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McDonald EF, Kim M, Olson JA, Meiler J, Plate L. Proteostasis Landscapes of Selective versus Poorly Responsive CFTR Variants Reveals Structural Vulnerabilities to Correction. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.10.602964. [PMID: 39026768 PMCID: PMC11257600 DOI: 10.1101/2024.07.10.602964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/20/2024]
Abstract
Cystic Fibrosis (CF) is a lethal genetic disorder caused by variants in CF transmembrane conductance regulator (CFTR). Many disease variants are treatable with corrector compounds, which enhance the folding and trafficking of CFTR. However, correctors fail to elicit a response for every CFTR variant. Approximately 3% of persons with CF harbor poorly responsive CFTR variants. Here, we reveal that a group of poorly responsive variants overlap with selectively responsive variants in a critical domain interface (nucleotide-binding domain 1/intracellular loop 4 - NBD1/ICL4). Affinity purification mass spectrometry proteomics was used to profile the protein homeostasis (proteostasis) changes of CFTR variants during corrector treatment to assess modulated interactions with protein folding and maturation pathways. Responsive variant interactions converged on similar proteostasis pathways during correction. In contrast, poorly responsive variants subtly diverged, revealing a partial restoration of protein quality control surveillance and a capacity to correct some mutations. Computational structural modeling showed that corrector VX-445 failed to confer enough NBD1 stability to poorly responsive variants. NBD1 secondary stabilizing mutations rescued poorly responsive variants, revealing structural vulnerabilities in NBD1 required for treating poor responders. Our study provides a framework for discerning the underlying protein quality control and structural defects of CFTR variants not reached with existing drugs. These insights can help expand therapeutics to all susceptible CFTR variants to enhance personalized medicine efforts.
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Affiliation(s)
- Eli Fritz McDonald
- Department of Chemistry, Vanderbilt University, Nashville, TN 37235, USA
- Center for Structural Biology, Vanderbilt University, Nashville, TN 37240, USA
| | - Minsoo Kim
- Department of Chemistry, Vanderbilt University, Nashville, TN 37235, USA
- Chemical and Physical Biology Program, Vanderbilt University, Nashville, TN 37240, USA
| | - John A Olson
- Department of Chemistry, Vanderbilt University, Nashville, TN 37235, USA
- Chemical and Physical Biology Program, Vanderbilt University, Nashville, TN 37240, USA
| | - Jens Meiler
- Department of Chemistry, Vanderbilt University, Nashville, TN 37235, USA
- Center for Structural Biology, Vanderbilt University, Nashville, TN 37240, USA
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37240, USA
- Institute for Drug Discovery, Leipzig University, Leipzig, SAC 04103, Germany
| | - Lars Plate
- Department of Chemistry, Vanderbilt University, Nashville, TN 37235, USA
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37240, USA
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
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Anglès F, Gupta V, Wang C, Balch WE. COPII cage assembly factor Sec13 integrates information flow regulating endomembrane function in response to human variation. Sci Rep 2024; 14:10160. [PMID: 38698045 PMCID: PMC11065896 DOI: 10.1038/s41598-024-60687-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Accepted: 04/26/2024] [Indexed: 05/05/2024] Open
Abstract
How information flow is coordinated for managing transit of 1/3 of the genome through endomembrane pathways by the coat complex II (COPII) system in response to human variation remains an enigma. By examining the interactome of the COPII cage-assembly component Sec13, we show that it is simultaneously associated with multiple protein complexes that facilitate different features of a continuous program of chromatin organization, transcription, translation, trafficking, and degradation steps that are differentially sensitive to Sec13 levels. For the trafficking step, and unlike other COPII components, reduction of Sec13 expression decreased the ubiquitination and degradation of wild-type (WT) and F508del variant cargo protein cystic fibrosis transmembrane conductance regulator (CFTR) leading to a striking increase in fold stability suggesting that the events differentiating export from degradation are critically dependent on COPII cage assembly at the ER Golgi intermediate compartment (ERGIC) associated recycling and degradation step linked to COPI exchange. Given Sec13's multiple roles in protein complex assemblies that change in response to its expression, we suggest that Sec13 serves as an unanticipated master regulator coordinating information flow from the genome to the proteome to facilitate spatial covariant features initiating and maintaining design and function of membrane architecture in response to human variation.
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Affiliation(s)
- Frédéric Anglès
- Department of Molecular Medicine, The Scripps Research Institute, 10550 North Torrey Pines Rd, La Jolla, CA, 92037, USA
| | - Vijay Gupta
- Department of Molecular Medicine, The Scripps Research Institute, 10550 North Torrey Pines Rd, La Jolla, CA, 92037, USA
| | - Chao Wang
- Department of Molecular Medicine, The Scripps Research Institute, 10550 North Torrey Pines Rd, La Jolla, CA, 92037, USA
| | - William E Balch
- Department of Molecular Medicine, The Scripps Research Institute, 10550 North Torrey Pines Rd, La Jolla, CA, 92037, USA.
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3
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Farinha CM, Santos L, Ferreira JF. Cell type-specific regulation of CFTR trafficking-on the verge of progress. Front Cell Dev Biol 2024; 12:1338892. [PMID: 38505263 PMCID: PMC10949533 DOI: 10.3389/fcell.2024.1338892] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Accepted: 02/21/2024] [Indexed: 03/21/2024] Open
Abstract
Trafficking of the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) protein is a complex process that starts with its biosynthesis and folding in the endoplasmic reticulum. Exit from the endoplasmic reticulum (ER) is coupled with the acquisition of a compact structure that can be processed and traffic through the secretory pathway. Once reaching its final destination-the plasma membrane, CFTR stability is regulated through interaction with multiple protein partners that are involved in its post-translation modification, connecting the channel to several signaling pathways. The complexity of the process is further boosted when analyzed in the context of the airway epithelium. Recent advances have characterized in detail the different cell types that compose the surface epithelium and shifted the paradigm on which cells express CFTR and on their individual and combined contribution to the total expression (and function) of this chloride/bicarbonate channel. Here we review CFTR trafficking and its relationship with the knowledge on the different cell types of the airway epithelia. We explore the crosstalk between these two areas and discuss what is still to be clarified and how this can be used to develop more targeted therapies for CF.
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Affiliation(s)
- Carlos M. Farinha
- Faculty of Sciences, BioISI—Biosystems and Integrative Sciences Institute, University of Lisboa, Lisboa, Portugal
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Dang T, Yu J, Yu Y, Jiang J, Shi Y, Yu S, Peng C, Min X, Xiong Y, Long P, Zhou W, Dai D. GPX4 inhibits apoptosis of thyroid cancer cells through regulating the FKBP8/Bcl-2 axis. Cancer Biomark 2024; 39:349-360. [PMID: 38250761 DOI: 10.3233/cbm-230220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2024]
Abstract
GPX4 has attracted much attention as a key molecule of cell ferroptosis, but its role in cell apoptosis is rarely reported, and its role in apoptosis of thyroid cancer (TC) cell has not been reported. The analysis of TCGA database showed that both GPX4 and FKBP8 were highly expressed in TC tumor tissues; The expression of GPX4 and FKBP8 were positively correlated. The immunohistochemical analysis further confirmed that GPX4 and FKBP8 were highly expressed in TC tumor tissues. In addition, the high expression of GPX4 and FKBP8 were both significantly correlated with the poor prognosis of TC. Silencing GPX4 significantly inhibited the proliferation, induced apoptosis of TC cells, and reduced tumor growth in mice. The co-immunoprecipitation assay revealed a physical interaction between GPX4 and FKBP8 observed in the TC cells. Knockdown of FKBP8 significantly inhibited the proliferation and induced apoptosis of TC cells. Rescue experiments suggested that knockdown of FKBP8 could reverse the strengthens of cell proliferation and apoptosis and the higher expression of FKBP8 and Bcl-2 caused by overexpression of GPX4. Our results suggest that the GPX4/FKBP8/Bcl-2 axis promotes TC development by inhibiting TC cell apoptosis, which provides potential molecular targets for TC therapeutic strategies.
