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Rosen, Daniel, Lewis, Alexander M., Mizote, Akiko, Thomas, Justyn M., Aley, Parvinder K., Vasudevan, Sridhar R., Parkesh, Raman, Galione, Antony, Izumi, Minoru, Ganesan, A. 
ORCID: https://orcid.org/0000-0003-4862-7999 and Churchill, Grant C.
(2009)
Analogues of the Nicotinic Acid Adenine Dinucleotide Phosphate (NAADP) Antagonist Ned-19 Indicate Two Binding Sites on the NAADP Receptor.
Journal of Biological Chemistry, 284 (50).
pp. 34930-34934.
ISSN 0021-9258
Abstract
Nicotinic acid adenine dinucleotide phosphate (NAADP) is a Ca2+-releasing messenger. Biological data suggest that its receptor has two binding sites: one high-affinity locking site and one low-affinity opening site. To directly address the presence and function of these putative binding sites, we synthesized and tested analogues of the NAADP antagonist Ned-19. Ned-19 itself inhibits both NAADP-mediated Ca2+ release and NAADP binding. A fluorometry bioassay was used to assess NAADP-mediated Ca2+ release, whereas a radioreceptor assay was used to assess binding to the NAADP receptor (only at the high-affinity site). In Ned-20, the fluorine is para rather than ortho as in Ned-19. Ned-20 does not inhibit NAADP-mediated Ca2+ release but inhibits NAADP binding. Conversely, Ned-19.4 (a methyl ester of Ned-19) inhibits NAADP-mediated Ca2+ release but cannot inhibit NAADP binding. Furthermore, Ned-20 prevents the self-desensitization response characteristic of NAADP in sea urchin eggs, confirming that this response is mediated by a high-affinity allosteric site to which NAADP binds in the radioreceptor assay. Collectively, these data provide the first direct evidence for two binding sites (one high- and one low-affinity) on the NAADP receptor.
| Item Type: | Article |
|---|---|
| Faculty \ School: | Faculty of Science > School of Pharmacy |
| Depositing User: | Users 2731 not found. |
| Date Deposited: | 20 Oct 2011 10:52 |
| Last Modified: | 23 Oct 2022 01:45 |
| URI: | https://ueaeprints.uea.ac.uk/id/eprint/35109 |
| DOI: | 10.1074/jbc.M109.016519 |
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