Figure 2. Time course of rhodopsin phosphorylation in retinal homogenates.

Phosphorylation of rhodopsin was measured in retinas from wild-type (blue open diamonds), GRK1α (green open inverted triangles), GRK1β (green open ovals), GRK7B (red open circles), GRK7D (red open squares) and GRK7E (red open triangles) fish; open symbols denote light-exposed preparations. In darkness (filled symbols), the extent of phosphorylation was comparable to the background level and less than 10% of that for light-activated rhodopsin. For each symbol, the amount of phosphate (P_i) incorporation is averaged from three independent experiments; error bars show SEM.