Kv7.2-7.3- “Cross-site study of neuronal KV7.2/7.3 heteromers on the Patchliner”

The KV7 channels are a family of voltage-gated potassium ion channels with five members (KV7.1 – 7.5) encoded by the KCNQ1-5 genes1. The channels exist as tetramers, with each subunit containing six transmembrane domains with cytoplasmic N- and C-termini. The long intracellular terminus is essential for tetramerization as well as interaction with critical regulators such as PIP2, calmodulin, protein kinase C and ankyrin G2. KV7-mediated currents are voltage activated, slowly activating and non-inactivating and are involved in repolarization of the cell membrane potential, thereby controlling cell excitability. KV7.1 channels are primarily expressed in cardiac cells whereas KV7.2, KV7.3 and KV7.5 are widely distributed in neuronal and primary sensory cells2. KV7.2/7.3 heteromeric channels primarily underlie the neuronal M-current (IKM)which plays a crucial role in repolarizing neuronal membrane potential after a depolarizing input which limits repetitive firing and is, therefore, a key mechanism in spike frequency adaptation.