Mint Adaptor Proteins in APP Binding and Processing

项目概要： 淀粉样蛋白斑块由纤维状淀粉样蛋白（A）肽组成，在阿尔茨海默氏症中起着关键作用 疾病（AD）发病机制。已经确定，A？是通过连续的蛋白水解产生的。 淀粉样前体蛋白（APP）分别由<$-和<$-分泌酶。然而，细胞生物学和 控制神经元中A β产生所必需的APP运输的分子较少被定义。一个关键步骤 在A？代中，APP内吞作用是由位于 Mint是在调节APP中具有重要功能的衔接蛋白 内吞作用和A？产生。我们以前的研究表明，Mint衔接蛋白调节APP 通过直接结合APP的YENPTY内吞基序，从而影响蛋白水解， 证据表明，薄荷是上调，并发现在A ²斑块在死后 人类AD脑支持薄荷糖在AD发病机制中的作用。与这一发现一致，我们发现 这三种Mint蛋白中的任何一种蛋白的缺失都会降低衰老小鼠和小鼠的A？产量。 AD模型这些发现表明APP-Mint相互作用是一个潜在的关键治疗靶点 选择性地减少AD中的A？产生。然而，薄荷糖影响的潜在机制， APP结合和A？生产尚不清楚。因此，本研究提案的总体目标是： 了解APP结合和加工的Mint依赖性调节。在目标1中，我们将确定 APP运输的细胞生物学以及Mint如何对突触活动诱导的APP至关重要 内吞作用和A？产生。在目标2中，我们将研究扰动APP-Mint 1的影响 在体外和体内小鼠模型中，的识别 调节APP结合和A？产生的新方法将是一个重要的工具，可以导致 开发用于治疗AD的替代治疗策略。通过结构研究，我们 发现Mint 1的自抑制调节APP结合和加工;然而， Mint 1自身抑制的潜在机制以及这种调节在神经元中的生理相关性 不知道。在目标3中，我们将阐明Mint 1自身抑制的生物学机制。 调节APP结合。调节Mint 1结合的自抑制机制的详细描述 APP是探索其运营的关键路线的宝贵工具，也是未来 靶向治疗。拟议的研究将为理解APP-Mint提供新的见解 生物学和这项研究的成果预计将有很强的翻译影响。

PROJECT SUMMARY: Amyloid plaques, which consist of fibrillar amyloid-¿ (A¿) peptides, play a key role in Alzheimer's disease (AD) pathogenesis. It is well established that A¿ is generated by sequential proteolysis of the amyloid precursor protein (APP) by ¿- and ¿-secretases, respectively. However, the cell biology and molecules controlling APP trafficking essential for A¿ production in neurons are less defined. A key step in A¿ generation is APP endocytosis that is mediated by the YENPTY sequence located in the cytoplasmic region of APP. Mints are adaptor proteins that are functionally important in regulating APP endocytosis and A¿ production. We previously showed that the Mint adaptor proteins regulate APP endocytosis by directly binding to the YENPTY endocytic motif of APP, thereby influencing proteolytic processing of APP. The evidence that Mints are upregulated and found in A¿ plaques in postmortem human AD brains supports a role for Mints in AD pathogenesis. Consistent with this finding, we showed that loss of any one of the three Mint proteins decreases A¿ production in aging mice and mouse models of AD. These findings suggest that the APP-Mint interaction is a potential key therapeutic target to selectively reduce A¿ production in AD. However, the mechanisms underlying the effects of Mints on APP binding and A¿ production are unclear. Therefore, the overall goal of this research proposal is to understand Mint-dependent regulation of APP binding and processing. In Aim 1, we will determine the cell biology of APP trafficking and how Mints are essential for synaptic activity-induced APP endocytosis and A¿ production. In Aim 2, we will investigate the effects of perturbing the APP-Mint1 interaction to decrease A¿ production in both in vitro and in vivo mouse models. The identification of novel ways to modulate APP binding and A¿ production will be an important tool that can lead to the development of alternative therapeutic strategies for treating AD. Through our structural studies, we found that autoinhibition of Mint1 regulates APP binding and processing; however, the molecular mechanism underlying Mint1 autoinhibition and the physiological relevance of this regulation in neurons are not known. In Aim 3, we will elucidate the biological mechanisms underlying Mint1 autoinhibition in regulating APP binding. A detailed delineation of the autoinhibitory mechanism regulating Mint1 binding to APP is an invaluable tool in exploring the critical routes to which it operates and a platform for future targeted therapeutics. The proposed research will provide new insights into understanding APP-Mint biology and the outcomes of this research are expected to have strong translational implications.