Plasma membrane voltage-dependent anion channel mediates antiestrogen-activated maxi Cl- currents in C1300 neuroblastoma cells.
The cell membrane large conductance voltage-dependent chloride channel (Maxi Cl- channel) has been recorded in different cell types following excision of membrane patches or stimulation by antiestrogens under whole-cell recording conditions. However, both its molecular nature and relevance to cell physiology await elucidation. Its electrophysiological properties resemble those of the voltage-dependent anion channel (VDAC) of the outer mitochondrial membrane. This observation has led to the controversial hypothesis that VDAC could be the molecular correlate of the plasma membrane Maxi Cl- channel. We have investigated the cellular localization of VDAC and its relationship with the antiestrogen-activated Maxi Cl- current in C1300 neuroblastoma cells. The presence of a plasma membrane VDAC was demonstrated by immunoblotting of membrane fractions with monoclonal antibodies against the VDAC and by reverse transcription-PCR using primers that hybridize to a VDAC sequence coding for an N-terminal leader peptide required for its plasma membrane sorting. Besides, VDAC colocalized with markers of plasma membrane lipid rafts (cholera toxin beta subunit) but not caveolin-1. Transfection of C1300 cells with an antisense oligonucleotide directed against the specific membrane leader sequence of VDAC markedly reduced both VDAC immunostaining and antiestrogen-activated Maxi Cl- currents, suggesting that VDAC forms the plasma membrane Maxi Cl- channel or a part thereof.
Bahamonde
Maria I
MI
Unitat de Senyalització Cel.lular, Departament de Ciències Experimentals i de la Salut, Universitat Pompeu Fabra, C/ Dr. Aiguader 80, Barcelona 08003, Spain.
Fernández-Fernández
José M
JM
Guix
Francesc X
FX
Vázquez
Esther
E
Valverde
Miguel A
MA
D000818:Animals; D000838:Anions / Q000737:chemistry; D015153:Blotting, Western; D002462:Cell Membrane / Q000378:metabolism*; D018118:Chloride Channels / Q000737:chemistry; D002713:Chlorine / Q000378:metabolism; D017931:DNA Primers / Q000494:pharmacology; D004594:Electrophysiology; D020847:Estrogen Receptor Modulators / Q000737:chemistry / Q000494:pharmacology; D015151:Immunoblotting; D007425:Intracellular Membranes / Q000378:metabolism; D021962:Membrane Microdomains / Q000737:chemistry; D051379:Mice; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D016376:Oligonucleotides, Antisense / Q000737:chemistry / Q000494:pharmacology; D018272:Porins / Q000737:chemistry* / Q000378:metabolism*; D020033:Protein Isoforms; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014407:Tumor Cells, Cultured; D050994:Voltage-Dependent Anion Channels
D000838:Anions; D018118:Chloride Channels; D017931:DNA Primers; D020847:Estrogen Receptor Modulators; D016376:Oligonucleotides, Antisense; D018272:Porins; D020033:Protein Isoforms; D050994:Voltage-Dependent Anion Channels; D002713:Chlorine