In Arabidopsis, the Shaker family comprises nine members, which can be segregated into five phylogenetic groups. Group I (KAT1 (AT5G46240) and KAT2 (AT4G18290) ) , group II (AKT1 (AT2G26650) and AKT5 (AT4G32500) ) and group III (AKT2 (AT4G22200) ) can produce homotetrameric hyperpolarization-activated K+channels when expressed alone in heterologous expression systems. In the same conditions, group V (GORK (AT5G37500) , and SKOR (AT3G02850) ) can produce homotetrameric depolarization-activated K+channels. AtKC1, the single member of group IV in Arabidopsis, contributes to the inward K+conductance, probably in association with AKT1 within hetero-meric channels.
