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Receptor clustering as a cellular mechanism to control sensitivity
D Bray1, M D Levin, C J Morton-Firth
1Department of Zoology, University of Cambridge, UK. d.bray@zoo.cam.ac.uk
Nature
|May 20, 1998
Summary
Bacterial chemotaxis relies on receptor clustering for sensing attractants. This clustering allows Escherichia coli to detect low attractant concentrations and respond across a wide dynamic range.
Area of Science:
- Microbiology
- Biophysics
- Cellular Biology
Background:
- Chemotactic bacteria like Escherichia coli exhibit remarkable sensitivity to attractants, detecting concentrations as low as 5 nM aspartate.
- These bacteria can also sense attractant gradients spanning five orders of magnitude (up to 1 mM aspartate).
Purpose of the Study:
- To investigate the role of chemotactic receptor clustering in bacterial sensitivity and response range.
- To explore how ligand binding and activity propagation within receptor clusters influence chemotaxis.
Main Methods:
- Theoretical modeling of receptor activity propagation within clusters.
- Computational analysis of sensitivity and dynamic range based on receptor organization.
Main Results:
- Increased spread of activity in receptor arrays enhances sensitivity to extracellular ligands.
- However, extensive activity spread significantly diminishes the operational concentration range.
- A combination of clustered and single receptors, with adaptable activity spread, achieves both low detection thresholds and wide dynamic range.
Conclusions:
- Receptor clustering is crucial for the high sensitivity and broad dynamic range of bacterial chemotaxis.
- The proposed model quantitatively explains the observed sensitivity and response range of Escherichia coli to aspartate.
- Adaptive mechanisms in activity spread may further optimize chemotactic responses under varying environmental conditions.