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Bai H, Zhou R, Barravecchia M, Norman R, Friedman A, Yu D, Lin X, Young JL, Dean DA. The Na+, K+-ATPase β1 subunit regulates epithelial tight junctions via MRCKα. JCI Insight 2021; 6:134881. [PMID: 33507884 PMCID: PMC7934944 DOI: 10.1172/jci.insight.134881] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Accepted: 01/13/2021] [Indexed: 12/12/2022] Open
Abstract
An intact lung epithelial barrier is essential for lung homeostasis. The Na+, K+-ATPase (NKA), primarily serving as an ion transporter, also regulates epithelial barrier function via modulation of tight junctions. However, the underlying mechanism is not well understood. Here, we show that overexpression of the NKA β1 subunit upregulates the expression of tight junction proteins, leading to increased alveolar epithelial barrier function by an ion transport–independent mechanism. Using IP and mass spectrometry, we identified a number of unknown protein interactions of the β1 subunit, including a top candidate, myotonic dystrophy kinase–related cdc42-binding kinase α (MRCKα), which is a protein kinase known to regulate peripheral actin formation. Using a doxycycline-inducible gene expression system, we demonstrated that MRCKα and its downstream activation of myosin light chain is required for the regulation of alveolar barrier function by the NKA β1 subunit. Importantly, MRCKα is expressed in both human airways and alveoli and has reduced expression in patients with acute respiratory distress syndrome (ARDS), a lung illness that can be caused by multiple direct and indirect insults, including the infection of influenza virus and SARS-CoV-2. Our results have elucidated a potentially novel mechanism by which NKA regulates epithelial tight junctions and have identified potential drug targets for treating ARDS and other pulmonary diseases that are caused by barrier dysfunction.
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Affiliation(s)
- Haiqing Bai
- Department of Pediatrics and.,Department of Pathology, School of Medicine and Dentistry, University of Rochester, Rochester, New York, USA
| | | | | | | | - Alan Friedman
- Department of Pediatrics and.,Department of Materials Design and Innovation, School of Engineering and Applied Sciences, University at Buffalo, Buffalo, New York, USA
| | | | - Xin Lin
- Department of Pediatrics and
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Shrivastava AN, Triller A, Melki R. Cell biology and dynamics of Neuronal Na +/K +-ATPase in health and diseases. Neuropharmacology 2018; 169:107461. [PMID: 30550795 DOI: 10.1016/j.neuropharm.2018.12.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 11/17/2018] [Accepted: 12/08/2018] [Indexed: 10/27/2022]
Abstract
Neuronal Na+/K+-ATPase is responsible for the maintenance of ionic gradient across plasma membrane. In doing so, in a healthy brain, Na+/K+-ATPase activity accounts for nearly half of total brain energy consumption. The α3-subunit containing Na+/K+-ATPase expression is restricted to neurons. Heterozygous mutations within α3-subunit leads to Rapid-onset Dystonia Parkinsonism, Alternating Hemiplegia of Childhood and other neurological and neuropsychiatric disorders. Additionally, proteins such as α-synuclein, amyloid-β, tau and SOD1 whose aggregation is associated to neurodegenerative diseases directly bind and impair α3-Na+/K+-ATPase activity. The review will provide a summary of neuronal α3-Na+/K+-ATPase functional properties, expression pattern, protein-protein interactions at the plasma membrane, biophysical properties (distribution and lateral diffusion). Lastly, the role of α3-Na+/K+-ATPase in neurological and neurodegenerative disorders will be discussed. This article is part of the special issue entitled 'Mobility and trafficking of neuronal membrane proteins'.
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Affiliation(s)
- Amulya Nidhi Shrivastava
- CEA, Institut François Jacob (MIRcen) and CNRS, Laboratory of Neurodegenerative Diseases (U9199), 18 Route du Panorama, 92265, Fontenay-aux-Roses, France.
| | - Antoine Triller
- Institut de Biologie de l'ENS (IBENS), École Normale Supérieure, INSERM, CNRS, PSL, Research University, 46 Rue d'Ulm, 75005 Paris, France
| | - Ronald Melki
- CEA, Institut François Jacob (MIRcen) and CNRS, Laboratory of Neurodegenerative Diseases (U9199), 18 Route du Panorama, 92265, Fontenay-aux-Roses, France
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Regulation of Neuronal Na,K-ATPase by Extracellular Scaffolding Proteins. Int J Mol Sci 2018; 19:ijms19082214. [PMID: 30060621 PMCID: PMC6121408 DOI: 10.3390/ijms19082214] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 07/24/2018] [Accepted: 07/25/2018] [Indexed: 12/19/2022] Open
Abstract
Neuronal activity leads to an influx of Na⁺ that needs to be rapidly cleared. The sodium-potassium ATPase (Na,K-ATPase) exports three Na⁺ ions and imports two K⁺ ions at the expense of one ATP molecule. Na,K-ATPase turnover accounts for the majority of energy used by the brain. To prevent an energy crisis, the energy expense for Na⁺ clearance must provide an optimal effect. Here we report that in rat primary hippocampal neurons, the clearance of Na⁺ ions is more efficient if Na,K-ATPase is laterally mobile in the membrane than if it is clustered. Using fluorescence recovery after photobleaching and single particle tracking analysis, we show that the ubiquitous α1 and the neuron-specific α3 catalytic subunits as well as the supportive β1 subunit of Na,K-ATPase are highly mobile in the plasma membrane. We show that cross-linking of the β1 subunit with polyclonal antibodies or exposure to Modulator of Na,K-ATPase (MONaKA), a secreted protein which binds to the extracellular domain of the β subunit, clusters the α3 subunit in the membrane and restricts its mobility. We demonstrate that clustering, caused by cross-linking or by exposure to MONaKA, reduces the efficiency in restoring intracellular Na⁺. These results demonstrate that extracellular interactions with Na,K-ATPase regulate the Na⁺ extrusion efficiency with consequences for neuronal energy balance.
