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Park H, Shin DH, Sim JR, Aum S, Lee MG. IRE1α kinase-mediated unconventional protein secretion rescues misfolded CFTR and pendrin. SCIENCE ADVANCES 2020; 6:eaax9914. [PMID: 32128399 PMCID: PMC7030921 DOI: 10.1126/sciadv.aax9914] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 12/04/2019] [Indexed: 05/02/2023]
Abstract
The most prevalent pathogenic mutations in the CFTR (ΔF508) and SLC26A4/pendrin (p.H723R), which cause cystic fibrosis and congenital hearing loss, respectively, evoke protein misfolding and subsequent defects in their cell surface trafficking. Here, we report that activation of the IRE1α kinase pathway can rescue the cell surface expression of ΔF508-CFTR and p.H723R-pendrin through a Golgi-independent unconventional protein secretion (UPS) route. In mammalian cells, inhibition of IRE1α kinase, but not inhibition of IRE1α endonuclease and the downstream effector XBP1, inhibited CFTR UPS. Treatment with the IRE1α kinase activator, (E)-2-(2-chlorostyryl)-3,5,6-trimethyl-pyrazine (CSTMP), rescued cell surface expression and functional activity of ΔF508-CFTR and p.H723R-pendrin. Treatment with a nontoxic dose of CSTMP to ΔF508-CFTR mice restored CFTR surface expression and CFTR-mediated anion transport in the mouse colon. These findings suggest that UPS activation via IRE1α kinase is a strategy to treat diseases caused by defective cell surface trafficking of membrane proteins, including ΔF508-CFTR and p.H723R-pendrin.
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Chung WY, Song M, Park J, Namkung W, Lee J, Kim H, Lee MG, Kim JY. Generation of ΔF508-CFTR T84 cell lines by CRISPR/Cas9-mediated genome editing. Biotechnol Lett 2016; 38:2023-2034. [DOI: 10.1007/s10529-016-2190-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Accepted: 08/18/2016] [Indexed: 12/13/2022]
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Kim J, Noh SH, Piao H, Kim DH, Kim K, Cha JS, Chung WY, Cho HS, Kim JY, Lee MG. Monomerization and ER Relocalization of GRASP Is a Requisite for Unconventional Secretion of CFTR. Traffic 2016; 17:733-53. [DOI: 10.1111/tra.12403] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 03/30/2016] [Accepted: 03/30/2016] [Indexed: 12/20/2022]
Affiliation(s)
- Jiyoon Kim
- Department of Pharmacology, Brain Korea 21 PLUS Project for Medical Sciences, Severance Biomedical Science Institute; Yonsei University College of Medicine; Seoul 120-752 Korea
| | - Shin Hye Noh
- Department of Pharmacology, Brain Korea 21 PLUS Project for Medical Sciences, Severance Biomedical Science Institute; Yonsei University College of Medicine; Seoul 120-752 Korea
| | - He Piao
- Department of Pharmacology, Brain Korea 21 PLUS Project for Medical Sciences, Severance Biomedical Science Institute; Yonsei University College of Medicine; Seoul 120-752 Korea
| | - Dong Hee Kim
- Department of Pharmacology, Brain Korea 21 PLUS Project for Medical Sciences, Severance Biomedical Science Institute; Yonsei University College of Medicine; Seoul 120-752 Korea
| | - Kuglae Kim
- Department of Systems Biology; Yonsei University College of Life Science and Biotechnology; Seoul 120-749 Korea
| | - Jeong Seok Cha
- Department of Systems Biology; Yonsei University College of Life Science and Biotechnology; Seoul 120-749 Korea
| | - Woo Young Chung
- Department of Pharmacology, Brain Korea 21 PLUS Project for Medical Sciences, Severance Biomedical Science Institute; Yonsei University College of Medicine; Seoul 120-752 Korea
| | - Hyun-Soo Cho
- Department of Systems Biology; Yonsei University College of Life Science and Biotechnology; Seoul 120-749 Korea
| | - Joo Young Kim
- Department of Pharmacology, Brain Korea 21 PLUS Project for Medical Sciences, Severance Biomedical Science Institute; Yonsei University College of Medicine; Seoul 120-752 Korea
| | - Min Goo Lee
- Department of Pharmacology, Brain Korea 21 PLUS Project for Medical Sciences, Severance Biomedical Science Institute; Yonsei University College of Medicine; Seoul 120-752 Korea
