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Rooj AK, Cormet-Boyaka E, Clark EB, Qadri YJ, Lee W, Boddu R, Agarwal A, Tambi R, Uddin M, Parpura V, Sorscher EJ, Fuller CM, Berdiev BK. Association of cystic fibrosis transmembrane conductance regulator with epithelial sodium channel subunits carrying Liddle's syndrome mutations. Am J Physiol Lung Cell Mol Physiol 2021; 321:L308-L320. [PMID: 34037494 DOI: 10.1152/ajplung.00298.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The association of the cystic fibrosis transmembrane conductance regulator (CFTR) and epithelial sodium channel (ENaC) in the pathophysiology of cystic fibrosis (CF) is controversial. Previously, we demonstrated a close physical association between wild-type (WT) CFTR and WT ENaC. We have also shown that the F508del CFTR fails to associate with ENaC unless the mutant protein is rescued pharmacologically or by low temperature. In this study, we present the evidence for a direct physical association between WT CFTR and ENaC subunits carrying Liddle's syndrome mutations. We show that all three ENaC subunits bearing Liddle's syndrome mutations (both point mutations and the complete truncation of the carboxy terminus), could be coimmunoprecipitated with WT CFTR. The biochemical studies were complemented by fluorescence lifetime imaging microscopy (FLIM), a distance-dependent approach that monitors protein-protein interactions between fluorescently labeled molecules. Our measurements revealed significantly increased fluorescence resonance energy transfer between CFTR and all tested ENaC combinations as compared with controls (ECFP and EYFP cotransfected cells). Our findings are consistent with the notion that CFTR and ENaC are within reach of each other even in the setting of Liddle's syndrome mutations, suggestive of a direct intermolecular interaction between these two proteins.
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Affiliation(s)
- Arun K Rooj
- Department of Cell, Developmental & Integrative Biology, The University of Alabama at Birmingham School of Medicine, Birmingham, Alabama
| | | | - Edlira B Clark
- Department of Cell, Developmental & Integrative Biology, The University of Alabama at Birmingham School of Medicine, Birmingham, Alabama
| | - Yawar J Qadri
- Department of Anesthesiology, The Emory University School of Medicine, Atlanta, Georgia
| | - William Lee
- Department of Neurobiology, The University of Alabama at Birmingham School of Medicine, Birmingham, Alabama
| | - Ravindra Boddu
- Department of Medicine, The University of Alabama at Birmingham School of Medicine, Birmingham, Alabama
| | - Anupam Agarwal
- Department of Medicine, The University of Alabama at Birmingham School of Medicine, Birmingham, Alabama
| | - Richa Tambi
- College of Medicine, Mohammed Bin Rashid University of Medicine and Health Sciences, Dubai, United Arab Emirates
| | - Mohammed Uddin
- College of Medicine, Mohammed Bin Rashid University of Medicine and Health Sciences, Dubai, United Arab Emirates
| | - Vladimir Parpura
- Department of Neurobiology, The University of Alabama at Birmingham School of Medicine, Birmingham, Alabama
| | - Eric J Sorscher
- Department of Pediatrics, The Emory University School of Medicine, Atlanta, Georgia
| | - Cathy M Fuller
- Department of Cell, Developmental & Integrative Biology, The University of Alabama at Birmingham School of Medicine, Birmingham, Alabama
| | - Bakhrom K Berdiev
- Department of Cell, Developmental & Integrative Biology, The University of Alabama at Birmingham School of Medicine, Birmingham, Alabama.,College of Medicine, Mohammed Bin Rashid University of Medicine and Health Sciences, Dubai, United Arab Emirates
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2
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Alzahrani AS, Alswailem M, Abbas BB, Qasem E, Alsagheir A, Al Shidhani A, Al Sinani A, Al Badi M, Al-Maqbali A, Al Shawi M, Albunyan A, Bin Nafisah A, Shi Y. A Unique Genotype of Pseudohypoaldosteronism Type 1b in a Highly Consanguineous Population. J Endocr Soc 2021; 5:bvab095. [PMID: 34258491 PMCID: PMC8272535 DOI: 10.1210/jendso/bvab095] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Context Pseudohypoaldosteronism (PHA) is a condition in which serum aldosterone level is normal or elevated but its action is deficient. Objective This study describes the molecular genetics of PHA 1b in the highly consanguineous population of 2 Arabian Gulf countries, Saudi Arabia and Oman. Methods This study enrolled 22 patients from 13 unrelated families (2 families with 5 patients from Oman and 11 families with 17 patients from Saudi Arabia). All of these patients had presented within the first 10 days of life with nausea and vomiting, hyponatremia, hyperkalemia, and hypotension. We isolated DNA from peripheral blood and PCR-sequenced all exons and exon-intron boundaries of SCNN1A and, if negative, SCNN1B and SCNN1G using the Dideoxy Chain termination method. Results We found a total of 8 mutations in 13 families as follows: 6 mutations in SCNN1A, 1 in SCNN1B, and 1 in SCNN1G. All of these mutations were novel except one. SCNN1A mutations were: c.1496A>G, p.Q499R (novel) in 1 patient; c.1453C>T, p.Q485X (novel) in 1 patient; c.1322_1322delA, p.N441Tfs*41 (novel) in 2 patients of 1 family; c.876 + 2 delGAGT (novel) in 3 patients of 1 family; c.203_204 delTC, p.I68Tfs*76 (a known mutation) in 8 patients of 5 families; and whole SCNN1A gene deletion (novel) in 2 patients of 2 families. In addition, a nonsense SCNN1B mutation c.1694C>A, p.S565X (novel) was found in 3 siblings from 1 Omani family, and an SCNN1G deletion mutation c.527_528 delCA, p.T176Rfs*9 (novel) in 2 siblings from another Omani family. Conclusion We characterized a unique genotype of PHA 1b with several novel gene structure-disrupting mutations in SCNN1A, SCNN1B, and SCNN1G in a highly consanguineous population.
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Affiliation(s)
- Ali S Alzahrani
- Department of Medicine, King Faisal Specialist Hospital & Research Centre, Riyadh 11211, Saudi Arabia.,Department of Molecular Oncology, King Faisal Specialist Hospital & Research Centre, Riyadh 11211, Saudi Arabia
| | - Meshael Alswailem
- Department of Molecular Oncology, King Faisal Specialist Hospital & Research Centre, Riyadh 11211, Saudi Arabia
| | - Bassam Bin Abbas
- Department of Pediatrics, King Faisal Specialist Hospital & Research Centre, Riyadh 11211, Saudi Arabia
| | - Ebtesam Qasem
- Department of Molecular Oncology, King Faisal Specialist Hospital & Research Centre, Riyadh 11211, Saudi Arabia
| | - Afaf Alsagheir
- Department of Pediatrics, King Faisal Specialist Hospital & Research Centre, Riyadh 11211, Saudi Arabia
| | - Azza Al Shidhani
- Department of Pediatrics, King Faisal Specialist Hospital & Research Centre, Riyadh 11211, Saudi Arabia
| | | | - Maryam Al Badi
- Department of Pediatrics, Royal Hospital, 111 Muscat, Oman
| | - Ali Al-Maqbali
- Department of Medicine, Royal Hospital 111, Muscat, Oman
| | - Manal Al Shawi
- Maternity and Children Hospital, Alhasa 36361, Saudi Arabia
| | | | - Abdulghani Bin Nafisah
- Department of Molecular Oncology, King Faisal Specialist Hospital & Research Centre, Riyadh 11211, Saudi Arabia
| | - Yufei Shi
- Center for Genomic Medicine, King Faisal Specialist Hospital & Research Centre, Riyadh 11211, Saudi Arabia
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3
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Molecular Interactions between Two LMP2A PY Motifs of EBV and WW Domains of E3 Ubiquitin Ligase AIP4. Life (Basel) 2021; 11:life11050379. [PMID: 33922228 PMCID: PMC8190631 DOI: 10.3390/life11050379] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 04/20/2021] [Accepted: 04/21/2021] [Indexed: 12/15/2022] Open
Abstract
Interactions involving Epstein–Barr virus (EBV) LMP2A and Nedd4 family E3 ubiquitin–protein ligases promote the ubiquitination of LMP2A-associated proteins, which results in the perturbation of normal B-cell signaling. Here, we solved the solution structure of the WW2 domain of hAIP4 and investigated the binding mode involving the N-terminal domain of LMP2A and the WW2 domain. The WW2 domain presented a conserved WW domain scaffold with a three-stranded anti-parallel β-sheet and bound two PY motifs via different binding mechanisms. Our NMR titration and ITC data demonstrated that the PY motifs of LMP2A can recognize and interact weakly with the XP groove of the WW2 domain (residues located around the third β-strand), and then residues between two PY motifs optimize the binding by interacting with the loop 1 region of the WW2 domain. In particular, the residue Val15 in the hairpin loop region between β1 and β2 of the WW2 domain exhibited unique changes depending on the terminal residues of the PY motif. This result suggested that the hairpin loop is responsible for additional interactions outside the XP groove, and this hypothesis was confirmed in a deuterium exchange experiment. These weak but wide interactions can stabilize the complex formed between the PY and WW domains.
