Figure 6.

Cofocal micrographs of vertical sections through the inner plexiform layer (IPL) of double-immunostained mouse retinae. Selected areas of the micrographs (frames) are shown at higher magnification, to the right. (A) Gephyrin (red) and the γ2 subunit of the GABA_AR (green) are aggregated in synaptic hot spots, which are often colocalized. (B) GABARAP (red) shows diffuse, punctate distribution in the IPL but is not clustered with gephyrin (green) in synaptic hot spots. The white arrows point to the cell bodies of ganglion cells and show the expression of GABARAP in the cytoplasm. (C) GABARAP (red) and the γ2 subunit of the GABA_AR (green) appear not to be aggregated within the same hot spots. (D) The presynaptic cytomatrix protein bassoon (green), which is clustered at both excitatory and inhibitory synapses, is not colocalized with GABARAP. (Scale bar, 10 μm.) (E) Quantifications of the colocalizations at their correct superpositions and at random superpositions. Only in the case of the γ2 subunit of the GABA_AR and gephyrin was a significant colocalization of puncta observed.