Moccia F, Billington R A, Santella Luigia
Laboratory of Cell Signaling, Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy.
Biochem Biophys Res Commun. 2006 Sep 22;348(2):329-36. doi: 10.1016/j.bbrc.2006.05.157. Epub 2006 Jun 5.
The recently discovered second messenger nicotinic acid adenine dinucleotide phosphate (NAADP) is central to the onset of intracellular Ca2+ signals induced by several stimuli, including fertilization. The nature of the Ca2+ pool mobilized by NAADP is still controversial. Depending on the cell type, NAADP may target either an acidic compartment with lysosomal properties or ryanodine receptors (RyRs) on endoplasmic reticulum. In addition, NAADP elicits a robust Ca2+ influx into starfish oocytes by activating a Ca2+-mediated current across the plasma membrane. In the present study, we employed the single-electrode intracellular recording technique to assess the involvement of either acidic organelles or RyRs in NAADP-elicited Ca2+ entry. We found that neither drugs which interfere with acidic compartments nor inhibitors of RyRs affected NAADP-induced depolarization. These data further support the hypothesis that a yet unidentified plasma membrane Ca2+ channel is the target of NAADP in starfish oocytes.
最近发现的第二信使烟酰胺腺嘌呤二核苷酸磷酸（NAADP）在包括受精在内的多种刺激所诱导的细胞内Ca2+信号的起始过程中起着核心作用。由NAADP动员的Ca2+池的性质仍存在争议。根据细胞类型的不同，NAADP可能靶向具有溶酶体特性的酸性区室或内质网上的兰尼碱受体（RyRs）。此外，NAADP通过激活跨质膜的Ca2+介导电流，引发海星卵母细胞中强大的Ca2+内流。在本研究中，我们采用单电极细胞内记录技术来评估酸性细胞器或RyRs在NAADP引发的Ca2+内流中的作用。我们发现，干扰酸性区室的药物或RyRs抑制剂均不影响NAADP诱导的去极化。这些数据进一步支持了以下假说：一种尚未确定的质膜Ca2+通道是海星卵母细胞中NAADP的作用靶点。
