TITLE:
Regulation of Reversible Dissociation of LHCII from PSII by Phosphorylation in Plants
AUTHORS:
Zhenhai Cui, Yanpeng Wang, Ao Zhang, Lijun Zhang
KEYWORDS:
Light-Harvesting Complex II (LHCII); Phosphorylation; Photosystems; Photoinhibition; Ferredoxin and Thioredoxin System
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.5 No.2,
January
24,
2014
ABSTRACT: LHCII is a crucial
light-harvesting pigment/protein complex in photosystem II (PSII) supercomplex. It also participates in the light
energy redistribution between photosystems and in the photoprotection via its
reversible dissociation with PSII and PSI (photosystem I). This
reversible detachment of LHCII is regulated
by phosphorylation of its own and PSII core protein. Under low light conditions, LHCII is phosphorylated and dissociated with PSII core protein complex and combined with PSI, which
balances the excitation energy
between PSII and PSI; Under high light environment, the
phosphorylation of PSII core proteins
makes LHCII detach from PSII. The dissociated LHCII presents in a free state, which involves in the
thermal dissipation of excess excitation energy. During photodamage, dual
phosphorylations of both PSII core proteins
and LHCII complexes occur. The phosphorylation of D1 is conductive to the disintegration
of photodamaged PSII and the cycle
of repair. In this circumstance, the phosphorylation of LHCII is induced by
reactive oxygen species (ROS) and then the phosphorylated LHCII migrates to
PSI, into the repair cycle of damaged PSII. The
ferredoxin (Fdr) and thioredoxin (Tdr) system may play a possible central role
in the phosphorylation regulation
on LHCII dissociation.