PILOT STUDY--BAYLOR CHILD HEALTH RESEARCH CENTER

电压依赖性阴离子通道(VDAC)是一种小的外部线粒体 存在于所有真核生物中的膜蛋白。VDAC在Close中找到 与ADP转发器通道关联，并直接绑定几个 既以可溶性胞浆形式存在，又以膜结合形式存在的激酶 形式。这组激酶在多种代谢过程中都很重要。 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。这个 已知的与VDAC结合的激酶包括己糖激酶、葡萄糖激酶、甘油 和线粒体肌酸激酶。绑定到VDAC是 以特定于组织的方式进行代谢和发育调节， 并在转化的细胞系中得到增强。据报道， VDAC也存在于其他膜中，已知是 外周苯二氮卓类受体，尽管VDAC在这一过程中的作用 关于这一点，我们不得而知。而分离的两个人VDAC基因是 近年来，人们对VDAC的生理功能知之甚少 在哺乳动物身上。从哺乳动物中鉴定VDAC基因将是非常有用的 更容易被实验操纵，以检验这一假设 VDAC通过结合多种代谢途径参与代谢。 代谢重要的激酶，以及线粒体的呼吸功能 通过受调控的ADP运输。作为解决这些问题的初步步骤 问题我们已经分离出三个不同的VDAC基因。这样做的目的是 项目是通过有针对性的方法在小鼠VDAC基因中产生突变 胚胎干细胞的破坏。此外，每种方法的特殊性 将在酵母表达中研究特定激酶的异构体 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 将研究呼吸功能和电生理特性 在含有VDAC突变的细胞系和突变的小鼠品系中，如果 可行性，将被用来确定VDAC功能的相对重要性 在活体内。尤其是葡萄糖动态平衡和肌肉能量代谢 将进行检查以确定VDAC中是否存在冗余 由于存在多种异构体而起作用。

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.