Alternative splicing in the pore-forming region of shaker potassium channels

We have cloned cDNAs for the shaker potassium channel gene from the spiny lobster Panulirus interruptus. As previously found in Drosophila, there is alternative splicing at the 59 and 39 ends of the coding region. However, in Panulirus shaker, alternative splicing also occurs within the pore-forming region of the protein. Three different splice variants were found within the P region, two of which bestow unique electrophysiological characteristics to channel function. Pore I and pore II variants differ in voltage dependence for activation, kinetics of inactivation, current rectification, and drug resistance.