1
|
Gao X, Yeh HI, Yang Z, Fan C, Jiang F, Howard RJ, Lindahl E, Kappes JC, Hwang TC. Allosteric inhibition of CFTR gating by CFTRinh-172 binding in the pore. Nat Commun 2024; 15:6668. [PMID: 39107303 PMCID: PMC11303713 DOI: 10.1038/s41467-024-50641-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Accepted: 07/09/2024] [Indexed: 08/10/2024] Open
Abstract
Loss-of-function mutations of the CFTR gene cause the life-shortening genetic disease cystic fibrosis (CF), whereas overactivity of CFTR may lead to secretory diarrhea and polycystic kidney disease. While effective drugs targeting the CFTR protein have been developed for the treatment of CF, little progress has been made for diseases caused by hyper-activated CFTR. Here, we solve the cryo-EM structure of CFTR in complex with CFTRinh-172 (Inh-172), a CFTR gating inhibitor with promising potency and efficacy. We find that Inh-172 binds inside the pore of CFTR, interacting with amino acid residues from transmembrane segments (TMs) 1, 6, 8, 9, and 12 through mostly hydrophobic interactions and a salt bridge. Substitution of these residues lowers the apparent affinity of Inh-172. The inhibitor-bound structure reveals re-orientations of the extracellular segment of TMs 1, 8, and 12, supporting an allosteric modulation mechanism involving post-binding conformational changes. This allosteric inhibitory mechanism readily explains our observations that pig CFTR, which preserves all the amino acid residues involved in Inh-172 binding, exhibits a much-reduced sensitivity to Inh-172 and that the apparent affinity of Inh-172 is altered by the CF drug ivacaftor (i.e., VX-770) which enhances CFTR's activity through binding to a site also comprising TM8.
Collapse
Affiliation(s)
- Xiaolong Gao
- Dalton Cardiovascular Research Center, University of Missouri-Columbia, Columbia, MO, 65211, USA.
| | - Han-I Yeh
- Dalton Cardiovascular Research Center, University of Missouri-Columbia, Columbia, MO, 65211, USA
- Institute of Pharmacology, National Yang Ming Chiao Tung University, College of Medicine, Taipei, Taiwan
- Membrane Protein Structural Biology Research Center, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Zhengrong Yang
- Heersink School of Medicine, University of Alabama School of Medicine, Birmingham, AL, 35233, USA
| | - Chen Fan
- Department of Applied Physics, Science for Life Laboratory, KTH Royal Institute of Technology, Solna, Sweden
- Department of Biochemistry and Biophysics, Science for Life Laboratory, Stockholm University, Solna, Sweden
| | - Fan Jiang
- Heersink School of Medicine, University of Alabama School of Medicine, Birmingham, AL, 35233, USA
| | - Rebecca J Howard
- Department of Applied Physics, Science for Life Laboratory, KTH Royal Institute of Technology, Solna, Sweden
- Department of Biochemistry and Biophysics, Science for Life Laboratory, Stockholm University, Solna, Sweden
| | - Erik Lindahl
- Department of Applied Physics, Science for Life Laboratory, KTH Royal Institute of Technology, Solna, Sweden
- Department of Biochemistry and Biophysics, Science for Life Laboratory, Stockholm University, Solna, Sweden
| | - John C Kappes
- Heersink School of Medicine, University of Alabama School of Medicine, Birmingham, AL, 35233, USA
- Research Service, Birmingham Veterans Affairs Medical Center, Veterans Health Administration, Birmingham, AL, 35233, USA
| | - Tzyh-Chang Hwang
- Dalton Cardiovascular Research Center, University of Missouri-Columbia, Columbia, MO, 65211, USA.
- Institute of Pharmacology, National Yang Ming Chiao Tung University, College of Medicine, Taipei, Taiwan.
- Membrane Protein Structural Biology Research Center, National Yang Ming Chiao Tung University, Taipei, Taiwan.
| |
Collapse
|
2
|
Anwar S, Peng JL, Zahid KR, Zhou YM, Ali Q, Qiu CR. Cystic Fibrosis: Understanding Cystic Fibrosis Transmembrane Regulator Mutation Classification and Modulator Therapies. Adv Respir Med 2024; 92:263-277. [PMID: 39051188 PMCID: PMC11270331 DOI: 10.3390/arm92040026] [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: 05/02/2024] [Revised: 07/16/2024] [Accepted: 07/17/2024] [Indexed: 07/27/2024]
Abstract
A common life-threatening hereditary disease, Cystic Fibrosis (CF), affects primarily Caucasian infants. High sweat-salt levels are observed as a result of a single autosomal mutation in chromosome 7 that affects the critical function of the cystic fibrosis transmembrane regulator (CFTR). For establishing tailored treatment strategies, it is important to understand the broad range of CFTR mutations and their impacts on disease pathophysiology. This study thoroughly investigates the six main classes of classification of CFTR mutations based on their functional effects. Each class is distinguished by distinct molecular flaws, such as poor protein synthesis, misfolding, gating defects, conduction defects, and decreased CFTR expression at the apical membrane. Furthermore, this paper focuses on the emerging field of CFTR modulators, which intend to restore CFTR function or mitigate its consequences. These modulators, which are characterized by the mode of action and targeted mutation class, have the potential to provide personalized therapy regimens in CF patients. This review provides valuable insights into the genetic basis of CF pathology, and highlights the potential for precision medicine methods in CF therapy by thoroughly investigating CFTR mutation classification and related modulators.
Collapse
Affiliation(s)
- Saba Anwar
- Centre for Applied Molecular Biology, University of the Punjab Lahore, Lahore 53700, Pakistan;
| | - Jin-Liang Peng
- Department of Emergency, The Affiliated Ganzhou Hospital of Nanchang University, Ganzhou 341000, China; (J.-L.P.); (Y.-M.Z.)
| | - Kashif Rafiq Zahid
- Department of Radiation Oncology, Melvin and Bren Simon Comprehensive Cancer Center, Indiana University School of Medicine, Indianaapolis, IN 46202, USA;
| | - Yu-Ming Zhou
- Department of Emergency, The Affiliated Ganzhou Hospital of Nanchang University, Ganzhou 341000, China; (J.-L.P.); (Y.-M.Z.)
| | - Qurban Ali
- Department of Plant Breeding and Genetics, Faculty of Agricultural Sciences, University of the Punjab, Lahore 54590, Pakistan
| | - Chong-Rong Qiu
- Department of Emergency, The Affiliated Ganzhou Hospital of Nanchang University, Ganzhou 341000, China; (J.-L.P.); (Y.-M.Z.)
| |
Collapse
|
3
|
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.
Collapse
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
| |
Collapse
|
4
|
Han Y, Zhao J, Liu W, Yang X, Zhang W, Xiao X, Liu X, Chen X, Tang L, Wang P, Ge W. Increased prevalence of CFTR variants and susceptibility to CRS: A real-world study based on Chinese children. Heliyon 2024; 10:e27681. [PMID: 38590877 PMCID: PMC10999871 DOI: 10.1016/j.heliyon.2024.e27681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 03/02/2024] [Accepted: 03/05/2024] [Indexed: 04/10/2024] Open
Abstract
Background Chronic Rhinosinusitis is a common disease in children. The main function of CFTR is to maintain the thickness of the mucous layer on the surface of the nasal mucosa. CFTR disease-causing variant can cause CFTR protein dysfunction and induce or aggravate chronic infection. However, the carrying status of the CFTR variants in the Chinese population is not clear. Objective To study the frequency and variants of CFTR in Chinese children with CRS and to analyze the CFTR variants and the clinical characteristics and susceptibility to CRS. Methods Whole Exome Sequencing was performed to analyze the CFTR genes in a total of 106 CRS children from the Chinese mainland area. The CFTR variants, frequency and clinical data were summarized and analyzed. Results A total of 31 CFTR variants were detected, of which the carrying rate of 7 sites was significantly higher than that of the population database. 88 patients carried more than 2 variants. 37 people carried variants (MAF < 0.05), of which 91.89% had a history of recurrent upper respiratory infections, 16 had nasal polyps, 5 had bronchiectasis, and 1 was diagnosed with CF-related disorders. Conclusion The carrying rate of CFTR variants in Chinese CRS children increased, and the highest rates of variants (MAF < 0.05) are p.I556V, p. E217G, c.1210-12[T]. Carrying multiple CFTR variants, especially p.E217G, p.I807 M, p.V920L and c.1210-12[T] may lead to increased susceptibility to CRS. There are CF-related disorders in patients with CRS.
Collapse
Affiliation(s)
- Yang Han
- Department of Otolaryngology, Head and Neck Surgery, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, 100045, China
| | - Jinhao Zhao
- Department of Otolaryngology, Head and Neck Surgery, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, 100045, China
| | - Wenjing Liu
- Department of Otolaryngology, Head and Neck Surgery, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, 100045, China
| | - Xiaojian Yang
- Department of Otolaryngology, Head and Neck Surgery, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, 100045, China
| | - Wei Zhang
- Department of Otolaryngology, Head and Neck Surgery, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, 100045, China
| | - Xiao Xiao
- Department of Otolaryngology, Head and Neck Surgery, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, 100045, China
| | - Xiaoge Liu
- Department of Otolaryngology, Head and Neck Surgery, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, 100045, China
| | - Xiaoxu Chen
- Department of Otolaryngology, Head and Neck Surgery, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, 100045, China
| | - Lixing Tang
- Department of Otolaryngology, Head and Neck Surgery, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, 100045, China
| | - Pengpeng Wang
- Department of Otolaryngology, Head and Neck Surgery, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, 100045, China
| | - Wentong Ge
- Department of Otolaryngology, Head and Neck Surgery, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, 100045, China
- Beijing Key Laboratory for Pediatric Diseases of Otolaryngology, Head and Neck Surgery, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, 100045, China
| |
Collapse
|
5
|
Young PG, Levring J, Fiedorczuk K, Blanchard SC, Chen J. Structural basis for CFTR inhibition by CFTR inh-172. Proc Natl Acad Sci U S A 2024; 121:e2316675121. [PMID: 38422021 DOI: 10.1073/pnas.2316675121] [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: 09/25/2023] [Accepted: 01/12/2024] [Indexed: 03/02/2024] Open
Abstract
The cystic fibrosis transmembrane conductance regulator (CFTR) is an anion channel that regulates electrolyte and fluid balance in epithelial tissues. While activation of CFTR is vital to treating cystic fibrosis, selective inhibition of CFTR is a potential therapeutic strategy for secretory diarrhea and autosomal dominant polycystic kidney disease. Although several CFTR inhibitors have been developed by high-throughput screening, their modes of action remain elusive. In this study, we determined the structure of CFTR in complex with the inhibitor CFTRinh-172 to an overall resolution of 2.7 Å by cryogenic electron microscopy. We observe that CFTRinh-172 binds inside the pore near transmembrane helix 8, a critical structural element that links adenosine triphosphate hydrolysis with channel gating. Binding of CFTRinh-172 stabilizes a conformation in which the chloride selectivity filter is collapsed, and the pore is blocked from the extracellular side of the membrane. Single-molecule fluorescence resonance energy transfer experiments indicate that CFTRinh-172 inhibits channel gating without compromising nucleotide-binding domain dimerization. Together, these data reconcile previous biophysical observations and provide a molecular basis for the activity of this widely used CFTR inhibitor.
Collapse
Affiliation(s)
- Paul G Young
- Laboratory of Membrane Biology and Biophysics, The Rockefeller University, New York, NY 10065
- Weill Cornell/Rockefeller/Sloan Kettering Tri-Institutional MD-PhD Program, New York, NY 10065
| | - Jesper Levring
- Laboratory of Membrane Biology and Biophysics, The Rockefeller University, New York, NY 10065
| | - Karol Fiedorczuk
- Laboratory of Membrane Biology and Biophysics, The Rockefeller University, New York, NY 10065
| | - Scott C Blanchard
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38101
| | - Jue Chen
- Laboratory of Membrane Biology and Biophysics, The Rockefeller University, New York, NY 10065
- HHMI, The Rockefeller University, New York, NY 10065
| |
Collapse
|
6
|
Thakur S, Ankita, Dash S, Verma R, Kaur C, Kumar R, Mazumder A, Singh G. Understanding CFTR Functionality: A Comprehensive Review of Tests and Modulator Therapy in Cystic Fibrosis. Cell Biochem Biophys 2024; 82:15-34. [PMID: 38048024 DOI: 10.1007/s12013-023-01200-w] [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: 10/11/2023] [Accepted: 11/13/2023] [Indexed: 12/05/2023]
Abstract
Cystic fibrosis is a genetic disorder inherited in an autosomal recessive manner. It is caused by a mutation in the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) gene on chromosome 7, which leads to abnormal regulation of chloride and bicarbonate ions in cells that line organs like the lungs and pancreas. The CFTR protein plays a crucial role in regulating chloride ion flow, and its absence or malfunction causes the production of thick mucus that affects several organs. There are more than 2000 identified mutations that are classified into seven categories based on their dysfunction mechanisms. In this article, we have conducted a thorough examination and consolidation of the diverse array of tests essential for the quantification of CFTR functionality. Furthermore, we have engaged in a comprehensive discourse regarding the recent advancements in CFTR modulator therapy, a pivotal approach utilized for the management of cystic fibrosis, alongside its concomitant relevance in evaluating CFTR functionality.
Collapse
Affiliation(s)
- Shorya Thakur
- School of Pharmaceutical Sciences, Lovely Professional University, Phagwara, Panjab, India
| | - Ankita
- School of Pharmaceutical Sciences, Lovely Professional University, Phagwara, Panjab, India
| | - Shubham Dash
- School of Pharmaceutical Sciences, Lovely Professional University, Phagwara, Panjab, India
| | - Rupali Verma
- School of Pharmaceutical Sciences, Lovely Professional University, Phagwara, Panjab, India
| | - Charanjit Kaur
- School of Pharmaceutical Sciences, Lovely Professional University, Phagwara, Panjab, India
| | - Rajesh Kumar
- School of Pharmaceutical Sciences, Lovely Professional University, Phagwara, Panjab, India
| | - Avijit Mazumder
- Noida Institute of Engineering and Technology (Pharmacy Institute), Greater Noida, UP, India
| | - Gurvinder Singh
- School of Pharmaceutical Sciences, Lovely Professional University, Phagwara, Panjab, India.
| |
Collapse
|
7
|
Levring J, Chen J. Structural identification of a selectivity filter in CFTR. Proc Natl Acad Sci U S A 2024; 121:e2316673121. [PMID: 38381791 PMCID: PMC10907310 DOI: 10.1073/pnas.2316673121] [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: 09/25/2023] [Accepted: 01/19/2024] [Indexed: 02/23/2024] Open
Abstract
The cystic fibrosis transmembrane conductance regulator (CFTR) is a chloride channel that regulates transepithelial salt and fluid homeostasis. CFTR dysfunction leads to reduced chloride secretion into the mucosal lining of epithelial tissues, thereby causing the inherited disease cystic fibrosis. Although several structures of CFTR are available, our understanding of the ion-conduction pathway is incomplete. In particular, the route that connects the cytosolic vestibule with the extracellular space has not been clearly defined, and the structure of the open pore remains elusive. Furthermore, although many residues have been implicated in altering the selectivity of CFTR, the structure of the "selectivity filter" has yet to be determined. In this study, we identify a chloride-binding site at the extracellular ends of transmembrane helices 1, 6, and 8, where a dehydrated chloride is coordinated by residues G103, R334, F337, T338, and Y914. Alterations to this site, consistent with its function as a selectivity filter, affect ion selectivity, conductance, and open channel block. This selectivity filter is accessible from the cytosol through a large inner vestibule and opens to the extracellular solvent through a narrow portal. The identification of a chloride-binding site at the intra- and extracellular bridging point leads us to propose a complete conductance path that permits dehydrated chloride ions to traverse the lipid bilayer.