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Huang S, Hsu L, Chang N. Functional role of WW domain-containing proteins in tumor biology and diseases: Insight into the role in ubiquitin-proteasome system. FASEB Bioadv 2020; 2:234-253. [PMID: 32259050 PMCID: PMC7133736 DOI: 10.1096/fba.2019-00060] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 07/23/2019] [Accepted: 01/31/2020] [Indexed: 01/10/2023] Open
Abstract
The ubiquitin-proteasome system (UPS) governs the protein degradation process and balances proteostasis and cellular homeostasis. It is a well-controlled mechanism, in which removal of the damaged or excessive proteins is essential in driving signal pathways for cell survival or death. Accumulation of damaged proteins and failure in removal may contribute to disease initiation such as in cancers and neurodegenerative diseases. In this notion, specific protein-protein interaction is essential for the recognition of targeted proteins in UPS. WW domain plays an indispensable role in the protein-protein interactions during signaling. Among the 51 WW domain-containing proteins in the human proteomics, near one-quarter of them are involved in the UPS, suggesting that WW domains are crucial modules for driving the protein-protein binding and subsequent ubiquitination and degradation. In this review, we detail a broad spectrum of WW domains in protein-protein recognition, signal transduction, and relevance to diseases. New perspectives in dissecting the molecular interactions are provided.
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Affiliation(s)
- Shenq‐Shyang Huang
- Graduate Program of Biotechnology in MedicineInstitute of Molecular and Cellular BiologyNational Tsing Hua UniversityHsinchuTaiwan, ROC
| | - Li‐Jin Hsu
- Department of Medical Laboratory Science and BiotechnologyNational Cheng Kung University College of MedicineTainanTaiwan, ROC
| | - Nan‐Shan Chang
- Institute of Molecular MedicineNational Cheng Kung University College of MedicineTainanTaiwan, ROC
- Department of NeurochemistryNew York State Institute for Basic Research in Developmental DisabilitiesStaten IslandNYUSA
- Graduate Institute of Biomedical SciencesCollege of MedicineChina Medical UniversityTaichungTaiwan, ROC
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Abstract
Liddle syndrome is an inherited form of low-renin hypertension, transmitted with an autosomal dominant pattern. The molecular basis of Liddle syndrome resides in germline mutations of the SCNN1A, SCNN1B and SCNN1G genes, encoding the α, β, and γ-subunits of the epithelial Na+ channel (ENaC), respectively. To date, 31 different causative mutations have been reported in 72 families from four continents. The majority of the substitutions cause an increased expression of the channel at the distal nephron apical membrane, with subsequent enhanced renal sodium reabsorption. The most common clinical presentation of the disease is early onset hypertension, hypokalemia, metabolic alkalosis, suppressed plasma renin activity and low plasma aldosterone. Consequently, treatment of Liddle syndrome is based on the administration of ENaC blockers, amiloride and triamterene. Herein, we discuss the genetic basis, clinical presentation, diagnosis and treatment of Liddle syndrome. Finally, we report a new case in an Italian family, caused by a SCNN1B p.Pro618Leu substitution.
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Hamacher J, Hadizamani Y, Borgmann M, Mohaupt M, Männel DN, Moehrlen U, Lucas R, Stammberger U. Cytokine-Ion Channel Interactions in Pulmonary Inflammation. Front Immunol 2018; 8:1644. [PMID: 29354115 PMCID: PMC5758508 DOI: 10.3389/fimmu.2017.01644] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Accepted: 11/10/2017] [Indexed: 12/12/2022] Open
Abstract
The lungs conceptually represent a sponge that is interposed in series in the bodies’ systemic circulation to take up oxygen and eliminate carbon dioxide. As such, it matches the huge surface areas of the alveolar epithelium to the pulmonary blood capillaries. The lung’s constant exposure to the exterior necessitates a competent immune system, as evidenced by the association of clinical immunodeficiencies with pulmonary infections. From the in utero to the postnatal and adult situation, there is an inherent vital need to manage alveolar fluid reabsorption, be it postnatally, or in case of hydrostatic or permeability edema. Whereas a wealth of literature exists on the physiological basis of fluid and solute reabsorption by ion channels and water pores, only sparse knowledge is available so far on pathological situations, such as in microbial infection, acute lung injury or acute respiratory distress syndrome, and in the pulmonary reimplantation response in transplanted lungs. The aim of this review is to discuss alveolar liquid clearance in a selection of lung injury models, thereby especially focusing on cytokines and mediators that modulate ion channels. Inflammation is characterized by complex and probably time-dependent co-signaling, interactions between the involved cell types, as well as by cell demise and barrier dysfunction, which may not uniquely determine a clinical picture. This review, therefore, aims to give integrative thoughts and wants to foster the unraveling of unmet needs in future research.
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Affiliation(s)
- Jürg Hamacher
- Internal Medicine and Pneumology, Lindenhofspital, Bern, Switzerland.,Internal Medicine V - Pneumology, Allergology, Respiratory and Environmental Medicine, Faculty of Medicine, Saarland University, Saarbrücken, Germany.,Lungen- und Atmungsstiftung Bern, Bern, Switzerland
| | - Yalda Hadizamani
- Internal Medicine and Pneumology, Lindenhofspital, Bern, Switzerland.,Lungen- und Atmungsstiftung Bern, Bern, Switzerland
| | - Michèle Borgmann
- Internal Medicine and Pneumology, Lindenhofspital, Bern, Switzerland.,Lungen- und Atmungsstiftung Bern, Bern, Switzerland
| | - Markus Mohaupt
- Internal Medicine, Sonnenhofspital Bern, Bern, Switzerland
| | | | - Ueli Moehrlen
- Paediatric Visceral Surgery, Universitäts-Kinderspital Zürich, Zürich, Switzerland
| | - Rudolf Lucas
- Department of Pharmacology and Toxicology, Vascular Biology Center, Medical College of Georgia, Augusta, GA, United States
| | - Uz Stammberger
- Lungen- und Atmungsstiftung Bern, Bern, Switzerland.,Novartis Institutes for Biomedical Research, Translational Clinical Oncology, Novartis Pharma AG, Basel, Switzerland
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7
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Pagani L, Diekmann Y, Sazzini M, De Fanti S, Rondinelli M, Farnetti E, Casali B, Caretto A, Novara F, Zuffardi O, Garagnani P, Mantero F, Thomas MG, Luiselli D, Rossi E. Three Reportedly Unrelated Families With Liddle Syndrome Inherited From a Common Ancestor. Hypertension 2017; 71:273-279. [PMID: 29229744 DOI: 10.1161/hypertensionaha.117.10491] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 10/31/2017] [Accepted: 11/14/2017] [Indexed: 12/31/2022]
Abstract
Liddle syndrome is considered a rare Mendelian hypertension. We have previously described 3 reportedly unrelated families, native of an Italian area around the Strait of Messina, carrying the same mutation (βP617L) of the epithelial sodium channel. The aims of our study were (1) to evaluate whether a close genomic relationship exists between the 3 families through the analysis of mitochondrial DNA and Y chromosome; and (2) to quantify the genomic relatedness between the patients with Liddle syndrome belonging to the 3 families and assess the hypothesis of a mutation shared through identity by descent. HVRI (the hypervariable region I) of the mitochondrial DNA genome and the Y chromosome short tandem repeats profiles were analyzed in individuals of the 3 families. Genotyping 542 585 genome-wide single nucleotide polymorphisms was performed in all the patients with Liddle syndrome of the 3 families and some of their relatives. A panel of 780 healthy Italian adult samples typed for the same set of markers was used as controls. espite different lineages between the 3 families based on the analysis of mitochondrial DNA and Y chromosome, the 3 probands and their 6 affected relatives share the same ≈5 Mbp long haplotype which encompasses the mutant allele. Using an approach based on coalescent theory, we estimate that the 3 families inherited the mutant allele from a common ancestor ≈13 generations ago and that such an ancestor may have left ≈20 carriers alive today. The prevalence of Liddle syndrome in the region of origin of the 3 families may be much higher than that estimated worldwide.
