Fig. 3. Subcellular localization of Pcdh- proteins in the synaptic plexiform layers. (A-E) Confocal images of the OPL of Pcdh- ^fusg/fusg retinas double labeled with anti-GFP (green) and antibodies against proteins present in the synapses that photoreceptors form on horizontal and bipolar cells (red). (A) Bassoon, a component of synaptic ribbons in all photoreceptor nerve terminals. (B) PSD-95, a component of rod terminals (spherules). (C) Peanut agglutinin (PNA) labels cone terminals (pedicles). (D) PKC a component of rod bipolar dendrites (arrow). (E) Calbindin, a component of horizontal cell processes (open arrow) that terminate onto rod spherules as well as horizontal cell processes that stratify in the inner OPL (open arrowhead). Pcdh- proteins are present in both spherules and pedicles, and in bipolar and amacrine processes, but are not seen in horizontal cell varicosities (open arrow). (F) A single confocal plane of the IPL of Pcdh- ^fusg/fusg retinas labeled with anti-GFP (green) and antibodies to PSD-95 (red), which marks excitatory postsynaptic sites in this lamina. Fine Pcdh--GFP puncta are distributed throughout the IPL, and are present at but not restricted to synapses. Scale bars: 10 µm.