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Kim Y, Anderson MO, Park J, Lee MG, Namkung W, Verkman AS. Benzopyrimido-pyrrolo-oxazine-dione (R)-BPO-27 Inhibits CFTR Chloride Channel Gating by Competition with ATP. Mol Pharmacol 2015; 88:689-96. [PMID: 26174774 DOI: 10.1124/mol.115.098368] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Accepted: 07/13/2015] [Indexed: 12/16/2022] Open
Abstract
We previously reported that benzopyrimido-pyrrolo-oxazinedione BPO-27 [6-(5-bromofuran-2-yl)-7,9-dimethyl-8,10-dioxo-11-phenyl-7,8,9,10-tetrahydro-6H-benzo[b]pyrimido [4',5':3,4]pyrrolo [1,2-d][1,4]oxazine-2-carboxylic acid] inhibits the cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel with low nanomolar potency and reduces cystogenesis in a model of polycystic kidney disease. We used computational chemistry and patch-clamp to show that enantiomerically pure (R)-BPO-27 inhibits CFTR by competition with ATP, whereas (S)-BPO-27 is inactive. Docking computations using a homology model of CFTR structure suggested that (R)-BPO-27 binds near the canonical ATP binding site, and these findings were supported by molecular dynamics simulations showing a lower binding energy for the (R) versus (S) stereoisomers. Three additional lower-potency BPO-27 analogs were modeled in a similar fashion, with the binding energies predicted in the correct order. Whole-cell patch-clamp studies showed linear CFTR currents with a voltage-independent (R)-BPO-27 block mechanism. Single-channel recordings in inside-out patches showed reduced CFTR channel open probability and increased channel closed time by (R)-BPO-27 without altered unitary channel conductance. At a concentration of (R)-BPO-27 that inhibited CFTR chloride current by ∼50%, the EC50 for ATP activation of CFTR increased from 0.27 to 1.77 mM but was not changed by CFTRinh-172 [4-[[4-oxo-2-thioxo-3-[3-trifluoromethyl)phenyl]-5-thiazolidinylidene]methyl]benzoic acid], a thiazolidinone CFTR inhibitor that acts at a site distinct from the ATP binding site. Our results suggest that (R)-BPO-27 inhibition of CFTR involves competition with ATP.
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Affiliation(s)
- Yonjung Kim
- Department of Pharmacology, Brain Korea 21 PLUS Project for Medical Sciences, Yonsei University College of Medicine, Seoul, Korea (Y.K., M.G.L.); Department of Chemistry and Biochemistry, San Francisco State University, San Francisco, California (M.O.A.); College of Pharmacy, Yonsei Institute of Pharmaceutical Sciences, Yonsei University, Incheon, Korea (J.P., W.N.); and Departments of Medicine and Physiology, University of California, San Francisco, California (A.S.V.)
| | - Marc O Anderson
- Department of Pharmacology, Brain Korea 21 PLUS Project for Medical Sciences, Yonsei University College of Medicine, Seoul, Korea (Y.K., M.G.L.); Department of Chemistry and Biochemistry, San Francisco State University, San Francisco, California (M.O.A.); College of Pharmacy, Yonsei Institute of Pharmaceutical Sciences, Yonsei University, Incheon, Korea (J.P., W.N.); and Departments of Medicine and Physiology, University of California, San Francisco, California (A.S.V.)
| | - Jinhong Park
- Department of Pharmacology, Brain Korea 21 PLUS Project for Medical Sciences, Yonsei University College of Medicine, Seoul, Korea (Y.K., M.G.L.); Department of Chemistry and Biochemistry, San Francisco State University, San Francisco, California (M.O.A.); College of Pharmacy, Yonsei Institute of Pharmaceutical Sciences, Yonsei University, Incheon, Korea (J.P., W.N.); and Departments of Medicine and Physiology, University of California, San Francisco, California (A.S.V.)
| | - Min Goo Lee
- Department of Pharmacology, Brain Korea 21 PLUS Project for Medical Sciences, Yonsei University College of Medicine, Seoul, Korea (Y.K., M.G.L.); Department of Chemistry and Biochemistry, San Francisco State University, San Francisco, California (M.O.A.); College of Pharmacy, Yonsei Institute of Pharmaceutical Sciences, Yonsei University, Incheon, Korea (J.P., W.N.); and Departments of Medicine and Physiology, University of California, San Francisco, California (A.S.V.)