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Affiliation(s)
- Luca Pagani
- From the Department of Biology (L.P.) and Endocrinology Unit, Department of Medicine (F.M.), University of Padova, Italy; Estonian Biocentre, Tartu (L.P.); Research Department of Genetics, Evolution and Environment, University College London, United Kingdom (Y.D., M.G.T.); Department of Biological Geological and Environmental Sciences (M.S., S.D.F., D.L.) and Department of Experimental, Diagnostic and Specialty Medicine (P.G.), University of Bologna, Italy; IRCCS Centro Cardiologico Monzino, Milano, Italy (M.R.); Department of Oncology and Advanced Technologies, Laboratory of Molecular Biology (E.F., B.C.) and Department of Internal Medicine (E.R.), IRCCS Santa Maria Nuova Hospital, Reggio Emilia, Italy; Department of Endocrinology and Metabolic Diseases, San Raffaele Scientific Institute, Milano, Italy (A.C.); and Department of Molecular Medicine, University of Pavia, Italy (F.N., O.Z.)
| | - Yoan Diekmann
- From the Department of Biology (L.P.) and Endocrinology Unit, Department of Medicine (F.M.), University of Padova, Italy; Estonian Biocentre, Tartu (L.P.); Research Department of Genetics, Evolution and Environment, University College London, United Kingdom (Y.D., M.G.T.); Department of Biological Geological and Environmental Sciences (M.S., S.D.F., D.L.) and Department of Experimental, Diagnostic and Specialty Medicine (P.G.), University of Bologna, Italy; IRCCS Centro Cardiologico Monzino, Milano, Italy (M.R.); Department of Oncology and Advanced Technologies, Laboratory of Molecular Biology (E.F., B.C.) and Department of Internal Medicine (E.R.), IRCCS Santa Maria Nuova Hospital, Reggio Emilia, Italy; Department of Endocrinology and Metabolic Diseases, San Raffaele Scientific Institute, Milano, Italy (A.C.); and Department of Molecular Medicine, University of Pavia, Italy (F.N., O.Z.)
| | - Marco Sazzini
- From the Department of Biology (L.P.) and Endocrinology Unit, Department of Medicine (F.M.), University of Padova, Italy; Estonian Biocentre, Tartu (L.P.); Research Department of Genetics, Evolution and Environment, University College London, United Kingdom (Y.D., M.G.T.); Department of Biological Geological and Environmental Sciences (M.S., S.D.F., D.L.) and Department of Experimental, Diagnostic and Specialty Medicine (P.G.), University of Bologna, Italy; IRCCS Centro Cardiologico Monzino, Milano, Italy (M.R.); Department of Oncology and Advanced Technologies, Laboratory of Molecular Biology (E.F., B.C.) and Department of Internal Medicine (E.R.), IRCCS Santa Maria Nuova Hospital, Reggio Emilia, Italy; Department of Endocrinology and Metabolic Diseases, San Raffaele Scientific Institute, Milano, Italy (A.C.); and Department of Molecular Medicine, University of Pavia, Italy (F.N., O.Z.)
| | - Sara De Fanti
- From the Department of Biology (L.P.) and Endocrinology Unit, Department of Medicine (F.M.), University of Padova, Italy; Estonian Biocentre, Tartu (L.P.); Research Department of Genetics, Evolution and Environment, University College London, United Kingdom (Y.D., M.G.T.); Department of Biological Geological and Environmental Sciences (M.S., S.D.F., D.L.) and Department of Experimental, Diagnostic and Specialty Medicine (P.G.), University of Bologna, Italy; IRCCS Centro Cardiologico Monzino, Milano, Italy (M.R.); Department of Oncology and Advanced Technologies, Laboratory of Molecular Biology (E.F., B.C.) and Department of Internal Medicine (E.R.), IRCCS Santa Maria Nuova Hospital, Reggio Emilia, Italy; Department of Endocrinology and Metabolic Diseases, San Raffaele Scientific Institute, Milano, Italy (A.C.); and Department of Molecular Medicine, University of Pavia, Italy (F.N., O.Z.)
| | - Maurizio Rondinelli
- From the Department of Biology (L.P.) and Endocrinology Unit, Department of Medicine (F.M.), University of Padova, Italy; Estonian Biocentre, Tartu (L.P.); Research Department of Genetics, Evolution and Environment, University College London, United Kingdom (Y.D., M.G.T.); Department of Biological Geological and Environmental Sciences (M.S., S.D.F., D.L.) and Department of Experimental, Diagnostic and Specialty Medicine (P.G.), University of Bologna, Italy; IRCCS Centro Cardiologico Monzino, Milano, Italy (M.R.); Department of Oncology and Advanced Technologies, Laboratory of Molecular Biology (E.F., B.C.) and Department of Internal Medicine (E.R.), IRCCS Santa Maria Nuova Hospital, Reggio Emilia, Italy; Department of Endocrinology and Metabolic Diseases, San Raffaele Scientific Institute, Milano, Italy (A.C.); and Department of Molecular Medicine, University of Pavia, Italy (F.N., O.Z.)
| | - Enrico Farnetti
- From the Department of Biology (L.P.) and Endocrinology Unit, Department of Medicine (F.M.), University of Padova, Italy; Estonian Biocentre, Tartu (L.P.); Research Department of Genetics, Evolution and Environment, University College London, United Kingdom (Y.D., M.G.T.); Department of Biological Geological and Environmental Sciences (M.S., S.D.F., D.L.) and Department of Experimental, Diagnostic and Specialty Medicine (P.G.), University of Bologna, Italy; IRCCS Centro Cardiologico Monzino, Milano, Italy (M.R.); Department of Oncology and Advanced Technologies, Laboratory of Molecular Biology (E.F., B.C.) and Department of Internal Medicine (E.R.), IRCCS Santa Maria Nuova Hospital, Reggio Emilia, Italy; Department of Endocrinology and Metabolic Diseases, San Raffaele Scientific Institute, Milano, Italy (A.C.); and Department of Molecular Medicine, University of Pavia, Italy (F.N., O.Z.)
| | - Bruno Casali
- From the Department of Biology (L.P.) and Endocrinology Unit, Department of Medicine (F.M.), University of Padova, Italy; Estonian Biocentre, Tartu (L.P.); Research Department of Genetics, Evolution and Environment, University College London, United Kingdom (Y.D., M.G.T.); Department of Biological Geological and Environmental Sciences (M.S., S.D.F., D.L.) and Department of Experimental, Diagnostic and Specialty Medicine (P.G.), University of Bologna, Italy; IRCCS Centro Cardiologico Monzino, Milano, Italy (M.R.); Department of Oncology and Advanced Technologies, Laboratory of Molecular Biology (E.F., B.C.) and Department of Internal Medicine (E.R.), IRCCS Santa Maria Nuova Hospital, Reggio Emilia, Italy; Department of Endocrinology and Metabolic Diseases, San Raffaele Scientific Institute, Milano, Italy (A.C.); and Department of Molecular Medicine, University of Pavia, Italy (F.N., O.Z.)
