ABSTRACT: Voltage-gated potassium channels (Kv) of the Shaker-related superfamily are assembled from membrane-integrated α subunits and auxiliary β subunits. The β subunits may increase Kv channel surface expression and/or confer A-type behavior to noninactivating Kv channels in heterologous expression systems. The interaction of Kvα and Kvβ subunits depends on the presence or absence of several domains including the amino-terminal N-type inactivating and NIP domains and the Kvα and Kvβ binding domains. Loss of function of Kvβ1.1 subunits leads to a reduction of A-type Kv channel activity in hippocampal and striatal neurons of knock-out mice. This reduction may be correlated with altered cognition and motor control in the knock-out mice.