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Affiliation(s)
- Tianfeng Dang
- Jiangxi Otorhinolaryngology-Head and Neck Surgery Institute, Department of Otorhinolaryngology-Head and Neck Surgery, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, Jiangxi, China
- Medical Innovation Center, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, Jiangxi, China
- Jiangxi Otorhinolaryngology-Head and Neck Surgery Institute, Department of Otorhinolaryngology-Head and Neck Surgery, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, Jiangxi, China
| | - Jieqing Yu
- Jiangxi Otorhinolaryngology-Head and Neck Surgery Institute, Department of Otorhinolaryngology-Head and Neck Surgery, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, Jiangxi, China
- Jiangxi Otorhinolaryngology-Head and Neck Surgery Institute, Department of Otorhinolaryngology-Head and Neck Surgery, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, Jiangxi, China
| | - Yanqing Yu
- Department of Pathology, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, Jiangxi, China
| | - Junjie Jiang
- Jiangxi Otorhinolaryngology-Head and Neck Surgery Institute, Department of Otorhinolaryngology-Head and Neck Surgery, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, Jiangxi, China
| | - Yang Shi
- Jiangxi Otorhinolaryngology-Head and Neck Surgery Institute, Department of Otorhinolaryngology-Head and Neck Surgery, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, Jiangxi, China
| | - Simin Yu
- Jiangxi Otorhinolaryngology-Head and Neck Surgery Institute, Department of Otorhinolaryngology-Head and Neck Surgery, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, Jiangxi, China
| | - Congli Peng
- Jiangxi Otorhinolaryngology-Head and Neck Surgery Institute, Department of Otorhinolaryngology-Head and Neck Surgery, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, Jiangxi, China
| | - Xiang Min
- Jiangxi Otorhinolaryngology-Head and Neck Surgery Institute, Department of Otorhinolaryngology-Head and Neck Surgery, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, Jiangxi, China
| | - Yuanping Xiong
- Jiangxi Otorhinolaryngology-Head and Neck Surgery Institute, Department of Otorhinolaryngology-Head and Neck Surgery, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, Jiangxi, China
| | - Ping Long
- Jiangxi Otorhinolaryngology-Head and Neck Surgery Institute, Department of Otorhinolaryngology-Head and Neck Surgery, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, Jiangxi, China
| | - Wensheng Zhou
- Jiangxi Otorhinolaryngology-Head and Neck Surgery Institute, Department of Otorhinolaryngology-Head and Neck Surgery, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, Jiangxi, China
| | - Daofeng Dai
- Jiangxi Otorhinolaryngology-Head and Neck Surgery Institute, Department of Otorhinolaryngology-Head and Neck Surgery, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, Jiangxi, China
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Kim M, McDonald EF, Sabusap CMP, Timalsina B, Joshi D, Hong JS, Rab A, Sorscher EJ, Plate L. Elexacaftor/VX-445-mediated CFTR interactome remodeling reveals differential correction driven by mutation-specific translational dynamics. J Biol Chem 2023; 299:105242. [PMID: 37690692 PMCID: PMC10579539 DOI: 10.1016/j.jbc.2023.105242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 08/30/2023] [Accepted: 09/04/2023] [Indexed: 09/12/2023] Open
Abstract
Cystic fibrosis (CF) is one of the most prevalent lethal genetic diseases with over 2000 identified mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. Pharmacological chaperones such as lumacaftor (VX-809), tezacaftor (VX-661), and elexacaftor (VX-445) treat mutation-induced defects by stabilizing CFTR and are called correctors. These correctors improve proper folding and thus facilitate processing and trafficking to increase the amount of functional CFTR on the cell surface. Yet, CFTR variants display differential responses to each corrector. Here, we report that variants P67L and L206W respond similarly to VX-809 but divergently to VX-445 with P67L exhibiting little rescue when treated with VX-445. We investigate the underlying cellular mechanisms of how CFTR biogenesis is altered by correctors in these variants. Affinity purification-mass spectrometry multiplexed with isobaric tandem mass tags was used to quantify CFTR protein-protein interaction changes between variants P67L and L206W. VX-445 facilitates unique proteostasis factor interactions especially in translation, folding, and degradation pathways in a CFTR variant-dependent manner. A number of these interacting proteins knocked down by siRNA, such as ribosomal subunit proteins, moderately rescued fully glycosylated P67L. Importantly, these knockdowns sensitize P67L to VX-445 and further enhance the trafficking correction of this variant. Partial inhibition of protein translation also mildly sensitizes P67L CFTR to VX-445 correction, supporting a role for translational dynamics in the rescue mechanism of VX-445. Our results provide a better understanding of VX-445 biological mechanism of action and reveal cellular targets that may sensitize nonresponsive CFTR variants to known and available correctors.
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Affiliation(s)
- Minsoo Kim
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, USA; Program in Chemical and Physical Biology, Vanderbilt University, Nashville, Tennessee, USA
| | - Eli Fritz McDonald
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, USA
| | | | - Bibek Timalsina
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, USA
| | - Disha Joshi
- Department of Pediatrics, Emory University, Atlanta, Georgia, USA
| | - Jeong S Hong
- Department of Pediatrics, Emory University, Atlanta, Georgia, USA
| | - Andras Rab
- Department of Pediatrics, Emory University, Atlanta, Georgia, USA
| | - Eric J Sorscher
- Department of Pediatrics, Emory University, Atlanta, Georgia, USA
| | - Lars Plate
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, USA; Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA; Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA.
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Zuo L, Kuo WT, Cao F, Chanez-Paredes SD, Zeve D, Mannam P, Jean-François L, Day A, Vallen Graham W, Sweat YY, Shashikanth N, Breault DT, Turner JR. Tacrolimus-binding protein FKBP8 directs myosin light chain kinase-dependent barrier regulation and is a potential therapeutic target in Crohn's disease. Gut 2023; 72:870-881. [PMID: 35537812 PMCID: PMC9977574 DOI: 10.1136/gutjnl-2021-326534] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 04/11/2022] [Indexed: 12/17/2022]
Abstract
OBJECTIVE Intestinal barrier loss is a Crohn's disease (CD) risk factor. This may be related to increased expression and enzymatic activation of myosin light chain kinase 1 (MLCK1), which increases intestinal paracellular permeability and correlates with CD severity. Moreover, preclinical studies have shown that MLCK1 recruitment to cell junctions is required for tumour necrosis factor (TNF)-induced barrier loss as well as experimental inflammatory bowel disease progression. We sought to define mechanisms of MLCK1 recruitment and to target this process pharmacologically. DESIGN Protein interactions between FK506 binding protein 8 (FKBP8) and MLCK1 were assessed in vitro. Transgenic and knockout intestinal epithelial cell lines, human intestinal organoids, and mice were used as preclinical models. Discoveries were validated in biopsies from patients with CD and control subjects. RESULTS MLCK1 interacted specifically with the tacrolimus-binding FKBP8 PPI domain. Knockout or dominant negative FKBP8 expression prevented TNF-induced MLCK1 recruitment and barrier loss in vitro. MLCK1-FKBP8 binding was blocked by tacrolimus, which reversed TNF-induced MLCK1-FKBP8 interactions, MLCK1 recruitment and barrier loss in vitro and in vivo. Biopsies of patient with CD demonstrated increased numbers of MLCK1-FKBP8 interactions at intercellular junctions relative to control subjects. CONCLUSION Binding to FKBP8, which can be blocked by tacrolimus, is required for MLCK1 recruitment to intercellular junctions and downstream events leading to immune-mediated barrier loss. The observed increases in MLCK1 activity, MLCK1 localisation at cell junctions and perijunctional MLCK1-FKBP8 interactions in CD suggest that targeting this process may be therapeutic in human disease. These new insights into mechanisms of disease-associated barrier loss provide a critical foundation for therapeutic exploitation of FKBP8-MLCK1 interactions.
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Affiliation(s)
- Li Zuo
- Anhui Medical University, Hefei, Anhui, China
- Department of Pathology, Harvard Medical School, Boston, Massachusetts, USA
- Laboratory of Mucosal Barrier Pathobiology, Department of Pathology, Brigham and Women's Hospital, Boston, Massachusetts, USA
| | - Wei-Ting Kuo
- Department of Pathology, Harvard Medical School, Boston, Massachusetts, USA
- Laboratory of Mucosal Barrier Pathobiology, Department of Pathology, Brigham and Women's Hospital, Boston, Massachusetts, USA
- Graduate Institute of Oral Biology, National Taiwan University, Taipei, Taiwan
| | - Feng Cao
- Laboratory of Mucosal Barrier Pathobiology, Department of Pathology, Brigham and Women's Hospital, Boston, Massachusetts, USA
- Department of Otorhinolaryngology Head and Neck Surgery, Second People's Hospital of Hefei, Hefei, Anhui, China
| | - Sandra D Chanez-Paredes
- Department of Pathology, Harvard Medical School, Boston, Massachusetts, USA
- Laboratory of Mucosal Barrier Pathobiology, Department of Pathology, Brigham and Women's Hospital, Boston, Massachusetts, USA
| | - Daniel Zeve
- Pediatrics, Boston Children's Hospital, Boston, Massachusetts, USA
- Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA
| | - Prabhath Mannam
- Pediatrics, Boston Children's Hospital, Boston, Massachusetts, USA
| | - Léa Jean-François
- Laboratory of Mucosal Barrier Pathobiology, Department of Pathology, Brigham and Women's Hospital, Boston, Massachusetts, USA
| | - Anne Day
- Laboratory of Mucosal Barrier Pathobiology, Department of Pathology, Brigham and Women's Hospital, Boston, Massachusetts, USA
| | - W Vallen Graham
- Department of Pathology, The University of Chicago, Chicago, Illinois, USA
| | - Yan Y Sweat
- Department of Pathology, Harvard Medical School, Boston, Massachusetts, USA
- Laboratory of Mucosal Barrier Pathobiology, Department of Pathology, Brigham and Women's Hospital, Boston, Massachusetts, USA
| | - Nitesh Shashikanth
- Department of Pathology, Harvard Medical School, Boston, Massachusetts, USA
- Laboratory of Mucosal Barrier Pathobiology, Department of Pathology, Brigham and Women's Hospital, Boston, Massachusetts, USA
| | - David T Breault
- Pediatrics, Boston Children's Hospital, Boston, Massachusetts, USA
- Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA
| | - Jerrold R Turner
- Department of Pathology, Harvard Medical School, Boston, Massachusetts, USA
- Laboratory of Mucosal Barrier Pathobiology, Department of Pathology, Brigham and Women's Hospital, Boston, Massachusetts, USA
- Department of Pathology, The University of Chicago, Chicago, Illinois, USA
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Jenness MK, Tayengwa R, Bate GA, Tapken W, Zhang Y, Pang C, Murphy AS. Loss of Multiple ABCB Auxin Transporters Recapitulates the Major twisted dwarf 1 Phenotypes in Arabidopsis thaliana. FRONTIERS IN PLANT SCIENCE 2022; 13:840260. [PMID: 35528937 PMCID: PMC9069160 DOI: 10.3389/fpls.2022.840260] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 03/16/2022] [Indexed: 06/14/2023]
Abstract
FK506-BINDING PROTEIN 42/TWISTED DWARF 1 (FKBP42/TWD1) directly regulates cellular trafficking and activation of multiple ATP-BINDING CASSETTE (ABC) transporters from the ABCB and ABCC subfamilies. abcb1 abcb19 double mutants exhibit remarkable phenotypic overlap with twd1 including severe dwarfism, stamen elongation defects, and compact circinate leaves; however, twd1 mutants exhibit greater loss of polar auxin transport and additional helical twisting of roots, inflorescences, and siliques. As abcc1 abcc2 mutants do not exhibit any visible phenotypes and TWD1 does not interact with PIN or AUX1/LAX auxin transporters, loss of function of other ABCB auxin transporters is hypothesized to underly the remaining morphological phenotypes. Here, gene expression, mutant analyses, pharmacological inhibitor studies, auxin transport assays, and direct auxin quantitations were used to determine the relative contributions of loss of other reported ABCB auxin transporters (4, 6, 11, 14, 20, and 21) to twd1 phenotypes. From these analyses, the additional reduction in plant height and the twisted inflorescence, root, and silique phenotypes observed in twd1 compared to abcb1 abcb19 result from loss of ABCB6 and ABCB20 function. Additionally, abcb6 abcb20 root twisting exhibited the same sensitivity to the auxin transport inhibitor 1-napthalthalamic acid as twd1 suggesting they are the primary contributors to these auxin-dependent organ twisting phenotypes. The lack of obvious phenotypes in higher order abcb4 and abcb21 mutants suggests that the functional loss of these transporters does not contribute to twd1 root or shoot twisting. Analyses of ABCB11 and ABCB14 function revealed capacity for auxin transport; however, their activities are readily outcompeted by other substrates, suggesting alternate functions in planta, consistent with a spectrum of relative substrate affinities among ABCB transporters. Overall, the results presented here suggest that the ABCB1/19 and ABCB6/20 pairs represent the primary long-distance ABCB auxin transporters in Arabidopsis and account for all reported twd1 morphological phenotypes. Other ABCB transporters appear to participate in highly localized auxin streams or mobilize alternate transport substrates.