| | - Amelia Caretto
- From the Department of Biology (L.P.) and Endocrinology Unit, Department of Medicine (F.M.), University of Padova, Italy; Estonian Biocentre, Tartu (L.P.); Research Department of Genetics, Evolution and Environment, University College London, United Kingdom (Y.D., M.G.T.); Department of Biological Geological and Environmental Sciences (M.S., S.D.F., D.L.) and Department of Experimental, Diagnostic and Specialty Medicine (P.G.), University of Bologna, Italy; IRCCS Centro Cardiologico Monzino, Milano, Italy (M.R.); Department of Oncology and Advanced Technologies, Laboratory of Molecular Biology (E.F., B.C.) and Department of Internal Medicine (E.R.), IRCCS Santa Maria Nuova Hospital, Reggio Emilia, Italy; Department of Endocrinology and Metabolic Diseases, San Raffaele Scientific Institute, Milano, Italy (A.C.); and Department of Molecular Medicine, University of Pavia, Italy (F.N., O.Z.)
| | - Francesca Novara
- From the Department of Biology (L.P.) and Endocrinology Unit, Department of Medicine (F.M.), University of Padova, Italy; Estonian Biocentre, Tartu (L.P.); Research Department of Genetics, Evolution and Environment, University College London, United Kingdom (Y.D., M.G.T.); Department of Biological Geological and Environmental Sciences (M.S., S.D.F., D.L.) and Department of Experimental, Diagnostic and Specialty Medicine (P.G.), University of Bologna, Italy; IRCCS Centro Cardiologico Monzino, Milano, Italy (M.R.); Department of Oncology and Advanced Technologies, Laboratory of Molecular Biology (E.F., B.C.) and Department of Internal Medicine (E.R.), IRCCS Santa Maria Nuova Hospital, Reggio Emilia, Italy; Department of Endocrinology and Metabolic Diseases, San Raffaele Scientific Institute, Milano, Italy (A.C.); and Department of Molecular Medicine, University of Pavia, Italy (F.N., O.Z.)
| | - Orsetta Zuffardi
- From the Department of Biology (L.P.) and Endocrinology Unit, Department of Medicine (F.M.), University of Padova, Italy; Estonian Biocentre, Tartu (L.P.); Research Department of Genetics, Evolution and Environment, University College London, United Kingdom (Y.D., M.G.T.); Department of Biological Geological and Environmental Sciences (M.S., S.D.F., D.L.) and Department of Experimental, Diagnostic and Specialty Medicine (P.G.), University of Bologna, Italy; IRCCS Centro Cardiologico Monzino, Milano, Italy (M.R.); Department of Oncology and Advanced Technologies, Laboratory of Molecular Biology (E.F., B.C.) and Department of Internal Medicine (E.R.), IRCCS Santa Maria Nuova Hospital, Reggio Emilia, Italy; Department of Endocrinology and Metabolic Diseases, San Raffaele Scientific Institute, Milano, Italy (A.C.); and Department of Molecular Medicine, University of Pavia, Italy (F.N., O.Z.)
| | - Paolo Garagnani
- From the Department of Biology (L.P.) and Endocrinology Unit, Department of Medicine (F.M.), University of Padova, Italy; Estonian Biocentre, Tartu (L.P.); Research Department of Genetics, Evolution and Environment, University College London, United Kingdom (Y.D., M.G.T.); Department of Biological Geological and Environmental Sciences (M.S., S.D.F., D.L.) and Department of Experimental, Diagnostic and Specialty Medicine (P.G.), University of Bologna, Italy; IRCCS Centro Cardiologico Monzino, Milano, Italy (M.R.); Department of Oncology and Advanced Technologies, Laboratory of Molecular Biology (E.F., B.C.) and Department of Internal Medicine (E.R.), IRCCS Santa Maria Nuova Hospital, Reggio Emilia, Italy; Department of Endocrinology and Metabolic Diseases, San Raffaele Scientific Institute, Milano, Italy (A.C.); and Department of Molecular Medicine, University of Pavia, Italy (F.N., O.Z.)
| | - Franco Mantero
- From the Department of Biology (L.P.) and Endocrinology Unit, Department of Medicine (F.M.), University of Padova, Italy; Estonian Biocentre, Tartu (L.P.); Research Department of Genetics, Evolution and Environment, University College London, United Kingdom (Y.D., M.G.T.); Department of Biological Geological and Environmental Sciences (M.S., S.D.F., D.L.) and Department of Experimental, Diagnostic and Specialty Medicine (P.G.), University of Bologna, Italy; IRCCS Centro Cardiologico Monzino, Milano, Italy (M.R.); Department of Oncology and Advanced Technologies, Laboratory of Molecular Biology (E.F., B.C.) and Department of Internal Medicine (E.R.), IRCCS Santa Maria Nuova Hospital, Reggio Emilia, Italy; Department of Endocrinology and Metabolic Diseases, San Raffaele Scientific Institute, Milano, Italy (A.C.); and Department of Molecular Medicine, University of Pavia, Italy (F.N., O.Z.)
| | - Mark G Thomas
- From the Department of Biology (L.P.) and Endocrinology Unit, Department of Medicine (F.M.), University of Padova, Italy; Estonian Biocentre, Tartu (L.P.); Research Department of Genetics, Evolution and Environment, University College London, United Kingdom (Y.D., M.G.T.); Department of Biological Geological and Environmental Sciences (M.S., S.D.F., D.L.) and Department of Experimental, Diagnostic and Specialty Medicine (P.G.), University of Bologna, Italy; IRCCS Centro Cardiologico Monzino, Milano, Italy (M.R.); Department of Oncology and Advanced Technologies, Laboratory of Molecular Biology (E.F., B.C.) and Department of Internal Medicine (E.R.), IRCCS Santa Maria Nuova Hospital, Reggio Emilia, Italy; Department of Endocrinology and Metabolic Diseases, San Raffaele Scientific Institute, Milano, Italy (A.C.); and Department of Molecular Medicine, University of Pavia, Italy (F.N., O.Z.)
| | - Donata Luiselli
- From the Department of Biology (L.P.) and Endocrinology Unit, Department of Medicine (F.M.), University of Padova, Italy; Estonian Biocentre, Tartu (L.P.); Research Department of Genetics, Evolution and Environment, University College London, United Kingdom (Y.D., M.G.T.); Department of Biological Geological and Environmental Sciences (M.S., S.D.F., D.L.) and Department of Experimental, Diagnostic and Specialty Medicine (P.G.), University of Bologna, Italy; IRCCS Centro Cardiologico Monzino, Milano, Italy (M.R.); Department of Oncology and Advanced Technologies, Laboratory of Molecular Biology (E.F., B.C.) and Department of Internal Medicine (E.R.), IRCCS Santa Maria Nuova Hospital, Reggio Emilia, Italy; Department of Endocrinology and Metabolic Diseases, San Raffaele Scientific Institute, Milano, Italy (A.C.); and Department of Molecular Medicine, University of Pavia, Italy (F.N., O.Z.)
| | - Ermanno Rossi
- From the Department of Biology (L.P.) and Endocrinology Unit, Department of Medicine (F.M.), University of Padova, Italy; Estonian Biocentre, Tartu (L.P.); Research Department of Genetics, Evolution and Environment, University College London, United Kingdom (Y.D., M.G.T.); Department of Biological Geological and Environmental Sciences (M.S., S.D.F., D.L.) and Department of Experimental, Diagnostic and Specialty Medicine (P.G.), University of Bologna, Italy; IRCCS Centro Cardiologico Monzino, Milano, Italy (M.R.); Department of Oncology and Advanced Technologies, Laboratory of Molecular Biology (E.F., B.C.) and Department of Internal Medicine (E.R.), IRCCS Santa Maria Nuova Hospital, Reggio Emilia, Italy; Department of Endocrinology and Metabolic Diseases, San Raffaele Scientific Institute, Milano, Italy (A.C.); and Department of Molecular Medicine, University of Pavia, Italy (F.N., O.Z.).