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Multiple genes, especially immune-regulating genes, contribute to disease susceptibility in systemic sclerosis. Curr Opin Rheumatol 2016; 28:595-605. [DOI: 10.1097/bor.0000000000000334] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Regulation of cough by neuronal Na(+)-K(+) ATPases. Curr Opin Pharmacol 2015; 22:140-5. [PMID: 26048736 DOI: 10.1016/j.coph.2015.05.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Revised: 04/29/2015] [Accepted: 05/01/2015] [Indexed: 01/10/2023]
Abstract
The Na(+)-K(+) ATPases play an essential role in establishing the sodium gradients in excitable cells. Multiple isoforms of the sodium pumps have been identified, with tissue and cell specific expression patterns. Because the vagal afferent nerves regulating cough must be activated at sustained high frequencies of action potential patterning to achieve cough initiation thresholds, it is a certainty that sodium pump function is essential to maintaining cough reflex sensitivities in health and in disease. The mechanisms by which Na(+)-K(+) ATPases regulate bronchopulmonary vagal afferent nerve excitability are reviewed as are potential therapeutic strategies targeting the sodium pumps in cough.
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Vaughn SE, Foley C, Lu X, Patel ZH, Zoller EE, Magnusen AF, Williams AH, Ziegler JT, Comeau ME, Marion MC, Glenn SB, Adler A, Shen N, Nath S, Stevens AM, Freedman BI, Tsao BP, Jacob CO, Kamen DL, Brown EE, Gilkeson GS, Alarcón GS, Reveille JD, Anaya JM, James JA, Moser KL, Criswell LA, Vilá LM, Alarcón-Riquelme ME, Petri M, Scofield RH, Kimberly RP, Ramsey-Goldman R, Binjoo Y, Choi J, Bae SC, Boackle SA, Vyse TJ, Guthridge JM, Namjou B, Gaffney PM, Langefeld CD, Kaufman KM, Kelly JA, Harley ITW, Harley JB, Kottyan LC. Lupus risk variants in the PXK locus alter B-cell receptor internalization. Front Genet 2015; 5:450. [PMID: 25620976 PMCID: PMC4288052 DOI: 10.3389/fgene.2014.00450] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Accepted: 12/09/2014] [Indexed: 01/17/2023] Open
Abstract
Genome wide association studies have identified variants in PXK that confer risk for humoral autoimmune diseases, including systemic lupus erythematosus (SLE or lupus), rheumatoid arthritis and more recently systemic sclerosis. While PXK is involved in trafficking of epidermal growth factor Receptor (EGFR) in COS-7 cells, mechanisms linking PXK to lupus pathophysiology have remained undefined. In an effort to uncover the mechanism at this locus that increases lupus-risk, we undertook a fine-mapping analysis in a large multi-ancestral study of lupus patients and controls. We define a large (257kb) common haplotype marking a single causal variant that confers lupus risk detected only in European ancestral populations and spans the promoter through the 3′ UTR of PXK. The strongest association was found at rs6445972 with P < 4.62 × 10−10, OR 0.81 (0.75–0.86). Using stepwise logistic regression analysis, we demonstrate that one signal drives the genetic association in the region. Bayesian analysis confirms our results, identifying a 95% credible set consisting of 172 variants spanning 202 kb. Functionally, we found that PXK operates on the B-cell antigen receptor (BCR); we confirmed that PXK influenced the rate of BCR internalization. Furthermore, we demonstrate that individuals carrying the risk haplotype exhibited a decreased rate of BCR internalization, a process known to impact B cell survival and cell fate. Taken together, these data define a new candidate mechanism for the genetic association of variants around PXK with lupus risk and highlight the regulation of intracellular trafficking as a genetically regulated pathway mediating human autoimmunity.
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Affiliation(s)
- Samuel E Vaughn
- Immunology Graduate Program and Medical Scientist Training Program, University of Cincinnati College of Medicine Cincinnati, OH, USA ; Center for Autoimmune Genomics and Etiology, Cincinnati Children's Hospital Medical Center Cincinnati, OH, USA
| | | | - Xiaoming Lu
- Center for Autoimmune Genomics and Etiology, Cincinnati Children's Hospital Medical Center Cincinnati, OH, USA
| | - Zubin H Patel
- Immunology Graduate Program and Medical Scientist Training Program, University of Cincinnati College of Medicine Cincinnati, OH, USA ; Center for Autoimmune Genomics and Etiology, Cincinnati Children's Hospital Medical Center Cincinnati, OH, USA
| | - Erin E Zoller
- Center for Autoimmune Genomics and Etiology, Cincinnati Children's Hospital Medical Center Cincinnati, OH, USA
| | - Albert F Magnusen
- Center for Autoimmune Genomics and Etiology, Cincinnati Children's Hospital Medical Center Cincinnati, OH, USA
| | - Adrienne H Williams
- Center for Public Health Genomics and the Department of Biostatistical Sciences, Wake Forest School of Medicine Winston-Salem, NC, USA
| | - Julie T Ziegler
- Center for Public Health Genomics and the Department of Biostatistical Sciences, Wake Forest School of Medicine Winston-Salem, NC, USA
| | - Mary E Comeau
- Center for Public Health Genomics and the Department of Biostatistical Sciences, Wake Forest School of Medicine Winston-Salem, NC, USA
| | - Miranda C Marion
- Center for Public Health Genomics and the Department of Biostatistical Sciences, Wake Forest School of Medicine Winston-Salem, NC, USA
| | - Stuart B Glenn
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation Oklahoma City, OK, USA
| | - Adam Adler
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation Oklahoma City, OK, USA
| | - Nan Shen
- Immunology Graduate Program and Medical Scientist Training Program, University of Cincinnati College of Medicine Cincinnati, OH, USA ; Joint Molecular Rheumatology Laboratory of the Institute of Health Sciences and Shanghai Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Institutes for Biological Sciences, and Chinese Academy of Sciences Shanghai, China
| | - Swapan Nath
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation Oklahoma City, OK, USA
| | - Anne M Stevens
- Center for Immunity and Immunotherapies, Seattle Children's Research Institute Seattle, WA, USA ; Division of Rheumatology, Department of Pediatrics, University of Washington Seattle, WA, USA
| | - Barry I Freedman
- Department of Internal Medicine, Section on Nephrology, Wake Forest School of Medicine Winston-Salem, NC, USA
| | - Betty P Tsao
- Division of Rheumatology, Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles Los Angeles, CA, USA
| | - Chaim O Jacob
- Department of Medicine, Keck School of Medicine, University of Southern California Los Angeles, CA, USA
| | - Diane L Kamen
- Division of Rheumatology, Medical University of South Carolina Charleston, SC, USA
| | - Elizabeth E Brown
