Lysine acetylation of chloroplast proteins 2

ABSTRACT: In photosynthesis, light is absorbed by the thylakoid embedded light harvesting pigment protein complexes (LHCs) that surround the photosynthetic reaction centers, photosystem II (PSII) and photosystem I (PSI). The distribution of light energy between the photosystems is balanced through state transitions1,2, which refer to the phosphorylation-dependent association of the loosely bound (L) LHCII antenna trimer either to PSII or PSI 3,4. Apart from phosphorylation, other mechanisms regulating state transitions have not been reported this far. In this study we demonstrate that lysine (Lys) acetylation of chloroplast proteins is a prerequisite for state transitions in Arabidopsis thaliana. Knock-out mutants lacking a chloroplast acetyltransferase NSI (At1g32070; AtNSI, SNAT) show selective decreases in the Lys acetylation status of several photosynthetic proteins including PSI, PSII and LHCII subunits. Fluorescence measurements revealed that changes in the wavelength of illumination do not cause state transitions in the nsi mutants even though their LHCII phosphorylation status is not defected. Furthermore, biochemical analyses of thylakoid proteins and protein complexes showed that nsi plants are not able to accumulate the phosphorylation dependent PSI-LHCII megacomplex. Our results manifest that Lys acetylation by NSI has an integral role in the regulation of state transitions in Arabidopsis.

INSTRUMENT(S): Q Exactive

ORGANISM(S): Arabidopsis Thaliana (mouse-ear Cress)

TISSUE(S): Leaf

SUBMITTER: Ines Lassowskat  

LAB HEAD: Iris Finkemeier

PROVIDER: PXD007630 | Pride | 2018-07-03

REPOSITORIES: Pride