A transport mechanism for NAADP in a rat basophilic cell line
A transport mechanism for NAADP in a rat basophilic cell line
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DOI：
10.1096/fj.05-5058fje
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发表时间：
2006-01-01
期刊：
影响因子：
4.8
通讯作者：
Genazzani, AA
中科院分区：
文献类型：
--
作者：
Billington, RA;Bellomo, EA;Genazzani, AA
NAADP 是从细胞内储存中释放 Ca2+ 的第二信使。令人惊讶的是，最近已经表明NAADP的细胞外应用能够诱导细胞内Ca2+释放。这是特别重要的，因为已知催化第二信使合成的唯一哺乳动物酶位于细胞外。在本手稿中，我们研究了哺乳动物细胞是否具有能够将这种高电荷分子运输到细胞中的运输系统。事实上，在 RBL-2H3 细胞（一种大鼠嗜碱性细胞系）和 SK-N-BE 细胞（一种神经母细胞瘤细胞系）中，[P-32]NAADP 在细胞内有效转运。 NAADP 转运依赖于 Na+ 和 Ca2+，被双嘧达莫部分阻断，但不受硝基苄基硫代肌苷影响。 RBL-2H3 细胞也转运 [P-32] cADPR，但药理学特征的差异表明 NAADP 转运通过一种新机制进行。最后，细胞外应用 NAADP（而非 NADP）诱导细胞内 Ca2+ 升高。这是 NAADP 被转运到细胞中的首次证明，并强调了 NAADP 与第二信使一起也可能充当自分泌/旁分泌信号的可能性。
NAADP is a second messenger that releases Ca2+ from intracellular stores. Surprisingly, it has been recently shown that extracellular application of NAADP is capable of inducing intracellular Ca2+ release. This is particularly important since the only mammalian enzymes known to catalyze the synthesis of this second messenger are located extracellularly. In the present manuscript, we have investigated whether mammalian cells possess a transport system capable of transporting this highly charged molecule into cells. Indeed, in RBL-2H3 cells, a rat basophilic cell line, and in SK-N-BE cells, a neuroblastoma cell line, [P-32]NAADP is efficiently transported inside cells. NAADP transport is Na+ and Ca2+ dependent, is partially blocked by dipyridamole, but is unaffected by nitrobenzylthioinosine. RBL-2H3 cells also transport [P-32] cADPR, but the differences in the pharmacological profile suggest that NAADP transport proceeds by a novel mechanism. Lastly, extracellular application of NAADP, but not NADP, induced a raise in intracellular Ca2+. This is the first demonstration that NAADP is transported into cells and highlights the possibility that, alongside a second messenger, NAADP might also act as an autocrine/paracrine signal.