1
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Zhang X, Lee W, Bian JS. Recent Advances in the Study of Na +/K +-ATPase in Neurodegenerative Diseases. Cells 2022; 11:cells11244075. [PMID: 36552839 PMCID: PMC9777075 DOI: 10.3390/cells11244075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2022] [Revised: 12/11/2022] [Accepted: 12/13/2022] [Indexed: 12/23/2022] Open
Abstract
Na+/K+-ATPase (NKA), a large transmembrane protein, is expressed in the plasma membrane of most eukaryotic cells. It maintains resting membrane potential, cell volume and secondary transcellular transport of other ions and neurotransmitters. NKA consumes about half of the ATP molecules in the brain, which makes NKA highly sensitive to energy deficiency. Neurodegenerative diseases (NDDs) are a group of diseases characterized by chronic, progressive and irreversible neuronal loss in specific brain areas. The pathogenesis of NDDs is sophisticated, involving protein misfolding and aggregation, mitochondrial dysfunction and oxidative stress. The protective effect of NKA against NDDs has been emerging gradually in the past few decades. Hence, understanding the role of NKA in NDDs is critical for elucidating the underlying pathophysiology of NDDs and identifying new therapeutic targets. The present review focuses on the recent progress involving different aspects of NKA in cellular homeostasis to present in-depth understanding of this unique protein. Moreover, the essential roles of NKA in NDDs are discussed to provide a platform and bright future for the improvement of clinical research in NDDs.
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Affiliation(s)
- Xiaoyan Zhang
- Department of Pharmacology, School of Medicine, Southern University of Science and Technology, Shenzhen 518055, China
| | - Weithye Lee
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117600, Singapore
| | - Jin-Song Bian
- Department of Pharmacology, School of Medicine, Southern University of Science and Technology, Shenzhen 518055, China
- Correspondence:
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2
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Roldán ML, Ramírez-Salinas GL, Martinez-Archundia M, Cuellar-Perez F, Vilchis-Nestor CA, Cancino-Diaz JC, Shoshani L. The β2-Subunit (AMOG) of Human Na+, K+-ATPase Is a Homophilic Adhesion Molecule. Int J Mol Sci 2022; 23:ijms23147753. [PMID: 35887102 PMCID: PMC9322774 DOI: 10.3390/ijms23147753] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 07/05/2022] [Accepted: 07/05/2022] [Indexed: 12/10/2022] Open
Abstract
The β2 subunit of Na+, K+-ATPase was originally identified as the adhesion molecule on glia (AMOG) that mediates the adhesion of astrocytes to neurons in the central nervous system and that is implicated in the regulation of neurite outgrowth and neuronal migration. While β1 isoform have been shown to trans-interact in a species-specific mode with the β1 subunit on the epithelial neighboring cell, the β2 subunit has been shown to act as a recognition molecule on the glia. Nevertheless, none of the works have identified the binding partner of β2 or described its adhesion mechanism. Until now, the interactions pronounced for β2/AMOG are heterophilic cis-interactions. In the present report we designed experiments that would clarify whether β2 is a cell–cell homophilic adhesion molecule. For this purpose, we performed protein docking analysis, cell–cell aggregation, and protein–protein interaction assays. We observed that the glycosylated extracellular domain of β2/AMOG can make an energetically stable trans-interacting dimer. We show that CHO (Chinese Hamster Ovary) fibroblasts transfected with the human β2 subunit become more adhesive and make large aggregates. The treatment with Tunicamycin in vivo reduced cell aggregation, suggesting the participation of N-glycans in that process. Protein–protein interaction assay in vivo with MDCK (Madin-Darby canine kidney) or CHO cells expressing a recombinant β2 subunit show that the β2 subunits on the cell surface of the transfected cell lines interact with each other. Overall, our results suggest that the human β2 subunit can form trans-dimers between neighboring cells when expressed in non-astrocytic cells, such as fibroblasts (CHO) and epithelial cells (MDCK).
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Affiliation(s)
- María Luisa Roldán
- Department of Physiology, Biophysics and Neurosciences, CINVESTAV-IPN, 2508 IPN Ave., San Pedro Zacatenco, Ciudad de México 07360, Mexico; (M.L.R.); (F.C.-P.); (C.A.V.-N.)
| | - Gema Lizbeth Ramírez-Salinas
- Department of Immunology, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México (UNAM), Circuito, Mario de La Cueva S/N, C.U., Coyoacán, Ciudad de México 04510, Mexico;
| | - Marlet Martinez-Archundia
- Laboratorio de Modelado Molecular, Bioinformática y Diseño de Fármacos, Departamento de Posgrado Escuela Superior de Medicina del Instituto Politécnico Nacional, Salvador Díaz Mirón esq. Plan de San Luis S/N, Miguel Hidalgo, Casco de Santo Tomas, Ciudad de México 11340, Mexico;
| | - Francisco Cuellar-Perez
- Department of Physiology, Biophysics and Neurosciences, CINVESTAV-IPN, 2508 IPN Ave., San Pedro Zacatenco, Ciudad de México 07360, Mexico; (M.L.R.); (F.C.-P.); (C.A.V.-N.)
| | - Claudia Andrea Vilchis-Nestor
- Department of Physiology, Biophysics and Neurosciences, CINVESTAV-IPN, 2508 IPN Ave., San Pedro Zacatenco, Ciudad de México 07360, Mexico; (M.L.R.); (F.C.-P.); (C.A.V.-N.)
| | - Juan Carlos Cancino-Diaz
- Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas del Instituto Politécnico Nacional, Salvador Díaz Mirón esq. Plan de San Luis S/N, Miguel Hidalgo, Casco de Santo Tomas, Ciudad de México 11340, Mexico;
| | - Liora Shoshani
- Department of Physiology, Biophysics and Neurosciences, CINVESTAV-IPN, 2508 IPN Ave., San Pedro Zacatenco, Ciudad de México 07360, Mexico; (M.L.R.); (F.C.-P.); (C.A.V.-N.)
