Volume 272, Number 12, Issue of March 21, 1997 pp. 7669-7675
©1997 by The American Society for Biochemistry and Molecular Biology, Inc.

---

Kinetic Properties of Nicotinic Acid Adenine Dinucleotide Phosphate-induced Ca²⁺ Release

(Received for publication, July 10, 1996, and in revised form, October 30, 1996)

From the Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT and the ^¶ School of Biochemistry, University of Birmingham, Birmingham B15 2TT, United Kingdom

Three endogenous molecules have now been shown to release Ca²⁺ in the sea urchin egg: inositol trisphosphate (InsP₃), cyclic adenosine 5-diphosphate ribose (cADPR), and nicotinic acid adenine dinucleotide phosphate (NAADP), a derivative of NADP. While the mechanism through which the first two molecules are able to release Ca²⁺ is established and well characterized with InsP₃ and cADPR-activating InsP₃ and ryanodine receptors, respectively, the newly described NAADP has been shown to release Ca²⁺ via an entirely different mechanism. The most striking feature of this novel Ca²⁺ release mechanism is its inactivation, since subthreshold concentrations of NAADP are able to fully and irreversibly desensitize the channel. In the present study we have investigated the fast kinetics of activation and inactivation of NAADP-induced Ca²⁺ release. NAADP was found to release Ca²⁺ in a biphasic manner, and such release was preceded by a pronounced latent period, which was inversely dependent on concentration. Moreover, the kinetic features of NAADP-induced Ca²⁺ release were not altered by pretreatment with low concentrations of NAADP, although the extent of Ca²⁺ release was greatly affected. Our data suggest that the inactivation of NAADP-induced Ca²⁺ release is an all-or-none phenomenon, and while some receptors have been fully inactivated, those that remain sensitive to NAADP do so without any change in kinetic features.

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				T. Tang, J. Dong, X. Huang, and F. Sun Ca(2+) oscillations induced by a cytosolic sperm protein factor are mediated by a maternal machinery that functions only once in mammalian eggs Development, January 3, 2000; 127(5): 1141 - 1150. [Abstract] [PDF]

				H. Higashida, S. Yokoyama, M. Hashii, M. Taketo, M. Higashida, T. Takayasu, T. Ohshima, S. Takasawa, H. Okamoto, and M. Noda Muscarinic Receptor-mediated Dual Regulation of ADP-ribosyl Cyclase in NG108-15 Neuronal Cell Membranes J. Biol. Chem., December 12, 1997; 272(50): 31272 - 31277. [Abstract] [Full Text] [PDF]

				X. Guo and P. L. Becker Cyclic ADP-ribose-gated Ca2+ Release in Sea Urchin Eggs Requires an Elevated [Ca2+] J. Biol. Chem., July 4, 1997; 272(27): 16984 - 16989. [Abstract] [Full Text] [PDF]