A novel feature of the multistep phosphorelay in Escherichia coli: a revised model of the RcsC --> YojN --> RcsB signalling pathway implicated in capsular synthesis and swarming behaviour.
In this study, we re-investigated the previously characterized RcsC (sensor His-kinase) --> RcsB (response regulator) phosphorelay system that is involved in the regulation of capsular polysaccharide synthesis in Escherichia coli. The previously proposed model hypothesized the occurrence of a direct phosphotransfer from RcsC to RcsB in response to an unknown external stimulus. As judged from the current general view as to the His --> Asp phosphorelay, this RcsC --> RcsB framework is somewhat puzzling, because RcsC appears to contain both a His-kinase domain and a receiver domain, but not a histidine (His)-containing phosphotransmitter domain (e.g. HPt domain). We thus suspected that an as yet unknown mechanism might be underlying in this particular His --> Asp phosphorelay system. Here, we provide several lines of in vivo and in vitro evidence that a novel and unique His-containing phosphotransmitter (named YojN) is essential for this signalling system. A revised model is proposed in which the multistep RcsC --> YojN --> RcsB phosphorelay is implicated. It was also demonstrated that this complex signalling system is somehow involved in the modulation of a characteristic behaviour of E. coli cells during colony formation on the surface of agar plates, namely swarming.
Takeda
S
S
Laboratory of Molecular Microbiology, School of Agriculture, Nagoya University, Chikusa-ku, Nagoya 464-8601, Japan.
Fujisawa
Y
Y
Matsubara
M
M
Aiba
H
H
Mizuno
T
T
D000595:Amino Acid Sequence; D016667:Bacterial Capsules / Q000096:biosynthesis*; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D003470:Culture Media; D004926:Escherichia coli / Q000235:genetics / Q000502:physiology*; D029968:Escherichia coli Proteins; D015964:Gene Expression Regulation, Bacterial; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes; D010749:Phosphoprotein Phosphatases; D010766:Phosphorylation; D010770:Phosphotransferases; D010957:Plasmids; D011494:Protein Kinases; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
D001426:Bacterial Proteins; D003470:Culture Media; D029968:Escherichia coli Proteins; D009097:Multienzyme Complexes; C489568:RcsB protein, E coli; D014157:Transcription Factors; C489728:rcsC protein, E coli; C074889:RcsB protein, Bacteria; D010770:Phosphotransferases; D011494:Protein Kinases; C434271:rcsD protein, E coli; D010749:Phosphoprotein Phosphatases