IDENTIFICATION AND FUNCTIONAL-CHARACTERIZATION OF A K-SUBUNIT WITH REGULATORY PROPERTIES SPECIFIC TO BRAIN( CHANNEL ALPHA)

The physiological diversity oi K+ channels mainly depends on the expre ssion of several genes encoding different alpha-subunits. We have clon ed a new K+ channel alpha-subunit (Kv2.3r) that is unable to form func tional channels on its own but that has a major regulatory function. K v2.3r can coassemble selectively with other alpha-subunits to form fun ctional heteromultimeric K+ channels with kinetic properties that diff er 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 alpha-subunit represents a novel mechanism without precedents in voltage-gated channels, which might contribute to further increase the functional diversity of K+ ch annels necessary to specify the intrinsic electrical properties of ind ividual neurons.