Cytoplasmic localization and efflux of endogenous D-aspartate in pheochromocytoma 12 cells
Cytoplasmic localization and efflux of endogenous D-aspartate in pheochromocytoma 12 cells
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DOI：
10.1016/j.abb.2005.12.008
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发表时间：
2006-02-15
影响因子：
3.9
通讯作者：
Homma, H
中科院分区：
文献类型：
--
作者：
Koyama, H;Adachi, M;Homma, H
在我们之前的报道中[Z。Long， H. Homma, j . a .。Lee， T. Fukushima， T. Santa， T. Iwatsubo， R. Yamada， K. Imai， FEBS通讯，434 (1998)231-235:- Long z， M. Sekine， M. Adachi， T. Furuchi， K. Imai， N. Nimura， H. Homma, Arch。物化学。我们首次证明d -天冬氨酸（D-Asp）实际上是在培养的哺乳动物细胞如PC12、MPT1和GH(3)细胞中合成的。合成后。这种独特的氨基酸在细胞培养过程中自发地、连续地释放到细胞外空间。在目前的研究中，我们表征了PC12细胞中两种不同类型的D-Asp外排。一种是细胞质来源的自发和连续的释放形式，不涉及囊泡来源的胞外流出。内源性D-Asp主要定位于细胞的细胞质。这种形式的D-Asp释放与囊泡多巴胺的胞外量释放形成鲜明对比。另一种形式的外排也是起源于细胞质，通过在低渗刺激下打开的体积敏感的有机阴离子通道发生。有趣的是……后一种形式的外排通过乙酰胆碱刺激而增强。(c) 2005爱思唯尔公司版权所有。
In our previous reports [Z. Long, H. Homma, J.-A. Lee, T. Fukushima, T. Santa, T. Iwatsubo, R. Yamada, K. Imai, FEBS Lett. 434 (1998) 231-235:- Z. Long, M. Sekine, M. Adachi, T. Furuchi, K. Imai, N. Nimura, H. Homma, Arch. Biochem. Biophys. 404 (2002) 92-97], we demonstrated for the first time that D-aspartate (D-Asp) is actually synthesized in cultured mammalian cells such as PC12, MPT1, and GH(3) cells. After its synthesis. this unique amino acid is spontaneously and continuously released into the extracellular space during cell culture. In the current study, we characterized two different types Of D-Asp efflux in PC12 cells. One is a spontaneous and continuous form of release of cytoplasmic origin that does not involve exocytotic efflux of vesicular origin. Endogenous D-Asp is predominantly localized to the cytoplasm of cells. and this form Of D-Asp release presents a striking contrast to exocytotic, quantal discharge of vesicular dopamine. The other form of efflux is also of cytoplasmic origin and occurs through volume-sensitive organic anion channels that are opened upon hyposmotic stimuli. Interestingly.. this latter form of efflux is potentiated by acetylcholine stimulation. (c) 2005 Elsevier Inc. All rights reserved.