title: Direct imaging of intracellular signaling components that regulate bacterial chemotaxis.
abstract: The bacterial chemotaxis system regulates the rotational direction of flagellar motors through an intracellular signaling molecule, the phosphorylated form of CheY (CheY-P). The binding of CheY-P to a motor is believed to switch the motor's rotational direction from counterclockwise to clockwise. We demonstrated that the rotational switch of a motor was directly regulated by the binding and dissociation of CheY-P by simultaneously visualizing CheY tagged with green fluorescent protein and the rotational switching of a motor in live cells. The binding of 13 ± 7 CheY-P molecules was sufficient to induce clockwise rotation, and CheY-P molecules bound to and dissociated from a motor within ~100 ms during switching. Thus, we have directly measured the regulation of the output from a signal transduction pathway by intracellular signaling proteins.
authors.affiliation: 1Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Aoba-ku, Sendai 980-8577, Japan.
authors.forename: Hajime
authors.initials: H
authors.lastname: Fukuoka
authors.forename: Takashi
authors.initials: T
authors.lastname: Sagawa
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Inoue
authors.forename: Hiroto
authors.initials: H
authors.lastname: Takahashi
authors.forename: Akihiko
authors.initials: A
authors.lastname: Ishijima
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002633:Chemotaxis; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D029968:Escherichia coli Proteins; D005407:Flagella / Q000378:metabolism / Q000502:physiology; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism*; D015151:Immunoblotting; D042541:Intracellular Space / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D000072236:Methyl-Accepting Chemotaxis Proteins; D008856:Microscopy, Fluorescence / Q000379:methods*; D056004:Molecular Dynamics Simulation; D020409:Molecular Motor Proteins / Q000378:metabolism; D010766:Phosphorylation; D011485:Protein Binding; D012399:Rotation; D015398:Signal Transduction; D059008:Time-Lapse Imaging
chemical_list: D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D008565:Membrane Proteins; D000072236:Methyl-Accepting Chemotaxis Proteins; D020409:Molecular Motor Proteins; C000607606:cheY protein, E coli; D049452:Green Fluorescent Proteins