Dataset Information

Lysine acetylation of chloroplast proteins

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: PXD007625 | Pride | 2018-07-03

REPOSITORIES: Pride

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Dataset's files

Source:

			Action	DRS
	160803_C16_015_QHF_PTM_Rev01_16_034_MKO17K_1.raw	Raw
	160803_C16_015_QHF_PTM_Rev01_16_034_MKO17K_2.raw	Raw
	160803_C16_015_QHF_PTM_Rev01_16_034_MKO17K_3.raw	Raw
	160803_C16_015_QHF_PTM_Rev01_16_034_MKO17i_1.raw	Raw
	160803_C16_015_QHF_PTM_Rev01_16_034_MKO17i_2.raw	Raw

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Publications

Chloroplast Acetyltransferase NSI Is Required for State Transitions in <i>Arabidopsis thaliana</i>.

Koskela Minna M MM Brünje Annika A Ivanauskaite Aiste A Grabsztunowicz Magda M Lassowskat Ines I Neumann Ulla U Dinh Trinh V TV Sindlinger Julia J Schwarzer Dirk D Wirtz Markus M Tyystjärvi Esa E Finkemeier Iris I Mulo Paula P

The Plant cell 20180702 8

The amount of light energy received by the photosynthetic reaction centers photosystem II (PSII) and photosystem I (PSI) is balanced through state transitions. Reversible phosphorylation of a light-harvesting antenna trimer (L-LHCII) orchestrates the association between L-LHCII and the photosystems, thus adjusting the amount of excitation energy received by the reaction centers. In this study, we identified the enzyme NUCLEAR SHUTTLE INTERACTING (NSI; AT1G32070) as an active lysine acetyltransfe ...[more]

PMID: 29967049

Similar Datasets

Project description:The regulation of the photosynthetic apparatus in higher plants is highly connected to the organization of the thylakoid membrane into appressed and non-appressed regions. The two photosystems (I and II) are the spatially strongest segregated protein complexes by this thylakoid heterogenous organization, with PSII predominantly present in the appressed membranes (grana), while PSI is confined to the stroma-exposed non-appressed thylakoid membranes (lamellae). Stacking of thylakoid membranes in grana is highly dynamic and influenced by the levels of PSII and LHCII protein phosphorylation which, in turn, are dependent on changes in light intensity and quality and thus, ultimately, on the redox state of the electron transfer chain. Dynamics of this lateral heterogeneity controls the spillover of excitation energy from PSII to PSI and optimizes the photochemistry in constantly fluctuating light conditions. Recently, a family of membrane-integral thylakoid proteins named CURVATURE THYLAKOID 1 (CURT1) have been proposed as new key components in shaping both the width and the number of layers per granum in response to changes in light intensity. CURT1B, in particular, has been known for a long time as a relatively abundant phosphorylated and acetylated protein, but so far the role and dynamics of these post-translational modifications (PTMs) have not been revealed. To this end, we have quantified by means of targeted proteomics the amount of CURT1 proteins and the level of CURT1B PTMs after short-term fluctuating light treatments in wild type Arabidopsis thaliana and the knock-out mutants of the kinases STN7 and STN8 and of the phosphatase TAP38. The CURT1B protein was first localized to a specific curvature domain largely depleted of the chlorophyll-protein complexes. Moreover, we have found that CURT1B is either phosphorylated or acetylated in the N-terminus, but never both. While the level of acetylation is never affected by the light treatments, the phosphorylation increases in light conditions that lead to sudden increase in PSII core protein phosphorylation, and these dynamics are largely abolished in stn8 plants but not in stn7 or tap38. Intriguingly, the phosphorylation dynamics as well as the level of the other CURT1 proteins, are instead highly affected in psb33 plants, which lack LHCII phosphorylation dynamics, and in the psal plants, which show constitutively phosphorylated LHCII. These results provide important information for assessing the relationships between PSII-LHCII phosphorylation, CURT1B phosphorylation and the dynamics of the appressed thylakoids, which in turn allow optimal photosynthesis and provide photoprotection under fluctuations in light intensity.