Structural and Functional Analysis of Cardiolipin-Associated Bax

癌症的产生是由于受损细胞无法启动信号级联反应， 破坏细胞并清除体内的毒素这一过程被称为细胞凋亡， 防止导致癌症的受损细胞的繁殖。一个被称为Bcl-2蛋白的蛋白质家族 家族调节细胞凋亡。Bcl-2蛋白家族通过以下相互作用促进细胞死亡： 死亡促进蛋白Bax是该家族的促凋亡成员，通过以下途径启动细胞死亡级联反应： 释放细胞色素C。Bax具有通过与细胞色素C结合作用来介导细胞色素C释放的能力。 心磷脂先前的研究表明，心磷脂的存在增强了Bax形成的能力， 通过一种目前尚不清楚的机制在重组膜中形成孔隙。我们实验室的初步数据 已经开始阐明Bax与心磷脂相互作用的机制。存在下 心磷脂Bax经历了一种独特的构象变化， 模型膜。当前项目的目标是确定这种构象的影响， Bax的活性和功能构象发生了变化。我们的目标是详细说明 并将这些变化与膜上Bax的功能联系起来。这将通过研究 用荧光光谱法研究膜相关Bax的孔形成和寡聚化 技术.我们还将研究Bax区域如何有助于膜识别孔的形成， 通过使用突变体的寡聚化。Bax的两个感兴趣的区域是BH 3结构域， 也称为推定的心磷脂结合区和C-末端疏水结构域。理解 孔的形成和寡聚化的机制以及Bax的结构域如何有助于 膜活性构象将增强我们对细胞凋亡的理解，并有助于我们 克服癌细胞为逃避凋亡而建立的屏障。

Cancer arises as a result of the inability of damaged cells to initiate a signaling cascade that results in the destruction of the cell and clearance from the body. This process, known as apoptosis, is necessary to prevent reproduction of damaged cells that leads to cancer. A family of proteins known as the Bcl-2 protein family regulates apoptosis. The Bcl-2 protein family works to promote cell death through the interaction of death promoting proteins. Bax, a pro-apoptotic member of this family, initiates the cell death cascade by releasing cytochrome C. Bax has the ability to mediate cytochrome c release by working in conjunction with cardiolipin. Previous studies have shown that the presence of cardiolipin enhances the ability of Bax to form pores in reconstituted membranes through an, as yet, unknown mechanism. Preliminary data from our lab has begun to elucidate the mechanism of interaction between Bax and cardiolipin. In the presence of cardiolipin Bax undergoes a unique conformational change that facilitates the release of molecules from model membranes. The goals of the current project are to determine the impact that this conformational change has on the active and functional conformation of Bax. Our goals are to detail the structural changes and to correlate these changes with the function of Bax at the membrane. This will be achieved by studying pore formation and oligomerization of membrane-associated Bax using fluorescent spectroscopic techniques. We will also study how regions of Bax contribute to membrane recognition pore formation and oligomerization through the use of mutants. The two regions of Bax that are of interest are the BH3 domain, also called the putative cardiolipin binding region, and the c-terminal hydrophobic domain. Understanding the mechanisms of pore formation and oligomerization as well as how domains of Bax contribute to the membrane-active conformation will enhance our understanding of apoptosis and aid in our ability to overcome the barriers that cancer cells erect to evade apoptosis.