Primary structure and functional expression of a novel non-selective cation channel.

A non-selective cation channel is believed to play important roles in various tissues. A novel complementary DNA encoding non-selective cation channel was isolated from MIN6, a mouse insulin secreting beta-cell line. This channel (mNSC1) conducts predominantly monovalent cations in Xenopus oocytes and is selective for cations over anions (PK/PCl = 10). The current was completely blocked by lanthanum and niflumate. The mNSC1 of 423 amino acids contains a characteristic leucine repeat and unique membrane topology. The messenger RNA of this channel are abundant in the brain, heart, and lung. We may therefore conclude that studies with this channel will provide important information for understanding physiological functions of the excitable cells as well as non-excitable epithelia.