Involved in photoprotection. Forms a complex with LQY1 that is involved in the repair and reassembly cycle of the PSII-LHCII supercomplex under high-light conditions. May function in guiding the release of psbC from PSII core monomers. Interacts with psbB, psbC and LQY1, but not with psbA or psbD (PubMed:24632535). Found in the stroma lamellae > grana margin > grana core. Not regulated at the transcription level by high light. No visible phenotype, when grown under normal light conditions. Partial loss of PSII capacity after high-light stress.