BAX Activation and Oligomerization

 描述（申请人提供）：BCL-2相关X蛋白（BAX）是BCL-2蛋白家族的促凋亡成员，在触发细胞凋亡中起重要作用。根据细胞的生理条件，BAX在可溶性（无活性）和线粒体外膜相关构象之间穿梭。在被各种凋亡刺激物激活后，BAX易位到线粒体外膜（mtDNA）并经历一系列构象变化，导致蛋白质寡聚化。最终，寡聚化导致孔的组装，通过孔，致凋亡因子（如细胞色素C）从线粒体膜间空间释放到胞质溶胶，从而引发细胞凋亡。尽管在这一领域进行了广泛的研究，但BAX介导细胞透化的确切机制以及BAX介导的孔的性质和结构仍然难以捉摸。 阐明驱动BAX活化和孔隙形成的结构转变 可以促进治疗剂的开发，所述治疗剂可以潜在地用于治疗具有不充分的细胞凋亡的疾病，例如癌症，或具有过度的细胞凋亡的疾病，例如神经变性疾病。在目标1中，我们将尝试主要使用NMR以及其他生物物理技术来解决膜接合BAX的3D结构。我们还将在结构上表征BAX介导的孔。 一些报道表明BAX与电压依赖性阴离子通道1（VDAC-1）相互作用，但这种相互作用的意义尚不清楚。在目标2中，我们将继续进行VDAC-1/BAX复合物的结构表征。这些目标将有助于我们更好地了解BAX介导的细胞凋亡的机制细节。

 DESCRIPTION (provided by applicant): BCL-2 associated X protein (BAX) is a proapoptotic member of the BCL-2 protein family, which plays an essential role in triggering cell commitment to apoptosis. Depending on the physiological condition of the cell, BAX shuttles between soluble (inactive) and mitochondrial outer membrane-associated conformation(s). Upon activation by various apoptotic stimuli, BAX translocates to the mitochondrial outer membrane (MOM) and undergoes a set of conformational changes leading to protein oligomerization. Ultimately, oligomerization leads to assembly of pores through which apoptogenic factors, such as cytochrome C, are released from the mitochondrial inter- membrane space to the cytosol, thus initiating apoptosis. Despite extensive research in this field, the exact mechanism by which BAX mediates MOM permeabilization as well as the nature and structure of BAX-mediated pores remain elusive. Clarifying the structural transitions that drive BAX activation and pore formation may facilitate the development of therapeutic agents that can potentially be used to treat diseases with inadequate apoptosis, such as cancer, or excessive apoptosis such as neurodegenerative disorders. In Aim 1, we will attempt to solve the 3D structure for membrane-engaged BAX using mainly NMR among other biophysical techniques. We will also structurally characterize the BAX-mediated pore. Several reports have suggested that BAX interacts with voltage dependent anion channel 1 (VDAC-1), however the significance of this interaction is not clear. In Aim 2, we will pursue the structural characterization of the VDAC-1/BAX complex. Together these aims will help us better understand the mechanistic details of BAX-mediated apoptosis.