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Published on: May 25, 2011
Unique inactivation properties of NAADP-sensitive Ca2+ release
A A Genazzani1, R M Empson, A Galione
1Department of Pharmacology, University of Oxford, United Kingdom.
The Journal of Biological Chemistry
|May 17, 1996
Summary
Nicotinic acid adenine dinucleotide phosphate (NAADP) irreversibly inactivates its own calcium release channel in sea urchin eggs. This unique "one-shot" mechanism, unlike those for InsP3 or cADPR, suggests a role in irreversible cellular events.
Area of Science:
- Cellular Biology
- Biochemistry
- Physiology
Background:
- Cytoplasmic calcium (Ca2+) signals are crucial for cellular processes.
- Intracellular Ca2+ is released via inositol trisphosphate (InsP3) and ryanodine receptors.
- Nicotinic acid adenine dinucleotide phosphate (NAADP) is a newly identified potent Ca2+ releasing agent.
Purpose of the Study:
- To investigate the mechanism of Ca2+ release by NAADP.
- To characterize the properties of the NAADP-sensitive Ca2+ release channel.
- To compare NAADP's action with InsP3 and cyclic adenosine 5'-diphosphate ribose (cADPR).
Main Methods:
- Experiments conducted on intact sea urchin eggs.
- Studies using sea urchin egg homogenates.
- Assays to measure Ca2+ release and channel inactivation.
Main Results:
- NAADP, at non-releasing concentrations, fully and irreversibly inactivates the NAADP-sensitive Ca2+ release mechanism.
- This inactivation was observed in both intact eggs and homogenates.
- InsP3 and cADPR did not share this irreversible inactivation property.
Conclusions:
- NAADP mediates a unique "one-shot" Ca2+ release mechanism.
- This irreversible inactivation suggests a role for NAADP in irreversible cellular events.
- The distinct properties of NAADP signaling differentiate it from InsP3 and cADPR pathways.
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