Molecular Neuropharmacology, Drug Development, Department of Physiology, School of Medicine, Trinity College Dublin, Dublin, Ireland.
J Neurochem. 2014 Aug;130(3):360-73. doi: 10.1111/jnc.12741. Epub 2014 May 19.
The parkin-associated endothelial-like receptor (PAELR, GPR37) is an orphan G protein-coupled receptor that interacts with and is degraded by parkin-mediated ubiquitination. Mutations in parkin are thought to result in PAELR accumulation and increase neuronal cell death in Parkinson's disease. In this study, we find that the protein interacting with C-kinase (PICK1) interacts with PAELR. Specifically, the Postsynaptic density protein-95/Discs large/ZO-1 (PDZ) domain of PICK1 interacted with the last three residues of the c-terminal (ct) located PDZ motif of PAELR. Pull-down assays indicated that recombinant and native PICK1, obtained from heterologous cells and rat brain tissue, respectively, were retained by a glutathione S-transferase fusion of ct-PAELR. Furthermore, coimmunoprecipitation studies isolated a PAELR-PICK1 complex from transiently transfected cells. PICK1 interacts with parkin and our data showed that PICK1 reduces PAELR expression levels in transiently transfected heterologous cells compared to a PICK1 mutant that does not interact with PAELR. Finally, PICK1 over-expression in HEK293 cells reduced cell death induced by PAEALR over-expression during rotenone treatment and these effects of PICK1 were attenuated during inhibition of the proteasome. These results suggest a role for PICK1 in preventing PAELR-induced cell toxicity.
Parkin 相关的内皮样受体（PAELR，GPR37）是一种孤儿 G 蛋白偶联受体，它与 parkin 介导的泛素化相互作用并被其降解。Parkin 突变被认为导致 PAELR 积累，并增加帕金森病中的神经元细胞死亡。在这项研究中，我们发现蛋白相互作用激酶 1（PICK1）与 PAELR 相互作用。具体来说，PICK1 的 Postsynaptic density protein-95/Discs large/ZO-1（PDZ）结构域与位于 PAELR 的 c 端（ct）的最后三个残基的 PDZ 基序相互作用。Pull-down 测定表明，从异源细胞和大鼠脑组织中分别获得的重组和天然 PICK1 与 ct-PAELR 的谷胱甘肽 S-转移酶融合体结合。此外，共免疫沉淀研究从瞬时转染的细胞中分离出 PAELR-PICK1 复合物。PICK1 与 parkin 相互作用，我们的数据表明，与不与 PAELR 相互作用的 PICK1 突变体相比，PICK1 降低了瞬时转染的异源细胞中 PAELR 的表达水平。最后，在 HEK293 细胞中过表达 PICK1 可减少鱼藤酮处理期间过表达 PAEALR 诱导的细胞死亡，并且在蛋白酶体抑制期间 PICK1 的这些作用被减弱。这些结果表明 PICK1 在防止 PAELR 诱导的细胞毒性中起作用。
