Unique Inactivation Properties of NAADP-sensitive Ca
Release (*)
- From the Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, United Kingdom
- § To whom correspondence should be addressed. Tel.: 44-1865-271890; Fax: 44-1865-271853; armando.genazzani{at}pharm.ox.ac.uk.
Abstract
Ca
mobilization from intracellular stores constitutes an important mechanism for generating cytoplasmic Ca
signals. Inositol trisphosphate (InsP
) and ryanodine receptors are the two families of intracellular Ca
release channels that have been identified, which may be regulated by separate intracellular messengers, InsP
and cyclic adenosine 5′-diphosphate ribose, respectively. A third molecule, nicotinic acid adenine dinucleotide phosphate
(NAADP), has recently been recognized as a potent Ca
releasing agent in sea urchin eggs and microsomes. We now report that non-releasing concentrations of NAADP fully and irreversibly
inactivate the NAADP-sensitive Ca
release mechanism. This phenomenon occurred both in intact sea urchin eggs and in homogenates and is not shared by either
InsP
or cyclic adenosine 5′-diphosphate ribose. The novel properties of this Ca
release mechanism, giving a one-shot Ca
release, may be suited to irreversible cellular events.
Footnotes
-
↵* The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore by hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
-
↵1 The abbreviations used are:
- InsP
-
inositol trisphosphate
- cADPR
-
cyclic adenosine 5′-diphosphate ribose
- NAADP
-
nicotinic acid adenine dinucleotide phosphate
- Pipes
-
1,4-piperazinediethanesulfonic acid.
- InsP
-
- Received March 7, 1996.
- © 1996 by The American Society for Biochemistry and Molecular Biology, Inc.