Collapse
Affiliation(s)
- Jesper Levring
- Laboratory of Membrane Biology and Biophysics, The Rockefeller University, New York, NY10065
| | - Jue Chen
- Laboratory of Membrane Biology and Biophysics, The Rockefeller University, New York, NY10065
- HHMI, The Rockefeller University, New York, NY10065
| |
Collapse
|
8
|
Li H, Rodrat M, Al-Salmani MK, Veselu DF, Han ST, Raraigh KS, Cutting GR, Sheppard DN. Two rare variants that affect the same amino acid in CFTR have distinct responses to ivacaftor. J Physiol 2024; 602:333-354. [PMID: 38186087 PMCID: PMC10872379 DOI: 10.1113/jp285727] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Accepted: 12/11/2023] [Indexed: 01/09/2024] Open
Abstract
Some residues in the cystic fibrosis transmembrane conductance regulator (CFTR) channel are the site of more than one CFTR variant that cause cystic fibrosis. Here, we investigated the function of S1159F and S1159P, two variants associated with different clinical phenotypes, which affect the same pore-lining residue in transmembrane segment 12 that are both strongly potentiated by ivacaftor when expressed in CFBE41o- bronchial epithelial cells. To study the single-channel behaviour of CFTR, we applied the patch-clamp technique to Chinese hamster ovary cells heterologously expressing CFTR variants incubated at 27°C to enhance channel residence at the plasma membrane. S1159F- and S1159P-CFTR formed Cl- channels activated by cAMP-dependent phosphorylation and gated by ATP that exhibited thermostability at 37°C. Both variants modestly reduced the single-channel conductance of CFTR. By severely attenuating channel gating, S1159F- and S1159P-CFTR reduced the open probability (Po ) of wild-type CFTR by ≥75% at ATP (1 mM); S1159F-CFTR caused the greater decrease in Po consistent with its more severe clinical phenotype. Ivacaftor (10-100 nM) doubled the Po of both CFTR variants without restoring Po values to wild-type levels, but concomitantly, ivacaftor decreased current flow through open channels. For S1159F-CFTR, the reduction of current flow was marked at high (supersaturated) ivacaftor concentrations (0.5-1 μM) and voltage-independent, identifying an additional detrimental action of elevated ivacaftor concentrations. In conclusion, S1159F and S1159P are gating variants, which also affect CFTR processing and conduction, but not stability, necessitating the use of combinations of CFTR modulators to optimally restore their channel activity. KEY POINTS: Dysfunction of the ion channel cystic fibrosis transmembrane conductance regulator (CFTR) causes the genetic disease cystic fibrosis (CF). This study investigated two rare pathogenic CFTR variants, S1159F and S1159P, which affect the same amino acid in CFTR, to understand the molecular basis of disease and response to the CFTR-targeted therapy ivacaftor. Both rare variants diminished CFTR function by modestly reducing current flow through the channel and severely inhibiting ATP-dependent channel gating with S1159F exerting the stronger adverse effect, which correlates with its association with more severe disease. Ivacaftor potentiated channel gating by both rare variants without restoring their activity to wild-type levels, but concurrently reduced current flow through open channels, particularly those of S1159F-CFTR. Our data demonstrate that S1159F and S1159P cause CFTR dysfunction by multiple mechanisms that require combinations of CFTR-targeted therapies to fully restore channel function.
Collapse
Affiliation(s)
- Hongyu Li
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK
| | - Mayuree Rodrat
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK
- Center of Research and Development for Biomedical Instrumentation, Institute of Molecular Biosciences, Mahidol University, Nakhon Pathom, Thailand
| | - Majid K Al-Salmani
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK
- Department of Physiology, College of Medicine and Health Sciences, Sultan Qaboos University, Al Khoudh, Muscat, Sultanate of Oman
| | | | - Sangwoo T Han
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Karen S Raraigh
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Garry R Cutting
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - David N Sheppard
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK
| |
Collapse
|
9
|
Yeh HI, Sutcliffe KJ, Sheppard DN, Hwang TC. CFTR Modulators: From Mechanism to Targeted Therapeutics. Handb Exp Pharmacol 2024; 283:219-247. [PMID: 35972584 DOI: 10.1007/164_2022_597] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
People with cystic fibrosis (CF) suffer from a multi-organ disorder caused by loss-of-function variants in the gene encoding the epithelial anion channel cystic fibrosis transmembrane conductance regulator (CFTR). Tremendous progress has been made in both basic and clinical sciences over the past three decades since the identification of the CFTR gene. Over 90% of people with CF now have access to therapies targeting dysfunctional CFTR. This success was made possible by numerous studies in the field that incrementally paved the way for the development of small molecules known as CFTR modulators. The advent of CFTR modulators transformed this life-threatening illness into a treatable disease by directly binding to the CFTR protein and correcting defects induced by pathogenic variants. In this chapter, we trace the trajectory of structural and functional studies that brought CF therapies from bench to bedside, with an emphasis on mechanistic understanding of CFTR modulators.
Collapse
Affiliation(s)
- Han-I Yeh
- Department of Pharmacology, National Yang Ming Chiao Tung University, Taipei City, Taiwan
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, USA
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO, USA
| | - Katy J Sutcliffe
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK
| | - David N Sheppard
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK
| | - Tzyh-Chang Hwang
- Department of Pharmacology, National Yang Ming Chiao Tung University, Taipei City, Taiwan.
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, USA.
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO, USA.
| |
Collapse
|
10
|
Liu Y, Xia D, Zhong L, Chen L, Zhang L, Ai M, Mei R, Pang R. Casein Kinase 2 Affects Epilepsy by Regulating Ion Channels: A Potential Mechanism. CNS & NEUROLOGICAL DISORDERS DRUG TARGETS 2024; 23:894-905. [PMID: 37350003 DOI: 10.2174/1871527322666230622124618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 03/31/2023] [Accepted: 04/10/2023] [Indexed: 06/24/2023]
Abstract
Epilepsy, characterized by recurrent seizures and abnormal brain discharges, is the third most common chronic disorder of the Central Nervous System (CNS). Although significant progress has been made in the research on antiepileptic drugs (AEDs), approximately one-third of patients with epilepsy are refractory to these drugs. Thus, research on the pathogenesis of epilepsy is ongoing to find more effective treatments. Many pathological mechanisms are involved in epilepsy, including neuronal apoptosis, mossy fiber sprouting, neuroinflammation, and dysfunction of neuronal ion channels, leading to abnormal neuronal excitatory networks in the brain. CK2 (Casein kinase 2), which plays a critical role in modulating neuronal excitability and synaptic transmission, has been shown to be associated with epilepsy. However, there is limited research on the mechanisms involved. Recent studies have suggested that CK2 is involved in regulating the function of neuronal ion channels by directly phosphorylating them or their binding partners. Therefore, in this review, we will summarize recent research advances regarding the potential role of CK2 regulating ion channels in epilepsy, aiming to provide more evidence for future studies.
Collapse
Affiliation(s)
- Yan Liu
- Department of Neurology, the First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan, 650032, China
| | - Di Xia
- Department of Neurology, the First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan, 650032, China
| | - Lianmei Zhong
- Department of Neurology, the First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan, 650032, China
| | - Ling Chen
- Department of Neurology, the First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan, 650032, China
- Yunnan Provincial Clinical Research Center for Neurological Disease, Kunming, Yunnan, 650032, China
| | - Linming Zhang
- Department of Neurology, the First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan, 650032, China
| | - Mingda Ai
- Department of Neurology, the First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan, 650032, China
| | - Rong Mei
- Department of Neurology, the First People's Hospital of Yunnan Province, Kunming, Yunnan, 650034, China
| | - Ruijing Pang
- Department of Neurology, the First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan, 650032, China
| |
Collapse
|
11
|
Linsdell P. Role of Hydrophobic Amino-Acid Side-Chains in the Narrow Selectivity Filter of the CFTR Chloride Channel Pore in Conductance and Selectivity. J Membr Biol 2023; 256:433-442. [PMID: 37823914 DOI: 10.1007/s00232-023-00294-w] [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: 04/26/2023] [Accepted: 09/26/2023] [Indexed: 10/13/2023]
Abstract
Cystic fibrosis is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) anion channel. Structural analysis of CFTR has identified a narrow, hydrophobic region close to the extracellular end of the open channel pore that may function as a selectivity filter. The present study combines comprehensive mutagenesis of hydrophobic amino-acid side-chains within the selectivity filter with functional evaluation of channel Cl- conductance and anion selectivity. Among these hydrophobic amino-acids, one (F337) appears to play a dominant role in determining both conductance and selectivity. Anion selectivity appears to depend on both side-chain size and hydrophobicity at this position. In contrast, conductance is disrupted by all F337 mutations, suggesting that unique interactions between permeating Cl- ions and the native phenylalanine side-chain are important for conductance. Surprisingly, a positively charged lysine side-chain can be substituted for several hydrophobic residues within the selectivity filter (including F337) with only minor changes in pore function, arguing against a crucial role for overall hydrophobicity. These results suggest that localized interactions between permeating anions and amino-acid side-chains within the selectivity filter may be more important in determining pore functional properties than are global features such as overall hydrophobicity.
Collapse
Affiliation(s)
- Paul Linsdell
- Department of Physiology & Biophysics, Dalhousie University, PO Box 15000, Halifax, NS, B3H 4R2, Canada.
| |
Collapse
|
12
|
Shengjia S, Lei W, Tianwei W, Hongmei W, Juanzi S, Sen Q. Compound heterozygous variants in CFTR with potentially reducing ATP-binding ability identified in Chinese infertile brothers with isolated congenital bilateral absence of vas deferens. Mol Genet Genomic Med 2023; 11:e2249. [PMID: 37489040 PMCID: PMC10655520 DOI: 10.1002/mgg3.2249] [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: 02/28/2023] [Revised: 03/23/2023] [Accepted: 07/13/2023] [Indexed: 07/26/2023] Open
Abstract
BACKGROUND Isolated congenital bilateral absence of vas deferens (iCBAVD) in men results in obstructive azoospermia and is mainly caused by pathogenic variants in cystic fibrosis transmembrane conductance regulator (CFTR) or adhesion G protein-coupled receptor G2 (ADGRG2). METHODS The next-generation sequencing (NGS) was used to screen the mutations in the proband, and Sanger sequencings were performed to validate the compound heterozygous variant of CFTR in his family members. Protein structure simulation was performed to discover the potential pathological mechanism. RESULTS This study reported novel compound heterozygous CFTR mutations (NM:000492.4, Intron: 5T; c.3965_3969dupTTGGG: p.R1325Gfs*5) in two brothers with obstructive azoospermia. The compound heterozygous CFTR mutations were first screened out by NGS in an infertile male patient who exhibited iCBAVD from a nonconsanguineous Chinese family. Histological analysis of the testicular biopsy from this patient revealed normal spermatogenesis and mature spermatozoa were observed in the seminiferous tubules. Surprisingly, the same compound heterozygous CFTR mutations were also observed in his brothers who also exhibited iCBAVD, with their parents being a heterozygous carrier for the mutations, as verified by Sanger sequencing. Protein structure simulation revealed that these mutations potentially led to impaired ATP-binding ability of CFTR. CONCLUSION We identified novel compound heterozygous CFTR mutations in two brothers and summarized the literature regarding CFTR mutation and male infertility. Our study may contribute to the genetic diagnosis of iCBAVD and future genetic counseling.
Collapse
Affiliation(s)
- Shi Shengjia
- Reproductive CenterNorthwest Women's and Children's HospitalXi'anChina
| | - Wang Lei
- Reproductive CenterNorthwest Women's and Children's HospitalXi'anChina
| | - Wang Tianwei
- Reproductive CenterNorthwest Women's and Children's HospitalXi'anChina
| | - Wang Hongmei
- School of MedicineSoutheast UniversityNanjingChina
| | - Shi Juanzi
- Reproductive CenterNorthwest Women's and Children's HospitalXi'anChina
| | - Qiao Sen
- Reproductive CenterNorthwest Women's and Children's HospitalXi'anChina
| |
Collapse
|
13
|
McDonald EF, Meiler J, Plate L. CFTR Folding: From Structure and Proteostasis to Cystic Fibrosis Personalized Medicine. ACS Chem Biol 2023; 18:2128-2143. [PMID: 37730207 PMCID: PMC10595991 DOI: 10.1021/acschembio.3c00310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 08/02/2023] [Indexed: 09/22/2023]
Abstract
Cystic fibrosis (CF) is a lethal genetic disease caused by mutations in the chloride ion channel cystic fibrosis transmembrane conductance regulator (CFTR). Class-II mutants of CFTR lack intermolecular interactions important for CFTR structural stability and lead to misfolding. Misfolded CFTR is detected by a diverse suite of proteostasis factors that preferentially bind and route mutant CFTR toward premature degradation, resulting in reduced plasma membrane CFTR levels and impaired chloride ion conductance associated with CF. CF treatment has been vastly improved over the past decade by the availability of small molecules called correctors. Correctors directly bind CFTR, stabilize its structure by conferring thermodynamically favorable interactions that compensate for mutations, and thereby lead to downstream folding fidelity. However, each of over 100 Class-II CF causing mutations causes unique structural defects and shows a unique response to drug treatment, described as theratype. Understanding CFTR structural defects, the proteostasis factors evaluating those defects, and the stabilizing effects of CFTR correctors will illuminate a path toward personalized medicine for CF. Here, we review recent advances in our understanding of CFTR folding, focusing on structure, corrector binding sites, the mechanisms of proteostasis factors that evaluate CFTR, and the implications for CF personalized medicine.
