Mammalian Plasma Membrane Ecto-nucleoside Triphosphate Diphosphohydrolase 1, CD39, Is Not Active Intracellularly
Mammalian Plasma Membrane Ecto-nucleoside Triphosphate Diphosphohydrolase 1, CD39, Is Not Active Intracellularly
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哺乳动物质膜外核苷三磷酸二磷酸水解酶 1 (CD39) 在细胞内不活跃
DOI：
10.1074/jbc.m104415200
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发表时间：
2001
期刊：
影响因子：
--
通讯作者：
G. Guidotti
中科院分区：
文献类型：
--
作者：
Xiaotian Zhong;Rajeev Malhotra;Rachel V. Woodruff;G. Guidotti
CD 39是膜结合的胞外核苷三磷酸二磷酸水解酶家族的成员。天然CD 39的活性位点位于细胞质膜的外表面;然而，尚不清楚该酶在沿着分泌途径到达质膜的哪个阶段变得有活性。在这项研究中，蔗糖密度分级进行的CD 39转染COS-7细胞膜表明，CD 39的活性主要存在于质膜。此外，我们已经创建了重组，可溶性版本的CD 39，一个是分泌和其他保留在内质网，以证明CD 39是没有活性，直到它到达质膜在酵母和COS-7细胞。此外，发现COS-7细胞中分泌的活性可溶性CD 39比细胞内保留的非活性形式接受更高程度的N-聚糖加成。当用衣霉素处理COS-7细胞以防止N-糖基化时，在细胞外培养基中未检测到可溶性CD 39，并且在细胞内保持无活性。表面生物素化分析还显示，表面表达的野生型CD 39比细胞内形式接受更高程度的N-糖基化，并且N-糖基化的抑制防止其质膜定位。此外，完整的和毛地黄皂苷通透的COS-7细胞转染的CD 39具有相似的胞外ATP酶活性，进一步支持的结论，只有表面表达的CD 39是酶活性。所有这些数据表明，细胞内的CD 39是无活性的，只有完全糖基化的CD 39具有腺苷三磷酸双磷酸酶活性，并位于细胞表面。
CD39 is a member of the membrane-bound ecto-nucleoside triphosphate diphosphohydrolase family. The active site for native CD39 is located on the outer surface of the cellular plasma membrane; however, it is not yet known at what stage this enzyme becomes active along the secretory pathway to the plasma membrane. In this study, sucrose density fractionations performed on CD39-transfected COS-7 cell membranes suggest that CD39 activity resides primarily in the plasma membrane. Furthermore, we have created recombinant, soluble versions of CD39, one that is secreted and others that are retained in the endoplasmic reticulum, to demonstrate that CD39 is not active until it reaches the plasma membrane both in yeast and COS-7 cells. Moreover, the secreted active soluble CD39 in COS-7 cells is found to receive a higher degree of N-glycan addition than the inactive form retained intracellularly. When COS-7 cells were treated with tunicamycin to preventN-glycosylation, soluble CD39 was not detected in the extracellular medium and remained inactive intracellularly. Surface biotinylation analysis also revealed that surface-expressed wild type CD39 receives a higher degree of N-glycosylation than intracellular forms and that inhibition of N-glycosylation prevents its plasma membrane localization. In addition, both intact and digitonin-permeablized COS-7 cells transfected with CD39 possess similar ecto-ATPase activities, further supporting the conclusion that only surface-expressed CD39 is enzymatically active. All of these data suggest that intracellular CD39 is inactive and that only a fully glycosylated CD39 has apyrase activity and is localized at the cell surface.
影响因子：
15.9
作者：
Marcus, AJ;Broekman, MJ;Maliszewski, CR
通讯作者：
Maliszewski, CR
脑外切腺苷三磷酸双磷酸酶的表征：仅存在一种外切腺苷三磷酸双磷酸酶 (CD39) 基因的证据。
DOI：
10.1016/s0169-328x(97)00066-1
发表时间：
1997
期刊：
Brain research. Molecular brain research
影响因子：
--
作者：
Wang,TF;Rosenberg,PA;Guidotti,G
通讯作者：
Guidotti,G