mitoNEET在细胞铁硫簇转运中的作用及调节机制研究

铁硫簇是在生命活动中起重要作用的氧化还原中心，它在线粒体合成后被运输到细胞质或其它细胞器参与铁硫蛋白的组装，其转运机制尚不清楚。mitoNEET是定位于线粒体外膜且含1个不稳定铁硫簇的低分子量蛋白，它能特异地结合抗2型糖尿病药物吡格列酮。我们前期工作和已有的文献表明，mitoNEET与IscU（铁硫簇合成的支架蛋白）具有相似的结构，且均能结合铁硫簇和锌。推测mitoNEET可能参与铁硫簇从线粒体向细胞质的转运，此功能受锌和吡格列酮调节。为此，本项目拟展开如下研究：1）验证mitoNEET在细胞中铁硫簇的转运作用；2）确定锌在mitoNEET中的结合位点及对铁硫簇结合的相互竞争关系；3）探究锌和吡格列酮对mitoNEET中铁硫簇合成与转运的调节作用。因此，本研究能揭示mitoNEET在细胞中铁硫簇转运中的作用，同时为2型糖尿病新药研发提供重要的药靶信息。

As a group of the most ancient redox centers in living organisms, iron-sulfur clusters are required for many important physiological processes. In eukaryotic cells, iron-sulfur clusters are mainly assembled in mitochondria, and transported into cytoplasm or other organelles for maturation of iron-sulfur proteins. However, the mechanism underlying the iron-sulfur cluster assembly in proteins is still poorly understood. Human mitoNEET, a novel target of type 2 diabetes drug pioglitazone, is an integral outer mitochondrial membrane protein that contains a labile [2Fe-2S] cluster. Deletion of mitoNEET in mice results in a reduced oxidative phosphorylation capacity in mitochondria. In this application, we propose to test a hypothesis that mitoNEET is involved in transporting iron-sulfur clusters from mitochondria to cytoplasm and that such function of mitoNEET could be regulated by zinc ion and type 2 diabetes drug pioglitazone. Specifically, we will investigate: 1) the role of mitoNEET in the iron-sulfur cluster assembly in cytoplasm; 2) the competition of zinc ion for the iron-sulfur cluster binding site in mitoNEET; and 3) the modulation of the iron-sulfur cluster assembly in mitoNEET and subsequent delivery by type 2 diabetes drug pioglitazone. The results are expected to reveal the specific role of mitoNEET in the iron-sulfur cluster assembly in cytoplasm and to provide fundamental information for developing new therapetic approaches for type 2 diabetes.