Molecular properties of crayfish potassium channels

Potassium channel family is the largest group in the ion channel superfamily. Family members are reported in all organisms ranging from bacteria to higher mammals. Potassium channels have important roles in cell growth, termination of action potential and determination of cell shape and resting membrane potential. Presence of crayfish potassium channels has been documented in previous functional studies. However, as the genome of the crayfish is not complete yet, there is limited information about the molecular properties of potassium channels. To reveal potassium channel coding genes in the crayfish, conventional cloning methods have been employed. As a result of the present study, gene sequences have been revealed for an Inward Rectifier Potassium Channel (Kir) and a Calcium-activated (KCa) type of Potassium Channel. Gene sequences show strong similarity to known potassium channels from closely related species and they share characteristic features of the potassium channel family. Revealed genes have been cloned to appropriate expression vectors. Crayfish Kir channel has been expressed in Xenopus oocytes and inward currents have been recorded via two electrode voltage clamp. Compiled data indicates that in crayfish genome are present multiple Potassium Channel genes which have been functionally expressed. It was identified that the cloned genes are belonging to two different potassium channels.