Identification of a specific transporter on extracellular release of ATP

近年来，ATP通过P2 X和P2 Y嘌呤受体作为细胞功能的调节剂而被熟知。然而，到目前为止，ATP的细胞外释放和相关的Ca^<2+>-信号转导的潜在机制。仍不清楚本专题就是为了澄清这些问题。这些研究包括以下几个单独的部分。首先，在培养的T.在大肠杆菌细胞中，缓激肽通过B2受体介导ATP释放，然后增加Ins（1，4，5）P3的产生，触发内质网Ca^2+释放。Ca^<2+>-信号到达细胞膜，然后膜转运蛋白MRP 1被激活。最后，ATP通过MRP 1转运蛋白输出。在另一项研究中，已经评估了某些Ca^2+信号传导是否有助于缓激肽从培养的输精管平滑肌细胞中诱发的ATP释放。缓激肽通过RyR 2受体介导内质网Ca^2+释放增加。Ca^2+信号被传递到线粒体（Mt），然后，Mt中Ca^2+水平的升高激活了Ca^2+依赖性的ATP酶，并进一步激活了电子传递系统，导致Mt中ATP合成的增强。最后，ATP信号到达细胞膜，促进膜ATP转运系统。总之，这些发现表明ATP输出是由从ER到MT的特征性Ca^<2+>信号传导触发的。

In recent years, ATP is well-known to be served as a modulator of cellular functions via P2X and P2Y purinoceptors. However, so far, the mechanisms underlying the extracellular release of ATP and the related Ca^<2+>-signaling. remains unclear. The present subject was undertaken to clarify these points. The studies consist of separate parts as follows. First, in the study with cultured T. coli cells, bradykinin elicited ATP release mediated by B2 receptors, then, increased Ins(1,4,5)P3 production, triggering Ca^<2+>-release from endoplasmic reticulum. The Ca^<2+>-signal attains to the cell membrane and then, the membrane transporter, MRP1, will be activated. Finally, ATP is exported by MRP1 transporter. CFTR transporter and hemi channels were not involved in the export of ATP evoked by bradykinin.In another study, it has been evaluated whether some Ca^<2+>-signaling contributes to the release of ATP evoked by bradykinin from cultured vas deferens smooth muscle cells. Bradykinin via RyR2 receptor elicits an increase of Ca^<2+> release from ER. The Ca^<2+> signaling was transferred to mitochondria (Mt) and, then, the elevation of Ca^<2+> levels in Mt activates the Ca^<2+>-dependent dehydrogenases and further the electron transfer system resulting in the enhancement of ATP synthesis in Mt. Finally, the ATP signals attain the cell membrane and the membranous ATP transport system is promoted. In conclusion, these findings suggest that the ATP export is triggered by the characteristic Ca^<2+> signaling from ER to MT.