In vitro studies on the role of the peripheral-type benzodiazepine receptor in steroidogenesis
In vitro studies on the role of the peripheral-type benzodiazepine receptor in steroidogenesis
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DOI：
10.1016/s0960-0760(99)00056-4
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发表时间：
1999-04-01
影响因子：
4.1
通讯作者：
Papadopoulos, V
中科院分区：
文献类型：
--
作者：
Culty, M;Li, H;Papadopoulos, V
利用分离的细胞、线粒体和线粒体亚组分进行的体外研究表明，在类固醇合成细胞中，外周型苯二氮卓受体(PBR)是一种外膜蛋白，优先位于外膜/内膜接触部位，参与调节胆固醇从外膜到内膜的运输，这是类固醇生物合成的决定步骤。线粒体每个配体的结合特征和形态对激素处理很敏感，这表明PER在激素介导的类固醇合成调节中发挥作用。在体外，靶向干扰LeyDig细胞中的PER基因导致胆固醇转运到线粒体和类固醇形成的停止；将PER基因导入突变细胞，挽救了类固醇的生成，证明了PER在胆固醇转运中的必备作用。PER的分子模拟表明，它可能是胆固醇的通道。这一假设在一个没有PER和胆固醇的细菌系统中得到了验证。在PER表达后，这些细胞对胆固醇的摄取和运输被诱导。氨基酸缺失、定点突变研究和突变体PBRs的表达表明，胆固醇识别/相互作用氨基酸共有序列的受体存在于细胞质的羧基末端。这一氨基酸序列可能有助于将来自细胞内部位的胆固醇重新招募到线粒体。(C)1999爱思唯尔科学有限公司。保留所有权利。
In vitro studies using isolated cells, mitochondria and submitochondrial fractions demonstrated that in steroid synthesizing cells, the peripheral-type benzodiazepine receptor (PBR) is an outer mitochondrial membrane protein, preferentially located in the outer/inner membrane contact sites, involved in the regulation of cholesterol transport from the outer to the inner mitochondrial membrane, the rate-determining step in steroid biosynthesis. Mitochondrial PER ligand binding characteristics and topography are sensitive to hormone treatment suggesting a role of PER in the regulation of hormone-mediated steroidogenesis. Targeted disruption of the PER gene in Leydig cells in vitro resulted in the arrest of cholesterol transport into mitochondria and steroid formation; transfection of the mutant cells with a PER cDNA rescued steroidogenesis demonstrating an obligatory role for PER in cholesterol transport. Molecular modeling of PER suggested that it might function as a channel for cholesterol. This hypothesis was tested in a bacterial system devoid of PER and cholesterol. Cholesterol uptake and transport by these cells was induced upon PER expression. Amino acid deletion followed by site-directed mutagenesis studies and expression of mutant PBRs demonstrated the presence in the cytoplasmic carboxy-terminus of the receptor of a cholesterol recognition/interaction amino acid consensus sequence. This amino acid sequence may help for recruiting the cholesterol coming from intracellular sites to the mitochondria. (C) 1999 Elsevier Science Ltd. All rights reserved.