Interaction of sugar transporters and signalling proteins in E. coli chemotaxis

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Interactions among cellular signalling and transport networks coordinate responses to changes in the environment, and are thus of outstanding importance for microbial organisms. Here we propose to investigate the interplay between sensing and uptake of nutrients on an example of sugar taxis in Escherichia coli. Although the signal transduction pathway in E. coli chemotaxis is one of the favourite model systems for quantitative analyses of cellular signal processing, only the transport-independent branch of the chemotaxis signalling towards amino acid is well understood. Much less investigated is signalling by sugars, which is coupled to uptake by the two major classes of transporters, the ABC and the PTS transporters. Building upon our recent quantitative characterization of the ABC-transport related sugar signalling, we will study here the least-studied branch of the chemotaxis signalling, by a variety of PTS-imported sugars. To elucidate the molecular mechanisms underlying this type of signalling, we will quantitatively analyze cellular responses to PTS sugars using the intracellular assay of the pathway activity based on FRET. Moreover, we will combine FRET and biochemistry to characterize the regulatory interactions among transporter and chemotaxis proteins that are involved in the PTS-mediated taxis.