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Dynamics of cellular NO-cGMP signaling
1Wolfson Institute for Biomedical Research, University College London, Gower Street, London WC1E 6BT, UK. john.garthwaite@ucl.ac.uk
Frontiers in Bioscience : a Journal and Virtual Library
|March 17, 2005
Summary
Nitric oxide (NO) signals are brief, localized, and low-amplitude, yet cellular receptors are highly sensitive. Variations in receptor desensitization and cGMP hydrolysis explain diverse cellular responses to NO.
Area of Science:
- Cellular biology
- Molecular signaling
- Biochemistry
Background:
- The cellular mechanisms of nitric oxide (NO) signaling remain incompletely understood.
- Recent research has begun to elucidate the fundamental properties of NO signaling pathways.
Purpose of the Study:
- To review recent findings on the cellular workings of the NO signaling pathway.
- To introduce a kinetic model for guanylyl cyclase (GC)-coupled NO receptors.
Main Methods:
- Review of recent scientific literature.
- Introduction of a kinetic model for NO receptor function.
- Analysis of cellular cGMP responses.
Main Results:
- NO signals are discrete, short-lived (seconds), low-amplitude (nanomolar), and spatially confined (microns).
- GC-coupled NO receptors exhibit sub-second kinetics and high sensitivity to low nanomolar NO.
- Cellular cGMP responses vary due to differences in receptor desensitization and phosphodiesterase activity.
Conclusions:
- NO receptors are well-tuned to detect transient, low-concentration NO signals.
- Cellular diversity in cGMP responses is influenced by receptor modulation and cGMP hydrolysis rates.
- Factors like Ca2+, ATP, phosphorylation, and protein interactions modulate NO receptor function.