- Correspondence: ; Tel.: +52-55-5747-3360
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3
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Kryvenko V, Vagin O, Dada LA, Sznajder JI, Vadász I. Maturation of the Na,K-ATPase in the Endoplasmic Reticulum in Health and Disease. J Membr Biol 2021; 254:447-457. [PMID: 34114062 PMCID: PMC8192048 DOI: 10.1007/s00232-021-00184-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Accepted: 05/08/2021] [Indexed: 12/11/2022]
Abstract
Abstract The Na,K-ATPase establishes the electrochemical gradient of cells by driving an active exchange of Na+ and K+ ions while consuming ATP. The minimal functional transporter consists of a catalytic α-subunit and a β-subunit with chaperon activity. The Na,K-ATPase also functions as a cell adhesion molecule and participates in various intracellular signaling pathways. The maturation and trafficking of the Na,K-ATPase include co- and post-translational processing of the enzyme in the endoplasmic reticulum (ER) and the Golgi apparatus and subsequent delivery to the plasma membrane (PM). The ER folding of the enzyme is considered as the rate-limiting step in the membrane delivery of the protein. It has been demonstrated that only assembled Na,K-ATPase α:β-complexes may exit the organelle, whereas unassembled, misfolded or unfolded subunits are retained in the ER and are subsequently degraded. Loss of function of the Na,K-ATPase has been associated with lung, heart, kidney and neurological disorders. Recently, it has been shown that ER dysfunction, in particular, alterations in the homeostasis of the organelle, as well as impaired ER-resident chaperone activity may impede folding of Na,K-ATPase subunits, thus decreasing the abundance and function of the enzyme at the PM. Here, we summarize our current understanding on maturation and subsequent processing of the Na,K-ATPase in the ER under physiological and pathophysiological conditions. Graphic Abstract ![]()
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Affiliation(s)
- Vitalii Kryvenko
- Department of Internal Medicine, Universities of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Justus Liebig University, Klinikstrasse 33, 35392, Giessen, Germany.,The Cardio-Pulmonary Institute (CPI), Giessen, Germany
| | - Olga Vagin
- Department of Physiology, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA, USA.,Veterans Administration Greater Los Angeles Healthcare System, Los Angeles, CA, USA
| | - Laura A Dada
- Division of Pulmonary and Critical Care Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Jacob I Sznajder
- Division of Pulmonary and Critical Care Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - István Vadász
- Department of Internal Medicine, Universities of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Justus Liebig University, Klinikstrasse 33, 35392, Giessen, Germany. .,The Cardio-Pulmonary Institute (CPI), Giessen, Germany.
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4
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Guo H, Yin A, Ma Y, Fan Z, Tao L, Tang W, Ma Y, Hou W, Cai G, Zhuo L, Zhang J, Li Y, Xiong L. Astroglial N-myc downstream-regulated gene 2 protects the brain from cerebral edema induced by stroke. Glia 2020; 69:281-295. [PMID: 32652708 PMCID: PMC7754347 DOI: 10.1002/glia.23888] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Revised: 06/16/2020] [Accepted: 06/26/2020] [Indexed: 01/14/2023]
Abstract
Brain edema is a grave complication of brain ischemia and is the main cause of herniation and death. Although astrocytic swelling is the main contributor to cytotoxic edema, the molecular mechanism involved in this process remains elusive. N‐myc downstream‐regulated gene 2 (NDRG2), a well‐studied tumor suppressor gene, is mainly expressed in astrocytes in mammalian brains. Here, we found that NDRG2 deficiency leads to worsened cerebral edema, imbalanced Na+ transfer, and astrocyte swelling after ischemia. We also found that NDRG2 deletion in astrocytes dramatically changed the expression and distribution of aquaporin‐4 and Na+‐K+‐ATPase β1, which are strongly associated with cell polarity, in the ischemic brain. Brain edema and astrocyte swelling were significantly alleviated by rescuing the expression of astrocytic Na+‐K+‐ATPase β1 in NDRG2‐knockout mouse brains. In addition, the upregulation of astrocytic NDRG2 by lentiviral constructs notably attenuated brain edema, astrocytic swelling, and blood–brain barrier destruction. Our results indicate a particular role of NDRG2 in maintaining astrocytic polarization to facilitate Na+ and water transfer balance and to protect the brain from ischemic edema. These findings provide insight into NDRG2 as a therapeutic target in cerebral edema.
