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van der Sluijs P, Hoelen H, Schmidt A, Braakman I. The Folding Pathway of ABC Transporter CFTR: Effective and Robust. J Mol Biol 2024; 436:168591. [PMID: 38677493 DOI: 10.1016/j.jmb.2024.168591] [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] [Received: 02/23/2024] [Revised: 04/16/2024] [Accepted: 04/23/2024] [Indexed: 04/29/2024]
Abstract
De novo protein folding into a native three-dimensional structure is indispensable for biological function, is instructed by its amino acid sequence, and occurs along a vectorial trajectory. The human proteome contains thousands of membrane-spanning proteins, whose biosynthesis begins on endoplasmic reticulum-associated ribosomes. Nearly half of all membrane proteins traverse the membrane more than once, including therapeutically important protein families such as solute carriers, G-protein-coupled receptors, and ABC transporters. These mediate a variety of functions like signal transduction and solute transport and are often of vital importance for cell function and tissue homeostasis. Missense mutations in multispan membrane proteins can lead to misfolding and cause disease; an example is the ABC transporter Cystic Fibrosis Transmembrane Conductance Regulator (CFTR). Even though our understanding of multispan membrane-protein folding still is rather rudimental, the cumulative knowledge of 20 years of basic research on CFTR folding has led to development of drugs that modulate the misfolded protein. This has provided the prospect of a life without CF to the vast majority of patients. In this review we describe our understanding of the folding pathway of CFTR in cells, which is modular and tolerates many defects, making it effective and robust. We address how modulator drugs affect folding and function of CFTR, and distinguish protein stability from its folding process. Since the domain architecture of (mammalian) ABC transporters are highly conserved, we anticipate that the insights we discuss here for folding of CFTR may lay the groundwork for understanding the general rules of ABC-transporter folding.
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Affiliation(s)
- Peter van der Sluijs
- Cellular Protein Chemistry, Bijvoet Centre for Biomolecular Research, Utrecht University, 3584 CH Utrecht, the Netherlands.
| | - Hanneke Hoelen
- Cellular Protein Chemistry, Bijvoet Centre for Biomolecular Research, Utrecht University, 3584 CH Utrecht, the Netherlands; Present address: GenDx, Yalelaan 48, 3584 CM Utrecht, The Netherlands
| | - Andre Schmidt
- Cellular Protein Chemistry, Bijvoet Centre for Biomolecular Research, Utrecht University, 3584 CH Utrecht, the Netherlands; 3D-Pharmxchange, Tilburg, the Netherlands
| | - Ineke Braakman
- Cellular Protein Chemistry, Bijvoet Centre for Biomolecular Research, Utrecht University, 3584 CH Utrecht, the Netherlands
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2
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Kleizen B, de Mattos E, Papaioannou O, Monti M, Tartaglia GG, van der Sluijs P, Braakman I. Transmembrane Helices 7 and 8 Confer Aggregation Sensitivity to the Cystic Fibrosis Transmembrane Conductance Regulator. Int J Mol Sci 2023; 24:15741. [PMID: 37958724 PMCID: PMC10648718 DOI: 10.3390/ijms242115741] [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: 09/04/2023] [Revised: 10/18/2023] [Accepted: 10/19/2023] [Indexed: 11/15/2023] Open
Abstract
The Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) is a large multi-spanning membrane protein that is susceptible to misfolding and aggregation. We have identified here the region responsible for this instability. Temperature-induced aggregation of C-terminally truncated versions of CFTR demonstrated that all truncations up to the second transmembrane domain (TMD2), including the R region, largely resisted aggregation. Limited proteolysis identified a folded structure that was prone to aggregation and consisted of TMD2 and at least part of the Regulatory Region R. Only when both TM7 (TransMembrane helix 7) and TM8 were present, TMD2 fragments became as aggregation-sensitive as wild-type CFTR, in line with increased thermo-instability of late CFTR nascent chains and in silico prediction of aggregation propensity. In accord, isolated TMD2 was degraded faster in cells than isolated TMD1. We conclude that TMD2 extended at its N-terminus with part of the R region forms a protease-resistant structure that induces heat instability in CFTR and may be responsible for its limited intracellular stability.
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Affiliation(s)
- Bertrand Kleizen
- Cellular Protein Chemistry, Bijvoet Centre for Biomolecular Research, Utrecht University, 3584 CH Utrecht, The Netherlands; (B.K.); (E.d.M.); (O.P.); (P.v.d.S.)
| | - Eduardo de Mattos
- Cellular Protein Chemistry, Bijvoet Centre for Biomolecular Research, Utrecht University, 3584 CH Utrecht, The Netherlands; (B.K.); (E.d.M.); (O.P.); (P.v.d.S.)
| | - Olga Papaioannou
- Cellular Protein Chemistry, Bijvoet Centre for Biomolecular Research, Utrecht University, 3584 CH Utrecht, The Netherlands; (B.K.); (E.d.M.); (O.P.); (P.v.d.S.)
| | - Michele Monti
- Center for Life Nano- & Neuro-Science, Fondazione Istituto Italiano di Tecnologia (IIT), 00161 Rome, Italy; (M.M.); (G.G.T.)
