The G-protein-coupled receptor phosphatase: a protein phosphatase type 2A with a distinct subcellular distribution and substrate specificity.
The G-protein-coupled receptor phosphatase: a protein phosphatase type 2A with a distinct subcellular distribution and substrate specificity.
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G 蛋白偶联受体磷酸酶：2A 型蛋白磷酸酶，具有独特的亚细胞分布和底物特异性。
DOI：
10.1073/pnas.92.18.8343
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发表时间：
1995
影响因子：
11.1
通讯作者：
Lefkowitz,RJ
中科院分区：
文献类型：
--
作者：
Pitcher,JA;Payne,ES;Csortos,C;DePaoli-Roach,AA;Lefkowitz,RJ
G 蛋白偶联受体的磷酸化在调节其功能方面发挥着重要作用。在这项研究中，描述了能够使 G 蛋白偶联受体激酶磷酸化受体去磷酸化的 G 蛋白偶联受体磷酸酶 (GRP)。牛脑的 GRP 活性是 2A 型蛋白磷酸酶 (PP-2A) 的潜在寡聚形式，仅与颗粒部分相关。仅当在鱼精蛋白存在下进行测定或当含有磷酸酶的级分在还原条件下进行冷冻/解冻处理时，才能观察到 GRP 活性。与其作为 PP-2A 家族成员的身份一致，GRP 受到冈田酸的有效抑制，但不受 I-2（1 型蛋白磷酸酶的特异性抑制剂）的有效抑制。膜相关 GRP 溶解，然后在无去污剂的情况下进行凝胶过滤，产生潜在受体磷酸酶活性的 150 kDa 峰值。该磷酸酶的蛋白质印迹分析揭示了AB α C 的可能亚基组成。该亚基组成的PP-2A 先前已被表征为可溶性酶，但观察到可忽略不计的可溶性GRP 活性。 GRP 的亚细胞分布和底物特异性表明它与先前表征的 PP-2A 形式之间存在显着差异。
Phosphorylation of G-protein-coupled receptors plays an important role in regulating their function. In this study the G-protein-coupled receptor phosphatase (GRP) capable of dephosphorylating G-protein-coupled receptor kinase-phosphorylated receptors is described. The GRP activity of bovine brain is a latent oligomeric form of protein phosphatase type 2A (PP-2A) exclusively associated with the particulate fraction. GRP activity is observed only when assayed in the presence of protamine or when phosphatase-containing fractions are subjected to freeze/thaw treatment under reducing conditions. Consistent with its identification as a member of the PP-2A family, the GRP is potently inhibited by okadaic acid but not by I-2, the specific inhibitor of protein phosphatase type 1. Solubilization of the membrane-associated GRP followed by gel filtration in the absence of detergent yields a 150-kDa peak of latent receptor phosphatase activity. Western blot analysis of this phosphatase reveals a likely subunit composition of AB alpha C. PP-2A of this subunit composition has previously been characterized as a soluble enzyme, yet negligible soluble GRP activity was observed. The subcellular distribution and substrate specificity of the GRP suggests significant differences between it and previously characterized forms of PP-2A.