Reversible Mitochondrial Protein Acetylation and Metabolic Regulation

 描述(由申请人提供)：这是R24资助的竞争性更新，重点是线粒体蛋白酰化，它由依赖NAD的线粒体蛋白脱乙酰酶SIRT3和SIRT5调节，以及它们在正常和病理条件下对代谢调节的影响。在这笔赠款的头48个月里，我们的合作小组发表了27篇论文，并将SIRT3和SIRT5的功能定义为关键的线粒体NAD依赖蛋白脱酰酶。在线粒体中，SIRT3和SIRT5调节许多线粒体关键代谢途径中的乙酰化(SIRT3)和琥珀酸化(SIRT5)，包括脂肪酸氧化、酮体合成、TCA循环、OXPHOS和尿素循环。SIRT3的缺失与代谢灵活性降低和综合征的加速发展有关，这种综合征类似于人类的代谢综合征，表现为肥胖、2型糖尿病、血脂异常和脂肪性肝炎。缺乏SIRT5的小鼠在尿素循环、酮生成和脂肪酸氧化方面也表现出显著的代谢异常。SIRT5也是一种依赖NAD的去丙二酸酶，但这种修饰主要针对细胞质中的不同蛋白质。这些发现表明，可逆的线粒体蛋白酰化是线粒体代谢的关键调节因素，SIRT3和SIRT5是2型糖尿病和代谢综合征发病机制中的重要因素。这项建议的总体目标是扩展这些研究，以进一步确定蛋白质酰化以及SIRT3和SIRT5在参与代谢综合征发病机制的独特组织：肝脏、肌肉和胰腺细胞中的线粒体功能中的作用。我们将利用我们高度协作的多学科团队，利用基于质谱学的蛋白质组学、代谢组学、分子生物学、广泛的生理测试以及独特和新颖的动物模型，包括组织特异性基因敲除和组织特异性SIRT3和SIRT5转基因过表达基因，进一步加深我们对线粒体功能和代谢调节中这一重要过程的理解。

 DESCRIPTION (provided by applicant): This is a competitive renewal of an R24 grant focused on mitochondrial protein acylation, its regulation by the NAD-dependent mitochondrial protein deacylases, SIRT3 and SIRT5, and their impact on metabolic regulation under normal and pathological conditions. During the first 48 months of this grant, our collaborative group has published 27 papers and has defined the function of SIRT3 and SIRT5 as key mitochondrial NAD-dependent protein deacylases. In the mitochondria, SIRT3 and SIRT5 regulates the acetylation (SIRT3) and succinylation (SIRT5) of many mitochondrial enzymes in key metabolic pathways that include fatty acid oxidation, ketone body synthesis, TCA cycle, OXPHOS and the urea cycle. Loss of SIRT3 is associated with reduced metabolic flexibility and accelerated development of a syndrome that mimics human metabolic syndrome with obesity, type 2 diabetes, lipid abnormalities, and steatohepatitis. Mice lacking SIRT5 also showed significant metabolic abnormalities in the urea cycle, ketogenesis and fatty acid oxidation. SIRT5 is also an NAD-dependent demalonylase but this modification targets distinct proteins predominantly in the cytoplasm. These findings point to reversible mitochondrial protein acylation as a key regulator of mitochondrial metabolism and SIRT3 and SIRT5 as important factors in the pathogenesis of type 2 diabetes and the metabolic syndrome. The overall goal of this proposal is to extend these studies to further define the role of protein acylation and SIRT3 and SIRT5 in mitochondrial function in unique tissues involved in the pathogenesis of the metabolic syndrome: liver, muscle and pancreatic ß cells. We will take advantage of our highly collaborative and multidisciplinary team harnessing the power of mass spectrometry-based proteomics, metabolomics, molecular biology, extensive physiological testing and unique and novel animal models, including tissue-specific knockouts and tissue specific transgenic overexpressors for SIRT3 and SIRT5, to further increase our understanding of this important process in regulation of mitochondrial function and metabolism.