Establishing the role of the atypical kinase ADCK3 in mitochondrial metabolism

描述(申请人提供)：线粒体是新陈代谢和信号传递的中心，其功能对除少数真核细胞类型之外的所有细胞类型都是必不可少的。这些细胞器的普遍功能障碍与一系列先天代谢错误有关，也与越来越多的人类常见疾病有关。阐明这些疾病相关蛋白的生化功能已成为了解线粒体病理生理学的瓶颈。这一建议最初关注的是一种名为ADCK3的蛋白，它是一种预测的激酶，与辅酶Q的生物合成之间的联系鲜为人知，辅酶Q是线粒体电子传输链的组成部分。这种蛋白的突变可能导致一种形式的小脑性共济失调，这是众多线粒体呼吸链疾病之一。更广泛地说，ADCK3是一个庞大而古老的预测非典型激酶家族的一部分-UbiB家族-到目前为止还没有结构或功能特征的报道。这一提议将建立UbiB家族原型成员的基本酶学性质，鉴定其直接内源底物(S)，并验证其功能是通过改变局部磷脂环境来重塑线粒体内膜的蛋白质基础结构的假说。利用通过该计划项目的研究人员提供的专业知识的深度和广度，拟议的工作结合了各种工具来实现这些目标，包括：一个强大的、高质量精度的脂质组学平台以及ADCK3缺乏症的酵母、哺乳动物细胞培养和小鼠基因敲除模型。随着ADCK3表征的进展，这里建立的方法和技术将随后应用于其他ADCK激酶，这些酶通常是从酵母到后生动物保守的。这些激酶包括人类线粒体中的四个(ADCK1、2、4和5)，它们现在既与脂代谢有关，也与特定癌症有关，包括多形性胶质母细胞瘤(GBM)和雌激素受体阳性(ER)乳腺肿瘤。因此，除了关于ADCK3特定功能的直接见解外，这项工作还为广泛分析具有越来越重要的生物医学意义的独特的线粒体激酶家族奠定了基础。

DESCRIPTION (provided by applicant): Mitochondria are centers of metabolism and signaling whose function is essential to all but a few eukaryotic cell types. General dysfunction of these organelles is implicated in a wide range of inborn errors of metabolism, and in an increasing number of common human diseases. Elucidation of the biochemical functions of these disease-related proteins has become a bottleneck in understanding mitochondrial pathophysiology. This proposal initially focuses on one such protein, ADCK3, a predicted kinase with a poorly understood connection to the biosynthesis of coenzyme Q, an integral part of the mitochondrial electron transport chain. Mutations in this protein can cause a form of cerebellar ataxia, one of numerous mitochondrial respiratory chain disorders. More broadly, ADCK3 is part of a large and ancient family of predicted atypical kinases-the UbiB family-that has no structural or functional characterization reported to date. This proposal will establish the fundamental enzymatic properties of this archetypal member of the UbiB family, identify its direct endogenous substrate(s), and test the hypothesis that it functions to remodel the protein infrastructure of th inner mitochondrial membrane through alterations in the local phospholipid environment. Leveraging the depth and breadth of expertise available through the investigators of this program project, the proposed work incorporates a diverse range of tools to address these goals, including: a robust, high mass-accuracy lipidomics platform and yeast, mammalian cell culture and mouse knockout models of ADCK3 deficiency. As the characterization of ADCK3 progresses, the approaches and techniques established here will subsequently be applied to the other ADCK kinases that are generally conserved from yeast through metazoans. These kinases include four in human mitochondria (ADCK1, 2, 4 and 5), which have now been associated both with lipid metabolism and with specific cancers, including glioblastoma multiforme (GBM) and estrogen receptor-positive (ER+) breast tumors. Thus, in addition to the direct insights that will be generate regarding the specific function of ADCK3, this work sets the stage for an extensive analysis of a unique mitochondrial kinase family of mounting biomedical importance.