PILOT STUDY--BAYLOR CHILD HEALTH RESEARCH CENTER

电压依赖性阴离子通道（VDACs）是线粒体外的小通道， 在所有真核生物中发现的膜蛋白。 VDACs位于靠近 与ADP转运通道关联，并直接结合几个 以可溶性胞质形式和膜结合形式存在的激酶 form. 这组激酶在多种代谢中是重要的。 功能，包括糖酵解，甘油三酯代谢，胰岛素释放， 和胰岛素反应，以及其他代谢途径。 的 已知结合VDAC的激酶包括己糖激酶、葡糖激酶、甘油激酶 激酶和线粒体肌酸激酶。 与VDAC的结合是 以组织特异性方式进行代谢和发育调节， 并且在转化的细胞系中增强。 据报 VDAC也存在于其他膜中，并且已知是膜的组分。 外周苯二氮卓受体，虽然VDAC在这方面的作用， 至于未知。 虽然两个人VDAC基因的分离是 最近的报道，很少有人知道的生理功能的VDACs 在哺乳动物中。 从哺乳动物中鉴定VDAC基因将是非常有用的 更易于实验操作，以验证假设， VDAC通过结合以下物质参与多种代谢途径： 代谢重要的激酶，并在线粒体呼吸功能 通过调节ADP运输。 作为解决这些问题的第一步， 我们已经分离出三种不同的VDAC基因。 这个的目标 项目是通过靶向的方法在小鼠VDAC基因中产生突变， 破坏胚胎干细胞。 此外，每一种的特异性 将在酵母表达中研究特定激酶同种型 系统 靶向基因破坏的目的是评估 VDAC在能量代谢中的相对重要性。 线粒体 呼吸功能和电生理特性将被研究 在携带VDAC突变的细胞系和突变小鼠品系中，如果 可行，将用于确定VDAC功能的相对重要性 in vivo. 特别是葡萄糖稳态和肌肉能量代谢 以确定VDAC中是否存在冗余 由于存在多种异构体，因此具有功能。

Voltage dependent anion channels (VDACs) are small outer mitochondrial membrane proteins found in all eucaryotes. VDACs are found in close association with the ADP translocator channel, and directly bind several kinases that exist both in a soluble cytosolic form and a membrane bound form. This group of kinases is important in a variety of metabolic functions, including glycolysis, triglyceride metabolism, insulin release, and insulin response, in addition to other metabolic pathways. The kinases known to bind VDACs include hexokinase, glucokinase, glycerol kinase, and mitochondrial creatine kinase. Binding to VDACs is metabolically and developmentally regulated in a tissue-specific fashion, and is enhanced in transformed cell lines. It has been reported that VDACs are also found in other membranes and are known to be a component of the peripheral benzodiazepine receptor, although the role of VDACs in this regard is unknown. While the isolation of the two human VDAC genes was recently reported, little is known about the physiologic function of VDACs in mammals. It would be very useful to identify VDAC genes from a mammal more amenable to experimental manipulation, to test the hypothesis that VDACs participate in a variety of metabolic pathways through binding of metabolically important kinases, and in mitochondrial respiratory function via regulated ADP transport. As a preliminary step in addressing these questions we have isolated three distinct VDAC genes. The goals of this project are to create mutations in the mouse VDAC genes through targeted disruption in embryonic stem cells. In addition, the specificity of each isoform for a particular kinase will be studied in a yeast expression system. The objective of targeted gene disruption is to evaluate the relative importance of VDACs in energy metabolism. Mitochondrial respiratory function and electrophysiological properties will be studied in cell lines harboring VDAC mutations, and mutant mouse strains, if viable, will be used to determine the relative importance of VDAC function in vivo. In particular glucose homeostasis and muscle energy metabolism will be examined to determine whether or not there is redundancy in VDAC function due to the presence of multiple isoforms.