151
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Vauthier V, Housset C, Falguières T. Targeted pharmacotherapies for defective ABC transporters. Biochem Pharmacol 2017; 136:1-11. [DOI: 10.1016/j.bcp.2017.02.020] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Accepted: 02/23/2017] [Indexed: 02/07/2023]
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152
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Hu W, Yu X, Liu Z, Sun Y, Chen X, Yang X, Li X, Lam WK, Duan Y, Cao X, Steller H, Liu K, Huang P. The complex of TRIP-Br1 and XIAP ubiquitinates and degrades multiple adenylyl cyclase isoforms. eLife 2017; 6. [PMID: 28656888 PMCID: PMC5503512 DOI: 10.7554/elife.28021] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2017] [Accepted: 06/28/2017] [Indexed: 12/03/2022] Open
Abstract
Adenylyl cyclases (ACs) generate cAMP, a second messenger of utmost importance that regulates a vast array of biological processes in all kingdoms of life. However, almost nothing is known about how AC activity is regulated through protein degradation mediated by ubiquitination or other mechanisms. Here, we show that transcriptional regulator interacting with the PHD-bromodomain 1 (TRIP-Br1, Sertad1), a newly identified protein with poorly characterized functions, acts as an adaptor that bridges the interaction of multiple AC isoforms with X-linked inhibitor of apoptosis protein (XIAP), a RING-domain E3 ubiquitin ligase. XIAP ubiquitinates a highly conserved Lys residue in AC isoforms and thereby accelerates the endocytosis and degradation of multiple AC isoforms in human cell lines and mice. XIAP/TRIP-Br1-mediated degradation of ACs forms part of a negative-feedback loop that controls the homeostasis of cAMP signaling in mice. Our findings reveal a previously unrecognized mechanism for degrading multiple AC isoforms and modulating the homeostasis of cAMP signaling. DOI:http://dx.doi.org/10.7554/eLife.28021.001
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Affiliation(s)
- Wenbao Hu
- Division of Life Science, Hong Kong University of Science and Technology, Hong Kong, China
| | - Xiaojie Yu
- Division of Life Science, Hong Kong University of Science and Technology, Hong Kong, China
| | - Zhengzhao Liu
- Division of Life Science, Hong Kong University of Science and Technology, Hong Kong, China
| | - Ying Sun
- Division of Life Science, Hong Kong University of Science and Technology, Hong Kong, China
| | - Xibing Chen
- Division of Life Science, Hong Kong University of Science and Technology, Hong Kong, China
| | - Xin Yang
- Division of Life Science, Hong Kong University of Science and Technology, Hong Kong, China
| | - Xiaofen Li
- Division of Biomedical Engineering, Hong Kong University of Science and Technology, Hong Kong, China
| | - Wai Kwan Lam
- Division of Life Science, Hong Kong University of Science and Technology, Hong Kong, China
| | - Yuanyuan Duan
- Division of Biomedical Engineering, Hong Kong University of Science and Technology, Hong Kong, China
| | - Xu Cao
- Division of Life Science, Hong Kong University of Science and Technology, Hong Kong, China
| | - Hermann Steller
- Strang Laboratory of Apoptosis and Cancer Biology, Howard Hughes Medical Institute, The Rockefeller University, New York, United States
| | - Kai Liu
- Division of Life Science, Hong Kong University of Science and Technology, Hong Kong, China.,State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
| | - Pingbo Huang
- Division of Life Science, Hong Kong University of Science and Technology, Hong Kong, China.,Division of Biomedical Engineering, Hong Kong University of Science and Technology, Hong Kong, China.,State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China
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153
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The Ubiquitin Ligase CHIP Integrates Proteostasis and Aging by Regulation of Insulin Receptor Turnover. Cell 2017; 169:470-482.e13. [PMID: 28431247 PMCID: PMC5406386 DOI: 10.1016/j.cell.2017.04.003] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Revised: 02/21/2017] [Accepted: 04/03/2017] [Indexed: 12/13/2022]
Abstract
Aging is attended by a progressive decline in protein homeostasis (proteostasis), aggravating the risk for protein aggregation diseases. To understand the coordination between proteome imbalance and longevity, we addressed the mechanistic role of the quality-control ubiquitin ligase CHIP, which is a key regulator of proteostasis. We observed that CHIP deficiency leads to increased levels of the insulin receptor (INSR) and reduced lifespan of worms and flies. The membrane-bound INSR regulates the insulin and IGF1 signaling (IIS) pathway and thereby defines metabolism and aging. INSR is a direct target of CHIP, which triggers receptor monoubiquitylation and endocytic-lysosomal turnover to promote longevity. However, upon proteotoxic stress conditions and during aging, CHIP is recruited toward disposal of misfolded proteins, reducing its capacity to degrade the INSR. Our study indicates a competitive relationship between proteostasis and longevity regulation through CHIP-assisted proteolysis, providing a mechanistic concept for understanding the impact of proteome imbalance on aging. The ubiquitin ligase CHIP triggers insulin receptor turnover Insulin receptor level is linked to insulin and IGF1 signaling and longevity Engagement of CHIP in protein quality control limits insulin receptor degradation Proteotoxic stress aggravates insulin receptor stability, drives aging, and shortens lifespan
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154
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Steinberger B, Yu H, Brodmann T, Milovanovic D, Reichart U, Besenfelder U, Artemenko K, Razzazi-Fazeli E, Brem G, Mayrhofer C. Semen modulated secretory activity of oviductal epithelial cells is linked to cellular proteostasis network remodeling: Proteomic insights into the early phase of interaction in the oviduct in vivo. J Proteomics 2017; 163:14-27. [DOI: 10.1016/j.jprot.2017.05.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Revised: 04/21/2017] [Accepted: 05/04/2017] [Indexed: 11/16/2022]
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155
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Kirchner S, Cai Z, Rauscher R, Kastelic N, Anding M, Czech A, Kleizen B, Ostedgaard LS, Braakman I, Sheppard DN, Ignatova Z. Alteration of protein function by a silent polymorphism linked to tRNA abundance. PLoS Biol 2017; 15:e2000779. [PMID: 28510592 PMCID: PMC5433685 DOI: 10.1371/journal.pbio.2000779] [Citation(s) in RCA: 92] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 04/13/2017] [Indexed: 01/22/2023] Open
Abstract
Synonymous single nucleotide polymorphisms (sSNPs) are considered neutral for protein function, as by definition they exchange only codons, not amino acids. We identified an sSNP that modifies the local translation speed of the cystic fibrosis transmembrane conductance regulator (CFTR), leading to detrimental changes to protein stability and function. This sSNP introduces a codon pairing to a low-abundance tRNA that is particularly rare in human bronchial epithelia, but not in other human tissues, suggesting tissue-specific effects of this sSNP. Up-regulation of the tRNA cognate to the mutated codon counteracts the effects of the sSNP and rescues protein conformation and function. Our results highlight the wide-ranging impact of sSNPs, which invert the programmed local speed of mRNA translation and provide direct evidence for the central role of cellular tRNA levels in mediating the actions of sSNPs in a tissue-specific manner. Synonymous single nucleotide polymorphisms (sSNPs) occur at high frequency in the human genome and are associated with ~50 diseases in humans; the responsible molecular mechanisms remain enigmatic. Here, we investigate the impact of the common sSNP, T2562G, on cystic fibrosis transmembrane conductance regulator (CFTR). Although this sSNP, by itself, does not cause cystic fibrosis (CF), it is prevalent in patients with CFTR-related disorders. T2562G sSNP modifies the local translation speed at the Thr854 codon, leading to changes in CFTR stability and channel function. This sSNP introduces a codon pairing to a low-abundance tRNA, which is particularly rare in human bronchial epithelia, but not in other human tissues, suggesting a tissue-specific effect of this sSNP. Enhancement of the cellular concentration of the tRNA cognate to the mutant ACG codon rescues the stability and conduction defects of T2562G-CFTR. These findings reveal an unanticipated mechanism—inverting the programmed local speed of mRNA translation in a tRNA-dependent manner—for sSNP-associated diseases.
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Affiliation(s)
- Sebastian Kirchner
- Biochemistry, Institute of Biochemistry and Biology, University of Potsdam, Potsdam, Germany
| | - Zhiwei Cai
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
| | - Robert Rauscher
- Institute for Biochemistry and Molecular Biology, Department of Chemistry, University of Hamburg, Hamburg, Germany
| | - Nicolai Kastelic
- Biochemistry, Institute of Biochemistry and Biology, University of Potsdam, Potsdam, Germany
| | - Melanie Anding
- Biochemistry, Institute of Biochemistry and Biology, University of Potsdam, Potsdam, Germany
| | - Andreas Czech
- Institute for Biochemistry and Molecular Biology, Department of Chemistry, University of Hamburg, Hamburg, Germany
| | - Bertrand Kleizen
- Cellular Protein Chemistry, Department of Chemistry, Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, The Netherlands
| | - Lynda S. Ostedgaard
- Department of Internal Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Ineke Braakman
- Cellular Protein Chemistry, Department of Chemistry, Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, The Netherlands
| | - David N. Sheppard
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
- * E-mail: (ZI); (DNS)
| | - Zoya Ignatova
- Biochemistry, Institute of Biochemistry and Biology, University of Potsdam, Potsdam, Germany
- Institute for Biochemistry and Molecular Biology, Department of Chemistry, University of Hamburg, Hamburg, Germany
- * E-mail: (ZI); (DNS)
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156
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Lopes-Pacheco M, Boinot C, Sabirzhanova I, Rapino D, Cebotaru L. Combination of Correctors Rescues CFTR Transmembrane-Domain Mutants by Mitigating their Interactions with Proteostasis. Cell Physiol Biochem 2017; 41:2194-2210. [PMID: 28448979 PMCID: PMC7082854 DOI: 10.1159/000475578] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Accepted: 03/15/2017] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND/AIMS Premature degradation of mutated cystic fibrosis transmembrane conductance regulator (CFTR) protein causes cystic fibrosis (CF), the commonest Mendelian disease in Caucasians. Despite recent advances in precision medicines for CF patients, many CFTR mutants have not been characterized and the effects of these new therapeutic approaches are still unclear for those mutants. METHODS Cells transfected or stably expressing four CFTR transmembrane-domain mutants (G85E, E92K, L1077P, and M1101K) were used to: 1) characterize the mutants according to their protein expression, thermal sensitivity, and degradation pathways; 2) evaluate the effects of correctors in rescuing them; and 3) explore the effects of correctors on CFTR interactions with proteostasis components. RESULTS All four mutants exhibited lower protein expression than did wild type-CFTR, and they were degraded by proteasomes and aggresomes. At low temperature, only cells expressing the mutants L1077P and M1101K exhibited increased CFTR maturation. Co-administration of C4 and C18 showed the greatest effect, restoring functional expression and partial stability of CFTR bearing E92K, L1077P, or M1101K at the cell surface. However, this treatment was inefficient in rectifying the defect of CFTR bearing G85E. Correctors rescued CFTR mutants by reducing their interactions with proteostasis components associated with protein retention in the endoplasmic reticulum and ubiquitination. CONCLUSION Co-administration of C4 and C18 rescued CFTR transmembrane-domain mutants by remodeling the CFTR interactome.
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157
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Romani L, Oikonomou V, Moretti S, Iannitti RG, D'Adamo MC, Villella VR, Pariano M, Sforna L, Borghi M, Bellet MM, Fallarino F, Pallotta MT, Servillo G, Ferrari E, Puccetti P, Kroemer G, Pessia M, Maiuri L, Goldstein AL, Garaci E. Thymosin α1 represents a potential potent single-molecule-based therapy for cystic fibrosis. Nat Med 2017; 23:590-600. [PMID: 28394330 PMCID: PMC5420451 DOI: 10.1038/nm.4305] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 02/17/2017] [Indexed: 12/17/2022]
Abstract
Cystic fibrosis (CF) is caused by mutations in the gene encoding the cystic fibrosis transmembrane conductance regulator (CFTR) that compromise its chloride-channel activity. The most common mutation, p.Phe508del, results in the production of a misfolded CFTR protein, which has residual channel activity but is prematurely degraded. Because of the inherent complexity of the pathogenetic mechanisms involved in CF —which include impaired chloride permeability and persistent lung inflammation—a multidrug approach is required for efficacious CF therapy. To date, no individual, drug with pleiotropic beneficial effects for CF is available. Here we report on the ability of thymosin alpha 1 (Tα1)—a naturally occurring polypeptide with an excellent safety profile in the clinic when used as an adjuvant or an immunotherapeutic agent—to rectify the multiple tissue defects in CF mice as well as in cells from subjects with the p.Phe508del mutation. Tα1 displayed two combined properties that favorably opposed CF symptomatology; namely, it reduced inflammation and increased CFTR maturation, stability and activity. By virtue of this two-pronged action, Tα1 offers a strong potential to be an efficacious single molecule-based therapeutic agent in CF.
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Affiliation(s)
- Luigina Romani
- Department of Experimental Medicine, University of Perugia, Perugia, Italy
| | - Vasilis Oikonomou
- Department of Experimental Medicine, University of Perugia, Perugia, Italy
| | - Silvia Moretti
- Department of Experimental Medicine, University of Perugia, Perugia, Italy
| | - Rossana G Iannitti
- Department of Experimental Medicine, University of Perugia, Perugia, Italy
| | - Maria Cristina D'Adamo
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta
| | - Valeria R Villella
- European Institute for Research in Cystic Fibrosis, Division of Genetics and Cell Biology, San Raffaele Scientific Institute, Milan, Italy
| | - Marilena Pariano
- Department of Experimental Medicine, University of Perugia, Perugia, Italy
| | - Luigi Sforna
- Department of Experimental Medicine, University of Perugia, Perugia, Italy
| | - Monica Borghi
- Department of Experimental Medicine, University of Perugia, Perugia, Italy
| | - Marina M Bellet
- Department of Experimental Medicine, University of Perugia, Perugia, Italy
| | | | | | - Giuseppe Servillo
- Department of Experimental Medicine, University of Perugia, Perugia, Italy
| | - Eleonora Ferrari
- European Institute for Research in Cystic Fibrosis, Division of Genetics and Cell Biology, San Raffaele Scientific Institute, Milan, Italy
| | - Paolo Puccetti
- Department of Experimental Medicine, University of Perugia, Perugia, Italy
| | - Guido Kroemer
- Centre de Recherche des Cordeliers, INSERM U1138, Université Paris Descartes, Paris, France.,Metabolomics and Cell Biology Platforms, Institut Gustave Roussy, Villejuif, France.,Pôle de Biologie, Hôpital Européen Georges Pompidou, AP-HP, Paris, France.,Karolinska Institute, Department of Women's and Children's Health, Karolinska University Hospital, Stockholm, Sweden
| | - Mauro Pessia
- Department of Experimental Medicine, University of Perugia, Perugia, Italy.,Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta
| | - Luigi Maiuri
- European Institute for Research in Cystic Fibrosis, Division of Genetics and Cell Biology, San Raffaele Scientific Institute, Milan, Italy.,Department of Health Sciences, University of Piemonte Orientale, Novara, Italy
| | - Allan L Goldstein
- Department of Biochemistry and Molecular Medicine, George Washington University, School of Medicine and Health Sciences, Washington, DC, USA
| | - Enrico Garaci
- University San Raffaele and IRCCS San Raffaele, Rome, Italy
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158
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Langron E, Simone MI, Delalande CMS, Reymond JL, Selwood DL, Vergani P. Improved fluorescence assays to measure the defects associated with F508del-CFTR allow identification of new active compounds. Br J Pharmacol 2017; 174:525-539. [PMID: 28094839 DOI: 10.1111/bph.13715] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Revised: 01/06/2017] [Accepted: 01/10/2017] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND AND PURPOSE Cystic fibrosis (CF) is a debilitating disease caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, which codes for a Cl-/HCO3 - channel. F508del, the most common CF-associated mutation, causes both gating and biogenesis defects in the CFTR protein. This paper describes the optimization of two fluorescence assays, capable of measuring CFTR function and cellular localization, and their use in a pilot drug screen. EXPERIMENTAL APPROACH HEK293 cells expressing YFP-F508del-CFTR, in which halide sensitive YFP is tagged to the N-terminal of CFTR, were used to screen a small library of compounds based on the VX-770 scaffold. Cells expressing F508del-CFTR-pHTomato, in which a pH sensor is tagged to the fourth extracellular loop of CFTR, were used to measure CFTR plasma membrane exposure following chronic treatment with the novel potentiators. KEY RESULTS Active compounds with efficacy ~50% of VX-770, micromolar potency, and structurally distinct from VX-770 were identified in the screen. The F508del-CFTR-pHTomato assay suggests that the hit compound MS131A, unlike VX-770, does not decrease membrane exposure of F508del-CFTR. CONCLUSIONS AND IMPLICATIONS Most known potentiators have a negative influence on F508del-CFTR biogenesis/stability, which means membrane exposure needs to be monitored early during the development of drugs targeting CFTR. The combined use of the two fluorescence assays described here provides a useful tool for the identification of improved potentiators and correctors. The assays could also prove useful for basic scientific investigations on F508del-CFTR, and other CF-causing mutations.
