Roles of PS1 in y-secretase integrity and trafficking

PS1 在 y-分泌酶完整性和运输中的作用

• 批准号: 7018506
• 负责人: HONG WANG
• 金额: $ 5.2万
• 依托单位: ROCKEFELLER UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-02-08 至 2008-02-07
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7018506
• 关键词: Golgi apparatus; RNA interference; endocytosis; endopeptidases; endoplasmic reticulum; enzyme activity; enzyme inhibitors; gene mutation; postdoctoral investigator; presenilin; protein structure function; protein transport; tissue /cell culture

DESCRIPTION (provided by applicant): Genetic mutations in presenilins (PSs, PS1/PS2) account for the majority of early-onset familial Alzheimer's disease (FAD). PS is the putative catalytic component of gamma-secretase complex. Gamma-secretase mediates the intramembrane cleavage of amyloid precursor protein (APP) that generates pathogenic small peptide Abeta in Alzheimer's disease (AD). So far, PSs, Nicastrin (Net), Aph-1, and PEN-2 have been identified as its essential components. They are integral membrane proteins that are synthesized in ER and travel through the secretory pathway. PS1 has been shown to play roles in intracellular trafficking of gamma-secretase component Net. In my preliminary studies, I found that in the absence of PS, PEN-2 is retained in the ER with a shorter half-life, suggesting PS is required for the trafficking and stability of PEN-2, probably via physical interaction. Furthermore, certain gamma-secretase inhibitor treatment results in markedly increased cell surface bound PS1 and PEN-2, but not Net. This is the first time that highly selective potent gamma-secretase inhibitors has been shown to differentially affect the trafficking of gamma-secretase components. Since these gamma-secretase inhibitors have been shown to physically bind PS1,I hypothesized that their effect on the gamma-secretase components is mediated by PS1. Indeed, my preliminary data further demonstrated that the inhibitor-induced cell surface accumulation of PEN-2 depends on PS1. Based on these results, I propose that PS and its associated gamma-secretase activity are critical for maintaining the integrity and proper intracellular trafficking of the gamma-secretase complex. The objective of this proposal is therefore to test this hypothesis. The impact of altered PS1 function by PS1 mutation (Specific Aim1) on the integrity and trafficking property of gamma-secretase complex will be systemically examined. These studies will reveal the mechanism of the cellular perturbation underlying PS1 mutations, including which results in pathogenesis of AD. Furthermore, detailed analysis of how gamma-secretase inhibitors affect the trafficking of gamma-secretase components (Specific Aim 2), especially whether they have the same effect toward PS1 mutants (Specific Aim 3) should provide valuable information for drug design to slow and ultimately prevent AD.

描述(申请人提供)：早老素(PSS，PS1/PS2)的基因突变是早发性家族性阿尔茨海默病(FAD)的主要原因。PS可能是γ-分泌酶复合体的催化组分。在阿尔茨海默病(AD)中，γ-分泌酶介导淀粉样前体蛋白(APP)的膜内裂解，APP产生致病小肽Abeta。到目前为止，PSS、Net、APH-1和PEN-2已被确定为其基本成分。它们是在内质网中合成的完整的膜蛋白，通过分泌途径进行传递。PS1已被证明在伽马分泌酶组分Net的细胞内运输中发挥作用。在我的初步研究中，我发现在没有PS的情况下，PEN-2以较短的半衰期保留在内质网中，这表明PS对于PEN-2的运输和稳定性是必需的，可能是通过物理相互作用。此外，某些伽马分泌酶抑制剂处理导致细胞表面结合的PS1和PEN-2显著增加，但不是Net。这是第一次发现高选择性的高效伽玛分泌酶抑制剂对伽马分泌酶组分的转运有不同的影响。由于这些伽马分泌酶抑制剂已被证明与PS1物理结合，我假设它们对伽马分泌酶成分的影响是由PS1介导的。事实上，我的初步数据进一步表明，抑制剂诱导的PEN-2细胞表面堆积依赖于PS1。基于这些结果，我认为PS及其相关的伽马分泌酶活性对于维持伽玛分泌酶复合体的完整性和适当的细胞内运输至关重要。因此，这项提议的目标是检验这一假设。系统研究PS1突变引起的PS1功能改变(特异性Aim1)对γ-分泌酶复合体完整性和转运特性的影响。这些研究将揭示PS1突变背后的细胞扰动机制，包括导致AD发病的机制。此外，详细分析伽玛分泌酶抑制剂如何影响伽玛分泌酶组分的转运(特异性目标2)，特别是它们对PS1突变体(特异性目标3)是否具有相同的影响，将为药物设计提供有价值的信息，以减缓并最终预防AD。