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Imaging G-protein Coupled Receptor (GPCR)-mediated Signaling Events that Control Chemotaxis of Dictyostelium Discoideum
Published on: September 20, 2011
Differences in signalling by directly and indirectly binding ligands in bacterial chemotaxis
Silke Neumann1, Clinton H Hansen, Ned S Wingreen
1Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Heidelberg, Germany.
The EMBO Journal
|September 14, 2010
Summary
Bacteria use direct and indirect ligand binding for chemotaxis. Indirect binding offers better environmental control but a narrower dynamic range, linking nutrient uptake to cell movement.
Area of Science:
- Microbiology
- Biochemistry
- Systems Biology
Background:
- Bacterial chemotaxis relies on transmembrane receptors sensing extracellular stimuli.
- Ligand binding occurs directly or indirectly via periplasmic-binding proteins (BPs).
- BPs link chemotaxis to nutrient utilization, but indirect signaling is less understood.
Purpose of the Study:
- Compare intracellular responses to direct vs. indirect ligand binding.
- Develop a mathematical model for indirect ligand signaling.
- Investigate the physiological importance of ligand binding mechanisms.
Main Methods:
- Comparative analysis of bacterial intracellular responses.
- Development of a novel mathematical model for indirect ligand signaling.
- Examination of signal integration in chemosensory complexes.
Main Results:
- Indirect binding enables enhanced control of ligand sensitivity and chemotaxis-nutrient transport coordination.
- Indirect binding results in a significantly narrower dynamic range compared to direct binding.
- Signal integration is independent of the ligand binding type (direct vs. indirect).
Conclusions:
- The distinction between direct and indirect ligand binding is more critical than receptor abundance.
- Indirect binding provides bacteria with adaptive advantages in nutrient-rich environments.
- Understanding indirect signaling is key to fully elucidating bacterial chemotaxis.
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