- Centre for Human Technologies (CHT), Istituto Italiano di Tecnologia (IIT), 16152 Genoa, Italy
| | - Gian Gaetano Tartaglia
- Center for Life Nano- & Neuro-Science, Fondazione Istituto Italiano di Tecnologia (IIT), 00161 Rome, Italy; (M.M.); (G.G.T.)
- Centre for Human Technologies (CHT), Istituto Italiano di Tecnologia (IIT), 16152 Genoa, Italy
| | - Peter van der Sluijs
- Cellular Protein Chemistry, Bijvoet Centre for Biomolecular Research, Utrecht University, 3584 CH Utrecht, The Netherlands; (B.K.); (E.d.M.); (O.P.); (P.v.d.S.)
| | - Ineke Braakman
- Cellular Protein Chemistry, Bijvoet Centre for Biomolecular Research, Utrecht University, 3584 CH Utrecht, The Netherlands; (B.K.); (E.d.M.); (O.P.); (P.v.d.S.)
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3
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Im J, Hillenaar T, Yeoh HY, Sahasrabudhe P, Mijnders M, van Willigen M, Hagos A, de Mattos E, van der Sluijs P, Braakman I. ABC-transporter CFTR folds with high fidelity through a modular, stepwise pathway. Cell Mol Life Sci 2023; 80:33. [PMID: 36609925 PMCID: PMC9825563 DOI: 10.1007/s00018-022-04671-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 11/01/2022] [Accepted: 11/28/2022] [Indexed: 01/09/2023]
Abstract
The question how proteins fold is especially pointed for large multi-domain, multi-spanning membrane proteins with complex topologies. We have uncovered the sequence of events that encompass proper folding of the ABC transporter CFTR in live cells by combining kinetic radiolabeling with protease-susceptibility assays. We found that CFTR folds in two clearly distinct stages. The first, co-translational, stage involves folding of the 2 transmembrane domains TMD1 and TMD2, plus one nucleotide-binding domain, NBD1. The second stage is a simultaneous, post-translational increase in protease resistance for both TMDs and NBD2, caused by assembly of these domains onto NBD1. Our assays probe every 2-3 residues (on average) in CFTR. This in-depth analysis at amino-acid level allows detailed analysis of domain folding and importantly also the next level: assembly of the domains into native, folded CFTR. Defects and changes brought about by medicines, chaperones, or mutations also are amenable to analysis. We here show that the well-known disease-causing mutation F508del, which established cystic fibrosis as protein-folding disease, caused co-translational misfolding of NBD1 but not TMD1 nor TMD2 in stage 1, leading to absence of stage-2 folding. Corrector drugs rescued stage 2 without rescuing NBD1. Likewise, the DxD motif in NBD1 that was identified to be required for export of CFTR from the ER we found to be required already upstream of export as CFTR mutated in this motif phenocopies F508del CFTR. The highly modular and stepwise folding process of such a large, complex protein explains the relatively high fidelity and correctability of its folding.
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Affiliation(s)
- Jisu Im
- Cellular Protein Chemistry, Faculty of Science, Bijvoet Centre for Biomolecular Research, Science for Life, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Tamara Hillenaar
- Cellular Protein Chemistry, Faculty of Science, Bijvoet Centre for Biomolecular Research, Science for Life, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Hui Ying Yeoh
- Cellular Protein Chemistry, Faculty of Science, Bijvoet Centre for Biomolecular Research, Science for Life, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands ,Present Address: Center of Translational Immunology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Priyanka Sahasrabudhe
- Cellular Protein Chemistry, Faculty of Science, Bijvoet Centre for Biomolecular Research, Science for Life, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands ,Present Address: Navigo Proteins GmbH, 06120 Halle, Germany
| | - Marjolein Mijnders
- Cellular Protein Chemistry, Faculty of Science, Bijvoet Centre for Biomolecular Research, Science for Life, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands ,Present Address: Princess Máxima Center for Pediatric Oncology, 3584 CS Utrecht, The Netherlands
| | - Marcel van Willigen
- Cellular Protein Chemistry, Faculty of Science, Bijvoet Centre for Biomolecular Research, Science for Life, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands ,Present Address: Julius Clinical Ltd, 3703 CD Zeist, The Netherlands
| | - Azib Hagos
- Cellular Protein Chemistry, Faculty of Science, Bijvoet Centre for Biomolecular Research, Science for Life, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Eduardo de Mattos
- Cellular Protein Chemistry, Faculty of Science, Bijvoet Centre for Biomolecular Research, Science for Life, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Peter van der Sluijs
- Cellular Protein Chemistry, Faculty of Science, Bijvoet Centre for Biomolecular Research, Science for Life, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Ineke Braakman
- Cellular Protein Chemistry, Faculty of Science, Bijvoet Centre for Biomolecular Research, Science for Life, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
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Anglès F, Wang C, Balch WE. Spatial covariance analysis reveals the residue-by-residue thermodynamic contribution of variation to the CFTR fold. Commun Biol 2022; 5:356. [PMID: 35418593 PMCID: PMC9008016 DOI: 10.1038/s42003-022-03302-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 03/21/2022] [Indexed: 12/21/2022] Open
Abstract
Although the impact of genome variation on the thermodynamic properties of function on the protein fold has been studied in vitro, it remains a challenge to assign these relationships across the entire polypeptide sequence in vivo. Using the Gaussian process regression based principle of Spatial CoVariance, we globally assign on a residue-by-residue basis the biological thermodynamic properties that contribute to the functional fold of CFTR in the cell. We demonstrate the existence of a thermodynamically sensitive region of the CFTR fold involving the interface between NBD1 and ICL4 that contributes to its export from endoplasmic reticulum. At the cell surface a new set of residues contribute uniquely to the management of channel function. These results support a general ‘quality assurance’ view of global protein fold management as an SCV principle describing the differential pre- and post-ER residue interactions contributing to compartmentalization of the energetics of the protein fold for function. Our results set the stage for future analyses of the quality systems managing protein sequence-to-function-to-structure broadly encompassing genome design leading to protein function in complex cellular relationships responsible for diversity and fitness in biology in response to the environment. Spatial covariance analysis shows how each residue in the critical fold region of chloride channel CFTR, defective in cystic fibrosis patients, contributes to CFTR’s export from the endoplasmic reticulum and function in the cell.