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Affiliation(s)
- Emily Langron
- Research Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
| | - Michela I Simone
- Discipline of Chemistry, School of Environmental and Life Sciences, Priority Research Centre for Chemical Biology and Clinical Pharmacology, The University of Newcastle, Callaghan, NSW, Australia
| | | | - Jean-Louis Reymond
- Department of Chemistry and Biochemistry, University of Bern, Bern, Switzerland
| | - David L Selwood
- Wolfson Institute for Biomedical Research, University College London, London, UK
| | - Paola Vergani
- Research Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
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159
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Donaldson SH, Solomon GM, Zeitlin PL, Flume PA, Casey A, McCoy K, Zemanick ET, Mandagere A, Troha JM, Shoemaker SA, Chmiel JF, Taylor-Cousar JL. Pharmacokinetics and safety of cavosonstat (N91115) in healthy and cystic fibrosis adults homozygous for F508DEL-CFTR. J Cyst Fibros 2017; 16:371-379. [PMID: 28209466 DOI: 10.1016/j.jcf.2017.01.009] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 01/18/2017] [Accepted: 01/23/2017] [Indexed: 11/16/2022]
Abstract
BACKGROUND Cavosonstat (N91115), an orally bioavailable inhibitor of S-nitrosoglutathione reductase, promotes cystic fibrosis transmembrane conductance regulator (CFTR) maturation and plasma membrane stability, with a mechanism of action complementary to CFTR correctors and potentiators. METHODS A Phase I program evaluated pharmacokinetics, drug-drug interactions and safety of cavosonstat in healthy and cystic fibrosis (CF) subjects homozygous for F508del-CFTR. Exploratory outcomes included changes in sweat chloride in CF subjects. RESULTS Cavosonstat was rapidly absorbed and demonstrated linear and predictable pharmacokinetics. Exposure was unaffected by a high-fat meal or rifampin-mediated effects on drug metabolism and transport. Cavosonstat was well tolerated, with no dose-limiting toxicities or significant safety findings. At the highest dose, significant reductions from baseline in sweat chloride were observed (-4.1mmol/L; P=0.032) at day 28. CONCLUSIONS The favorable safety and clinical profile warrant further study of cavosonstat in CF. ClinicalTrials.gov Numbers: NCT02275936, NCT02013388, NCT02500667.
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Affiliation(s)
- Scott H Donaldson
- Cystic Fibrosis Research and Treatment Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
| | - George M Solomon
- Department of Medicine and the Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, AL, USA
| | - Pamela L Zeitlin
- Eudowood Division of Pediatric Respiratory Sciences, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Patrick A Flume
- Department of Medicine, Medical University of South Carolina, Charleston, SC, USA; Department of Pediatrics, Medical University of South Carolina, Charleston, SC, USA
| | - Alicia Casey
- Department of Medicine, Division of Respiratory Diseases, Boston Children's Hospital, Boston, MA, USA
| | - Karen McCoy
- Ohio State University, Nationwide Children's Hospital, Columbus, OH, USA
| | - Edith T Zemanick
- Department of Pediatrics, University of Colorado School of Medicine and Children's Hospital Colorado, Aurora, CO, USA
| | | | | | | | - James F Chmiel
- Department of Pediatrics, Case Western Reserve University School of Medicine and Rainbow Babies and Children's Hospital, Cleveland, OH, USA
| | - Jennifer L Taylor-Cousar
- Department of Internal Medicine, Pulmonary Division, National Jewish Health, University of Colorado Health Sciences Center, Denver, CO, USA; Department of Pediatrics, Pulmonary Division, National Jewish Health, University of Colorado Health Sciences Center, Denver, CO, USA
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160
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Piao H, Kim J, Noh SH, Kweon HS, Kim JY, Lee MG. Sec16A is critical for both conventional and unconventional secretion of CFTR. Sci Rep 2017; 7:39887. [PMID: 28067262 PMCID: PMC5220342 DOI: 10.1038/srep39887] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 11/29/2016] [Indexed: 12/16/2022] Open
Abstract
CFTR is a transmembrane protein that reaches the cell surface via the conventional Golgi mediated secretion pathway. Interestingly, ER-to-Golgi blockade or ER stress induces alternative GRASP-mediated, Golgi-bypassing unconventional trafficking of wild-type CFTR and the disease-causing ΔF508-CFTR, which has folding and trafficking defects. Here, we show that Sec16A, the key regulator of conventional ER-to-Golgi transport, plays a critical role in the ER exit of protein cargos during unconventional secretion. In an initial gene silencing screen, Sec16A knockdown abolished the unconventional secretion of wild-type and ΔF508-CFTR induced by ER-to-Golgi blockade, whereas the knockdown of other COPII-related components did not. Notably, during unconventional secretion, Sec16A was redistributed to cell periphery and associated with GRASP55 in mammalian cells. Molecular and morphological analyses revealed that IRE1α-mediated signaling is an upstream regulator of Sec16A during ER-to-Golgi blockade or ER stress associated unconventional secretion. These findings highlight a novel function of Sec16A as an essential mediator of ER stress-associated unconventional secretion.
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161
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Klimek C, Kathage B, Wördehoff J, Höhfeld J. BAG3-mediated proteostasis at a glance. J Cell Sci 2017; 130:2781-2788. [DOI: 10.1242/jcs.203679] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
ABSTRACT
Cellular and organismal survival depend on the ability to maintain the proteome, even under conditions that threaten protein integrity. BCL2-associated athanogene 3 (BAG3) is essential for protein homeostasis (proteostasis) in stressed cells. Owing to its multi-domain structure, it engages in diverse processes that are crucial for proteome maintenance. BAG3 promotes the activity of molecular chaperones, sequesters and concentrates misfolded proteins, initiates autophagic disposal, and balances transcription, translation and degradation. In this Cell Science at a Glance article and the accompanying poster, we discuss the functions of this multi-functional proteostasis tool with a focus on mechanical stress protection and describe the importance of BAG3 for human physiology and pathophysiology.
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Affiliation(s)
- Christina Klimek
- Institute for Cell Biology, University of Bonn, Ulrich-Haberland-Str. 61a, D-53121 Bonn, Germany
| | - Barbara Kathage
- Institute for Cell Biology, University of Bonn, Ulrich-Haberland-Str. 61a, D-53121 Bonn, Germany
| | - Judith Wördehoff
- Institute for Cell Biology, University of Bonn, Ulrich-Haberland-Str. 61a, D-53121 Bonn, Germany
| | - Jörg Höhfeld
- Institute for Cell Biology, University of Bonn, Ulrich-Haberland-Str. 61a, D-53121 Bonn, Germany
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162
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Chin S, Hung M, Bear CE. Current insights into the role of PKA phosphorylation in CFTR channel activity and the pharmacological rescue of cystic fibrosis disease-causing mutants. Cell Mol Life Sci 2017; 74:57-66. [PMID: 27722768 PMCID: PMC11107731 DOI: 10.1007/s00018-016-2388-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Accepted: 09/28/2016] [Indexed: 12/21/2022]
Abstract
Cystic fibrosis transmembrane conductance regulator (CFTR) channel gating is predominantly regulated by protein kinase A (PKA)-dependent phosphorylation. In addition to regulating CFTR channel activity, PKA phosphorylation is also involved in enhancing CFTR trafficking and mediating conformational changes at the interdomain interfaces of the protein. The major cystic fibrosis (CF)-causing mutation is the deletion of phenylalanine at position 508 (F508del); it causes many defects that affect CFTR trafficking, stability, and gating at the cell surface. Due to the multiple roles of PKA phosphorylation, there is growing interest in targeting PKA-dependent signaling for rescuing the trafficking and functional defects of F508del-CFTR. This review will discuss the effects of PKA phosphorylation on wild-type CFTR, the consequences of CF mutations on PKA phosphorylation, and the development of therapies that target PKA-mediated signaling.
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Affiliation(s)
- Stephanie Chin
- Programme of Molecular Structure and Function, Research Institute, Hospital for Sick Children, Toronto, Canada
- Department of Biochemistry, University of Toronto, Toronto, Canada
| | - Maurita Hung
- Programme of Molecular Structure and Function, Research Institute, Hospital for Sick Children, Toronto, Canada
| | - Christine E Bear
- Programme of Molecular Structure and Function, Research Institute, Hospital for Sick Children, Toronto, Canada.
- Department of Biochemistry, University of Toronto, Toronto, Canada.
- Department of Physiology, University of Toronto, Toronto, Canada.
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163
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Farinha CM, Canato S. From the endoplasmic reticulum to the plasma membrane: mechanisms of CFTR folding and trafficking. Cell Mol Life Sci 2017; 74:39-55. [PMID: 27699454 PMCID: PMC11107782 DOI: 10.1007/s00018-016-2387-7] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Accepted: 09/28/2016] [Indexed: 01/10/2023]
Abstract
CFTR biogenesis starts with its co-translational insertion into the membrane of endoplasmic reticulum and folding of the cytosolic domains, towards the acquisition of a fully folded compact native structure. Efficiency of this process is assessed by the ER quality control system that allows the exit of folded proteins but targets unfolded/misfolded CFTR to degradation. If allowed to leave the ER, CFTR is modified at the Golgi and reaches the post-Golgi compartments to be delivered to the plasma membrane where it functions as a cAMP- and phosphorylation-regulated chloride/bicarbonate channel. CFTR residence at the membrane is a balance of membrane delivery, endocytosis, and recycling. Several adaptors, motor, and scaffold proteins contribute to the regulation of CFTR stability and are involved in continuously assessing its structure through peripheral quality control systems. Regulation of CFTR biogenesis and traffic (and its dysregulation by mutations, such as the most common F508del) determine its overall activity and thus contribute to the fine modulation of chloride secretion and hydration of epithelial surfaces. This review covers old and recent knowledge on CFTR folding and trafficking from its synthesis to the regulation of its stability at the plasma membrane and highlights how several of these steps can be modulated to promote the rescue of mutant CFTR.
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Affiliation(s)
- Carlos M Farinha
- BioISI-Biosystems and Integrative Sciences Institute, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016, Lisbon, Portugal.
| | - Sara Canato
- BioISI-Biosystems and Integrative Sciences Institute, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016, Lisbon, Portugal
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164
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Adnan H, Zhang Z, Park HJ, Tailor C, Che C, Kamani M, Spitalny G, Binnington B, Lingwood C. Endoplasmic Reticulum-Targeted Subunit Toxins Provide a New Approach to Rescue Misfolded Mutant Proteins and Revert Cell Models of Genetic Diseases. PLoS One 2016; 11:e0166948. [PMID: 27935997 PMCID: PMC5147855 DOI: 10.1371/journal.pone.0166948] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2016] [Accepted: 11/06/2016] [Indexed: 01/08/2023] Open
Abstract
Many germ line diseases stem from a relatively minor disturbance in mutant protein endoplasmic reticulum (ER) 3D assembly. Chaperones are recruited which, on failure to correct folding, sort the mutant for retrotranslocation and cytosolic proteasomal degradation (ER-associated degradation-ERAD), to initiate/exacerbate deficiency-disease symptoms. Several bacterial (and plant) subunit toxins, retrograde transport to the ER after initial cell surface receptor binding/internalization. The A subunit has evolved to mimic a misfolded protein and hijack the ERAD membrane translocon (dislocon), to effect cytosolic access and cytopathology. We show such toxins compete for ERAD to rescue endogenous misfolded proteins. Cholera toxin or verotoxin (Shiga toxin) containing genetically inactivated (± an N-terminal polyleucine tail) A subunit can, within 2–4 hrs, temporarily increase F508delCFTR protein, the major cystic fibrosis (CF) mutant (5-10x), F508delCFTR Golgi maturation (<10x), cell surface expression (20x) and chloride transport (2x) in F508del CFTR transfected cells and patient-derived F508delCFTR bronchiolar epithelia, without apparent cytopathology. These toxoids also increase glucocerobrosidase (GCC) in N370SGCC Gaucher Disease fibroblasts (3x), another ERAD–exacerbated misfiling disease. We identify a new, potentially benign approach to the treatment of certain genetic protein misfolding diseases.
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Affiliation(s)
- Humaira Adnan
- Division of Molecular Structure and Function, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Zhenbo Zhang
- Division of Molecular Structure and Function, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Hyun-Joo Park
- Division of Molecular Structure and Function, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Chetankumar Tailor
- Division of Cell Biology, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Clare Che
- Division of Molecular Structure and Function, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Mustafa Kamani
- Division of Molecular Structure and Function, The Hospital for Sick Children, Toronto, Ontario, Canada
| | | | - Beth Binnington
- Division of Molecular Structure and Function, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Clifford Lingwood
- Division of Molecular Structure and Function, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Biochemistry, University of Toronto, Ontario, Canada
- Department of Laboratory Medicine & Pathobiology, University of Toronto, Ontario, Canada
- * E-mail:
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165
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Veit G, Avramescu RG, Chiang AN, Houck SA, Cai Z, Peters KW, Hong JS, Pollard HB, Guggino WB, Balch WE, Skach WR, Cutting GR, Frizzell RA, Sheppard DN, Cyr DM, Sorscher EJ, Brodsky JL, Lukacs GL. From CFTR biology toward combinatorial pharmacotherapy: expanded classification of cystic fibrosis mutations. Mol Biol Cell 2016; 27:424-33. [PMID: 26823392 PMCID: PMC4751594 DOI: 10.1091/mbc.e14-04-0935] [Citation(s) in RCA: 386] [Impact Index Per Article: 48.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
More than 2000 mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) have been described that confer a range of molecular cell biological and functional phenotypes. Most of these mutations lead to compromised anion conductance at the apical plasma membrane of secretory epithelia and cause cystic fibrosis (CF) with variable disease severity. Based on the molecular phenotypic complexity of CFTR mutants and their susceptibility to pharmacotherapy, it has been recognized that mutations may impose combinatorial defects in CFTR channel biology. This notion led to the conclusion that the combination of pharmacotherapies addressing single defects (e.g., transcription, translation, folding, and/or gating) may show improved clinical benefit over available low-efficacy monotherapies. Indeed, recent phase 3 clinical trials combining ivacaftor (a gating potentiator) and lumacaftor (a folding corrector) have proven efficacious in CF patients harboring the most common mutation (deletion of residue F508, ΔF508, or Phe508del). This drug combination was recently approved by the U.S. Food and Drug Administration for patients homozygous for ΔF508. Emerging studies of the structural, cell biological, and functional defects caused by rare mutations provide a new framework that reveals a mixture of deficiencies in different CFTR alleles. Establishment of a set of combinatorial categories of the previously defined basic defects in CF alleles will aid the design of even more efficacious therapeutic interventions for CF patients.
