CP22 — Arabidopsis thaliana

Summary

AT1G44575, also known as CP22, NPQ4, or PsbS, encodes a chlorophyll a-b binding protein that localizes to the photosystem II light-harvesting complex and thylakoid membrane. The gene product exhibits chlorophyll and xanthophyll binding, serine-type endopeptidase activity, and autophagy adaptor activity. NPQ4 is associated with non-photochemical quenching, energy dissipation, heat dissipation, and the xanthophyll cycle, as well as with photosynthetic electron transport, light absorption, and chloroplast movement. The gene has been linked to numerous traits including photosynthetic rate, chlorophyll content, quantum yield, leaf thickness, vegetative growth time, seed maturation, sugar and protein content, jasmonic acid content, stomatal resistance, and root length. It is also associated with photoprotection, photoinhibition resistance, drought tolerance, high light stress tolerance, and defense against herbivores and pathogens. Studies of related genes in other species link the family to heat stress tolerance and low night temperature tolerance.