Figure 11. Schematic diagram of light-regulated disk assembly.

A. Rods housed in an alternating light-dark cycle (top panel) will vary the rate of disk assembly and displacement (second panel) in response to the phase of the cycle [6], [7]. Since endogenous rhodopsin density in OS membranes is constant, the rate of rhodopsin incorporation (third panel) must change in phase with the lighting cycle and disk assembly. By contrast, Rho-eGFP appears to have a relatively constant rate of incorporation into the OS (bottom panel). This would then lead to a periodic variation in Rho-eGFP content, with higher densities assembled at night. B. Schematic diagram illustrating the density variation of Rho-eGFP (green) throughout a light cycle and the absence of variation in endogenous rhodopsin (red). The length of the lighting cycle and the size of the cell are not to scale.