Cell type-specific phosphorylation and proteolysis of a transcriptional regulator controls the G1-to-S transition in a bacterial cell cycle.
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.
Domian
I J
IJ
Department of Developmental Biology, Stanford University School of Medicine, California 94305, USA.
Quon
K C
KC
Shapiro
L
L
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism*; D016934:Caulobacter / Q000166:cytology* / Q000378:metabolism*; D002453:Cell Cycle / Q000502:physiology*; D017931:DNA Primers; D004261:DNA Replication; D004268:DNA-Binding Proteins; D016193:G1 Phase; D006868:Hydrolysis; D016297:Mutagenesis, Site-Directed; D010766:Phosphorylation; D016133:Polymerase Chain Reaction; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism; D016196:S Phase; D017384:Sequence Deletion; D014157:Transcription Factors; D014158:Transcription, Genetic
D001426:Bacterial Proteins; C097706:CtrA protein, Caulobacter; D017931:DNA Primers; D004268:DNA-Binding Proteins; D011994:Recombinant Proteins; D014157:Transcription Factors