Collapse
Affiliation(s)
- Eli Fritz McDonald
- Department
of Chemistry, Vanderbilt University, Nashville, Tennessee 37235, United States
- Center
for Structural Biology, Vanderbilt University, Nashville, Tennessee 37240, United States
| | - Jens Meiler
- Department
of Chemistry, Vanderbilt University, Nashville, Tennessee 37235, United States
- Center
for Structural Biology, Vanderbilt University, Nashville, Tennessee 37240, United States
- Department
of Pharmacology, Vanderbilt University, Nashville, Tennessee 37240, United States
- Institute
for Drug Discovery, Leipzig University, Leipzig, SAC 04103, Germany
| | - Lars Plate
- Department
of Chemistry, Vanderbilt University, Nashville, Tennessee 37235, United States
- Department
of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37235, United States
- Department
of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
| |
Collapse
|
14
|
Qu C, Guan X, Li C, Zhu X, Ma T, Li H, Yu B, Yang H. Sesquiterpene lactones improve secretory diarrhea symptoms by inhibiting intestinal Ca 2+-activated Cl - channel activities directly and indirectly. Eur J Pharmacol 2023; 955:175917. [PMID: 37473982 DOI: 10.1016/j.ejphar.2023.175917] [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: 03/29/2023] [Revised: 07/15/2023] [Accepted: 07/17/2023] [Indexed: 07/22/2023]
Abstract
Secretory diarrhea caused by bacteria and viruses is usually accompanied by activation of the cystic fibrosis transmembrane conductance regulator (CFTR) and calcium-activated Cl- channels (CaCCs) in the intestinal epithelium. Inhibition of CFTR and CaCCs activities significantly reduces fluid losses and intestinal motility in diarrheal diseases. For this reason, CFTR and CaCCs are potential targets of therapeutic drug screening. Here, we reported that the sesquiterpene lactones, alantolactone (AL) and isoalantolactone (iAL), significantly inhibited ATP and Eact-induced short-circuit currents in T84, HT-29 and Fischer rat thyroid (FRT) cells expressing transmembrane protein 16A (TMEM16A) in a concentration-dependent manner. AL and iAL also inhibited the CaCC-mediated short-circuit currents induced by carbachol in the mouse colons. Both compounds inhibited forskolin-induced currents in T84 cells but did not significantly affect mouse colons. In vivo studies indicated that AL and iAL attenuated gastrointestinal motility and decreased watery diarrhea in rotavirus-infected neonatal mice. Preliminary mechanism studies showed that AL and iAL inhibited CaCCs at least partially by inhibiting Ca2+ release and basolateral membrane K+ channels activity. These findings suggest a new pharmacological activity of sesquiterpene lactone compounds that might lead to the development of treatments for rotaviral secretory diarrhea.
Collapse
Affiliation(s)
- Chao Qu
- Liaoning Provincial Key Laboratory of Biotechnology and Drug Discovery, School of Life Science, Liaoning Normal University, Dalian, China
| | - Xin Guan
- Liaoning Provincial Key Laboratory of Biotechnology and Drug Discovery, School of Life Science, Liaoning Normal University, Dalian, China; Stem Cell Clinical Research Center, National Joint Engineering Laboratory, The First Affiliated Hospital of Dalian Medical University, Dalian, China; Dalian Innovation Institute of Stem Cell and Precision Medicine, Dalian, China
| | - Chang Li
- Liaoning Provincial Key Laboratory of Biotechnology and Drug Discovery, School of Life Science, Liaoning Normal University, Dalian, China
| | - Xiaojuan Zhu
- Liaoning Provincial Key Laboratory of Biotechnology and Drug Discovery, School of Life Science, Liaoning Normal University, Dalian, China
| | - Tonghui Ma
- Liaoning Provincial Key Laboratory of Biotechnology and Drug Discovery, School of Life Science, Liaoning Normal University, Dalian, China
| | - Hongyan Li
- Liaoning Provincial Key Laboratory of Biotechnology and Drug Discovery, School of Life Science, Liaoning Normal University, Dalian, China.
| | - Bo Yu
- Liaoning Provincial Key Laboratory of Biotechnology and Drug Discovery, School of Life Science, Liaoning Normal University, Dalian, China.
| | - Hong Yang
- Liaoning Provincial Key Laboratory of Biotechnology and Drug Discovery, School of Life Science, Liaoning Normal University, Dalian, China.
| |
Collapse
|
15
|
Lai J, Zhuo X, Yin K, Jiang F, Liu L, Xu X, Liu H, Wang J, Zhao J, Xu W, Yang S, Guo H, Yuan X, Lin X, Qi F, Fu G. Potential mechanism of pyrotinib-induced diarrhea was explored by gut microbiome and ileum metabolomics. Anticancer Drugs 2023; 34:747-762. [PMID: 36378136 DOI: 10.1097/cad.0000000000001440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Pyrotinib is a novel epidermal growth factor receptor/human epidermal growth factor receptor-2 (HER2) tyrosine kinase inhibitor that exhibited clinical efficacy in patients with HER2-positive breast cancer and HER2-mutant/amplified lung cancer. However, severe diarrhea adverse responses preclude its practical use. At present, the mechanism of pyrotinib-induced diarrhea is unknown and needs further study. First, to develop a suitable and reproducible animal model, we compared the effects of different doses of pyrotinib (20, 40, 60 and 80 mg/kg) in Wistar rats. Second, we used this model to examine the intestinal toxicity of pyrotinib. Finally, the mechanism underlying pyrotinib-induced diarrhea was fully studied using gut microbiome and host intestinal tissue metabolomics profiling. Reproducible diarrhea occurred in rats when they were given an 80 mg/kg daily dose of pyrotinib. Using the pyrotinib-induced model, we observed that Lachnospiraceae and Acidaminococcaceae decreased in the pyrotinib groups, whereas Enterobacteriaceae, Helicobacteraceae and Clostridiaceae increased at the family level by 16S rRNA gene sequence. Multiple bioinformatics methods revealed that glycocholic acid, ursodeoxycholic acid and cyclic AMP increased in the pyrotinib groups, whereas kynurenic acid decreased, which may be related to the pathogenesis of pyrotinib-induced diarrhea. Additionally, pyrotinib-induced diarrhea may be associated with a number of metabolic changes mediated by the gut microbiome, such as Primary bile acid biosynthesis. We reported the establishment of a reproducible pyrotinib-induced animal model for the first time. Furthermore, we concluded from this experiment that gut microbiome imbalance and changes in related metabolites are significant contributors to pyrotinib-induced diarrhea.
Collapse
Affiliation(s)
- Jingjiang Lai
- Department of Oncology, Shandong Provincial Hospital Affiliated to Shandong First Medical University
- The Second Clinical Medical College, Shandong University of Traditional Chinese Medicine
| | - Xiaoli Zhuo
- Department of Oncology, Shandong Provincial Hospital Affiliated to Shandong First Medical University
- The Clinical Medical College, Shandong First Medical University (Shandong Academy of Medicine)
| | - Ke Yin
- Department of Pathology, Shandong Provincial Hospital, Cheeloo College of Medicine
| | - Fengxian Jiang
- Department of Oncology, Shandong Provincial Hospital Affiliated to Shandong First Medical University
- The Second Clinical Medical College, Shandong University of Traditional Chinese Medicine
| | - Lei Liu
- Department of Oncology, Shandong Provincial Hospital Affiliated to Shandong First Medical University
- The Clinical Medical College, Shandong First Medical University (Shandong Academy of Medicine)
| | - Xiaoying Xu
- Department of Pathology, Shandong Provincial Hospital, Cheeloo College of Medicine
| | - Hongjing Liu
- The Second Clinical Medical College, Shandong University of Traditional Chinese Medicine
| | - Jingliang Wang
- Department of Oncology, Shandong Provincial Hospital Affiliated to Shandong First Medical University
- The Second Clinical Medical College, Shandong University of Traditional Chinese Medicine
| | - Jing Zhao
- Department of Oncology, Shandong Provincial Hospital Affiliated to Shandong First Medical University
- The Clinical Medical College, Shandong First Medical University (Shandong Academy of Medicine)
| | | | - Shuping Yang
- Department of Oncology, Shandong Provincial Hospital Affiliated to Shandong First Medical University
| | - Honglin Guo
- Department of Central Laboratory, Shandong Provincial Hospital
- Department of Biostatistics, School of Public Health, Cheeloo College of Medicine, Shandong University
| | | | - Xiaoyan Lin
- Department of Pathology, Shandong Provincial Hospital, Cheeloo College of Medicine
- Department of Pathology
| | - Fanghua Qi
- Traditional Chinese Medicine, Shandong Provincial Hospital affiliated to Shandong First Medical University, Jinan, China
| | - Guobin Fu
- Department of Oncology, Shandong Provincial Hospital Affiliated to Shandong First Medical University
- Department of Oncology
| |
Collapse
|
16
|
Levring J, Terry DS, Kilic Z, Fitzgerald G, Blanchard SC, Chen J. CFTR function, pathology and pharmacology at single-molecule resolution. Nature 2023; 616:606-614. [PMID: 36949202 PMCID: PMC10115640 DOI: 10.1038/s41586-023-05854-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 02/16/2023] [Indexed: 03/24/2023]
Abstract
The cystic fibrosis transmembrane conductance regulator (CFTR) is an anion channel that regulates salt and fluid homeostasis across epithelial membranes1. Alterations in CFTR cause cystic fibrosis, a fatal disease without a cure2,3. Electrophysiological properties of CFTR have been analysed for decades4-6. The structure of CFTR, determined in two globally distinct conformations, underscores its evolutionary relationship with other ATP-binding cassette transporters. However, direct correlations between the essential functions of CFTR and extant structures are lacking at present. Here we combine ensemble functional measurements, single-molecule fluorescence resonance energy transfer, electrophysiology and kinetic simulations to show that the two nucleotide-binding domains (NBDs) of human CFTR dimerize before channel opening. CFTR exhibits an allosteric gating mechanism in which conformational changes within the NBD-dimerized channel, governed by ATP hydrolysis, regulate chloride conductance. The potentiators ivacaftor and GLPG1837 enhance channel activity by increasing pore opening while NBDs are dimerized. Disease-causing substitutions proximal (G551D) or distal (L927P) to the ATPase site both reduce the efficiency of NBD dimerization. These findings collectively enable the framing of a gating mechanism that informs on the search for more efficacious clinical therapies.
Collapse
Affiliation(s)
- Jesper Levring
- Laboratory of Membrane Biology and Biophysics, The Rockefeller University, New York, NY, USA
| | - Daniel S Terry
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Zeliha Kilic
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Gabriel Fitzgerald
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY, USA
| | - Scott C Blanchard
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, USA.
| | - Jue Chen
- Laboratory of Membrane Biology and Biophysics, The Rockefeller University, New York, NY, USA.
- Howard Hughes Medical Institute, The Rockefeller University, New York, NY, USA.
| |
Collapse
|
17
|
Hwang TC, Braakman I, van der Sluijs P, Callebaut I. Structure basis of CFTR folding, function and pharmacology. J Cyst Fibros 2023; 22 Suppl 1:S5-S11. [PMID: 36216744 DOI: 10.1016/j.jcf.2022.09.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 09/19/2022] [Accepted: 09/26/2022] [Indexed: 11/05/2022]
Abstract
The root cause of cystic fibrosis (CF), the most common life-shortening genetic disease in the Caucasian population, is the loss of function of the CFTR protein, which serves as a phosphorylation-activated, ATP-gated anion channel in numerous epithelia-lining tissues. In the past decade, high-throughput drug screening has made a significant stride in developing highly effective CFTR modulators for the treatment of CF. Meanwhile, structural-biology studies have succeeded in solving the high-resolution three-dimensional (3D) structure of CFTR in different conformations. Here, we provide a brief overview of some striking features of CFTR folding, function and pharmacology, in light of its specific structural features within the ABC-transporter superfamily. A particular focus is given to CFTR's first nucleotide-binding domain (NBD1), because folding of NBD1 constitutes a bottleneck in the CFTR protein biogenesis pathway, and ATP binding to this domain plays a unique role in the functional stability of CFTR. Unraveling the molecular basis of CFTR folding, function, and pharmacology would inspire the development of next-generation mutation-specific CFTR modulators.
Collapse
Affiliation(s)
- Tzyh-Chang Hwang
- Institute of Pharmacology, School of Medicine, National Yang Ming Chiao Tung University, Taiwan; Department of Medical Pharmacology and Physiology, Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO, USA
| | - Ineke Braakman
- Cellular Protein Chemistry, Bijvoet Centre for Biomolecular Research, Utrecht University, 3584 CH Utrecht, The Netherlands
| | - Peter van der Sluijs
- Cellular Protein Chemistry, Bijvoet Centre for Biomolecular Research, Utrecht University, 3584 CH Utrecht, The Netherlands
| | - Isabelle Callebaut
- Sorbonne Université, Muséum National d'Histoire Naturelle, UMR CNRS 7590, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, IMPMC, 75005 Paris, France.
| |
Collapse
|
18
|
Zeng ZW, Linsdell P, Pomès R. Molecular dynamics study of Cl - permeation through cystic fibrosis transmembrane conductance regulator (CFTR). Cell Mol Life Sci 2023; 80:51. [PMID: 36694009 PMCID: PMC9873711 DOI: 10.1007/s00018-022-04621-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Revised: 10/26/2022] [Accepted: 10/31/2022] [Indexed: 01/25/2023]
Abstract
The recent elucidation of atomistic structures of Cl- channel CFTR provides opportunities for understanding the molecular basis of cystic fibrosis. Despite having been activated through phosphorylation and provided with ATP ligands, several near-atomistic cryo-EM structures of CFTR are in a closed state, as inferred from the lack of a continuous passage through a hydrophobic bottleneck region located in the extracellular portion of the pore. Here, we present repeated, microsecond-long molecular dynamics simulations of human CFTR solvated in a lipid bilayer and aqueous NaCl. At equilibrium, Cl- ions enter the channel through a lateral intracellular portal and bind to two distinct cationic sites inside the channel pore but do not traverse the narrow, de-wetted bottleneck. Simulations conducted in the presence of a strong hyperpolarizing electric field led to spontaneous Cl- translocation events through the bottleneck region of the channel, suggesting that the protein relaxed to a functionally open state. Conformational changes of small magnitude involving transmembrane helices 1 and 6 preceded ion permeation through diverging exit routes at the extracellular end of the pore. The pore bottleneck undergoes wetting prior to Cl- translocation, suggesting that it acts as a hydrophobic gate. Although permeating Cl- ions remain mostly hydrated, partial dehydration occurs at the binding sites and in the bottleneck. The observed Cl- pathway is largely consistent with the loci of mutations that alter channel conductance, anion binding, and ion selectivity, supporting the model of the open state of CFTR obtained in the present study.
Collapse
Affiliation(s)
- Zhi Wei Zeng
- Molecular Medicine, Hospital for Sick Children, 686 Bay Street, Toronto, ON, M5G 0A4, Canada
- Department of Biochemistry, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Paul Linsdell
- Department of Physiology and Biophysics, Dalhousie University, PO Box 15000, Halifax, NS, B3H 1X5, Canada
| | - Régis Pomès
- Molecular Medicine, Hospital for Sick Children, 686 Bay Street, Toronto, ON, M5G 0A4, Canada.
