Agonist-dependent desensitization of the κ opioid receptor by G protein receptor kinase and β-arrestin
Agonist-dependent desensitization of the κ opioid receptor by G protein receptor kinase and β-arrestin
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DOI：
10.1074/jbc.274.34.23802
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发表时间：
1999-08-20
影响因子：
4.8
通讯作者：
Chavkin, C
中科院分区：
文献类型：
--
作者：
Appleyard, SM;Celver, J;Chavkin, C
我们利用非洲爪蟾卵母细胞表达系统研究了G蛋白受体激酶（GRKs）对大鼠κ阿片受体（KOR）功能的调节。在共表达KOR与Kir3.1和Kir3.4的卵母细胞中，κ激动剂可增加G蛋白激活的内向整流钾通道的电导。在没有添加GRK和β-抑制蛋白2的情况下，κ激动剂诱导的钾电流的脱敏是适度的。GRK 3或GRK 5沿着与β-arrestin 2的共表达显著增加了脱敏率，而单独添加β-arrestin 2、GRK 3或GRK 5对KOR脱敏率没有影响。脱敏是同源的，因为共表达的δ阿片受体诱发的反应不受KOR脱敏的影响。GRK 3/β-抑制蛋白2依赖性脱敏的速率通过截短C-末端26个氨基酸KOR（Q355 Delta）而降低。相反，在第三胞内环[KOR（S255 A，S260 A，S262 A）]内Ala取代Ser并不降低脱敏率。在C端区域内，KOR（S369 A）取代显著减弱脱敏，而KOR（T363 A）和KOR（S356 A，T357 A）点突变则不降低脱敏率。这些结果表明，GRK 3或GRK 5和β-arrestin 2的共表达通过需要rKOR的丝氨酸369的磷酸化的机制产生同源的激动剂诱导的κ阿片受体的脱敏。
We used the Xenopus oocyte expression system to examine the regulation of rat kappa opioid receptor (KOR) function by G protein receptor kinases (GRKs), kappa agonists increased the conductance of G protein-activated inwardly rectifying potassium channels in oocytes coexpressing KOR with Kir3.1 and Kir3.4. In the absence of added GRK and beta-arrestin 2, desensitization of the kappa agonist-induced potassium current was modest. Co expression of either GRK3 or GRK5 along with beta-arrestin 2 significantly increased the rate of desensitization, whereas addition of either beta-arrestin 2, GRK3, or GRK5 alone had no effect on the KOR desensitization rate, The desensitization was homologous as co-expressed delta opioid receptor-evoked responses were not affected by KOR desensitization. The rate of GRK3/beta-arrestin 2-dependent desensitization was reduced by truncation of the C-terminal 26 amino acids, KOR(Q355 Delta). In contrast, substitution of Ala for Ser within the third intracellular loop [KOR(S255A,S260A,S262A)] did not reduce the desensitization rate, Within the C-terminal region, KOR(S369A) substitution significantly attenuated desensitization, whereas the KOR(T363A) and KOR(S356A,T357A) point mutations did not. These results suggest that co-expression of GRK3 or GRK5 and beta-arrestin 2 produced homologous, agonist-induced desensitization of the kappa opioid receptor by a mechanism requiring the phosphorylation of the serine 369 of rKOR.