Function of intramembrane aspartic protease

膜内天冬氨酸蛋白酶的功能

• 批准号: 7666816
• 负责人: EVGENY I ROGAEV
• 金额: $ 33.5万
• 依托单位: UNIV OF MASSACHUSETTS MED SCH WORCESTER
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-08-01 至 2013-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7666816
• 关键词: Aging-Related Process; Alzheimer' s Disease; Anencephaly; Animal Model; Animals; Apoptosis; Apoptotic; Aspartic Endopeptidases; Biological Assay; Brain; Brain Pathology; Caenorhabditis elegans; Cell Death; Cell physiology; Cells; Data; Defect; Development; Embryo; Embryonic Development; Environmental Risk Factor; Event; Exencephalies; Family; Generations; Genes; Genetic; Growth; Human; Indium; Integral Membrane Protein; Invertebrates; Knock-out; Knockout Mice; Lead; Lipids; Mammals; Mitochondria; Modeling; Molecular; Molting; Mouse Strains; Mus; Mutation; Names; Neural Tube Defects; Neural Tube Development; Neural tube; Orthologous Gene; Pathway interactions; Peptide Hydrolases; Perinatal; Phenotype; Population; Process; Property; Proteins; Regulation; Role; Signal Pathway; Signal Transduction; Specific qualifier value; Spinal Cord; Staging; System; Testing; Vertebrates; Wild Animals; brain tissue; familial Alzheimer disease; in utero; in vivo; insight; knockout animal; loss of function; member; mouse model; notch protein; novel; positional cloning; presenilin; presenilin-1; presenilin-2; public health relevance; receptor; receptor-mediated signaling

DESCRIPTION (provided by applicant): The objective of this project is to test the hypothesis that a recently identified putative polytopic intramembrane protease (IMPAS1/IMP1) is a critical regulator of brain development. We postulate that IMPAS1 acts via control of a lipid-dependent evolutionary-conserved signaling system. Mutations in two homologous presenilin genes, PS1 and PS2, are the cause of familial Alzheimer's disease (AD). PSs are required for Notch1 receptor-mediated signaling in early development. We and others have recently identified a novel family of diverged proteins (IMPAS (IMP) or SPP/SPPL) structurally related to presenilins. The function of IMP proteins in vivo is unknown. We have found that Ce-imp-2, homologous to human hIMP1, is a critical regulator of a specific development pathway in C. elegans. We recently obtained preliminary data for the generation of knockout mice for mIMP1 and made primary observations that the major phenotypes of the mIMP1 knockout animals are severe brain development defects: exencephaly (brain overgrowth) and anencephaly (brain depletion). In this project we propose to test the following hypotheses. 1) The function of IMP1 is to control neurulation. 2) Inactivation of hIMP1 will lead to brain abnormalities, including neural tube defects and anencephaly, a common cause of perinatal lethality or severe brain pathology in humans. 3) IMPAS proteins are novel essential components of the specific lipid-dependent signaling pathways controlling development. We anticipate that this pathway is connected to Wnt- downstream signaling, and deficiency in IMP1 impairs this signaling leading to spatio-temporal alterations in processes of programmed cell death during a critical stage of neural tube development. The hypotheses will be tested by pursuing the following specific aims: Aim 1. To determine the role of IMPAS1 in neurulation and development. We will complete the generation of knockout mIMP1-/- mouse strains and will elucidate phenotypes induced by a loss of function of IMP1 in mice. Detailed comparisons of both brain and non-brain phenotype IMP1-deficient animals and wild type animals will be made to predict the putative pathway controlled by IMP1. We will also determine whether exencephaly and anencephaly are related phenotypes; and what genetic-environmental factors may modify the abnormal neurulation in IMP1 knockout animals leading to anencephaly, a common congenital brain defect in humans. Aim 2. To elucidate molecular pathways regulated by IMP1 gene in vivo. Using molecular signaling assays, examination of spatial-temporal expression of specific markers and transcriptional effectors we will identify whether molecular alterations in IMP1-deficiency animals are similar to those found in animals with impaired signaling essential for normal neurulation and whether IMP1 interact with Wnt- signaling. Aim 3. To determine whether regulation of programmed cell death is impaired in IMP1-deficient animals. We will determine whether IMP1- deficiency is associated with defects in the processes of programmed cell death, differentiation and proliferation during brain development. We will determine whether IMP1 is important for regulation of apoptosis via Wnt-dependent or independent pathway. PUBLIC HEALTH RELEVANCE: The study of recently identified multipass transmembrane protein (IMPAS1/IMP1) will provide insight into the mechanisms involved in normal and abnormal brain development and regulation of programmed cell death. The gene for the IMP1 protein is structurally related to Alzheimer's disease presenilins. We found in our preliminary data that this protein may be an essential regulator in the formation of the neural tube fundamental event of embryogenesis. We plan to provide evidence for the essential role of this protein in CNS development and signaling in neurulation, which if disrupted, underlies anencephaly, a most common congenital brain defect in humans.

