Characterization of Changes in the GIRK Channel Proteome with Psychostimulants

Activation of G protein-gated inwardly rectifying potassium (GIRK) channels provides a key inhibitory signal in the brain that reduces neuronal firing. Many neurotransmitters in the reward pathway, such as dopamine and GABA, couple to GPCRs that signal through GIRK channels. Prior studies have established a role for GIRK channels in the response to psychostimulants. A complex network of proteins is hypothesized to support drug-dependent changes in trafficking and targeting of GIRK channels to postsynaptic inhibitory synapses, but the identity of these proteins remains largely unknown. To address this, we are using an innovative technique of proximity-dependent biotin identification (i.e., iBio-ID) to identify new proteins in the GIRK channel proteome. Briefly, GIRK2 channels fused to BirA are expressed in vivo, mice are given systemic biotin, biotinylated proteins are purified and then identified using tandem mass spectrometry at the Yale/NIDA Neuroproteomics Center to determine the GIRK channel proteome. Our long-term goal is to characterize the changes in the GIRK channel proteome with psychostimulants. These experiments will provide for the first time a comprehensive list of proteins in the GIRK channel proteome, and lead to the identity of new drug-dependent regulators of GIRK channels.