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Affiliation(s)
- Gudio Veit
- Department of Physiology, McGill University, Montréal, QC H3G 1Y6, Canada
| | - Radu G Avramescu
- Department of Physiology, McGill University, Montréal, QC H3G 1Y6, Canada
| | - Annette N Chiang
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260
| | - Scott A Houck
- Marsico Lung Institute, School of Medicine, University of North Carolina, Chapel Hill, NC 27514
| | - Zhiwei Cai
- School of Physiology & Pharmacology, University of Bristol, Bristol BS8 1TD, United Kingdom
| | - Kathryn W Peters
- Department of Cell Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15261
| | - Jeong S Hong
- Department of Cellular, Developmental, and Integrative Biology, University of Alabama, Birmingham, AL 35294
| | - Harvey B Pollard
- Department of Anatomy, Physiology and Genetics and Center for Medical Proteomics, Uniformed Services University of the Health Sciences, Bethesda, MD 20814
| | - William B Guggino
- Department of Physiology, Johns Hopkins University, Baltimore, MD 21205
| | - William E Balch
- Department of Chemical Physiology, Skaggs Institute of Chemical Physiology, Scripps Research Institute, La Jolla, CA 92037
| | - William R Skach
- Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, OR 97239
| | - Garry R Cutting
- McKusick-Nathans Institute of Genetic Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD 21205
| | - Raymond A Frizzell
- Department of Cell Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15261
| | - David N Sheppard
- School of Physiology & Pharmacology, University of Bristol, Bristol BS8 1TD, United Kingdom
| | - Douglas M Cyr
- Marsico Lung Institute, School of Medicine, University of North Carolina, Chapel Hill, NC 27514
| | - Eric J Sorscher
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30322
| | - Jeffrey L Brodsky
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260
| | - Gergely L Lukacs
- Department of Physiology, McGill University, Montréal, QC H3G 1Y6, Canada Department of Biochemistry, McGill University, Montréal, QC H3G 1Y6, Canada GRASP, McGill University, Montréal, QC H3G 1Y6, Canada
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166
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Ramachandran S, Osterhaus SR, Parekh KR, Jacobi AM, Behlke MA, McCray PB. SYVN1, NEDD8, and FBXO2 Proteins Regulate ΔF508 Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) Ubiquitin-mediated Proteasomal Degradation. J Biol Chem 2016; 291:25489-25504. [PMID: 27756846 DOI: 10.1074/jbc.m116.754283] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Revised: 10/07/2016] [Indexed: 11/06/2022] Open
Abstract
We previously reported that delivery of a microRNA-138 mimic or siRNA against SIN3A to cultured cystic fibrosis (ΔF508/ΔF508) airway epithelia partially restored ΔF508-cystic fibrosis transmembrane conductance regulator (CFTR)-mediated cAMP-stimulated Cl- conductance. We hypothesized that dissecting this microRNA-138/SIN3A-regulated gene network would identify individual proteins contributing to the rescue of ΔF508-CFTR function. Among the genes in the network, we rigorously validated candidates using functional CFTR maturation and electrolyte transport assays in polarized airway epithelia. We found that depletion of the ubiquitin ligase SYVN1, the ubiquitin/proteasome system regulator NEDD8, or the F-box protein FBXO2 partially restored ΔF508-CFTR-mediated Cl- transport in primary cultures of human cystic fibrosis airway epithelia. Moreover, knockdown of SYVN1, NEDD8, or FBXO2 in combination with corrector compound 18 further potentiated rescue of ΔF508-CFTR-mediated Cl- conductance. This study provides new knowledge of the CFTR biosynthetic pathway. It suggests that SYVN1 and FBXO2 represent two distinct multiprotein complexes that may degrade ΔF508-CFTR in airway epithelia and identifies a new role for NEDD8 in regulating ΔF508-CFTR ubiquitination.
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Affiliation(s)
- Shyam Ramachandran
- From the Department of Pediatrics, Pappajohn Biomedical Institute, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242 and
| | - Samantha R Osterhaus
- From the Department of Pediatrics, Pappajohn Biomedical Institute, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242 and
| | - Kalpaj R Parekh
- From the Department of Pediatrics, Pappajohn Biomedical Institute, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242 and
| | | | | | - Paul B McCray
- From the Department of Pediatrics, Pappajohn Biomedical Institute, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242 and
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167
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Wanitchakool P, Ousingsawat J, Sirianant L, MacAulay N, Schreiber R, Kunzelmann K. Cl - channels in apoptosis. EUROPEAN BIOPHYSICS JOURNAL : EBJ 2016; 45:599-610. [PMID: 27270446 DOI: 10.1007/s00249-016-1140-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 05/06/2016] [Accepted: 05/14/2016] [Indexed: 12/28/2022]
Abstract
A remarkable feature of apoptosis is the initial massive cell shrinkage, which requires opening of ion channels to allow release of K+, Cl-, and organic osmolytes to drive osmotic water movement and cell shrinkage. This article focuses on the role of the Cl- channels LRRC8, TMEM16/anoctamin, and cystic fibrosis transmembrane conductance regulator (CFTR) in cellular apoptosis. LRRC8A-E has been identified as a volume-regulated anion channel expressed in many cell types. It was shown to be required for regulatory and apoptotic volume decrease (RVD, AVD) in cultured cell lines. Its presence also determines sensitivity towards cytostatic drugs such as cisplatin. Recent data point to a molecular and functional relationship of LRRC8A and anoctamins (ANOs). ANO6, 9, and 10 (TMEM16F, J, and K) augment apoptotic Cl- currents and AVD, but it remains unclear whether these anoctamins operate as Cl- channels or as regulators of other apoptotic Cl- channels, such as LRRC8. CFTR has been known for its proapoptotic effects for some time, and this effect may be based on glutathione release from the cell and increase in cytosolic reactive oxygen species (ROS). Although we find that CFTR is activated by cell swelling, it is possible that CFTR serves RVD/AVD through accumulation of ROS and activation of independent membrane channels such as ANO6. Thus activation of ANO6 will support cell shrinkage and induce additional apoptotic events, such as membrane phospholipid scrambling.
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Affiliation(s)
- Podchanart Wanitchakool
- Institut für Physiologie, Universität Regensburg, Universitätsstraße 31, 93053, Regensburg, Germany
| | - Jiraporn Ousingsawat
- Institut für Physiologie, Universität Regensburg, Universitätsstraße 31, 93053, Regensburg, Germany
| | - Lalida Sirianant
- Institut für Physiologie, Universität Regensburg, Universitätsstraße 31, 93053, Regensburg, Germany
| | - Nanna MacAulay
- Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Rainer Schreiber
- Institut für Physiologie, Universität Regensburg, Universitätsstraße 31, 93053, Regensburg, Germany
| | - Karl Kunzelmann
- Institut für Physiologie, Universität Regensburg, Universitätsstraße 31, 93053, Regensburg, Germany.
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168
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Sabusap CM, Wang W, McNicholas CM, Chung WJ, Fu L, Wen H, Mazur M, Kirk KL, Collawn JF, Hong JS, Sorscher EJ. Analysis of cystic fibrosis-associated P67L CFTR illustrates barriers to personalized therapeutics for orphan diseases. JCI Insight 2016; 1. [PMID: 27660821 DOI: 10.1172/jci.insight.86581] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Emerging knowledge indicates the difficulty in categorizing unusual cystic fibrosis (CF) mutations, with regard to both pathogenic mechanism and theratype. As case in point, we present data concerning P67L mutation of the cystic fibrosis transmembrane conductance regulator (CFTR), a defect carried by a small number of individuals with CF and sometimes attributed to a channel conductance abnormality. Findings from our laboratory and others establish that P67L causes protein misfolding, disrupts maturation, confers gating defects, is thermally stable, and exhibits near normal conductance. These results provide one framework by which rare CF alleles such as P67L can be more comprehensively profiled vis-à-vis molecular pathogenesis. We also demonstrate that emerging CF treatments - ivacaftor and lumacaftor - can mediate pronounced pharmacologic activation of P67L CFTR. Infrequent CF alleles are often improperly characterized, in part, due to the small numbers of patients involved. Moreover, access to new personalized treatments among patients with ultra-orphan genotypes has been limited by difficulty arranging phase III clinical trials, and off-label prescribing has been impaired by high drug cost and difficulty arranging third party reimbursement. Rare CFTR mutations such as P67L are emblematic of the challenges to "precision" medicine, including use of the best available mechanistic knowledge to treat patients with unusual forms of disease.
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Affiliation(s)
- Carleen M Sabusap
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama, Birmingham, Alabama, USA
| | - Wei Wang
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama, Birmingham, Alabama, USA
| | - Carmel M McNicholas
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama, Birmingham, Alabama, USA
| | - W Joon Chung
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama, Birmingham, Alabama, USA
| | - Lianwu Fu
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama, Birmingham, Alabama, USA
| | - Hui Wen
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama, Birmingham, Alabama, USA
| | - Marina Mazur
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama, Birmingham, Alabama, USA
| | - Kevin L Kirk
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama, Birmingham, Alabama, USA
| | - James F Collawn
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama, Birmingham, Alabama, USA
| | - Jeong S Hong
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama, Birmingham, Alabama, USA
| | - Eric J Sorscher
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama, Birmingham, Alabama, USA.; Emory University, Atlanta, Georgia, USA
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169
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Esmail S, Yao Y, Kartner N, Li J, Reithmeier RAF, Manolson MF. N-Linked Glycosylation Is Required for Vacuolar H+-ATPase (V-ATPase)a4Subunit Stability, Assembly, and Cell Surface Expression. J Cell Biochem 2016; 117:2757-2768. [DOI: 10.1002/jcb.25574] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Accepted: 04/21/2016] [Indexed: 12/11/2022]
Affiliation(s)
- Sally Esmail
- Faculty of Dentistry, Dental Research Institute; University of Toronto; Toronto Ontario Canada M5G 1G6
| | - Yeqi Yao
- Faculty of Dentistry, Dental Research Institute; University of Toronto; Toronto Ontario Canada M5G 1G6
| | - Norbert Kartner
- Faculty of Dentistry, Dental Research Institute; University of Toronto; Toronto Ontario Canada M5G 1G6
| | - Jing Li
- Department of Biochemistry; University of Toronto; Toronto Ontario Canada M5S 1A8
| | | | - Morris F. Manolson
- Faculty of Dentistry, Dental Research Institute; University of Toronto; Toronto Ontario Canada M5G 1G6
- Department of Biochemistry; University of Toronto; Toronto Ontario Canada M5S 1A8
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170
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Lopes-Pacheco M. CFTR Modulators: Shedding Light on Precision Medicine for Cystic Fibrosis. Front Pharmacol 2016; 7:275. [PMID: 27656143 PMCID: PMC5011145 DOI: 10.3389/fphar.2016.00275] [Citation(s) in RCA: 95] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Accepted: 08/11/2016] [Indexed: 12/15/2022] Open
Abstract
Cystic fibrosis (CF) is the most common life-threatening monogenic disease afflicting Caucasian people. It affects the respiratory, gastrointestinal, glandular and reproductive systems. The major cause of morbidity and mortality in CF is the respiratory disorder caused by a vicious cycle of obstruction of the airways, inflammation and infection that leads to epithelial damage, tissue remodeling and end-stage lung disease. Over the past decades, life expectancy of CF patients has increased due to early diagnosis and improved treatments; however, these patients still present limited quality of life. Many attempts have been made to rescue CF transmembrane conductance regulator (CFTR) expression, function and stability, thereby overcoming the molecular basis of CF. Gene and protein variances caused by CFTR mutants lead to different CF phenotypes, which then require different treatments to quell the patients' debilitating symptoms. In order to seek better approaches to treat CF patients and maximize therapeutic effects, CFTR mutants have been stratified into six groups (although several of these mutations present pleiotropic defects). The research with CFTR modulators (read-through agents, correctors, potentiators, stabilizers and amplifiers) has achieved remarkable progress, and these drugs are translating into pharmaceuticals and personalized treatments for CF patients. This review summarizes the main molecular and clinical features of CF, emphasizes the latest clinical trials using CFTR modulators, sheds light on the molecular mechanisms underlying these new and emerging treatments, and discusses the major breakthroughs and challenges to treating all CF patients.
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Affiliation(s)
- Miquéias Lopes-Pacheco
- Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro Rio de Janeiro, Brazil
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171
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Ilie A, Gao AYL, Reid J, Boucher A, McEwan C, Barrière H, Lukacs GL, McKinney RA, Orlowski J. A Christianson syndrome-linked deletion mutation (∆(287)ES(288)) in SLC9A6 disrupts recycling endosomal function and elicits neurodegeneration and cell death. Mol Neurodegener 2016; 11:63. [PMID: 27590723 PMCID: PMC5010692 DOI: 10.1186/s13024-016-0129-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 08/27/2016] [Indexed: 01/19/2023] Open
Abstract
Background Christianson Syndrome, a recently identified X-linked neurodevelopmental disorder, is caused by mutations in the human gene SLC9A6 encoding the recycling endosomal alkali cation/proton exchanger NHE6. The patients have pronounced limitations in cognitive ability, motor skills and adaptive behaviour. However, the mechanistic basis for this disorder is poorly understood as few of the more than 20 mutations identified thus far have been studied in detail. Methods Here, we examined the molecular and cellular consequences of a 6 base-pair deletion of amino acids Glu287 and Ser288 (∆ES) in the predicted seventh transmembrane helix of human NHE6 expressed in established cell lines (CHO/AP-1, HeLa and neuroblastoma SH-SY5Y) and primary cultures of mouse hippocampal neurons by measuring levels of protein expression, stability, membrane trafficking, endosomal function and cell viability. Results In the cell lines, immunoblot analyses showed that the nascent mutant protein was properly synthesized and assembled as a homodimer, but its oligosaccharide maturation and half-life were markedly reduced compared to wild-type (WT) and correlated with enhanced ubiquitination leading to both proteasomal and lysosomal degradation. Despite this instability, a measurable fraction of the transporter was correctly sorted to the plasma membrane. However, the rates of clathrin-mediated endocytosis of the ∆ES mutant as well as uptake of companion vesicular cargo, such as the ligand-bound transferrin receptor, were significantly reduced and correlated with excessive endosomal acidification. Notably, ectopic expression of ∆ES but not WT induced apoptosis when examined in AP-1 cells. Similarly, in transfected primary cultures of mouse hippocampal neurons, membrane trafficking of the ∆ES mutant was impaired and elicited marked reductions in total dendritic length, area and arborization, and triggered apoptotic cell death. Conclusions These results suggest that loss-of-function mutations in NHE6 disrupt recycling endosomal function and trafficking of cargo which ultimately leads to neuronal degeneration and cell death in Christianson Syndrome. Electronic supplementary material The online version of this article (doi:10.1186/s13024-016-0129-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Alina Ilie
- Department of Physiology, McGill University, Bellini Life Sciences Bldg., Rm, 166, 3649 Promenade Sir-William-Osler, Montreal, QC, H3G 0B1, Canada
| | - Andy Y L Gao
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Canada
| | - Jonathan Reid
- Department of Physiology, McGill University, Bellini Life Sciences Bldg., Rm, 166, 3649 Promenade Sir-William-Osler, Montreal, QC, H3G 0B1, Canada
| | - Annie Boucher
- Department of Physiology, McGill University, Bellini Life Sciences Bldg., Rm, 166, 3649 Promenade Sir-William-Osler, Montreal, QC, H3G 0B1, Canada
| | - Cassandra McEwan
- Department of Physiology, McGill University, Bellini Life Sciences Bldg., Rm, 166, 3649 Promenade Sir-William-Osler, Montreal, QC, H3G 0B1, Canada
| | - Hervé Barrière
- Department of Physiology, McGill University, Bellini Life Sciences Bldg., Rm, 166, 3649 Promenade Sir-William-Osler, Montreal, QC, H3G 0B1, Canada
| | - Gergely L Lukacs
- Department of Physiology, McGill University, Bellini Life Sciences Bldg., Rm, 166, 3649 Promenade Sir-William-Osler, Montreal, QC, H3G 0B1, Canada
| | - R Anne McKinney
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Canada
| | - John Orlowski
- Department of Physiology, McGill University, Bellini Life Sciences Bldg., Rm, 166, 3649 Promenade Sir-William-Osler, Montreal, QC, H3G 0B1, Canada.
