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09:40
Imaging G-protein Coupled Receptor (GPCR)-mediated Signaling Events that Control Chemotaxis of Dictyostelium Discoideum
Published on: September 20, 2011
Chemotaxis receptor complexes: from signaling to assembly.
Robert G Endres1, Joseph J Falke, Ned S Wingreen
1Department of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America. rendres@princeton.edu
Plos Computational Biology
|August 7, 2007
Summary
Bacterial chemoreceptor complex size is modeled using in vitro data, revealing how receptor modification, ligand binding, and kinase interactions influence oligomer distribution. This work provides insights into bacterial sensing mechanisms.
Area of Science:
- Microbiology
- Biophysics
- Systems Biology
Background:
- Bacterial chemoreceptors form complexes in the cytoplasmic membrane for sensitive ligand detection.
- The regulation of bacterial chemoreceptor complex size remains poorly understood despite extensive characterization of the signaling network.
Purpose of the Study:
- To develop a model for predicting bacterial chemoreceptor complex size distribution.
- To investigate the factors controlling the assembly and size of receptor complexes in vitro.
Main Methods:
- Utilized in vitro signaling data to model the distribution of Tar receptor complex sizes.
- Modeled complexes as an ensemble of dimers, dimers of dimers, and trimers of dimers.
- Incorporated relative free energies from receptor modification, ligand binding, and CheA interaction into the model.
Main Results:
- The developed model accurately predicts various signaling data, including dose-response curves.
- Model performance was validated against the dependence of receptor activity on receptor density.
- The study demonstrates that receptor modification, ligand binding, and kinase interactions are key determinants of complex size distribution.
Conclusions:
- The size distribution of bacterial chemoreceptor complexes is governed by the relative free energies of different oligomeric states.
- Proposed that in vitro measurements of temporal responses to perturbations in complex free energies can quantify assembly kinetics.
- This research offers a framework for understanding the structural dynamics underlying bacterial chemotaxis signal transduction.
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