- Department of Epidemiology, University of Alabama at Birmingham Birmingham, AL, USA ; Department of Medicine, University of Alabama at Birmingham Birmingham, AL, USA
| | - Gary S Gilkeson
- Division of Rheumatology, Medical University of South Carolina Charleston, SC, USA
| | - Graciela S Alarcón
- Department of Medicine, University of Alabama at Birmingham Birmingham, AL, USA
| | - John D Reveille
- Rheumatology and Clinical Immunogenetics, University of Texas Health Science Center at Houston Houston, TX, USA
| | - Juan-Manuel Anaya
- Center for Autoimmune Disease Research, Universidad del Rosario Bogota, Colombia
| | - Judith A James
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation Oklahoma City, OK, USA ; Department of Medicine, University of Oklahoma Health Sciences Center Oklahoma City, OK, USA
| | - Kathy L Moser
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation Oklahoma City, OK, USA
| | - Lindsey A Criswell
- Rosalind Russell/Ephraim P Engleman Rheumatology Research Research Center, Department of Medicine, University of California, San Francisco San Francisco, CA, USA
| | - Luis M Vilá
- Division of Rheumatology, Department of Medicine, University of Puerto Rico Medical Sciences Campus San Juan, PR, USA
| | - Marta E Alarcón-Riquelme
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation Oklahoma City, OK, USA ; Center for Genomics and Oncological Research, Pfizer-University of Granada-Junta de Andalucia Granada, Spain
| | - Michelle Petri
- Department of Medicine, Johns Hopkins University School of Medicine Baltimore, MD, USA
| | - R Hal Scofield
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation Oklahoma City, OK, USA ; Department of Medicine, University of Oklahoma Health Sciences Center Oklahoma City, OK, USA ; United States Department of Veterans Affairs Medical Center Oklahoma City, OK, USA
| | - Robert P Kimberly
- Department of Medicine, University of Alabama at Birmingham Birmingham, AL, USA
| | - Rosalind Ramsey-Goldman
- Division of Rheumatology, Feinberg School of Medicine, Northwestern University Chicago, IL, USA
| | - Young Binjoo
- Department of Rheumatology, Hanyang University Hospital for Rheumatic Diseases Seoul, Korea
| | - Jeongim Choi
- Department of Rheumatology, Hanyang University Hospital for Rheumatic Diseases Seoul, Korea
| | - Sang-Cheol Bae
- Department of Rheumatology, Hanyang University Hospital for Rheumatic Diseases Seoul, Korea
| | - Susan A Boackle
- Division of Rheumatology, University of Colorado School of Medicine Aurora, CO, USA
| | - Timothy J Vyse
- Divisions of Genetics and Molecular Medicine and Immunology, King's College London London, UK
| | - Joel M Guthridge
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation Oklahoma City, OK, USA
| | - Bahram Namjou
- Center for Autoimmune Genomics and Etiology, Cincinnati Children's Hospital Medical Center Cincinnati, OH, USA
| | - Patrick M Gaffney
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation Oklahoma City, OK, USA
| | - Carl D Langefeld
- Center for Public Health Genomics and the Department of Biostatistical Sciences, Wake Forest School of Medicine Winston-Salem, NC, USA
| | - Kenneth M Kaufman
- Center for Autoimmune Genomics and Etiology, Cincinnati Children's Hospital Medical Center Cincinnati, OH, USA ; United States Department of Veterans Affairs Medical Center Cincinnati, OH, USA
| | - Jennifer A Kelly
- Arthritis and Clinical Immunology Research Program, Oklahoma Medical Research Foundation Oklahoma City, OK, USA
| | - Isaac T W Harley
- Immunology Graduate Program and Medical Scientist Training Program, University of Cincinnati College of Medicine Cincinnati, OH, USA ; Center for Autoimmune Genomics and Etiology, Cincinnati Children's Hospital Medical Center Cincinnati, OH, USA
| | - John B Harley
- Center for Autoimmune Genomics and Etiology, Cincinnati Children's Hospital Medical Center Cincinnati, OH, USA ; United States Department of Veterans Affairs Medical Center Cincinnati, OH, USA
| | - Leah C Kottyan
- Center for Autoimmune Genomics and Etiology, Cincinnati Children's Hospital Medical Center Cincinnati, OH, USA ; United States Department of Veterans Affairs Medical Center Cincinnati, OH, USA
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Niu L, Huang W, Umbach DM, Li L. IUTA: a tool for effectively detecting differential isoform usage from RNA-Seq data. BMC Genomics 2014; 15:862. [PMID: 25283306 PMCID: PMC4195885 DOI: 10.1186/1471-2164-15-862] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Accepted: 09/29/2014] [Indexed: 01/10/2023] Open
Abstract
Background Most genes in mammals generate several transcript isoforms that differ in stability and translational efficiency through alternative splicing. Such alternative splicing can be tissue- and developmental stage-specific, and such specificity is sometimes associated with disease. Thus, detecting differential isoform usage for a gene between tissues or cell lines/types (differences in the fraction of total expression of a gene represented by the expression of each of its isoforms) is potentially important for cell and developmental biology. Results We present a new method IUTA that is designed to test each gene in the genome for differential isoform usage between two groups of samples. IUTA also estimates isoform usage for each gene in each sample as well as averaged across samples within each group. IUTA is the first method to formulate the testing problem as testing for equal means of two probability distributions under the Aitchison geometry, which is widely recognized as the most appropriate geometry for compositional data (vectors that contain the relative amount of each component comprising the whole). Evaluation using simulated data showed that IUTA was able to provide test results for many more genes than was Cuffdiff2 (version 2.2.0, released in Mar. 2014), and IUTA performed better than Cuffdiff2 for the limited number of genes that Cuffdiff2 did analyze. When applied to actual mouse RNA-Seq datasets from six tissues, IUTA identified 2,073 significant genes with clear patterns of differential isoform usage between a pair of tissues. IUTA is implemented as an R package and is available at http://www.niehs.nih.gov/research/resources/software/biostatistics/iuta/index.cfm. Conclusions Both simulation and real-data results suggest that IUTA accurately detects differential isoform usage. We believe that our analysis of RNA-seq data from six mouse tissues represents the first comprehensive characterization of isoform usage in these tissues. IUTA will be a valuable resource for those who study the roles of alternative transcripts in cell development and disease. Electronic supplementary material The online version of this article (doi:10.1186/1471-2164-15-862) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | | | | | - Leping Li
- Biostatistics Branch, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA.
