Dual Role of the β2-Adrenergic Receptor C Terminus for the Binding of β-Arrestin and Receptor Internalization
Dual Role of the β2-Adrenergic Receptor C Terminus for the Binding of β-Arrestin and Receptor Internalization
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DOI：
10.1074/jbc.m806086200
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发表时间：
2008-11-14
影响因子：
4.8
通讯作者：
Lohse, Martin J.
中科院分区：
文献类型：
--
作者：
Krasel, Cornelius;Zabel, Ulrike;Lohse, Martin J.
β(2)-肾上腺素能受体和其他 G 蛋白偶联受体的同源脱敏是一个两步过程。 G 蛋白偶联受体激酶将激动剂占据的受体磷酸化后，它们与 β-抑制蛋白结合，从而引发受体脱敏和内化。由于尚不清楚β-抑制蛋白能识别受体的哪些区域，因此我们研究了β-抑制蛋白的相互作用以及一组人β(2)-肾上腺素能受体突变体的内化。荧光共振能量转移 (FRET)、β-arrestin2 易位至质膜和受体内化表明，残基 355 和 364 之间的四个丝氨酸/苏氨酸残基的突变导致激动剂诱导的受体-β-arrestin2 相互作用的丧失。残基 381 远端的所有七个丝氨酸/苏氨酸残基的突变不影响激动剂诱导的受体内化和 β-arrestin2 易位。残基 381 远端截短的 β(2)-肾上腺素能受体与 β-arrestin2 正常相互作用，但其以激动剂依赖性方式内化的能力受到损害。当仅删除 C 末端的最后 8 个残基时，观察到类似的内化损害。我们的实验表明，残基 381 远端的 C 末端不影响受体和 β-arrestin 之间的初始相互作用，但其最后 8 个氨基酸与 β-arrestin2 协同促进受体内化。
Homologous desensitization of beta(2)-adrenergic and other G-protein-coupled receptors is a two-step process. After phosphorylation of agonist-occupied receptors by G-protein-coupled receptor kinases, they bind beta-arrestins, which triggers desensitization and internalization of the receptors. Because it is not known which regions of the receptor are recognized by beta-arrestins, we have investigated beta-arrestin interaction and internalization of a set of mutants of the human beta(2)-adrenergic receptor. Mutation of the four serine/threonine residues between residues 355 and 364 led to the loss of agonist-induced receptor-beta-arrestin2 interaction as revealed by fluorescence resonance energy transfer (FRET), translocation of beta-arrestin2 to the plasma membrane, and receptor internalization. Mutation of all seven serine/threonine residues distal to residue 381 did not affect agonist-induced receptor internalization and beta-arrestin2 translocation. A beta(2)-adrenergic receptor truncated distal to residue 381 interacted normally with beta-arrestin2, whereas its ability to internalize in an agonist-dependent manner was compromised. A similar impairment of internalization was observed when only the last eight residues of the C terminus were deleted. Our experiments show that the C terminus distal to residue 381 does not affect the initial interaction between receptor and beta-arrestin, but its last eight amino acids facilitate receptor internalization in concert with beta-arrestin2.