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Affiliation(s)
- Frédéric Anglès
- Scripps Research, Department of Molecular Medicine, 10550 North Torrey Pines Rd, La Jolla, CA, 92037, USA
| | - Chao Wang
- Scripps Research, Department of Molecular Medicine, 10550 North Torrey Pines Rd, La Jolla, CA, 92037, USA
| | - William E Balch
- Scripps Research, Department of Molecular Medicine, 10550 North Torrey Pines Rd, La Jolla, CA, 92037, USA.
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5
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Bahia MS, Khazanov N, Zhou Q, Yang Z, Wang C, Hong JS, Rab A, Sorscher EJ, Brouillette CG, Hunt JF, Senderowitz H. Stability Prediction for Mutations in the Cytosolic Domains of Cystic Fibrosis Transmembrane Conductance Regulator. J Chem Inf Model 2021; 61:1762-1777. [PMID: 33720715 DOI: 10.1021/acs.jcim.0c01207] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cystic Fibrosis (CF) is caused by mutations to the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) chloride channel. CFTR is composed of two membrane spanning domains, two cytosolic nucleotide-binding domains (NBD1 and NBD2) and a largely unstructured R-domain. Multiple CF-causing mutations reside in the NBDs and some are known to compromise the stability of these domains. The ability to predict the effect of mutations on the stability of the cytosolic domains of CFTR and to shed light on the mechanisms by which they exert their effect is therefore important in CF research. With this in mind, we have predicted the effect on domain stability of 59 mutations in NBD1 and NBD2 using 15 different algorithms and evaluated their performances via comparison to experimental data using several metrics including the correct classification rate (CCR), and the squared Pearson correlation (R2) and Spearman's correlation (ρ) calculated between the experimental ΔTm values and the computationally predicted ΔΔG values. Overall, the best results were obtained with FoldX and Rosetta. For NBD1 (35 mutations), FoldX provided R2 and ρ values of 0.64 and -0.71, respectively, with an 86% correct classification rate (CCR). For NBD2 (24 mutations), FoldX R2, ρ, and CCR were 0.51, -0.73, and 75%, respectively. Application of the Rosetta high-resolution protocol (Rosetta_hrp) to NBD1 yielded R2, ρ, and CCR of 0.64, -0.75, and 69%, respectively, and for NBD2 yielded R2, ρ, and CCR of 0.29, -0.27, and 50%, respectively. The corresponding numbers for the Rosetta's low-resolution protocol (Rosetta_lrp) were R2 = 0.47, ρ = -0.69, and CCR = 69% for NBD1 and R2 = 0.27, ρ = -0.24, and CCR = 63% for NBD2. For NBD1, both algorithms suggest that destabilizing mutations suffer from destabilizing vdW clashes, whereas stabilizing mutations benefit from favorable H-bond interactions. Two triple consensus approaches based on FoldX, Rosetta_lpr, and Rosetta_hpr were attempted using either "majority-voting" or "all-voting". The all-voting consensus outperformed the individual predictors, albeit on a smaller data set. In summary, our results suggest that the effect of mutations on the stability of CFTR's NBDs could be largely predicted. Since NBDs are common to all ABC transporters, these results may find use in predicting the effect and mechanism of the action of multiple disease-causing mutations in other proteins.