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Affiliation(s)
- Mark K. Jenness
- Department of Plant Science and Landscape Architecture, University of Maryland, College Park, MD, United States
| | - Reuben Tayengwa
- Department of Plant Science and Landscape Architecture, University of Maryland, College Park, MD, United States
| | - Gabrielle A. Bate
- Department of Plant Science and Landscape Architecture, University of Maryland, College Park, MD, United States
| | - Wiebke Tapken
- Department of Plant Science and Landscape Architecture, University of Maryland, College Park, MD, United States
| | - Yuqin Zhang
- School of Plant Sciences and Food Security, Tel Aviv University, Tel Aviv, Israel
| | - Changxu Pang
- Department of Plant Science and Landscape Architecture, University of Maryland, College Park, MD, United States
| | - Angus S. Murphy
- Department of Plant Science and Landscape Architecture, University of Maryland, College Park, MD, United States
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Regulation of ClC-2 Chloride Channel Proteostasis by Molecular Chaperones: Correction of Leukodystrophy-Associated Defect. Int J Mol Sci 2021; 22:ijms22115859. [PMID: 34070744 PMCID: PMC8197790 DOI: 10.3390/ijms22115859] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 05/23/2021] [Accepted: 05/26/2021] [Indexed: 11/16/2022] Open
Abstract
The ClC-2 channel plays a critical role in maintaining ion homeostasis in the brain and the testis. Loss-of-function mutations in the ClC-2-encoding human CLCN2 gene are linked to the white matter disease leukodystrophy. Clcn2-deficient mice display neuronal myelin vacuolation and testicular degeneration. Leukodystrophy-causing ClC-2 mutant channels are associated with anomalous proteostasis manifesting enhanced endoplasmic reticulum (ER)-associated degradation. The molecular nature of the ER quality control system for ClC-2 protein remains elusive. In mouse testicular tissues and Leydig cells, we demonstrated that endogenous ClC-2 co-existed in the same protein complex with the molecular chaperones heat shock protein 90β (Hsp90β) and heat shock cognate protein (Hsc70), as well as the associated co-chaperones Hsp70/Hsp90 organizing protein (HOP), activator of Hsp90 ATPase homolog 1 (Aha1), and FK506-binding protein 8 (FKBP8). Further biochemical analyses revealed that the Hsp90β-Hsc70 chaperone/co-chaperone system promoted mouse and human ClC-2 protein biogenesis. FKBP8 additionally facilitated membrane trafficking of ClC-2 channels. Interestingly, treatment with the Hsp90-targeting small molecule 17-allylamino-17-demethoxygeldanamycin (17-AAG) substantially boosted ClC-2 protein expression. Also, 17-AAG effectively increased both total and cell surface protein levels of leukodystrophy-causing loss-of-function ClC-2 mutant channels. Our findings highlight the therapeutic potential of 17-AAG in correcting anomalous ClC-2 proteostasis associated with leukodystrophy.
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Karatas E, Raymond AA, Leon C, Dupuy JW, Di-Tommaso S, Senant N, Collardeau-Frachon S, Ruiz M, Lachaux A, Saltel F, Bouchecareilh M. Hepatocyte proteomes reveal the role of protein disulfide isomerase 4 in alpha 1-antitrypsin deficiency. JHEP Rep 2021; 3:100297. [PMID: 34151245 PMCID: PMC8192868 DOI: 10.1016/j.jhepr.2021.100297] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 04/06/2021] [Accepted: 04/09/2021] [Indexed: 11/25/2022] Open
Abstract
Background & Aims A single point mutation in the Z-variant of alpha 1-antitrypsin (Z-AAT) alone can lead to both a protein folding and trafficking defect, preventing its exit from the endoplasmic reticulum (ER), and the formation of aggregates that are retained as inclusions within the ER of hepatocytes. These defects result in a systemic AAT deficiency (AATD) that causes lung disease, whereas the ER-retained aggregates can induce severe liver injury in patients with ZZ-AATD. Unfortunately, therapeutic approaches are still limited and liver transplantation represents the only curative treatment option. To overcome this limitation, a better understanding of the molecular basis of ER aggregate formation could provide new strategies for therapeutic intervention. Methods Our functional and omics approaches here based on human hepatocytes from patients with ZZ-AATD have enabled the identification and characterisation of the role of the protein disulfide isomerase (PDI) A4/ERP72 in features of AATD-mediated liver disease. Results We report that 4 members of the PDI family (PDIA4, PDIA3, P4HB, and TXNDC5) are specifically upregulated in ZZ-AATD liver samples from adult patients. Furthermore, we show that only PDIA4 knockdown or alteration of its activity by cysteamine treatment can promote Z-AAT secretion and lead to a marked decrease in Z aggregates. Finally, detailed analysis of the Z-AAT interactome shows that PDIA4 silencing provides a more conducive environment for folding of the Z mutant, accompanied by reduction of Z-AAT-mediated oxidative stress, a feature of AATD-mediated liver disease. Conclusions PDIA4 is involved in AATD-mediated liver disease and thus represents a therapeutic target for inhibition by drugs such as cysteamine. PDI inhibition therefore represents a potential therapeutic approach for treatment of AATD. Lay summary Protein disulfide isomerase (PDI) family members, and particularly PDIA4, are upregulated and involved in alpha 1-antitrypsin deficiency (AATD)-mediated liver disease in adults. PDI inhibition upon cysteamine treatment leads to improvements in features of AATD and hence represents a therapeutic approach for treatment of AATD-mediated liver disease. PDIA4 is upregulated and involved in alpha 1-antitrypsin deficiency (AATD)-mediated liver disease in adults. Knockdown of PDIA4 by siRNA or inhibition upon cysteamine treatment leads to improvements in features of AATD. RNA interference against PDIA4 or cysteamine represent approaches for treatment of AATD-mediated liver disease.
