G protein-gated inwardly rectifying K+ (GIRK/family 3 of inwardly-rectifying K+) channels contribute to the regulation of membrane excitability in the brain, and play key roles in synaptic plasticity and behaviour (Lüscher et al., 1997; Lüscher & Slesinger, 2010). GIRK channels constitute a critical effector of G protein-coupled receptors that use the Gi/o family of G proteins, thus mediating their slow inhibitory effects (Lüscher & Slesinger, 2010). A major G protein-coupled receptor activating GIRK channels is the metabotropic γ-aminobutyric acid type B (GABAB) receptor (Lüscher et al., 1997). Macromolecular signalling complexes containing GABAB receptors and GIRK channels exist in the brain (Ciruela et al., 2010; David et al., 2006; Fernández-Alacid et al., 2009; Fowler et al., 2007), indicating that their spatial proximity is a critical mechanism to ensure their functional association.
