Wilson H L, Galione A
University Department of Pharmacology, Oxford University, Mansfield Road, Oxford OX1 3QT, UK.
Biochem J. 1998 May 1;331 ( Pt 3)(Pt 3):837-43. doi: 10.1042/bj3310837.
The sea urchin egg has been used as a system to study calcium-release mechanisms induced by inositol 1,4,5-trisphosphate (IP3), cADP-ribose (cADPR), and more recently, nicotinic acid-adenine dinucleotide phosphate (NAADP). In order that cADPR and NAADP may be established as endogenous messengers for calcium release, the existence of intracellular enzymes capable of metabolizing these molecules must be demonstrated. In addition, intracellular levels of cADPR and NAADP should be under the control of extracellular stimuli. It has been shown that cGMP stimulates the synthesis of cADPR in the sea urchin egg. The present study shows that the sea urchin egg is capable of synthesizing and degrading NAADP. cADPR and NAADP synthetic activities appear to be separate, with different cellular localizations, pH and temperature optima. We suggest that in the sea urchin egg, cADPR and NAADP production may be differentially regulated by receptor-coupled second messengers, with cADPR production being regulated by cGMP and NAADP production modulated by cAMP.
海胆卵已被用作一个系统来研究由肌醇1,4,5 -三磷酸（IP3）、环ADP -核糖（cADPR）以及最近的烟酸腺嘌呤二核苷酸磷酸（NAADP）诱导的钙释放机制。为了使cADPR和NAADP能够被确立为钙释放的内源性信使，必须证明存在能够代谢这些分子的细胞内酶。此外，cADPR和NAADP的细胞内水平应该受到细胞外刺激的控制。已经表明，cGMP刺激海胆卵中cADPR的合成。本研究表明海胆卵能够合成和降解NAADP。cADPR和NAADP的合成活性似乎是分开的，具有不同的细胞定位、最适pH值和温度。我们认为在海胆卵中，cADPR和NAADP的产生可能受到受体偶联的第二信使的差异调节，cADPR的产生由cGMP调节，而NAADP的产生由cAMP调节。
