Fig. 3

Differential co-clustering of GIRK2 with other GIRK subunits in CA1 pyramidal cells. Electron micrographs of the stratum radiatum of the hippocampal CA1 field showing double labelling for GIRK2 (5 nm)/GIRK1 (10 nm) and GIRK2 (5 nm)/GIRK3 (10 nm), as detected using the SDS-FRL technique. A–C Immunoparticles for GIRK2 co-clustered with those for GIRK1 (green ellipses/circles) in dendritic spines (s), oblique dendrites (oDen), and axon terminals (at). D–G Immunoparticles for GIRK2 (blue ellipses/circles) were segregated from GIRK3 clusters (black ellipses/circles) or immunoparticles (black arrows) in dendritic spines (s), oblique dendrites (oDen), and axon terminals (at). H Quantitative analysis using the SDS-FRL technique, showing the nearest neighbour distance (NND) between immunoparticles for GIRK2 to GIRK1 and immunoparticles for GIRK2 to GIRK3 in spines and dendritic shafts, as well as presynaptically in axon terminals and their active zones. The distances between immunoparticles for GIRK2 and GIRK1 are significantly shorter in all neuronal compartments than those between GIRK2 and GIRK3 (Mann–Whitney test, ****p < 0.0001). Thus, this analysis demonstrated a spatial association between GIRK2 and GIRK1, but not between GIRK2 and GIRK3. Scale bars: A–G, 0.2 μm