CYTOCHROME C OXIDASE IN HEALTH AND DISEASE

细胞色素c氧化酶（考克斯）缺乏是线粒体神经肌病最常见的病因 人类患有这些疾病的患者呈现异质性临床表型，包括Leigh 综合征、肌无力和脑肌病。 对于阐明这组疾病的分子基础至关重要。的主要目标 建议的研究是使用酿酒酵母作为模型来研究COX组装 在野生型细胞和进化保守的组装因子突变的细胞中。几个具体 目标将被追求。1)我们最近报道了Shylp，humanSurMp的酵母同源物， 导致大多数利氏综合征，催化考克斯组装中间体的形成 涉及Coxlp，一种考克斯的经尿道编码的催化亚基。Shylp在表达中的作用 将研究Coxlp。2)最近的证据表明，该中间体调节Cox1 p表达， 该过程涉及其它考克斯代谢因子，如Mss 51 p和Cox 14 p。 将研究这些蛋白质调节考克斯表达的机制。适当标记的Mss51p和Cox14p将 从过表达的酵母细胞中纯化。纯化蛋白的可用性将允许假设 直接测试他们的活动。3)参与调节Coxlp合成的蛋白质 考克斯组装体可能与它们短暂或永久地相互作用，使它们发挥功能。的 这些相互作用的性质将被表征。总之，酵母系统将被探索作为一种手段， 破译复杂的膜酶组装的一般原理， 来自两个空间上分离的遗传来源的亚基多肽。酵母范例将是 利用生物化学和遗传学手段，以全面了解Shylp的功能， 因此Surflp也是如此，并阐明人类考克斯缺陷的分子基础。

Cytochrome c oxidase (COX) deficiency is the most frequent cause of mitochondrial neuromyopathiesin humans. Patients afflicted with these diseases present heterogeneous clinical phenotypes, including Leigh syndrome, muscle weakness and encephalomyopathy.A complete understanding of COX biogenesis is essential for elucidating the molecular basis underlying this group of diseases. The main objective of the proposed research is to use the yeast Saccharomycescerevisiae as a model to investigate COXassembly in wild type cells and in cells with mutations in evolutionary conservedassembly factors. Several specific aims will be pursued. 1) We have recently reported that Shylp, the yeast homologue of humanSurMp, responsible for most cases of Leigh's syndrome,catalyzes the formation of a COX assembly intermediate involving Coxlp, a mitochondrially encoded catalytic subunit of COX. The role of Shylp in expression of Coxlp will be studied. 2) More recent evidence indicates that this intermediate regulates Cox1 pexpression in a process involving other COX metabolism factors, such as Mss51p and Cox14p.The mechanisms by which these proteins regulate COX expression will be studied. Appropriately tagged Mss51p and Cox14p will be purified from over-expressing yeast cells. The availability of purified proteins will permit hypotheses concerning their activities to be tested directly. 3) The proteins involved in regulation of Coxlp synthesis by COX assembly are likely to interact transiently or permanently amongthem to perform their functions. The nature of these interactions will be characterized. In summary,the yeast system will be explored as a means of deciphering the general principles operating in the assembly of a complex membrane enzyme composed of subunit polypeptides derived from two spatially separated genetic sources. The yeast paradigm will be exploited by biochemical and genetic meansto gain a complete understanding of the function of Shylp and therefore of Surflp as well, and to clarifythe molecular basis of human COX deficiencies.