Mitochondrial OXPHOS regulation and the Rcf1/Hig1 protein family - a functional link between the ADP/ATP carrier and cytochrome c oxidase enzymes

线粒体 OXPHOS 调节和 Rcf1/Hig1 蛋白家族 - ADP/ATP 载体和细胞色素 C 氧化酶之间的功能联系

• 批准号: 9022129
• 负责人: ROSEMARY A STUART
• 金额: $ 44.43万
• 依托单位: MARQUETTE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-09-07 至 2019-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9022129
• 关键词: Adenine Nucleotide Translocase; Aging; Animal Model; Back; Binding; Bioenergetics; Caliber; Carcinoma; Carrier Proteins; Cells; Communication; Complex; Coupling; Cytochrome bc1 Complex; Data; Diabetes Mellitus; Electron Transport; Electron Transport Complex III; Electrons; Energy-Generating Resources; Environment; Enzymes; FADH2; Family; Family member; Gene Family; Genes; Glucose; Glutamine; Goals; Grant; Health; Homologous Gene; Hypoxia; Impairment; Inner mitochondrial membrane; Interphase Cell; Link; Lipids; Malignant Neoplasms; Membrane; Mentors; Metabolic; Mission; Mitochondria; Mitochondrial Matrix; Molecular; Multienzyme Complexes; Myocardial Ischemia; Myopathy; NADH; Nature; Organism; Oxidases; Oxidative Phosphorylation; Oxidative Stress; Oxygen; Oxygen Consumption; Process; Protein Family; Protein Isoforms; Proteins; Publications; Recycling; Regulation; Research; Research Personnel; Respiration; Role; Saccharomyces cerevisiae; Stress; Students; System; Tail; Taxon; Time; Training; Universities; Water; Yeast Model System; Yeasts; base; complex IV; cytochrome c oxidase; design; enzyme activity; experience; graduate student; innovation; member; mutant; nervous system disorder; oligomycin sensitivity-conferring protein; pH gradient; protein protein interaction; protein transport; public health relevance; research study; respiratory; respiratory protein; response; sensor; undergraduate student

 DESCRIPTION (provided by applicant): Mitochondria produce ATP for the cell's metabolic needs through an oxygen (O2) consuming process called oxidative phosphorylation (OXPHOS). The survival of many organisms is therefore dependent on the availability of O2, which is directly utilized by the cytochrome c oxidase (COX) enzyme of the OXPHOS system. Understanding how mitochondria regulate the activity of the OXPHOS system, in response to different metabolic environments, or limiting O2 conditions (hypoxia), is therefore of fundamental importance. Reduction in the bioenergetic capacity of mitochondria underlies numerous and diverse neurological and muscular diseases. Mitochondrial O2 dysregulation and oxidative stress are also hallmarks of many conditions such as cancers, ischemic heart disease, diabetes and aging. The OXPHOS system is composed of electron transfer complexes (ETC), referred to as complexes I-IV, and the F1Fo-ATP synthase enzyme, also termed complex V. Electrons from substrates are passed via NADH and FADH2 through the ETCs, to reduce O2 to water, a step catalyzed by the COX enzyme (complex IV). ATP is synthesized in the mitochondrial matrix by the F1Fo-ATP synthase, powered by a pH gradient across the inner membrane (IM) and established by the ETC's. The ADP/ATP carrier (AAC) protein transports the ATP out of the mitochondria for distribution to the rest of the cell and also imports ADP, for recycling back to ATP. The OXPHOS enzymes physically associate with each other to form supercomplexes in the IM, e.g. the cytochrome bc1-COX-AAC supercomplex (III-IV-AAC). The supercomplex organization of OXPHOS enzymes is proposed to enable their co-regulation, however, the molecular details of how this is achieved, are not clear. We have identified a protein, termed Rcf1, which binds to Cox3, a regulatory subunit of the COX enzyme. We found that Rcf1 also exists in close physical proximity to the AAC proteins, and in particular to the H2-L-H3 domain, a dynamic region of the AAC protein, critical for its function. Rcf1 is a member of the hypoxia-induced gene family 1 (Hig1), a highly conserved protein family found through all eukaryotic taxa. The Hig1 protein family includes both constitutively-expressed and stress-induced isoforms (e.g. hypoxic, low glucose stress or carcinomas), suggesting their role in modulating OXPHOS activity under conditions of altered metabolic environments. We demonstrate that Rcf1/Hig1 protein supports the enzyme activity of the COX complex, while at the same time interacts with, and influences the function of, AAC proteins. Our proposed experiments are designed to explore if Rcf1 functions as a bioenergetic conformational sensor/regulator coupling the activities of the COX and the AAC proteins, and within context of the cytochrome bc1-COX-AAC supercomplex.

 描述（由申请人提供）：线粒体通过称为氧化磷酸化（OXPHOS）的耗氧（O2）过程产生ATP以满足细胞的代谢需求。因此，许多生物体的存活取决于O2的可用性，O2被OXPHOS系统的细胞色素c氧化酶（考克斯）直接利用。因此，了解线粒体如何调节OXPHOS系统的活性，以响应不同的代谢环境，或限制O2条件（缺氧），具有根本的重要性。线粒体的生物能量能力的降低是许多不同的神经和肌肉疾病的基础。线粒体O2失调和氧化应激也是许多疾病的标志，如癌症、缺血性心脏病、糖尿病和衰老。OXPHOS系统由称为复合物I-IV的电子转移复合物（ETC）和也称为复合物V的F1 Fo-ATP合酶组成。来自底物的电子经由NADH和FADH 2通过ETC，以将O2还原成水，这是由考克斯酶（复合物IV）催化的步骤。ATP在线粒体基质中由F1 Fo-ATP合酶合成，由跨内膜（IM）的pH梯度提供动力，并由ETC建立。ADP/ATP载体（AAC）蛋白将ATP从线粒体中转运出来，分配到细胞的其他部分，并输入ADP，再循环回ATP。OXPHOS酶彼此物理结合以在IM中形成超复合物，例如细胞色素bc 1-COX-AAC超复合物（III-IV-AAC）。OXPHOS酶的超复杂组织被提出以使它们能够共同调节，然而，如何实现这一点的分子细节尚不清楚。我们已经确定了一种蛋白质，称为Rcf 1，它结合到Cox 3，一个调节亚基的考克斯酶。我们发现，Rcf 1也存在于物理上接近AAC蛋白，特别是H2-L-H3结构域，AAC蛋白的动态区域，其功能的关键。Rcf 1是缺氧诱导基因家族1（Hig 1）的成员，Hig 1是在所有真核生物中发现的高度保守的蛋白质家族。Hig 1蛋白家族包括组成型表达和应激诱导的同种型（例如低氧、低葡萄糖应激或癌），表明它们在改变的代谢环境条件下调节OXPHOS活性的作用。我们证明，Rcf 1/Hig 1蛋白支持酶活性的考克斯复合物，而在同一时间相互作用，并影响AAC蛋白的功能。我们提出的实验的目的是探讨如果Rcf 1功能作为一个生物能量的构象传感器/调节器耦合的活动的考克斯和AAC蛋白，并在上下文中的细胞色素bc 1-COX-AAC超复合物。