New research published: Global phosphoproteomics reveals regulatory features
Our new study on the regulatory mechanisms required for cellular acclimation to changing CO2 levels in Synechocystis is online.
Quantitative phosphoproteomics was applied to analyze regulatory features during the acclimation to low CO2 conditions in the model cyanobacterium Synechocystis sp. PCC 6803.
Overall, more than 2500 proteins were quantified in our phosphoproteome study between high carbon and low carbon conditions, equivalent to c. 70% of the Synechocystis theoretical proteome. Interestingly, 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 CO2, whereas the serine/threonine protein kinase SpkC revealed increased phosphorylation levels. The corresponding ΔspkC mutant was characterized and showed decreased ability to acclimate to low CO2 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 CO2 conditions in Synechocystis and possibly among cyanobacteria.
Publication: Spät, P., Barske, T., Maček, B. and Hagemann, M. (2021), Alterations in the CO2 availability induce alterations in the phosphoproteome of the cyanobacterium Synechocystis sp. PCC 6803. New Phytol. https://doi.org/10.1111/nph.17423
Summary of possible consequences of differential protein phosphorylation
during the acclimation to low CO2 levels in Synechocystis sp. PCC 6803.
University of Rostock
Prof. Dr. Martin Hagemann
Department Life, Light and Matter, Interdisciplinary Faculty
martin.hagemann at uni-rostock.de