PROTEINS IMPORTANT FOR PROGRAMMED CELL DEATH AND FOR GENE-LINKED BLINDNESS

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 细胞凋亡抑制因子（Inhibitors of apoptosis，IAP）是一种能够阻断细胞死亡的抗凋亡因子。 IAP含有蛋白质-蛋白质相互作用结构域和赋予E3泛素连接酶活性的C-末端RING结构域。 小分子拮抗剂与细胞IAP的结合促进cIAP自身泛素化和随后的蛋白酶体降解，从而释放cIAP对细胞凋亡的抑制？这种情况可能会使一些癌症治疗更有效。 远距离拮抗剂结合事件如何影响物理上不同的RING结构域的E3连接酶活性尚不清楚。 我们的初步数据支持一种假设，即拮抗剂结合导致结构重排，允许形成活性RING-RING二聚体。 此外，拮抗剂还可以促进中等大小的cIAP 1群体;大于单体，但小于二聚体。 这种形式的cIAP 1是一个特定的单价拮抗剂的存在下，占主导地位的物种，并可能代表？开着？但未二聚化的蛋白质 我们寻求小分子拮抗剂存在和不存在下的cIAP 1的SAXS数据。 Htra 1是一种多结构域蛋白酶。人类Htra 1基因变异促进过度表达并增加对年龄相关性黄斑变性的易感性Htra 1由四个结构域组成，其分子形状通过同源性已知，并且其蛋白酶活性需要形成1440个氨基酸的非共价同源三聚体。非蛋白酶结构域的功能作用尚不清楚。 由IGFBP-rP和Kazal结构域组成的N-末端结构域在细菌同源物中不存在，表明其具有独特的调节功能。我们的目标是了解三聚体中的结构域位置，潜在的结构域相互作用和结构域寡聚化状态。此外，我们有抗Htra 1抗体片段，可以帮助SAXS分析。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Inhibitors of apoptosis (IAPs) are anti-apoptotic factors that block cell death. IAPs contain protein-protein interaction domains and a C-terminal RING domain that confers E3 ubiquitin ligase activity. Binding of small molecule antagonists to cellular IAPs promotes cIAP auto-ubiquitination and subsequent proteasomal degradation, thereby releasing cIAP inhibition of apoptosis?a situation that may render some cancer therapies more effective. How the distant antagonist binding event influences the E3 ligase activity of the physically distinct RING domain is unclear. Our preliminary data support a hypothesis where antagonist binding leads to a structural rearrangement that permits formation of active RING-RING dimers. Moreover, antagonists can also promote a cIAP1 population of intermediate size; larger than monomer, yet smaller than a dimer. This form of cIAP1 is the dominant species in the presence of a particular monovalent antagonist and may represent the ?open?, but un-dimerized, form of the protein. We seek SAXS data from cIAP1 both in the absence and presence of small molecule antagonists. Htra1 is a multi-domain protease. A variant human Htra1 gene promotes overexpression and increases susceptibility to age-related macular degeneration. Htra1 is composed of four domains for which molecular shapes are known by homology and its protease activity requires formation of a non-covalent homotrimer of 1440 amino acids. The functional roles of the non-protease domains are not clear. The N-terminal domain composed of the IGFBP-rP and Kazal domains is absent in baterial homologues, suggesting a unique regulatory function. Our objective is to learn the domain locations in the trimer, potential domain interactions and domain oligomerization status. In addition, we have anti-Htra1 antibody fragments which may aid in SAXS analysis.