A DERIVATIVE OF NADP MOBILIZES CALCIUM STORES INSENSITIVE TO INOSITOL TRISPHOSPHATE AND CYCLIC ADP-RIBOSE
A DERIVATIVE OF NADP MOBILIZES CALCIUM STORES INSENSITIVE TO INOSITOL TRISPHOSPHATE AND CYCLIC ADP-RIBOSE
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DOI：
10.1074/jbc.270.5.2152
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发表时间：
1995-02-03
影响因子：
4.8
通讯作者：
AARHUS, R
中科院分区：
文献类型：
--
作者：
LEE, HC;AARHUS, R
我们先前已经表明，NADP的碱处理产生一种衍生物，其可以从海胆卵匀浆中动员Ca 2+（Clapper，D. L.，Walseth，T. F.、达吉，P. J.，和Lee，H. C.（1987）J.Biol.Chem.262，9561-9568）。在该研究中，纯化活性衍生物，并通过高压液相色谱显示其不同于NADP和NADPH。然而，其质子NMR谱与NADP的质子NMR谱几乎相同。用高分辨质谱法测得其分子离子的质量为743.0510，比相应的NADP离子大一个质量单位，这些结果与活性衍生物为烟酸腺嘌呤二核苷酸磷酸（NAADP）的结果一致。由NAADP诱导的Ca 2+释放可饱和，半最大浓度约为30 nM。由于NADP和烟酸腺嘌呤二核苷酸即使在10-40倍的高浓度下也无效，因此释放是特异性的。NAADP依赖性Ca 2+释放表现出脱敏，并且对肝素和环ADP-核糖（cADPR）的特异性拮抗剂8-氨基-cADPR不敏感。释放机制不需要钙调素，这类似于三磷酸肌醇敏感性释放，但不同于cADPR。NAADP敏感的Ca 2+商店是不同的那些敏感的肌醇三磷酸-或cADPR进一步表明它们的差异在Percoll密度梯度上的分布。将NAADP微量注射到活海胆卵中诱导细胞内Ca 2+的瞬时升高并触发皮质反应，表明NAADP依赖性机制在完整细胞中是有效的。
We have previously shown that alkaline treatment of NADP generates a derivative which can mobilize Ca2+ from sea urchin egg homogenates (Clapper, D. L., Walseth, T. F., Dargie, P. J., and Lee, H. C. (1987) J. Biol. Chem. 262, 9561-9568), In this study, the active derivative was purified and shown by high pressure liquid chromatography to be distinct from NADP and NADPH. However, its proton NMR spectrum was virtually identical to that of NADP. The mass of its molecular ion was measured by high resolution mass spectrometry to be 743.0510, one mass unit larger than the corresponding ion of NADP, These results are consistent with the active derivative being nicotinic acid adenine dinucleotide phosphate (NAADP). Ca2+ release induced by NAADP was saturable with a half-maximal concentration of about 30 nM. The release was specific since NADP and nicotinic acid adenine dinucleotide were ineffective even at 10-40-fold higher concentrations, The NAADP-dependent Ca2+ release showed desensitization and was insensitive to heparin and a specific antagonist of cyclic ADP-ribose (cADPR), 8-amino-cADPR. The release mechanism did not require calmodulin, This is similar to the inositol trisphosphate-sensitive release but distinct from that of cADPR. That the NAADP-sensitive Ca2+ stores were different from those sensitive to inositol trisphosphate- or cADPR was further indicated by their differences in distribution on Percoll density gradients. Microinjection of NAADP into live sea urchin eggs induced transient elevation of intracellular Ca2+ and triggered the cortical reaction, indicating the NAADP dependent mechanism is operative in intact cells.