New sites of action for GIRK and SK channels

GIRK and SK channels, two families of voltage-independent K + channels, have recently been described at synaptic as well as extrasynaptic sites. Luján and colleagues discuss how associated signalling complexes in conjunction with local signals could result in the different functions of these two ion channel families. It was recently discovered that two different types of voltage-insensitive K + channels, G protein-coupled inwardly rectifying K + (GIRK) and small-conductance Ca 2+ -activated K + (SK) channels, are located on dendritic branches, spines and shafts in the postsynaptic densities of excitatory synapses in many central neurons. Together with increases in our knowledge of how these channels are regulated through stable protein–protein interactions in multi-protein complexes, this has added another layer of complexity to our understanding of synaptic transmission and plasticity.