using deletion mutants and a peptide library. Binding of Sec63 to CK2 and to Sec62 was analyzed by pull-down assays and by co-immunoprecipitation RESULTS Sec63 was identified as a novel substrate and binding partner of protein kinase CK2. We identified serine 574, serine 576 and serine 748 as CK2 phosphorylation sites. Phosphorylation of Sec63 by CK2 enhanced its binding to Sec62. CONCLUSIONS Protein kinase CK2 phosphorylation of Sec63 leads to an enhanced binding of Sec63 to Sec62. This complex formation is a prerequisite for a functional ER protein translocon. GENERAL SIGNIFICANCE Thus, our present data indicate a regulatory role of CK2 in the ER protein translocation.
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Affiliation(s)
- Emmanuel Ampofo
- Medizinische Biochemie und Molekularbiologie und Kompetenzzentrum Molekulare Medizin, Universität des Saarlandes, Gebäude 44, 66424 Homburg, Germany
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Manni S, Brancalion A, Tubi LQ, Colpo A, Pavan L, Cabrelle A, Ave E, Zaffino F, Di Maira G, Ruzzene M, Adami F, Zambello R, Pitari MR, Tassone P, Pinna LA, Gurrieri C, Semenzato G, Piazza F. Protein kinase CK2 protects multiple myeloma cells from ER stress-induced apoptosis and from the cytotoxic effect of HSP90 inhibition through regulation of the unfolded protein response. Clin Cancer Res 2012; 18:1888-900. [PMID: 22351691 DOI: 10.1158/1078-0432.ccr-11-1789] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE Protein kinase CK2 promotes multiple myeloma cell growth by regulating critical signaling pathways. CK2 also modulates proper HSP90-dependent client protein folding and maturation by phosphorylating its co-chaperone CDC37. Because the endoplasmic reticulum (ER) stress/unfolded protein response (UPR) is central in myeloma pathogenesis, we tested the hypothesis that the CK2/CDC37/HSP90 axis could be involved in UPR in myeloma cells. EXPERIMENTAL DESIGN We analyzed CK2 activity upon ER stress, the effects of its inactivation on the UPR pathways and on ER stress-induced apoptosis. The consequences of CK2 plus HSP90 inhibition on myeloma cell growth in vitro and in vivo and CK2 regulation of HSP90-triggered UPR were determined. RESULTS CK2 partly localized to the ER and ER stress triggered its kinase activity. CK2 inhibition reduced the levels of the ER stress sensors IRE1α and BIP/GRP78, increased phosphorylation of PERK and EIF2α, and enhanced ER stress-induced apoptosis. Simultaneous inactivation of CK2 and HSP90 resulted in a synergic anti-myeloma effect (combination index = 0.291) and in much stronger alterations of the UPR pathways as compared with the single inhibition of the two molecules. Cytotoxicity from HSP90 and CK2 targeting was present in a myeloma microenvironment model, on plasma cells from patients with myeloma and in an in vivo mouse xenograft model. Mechanistically, CK2 inhibition led to a reduction of IRE1α/HSP90/CDC37 complexes in multiple myeloma cells. CONCLUSIONS Our results place CK2 as a novel regulator of the ER stress/UPR cascades and HSP90 function in myeloma cells and offer the groundwork to design novel combination treatments for this disease.
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Affiliation(s)
- Sabrina Manni
- Department of Medicine, University of Padova, Via Giustiniani 2, Padova 35128, Italy
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