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Key Words
- AAT, alpha 1-antitrypsin
- AATD, alpha 1-antitrypsin deficiency
- Alpha 1-antitrypsin deficiency
- CF, cystic fibrosis
- CFTR, cystic fibrosis transmembrane conductance regulator
- Cysteamine
- ER, endoplasmic reticulum
- FFPE, formalin-fixed paraffin-embedded
- FKBP10, FK506-binding protein (FKBP) isoform 10
- HCC, hepatocellular carcinoma
- IHC, immunohistochemistry
- IP, immunoprecipitation
- Liver damage
- NHK, null Hong Kong variant of AAT
- P4HB, prolyl 4-hydroxylase subunit beta/PDIA1
- PDI, protein disulfide isomerase
- PDIA3, protein disulfide isomerase family A member 3/ERP57
- PDIA4
- PDIA4, protein disulfide isomerase family A member 4/ERP70/ERP72
- PDIi, PDI inhibitors
- Protein disulfide isomerase
- ROS, reactive oxygen species
- SURF4, proteins Surfeit 4
- Scr, scramble
- TRX, thioredoxin
- TXNDC5, thioredoxin domain containing 5/PDIA15
- Treatment
- WT, wild-type
- Z-AAT, alpha 1-antitrypsin Z variant
- ZZ, homozygosis for the Z mutant allele
- siRNA, small RNA interference
- ΔF508-CFTR, most common mutation of CFTR, which deletes phenylalanine508
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Affiliation(s)
- Esra Karatas
- University of Bordeaux, CNRS, INSERM, BaRITOn, U1053, Bordeaux, France
| | - Anne-Aurélie Raymond
- University of Bordeaux, CNRS, INSERM, BaRITOn, U1053, Bordeaux, France.,Oncoprot, University of Bordeaux, INSERM, TBM-Core, UMS 3427, US 5, Bordeaux, France
| | - Céline Leon
- University of Bordeaux, CNRS, INSERM, BaRITOn, U1053, Bordeaux, France
| | | | - Sylvaine Di-Tommaso
- Oncoprot, University of Bordeaux, INSERM, TBM-Core, UMS 3427, US 5, Bordeaux, France
| | - Nathalie Senant
- Plateforme d'histopathologie, TBM-Core US 005, Bordeaux, France
| | - Sophie Collardeau-Frachon
- Department of Pathology, Hôpital Femme Mère Enfant, Hospices Civils de Lyon, Lyon, France.,Hépatologie, Gastroentérologie et Nutrition pédiatriques, Centre de référence de l'atrésie des voies biliaires et cholestases génétiques, Hôpital Femme Mère Enfant, Hospices Civils de Lyon, Lyon, France.,Faculté de Médecine Lyon-Est, Université Claude Bernard Lyon 1, Lyon, France
| | - Mathias Ruiz
- Hépatologie, Gastroentérologie et Nutrition pédiatriques, Centre de référence de l'atrésie des voies biliaires et cholestases génétiques, Hôpital Femme Mère Enfant, Hospices Civils de Lyon, Lyon, France.,European Reference Network on Hepatological Diseases (ERN RARE-LIVER), Hamburg, Germany.,Faculté de Médecine Lyon-Est, Université Claude Bernard Lyon 1, Lyon, France
| | - Alain Lachaux
- Hépatologie, Gastroentérologie et Nutrition pédiatriques, Centre de référence de l'atrésie des voies biliaires et cholestases génétiques, Hôpital Femme Mère Enfant, Hospices Civils de Lyon, Lyon, France.,European Reference Network on Hepatological Diseases (ERN RARE-LIVER), Hamburg, Germany.,Faculté de Médecine Lyon-Est, Université Claude Bernard Lyon 1, Lyon, France
| | - Frédéric Saltel
- University of Bordeaux, CNRS, INSERM, BaRITOn, U1053, Bordeaux, France.,Oncoprot, University of Bordeaux, INSERM, TBM-Core, UMS 3427, US 5, Bordeaux, France
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10
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Geisler M, Hegedűs T. A twist in the ABC: regulation of ABC transporter trafficking and transport by FK506-binding proteins. FEBS Lett 2020; 594:3986-4000. [PMID: 33125703 DOI: 10.1002/1873-3468.13983] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 10/02/2020] [Accepted: 10/15/2020] [Indexed: 01/07/2023]
Abstract
Post-transcriptional regulation of ATP-binding cassette (ABC) proteins has been so far shown to encompass protein phosphorylation, maturation, and ubiquitination. Yet, recent accumulating evidence implicates FK506-binding proteins (FKBPs), a type of peptidylprolyl cis-trans isomerase (PPIase) proteins, in ABC transporter regulation. In this perspective article, we summarize current knowledge on ABC transporter regulation by FKBPs, which seems to be conserved over kingdoms and ABC subfamilies. We uncover striking functional similarities but also differences between regulatory FKBP-ABC modules in plants and mammals. We dissect a PPIase- and HSP90-dependent and independent impact of FKBPs on ABC biogenesis and transport activity. We propose and discuss a putative new mode of transient ABC transporter regulation by cis-trans isomerization of X-prolyl bonds.
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Affiliation(s)
- Markus Geisler
- Department of Biology, University of Fribourg, Switzerland
| | - Tamás Hegedűs
- Department of Biophysics and Radiation Biology, Semmelweis University, Budapest, Hungary
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11
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Amaral MD. How to determine the mechanism of action of CFTR modulator compounds: A gateway to theranostics. Eur J Med Chem 2020; 210:112989. [PMID: 33190956 DOI: 10.1016/j.ejmech.2020.112989] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 11/02/2020] [Accepted: 11/02/2020] [Indexed: 12/12/2022]
Abstract
The greatest challenge of 21st century biology is to fully understand mechanisms of disease to drive new approaches and medical innovation. Parallel to this is the huge biomedical endeavour of treating people through personalized medicine. Until now all CFTR modulator drugs that have entered clinical trials have been genotype-dependent. An emerging alternative is personalized/precision medicine in CF, i.e., to determine whether rare CFTR mutations respond to existing (or novel) CFTR modulator drugs by pre-assessing them directly on patient's tissues ex vivo, an approach also now termed theranostics. To administer the right drug to the right person it is essential to understand how drugs work, i.e., to know their mechanism of action (MoA), so as to predict their applicability, not just in certain mutations but also possibly in other diseases that share the same defect/defective pathway. Moreover, an understanding the MoA of a drug before it is tested in clinical trials is the logical path to drug discovery and can increase its chance for success and hence also approval. In conclusion, the most powerful approach to determine the MoA of a compound is to understand the underlying biology. Novel large datasets of intervenients in most biological processes, namely those emerging from the post-genomic era tools, are available and should be used to help in this task.
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Affiliation(s)
- Margarida D Amaral
- BioISI - Biosystems & Integrative Sciences Institute, Lisboa, Faculty of Sciences, University of Lisboa, Portugal.
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12
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Hao P, Xia J, Liu J, Di Donato M, Pakula K, Bailly A, Jasinski M, Geisler M. Auxin-transporting ABC transporters are defined by a conserved D/E-P motif regulated by a prolylisomerase. J Biol Chem 2020; 295:13094-13105. [PMID: 32699109 PMCID: PMC7489919 DOI: 10.1074/jbc.ra120.014104] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 07/16/2020] [Indexed: 12/15/2022] Open
Abstract
The plant hormone auxin must be transported throughout plants in a cell-to-cell manner to affect its various physiological functions. ABCB transporters are critical for this polar auxin distribution, but the regulatory mechanisms controlling their function is not fully understood. The auxin transport activity of ABCB1 was suggested to be regulated by a physical interaction with FKBP42/Twisted Dwarf1 (TWD1), a peptidylprolyl cis-trans isomerase (PPIase), but all attempts to demonstrate such a PPIase activity by TWD1 have failed so far. By using a structure-based approach, we identified several surface-exposed proline residues in the nucleotide binding domain and linker of Arabidopsis ABCB1, mutations of which do not alter ABCB1 protein stability or location but do affect its transport activity. P1008 is part of a conserved signature D/E-P motif that seems to be specific for auxin-transporting ABCBs, which we now refer to as ATAs. Mutation of the acidic residue also abolishes auxin transport activity by ABCB1. All higher plant ABCBs for which auxin transport has been conclusively proven carry this conserved motif, underlining its predictive potential. Introduction of this D/E-P motif into malate importer, ABCB14, increases both its malate and its background auxin transport activity, suggesting that this motif has an impact on transport capacity. The D/E-P1008 motif is also important for ABCB1-TWD1 interactions and activation of ABCB1-mediated auxin transport by TWD1. In summary, our data imply a new function for TWD1 acting as a putative activator of ABCB-mediated auxin transport by cis-trans isomerization of peptidyl-prolyl bonds.
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Affiliation(s)
- Pengchao Hao
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Jian Xia
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Jie Liu
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Martin Di Donato
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Konrad Pakula
- Department of Plant Molecular Physiology, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland; NanoBioMedical Centre, Adam Mickiewicz University, Poznan, Poland
| | - Aurélien Bailly
- Institute for Plant and Microbial Biology, Zurich, Switzerland
| | - Michal Jasinski
- Department of Plant Molecular Physiology, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland; Department of Biochemistry and Biotechnology, Poznan University of Life Sciences, Poznan, Poland
| | - Markus Geisler
- Department of Biology, University of Fribourg, Fribourg, Switzerland.
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13
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Regulation of CFTR Biogenesis by the Proteostatic Network and Pharmacological Modulators. Int J Mol Sci 2020; 21:ijms21020452. [PMID: 31936842 PMCID: PMC7013518 DOI: 10.3390/ijms21020452] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Revised: 01/06/2020] [Accepted: 01/08/2020] [Indexed: 12/14/2022] Open
Abstract
Cystic fibrosis (CF) is the most common lethal inherited disease among Caucasians in North America and a significant portion of Europe. The disease arises from one of many mutations in the gene encoding the cystic fibrosis transmembrane conductance regulator, or CFTR. The most common disease-associated allele, F508del, along with several other mutations affect the folding, transport, and stability of CFTR as it transits from the endoplasmic reticulum (ER) to the plasma membrane, where it functions primarily as a chloride channel. Early data demonstrated that F508del CFTR is selected for ER associated degradation (ERAD), a pathway in which misfolded proteins are recognized by ER-associated molecular chaperones, ubiquitinated, and delivered to the proteasome for degradation. Later studies showed that F508del CFTR that is rescued from ERAD and folds can alternatively be selected for enhanced endocytosis and lysosomal degradation. A number of other disease-causing mutations in CFTR also undergo these events. Fortunately, pharmacological modulators of CFTR biogenesis can repair CFTR, permitting its folding, escape from ERAD, and function at the cell surface. In this article, we review the many cellular checkpoints that monitor CFTR biogenesis, discuss the emergence of effective treatments for CF, and highlight future areas of research on the proteostatic control of CFTR.
