Maintenance of the metabolic homeostasis of the heart - Developing a systems analysis approach
Maintenance of the metabolic homeostasis of the heart - Developing a systems analysis approach
复制标题
DOI：
10.1196/annals.1380.013
复制
发表时间：
2006-01-01
期刊：
影响因子：
--
通讯作者：
Balaban, Robert S.
中科院分区：
文献类型：
--
作者：
Balaban, Robert S.
心脏在人体中几乎是独一无二的，它不断要求进行远远超出正常维持细胞完整性的工作。在这种恒定的工作负荷下，心脏能量转换高度专业化以维持恒定的能量供应也就不足为奇了。在工作量变化期间细胞代谢物的维持被称为代谢稳态。在这里，我们讨论我们为了解协调心脏代谢稳态的细胞和线粒体控制网络所做的努力。首先是更好地定义代谢途径、急性翻译后控制位点以及对完整线粒体环境中的反应步骤进行适当的动力学评估。首先，提出了线粒体能量转换的定量模型，并展示了我们对该过程的认识中存在的几个严重差距。为了填补这些空白，我们对整个线粒体蛋白质组进行了筛选，以确定需要考虑的代谢途径。此外，使用 2D 凝胶电泳与 (32)p 标记结合的完整线粒体的动态磷酸化蛋白质组揭示了整个线粒体代谢网络中非常广泛的蛋白质磷酸化网络，而该网络基本上被忽视了。将回顾评估这些蛋白质磷酸化和所涉及的激酶磷酸酶系统的功能意义的初步研究。解释完整线粒体活性的氧化磷酸化共识定量模型的主要缺陷之一是在复合物 1 中，使用体外动力学数据，即使烟酰胺腺嘌呤二核苷酸（NADH）氧化的启动也是有问题的。将描述使用荧光寿命和光氧化后酶依赖性荧光恢复 (ED-FRAP) 技术确定完整线粒体中复合物 I 的 NADH 结合和氧化动力学的研究。这些后来的研究表明，基质 NADH 结合特征与分离的蛋白质有很大不同（> 10(3) 结合常数误差）。此外，复合物 I 远未达到平衡，可能在调节细胞色素等量递送减少率方面发挥重要作用。
The heart is almost unique in the body with a constant requirement to conduct work well beyond the normal maintenance of cellular integrity. With this constant workload, it is not surprising that cardiac energy conversion is highly specialized to maintain a constant supply of energy. This maintenance of cellular metabolites during alterations in workload has been termed metabolic homeostasis. Here we discuss our efforts to understand the cellular and mitochondrial control network that orchestrates the metabolic homeostasis of the heart. This begins with a better definition of the metabolic pathways, acute posttranslational control sites, and proper kinetic evaluation of the reaction steps in the intact mitochondrial environment. First, a quantitative model of mitochondrial energy conversion is presented and demonstrates several serious gaps in our knowledge of this process. Toward filling these gaps, screens of the entire mitochondrial proteome have been conducted to establish the metabolic pathways that need to be considered. In addition, the dynamic phosphoproteome of intact mitochondria, using 2D gel electrophoresis coupled to (32)p labeling, has revealed a remarkably extensive protein phosphorylation network throughout the mitochondrial metabolic network that has essentially been overlooked. Initial studies on evaluating the functional significance of these protein phosphorylations and the kinase-phosphatase system involved will be reviewed. One of the major deficits in the consensus quantitative model of oxidative phosphorylation to explain intact mitochondria activities is in complex 1, where even the initiation of Nicotinamide Adenine Dinucleotide (reduced) (NADH) oxidation is problematical using in vitro kinetic data. Studies will be described where the NADH binding and oxidation kinetics at complex I in the intact mitochondria were determined using fluorescence lifetime and enzyme dependent-fluorescence recovery after photo-oxidation (ED-FRAP) techniques. These later studies suggest that matrix NADH binding characteristics are much different (> 10(3) binding constant errors) than isolated proteins. In addition, complex I is far from equilibrium and may play an important role in regulating the rate of reducing equivalent delivery to the cytochromes.