Title: GIRK channel activation involves a local rearrangement of a preformed G protein channel complex.

Authors: Inbal Riven, Shachar Iwanir, Eitan Reuveny

Journal, date & volume: Neuron, 2006 Sep 7 , 51, 561-73

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/16950155

Abstract
G protein-coupled signaling is one of the major mechanisms for controlling cellular excitability. One of the main targets for this control at postsynaptic membranes is the G protein-coupled potassium channels (GIRK/Kir3), which generate slow inhibitory postsynaptic potentials following the activation of Pertussis toxin-sensitive G protein-coupled receptors. Using total internal reflection fluorescence (TIRF) microscopy combined with fluorescence resonance energy transfer (FRET), in intact cells, we provide evidence for the existence of a trimeric G protein-channel complex at rest. We show that activation of the channel via the receptor induces a local conformational switch of the G protein to induce channel opening. The presence of such a complex thus provides the means for a precise temporal and highly selective activation of the channel, which is required for fine tuning of neuronal excitability.