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14
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Needham PG, Guerriero CJ, Brodsky JL. Chaperoning Endoplasmic Reticulum-Associated Degradation (ERAD) and Protein Conformational Diseases. Cold Spring Harb Perspect Biol 2019; 11:cshperspect.a033928. [PMID: 30670468 DOI: 10.1101/cshperspect.a033928] [Citation(s) in RCA: 85] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Misfolded proteins compromise cellular homeostasis. This is especially problematic in the endoplasmic reticulum (ER), which is a high-capacity protein-folding compartment and whose function requires stringent protein quality-control systems. Multiprotein complexes in the ER are able to identify, remove, ubiquitinate, and deliver misfolded proteins to the 26S proteasome for degradation in the cytosol, and these events are collectively termed ER-associated degradation, or ERAD. Several steps in the ERAD pathway are facilitated by molecular chaperone networks, and the importance of ERAD is highlighted by the fact that this pathway is linked to numerous protein conformational diseases. In this review, we discuss the factors that constitute the ERAD machinery and detail how each step in the pathway occurs. We then highlight the underlying pathophysiology of protein conformational diseases associated with ERAD.
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Affiliation(s)
- Patrick G Needham
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
| | | | - Jeffrey L Brodsky
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
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15
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Huang Y, Arora K, Mun KS, Yang F, Moon C, Yarlagadda S, Jegga A, Weaver T, Naren AP. Targeting DNAJB9, a novel ER luminal co-chaperone, to rescue ΔF508-CFTR. Sci Rep 2019; 9:9808. [PMID: 31285458 PMCID: PMC6614449 DOI: 10.1038/s41598-019-46161-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Accepted: 06/19/2019] [Indexed: 01/30/2023] Open
Abstract
The molecular mechanism of Endoplasmic Reticulum-associated degradation (ERAD) of Cystic fibrosis transmembrane-conductance regulator (CFTR) is largely unknown. Particularly, it is unknown what ER luminal factor(s) are involved in ERAD. Herein, we used ProtoArray to identify an ER luminal co-chaperone, DNAJB9, which can directly interact with CFTR. For both WT- and ΔF508 (deletion of phenylalanine at position 508, the most common CF-causing mutant)-CFTR, knockdown of DNAJB9 by siRNA increased their expression levels on the cell surface and, consequently, upregulated their function. Furthermore, genetic ablation of DNAJB9 in WT mice increased CFTR expression and enhanced CFTR-dependent fluid secretion in enteroids. Importantly, DNAJB9 deficiency upregulated enteroids' fluid secretion in CF mice (homozygous for ΔF508), and silencing one allele of DNAJB9 is sufficient to rescue ΔF508-CFTR in vitro and in vivo, suggesting that DNAJB9 may be a rate-limiting factor in CFTR ERAD pathway. Our studies identified the first ER luminal co-chaperone involved in CFTR ERAD, and DNAJB9 could be a novel therapeutic target for CF.
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Affiliation(s)
- Yunjie Huang
- Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, United States
| | - Kavisha Arora
- Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, United States
| | - Kyu Shik Mun
- Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, United States
| | - Fanmuyi Yang
- Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, United States
| | - ChangSuk Moon
- Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, United States
| | - Sunitha Yarlagadda
- Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, United States
| | - Anil Jegga
- Division of Biomedical Informatics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, United States
| | - Timothy Weaver
- Division of Pulmonary Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, United States
| | - Anjaparavanda P Naren
- Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, United States.
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16
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Donato M, Geisler M. HSP
90 and co‐chaperones: a multitaskers’ view on plant hormone biology. FEBS Lett 2019; 593:1415-1430. [DOI: 10.1002/1873-3468.13499] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 06/12/2019] [Accepted: 06/12/2019] [Indexed: 12/30/2022]
Affiliation(s)
- Martin Donato
- Department of Biology University of Fribourg Switzerland
| | - Markus Geisler
- Department of Biology University of Fribourg Switzerland
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17
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Xu SS, Xu LG, Yuan C, Li SN, Chen T, Wang W, Li C, Cao L, Rao H. FKBP8 inhibits virus-induced RLR-VISA signaling. J Med Virol 2019; 91:482-492. [PMID: 30267576 DOI: 10.1002/jmv.25327] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2018] [Accepted: 09/25/2018] [Indexed: 12/19/2022]
Abstract
The mitochondrial antiviral signal protein mitochondrial antiviral signaling protein, also known as virus-induced signaling adaptor (VISA), plays a key role in regulating host innate immune signaling pathways. This study identifies FK506 binding protein 8 (FKBP8) as a candidate interacting protein of VISA through the yeast two-hybrid technique. The interaction of FKBP8 with VISA, retinoic acid inducible protein 1 (RIG-I), and IFN regulatory factor 3 (IRF3) was confirmed during viral infection in mammalian cells by coimmunoprecipitation. Overexpression of FKBP8 using a eukaryotic expression plasmid significantly attenuated Sendai virus-induced activation of the promoter interferons β (IFN-β), and transcription factors nuclear factor κ-light chain enhancer of activated B cells (NF-κB) and IFN-stimulated response element (ISRE). Overexpression of FKBP8 also decreased dimer-IRF3 activity, but enhanced virus replication. Conversely, knockdown of FKBP8 expression by RNA interference showed opposite effects. Further studies indicated that FKBP8 acts as a negative interacting partner to regulate RLR-VISA signaling by acting on VISA and TANK binding kinase 1 (TBK1). Additionally, FKBP8 played a negative role on virus-induced signaling by inhibiting the formation of TBK1-IRF3 and VISA-TRAF3 complexes. Notably, FKBP8 also promoted the degradation of TBK1, RIG-I, and TRAF3 resulting from FKBP8 reinforced Sendai virus-induced endogenous polyubiquitination of RIG-I, TBK1, and TNF receptor-associated factor 3 (TRAF3). Therefore, a novel function of FKBP8 in innate immunity antiviral signaling regulation was revealed in this study.
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Affiliation(s)
- Shan-Shan Xu
- Key Laboratory of Functional Small Organic Molecules, Ministry of Education and College of Life Science, Jiangxi Normal University, Nanchang, China
| | - Liang-Guo Xu
- Key Laboratory of Functional Small Organic Molecules, Ministry of Education and College of Life Science, Jiangxi Normal University, Nanchang, China
| | - Cailei Yuan
- Jiangxi Key Laboratory of Nanomaterials and Sensors, School of Physics, Communication and Electronics, Jiangxi Normal University, Nanchang, China
| | - Sheng-Na Li
- Key Laboratory of Functional Small Organic Molecules, Ministry of Education and College of Life Science, Jiangxi Normal University, Nanchang, China
| | - Tian Chen
- Key Laboratory of Functional Small Organic Molecules, Ministry of Education and College of Life Science, Jiangxi Normal University, Nanchang, China
| | - Weiying Wang
- Key Laboratory of Functional Small Organic Molecules, Ministry of Education and College of Life Science, Jiangxi Normal University, Nanchang, China
| | - Changsheng Li
- Key Laboratory of Functional Small Organic Molecules, Ministry of Education and College of Life Science, Jiangxi Normal University, Nanchang, China
| | - Lingzhen Cao
- Key Laboratory of Functional Small Organic Molecules, Ministry of Education and College of Life Science, Jiangxi Normal University, Nanchang, China
| | - Hua Rao
- Key Laboratory of Functional Small Organic Molecules, Ministry of Education and College of Life Science, Jiangxi Normal University, Nanchang, China
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18
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FKBP8 Enhances Protein Stability of the CLC-1 Chloride Channel at the Plasma Membrane. Int J Mol Sci 2018; 19:ijms19123783. [PMID: 30487393 PMCID: PMC6320802 DOI: 10.3390/ijms19123783] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Revised: 11/18/2018] [Accepted: 11/26/2018] [Indexed: 01/23/2023] Open
Abstract
Mutations in the skeletal muscle-specific CLC-1 chloride channel are associated with the human hereditary disease myotonia congenita. The molecular pathophysiology underlying some of the disease-causing mutations can be ascribed to defective human CLC-1 protein biosynthesis. CLC-1 protein folding is assisted by several molecular chaperones and co-chaperones, including FK506-binding protein 8 (FKBP8). FKBP8 is generally considered an endoplasmic reticulum- and mitochondrion-resident membrane protein, but is not thought to contribute to protein quality control at the cell surface. Herein, we aim to test the hypothesis that FKBP8 may regulate CLC-1 protein at the plasma membrane. Surface biotinylation and subcellular fractionation analyses reveal that a portion of FKBP8 is present at the plasma membrane, and that co-expression with CLC-1 enhances surface localization of FKBP8. Immunoblotting analyses of plasma membrane proteins purified from skeletal muscle further confirm surface localization of FKBP8. Importantly, FKBP8 promotes CLC-1 protein stability at the plasma membrane. Together, our data underscore the importance of FKBP8 in the peripheral quality control of CLC-1 channel.