| | - Wan Namkung
- Department of Pharmacology, Brain Korea 21 PLUS Project for Medical Sciences, Yonsei University College of Medicine, Seoul, Korea (Y.K., M.G.L.); Department of Chemistry and Biochemistry, San Francisco State University, San Francisco, California (M.O.A.); College of Pharmacy, Yonsei Institute of Pharmaceutical Sciences, Yonsei University, Incheon, Korea (J.P., W.N.); and Departments of Medicine and Physiology, University of California, San Francisco, California (A.S.V.)
| | - A S Verkman
- Department of Pharmacology, Brain Korea 21 PLUS Project for Medical Sciences, Yonsei University College of Medicine, Seoul, Korea (Y.K., M.G.L.); Department of Chemistry and Biochemistry, San Francisco State University, San Francisco, California (M.O.A.); College of Pharmacy, Yonsei Institute of Pharmaceutical Sciences, Yonsei University, Incheon, Korea (J.P., W.N.); and Departments of Medicine and Physiology, University of California, San Francisco, California (A.S.V.)
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Arora K, Moon C, Zhang W, Yarlagadda S, Penmatsa H, Ren A, Sinha C, Naren AP. Stabilizing rescued surface-localized δf508 CFTR by potentiation of its interaction with Na(+)/H(+) exchanger regulatory factor 1. Biochemistry 2014; 53:4169-79. [PMID: 24945463 PMCID: PMC4081048 DOI: 10.1021/bi401263h] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
![]()
Cystic
fibrosis (CF) is a recessive genetic disease caused by mutations
in CFTR, a plasma-membrane-localized anion channel. The most common
mutation in CFTR, deletion of phenylalanine at residue 508 (ΔF508),
causes misfolding of CFTR resulting in little or no protein at the
plasma membrane. The CFTR corrector VX-809 shows promise for treating
CF patients homozygous for ΔF508. Here, we demonstrate the significance
of protein–protein interactions in enhancing the stability
of the ΔF508 CFTR mutant channel protein at the plasma membrane.
We determined that VX-809 prolongs the stability of ΔF508 CFTR
at the plasma membrane. Using competition-based assays, we demonstrated
that ΔF508 CFTR interacts poorly with Na+/H+ exchanger regulatory factor 1 (NHERF1) compared to wild-type CFTR,
and VX-809 significantly increased this binding affinity. We conclude
that stabilized CFTR–NHERF1 interaction is a determinant of
the functional efficiency of rescued ΔF508 CFTR. Our results
demonstrate the importance of macromolecular-complex formation in
stabilizing rescued mutant CFTR at the plasma membrane and suggest
this to be foundational for the development of a new generation of
effective CFTR-corrector-based therapeutics.
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Affiliation(s)
- Kavisha Arora
- Division of Pulmonary Medicine, Department of Pediatrics, Cincinnati Children's Hospital Medical Center , MLC2021 3333 Burnet Avenue, Cincinnati, Ohio 45229, United States
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Lee JH, Nam JH, Park J, Kang DW, Kim JY, Lee MG, Yoon JS. Regulation of SLC26A3 activity by NHERF4 PDZ-mediated interaction. Cell Signal 2012; 24:1821-30. [DOI: 10.1016/j.cellsig.2012.05.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Revised: 05/11/2012] [Accepted: 05/13/2012] [Indexed: 12/12/2022]
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Luciani A, Villella VR, Esposito S, Gavina M, Russo I, Silano M, Guido S, Pettoello-Mantovani M, Carnuccio R, Scholte B, De Matteis A, Maiuri MC, Raia V, Luini A, Kroemer G, Maiuri L. Targeting autophagy as a novel strategy for facilitating the therapeutic action of potentiators on ΔF508 cystic fibrosis transmembrane conductance regulator. Autophagy 2012; 8:1657-72. [PMID: 22874563 DOI: 10.4161/auto.21483] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Channel activators (potentiators) of cystic fibrosis (CF) transmembrane conductance regulator (CFTR), can be used for the treatment of the small subset of CF patients that carry plasma membrane-resident CFTR mutants. However, approximately 90% of CF patients carry the misfolded ΔF508-CFTR and are poorly responsive to potentiators, because ΔF508-CFTR is intrinsically unstable at the plasma membrane (PM) even if rescued by pharmacological correctors. We have demonstrated that human and mouse CF airways are autophagy deficient due to functional sequestration of BECN1 and that the tissue transglutaminase-2 inhibitor, cystamine, or antioxidants restore BECN1-dependent autophagy and reduce SQSTM1/p62 levels, thus favoring ΔF508-CFTR trafficking to the epithelial surface. Here, we investigated whether these treatments could facilitate the beneficial action of potentiators on ΔF508-CFTR homozygous airways. Cystamine or the superoxide dismutase (SOD)/catalase-mimetic EUK-134 stabilized ΔF508-CFTR at the plasma membrane of airway epithelial cells and sustained the expression of CFTR at the epithelial surface well beyond drug