The Role of Mitochondrial VDACs in Apoptosis

描述(申请人提供)：细胞凋亡的过程在胚胎发育、免疫功能、组织动态平衡和癌症监测中发挥着重要作用。了解细胞凋亡的分子机制将对心力衰竭、癌症化疗和脑血管事件等各种疾病的治疗产生重大影响。到目前为止，已经定义了两条广泛的途径：一条内源途径，依赖于线粒体外膜上的死亡信号对包括内质网应激在内的各种触发因素的响应；另一条外源途径，依赖于质膜信号，但也涉及通过线粒体放大信号。线粒体通透性转换孔(MPTP)既有涉及多种促和抗凋亡蛋白的信号机制，也有涉及线粒体外膜、内膜和基质室蛋白复合体的生物能量学机制。这项建议涉及线粒体外膜的通道蛋白；电压依赖性阴离子通道，特别是VDAC2，在改变线粒体通透性、与促凋亡蛋白(如BAK)相互作用和激活细胞凋亡中的作用。我们假设线粒体在外膜的通透性(VDAC)和跨内外膜的通透性(MPTP)都调节细胞凋亡和正常生理方面。具体目的1将确定VDAC2在调节促凋亡蛋白亚细胞位置和功能中的作用。特定目标2将定义基因工程培养细胞中MPTP的成分。特异靶向3将利用基因靶向的小鼠检测VDAC2在细胞凋亡中的体内功能。这些研究将有助于确定线粒体通透性如何调节生理和病理生理细胞事件，并验证这些蛋白质在各种疾病状态下作为潜在治疗靶点的有效性。公共卫生相关性：该项目的目标是确定在线粒体外膜中发现的通道蛋白在激活和控制细胞死亡中的作用，这是一个高度调控的过程，在哺乳动物(包括人类)的正常发育、感染控制和避免癌症方面具有关键作用。利用遗传和生化技术，结合基因工程培养的细胞和小鼠，目的是确定这些渠道是治疗干预的潜在目标。

DESCRIPTION (provided by applicant): The process of apoptosis plays an important role in embryonic development, immune function, tissue homeostasis and cancer surveillance. Understanding the molecular mechanisms that underlay apoptosis should have a significant impact on therapies for such diverse disorders as heart failure, cancer chemotherapy, and cerebrovascular events. To date, two broad pathways have been defined: an intrinsic pathway that depends on integrating death signals at the mitochondrial outer membrane in response to a variety of triggers, including ER stress, and an extrinsic pathway that relies on signals from the plasma membrane but also involves amplification of the signal via mitochondria. There is both a signaling mechanism involving a number of pro- and anti-apoptotic proteins and a bioenergetic mechanism involving a protein complex composed of mitochondrial outer membrane, inner membrane and matrix compartment proteins termed the mitochondrial permeability transition pore (MPTP). This proposal addresses the role of channel proteins of the mitochondrial outer membrane; Voltage dependent Anion Channels, and specifically VDAC2, in altering mitochondrial permeability, interacting with pro-apoptotic proteins such as BAK, and in the activation of apoptosis. We hypothesize that mitochondrial permeability at the outer membrane (VDACs) and across both the inner and outer membranes (MPTP) both regulates aspects of apoptosis and normal physiology. Specific aim 1 will determine the role of VDAC2 in regulating pro-apoptotic protein subcellular location and function. Specific aim 2 will define the components of the MPTP in genetically engineered cultured cells. Specific aim 3 will examine the in vivo functions of VDAC2 in apoptosis using gene targeted mice. These studies will help determine how mitochondrial permeability acts to regulate both physiologic and pathophysiologic cellular events, and validate the proteins as potential therapeutic targets in a variety of disease states. PUBLIC HEALTH RELEVANCE: The goal of this project is to determine the role of channel proteins found in the mitochondrial outer membrane in the activation and control of cell death, a highly regulated process that has a crucial role in normal development, control of infections, and avoidance of cancer in mammals, including humans. Using genetic and biochemical techniques, in combination with genetically engineered cultured cells and mice, the aim is to establish that these channels are potential targets for therapeutic interventions.