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8
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Chen L, Higgins PJ, Zhang W. Development and Diseases of the Collecting Duct System. Results Probl Cell Differ 2017; 60:165-203. [PMID: 28409346 DOI: 10.1007/978-3-319-51436-9_7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The collecting duct of the mammalian kidney is important for the regulation of extracellular volume, osmolarity, and pH. There are two major structurally and functionally distinct cell types: principal cells and intercalated cells. The former regulates Na+ and water homeostasis, while the latter participates in acid-base homeostasis. In vivo lineage tracing using Cre recombinase or its derivatives such as CreGFP and CreERT2 is a powerful new technique to identify stem/progenitor cells in their native environment and to decipher the origins of the tissue that they give rise to. Recent studies using this technique in mice have revealed multiple renal progenitor cell populations that differentiate into various nephron segments and collecting duct. In particular, emerging evidence suggests that like principal cells, most of intercalated cells originate from the progenitor cells expressing water channel Aquaporin 2. Mutations or malfunctions of the channels, pumps, and transporters expressed in the collecting duct system cause various human diseases. For example, gain-of-function mutations in ENaC cause Liddle's syndrome, while loss-of-function mutations in ENaC lead to Pseudohypoaldosteronism type 1. Mutations in either AE1 or V-ATPase B1 result in distal renal tubular acidosis. Patients with disrupted AQP2 or AVPR2 develop nephrogenic diabetes insipidus. A better understanding of the function and development of the collecting duct system may facilitate the discovery of new therapeutic strategies for treating kidney disease.
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Affiliation(s)
- Lihe Chen
- Epithelial Systems Biology Laboratory, Systems Biology Center, NHLBI, Bethesda, MD, 20892-1603, USA
| | - Paul J Higgins
- Department of Regenerative and Cancer Cell Biology, Albany Medical College, MC-165, 47 New Scotland Avenue, Albany, NY, 12208, USA
| | - Wenzheng Zhang
- Department of Regenerative and Cancer Cell Biology, Albany Medical College, MC-165, 47 New Scotland Avenue, Albany, NY, 12208, USA.
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9
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Willam A, Aufy M, Tzotzos S, Evanzin H, Chytracek S, Geppert S, Fischer B, Fischer H, Pietschmann H, Czikora I, Lucas R, Lemmens-Gruber R, Shabbir W. Restoration of Epithelial Sodium Channel Function by Synthetic Peptides in Pseudohypoaldosteronism Type 1B Mutants. Front Pharmacol 2017; 8:85. [PMID: 28286482 PMCID: PMC5323398 DOI: 10.3389/fphar.2017.00085] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Accepted: 02/09/2017] [Indexed: 12/20/2022] Open
Abstract
The synthetically produced cyclic peptides solnatide (a.k.a. TIP or AP301) and its congener AP318, whose molecular structures mimic the lectin-like domain of human tumor necrosis factor (TNF), have been shown to activate the epithelial sodium channel (ENaC) in various cell- and animal-based studies. Loss-of-ENaC-function leads to a rare, life-threatening, salt-wasting syndrome, pseudohypoaldosteronism type 1B (PHA1B), which presents with failure to thrive, dehydration, low blood pressure, anorexia and vomiting; hyperkalemia, hyponatremia and metabolic acidosis suggest hypoaldosteronism, but plasma aldosterone and renin activity are high. The aim of the present study was to investigate whether the ENaC-activating effect of solnatide and AP318 could rescue loss-of-function phenotype of ENaC carrying mutations at conserved amino acid positions observed to cause PHA1B. The macroscopic Na+ current of all investigated mutants was decreased compared to wild type ENaC when measured in whole-cell patch clamp experiments, and a great variation in the membrane abundance of different mutant ENaCs was observed with Western blotting experiments. However, whatever mechanism leads to loss-of-function of the studied ENaC mutations, the synthetic peptides solnatide and AP318 could restore ENaC function up to or even higher than current levels of wild type ENaC. As therapy of PHA1B is only symptomatic so far, the peptides solnatide and AP318, which directly target ENaC, are promising candidates for the treatment of the channelopathy-caused disease PHA1B.
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Affiliation(s)
- Anita Willam
- Department of Pharmacology and Toxicology, University of Vienna Vienna, Austria
| | - Mohammed Aufy
- Department of Pharmacology and Toxicology, University of Vienna Vienna, Austria
| | | | - Heinrich Evanzin
- Department of Pharmacology and Toxicology, University of Vienna Vienna, Austria
| | - Sabine Chytracek
- Department of Pharmacology and Toxicology, University of Vienna Vienna, Austria
| | - Sabrina Geppert
- Department of Pharmacology and Toxicology, University of Vienna Vienna, Austria
| | | | | | | | - Istvan Czikora
- Vascular Biology Center, Medical College of Georgia, Augusta University Augusta, GA, USA
| | - Rudolf Lucas
- Vascular Biology Center, Medical College of Georgia, Augusta University Augusta, GA, USA
| | - Rosa Lemmens-Gruber
- Department of Pharmacology and Toxicology, University of Vienna Vienna, Austria
| | - Waheed Shabbir
- Department of Pharmacology and Toxicology, University of ViennaVienna, Austria; APEPTICO GmbHVienna, Austria
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10
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Meng G, Dai F, Tong X, Li N, Ding X, Song J, Lu C. Genome-wide analysis of the WW domain-containing protein genes in silkworm and their expansion in eukaryotes. Mol Genet Genomics 2014; 290:807-24. [PMID: 25424044 DOI: 10.1007/s00438-014-0958-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Accepted: 11/12/2014] [Indexed: 11/26/2022]
Abstract
WW domains are protein modules that mediate protein-protein interactions through recognition of proline-rich peptide motifs and phosphorylated serine/threonine-proline sites. WW domains are found in many different structural and signaling proteins that are involved in a variety of cellular processes. WW domain-containing proteins (WWCPs) and complexes have been implicated in major human diseases including cancer as well as in major signaling cascades such as the Hippo tumor suppressor pathway, making them targets for new diagnostics and therapeutics. There are a number of reports about the WWCPs in different species, but systematic analysis of the WWCP genes and its ligands is still lacking in silkworm and the other organisms. In this study, WWCP genes and PY motif-containing proteins have been identified and analyzed in 56 species including silkworm. Whole-genome screening of B. mori identified thirty-three proteins with thirty-nine WW domains located on thirteen chromosomes. In the 39 silkworm WW domains, 15 domains belong to the Group I WW domain; 14 domains were in Group II/III, 9 domains derived from 8 silkworm WWCPs could not be classified into any group, and Group IV contains only one WW domain. Based on gene annotation, silkworm WWCP genes have functions in multi-biology processes. A detailed list of WWCPs from the other 55 species was sorted in this work. In 14,623 silkworm predicted proteins, nearly 18 % contained PY motif, nearly 30 % contained various motifs totally that could be recognized by WW domains. Gene Ontology and KEGG analysis revealed that dozens of WW domain-binding proteins are involved in Wnt, Hedgehog, Notch, mTOR, EGF and Jak-STAT signaling pathway. Tissue expression patterns of WWCP genes and potential WWCP-binding protein genes on the third day of the fifth instar (L5D3) were examined by microarray analysis. Tissue expression profile analysis found that several WWCP genes and poly-proline or PY motif-containing protein genes took tissue- or gender-dependent expression manner in silkworms. We further analyzed WWCPs and PY motif-containing proteins in representative organisms of invertebrates and vertebrates. The results showed that there are no less than 16 and up to 29 WWCPs in insects, the average is 22. The number of WW domains in insects is no less than 19, and up to 47, the average is 36. In vertebrates, excluding the Hydrobiontes, the number of WWCPs is no less than 34 and up to 49, the average is 43. The number of WW domains in vertebrates is no less than 56 and up to 85, the average is 73. Phylogenetic analysis revealed that most homologous genes of the WWCP subfamily in vertebrates were duplicated during evolution and functions diverged. Nearly 1,000 PY motif-containing protein genes were found in insect genomes and nearly 2,000 genes in vertebrates. The different distributions of WWCP genes and PY motif-containing protein genes in different species revealed a possible positive correlation with organism complexity. In conclusion, this comprehensive bio-information analysis of WWCPs and its binding ligands would provide rich fundamental knowledge and useful information for further exploration of the function of the WW domain-containing proteins not only in silkworm, but also in other species.