withdrawal, overexpressing BECN1 and depleting SQSTM1. This facilitates the beneficial action of potentiators in controlling inflammation in ex vivo ΔF508-CFTR homozygous human nasal biopsies and in vivo in mouse ΔF508-CFTR lungs. Direct depletion of Sqstm1 by shRNAs in vivo in ΔF508-CFTR mice synergized with potentiators in sustaining surface CFTR expression and suppressing inflammation. Cystamine pre-treatment restored ΔF508-CFTR response to the CFTR potentiators genistein, Vrx-532 or Vrx-770 in freshly isolated brushed nasal epithelial cells from ΔF508-CFTR homozygous patients. These findings delineate a novel therapeutic strategy for the treatment of CF patients with the ΔF508-CFTR mutation in which patients are first treated with cystamine and subsequently pulsed with CFTR potentiators.
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Affiliation(s)
- Alessandro Luciani
- European Institute for Research in Cystic Fibrosis, San Raffaele Scientific Institute, Milan, Italy
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Gee HY, Noh SH, Tang BL, Kim KH, Lee MG. Rescue of ΔF508-CFTR trafficking via a GRASP-dependent unconventional secretion pathway. Cell 2011; 146:746-60. [PMID: 21884936 DOI: 10.1016/j.cell.2011.07.021] [Citation(s) in RCA: 242] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2011] [Revised: 06/04/2011] [Accepted: 07/08/2011] [Indexed: 12/14/2022]
Abstract
The most prevalent disease-causing mutation of CFTR is the deletion of Phe508 (ΔF508), which leads to defects in conventional Golgi-mediated exocytosis and cell surface expression. We report that ΔF508-CFTR surface expression can be rescued in vitro and in vivo by directing it to an unconventional GRASP-dependent secretion pathway. An integrated molecular and physiological analysis indicates that mechanisms associated with ER stress induce cell surface trafficking of the ER core-glycosylated wild-type and ΔF508-CFTR via the GRASP-dependent pathway. Phosphorylation of a specific site of GRASP and the PDZ-based interaction between GRASP and CFTR are critical for this unconventional surface trafficking. Remarkably, transgenic expression of GRASP in ΔF508-CFTR mice restores CFTR function and rescues mouse survival without apparent toxicity. These findings provide insight into how unconventional protein secretion is activated, and offer a potential therapeutic strategy for the treatment of cystic fibrosis and perhaps diseases stemming from other misfolded proteins.
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Affiliation(s)
- Heon Yung Gee
- Department of Pharmacology, Brain Korea 21 Project for Medical Sciences, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul 120-752, Korea
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Borthwick LA, Botha P, Verdon B, Brodlie MJ, Gardner A, Bourn D, Johnson GE, Gray MA, Fisher AJ. Is CFTR-delF508 really absent from the apical membrane of the airway epithelium? PLoS One 2011; 6:e23226. [PMID: 21826241 PMCID: PMC3149652 DOI: 10.1371/journal.pone.0023226] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2011] [Accepted: 07/10/2011] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Understanding where mutant CFTR is localised in airway epithelia is essential in guiding the best therapeutic approach to correct the dysfunction of the CFTR protein. The widely held paradigm is that CF patients harbouring the commonest mutation, CFTR-delF508, trap CFTR within the endoplasmic reticulum and target it for degradation. However there are conflicting reports concerning expression and localisation of CFTR-delF508 in lung tissue. To attempt to resolve this fundamental issue we developed a novel approach to measure CFTR-delF508 in the lower airways of patients who have undergone lung transplantation for advanced CF. By sampling CF and non-CF epithelium simultaneously from the same individual, confounding factors of different airway microenvironments which may have influenced previous observations can be overcome. METHODS Epithelia sampled by bronchial brushing above (CF) and below (non-CF) the bronchial anastomosis were stained for CFTR and the localisation and level of expression assessed (n = 12). RESULTS There was no significant difference in the proportion of tall columnar cells showing CFTR immunostaining as a discrete band at the apical membrane in cells harbouring the CFTR-delF508 mutation compared to non-CF cells (p = 0.21, n = 12). However, the amount of CFTR expressed at the apical surface was reduced by ∼50% in CF cells compared to non-CF cells (p = 0.04, n = 5). CONCLUSIONS Our novel observation challenges the prevailing paradigm that CFTR is essentially absent from the apical membrane of respiratory cells harbouring the CFTR-delF508 mutation. Moreover, it raises the possibility that the new generation of CFTR potentiators may offer a realistic therapeutic option for CF patients.