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Affiliation(s)
| | - Netaly Khazanov
- Department of Chemistry, Bar-Ilan University, Ramat-Gan, 5290002, Israel
| | - Qingxian Zhou
- School of Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, University of Alabama at Birmingham, Birmingham, Alabama 35294, United States
| | - Zhengrong Yang
- School of Medicine, Division of Hematology & Oncology, University of Alabama at Birmingham, Birmingham, Alabama 35294, United States
| | - Chi Wang
- 702 Fairchild Center, MC3423, Department of Biological Sciences, Columbia University, New York, New York 10027, United States
| | - Jeong S Hong
- Department of Paediatrics, Emory University School of Medicine, Atlanta, Georgia 30303, United States
| | - Andras Rab
- Department of Paediatrics, Emory University School of Medicine, Atlanta, Georgia 30303, United States
| | - Eric J Sorscher
- Department of Paediatrics, Emory University School of Medicine, Atlanta, Georgia 30303, United States
| | - Christie G Brouillette
- Department of Biochemistry & Molecular Genetics, University of Alabama at Birmingham, Birmingham, Alabama 35294, United States
| | - John F Hunt
- 702 Fairchild Center, MC3423, Department of Biological Sciences, Columbia University, New York, New York 10027, United States
| | - Hanoch Senderowitz
- Department of Chemistry, Bar-Ilan University, Ramat-Gan, 5290002, Israel
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6
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Beswick E, Amich J, Gago S. Factoring in the Complexity of the Cystic Fibrosis Lung to Understand Aspergillus fumigatus and Pseudomonas aeruginosa Interactions. Pathogens 2020; 9:pathogens9080639. [PMID: 32781694 PMCID: PMC7460534 DOI: 10.3390/pathogens9080639] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 07/25/2020] [Accepted: 08/04/2020] [Indexed: 02/07/2023] Open
Abstract
Pseudomonas aeruginosa has long been established as the most prevalent respiratory pathogen in Cystic Fibrosis (CF) patients, with opportunistic infection causing profound morbidity and mortality. Recently, Aspergillus fumigatus has also been recognised as a key contributor to CF lung deterioration, being consistently associated with decreased lung function and worsened prognosis in these patients. As clinical evidence for the common occurrence of combined infection with these two pathogens increases, research into the mechanism and consequences of their interaction is becoming more relevant. Clinical evidence suggests a synergistic effect of combined infection, which translates into a poorer prognosis for the patients. In vitro results from the laboratory have identified a variety of possible synergistic and antagonistic interactions between A. fumigatus and P. aeruginosa. Here, we present a comprehensive overview of the complex environment of the CF lung and discuss how it needs to be considered to determine the exact molecular interactions that A. fumigatus and P. aeruginosa undergo during combined infection and their effects on the host.
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Affiliation(s)
- Emily Beswick
- Manchester Fungal Infection Group, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Core Technology Facility, Grafton Street, Manchester M13 9NT, UK
- Academic Unit of Medical Education, Medical School, University of Sheffield, Beech Hill Road, Broomhall, Sheffield S10 2TG, UK;
| | - Jorge Amich
- Manchester Fungal Infection Group, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Core Technology Facility, Grafton Street, Manchester M13 9NT, UK
- Correspondence: (J.A.); (S.G.)
| | - Sara Gago
- Manchester Fungal Infection Group, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Core Technology Facility, Grafton Street, Manchester M13 9NT, UK
- Correspondence: (J.A.); (S.G.)
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7
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Meng X, Clews J, Ciuta AD, Martin ER, Ford RC. CFTR structure, stability, function and regulation. Biol Chem 2020; 400:1359-1370. [PMID: 30738013 DOI: 10.1515/hsz-2018-0470] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 01/30/2019] [Indexed: 12/15/2022]
Abstract
Cystic fibrosis transmembrane conductance regulator (CFTR) is a unique member of the ATP-binding cassette family of proteins because it has evolved into a channel. Mutations in CFTR cause cystic fibrosis, the most common genetic disease in people of European origin. The F508del mutation is found in about 90% of patients and here we present data that suggest its main effect is on CFTR stability rather than on the three-dimensional (3D) folded state. A survey of recent cryo-electron microscopy studies was carried out and this highlighted differences in terms of CFTR conformation despite similarities in experimental conditions. We further studied CFTR structure under various phosphorylation states and with the CFTR-interacting protein NHERF1. The coexistence of outward-facing and inward-facing conformations under a range of experimental conditions was suggested from these data. These results are discussed in terms of structural models for channel gating, and favour the model where the mostly disordered regulatory-region of the protein acts as a channel plug.
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Affiliation(s)
- Xin Meng
- School of Biological Sciences, Faculty of Biology Medicine and Health, Michael Smith Building, The University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Jack Clews
- School of Biological Sciences, Faculty of Biology Medicine and Health, Michael Smith Building, The University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Anca D Ciuta
- School of Biological Sciences, Faculty of Biology Medicine and Health, Michael Smith Building, The University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Eleanor R Martin
- School of Biological Sciences, Faculty of Biology Medicine and Health, Michael Smith Building, The University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Robert C Ford
- School of Biological Sciences, Faculty of Biology Medicine and Health, Michael Smith Building, The University of Manchester, Oxford Road, Manchester M13 9PL, UK
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8
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Ivey G, Youker RT. Disease-relevant mutations alter amino acid co-evolution networks in the second nucleotide binding domain of CFTR. PLoS One 2020; 15:e0227668. [PMID: 31978131 PMCID: PMC6980524 DOI: 10.1371/journal.pone.0227668] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2018] [Accepted: 12/25/2019] [Indexed: 01/23/2023] Open
Abstract
Cystic Fibrosis (CF) is an inherited disease caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) ion channel. Mutations in CFTR cause impaired chloride ion transport in the epithelial tissues of patients leading to cardiopulmonary decline and pancreatic insufficiency in the most severely affected patients. CFTR is composed of twelve membrane-spanning domains, two nucleotide-binding domains (NBDs), and a regulatory domain. The most common mutation in CFTR is a deletion of phenylalanine at position 508 (ΔF508) in NBD1. Previous research has primarily concentrated on the structure and dynamics of the NBD1 domain; However numerous pathological mutations have also been found in the lesser-studied NBD2 domain. We have investigated the amino acid co-evolved network of interactions in NBD2, and the changes that occur in that network upon the introduction of CF and CF-related mutations (S1251N(T), S1235R, D1270N, N1303K(T)). Extensive coupling between the α- and β-subdomains were identified with residues in, or near Walker A, Walker B, H-loop and C-loop motifs. Alterations in the predicted residue network varied from moderate for the S1251T perturbation to more severe for N1303T. The S1235R and D1270N networks varied greatly compared to the wildtype, but these CF mutations only affect ion transport preference and do not severely disrupt CFTR function, suggesting dynamic flexibility in the network of interactions in NBD2. Our results also suggest that inappropriate interactions between the β-subdomain and Q-loop could be detrimental. We also identified mutations predicted to stabilize the NBD2 residue network upon introduction of the CF and CF-related mutations, and these predicted mutations are scored as benign by the MUTPRED2 algorithm. Our results suggest the level of disruption of the co-evolution predictions of the amino acid networks in NBD2 does not have a straightforward correlation with the severity of the CF phenotypes observed.
