Modulation of dopamine D2 receptor signaling by actin-binding protein (ABP-280)
Modulation of dopamine D2 receptor signaling by actin-binding protein (ABP-280)
复制标题
DOI：
10.1124/mol.57.3.446
复制
发表时间：
2000-03-01
影响因子：
3.6
通讯作者：
Zhou, QY
中科院分区：
文献类型：
--
作者：
Li, M;Bermak, JC;Zhou, QY
最近发现，与G蛋白偶联受体结合的蛋白质是受体锚定和信号传递的调节因子。在这项研究中，肌动蛋白结合蛋白280(ABP-280)是一种广泛表达的细胞骨架相关蛋白，在调节细胞形态和运动方面发挥着重要作用，它被发现与多巴胺D-2受体的第三细胞质环有关。这种相互作用的特异性最初是在酵母双杂交筛选中确定的，并通过蛋白质结合得到证实。在缺乏ABP-280的人黑色素瘤细胞中，评估了D-2受体-ABP-280关联的功能意义。D-2受体激动剂对Forsklin刺激的这些细胞内cAMP的产生的抑制作用较弱。D-2受体激活的最大抑制反应也降低。进一步的酵母双杂交实验表明，ABP-280的结合严重依赖于D-2受体第三细胞质环的羧基结构域，在那里有一个潜在的丝氨酸磷酸化位点(S358)。丝氨酸358被天冬氨酸取代以模拟受体磷酸化的效果。该突变株(D(2)S358D)与ABP-280结合能力减弱，与腺苷环化酶偶联。PKC激活也引起D-2受体信号减弱，但仅在含有ABP的细胞中，提示PKC在D-2-ABP关联中起调节作用。这些结果的一个机制可能来自于ABP-280在D-2受体聚集中的作用，正如免疫细胞化学分析在ABP缺乏和充足的细胞中所确定的那样。我们的结果提示了一种通过细胞骨架蛋白相互作用来调节D-2受体信号的新的分子机制。
Proteins that bind to G protein-coupled receptors have recently been identified as regulators of receptor anchoring and signaling. In this study, actin-binding protein 280 (ABP-280), a widely expressed cytoskeleton-associated protein that plays an important role in regulating cell morphology and motility, was found to associate with the third cytoplasmic loop of dopamine D-2 receptors. The specificity of this interaction was originally identified in a yeast two-hybrid screen and confirmed by protein binding. The functional significance of the D-2 receptor-ABP-280 association was evaluated in human melanoma cells lacking ABP-280. D-2 receptor agonists were less potent in inhibiting forskolin-stimulated cAMP production in these cells. Maximal inhibitory responses of D-2 receptor activation were also reduced. Further yeast two-hybrid experiments showed that ABP-280 association is critically dependent on the carboxyl domain of the D-2 receptor third cytoplasmic loop, where there is a potential serine phosphorylation site (S358). Serine 358 was replaced with aspartic acid to mimic the effects of receptor phosphorylation. This mutant (D(2)S358D) displayed compromised binding to ABP-280 and coupling to adenylate cyclase. PKC activation also generated D-2 receptor signaling attenuation, but only in ABP-containing cells, suggesting a PKC regulatory role in D-2-ABP association. A mechanism for these results may be derived from a role of ABP-280 in the clustering of D-2 receptors, as determined by immunocytochemical analysis in ABP-deficient and replete cells. Our results suggest a new molecular mechanism of modulating D-2 receptor signaling by cytoskeletal protein interaction.