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Affiliation(s)
- Hang Guo
- Department of Anesthesiology, The Seventh Medical Center of Chinese PLA General Hospital, Beijing, China.,Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, The Air Force Military Medical University, Xi'an, China
| | - Anqi Yin
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, The Air Force Military Medical University, Xi'an, China.,Department of Anesthesiology, Jinling Hospital, Nanjing, China
| | - Yulong Ma
- Anesthesia and Operation Center, The First Medical Center of Chinese PLA General Hospital, Beijing, China
| | - Ze Fan
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, The Air Force Military Medical University, Xi'an, China
| | - Liang Tao
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, The Air Force Military Medical University, Xi'an, China
| | - Wenhong Tang
- Department of Anesthesiology, The 960th Hospital of PLA, Jinan, China
| | - Yaqun Ma
- Department of Anesthesiology, The Seventh Medical Center of Chinese PLA General Hospital, Beijing, China
| | - Wugang Hou
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, The Air Force Military Medical University, Xi'an, China
| | - Guohong Cai
- Institute of Neuroscience, The Air Force Military Medical University, Xi'an, China
| | - Lixia Zhuo
- Department of Anesthesiology & Center for Brain Science, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Jian Zhang
- Department of Biochemistry and Molecular Biology, The Air Force Military Medical University, Xi'an, China
| | - Yan Li
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, The Air Force Military Medical University, Xi'an, China.,Department of Anesthesiology & Center for Brain Science, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Lize Xiong
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, The Air Force Military Medical University, Xi'an, China.,Department of Anesthesiology & Translational Research Institute of Brain and Brain-Like Intelligence, Shanghai Fourth People's Hospital, Tongji University School of Medicine, Shanghai, China
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5
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Marcus EA, Tokhtaeva E, Jimenez JL, Wen Y, Naini BV, Heard AN, Kim S, Capri J, Cohn W, Whitelegge JP, Vagin O. Helicobacter pylori infection impairs chaperone-assisted maturation of Na-K-ATPase in gastric epithelium. Am J Physiol Gastrointest Liver Physiol 2020; 318:G931-G945. [PMID: 32174134 PMCID: PMC7272721 DOI: 10.1152/ajpgi.00266.2019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Helicobacter pylori infection always induces gastritis, which may progress to ulcer disease or cancer. The mechanisms underlying mucosal injury by the bacteria are incompletely understood. Here, we identify a novel pathway for H. pylori-induced gastric injury, the impairment of maturation of the essential transport enzyme and cell adhesion molecule, Na-K-ATPase. Na-K-ATPase comprises α- and β-subunits that assemble in the endoplasmic reticulum (ER) before trafficking to the plasma membrane. Attachment of H. pylori to gastric epithelial cells increased Na-K-ATPase ubiquitylation, decreased its surface and total levels, and impaired ion balance. H. pylori did not alter degradation of plasmalemma-resident Na-K-ATPase subunits or their mRNA levels. Infection decreased association of α- and β-subunits with ER chaperone BiP and impaired assembly of α/β-heterodimers, as was revealed by quantitative mass spectrometry and immunoblotting of immunoprecipitated complexes. The total level of BiP was not altered, and the decrease in interaction with BiP was not observed for other BiP client proteins. The H. pylori-induced decrease in Na-K-ATPase was prevented by BiP overexpression, stopping protein synthesis, or inhibiting proteasomal, but not lysosomal, protein degradation. The results indicate that H. pylori impairs chaperone-assisted maturation of newly made Na-K-ATPase subunits in the ER independently of a generalized ER stress and induces their ubiquitylation and proteasomal degradation. The decrease in Na-K-ATPase levels is also seen in vivo in the stomachs of gerbils and chronically infected children. Further understanding of H. pylori-induced Na-K-ATPase degradation will provide insights for protection against advanced disease.NEW & NOTEWORTHY This work provides evidence that Helicobacter pylori decreases levels of Na-K-ATPase, a vital transport enzyme, in gastric epithelia, both in acutely infected cultured cells and in chronically infected patients and animals. The bacteria interfere with BiP-assisted folding of newly-made Na-K-ATPase subunits in the endoplasmic reticulum, accelerating their ubiquitylation and proteasomal degradation and decreasing efficiency of the assembly of native enzyme. Decreased Na-K-ATPase expression contributes to H. pylori-induced gastric injury.
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Affiliation(s)
- Elizabeth A. Marcus
- 1Department of Pediatrics, David Geffen School of Medicine, University of California, Los Angeles, California,4Veterans Affairs Greater Los Angeles Health Care System, Los Angeles, California
| | - Elmira Tokhtaeva
- 2Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, California,4Veterans Affairs Greater Los Angeles Health Care System, Los Angeles, California
| | - Jossue L. Jimenez
- 1Department of Pediatrics, David Geffen School of Medicine, University of California, Los Angeles, California,4Veterans Affairs Greater Los Angeles Health Care System, Los Angeles, California
| | - Yi Wen
- 2Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, California,4Veterans Affairs Greater Los Angeles Health Care System, Los Angeles, California
| | - Bita V. Naini
- 3Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California, Los Angeles, California
| | - Ashley N. Heard
- 1Department of Pediatrics, David Geffen School of Medicine, University of California, Los Angeles, California,4Veterans Affairs Greater Los Angeles Health Care System, Los Angeles, California
| | - Samuel Kim
- 4Veterans Affairs Greater Los Angeles Health Care System, Los Angeles, California
| | - Joseph Capri
- 5Pasarow Mass Spectrometry Laboratory, The Neuropsychiatric Insititute–Semel Institute, University of California, Los Angeles, California
| | - Whitaker Cohn
- 5Pasarow Mass Spectrometry Laboratory, The Neuropsychiatric Insititute–Semel Institute, University of California, Los Angeles, California
| | - Julian P. Whitelegge
- 5Pasarow Mass Spectrometry Laboratory, The Neuropsychiatric Insititute–Semel Institute, University of California, Los Angeles, California
| | - Olga Vagin
- 2Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, California,4Veterans Affairs Greater Los Angeles Health Care System, Los Angeles, California
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6
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Gomez-Acevedo H, Dai Y, Strub G, Shawber C, Wu JK, Richter GT. Identification of putative biomarkers for Infantile Hemangiomas and Propranolol treatment via data integration. Sci Rep 2020; 10:3261. [PMID: 32094357 PMCID: PMC7039967 DOI: 10.1038/s41598-020-60025-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 12/20/2019] [Indexed: 12/29/2022] Open
Abstract
Infantile hemangiomas (IHs) are the most common benign tumors in early childhood. They show a distinctive mechanism of tumor growth in which a rapid proliferative phase is followed by a regression phase (involution). Propranolol is an approved treatment for IHs, but its mechanism of action remains unclear. We integrated and harmonized microRNA and mRNA transcriptome data from newly generated microarray data on IHs with publicly available data on toxicological transcriptomics from propranolol exposure, and with microRNA data from IHs and propranolol exposure. We identified subsets of putative biomarkers for proliferation and involution as well as a small set of putative biomarkers for propranolol's mechanism of action for IHs, namely EPAS1, LASP1, SLC25A23, MYO1B, and ALDH1A1. Based on our integrative data approach and confirmatory experiments, we concluded that hypoxia in IHs is regulated by EPAS1 (HIF-2α) instead of HIF-1α, and also that propranolol-induced apoptosis in endothelial cells may occur via mitochondrial stress.