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Jin J, Chou C, Lima M, Zhou D, Zhou X. Systemic Sclerosis is a Complex Disease Associated Mainly with Immune Regulatory and Inflammatory Genes. Open Rheumatol J 2014; 8:29-42. [PMID: 25328554 PMCID: PMC4200700 DOI: 10.2174/1874312901408010029] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Revised: 08/04/2014] [Accepted: 08/07/2014] [Indexed: 12/21/2022] Open
Abstract
Systemic sclerosis (SSc) is a fibrotic and autoimmune disease characterized clinically by skin and internal organ fibrosis and vascular damage, and serologically by the presence of circulating autoantibodies. Although etiopathogenesis is not yet well understood, the results of numerous genetic association studies support genetic contributions as an important factor to SSc. In this paper, the major genes of SSc are reviewed. The most recent genome-wide association studies (GWAS) are taken into account along with robust candidate gene studies. The literature search was performed on genetic association studies of SSc in PubMed between January 2000 and March 2014 while eligible studies generally had over 600 total participants with replication. A few genetic association studies with related functional changes in SSc patients were also included. A total of forty seven genes or specific genetic regions were reported to be associated with SSc, although some are controversial. These genes include HLA genes, STAT4, CD247, TBX21, PTPN22, TNFSF4, IL23R, IL2RA, IL-21, SCHIP1/IL12A, CD226, BANK1, C8orf13-BLK, PLD4, TLR-2, NLRP1, ATG5, IRF5, IRF8, TNFAIP3, IRAK1, NFKB1, TNIP1, FAS, MIF, HGF, OPN, IL-6, CXCL8, CCR6, CTGF, ITGAM, CAV1, MECP2, SOX5, JAZF1, DNASEIL3, XRCC1, XRCC4, PXK, CSK, GRB10, NOTCH4, RHOB, KIAA0319, PSD3 and PSOR1C1. These genes encode proteins mainly involved in immune regulation and inflammation, and some of them function in transcription, kinase activity, DNA cleavage and repair. The discovery of various SSc-associated genes is important in understanding the genetics of SSc and potential pathogenesis that contribute to the development of this disease.
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Affiliation(s)
- Jingxiao Jin
- University of Texas Medical School at Houston, USA ; Duke University, USA
| | - Chou Chou
- University of Texas Medical School at Houston, USA
| | - Maria Lima
- University of Texas Medical School at Houston, USA ; Rice University, USA
| | - Danielle Zhou
- University of Texas Medical School at Houston, USA ; Washington University, USA
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Mroz MS, Keating N, Ward JB, Sarker R, Amu S, Aviello G, Donowitz M, Fallon PG, Keely SJ. Farnesoid X receptor agonists attenuate colonic epithelial secretory function and prevent experimental diarrhoea in vivo. Gut 2014; 63:808-17. [PMID: 23916961 DOI: 10.1136/gutjnl-2013-305088] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/08/2022]
Abstract
OBJECTIVE Bile acids are important regulators of intestinal physiology, and the nuclear bile acid receptor, farnesoid X receptor (FXR), is emerging as a promising therapeutic target for several intestinal disorders. Here, we investigated a role for FXR in regulating intestinal fluid and electrolyte transport and the potential for FXR agonists in treating diarrhoeal diseases. DESIGN Electrogenic ion transport was measured as changes in short-circuit current across voltage-clamped T84 cell monolayers or mouse tissues in Ussing chambers. NHE3 activity was measured as BCECF fluorescence in Caco-2 cells. Protein expression was measured by immunoblotting and cell surface biotinylation. Antidiarrhoeal efficacy of GW4064 was assessed using two in vivo mouse models: the ovalbumin-induced diarrhoea model and cholera toxin (CTX)-induced intestinal fluid accumulation. RESULTS GW4064 (5 μmol/L; 24 h), a specific FXR agonist, induced nuclear translocation of the receptor in T84 cells and attenuated Cl(-) secretory responses to both Ca(2+) and cAMP-dependent agonists. GW4064 also prevented agonist-induced inhibition of NHE3 in Caco-2 cells. In mice, intraperitoneal administration of GW4064 (50 mg/mL) also inhibited Ca(2+) and cAMP-dependent secretory responses across ex vivo colonic tissues and prevented ovalbumin-induced diarrhoea and CTX-induced intestinal fluid accumulation in vivo. At the molecular level, FXR activation attenuated apical Cl(-) currents by inhibiting expression of cystic fibrosis transmembrane conductance regulator channels and inhibited basolateral Na(+)/K(+)-ATPase activity without altering expression of the protein. CONCLUSIONS These data reveal a novel antisecretory role for the FXR in colonic epithelial cells and suggest that FXR agonists have excellent potential for development as a new class of antidiarrheal drugs.