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172
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Huguet F, Calvez ML, Benz N, Le Hir S, Mignen O, Buscaglia P, Horgen FD, Férec C, Kerbiriou M, Trouvé P. Function and regulation of TRPM7, as well as intracellular magnesium content, are altered in cells expressing ΔF508-CFTR and G551D-CFTR. Cell Mol Life Sci 2016; 73:3351-73. [PMID: 26874684 PMCID: PMC11108291 DOI: 10.1007/s00018-016-2149-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Revised: 01/14/2016] [Accepted: 01/25/2016] [Indexed: 02/03/2023]
Abstract
Cystic fibrosis (CF), one of the most common fatal hereditary disorders, is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. The CFTR gene product is a multidomain adenosine triphosphate-binding cassette (ABC) protein that functions as a chloride (Cl(-)) channel that is regulated by intracellular magnesium [Mg(2+)]i. The most common mutations in CFTR are a deletion of a phenylalanine residue at position 508 (ΔF508-CFTR, 70-80 % of CF phenotypes) and a Gly551Asp substitution (G551D-CFTR, 4-5 % of alleles), which lead to decreased or almost abolished Cl(-) channel function, respectively. Magnesium ions have to be finely regulated within cells for optimal expression and function of CFTR. Therefore, the melastatin-like transient receptor potential cation channel, subfamily M, member 7 (TRPM7), which is responsible for Mg(2+) entry, was studies and [Mg(2+)]i measured in cells stably expressing wildtype CFTR, and two mutant proteins (ΔF508-CFTR and G551D-CFTR). This study shows for the first time that [Mg(2+)]i is decreased in cells expressing ΔF508-CFTR and G551D-CFTR mutated proteins. It was also observed that the expression of the TRPM7 protein is increased; however, membrane localization was altered for both ΔF508del-CFTR and G551D-CFTR. Furthermore, both the function and regulation of the TRPM7 channel regarding Mg(2+) is decreased in the cells expressing the mutated CFTR. Ca(2+) influx via TRPM7 were also modified in cells expressing a mutated CFTR. Therefore, there appears to be a direct involvement of TRPM7 in CF physiopathology. Finally, we propose that the TRPM7 activator Naltriben is a new potentiator for G551D-CFTR as the function of this mutant increases upon activation of TRPM7 by Naltriben.
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Affiliation(s)
- F Huguet
- Inserm, UMR1078, 46, rue Félix le Dantec, CS 51819, 29218, Brest Cedex 2, France
- Faculté de Médecine et des sciences de la santé, Université de Bretagne Occidentale, Brest, 29200, France
| | - M L Calvez
- Inserm, UMR1078, 46, rue Félix le Dantec, CS 51819, 29218, Brest Cedex 2, France
- Faculté de Médecine et des sciences de la santé, Université de Bretagne Occidentale, Brest, 29200, France
- Association G. Saleun, Brest, 29218, France
| | - N Benz
- Inserm, UMR1078, 46, rue Félix le Dantec, CS 51819, 29218, Brest Cedex 2, France
- Association G. Saleun, Brest, 29218, France
| | - S Le Hir
- Inserm, UMR1078, 46, rue Félix le Dantec, CS 51819, 29218, Brest Cedex 2, France
- Laboratoire de Génétique Moléculaire, Hôpital Morvan, C.H.U. Brest, Brest, 29200, France
| | - O Mignen
- Inserm, UMR1078, 46, rue Félix le Dantec, CS 51819, 29218, Brest Cedex 2, France
- Faculté de Médecine et des sciences de la santé, Université de Bretagne Occidentale, Brest, 29200, France
| | - P Buscaglia
- Inserm, UMR1078, 46, rue Félix le Dantec, CS 51819, 29218, Brest Cedex 2, France
- Faculté de Médecine et des sciences de la santé, Université de Bretagne Occidentale, Brest, 29200, France
| | - F D Horgen
- Laboratory of Marine Biological Chemistry, Department of Natural Sciences, Hawaii Pacific University, Kaneohe, HI, 96744, USA
| | - C Férec
- Inserm, UMR1078, 46, rue Félix le Dantec, CS 51819, 29218, Brest Cedex 2, France.
- Faculté de Médecine et des sciences de la santé, Université de Bretagne Occidentale, Brest, 29200, France.
- Laboratoire de Génétique Moléculaire, Hôpital Morvan, C.H.U. Brest, Brest, 29200, France.
- Etablissement Français du Sang - Bretagne, Brest, 29200, France.
| | - M Kerbiriou
- Inserm, UMR1078, 46, rue Félix le Dantec, CS 51819, 29218, Brest Cedex 2, France
- Faculté de Médecine et des sciences de la santé, Université de Bretagne Occidentale, Brest, 29200, France
| | - P Trouvé
- Inserm, UMR1078, 46, rue Félix le Dantec, CS 51819, 29218, Brest Cedex 2, France.
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Peng YJ, Huang JJ, Wu HH, Hsieh HY, Wu CY, Chen SC, Chen TY, Tang CY. Regulation of CLC-1 chloride channel biosynthesis by FKBP8 and Hsp90β. Sci Rep 2016; 6:32444. [PMID: 27580824 PMCID: PMC5007535 DOI: 10.1038/srep32444] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 08/10/2016] [Indexed: 01/23/2023] Open
Abstract
Mutations in human CLC-1 chloride channel are associated with the skeletal muscle disorder myotonia congenita. The disease-causing mutant A531V manifests enhanced proteasomal degradation of CLC-1. We recently found that CLC-1 degradation is mediated by cullin 4 ubiquitin ligase complex. It is currently unclear how quality control and protein degradation systems coordinate with each other to process the biosynthesis of CLC-1. Herein we aim to ascertain the molecular nature of the protein quality control system for CLC-1. We identified three CLC-1-interacting proteins that are well-known heat shock protein 90 (Hsp90)-associated co-chaperones: FK506-binding protein 8 (FKBP8), activator of Hsp90 ATPase homolog 1 (Aha1), and Hsp70/Hsp90 organizing protein (HOP). These co-chaperones promote both the protein level and the functional expression of CLC-1 wild-type and A531V mutant. CLC-1 biosynthesis is also facilitated by the molecular chaperones Hsc70 and Hsp90β. The protein stability of CLC-1 is notably increased by FKBP8 and the Hsp90β inhibitor 17-allylamino-17-demethoxygeldanamycin (17-AAG) that substantially suppresses cullin 4 expression. We further confirmed that cullin 4 may interact with Hsp90β and FKBP8. Our data are consistent with the idea that FKBP8 and Hsp90β play an essential role in the late phase of CLC-1 quality control by dynamically coordinating protein folding and degradation.
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Affiliation(s)
- Yi-Jheng Peng
- Department of Physiology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Jing-Jia Huang
- Department of Physiology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Hao-Han Wu
- Department of Physiology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Hsin-Ying Hsieh
- Department of Physiology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Chia-Ying Wu
- Department of Physiology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Shu-Ching Chen
- Department of Medical Research, National Taiwan University Hospital, Taipei, Taiwan
| | - Tsung-Yu Chen
- Neuroscience Center, University of California, Davis, USA
| | - Chih-Yung Tang
- Department of Physiology, College of Medicine, National Taiwan University, Taipei, Taiwan.,Graduate Institute of Brain and Mind Sciences, College of Medicine, National Taiwan University, Taipei, Taiwan
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174
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Staudt C, Gilis F, Boonen M, Jadot M. Molecular determinants that mediate the sorting of human ATG9A from the endoplasmic reticulum. BIOCHIMICA ET BIOPHYSICA ACTA 2016; 1863:2299-310. [PMID: 27316455 DOI: 10.1016/j.bbamcr.2016.06.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Revised: 06/07/2016] [Accepted: 06/14/2016] [Indexed: 11/15/2022]
Abstract
ATG9A is a multispanning membrane protein required for autophagosome formation. Under basal conditions, neosynthesized ATG9A proteins travel to the Golgi apparatus and cycle between the trans-Golgi network and endosomes. In the present work, we searched for molecular determinants involved in the subcellular trafficking of human ATG9A in HeLa cells using sequential deletions and point mutations. Deletion of amino acids L(340) to L(354) resulted in the retention of ATG9A in the endoplasmic reticulum. In addition, we found that substitution of the L(711)YM(713) sequence (located in the C-terminal region of ATG9A) by alanine residues severely impaired its transport through the Golgi apparatus. This defect could be corrected by oligomerization of the mutant protein with co-transfected wild-type ATG9A, suggesting that ATG9A oligomerization may help its sorting through biosynthetic compartments. Lastly, the study of the consequences of the LYM/AAA mutation on the intracellular trafficking of ATG9A highlighted that some newly synthesized ATG9A can bypass the Golgi apparatus to reach the plasma membrane. Taken together, these findings provide new insights into the intracellular pathways followed by ATG9A to reach different subcellular compartments, and into the intramolecular determinants that drive the sorting of this protein.
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Affiliation(s)
- Catherine Staudt
- URPhyM-Laboratoire de Chimie Physiologique, Université de Namur, Belgium
| | - Florentine Gilis
- URPhyM-Laboratoire de Chimie Physiologique, Université de Namur, Belgium
| | - Marielle Boonen
- URPhyM-Laboratoire de Chimie Physiologique, Université de Namur, Belgium
| | - Michel Jadot
- URPhyM-Laboratoire de Chimie Physiologique, Université de Namur, Belgium.
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175
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McClure ML, Barnes S, Brodsky JL, Sorscher EJ. Trafficking and function of the cystic fibrosis transmembrane conductance regulator: a complex network of posttranslational modifications. Am J Physiol Lung Cell Mol Physiol 2016; 311:L719-L733. [PMID: 27474090 DOI: 10.1152/ajplung.00431.2015] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 07/26/2016] [Indexed: 12/19/2022] Open
Abstract
Posttranslational modifications add diversity to protein function. Throughout its life cycle, the cystic fibrosis transmembrane conductance regulator (CFTR) undergoes numerous covalent posttranslational modifications (PTMs), including glycosylation, ubiquitination, sumoylation, phosphorylation, and palmitoylation. These modifications regulate key steps during protein biogenesis, such as protein folding, trafficking, stability, function, and association with protein partners and therefore may serve as targets for therapeutic manipulation. More generally, an improved understanding of molecular mechanisms that underlie CFTR PTMs may suggest novel treatment strategies for CF and perhaps other protein conformational diseases. This review provides a comprehensive summary of co- and posttranslational CFTR modifications and their significance with regard to protein biogenesis.
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Affiliation(s)
- Michelle L McClure
- Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, Alabama
| | - Stephen Barnes
- Department of Pharmacology and Toxicology, University of Alabama at Birmingham, Birmingham, Alabama
| | - Jeffrey L Brodsky
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania; and
| | - Eric J Sorscher
- Department of Pediatrics, Emory University, Atlanta, Georgia
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176
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Kim WK, Yun S, Park CK, Bauer S, Kim J, Lee MG, Kim H. Sustained Mutant KIT Activation in the Golgi Complex Is Mediated by PKC-θ in Gastrointestinal Stromal Tumors. Clin Cancer Res 2016; 23:845-856. [PMID: 27440273 DOI: 10.1158/1078-0432.ccr-16-0521] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Revised: 06/18/2016] [Accepted: 07/11/2016] [Indexed: 11/16/2022]
Abstract
PURPOSE Tumorigenesis of gastrointestinal stromal tumors (GIST) is driven by gain-of-function mutations in the KIT gene, which result in overexpression of activated mutant KIT proteins (MT-KIT). However, the mechanism of MT-KIT overexpression is poorly understood. EXPERIMENTAL DESIGN By protein expression analysis and immunofluorescent microscopic analysis, we determine the stability and localization of MT-KIT in four GIST cell lines with different mutations and HeLa cells transfected with mutant KIT model vectors. We also used 154 human GIST tissues to analyze the relationship between the expression of PKC-θ and MT-KITs, and correlations between PKC-θ overexpression and clinicopathological parameters. RESULTS We report that four different MT-KIT proteins are intrinsically less stable than wild-type KIT due to proteasome-mediated degradation and abnormally localized to the endoplasmic reticulum (ER) or the Golgi complex. By screening a MT-KIT-stabilizing factor, we find that PKC-θ is strongly and exclusively expressed in GISTs and interacts with intracellular MT-KIT to promote its stabilization by increased retention in the Golgi complex. In addition, Western blotting analysis using 50 GIST samples shows strong correlation between PKC-θ and MT-KIT expression (correlation coefficient = 0.682, P < 0.000001). Immunohistochemical analysis using 154 GISTs further demonstrates that PKC-θ overexpression significantly correlates with several clinicopathological parameters such as high tumor grade, frequent recurrence/metastasis, and poor patient survival. CONCLUSIONS Our findings suggest that sustained MT-KIT overexpression through PKC-θ-mediated stabilization in the Golgi contributes to GIST progression and provides a rationale for anti-PKC-θ therapy in GISTs. Clin Cancer Res; 23(3); 845-56. ©2016 AACR.
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Affiliation(s)
- Won Kyu Kim
- Department of Pathology and Brain Korea 21 PLUS Projects for Medical Science, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - SeongJu Yun
- Department of Pathology and Brain Korea 21 PLUS Projects for Medical Science, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Cheol Keun Park
- Department of Pathology and Brain Korea 21 PLUS Projects for Medical Science, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Sebastian Bauer
- Sarcoma Center, West German Cancer Center, University Hospital Essen, University Duisburg-Essen, Essen, Germany and German Cancer Consortium (DKTK), Heidelberg, Germany
| | - Jiyoon Kim
- Department of Pharmacology, Pharmacogenomic Research Center for Membrane Transporters, Brain Korea 21 PLUS Project for Medical Sciences, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Min Goo Lee
- Department of Pharmacology, Pharmacogenomic Research Center for Membrane Transporters, Brain Korea 21 PLUS Project for Medical Sciences, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Hoguen Kim
- Department of Pathology and Brain Korea 21 PLUS Projects for Medical Science, Yonsei University College of Medicine, Seoul, Republic of Korea.