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Affiliation(s)
- Horacio Gomez-Acevedo
- Department of Biomedical Informatics, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA.
| | - Yuemeng Dai
- Mesquite Rehabilitation Institute, Mesquite, Texas, USA
| | - Graham Strub
- Department of Otolaryngology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Carrie Shawber
- Department of Surgery, New York-Presbyterian/Morgan Stanley Children's Hospital, Columbia University, New York, New York, USA
| | - June K Wu
- Department of Reproductive Sciences in Obstetrics & Gynecology and Surgery, Columbia University, New York, New York, USA
| | - Gresham T Richter
- Department of Otolaryngology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
- Arkansas Children's Hospital, Little Rock, Arkansas, USA
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7
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A Model for the Homotypic Interaction between Na +,K +-ATPase β 1 Subunits Reveals the Role of Extracellular Residues 221-229 in Its Ig-Like Domain. Int J Mol Sci 2019; 20:ijms20184538. [PMID: 31540261 PMCID: PMC6770782 DOI: 10.3390/ijms20184538] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 08/13/2019] [Accepted: 08/16/2019] [Indexed: 12/15/2022] Open
Abstract
The Na+, K+-ATPase transports Na+ and K+ across the membrane of all animal cells. In addition to its ion transporting function, the Na+, K+-ATPase acts as a homotypic epithelial cell adhesion molecule via its β1 subunit. The extracellular region of the Na+, K+-ATPase β1 subunit includes a single globular immunoglobulin-like domain. We performed Molecular Dynamics simulations of the ectodomain of the β1 subunit and a refined protein-protein docking prediction. Our results show that the β1 subunit Ig-like domain maintains an independent structure and dimerizes in an antiparallel fashion. Analysis of the putative interface identified segment Lys221-Tyr229. We generated triple mutations on YFP-β1 subunit fusion proteins to assess the contribution of these residues. CHO fibroblasts transfected with mutant β1 subunits showed a significantly decreased cell-cell adhesion. Association of β1 subunits in vitro was also reduced, as determined by pull-down assays. Altogether, we conclude that two Na+, K+-ATPase molecules recognize each other by a large interface spanning residues 221–229 and 198–207 on their β1 subunits.
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8
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Litan A, Li Z, Tokhtaeva E, Kelly P, Vagin O, Langhans SA. A Functional Interaction Between Na,K-ATPase β 2-Subunit/AMOG and NF2/Merlin Regulates Growth Factor Signaling in Cerebellar Granule Cells. Mol Neurobiol 2019; 56:7557-7571. [PMID: 31062247 DOI: 10.1007/s12035-019-1592-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Accepted: 04/02/2019] [Indexed: 10/26/2022]
Abstract
The Na,K-ATPase, consisting of a catalytic α-subunit and a regulatory β-subunit, is a ubiquitously expressed ion pump that carries out the transport of Na+ and K+ across the plasma membranes of most animal cells. In addition to its pump function, Na,K-ATPase serves as a signaling scaffold and a cell adhesion molecule. Of the three β-subunit isoforms, β1 is found in almost all tissues, while β2 expression is mostly restricted to brain and muscle. In cerebellar granule cells, the β2-subunit, also known as adhesion molecule on glia (AMOG), has been linked to neuron-astrocyte adhesion and granule cell migration, suggesting its role in cerebellar development. Nevertheless, little is known about molecular pathways that link the β2-subunit to its cellular functions. Using cerebellar granule precursor cells, we found that the β2-subunit, but not the β1-subunit, negatively regulates the expression of a key activator of the Hippo/YAP signaling pathway, Merlin/neurofibromin-2 (NF2). The knockdown of the β2-subunit resulted in increased Merlin/NF2 expression and affected downstream targets of Hippo signaling, i.e., increased YAP phosphorylation and decreased expression of N-Ras. Further, the β2-subunit knockdown altered the kinetics of epidermal growth factor receptor (EGFR) signaling in a Merlin-dependent mode and impaired EGF-induced reorganization of the actin cytoskeleton. Therefore, our studies for the first time provide a functional link between the Na,K-ATPase β2-subunit and Merlin/NF2 and suggest a role for the β2-subunit in regulating cytoskeletal dynamics and Hippo/YAP signaling during neuronal differentiation.
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Affiliation(s)
- Alisa Litan
- Nemours Biomedical Research, Alfred I. duPont Hospital for Children, DuPont Experimental Station, Bldg 400, #4414, 200 Powder Mill Road, Wilmington, DE, 19803, USA.,Biological Sciences Graduate Program, University of Delaware, Newark, DE, 19716, USA
| | - Zhiqin Li
- Nemours Biomedical Research, Alfred I. duPont Hospital for Children, DuPont Experimental Station, Bldg 400, #4414, 200 Powder Mill Road, Wilmington, DE, 19803, USA
| | - Elmira Tokhtaeva
- David Geffen School of Medicine, University of California, Los Angeles, and VA Greater Los Angeles Health Care System, Los Angeles, CA, 90073, USA
| | - Patience Kelly
- Nemours Biomedical Research, Alfred I. duPont Hospital for Children, DuPont Experimental Station, Bldg 400, #4414, 200 Powder Mill Road, Wilmington, DE, 19803, USA.,Biological Sciences Graduate Program, University of Delaware, Newark, DE, 19716, USA
| | - Olga Vagin
- David Geffen School of Medicine, University of California, Los Angeles, and VA Greater Los Angeles Health Care System, Los Angeles, CA, 90073, USA
| | - Sigrid A Langhans
- Nemours Biomedical Research, Alfred I. duPont Hospital for Children, DuPont Experimental Station, Bldg 400, #4414, 200 Powder Mill Road, Wilmington, DE, 19803, USA.