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Affiliation(s)
- Magdalena S Mroz
- Department of Molecular Medicine, RCSI Education and Research Centre, Beaumont Hospital, , Dublin, Ireland
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Oparina NY, Delgado-Vega AM, Martinez-Bueno M, Magro-Checa C, Fernández C, Castro RO, Pons-Estel BA, D'Alfonso S, Sebastiani GD, Witte T, Lauwerys BR, Endreffy E, Kovács L, Escudero A, López-Pedrera C, Vasconcelos C, da Silva BM, Frostegård J, Truedsson L, Martin J, Raya E, Ortego-Centeno N, de los Angeles Aguirre M, de Ramón Garrido E, Palma MJC, Alarcon-Riquelme ME, Kozyrev SV. PXKlocus in systemic lupus erythematosus: fine mapping and functional analysis reveals novel susceptibility geneABHD6. Ann Rheum Dis 2014; 74:e14. [DOI: 10.1136/annrheumdis-2013-204909] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Zhou XJ, Cheng FJ, Zhu L, Lv JC, Qi YY, Hou P, Zhang H. Association of systemic lupus erythematosus susceptibility genes with IgA nephropathy in a Chinese cohort. Clin J Am Soc Nephrol 2014; 9:788-97. [PMID: 24458077 DOI: 10.2215/cjn.01860213] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
BACKGROUND AND OBJECTIVES One hypothesis states that IgA nephropathy (IgAN) is a syndrome with an autoimmune component. Recent studies strongly support the notion of shared genetics between immune-related diseases. This study investigated single-nucleotide polymorphisms (SNPs) reported to be associated with systemic lupus erythematosus (SLE) in a Chinese cohort of patients with IgAN and in controls. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS This study investigated whether SNP markers that had been reported to be associated with SLE were also associated with IgAN in a Chinese population. The study cohort consisted of 1194 patients with IgAN and 902 controls enrolled in Peking University First Hospital from 1997 to 2008. RESULTS Ninety-six SNPs mapping to 60 SLE loci with reported P values <1 × 10(-5) were investigated. CFH (P=8.41 × 10(-6)), HLA-DRA (P=4.91 × 10(-6)), HLA-DRB1 (P=9.46 × 10(-9)), PXK (P=3.62 × 10(-4)), BLK (P=9.32 × 10(-3)), and UBE2L3 (P=4.07 × 10(-3)) were identified as shared genes between IgAN and SLE. All associations reported herein were corroborated by associations at neighboring SNPs. Many of the alleles that are risk alleles for SLE are protective alleles for IgAN. By analyses of two open independent expression quantitative trait loci (eQTL) databases, correlations between genotypes and corresponding gene expression were observed (P<0.05 in multiple populations), suggesting a cis-eQTL effect. From gene-expression databases, differential expressions of these genes were observed in IgAN. Additive interactions between PXK rs6445961 and HLA-DRA rs9501626 (P=1.51 × 10(-2)), as well as multiplicative interactions between CFH rs6677604 and HLA-DRB1 rs9271366 (P=1.77 × 10(-2)), and between HLA-DRA rs9501626 and HLA-DRB1 rs9271366 (P=3.23 × 10(-2)) were observed. Disease risk decreased with accumulation of protective alleles. Network analyses highlighted four pathways: MHC class II antigen presentation, complement regulation, signaling by the B-cell receptor, and ubiquitin/proteasome-dependent degradation. CONCLUSION From this "systems genetics" perspective, these data provide important clues for future studies on pleiotropy in IgAN and lupus nephritis.
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Affiliation(s)
- Xu-Jie Zhou
- Renal Division, Peking University First Hospital; Peking University Institute of Nephrology; Key Laboratory of Renal Disease, Ministry of Health of China
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Kelly OB, Mroz MS, Ward JBJ, Colliva C, Scharl M, Pellicciari R, Gilmer JF, Fallon PG, Hofmann AF, Roda A, Murray FE, Keely SJ. Ursodeoxycholic acid attenuates colonic epithelial secretory function. J Physiol 2013; 591:2307-18. [PMID: 23507881 DOI: 10.1113/jphysiol.2013.252544] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Dihydroxy bile acids, such as chenodeoxycholic acid (CDCA), are well known to promote colonic fluid and electrolyte secretion, thereby causing diarrhoea associated with bile acid malabsorption. However, CDCA is rapidly metabolised by colonic bacteria to ursodeoxycholic acid (UDCA), the effects of which on epithelial transport are poorly characterised. Here, we investigated the role of UDCA in the regulation of colonic epithelial secretion. Cl(-) secretion was measured across voltage-clamped monolayers of T84 cells and muscle-stripped sections of mouse or human colon. Cell surface biotinylation was used to assess abundance/surface expression of transport proteins. Acute (15 min) treatment of T84 cells with bilateral UDCA attenuated Cl(-) secretory responses to the Ca(2+) and cAMP-dependent secretagogues carbachol (CCh) and forskolin (FSK) to 14.0 ± 3.8 and 40.2 ± 7.4% of controls, respectively (n = 18, P < 0.001). Investigation of the molecular targets involved revealed that UDCA acts by inhibiting Na(+)/K(+)-ATPase activity and basolateral K(+) channel currents, without altering their cell surface expression. In contrast, intraperitoneal administration of UDCA (25 mg kg(-1)) to mice enhanced agonist-induced colonic secretory responses, an effect we hypothesised to be due to bacterial metabolism of UDCA to lithocholic acid (LCA). Accordingly, LCA (50-200 μm) enhanced agonist-induced secretory responses in vitro and a metabolically stable UDCA analogue, 6α-methyl-UDCA, exerted anti-secretory actions in vitro and in vivo. In conclusion, UDCA exerts direct anti-secretory actions on colonic epithelial cells and metabolically stable derivatives of the bile acid may offer a new approach for treating intestinal diseases associated with diarrhoea.
