Architectures of rod and CC and rhodopsin immuno-EM. (A) Schematic diagram of a mammalian rod showing its cellular compartments: OS, CC, inner segment (IS), nucleus (N), and synapse (SN). The distal tip of the OS directly contacts the retinal pigment epithelial (RPE) cells that phagocytose the shed discs as part of OS renewal. (B, C) Schematic diagrams of cross-sectional (B) and longitudinal (C) views of the CC. BB basal body. (D) An immuno-EM electron micrograph demonstrates the distribution of rhodopsin (detected by C107 Ab followed by 10-nm gold-conjugated secondary Ab). White arrows point to rhodopsin in the CC. Insert: immunoblots of bovine rod OS lysates probed with either anti-rhodopsin C-terminus rabbit Ab C107 or anti-rhodopsin N-terminus monoclonal Ab B6-30. Arrowheads point to monomers, dimers, and higher-order oligomers of rhodopsin.