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9
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Ouabain Accelerates Collective Cell Migration Through a cSrc and ERK1/2 Sensitive Metalloproteinase Activity. J Membr Biol 2019; 252:549-559. [PMID: 31041466 DOI: 10.1007/s00232-019-00066-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Accepted: 04/17/2019] [Indexed: 10/26/2022]
Abstract
Studies made in the Madin-Darby canine kidney (MDCK) epithelial cell line showed that ouabain regulates cell adhesion and cell-adhesion-related biological processes, such as migration. Here, we demonstrated that 10 nM ouabain accelerates collective cell migration and heals wounds in cultured MDCK cell monolayers. Ouabain-induced acceleration of cell migration depends on activation of the cSrc-ERK1/2 signaling cascade, as it was inhibited by the kinase inhibitors PP2 and PD98059. Activation of the cSrc-ERK1/2 signaling cascade increased expression and activation of the extracellular matrix metalloproteinase-2 (MMP-2). Inhibition of MMP activity using the generic inhibitor GM6001 or the potent iMMP-2 inhibitor prevented the accelerative effect of ouabain. Likewise, Focal Adhesion Kinase (FAK) inhibition with the transfection of dominant negative peptide FRNK impaired the effect of ouabain. These results suggest that ouabain binding to the Na+,K+-ATPase accelerates collective migration of MDCK cells through activation of the cSrc-ERK1/2-FAK signaling cascade and promoting secretion and MMP activity.
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10
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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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11
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Lubarski-Gotliv I, Dey K, Kuznetsov Y, Kalchenco V, Asher C, Garty H. FXYD5 (dysadherin) may mediate metastatic progression through regulation of the β-Na+-K+-ATPase subunit in the 4T1 mouse breast cancer model. Am J Physiol Cell Physiol 2017; 313:C108-C117. [DOI: 10.1152/ajpcell.00206.2016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 04/24/2017] [Accepted: 05/06/2017] [Indexed: 11/22/2022]
Abstract
FXYD5 is a Na+-K+-ATPase regulator, expressed in a variety of normal epithelia. In parallel, it has been found to be associated with several types of cancer and effect lethal outcome by promoting metastasis. However, the molecular mechanism underlying FXYD5 mediated invasion has not yet been identified. In this study, using in vivo 4T1 murine breast cancer model, we found that FXYD5-specific shRNA significantly inhibited lung cancer metastasis, without having a substantial effect on primary tumor growth. Our study reveals that FXYD5 participates in multiple stages of metastatic development and exhibits more than one mode of E-cadherin regulation. We provide the first evidence that FXYD5-related morphological changes are mediated through its interaction with Na+-K+-ATPase. Experiments in cultured 4T1 cells have indicated that FXYD5 expression may downregulate the β1 isoform of the pump. This behavior could have implications on both transcellular interactions and intracellular events. Further studies suggest that differential localization of the adaptor protein Annexin A2 in FXYD5-expressing cells may correlate with matrix metalloproteinase 9 secretion and adhesion changes in 4T1 wild-type cells.
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Affiliation(s)
- Irina Lubarski-Gotliv
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot, Israel; and
| | - Kuntal Dey
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot, Israel; and
| | - Yuri Kuznetsov
- Department of Veterinary Resources, Weizmann Institute of Science, Rehovot, Israel
| | - Vecheslav Kalchenco
- Department of Veterinary Resources, Weizmann Institute of Science, Rehovot, Israel
| | - Carol Asher
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot, Israel; and
| | - Haim Garty
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot, Israel; and
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12
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Tokhtaeva E, Sun H, Deiss-Yehiely N, Wen Y, Soni PN, Gabrielli NM, Marcus EA, Ridge KM, Sachs G, Vazquez-Levin M, Sznajder JI, Vagin O, Dada LA. The O-glycosylated ectodomain of FXYD5 impairs adhesion by disrupting cell-cell trans-dimerization of Na,K-ATPase β1 subunits. J Cell Sci 2016; 129:2394-406. [PMID: 27142834 DOI: 10.1242/jcs.186148] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Accepted: 04/26/2016] [Indexed: 12/24/2022] Open
Abstract
FXYD5 (also known as dysadherin), a regulatory subunit of the Na,K-ATPase, impairs intercellular adhesion by a poorly understood mechanism. Here, we determined whether FXYD5 disrupts the trans-dimerization of Na,K-ATPase molecules located in neighboring cells. Mutagenesis of the Na,K-ATPase β1 subunit identified four conserved residues, including Y199, that are crucial for the intercellular Na,K-ATPase trans-dimerization and adhesion. Modulation of expression of FXYD5 or of the β1 subunit with intact or mutated β1-β1 binding sites demonstrated that the anti-adhesive effect of FXYD5 depends on the presence of Y199 in the β1 subunit. Immunodetection of the plasma membrane FXYD5 was prevented by the presence of O-glycans. Partial FXYD5 deglycosylation enabled antibody binding and showed that the protein level and the degree of O-glycosylation were greater in cancer than in normal cells. FXYD5-induced impairment of adhesion was abolished by both genetic and pharmacological inhibition of FXYD5 O-glycosylation. Therefore, the extracellular O-glycosylated domain of FXYD5 impairs adhesion by interfering with intercellular β1-β1 interactions, suggesting that the ratio between FXYD5 and α1-β1 heterodimer determines whether the Na,K-ATPase acts as a positive or negative regulator of intercellular adhesion.