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Affiliation(s)
- Gabrianne Ivey
- Kyder Christian Academy, Franklin, North Carolina, United States of America
- Southwestern Community College, Sylva, North Carolina, United States of America
| | - Robert T. Youker
- Department of Biology, Western Carolina University, Cullowhee, North Carolina, United States of America
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9
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Doonan LM, Guerriero CJ, Preston GM, Buck TM, Khazanov N, Fisher EA, Senderowitz H, Brodsky JL. Hsp104 facilitates the endoplasmic-reticulum-associated degradation of disease-associated and aggregation-prone substrates. Protein Sci 2019; 28:1290-1306. [PMID: 31050848 DOI: 10.1002/pro.3636] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Accepted: 04/29/2019] [Indexed: 12/20/2022]
Abstract
Misfolded proteins in the endoplasmic reticulum (ER) are selected for ER-associated degradation (ERAD). More than 60 disease-associated proteins are substrates for the ERAD pathway due to the presence of missense or nonsense mutations. In yeast, the Hsp104 molecular chaperone disaggregates detergent-insoluble ERAD substrates, but the spectrum of disease-associated ERAD substrates that may be aggregation prone is unknown. To determine if Hsp104 recognizes aggregation-prone ERAD substrates associated with human diseases, we developed yeast expression systems for a hydrophobic lipid-binding protein, apolipoprotein B (ApoB), along with a chimeric protein harboring a nucleotide-binding domain from the cystic fibrosis transmembrane conductance regulator (CFTR) into which disease-causing mutations were introduced. We discovered that Hsp104 facilitates the degradation of ER-associated ApoB as well as a truncated CFTR chimera in which a premature stop codon corresponds to a disease-causing mutation. Chimeras containing a wild-type version of the CFTR domain or a different mutation were stable and thus Hsp104 independent. We also discovered that the detergent solubility of the unstable chimera was lower than the stable chimeras, and Hsp104 helped retrotranslocate the unstable chimera from the ER, consistent with disaggregase activity. To determine why the truncated chimera was unstable, we next performed molecular dynamics simulations and noted significant unraveling of the CFTR nucleotide-binding domain. Because human cells lack Hsp104, these data indicate that an alternate disaggregase or mechanism facilitates the removal of aggregation-prone, disease-causing ERAD substrates in their native environments.
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Affiliation(s)
- Lynley M Doonan
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, 15260
| | - Christopher J Guerriero
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, 15260
| | - G Michael Preston
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, 15260
| | - Teresa M Buck
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, 15260
| | - Netaly Khazanov
- Department of Chemistry, Bar Ilan University, Ramat Gan, 5290002, Israel
| | - Edward A Fisher
- Division of Cardiology, Department of Medicine and Cell Biology, New York University, New York, New York, 10016
| | - Hanoch Senderowitz
- Department of Chemistry, Bar Ilan University, Ramat Gan, 5290002, Israel
| | - Jeffrey L Brodsky
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, 15260
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10
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Gong X, Liao Y, Ahner A, Larsen MB, Wang X, Bertrand CA, Frizzell RA. Different SUMO paralogues determine the fate of wild-type and mutant CFTRs: biogenesis versus degradation. Mol Biol Cell 2018; 30:4-16. [PMID: 30403549 PMCID: PMC6337916 DOI: 10.1091/mbc.e18-04-0252] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
A pathway for cystic fibrosis transmembrane conductance regulator (CFTR) degradation is initiated by Hsp27, which cooperates with Ubc9 and binds to the common F508del mutant to modify it with SUMO-2/3. These SUMO paralogues form polychains, which are recognized by the ubiquitin ligase, RNF4, for proteosomal degradation. Here, protein array analysis identified the SUMO E3, protein inhibitor of activated STAT 4 (PIAS4), which increased wild-type (WT) and F508del CFTR biogenesis in CFBE airway cells. PIAS4 increased immature CFTR threefold and doubled expression of mature CFTR, detected by biochemical and functional assays. In cycloheximide chase assays, PIAS4 slowed immature F508del degradation threefold and stabilized mature WT CFTR at the plasma membrance. PIAS4 knockdown reduced WT and F508del CFTR expression by 40–50%, suggesting a physiological role in CFTR biogenesis. PIAS4 modified F508del CFTR with SUMO-1 in vivo and reduced its conjugation to SUMO-2/3. These SUMO paralogue-specific effects of PIAS4 were reproduced in vitro using purified F508del nucleotide-binding domain 1 and SUMOylation reaction components. PIAS4 reduced endogenous ubiquitin conjugation to F508del CFTR by ∼50% and blocked the impact of RNF4 on mutant CFTR disposal. These findings indicate that different SUMO paralogues determine the fates of WT and mutant CFTRs, and they suggest that a paralogue switch during biogenesis can direct these proteins to different outcomes: biogenesis versus degradation.