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Affiliation(s)
- Orlaith B Kelly
- Department of Molecular Medicine, Royal College of Surgeons in Ireland, Dublin, Ireland
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13
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Butler AW, Breen G, Tozzi F, Craddock N, Gill M, Korszun A, Maier W, Middleton LT, Mors O, Owen MJ, Perry J, Preisig M, Rice JP, Rietschel M, Jones L, Farmer AE, Lewis CM, McGuffin P. A genomewide linkage study on suicidality in major depressive disorder confirms evidence for linkage to 2p12. Am J Med Genet B Neuropsychiatr Genet 2010; 153B:1465-73. [PMID: 20886545 DOI: 10.1002/ajmg.b.31127] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2010] [Accepted: 08/12/2010] [Indexed: 11/06/2022]
Abstract
Suicidal behavior is commonly associated with depression. Twin studies indicate that both suicidality and major depressive disorder (MDD) are heritable. However, epidemiological evidence suggests that the inheritance of suicidality is likely to be independent of the underlying psychiatric disorder, implying a distinct genetic contribution to suicidality. We conducted a genomewide linkage search aiming to detect genomic loci that may harbor susceptibility genes contributing to risk for suicidality in recurrent MDD. Affected sibling pair (ASP) variance components analysis was performed using the Depression Network cohort of 971 ASPs. The quantitative trait measuring suicidality as a broad phenotype, encompassing ideation and suicide attempts, was established from Schedules for Clinical Assessment in Neuropsychiatry interview items. We examined 1,060 genotyped microsatellite markers with an average spacing of 3.3 cM. Empirical thresholds for linkage evidence were set by whole-genome simulations (LOD = 2.71 for genomewide significance, 1.71 for suggestive linkage). No genomewide significant findings were found. Marker D3S1234 on 3p14 achieved suggestive linkage and yielded a maximum LOD of 1.853 (P = 0.0017), loci 9p24.3 and 18q22-q23 achieved LOD scores >1.5. We found some support for linkage to 2p12 (LOD = 1.2, P = 0.0087) which was previously implicated in linkage studies of suicidality. Our follow-up meta-analysis of five studies showed strong linkage to this region (P = 2 × 10(-6) ). In conclusion, this study analyzed suicidality as a continuous trait in MDD. We found modest evidence for linkage on 3p14. Our meta-analysis supports previous evidence of linkage to suicidality on 2p12. Some candidate genes in these regions may plausibly be implicated in suicidality. © 2010 Wiley-Liss, Inc.
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Affiliation(s)
- Amy W Butler
- MRC Social Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, King's College London, London, UK
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14
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Brignone MS, Lanciotti A, Macioce P, Macchia G, Gaetani M, Aloisi F, Petrucci TC, Ambrosini E. The beta1 subunit of the Na,K-ATPase pump interacts with megalencephalic leucoencephalopathy with subcortical cysts protein 1 (MLC1) in brain astrocytes: new insights into MLC pathogenesis. Hum Mol Genet 2010; 20:90-103. [PMID: 20926452 DOI: 10.1093/hmg/ddq435] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Megalencephalic leucoencephalopathy with subcortical cysts (MLC) is a rare congenital leucodystrophy caused by mutations in MLC1, a membrane protein of unknown function. MLC1 expression in astrocyte end-feet contacting blood vessels and meninges, along with brain swelling, fluid cysts and myelin vacuolation observed in MLC patients, suggests a possible role for MLC1 in the regulation of fluid and ion homeostasis and cellular volume changes. To identify MLC1 direct interactors and dissect the molecular pathways in which MLC1 is involved, we used NH2-MLC1 domain as a bait to screen a human brain library in a yeast two-hybrid assay. We identified the β1 subunit of the Na,K-ATPase pump as one of the interacting clones and confirmed it by pull-downs, co-fractionation assays and immunofluorescence stainings in human and rat astrocytes in vitro and in brain tissue. By performing ouabain-affinity chromatography on astrocyte and brain extracts, we isolated MLC1 and the whole Na,K-ATPase enzyme in a multiprotein complex that included Kir4.1, syntrophin and dystrobrevin. Because Na,K-ATPase is involved in intracellular osmotic control and volume regulation, we investigated the effect of hypo-osmotic stress on MLC1/Na,K-ATPase relationship in astrocytes. We found that hypo-osmotic conditions increased MLC1 membrane expression and favoured MLC1/Na,K-ATPase-β1 association. Moreover, hypo-osmosis induced astrocyte swelling and the reversible formation of endosome-derived vacuoles, where the two proteins co-localized. These data suggest that through its interaction with Na,K-ATPase, MLC1 is involved in the control of intracellular osmotic conditions and volume regulation in astrocytes, opening new perspectives for understanding the pathological mechanisms of MLC disease.
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Affiliation(s)
- Maria S Brignone
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità, Rome, Italy
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15
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Characterization of PXK as a protein involved in epidermal growth factor receptor trafficking. Mol Cell Biol 2010; 30:1689-702. [PMID: 20086096 DOI: 10.1128/mcb.01105-09] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The phox homology (PX) domain is a phosphoinositide-binding module that typically binds phosphatidylinositol 3-phosphate. Out of 47 mammalian proteins containing PX domains, more than 30 are denoted sorting nexins and several of these have been implicated in internalization of cell surface proteins to the endosome, where phosphatidylinositol-3-phosphate is concentrated. Here we investigated a multimodular protein termed PXK, composed of a PX domain, a protein kinase-like domain, and a WASP homology 2 domain. We show that the PX domain of PXK localizes this protein to the endosomal membrane via binding to phosphatidylinositol 3-phosphate. PXK expression in COS7 cells accelerated the ligand-induced internalization and degradation of epidermal growth factor receptors by a mechanism requiring phosphatidylinositol 3-phosphate binding but not involving the WASP homology 2 domain. Conversely, depletion of PXK using RNA interference decreased the rate of epidermal growth factor receptor internalization and degradation. Ubiquitination of epidermal growth factor receptor by the ligand stimulation was enhanced in PXK-expressing cells. These results indicate that PXK plays a critical role in epidermal growth factor receptor trafficking through modulating ligand-induced ubiquitination of the receptor.