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177
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Avci D, Lemberg MK. Clipping or Extracting: Two Ways to Membrane Protein Degradation. Trends Cell Biol 2016; 25:611-622. [PMID: 26410407 DOI: 10.1016/j.tcb.2015.07.003] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Revised: 06/18/2015] [Accepted: 07/17/2015] [Indexed: 12/20/2022]
Abstract
Protein degradation is a fundamentally important process that allows cells to recognize and remove damaged protein species and to regulate protein abundance according to functional need. A fundamental challenge is to understand how membrane proteins are recognized and removed from cellular organelles. While most of our understanding of this mechanism comes from studies on p97/Cdc48-mediated protein dislocation along the endoplasmic reticulum (ER)-associated degradation (ERAD) pathway, recent studies have revealed intramembrane proteolysis to be an additional mechanism that can extract transmembrane segments. Here, we review these two principles in membrane protein degradation and discuss how intramembrane proteolysis, which introduces an irreversible step in protein dislocation, is used to drive regulated protein turnover.
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Affiliation(s)
- Dönem Avci
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), DKFZ-ZMBH Allianz, Im Neuenheimer Feld 282, 69120 Heidelberg, Germany
| | - Marius K Lemberg
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), DKFZ-ZMBH Allianz, Im Neuenheimer Feld 282, 69120 Heidelberg, Germany.
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178
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Arora K, Yarlagadda S, Zhang W, Moon C, Bouquet E, Srinivasan S, Li C, Stokes DC, Naren AP. Personalized medicine in cystic fibrosis: genistein supplementation as a treatment option for patients with a rare S1045Y-CFTR mutation. Am J Physiol Lung Cell Mol Physiol 2016; 311:L364-74. [PMID: 27261451 DOI: 10.1152/ajplung.00134.2016] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Accepted: 05/26/2016] [Indexed: 11/22/2022] Open
Abstract
Cystic fibrosis (CF) is a life-shortening disease caused by the mutations that generate nonfunctional CF transmembrane conductance regulator (CFTR) protein. A rare serine-to-tyrosine (S1045Y) CFTR mutation was earlier reported to result in CF-associated fatality. We identified an African-American patient with the S1045Y mutation in CFTR, as well as a stop-codon mutation, who has a mild CF phenotype. The underlying mechanism of CF caused by S1045Y-CFTR has not been elucidated. In this study, we determined that S1045Y-CFTR exhibits twofold attenuated function compared with wild-type (WT)-CFTR. We report that serine-to-tyrosine mutation leads to increased tyrosine phosphorylation of S1045Y-CFTR, followed by recruitment and binding of E3-ubiquitin ligase c-cbl, resulting in enhanced ubiquitination and passage of S1045Y-CFTR in the endosome/lysosome degradative compartments. We demonstrate that inhibition of tyrosine phosphorylation partially rescues S1045Y-CFTR surface expression and function. Based on our findings, it could be suggested that consuming genistein (a tyrosine phosphorylation inhibitor) would likely ameliorate CF symptoms in individuals with S1045Y-CFTR, providing a unique personalized therapy for this rare CF mutation.
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Affiliation(s)
- Kavisha Arora
- Division of Pulmonary Medicine, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Sunitha Yarlagadda
- Division of Pulmonary Medicine, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Weiqiang Zhang
- Department of Physiology, University of Tennessee Health Science Center and University of Tennessee CF Care and Research Center at Le Bonheur Children's Hospital, Memphis, Tennessee; Department of Pediatrics, University of Tennessee Health Science Center and University of Tennessee CF Care and Research Center at Le Bonheur Children's Hospital, Memphis, Tennessee; and
| | - ChangSuk Moon
- Division of Pulmonary Medicine, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Erin Bouquet
- Division of Pulmonary Medicine, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Saumini Srinivasan
- Department of Physiology, University of Tennessee Health Science Center and University of Tennessee CF Care and Research Center at Le Bonheur Children's Hospital, Memphis, Tennessee; Department of Pediatrics, University of Tennessee Health Science Center and University of Tennessee CF Care and Research Center at Le Bonheur Children's Hospital, Memphis, Tennessee; and
| | - Chunying Li
- School of Medicine, Wayne State University, Detroit, Michigan
| | - Dennis C Stokes
- Department of Physiology, University of Tennessee Health Science Center and University of Tennessee CF Care and Research Center at Le Bonheur Children's Hospital, Memphis, Tennessee; Department of Pediatrics, University of Tennessee Health Science Center and University of Tennessee CF Care and Research Center at Le Bonheur Children's Hospital, Memphis, Tennessee; and
| | - Anjaparavanda P Naren
- Division of Pulmonary Medicine, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio;
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179
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Abstract
Activation of ion channels and pores are essential steps during regulated cell death. Channels and pores participate in execution of apoptosis, necroptosis and other forms of caspase-independent cell death. Within the program of regulated cell death, these channels are strategically located. Ion channels can shrink cells and drive them towards apoptosis, resulting in silent, i.e. immunologically unrecognized cell death. Alternatively, activation of channels can induce cell swelling, disintegration of the cell membrane, and highly immunogenic necrotic cell death. The underlying cell death pathways are not strictly separated as identical stimuli may induce cell shrinkage and apoptosis when applied at low strength, but may also cause cell swelling at pronounced stimulation, resulting in regulated necrosis. Nevertheless, the precise role of ion channels during regulated cell death is far from being understood, as identical channels may support regulated death in some cell types, but may cause cell proliferation, cancer development, and metastasis in others. Along this line, the phospholipid scramblase and Cl(-)/nonselective channel anoctamin 6 (ANO6) shows interesting features, as it participates in apoptotic cell death during lower levels of activation, thereby inducing cell shrinkage. At strong activation, e.g. by stimulation of purinergic P2Y7 receptors, it participates in pore formation, causes massive membrane blebbing, cell swelling, and membrane disintegration. The LRRC8 proteins deserve much attention as they were found to have a major role in volume regulation, apoptotic cell shrinkage and resistance towards anticancer drugs.
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Affiliation(s)
- Karl Kunzelmann
- Institut für Physiologie, Universität Regensburg, Universitätsstraße 31, 93053, Regensburg, Germany.
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180
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Liebl MP, Hoppe T. It's all about talking: two-way communication between proteasomal and lysosomal degradation pathways via ubiquitin. Am J Physiol Cell Physiol 2016; 311:C166-78. [PMID: 27225656 DOI: 10.1152/ajpcell.00074.2016] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Selective degradation of proteins requires a fine-tuned coordination of the two major proteolytic pathways, the ubiquitin-proteasome system (UPS) and autophagy. Substrate selection and proteolytic activity are defined by a plethora of regulatory cofactors influencing each other. Both proteolytic pathways are initiated by ubiquitylation to mark substrate proteins for degradation, although the size and/or topology of the modification are different. In this context E3 ubiquitin ligases, ensuring the covalent attachment of activated ubiquitin to the substrate, are of special importance. The regulation of E3 ligase activity, competition between different E3 ligases for binding E2 conjugation enzymes and substrates, as well as their interplay with deubiquitylating enzymes (DUBs) represent key events in the cross talk between the UPS and autophagy. The coordination between both degradation routes is further influenced by heat shock factors and ubiquitin-binding proteins (UBPs) such as p97, p62, or optineurin. Mutations in enzymes and ubiquitin-binding proteins or a general decline of both proteolytic systems during aging result in accumulation of damaged and aggregated proteins. Thus further mechanistic understanding of how UPS and autophagy communicate might allow therapeutic intervention especially against age-related diseases.
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Affiliation(s)
- Martina P Liebl
- Institute for Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Thorsten Hoppe
- Institute for Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
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181
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Gakhal AK, Jensen TJ, Bozoky Z, Roldan A, Lukacs GL, Forman-Kay J, Riordan JR, Sidhu SS. Development and characterization of synthetic antibodies binding to the cystic fibrosis conductance regulator. MAbs 2016; 8:1167-76. [PMID: 27185291 DOI: 10.1080/19420862.2016.1186320] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
Cystic fibrosis transmembrane conductance regulator (CFTR) is a chloride channel in the apical surface of epithelial cells in the airway and gastrointestinal tract, and mutation of CFTR is the underlying cause of cystic fibrosis. However, the precise molecular details of the structure and function of CFTR in native and disease states remains elusive and cystic fibrosis researchers are hindered by a lack of high specificity, high affinity binding reagents for use in structural and biological studies. Here, we describe a panel of synthetic antigen-binding fragments (Fabs) isolated from a phage-displayed library that are specific for intracellular domains of CFTR that include the nucleotide-binding domains (NBD1 and NBD2), the R-region, and the regulatory insertion loop of NBD1. Binding assays performed under conditions that promote the native fold of the protein demonstrated that all Fabs recognized full-length CFTR. However, only the NBD1-specific Fab recognized denatured CFTR by western blot, suggesting a conformational epitope requirement for the other Fabs. Surface plasmon resonance experiments showed that the R-region Fab binds with high affinity to both the phosphorylated and unphosphorylated R-region. In addition, NMR analysis of bound versus unbound R-region revealed a distinct conformational effect upon Fab binding. We further defined residues involved with antibody recognition using an overlapping peptide array. In summary, we describe methodology complementary to previous hybridoma-based efforts to develop antibody reagents to CFTR, and introduce a synthetic antibody panel to aid structural and biological studies.
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Affiliation(s)
- Amandeep K Gakhal
- a Donnelly Center for Cellular and Biomolecular Research , University of Toronto , Toronto , Ontario , Canada
| | - Timothy J Jensen
- b Department of Biochemistry and Biophysics , Cystic Fibrosis Treatment and Research Center, University of North Carolina , Chapel Hill , NC , USA
| | - Zoltan Bozoky
- c Program in Molecular Structure & Function , The Hospital for Sick Children , Toronto , ON , Canada.,d Department of Biochemistry , University of Toronto, Toronto , ON , Canada
| | - Ariel Roldan
- e Department of Physiology and Biochemistry , McGill University , Montreal , QC , Canada
| | - Gergely L Lukacs
- e Department of Physiology and Biochemistry , McGill University , Montreal , QC , Canada
| | - Julie Forman-Kay
- c Program in Molecular Structure & Function , The Hospital for Sick Children , Toronto , ON , Canada.,d Department of Biochemistry , University of Toronto, Toronto , ON , Canada
| | - John R Riordan
- b Department of Biochemistry and Biophysics , Cystic Fibrosis Treatment and Research Center, University of North Carolina , Chapel Hill , NC , USA
| | - Sachdev S Sidhu
- a Donnelly Center for Cellular and Biomolecular Research , University of Toronto , Toronto , Ontario , Canada
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182
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Veit G, Oliver K, Apaja PM, Perdomo D, Bidaud-Meynard A, Lin ST, Guo J, Icyuz M, Sorscher EJ, Hartman JL, Lukacs GL. Ribosomal Stalk Protein Silencing Partially Corrects the ΔF508-CFTR Functional Expression Defect. PLoS Biol 2016; 14:e1002462. [PMID: 27168400 PMCID: PMC4864299 DOI: 10.1371/journal.pbio.1002462] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Accepted: 04/14/2016] [Indexed: 01/05/2023] Open
Abstract
The most common cystic fibrosis (CF) causing mutation, deletion of phenylalanine 508 (ΔF508 or Phe508del), results in functional expression defect of the CF transmembrane conductance regulator (CFTR) at the apical plasma membrane (PM) of secretory epithelia, which is attributed to the degradation of the misfolded channel at the endoplasmic reticulum (ER). Deletion of phenylalanine 670 (ΔF670) in the yeast oligomycin resistance 1 gene (YOR1, an ABC transporter) of Saccharomyces cerevisiae phenocopies the ΔF508-CFTR folding and trafficking defects. Genome-wide phenotypic (phenomic) analysis of the Yor1-ΔF670 biogenesis identified several modifier genes of mRNA processing and translation, which conferred oligomycin resistance to yeast. Silencing of orthologues of these candidate genes enhanced the ΔF508-CFTR functional expression at the apical PM in human CF bronchial epithelia. Although knockdown of RPL12, a component of the ribosomal stalk, attenuated the translational elongation rate, it increased the folding efficiency as well as the conformational stability of the ΔF508-CFTR, manifesting in 3-fold augmented PM density and function of the mutant. Combination of RPL12 knockdown with the corrector drug, VX-809 (lumacaftor) restored the mutant function to ~50% of the wild-type channel in primary CFTRΔF508/ΔF508 human bronchial epithelia. These results and the observation that silencing of other ribosomal stalk proteins partially rescue the loss-of-function phenotype of ΔF508-CFTR suggest that the ribosomal stalk modulates the folding efficiency of the mutant and is a potential therapeutic target for correction of the ΔF508-CFTR folding defect. Reducing the rate of translational elongation by silencing ribosomal stalk proteins ameliorates the folding and stability defect of the cystic fibrosis mutant protein ΔF508-CFTR, partially restoring the plasma membrane chloride conductance. Cystic fibrosis (CF) is one of the most common autosomal recessive diseases in Caucasians. It is caused by mutations in the CF transmembrane conductance regulator (CFTR), which functions as an anion channel at the apical plasma membrane of secretory epithelia. The most common CF mutation, a deletion of the phenylalanine residue at position 508 (ΔF508), results in the channel misfolding and subsequent intracellular degradation. Our previous genome-wide phenotypic screens, using a yeast variant, have predicted modifier genes for ΔF508-CFTR biogenesis. Here, we show that silencing of one of these candidate genes, RPL12, a component of the ribosomal stalk, increased the folding and stabilization of ΔF508-CFTR, resulting in its increased plasma membrane expression and function. Our data suggest that reducing the translational elongation rate via RPL12 silencing can partially reverse the ΔF508-CFTR folding defect. Importantly, RPL12 silencing in combination with the corrector drug VX-809 (lumacaftor), increased the mutant function to 50% of the wild-type CFTR channel, suggesting that the ribosomal stalk perturbation may represent a therapeutic target for rescuing the ΔF508-CFTR biogenesis defect.
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Affiliation(s)
- Guido Veit
- Department of Physiology, McGill University, Montréal, Quebec, Canada
| | - Kathryn Oliver
- Department of Genetics, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Pirjo M. Apaja
- Department of Physiology, McGill University, Montréal, Quebec, Canada
| | - Doranda Perdomo
- Department of Physiology, McGill University, Montréal, Quebec, Canada
| | | | - Sheng-Ting Lin
- Department of Physiology, McGill University, Montréal, Quebec, Canada
| | - Jingyu Guo
- Department of Genetics, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Mert Icyuz
- Department of Genetics, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Eric J. Sorscher
- Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia, United States of America
| | - John L. Hartman
- Department of Genetics, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
- * E-mail: (JLH); (GLL)
| | - Gergely L. Lukacs
- Department of Physiology, McGill University, Montréal, Quebec, Canada
- Department of Biochemistry, McGill University, Montréal, Quebec, Canada
- Groupe de Recherche Axé sur la Structure des Protéines (GRASP), McGill University, Montréal, Quebec, Canada
- * E-mail: (JLH); (GLL)
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183
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The HSP70 co-chaperone DNAJC14 targets misfolded pendrin for unconventional protein secretion. Nat Commun 2016; 7:11386. [PMID: 27109633 PMCID: PMC4848490 DOI: 10.1038/ncomms11386] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 03/18/2016] [Indexed: 12/19/2022] Open
Abstract
Mutations in SLC26A4, which encodes pendrin, are responsible for hearing loss with an enlarged vestibular aqueduct and Pendred syndrome. The most prevalent mutation in East Asia is p.H723R (His723Arg), which leads to defects in protein folding and cell-surface expression. Here we show that H723R-pendrin can be rescued to the cell surface by an HSP70 co-chaperone DNAJC14-dependent unconventional trafficking pathway. Blockade of ER-to-Golgi transport or activation of ER stress signals induced Golgi-independent cell-surface expression of H723R-pendrin and restored its cell-surface Cl−/HCO3− exchange activity. Proteomic and short interfering RNA screenings with subsequent molecular analyses showed that Hsc70 and DNAJC14 are required for the unconventional trafficking of H723R-pendrin. Moreover, DNAJC14 upregulation was able to induce the unconventional cell-surface expression of H723R-pendrin. These results indicate that Hsc70 and DNAJC14 play central roles in ER stress-associated unconventional protein secretion and are potential therapeutic targets for diseases such as Pendred syndrome, which arise from transport defects of misfolded proteins. Mutations in pendrin, a plasma membrane transporter, lead to Pendred syndrome, which is associated with hearing loss. Here, Jung et al. show that cell-surface expression of a mutated form of pendrin can be restored by blocking ER-to-Golgi traffic and triggering a DNAJC14 dependent unconventional secretion pathway.
