Gb. Hecht et A. Newton, IDENTIFICATION OF A NOVEL RESPONSE REGULATOR REQUIRED FOR THE SWARMER-TO-STALKED-CELL TRANSITION IN CAULOBACTER-CRESCENTUS, Journal of bacteriology, 177(21), 1995, pp. 6223-6229
The onset of motility late in the Caulobacter crescentus cell cycle de
pends on a signal transduction pathway mediated by the histidine kinas
e PleC and response regulator DivK We now show that pleD, whose functi
on is required for the subsequent loss of motility and stalk formation
by the motile swarmer cell, encodes a 454-residue protein with tandem
N-terminal response regulator domains D1 and D2 and a novel C-termina
l GGDEF domain. The identification of pleD301, a semidominant suppress
or of the pleC Mot phenotype, as a mutation predicted to result in a D
-53-->G change in the D1 domain supports a role for phosphorylation in
the PleD regulator. Disruptions constructed in the pleD open reading
frame demonstrated that the gene is not essential and that the pleC ph
enotype can also be suppressed by a recessive, loss-of-function mutati
on. These results suggest that PleD is part of a signal transduction p
athway controlling stalked-cell differentiation early in the C. cresce
ntus cell cycle.