MICROHETEROGENEITY IN HETEROMULTIMERIC ASSEMBLIES FORMED BY SHAKER (KV1) AND SHAW (KV3) SUBFAMILIES OF VOLTAGE-GATED K+ CHANNELS

Single K+ channels were recorded in Xenopus oocytes injected with a 1: 1 mixture of mRNAs coding for NGK1 (Kv1.2) and NGK2 (Kv3.1a) voltage-d ependent K+ channels. A new class of channels of 18 pS conductance was observed, and was designated as NGK1,2 channels. According to their p roperties of activation voltages and open life times, four types of NG K1,2 channels with microheterogeneity were detected. The results sugge st that voltage-dependent NGK1 Shaker and NGK2 Shaw K+ channels, from different subfamilies, assemble to form heteromultimeric K+ channels, giving rise to a mosaic of characteristics inherited from two parental channels.