InterPro domain: IPR044803

This entry represents a group of chloroplast thylakoid–associated serine/threonine protein kinases ( 2.7.11.1 ) required for state transition, a process that plays a central role in response to environmental changes and allows to adjust to changing light conditions via the redistribution of light excitation energy between photosystem II (PSII) and photosystem I (PSI) [ 1 , 2 , 3 , 4 ]. Proteins in this entry include STT7 from Chlamydomonas reinhardtii and Arabidopsis STN7/STN8, which phosphorylate light-harvesting complex II outer antennae (LCHII). STN7 is also involved in long‐term adaptations via regulation of chloroplast gene expression [ 5 ]. STN8 is important for the turnover of light‐damaged PSII and the folding of thylakoid membranes. It also plays a role in the fine‐tuning of cyclic electron flow via phosphorylation of the PGRL1‐A protein [ 5 ].

1. Role of chloroplast protein kinase Stt7 in LHCII phosphorylation and state transition in Chlamydomonas. Science 299, 1572-5
2. Phosphoproteomics of Arabidopsis chloroplasts reveals involvement of the STN7 kinase in phosphorylation of nucleoid protein pTAC16. FEBS Lett 586, 1265-71
3. Dynamic thylakoid stacking and state transitions work synergistically to avoid acceptor-side limitation of photosystem I. Nat Plants 7, 87-98
4. Comparative analysis of thylakoid protein complexes in state transition mutants nsi and stn7: focus on PSI and LHCII. Photosynth Res 145, 15-30