THE STRUCTURE, FUNCTION AND DISTRIBUTION OF THE MOUSE TWIK-1 K+ CHANNEL

The two P domain K+ channel mTWIK-1 has been cloned from mouse brain, In Xenopus oocytes, mTWIK-1 currents are K+-selective, instantaneous, and weakly inward rectifying, These currents are blocked by Ba2+ and q uinine, decreased by protein kinase C and increased by internal acidif ication, The apparent molecular weight of mTWIK-1 in brain is 81 kDa, A 40 kDa form is revealed after treatment with a reducing agent, stron gly suggesting that native mTWIK-1 subunits dimerize,ia a disulfide br idge, TWIK-1 mRNA is expressed abundantly in brain and at lower levels in lung, kidney, and skeletal muscle, In situ hybridization shows tha t mTWIK-1 expression is restricted to a few brain regions, with the hi ghest levels in cerebellar granule cells, brainstem, hippocampus and c erebral cortex.