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The identification of bacterial protein interaction partners pointed out to new intracellular functions of Francisella tularensis glyceraldehyde-3-phosphate dehydrogenase

ABSTRACT: Glyceraldehyde-3-phopshate dehydrogenase (GAPDH) is well-known for its involvement in numerous non-metabolic processes inside the mammalian cells. Alternative functions of prokaryotic GAPDH are mainly deduced from its extracellular localization and the ability to bind to selected host proteins. Data on its participation in intracellular bacterial processes are scarce as there is so far only one study dealing with this issue. We previously reported several evidence that the GAPDH homologue of Francisella tularensis, GapA, might also exert additional non-enzymatic functions. To follow up our former observation, here we decided to find out GapA’s interacting partners within the bacterial proteome to explore its new roles at the intracellular level. The quantitative proteomics approach based on stable isotope labelling of amino acids in cell culture (SILAC) in combination with affinity purification and mass spectrometry enabled us to identify 18 proteins potentially interacting with GapA, six of those interactions were further confirmed by alternative methods. Half of the identified proteins were involved in non-metabolic processes. Further analysis together with the quantitative label-free comparative analysis of proteomes isolated from the wild-type strain and strain with deleted gapA gene suggests that the GapA is implicated in DNA repair processes. The absence of GapA promotes secretion of its most potent interaction partner, the hypothetical protein with peptidase propeptide domain (PepSY) indicating its impact on subcellular distribution of some proteins.

INSTRUMENT(S): Q Exactive

ORGANISM(S): Francisella Tularensis Subsp. Holarctica Fsc200 Bacteria

DISEASE(S): Tularemia

SUBMITTER: Pavel Rehulka

LAB HEAD: Jiri Stulik

PROVIDER: PXD019739 | Pride | 2020-08-31

REPOSITORIES: Pride

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The identification of bacterial protein interaction partners pointed out to new intracellular functions of Francisella tularensis glyceraldehyde-3-phosphate dehydrogenase

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