title: Hypoxia-induced localization of chemotaxis-related signaling proteins in Vibrio cholerae.
abstract: Vibrio cholerae has three sets of chemotaxis-related signaling proteins, of which only System II has been shown to be involved in chemotaxis. Here, we examined localization of green fluorescent protein (GFP)-fused components of System I. The histidine kinase (CheA1) and the adaptor (CheW0) of System I localized to polar and lateral membrane regions with standing incubation (microaerobic conditions), but their localization was lost after shaking (aerobic conditions). A transmembrane receptor of System I also showed polar and lateral localization with standing incubation. By contrast, GFP-fused components of System II localized constitutively to the flagellated pole. Nitrogen gas, sodium azide or carbonylcyanide m-chlorophenylhydrazone induced localization of CheA1-GFP even with shaking incubation, suggesting that the localization is controlled in response to changes in energy metabolism. Fluorescently labeled tetracysteine-tagged CheA1 also showed azide-induced localization, arguing against artifactual effects of GFP fusions. These results suggest that System I components are assembled into the supramolecular signaling complex in response to reduced cellular energy states, raising the possibility that the System I complex plays a role in sensing and signaling under microaerobic environments, such as in the host intestine.
authors.affiliation: Research Center for Micro-Nano Technology, Hosei University, Koganei, Tokyo, 184-8584, Japan.
authors.forename: Geetha
authors.initials: G
authors.lastname: Hiremath
authors.forename: Akihiro
authors.initials: A
authors.lastname: Hyakutake
authors.forename: Kentaro
authors.initials: K
authors.lastname: Yamamoto
authors.forename: Tatsuaki
authors.initials: T
authors.lastname: Ebisawa
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Nakamura
authors.forename: So-Ichiro
authors.initials: S
authors.lastname: Nishiyama
authors.forename: Michio
authors.initials: M
authors.lastname: Homma
authors.forename: Ikuro
authors.initials: I
authors.lastname: Kawagishi
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002633:Chemotaxis; D004734:Energy Metabolism; D049452:Green Fluorescent Proteins / Q000235:genetics; D000071677:Histidine Kinase; D008565:Membrane Proteins / Q000378:metabolism; D008856:Microscopy, Fluorescence; D010100:Oxygen / Q000502:physiology*; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D015398:Signal Transduction; D014734:Vibrio cholerae / Q000235:genetics* / Q000502:physiology*
chemical_list: D001426:Bacterial Proteins; D008565:Membrane Proteins; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D011494:Protein Kinases; D000071677:Histidine Kinase; D010100:Oxygen