FBS Colloquia No.359Laboratory of Nano-Biophysics

What shape are the bacterial chemotaxis receptor clusters at the cell poles?

E. coli use a chemotaxis system to swim toward a more favorite environment. External stimuli are recognized by five types of chemotaxis receptors (Tar, Tsr, Trg, Tap, and Aer). These receptors form large receptor clusters (more than 10,000 molecules) together with histidine kinase CheA and adapter protein CheW at the cell poles. Electron microscopy has shown that receptors clusters as large array structure at the cell poles. To investigate the structure and state of receptor clusters during signal transduction in a living cell, we used GFP fusions of receptors or chemotaxis proteins and analyzed these fluorescence images in three dimensions using a deconvolution method. The receptor cluster were observed as ring-like structures at the cell poles. We want to discuss these results in this colloquium.