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Schlagwörter:
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Zusammenfassung:
Protein Ser/Thr kinases are posttranslational regulators of key
molecular processes in bacteria, such as cell division and antibiotic
tolerance. Here, we characterize the E. coli toxin YjjJ (HipH), a
putative protein kinase annotated as a member of the family of HipA-like
Ser/Thr kinases, which are involved in antibiotic tolerance. Using
SILAC-based phosphoproteomics we provide experimental evidence that YjjJ
is a Ser/Thr protein kinase and its primary protein substrates are the
ribosomal protein RpmE (L31) and the carbon storage regulator CsrA. YjjJ
activity impacts ribosome assembly, cell division, and central carbon
metabolism but it does not increase antibiotic tolerance as does its
homologue HipA. Intriguingly, overproduction of YjjJ and its
kinase-deficient variant can activate HipA and other kinases, pointing
to a cross talk between Ser/Thr kinases in E. coli. IMPORTANCE
Adaptation to growth condition is the key for bacterial survival, and
protein phosphorylation is one of the strategies adopted to transduce
extracellular signal in physiological response. In a previous work, we
identified YjjJ, a putative kinase, as target of the persistence-related
HipA kinase. Here, we performed the characterization of this putative
kinase, complementing phenotypical analysis with SILAC-based
phosphoproteomics and proteomics. We provide the first experimental
evidence that YjjJ is a Ser/Thr protein kinase, having as primary
protein substrates the ribosomal protein RpmE (L31) and the carbon
storage regulator CsrA. We show that overproduction of YjjJ has a major
influence on bacterial physiology, impacting DNA segregation, cell
division, glycogen production, and ribosome assembly.