- Department of Biochemistry, University of Toronto, Toronto, ON, M5S 1A8, Canada.
| |
Collapse
|
19
|
Lai J, Jiang F, Zhuo X, Xu X, Liu L, Yin K, Wang J, Zhao J, Xu W, Liu H, Wang X, Jiang W, Wang K, Yang S, Guo H, Qi F, Yuan X, Lin X, Fu G. Effects of Shenling Baizhu powder on pyrotinib-induced diarrhea: analysis of gut microbiota, metabonomics, and network pharmacology. Chin Med 2022; 17:140. [PMID: 36528679 PMCID: PMC9759852 DOI: 10.1186/s13020-022-00696-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 12/05/2022] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Shenling Baizhu Powder (SBP) is a traditional Chinese medicine (TCM) prescription, which has the good efficacy on gastrointestinal toxicity. In this study, we used gut microbiota analysis, metabonomics and network pharmacology to investigate the therapeutic effect of SBP on pyrotinib-induced diarrhea. METHODS 24 Rats were randomly divided into 4 groups: control group, SBP group (3.6 g/kg /bid SBP for 10 days), pyrotinib model group (80 mg/kg/qd pyrotinib) and pyrotinib + SBP treatment group. A 16S rRNA sequencing was used to detect the microbiome of rat fecal bowel. Metabolic profiles were collected by non-targeted metabolomics and key metabolic pathways were identified using MetaboAnalyst 5.0. The antitumor effect of SBP on cells treated with pyrotinib was measured using a CCK-8 assay. Network pharmacology was used to predict the target and action pathway of SBP in treating pyrotinib-related diarrhea. RESULTS In vivo study indicated that SBP could significantly alleviate pyrotinib-induced diarrhea, reaching a therapeutic effect of 66.7%. SBP could regulate pyrotinib-induced microbiota disorder. LEfSe research revealed that the SBP could potentially decrease the relative abundance of Escherichia, Helicobacter and Enterobacteriaceae and increase the relative abundance of Lachnospiraceae, Bacilli, Lactobacillales etc. In addition, 25-Hydroxycholesterol, Guanidinosuccinic acid, 5-Hydroxyindolepyruvate and cAMP were selected as potential biomarkers of SBP for pyrotinib-induced diarrhea. Moreover, Spearman's analysis showed a correlation between gut microbiota and metabolite: the decreased 25-hydroxycholesterol in the pyrotinib + SBP treatment group was negatively correlated with Lachnospiraceae while positively correlated with Escherichia and Helicobacter. Meanwhile, SBP did not affect the inhibitory effect of pyrotinib on BT-474 cells and Calu-3 cells in vitro. Also, the network analysis further revealed that SBP treated pyrotinib-induced diarrhea through multiple pathways, including inflammatory bowel disease, IL-17 signaling pathway, pathogenic Escherichia coli infection and cAMP signaling pathway. CONCLUSIONS SBP could effectively relieve pyrotinib-induced diarrhea, revealing that intestinal flora and its metabolites may be involved in this process.
Collapse
Affiliation(s)
- Jingjiang Lai
- grid.460018.b0000 0004 1769 9639Department of Oncology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, 250021 People’s Republic of China ,grid.464402.00000 0000 9459 9325The Second Clinical Medical College, Shandong University of Traditional Chinese Medicine, Jinan, 250002 People’s Republic of China
| | - Fengxian Jiang
- grid.460018.b0000 0004 1769 9639Department of Oncology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, 250021 People’s Republic of China ,grid.464402.00000 0000 9459 9325The Second Clinical Medical College, Shandong University of Traditional Chinese Medicine, Jinan, 250002 People’s Republic of China
| | - Xiaoli Zhuo
- grid.460018.b0000 0004 1769 9639Department of Oncology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, 250021 People’s Republic of China ,grid.410638.80000 0000 8910 6733The Clinical Medical College, Shandong First Medical University (Shandong Academy of Medicine), Jinan, 250117 People’s Republic of China
| | - Xiaoying Xu
- grid.27255.370000 0004 1761 1174Department of Pathology, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, 250021 People’s Republic of China
| | - Lei Liu
- grid.460018.b0000 0004 1769 9639Department of Oncology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, 250021 People’s Republic of China ,grid.410638.80000 0000 8910 6733The Clinical Medical College, Shandong First Medical University (Shandong Academy of Medicine), Jinan, 250117 People’s Republic of China
| | - Ke Yin
- grid.27255.370000 0004 1761 1174Department of Pathology, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, 250021 People’s Republic of China
| | - Jingliang Wang
- grid.460018.b0000 0004 1769 9639Department of Oncology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, 250021 People’s Republic of China ,grid.464402.00000 0000 9459 9325The Second Clinical Medical College, Shandong University of Traditional Chinese Medicine, Jinan, 250002 People’s Republic of China
| | - Jing Zhao
- grid.460018.b0000 0004 1769 9639Department of Oncology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, 250021 People’s Republic of China ,grid.410638.80000 0000 8910 6733The Clinical Medical College, Shandong First Medical University (Shandong Academy of Medicine), Jinan, 250117 People’s Republic of China
| | - Wei Xu
- grid.27255.370000 0004 1761 1174Department of Oncology, Shandong Provincial Hospital Cheeloo College of Medicine, Shandong University, Jinan, 250021 People’s Republic of China
| | - Hongjing Liu
- grid.464402.00000 0000 9459 9325The Second Clinical Medical College, Shandong University of Traditional Chinese Medicine, Jinan, 250002 People’s Republic of China
| | - Xuan Wang
- grid.464402.00000 0000 9459 9325The Second Clinical Medical College, Shandong University of Traditional Chinese Medicine, Jinan, 250002 People’s Republic of China
| | - Wen Jiang
- grid.460018.b0000 0004 1769 9639Traditional Chinese Medicine, Shandong Provincial Hospital affiliated to Shandong First Medical University, Jinan, China
| | - Ke Wang
- grid.460018.b0000 0004 1769 9639Traditional Chinese Medicine, Shandong Provincial Hospital affiliated to Shandong First Medical University, Jinan, China
| | - Shuping Yang
- grid.460018.b0000 0004 1769 9639Department of Oncology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, 250021 People’s Republic of China
| | - Honglin Guo
- grid.27255.370000 0004 1761 1174Department of Central Laboratory, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, 250021 People’s Republic of China ,grid.27255.370000 0004 1761 1174Department of Biostatistics, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, 250021 People’s Republic of China
| | - Fanghua Qi
- grid.460018.b0000 0004 1769 9639Traditional Chinese Medicine, Shandong Provincial Hospital affiliated to Shandong First Medical University, Jinan, China
| | - Xiaotian Yuan
- grid.460018.b0000 0004 1769 9639Laboratory Animal Center, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, 250021 People’s Republic of China
| | - Xiaoyan Lin
- grid.27255.370000 0004 1761 1174Department of Pathology, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, 250021 People’s Republic of China ,grid.460018.b0000 0004 1769 9639Department of Pathology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, 250021 People’s Republic of China
| | - Guobin Fu
- grid.460018.b0000 0004 1769 9639Department of Oncology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, 250021 People’s Republic of China ,grid.27255.370000 0004 1761 1174Department of Oncology, Shandong Provincial Hospital Cheeloo College of Medicine, Shandong University, Jinan, 250021 People’s Republic of China
| |
Collapse
|
20
|
Tomati V, Costa S, Capurro V, Pesce E, Pastorino C, Lena M, Sondo E, Di Duca M, Cresta F, Cristadoro S, Zara F, Galietta LJ, Bocciardi R, Castellani C, Lucanto MC, Pedemonte N. Rescue by elexacaftor-tezacaftor-ivacaftor of the G1244E cystic fibrosis mutation's stability and gating defects are dependent on cell background. J Cyst Fibros 2022:S1569-1993(22)01425-4. [DOI: 10.1016/j.jcf.2022.12.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Revised: 11/23/2022] [Accepted: 12/13/2022] [Indexed: 12/23/2022]
|
21
|
Tripathy P, Biswas S. Mechanical and thermal properties of mineral fiber based polymeric nanocomposites: a review. POLYM-PLAST TECH MAT 2022. [DOI: 10.1080/25740881.2022.2061996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2023]
Affiliation(s)
- Priyanka Tripathy
- Department of Mechanical Engineering, National Institute of Technology, Rourkela, 769008 India
| | - Sandhyarani Biswas
- Department of Mechanical Engineering, National Institute of Technology, Rourkela, 769008 India
| |
Collapse
|
22
|
Cuyx S, Ramalho SS, Callebaut I, Cuppens H, Kmit A, Arnauts K, Ferrante M, Verfaillie C, Ensinck M, Carlon MS, Boon M, Proesmans M, Dupont L, De Boeck K, Farinha CM, Vermeulen F, Ramalho AS. Severity of the S1251N allele in cystic fibrosis is affected by the presence of the F508C variant in cis. J Cyst Fibros 2022; 21:644-651. [PMID: 35690578 DOI: 10.1016/j.jcf.2022.05.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2022] [Revised: 04/25/2022] [Accepted: 05/30/2022] [Indexed: 11/16/2022]
Abstract
BACKGROUND In cystic fibrosis (CF), genotype-phenotype correlation is complicated by the large number of CFTR variants, the influence of modifier genes, environmental effects, and the existence of complex alleles. We document the importance of complex alleles, in particular the F508C variant present in cis with the S1251N disease-causing variant, by detailed analysis of a patient with CF, with the [S1251N;F508]/G542X genotype and a very mild phenotype, contrasting it to that of four subjects with the [S1251N;F508C]/F508del genotype and classical CF presentation. METHODS Genetic differences were identified by Sanger sequencing and CFTR function was quantified using rectal organoids in rectal organoid morphology analysis (ROMA) and forskolin-induced swelling (FIS) assays. CFTR variants were further characterised in CF bronchial epithelial (CFBE) cell lines. The impact of involved amino acid changes in the CFTR 3D protein structure was evaluated. RESULTS Organoids of the patient [S1251N;F508] with mild CF phenotype confirmed the CF diagnosis but showed higher residual CFTR function compared to the four others [S1251N;F508C]. CFBE cell lines showed a decrease in [S1251N;F508C]-CFTR function but not in processing when compared to [S1251N;F508]-CFTR. Analysis of the 3D CFTR structure suggested an additive deleterious effect of the combined presence of S1251N and F508C with respect to NBD1-2 dimerisation. CONCLUSIONS In vitro and in silico data show that the presence of F508C in cis with S1251N decreases CFTR function without affecting processing. Complex CFTR alleles play a role in clinical phenotype and their identification is relevant in the context of personalised medicine for each patient with CF.
Collapse
Affiliation(s)
- Senne Cuyx
- KU Leuven, Department of Development and Regeneration, Woman and Child Unit, CF research lab, B-3000 Leuven, Belgium; University Hospital Leuven, Department of Pediatrics, Pediatric Pulmonology, B-3000 Leuven, Belgium
| | - Sofia S Ramalho
- University of Lisboa, BioISI - Biosystems & Integrative Sciences Institute, Faculty of Sciences, Campo Grande, C8 bdg, 1749-016 Lisboa, Portugal
| | - Isabelle Callebaut
- Sorbonne Université, Muséum National d'Histoire Naturelle, UMR CNRS 7590, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, IMPMC, F-75005 Paris, France
| | | | - Arthur Kmit
- University of Lisboa, BioISI - Biosystems & Integrative Sciences Institute, Faculty of Sciences, Campo Grande, C8 bdg, 1749-016 Lisboa, Portugal
| | - Kaline Arnauts
- Department of Chronic Diseases, Metabolism and Ageing (CHROMETA), Translational Research Center for Gastrointestinal Disorders (TARGID), KU Leuven, Leuven, Belgium; KU Leuven, Department of Development and Regeneration, Stem Cell Institute Leuven (SCIL), B-3000 Leuven, Belgium
| | - Marc Ferrante
- Department of Chronic Diseases, Metabolism and Ageing (CHROMETA), Translational Research Center for Gastrointestinal Disorders (TARGID), KU Leuven, Leuven, Belgium; KU Leuven, Department of Gastroenterology and Hepatology, University Hospital Leuven, B-3000 Leuven, Belgium
| | - Catherine Verfaillie
- KU Leuven, Department of Development and Regeneration, Stem Cell Institute Leuven (SCIL), B-3000 Leuven, Belgium
| | - Marjolein Ensinck
- Laboratory for Molecular Virology and Drug Discovery, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, 3000, Belgium; KU Leuven, Department of Chronic Diseases, Metabolism and Ageing; BREATHE, B-3000 Leuven, Belgium
| | - Marianne S Carlon
- Laboratory for Molecular Virology and Drug Discovery, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, 3000, Belgium; KU Leuven, Department of Chronic Diseases, Metabolism and Ageing; BREATHE, B-3000 Leuven, Belgium
| | - Mieke Boon
- KU Leuven, Department of Development and Regeneration, Woman and Child Unit, CF research lab, B-3000 Leuven, Belgium; University Hospital Leuven, Department of Pediatrics, Pediatric Pulmonology, B-3000 Leuven, Belgium
| | - Marijke Proesmans
- KU Leuven, Department of Development and Regeneration, Woman and Child Unit, CF research lab, B-3000 Leuven, Belgium; University Hospital Leuven, Department of Pediatrics, Pediatric Pulmonology, B-3000 Leuven, Belgium
| | - Lieven Dupont
- KU Leuven, Department of Chronic Diseases, Metabolism and Ageing; BREATHE, B-3000 Leuven, Belgium; University Hospital Leuven, Department of Respiratory Diseases, B-3000 Leuven, Belgium
| | - Kris De Boeck
- KU Leuven, Department of Development and Regeneration, Woman and Child Unit, CF research lab, B-3000 Leuven, Belgium; University Hospital Leuven, Department of Pediatrics, Pediatric Pulmonology, B-3000 Leuven, Belgium
| | - Carlos M Farinha
- University of Lisboa, BioISI - Biosystems & Integrative Sciences Institute, Faculty of Sciences, Campo Grande, C8 bdg, 1749-016 Lisboa, Portugal
| | - François Vermeulen
- KU Leuven, Department of Development and Regeneration, Woman and Child Unit, CF research lab, B-3000 Leuven, Belgium; University Hospital Leuven, Department of Pediatrics, Pediatric Pulmonology, B-3000 Leuven, Belgium
| | - Anabela S Ramalho
- KU Leuven, Department of Development and Regeneration, Woman and Child Unit, CF research lab, B-3000 Leuven, Belgium
| |
Collapse
|
23
|
Fang X, Yeh JT, Hwang TC. Pharmacological Responses of the G542X-CFTR to CFTR Modulators. Front Mol Biosci 2022; 9:921680. [PMID: 35813815 PMCID: PMC9263564 DOI: 10.3389/fmolb.2022.921680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2022] [Accepted: 05/16/2022] [Indexed: 11/13/2022] Open
Abstract
Cystic fibrosis (CF) is a lethal hereditary disease caused by loss-of-function mutations of the chloride channel cystic fibrosis transmembrane conductance regulator (CFTR). With the development of small-molecule CFTR modulators, including correctors that facilitate protein folding and expression and potentiators that promote channel activity, about 90% of the CF patients are now receiving efficacious target therapies. G542X-CFTR, a premature termination codon (PTC) mutation, is the most common disease-associated mutation found in the remaining 10% of patients that await effective drugs to rectify the fundamental defects caused by PTC. In this study, we employed biophysical and biochemical techniques to characterize the pharmacological responses of the translational products of G542X-CFTR to a range of new CFTR modulators. Specifically, we identified two different proteins translated from the G542X-CFTR cDNA using western blotting: the C-terminus truncated protein that responds to the C1 corrector which binds to the N-terminal part of the protein and a full-length CFTR protein through the read-through process. Electrophysiological data suggest that the read-through protein, but not the C-terminus truncated one, is functional and responds well to CFTR potentiators despite a lower open probability compared to wild-type CFTR. As the expression of the read-through products can be increased synergistically with the read-through reagent G418 and C1 corrector, but not with combinations of different types of correctors, we concluded that an efficacious read-through reagent is a prerequisite for mitigating the deficits of G542X-CFTR. Moreover, the CFTR potentiators may help improve the effectiveness of future combinational therapy for patients carrying PTCs such as G542X.
