Binding of aryl hydrocarbon receptor (AhR) to AhR-interacting protein - The role of hsp90
Binding of aryl hydrocarbon receptor (AhR) to AhR-interacting protein - The role of hsp90
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DOI：
10.1074/jbc.m004236200
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发表时间：
2000-11-17
影响因子：
4.8
通讯作者：
Poland, A
中科院分区：
文献类型：
--
作者：
Bell, DR;Poland, A
芳香烃受体（AhR）已被证明与亲免素样分子（称为AhR相互作用蛋白（AIP））相互作用，并增强AhR功能。我们在这里表明，AIP协会与AhR同源物从小鼠和鱼类，可以结合配体，如二恶英，但nonligand结合同源物从秀丽隐杆线虫或果蝇不结合AIP。然而，AhR的最小配体结合结构域不能结合AIP。AIP与网织红细胞裂解物中AhR的结合显示了热休克蛋白90依赖性过程的几个特征，包括对格尔德霉素和温度的敏感性以及对ATP或不可水解类似物的需求。纯化的AIP与hsp 90的C末端结合，并且AIP的三肽重复序列中的保守碱性残基（K266 A，类似于蛋白磷酸酶5中的K97 A）的突变废除与hsp 90的结合。AIP中K266 A的突变使与AhR的结合减少75-80%;该复合物的格尔德霉素敏感性表明AhR稳定AIP-hsp 90-AhR复合物。AIP的α-螺旋C末端在三肽重复结构域之外，如C末端5个氨基酸的缺失或丙氨酸扫描诱变所示，它是与AhR结合所绝对需要的，但它不是AIP与hsp 90结合所必需的。数据支持以下模型：1）AIP结合hsp 90和AhR; 2）AhR-AIP结合需要hsp 90; 3）AhR与AIP的结合稳定AIP-hsp 90-AhR复合物。
The aryl hydrocarbon receptor (AhR) has been shown to interact with an immunophilin-like molecule known as AhR-interacting protein (AIP) and to enhance AhR function. We show here that AIP associates with AhR homologues from mouse and fish, which can bind ligands such as dioxin, but nonligand binding homologues from Caenorhabditis elegans or Drosophila do not bind to AIP. However, a minimal ligand-binding domain of the AhR is incapable of binding AIP. The binding of AIP to AhR in reticulocyte lysate shows several of the characteristics of an hsp90-dependent process, including sensitivity to geldanamycin and temperature and a requirement for ATP or nonhydrolyzable analogues. Purified AIP binds to the C terminus of hsp90, and mutation of a conserved basic residue in the tetratricopeptide repeats of AIP (K266A, analogous to K97A in protein phosphatase 5) abolishes binding to hsp90. Mutation of K266A in AIP reduces binding to AhR by 75-80%; the geldanamycin sensitivity of this complex shows that AhR stabilizes the AIP-hsp90-AhR complex. The alpha -helical C terminus of AIP, which is outside the tetratricopeptide repeat domain, is absolutely required for binding to AhR as shown by deletions of the C-terminal 5 amino acids or alanine-scanning mutagenesis, but it is not required for binding of AIP to hsp90. The data support a model where 1) AIP binds to both hsp90 and AhR; 2) hsp90 is required for AhR-AIP binding; and 3) the binding of AhR to AIP stabilizes the AIP-hsp90-AhR complex.