Dimerization mechanisms of two procaspase subfamilies

两个 procaspase 亚家族的二聚化机制

基本信息

批准号：
8237067
负责人：
ALLAN CLAY CLARK
金额：
$ 28.68万
依托单位：
NORTH CAROLINA STATE UNIVERSITY RALEIGH
依托单位国家：
美国
项目类别：
财政年份：
2003
资助国家：
美国
起止时间：
2003-05-01 至 2014-03-31
项目状态：
已结题

项目摘要

DESCRIPTION (provided by applicant): The mechanisms that lead to the activation of procaspases play central roles in the regulation of apoptosis and inflammation. For all procaspases, formation of a dimer is a critical event in processing because the active sites of the enzyme are comprised of loops contributed by both monomers of the dimer. However, a fundamental difference exists in the caspase subfamilies regarding dimerization and maturation, and this difference is a key aspect for regulating apoptosis. Several inflammatory and initiator procaspases exist as inactive monomers in the cell, but the proteins have relatively high enzymatic activity upon dimerization. For those caspases, chain cleavage simply stabilizes the active site. In contrast, the executioner procaspase-3 is a stable dimer, but it has very little enzymatic activity. In this case, maturation is dependent on cleavage by the initiator procaspases. Our long-term goals are to understand how dimerization, activation and enzymatic activity are coupled for procaspases. Overall, we want to determine why procaspase-1 is a monomer, but yet the active sites form properly upon dimerization. In contrast, we want to determine why the stable dimer of procaspase-3 is not active. We hypothesize that the procaspase dimer exists in two primary conformations, only one of which is active, and that the inactive form is most stable in the case of procaspase-3. Furthermore, we suggest that an allosteric site in the dimer interface affects the conformational switch between the two forms and couples dimerization to active site formation. We have shown that three regions of the protein may be important in affecting the oligomeric state and in stabilizing the inactive form of the procaspase. We propose to use biochemical and biophysical assays, protein folding studies, and X-ray crystallographic studies to examine these three regions of the protein. The procaspase activation mechanisms are important biologically because they allow for the tight regulation of caspase activity in cell death, from maintaining the monomeric state of initiator procaspases to stabilizing the inactive form of dimeric effector procaspases. Understanding the caspase activation process provides a key t develop strategies to intervene in their activities in the cell. PUBLIC HEALTH RELEVANCE: Understanding caspase dimerization and activation has the potential to affect therapeutic strategies for a number of autoimmune diseases, heart disease, and cancers. Learning to selectively manipulate the level of apoptosis is an important step in treatment because the dysregulation of apoptosis is a common factor to these diseases.

描述（由申请人提供）：导致procaspase激活的机制在调节凋亡和炎症的调节中起着核心作用。对于所有procaspase，二聚体的形成是处理中的关键事件，因为酶的活性位点由二聚体的两个单体贡献的环组成。然而，caspase亚家族在二聚化和成熟方面存在基本差异，而这种差异是调节细胞凋亡的关键方面。几种炎症性和引发剂胶囊酶是细胞中无活性单体的存在，但是蛋白质在二聚化时具有较高的酶促活性。对于这些胱天蛋白酶，链条切割简单地稳定了活跃位点。相比之下，执行程序procaspase-3是稳定的二聚体，但酶促活性很小。在这种情况下，成熟取决于引发剂procaspases的裂解。我们的长期目标是了解二聚化，激活和酶促活性是如何耦合的。总体而言，我们想确定为什么procaspase-1是单体，而活跃位点在二聚化时会正确形成。相反，我们要确定为什么procaspase-3的稳定二聚体不活跃。我们假设propaspase二聚体存在于两个主要构象中，其中一种是活跃的，而在procaspase-3的情况下，非活性形式最稳定。此外，我们建议二聚体界面中的变构位点影响两种形式和夫妻二聚体之间的构象开关，以形成主动位点形成。我们已经表明，蛋白质的三个区域对于影响寡聚状态和稳定procaspase的非活性形式可能很重要。我们建议使用生化和生物物理测定，蛋白质折叠研究和X射线晶体学研究来检查蛋白质的这三个区域。 propaspase激活机制在生物学上很重要，因为它们允许细胞死亡中caspase活性的严格调节，从保持启动剂的单体状态来稳定二聚体效应子procaspase的无活性形式。了解caspase激活过程提供了一个关键的t制定策略来干预其在细胞中的活动。公共卫生相关性：了解胱天蛋白酶二聚化和激活有可能影响多种自身免疫性疾病，心脏病和癌症的治疗策略。学习选择性操纵凋亡水平是治疗的重要一步，因为凋亡的失调是这些疾病的常见因素。