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Alterations in the CO 2 availability induce alterations in the phosphoproteome of the cyanobacterium Synechocystis sp. PCC 6803
Author(s) -
Spät Philipp,
Barske Thomas,
Maček Boris,
Hagemann Martin
Publication year - 2021
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.17423
Subject(s) - synechocystis , phosphoproteomics , phosphorylation , cyanobacteria , proteome , biology , biochemistry , protein phosphorylation , serine , protein subunit , microbiology and biotechnology , protein kinase a , mutant , gene , bacteria , genetics
Summary Cyanobacteria are the only prokaryotes that perform plant‐like oxygenic photosynthesis. They evolved an inorganic carbon‐concentrating mechanism to adapt to low CO 2 conditions. Quantitative phosphoproteomics was applied to analyze regulatory features during the acclimation to low CO 2 conditions in the model cyanobacterium Synechocystis sp. PCC 6803. Overall, more than 2500 proteins were quantified, equivalent to c . 70% of the Synechocystis theoretical proteome. Proteins with changing abundances correlated largely with mRNA expression levels. Functional annotation of the noncorrelating proteins revealed an enrichment of key metabolic processes fundamental for maintaining cellular homeostasis. Furthermore, 105 phosphoproteins harboring over 200 site‐specific phosphorylation events were identified. Subunits of the bicarbonate transporter BCT1 and the redox switch protein CP12 were among phosphoproteins with reduced phosphorylation levels at lower CO 2 , whereas the serine/threonine protein kinase SpkC revealed increased phosphorylation levels. The corresponding Δ spkC mutant was characterized and showed decreased ability to acclimate to low CO 2 conditions. Possible phosphorylation targets of SpkC including a BCT1 subunit were identified by phosphoproteomics. Collectively, our study highlights the importance of posttranscriptional regulation of protein abundances as well as posttranslational regulation by protein phosphorylation for the successful acclimation towards low CO 2 conditions in Synechocystis and possibly among cyanobacteria.