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Affiliation(s)
- Elmira Tokhtaeva
- Department of Physiology, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA Veterans Administration Greater Los Angeles Healthcare System, Los Angeles, CA 90095, USA
| | - Haying Sun
- Division of Pulmonary and Critical Care Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Nimrod Deiss-Yehiely
- Division of Pulmonary and Critical Care Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Yi Wen
- Department of Physiology, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA Veterans Administration Greater Los Angeles Healthcare System, Los Angeles, CA 90095, USA
| | - Pritin N Soni
- Division of Pulmonary and Critical Care Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Nieves M Gabrielli
- Division of Pulmonary and Critical Care Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA Instituto de Biología y Medicina Experimental (CONICET-FIBYME), Buenos Aires C1418ADN, Argentina
| | - Elizabeth A Marcus
- Veterans Administration Greater Los Angeles Healthcare System, Los Angeles, CA 90095, USA Department of Pediatrics, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA
| | - Karen M Ridge
- Division of Pulmonary and Critical Care Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - George Sachs
- Department of Physiology, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA Veterans Administration Greater Los Angeles Healthcare System, Los Angeles, CA 90095, USA
| | - Mónica Vazquez-Levin
- Instituto de Biología y Medicina Experimental (CONICET-FIBYME), Buenos Aires C1418ADN, Argentina
| | - Jacob I Sznajder
- Division of Pulmonary and Critical Care Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Olga Vagin
- Department of Physiology, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA Veterans Administration Greater Los Angeles Healthcare System, Los Angeles, CA 90095, USA
| | - Laura A Dada
- Division of Pulmonary and Critical Care Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
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13
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β1-Na(+),K(+)-ATPase gene therapy upregulates tight junctions to rescue lipopolysaccharide-induced acute lung injury. Gene Ther 2016; 23:489-99. [PMID: 26910760 DOI: 10.1038/gt.2016.19] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Revised: 01/08/2016] [Accepted: 01/19/2016] [Indexed: 01/05/2023]
Abstract
Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are associated with diverse disorders and characterized by disruption of the alveolar-capillary barrier, leakage of edema fluid into the lung, and substantial inflammation leading to acute respiratory failure. Gene therapy is a potentially powerful approach to treat ALI/ARDS through repair of alveolar epithelial function. Herein, we show that delivery of a plasmid expressing β1-subunit of the Na(+),K(+)-ATPase (β1-Na(+),K(+)-ATPase) alone or in combination with epithelial sodium channel (ENaC) α1-subunit using electroporation not only protected from subsequent lipopolysaccharide (LPS)-mediated lung injury, but also treated injured lungs. However, transfer of α1-subunit of ENaC (α1-ENaC) alone only provided protection benefit rather than treatment benefit although alveolar fluid clearance had been remarkably enhanced. Gene transfer of β1-Na(+),K(+)-ATPase, but not α1-ENaC, not only enhanced expression of tight junction protein zona occludins-1 (ZO-1) and occludin both in cultured cells and in mouse lungs, but also reduced pre-existing increase of lung permeability in vivo. These results demonstrate that gene transfer of β1-Na(+),K(+)-ATPase upregulates tight junction formation and therefore treats lungs with existing injury, whereas delivery of α1-ENaC only maintains pre-existing tight junction but not for generation. This indicates that the restoration of epithelial/endothelial barrier function may provide better treatment of ALI/ARDS.
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14
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Molecular and functional characterization of seven Na+/K+-ATPase β subunit paralogs in Senegalese sole (Solea senegalensis Kaup, 1858). Comp Biochem Physiol B Biochem Mol Biol 2015; 182:14-26. [DOI: 10.1016/j.cbpb.2014.11.011] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2014] [Revised: 11/24/2014] [Accepted: 11/29/2014] [Indexed: 11/22/2022]
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15
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Rossier BC, Baker ME, Studer RA. Epithelial sodium transport and its control by aldosterone: the story of our internal environment revisited. Physiol Rev 2015; 95:297-340. [PMID: 25540145 DOI: 10.1152/physrev.00011.2014] [Citation(s) in RCA: 149] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Transcription and translation require a high concentration of potassium across the entire tree of life. The conservation of a high intracellular potassium was an absolute requirement for the evolution of life on Earth. This was achieved by the interplay of P- and V-ATPases that can set up electrochemical gradients across the cell membrane, an energetically costly process requiring the synthesis of ATP by F-ATPases. In animals, the control of an extracellular compartment was achieved by the emergence of multicellular organisms able to produce tight epithelial barriers creating a stable extracellular milieu. Finally, the adaptation to a terrestrian environment was achieved by the evolution of distinct regulatory pathways allowing salt and water conservation. In this review we emphasize the critical and dual role of Na(+)-K(+)-ATPase in the control of the ionic composition of the extracellular fluid and the renin-angiotensin-aldosterone system (RAAS) in salt and water conservation in vertebrates. The action of aldosterone on transepithelial sodium transport by activation of the epithelial sodium channel (ENaC) at the apical membrane and that of Na(+)-K(+)-ATPase at the basolateral membrane may have evolved in lungfish before the emergence of tetrapods. Finally, we discuss the implication of RAAS in the origin of the present pandemia of hypertension and its associated cardiovascular diseases.
