Why are chemotaxis receptors clustered but other receptors aren’t?
Event details
| Date | 23.03.2015 |
| Hour | 16:15 › 17:15 |
| Speaker | Prof. Ned Wingreen, Princeton University |
| Location | |
| Category | Conferences - Seminars |
The chemotaxis network of bacteria such as E. coli is remarkable for its sensitivity to minute relative changes in chemical concentrations in the environment. Much of this acute sensitivity can be traced to the collective behavior of teams of chemoreceptors on the cell surface. Coupled with a system for adaptation, the advantage for chemotaxis is gain – i.e., small relative changes in chemical concentrations are transduced into large relative changes in signaling activity. However, something is troubling about this simple explanation: in addition to providing gain, the coupling of receptors into teams also increases noise, and the net result is a decrease in the signal-to-noise ratio of the network. Why then are chemoreceptors observed to form cooperative teams? I will present a novel hypothesis that the run-and-tumble chemotactic strategy of bacteria leads to a “noise threshold”, below which noise does not significantly decrease chemotactic velocity, but above which noise dramatically decreases this velocity. I will also discuss other systems in E. coli that call for a biophysical analysis.
Practical information
- General public
- Free
Organizer
- Section de Physique