Agonist-Activated Bombyx Corazonin Receptor Is Internalized via an Arrestin-Dependent and Clathrin-Independent Pathway

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• 作者：Jingwen Yang ; Zhangfei Shen ; Xue Jiang ; Huipeng Yang ; Haishan Huang ; Lili Jin ; Yajie Chen ; Liangen Shi ; Naiming Zhou
• 刊名：Biochemistry
• 出版年：2016
• 出版时间：July 19, 2016
• 年：2016
• 卷：55
• 期：28
• 页码：3874-3887
• 全文大小：965K
• 年卷期：0
• ISSN：1520-4995

文摘

Agonist-induced internalization plays a key role in the tight regulation of the extent and duration of G protein-coupled receptor signaling. Previously, we have shown that the Bombyx corazonin receptor (BmCrzR) activates both G_αq- and G_αs-dependent signaling cascades. However, the molecular mechanisms involved in the regulation of the internalization and desensitization of BmCrzR remain to be elucidated. Here, vectors for expressing BmCrzR fused with enhanced green fluorescent protein (EGFP) at the C-terminal end were used to further characterize BmCrzR internalization. We found that the BmCrzR heterologously expressed in HEK-293 and BmN cells was rapidly internalized from the plasma membrane into the cytoplasm in a concentration- and time-dependent manner via a β-arrestin (Kurtz)-dependent and clathrin-independent pathway in response to agonist challenge. While most of the internalized receptors were recycled to the cell surface via early endosomes, some others were transported to lysosomes for degradation. Assays using RNA interference revealed that both GRK2 and GRK5 were essentially involved in the regulation of BmCrzR phosphorylation and internalization. Further investigations indicated that the identified cluster of Ser/Thr residues (⁴¹¹TSS⁴¹³) was responsible for GRK-mediated phosphorylation and internalization. This is the first detailed investigation of the internalization and trafficking of Bombyx corazonin receptors.