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Affiliation(s)
- Bernard C Rossier
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland; Division of Nephrology-Hypertension, University of California San Diego, La Jolla, California; and Institute of Structural and Molecular Biology, Division of Biosciences, University College London, London, United Kingdom
| | - Michael E Baker
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland; Division of Nephrology-Hypertension, University of California San Diego, La Jolla, California; and Institute of Structural and Molecular Biology, Division of Biosciences, University College London, London, United Kingdom
| | - Romain A Studer
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland; Division of Nephrology-Hypertension, University of California San Diego, La Jolla, California; and Institute of Structural and Molecular Biology, Division of Biosciences, University College London, London, United Kingdom
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16
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Tokhtaeva E, Capri J, Marcus EA, Whitelegge JP, Khuzakhmetova V, Bukharaeva E, Deiss-Yehiely N, Dada LA, Sachs G, Fernandez-Salas E, Vagin O. Septin dynamics are essential for exocytosis. J Biol Chem 2015; 290:5280-97. [PMID: 25575596 DOI: 10.1074/jbc.m114.616201] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Septins are a family of 14 cytoskeletal proteins that dynamically form hetero-oligomers and organize membrane microdomains for protein complexes. The previously reported interactions with SNARE proteins suggested the involvement of septins in exocytosis. However, the contradictory results of up- or down-regulation of septin-5 in various cells and mouse models or septin-4 in mice suggested either an inhibitory or a stimulatory role for these septins in exocytosis. The involvement of the ubiquitously expressed septin-2 or general septin polymerization in exocytosis has not been explored to date. Here, by nano-LC with tandem MS and immunoblot analyses of the septin-2 interactome in mouse brain, we identified not only SNARE proteins but also Munc-18-1 (stabilizes assembled SNARE complexes), N-ethylmaleimide-sensitive factor (NSF) (disassembles SNARE complexes after each membrane fusion event), and the chaperones Hsc70 and synucleins (maintain functional conformation of SNARE proteins after complex disassembly). Importantly, α-soluble NSF attachment protein (SNAP), the adaptor protein that mediates NSF binding to the SNARE complex, did not interact with septin-2, indicating that septins undergo reorganization during each exocytosis cycle. Partial depletion of septin-2 by siRNA or impairment of septin dynamics by forchlorfenuron inhibited constitutive and stimulated exocytosis of secreted and transmembrane proteins in various cell types. Forchlorfenuron impaired the interaction between SNAP-25 and its chaperone Hsc70, decreasing SNAP-25 levels in cultured neuroendocrine cells, and inhibited both spontaneous and stimulated acetylcholine secretion in mouse motor neurons. The results demonstrate a stimulatory role of septin-2 and the dynamic reorganization of septin oligomers in exocytosis.
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Affiliation(s)
- Elmira Tokhtaeva
- From the Departments of Physiology and Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California 90073
| | - Joe Capri
- The Neuropsychiatric Institute-Semel Institute, Pasarow Mass Spectrometry Laboratory, UCLA, Los Angeles, California 90024
| | - Elizabeth A Marcus
- Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California 90073, Pediatrics, David Geffen School of Medicine at UCLA, Los Angeles, California 90095
| | - Julian P Whitelegge
- The Neuropsychiatric Institute-Semel Institute, Pasarow Mass Spectrometry Laboratory, UCLA, Los Angeles, California 90024
| | - Venera Khuzakhmetova
- Kazan Institute of Biochemistry and Biophysics, Kazan Scientific Center of the Russian Academy of Sciences, Kazan 420111, Russia, Kazan Federal University, Kazan 420008, Russia
| | - Ellya Bukharaeva
- Kazan Institute of Biochemistry and Biophysics, Kazan Scientific Center of the Russian Academy of Sciences, Kazan 420111, Russia, Kazan Federal University, Kazan 420008, Russia
| | - Nimrod Deiss-Yehiely
- Division of Pulmonary and Critical Care Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, and
| | - Laura A Dada
- Division of Pulmonary and Critical Care Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, and
| | - George Sachs
- From the Departments of Physiology and Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California 90073
| | - Ester Fernandez-Salas
- Department of Pathology, School of Medicine, University of Michigan, Ann Arbor, Michigan 48109
| | - Olga Vagin
- From the Departments of Physiology and Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California 90073,
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17
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Vagin O, Tokhtaeva E, Garay PE, Souda P, Bassilian S, Whitelegge JP, Lewis R, Sachs G, Wheeler L, Aoki R, Fernandez-Salas E. Recruitment of septin cytoskeletal proteins by botulinum toxin A protease determines its remarkable stability. J Cell Sci 2014; 127:3294-308. [PMID: 24928902 DOI: 10.1242/jcs.146324] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Proteolytic cleavage of synaptosomal-associated protein 25 by the light chain of botulinum neurotoxin type A (LCA) results in a blockade of neurotransmitter release that persists for several months in motor neurons. The L428A/L429A mutation in LCA is known to significantly shorten both the proteolytic and neuroparalytic effects of the neurotoxin in mice. To elucidate the cellular mechanism for LCA longevity, we studied the effects of L428A/L429A mutation on the interactome, localization and stability of LCA expressed in cultured neuronal cells. Mass spectrometry analysis of the LCA interactome showed that the mutation prevented the interaction of LCA with septins. The wild-type LCA was concentrated in plasma-membrane-associated clusters, colocalizing with septins-2 and septin-7, which accumulated in these clusters only in the presence of LCA. The L428A/L429A mutation decreased co-clustering of LCA and septins and accelerated proteasomal and non-proteasomal degradation of LCA. Similarly, the impairment of septin oligomerization by forchlorfenuron or silencing of septin-2 prevented LCA interaction and clustering with septins and increased LCA degradation. Therefore, the dileucine-mediated LCA-septin co-clustering is crucial for the long-lasting stabilization of LCA-related proteolytic and presumably neuroparalytic activity.