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Affiliation(s)
- Xiaoyan Gong
- Departments of Pediatrics and Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15224
| | - Yong Liao
- Departments of Pediatrics and Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15224
| | - Annette Ahner
- Departments of Pediatrics and Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15224
| | - Mads Breum Larsen
- Departments of Pediatrics and Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15224
| | - Xiaohui Wang
- Departments of Pediatrics and Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15224
| | - Carol A Bertrand
- Departments of Pediatrics and Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15224
| | - Raymond A Frizzell
- Departments of Pediatrics and Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15224
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11
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Veit G, Xu H, Dreano E, Avramescu RG, Bagdany M, Beitel LK, Roldan A, Hancock MA, Lay C, Li W, Morin K, Gao S, Mak PA, Ainscow E, Orth AP, McNamara P, Edelman A, Frenkiel S, Matouk E, Sermet-Gaudelus I, Barnes WG, Lukacs GL. Structure-guided combination therapy to potently improve the function of mutant CFTRs. Nat Med 2018; 24:1732-1742. [PMID: 30297908 PMCID: PMC6301090 DOI: 10.1038/s41591-018-0200-x] [Citation(s) in RCA: 96] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Accepted: 08/08/2018] [Indexed: 12/17/2022]
Abstract
Available corrector drugs are unable to effectively rescue the folding defects of CFTR-ΔF508 (or CFTR-F508del), the most common disease-causing mutation of the cystic fibrosis transmembrane conductance regulator, a plasma membrane (PM) anion channel, and thus to substantially ameliorate clinical phenotypes of cystic fibrosis (CF). To overcome the corrector efficacy ceiling, here we show that compounds targeting distinct structural defects of CFTR can synergistically rescue mutant expression and function at the PM. High-throughput cell-based screens and mechanistic analysis identified three small-molecule series that target defects at nucleotide-binding domain (NBD1), NBD2 and their membrane-spanning domain (MSD) interfaces. Although individually these compounds marginally improve ΔF508-CFTR folding efficiency, function and stability, their combinations lead to ~50-100% of wild-type-level correction in immortalized and primary human airway epithelia and in mouse nasal epithelia. Likewise, corrector combinations were effective against rare missense mutations in various CFTR domains, probably acting via structural allostery, suggesting a mechanistic framework for their broad application.
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Affiliation(s)
- Guido Veit
- Department of Physiology, McGill University, Montréal, Quebec, Canada.
| | - Haijin Xu
- Department of Physiology, McGill University, Montréal, Quebec, Canada
| | - Elise Dreano
- Institut Necker-Enfants Malades (INEM)-INSERM U1151, Paris, France
| | - Radu G Avramescu
- Department of Physiology, McGill University, Montréal, Quebec, Canada
| | - Miklos Bagdany
- Department of Physiology, McGill University, Montréal, Quebec, Canada
| | - Lenore K Beitel
- Department of Physiology, McGill University, Montréal, Quebec, Canada
| | - Ariel Roldan
- Department of Physiology, McGill University, Montréal, Quebec, Canada
| | - Mark A Hancock
- SPR-MS Facility, McGill University, Montréal, Quebec, Canada
| | - Cecilia Lay
- Genomic Institute of the Novartis Research Foundation, San Diego, CA, USA
| | - Wei Li
- Genomic Institute of the Novartis Research Foundation, San Diego, CA, USA
| | - Katelin Morin
- Genomic Institute of the Novartis Research Foundation, San Diego, CA, USA
| | - Sandra Gao
- Genomic Institute of the Novartis Research Foundation, San Diego, CA, USA
| | - Puiying A Mak
- Genomic Institute of the Novartis Research Foundation, San Diego, CA, USA
| | - Edward Ainscow
- Genomic Institute of the Novartis Research Foundation, San Diego, CA, USA
| | - Anthony P Orth
- Genomic Institute of the Novartis Research Foundation, San Diego, CA, USA
| | - Peter McNamara
- Genomic Institute of the Novartis Research Foundation, San Diego, CA, USA
| | | | - Saul Frenkiel
- Department of Otolaryngology - Head and Neck Surgery, McGill University, Montréal, Quebec, Canada
| | - Elias Matouk
- Adult Cystic Fibrosis Clinic, Montreal Chest Institute, McGill University, Montréal, Quebec, Canada
| | | | - William G Barnes
- Genomic Institute of the Novartis Research Foundation, San Diego, CA, USA
| | - Gergely L Lukacs
- Department of Physiology, McGill University, Montréal, Quebec, Canada. .,Department of Biochemistry, McGill University, Montréal, Quebec, Canada. .,Groupe de Recherche Axé sur la Structure des Protéines (GRASP), McGill University, Montréal, Quebec, Canada.