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Affiliation(s)
- Gang Meng
- State Key Laboratory of Silkworm Genome Biology, Key Laboratory for Sericulture Functional Genomics and Biotechnology of Agricultural Ministry, Southwest University, Chongqing, 400716, China,
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11
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Gong L, Chen J, Shao L, Song W, Hui R, Wang Y. Phenotype-genotype analysis in two Chinese families with Liddle syndrome. Mol Biol Rep 2014; 41:1569-75. [PMID: 24474657 DOI: 10.1007/s11033-013-3003-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Accepted: 12/30/2013] [Indexed: 10/25/2022]
Abstract
The families with Liddle syndrome show marked phenotypic variation in blood pressure, serum potassium and other clinical manifestations. Here we analyzed the correlation of genotype-phenotype in two Chinese families with Liddle syndrome. The sequence of C-terminus of SCNN1B and SCNN1G were screened in the two families with likely Liddle syndrome. In addition to hypertension and hypokalemia, one of the two pedigrees had sudden death in their family members, so the exons of 428 reported genes-related to cardiovascular diseases were screened as well in the family. A heterozygous βR566X nonsense mutation was found in the proband-1 in the first pedigree, and the proband's sister and father. They showed mild phenotype with hypertension under control. In contrast, two of the four previous studies report that the mutation causes severe phenotype. A heterozygous βR597PfrX607 frameshift mutation was identified in the proband-2 in the second pedigree, showing malignant phenotype including resistant hypertension, hypokalemia, higher PRA and plasma angiotensin II levels. Both the proband-2 and the proband-2's father had sudden death in their twenties, but no meaningful mutations were found by screening of the exons in 428 cardiovascular disease-related genes. However, the same mutation has been related to moderate phenotype in previous studies. Our results confirmed that the phenotypes of Liddle syndrome are varied significantly even with the same mutation. The mechanisms why the same mutation causes very different phenotype need to be explored because intervention of these modifiers may change the disease course and prognosis accordingly.
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Affiliation(s)
- Ling Gong
- State Key Laboratory of Cardiovascular Disease, Sino-German Laboratory for Molecular Medicine, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, 167 Beilishi Road, Beijing, 100037, China
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12
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Zaydman MA, Silva JR, Cui J. Ion channel associated diseases: overview of molecular mechanisms. Chem Rev 2012; 112:6319-33. [PMID: 23151230 DOI: 10.1021/cr300360k] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Mark A Zaydman
- Department of Biomedical Engineering, Washington University, Saint Louis, Missouri 63130, United States
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13
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Bogdanović R, Kuburović V, Stajić N, Mughal SS, Hilger A, Ninić S, Prijić S, Ludwig M. Liddle syndrome in a Serbian family and literature review of underlying mutations. Eur J Pediatr 2012; 171:471-8. [PMID: 21956615 DOI: 10.1007/s00431-011-1581-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2011] [Accepted: 09/08/2011] [Indexed: 12/13/2022]
Abstract
UNLABELLED Severe and reproducible low-renin hypertension responsive to salt restriction and amiloride-thiazide therapy in a 13-year-old otherwise asymptomatic boy suggested Liddle syndrome. This assumption was strengthened by a positive family history of hypertension poorly responsive to conventional treatment or sudden deaths under 40 years of age in four generations. DNA analysis of the beta and gamma subunits of the epithelial sodium channel revealed a heterozygous mutation c.C1852T (p.Pro618Ser) in the SCNN1B gene in the patient and in both his hypertensive mother and uncle. A PubMed search revealed 21 different disease-causing mutations reported to date, all but two clustering in the cytoplasmic C-terminal regions of either beta (16 mutations) or gamma (5) subunit, leading to a three- to eightfold increase in the amiloride-sensitive sodium current. Inter- and intrafamilial variability in both hypertension and hypokalemia were disclosed, which may not be obligatory among the subjects carrying a Liddle mutation. CONCLUSION Liddle syndrome should be considered as a cause of hypertension in children or adolescents particularly with suppressed renin activity. Early diagnosis and appropriately tailored treatment avoid complications of long-term unrecognized or inappropriately managed hypertension.
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14
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Abstract
The epithelial Na(+) channel (ENaC) and acid-sensitive ion channel (ASIC) branches of the ENaC/degenerin superfamily of cation channels have drawn increasing attention as potential therapeutic targets in a variety of diseases and conditions. Originally thought to be solely expressed in fluid absorptive epithelia and in neurons, it has become apparent that members of this family exhibit nearly ubiquitous expression. Therapeutic opportunities range from hypertension, due to the role of ENaC in maintaining whole body salt and water homeostasis, to anxiety disorders and pain associated with ASIC activity. As a physiologist intrigued by the fundamental mechanics of salt and water transport, it was natural that Dale Benos, to whom this series of reviews is dedicated, should have been at the forefront of research into the amiloride-sensitive sodium channel. The cloning of ENaC and subsequently the ASIC channels has revealed a far wider role for this channel family than was previously imagined. In this review, we will discuss the known and potential roles of ENaC and ASIC subunits in the wide variety of pathologies in which these channels have been implicated. Some of these, such as the role of ENaC in Liddle's syndrome are well established, others less so; however, all are related in that the fundamental defect is due to inappropriate channel activity.
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Affiliation(s)
- Yawar J Qadri
- Department of Physiology and Biophysics, University of Alabama at Birmingham, AL 35294, USA
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15
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Abstract
The Hippo kinase pathway is emerging as a conserved signaling pathway that is essential for organ growth and tumorigenesis in Drosophila and mammalians. Although the signaling of the core kinases is relatively well understood, less is known about the upstream inputs, downstream outputs and regulation of the whole cascade. Enrichment of the Hippo pathway components with WW domains and their cognate proline-rich interacting motifs provides a versatile platform for further understanding the mechanisms that regulate organ growth and tumorigenesis. Here, we review recently discovered mechanisms of WW domain-mediated interactions that contribute to the regulation of the Hippo signaling pathway in tumorigenesis. We further discuss new insights and future directions on the emerging role of such regulation.
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Affiliation(s)
- Z Salah
- The Lautenberg Center for General and Tumor Immunology, Department of Immunology and Cancer Research-IMRIC, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
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16
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Jones ES, Owen EP, Davidson JS, Van Der Merwe L, Rayner BL. The R563Q mutation of the epithelial sodium channel beta-subunit is associated with hypertension. Cardiovasc J Afr 2010; 22:241-4. [PMID: 21107496 PMCID: PMC3721827 DOI: 10.5830/cvja-2010-084] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2009] [Accepted: 09/07/2010] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND A high prevalence of the R563Q mutation of the epithelial sodium channel β-subunit has been reported in South African hypertensives compared with unrelated normotensive controls. To delineate the effects of this mutation against a more uniform genetic background, this study investigated the association of the mutation with hypertension within affected kindreds. METHODS Forty-five index patients and members of their kindreds were studied. Blood pressure, serum potassium and the presence of the R563Q mutation were determined. RESULTS Of the 136 individuals studied, 89 were heterozygous for the R563Q mutation and 47 homozygous RR. The mean arterial pressure was significantly higher in the R563Q heterozygous group (p = 0.005) after adjusting for gender, race, age and kindred membership. Of the R563Q heterozygous subjects, 71 (80%) had hypertension, while 17 (36%) of the R563Q homozygous RR subjects were hypertensive. Six R563Q heterozygous subjects had hypokalaemia and one R563Q homozygous RR subject had hypokalaemia, but the difference was not statistically significant. Two heterozygous patients had Liddle's syndrome, both occurring during pregnancy. CONCLUSION The R563Q mutation of β-ENaC is associated with hypertension within affected kindreds, but does not usually cause the full Liddle's syndrome phenotype.
