The mouse TWIK-1 K+ channel forms a disulfide-linked dimer, produces weakly inward rectifying K+ currents, and is highly expressed in specific brain regions such as cerebellar granule cells.
The study characterizes the structure, function, and distribution of the mouse TWIK-1 K+ channel, revealing its properties as a weakly inward rectifying channel that dimerizes via a disulfide bridge and is predominantly expressed in the brain.
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 quinine, decreased by protein kinase C and increased by internal acidification. The apparent molecular weight of mTWIK-1 in brain is 81 kDa. A 40 kDa form is revealed after treatment with a reducing agent, strongly suggesting that native mTWIK-1 subunits dimerize via a disulfide bridge. TWIK-1 mRNA is expressed abundantly in brain and at lower levels in lung, kidney, and skeletal muscle. In situ hybridization shows that mTWIK-1 expression is restricted to a few brain regions, with the highest levels in cerebellar granule cells, brainstem, hippocampus and cerebral cortex.
Lesage et al. (1997) studied this question. The mouse TWIK-1 K+ channel forms a disulfide-linked dimer, produces weakly inward rectifying K+ currents, and is highly expressed in specific brain regions such as cerebellar granule cells.