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Affiliation(s)
- Olga Vagin
- Department of Physiology, School of Medicine, UCLA and Veterans Administration Greater Los Angeles Health Care System, Los Angeles, CA 91343, USA
| | - Elmira Tokhtaeva
- Department of Physiology, School of Medicine, UCLA and Veterans Administration Greater Los Angeles Health Care System, Los Angeles, CA 91343, USA
| | - Patton E Garay
- Department of Biological Sciences, Allergan Inc., Irvine, CA 92612, USA
| | - Puneet Souda
- The NPI-Semel Institute, Pasarow Mass Spectrometry Laboratory, UCLA, Los Angeles, CA 90095, USA
| | - Sara Bassilian
- Department of Physiology, School of Medicine, UCLA and Veterans Administration Greater Los Angeles Health Care System, Los Angeles, CA 91343, USA
| | - Julian P Whitelegge
- The NPI-Semel Institute, Pasarow Mass Spectrometry Laboratory, UCLA, Los Angeles, CA 90095, USA
| | - Ramilla Lewis
- Department of Biological Sciences, Allergan Inc., Irvine, CA 92612, USA
| | - George Sachs
- Department of Physiology, School of Medicine, UCLA and Veterans Administration Greater Los Angeles Health Care System, Los Angeles, CA 91343, USA
| | - Larry Wheeler
- Department of Biological Sciences, Allergan Inc., Irvine, CA 92612, USA
| | - Roger Aoki
- Department of Biological Sciences, Allergan Inc., Irvine, CA 92612, USA
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18
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Hu LYR, Kontrogianni-Konstantopoulos A. The kinase domains of obscurin interact with intercellular adhesion proteins. FASEB J 2013; 27:2001-12. [PMID: 23392350 DOI: 10.1096/fj.12-221317] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Obscurins comprise a family of giant (~870- to 600-kDa) and small (~250- to 55-kDa) proteins that play important roles in myofibrillogenesis, cytoskeletal organization, and cell adhesion and are implicated in hypertrophic cardiomyopathy and tumorigenesis. Giant obscurins are composed of tandem structural and signaling motifs, including 2 serine/threonine kinase domains, SK1 and SK2, present at the COOH terminus of giant obscurin-B. Using biochemical and cellular approaches, we show for the first time that both SK1 and SK2 possess enzymatic activities and undergo autophosphorylation. SK2 can phosphorylate the cytoplasmic domain of N-cadherin, a major component of adherens junctions, and SK1 can interact with the extracellular domain of the β1-subunit of the Na(+)/K(+)-ATPase, which also resides in adherens junctions. Immunostaining of nonpermeabilized myofibers and cardiocytes revealed that some obscurin kinase isoforms localize extracellularly. Quantification of the exofacial expression of obscurin kinase proteins indicated that they occupy ~16 and ~5% of the sarcolemmal surface in myofibers and cardiocytes, respectively. Treatment of heart lysates with peptide-N-glycosidase F revealed that while giant obscurin-B localizes intracellularly, possessing dual kinase activity, a small obscurin kinase isoform that contains SK1 localizes extracellularly, where it undergoes N-glycosylation. Collectively, our studies demonstrate that the obscurin kinase domains are enzymatically active and may be involved in the regulation of cell adhesion.
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Affiliation(s)
- Li-Yen R Hu
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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19
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Reinhard L, Tidow H, Clausen MJ, Nissen P. Na(+),K (+)-ATPase as a docking station: protein-protein complexes of the Na(+),K (+)-ATPase. Cell Mol Life Sci 2013; 70:205-22. [PMID: 22695678 PMCID: PMC11113973 DOI: 10.1007/s00018-012-1039-9] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2012] [Revised: 05/13/2012] [Accepted: 05/23/2012] [Indexed: 12/13/2022]
Abstract
The Na(+),K(+)-ATPase, or sodium pump, is well known for its role in ion transport across the plasma membrane of animal cells. It carries out the transport of Na(+) ions out of the cell and of K(+) ions into the cell and thus maintains electrolyte and fluid balance. In addition to the fundamental ion-pumping function of the Na(+),K(+)-ATPase, recent work has suggested additional roles for Na(+),K(+)-ATPase in signal transduction and biomembrane structure. Several signaling pathways have been found to involve Na(+),K(+)-ATPase, which serves as a docking station for a fast-growing number of protein interaction partners. In this review, we focus on Na(+),K(+)-ATPase as a signal transducer, but also briefly discuss other Na(+),K(+)-ATPase protein-protein interactions, providing a comprehensive overview of the diverse signaling functions ascribed to this well-known enzyme.
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Affiliation(s)
- Linda Reinhard
- Danish National Research Foundation, Centre for Membrane Pumps in Cells and Disease-PUMPKIN, Department of Molecular Biology and Genetics, 8000 Aarhus C, Denmark
| | - Henning Tidow
- Danish National Research Foundation, Centre for Membrane Pumps in Cells and Disease-PUMPKIN, Department of Molecular Biology and Genetics, 8000 Aarhus C, Denmark
| | - Michael J. Clausen
- Danish National Research Foundation, Centre for Membrane Pumps in Cells and Disease-PUMPKIN, Department of Molecular Biology and Genetics, 8000 Aarhus C, Denmark
| | - Poul Nissen
- Danish National Research Foundation, Centre for Membrane Pumps in Cells and Disease-PUMPKIN, Department of Molecular Biology and Genetics, 8000 Aarhus C, Denmark
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20
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Vagin O, Dada LA, Tokhtaeva E, Sachs G. The Na-K-ATPase α₁β₁ heterodimer as a cell adhesion molecule in epithelia. Am J Physiol Cell Physiol 2012; 302:C1271-81. [PMID: 22277755 DOI: 10.1152/ajpcell.00456.2011] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The ion gradients generated by the Na-K-ATPase play a critical role in epithelia by driving transepithelial transport of various solutes. The efficiency of this Na-K-ATPase-driven vectorial transport depends on the integrity of epithelial junctions that maintain polar distribution of membrane transporters, including the basolateral sodium pump, and restrict paracellular diffusion of solutes. The review summarizes the data showing that, in addition to pumping ions, the Na-K-ATPase located at the sites of cell-cell junction acts as a cell adhesion molecule by interacting with the Na-K-ATPase of the adjacent cell in the intercellular space accompanied by anchoring to the cytoskeleton in the cytoplasm. The review also discusses the experimental evidence on the importance of a specific amino acid region in the extracellular domain of the Na-K-ATPase β(1) subunit for the Na-K-ATPase trans-dimerization and intercellular adhesion. Furthermore, a possible role of N-glycans linked to the Na-K-ATPase β(1) subunit in regulation of epithelial junctions by modulating β(1)-β(1) interactions is discussed.
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Affiliation(s)
- Olga Vagin
- Department of Physiology, School of Medicine, University of California Los Angeles and Veterans Administration Greater Los Angeles Health Care System, Los Angeles, California, USA.
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