In mammals, a large family of genes encodes α-subunits: KV1 (homologous to Drosophila Shaker), KV2 (Shab), KV3 (Shaw), KV4 (Shal), KV5, KV6, and KV9. The sparsely populated KV channel subfamilies KV5 and KV6 each contain one member, KV5.1 and KV6.1. KV6 channels are electrically silent and no functional role has been suggested for these channels. A recent study found that KV6.1 forms functional channels specifically with KV2.1. It was also found that KV2.1 and KV6.1 mRNAs colocalize to the piriform cortex, hippocampus, dendate gyrus and olfactory tubercle in the brain4 and to SA node, atria and ventricle in the heart5. This suggests that KV6.1 may be physiologically important in generating an increased number of KV channel phenotypes even though it does not itself form functional homomultimeric channels. nAnother study found that KV6.1 regulates the kinetics of KV2.2 channels. KV2.1/6.1 coexpression results in channels with markedly slower inactivation during strong depolarization but faster inactivation at intermediate potentials