Collapse
Affiliation(s)
- Xinxiu Fang
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO, United States
| | - Jiunn-Tyng Yeh
- School of Medicine, National Yang Ming Chiao Tung University College of Medicine, Taipei, Taiwan
- *Correspondence: Jiunn-Tyng Yeh,
| | - Tzyh-Chang Hwang
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO, United States
- Department of Pharmacology, National Yang Ming Chiao Tung University College of Medicine, Taipei, Taiwan
| |
Collapse
|
24
|
Molecular mechanisms of Cystic Fibrosis - how mutations lead to misfunction and guide therapy. Biosci Rep 2022; 42:231430. [PMID: 35707985 PMCID: PMC9251585 DOI: 10.1042/bsr20212006] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 06/03/2022] [Accepted: 06/13/2022] [Indexed: 11/17/2022] Open
Abstract
Cystic fibrosis, the most common autosomal recessive disorder in Caucasians, is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, which encodes a cAMP-activated chloride and bicarbonate channel that regulates ion and water transport in secretory epithelia. Although all mutations lead to the lack or reduction in channel function, the mechanisms through which this occurs are diverse – ranging from lack of full-length mRNA, reduced mRNA levels, impaired folding and trafficking, targeting to degradation, decreased gating or conductance, and reduced protein levels to decreased half-life at the plasma membrane. Here, we review the different molecular mechanisms that cause cystic fibrosis and detail how these differences identify theratypes that can inform the use of directed therapies aiming at correcting the basic defect. In summary, we travel through CFTR life cycle from the gene to function, identifying what can go wrong and what can be targeted in terms of the different types of therapeutic approaches.
Collapse
|
25
|
Ensinck MM, Carlon MS. One Size Does Not Fit All: The Past, Present and Future of Cystic Fibrosis Causal Therapies. Cells 2022; 11:cells11121868. [PMID: 35740997 PMCID: PMC9220995 DOI: 10.3390/cells11121868] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 05/25/2022] [Accepted: 05/28/2022] [Indexed: 02/04/2023] Open
Abstract
Cystic fibrosis (CF) is the most common monogenic disorder, caused by mutations in the CF transmembrane conductance regulator (CFTR) gene. Over the last 30 years, tremendous progress has been made in understanding the molecular basis of CF and the development of treatments that target the underlying defects in CF. Currently, a highly effective CFTR modulator treatment (Kalydeco™/Trikafta™) is available for 90% of people with CF. In this review, we will give an extensive overview of past and ongoing efforts in the development of therapies targeting the molecular defects in CF. We will discuss strategies targeting the CFTR protein (i.e., CFTR modulators such as correctors and potentiators), its cellular environment (i.e., proteostasis modulation, stabilization at the plasma membrane), the CFTR mRNA (i.e., amplifiers, nonsense mediated mRNA decay suppressors, translational readthrough inducing drugs) or the CFTR gene (gene therapies). Finally, we will focus on how these efforts can be applied to the 15% of people with CF for whom no causal therapy is available yet.
Collapse
Affiliation(s)
- Marjolein M. Ensinck
- Molecular Virology and Gene Therapy, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, 3000 Leuven, Flanders, Belgium;
| | - Marianne S. Carlon
- Molecular Virology and Gene Therapy, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, 3000 Leuven, Flanders, Belgium;
- Laboratory of Respiratory Diseases and Thoracic Surgery (BREATHE), Department of Chronic Diseases and Metabolism, KU Leuven, 3000 Leuven, Flanders, Belgium
- Correspondence:
| |
Collapse
|
26
|
McDonald EF, Woods H, Smith ST, Kim M, Schoeder CT, Plate L, Meiler J. Structural Comparative Modeling of Multi-Domain F508del CFTR. Biomolecules 2022; 12:biom12030471. [PMID: 35327663 PMCID: PMC8946492 DOI: 10.3390/biom12030471] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 03/15/2022] [Accepted: 03/17/2022] [Indexed: 12/07/2022] Open
Abstract
Cystic fibrosis (CF) is a rare genetic disease caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR), an epithelial anion channel expressed in several vital organs. Absence of functional CFTR results in imbalanced osmotic equilibrium and subsequent mucus build up in the lungs-which increases the risk of infection and eventually causes death. CFTR is an ATP-binding cassette (ABC) transporter family protein composed of two transmembrane domains (TMDs), two nucleotide binding domains (NBDs), and an unstructured regulatory domain. The most prevalent patient mutation is the deletion of F508 (F508del), making F508del CFTR the primary target for current FDA approved CF therapies. However, no experimental multi-domain F508del CFTR structure has been determined and few studies have modeled F508del using multi-domain WT CFTR structures. Here, we used cryo-EM density data and Rosetta comparative modeling (RosettaCM) to compare a F508del model with published experimental data on CFTR NBD1 thermodynamics. We then apply this modeling method to generate multi-domain WT and F508del CFTR structural models. These models demonstrate the destabilizing effects of F508del on NBD1 and the NBD1/TMD interface in both the inactive and active conformation of CFTR. Furthermore, we modeled F508del/R1070W and F508del bound to the CFTR corrector VX-809. Our models reveal the stabilizing effects of VX-809 on multi-domain models of F508del CFTR and pave the way for rational design of additional drugs that target F508del CFTR for treatment of CF.
Collapse
Affiliation(s)
- Eli Fritz McDonald
- Department of Chemistry, Vanderbilt University, Nashville, TN 37235, USA; (E.F.M.); (C.T.S.); (L.P.)
- Center for Structural Biology, Vanderbilt University, Nashville, TN 37235, USA; (H.W.); (S.T.S.)
| | - Hope Woods
- Center for Structural Biology, Vanderbilt University, Nashville, TN 37235, USA; (H.W.); (S.T.S.)
- Program in Chemical and Physical Biology, Vanderbilt University, Nashville, TN 37235, USA;
| | - Shannon T. Smith
- Center for Structural Biology, Vanderbilt University, Nashville, TN 37235, USA; (H.W.); (S.T.S.)
- Program in Chemical and Physical Biology, Vanderbilt University, Nashville, TN 37235, USA;
| | - Minsoo Kim
- Program in Chemical and Physical Biology, Vanderbilt University, Nashville, TN 37235, USA;
| | - Clara T. Schoeder
- Department of Chemistry, Vanderbilt University, Nashville, TN 37235, USA; (E.F.M.); (C.T.S.); (L.P.)
- Center for Structural Biology, Vanderbilt University, Nashville, TN 37235, USA; (H.W.); (S.T.S.)
- Leipzig Medical School, Leipzig University, 04109 Leipzig, Germany
| | - Lars Plate
- Department of Chemistry, Vanderbilt University, Nashville, TN 37235, USA; (E.F.M.); (C.T.S.); (L.P.)
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235, USA
| | - Jens Meiler
- Department of Chemistry, Vanderbilt University, Nashville, TN 37235, USA; (E.F.M.); (C.T.S.); (L.P.)
- Center for Structural Biology, Vanderbilt University, Nashville, TN 37235, USA; (H.W.); (S.T.S.)
- Leipzig Medical School, Leipzig University, 04109 Leipzig, Germany
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37235, USA
- Institute for Drug Discovery, Leipzig University, 04109 Leipzig, Germany
- Correspondence: ; Tel.: +1-(615)-936-2211
| |
Collapse
|
27
|
Prins S, Corradi V, Sheppard DN, Tieleman DP, Vergani P. Can two wrongs make a right? F508del-CFTR ion channel rescue by second-site mutations in its transmembrane domains. J Biol Chem 2022; 298:101615. [PMID: 35065958 PMCID: PMC8861112 DOI: 10.1016/j.jbc.2022.101615] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 01/13/2022] [Accepted: 01/17/2022] [Indexed: 11/20/2022] Open
Abstract
Deletion of phenylalanine 508 (F508del) in the cystic fibrosis transmembrane conductance regulator (CFTR) anion channel is the most common cause of cystic fibrosis. The F508 residue is located on nucleotide-binding domain 1 (NBD1) in contact with the cytosolic extensions of the transmembrane helices, in particular intracellular loop 4 (ICL4). To investigate how absence of F508 at this interface impacts the CFTR protein, we carried out a mutagenesis scan of ICL4 by introducing second-site mutations at 11 positions in cis with F508del. Using an image-based fluorescence assay, we measured how each mutation affected membrane proximity and ion-channel function. The scan strongly validated the effectiveness of R1070W at rescuing F508del defects. Molecular dynamics simulations highlighted two features characterizing the ICL4/NBD1 interface of F508del/R1070W-CFTR: flexibility, with frequent transient formation of interdomain hydrogen bonds, and loosely stacked aromatic sidechains (F1068, R1070W, and F1074, mimicking F1068, F508, and F1074 in WT CFTR). F508del-CFTR displayed a distorted aromatic stack, with F1068 displaced toward the space vacated by F508, while in F508del/R1070F-CFTR, which largely retained F508del defects, R1070F could not form hydrogen bonds and the interface was less flexible. Other ICL4 second-site mutations which partially rescued F508del-CFTR included F1068M and F1074M. Methionine side chains allow hydrophobic interactions without the steric rigidity of aromatic rings, possibly conferring flexibility to accommodate the absence of F508 and retain a dynamic interface. These studies highlight how both hydrophobic interactions and conformational flexibility might be important at the ICL4/NBD1 interface, suggesting possible structural underpinnings of F508del-induced dysfunction.
Collapse
Affiliation(s)
- Stella Prins
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
| | - Valentina Corradi
- Department of Biological Sciences, Centre for Molecular Simulation, University of Calgary, Calgary, Alberta, Canada
| | - David N Sheppard
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK
| | - D Peter Tieleman
- Department of Biological Sciences, Centre for Molecular Simulation, University of Calgary, Calgary, Alberta, Canada
| | - Paola Vergani
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK.
| |
Collapse
|
28
|
Noel S, Servel N, Hatton A, Golec A, Rodrat M, Ng DRS, Li H, Pranke I, Hinzpeter A, Edelman A, Sheppard DN, Sermet-Gaudelus I. Correlating genotype with phenotype using CFTR-mediated whole-cell Cl - currents in human nasal epithelial cells. J Physiol 2021; 600:1515-1531. [PMID: 34761808 DOI: 10.1113/jp282143] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 11/01/2021] [Indexed: 12/20/2022] Open
Abstract
Dysfunction of the epithelial anion channel cystic fibrosis transmembrane conductance regulator (CFTR) causes a wide spectrum of disease, including cystic fibrosis (CF) and CFTR-related diseases (CFTR-RDs). Here, we investigate genotype-phenotype-CFTR function relationships using human nasal epithelial (hNE) cells from a small cohort of non-CF subjects and individuals with CF and CFTR-RDs and genotypes associated with either residual or minimal CFTR function using electrophysiological techniques. Collected hNE cells were either studied directly with the whole-cell patch-clamp technique or grown as primary cultures at an air-liquid interface after conditional reprogramming. The properties of cAMP-activated whole-cell Cl- currents in freshly isolated hNE cells identified them as CFTR-mediated. Their magnitude varied between hNE cells from individuals within the same genotype and decreased in the rank order: non-CF > CFTR residual function > CFTR minimal function. CFTR-mediated whole-cell Cl- currents in hNE cells isolated from fully differentiated primary cultures were identical to those in freshly isolated hNE cells in both magnitude and behaviour, demonstrating that conditional reprogramming culture is without effect on CFTR expression and function. For the cohort of subjects studied, CFTR-mediated whole-cell Cl- currents in hNE cells correlated well with CFTR-mediated transepithelial Cl- currents measured in vitro with the Ussing chamber technique, but not with those determined in vivo with the nasal potential difference assay. Nevertheless, they did correlate with the sweat Cl- concentration of study subjects. Thus, this study highlights the complexity of genotype-phenotype-CFTR function relationships, but emphasises the value of conditionally reprogrammed hNE cells in CFTR research and therapeutic testing. KEY POINTS: The genetic disease cystic fibrosis is caused by pathogenic variants in the cystic fibrosis transmembrane conductance regulator (CFTR), an ion channel, which controls anion flow across epithelia lining ducts and tubes in the body. This study investigated CFTR function in nasal epithelial cells from people with cystic fibrosis and CFTR variants with a range of disease severity. CFTR function varied widely in nasal epithelial cells depending on the identity of CFTR variants, but was unaffected by conditional reprogramming culture, a cell culture technique used to grow large numbers of patient-derived cells. Assessment of CFTR function in vitro in nasal epithelial cells and epithelia, and in vivo in the nasal epithelium and sweat gland highlights the complexity of genotype-phenotype-CFTR function relationships.
Collapse
Affiliation(s)
- Sabrina Noel
- INSERM U1151, Institut Necker-Enfants Malades, Paris, France.,Université de Paris, Paris, France
| | - Nathalie Servel
- INSERM U1151, Institut Necker-Enfants Malades, Paris, France.,Université de Paris, Paris, France
| | - Aurélie Hatton
- INSERM U1151, Institut Necker-Enfants Malades, Paris, France.,Université de Paris, Paris, France
| | - Anita Golec
- INSERM U1151, Institut Necker-Enfants Malades, Paris, France.,Université de Paris, Paris, France
| | - Mayuree Rodrat
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK.,Center of Research and Development for Biomedical Instrumentation, Institute of Molecular Biosciences, Mahidol University, Nakhon Pathom, Thailand
| | - Demi R S Ng
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK
| | - Hongyu Li
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK
| | - Iwona Pranke
- INSERM U1151, Institut Necker-Enfants Malades, Paris, France.,Université de Paris, Paris, France
| | - Alexandre Hinzpeter
- INSERM U1151, Institut Necker-Enfants Malades, Paris, France.,Université de Paris, Paris, France
| | - Aleksander Edelman
- INSERM U1151, Institut Necker-Enfants Malades, Paris, France.,Université de Paris, Paris, France
| | - David N Sheppard
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK
| | - Isabelle Sermet-Gaudelus
- INSERM U1151, Institut Necker-Enfants Malades, Paris, France.,Université de Paris, Paris, France.,Centre de Référence Maladies Rares, Mucoviscidose et Maladies Apparentées, Hôpital Necker-Enfants Malades, Paris, France.,European Reference Network on rare respiratory diseases, Frankfurt, Germany
| |
Collapse
|
29
|
Liu J, Berg AP, Wang Y, Jantarajit W, Sutcliffe KJ, Stevens EB, Cao L, Pregel MJ, Sheppard DN. A small molecule CFTR potentiator restores ATP-dependent channel gating to the cystic fibrosis mutant G551D-CFTR. Br J Pharmacol 2021; 179:1319-1337. [PMID: 34644413 PMCID: PMC9304199 DOI: 10.1111/bph.15709] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2021] [Accepted: 08/30/2021] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND AND PURPOSE Cystic fibrosis transmembrane conductance regulator (CFTR) potentiators are small molecules developed to treat the genetic disease cystic fibrosis (CF). They interact directly with CFTR Cl- channels at the plasma membrane to enhance channel gating. Here, we investigate the action of a new CFTR potentiator, CP-628006 with a distinct chemical structure. EXPERIMENTAL APPROACH Using electrophysiological assays with CFTR-expressing heterologous cells and CF patient-derived human bronchial epithelial (hBE) cells, we compared the effects of CP-628006 with the marketed CFTR potentiator ivacaftor. KEY RESULTS CP-628006 efficaciously potentiated CFTR function in epithelia from cultured hBE cells. Its effects on the predominant CFTR variant F508del-CFTR were larger than those with the gating variant G551D-CFTR. In excised inside-out membrane patches, CP-628006 potentiated wild-type, F508del- and G551D-CFTR by increasing the frequency and duration of channel openings. CP-628006 increased the affinity and efficacy of F508del-CFTR gating by ATP. In these respects, CP-628006 behaved like ivacaftor. CP-628006 also demonstrated notable differences with ivacaftor. Its potency and efficacy were lower than those of ivacaftor. CP-628006 conferred ATP-dependent gating on G551D-CFTR, whereas the action of ivacaftor was ATP-independent. For G551D-CFTR, but not F508del-CFTR, the action of CP-628006 plus ivacaftor was greater than ivacaftor alone. CP-628006 delayed, but did not prevent, the deactivation of F508del-CFTR at the plasma membrane, whereas ivacaftor accentuated F508del-CFTR deactivation. CONCLUSIONS AND IMPLICATIONS CP-628006 has distinct effects compared to ivacaftor, suggesting a different mechanism of CFTR potentiation. The emergence of CFTR potentiators with diverse modes of action makes therapy with combinations of potentiators a possibility.
