Stabilization of polar localization of a chemoreceptor via its covalent modifications and its communication with a different chemoreceptor.
In the chemotaxis of Escherichia coli, polar clustering of the chemoreceptors, the histidine kinase CheA, and the adaptor protein CheW is thought to be involved in signal amplification and adaptation. However, the mechanism that leads to the polar localization of the receptor is still largely unknown. In this study, we examined the effect of receptor covalent modification on the polar localization of the aspartate chemoreceptor Tar fused to green fluorescent protein (GFP). Amidation (and presumably methylation) of Tar-GFP enhanced its own polar localization, although the effect was small. The slight but significant effect of amidation on receptor localization was reinforced by the fact that localization of a noncatalytic mutant version of GFP-CheR that targets to the C-terminal pentapeptide sequence of Tar was similarly facilitated by receptor amidation. Polar localization of the demethylated version of Tar-GFP was also enhanced by increasing levels of the serine chemoreceptor Tsr. The effect of covalent modification on receptor localization by itself may be too small to account for chemotactic adaptation, but receptor modification is suggested to contribute to the molecular assembly of the chemoreceptor/histidine kinase array at a cell pole, presumably by stabilizing the receptor dimer-to-dimer interaction.
Shiomi
Daisuke
D
Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Japan.
Banno
Satomi
S
Homma
Michio
M
Kawagishi
Ikuro
I
D001426:Bacterial Proteins / Q000378:metabolism*; D016764:Cell Polarity; D002628:Chemoreceptor Cells; D004926:Escherichia coli / Q000737:chemistry*; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins / Q000032:analysis / Q000235:genetics; D000071677:Histidine Kinase; D008565:Membrane Proteins / Q000378:metabolism*; D000072236:Methyl-Accepting Chemotaxis Proteins; D008745:Methylation; D008856:Microscopy, Fluorescence; D011956:Receptors, Cell Surface / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000032:analysis / Q000235:genetics
D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D008565:Membrane Proteins; D000072236:Methyl-Accepting Chemotaxis Proteins; D011956:Receptors, Cell Surface; D011993:Recombinant Fusion Proteins; C057331:Tar protein, E coli; C000607604:tsr protein, E coli; D049452:Green Fluorescent Proteins; D000071677:Histidine Kinase; C000607608:cheA protein, E coli