Maček lab

Maček lab

Post-translational regulation in the autotrophy-to-heterotrophy switch in Synechocystis

Protein phosphorylation on Ser/Thr and Tyr residues has been identified in Synechocystis sp. PCC 6803 as a frequent modification of proteins associated with photosynthesis and enzymes in the central carbon metabolism¹. Strong abundance changes of specific phosphorylation events were detected by quantitative phosphoproteomics in response to the autotrophy-to-heterotrophy switch during resuscitation from nitrogen starvation. Regulatory functions of individual phosphorylation events have recently been demonstrated²; however, the function of most of them is so far unknown.

In the SCyCode consortium, we teamed up with the leading research groups in cyanobacterial metabolism control to characterize the post-translational mechanisms involved in cellular regulation and survival during autotrophy-to-heterotrophy switches. So far, together with the Forchhammer group we could show that phosphorylation is a key to control enzyme activity in glycogen catabolism³, and that specific protein-protein interactions regulate glycogen accumulation⁴ and phycobiliprotein degradation⁵.

Furthermore, together with Hagemann and Hess groups we characterized the substrates of protein kinases relevant in cellular acclimation to carbon limitation⁶, RNA-protein and protein-protein interactions by gradient profiling (GradSeq)⁷ and extended this strategy to the detection of protein-metabolite interactions. Finally, we developed a proteogenomics pipeline to screen our large-scale proteomics data for non-annotated protein coding genes and thus to provide a re-annotated map of the Synechocystis genome for the entire research community.

1 Spät, P., Maček, B. & Forchhammer, K. (2015) Phosphoproteome of the cyanobacterium Synechocystis sp. PCC 6803 and its dynamics during nitrogen starvation. Frontiers in Microbiology 6, doi:10.3389/fmicb.2015.00248
2 Spät, P., Klotz, A., Rexroth, S., Maček, B. & Forchhammer, K. (2018) Chlorosis as a Developmental Program in Cyanobacteria: The Proteomic Fundament for Survival and Awakening. Molecular & cellular proteomics: MCP 17, 1650-1669, doi:10.1074/mcp.RA118.000699
3 Doello, S., Neumann, N., Spät, P., Maček, B & Forchhammer, K. Phosphoglucomutase as central hub in the control of glycogen metabolism (submitted)
4 Orthwein, T, Scholl, J., Spät, P., Lucius, S., Koch, M., Macek, B. Hagemann, M. & Forchhammer, K. (2021) The novel PII-interactor PirC identifies phosphoglycerate mutase as key control point of carbon storage metabolism in cyanobacteria. PNAS e2019988118
5 Krauspe, V., Fahrner, M., Spät, P., Steglich, C., Frankenberg-Dinkel, N., Maček, B., Schilling, O., and Hess, W.R. (2021). Discovery of a small protein factor involved in the coordinated degradation of phycobilisomes in cyanobacteria. Proceedings of the National Academy of Sciences 118, e2012277118.
6 Spät, P., Barske T, Maček, B., and Hagemann, M. Alterations in the CO2 availability induce alterations in the phospho-proteome of the cyanobacterium Synechocystis sp. PCC 6803. New Phytol (accepted)
7 Riediger, M., Spät, P., Bilger, R., Voigt, K., Maček, B., and Hess, W.R. (2020). Analysis of a Photosynthetic Cyanobacterium Rich in Internal Membrane Systems via Gradient Profiling by Sequencing (Grad-seq). The Plant Cell, doi:10.1093/plcell/koaa017

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