TRESK-like potassium channels in leukemic T cells.
In this study, we present patch-clamp characterization of the background potassium current in human lymphoma (Jurkat cells), generated by voltage-independent 16 pS channels with a high ( approximately 100-fold) K+/Na+ selectivity. Depending on the background K+ channels density, from few per cell up to approximately 1 open channel per microm2, resting membrane potential was in the range of -40 to -83 mV, approaching E (K) = -88 mV. The background K+ channels were insensitive to margotoxin (3 nM), apamine (3 nM), and clotrimazole (1 microM), high-affinity blockers of the lymphocyte Kv1.3, SKCa2, and IKCa1 channels. The current depended weakly on external pH. Arachidonic acid (20 microM) and Hg2+ (0.3-10 microM) suppressed background K+ current in Jurkat cells by 75-90%. Background K+ current was weakly sensitive to TEA+ (IC50 = 14 mM), and was efficiently suppressed by externally applied bupivacaine (IC50 = 5 microM), quinine (IC50 = 16 microM), and Ba2+ (2 mM). Our data, in particular strong inhibition by mercuric ions, suggest that background K+ currents expressed in Jurkat cells are mediated by TWIK-related spinal cord K+ (TRESK) channels belonging to the double-pore domain K+ channel family. The presence of human TRESK in the membrane protein fraction was confirmed by Western blot analysis.
Pottosin
Igor I
II
Centro Universitario de Investigaciones Biomédicas, Universidad de Colima, Av. 25 de Julio 965, Villa San Sebastian, 28045, Colima, Mexico.
Bonales-Alatorre
Edgar
E
Valencia-Cruz
Georgina
G
Mendoza-Magaña
Maria Luisa
ML
Dobrovinskaya
Oxana R
OR
D015153:Blotting, Western; D004594:Electrophysiology; D006801:Humans; D019169:Jurkat Cells; D051664:Kv1.3 Potassium Channel / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism; D008565:Membrane Proteins / Q000302:isolation & purification / Q000378:metabolism; D018408:Patch-Clamp Techniques; D026902:Potassium Channel Blockers / Q000494:pharmacology; D015221:Potassium Channels / Q000737:chemistry / Q000187:drug effects / Q000502:physiology*; D024681:Potassium Channels, Calcium-Activated / Q000737:chemistry / Q000187:drug effects / Q000502:physiology; D013116:Spinal Cord / Q000378:metabolism
C476574:KCNK18 protein, human; D051664:Kv1.3 Potassium Channel; D008565:Membrane Proteins; D026902:Potassium Channel Blockers; D015221:Potassium Channels; D024681:Potassium Channels, Calcium-Activated