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Agonist-dependent trafficking of alpha2-adrenoceptor subtypes: dependence on receptor subtype and employed agonist.
European Journal of Cell Biology ( IF 4.5 ) Pub Date : 2003-06-13 , DOI: 10.1078/0171-9335-00311
Tuire Olli-Lähdesmäki 1 , Mika Scheinin , Katariina Pohjanoksa , Jaana Kallio
Affiliation  

Many G protein-coupled receptors (GPCRs) are internalized from the plasma membrane after agonist exposure. Previously, marked agonist-induced internalization of human alpha2A- and alpha2B-adrenergic receptors (AR) was observed in transfected neuronal rat pheochromocytoma (PC12) cells; alpha2A- and alpha2B-AR were internalized into partly distinct intracellular vesicles (Olli-Lähdesmäki et al., J. Neurosci. 19, 9281-9288, 1999). In this paper, the extent of alpha2-AR internalization was quantitated in human embryonic kidney (HEK-293) and PC12 cells by combined application of cell surface biotinylation and ELISA methods, which allow measurement of protein trafficking in intact, differentiated and undifferentiated cells. Significant subtype-specific (but not cell type-dependent) trafficking of human alpha2-AR was observed by quantitation and immunocytochemistry. Agonist-induced sequestration of alpha2B-AR was markedly reduced after blocking the formation of clathrin-coated vesicles by hyperosmotic sucrose pretreatment. The sequestration of alpha2A-AR was partly inhibited after sucrose pretreatment but could be further reduced after inhibiting the formation of both clathrin-coated and caveolin vesicles by combined pretreatment with hyperosmotic sucrose and filipin. Differences were also observed in the recycling of alpha2A- and alpha2B-AR. The extent of maximal agonist-induced sequestration in PC12 cells was not directly dependent on relative agonist efficacy.

中文翻译:

依赖激动剂的α2-肾上腺素受体亚型的贩运:对受体亚型的依赖和所使用的激动剂。

激动剂暴露后,许多G蛋白偶联受体(GPCR)从质膜内化。以前,在转染的神经元大鼠嗜铬细胞瘤(PC12)细胞中观察到激动剂诱导的人α2A和α2B肾上腺素能受体(AR)的内在化。将α2A-和α2B-AR内化到部分不同的细胞内囊泡中(Olli-Lähdesmäki等,J.Neurosci.19,9281-9288,1999)。在本文中,通过结合应用细胞表面生物素化和ELISA方法对人类胚胎肾脏(HEK-293)和PC12细胞中的α2-AR内化程度进行了定量,从而可以测量完整,分化和未分化细胞中的蛋白质运输。通过定量和免疫细胞化学观察到人类α2-AR的重要亚型特异性(但不是细胞类型依赖性)运输。通过高渗蔗糖预处理阻止网格蛋白包被的囊泡形成后,激动剂诱导的螯合α2B-AR明显减少。蔗糖预处理后,α2A-AR的螯合被部分抑制,但通过与高渗蔗糖和菲利普斯组合预处理,抑制网格蛋白包被和小窝囊泡的形成后,α2A-AR的螯合作用可进一步降低。在alpha2A-和alpha2B-AR的回收利用中也发现了差异。PC12细胞中最大激动剂诱导的螯合程度不直接取决于相对激动剂功效。通过高渗蔗糖预处理阻止网格蛋白包被的囊泡形成后,激动剂诱导的螯合α2B-AR明显减少。蔗糖预处理后,α2A-AR的螯合被部分抑制,但通过与高渗蔗糖和菲林酯联合预处理,抑制网格蛋白包被和小窝囊泡的形成后,α2A-AR的螯合作用可进一步降低。在alpha2A-和alpha2B-AR的回收利用中也发现了差异。PC12细胞中最大激动剂诱导的螯合程度不直接取决于相对激动剂功效。通过高渗蔗糖预处理阻止网格蛋白包被的囊泡的形成后,激动剂诱导的螯合α2B-AR明显减少。蔗糖预处理后,α2A-AR的螯合被部分抑制,但通过与高渗蔗糖和菲林酯联合预处理,抑制网格蛋白包被和小窝囊泡的形成后,α2A-AR的螯合作用可进一步降低。在alpha2A-和alpha2B-AR的回收利用中也发现了差异。PC12细胞中最大激动剂诱导的螯合程度不直接取决于相对激动剂功效。蔗糖预处理后,α2A-AR的螯合被部分抑制,但通过与高渗蔗糖和菲林酯联合预处理,抑制网格蛋白包被和小窝囊泡的形成后,α2A-AR的螯合作用可进一步降低。在alpha2A-和alpha2B-AR的回收利用中也发现了差异。PC12细胞中最大激动剂诱导的螯合程度不直接取决于相对激动剂功效。蔗糖预处理后,α2A-AR的螯合被部分抑制,但通过与高渗蔗糖和菲林酯联合预处理,抑制网格蛋白包被和小窝囊泡的形成后,α2A-AR的螯合作用可进一步降低。在alpha2A-和alpha2B-AR的回收利用中也发现了差异。PC12细胞中最大激动剂诱导的螯合程度不直接取决于相对激动剂功效。
更新日期:2019-11-01
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