Angiotensin (1-7) induces MAS receptor internalization.
Angiotensin (1-7) induces MAS receptor internalization.
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DOI：
10.1161/hypertensionaha.111.173344
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发表时间：
2011-08
期刊：
影响因子：
--
通讯作者：
Carretero OA
中科院分区：
文献类型：
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作者：
Gironacci MM;Adamo HP;Corradi G;Santos RA;Ortiz P;Carretero OA
血管紧张素 (Ang) (1-7) 是 G 蛋白偶联受体 Mas 的内源性配体，Mas 是一种与心脏、肾脏和大脑保护反应相关的受体 (R)。生理学证据表明 Mas R 经历激动剂依赖性脱敏，但调节 R 活性的潜在分子机制尚不清楚。我们研究了 Mas R 在 Ang-(1-7) 刺激下脱敏和内化的假设。为此，我们在 Mas R 和荧光蛋白 YFP 之间生成了嵌合体（MasR-YFP）。将MasR-YFP转染的HEK 293T细胞与Ang-(1-7)一起孵育，并通过共聚焦显微镜观察MasR-YFP的相对细胞分布。在静息细胞中，MasR-YFP 主要定位于细胞膜。 5 分钟后，Ang-(1-7) 诱导 MasR-YFP 重新分布至不同大小的细胞内囊泡。随着[125I]Ang-(1-7)内吞作用的时间进程，我们观察到一半的MasR-YFP在10分钟后经历了内吞作用，并且这被Mas R拮抗剂阻断。 MasR-YFP 与 Rab5、早期内体抗原 1 和衔接蛋白复合物 2 共定位，表明 R 通过网格蛋白介导的途径内化，并在 Ang-(1-7) 刺激后靶向早期内体。 MasR-YFP 的一部分也与 Caveolin-1 共定位，表明在某些时候 MasR-YFP 穿过 Caveolin-1 阳性区室。总之，Mas R 在 Ang-(1-7) 刺激下经历内吞作用，这一事件可以解释 Mas R 反应性的脱敏。通过这种方式，Mas R 的活性和密度可以受到细胞的严格控制。
Angiotensin (Ang) (1-7) is the endogenous ligand for the G protein-coupled receptor Mas, a receptor (R) associated with cardiac, renal and cerebral protective responses. Physiological evidence suggests that Mas R undergoes agonist-dependent desensitization, but the underlying molecular mechanism regulating R activity is unknown. We investigated the hypothesis that Mas R desensitizes and internalizes upon stimulation with Ang-(1-7). For this purpose, we generated a chimera between the Mas R and the fluorescent protein YFP (MasR-YFP). MasR-YFP transfected HEK 293T cells were incubated with Ang-(1-7) and the relative cellular distribution of MasR-YFP was observed by confocal microscopy. In resting cells, MasR-YFP was mostly localized to the cell membrane. Ang-(1-7) induced a redistribution of MasR-YFP to intracellular vesicles of various sizes after 5 min. Following the time course of [125I]Ang-(1-7) endocytosis we observed that half of MasR-YFP underwent endocytosis after 10 min and this was blocked by a Mas R antagonist. MasR-YFP colocalized with Rab5, the early endosome antigen 1 and the adaptor protein complex 2, indicating that the R is internalized through a clathrin-mediated pathway and targeted to early endosomes after Ang-(1-7) stimulation. A fraction of MasR-YFP also colocalized with caveolin-1 suggesting that at some point MasR-YFP traverses caveolin-1 positive compartments. In conclusion, Mas R undergoes endocytosis upon stimulation with Ang-(1-7) and this event may explain the desensitization of Mas R responsiveness. In this way, Mas R activity and density may be tightly controlled by the cell.