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184
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Pesce E, Gorrieri G, Sirci F, Napolitano F, Carrella D, Caci E, Tomati V, Zegarra-Moran O, di Bernardo D, Galietta LJV. Evaluation of a systems biology approach to identify pharmacological correctors of the mutant CFTR chloride channel. J Cyst Fibros 2016; 15:425-35. [PMID: 26971626 DOI: 10.1016/j.jcf.2016.02.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Revised: 01/21/2016] [Accepted: 02/22/2016] [Indexed: 11/28/2022]
Abstract
BACKGROUND Mistrafficking of CFTR protein caused by F508del, the most frequent mutation in cystic fibrosis (CF), can be corrected by cell incubation at low temperature, an effect that may be mediated by altered expression of proteostasis genes. METHODS To identify small molecules mimicking low temperature, we compared gene expression profiles of cells kept at 27°C with those previously generated from more than 1300 compounds. The resulting candidates were tested with a functional assay on a bronchial epithelial cell line. RESULTS We found that anti-inflammatory glucocorticoids, such as mometasone, budesonide, and fluticasone, increased mutant CFTR function. However, this activity was not confirmed in primary bronchial epithelial cells. Actually, glucocorticoids enhanced Na(+) absorption, an effect that could further impair mucociliary clearance in CF airways. CONCLUSIONS Our results suggest that rescue of F508del-CFTR by low temperature cannot be easily mimicked by small molecules and that compounds with closer transcriptional and functional effects need to be found.
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Affiliation(s)
- Emanuela Pesce
- Istituto Giannina Gaslini, via Gerolamo Gaslini 5, 16147 Genova, Italy
| | - Giulia Gorrieri
- Istituto Giannina Gaslini, via Gerolamo Gaslini 5, 16147 Genova, Italy
| | - Francesco Sirci
- Telethon Institute of Genetics and Medicine, Via Campi Flegrei 34, 80078 Pozzuoli, Italy
| | - Francesco Napolitano
- Telethon Institute of Genetics and Medicine, Via Campi Flegrei 34, 80078 Pozzuoli, Italy
| | - Diego Carrella
- Telethon Institute of Genetics and Medicine, Via Campi Flegrei 34, 80078 Pozzuoli, Italy
| | - Emanuela Caci
- Istituto Giannina Gaslini, via Gerolamo Gaslini 5, 16147 Genova, Italy
| | - Valeria Tomati
- Istituto Giannina Gaslini, via Gerolamo Gaslini 5, 16147 Genova, Italy
| | | | - Diego di Bernardo
- Telethon Institute of Genetics and Medicine, Via Campi Flegrei 34, 80078 Pozzuoli, Italy
| | - Luis J V Galietta
- Istituto Giannina Gaslini, via Gerolamo Gaslini 5, 16147 Genova, Italy
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185
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Lopes-Pacheco M, Sabirzhanova I, Rapino D, Morales MM, Guggino WB, Cebotaru L. Correctors Rescue CFTR Mutations in Nucleotide-Binding Domain 1 (NBD1) by Modulating Proteostasis. Chembiochem 2016; 17:493-505. [PMID: 26864378 DOI: 10.1002/cbic.201500620] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Indexed: 11/12/2022]
Abstract
We evaluated whether small molecule correctors could rescue four nucleotide-binding domain 1 (NBD1) mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene (A455E, S492F, ΔI507, and R560T). We first transfected Cos-7 cells (green monkey kidney cells) with A455E, S492F, ΔI507, or R560T and created HEK-293 (human embryonic kidney cells) cell lines stably expressing these CFTR mutations. The mutants showed lowered protein expression, instability at physiological temperature, and rapid degradation. After treatment with correctors CFFT-002, CFFT-003, C3, C4, and/or C18, the combination of C18+C4 showed the most correction and resulted in increased CFTR residing in the plasma membrane. We found a profound decrease in binding of CFTR to histone deacetylases (HDAC) 6 and 7 and heat shock proteins (Hsps) 27 and 40. Silencing Hsp27 or 40 rescued the mutants, but no additional amount of CFTR was rescued when both proteins were knocked down simultaneously. Thus, CFTR mutations in NBD1 can be rescued by a combination of correctors, and the treatment alters the interaction between mutated CFTR and the endoplasmic reticulum machinery.
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Affiliation(s)
- Miquéias Lopes-Pacheco
- Departments of Medicine and Physiology, Division of Gastroenterology and Hepatology, Johns Hopkins University, School of Medicine, Baltimore, MD, 21205, USA.,Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Av. Carlos Chagas Filho, 303 CCS/Bloco G/Sala G2-055, Rio de Janeiro, RJ, 21941-902, Brazil
| | - Inna Sabirzhanova
- Departments of Medicine and Physiology, Division of Gastroenterology and Hepatology, Johns Hopkins University, School of Medicine, Baltimore, MD, 21205, USA
| | - Daniele Rapino
- Departments of Medicine and Physiology, Division of Gastroenterology and Hepatology, Johns Hopkins University, School of Medicine, Baltimore, MD, 21205, USA
| | - Marcelo M Morales
- Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Av. Carlos Chagas Filho, 303 CCS/Bloco G/Sala G2-055, Rio de Janeiro, RJ, 21941-902, Brazil
| | - William B Guggino
- Departments of Medicine and Physiology, Division of Gastroenterology and Hepatology, Johns Hopkins University, School of Medicine, Baltimore, MD, 21205, USA
| | - Liudmila Cebotaru
- Departments of Medicine and Physiology, Division of Gastroenterology and Hepatology, Johns Hopkins University, School of Medicine, Baltimore, MD, 21205, USA.
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186
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Foo B, Williamson B, Young JC, Lukacs G, Shrier A. hERG quality control and the long QT syndrome. J Physiol 2016; 594:2469-81. [PMID: 26718903 DOI: 10.1113/jp270531] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 12/07/2015] [Indexed: 11/08/2022] Open
Abstract
Long-QT syndrome type-2 (LQT2) is characterized by reduced functional expression of the human ether-à-go-go related (hERG) gene product, resulting in impaired cardiac repolarization and predisposition to fatal arrhythmia. Previous studies have implicated abnormal trafficking of misfolded hERG as the primary mechanism of LQT2, with misfolding being caused by mutations in the hERG gene (inherited) or drug treatment (acquired). More generally, environmental and metabolic stresses present a constant challenge to the folding of proteins, including hERG, and must be countered by robust protein quality control (QC) systems. Disposal of partially unfolded yet functional plasma membrane (PM) proteins by protein QC contributes to the loss-of-function phenotype in various conformational diseases including cystic fibrosis (CF) and long-QT syndrome type-2 (LQT2). The prevalent view has been that the loss of PM expression of hERG is attributed to biosynthetic block by endoplasmic reticulum (ER) QC pathways. However, there is a growing appreciation for protein QC pathways acting at post-ER cellular compartments, which may contribute to conformational disease pathogenesis. This article will provide a background on the structure and cellular trafficking of hERG as well as inherited and acquired LQT2. We will review previous work on hERG ER QC and introduce the more novel view that there is a significant peripheral QC at the PM and peripheral cellular compartments. Particular attention is drawn to the unique role of the peripheral QC system in acquired LQT2. Understanding the QC process and players may provide targets for therapeutic intervention in dealing with LQT2.
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Affiliation(s)
- Brian Foo
- Department of Physiology, McGill University, Montréal, Québec, Canada, H3G 1Y6
| | - Brittany Williamson
- Department of Biochemistry, McGill University, Montréal, Québec, Canada, H3G 1Y6
| | - Jason C Young
- Department of Biochemistry, McGill University, Montréal, Québec, Canada, H3G 1Y6
| | - Gergely Lukacs
- Department of Physiology, McGill University, Montréal, Québec, Canada, H3G 1Y6
| | - Alvin Shrier
- Department of Physiology, McGill University, Montréal, Québec, Canada, H3G 1Y6
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187
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Abbattiscianni AC, Favia M, Mancini MT, Cardone RA, Guerra L, Monterisi S, Castellani S, Laselva O, Di Sole F, Conese M, Zaccolo M, Casavola V. Correctors of mutant CFTR enhance subcortical cAMP-PKA signaling through modulating ezrin phosphorylation and cytoskeleton organization. J Cell Sci 2016; 129:1128-40. [PMID: 26823603 DOI: 10.1242/jcs.177907] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Accepted: 01/21/2016] [Indexed: 12/28/2022] Open
Abstract
The most common mutation of the cystic fibrosis transmembrane regulator (CFTR) gene, F508del, produces a misfolded protein resulting in its defective trafficking to the cell surface and an impaired chloride secretion. Pharmacological treatments partially rescue F508del CFTR activity either directly by interacting with the mutant protein and/or indirectly by altering the cellular protein homeostasis. Here, we show that the phosphorylation of ezrin together with its binding to phosphatidylinositol-4,5-bisphosphate (PIP2) tethers the F508del CFTR to the actin cytoskeleton, stabilizing it on the apical membrane and rescuing the sub-membrane compartmentalization of cAMP and activated PKA. Both the small molecules trimethylangelicin (TMA) and VX-809, which act as 'correctors' for F508del CFTR by rescuing F508del-CFTR-dependent chloride secretion, also restore the apical expression of phosphorylated ezrin and actin organization and increase cAMP and activated PKA submembrane compartmentalization in both primary and secondary cystic fibrosis airway cells. Latrunculin B treatment or expression of the inactive ezrin mutant T567A reverse the TMA and VX-809-induced effects highlighting the role of corrector-dependent ezrin activation and actin re-organization in creating the conditions to generate a sub-cortical cAMP pool of adequate amplitude to activate the F508del-CFTR-dependent chloride secretion.
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Affiliation(s)
- Anna C Abbattiscianni
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari 70126, Italy
| | - Maria Favia
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari 70126, Italy
| | - Maria T Mancini
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari 70126, Italy
| | - Rosa A Cardone
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari 70126, Italy
| | - Lorenzo Guerra
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari 70126, Italy
| | - Stefania Monterisi
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3QX, UK
| | - Stefano Castellani
- Department of Medical and Surgical Sciences, University of Foggia, Foggia 71122, Italy
| | - Onofrio Laselva
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari 70126, Italy
| | - Francesca Di Sole
- Physiology and Pharmacology Department, Des Moines University, Des Moines, IA 50312, USA
| | - Massimo Conese
- Department of Medical and Surgical Sciences, University of Foggia, Foggia 71122, Italy
| | - Manuela Zaccolo
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3QX, UK
| | - Valeria Casavola
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari 70126, Italy
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188
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Chapter Five - Ubiquitination of Ion Channels and Transporters. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2016; 141:161-223. [DOI: 10.1016/bs.pmbts.2016.02.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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189
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Hegde RN, Parashuraman S, Iorio F, Ciciriello F, Capuani F, Carissimo A, Carrella D, Belcastro V, Subramanian A, Bounti L, Persico M, Carlile G, Galietta L, Thomas DY, Di Bernardo D, Luini A. Unravelling druggable signalling networks that control F508del-CFTR proteostasis. eLife 2015; 4. [PMID: 26701908 PMCID: PMC4749566 DOI: 10.7554/elife.10365] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2015] [Accepted: 11/26/2015] [Indexed: 01/17/2023] Open
Abstract
Cystic fibrosis (CF) is caused by mutations in CF transmembrane conductance regulator (CFTR). The most frequent mutation (F508del-CFTR) results in altered proteostasis, that is, in the misfolding and intracellular degradation of the protein. The F508del-CFTR proteostasis machinery and its homeostatic regulation are well studied, while the question whether ‘classical’ signalling pathways and phosphorylation cascades might control proteostasis remains barely explored. Here, we have unravelled signalling cascades acting selectively on the F508del-CFTR folding-trafficking defects by analysing the mechanisms of action of F508del-CFTR proteostasis regulator drugs through an approach based on transcriptional profiling followed by deconvolution of their gene signatures. Targeting multiple components of these signalling pathways resulted in potent and specific correction of F508del-CFTR proteostasis and in synergy with pharmacochaperones. These results provide new insights into the physiology of cellular proteostasis and a rational basis for developing effective pharmacological correctors of the F508del-CFTR defect. DOI:http://dx.doi.org/10.7554/eLife.10365.001 Cystic fibrosis is a genetic disease that commonly affects people of European descent. The condition is caused by mutations in the gene encoding a protein called “cystic fibrosis transmembrane conductance regulator” (or CFTR for short). CFTR forms a channel in the membrane of cells in the lungs that help transport salt across the membrane. Mutated versions of the protein are not as efficient at transporting salts, and eventually this damages the lung tissue. As the damage progresses, individuals become very vulnerable to bacterial infections that further damage the lungs and may eventually lead to death. One of the reasons CFTR mutations are harmful is that they cause the protein to fold up incorrectly and remain trapped inside the cell. Cells have quality control systems that recognize and destroy poorly folded proteins, and so only a few of the mutated CFTR proteins ever make it to the membrane to move salts. New therapies have been developed that improve folding of the protein and/or help the CFTR proteins that make it to the membrane work better. But more and better treatment options are needed. Hegde, Parashuraman et al. have now tested drugs that control how proteins fold and move to the membrane to see how they affect gene expression in cells with the most common cystic fibrosis-causing mutation. These drugs are known to improve the activity of the CFTR mutant, but do so too weakly to be of clinical interest. The experiments revealed that the expression of a few hundred genes was changed in response the drugs. Many of these genes were involved in major signalling pathways that control how CFTR is folded and trafficked within cells. Next, Hegde, Parashuraman et al. tested drugs that inhibit these signalling pathways to see if they improve salt handling in the mutated cells. The experiments demonstrated that these inhibitor drugs efficiently block the breakdown of misfolded CFTR, or boost the likelihood of CFTR making it to the membrane, helping improve salt trafficking in the cells. The inhibitors produced even better results when used in combination with a known CFTR-protecting drug. The results suggest that identifying and targeting signalling pathways involved in the folding, trafficking, and breakdown of CFTR may prove a promising way to treat cystic fibrosis. DOI:http://dx.doi.org/10.7554/eLife.10365.002
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Affiliation(s)
- Ramanath Narayana Hegde
- Institute of Protein Biochemistry, National Research Council, Naples, Italy.,Telethon Institute of Genetics and Medicine, Pozzuoli, Italy
| | - Seetharaman Parashuraman
- Institute of Protein Biochemistry, National Research Council, Naples, Italy.,Telethon Institute of Genetics and Medicine, Pozzuoli, Italy
| | - Francesco Iorio
- Telethon Institute of Genetics and Medicine, Pozzuoli, Italy
| | - Fabiana Ciciriello
- Telethon Institute of Genetics and Medicine, Pozzuoli, Italy.,Biology and Biotechnology Department "Charles Darwin", Sapienza University, Rome, Italy.,Department of Biochemistry, McIntyre Medical Sciences Building, McGill University, Montréal, Canada
| | | | | | - Diego Carrella
- Telethon Institute of Genetics and Medicine, Pozzuoli, Italy
| | | | - Advait Subramanian
- Institute of Protein Biochemistry, National Research Council, Naples, Italy
| | - Laura Bounti
- Institute of Protein Biochemistry, National Research Council, Naples, Italy
| | - Maria Persico
- Telethon Institute of Genetics and Medicine, Pozzuoli, Italy
| | - Graeme Carlile
- Department of Biochemistry, McIntyre Medical Sciences Building, McGill University, Montréal, Canada
| | - Luis Galietta
- U.O.C. Genetica Medica, Institute of Giannina Gaslini, Genova, Italy
| | - David Y Thomas
- Department of Biochemistry, McIntyre Medical Sciences Building, McGill University, Montréal, Canada
| | - Diego Di Bernardo
- Telethon Institute of Genetics and Medicine, Pozzuoli, Italy.,Department of Electrical Engineering and Information Technology, University of Naples Federico II, Naples, Italy
| | - Alberto Luini
- Institute of Protein Biochemistry, National Research Council, Naples, Italy.,Telethon Institute of Genetics and Medicine, Pozzuoli, Italy.,Istituto di Ricovero e Cura a Carattere Scientifico SDN, Naples, Italy
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190
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Zaman K, Sawczak V, Zaidi A, Butler M, Bennett D, Getsy P, Zeinomar M, Greenberg Z, Forbes M, Rehman S, Jyothikumar V, DeRonde K, Sattar A, Smith L, Corey D, Straub A, Sun F, Palmer L, Periasamy A, Randell S, Kelley TJ, Lewis SJ, Gaston B. Augmentation of CFTR maturation by S-nitrosoglutathione reductase. Am J Physiol Lung Cell Mol Physiol 2015; 310:L263-70. [PMID: 26637637 DOI: 10.1152/ajplung.00269.2014] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Accepted: 11/20/2015] [Indexed: 12/27/2022] Open
Abstract
S-nitrosoglutathione (GSNO) reductase regulates novel endogenous S-nitrosothiol signaling pathways, and mice deficient in GSNO reductase are protected from airways hyperreactivity. S-nitrosothiols are present in the airway, and patients with cystic fibrosis (CF) tend to have low S-nitrosothiol levels that may be attributed to upregulation of GSNO reductase activity. The present study demonstrates that 1) GSNO reductase activity is increased in the cystic fibrosis bronchial epithelial (CFBE41o(-)) cells expressing mutant F508del-cystic fibrosis transmembrane regulator (CFTR) compared with the wild-type CFBE41o(-) cells, 2) GSNO reductase expression level is increased in the primary human bronchial epithelial cells expressing mutant F508del-CFTR compared with the wild-type cells, 3) GSNO reductase colocalizes with cochaperone Hsp70/Hsp90 organizing protein (Hop; Stip1) in human airway epithelial cells, 4) GSNO reductase knockdown with siRNA increases the expression and maturation of CFTR and decreases Stip1 expression in human airway epithelial cells, 5) increased levels of GSNO reductase cause a decrease in maturation of CFTR, and 6) a GSNO reductase inhibitor effectively reverses the effects of GSNO reductase on CFTR maturation. These studies provide a novel approach to define the subcellular location of the interactions between Stip1 and GSNO reductase and the role of S-nitrosothiols in these interactions.