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19
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Hutt DM, Loguercio S, Campos AR, Balch WE. A Proteomic Variant Approach (ProVarA) for Personalized Medicine of Inherited and Somatic Disease. J Mol Biol 2018; 430:2951-2973. [PMID: 29924966 PMCID: PMC6097907 DOI: 10.1016/j.jmb.2018.06.017] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 06/07/2018] [Accepted: 06/08/2018] [Indexed: 12/21/2022]
Abstract
The advent of precision medicine for genetic diseases has been hampered by the large number of variants that cause familial and somatic disease, a complexity that is further confounded by the impact of genetic modifiers. To begin to understand differences in onset, progression and therapeutic response that exist among disease-causing variants, we present the proteomic variant approach (ProVarA), a proteomic method that integrates mass spectrometry with genomic tools to dissect the etiology of disease. To illustrate its value, we examined the impact of variation in cystic fibrosis (CF), where 2025 disease-associated mutations in the CF transmembrane conductance regulator (CFTR) gene have been annotated and where individual genotypes exhibit phenotypic heterogeneity and response to therapeutic intervention. A comparative analysis of variant-specific proteomics allows us to identify a number of protein interactions contributing to the basic defects associated with F508del- and G551D-CFTR, two of the most common disease-associated variants in the patient population. We demonstrate that a number of these causal interactions are significantly altered in response to treatment with Vx809 and Vx770, small-molecule therapeutics that respectively target the F508del and G551D variants. ProVarA represents the first comparative proteomic analysis among multiple disease-causing mutations, thereby providing a methodological approach that provides a significant advancement to existing proteomic efforts in understanding the impact of variation in CF disease. We posit that the implementation of ProVarA for any familial or somatic mutation will provide a substantial increase in the knowledge base needed to implement a precision medicine-based approach for clinical management of disease.
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Affiliation(s)
- Darren M Hutt
- The Scripps Research Institute, Department of Molecular Medicine, 10550 North Torrey Pines Rd, La Jolla CA USA 92037
| | - Salvatore Loguercio
- The Scripps Research Institute, Department of Molecular Medicine, 10550 North Torrey Pines Rd, La Jolla CA USA 92037
| | - Alexandre Rosa Campos
- Sanford Burnham Prebys Medical Discovery Institute Proteomic Core 10901 North Torrey Pines Road, La Jolla CA USA 92037
| | - William E Balch
- The Scripps Research Institute, Department of Molecular Medicine, 10550 North Torrey Pines Rd, La Jolla CA USA 92037
- Integrative Structural and Computational Biology, 10550 North Torrey Pines Rd, La Jolla CA USA 92037
- The Skaggs Institute for Chemical Biology, 10550 North Torrey Pines Rd, La Jolla CA USA 92037
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20
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Hutt DM, Loguercio S, Roth DM, Su AI, Balch WE. Correcting the F508del-CFTR variant by modulating eukaryotic translation initiation factor 3-mediated translation initiation. J Biol Chem 2018; 293:13477-13495. [PMID: 30006345 DOI: 10.1074/jbc.ra118.003192] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 07/05/2018] [Indexed: 12/31/2022] Open
Abstract
Inherited and somatic rare diseases result from >200,000 genetic variants leading to loss- or gain-of-toxic function, often caused by protein misfolding. Many of these misfolded variants fail to properly interact with other proteins. Understanding the link between factors mediating the transcription, translation, and protein folding of these disease-associated variants remains a major challenge in cell biology. Herein, we utilized the cystic fibrosis transmembrane conductance regulator (CFTR) protein as a model and performed a proteomics-based high-throughput screen (HTS) to identify pathways and components affecting the folding and function of the most common cystic fibrosis-associated mutation, the F508del variant of CFTR. Using a shortest-path algorithm we developed, we mapped HTS hits to the CFTR interactome to provide functional context to the targets and identified the eukaryotic translation initiation factor 3a (eIF3a) as a central hub for the biogenesis of CFTR. Of note, siRNA-mediated silencing of eIF3a reduced the polysome-to-monosome ratio in F508del-expressing cells, which, in turn, decreased the translation of CFTR variants, leading to increased CFTR stability, trafficking, and function at the cell surface. This finding suggested that eIF3a is involved in mediating the impact of genetic variations in CFTR on the folding of this protein. We posit that the number of ribosomes on a CFTR mRNA transcript is inversely correlated with the stability of the translated polypeptide. Polysome-based translation challenges the capacity of the proteostasis environment to balance message fidelity with protein folding, leading to disease. We suggest that this deficit can be corrected through control of translation initiation.
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Affiliation(s)
| | | | | | - Andrew I Su
- Integrative Structural and Computational Biology and
| | - William E Balch
- From the Departments of Molecular Medicine and .,the Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California 92037
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21
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Mali GR, Yeyati PL, Mizuno S, Dodd DO, Tennant PA, Keighren MA, Zur Lage P, Shoemark A, Garcia-Munoz A, Shimada A, Takeda H, Edlich F, Takahashi S, von Kreigsheim A, Jarman AP, Mill P. ZMYND10 functions in a chaperone relay during axonemal dynein assembly. eLife 2018; 7:34389. [PMID: 29916806 PMCID: PMC6044906 DOI: 10.7554/elife.34389] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 06/18/2018] [Indexed: 11/13/2022] Open
Abstract
Molecular chaperones promote the folding and macromolecular assembly of a diverse set of 'client' proteins. How ubiquitous chaperone machineries direct their activities towards specific sets of substrates is unclear. Through the use of mouse genetics, imaging and quantitative proteomics we uncover that ZMYND10 is a novel co-chaperone that confers specificity for the FKBP8-HSP90 chaperone complex towards axonemal dynein clients required for cilia motility. Loss of ZMYND10 perturbs the chaperoning of axonemal dynein heavy chains, triggering broader degradation of dynein motor subunits. We show that pharmacological inhibition of FKBP8 phenocopies dynein motor instability associated with the loss of ZMYND10 in airway cells and that human disease-causing variants of ZMYND10 disrupt its ability to act as an FKBP8-HSP90 co-chaperone. Our study indicates that primary ciliary dyskinesia (PCD), caused by mutations in dynein assembly factors disrupting cytoplasmic pre-assembly of axonemal dynein motors, should be considered a cell-type specific protein-misfolding disease.
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Affiliation(s)
- Girish R Mali
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | - Patricia L Yeyati
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | - Seiya Mizuno
- Laboratory Animal Resource Centre, University of Tsukuba, Tsukuba, Japan
| | - Daniel O Dodd
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | - Peter A Tennant
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | - Margaret A Keighren
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | - Petra Zur Lage
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Amelia Shoemark
- Division of Molecular and Clinical Medicine, University of Dundee, Dundee, United Kingdom
| | | | - Atsuko Shimada
- Department of Biological Sciences, University of Tokyo, Tokyo, Japan
| | - Hiroyuki Takeda
- Department of Biological Sciences, University of Tokyo, Tokyo, Japan
| | - Frank Edlich
- Institute for Biochemistry and Molecular Biology, University of Freiburg, Freiburg, Germany.,BIOSS, Centre for Biological Signaling Studies, University of Freiburg, Freiburg, Germany
| | - Satoru Takahashi
- Laboratory Animal Resource Centre, University of Tsukuba, Tsukuba, Japan.,Department of Anatomy and Embryology, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
| | - Alex von Kreigsheim
- Systems Biology Ireland, University College Dublin, Dublin, Ireland.,Edinburgh Cancer Research UK Centre, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | - Andrew P Jarman
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Pleasantine Mill
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
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22
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Strategies for the etiological therapy of cystic fibrosis. Cell Death Differ 2017; 24:1825-1844. [PMID: 28937684 PMCID: PMC5635223 DOI: 10.1038/cdd.2017.126] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Revised: 06/22/2017] [Accepted: 06/23/2017] [Indexed: 12/14/2022] Open
Abstract
Etiological therapies aim at repairing the underlying cause of cystic fibrosis (CF), which is the functional defect of the cystic fibrosis transmembrane conductance regulator (CFTR) protein owing to mutations in the CFTR gene. Among these, the F508del CFTR mutation accounts for more than two thirds of CF cases worldwide. Two somehow antinomic schools of thought conceive CFTR repair in a different manner. According to one vision, drugs should directly target the mutated CFTR protein to increase its plasma membrane expression (correctors) or improve its ion transport function (potentiators). An alternative strategy consists in modulating the cellular environment and proteostasis networks in which the mutated CFTR protein is synthesized, traffics to its final destination, the plasma membrane, and is turned over. We will analyze distinctive advantages and drawbacks of these strategies in terms of their scientific and clinical dimensions, and we will propose a global strategy for CF research and development based on a reconciliatory approach. Moreover, we will discuss the utility of preclinical biomarkers that may guide the personalized, patient-specific implementation of CF therapies.
