Structures of membrane-bound Bcl-2 apoptotic proteins

描述(申请人提供)：Bcl2家族蛋白是程序性细胞死亡的关键调节者，在健康和包括癌症和艾滋病毒-艾滋病在内的主要人类疾病中。它们的促或抗凋亡功能受亚细胞位置的调节，如蛋白质在可溶性和膜结合形式之间循环；通过与其他Bcl-2家族成员的二聚化；通过与其他非同源蛋白质的结合；以及通过形成膜孔来调节细胞凋亡，这些孔被认为通过干扰线粒体的生理作用来调节细胞凋亡。尽管它们具有拮抗活性，但几个促凋亡和抗凋亡的Bcl-2家族成员的溶液结构非常相似，对它们的作用机制提供了不完整的见解。大多数结构和功能研究都集中在可溶性截短的Bcl-2蛋白上，缺乏C末端20个残基的疏水结构域，该结构域存在于许多家族成员中，对膜靶向起重要作用。膜相关蛋白的结构尚不清楚，但有望为研究Bcl2蛋白调控细胞凋亡的机制提供重要的信息。本研究项目的总体目标是确定膜相关的全长Bcl-2家族蛋白的结构。我们提出了一种基于结构-功能的策略，将在脂质环境中进行的核磁共振结构确定与与结构确定并行进行的生物分析相结合。一旦我们实现了这些目标，我们将能够检查修饰(突变、切割、磷酸化、肉豆蔻化)和相互作用(与其他Bcl-2蛋白；与非同源伙伴)的结构后果，因为我们试图进一步了解Bcl-2家族蛋白诱导细胞凋亡和保护细胞的结构基础。

DESCRIPTION (provided by applicant): The Bcl-2 family proteins are key regulators of programmed cell death, in health and major human diseases, including cancer and HIV-AIDS. Their pro- or anti-apoptotic functions are regulated by subcellular location, as the proteins cycle between soluble and membrane-bound forms; by dimerization with other Bcl-2 family members; by binding to other non-homologous proteins; and by formation of membrane pores that are believed to regulate apoptosis by perturbing mitochondrial physiology. Despite their antagonistic activities, the solution structures of several pro- and anti-apoptotic Bcl-2 family members are very similar, and provide incomplete insights to their mechanisms of action. Most of the structural and functional studies have focused on soluble truncated Bcl-2 proteins, lacking the C-terminal 20-residue hydrophobic domain, which is present in many of the family members and important for membrane targeting. The structures of the membrane-associated proteins are not known, but are anticipated to provide important insights to the mechanism of apoptosis regulation by Bcl-2 proteins. The overall goal of this research project is to determine the structures of the membrane-associated, full-length, Bcl-2 family proteins. We propose a structure-function based strategy that combines NMR structure determination in lipid environments with biological assays carried out in parallel with structure determination. Once we accomplish these goals we will be able to examine the structural consequences of modifications (mutations, cleavage, phosphorylation, myristoylation) and interactions (with other Bcl-2 proteins; with non-homologous partners), as we attempt to further understand the structural basis for apoptosis induction and cytoprotection by Bcl-2 family proteins.