Adenosine deaminase affects ligand-induced signalling by interacting with cell surface adenosine receptors
Adenosine deaminase affects ligand-induced signalling by interacting with cell surface adenosine receptors
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DOI：
10.1016/0014-5793(96)00023-3
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发表时间：
1996-02-19
期刊：
影响因子：
3.5
通讯作者：
Franco, R
中科院分区：
文献类型：
--
作者：
Ciruela, F;Saura, C;Franco, R
腺苷脱氨酶（ADA）不仅是一种胞浆酶，也可以作为一种胞外酶被发现。在质膜上，已鉴定出一种腺苷脱氨酶结合蛋白（CD 26，也称为二肽基肽酶IV），但这种ADA/CD 26复合物的功能作用尚不清楚。通过共聚焦显微镜、亲和层析和共沉淀实验，我们证明A（1）腺苷受体（A（1）R）是第二个外膜ADA结合蛋白。ADA与A（1）R的结合增加了其对配体的亲和力，因此表明ADA是A（1）R和异三聚体G蛋白之间有效偶联所必需的。这一点得到了以下事实的证实：阿萨独立于其催化行为，通过A（1）R增强配体诱导的第二信使产生。这些发现表明，细胞表面的外腺苷脱氨酶除了切割腺苷外，还通过A（1）R促进信号转导。
Adenosine deaminase (ADA) is not only a cytosolic enzyme but can be found as an ecto-enzyme. At the plasma membrane, an adenosine deaminase binding protein (CD26, also known as dipeptidylpeptidase IV) has been identified but the functional role of this ADA/CD26 complex is unclear. Here by confocal microscopy, affinity chromatography and coprecipitation experiments we show that A(1) adenosine receptor (A(1)R) is a second ecto-ADA binding protein. Binding of ADA to A(1)R increased its affinity for the ligand thus suggesting that ADA was needed for an effective coupling between A(1)R and heterotrineric G proteins. This was confirmed by the fact that ASA, independently of its catalytic behaviour, enhanced the ligand-induced second messenger production via A(1)R. These findings demonstrate that, apart from the cleavage of adenosine, a further role of ecto-adenosine deaminase on the cell surface is to facilitate the signal transduction via A(1)R.