Regulation of mitochondrial metabolism by lysine acylation

项目摘要 脂肪酸氧化（FAO）是心脏、肌肉和肝脏等中的关键能量产生途径。 机关FAO途径基因的先天性缺陷与这些器官的功能障碍有关， 死亡率。此外，粮农组织的中断也见于多基因疾病，如肥胖、糖尿病和 癌随着血液代谢物质谱分析的进展，FAO缺陷可以很容易地被发现。 诊断。然而，尽管进行了30年的深入研究，但在人类中调节FAO的治疗选择仍然存在。 患者仍然有限和无效。关于粮农组织酶的监管和 粮农组织途径在线粒体能量代谢的更大景观中的功能组织 限制了新疗法的发展在上一个资助期内，我们设立了 可逆的赖氨酸翻译后修饰（乙酰化，琥珀酰化）作为FAO的调节剂。我们展示 去酰化目标赖氨酸并将其恢复到天然状态的sirtuin酶是重要的参与者， 最大限度地发挥粮农组织途径的作用。在目前的建议中，我们假设赖氨酸酰化 调节FAO酶的活性，定位于线粒体内膜，以及更高级的 FAO蛋白质和呼吸链之间的代谢复合物。在具体目标1中，我们将采用 我们在前一个资助期开创的体外方法，以确定沉默调节蛋白靶向的赖氨酸在 膜相关FAO酶肉毒碱棕榈酰转移酶-2（CPT 2），线粒体三功能 蛋白质（TFP）和酰基辅酶A脱氢酶-9（ACAD9）。我们将进行诱变研究，以确定 每个沉默调节蛋白靶向赖氨酸残基的功能作用。在具体目标2中，我们将研究物理 以及三种线粒体sirtuins（SIRT3，SIRT4和SIRT5）与内 线粒体膜我们假设sirtuins警察线粒体内膜，以 促进高级代谢复合物的组装和运作，如粮农组织之间形成的那些 和电子传递链。最后，具体目标3将评估赖氨酸酰化对这些 使用小鼠模型和体外组装的蛋白质复合物的组合的高阶复合物。 了解sirtuins在调节FAO和代谢超复合物中的作用将为 致力于开发新的治疗方法，以操纵患有先天性缺陷的人类患者的线粒体功能 以及患有慢性疾病如肥胖、糖尿病和癌症的人。

PROJECT ABSTRACT Fatty acid oxidation (FAO) is a critical energy producing pathway in heart, muscle, and liver, among other organs. Inborn errors in genes of the FAO pathway are associated with dysfunction in these organs and a high rate of mortality. Additionally, disruptions in FAO are seen in polygenic diseases such as obesity, diabetes, and cancer. With advances in mass spectrometry profiling of blood metabolites, FAO defects can be readily diagnosed. However, despite 30 years of intensive study, treatment options for modulating FAO in human patients remain limited and ineffective. Knowledge gaps regarding the regulation of FAO enzymes and the functional organization of the FAO pathway within the greater landscape of mitochondrial energy metabolism have limited the development of new therapies. In the previous funding period of this grant, we established reversible lysine post-translational modifications (acetylation, succinylation) as regulators of FAO. We showed that sirtuin enzymes, which deacylate target lysines and restore them to the native state, are important players in maximizing function of the FAO pathway. In the present proposal we hypothesize that lysine acylation regulates FAO enzyme activity, localization to the inner mitochondrial membrane, and the assembly of higher- order metabolic complexes between FAO proteins and the respiratory chain. In Specific Aim 1, we will employ in vitro methods that we pioneered in the previous funding period to identify sirtuin-targeted lysines on the membrane-associated FAO enzymes carnitine palmitoyltransferase-2 (CPT2), mitochondrial trifunctional protein (TFP), and acyl-CoA dehydrogenase-9 (ACAD9). We will perform mutagenesis studies to determine the functional role of each of the sirtuin-targeted lysine residues. In Specific Aim 2 we will investigate physical and functional interactions between the three mitochondrial sirtuins (SIRT3, SIRT4, and SIRT5) and the inner mitochondrial membrane. We hypothesize that the sirtuins police the inner mitochondrial membrane in order to facilitate assembly and operation of higher-order metabolic complexes such as those formed between FAO and the electron transport chain. Finally, Specific Aim 3 will evaluate the effects of lysine acylation on these higher-order complexes using a combination of mouse models and protein complexes assembled in vitro. Understanding the role of the sirtuins in regulating FAO and metabolic supercomplexes will lay the ground work for developing new therapies that manipulate mitochondrial function in human patients with inborn errors of metabolism, as well as those with chronic diseases such as obesity, diabetes, and cancer.