EVIDENCE FOR LIGHT-DEPENDENT AND LIGHT-INDEPENDENT PROTEIN DEPHOSPHORYLATION IN CHLOROPLASTS

A number of photosystem II (PSII) associated proteins, including core proteins D1, D2 and CP43, and several proteins of the LHCII complex, a re phosphorylated by a thylakoid-bound, redox-regulated kinase(s), We demonstrate here that the compound propyl gallate is an effective inhi bitor of LHCII phosphorylation in vivo while having little effect on P SII core protein phosphorylation. Using this inhibitor, we demonstrate that LHCII dephosphorylation is insensitive to light in vivo, Taken t ogether with our previous conclusion (Elich et al., EMBO J. 12 (1993) 4857-4862) that PSII core protein dephosphorylation is light-stimulate d, our data suggest the presence of multiple phosphatases responsible for thylakoid protein dephosphorylation in vivo. (C) 1997 Federation o f European Biochemical Societies.