Collapse
Affiliation(s)
- Jia Liu
- Neuroscience and Pain Research Unit, Pfizer Inc., Granta Park, Great Abington, Cambridge, UK.,School of Physiology, Pharmacology and Neuroscience, University of Bristol, Biomedical Sciences Building, University Walk, Bristol, UK
| | - Allison P Berg
- Rare Disease Research Unit, Pfizer Inc., Cambridge, MA, USA
| | - Yiting Wang
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Biomedical Sciences Building, University Walk, Bristol, UK
| | - Walailak Jantarajit
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Biomedical Sciences Building, University Walk, Bristol, UK.,Center of Calcium and Bone Research and Department of Physiology, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Katy J Sutcliffe
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Biomedical Sciences Building, University Walk, Bristol, UK
| | - Edward B Stevens
- Neuroscience and Pain Research Unit, Pfizer Inc., Granta Park, Great Abington, Cambridge, UK
| | - Lishuang Cao
- Neuroscience and Pain Research Unit, Pfizer Inc., Granta Park, Great Abington, Cambridge, UK
| | - Marko J Pregel
- Rare Disease Research Unit, Pfizer Inc., Cambridge, MA, USA
| | - David N Sheppard
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Biomedical Sciences Building, University Walk, Bristol, UK
| |
Collapse
|
30
|
Yeh HI, Yu YC, Kuo PL, Tsai CK, Huang HT, Hwang TC. Functional stability of CFTR depends on tight binding of ATP at its degenerate ATP-binding site. J Physiol 2021; 599:4625-4642. [PMID: 34411298 DOI: 10.1113/jp281933] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2021] [Accepted: 08/13/2021] [Indexed: 01/28/2023] Open
Abstract
Opening of the cystic fibrosis transmembrane conductance regulator (CFTR) channel is coupled to the motion of its two nucleotide-binding domains: they form a heterodimer sandwiching two functionally distinct ATP-binding sites (sites 1 and 2). While active ATP hydrolysis in site 2 triggers rapid channel closure, the functional role of stable ATP binding in the catalysis-incompetent (or degenerate) site 1, a feature conserved in many other ATP-binding cassette (ABC) transporter proteins, remains elusive. Here, we found that CFTR loses its prompt responsiveness to ATP after the channel is devoid of ATP for tens to hundreds of seconds. Mutants with weakened ATP binding in site 1 and the most prevalent disease-causing mutation, F508del, are more vulnerable to ATP depletion. In contrast, strengthening ligand binding in site 1 with N6 -(2-phenylethyl)-ATP, a high-affinity ATP analogue, or abolishing ATP hydrolysis in site 2 by the mutation D1370N, helps sustain a durable function of the otherwise unstable mutant channels. Thus, tight binding of ATP in the degenerate ATP-binding site is crucial to the functional stability of CFTR. Small molecules targeting site 1 may bear therapeutic potential to overcome the membrane instability of F508del-CFTR. KEY POINTS: During evolution, many ATP-binding cassette transporters - including the cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel, whose dysfunction causes cystic fibrosis (CF) - lose the ability to hydrolyse ATP in one of the two ATP-binding sites. Here we show that tight ATP binding at this degenerate site in CFTR is central for maintaining the stable, robust function of normal CFTR. We also demonstrate that membrane instability of the most common CF-causing mutant, F508del-CFTR, can be rescued by strengthening ATP binding at CFTR's degenerate site. Our data thus explain an evolutionary puzzle and offer a potential therapeutic strategy for CF.
Collapse
Affiliation(s)
- Han-I Yeh
- Dalton Cardiovascular Research Center and Department of Medical Pharmacology and Physiology, University of Missouri-Columbia, Columbia, MO, 65211, USA.,Department of Pharmacology, School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Ying-Chun Yu
- Dalton Cardiovascular Research Center and Department of Medical Pharmacology and Physiology, University of Missouri-Columbia, Columbia, MO, 65211, USA
| | - Pei-Lun Kuo
- School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Chun-Kuang Tsai
- School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Hsin-Tuan Huang
- School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Tzyh-Chang Hwang
- Dalton Cardiovascular Research Center and Department of Medical Pharmacology and Physiology, University of Missouri-Columbia, Columbia, MO, 65211, USA.,Department of Pharmacology, School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
| |
Collapse
|
31
|
Laselva O, Qureshi Z, Zeng ZW, Petrotchenko EV, Ramjeesingh M, Hamilton CM, Huan LJ, Borchers CH, Pomès R, Young R, Bear CE. Identification of binding sites for ivacaftor on the cystic fibrosis transmembrane conductance regulator. iScience 2021; 24:102542. [PMID: 34142049 PMCID: PMC8184517 DOI: 10.1016/j.isci.2021.102542] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 03/22/2021] [Accepted: 05/11/2021] [Indexed: 11/25/2022] Open
Abstract
Ivacaftor (VX-770) was the first cystic fibrosis transmembrane conductance regulator (CFTR) modulatory drug approved for the treatment of patients with cystic fibrosis. Electron cryomicroscopy (cryo-EM) studies of detergent-solubilized CFTR indicated that VX-770 bound to a site at the interface between solvent and a hinge region in the CFTR protein conferred by transmembrane (tm) helices: tm4, tm5, and tm8. We re-evaluated VX-770 binding to CFTR in biological membranes using photoactivatable VX-770 probes. One such probe covalently labeled CFTR at two sites as determined following trypsin digestion and analysis by tandem-mass spectrometry. One labeled peptide resides in the cytosolic loop 4 of CFTR and the other is located in tm8, proximal to the site identified by cryo-EM. Complementary data from functional and molecular dynamic simulation studies support a model, where VX-770 mediates potentiation via multiple sites in the CFTR protein.
Collapse
Affiliation(s)
- Onofrio Laselva
- Programme in Molecular Medicine, Hospital for Sick Children, 686 Bay Street, Toronto, ON M5G 0A4, Canada
- Department of Medical and Surgical Sciences, University of Foggia, Foggia, Italy
| | - Zafar Qureshi
- Department of Chemistry, Simon Fraser University, Burnaby, Canada
| | - Zhi-Wei Zeng
- Programme in Molecular Medicine, Hospital for Sick Children, 686 Bay Street, Toronto, ON M5G 0A4, Canada
- Department of Biochemistry, University of Toronto, Toronto, Canada
| | - Evgeniy V. Petrotchenko
- Segal Cancer Proteomics Center, Lady Davis Institute, Jewish General Hospital, McGill University, Montreal, Canada
- Center for Computational and Data-Intensive Science and Engineering, Skolkovo Institute of Science and Technology, Moscow 121205, Russia
| | - Mohabir Ramjeesingh
- Programme in Molecular Medicine, Hospital for Sick Children, 686 Bay Street, Toronto, ON M5G 0A4, Canada
| | | | - Ling-Jun Huan
- Programme in Molecular Medicine, Hospital for Sick Children, 686 Bay Street, Toronto, ON M5G 0A4, Canada
| | - Christoph H. Borchers
- Segal Cancer Proteomics Center, Lady Davis Institute, Jewish General Hospital, McGill University, Montreal, Canada
- Center for Computational and Data-Intensive Science and Engineering, Skolkovo Institute of Science and Technology, Moscow 121205, Russia
- Gerald Bronfman Department of Oncology, Jewish General Hospital, McGill University, Montreal, Quebec H3T 1E2, Canada
| | - Régis Pomès
- Programme in Molecular Medicine, Hospital for Sick Children, 686 Bay Street, Toronto, ON M5G 0A4, Canada
- Department of Biochemistry, University of Toronto, Toronto, Canada
| | - Robert Young
- Department of Chemistry, Simon Fraser University, Burnaby, Canada
| | - Christine E. Bear
- Programme in Molecular Medicine, Hospital for Sick Children, 686 Bay Street, Toronto, ON M5G 0A4, Canada
- Department of Physiology, University of Toronto, Toronto, Canada
- Department of Biochemistry, University of Toronto, Toronto, Canada
| |
Collapse
|
32
|
Della Sala A, Prono G, Hirsch E, Ghigo A. Role of Protein Kinase A-Mediated Phosphorylation in CFTR Channel Activity Regulation. Front Physiol 2021; 12:690247. [PMID: 34211404 PMCID: PMC8240754 DOI: 10.3389/fphys.2021.690247] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 05/10/2021] [Indexed: 11/17/2022] Open
Abstract
Cystic fibrosis transmembrane conductance regulator (CFTR) is an anion channel expressed on the apical membrane of epithelial cells, where it plays a pivotal role in chloride transport and overall tissue homeostasis. CFTR constitutes a unique member of the ATP-binding cassette transporter superfamily, due to its distinctive cytosolic regulatory (R) domain carrying multiple phosphorylation sites that allow the tight regulation of channel activity and gating. Mutations in the CFTR gene cause cystic fibrosis, the most common lethal autosomal genetic disease in the Caucasian population. In recent years, major efforts have led to the development of CFTR modulators, small molecules targeting the underlying genetic defect of CF and ultimately rescuing the function of the mutant channel. Recent evidence has highlighted that this class of drugs could also impact on the phosphorylation of the R domain of the channel by protein kinase A (PKA), a key regulatory mechanism that is altered in various CFTR mutants. Therefore, the aim of this review is to summarize the current knowledge on the regulation of the CFTR by PKA-mediated phosphorylation and to provide insights into the different factors that modulate this essential CFTR modification. Finally, the discussion will focus on the impact of CF mutations on PKA-mediated CFTR regulation, as well as on how small molecule CFTR regulators and PKA interact to rescue dysfunctional channels.
Collapse
Affiliation(s)
- Angela Della Sala
- Molecular Biotechnology Center, Department of Molecular Biotechnology and Health Sciences, University of Turin, Turin, Italy
| | | | - Emilio Hirsch
- Molecular Biotechnology Center, Department of Molecular Biotechnology and Health Sciences, University of Turin, Turin, Italy.,Kither Biotech S.r.l, Turin, Italy
| | - Alessandra Ghigo
- Molecular Biotechnology Center, Department of Molecular Biotechnology and Health Sciences, University of Turin, Turin, Italy.,Kither Biotech S.r.l, Turin, Italy
| |
Collapse
|
33
|
Linsdell P, Irving CL, Cowley EA, El Hiani Y. Two positively charged amino acid side-chains in the inner vestibule of the CFTR channel pore play analogous roles in controlling anion binding and anion conductance. Cell Mol Life Sci 2021; 78:5213-5223. [PMID: 34023918 PMCID: PMC11073087 DOI: 10.1007/s00018-021-03859-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 05/06/2021] [Accepted: 05/15/2021] [Indexed: 12/18/2022]
Abstract
Positively charged amino acid side-chains play important roles in anion binding and permeation through the CFTR chloride channel. One pore-lining lysine residue in particular (K95) has been shown to be indispensable for anion binding, conductance, and selectivity. Here, we use functional investigation of CFTR to show that a nearby arginine (R134) plays a functionally analogous role. Removal of this positive charge (in the R134Q mutant) drastically reduces single-channel conductance, weakens binding of both permeant and blocking anions, and abolishes the normal anion conductance selectivity pattern. Each of these functional effects was reversed by a second-site mutation (S1141K) that introduces an ectopic positive charge to a nearby pore-lining residue. Substituted cysteine accessibility experiments confirm that R134-but not nearby residues in the same transmembrane helix-is accessible within the pore lumen. These results suggest that K95 and R134, which are very close together within the inner vestibule of the pore, play analogous, important roles, and that both are required for the normal anion binding and anion conductance properties of the pore. Nevertheless, that fact that both positive charges can be "transplanted" to other sites in the inner vestibule with little effect on channel permeation properties indicates that it is the overall number of charges-rather than their exact locations-that controls pore function.
Collapse
Affiliation(s)
- Paul Linsdell
- Department of Physiology and Biophysics, Dalhousie University, PO Box 15000, Halifax, NS, B3H 4R2, Canada.
| | - Christina L Irving
- Department of Physiology and Biophysics, Dalhousie University, PO Box 15000, Halifax, NS, B3H 4R2, Canada
| | - Elizabeth A Cowley
- Department of Physiology and Biophysics, Dalhousie University, PO Box 15000, Halifax, NS, B3H 4R2, Canada
| | - Yassine El Hiani
- Department of Physiology and Biophysics, Dalhousie University, PO Box 15000, Halifax, NS, B3H 4R2, Canada
| |
Collapse
|
34
|
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.
Collapse
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
| |
Collapse
|
35
|
F1099L-CFTR (c.3297C>G) has Impaired Channel Function and Associates with Mild Disease Phenotypes in Two Pediatric Patients. Life (Basel) 2021; 11:life11020131. [PMID: 33567498 PMCID: PMC7915716 DOI: 10.3390/life11020131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Revised: 02/03/2021] [Accepted: 02/05/2021] [Indexed: 11/18/2022] Open
Abstract
(1) Background: many rare cystic fibrosistransmembrane conductance regulator (CFTR) mutations remain poorly characterized with regard to functional consequences of the mutation. We present the clinical features of two pediatric cystic fibrosis (CF) subjects who are heterozygous for F1099L (c.3297C>G), one with G551D (a class III mutation) and one with 3849 + 10kbC->T (a class V mutation). We also identified the molecular defect(s) that are associated with F1099L mutation to correlate with the clinical features that we observed; (2) Methods: clinical findings and history were extracted from the electronic medical record and de-identified. F1099L-CFTR protein expression level and maturation status, channel function, and the effects of CFTR modulation on these characteristics were investigated using western blotting and iodide efflux assay; (3) Results: these two subjects have mild CF phenotypes when F1099L is combined with two known disease-causing mutations. F1099L-CFTR has a moderate defect in processing and maturation, causing fewer CFTR channels at the cell surface and, therefore, impaired channel activities. These defects could be effectively corrected using VX-809 (lumacaftor); and, (4) Conclusions: our biochemical data correlate with the disease manifestations and suggest that F1099L is potentially a CF-causing mutation. The study expands our knowledge of rare CFTR mutations and may help in developing effective therapies for subjects with F1099L mutation.
