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PINK1蛋白在线粒体外膜上的定位机制研究

The Mechanism of PINK1 Localization on the Outer Membrane of Mitochondria

  • 摘要: 目的 研究帕金森氏病相关蛋白PINK1在线粒体外膜上定位的具体机制。 方法 以体外培养的HEK293T细胞转染表达不同蛋白的真核表达质粒,然后加入DMSO作为对照或者加入线粒体解偶联剂CCCP,以Western印迹和免疫共沉淀技术来检测蛋白的表达和相互作用的变化。 结果 全长的PINK1在CCCP作用下和线粒体上的Tom40的相互作用能力是DMSO对照的20倍以上,而去掉线粒体定位序列(MTS)和跨膜序列(TM)的PINK1以及其它线粒体外膜蛋白在CCCP作用下没有这样的相互作用。当CCCP去掉后,PINK1全长和Tom40的相互作用迅速减弱。去掉或突变掉TM序列的PINK1和Tom40不论在CCCP是否存在的情况下,均有相互作用。 结论 在受损线粒体外膜积累的PINK1只是卡在外膜蛋白转运通道上,并没有真正转运到外膜上。而当线粒体的跨膜电位恢复时,它会继续向内转运。

     

    Abstract: Objective To study the specific mechanism of PTEM-induced putative kinase 1(PINK1) located to the outer membrane of damaged mitochondria. Methods Cultured HEK293T cells were transfected with plasmids expressing different proteins, following with DMSO or CCCP treatment. Western blot and coimmuoprecipitation were used to detect the expression and interaction of proteins. Results Full length PINK1, but not its mitochondria targeting sequence (MTS) & trans-membrane (TM) deleted forms or other outer mitochondria outer membrane proteins, could interact with Tom40 upon CCCP treatment and the interaction ability was more than 20 times stronger than that of DMSO control. When the added CCCP is washed out, the interaction between full length PINK1 and Tom40 declined rapidly. PINK1 with removed or mutated TM can interact with Tom40 even in the absence of CCCP. Conclusion The accumulated PINK1 on the outer membrane of damaged mitochondria is just stuck on the TOM complex instead of integrated into the lipid bilayer.

     

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