Figure 6. Schematic representation of light-induced PDE translocation on rod outer segment disc membrane. Panel A shows schematic drawing of photoreceptor with specialized rod outer segment domain containing stacks of discs embedded with visual signaling proteins of rhodospin, transducin, and phosphodiesterase (PDE). Abbreviations: rod outer segment (ROS); rod inner segment (RIS). Panel B illustrates enlarged ROS disc membranes with PDE molecules showing a hypothesized random distribution of PDE molecules. Light induces a centripetal translocation of PDE away from the rim-concentrated distribution in dark-adapted states.