Regulation of thylakoid protein phosphorylation by high‐energy‐state quenching

Abstract
The possible co‐regulation of light‐induced protein phosphorylation by the redox state of plastoquinone and the transthylakoid ΔpH was investigated in isolated pea chloroplasts. Incorporation of γ‐32P‐labelled ATP into the LHC‐II and 9 kDa phosphoproteins in the coupled state was reduced by 54 and 28%, respectively, when compared to the uncoupled state. Selective inhibition of energy‐state‐dependent quenching of chlorophyll fluorescence by antimycin A in the coupled state greatly reduced this inhibition of protein phosphorylation and subsequent quenching of chlorophyll fluorescence. These results suggest that the protein kinase(s) involved in phosphorylation of the LHC‐II and 9 kDa phosphoproteins is regulated by either the energy state of the thylakoid membrane or the redox state of some component of the electron‐transport chain, rather than by ΔpH per se.

This publication has 17 references indexed in Scilit: