Hiromichi Yokoi

Molecular cloning and characterization of Kv6.3, a novel modulatory subunit for voltage‐gated K+ channel Kv2.11

We report identification and characterization of Kv6.3, a novel member of the voltage‐gated K+ channel. Reverse transcriptase‐polymerase chain reaction analysis indicated that Kv6.3 was highly expressed in the brain. Electrophysiological studies indicated that homomultimeric Kv6.3 did not yield a functional voltage‐gated ion channel. When Kv6.3 and Kv2.1 were co‐expressed, the heteromultimeric channels displayed the decreased rate of deactivation compared to the homomultimeric Kv2.1 channels. Immunoprecipitation studies indicated that Kv6.3 bound with Kv2.1 in co‐transfected cells. These results indicate that Kv6.3 is a novel member of the voltage‐gated K+ channel which functions as a modulatory subunit.

New Ether-à-go-go K+ Channel Family Members Localized in Human Telencephalon

A cDNA encoding a novel voltage-gated K+ channel protein was isolated from human brain. This protein, termed BEC1, is 46% identical to rat elk in theether-à-go-go K+ channel family. TheBEC1 gene maps to the 12q13 region of the human genome. Northern blot analysis indicates that BEC1 is exclusively expressed in human brain, where the expression is concentrated in the telencephalic areas such as the cerebral cortex, amygdala, hippocampus, and striatum. By in situ hybridization, BEC1 is detected in the CA1–CA3 pyramidal cell layers and the dentate gyrus granule cell layers of the hippocampus. Specific signals are also found in neocortical neurons. Transfection of mammalian L929 and Chinese hamster ovary cells with BEC1 cDNA induces a voltage-gated outward current with a fast inactivation component. This current is insensitive to tetraethylammonium and quinidine. Additionally, a second related gene BEC2 was isolated from human brain. BEC2 is also brain-specific, located in the neocortex and the striatum, and functional as a channel gene. Phylogenetic analysis indicates that BEC1 andBEC2 constitute a subfamily, together with elk, in the ether-à-go-go family. The two genes may be involved in cellular excitability of restricted neurons in the human central nervous system.