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16
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Na,K-ATPase activity regulates AMPA receptor turnover through proteasome-mediated proteolysis. J Neurosci 2009; 29:4498-511. [PMID: 19357275 DOI: 10.1523/jneurosci.6094-08.2009] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Neuronal activity largely depends on two key components on the membrane: the Na,K-ATPase (NKA) that maintains the ion gradients and sets the foundation of excitability, and the ionotropic glutamatergic AMPA receptors (AMPARs) through which sodium influx forms the driving force for excitation. Because the frequent sodium transients from glutamate receptor activity need to be efficiently extruded, a functional coupling between NKA and AMPARs should be a necessary cellular device for synapse physiology. We show that NKA is enriched at synapses and associates with AMPARs. NKA dysfunction induces a rapid reduction in AMPAR cell-surface expression as well as total protein abundance, leading to a long-lasting depression in synaptic transmission. AMPAR proteolysis requires sodium influx, proteasomal activity and receptor internalization. These data elucidate a novel mechanism by which NKA regulates AMPAR turnover and thereby synaptic strength and brain function.
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Abstract
PURPOSE OF REVIEW Na,K-ATPase is an oligomeric protein composed of alpha subunits, beta subunits and FXYD proteins. The catalytic alpha subunit hydrolyzes ATP and transports the cations. Increasing experimental evidence suggest that beta subunits and FXYD proteins essentially contribute to the variable physiological needs of Na,K-ATPase function in different tissues. RECENT FINDINGS Beta subunits have a crucial role in the structural and functional maturation of Na,K-ATPase and modulate its transport properties. The chaperone function of the beta subunit is essential, for example, in the formation of tight junctions and cell polarity. Recent studies suggest that beta subunits also have inherent functions, which are independent of Na,K-ATPase activity and which may be involved in cell-cell adhesiveness and in suppression of cell motility. As for FXYD proteins, they modulate Na,K-ATPase activity in a tissue-specific way, in some cases in close cooperation with posttranslational modifications such as phosphorylation. SUMMARY A better understanding of the multiple functional roles of the accessory subunits of Na,K-ATPase is crucial to appraise their influence on physiological processes and their implication in pathophysiological states.
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von Schantz C, Saharinen J, Kopra O, Cooper JD, Gentile M, Hovatta I, Peltonen L, Jalanko A. Brain gene expression profiles of Cln1 and Cln5 deficient mice unravels common molecular pathways underlying neuronal degeneration in NCL diseases. BMC Genomics 2008; 9:146. [PMID: 18371231 PMCID: PMC2323392 DOI: 10.1186/1471-2164-9-146] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2007] [Accepted: 03/28/2008] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND The neuronal ceroid lipofuscinoses (NCL) are a group of children's inherited neurodegenerative disorders, characterized by blindness, early dementia and pronounced cortical atrophy. The similar pathological and clinical profiles of the different forms of NCL suggest that common disease mechanisms may be involved. To explore the NCL-associated disease pathology and molecular pathways, we have previously produced targeted knock-out mice for Cln1 and Cln5. Both mouse-models replicate the NCL phenotype and neuropathology; the Cln1-/- model presents with early onset, severe neurodegenerative disease, whereas the Cln5-/- model produces a milder disease with a later onset. RESULTS Here we have performed quantitative gene expression profiling of the cortex from 1 and 4 month old Cln1-/- and Cln5-/- mice. Combined microarray datasets from both mouse models exposed a common affected pathway: genes regulating neuronal growth cone stabilization display similar aberrations in both models. We analyzed locus specific gene expression and showed regional clustering of Cln1 and three major genes of this pathway, further supporting a close functional relationship between the corresponding gene products; adenylate cyclase-associated protein 1 (Cap1), protein tyrosine phosphatase receptor type F (Ptprf) and protein tyrosine phosphatase 4a2 (Ptp4a2). The evidence from the gene expression data, indicating changes in the growth cone assembly, was substantiated by the immunofluorescence staining patterns of Cln1-/- and Cln5-/- cortical neurons. These primary neurons displayed abnormalities in cytoskeleton-associated proteins actin and beta-tubulin as well as abnormal intracellular distribution of growth cone associated proteins GAP-43, synapsin and Rab3. CONCLUSION Our data provide the first evidence for a common molecular pathogenesis behind neuronal degeneration in INCL and vLINCL. Since CLN1 and CLN5 code for proteins with distinct functional roles these data may have implications for other forms of NCLs as well.
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Affiliation(s)
- Carina von Schantz
- National Public Health Institute and FIMM, Institute for Molecular Medicine, Helsinki, Finland
| | - Juha Saharinen
- National Public Health Institute and FIMM, Institute for Molecular Medicine, Helsinki, Finland
- Genome Informatics Unit, University of Helsinki, Finland
| | - Outi Kopra
- National Public Health Institute and FIMM, Institute for Molecular Medicine, Helsinki, Finland
- Folkhälsan Institute of Genetics, Helsinki, Finland
- Neuroscience Center, University of Helsinki, Finland
| | | | | | - Iiris Hovatta
- National Public Health Institute and FIMM, Institute for Molecular Medicine, Helsinki, Finland
- University of Helsinki, Department of Medical Genetics and Research Program of Molecular Neurology, Biomedicum Helsinki, Finland
| | - Leena Peltonen
- National Public Health Institute and FIMM, Institute for Molecular Medicine, Helsinki, Finland
- University of Helsinki, Department of Medical Genetics and Research Programme of Molecular Medicine, Biomedicum Helsinki, Finland
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SA, UK
| | - Anu Jalanko
- National Public Health Institute and FIMM, Institute for Molecular Medicine, Helsinki, Finland
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Characterization of NKIP: a novel, Na+/K+-ATPase interacting protein mediates neural differentiation and apoptosis. Exp Cell Res 2007; 314:463-77. [PMID: 18096156 DOI: 10.1016/j.yexcr.2007.11.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2007] [Revised: 11/05/2007] [Accepted: 11/08/2007] [Indexed: 01/17/2023]
Abstract
Cellular differentiation and programmed cell death are tightly controlled to maintain tissue homeostasis and proper organ function. In a screen for apoptosis specific gene products, we isolated an immediate early apoptosis response gene from myelomonocytic stem cells that appears to play a key regulatory role in a number of cell types and may be of particular importance in cells of the central nervous system. The gene's 28 kDa protein product interacts with the C-terminal ectodomain of the Na+/K+-ATPase (NKA) beta 1 subunit and was therefore named NKIP (NKA Interacting Protein). NKIP is coexpressed with NKA, localizes to lysosomes and the endoplasmic reticulum and is predominantly expressed in excitable tissues including polarized epithelia and the central nervous system. NKIP has been characterized as an endogenous suppressor of the NKA as reduction of NKIP in PC12 cells significantly increases NKA activity. In pluripotent NT2 progenitor cells, NKIP induced rapidly K+-level-dependent cell death. NKIP overexpression induced growth factor-independent neurite outgrowth, which was associated with MEK-independent phosphorylation of the transcription factor ERK1/2. Thus, we have identified NKIP as an important novel protein that interacts to the NKA complex, influencing cellular ion balance, induction of apoptosis and neuronal differentiation.
