Premium
Light‐dependent phosphorylation of D1 reaction centre protein of photosystem II: hypothesis for the functional role in vivo
Author(s) -
Rintamäki Eevi,
Kettunen Reetta,
Tyystjärvi Esa,
Aro EvaMari
Publication year - 1995
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1034/j.1399-3054.1995.930127.x
Subject(s) - phosphorylation , photoinhibition , photosystem ii , thylakoid , protein phosphorylation , biology , microbiology and biotechnology , photosynthetic reaction centre , biochemistry , biophysics , photosynthesis , chloroplast , protein kinase a , gene
Reversible phosphorylation of the D1 reaction centre protein of photosystem II (PSII) occurs in thylakoid membranes of higher plants. The significance of D1 protein phosphorylation in the function of PSII is not yet clear. This paper summarizes the data implying that phosphorylation of D1 protein in higher plants is involved in the regulation of the repair cycle of photoinhibited PSII centres. Photoinhibition of PSII, D1 protein phosphorylation and degradation have been studied in vivo in higher plant leaves acclimated to different growth irradiances. It is shown that photoinhibitory illumination induces maximal phosphorylation of the D1 protein. Under these conditions D1 turnover is also saturated. We postulate that phosphorylation retards the degradation of damaged D1 protein under conditions where rapid replacement by a new D1 copy is not possible. This would protect PSII from total disassembly and degradation of all PSII subunits. We conclude that the phosphorylation of D1 protein and the regulation of D1 protein degradation may have evolved together. Furthermore, these characteristics seem to be related to the highly organized structure of higher‐plant type thylakoid membranes, since the capability to phosphorylate D1 protein is restricted to seed plants.