Novel Roles for Effector Procaspases

效应器蛋白酶原的新作用

• 批准号: 9042395
• 负责人: Lawrence H. Boise
• 金额: $ 29.64万
• 依托单位: EMORY UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-08-01 至 2018-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9042395
• 关键词: Actins; Adaptor Signaling Protein; Adherence; Adhesions; Anoikis; Apoptosis; Apoptotic; Aspartate Ammonia-Lyase; Aspartic Acid; CASP1 gene; CASP3 gene; CASP7 gene; CASP8 gene; Caspase; Cell Adhesion; Cell Death; Cell Death Process; Cell Proliferation; Cell Survival; Cell membrane; Cell physiology; Cell-Cell Adhesion; Cells; Cellular Morphology; Cleaved cell; Complex; Cues; Cysteine; Cytoskeletal Modeling; Cytoskeleton; Cytosol; Data; Data Analyses; Dendritic Spines; Development; Disease; Disseminated Malignant Neoplasm; Drosophila genus; Embryo; Embryonic Development; Enzyme Precursors; Erythrocytes; Eukaryotic Cell; Event; Extracellular Matrix; Feedback; Fibroblasts; Fibronectins; Forms Controls; Health; Immune response; Infection; Inflammatory; Inflammatory Response; Length; Lens Fiber; Light; Mitochondria; Modeling; Morphology; Mus; Necrosis; Occupations; Phenotype; Play; Process; Proteins; Regulation; Research; Role; Signal Transduction; Stress; Structure; Subgroup; Synaptic plasticity; T-Lymphocyte; Therapeutic; Thinking; Virus; Wound Healing; base; cell killing; cell motility; cytochrome c; cytokine; design; dimer; feeding; fiber cell; migration; mitochondrial dysfunction; mutant; novel; response; sperm cell

DESCRIPTION (provided by applicant): Caspases are cysteine aspartases found in all eukaryotic cells as zymogens that require induced proximity and/or proteolytic cleavage for activation. Activated caspases function as both regulators and executioners of cell death in response to developmental cues or environmental stress (e.g. apoptosis) and infections (e.g. pyroptosis and necroptosis). Activated caspases can have equally profound systemic effects by controlling inflammatory responses through cytokine maturation as well as induction of cell proliferation and migration in the wound-healing response (e.g. the "phoenix rising" phenomena). Therefore there has been a significant amount of research on the mechanism of caspase activation and the function of active caspases since aberrant activation could have catastrophic consequences for the cell. It has long been presumed that the zymogens of caspases (procaspases) had no function and were only present to allow for a quick and decisive means for a cell to induce cell death or an inflammatory response. While studying the role of the effector caspases-3 and -7 on mitochondrial function following cytochrome c release, we serendipitously discovered novel functions for procaspase-3 and procaspase-7 that shed new light on why cells carry killer molecules. Mouse embryo fibroblasts (MEFs) that are deficient in casp3 display enhanced adhesion and altered migration velocity that is associated with increased fibronectin secretion. Introduction of procaspase-3 or a procaspase-3 that is catalytically inactive reverses this phenotype. Casp7-deficient MEFs have altered morphology and loss of directionally-persistent migration. These events appear to be associated with altered actin cytoskeleton organization and are also independent of caspase activity. Thus effector procaspases are not only poised killer molecules, they have cellular functions in viable cells. The first two Specific Aims of this application are designed to determine how these effector procaspases regulate cell adhesion, migration and secretion. Additionally we have found that the survival advantage observed with casp3-deficient MEFs is dependent on cell adhesion. Casp3-deficient cells are not protected against loss of adherence to extracellular matrix (anoikis). This suggests that the non-apoptotic functions of procaspase-3 can also influence the cellular response to apoptotic signals. This would have a significant impact on current models of feed-forward loops that have been proposed to explain how an effector caspase could influence events that occur upstream of caspase activation. Therefore the final Specific Aim of this application will re-examine the mechanism by which loss of casp3 alters cell survival. Completion of these Aims will have a paradigm-shifting effect on how we think about procaspases and may require a re-interpretation of data generated with caspase-deficient cells.

描述(由申请人提供)：半胱氨酸天冬氨酸酶是存在于所有真核细胞中的半胱氨酸天冬氨酸酶，需要诱导邻近和/或蛋白水解性切割才能激活。激活的caspase既是细胞死亡的调节者，也是细胞死亡的执行者，以响应发育线索或环境应激(如细胞凋亡)和感染(如上睑下垂和坏死性下垂)。激活的caspase可以通过细胞因子成熟来控制炎症反应，以及在伤口愈合反应中诱导细胞增殖和迁移，从而具有同样深刻的全身效应(例如，“凤凰升起”现象)。因此，人们对caspase的激活机制和活性caspase的功能进行了大量的研究，因为异常的激活可能会对细胞造成灾难性的后果。长期以来，人们一直认为caspase(原天冬氨酸氨基转移酶)的酶原没有任何功能，它的存在只是为了使细胞能够以一种快速而决定性的方式诱导细胞死亡或炎症反应。在研究caspase-3和-7在细胞色素c释放后对线粒体功能的作用时，我们偶然发现了proaspase-3和proaspase-7的新功能，这为细胞为什么携带杀伤分子提供了新的线索。缺乏casp3的小鼠胚胎成纤维细胞(MEF)表现出粘附性增强和迁移速度改变，这与纤维连接蛋白分泌增加有关。引入proaspase-3或催化失活的proaspase-3可以逆转这一表型。Casp7缺陷的MEF改变了形态和失去了定向持续迁移。这些事件似乎与肌动蛋白细胞骨架结构的改变有关，也与caspase活性无关。因此，效应器原天冬氨酸酶不仅是稳定的杀手分子，它们在活细胞中也具有细胞功能。这项应用的前两个特定目标旨在确定这些效应性原天冬氨酸酶如何调节细胞黏附、迁移和分泌。此外，我们还发现，casp3缺陷的MEF的生存优势依赖于细胞黏附。Casp3缺失的细胞不受细胞外基质(失巢凋亡)黏附丧失的保护。这表明，原天冬氨酸蛋白酶-3的非凋亡功能也可以影响细胞对凋亡信号的反应。这将对目前提出的前馈循环模型产生重大影响，这些模型被用来解释效应器caspase如何影响caspase激活上游发生的事件。因此，这项应用的最终特定目标将重新检查casp3丢失改变细胞存活的机制。完成这些目标将对我们思考原天冬氨酸酶的方式产生范式转换的影响，并可能需要重新解释由caspase缺陷细胞产生的数据。