Collapse
|
36
|
Linsdell P. On the relationship between anion binding and chloride conductance in the CFTR anion channel. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2021; 1863:183558. [PMID: 33444622 DOI: 10.1016/j.bbamem.2021.183558] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 12/21/2020] [Accepted: 12/29/2020] [Indexed: 12/26/2022]
Abstract
Mutations at many sites within the cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel pore region result in changes in chloride conductance. Although chloride binding in the pore - as well as interactions between concurrently bound chloride ions - are thought to be important facets of the chloride permeation mechanism, little is known about the relationship between anion binding and chloride conductance. The present work presents a comprehensive investigation of a number of anion binding properties in different pore mutants with differential effects on chloride conductance. When multiple pore mutants are compared, conductance appears best correlated with the ability of anions to bind to the pore when it is already occupied by chloride ions. In contrast, conductance was not correlated with biophysical measures of anion:anion interactions inside the pore. Although these findings suggest anion binding is required for high conductance, mutations that strengthened anion binding had very little effect on conductance, especially at high chloride concentrations, suggesting that the wild-type CFTR pore is already close to saturated with chloride ions. These results are used to support a revised model of chloride permeation in CFTR in which the overall chloride occupancy of multiple loosely-defined chloride binding sites results in high chloride conductance through the pore.
Collapse
Affiliation(s)
- Paul Linsdell
- Department of Physiology & Biophysics, Dalhousie University, Halifax, Nova Scotia, Canada.
| |
Collapse
|
37
|
Haq IJ, Althaus M, Gardner AI, Yeoh HY, Joshi U, Saint-Criq V, Verdon B, Townshend J, O'Brien C, Ben-Hamida M, Thomas M, Bourke S, van der Sluijs P, Braakman I, Ward C, Gray MA, Brodlie M. Clinical and molecular characterization of the R751L-CFTR mutation. Am J Physiol Lung Cell Mol Physiol 2020; 320:L288-L300. [PMID: 33296276 PMCID: PMC8476205 DOI: 10.1152/ajplung.00137.2020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Cystic fibrosis (CF) arises from mutations in the CF transmembrane conductance regulator (CFTR) gene, resulting in progressive and life-limiting respiratory disease. R751L is a rare CFTR mutation that is poorly characterized. Our aims were to describe the clinical and molecular phenotypes associated with R751L. Relevant clinical data were collected from three heterozygote individuals harboring R751L (2 patients with G551D/R751L and 1 with F508del/R751L). Assessment of R751L-CFTR function was made in primary human bronchial epithelial cultures (HBEs) and Xenopus oocytes. Molecular properties of R751L-CFTR were investigated in the presence of known CFTR modulators. Although sweat chloride was elevated in all three patients, the clinical phenotype associated with R751L was mild. Chloride secretion in F508del/R751L HBEs was reduced compared with non-CF HBEs and associated with a reduction in sodium absorption by the epithelial sodium channel (ENaC). However, R751L-CFTR function in Xenopus oocytes, together with folding and cell surface transport of R751L-CFTR, was not different from wild-type CFTR. Overall, R751L-CFTR was associated with reduced sodium chloride absorption but had functional properties similar to wild-type CFTR. This is the first report of R751L-CFTR that combines clinical phenotype with characterization of functional and biological properties of the mutant channel. Our work will build upon existing knowledge of mutations within this region of CFTR and, importantly, inform approaches for clinical management. Elevated sweat chloride and reduced chloride secretion in HBEs may be due to alternative non-CFTR factors, which require further investigation.
Collapse
Affiliation(s)
- Iram J Haq
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom.,Paediatric Respiratory Medicine, Great North Children's Hospital, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, United Kingdom
| | - Mike Althaus
- Institute for Functional Gene Analytics, Department of Natural Sciences, Bonn-Rhein-Sieg University of Applied Sciences, Rheinbach, Germany
| | - Aaron Ions Gardner
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Hui Ying Yeoh
- Cellular Protein Chemistry, Science4Life, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Urjita Joshi
- Cellular Protein Chemistry, Science4Life, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Vinciane Saint-Criq
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Bernard Verdon
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Jennifer Townshend
- Paediatric Respiratory Medicine, Great North Children's Hospital, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, United Kingdom
| | - Christopher O'Brien
- Paediatric Respiratory Medicine, Great North Children's Hospital, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, United Kingdom
| | - Mahfud Ben-Hamida
- Department of Paediatrics, West Cumberland Hospital, Whitehaven, United Kingdom
| | - Matthew Thomas
- Paediatric Respiratory Medicine, Great North Children's Hospital, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, United Kingdom
| | - Stephen Bourke
- Respiratory Medicine, Royal Victoria Infirmary, Newcastle upon Tyne, United Kingdom
| | - Peter van der Sluijs
- Cellular Protein Chemistry, Science4Life, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Ineke Braakman
- Cellular Protein Chemistry, Science4Life, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Chris Ward
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Michael A Gray
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Malcolm Brodlie
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom.,Paediatric Respiratory Medicine, Great North Children's Hospital, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, United Kingdom
| |
Collapse
|
38
|
Kroll T, Prescher M, Smits SHJ, Schmitt L. Structure and Function of Hepatobiliary ATP Binding Cassette Transporters. Chem Rev 2020; 121:5240-5288. [PMID: 33201677 DOI: 10.1021/acs.chemrev.0c00659] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The liver is beyond any doubt the most important metabolic organ of the human body. This function requires an intensive crosstalk within liver cellular structures, but also with other organs. Membrane transport proteins are therefore of upmost importance as they represent the sensors and mediators that shuttle signals from outside to the inside of liver cells and/or vice versa. In this review, we summarize the known literature of liver transport proteins with a clear emphasis on functional and structural information on ATP binding cassette (ABC) transporters, which are expressed in the human liver. These primary active membrane transporters form one of the largest families of membrane proteins. In the liver, they play an essential role in for example bile formation or xenobiotic export. Our review provides a state of the art and comprehensive summary of the current knowledge of hepatobiliary ABC transporters. Clearly, our knowledge has improved with a breath-taking speed over the last few years and will expand further. Thus, this review will provide the status quo and will lay the foundation for new and exciting avenues in liver membrane transporter research.
Collapse
Affiliation(s)
- Tim Kroll
- Institute of Biochemistry, Heinrich Heine University Düsseldorf, Universitätsstrasse 1, 40225 Düsseldorf, Germany
| | - Martin Prescher
- Institute of Biochemistry, Heinrich Heine University Düsseldorf, Universitätsstrasse 1, 40225 Düsseldorf, Germany
| | - Sander H J Smits
- Institute of Biochemistry, Heinrich Heine University Düsseldorf, Universitätsstrasse 1, 40225 Düsseldorf, Germany.,Center for Structural Studies, Heinrich Heine University Düsseldorf, Universitätsstrasse 1, 40225 Düsseldorf, Germany
| | - Lutz Schmitt
- Institute of Biochemistry, Heinrich Heine University Düsseldorf, Universitätsstrasse 1, 40225 Düsseldorf, Germany
| |
Collapse
|
39
|
de Jonge HR, Ardelean MC, Bijvelds MJC, Vergani P. Strategies for cystic fibrosis transmembrane conductance regulator inhibition: from molecular mechanisms to treatment for secretory diarrhoeas. FEBS Lett 2020; 594:4085-4108. [PMID: 33113586 PMCID: PMC7756540 DOI: 10.1002/1873-3468.13971] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 09/22/2020] [Accepted: 10/15/2020] [Indexed: 02/06/2023]
Abstract
Cystic fibrosis transmembrane conductance regulator (CFTR) is an unusual ABC transporter. It acts as an anion‐selective channel that drives osmotic fluid transport across many epithelia. In the gut, CFTR is crucial for maintaining fluid and acid‐base homeostasis, and its activity is tightly controlled by multiple neuro‐endocrine factors. However, microbial toxins can disrupt this intricate control mechanism and trigger protracted activation of CFTR. This results in the massive faecal water loss, metabolic acidosis and dehydration that characterize secretory diarrhoeas, a major cause of malnutrition and death of children under 5 years of age. Compounds that inhibit CFTR could improve emergency treatment of diarrhoeal disease. Drawing on recent structural and functional insight, we discuss how existing CFTR inhibitors function at the molecular and cellular level. We compare their mechanisms of action to those of inhibitors of related ABC transporters, revealing some unexpected features of drug action on CFTR. Although challenges remain, especially relating to the practical effectiveness of currently available CFTR inhibitors, we discuss how recent technological advances might help develop therapies to better address this important global health need.
Collapse
Affiliation(s)
- Hugo R. de Jonge
- Department of Gastroenterology & HepatologyErasmus University Medical CenterRotterdamThe Netherlands
| | - Maria C. Ardelean
- Department of Neuroscience, Physiology and PharmacologyUniversity College LondonUK
- Department of Natural SciencesUniversity College LondonUK
| | - Marcel J. C. Bijvelds
- Department of Gastroenterology & HepatologyErasmus University Medical CenterRotterdamThe Netherlands
| | - Paola Vergani
- Department of Neuroscience, Physiology and PharmacologyUniversity College LondonUK
| |
Collapse
|
40
|
Silva IAL, Doušová T, Ramalho S, Centeio R, Clarke LA, Railean V, Botelho HM, Holubová A, Valášková I, Yeh JT, Hwang TC, Farinha CM, Kunzelmann K, Amaral MD. Organoids as a personalized medicine tool for ultra-rare mutations in cystic fibrosis: The case of S955P and 1717-2A>G. Biochim Biophys Acta Mol Basis Dis 2020; 1866:165905. [PMID: 32730979 PMCID: PMC7484254 DOI: 10.1016/j.bbadis.2020.165905] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 07/07/2020] [Accepted: 07/22/2020] [Indexed: 12/12/2022]
Abstract
BACKGROUND For most of the >2000 CFTR gene variants reported, neither the associated disease liability nor the underlying basic defect are known, and yet these are essential for disease prognosis and CFTR-based therapeutics. Here we aimed to characterize two ultra-rare mutations - 1717-2A > G (c.1585-2A > G) and S955P (p.Ser955Pro) - as case studies for personalized medicine. METHODS Patient-derived rectal biopsies and intestinal organoids from two individuals with each of these mutations and F508del (p.Phe508del) in the other allele were used to assess CFTR function, response to modulators and RNA splicing pattern. In parallel, we used cellular models to further characterize S955P independently of F508del and to assess its response to CFTR modulators. RESULTS Results in both rectal biopsies and intestinal organoids from both patients evidence residual CFTR function. Further characterization shows that 1717-2A > G leads to alternative splicing generating <1% normal CFTR mRNA and that S955P affects CFTR gating. Finally, studies in organoids predict that both patients are responders to VX-770 alone and even more to VX-770 combined with VX-809 or VX-661, although to different levels. CONCLUSION This study demonstrates the high potential of personalized medicine through theranostics to extend the label of approved drugs to patients with rare mutations.
Collapse
Affiliation(s)
- Iris A L Silva
- University of Lisboa, Faculty of Sciences, BioISI - Biosystems & Integrative Sciences Institute, Campo Grande, C8 bdg, 1749-016 Lisboa, Portugal
| | - Tereza Doušová
- Department of Pediatrics, 2nd Faculty of Medicine, Charles University and University Hospital Motol, V Uvalu 84,Prague 5, 150 06 Prague, Czech Republic
| | - Sofia Ramalho
- University of Lisboa, Faculty of Sciences, BioISI - Biosystems & Integrative Sciences Institute, Campo Grande, C8 bdg, 1749-016 Lisboa, Portugal
| | - Raquel Centeio
- University of Lisboa, Faculty of Sciences, BioISI - Biosystems & Integrative Sciences Institute, Campo Grande, C8 bdg, 1749-016 Lisboa, Portugal
| | - Luka A Clarke
- University of Lisboa, Faculty of Sciences, BioISI - Biosystems & Integrative Sciences Institute, Campo Grande, C8 bdg, 1749-016 Lisboa, Portugal
| | - Violeta Railean
- University of Lisboa, Faculty of Sciences, BioISI - Biosystems & Integrative Sciences Institute, Campo Grande, C8 bdg, 1749-016 Lisboa, Portugal
| | - Hugo M Botelho
- University of Lisboa, Faculty of Sciences, BioISI - Biosystems & Integrative Sciences Institute, Campo Grande, C8 bdg, 1749-016 Lisboa, Portugal
| | - Andrea Holubová
- Department of Biology and Medical Genetics, 2nd Faculty of Medicine, Charles University and University Hospital Motol, V Uvalu 84,Prague 5, 150 06 Prague, Czech Republic
| | - Iveta Valášková
- Department of Medical Genetics, Masaryk University Brno and University Hospital Brno, Jihlavská 20, Brno 625 00, Czech Republic
| | - Jiunn-Tyng Yeh
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO, United States of America
| | - Tzyh-Chang Hwang
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO, United States of America
| | - Carlos M Farinha
- University of Lisboa, Faculty of Sciences, BioISI - Biosystems & Integrative Sciences Institute, Campo Grande, C8 bdg, 1749-016 Lisboa, Portugal
| | - Karl Kunzelmann
- Institut für Physiologie, Universität Regensburg, Universitätsstraße 31, D-93053 Regensburg, Germany
| | - Margarida D Amaral
- University of Lisboa, Faculty of Sciences, BioISI - Biosystems & Integrative Sciences Institute, Campo Grande, C8 bdg, 1749-016 Lisboa, Portugal.
| |
Collapse
|
41
|
Fonseca C, Bicker J, Alves G, Falcão A, Fortuna A. Cystic fibrosis: Physiopathology and the latest pharmacological treatments. Pharmacol Res 2020; 162:105267. [PMID: 33127556 DOI: 10.1016/j.phrs.2020.105267] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Revised: 10/12/2020] [Accepted: 10/18/2020] [Indexed: 12/18/2022]
Abstract
Cystic fibrosis (CF) is a lethal autosomal recessive genetic disease, caused by a mutation in the cystic fibrosis transmembrane conductance regulator gene (CFTR), which primarily affects the lungs and digestive system. This gene encodes the CFTR protein, a distinctive membrane transporter of the ATP-binding cassette (ABC) superfamily. It functions as a chloride channel, allowing the balance and transport of chloride through the apical membrane of epithelial cells. Due to its ubiquitous location, mutations in the CFTR gene trigger multiple changes in ion transport and metabolic pathways, affecting various organs, as it will be herein explained. Pulmonary impairment is the most characteristic comorbidity of CF and respiratory failure is the main cause of death. This review presents the importance of an early diagnosis of CF to establish, as soon as possible, a primary therapy for symptomatic prevention and relief. It also mentions new therapeutic approaches that include CFTR modulators. They are correctors and/or potentiators of the deficient CFTR channel. In an attempt to overcome the disadvantages of CFTR modulators, the application of biotechnology techniques is addressed, such as gene therapy, gene editing, RNA therapy and therapeutic microRNAs. The potential of the intranasal administration route is another presented aspect.
