Biogenesis of Respiratory Chain Complex I and Analysis of Assembly Defects in Patients with Mitochondrial Disease

线粒体呼吸链的复合体I是蛋白质亚基的大集合，参与细胞能量的主要产生。复合体I存在于称为线粒体的细胞内。复合体I的困境是，为了建立它，它需要38种不同的蛋白质，这些蛋白质在细胞的一个地方制造，被导入线粒体，然后以某种方式与线粒体组成的其他7个亚基连接在一起。这显然是一个复杂的过程，我们对其组装是如何实现的知之甚少。然而，我们知道，在组装复杂的错误我确实会发生。在澳大利亚，每年出生的大约50名儿童患有遗传性线粒体能量生成障碍。最严重的疾病会导致婴儿死亡，而后来出现的其他疾病会导致一系列退行性疾病，特别是影响大脑、肌肉和心脏。这些患者最常见的缺陷是复合体I活性的丧失。有趣的是，似乎在大多数情况下，这种缺陷并不是由于一个或多个复合体I亚单位的突变造成的，所以我们认为这种缺陷是由参与构建复合体I的辅助蛋白引起的。本建议的目的是研究复合体I是如何组装的，并鉴定和表征辅助蛋白。我们还将通过研究患者的皮肤成纤维细胞来分析组装缺陷。这项工作不仅将帮助我们理解蛋白质复合体是如何构建的，而且还将有助于我们理解它们组装中的缺陷如何导致疾病。这不仅将为受影响个人的家庭提供信息，而且可能有助于未来对线粒体疾病的诊断和预防。

Complex I of the mitochondrial respiratory chain is a large assembly of protein subunits that is involved in the main production of cellular energy. Complex I is found in intracellular compartments termed mitochondria. The predicament for Complex I is that in order for it to be built, it requires 38 different proteins that are made in one place in the cell to be imported into mitochondria and then somehow joined together with the 7 other subunits that are made by mitochondria. This is clearly a complicated procedure and we have little information on how its assembly is achieved. We do know however that mistakes in the assembly of Complex I do happen. In Australia, about 50 children born each year have inherited disorders of mitochondrial energy generation. The most severe disorders cause infant death, while others present later causing a range of degenerative diseases, particularly affecting brain, muscle and heart. The most common defect in these patients is a loss in the activity of Complex I. Interestingly it seems that in most cases, the defect is not due to a mutation in one or more of the Complex I subunits and so we believe that such defects arise form accessory proteins that are involved in the construction of Complex I. The aim of this proposal is to investigate how Complex I is assembled and to identify and characterise accessory proteins. We will also analyse assembly defects by studying skin fibroblasts from patients. This work will aid in our understanding of not only how protein complexes are built, but how defects in their assembly can cause disease. This will not only be informative to families of affected individuals but may aid in future diagnosis and prevention of mitochondrial disease.