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）：胱天蛋白酶是在所有真核细胞中发现的半胱氨酸天冬氨酸，是需要诱导的接近性和/或蛋白水解裂解以激活的Zymogens。激活的胱天蛋白酶在响应发育线索或环境压力（例如凋亡）和感染（例如凋亡和坏死性）的发育线索或环境压力（例如凋亡）和环境压力（例如凋亡）和环境压力（例如，凋亡）时起到了细胞死亡的调节作用。活化的胱天蛋白酶通过通过细胞因子成熟来控制炎症反应，以及伤口控制反应中细胞增殖和迁移的诱导（例如，“凤凰城的上升”现象），可以产生同样深刻的全身效应。因此，关于胱天蛋白酶激活的机制和活动胱天蛋白酶的功能已经进行了大量研究，因为异常激活可能会对细胞产生灾难性的后果。长期以来，人们一直认为，胱天蛋白酶的酶原（procaspases）没有功能，并且仅存在以允许细胞诱导细胞死亡或炎症反应的快速而决定性的手段。在研究细胞色素c释放后效应子caspase-3和-7对线粒体功能的作用时，我们偶尔发现了procaspase-3和procaspase-7的新功能，这些功能对细胞为何携带杀伤分子的原因进行了新的启示。 CASP3缺乏的小鼠胚胎成纤维细胞（MEF）表现出增强的粘附和改变与纤连蛋白分泌增加有关的迁移速度。引入催化无效的procaspase-3或procaspase-3会逆转该表型。 CASP7缺乏的MEF改变了形态和方向存在的迁移的丧失。这些事件似乎与肌动蛋白细胞骨架组织的改变有关，并且与caspase活性无关。因此，效应子procaspase不仅是固定的杀伤分子，而且在活细胞中具有细胞功能。该应用程序的前两个具体目的旨在确定这些效应procaspase如何调节细胞粘附，迁移和分泌。另外，我们发现使用CASP3缺乏的MEF观察到的生存优势取决于细胞粘附。 CASP3缺陷的细胞不受对细胞外基质（Anoikis）的依从性丧失的保护。这表明procaspase-3的非凋亡功能也会影响细胞对凋亡信号的反应。这将对当前提出的馈电回路模型产生重大影响，这些模型已提出，以解释效应子caspase如何影响caspase激活上游发生的事件。因此，本应用的最终特定目的将重新检查CASP3损失改变细胞存活的机制。这些目标的完成将对我们对procaspases的看法产生范式转移影响，并且可能需要重新解释用caspase缺陷细胞生成的数据。