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Affiliation(s)
- Lee A. Borthwick
- Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Phil Botha
- Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Bernard Verdon
- Institute for Cell & Molecular Biosciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Malcolm J. Brodlie
- Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Aaron Gardner
- Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - David Bourn
- Institute of Human Genetics, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Gail E. Johnson
- Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Mike A. Gray
- Institute for Cell & Molecular Biosciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Andrew J. Fisher
- Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom
- * E-mail:
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Gee HY, Tang BL, Kim KH, Lee MG. Syntaxin 16 binds to cystic fibrosis transmembrane conductance regulator and regulates its membrane trafficking in epithelial cells. J Biol Chem 2010; 285:35519-27. [PMID: 20826815 DOI: 10.1074/jbc.m110.162438] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The cystic fibrosis transmembrane conductance regulator (CFTR) is a key membrane protein in the complex network of epithelial ion transporters regulating epithelial permeability. Syntaxins are one of the major determinants in the intracellular trafficking and membrane targeting of secretory proteins. In the present study we demonstrate the biochemical and functional association between CFTR and syntaxin 16 (STX16) that mediates vesicle transport within the early/late endosomes and trans-Golgi network. Immunoprecipitation experiments in rat colon and T84 human colonic epithelial cells indicate that STX16 associates with CFTR. Further analyses using the domain-specific pulldown assay reveal that the helix domain of STX16 directly interacts with the N-terminal region of CFTR. Immunostainings in rat colon and T84 cells show that CFTR and STX16 highly co-localize at the apical and subapical regions of epithelial cells. Interestingly, CFTR-associated chloride current was reduced by the knockdown of STX16 expression in T84 cells. Surface biotinylation and recycling assays indicate that the reduction in CFTR chloride current is due to decreased CFTR expression on the plasma membrane. These results suggest that STX16 mediates recycling of CFTR and constitutes an important component of CFTR trafficking machinery in intestinal epithelial cells.
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Affiliation(s)
- Heon Yung Gee
- Department of Pharmacology, Institute of Gastroenterology, and Brain Korea 21 Project for Medical Sciences, Yonsei University College of Medicine, Seoul 120-752, Korea
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Gee HY, Kim YW, Jo MJ, Namkung W, Kim JY, Park HW, Kim KS, Kim H, Baba A, Yang J, Kim E, Kim KH, Lee MG. Synaptic scaffolding molecule binds to and regulates vasoactive intestinal polypeptide type-1 receptor in epithelial cells. Gastroenterology 2009; 137:607-17, 617.e1-4. [PMID: 19642226 DOI: 10.1053/j.gastro.2009.01.065] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
BACKGROUND & AIMS Vasoactive intestinal polypeptide (VIP) is a principal regulator of fluid and electrolyte secretion in the gastrointestinal system. The VIP type-1 receptor (VPAC1), a class II G-protein-coupled receptor, contains a putative C-terminal PDZ-binding motif. A yeast 2-hybrid screen indicated that the C-terminus of VPAC1 bound to the PDZ domain of synaptic scaffolding molecule (S-SCAM, also known as membrane-associated guanylate kinase inverted-2 [MAGI-2]). We analyzed the association between S-SCAM and VPAC1. METHODS The biochemical properties and physiologic significance of the interaction between VPAC1 and S-SCAM were examined in heterologous expression systems, T84 colonic epithelial cells, and human pancreas and colon tissues using an integrated molecular and physiologic approach. RESULTS The physical interaction between VPAC1 and S-SCAM was confirmed by immunoprecipitation in HEK 293 mammalian cells and human pancreatic and colonic tissues. Immunocytochemical analysis indicated that S-SCAM recruited VPAC1 to the junctional area near the apical end of the lateral membrane in T84 cells. Several lines of evidence revealed that S-SCAM inhibits VPAC1 activation. Overexpression of S-SCAM inhibited VPAC1-mediated cAMP production and agonist-induced VPAC1 internalization in HEK 293 and HeLa cells. In addition, S-SCAM decreased the VPAC1-mediated current through the cystic fibrosis transmembrane conductance regulator in Xenopus oocytes, especially at low concentrations of VIP. Importantly, loss of S-SCAM increased VIP-induced short-circuit currents in T84 monolayers, which endogenously express VPAC1 and S-SCAM. CONCLUSIONS S-SCAM/MAGI-2 interacts with and regulates VPAC1 intracellular localization in epithelial cells and inhibits VPAC1 agonist-induced activation and internalization.
