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.