PACAP: A NOVEL PROAPOPTOTIC CASPASE ADAPTER PROTEIN

描述（由申请人提供）：细胞凋亡或程序性细胞死亡是功能性免疫系统发育和维持的关键过程。细胞凋亡依赖于半胱氨酸蛋白酶（半胱天冬酶）家族，其激活受到负调控机制和正调控机制的影响。最近，我们发现并部分表征了一种新的促凋亡caspase衔接蛋白（PACAP），它与两种起始caspase-2和-9相互作用。到目前为止，我们已经观察到以下情况：当PACAP在细胞系中过表达时，诱导细胞凋亡并激活NF-κ B通路。支持PACAP作为调节蛋白的作用来自于以下观察结果，即在原代人B细胞中内源性表达的PACAP的转录在B细胞活化后快速且显著地下调，而在凋亡期间上调。此外，PACAP与Bcl 10形成复合物，Bcl 10是一种与某些细胞类型中的NF-κ B活化和多种人类恶性肿瘤相关的蛋白质。因此，我们假设PACAP可能用于将细胞外信号引导至casp-2或casp-9凋亡途径，并可能进一步调节在凋亡途径期间激活的其他细胞内途径。为了验证这一假设，我们提出了三个具体的目标，利用分子和细胞生物学，免疫学和生物化学方法，以进一步定义PACAP在生理相关的细胞模型中的性质，其中casp-2和caspase-9在细胞死亡途径中发挥重要作用。建议的具体目标是：1。提供PACAP相互作用的详细生化分析; 2.提供组成PACAP凋亡信号通路的组分的全面定义;和3.进一步鉴定PACAP介导的细胞内信号传导的其他潜在调节因子，重点是NF-κ B途径。 拟议的研究旨在提供有关这种新发现的蛋白质的基本信息，该蛋白质作为与半胱天冬酶-2和-9相关的凋亡途径的调节剂。拟议研究的长期目标是提高我们理解导致与免疫系统功能失调有关的人类疾病的基本过程的能力。

DESCRIPTION (provided by applicant): Apoptosis or programmed cell death is a crucial process for the development and maintenance of a functional immune system. Apoptosis depends upon a family of cysteine proteases (caspases) whose activation is subject to both negative and positive regulatory mechanisms. Recently we discovered and have partially characterized a novel pro-apoptotic caspase adaptor protein (PACAP) that interacts with two initiator caspases, caspase-2 and -9. To date we have observed the following: when PACAP is overexpressed in cell lines, apoptosis is induced and the NF-kappaB pathway is activated. Support for a role for PACAP as a regulatory protein derives from the observations that the transcription of endogenously expressed PACAP in primary human B cells is rapidly and dramatically down regulated after B-cell activation and upregulated during apoptosis. Moreover PACAP forms complexes with Bcl10, a protein linked to NF-kappaB activation in some cell types and to a variety of human malignancies. Thus it is our hypothesis that PACAP may serve to direct extracellular signals to either casp-2 or -9 apoptotic pathways and may further regulate other intracellular pathways activated during the apoptotic pathway. To test this hypothesis we propose three Specific Aims that utilize molecular and cellular biological, immunological and biochemical approaches to further define the properties of PACAP in the context of physiologically relevant cellular models where casp-2 and caspase-9 play essential roles in cell death pathways. The proposed Specific Aims are: 1. To provide a detailed biochemical analysis of PACAP interactions; 2. To provide a comprehensive definition of the components that comprise the PACAP apoptotic signaling pathway; and 3. To provide further identification of other potential regulators of PACAP mediated intracellular signaling with an emphasis on the NF-kappaB pathway. The proposed studies are designed to provide fundamental information about this newly discovered protein that serves as a regulator of apoptotic pathways linked to both caspases-2 and-9. The long term goals of the proposed studies are to enhance our abilities to understand basic processes leading to human diseases linked to a dysfunctional immune system.