title: Tungstate-targeting of BKαβ1 channels tunes ERK phosphorylation and cell proliferation in human vascular smooth muscle.
abstract: Despite the substantial knowledge on the antidiabetic, antiobesity and antihypertensive actions of tungstate, information on its primary target/s is scarce. Tungstate activates both the ERK1/2 pathway and the vascular voltage- and Ca2+-dependent large-conductance BKαβ1 potassium channel, which modulates vascular smooth muscle cell (VSMC) proliferation and function, respectively. Here, we have assessed the possible involvement of BKαβ1 channels in the tungstate-induced ERK phosphorylation and its relevance for VSMC proliferation. Western blot analysis in HEK cell lines showed that expression of vascular BKαβ1 channels potentiates the tungstate-induced ERK1/2 phosphorylation in a Gi/o protein-dependent manner. Tungstate activated BKαβ1 channels upstream of G proteins as channel activation was not altered by the inhibition of G proteins with GDPβS or pertussis toxin. Moreover, analysis of Gi/o protein activation measuring the FRET among heterologously expressed Gi protein subunits suggested that tungstate-targeting of BKαβ1 channels promotes G protein activation. Single channel recordings on VSMCs from wild-type and β1-knockout mice indicated that the presence of the regulatory β1 subunit was essential for the tungstate-mediated activation of BK channels in VSMCs. Moreover, the specific BK channel blocker iberiotoxin lowered tungstate-induced ERK phosphorylation by 55% and partially reverted (by 51%) the tungstate-produced reduction of platelet-derived growth factor (PDGF)-induced proliferation in human VSMCs. Our observations indicate that tungstate-targeting of BKαβ1 channels promotes activation of PTX-sensitive Gi proteins to enhance the tungstate-induced phosphorylation of ERK, and inhibits PDGF-stimulated cell proliferation in human vascular smooth muscle.
authors: Laboratori de Fisiologia Molecular i Canalopaties, Departament de Ciències Experimentals i de la Salut, Universitat Pompeu Fabra, Barcelona, Spain.
authors: Ana Isabel
authors: AI
authors: Fernández-Mariño
authors: Departamento de Bioquímica y Biología Molecular y Fisiología and Instituto de Biología y Genética Molecular (IBGM), Universidad de Valladolid and Consejo Superior de Investigaciones Científicas (CSIC), Valladolid, Spain.
authors: Pilar
authors: P
authors: Cidad
authors: Institute for Research in Biomedicine (IRB Barcelona) and Department of Biochemistry and Molecular Biology, University of Barcelona, and Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas (CIBERDEM), Barcelona, Spain.
authors: Delia
authors: D
authors: Zafra
authors: Institute for Research in Biomedicine (IRB Barcelona) and Department of Biochemistry and Molecular Biology, University of Barcelona, and Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas (CIBERDEM), Barcelona, Spain.
authors: Laura
authors: L
authors: Nocito
authors: Institute for Research in Biomedicine (IRB Barcelona) and Department of Biochemistry and Molecular Biology, University of Barcelona, and Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas (CIBERDEM), Barcelona, Spain.
authors: Jorge
authors: J
authors: Domínguez
authors: Aragon Institute of Health Sciences I+CS/IIS and Fundación Agencia Aragonesa para la Investigación y Desarrollo (ARAID), Zaragoza, Spain.
authors: Aida
authors: A
authors: Oliván-Viguera
authors: Aragon Institute of Health Sciences I+CS/IIS and Fundación Agencia Aragonesa para la Investigación y Desarrollo (ARAID), Zaragoza, Spain.
authors: Ralf
authors: R
authors: Köhler
authors: Departamento de Bioquímica y Biología Molecular y Fisiología and Instituto de Biología y Genética Molecular (IBGM), Universidad de Valladolid and Consejo Superior de Investigaciones Científicas (CSIC), Valladolid, Spain.
authors: José R
authors: JR
authors: López-López
authors: Departamento de Bioquímica y Biología Molecular y Fisiología and Instituto de Biología y Genética Molecular (IBGM), Universidad de Valladolid and Consejo Superior de Investigaciones Científicas (CSIC), Valladolid, Spain.
authors: María Teresa
authors: MT
authors: Pérez-García
authors: Laboratori de Fisiologia Molecular i Canalopaties, Departament de Ciències Experimentals i de la Salut, Universitat Pompeu Fabra, Barcelona, Spain.
authors: Miguel Ángel
authors: MÁ
authors: Valverde
authors: Institute for Research in Biomedicine (IRB Barcelona) and Department of Biochemistry and Molecular Biology, University of Barcelona, and Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas (CIBERDEM), Barcelona, Spain.
authors: Joan J
authors: JJ
authors: Guinovart
authors: Laboratori de Fisiologia Molecular i Canalopaties, Departament de Ciències Experimentals i de la Salut, Universitat Pompeu Fabra, Barcelona, Spain.
authors: José M
authors: JM
authors: Fernández-Fernández
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D020013:Calcium Signaling / Q000187:drug effects* / Q000235:genetics; D048049:Extracellular Signal-Regulated MAP Kinases / Q000235:genetics / Q000378:metabolism*; D019206:GTP-Binding Protein alpha Subunits, Gi-Go / Q000235:genetics / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D051036:Large-Conductance Calcium-Activated Potassium Channels / Q000235:genetics / Q000378:metabolism*; D020935:MAP Kinase Signaling System / Q000187:drug effects* / Q000235:genetics; D051379:Mice; D018345:Mice, Knockout; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology; D017973:Tungsten Compounds / Q000494:pharmacology*
chemical_list: D051036:Large-Conductance Calcium-Activated Potassium Channels; D010982:Platelet-Derived Growth Factor; D017973:Tungsten Compounds; D048049:Extracellular Signal-Regulated MAP Kinases; D019206:GTP-Binding Protein alpha Subunits, Gi-Go; C045951:tungstate; D002118:Calcium