title: Sodium-calcium exchanger 1 regulates epithelial cell migration via calcium-dependent extracellular signal-regulated kinase signaling.
abstract: Na(+)/Ca(2+) exchanger-1 (NCX1) is a major calcium extrusion mechanism in renal epithelial cells enabling the efflux of one Ca(2+) ion and the influx of three Na(+) ions. The gradient for this exchange activity is provided by Na,K-ATPase, a hetero-oligomer consisting of a catalytic α-subunit and a regulatory β-subunit (Na,K-β) that also functions as a motility and tumor suppressor. We showed earlier that mice with heart-specific ablation (KO) of Na,K-β had a specific reduction in NCX1 protein and were ouabain-insensitive. Here, we demonstrate that Na,K-β associates with NCX1 and regulates its localization to the cell surface. Madin-Darby canine kidney cells with Na,K-β knockdown have reduced NCX1 protein and function accompanied by 2.1-fold increase in free intracellular calcium and a corresponding increase in the rate of cell migration. Increased intracellular calcium up-regulated ERK1/2 via calmodulin-dependent activation of PI3K. Both myosin light chain kinase and Rho-associated kinase acted as mediators of ERK1/2-dependent migration. Restoring NCX1 expression in β-KD cells reduced migration rate and ERK1/2 activation, suggesting that NCX1 functions downstream of Na,K-β in regulating cell migration. In parallel, inhibition of NCX1 by KB-R7943 in Madin-Darby canine kidney cells, LLC-PK1, and human primary renal epithelial cells (HREpiC) increased ERK1/2 activation and cell migration. This increased migration was associated with high myosin light chain phosphorylation by PI3K/ERK-dependent mechanism in HREpiC cells. These data confirm the role of NCX1 activity in regulating renal epithelial cell migration.
authors.affiliation: From the Nemours Center for Childhood Cancer Research, Alfred I. duPont Hospital for Children, Wilmington, Delaware 19803 and Department of Biological Sciences, University of Delaware, Newark, Delaware 19716.
authors.forename: Sona Lakshme
authors.initials: SL
authors.lastname: Balasubramaniam
authors.affiliation: From the Nemours Center for Childhood Cancer Research, Alfred I. duPont Hospital for Children, Wilmington, Delaware 19803 and.
authors.forename: Anilkumar
authors.initials: A
authors.lastname: Gopalakrishnapillai
authors.affiliation: Department of Biological Sciences, University of Delaware, Newark, Delaware 19716.
authors.forename: Vimal
authors.initials: V
authors.lastname: Gangadharan
authors.affiliation: Department of Biological Sciences, University of Delaware, Newark, Delaware 19716.
authors.forename: Randall L
authors.initials: RL
authors.lastname: Duncan
authors.affiliation: From the Nemours Center for Childhood Cancer Research, Alfred I. duPont Hospital for Children, Wilmington, Delaware 19803 and Department of Biological Sciences, University of Delaware, Newark, Delaware 19716 barwe@medsci.udel.edu.
authors.forename: Sonali P
authors.initials: SP
authors.lastname: Barwe
mesh_terms: D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002465:Cell Movement / Q000187:drug effects / Q000502:physiology*; D004285:Dogs; D004789:Enzyme Activation / Q000187:drug effects / Q000502:physiology; D006801:Humans; D007668:Kidney / Q000378:metabolism; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000502:physiology*; D061985:Madin Darby Canine Kidney Cells; D051379:Mice; D019950:Mitogen-Activated Protein Kinase 1 / Q000235:genetics / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000235:genetics / Q000378:metabolism*; D009219:Myosin-Light-Chain Kinase / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects / Q000502:physiology; D019831:Sodium-Calcium Exchanger / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D000254:Sodium-Potassium-Exchanging ATPase / Q000235:genetics / Q000378:metabolism; D013890:Thiourea / Q000031:analogs & derivatives / Q000494:pharmacology; D054460:rho-Associated Kinases / Q000235:genetics / Q000378:metabolism
chemical_list: C101670:2-(2-(4-(4-nitrobenzyloxy)phenyl)ethyl)isothiourea methanesulfonate; D000889:Anti-Arrhythmia Agents; D019831:Sodium-Calcium Exchanger; C110374:sodium-calcium exchanger 1; D054460:rho-Associated Kinases; D009219:Myosin-Light-Chain Kinase; C535150:MAPK1 protein, human; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D000254:Sodium-Potassium-Exchanging ATPase; D013890:Thiourea; D002118:Calcium
keywords: Calcium; Cell Migration; Extracellular Signal-regulated Kinase (ERK); NCX1; Na+/K+-ATPase; Sodium-Calcium Exchange