FUNCTIONAL DESENSITIZATION OF THE ISOLATED BETA-ADRENERGIC-RECEPTOR BY THE BETA-ADRENERGIC-RECEPTOR KINASE - POTENTIAL ROLE OF AN ANALOG OF THE RETINAL PROTEIN ARRESTIN (48-KDA PROTEIN)
FUNCTIONAL DESENSITIZATION OF THE ISOLATED BETA-ADRENERGIC-RECEPTOR BY THE BETA-ADRENERGIC-RECEPTOR KINASE - POTENTIAL ROLE OF AN ANALOG OF THE RETINAL PROTEIN ARRESTIN (48-KDA PROTEIN)
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DOI：
10.1073/pnas.84.24.8879
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发表时间：
1987-12-01
影响因子：
11.1
通讯作者：
LEFKOWITZ, RJ
中科院分区：
文献类型：
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作者：
BENOVIC, JL;KUHN, H;LEFKOWITZ, RJ
β-肾上腺素能受体激酶是一种可能类似于视紫红质激酶的酶，其使β-肾上腺素能受体激酶多重磷酸化。肾上腺素能受体只有在被刺激性激动剂占据时才起作用。由于这种激酶可能在介导同源或激动剂特异性脱敏过程中发挥重要作用，我们研究了激酶受体磷酸化的功能后果以及与视紫红质激酶作用机制的可能类比。评价在磷脂囊泡中重构的纯仓鼠肺β 2-肾上腺素能受体介导共重构的刺激性鸟嘌呤核苷酸结合调节蛋白的GT3活性的激动剂促进的刺激的能力。当受体被部分磷酸化时（apprxeq. 350倍）纯化的β-肾上腺素能受体激酶，多达80%的失活，其功能活性的观察。然而，使用更高度纯化的酶制剂导致磷酸化修饰受体的能力显著降低，使得纯酶制剂（约20，000倍纯化）仅引起最小的（约20，000倍纯化）。16 .+-. 7%）失活。加入纯的视网膜抑制蛋白（48-kDa蛋白或S抗原），其参与增强视紫红质激酶对视紫红质磷酸化的失活作用，导致β-视紫红质的功能作用的部分恢复。肾上腺素能受体激酶促进的磷酸化（41 . ±. 3%失活）。这些结果表明类似于视网膜抑制蛋白的蛋白质可能存在于其他组织中并与β-肾上腺素能受体激酶调节腺苷酸环化酶偶联受体的活性。
The .beta.-adrenergic receptor kinase is an enzyme, possibly analogous to rhodopsin kinase, that multiple phosphorylates the .beta.-adrenergic receptor only when it is occupied by stimulatory agonists. Since this kinase may play an important role in mediating the process of homologous, or agonist-specific, desensitization, we investigated the functional consequences of receptor phosphorylation by the kinase and possible analogies with the mechanism of action of rhodopsin kinase. Pure hamster lung .beta.2-adrenergic receptor, reconstituted in phospholipid vesicles, was assessed for its ability to mediate agonist-promoted stimulation of the GTPase activity of coreconstituted stimulatory guanine nucleotide-binding regulatory protein. When the receptor was phosphorylated by partially (.apprxeq. 350-fold) purified preparations of .beta.-adrenergic receptor kinase, as much as 80% inactivation of its functional activity was observed. However, the use of more highly purified enzyme preparations led to a dramatic decrease in the ability of phosphorylation to inactivate the receptor such that pure enzyme preparations (.apprxeq. 20,000-fold purified) caused only minimal (.apprxeq. 16 .+-. 7%) inactivation. Addition of pure retinal arrestin (48-kDa protein or S antigen), which is involved in enhancing the inactivating effect of rhodopsin phosphorylation by rhodopsin kinase, led to partial restoration of the functional effect of .beta.-adrenergic receptor kinase-promoted phosphorylation (41 .+-. 3% inactivation). These results suggest the possibility that a protein analogous to retinal arrestin may exist in other tissues and function in concert with .beta.-adrenergic receptor kinase to regulate the activity of adenylate cyclase-coupled receptors.