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Affiliation(s)
- Khalequz Zaman
- Pediatric Pulmonology Division, Department of Pediatrics, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Victoria Sawczak
- Pediatric Pulmonology Division, Department of Pediatrics, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Atiya Zaidi
- Pediatric Pulmonology Division, Department of Pediatrics, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Maya Butler
- Pediatric Respiratory Medicine, Department of Pediatrics, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Deric Bennett
- Pediatric Respiratory Medicine, Department of Pediatrics, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Paulina Getsy
- Pediatric Pulmonology Division, Department of Pediatrics, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Maryam Zeinomar
- Pediatric Pulmonology Division, Department of Pediatrics, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Zivi Greenberg
- Pediatric Respiratory Medicine, Department of Pediatrics, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Michael Forbes
- Pediatric Respiratory Medicine, Department of Pediatrics, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Shagufta Rehman
- W. M. Keck Center for Cellular Imaging, Department of Biology, University of Virginia, Charlottesville, Virginiga
| | - Vinod Jyothikumar
- W. M. Keck Center for Cellular Imaging, Department of Biology, University of Virginia, Charlottesville, Virginiga
| | - Kim DeRonde
- Pediatric Respiratory Medicine, Department of Pediatrics, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Abdus Sattar
- Department of Epidemiology and Biostatistics, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Laura Smith
- Pediatric Pulmonology Division, Department of Pediatrics, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Deborah Corey
- Pediatric Pulmonology Division, Department of Pediatrics, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Adam Straub
- Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Fei Sun
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan
| | - Lisa Palmer
- Pediatric Respiratory Medicine, Department of Pediatrics, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Ammasi Periasamy
- W. M. Keck Center for Cellular Imaging, Department of Biology, University of Virginia, Charlottesville, Virginiga
| | - Scott Randell
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Thomas J Kelley
- Pediatric Pulmonology Division, Department of Pediatrics, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Stephen J Lewis
- Pediatric Pulmonology Division, Department of Pediatrics, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Benjamin Gaston
- Pediatric Pulmonology Division, Department of Pediatrics, Case Western Reserve University School of Medicine, Cleveland, Ohio; Pediatric Pulmonology Division, Rainbow Babies and Children's Hospital, Cleveland, Ohio
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191
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Ehrhardt A, Chung WJ, Pyle LC, Wang W, Nowotarski K, Mulvihill CM, Ramjeesingh M, Hong J, Velu SE, Lewis HA, Atwell S, Aller S, Bear CE, Lukacs GL, Kirk KL, Sorscher EJ. Channel Gating Regulation by the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) First Cytosolic Loop. J Biol Chem 2015; 291:1854-1865. [PMID: 26627831 DOI: 10.1074/jbc.m115.704809] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Indexed: 11/06/2022] Open
Abstract
In this study, we present data indicating a robust and specific domain interaction between the cystic fibrosis transmembrane conductance regulator (CFTR) first cytosolic loop (CL1) and nucleotide binding domain 1 (NBD1) that allows ion transport to proceed in a regulated fashion. We used co-precipitation and ELISA to establish the molecular contact and showed that binding kinetics were not altered by the common clinical mutation F508del. Both intrinsic ATPase activity and CFTR channel gating were inhibited severely by CL1 peptide, suggesting that NBD1/CL1 binding is a crucial requirement for ATP hydrolysis and channel function. In addition to cystic fibrosis, CFTR dysregulation has been implicated in the pathogenesis of prevalent diseases such as chronic obstructive pulmonary disease, acquired rhinosinusitis, pancreatitis, and lethal secretory diarrhea (e.g. cholera). On the basis of clinical relevance of the CFTR as a therapeutic target, a cell-free drug screen was established to identify modulators of NBD1/CL1 channel activity independent of F508del CFTR and pharmacologic rescue. Our findings support a targetable mechanism of CFTR regulation in which conformational changes in the NBDs cause reorientation of transmembrane domains via interactions with CL1 and result in channel gating.
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Affiliation(s)
- Annette Ehrhardt
- From the Gregory Fleming James Cystic Fibrosis Research Center and; the Department of Pediatrics, Emory University, Atlanta, Georgia 30322
| | - W Joon Chung
- From the Gregory Fleming James Cystic Fibrosis Research Center and; Departments of Neurobiology
| | - Louise C Pyle
- From the Gregory Fleming James Cystic Fibrosis Research Center and
| | - Wei Wang
- Cellular, Integrative, and Developmental Biology
| | | | - Cory M Mulvihill
- the Hospital for Sick Children Research Institute, Toronto M5G 1X8, Canada
| | | | - Jeong Hong
- From the Gregory Fleming James Cystic Fibrosis Research Center and; Cellular, Integrative, and Developmental Biology
| | - Sadanandan E Velu
- Chemistry, University of Alabama at Birmingham, Birmingham, Alabama 35294
| | - Hal A Lewis
- Bristol-Myers Squibb, Princeton, New Jersey 08543
| | | | - Steve Aller
- From the Gregory Fleming James Cystic Fibrosis Research Center and; Pharmacology, and
| | - Christine E Bear
- the Hospital for Sick Children Research Institute, Toronto M5G 1X8, Canada,; the Departments of Biochemistry and; Physiology, University of Toronto, Toronto M5G 1X8, Canada, and
| | - Gergely L Lukacs
- the Department of Physiology, McGill University, Montreal H3G 1Y6, Canada
| | - Kevin L Kirk
- From the Gregory Fleming James Cystic Fibrosis Research Center and; Cellular, Integrative, and Developmental Biology
| | - Eric J Sorscher
- the Department of Pediatrics, Emory University, Atlanta, Georgia 30322,.
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192
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Pankow S, Bamberger C, Calzolari D, Martínez-Bartolomé S, Lavallée-Adam M, Balch WE, Yates JR. ∆F508 CFTR interactome remodelling promotes rescue of cystic fibrosis. Nature 2015; 528:510-6. [PMID: 26618866 PMCID: PMC4826614 DOI: 10.1038/nature15729] [Citation(s) in RCA: 183] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Accepted: 09/14/2015] [Indexed: 12/16/2022]
Abstract
Deletion of phenylalanine 508 of the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) is the major cause of Cystic Fibrosis (CF), one of the most common inherited childhood diseases. The mutated CFTR anion channel is not fully glycosylated and shows minimal activity in bronchial epithelial cells of CF patients. Low temperature or inhibition of histone deacetylases (HDACi) can partially rescue ΔF508 CFTR cellular processing defects and function. A favorable change of ΔF508 CFTR protein-protein interactions was proposed as mechanism of rescue, however CFTR interactome dynamics during temperature-shift and HDACi rescue are unknown. Here, we report the first comprehensive analysis of the wt and ΔF508 CFTR interactome and its dynamics during temperature shift and HDACi. By using a novel deep proteomic analysis method (CoPIT), we identified 638 individual high-confidence CFTR interactors and discovered a mutation-specific interactome, which is extensively remodeled upon rescue. Detailed analysis of the interactome remodeling identified key novel interactors, whose loss promoted enhanced CFTR channel function in primary CF epithelia or which were critical for normal CFTR biogenesis. Our results demonstrate that global remodeling of ΔF508 CFTR interactions is crucial for rescue, and provide comprehensive insight into the molecular disease mechanisms of CF caused by deletion of F508.
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Affiliation(s)
- Sandra Pankow
- Department of Chemical Physiology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, USA
| | - Casimir Bamberger
- Department of Chemical Physiology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, USA
| | - Diego Calzolari
- Department of Chemical Physiology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, USA
| | - Salvador Martínez-Bartolomé
- Department of Chemical Physiology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, USA
| | - Mathieu Lavallée-Adam
- Department of Chemical Physiology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, USA
| | - William E Balch
- Department of Cell Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, USA
| | - John R Yates
- Department of Chemical Physiology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, USA
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193
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Farinha CM, Matos P. Repairing the basic defect in cystic fibrosis - one approach is not enough. FEBS J 2015; 283:246-64. [PMID: 26416076 DOI: 10.1111/febs.13531] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Revised: 09/21/2015] [Accepted: 09/23/2015] [Indexed: 12/16/2022]
Abstract
Cystic fibrosis has attracted much attention in recent years due to significant advances in the pharmacological targeting of the basic defect underlying this recessive disorder: the deficient functional expression of mutant cystic fibrosis transmembrane conductance regulator (CFTR) chloride channels at the apical membrane of epithelial cells. However, increasing evidence points to the reduced efficacy of single treatments, thus reinforcing the need to combine several therapeutic strategies to effectively target the multiple basic defect(s). Protein-repair therapies that use potentiators (activating membrane-located CFTR) or correctors (promoting the relocation of intracellular-retained trafficking mutants of CFTR) in frequent mutations such as F508del and G551D have been put forward and made their way to the clinic with moderate to good efficiency. However, alternative (or additional) approaches targeting the membrane stability of mutant proteins, or correcting the cellular phenotype through a direct effect upon other ion channels (affecting the overall electrolyte transport or simply promoting alternative chloride transport) or targeting less frequent mutations (splicing variants, for example), have been proposed and tested in the field of cystic fibrosis (CF). Here, we cover the different strategies that rely on novel findings concerning the CFTR interactome and signalosome through which it might be possible to further influence the cellular trafficking and post-translational modification machinery (to increase rescued CFTR abundance and membrane stability). We also highlight the new data on strategies aiming at the regulation of sodium absorption or to increase chloride transport through alternative channels. The development and implementation of these complementary approaches will pave the way to combinatorial therapeutic strategies with increased benefit to CF patients.
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Affiliation(s)
- Carlos M Farinha
- BioISI - Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, Portugal
| | - Paulo Matos
- BioISI - Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, Portugal.,Department of Human Genetics, National Health Institute 'Dr. Ricardo Jorge', Lisboa, Portugal
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194
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Ghosh A, Boucher RC, Tarran R. Airway hydration and COPD. Cell Mol Life Sci 2015; 72:3637-52. [PMID: 26068443 PMCID: PMC4567929 DOI: 10.1007/s00018-015-1946-7] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Revised: 05/26/2015] [Accepted: 06/01/2015] [Indexed: 02/07/2023]
Abstract
Chronic obstructive pulmonary disease (COPD) is one of the prevalent causes of worldwide mortality and encompasses two major clinical phenotypes, i.e., chronic bronchitis (CB) and emphysema. The most common cause of COPD is chronic tobacco inhalation. Research focused on the chronic bronchitic phenotype of COPD has identified several pathological processes that drive disease initiation and progression. For example, the lung's mucociliary clearance (MCC) system performs the critical task of clearing inhaled pathogens and toxic materials from the lung. MCC efficiency is dependent on: (1) the ability of apical plasma membrane ion channels such as the cystic fibrosis transmembrane conductance regulator (CFTR) and the epithelial Na(+) channel (ENaC) to maintain airway hydration; (2) ciliary beating; and (3) appropriate rates of mucin secretion. Each of these components is impaired in CB and likely contributes to the mucus stasis/accumulation seen in CB patients. This review highlights the cellular components responsible for maintaining MCC and how this process is disrupted following tobacco exposure and with CB. We shall also discuss existing therapeutic strategies for the treatment of chronic bronchitis and how components of the MCC can be used as biomarkers for the evaluation of tobacco or tobacco-like-product exposure.
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Affiliation(s)
- Arunava Ghosh
- Cystic Fibrosis Center/Marsico Lung Institute and the Department of Cell Biology and Physiology, The University of North Carolina, 7102 Marsico Hall, Chapel Hill, NC, 27599-7248, USA
| | - R C Boucher
- Cystic Fibrosis Center/Marsico Lung Institute and the Department of Cell Biology and Physiology, The University of North Carolina, 7102 Marsico Hall, Chapel Hill, NC, 27599-7248, USA
| | - Robert Tarran
- Cystic Fibrosis Center/Marsico Lung Institute and the Department of Cell Biology and Physiology, The University of North Carolina, 7102 Marsico Hall, Chapel Hill, NC, 27599-7248, USA.