描述（由申请人提供）：本项目的目的是检验一种假设，即最近鉴定的假定多位膜内蛋白酶（IMPAS 1/IMP 1）是大脑发育的关键调节因子。我们假设IMPAS 1通过控制脂质依赖的进化保守信号系统发挥作用。两个同源早老素基因PS1和PS2的突变是家族性阿尔茨海默病（AD）的病因。PS是Notch 1受体介导的早期发育信号所必需的。我们和其他人最近已经确定了一个新的家庭分歧的蛋白质（IMPAS（IMP）或SPP/SPPL）结构相关的早老素。IMP蛋白在体内的功能尚不清楚。我们发现Ce-IMP-2与人hIMP 1同源，是C.优美的我们最近获得了mIMP 1基因敲除小鼠的初步数据，并初步观察到mIMP 1基因敲除动物的主要表型是严重的脑发育缺陷：露脑畸形（脑过度生长）和无脑畸形（脑耗竭）。在这个项目中，我们提出测试以下假设。1)IMP 1的功能是控制神经形成。2)hIMP 1的失活将导致脑异常，包括神经管缺陷和无脑畸形，这是人类围产期死亡或严重脑病理的常见原因。3)IMPAS蛋白是控制发育的特定脂质依赖性信号通路的新的必需组分。我们预期该途径与Wnt下游信号传导有关，并且IMP 1的缺陷损害该信号传导，导致在神经管发育的关键阶段期间程序性细胞死亡过程中的时空改变。这些假设将通过追求以下具体目标进行测试：目标1。确定IMPAS 1在神经形成和发育中的作用。我们将完成敲除mIMP 1-/-小鼠品系的产生，并将阐明小鼠中IMP 1功能丧失诱导的表型。将对脑和非脑表型IMP 1缺陷动物和野生型动物进行详细比较，以预测IMP 1控制的推定途径。我们还将确定露脑畸形和无脑畸形是否是相关的表型;以及哪些遗传环境因素可能会改变IMP 1敲除动物的异常神经形成，导致无脑畸形，这是人类常见的先天性脑缺陷。目标2.阐明IMP 1基因在体内调控的分子通路。使用分子信号传导测定，检查特定标记物和转录效应物的时空表达，我们将确定IMP 1缺陷动物中的分子改变是否与正常神经形成所必需的信号传导受损的动物中发现的分子改变相似，以及IMP 1是否与Wnt信号传导相互作用。目标3.确定IMP 1缺陷动物中程序性细胞死亡的调节是否受损。我们将确定IMP 1缺陷是否与大脑发育过程中程序性细胞死亡，分化和增殖过程中的缺陷有关。我们将确定IMP 1是否通过Wnt依赖性或独立途径对细胞凋亡的调节很重要。 公共卫生关系：对最近发现的多通道跨膜蛋白（IMPAS 1/IMP 1）的研究将有助于深入了解正常和异常脑发育以及程序性细胞死亡的调控机制。IMP 1蛋白的基因在结构上与阿尔茨海默病早老素相关。我们发现，在我们的初步数据，这种蛋白质可能是一个重要的调节器的形成神经管胚胎发生的基本事件。我们计划提供证据证明这种蛋白质在中枢神经系统发育和神经形成信号传导中的重要作用，如果被破坏，就会导致无脑畸形，这是人类最常见的先天性脑缺陷。