Antidepressants Increase β-Arrestin2 Ubiquitinylation and Degradation by the Proteasomal Pathway in C6 Rat Glioma Cells
Antidepressants Increase β-Arrestin2 Ubiquitinylation and Degradation by the Proteasomal Pathway in C6 Rat Glioma Cells
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DOI：
10.1124/jpet.109.160218
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发表时间：
2010-03-01
影响因子：
3.5
通讯作者：
Avissar, Sofia
中科院分区：
文献类型：
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作者：
Golan, Moran;Schreiber, Gabriel;Avissar, Sofia
β-抑制蛋白，G蛋白偶联受体-G蛋白偶联和受体脱敏和内化的调节剂，也作为介导细胞信号传导事件的支架蛋白发挥作用。β-Arrestin 1以前被我们认为与抑郁症的病理生理学和抗抑郁药（AD）的作用机制有关。广泛表达的β-arrestins 1和2在结构上高度同源。人们对这两种蛋白质进行了广泛的研究，以确定它们是否在受体信号传导中发挥不同的作用。在这项研究中，我们表明，治疗C6大鼠胶质瘤细胞与各种类型的广告3天，导致β-arrestin 2水平下降。相反，β-arrestin 2 mRNA的表达被发现由AD上调。为了阐明这些相反作用的机制，研究了几种可能的β-arrestin 2转录后事件和修饰。用靶向β-arrestin 1的短发夹RNA转染的C-6大鼠胶质瘤细胞显示出类似的AD对β-arrestin 2水平的影响。AD诱导的β-arrestin 2蛋白水平下降不是由于胞质膜转位。免疫沉淀实验表明，AD能够增加泛素与β-arrestin 2的免疫共沉淀。AD诱导的β-arrestin 2泛素化增加导致其通过蛋白酶体途径降解，因为蛋白酶体抑制剂N-[（苯甲氧基）羰基]-L-亮氨酰-N-[（1 S）-1-甲酰基-3-甲基丁基]-L-亮氨酰胺（MG-132）阻止抗抑郁药诱导的β-arrestin 2蛋白水平降低。
beta-Arrestins, regulators of G protein-coupled receptor-G protein coupling and receptor desensitization and internalization, function also as scaffolding proteins mediating cellular signaling events. beta-Arrestin1 was previously implicated by us in the pathophysiology of depression and in the mechanism of action of antidepressants (ADs). The ubiquitously expressed beta-arrestins1 and 2 are structurally highly homologous. There has been extensive investigation of these two proteins to determine whether they serve different roles in receptor signaling. In this study, we show that treatment of C 6 rat glioma cells with ADs of various types for 3 days resulted in decreased beta-arrestin2 levels. In contrast, beta-arrestin2 mRNA expression was found to be up-regulated by ADs. To unravel the mechanism for these opposite effects several possible beta-arrestin2 post-transcriptional events and modifications were examined. C-6 rat glioma cells transfected with beta-arrestin1-targeted short hairpin RNA showed similar effects of ADs on beta-arrestin2 levels. AD-induced decreases in beta-arrestin2 protein levels were not due to cytosolic membrane translocation. Immunoprecipitation experiments showed that ADs were able to increase coimmunoprecipitation of ubiquitin with beta-arrestin2. AD-induced increases in beta-arrestin2 ubiquitinylation led to its degradation by the proteasomal pathway, as the proteasome inhibitor N-[(phenylmethoxy) carbonyl]-L-leucyl-N-[(1S)-1-formyl-3-methylbutyl]-L-leucinamide (MG-132) prevented antidepressant-induced decreases in beta-arrestin2 protein levels.