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23
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O'Donnell BM, Mackie TD, Subramanya AR, Brodsky JL. Endoplasmic reticulum-associated degradation of the renal potassium channel, ROMK, leads to type II Bartter syndrome. J Biol Chem 2017. [PMID: 28630040 DOI: 10.1074/jbc.m117.786376] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Type II Bartter syndrome is caused by mutations in the renal outer medullary potassium (ROMK) channel, but the molecular mechanisms underlying this disease are poorly defined. To rapidly screen for ROMK function, we developed a yeast expression system and discovered that yeast cells lacking endogenous potassium channels could be rescued by WT ROMK but not by ROMK proteins containing any one of four Bartter mutations. We also found that the mutant proteins were significantly less stable than WT ROMK. However, their degradation was slowed in the presence of a proteasome inhibitor or when yeast cells contained mutations in the CDC48 or SSA1 gene, which is required for endoplasmic reticulum (ER)-associated degradation (ERAD). Consistent with these data, sucrose gradient centrifugation and indirect immunofluorescence microscopy indicated that most ROMK protein was ER-localized. To translate these findings to a more relevant cell type, we measured the stabilities of WT ROMK and the ROMK Bartter mutants in HEK293 cells. As in yeast, the Bartter mutant proteins were less stable than the WT protein, and their degradation was slowed in the presence of a proteasome inhibitor. Finally, we discovered that low-temperature incubation increased the steady-state levels of a Bartter mutant, suggesting that the disease-causing mutation traps the protein in a folding-deficient conformation. These findings indicate that the underlying pathology for at least a subset of patients with type II Bartter syndrome is linked to the ERAD pathway and that future therapeutic strategies should focus on correcting deficiencies in ROMK folding.
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Affiliation(s)
- Brighid M O'Donnell
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania 15260; Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15261
| | - Timothy D Mackie
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
| | - Arohan R Subramanya
- Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15261
| | - Jeffrey L Brodsky
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania 15260.
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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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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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26
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Learning from each other: ABC transporter regulation by protein phosphorylation in plant and mammalian systems. Biochem Soc Trans 2016; 43:966-74. [PMID: 26517911 DOI: 10.1042/bst20150128] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The ABC (ATP-binding cassette) transporter family in higher plants is highly expanded compared with those of mammalians. Moreover, some members of the plant ABC subfamily B (ABCB) display very high substrate specificity compared with their mammalian counterparts that are often associated with multi-drug resistance phenomena. In this review, we highlight prominent functions of plant and mammalian ABC transporters and summarize our knowledge on their post-transcriptional regulation with a focus on protein phosphorylation. A deeper comparison of regulatory events of human cystic fibrosis transmembrane conductance regulator (CFTR) and ABCB1 from the model plant Arabidopsis reveals a surprisingly high degree of similarity. Both physically interact with orthologues of the FK506-binding proteins that chaperon both transporters to the plasma membrane in an action that seems to involve heat shock protein (Hsp)90. Further, both transporters are phosphorylated at regulatory domains that connect both nt-binding folds. Taken together, it appears that ABC transporters exhibit an evolutionary conserved but complex regulation by protein phosphorylation, which apparently is, at least in some cases, tightly connected with protein-protein interactions (PPI).
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27
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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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28
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Correction: Learning from each other: ABC transporter regulation by protein phosphorylation in plant and mammalian systems. Biochem Soc Trans 2016; 44:663-73. [DOI: 10.1042/bst20150128_2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Indexed: 12/31/2022]
Abstract
The ABC (ATP-binding cassette) transporter family in higher plants is highly expanded compared with those of mammalians. Moreover, some members of the plant ABCB subfamily display very high substrate specificity compared with their mammalian counterparts that are often associated with multidrug resistance (MDR) phenomena. In this review we highlight prominent functions of plant and mammalian ABC transporters and summarize our knowledge on their post-transcriptional regulation with a focus on protein phosphorylation. A deeper comparison of regulatory events of human cystic fibrosis transmembrane conductance regulator (CFTR) and ABCB1 from the model plant Arabidopsis reveals a surprisingly high degree of similarity. Both physically interact with orthologues of the FK506-binding proteins (FKBPs) that chaperon both transporters to the plasma membrane in an action that seems to involve Hsp90. Further both transporters are phosphorylated at regulatory domains that connect both nucleotide-binding folds. Taken together it appears that ABC transporters exhibit an evolutionary conserved but complex regulation by protein phosphorylation, which apparently is, at least in some cases, tightly connected with protein–protein interactions (PPI).
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29
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A novel Hsp70 inhibitor prevents cell intoxication with the actin ADP-ribosylating Clostridium perfringens iota toxin. Sci Rep 2016; 6:20301. [PMID: 26839186 PMCID: PMC4738285 DOI: 10.1038/srep20301] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 12/30/2015] [Indexed: 12/14/2022] Open
Abstract
Hsp70 family proteins are folding helper proteins involved in a wide variety of cellular pathways. Members of this family interact with key factors in signal transduction, transcription, cell-cycle control, and stress response. Here, we developed the first Hsp70 low molecular weight inhibitor specifically targeting the peptide binding site of human Hsp70. After demonstrating that the inhibitor modulates the Hsp70 function in the cell, we used the inhibitor to show for the first time that the stress-inducible chaperone Hsp70 functions as molecular component for entry of a bacterial protein toxin into mammalian cells. Pharmacological inhibition of Hsp70 protected cells from intoxication with the binary actin ADP-ribosylating iota toxin from Clostridium perfringens, the prototype of a family of enterotoxins from pathogenic Clostridia and inhibited translocation of its enzyme component across cell membranes into the cytosol. This finding offers a starting point for novel therapeutic strategies against certain bacterial toxins.
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30
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Amaral MD, Balch WE. Hallmarks of therapeutic management of the cystic fibrosis functional landscape. J Cyst Fibros 2015; 14:687-99. [PMID: 26526359 PMCID: PMC4644672 DOI: 10.1016/j.jcf.2015.09.006] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Revised: 09/16/2015] [Accepted: 09/16/2015] [Indexed: 01/29/2023]
Abstract
The cystic fibrosis (CF) transmembrane conductance regulator (CFTR) protein does not operate in isolation, rather in a dynamic network of interacting components that impact its synthesis, folding, stability, intracellular location and function, referred to herein as the 'CFTR Functional Landscape (CFFL)'. For the prominent F508del mutation, many of these interactors are deeply connected to a protein fold management system, the proteostasis network (PN). However, CF encompasses an additional 2000 CFTR variants distributed along its entire coding sequence (referred to as CFTR2), and each variant contributes a differential liability to PN management of CFTR and to a protein 'social network' (SN) that directs the probability of the (patho)physiologic events that impact ion transport in each cell, tissue and patient in health and disease. Recognition of the importance of the PN and SN in driving the unique patient CFFL leading to disease highlights the importance of precision medicine in therapeutic management of disease progression. We take the view herein that it is not CFTR, rather the PN/SN, and their impact on the CFFL, that are the key physiologic forces driving onset and clinical progression of CF. We posit that a deep understanding of each patients PN/SN gained by merging genomic, proteomic (mass spectrometry (MS)), and high-content microscopy (HCM) technologies in the context of novel network learning algorithms will lead to a paradigm shift in CF clinical management. This should allow for generation of new classes of patient specific PN/SN directed therapeutics for personalized management of the CFFL in the clinic.
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Affiliation(s)
- Margarida D Amaral
- University of Lisboa, Faculty of Sciences, BioISI - Biosystems & Integrative Sciences Institute, Lisboa, Portugal.
| | - William E Balch
- Department of Chemical Physiology, Department of Cell and Molecular Biology, The Skaggs Institute of Chemical Biology, The Scripps Research Institute, La Jolla, CA, USA.
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31
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Buck TM, Jordan R, Lyons-Weiler J, Adelman JL, Needham PG, Kleyman TR, Brodsky JL. Expression of three topologically distinct membrane proteins elicits unique stress response pathways in the yeast Saccharomyces cerevisiae. Physiol Genomics 2015; 47:198-214. [PMID: 25759377 DOI: 10.1152/physiolgenomics.00101.2014] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Accepted: 03/04/2015] [Indexed: 01/11/2023] Open
Abstract
Misfolded membrane proteins are retained in the endoplasmic reticulum (ER) and are subject to ER-associated degradation, which clears the secretory pathway of potentially toxic species. While the transcriptional response to environmental stressors has been extensively studied, limited data exist describing the cellular response to misfolded membrane proteins. To this end, we expressed and then compared the transcriptional profiles elicited by the synthesis of three ER retained, misfolded ion channels: The α-subunit of the epithelial sodium channel, ENaC, the cystic fibrosis transmembrane conductance regulator, CFTR, and an inwardly rectifying potassium channel, Kir2.1, which vary in their mass, membrane topologies, and quaternary structures. To examine transcriptional profiles in a null background, the proteins were expressed in yeast, which was previously used to examine the degradation requirements for each substrate. Surprisingly, the proteins failed to induce a canonical unfolded protein response or heat shock response, although messages encoding several cytosolic and ER lumenal protein folding factors rose when αENaC or CFTR was expressed. In contrast, the levels of these genes were unaltered by Kir2.1 expression; instead, the yeast iron regulon was activated. Nevertheless, a significant number of genes that respond to various environmental stressors were upregulated by all three substrates, and compared with previous microarray data we deduced the existence of a group of genes that reflect a novel misfolded membrane protein response. These data indicate that aberrant proteins in the ER elicit profound yet unique cellular responses.