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Affiliation(s)
- Heon Yung Gee
- Department of Pharmacology and Brain Korea 21 Project for Medical Science, Institute of Gastroenterology, Yonsei University College of Medicine, Seoul, Korea
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12
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Namkung W, Yoon JS, Kim KH, Lee MG. PAR2 exerts local protection against acute pancreatitis via modulation of MAP kinase and MAP kinase phosphatase signaling. Am J Physiol Gastrointest Liver Physiol 2008; 295:G886-94. [PMID: 18755806 DOI: 10.1152/ajpgi.00053.2008] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
During acute pancreatitis, protease-activated receptor 2 (PAR2) can be activated by interstitially released trypsin. In the mild form of pancreatitis, PAR2 activation exerts local protection against intrapancreatic damage, whereas, in the severe form of pancreatitis, PAR2 activation mediates some systemic complications. This study aimed to identify the molecular mechanisms of PAR2-mediated protective effects against intrapancreatic damage. A mild form of acute pancreatitis was induced by an intraperitoneal injection of caerulein (40 microg/kg) in rats. Effects of PAR2 activation on intrapancreatic damage and on mitogen-activated protein (MAP) kinase signaling were assessed. Caerulein treatment activated extracellular signal-regulated kinase (ERK) and c-Jun NH(2)-terminal kinase (JNK) within 15 min and maintained phosphorylation of ERK and JNK for 2 h in the rat pancreas. Although PAR2 activation by the pretreatment with PAR2-activating peptide (AP) itself increased ERK phosphorylation in rat pancreas, the same treatment remarkably decreased caerulein-induced activation of ERK and JNK principally by accelerating their dephosphorylation. Inhibition of ERK and JNK phosphorylation by the pretreatment with MAP/ERK kinase (MEK) or JNK inhibitors decreased caerulein-induced pancreatic damage that was similar to the effect induced by PAR2-AP. Notably, in caerulein-treated rats, PAR2-AP cotreatment highly increased the expression of a group of MAP kinase phosphatases (MKPs) that deactivate ERK and JNK. The above results imply that downregulation of MAP kinase signaling by MKP induction is a key mechanism involved in the protective effects of PAR2 activation on caerulein-induced intrapancreatic damage.
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Affiliation(s)
- Wan Namkung
- Dept. of Pharmacology, Yonsei Univ. College of Medicine, Seoul 120-752, Korea
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Lee JH, Richter W, Namkung W, Kim KH, Kim E, Conti M, Lee MG. Dynamic regulation of cystic fibrosis transmembrane conductance regulator by competitive interactions of molecular adaptors. J Biol Chem 2007; 282:10414-22. [PMID: 17244609 DOI: 10.1074/jbc.m610857200] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Disorganized ion transport caused by hypo- or hyperfunctioning of the cystic fibrosis transmembrane conductance regulator (CFTR) can be detrimental and may result in life-threatening diseases such as cystic fibrosis or secretory diarrhea. Thus, CFTR is controlled by elaborate positive and negative regulations for an efficient homeostasis. It has been shown that expression and activity of CFTR can be regulated either positively or negatively by PDZ (PSD-95/discs large/ZO-1) domain-based adaptors. Although a positive regulation by PDZ domain-based adaptors such as EBP50/NHERF1 is established, the mechanisms for negative regulation of the CFTR by Shank2, as well as the effects of multiple adaptor interactions, are not known. Here we demonstrate a physical and physiological competition between EBP50-CFTR and Shank2-CFTR associations and the dynamic regulation of CFTR activity by these positive and negative interactions using the surface plasmon resonance assays and consecutive patch clamp experiments. Furthermore whereas EBP50 recruits a cAMP-dependent protein kinase (PKA) complex to CFTR, Shank2 was found to be physically and functionally associated with the cyclic nucleotide phosphodiesterase PDE4D that precludes cAMP/PKA signals in epithelial cells and mouse brains. These findings strongly suggest that balanced interactions between the membrane transporter and multiple PDZ-based adaptors play a critical role in the homeostatic regulation of epithelial transport and possibly the membrane transport in other tissues.