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20
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Gorokhova S, Bibert S, Geering K, Heintz N. A novel family of transmembrane proteins interacting with beta subunits of the Na,K-ATPase. Hum Mol Genet 2007; 16:2394-410. [PMID: 17606467 DOI: 10.1093/hmg/ddm167] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
We characterized a family consisting of four mammalian proteins of unknown function (NKAIN1, 2, 3 and 4) and a single Drosophila ortholog dNKAIN. Aside from highly conserved transmembrane domains, NKAIN proteins contain no characterized functional domains. Striking amino acid conservation in the first two transmembrane domains suggests that these proteins are likely to function within the membrane bilayer. NKAIN family members are neuronally expressed in multiple regions of the mouse brain, although their expression is not ubiquitous. We demonstrate that mouse NKAIN1 interacts with the beta1 subunit of the Na,K-ATPase, whereas Drosophila ortholog dNKAIN interacts with Nrv2.2, a Drosophila homolog of the Na,K-ATPase beta subunits. We also show that NKAIN1 can form a complex with another beta subunit-binding protein, MONaKA, when binding to the beta1 subunit of the Na,K-ATPase. Our results suggest that a complex between mammalian NKAIN1 and MONaKA is required for NKAIN function, which is carried out by a single protein, dNKAIN, in Drosophila. This hypothesis is supported by the fact that dNKAIN, but not NKAIN1, induces voltage-independent amiloride-insensitive Na(+)-specific conductance that can be blocked by lanthanum. Drosophila mutants with decreased dNKAIN expression due to a P-element insertion in the dNKAIN gene exhibit temperature-sensitive paralysis, a phenotype also caused by mutations in the Na,K-ATPase alpha subunit and several ion channels. The neuronal expression of NKAIN proteins, their membrane localization and the temperature-sensitive paralysis of NKAIN Drosophila mutants strongly suggest that this novel protein family may be critical for neuronal function.
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Affiliation(s)
- Svetlana Gorokhova
- Laboratory of Molecular Biology, Howard Hughes Medical Institute, The Rockefeller University, New York, NY 10021, USA
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21
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Li Y, Wu Y, Zhou Y. Modulation of inactivation properties of CaV2.2 channels by 14-3-3 proteins. Neuron 2006; 51:755-71. [PMID: 16982421 DOI: 10.1016/j.neuron.2006.08.014] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2005] [Revised: 05/08/2006] [Accepted: 08/08/2006] [Indexed: 11/28/2022]
Abstract
Inactivation of presynaptic Ca(V)2.2 channels may play a role in regulating short-term synaptic plasticity. Here, we report a direct modulation of Ca(V)2.2 channel inactivation properties by 14-3-3, a family of signaling proteins involved in a wide range of biological processes. The structural elements critical for 14-3-3 binding and channel modulation lie in the carboxyl tail of the pore-forming alpha(1B) subunit, where we have identified two putative 14-3-3 interaction sites, including a phosphoserine-containing motif that directly binds to 14-3-3 and a second region near the EF hand and IQ domain. In transfected tsA 201 cells, 14-3-3 coexpression dramatically slows open-state inactivation and reduces cumulative inactivation of Ca(V)2.2 channels. In hippocampal neurons, interference with 14-3-3 binding accelerates Ca(V)2.2 channel inactivation and enhances short-term synaptic depression. These results demonstrate that 14-3-3 proteins are important regulators of Ca(V)2.2 channel activities and through this mechanism may contribute to their regulation of synaptic transmission and plasticity.
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MESH Headings
- 14-3-3 Proteins/genetics
- 14-3-3 Proteins/metabolism
- 14-3-3 Proteins/physiology
- Amino Acid Sequence
- Animals
- Binding Sites/genetics
- Binding, Competitive
- Blotting, Western
- Brain/cytology
- Brain/metabolism
- Calcium Channels, L-Type/genetics
- Calcium Channels, L-Type/metabolism
- Calcium Channels, N-Type/genetics
- Calcium Channels, N-Type/metabolism
- Calcium Channels, T-Type/genetics
- Calcium Channels, T-Type/metabolism
- Cell Line
- Cells, Cultured
- Glutathione Transferase/genetics
- Glutathione Transferase/metabolism
- Humans
- Neurons/cytology
- Neurons/metabolism
- Phosphorylation
- Protein Binding
- Protein Subunits/genetics
- Protein Subunits/metabolism
- Rats
- Rats, Sprague-Dawley
- Recombinant Fusion Proteins/genetics
- Recombinant Fusion Proteins/metabolism
- Synaptic Transmission/physiology
- Time Factors
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Affiliation(s)
- Yong Li
- Department of Neurobiology, Evelyn F. McKnight Brain Institute and Civitan International Research Center, School of Medicine, University of Alabama at Birmingham, 35294, USA
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