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12
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Kumari S, Kumar M, Khandelwal NK, Kumari P, Varma M, Vishwakarma P, Shahi G, Sharma S, Lynn AM, Prasad R, Gaur NA. ABC transportome inventory of human pathogenic yeast Candida glabrata: Phylogenetic and expression analysis. PLoS One 2018; 13:e0202993. [PMID: 30153284 PMCID: PMC6112666 DOI: 10.1371/journal.pone.0202993] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 08/12/2018] [Indexed: 12/25/2022] Open
Abstract
ATP-binding cassette (ABC) is one of the two major superfamilies of transporters present across the evolutionary scale. ABC superfamily members came to prominence due to their ability to extrude broad spectrum of substrates and to confer multi drug resistance (MDR). Overexpression of some ABC transporters in clinical isolates of Candida species was attributed to the development of MDR phenotypes. Among Candida species, Candida glabrata is an emerging drug resistant species in human fungal infections. A comprehensive analysis of such proteins in C. glabrata is required to untangle their role not only in MDR but also in other biological processes. Bioinformatic analysis of proteins encoded by genome of human pathogenic yeast C. glabrata identified 25 putative ABC protein coding genes. On the basis of phylogenetic analysis, domain organization and nomenclature adopted by the Human Genome Organization (HUGO) scheme, these proteins were categorized into six subfamilies such as Pleiotropic Drug Resistance (PDR)/ABCG, Multi Drug Resistance (MDR)/ABCB, Multi Drug Resistance associated Protein (MRP)/ABCC, Adrenoleukodystrophy protein (ALDp)/ABCD, RNase L Inhibitor (RLI)/ABCE and Elongation Factor 3 (EF3)/ABCF. Among these, only 18 ABC proteins contained transmembrane domains (TMDs) and were grouped as membrane proteins, predominantly belonging to PDR, MDR, MRP, and ALDp subfamilies. A comparative phylogenetic analysis of these ABC proteins with other yeast species revealed their orthologous relationship and pointed towards their conserved functions. Quantitative real time PCR (qRT-PCR) analysis of putative membrane localized ABC protein encoding genes of C. glabrata confirmed their basal expression and showed variable transcriptional response towards antimycotic drugs. This study presents first comprehensive overview of ABC superfamily proteins of a human fungal pathogen C. glabrata, which is expected to provide an important platform for in depth analysis of their physiological relevance in cellular processes and drug resistance.
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Affiliation(s)
- Sonam Kumari
- Yeast Biofuel Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
| | - Mohit Kumar
- Yeast Biofuel Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
- Amity Institute of Integrative Science and Health, Amity University Gurgaon, Haryana, India
| | - Nitesh Kumar Khandelwal
- Yeast Biofuel Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
| | - Priya Kumari
- Yeast Biofuel Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
| | - Mahendra Varma
- Yeast Biofuel Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
| | - Poonam Vishwakarma
- School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Garima Shahi
- Amity Institute of Integrative Science and Health, Amity University Gurgaon, Haryana, India
| | - Suman Sharma
- Amity Institute of Integrative Science and Health, Amity University Gurgaon, Haryana, India
| | - Andrew M. Lynn
- School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Rajendra Prasad
- Amity Institute of Integrative Science and Health, Amity University Gurgaon, Haryana, India
| | - Naseem A. Gaur
- Yeast Biofuel Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
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13
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Ran Y, Zheng A, Thibodeau PH. Structural analysis reveals pathomechanisms associated with pseudoxanthoma elasticum-causing mutations in the ABCC6 transporter. J Biol Chem 2018; 293:15855-15866. [PMID: 30154241 DOI: 10.1074/jbc.ra118.004806] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Revised: 08/23/2018] [Indexed: 11/06/2022] Open
Abstract
Mutations in ABC subfamily C member 6 (ABCC6) transporter are associated with pseudoxanthoma elasticum (PXE), a disease resulting in ectopic mineralization and affecting multiple tissues. A growing number of mutations have been identified in individuals with PXE. For most of these variants, no mechanistic information is available regarding their role in normal and pathophysiologies. To assess how PXE-associated mutations alter ABCC6 biosynthesis and structure, we biophysically and biochemically evaluated the N-terminal nucleotide-binding domain. A high-resolution X-ray structure of nucleotide-binding domain 1 (NBD1) of human ABCC6 was obtained at 2.3 Å that provided a template on which to evaluate PXE-causing mutations. Biochemical analysis of mutations in this domain indicated that multiple PXE-causing mutations altered its structural properties. Analyses of the full-length protein revealed a strong correlation between the alterations in NBD properties and the processing and expression of ABCC6. These results suggest that a significant fraction of PXE-associated mutations located in NBD1 causes changes in its structural properties and that these mutation-induced alterations directly affect the maturation of the full-length ABCC6 protein.