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Affiliation(s)
- Ji Hyun Lee
- Department of Pharmacology, Institute of Gastroenterology, Yonsei University College of Medicine, Seoul 120-752, Korea
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Okiyoneda T, Niibori A, Harada K, Kohno T, Hashimoto Y, Kusuhara H, Takada T, Shuto T, Suico MA, Sugiyama Y, Kai H. Bafilomycin A1-sensitive pathway is required for the maturation of cystic fibrosis transmembrane conductance regulator. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2006; 1763:1017-23. [PMID: 17005267 DOI: 10.1016/j.bbamcr.2006.08.032] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2006] [Revised: 07/03/2006] [Accepted: 08/21/2006] [Indexed: 11/22/2022]
Abstract
Cystic fibrosis (CF) is the most common lethal genetic disease in Caucasians caused by the trafficking defects of CF transmembrane conductance regulator (CFTR), which is a cAMP-dependent Cl- channel at the plasma membrane. The trafficking pathway of CFTR is thought to be non-conventional because CFTR maturation is inhibited by the dysfunction of syntaxin 13, which is involved in protein recycling via endosomal pathway. In this study, to clarify whether the endosomal trafficking is required for CFTR maturation, we utilized a specific vacuolar H+-ATPase inhibitor, bafilomycin A1 (BafA1), which inhibits the protein trafficking from early endosome. Our data showed that low concentration of BafA1 (50 nM) decreased the expression of mature CFTR but induced the accumulation of immature CFTR in the juxta-nuclear region containing an early endosome marker. Pulse-chase analysis showed that BafA1 inhibited the maturation of CFTR, but it slightly stabilized immature CFTR. These results indicate that BafA1-sensitive pathway is required for CFTR maturation and emphasize that endosomal trafficking pathway might be involved in the maturation of CFTR.
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Affiliation(s)
- Tsukasa Okiyoneda
- Department of Molecular Medicine, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University, Kumamoto 862-0973, Japan
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Davidson H, McLachlan G, Wilson A, Boyd AC, Doherty A, MacGregor G, Davies L, Painter HA, Coles R, Hyde SC, Gill DR, Amaral MD, Collie DDS, Porteous DJ, Penque D. Human-specific cystic fibrosis transmembrane conductance regulator antibodies detect in vivo gene transfer to ovine airways. Am J Respir Cell Mol Biol 2006; 35:72-83. [PMID: 16498081 DOI: 10.1165/rcmb.2005-0377oc] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
A panel of 11 human cystic fibrosis transmembrane conductance regulator (hCFTR) antibodies were tested in ovine nasal, tracheal, and bronchial epithelial brushings. Two of these, G449 (polyclonal) and MATG1104 (monoclonal), recognized hCFTR but did not cross react with endogenous sheep CFTR. This specificity allows immunologic detection of hCFTR expressed in gene transfer studies in sheep against the background of endogenous ovine CFTR, thus enhancing the value of the sheep as a model animal in which to study CFTR gene transfer. Studies on mixed populations of human and sheep nasal epithelial cells showed that detection of hCFTR by these two antibodies was possible even at the lowest proportion of human cells (1:100). The hCFTR gene was delivered in vivo by local instillation using polyethylenimine-mediated gene transfer to the ventral surface of the ovine trachea and hCFTR mRNA and protein levels scored in a blinded fashion. Despite abundant hCFTR mRNA expression, the number of cells expressing hCFTR protein detectable by G449 was low (approximately 0.006-0.05%). Immunohistochemistry for hCFTR in animals treated by whole-lung aerosol demonstrated positive cells in sections of tracheal epithelium and in distal conducting airways. The strategic use of hCFTR-specific antibodies supports the utility of the normal sheep as a model for hCFTR gene transfer studies.
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Affiliation(s)
- Heather Davidson
- Medical Sciences (Medical Genetics), University of Edinburgh, Molecular Medicine Centre, Western General Hospital, Edinburgh EH4 2XU, United Kingdom.
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