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Affiliation(s)
- E S Jones
- Division of Hypertension, Groote Schuur Hospital and University of Cape Town, South Africa
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17
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Garrone NF, Blazer-Yost BL, Weiss RB, Lalouel JM, Rohrwasser A. A human polymorphism affects NEDD4L subcellular targeting by leading to two isoforms that contain or lack a C2 domain. BMC Cell Biol 2009; 10:26. [PMID: 19364400 PMCID: PMC2678989 DOI: 10.1186/1471-2121-10-26] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2008] [Accepted: 04/13/2009] [Indexed: 11/17/2022] Open
Abstract
Background Ubiquitination serves multiple cellular functions, including proteasomal degradation and the control of stability, function, and intracellular localization of a wide variety of proteins. NEDD4L is a member of the HECT class of E3 ubiquitin ligases. A defining feature of NEDD4L protein isoforms is the presence or absence of an amino-terminal C2 domain, a class of subcellular, calcium-dependent targeting domains. We previously identified a common variant in human NEDD4L that generates isoforms that contain or lack a C2 domain. Results To address the potential functional significance of the NEDD4L common variant on NEDD4L subcellular localization, NEDD4L isoforms that either contained or lacked a C2 domain were tagged with enhanced green fluorescent protein, transfected into Xenopus laevis kidney epithelial cells, and imaged by performing confocal microscopy on live cells. We report that the presence or absence of this C2 domain exerts differential effects on the subcellular distribution of NEDD4L, the ability of C2 containing and lacking NEDD4L isoforms to mobilize in response to a calcium stimulus, and the intracellular transport of subunits of the NEDD4L substrate, ENaC. Furthermore, the ability of the C2-containing isoform to influence β-ENaC mobilization from intracellular pools involves the NEDD4L active site for ubiquitination. We propose a model to account for the potential impact of this common genetic variant on protein function at the cellular level. Conclusion NEDD4L isoforms that contain or lack a C2 domain target different intracellular locations. Additionally, whereas the C2-containing NEDD4L isoform is capable of shuttling between the plasma membrane and intracellular compartments in response to calcium stimulus the C2-lacking isoform can not. The C2-containing isoform differentially affects the mobilization of ENaC subunits from intracellular pools and this trafficking step requires NEDD4L ubiquitin ligase activity. This observation suggests a new mechanism for the requirement for the PY motif in cAMP-mediated exocytosis of ENaC. We have elucidated how a common genetic variant can underlie significant functional diversity in NEDD4L at the cellular level. We propose a model that describes how that functional variation may influence blood pressure. Moreover, our observations regarding differential function of the NEDD4L isoforms may impact other aspects of physiology that involve this ubiquitin ligase.
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Affiliation(s)
- Nicholas F Garrone
- Department of Human Genetics, Eccles Institute of Human Genetics, University of Utah School of Medicine, Salt Lake City, USA.
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Abstract
Hypertension is a serious medical problem affecting a large population worldwide. Liddle syndrome is a hereditary form of early onset hypertension caused by mutations in the epithelial Na+ channel (ENaC). The mutated region, called the PY (Pro-Pro-x-Tyr) motif, serves as a binding site for Nedd4-2, an E3 ubiquitin ligase from the HECT family. Nedd4-2 binds the ENaC PY motif via its WW domains, normally leading to ENaC ubiquitylation and endocytosis, reducing the number of active channels at the plasma membrane. In Liddle syndrome, this endocytosis is impaired due to the inability of the mutated PY motif in ENaC to properly bind Nedd4-2. This leads to accumulation of active channels at the cell surface and increased Na+ (and fluid) absorption in the distal nephron, resulting in elevated blood volume and blood pressure. Small molecules/compounds that destabilize cell surface ENaC, or enhance Nedd4-2 activity in the kidney, could potentially serve to alleviate hypertension. Republished from Current BioData's Targeted Proteins database (TPdb; ).
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Affiliation(s)
- Daniela Rotin
- Program in Cell Biology, The Hospital for Sick Children, and Biochemistry Department, University of Toronto, Ontario, M5G 1X8, Canada.
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Rosskopf D, Schürks M, Rimmbach C, Schäfers R. Genetics of arterial hypertension and hypotension. Naunyn Schmiedebergs Arch Pharmacol 2007; 374:429-69. [PMID: 17262198 DOI: 10.1007/s00210-007-0133-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2006] [Accepted: 12/22/2006] [Indexed: 01/13/2023]
Abstract
Human hypertension affects affects more than 20% of the adult population in industrialized countries, and it is implicated in millions of deaths worldwide each year from stroke, heart failure and ischemic heart disease. Available evidence suggests a major genetic impact on blood pressure regulation. Studies in monogenic hypertension revealed that renal salt and volume regulation systems are predominantly involved in the genesis of these disorders. Mutations here affect the synthesis of mineralocorticoids, the function of the mineralocorticoid receptor, epithelial sodium channels and their regulation by a new class of kinases, termed WNK kinases. It has been learned from monogenic hypotension that almost all ion transporters involved in the renal uptake of Na(+) have a major impact on blood pressure regulation. For essential hypertension as a complex disease, many candidate genes have been analysed. These include components of the renin-angiotensin-aldosterone system, adducin, beta-adrenoceptors, G protein subunits, regulators of G protein signalling (RGS) proteins, Rho kinases and G protein receptor kinases. At present, the individual impact of common polymorphisms in these genes on the observed blood pressure variation, on risk for stroke and as predictors of antihypertensive responses remains small and clinically irrelevant. Nevertheless, these studies have greatly augmented our knowledge on the regulation of renal functions, cellular signal transduction and the integration of both. Together, this provides the basis for the identification of novel drug targets and, hopefully, innovative antihypertensive drugs.
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Affiliation(s)
- Dieter Rosskopf
- Department Pharmacology, Research Center for Pharmacology and Experimental Therapeutics, Ernst-Moritz-Arndt-University Greifswald, Friedrich Loeffler Str. 23d, 17487 Greifswald, Germany.
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Debonneville C, Staub O. Participation of the ubiquitin-conjugating enzyme UBE2E3 in Nedd4-2-dependent regulation of the epithelial Na+ channel. Mol Cell Biol 2004; 24:2397-409. [PMID: 14993279 PMCID: PMC355826 DOI: 10.1128/mcb.24.6.2397-2409.2004] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The epithelial Na+ channel (ENaC) is a heteromeric protein complex playing a fundamental role in Na+ homeostasis and blood pressure regulation. Specific mutations inactivating PY motifs in ENaC C termini cause Liddle's syndrome, an inherited form of hypertension. Previously we showed that these PY motifs serve as binding sites for the E3 enzyme Nedd4-2, implying ubiquitination as a regulatory mechanism of ENaC. Ubiquitination involves the sequential action of E1, E2, and E3 enzymes. Here we identify the E2 enzyme UBE2E3, which acts in concert with Nedd4-2, and show by coimmunoprecipitation that UBE2E3 and Nedd4-2 interact together. In Xenopus laevis oocytes, UBE2E3 reduces ENaC activity marginally, consistent with Nedd4-2 being the rate-limiting factor in this process, whereas a catalytically inactive mutant of UBE2E3 (UBE2E3-CS) causes elevated ENaC activity by increasing cell surface expression. No additive effect is observed when UBE2E3-CS is coexpressed with an inactive Nedd4-2 mutant, and the stimulatory role of UBE2E3-CS depends on the integrity of the PY motifs (Nedd4-2 binding sites) and the ubiquitination sites on ENaC. In renal mpkCCD(cl4) cells, displaying ENaC-dependent transepithelial Na+ transport, Nedd4-2 and UBE2E3 can be coimmunoprecipitated and overexpression of UBE2E3 affects Na+ transport, corroborating the concept of a concerted action of UBE2E3 and Nedd4-2 in ENaC regulation.