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Affiliation(s)
- Yanchao Ran
- From the Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15219
| | - Aiping Zheng
- From the Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15219
| | - Patrick H Thibodeau
- From the Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15219
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14
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Yang Z, Hildebrandt E, Jiang F, Aleksandrov AA, Khazanov N, Zhou Q, An J, Mezzell AT, Xavier BM, Ding H, Riordan JR, Senderowitz H, Kappes JC, Brouillette CG, Urbatsch IL. Structural stability of purified human CFTR is systematically improved by mutations in nucleotide binding domain 1. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:1193-1204. [PMID: 29425673 DOI: 10.1016/j.bbamem.2018.02.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 01/19/2018] [Accepted: 02/05/2018] [Indexed: 12/17/2022]
Abstract
The Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) is an ABC transporter containing two transmembrane domains forming a chloride ion channel, and two nucleotide binding domains (NBD1 and NBD2). CFTR has presented a formidable challenge to obtain monodisperse, biophysically stable protein. Here we report a comprehensive study comparing effects of single and multiple NBD1 mutations on stability of both the NBD1 domain alone and on purified full length human CFTR. Single mutations S492P, A534P, I539T acted additively, and when combined with M470V, S495P, and R555K cumulatively yielded an NBD1 with highly improved structural stability. Strategic combinations of these mutations strongly stabilized the domain to attain a calorimetric Tm > 70 °C. Replica exchange molecular dynamics simulations on the most stable 6SS-NBD1 variant implicated fluctuations, electrostatic interactions and side chain packing as potential contributors to improved stability. Progressive stabilization of NBD1 directly correlated with enhanced structural stability of full-length CFTR protein. Thermal unfolding of the stabilized CFTR mutants, monitored by changes in intrinsic fluorescence, demonstrated that Tm could be shifted as high as 67.4 °C in 6SS-CFTR, more than 20 °C higher than wild-type. H1402S, an NBD2 mutation, conferred CFTR with additional thermal stability, possibly by stabilizing an NBD-dimerized conformation. CFTR variants with NBD1-stabilizing mutations were expressed at the cell surface in mammalian cells, exhibited ATPase and channel activity, and retained these functions to higher temperatures. The capability to produce enzymatically active CFTR with improved structural stability amenable to biophysical and structural studies will advance mechanistic investigations and future cystic fibrosis drug development.
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Affiliation(s)
- Zhengrong Yang
- Department of Chemistry, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Ellen Hildebrandt
- Department of Cell Biology and Biochemistry, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, 3601 4th Street, Stop 6540, Lubbock, TX 79430, USA
| | - Fan Jiang
- Department of Medicine, University of Alabama at Birmingham, 701 19th Street South, Birmingham, AL 35294-0007, USA
| | - Andrei A Aleksandrov
- Department of Biochemistry and Biophysics and Cystic Fibrosis Treatment and Research Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Netaly Khazanov
- Department of Chemistry, Bar-Ilan University, Ramat-Gan, 5290002, Israel
| | - Qingxian Zhou
- Department of Chemistry, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Jianli An
- Department of Chemistry, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Andrew T Mezzell
- Department of Medicine, University of Alabama at Birmingham, 701 19th Street South, Birmingham, AL 35294-0007, USA
| | - Bala M Xavier
- Department of Cell Biology and Biochemistry, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, 3601 4th Street, Stop 6540, Lubbock, TX 79430, USA
| | - Haitao Ding
- Department of Medicine, University of Alabama at Birmingham, 701 19th Street South, Birmingham, AL 35294-0007, USA
| | - John R Riordan
- Department of Biochemistry and Biophysics and Cystic Fibrosis Treatment and Research Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Hanoch Senderowitz
- Department of Chemistry, Bar-Ilan University, Ramat-Gan, 5290002, Israel
| | - John C Kappes
- Department of Medicine, University of Alabama at Birmingham, 701 19th Street South, Birmingham, AL 35294-0007, USA; Birmingham Veterans Affairs Medical Center, Research Service, Birmingham, AL 35233, USA
| | | | - Ina L Urbatsch
- Department of Cell Biology and Biochemistry, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, 3601 4th Street, Stop 6540, Lubbock, TX 79430, USA.
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15
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Callebaut I, Chong PA, Forman-Kay JD. CFTR structure. J Cyst Fibros 2017; 17:S5-S8. [PMID: 28866450 DOI: 10.1016/j.jcf.2017.08.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 08/06/2017] [Accepted: 08/16/2017] [Indexed: 02/08/2023]
Abstract
Structural studies of the cystic fibrosis transmembrane conductance regulator (CFTR) protein are critical to understand molecular mechanisms involved in gating of the apical anion channel as well as the way in which the gating is regulated, especially by the regulatory region (R region). They are also instrumental for understanding the root cause of cystic fibrosis (CF) and supporting the development of therapeutic strategies. In this short review, we summarize recent progress in the knowledge of the CFTR 3D structure and briefly discuss implications for CF drug development.
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Affiliation(s)
- Isabelle Callebaut
- IMPMC, Sorbonne Universités - UPMC Université Paris 06, UMR CNRS 7590, Muséum National d'Histoire Naturelle, IRD UMR 206, 4 Place Jussieu, Paris, France.
| | - P Andrew Chong
- Molecular Medicine, The Hospital for Sick Children, Toronto M5G 0A4, Canada
| | - Julie D Forman-Kay
- Molecular Medicine, The Hospital for Sick Children, Toronto M5G 0A4, Canada; Department of Biochemistry, University of Toronto, Toronto M5G 1X8, Canada
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