线粒体侧向融合的分子机制

发布时间：2018-10-09 08:11

【摘要】：细胞中的线粒体处于经常运动、分裂与融合的活动状态。线粒体的不断融合与分裂确保了线粒体之间DNA的混合从而保证了线粒体代谢功能的正常运转。线粒体的融合是由一组dynamin类GTP酶所调节的。迄今为止的研究表明,这类分子基因的突变均会导致遗传性神经退行性疾病。亲管蛋白(syntabulin)在神经细胞轴突的囊泡和线粒体转运过程中扮演着重要角色。我们近来的研究发现,亲管蛋白也具有诱导线粒体融合的作用,其作用机制未清。本论文通过利用分子克隆、体外表达、基因沉默、分子和亚细胞水平动态观察以及免疫共沉降等手段对亲管蛋白诱导线粒体融合的机制进行了探讨。研究发现,亲管蛋白除了通过增加线粒体顶端接触外,还通过促进线粒体侧向间的相互作用和垂直接触来完成诱导线粒体在微管平台上融合并形成长管状的网络结构。亲管蛋白通过其螺旋盘卷区的相互作用将两线粒体沿其长轴并行排列或垂直接触并进一步诱导线粒体的侧向融合和分枝。当微管解聚后,线粒体管网状结构消失,短杆状线粒体由亲管蛋白组装成侧向排列的特殊结构,阶梯状亲管蛋白将多个线粒体联结成一个复合体,少数细胞中可见长管状线粒体由亲管蛋白黏着成双管结构。通过活细胞动态观察,我们证实了在天然表达亲管蛋白的原代神经细胞中,线粒体确实存在侧向融合和垂直融合。因此,亲管蛋白是以一种新的调节方式——即促进线粒体的侧向相互作用而导致线粒体的融合并通过微管这一支架完成管网状的线粒体结构。线粒体的融合过程一般需要GTP酶的参与,我们研究还发现的线粒体GTP酶Miro是亲管蛋白的结合蛋白,它可能也参与亲管蛋白诱导的线粒体融合过程。总之,本论文首次发现了Dynamin的GTP酶之外的,以亲管蛋白、微管骨架和Miro GTP酶为核心的一种新的线粒体融合调节体系。这将是线粒体融合方式的一个重要补充。
[Abstract]:The mitochondria in the cell are in a state of regular motion, division, and fusion. The continuous fusion and division of mitochondria ensure the mixing of DNA between mitochondria, thus ensuring the normal functioning of mitochondrial metabolic function. Mitochondrial fusion is regulated by a set of dynamin-like GTP-like enzymes. Studies so far have shown that mutations in these molecular genes can lead to hereditary neurodegenerative diseases. Tubular protein (syntabulin) plays an important role in the vesicle and mitochondrial transport of neuronal axons. Our recent studies have found that parenteral proteins can also induce mitochondrial fusion, the mechanism of which is unclear. In this paper, molecular cloning, in vitro expression, gene silencing, dynamic observation of molecular and subcellular level and immuno-co-deposition were used to investigate the mechanism of mitochondrial fusion induced by parenteral proteins. In addition to increasing the apical contact of mitochondria, parenteral proteins can induce mitochondrial fusion on microtubule platform and form long tubular network structure by promoting the interaction and vertical contact between mitochondria. The two mitochondria were arranged or contacted perpendicularly along their long axis by the interaction of capsid region and further induced the lateral fusion and branching of mitochondria. When the microtubule was depolymerized, the reticular structure of the mitochondria disappeared, and the short rod mitochondria were assembled into a special laterally arranged structure by the parent proteins. In a few cells, the long tubular mitochondria are formed by the attachment of the parent proteins into a double tubular structure. Through the dynamic observation of living cells, we have confirmed that in the primary nerve cells which naturally express the parent protein, the mitochondria do exist lateral fusion and vertical fusion. Therefore, parenteral protein is a new regulation mode, that is, to promote the side interaction of mitochondria, resulting in mitochondrial fusion and the completion of tubular reticular mitochondrial structure through microtubule scaffold. The process of mitochondrial fusion usually requires the participation of GTP enzyme. We also found that mitochondrial GTP enzyme Miro is a binding protein of the parent protein, and it may also participate in the process of mitochondrial fusion induced by the parent protein. In conclusion, we first found a new mitochondrial fusion regulatory system with the core of tubulin, microtubule skeleton and Miro GTP enzyme in addition to the GTP enzyme of Dynamin. This will be an important complement to the mitochondrial fusion approach.
【学位授予单位】：深圳大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：Q244

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