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195
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De Stefano D, Villella VR, Esposito S, Tosco A, Sepe A, De Gregorio F, Salvadori L, Grassia R, Leone CA, De Rosa G, Maiuri MC, Pettoello-Mantovani M, Guido S, Bossi A, Zolin A, Venerando A, Pinna LA, Mehta A, Bona G, Kroemer G, Maiuri L, Raia V. Restoration of CFTR function in patients with cystic fibrosis carrying the F508del-CFTR mutation. Autophagy 2015; 10:2053-74. [PMID: 25350163 PMCID: PMC4502695 DOI: 10.4161/15548627.2014.973737] [Citation(s) in RCA: 123] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Restoration of BECN1/Beclin 1-dependent autophagy and depletion of SQSTM1/p62 by genetic manipulation or autophagy-stimulatory proteostasis regulators, such as cystamine, have positive effects on mouse models of human cystic fibrosis (CF). These measures rescue the functional expression of the most frequent pathogenic CFTR mutant, F508del, at the respiratory epithelial surface and reduce lung inflammation in CftrF508del homozygous mice. Cysteamine, the reduced form of cystamine, is an FDA-approved drug. Here, we report that oral treatment with cysteamine greatly reduces the mortality rate and improves the phenotype of newborn mice bearing the F508del-CFTR mutation. Cysteamine was also able to increase the plasma membrane expression of the F508del-CFTR protein in nasal epithelial cells from F508del homozygous CF patients, and these effects persisted for 24 h after cysteamine withdrawal. Importantly, this cysteamine effect after washout was further sustained by the sequential administration of epigallocatechin gallate (EGCG), a green tea flavonoid, both in vivo, in mice, and in vitro, in primary epithelial cells from CF patients. In a pilot clinical trial involving 10 F508del-CFTR homozygous CF patients, the combination of cysteamine and EGCG restored BECN1, reduced SQSTM1 levels and improved CFTR function from nasal epithelial cells in vivo, correlating with a decrease of chloride concentrations in sweat, as well as with a reduction of the abundance of TNF/TNF-alpha (tumor necrosis factor) and CXCL8 (chemokine [C-X-C motif] ligand 8) transcripts in nasal brushing and TNF and CXCL8 protein levels in the sputum. Altogether, these results suggest that optimal schedules of cysteamine plus EGCG might be used for the treatment of CF caused by the F508del-CFTR mutation.
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Key Words
- BECN1/Beclin 1, autophagy-related
- CF, cystic fibrosis
- CFTR
- CFTR, cystic fibrosis transmembrane conductance regulator
- CHX, cycloheximide
- CSNK2, casein kinase 2
- CXCL2, chemokine (C-X-C motif) ligand 2
- CXCL8, chemokine (C-X-C motif) ligand 8
- EGCG, epigallocatechin gallate
- FEV, forced expiratory volume
- PM, plasma membrane
- RPD, rectal potential difference
- SQSTM1, sequestosome 1
- TGM2, transglutaminase 2
- TNF, tumor necrosis factor
- autophagy
- cysteamine
- cystic fibrosis
- epigallocatechin gallate
- sweat chloride
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Affiliation(s)
- Daniela De Stefano
- a European Institute for Research in Cystic Fibrosis; Division of Genetics and Cell Biology; San Raffaele Scientific Institute ; Milan , Italy
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196
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Zhang Y, O'Brien WG, Zhao Z, Lee CC. 5'-adenosine monophosphate mediated cooling treatment enhances ΔF508-Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) stability in vivo. J Biomed Sci 2015; 22:72. [PMID: 26335336 PMCID: PMC4559075 DOI: 10.1186/s12929-015-0178-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Accepted: 08/20/2015] [Indexed: 12/26/2022] Open
Abstract
Background Gene mutations that produce misprocessed proteins are linked to many human disorders. Interestingly, some misprocessed proteins retained their biological function when stabilized by low temperature treatment of cultured cells in vitro. Here we investigate whether low temperature treatment in vivo can rescue misfolded proteins by applying 5’-AMP mediated whole body cooling to a Cystic Fibrosis (CF) mouse model carrying a mutant cystic fibrosis transmembrane conductance regulator (CFTR) with a deletion of the phenylalanine residue in position 508 (ΔF508-CFTR). Low temperature treatment of cultured cells was previously shown to be able to alleviate the processing defect of ΔF508-CFTR, enhancing its plasma membrane localization and its function in mediating chloride ion transport. Results Here, we report that whole body cooling enhanced the retention of ΔF508-CFTR in intestinal epithelial cells. Functional analysis based on β-adrenergic dependent salivary secretion and post-natal mortality rate revealed a moderate but significant improvement in treated compared with untreated CF mice. Conclusions Our findings demonstrate that temperature sensitive processing of mutant proteins can be responsive to low temperature treatment in vivo.
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Affiliation(s)
- Yueqiang Zhang
- Department of Biochemistry and Molecular Biology, University of Texas Health Science Center at Houston, Houston, TX, 77030, USA
| | - William G O'Brien
- Department of Biochemistry and Molecular Biology, University of Texas Health Science Center at Houston, Houston, TX, 77030, USA
| | - Zhaoyang Zhao
- Department of Biochemistry and Molecular Biology, University of Texas Health Science Center at Houston, Houston, TX, 77030, USA
| | - Cheng Chi Lee
- Department of Biochemistry and Molecular Biology, University of Texas Health Science Center at Houston, Houston, TX, 77030, USA.
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197
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Jai Y, Shah K, Bridges RJ, Bradbury NA. Evidence against resveratrol as a viable therapy for the rescue of defective ΔF508 CFTR. Biochim Biophys Acta Gen Subj 2015; 1850:2377-84. [PMID: 26342647 DOI: 10.1016/j.bbagen.2015.08.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 08/10/2015] [Accepted: 08/31/2015] [Indexed: 01/23/2023]
Abstract
BACKGROUND Resveratrol, a natural phenolic compound, has been reported to rescue mutant ΔF508 CFTR in expression systems and primary epithelial cells. Although this implies a therapeutic benefit to patients with CF, investigations were performed using resveratrol concentrations greatly in excess of those achievable in plasma. We evaluated the efficacy of resveratrol as a CFTR corrector in relevant primary airway cells, using physiologically achievable resveratrol concentrations. METHODS Cells expressing wt or ΔF508 CFTR were exposed to chronic or acute resveratrol. CFTR mRNA and protein expression were monitored. The effects of resveratrol on primary ΔF508 human airway cells were evaluated by equivalent current analysis using modified Ussing chambers. RESULTS Consistent with previously published data in heterologous expression systems, high doses of resveratrol increased CFTR expression; however physiologically relevant concentrations were without effect. In contrast to heterologous expression systems, resveratrol was unable to increase mutant CFTR channel activity in primary airway cells. Elevated amiloride-sensitive currents, indicative of sodium transport and characteristically elevated in CF airway cells, were also unaffected by resveratrol. CONCLUSIONS High concentrations of resveratrol can increase CFTR mRNA and protein in some cell types. In addition, acute resveratrol exposure can stimulate CFTR mediated chloride secretion, probably by increasing cellular cAMP levels. Resveratrol at physiologically achievable levels yielded no benefit in primary ΔF508 airway cells, either in terms of amiloride-sensitive currents of CFTR currents. GENERAL SIGNIFICANCE Taken together, our results do not support the use of resveratrol supplements as a therapy for patients with cystic fibrosis. It is possible that further modifications of the resveratrol backbone would yield a more efficacious compound.
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Affiliation(s)
- Ying Jai
- Department of Physiology and Biophysics, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL, USA
| | - Kalpit Shah
- Department of Physiology and Biophysics, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL, USA
| | - Robert J Bridges
- Department of Physiology and Biophysics, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL, USA
| | - Neil A Bradbury
- Department of Physiology and Biophysics, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL, USA.
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198
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Wang F, Yang Y, Wang Z, Zhou J, Fan B, Chen Z. A Critical Role of Lyst-Interacting Protein5, a Positive Regulator of Multivesicular Body Biogenesis, in Plant Responses to Heat and Salt Stresses. PLANT PHYSIOLOGY 2015; 169:497-511. [PMID: 26229051 PMCID: PMC4577394 DOI: 10.1104/pp.15.00518] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Accepted: 07/30/2015] [Indexed: 05/19/2023]
Abstract
Multivesicular bodies (MVBs) are unique endosomes containing vesicles in the lumen and play critical roles in many cellular processes. We have recently shown that Arabidopsis (Arabidopsis thaliana) Lyst-Interacting Protein5 (LIP5), a positive regulator of the Suppressor of K(+) Transport Growth Defect1 (SKD1) AAA ATPase in MVB biogenesis, is a critical target of the mitogen-activated protein kinases MPK3 and MPK6 and plays an important role in the plant immune system. In this study, we report that the LIP5-regulated MVB pathway also plays a critical role in plant responses to abiotic stresses. Disruption of LIP5 causes compromised tolerance to both heat and salt stresses. The critical role of LIP5 in plant tolerance to abiotic stresses is dependent on its ability to interact with Suppressor of K(+) Transport Growth Defect1. When compared with wild-type plants, lip5 mutants accumulate increased levels of ubiquitinated protein aggregates and NaCl under heat and salt stresses, respectively. Further analysis using fluorescent dye and MVB markers reveals that abiotic stress increases the formation of endocytic vesicles and MVBs in a largely LIP5-dependent manner. LIP5 is also required for the salt-induced increase of intracellular reactive oxygen species, which have been implicated in signaling of salt stress responses. Basal levels of LIP5 phosphorylation by MPKs and the stability of LIP5 are elevated by salt stress, and mutation of MPK phosphorylation sites in LIP5 reduces the stability and compromises the ability to complement the lip5 salt-sensitive mutant phenotype. These results collectively indicate that the MVB pathway is positively regulated by pathogen/stress-responsive MPK3/6 through LIP5 phosphorylation and plays a critical role in broad plant responses to biotic and abiotic stresses.
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Affiliation(s)
- Fei Wang
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907-2054 (F.W., Z.W., J.Z., B.F., Z.C.); andDepartment of Horticulture, Zijingang Campus, Zhejiang University, Hangzhou 310058, China (Y.Y., J.Z., Z.C.)
| | - Yan Yang
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907-2054 (F.W., Z.W., J.Z., B.F., Z.C.); andDepartment of Horticulture, Zijingang Campus, Zhejiang University, Hangzhou 310058, China (Y.Y., J.Z., Z.C.)
| | - Zhe Wang
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907-2054 (F.W., Z.W., J.Z., B.F., Z.C.); andDepartment of Horticulture, Zijingang Campus, Zhejiang University, Hangzhou 310058, China (Y.Y., J.Z., Z.C.)
| | - Jie Zhou
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907-2054 (F.W., Z.W., J.Z., B.F., Z.C.); andDepartment of Horticulture, Zijingang Campus, Zhejiang University, Hangzhou 310058, China (Y.Y., J.Z., Z.C.)
| | - Baofang Fan
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907-2054 (F.W., Z.W., J.Z., B.F., Z.C.); andDepartment of Horticulture, Zijingang Campus, Zhejiang University, Hangzhou 310058, China (Y.Y., J.Z., Z.C.)
| | - Zhixiang Chen
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907-2054 (F.W., Z.W., J.Z., B.F., Z.C.); andDepartment of Horticulture, Zijingang Campus, Zhejiang University, Hangzhou 310058, China (Y.Y., J.Z., Z.C.)
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199
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Vertii A, Zimmerman W, Ivshina M, Doxsey S. Centrosome-intrinsic mechanisms modulate centrosome integrity during fever. Mol Biol Cell 2015; 26:3451-63. [PMID: 26269579 PMCID: PMC4591690 DOI: 10.1091/mbc.e15-03-0158] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Accepted: 08/04/2015] [Indexed: 12/23/2022] Open
Abstract
The centrosome is critical for cell division. Heat stress (HS) causes degradation of all centrosome substructures by centrosome-bound proteasomes. HS-activated degradation is centrosome specific and can be rescued by targeting Hsp70 to the centrosome. Centrosome inactivation is a physiological event, as centrosomes in leukocytes of febrile patients are disrupted. The centrosome is critical for cell division, ciliogenesis, membrane trafficking, and immunological synapse function. The immunological synapse is part of the immune response, which is often accompanied by fever/heat stress (HS). Here we provide evidence that HS causes deconstruction of all centrosome substructures primarily through degradation by centrosome-associated proteasomes. This renders the centrosome nonfunctional. Heat-activated degradation is centrosome selective, as other nonmembranous organelles (midbody, kinetochore) and membrane-bounded organelles (mitochondria) remain largely intact. Heat-induced centrosome inactivation was rescued by targeting Hsp70 to the centrosome. In contrast, Hsp70 excluded from the centrosome via targeting to membranes failed to rescue, as did chaperone inactivation. This indicates that there is a balance between degradation and chaperone rescue at the centrosome after HS. This novel mechanism of centrosome regulation during fever contributes to immunological synapse formation. Heat-induced centrosome inactivation is a physiologically relevant event, as centrosomes in leukocytes of febrile patients are disrupted.
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Affiliation(s)
- Anastassiia Vertii
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605
| | - Wendy Zimmerman
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605
| | - Maria Ivshina
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605
| | - Stephen Doxsey
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605
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200
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Sinha C, Zhang W, Moon CS, Actis M, Yarlagadda S, Arora K, Woodroofe K, Clancy JP, Lin S, Ziady AG, Frizzell R, Fujii N, Naren AP. Capturing the Direct Binding of CFTR Correctors to CFTR by Using Click Chemistry. Chembiochem 2015; 16:2017-22. [PMID: 26227551 DOI: 10.1002/cbic.201500123] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Indexed: 12/26/2022]
Abstract
Cystic fibrosis (CF) is a lethal genetic disease caused by the loss or dysfunction of the CF transmembrane conductance regulator (CFTR) channel. F508del is the most prevalent mutation of the CFTR gene and encodes a protein defective in folding and processing. VX-809 has been reported to facilitate the folding and trafficking of F508del-CFTR and augment its channel function. The mechanism of action of VX-809 has been poorly understood. In this study, we sought to answer a fundamental question underlying the mechanism of VX-809: does it bind CFTR directly in order to exert its action? We synthesized two VX-809 derivatives, ALK-809 and SUL-809, that possess an alkyne group and retain the rescue capacity of VX-809. By using Cu(I) -catalyzed click chemistry, we provide evidence that the VX-809 derivatives bind CFTR directly in vitro and in cells. Our findings will contribute to the elucidation of the mechanism of action of CFTR correctors and the design of more potent therapeutics to combat CF.
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Affiliation(s)
- Chandrima Sinha
- Division of Pulmonary Medicine, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, USA.,Department of Physiology, University of Tennessee Health Science Center, Memphis, TN, 38163, USA
| | - Weiqiang Zhang
- Department of Physiology, University of Tennessee Health Science Center, Memphis, TN, 38163, USA.,Department of Pediatrics, University of Tennessee Health Science Center, Memphis, TN, 38103, USA
| | - Chang Suk Moon
- Division of Pulmonary Medicine, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, USA
| | - Marcelo Actis
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA
| | - Sunitha Yarlagadda
- Division of Pulmonary Medicine, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, USA
| | - Kavisha Arora
- Division of Pulmonary Medicine, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, USA
| | - Koryse Woodroofe
- Division of Pulmonary Medicine, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, USA
| | - John P Clancy
- Division of Pulmonary Medicine, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, USA
| | - Songbai Lin
- Division of Pulmonary Medicine, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, USA
| | - Assem G Ziady
- Division of Pulmonary Medicine, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, USA
| | - Raymond Frizzell
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15261, USA
| | - Naoaki Fujii
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA
| | - Anjaparavanda P Naren
- Division of Pulmonary Medicine, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, USA. .,Department of Physiology, University of Tennessee Health Science Center, Memphis, TN, 38163, USA.
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