Fig. 1.

Simplified scheme of the PSII repair cycle. Functional PSII dimers are inactivated by light, and the D1 protein is damaged. After partial disassembly of PSII, the damaged D1 protein is accessed by the FtsH protease, and degraded. Subsequently, the ribosome-nascent D1 chain complex is targeted to the thylakoid membrane, and the D1 protein is co-translationally inserted into the membrane and the PSII complex. The C-terminus of the D1 protein is post-translationally processed, PSII is re-assembled, activated, and the PSII dimers are formed