Collapse
Affiliation(s)
- Carla Fonseca
- University of Coimbra, Faculty of Pharmacy, Coimbra, Portugal
| | - Joana Bicker
- University of Coimbra, Faculty of Pharmacy, Coimbra, Portugal; University of Coimbra, Coimbra Institute for Biomedical Imaging and Translational Research, Coimbra, Portugal
| | - Gilberto Alves
- CICS-UBI - Health Sciences Research Centre, University of Beira Interior, Covilhã, Portugal
| | - Amílcar Falcão
- University of Coimbra, Faculty of Pharmacy, Coimbra, Portugal; University of Coimbra, Coimbra Institute for Biomedical Imaging and Translational Research, Coimbra, Portugal
| | - Ana Fortuna
- University of Coimbra, Faculty of Pharmacy, Coimbra, Portugal; University of Coimbra, Coimbra Institute for Biomedical Imaging and Translational Research, Coimbra, Portugal.
| |
Collapse
|
42
|
Montenarh M, Götz C. Protein kinase CK2 and ion channels (Review). Biomed Rep 2020; 13:55. [PMID: 33082952 PMCID: PMC7560519 DOI: 10.3892/br.2020.1362] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 07/28/2020] [Indexed: 12/18/2022] Open
Abstract
Protein kinase CK2 appears as a tetramer or higher molecular weight oligomer composed of catalytic CK2α, CK2α' subunits and non-catalytic regulatory CK2β subunits or as individual subunits. It is implicated in a variety of different regulatory processes, such as Akt signalling, splicing and DNA repair within eukaryotic cells. The present review evaluates the influence of CK2 on ion channels in the plasma membrane. CK2 phosphorylates platform proteins such as calmodulin and ankyrin G, which bind to channel proteins for a physiological transport to and positioning into the membrane. In addition, CK2 directly phosphorylates a variety of channel proteins directly to regulate opening and closing of the channels. Thus, modulation of CK2 activities by specific inhibitors, by siRNA technology or by CRISPR/Cas technology has an influence on intracellular ion concentrations and thereby on cellular signalling. The physiological regulation of the intracellular ion concentration is important for cell survival and correct intracellular signalling. Disturbance of this regulation results in a variety of different diseases including epilepsy, heart failure, cystic fibrosis and diabetes. Therefore, these effects should be considered when using CK2 inhibition as a treatment option for cancer.
Collapse
Affiliation(s)
- Mathias Montenarh
- Medical Biochemistry and Molecular Biology, Saarland University, D-66424 Homburg, Saarland, Germany
| | - Claudia Götz
- Medical Biochemistry and Molecular Biology, Saarland University, D-66424 Homburg, Saarland, Germany
| |
Collapse
|
43
|
Rodrat M, Jantarajit W, Ng DRS, Harvey BSJ, Liu J, Wilkinson WJ, Charoenphandhu N, Sheppard DN. Carbon monoxide-releasing molecules inhibit the cystic fibrosis transmembrane conductance regulator Cl - channel. Am J Physiol Lung Cell Mol Physiol 2020; 319:L997-L1009. [PMID: 32936026 DOI: 10.1152/ajplung.00440.2019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The gasotransmitter carbon monoxide (CO) regulates fluid and electrolyte movements across epithelial tissues. However, its action on anion channels is incompletely understood. Here, we investigate the direct action of CO on the cystic fibrosis transmembrane conductance regulator (CFTR) by applying CO-releasing molecules (CO-RMs) to the intracellular side of excised inside-out membrane patches from cells heterologously expressing wild-type human CFTR. Addition of increasing concentrations of tricarbonyldichlororuthenium(II) dimer (CORM-2) (1-300 μM) inhibited CFTR channel activity, whereas the control RuCl3 (100 μM) was without effect. CORM-2 predominantly inhibited CFTR by decreasing the frequency of channel openings and, hence, open probability (Po). But, it also reduced current flow through open channels with very fast kinetics, particularly at elevated concentrations. By contrast, the chemically distinct CO-releasing molecule CORM-3 inhibited CFTR by decreasing Po without altering current flow through open channels. Neither depolarizing the membrane voltage nor raising the ATP concentration on the intracellular side of the membrane affected CFTR inhibition by CORM-2. Interestingly, CFTR inhibition by CORM-2, but not by CFTRinh-172, was prevented by prior enhancement of channel activity by the clinically approved CFTR potentiator ivacaftor. Similarly, when added after CORM-2, ivacaftor completely relieved CFTR inhibition. In conclusion, CORM-2 has complex effects on wild-type human CFTR consistent with allosteric inhibition and open-channel blockade. Inhibition of CFTR by CO-releasing molecules suggests that CO regulates CFTR activity and that the gasotransmitter has tissue-specific effects on epithelial ion transport. The action of ivacaftor on CFTR Cl- channels inhibited by CO potentially expands the drug's clinical utility.
Collapse
Affiliation(s)
- Mayuree Rodrat
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom.,Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, Thailand.,Department of Physiology, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Walailak Jantarajit
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom.,Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, Thailand.,Department of Physiology, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Demi R S Ng
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
| | - Bartholomew S J Harvey
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
| | - Jia Liu
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
| | | | - Narattaphol Charoenphandhu
- Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, Thailand.,Department of Physiology, Faculty of Science, Mahidol University, Bangkok, Thailand.,Institute of Molecular Biosciences, Mahidol University, Nakhon Pathom, Thailand.,The Academy of Science, The Royal Society of Thailand, Dusit, Bangkok, Thailand
| | - David N Sheppard
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
| |
Collapse
|
44
|
Editorial: Special Issue on "Therapeutic Approaches for Cystic Fibrosis". Int J Mol Sci 2020; 21:ijms21186657. [PMID: 32932926 PMCID: PMC7555172 DOI: 10.3390/ijms21186657] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 09/08/2020] [Accepted: 09/09/2020] [Indexed: 12/18/2022] Open
|
45
|
Novel frameshift variant of the CFTR gene: S511Lfs*2 from phenotype to molecular predictions. Mol Biol Rep 2020; 47:6463-6469. [DOI: 10.1007/s11033-020-05677-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 07/09/2020] [Accepted: 07/19/2020] [Indexed: 11/28/2022]
|
46
|
Liessi N, Pedemonte N, Armirotti A, Braccia C. Proteomics and Metabolomics for Cystic Fibrosis Research. Int J Mol Sci 2020; 21:ijms21155439. [PMID: 32751630 PMCID: PMC7432297 DOI: 10.3390/ijms21155439] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Revised: 07/18/2020] [Accepted: 07/27/2020] [Indexed: 12/20/2022] Open
Abstract
The aim of this review article is to introduce the reader to the state-of-the-art of the contribution that proteomics and metabolomics sciences are currently providing for cystic fibrosis (CF) research: from the understanding of cystic fibrosis transmembrane conductance regulator (CFTR) biology to biomarker discovery for CF diagnosis. Our work particularly focuses on CFTR post-translational modifications and their role in cellular trafficking as well as on studies that allowed the identification of CFTR molecular interactors. We also show how metabolomics is currently helping biomarker discovery in CF. The most recent advances in these fields are covered by this review, as well as some considerations on possible future scenarios for new applications.
Collapse
Affiliation(s)
- Nara Liessi
- Analytical Chemistry Lab, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy;
| | - Nicoletta Pedemonte
- U.O.C. Genetica Medica, IRCCS Giannina Gaslini, Via Gerolamo Gaslini 5, 16147 Genova, Italy;
| | - Andrea Armirotti
- Analytical Chemistry Lab, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy;
- Correspondence: ; Tel.: +39-010-2896-938
| | - Clarissa Braccia
- D3PharmaChemistry, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy;
| |
Collapse
|
47
|
Skitchenko RK, Usoltsev D, Uspenskaya M, Kajava AV, Guskov A. Census of halide-binding sites in protein structures. Bioinformatics 2020; 36:3064-3071. [PMID: 32022861 PMCID: PMC7214031 DOI: 10.1093/bioinformatics/btaa079] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 01/24/2020] [Accepted: 01/29/2020] [Indexed: 12/02/2022] Open
Abstract
Motivation Halides are negatively charged ions of halogens, forming fluorides (F−), chlorides (Cl−), bromides (Br−) and iodides (I−). These anions are quite reactive and interact both specifically and non-specifically with proteins. Despite their ubiquitous presence and important roles in protein function, little is known about the preferences of halides binding to proteins. To address this problem, we performed the analysis of halide–protein interactions, based on the entries in the Protein Data Bank. Results We have compiled a pipeline for the quick analysis of halide-binding sites in proteins using the available software. Our analysis revealed that all of halides are strongly attracted by the guanidinium moiety of arginine side chains, however, there are also certain preferences among halides for other partners. Furthermore, there is a certain preference for coordination numbers in the binding sites, with a correlation between coordination numbers and amino acid composition. This pipeline can be used as a tool for the analysis of specific halide–protein interactions and assist phasing experiments relying on halides as anomalous scatters. Availability and implementation All data described in this article can be reproduced via complied pipeline published at https://github.com/rostkick/Halide_sites/blob/master/README.md. Supplementary information Supplementary data are available at Bioinformatics online.
Collapse
Affiliation(s)
| | - Dmitrii Usoltsev
- Institute BioEngineering, ITMO University, Saint-Petersburg 197101, Russia
| | - Mayya Uspenskaya
- Institute BioEngineering, ITMO University, Saint-Petersburg 197101, Russia
| | - Andrey V Kajava
- Institute BioEngineering, ITMO University, Saint-Petersburg 197101, Russia.,Centre de Recherche en Biologie cellulaire de Montpellier (CRBM), UMR 5237 CNRS, Universite Montpellier, Montpellier 34293, France
| | - Albert Guskov
- Groningen Biomolecular Sciences & Biotechnology Institute, University of Groningen, Groningen 9747 AG, the Netherlands
| |
Collapse
|
48
|
Noël S, Sermet-Gaudelus I. Mucoviscidosis: fisiopatología, genética, aspectos clínicos y terapéuticos. EMC. PEDIATRIA 2020; 55:1-23. [PMID: 32288518 PMCID: PMC7147672 DOI: 10.1016/s1245-1789(20)43427-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
La mucoviscidosis es la enfermedad autosómica recesiva grave más frecuente que afecta a la población caucásica. En Francia, por ejemplo, la incidencia es de un caso por cada 4.500 nacimientos. Esta enfermedad se debe a mutaciones en el gen CFTR (cystic fibrosis transmembrane conductance regulator, regulador de conductancia transmembrana de la fibrosis quística), situado en el brazo largo del cromosoma 7, que codifica una proteína transmembrana implicada en la regulación del transporte transepitelial de iones cloruro (Cl–). En Francia, la mutación más frecuente (alrededor del 80% de los casos) es la deleción del aminoácido 508 (fenilalanina), denominada F508del. La ausencia o la disfunción de la proteína CFTR provoca un defecto en el transporte de Cl– y un aumento de la reabsorción de sal y agua, en particular en el epitelio bronquial, lo que conlleva una reducción del líquido de la superficie bronquial. Esta exocrinopatía generalizada conduce a la producción de «moco viscoso» (de ahí el nombre de mucoviscidosis), que obstruye varios sitios en el cuerpo, en particular el sistema respiratorio, el tracto digestivo y sus anexos (páncreas, vías biliares e hígado). La detección neonatal se ha generalizado desde 2002. La prueba del sudor es la prueba complementaria de referencia, validada por la identificación de dos mutaciones patógenas, para la confirmación del diagnóstico. El tratamiento es multidisciplinario. Se basa ante todo en la kinesiterapia respiratoria diaria y el tratamiento de las sobreinfecciones broncopulmonares, así como en las recomendaciones nutricionales con el uso de extractos pancreáticos. Es probable que el pronóstico, todavía muy desfavorable, se modifique con la llegada de terapias proteínicas o de edición de ácido ribonucleico o de gen.
Collapse
|
49
|
Kleizen B, Hunt JF, Callebaut I, Hwang TC, Sermet-Gaudelus I, Hafkemeyer S, Sheppard DN. CFTR: New insights into structure and function and implications for modulation by small molecules. J Cyst Fibros 2020; 19 Suppl 1:S19-S24. [DOI: 10.1016/j.jcf.2019.10.021] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 10/17/2019] [Accepted: 10/18/2019] [Indexed: 12/22/2022]
|
50
|
Chen JH. Protein kinase A phosphorylation potentiates cystic fibrosis transmembrane conductance regulator gating by relieving autoinhibition on the stimulatory C terminus of the regulatory domain. J Biol Chem 2020; 295:4577-4590. [PMID: 32102849 DOI: 10.1074/jbc.ra119.008427] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 02/25/2020] [Indexed: 01/12/2023] Open
Abstract
Cystic fibrosis transmembrane conductance regulator (CFTR) is a chloride channel activated by protein kinase A (PKA) phosphorylation on the regulatory (R) domain. Phosphorylation at several R domain residues stimulates ATP-dependent channel openings and closings, termed channel gating. To explore the protein segment responsible for channel potentiation and PKA-dependent activation, deletion mutations were constructed by removing one to three protein segments of the R domain including residues 708-759 (ΔR708-759), R760-783, and R784-835, each of which contains one or two PKA phosphorylation sites. Deletion of R708-759 or R760-783 had little effect on CFTR gating, whereas all mutations lacking R784-835 reduced CFTR activity by decreasing the mean burst duration and increasing the interburst interval (IBI). The data suggest that R784-835 plays a major role in stimulating CFTR gating. For ATP-associated regulation, ΔR784-835 had minor impact on gating potentiation by 2'dATP, CaATP, and pyrophosphate. Interestingly, introducing a phosphorylated peptide matching R809-835 shortened the IBI of ΔR708-835-CFTR. Consistently, ΔR815-835, but not ΔR784-814, enhanced IBI, whereas both reduced mean burst duration. These data suggest that the entirety of R784-835 is required for stabilizing the open state of CFTR; however, R815-835, through interactions with the channel, is dominant for enhancing the opening rate. Of note, PKA markedly decreased the IBI of ΔR708-783-CFTR. Conversely, the IBI of ΔR708-814-CFTR was short and PKA-independent. These data reveal that for stimulating CFTR gating, PKA phosphorylation may relieve R784-814-mediated autoinhibition that prevents IBI shortening by R815-835 This mechanism may elucidate how the R domain potentiates channel gating and may unveil CFTR stimulation by other protein kinases.
Collapse
Affiliation(s)
- Jeng-Haur Chen
- College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, Zhejiang Province 321004, China .,University of Hong Kong Shenzhen Institute of Research and Innovation, Shenzhen 518057, China .,Department of Internal Medicine and Howard Hughes Medical Institute, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
| |
Collapse
|