The nef protein of the human immunodeficiency virus type 1 (HIV-1) inhibits a large-conductance potassium channel in human glial cells.
The Nef protein of human immunodeficiency virus type 1 (HIV-1) is abundantly expressed in HIV-1-infected astrocytes and shares amino acid sequence homology to alpha-scorpion toxins which bind to potassium channels. Here we report effects of recombinant Nef and alpha-scorpion toxins on membrane potassium transport in human U251 astroglioma cells. 86Rb+ was utilized as a tracer for potassium movements and potassium channel activity was studied by single-channel patch-clamp techniques. Results showed inactivation of a large-conductance potassium channel when Nef was added to the inner leaflet of the cell membrane of inside-out patches of U251 cells. Extracellular addition of Nef or alpha-scorpion toxins to intact glial cells did not alter potassium transport.
Department of Medicine, Albany Medical College, NY 12208, USA. jkort@ccgateway.amc.edu
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D000595:Amino Acid Sequence; D001254:Astrocytoma; D001464:Barium / Q000494:pharmacology; D002034:Bumetanide / Q000494:pharmacology; D015693:Gene Products, nef / Q000737:chemistry / Q000494:pharmacology*; D015497:HIV-1; D006801:Humans; D051036:Large-Conductance Calcium-Activated Potassium Channels; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D009457:Neuroglia / Q000187:drug effects / Q000502:physiology*; D010042:Ouabain / Q000494:pharmacology; D018408:Patch-Clamp Techniques; D026902:Potassium Channel Blockers; D015221:Potassium Channels / Q000502:physiology; D024681:Potassium Channels, Calcium-Activated; D011994:Recombinant Proteins / Q000494:pharmacology; D012604:Scorpion Venoms / Q000737:chemistry / Q000494:pharmacology; D016415:Sequence Alignment; D014407:Tumor Cells, Cultured; D054311:nef Gene Products, Human Immunodeficiency Virus
D015693:Gene Products, nef; D051036:Large-Conductance Calcium-Activated Potassium Channels; D026902:Potassium Channel Blockers; D015221:Potassium Channels; D024681:Potassium Channels, Calcium-Activated; D011994:Recombinant Proteins; D012604:Scorpion Venoms; D054311:nef Gene Products, Human Immunodeficiency Virus; D002034:Bumetanide; D001464:Barium; D010042:Ouabain