Peripheral-type benzodiazepine receptor function in cholesterol transport. Identification of a putative cholesterol recognition/interaction amino acid sequence and consensus patterns
Peripheral-type benzodiazepine receptor function in cholesterol transport. Identification of a putative cholesterol recognition/interaction amino acid sequence and consensus patterns
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DOI：
10.1210/en.139.12.4991
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发表时间：
1998-12-01
期刊：
影响因子：
4.8
通讯作者：
Papadopoulos, V
中科院分区：
文献类型：
--
作者：
Li, H;Papadopoulos, V
在类固醇合成细胞中，如MA-10小鼠肿瘤Leydig细胞，外周型苯二氮卓受体（PBR）是一种线粒体外膜蛋白，参与调节胆固醇从线粒体外膜转运到线粒体内膜，这是类固醇生物合成中的速率决定步骤。在大肠杆菌DE 3细胞中表达PER，该细胞没有PER，没有胆固醇，酸不产生类固醇，诱导以时间依赖性，温度敏感性和能量独立性的方式摄取胆固醇的能力。这些细胞没有接受其他测试的类固醇。将高亲和力PER配体PK 11195添加到从用PER转染的细胞获得的负载胆固醇的膜中，导致所摄取的胆固醇的释放。突变PBRs在DE 3细胞中的表达表明，胞质羧基末端的缺失显著降低了PER的胆固醇摄取功能，尽管它保留了结合PK 11195的全部能力。PER羧基末端区域的定点诱变表明，表达突变PER蛋白PBR（Y153 S）和PBR（R156 L）的细菌不积累胆固醇，表明氨基酸Y153和R156参与受体与胆固醇的相互作用。考虑到这些结果，我们假设存在常见的胆固醇识别/相互作用氨基酸共有模式（-L/V-（X）（1-5）-Y-（X）（1-5）-R/K-）。事实上，我们在所有与胆固醇相互作用的蛋白质中发现了这种氨基酸一致模式。总之，这些数据表明PER的表达赋予了在配体活化时摄取和释放胆固醇的能力。考虑到这种蛋白质的广泛存在及其组织和细胞特异性亚细胞定位，这些结果表明PER在细胞内胆固醇转运和区室化中具有更普遍的作用。
In steroid-synthesizing cells, like the MA-10 mouse tumor Leydig cells, the peripheral-type benzodiazepine receptor (PBR) is an outer mitochondrial membrane protein involved in the regulation of cholesterol transport from the outer to the inner mitochondrial membrane, the rate-determining step in steroid biosynthesis. Expression of PER in Escherichia coli DE3 cells, which have no PER, no cholesterol, acid do not make steroids, induced the ability to take up cholesterol in a time-dependent, temperature-sensitive, and energy-independent manner. These cells took up no other steroids tested. Addition of the high affinity PER ligand PK 11195 to cholesterol-loaded membranes, obtained from cells transfected with PER, resulted in the release of the uptaken cholesterol. Expression in DE3 cells of mutant PBRs demonstrated that deletions in the cytoplasmic carboxy-terminus dramatically reduced the cholesterol uptake function of PER, although it retained full capacity to bind PK 11195. Site-directed mutagenesis in the carboxy-terminal region of PER demonstrated that bacteria expressing the mutant PER proteins PBR(Y153S) and PBR(R156L) do not accumulate cholesterol, suggesting that amino acids Y153 and R156 are involved in the interaction of the receptor with cholesterol. Considering these results, we postulate the existence of a common cholesterol recognition/interaction amino acid consensus pattern (-L/V-(X)(1-5)-Y-(X)(1-5)-R/K-). Indeed, we found this amino acid consensus pattern in all proteins shown to interact with cholesterol. In conclusion, these data suggest that the expression of PER confers the ability to take up and release, upon ligand activation, cholesterol. Considering the widespread occurrence of this protein and its tissue and cell specific subcellular localization, these results suggest a more general role of PER in intracellular cholesterol transport and compartmentalization.