Profiling of yeast Saccharomyces cerevisiae mitochondrial AMPylome reveals a regulation of ATP synthase coupling trough subunit δ

The adenylation (AMPylation) of proteins as a posttranslational modification is used by bacteria during infection of host cells. These new virulence factors - AMPylases mainly belonging to the FIC domain containing proteins and constitute a potential drug target. Human FIC protein (HYPE) controls the activity of BiP chaperone under endoplasmic reticulum stress. No FIC family proteins have yet been identified in yeast Saccharomyces cerevisiae . The second family of AMPylases are SelO proteins which control the redox homeostasis in mitochondria and chloroplasts. We describe here the first global screening of AMPylated proteins in yeast S. cerevisiae mitochondrial proteome from wild type and SelO (Fmp40) lacking cells. Through quantitative mass-spectrometry-based proteomics, we identified a total of 169 AMPylated proteins in mitochondria while AMPylated peptides of 115 proteins were identified in fmp40Δ mitochondria, indicating on the presence of another, besides Fmp40, not yet identified AMPylase in yeast. We confirmed AMPylation of Atp1, Atp2, Atp3 and Atp16 subunits of mitochondrial ATP synthase by western blotting. Interestingly, we found AMPylation and phosphorylation of many residues, what indicates on the complex regulation of the ATP synthase activity. We confirmed the importance of one of such residues in Atp16, showing that its post-translational modification serves to regulate ATP synthase and OXPHOS coupling in both fermentative and respiratory growth conditions. This regulation serves to maintain the proper potential of the inner mitochondrial membrane, particularly under conditions of fermentative growth. This dataset represents the first library of AMPylated mitochondrial yeast proteins reported to date and supplements the AMPylome of human chronic lymphocytic leukemia cell line from human HYPE containing and HYPE lacking cells. The data represents a foundation for substrate specific investigations that can ultimately decipher the biological role of the AMPylation in the mitochondria.