Cell type-specific phosphorylation and proteolysis of a transcriptional regulator controls the G1-to-S transition in a bacterial cell cycle

Cell. 1997 Aug 8;90(3):415-24. doi: 10.1016/s0092-8674(00)80502-4.


The global transcriptional regulator CtrA controls multiple events in the Caulobacter cell cycle, including the initiation of DNA replication, DNA methylation, cell division, and flagellar biogenesis. CtrA is a member of the response regulator family of two component signal transduction systems and is activated by phosphorylation. We report here that this phosphorylation signal enters the cell cycle at mid S phase. In addition, CtrA function is modulated by temporally and spatially controlled proteolysis. When an active CtrA protein is present at the wrong time in the cell cycle, owing to expression of a mutant CtrA derivative that is active in the absence of phosphorylation and is not turned over during the cell cycle, the G1-to-S transition is blocked and the cell cycle aborts. Thus, both phosphorylation and proteolysis are critical determinants of bacterial cell cycle control in a manner that is analogous to the control of the eukaryotic cell cycle.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Bacterial Proteins / biosynthesis
  • Bacterial Proteins / chemistry
  • Bacterial Proteins / metabolism*
  • Caulobacter / cytology*
  • Caulobacter / metabolism*
  • Cell Cycle / physiology*
  • DNA Primers
  • DNA Replication
  • DNA-Binding Proteins*
  • G1 Phase
  • Hydrolysis
  • Mutagenesis, Site-Directed
  • Phosphorylation
  • Polymerase Chain Reaction
  • Recombinant Proteins / biosynthesis
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / metabolism
  • S Phase
  • Sequence Deletion
  • Transcription Factors*
  • Transcription, Genetic*


  • Bacterial Proteins
  • CtrA protein, Caulobacter
  • DNA Primers
  • DNA-Binding Proteins
  • Recombinant Proteins
  • Transcription Factors