Identification and Functional Characterization of a K1 Channel a- Subunit with Regulatory Properties Specific to Brain

Abstract

The physiological diversity of K1 channels mainly depends on the expression of several genes encoding different a-subunits. We have cloned a new K1 channel a-subunit (Kv2.3r) that is unable to form functional channels on its own but that has a major regulatory function. Kv2.3r can coassemble selectively with other a-subunits to form functional heteromultimeric K1 channels with kinetic properties that differ from those of the parent channels. Kv2.3r is expressed exclusively in the brain, being concentrated particularly in neocortical neurons. The functional expression of this regulatory a-subunit represents a novel mechanism without precedents in voltage-gated channels, which might contribute to further increase the functional diversity of K1 channels necessary to specify the intrinsic electrical properties of individual neurons.