Figure 8: Potential model of the repair cycle of a photo-damaged D1 protein.

The exposure of cells to stress conditions in the presence of light often results in irreversible oxidation of D1, which subsequently needs to be replaced. In the repair process, several proteases and chlorophyll-binding proteins are recruited at different stages, as previously suggested^39,40. The observed co-expression suggests a cooperative role of FtsH proteases and high-light induced proteins (HLIPs) in the D1 proteolysis, as indicated in the scheme. The color of the different subunits and recruited proteins symbolizes their pertinence to differently regulated gene clusters.