Establishing the role of the atypical kinase ADCK3 in mitochondrial metabolism

描述（由申请人提供）：线粒体是代谢和信号传导的中心，其功能对除少数真核细胞类型外的所有细胞类型都至关重要。这些细胞器的一般功能障碍与广泛的先天性代谢错误和越来越多的常见人类疾病有关。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的瓶颈。这一建议最初集中在一个这样的蛋白质，ADCK3，一个预测的激酶与辅酶Q的生物合成，线粒体电子传递链的组成部分的连接知之甚少。这种蛋白质的突变可引起小脑性共济失调，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非典型激酶家族的一部分——UbiB家族，迄今为止没有结构或功能特征的报道。该提案将建立UbiB家族原型成员的基本酶学特性，确定其直接内源性底物，并验证其通过改变局部磷脂环境来重塑线粒体内膜蛋白质基础结构的假设。利用该项目的研究人员提供的深度和广度的专业知识，提出的工作结合了多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和酵母，哺乳动物细胞培养和ADCK3缺乏症的小鼠敲除模型。随着ADCK3特性的深入，本文建立的方法和技术将随后应用于其他通常从酵母到后生动物保存的ADCK激酶。这些激酶包括人类线粒体中的四种激酶（ADCK1、2、4和5），它们现在与脂质代谢和特定癌症相关，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，除了将产生关于ADCK3特定功能的直接见解外，这项工作还为对具有日益重要的生物医学意义的独特线粒体激酶家族进行广泛分析奠定了基础。

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.