Correlation between phosphorylation of the chemotaxis protein CheY and its activity at the flagellar motor
- 18 February 1992
- journal article
- Published by American Chemical Society (ACS) in Biochemistry
- Vol. 31 (6), 1821-1826
- https://doi.org/10.1021/bi00121a034
Abstract
Phosphorylation of the chemotaxis protein CheY by its kinase CheA appears to play a central role in the process of signal transduction in bacterial chemotaxis. It is presumed that the role is activation of CheY which results in clockwise (CW) flagellar rotation. The aim of this study was to determine whether this activity of CheY indeed depends on the protein being phosphorylated. Since the phosphorylation of CheY can be detected only in vitro, we studied the ability of CheY to cause CW rotation in an in vitro system, consisting of cytoplasm-free envelopes of Salmonella typhimurium or Escherichia coli having functional flagella. Envelopes containing just buffer rotated only counterclockwise. Inclusion of CheY caused 14% of the rotating envelopes to go CW. This fraction of CW-rotating envelopes was not altered when the phosphate potential in the envelopes was lowered by inclusion of ADP together with CheY in them, indicating that CheY has a certain degree of activity even without being phosphorylated. Attempts to increase the activity of CheY in the envelopes by phosphorylation were not successful. However, when CheY was inserted into partially-lysed cells (semienvelopes) under phosphorylating conditions, the number of CW-rotating cells increased 3-fold. This corresponds to more than a 100-fold increase in the activity of a single CheY molecule upon phosphorylation. It is concluded that nonphosphorylated CheY can interact with the flagellar switch and cause CW rotation, but that this activity is increased by at least 2 orders of magnitude by phosphorylation. This increase in activity requires additional cytoplasmic constituents, the identity of which is not yet known.Keywords
This publication has 31 references indexed in Scilit:
- SIGNAL TRANSDUCTION PATHWAYS INVOLVING PROTEIN PHOSPHORYLATION IN PROKARYOTESAnnual Review of Biochemistry, 1991
- Bacterial Chemotaxis and the Molecular Logic of Intracellular Signal Transduction NetworksAnnual Review of Biophysics and Biophysical Chemistry, 1991
- Pausing, switching and speed fluctuation of the bacterial flagellar motor and their relation to motility and chemotaxisJournal of Molecular Biology, 1990
- Photolabile 1-(2-nitrophenyl)ethyl phosphate esters of adenine nucleotide analogs. Synthesis and mechanism of photolysisJournal of the American Chemical Society, 1988
- Phosphorylation of three proteins in the signaling pathway of bacterial chemotaxisCell, 1988
- Protein phosphorylation in bacterial chemotaxisCell, 1988
- Sensory transduction in bacterial chemotaxis involves phosphotransfer between CHE proteinsBiochemical and Biophysical Research Communications, 1988
- Liposome-mediated transfer of macromolecules into flagellated cell envelopes from bacteriaBiochemistry, 1984
- Isolation, characterization and complementation of Salmonella typhimurium chemotaxis mutantsJournal of Molecular Biology, 1975
- Flagellar rotation and the mechanism of bacterial motilityNature, 1974