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Affiliation(s)
- Teresa M Buck
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Rick Jordan
- GPCL Bioinformatics Analysis Core, University of Pittsburgh, Pittsburgh, Pennsylvania; and
| | - James Lyons-Weiler
- GPCL Bioinformatics Analysis Core, University of Pittsburgh, Pittsburgh, Pennsylvania; and
| | - Joshua L Adelman
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Patrick G Needham
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Thomas R Kleyman
- Department of Medicine, Renal-Electrolyte Division, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Jeffrey L Brodsky
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania;
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32
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Roth DM, Hutt DM, Tong J, Bouchecareilh M, Wang N, Seeley T, Dekkers JF, Beekman JM, Garza D, Drew L, Masliah E, Morimoto RI, Balch WE. Modulation of the maladaptive stress response to manage diseases of protein folding. PLoS Biol 2014; 12:e1001998. [PMID: 25406061 PMCID: PMC4236052 DOI: 10.1371/journal.pbio.1001998] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Accepted: 10/07/2014] [Indexed: 12/31/2022] Open
Abstract
Diseases of protein folding arise because of the inability of an altered peptide sequence to properly engage protein homeostasis components that direct protein folding and function. To identify global principles of misfolding disease pathology we examined the impact of the local folding environment in alpha-1-antitrypsin deficiency (AATD), Niemann-Pick type C1 disease (NPC1), Alzheimer's disease (AD), and cystic fibrosis (CF). Using distinct models, including patient-derived cell lines and primary epithelium, mouse brain tissue, and Caenorhabditis elegans, we found that chronic expression of misfolded proteins not only triggers the sustained activation of the heat shock response (HSR) pathway, but that this sustained activation is maladaptive. In diseased cells, maladaptation alters protein structure-function relationships, impacts protein folding in the cytosol, and further exacerbates the disease state. We show that down-regulation of this maladaptive stress response (MSR), through silencing of HSF1, the master regulator of the HSR, restores cellular protein folding and improves the disease phenotype. We propose that restoration of a more physiological proteostatic environment will strongly impact the management and progression of loss-of-function and gain-of-toxic-function phenotypes common in human disease.
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Affiliation(s)
- Daniela Martino Roth
- Department of Cell Biology, The Scripps Research Institute, La Jolla, California, United States of America
| | - Darren M. Hutt
- Department of Cell Biology, The Scripps Research Institute, La Jolla, California, United States of America
| | - Jiansong Tong
- Department of Cell Biology, The Scripps Research Institute, La Jolla, California, United States of America
| | - Marion Bouchecareilh
- Department of Cell Biology, The Scripps Research Institute, La Jolla, California, United States of America
| | - Ning Wang
- Department of Molecular Biosciences, Rice Institute for Biomedical Research, Northwestern University, Evanston, Illinois, United States of America
| | - Theo Seeley
- Department of Cell Biology, The Scripps Research Institute, La Jolla, California, United States of America
| | - Johanna F. Dekkers
- Department of Pediatric Pulmonology, Wilhelmina Children's Hospital, University Medical Centre, Utrecht, The Netherlands
- Laboratory of Translational Immunology, Wilhelmina Children's Hospital, University Medical Centre, Utrecht, The Netherlands
| | - Jeffrey M. Beekman
- Department of Pediatric Pulmonology, Wilhelmina Children's Hospital, University Medical Centre, Utrecht, The Netherlands
- Laboratory of Translational Immunology, Wilhelmina Children's Hospital, University Medical Centre, Utrecht, The Netherlands
| | - Dan Garza
- Proteostasis Therapeutics Inc., Cambridge, Massachusetts, United States of America
| | - Lawrence Drew
- Proteostasis Therapeutics Inc., Cambridge, Massachusetts, United States of America
| | - Eliezer Masliah
- Department of Neurosciences, University of California, San Diego, La Jolla, California, United States of America
| | - Richard I. Morimoto
- Department of Molecular Biosciences, Rice Institute for Biomedical Research, Northwestern University, Evanston, Illinois, United States of America
| | - William E. Balch
- Department of Cell Biology, The Scripps Research Institute, La Jolla, California, United States of America
- The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California, United States of America
- Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California, United States of America
- The Institute for Childhood and Neglected Diseases, The Scripps Research Institute, La Jolla, California, United States of America
- * E-mail:
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33
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Hutt DM, Balch WE. Expanding proteostasis by membrane trafficking networks. Cold Spring Harb Perspect Biol 2013; 5:cshperspect.a013383. [PMID: 23426524 DOI: 10.1101/cshperspect.a013383] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The folding biology common to all three kingdoms of life (Archaea, Bacteria, and Eukarya) is proteostasis. The proteostasis network (PN) functions as a "cloud" to generate, protect, and degrade the proteome. Whereas microbes (Bacteria, Archaea) have a single compartment, Eukarya have numerous subcellular compartments. We examine evidence that Eukarya compartments use coat, tether, and fusion (CTF) membrane trafficking components to form an evolutionarily advanced arm of the PN that we refer to as the "trafficking PN" (TPN). We suggest that the TPN builds compartments by generating a mosaic of integrated cargo-specific trafficking signatures (TRaCKS). TRaCKS control the temporal and spatial features of protein-folding biology based on the Anfinsen principle that the local environment plays a critical role in managing protein structure. TPN-generated endomembrane compartments apply a "quinary" level of structural control to modify the secondary, tertiary, and quaternary structures defined by the primary polypeptide-chain sequence. The development of Anfinsen compartments provides a unifying foundation for understanding the purpose of endomembrane biology and its capacity to drive extant Eukarya function and diversity.
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Affiliation(s)
- Darren M Hutt
- Department of Cell Biology and Department of Chemical Physiology, The Skaggs Institute for Chemical Biology and the Dorris Institute for Neurological Diseases, The Scripps Research Institute, La Jolla, California 92037, USA
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Buck TM, Plavchak L, Roy A, Donnelly BF, Kashlan OB, Kleyman TR, Subramanya AR, Brodsky JL. The Lhs1/GRP170 chaperones facilitate the endoplasmic reticulum-associated degradation of the epithelial sodium channel. J Biol Chem 2013; 288:18366-80. [PMID: 23645669 DOI: 10.1074/jbc.m113.469882] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The epithelial sodium channel, ENaC, plays a critical role in maintaining salt and water homeostasis, and not surprisingly defects in ENaC function are associated with disease. Like many other membrane-spanning proteins, this trimeric protein complex folds and assembles inefficiently in the endoplasmic reticulum (ER), which results in a substantial percentage of the channel being targeted for ER-associated degradation (ERAD). Because the spectrum of factors that facilitates the degradation of ENaC is incomplete, we developed yeast expression systems for each ENaC subunit. We discovered that a conserved Hsp70-like chaperone, Lhs1, is required for maximal turnover of the ENaC α subunit. By expressing Lhs1 ATP binding mutants, we also found that the nucleotide exchange properties of this chaperone are dispensable for ENaC degradation. Consistent with the precipitation of an Lhs1-αENaC complex, Lhs1 holdase activity was instead most likely required to support the ERAD of αENaC. Moreover, a complex containing the mammalian Lhs1 homolog GRP170 and αENaC co-precipitated, and GRP170 also facilitated ENaC degradation in human, HEK293 cells, and in a Xenopus oocyte expression system. In both yeast and higher cell types, the effect of Lhs1 on the ERAD of αENaC was selective for the unglycosylated form of the protein. These data establish the first evidence that Lhs1/Grp170 chaperones can act as mediators of ERAD substrate selection.
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Affiliation(s)
- Teresa M Buck
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
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35
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Kim SJ, Skach WR. Mechanisms of CFTR Folding at the Endoplasmic Reticulum. Front Pharmacol 2012; 3:201. [PMID: 23248597 PMCID: PMC3521238 DOI: 10.3389/fphar.2012.00201] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2012] [Accepted: 11/23/2012] [Indexed: 12/20/2022] Open
Abstract
In the past decade much has been learned about how Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) folds and misfolds as the etiologic cause of cystic fibrosis (CF). CFTR folding is complex and hierarchical, takes place in multiple cellular compartments and physical environments, and involves several large networks of folding machineries. Insertion of transmembrane (TM) segments into the endoplasmic reticulum (ER) membrane and tertiary folding of cytosolic domains begin cotranslationally as the nascent polypeptide emerges from the ribosome, whereas posttranslational folding establishes critical domain-domain contacts needed to form a physiologically stable structure. Within the membrane, N- and C-terminal TM helices are sorted into bundles that project from the cytosol to form docking sites for nucleotide binding domains, NBD1 and NBD2, which in turn form a sandwich dimer for ATP binding. While tertiary folding is required for domain assembly, proper domain assembly also reciprocally affects folding of individual domains analogous to a jig-saw puzzle wherein the structure of each interlocking piece influences its neighbors. Superimposed on this process is an elaborate proteostatic network of cellular chaperones and folding machineries that facilitate the timing and coordination of specific folding steps in and across the ER membrane. While the details of this process require further refinement, we finally have a useful framework to understand key folding defect(s) caused by ΔF508 that provides a molecular target(s) for the next generation of CFTR small molecule correctors aimed at the specific defect present in the majority of CF patients.
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Affiliation(s)
- Soo Jung Kim
- Department of Biochemistry and Molecular Biology, Oregon Health and Science University Portland, OR, USA
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