KV1.5 is a mammalian voltage-dependent K+ channel, homologous to the DrosophilaShaker K+ channel. KV1.5 was first cloned from rat brain1. Eight Shaker related genes exist in mammals constituting the KV1, subfamily of the large KV channel family of genes2.
A functional KV1 channel is either a membrane spanning homotetramer or heterotetramer, which is composed of members of the same subfamily. In addition several auxiliary subunits and intracellular proteins might interact with the channel and affect its function.
The structure of KV1.5 channel is similar to all KV channels and includes six membrane spanning helixes creating a voltage sensor domain and a pore domain 2.
The channel is expressed in cardiac and smooth muscle tissue (colon, aorta, stomach and pulmonary artery) as well as in neurons and kidney2. A loss of function mutation in the gene encoding the channel was found in atrial fibrilation patients, stressing its role as a cardiac action potential regulator3.
The functional channel is considered a transient (A-type) channel and shows prominent inactivation. Therefore, KV1.5 activity influences the membrane potential and excitability of neurons and muscle.
KV1.5 channels are sensitive to high doses of TEA (330 mM) and low doses of 4-AP (0.27 mM), the “classical” non-selective potassium channel blockers2.