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Affiliation(s)
- Christophe Debonneville
- Department of Pharmacology and Toxicology, University of Lausanne, CH-1005 Lausanne, Switzerland
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Bruns JB, Hu B, Ahn YJ, Sheng S, Hughey RP, Kleyman TR. Multiple epithelial Na+ channel domains participate in subunit assembly. Am J Physiol Renal Physiol 2003; 285:F600-9. [PMID: 12770839 DOI: 10.1152/ajprenal.00095.2003] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Epithelial sodium channels (ENaCs) are composed of three structurally related subunits that form a tetrameric channel. The Xenopus laevis oocyte expression system was used to identify regions within the ENaC alpha-subunit that confer a dominant negative phenotype on functional expression of alphabetagamma-ENaC to define domains that have a role in subunit-subunit interactions. Coexpression of full-length mouse alphabetagamma-ENaC with either 1) the alpha-subunit first membrane-spanning domain and short downstream hydrophobic domain (alpha-M1H1); 2) alpha-M1H1 and its downstream hydrophilic extracellular loop (alpha-M1H1-ECL); 3) the membrane-spanning domain of a control type 2 transmembrane protein (glutamyl transpeptidase; gamma-GT) fused to the alpha-ECL (gamma-GT-alpha-ECL); 4) the extracellular domain of a control type 1 transmembrane protein (Tac) fused to the alpha-subunit second membrane-spanning domain and short upstream hydrophobic domain (Tac-alpha-H2M2); or 5) the alpha-subunit cytoplasmic COOH terminus (alpha-Ct) significantly reduced amiloride-sensitive Na+ currents in X. laevis oocytes. Functional expression of Na+ channels was not inhibited when full-length alphabetagamma-ENaC was coexpressed with either 1) the alpha-ECL lacking a signal-anchor sequence, 2) alpha-M1H1 and alpha-Ct expressed as a fusion protein, 3) full-length gamma-GT, or 4) full-length Tac. Furthermore, the expression of ROMK channels was not inhibited when full-length ROMK was coexpressed with either alpha-M1H1-ECL or alpha-Ct. Full-length FLAG-tagged alpha-, beta-, or gamma-ENaC coimmunoprecipitated with myc-tagged alpha-M1H1-ECL, whereas wild-type gamma-GT did not. These data suggest that multiple sites within the alpha-subunit participate in subunit-subunit interactions that are required for proper assembly of the heterooligomeric ENaC complex.
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Affiliation(s)
- James B Bruns
- Department of Medicine, University of Pittsburgh, 15261, USA
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22
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Debonneville C, Flores SY, Kamynina E, Plant PJ, Tauxe C, Thomas MA, Münster C, Chraïbi A, Pratt J, Horisberger JD, Pearce D, Loffing J, Staub O. Phosphorylation of Nedd4-2 by Sgk1 regulates epithelial Na(+) channel cell surface expression. EMBO J 2001; 20:7052-9. [PMID: 11742982 PMCID: PMC125341 DOI: 10.1093/emboj/20.24.7052] [Citation(s) in RCA: 542] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The epithelial Na(+) channel (ENaC) plays an essential role in the regulation of whole body Na(+) balance and blood pressure. The cell surface expression of this channel, a complex of three subunits (alpha, beta and gamma ENaC), has been shown to be regulated by hormones such as aldosterone and vasopressin and by intracellular signaling, including ubiquitylation and/or phosphorylation. However, the molecular mechanisms involving phosphorylation in the regulation of ENaC are unclear. Here we show by expression studies in Xenopus laevis oocytes that the aldosterone-induced Sgk1 kinase interacts with the ubiquitin protein ligase Nedd4-2 in a PY motif-dependent manner and phosphorylates Nedd4-2 on Ser444 and, to a lesser extent, Ser338. Such phosphorylation reduces the interaction between Nedd4-2 and ENaC, leading to elevated ENaC cell surface expression. These data show that phosphorylation of an enzyme involved in the ubiquitylation cascade (Nedd4-2) controls cell surface density of ENaC and propose a paradigm for the control of ion channels. Moreover, they suggest a novel and complete signaling cascade for aldosterone-dependent regulation of ENaC.
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Affiliation(s)
| | | | | | | | | | | | | | | | - J.Howard Pratt
- Institute of Pharmacology and Toxicology, University of Lausanne, CH-1005 Lausanne,
Institute of Anatomy, University of Zurich, CH-8057 Zurich, Switzerland, Endocrinology/Hypertension, Department of Medicine, Indiana University, Indianapolis, IN 46202 and Department of Medicine and Department of Cellular and Molecular Pharmacology, University of San Francisco, San Francisco, CA 94143, USA Corresponding author e-mail: C.Debonneville and S.Y.Flores contributed equally to this work
| | | | - David Pearce
- Institute of Pharmacology and Toxicology, University of Lausanne, CH-1005 Lausanne,
Institute of Anatomy, University of Zurich, CH-8057 Zurich, Switzerland, Endocrinology/Hypertension, Department of Medicine, Indiana University, Indianapolis, IN 46202 and Department of Medicine and Department of Cellular and Molecular Pharmacology, University of San Francisco, San Francisco, CA 94143, USA Corresponding author e-mail: C.Debonneville and S.Y.Flores contributed equally to this work
| | - Johannes Loffing
- Institute of Pharmacology and Toxicology, University of Lausanne, CH-1005 Lausanne,
Institute of Anatomy, University of Zurich, CH-8057 Zurich, Switzerland, Endocrinology/Hypertension, Department of Medicine, Indiana University, Indianapolis, IN 46202 and Department of Medicine and Department of Cellular and Molecular Pharmacology, University of San Francisco, San Francisco, CA 94143, USA Corresponding author e-mail: C.Debonneville and S.Y.Flores contributed equally to this work
| | - Olivier Staub
- Institute of Pharmacology and Toxicology, University of Lausanne, CH-1005 Lausanne,
Institute of Anatomy, University of Zurich, CH-8057 Zurich, Switzerland, Endocrinology/Hypertension, Department of Medicine, Indiana University, Indianapolis, IN 46202 and Department of Medicine and Department of Cellular and Molecular Pharmacology, University of San Francisco, San Francisco, CA 94143, USA Corresponding author e-mail: C.Debonneville and S.Y.Flores contributed equally to this work
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23
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Abriel H, Loffing J, Rebhun JF, Pratt JH, Schild L, Horisberger JD, Rotin D, Staub O. Defective regulation of the epithelial Na+ channel by Nedd4 in Liddle's syndrome. J Clin Invest 1999; 103:667-73. [PMID: 10074483 PMCID: PMC408130 DOI: 10.1172/jci5713] [Citation(s) in RCA: 289] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Liddle's syndrome is an inherited form of hypertension linked to mutations in the epithelial Na+ channel (ENaC). ENaC is composed of three subunits (alpha, beta, gamma), each containing a COOH-terminal PY motif (xPPxY). Mutations causing Liddle's syndrome alter or delete the PY motifs of beta- or gamma-ENaC. We recently demonstrated that the ubiquitin-protein ligase Nedd4 binds these PY motifs and that ENaC is regulated by ubiquitination. Here, we investigate, using the Xenopus oocyte system, whether Nedd4 affects ENaC function. Overexpression of wild-type Nedd4, together with ENaC, inhibited channel activity, whereas a catalytically inactive Nedd4 stimulated it, likely by acting as a competitive antagonist to endogenous Nedd4. These effects were dependant on the PY motifs, because no Nedd4-mediated changes in channel activity were observed in ENaC lacking them. The effect of Nedd4 on ENaC missing only one PY motif (of beta-ENaC), as originally described in patients with Liddle's syndrome, was intermediate. Changes were due entirely to alterations in ENaC numbers at the plasma membrane, as determined by surface binding and immunofluorescence. Our results demonstrate that Nedd4 is a negative regulator of ENaC and suggest that the loss of Nedd4 binding sites in ENaC observed in Liddle's syndrome may explain the increase in channel number at the cell surface, increased Na+ reabsorption by the distal nephron, and hence the hypertension.
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Affiliation(s)
- H Abriel
- Institute of Pharmacology and Toxicology, University of Lausanne, CH-1005 Lausanne, Switzerland
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