Deciphering the PTSNtr regulatory functions in Caulobacter crescentus
: a pathway controlling cell cycle according to nutrient availability

  • Kenny Petit

Student thesis: Doc typesDoctor of Sciences


A plethora of new regulatory functions associated with the nitrogen-related phosphoenolpyruvate phosphotransferase system (PTSNtr) have been discovered in bacteria these recent years. During my thesis, I characterized at the molecular level the involvement of PTSNtr in the control of Caulobacter crescentus asymmetric cell cycle. Upon nitrogen starvation, we found the overphosphorylated PTSNtr proteins HPrHis~P and EIIANtr~P regulate cell cycle progression by (i) modulating SpoT synthetase and hydrolase activity, and thereby (p)ppGpp levels, as well as by controlling phosphate homeostasis, by interfering with PhoB activity. Our results suggest that HPrHis~P directly inhibits PhoR kinase activity independently of (p)ppGpp. This work illustrates that the PTSNtr coordinates cell cycle and cellular metabolic state by modulating the (p)ppGpp and the Pho regulon. This work might lay the foundation for further studies on the intertwining of phosphate, nitrogen and potentially carbon metabolisms and their consequences on Caulobacter cell cycle.
Date of Award29 May 2017
Original languageEnglish
Awarding Institution
  • University of Namur
SupervisorRegis Hallez (Supervisor), JEAN-JACQUES LETESSON (President), Xavier De Bolle (Jury), Boris Goerke (Jury) & Justine Collier (Jury)


  • Microbiology
  • Caulobacter crescentus
  • Cell cycle regulation
  • Metabolism
  • PTS

Attachment to an Research Institute in UNAMUR


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