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阿尔茨海默氏症突变性γ-分泌酶复合体会阻碍粉样蛋白β-的产生

Parnian Arafi¹, Sujan Devkota¹, Emily Williams²

¹Department of Medicinal Chemistry, University of Kansas, Lawrence, KS, USA.

bioRxiv : the preprint server for biology

|September 11, 2024

概括

在Presenilin-1 (PSEN1) 中的家族性阿尔茨海默病突变会阻断马分泌酶复合体. 这种停滞,而不是粉样β的产生,似乎在阿尔茨海默病模型中引发了突触退化.

科学领域:

神经科学是一个神经科学.
分子生物学分子生物学
遗传学遗传学是一个

背景情况:

粉样蛋白前体蛋白 (APP) 和 presenilin-1 (PSEN1) 的误解突变与早期家族性阿尔茨海默病 (FAD) 有关.
这些突变影响了γ-分泌酶复合体对粉样β (Aβ) 的产生,这是阿尔茨海默氏症病变的粉样假设的核心过程.
APP的γ-分泌酶蛋白解是一种过程性修剪机制,而不是单一的裂变事件.

研究的目的:

为了研究6个额外的PSEN1 FAD突变对APP由γ-分泌酶的蛋白质分解处理的影响.
为了确定FAD突变是否导致APP蛋白解的特定步骤中的缺陷.
检查停滞的γ-分泌酶基质/中间体复合体在FAD病变发生过程中的作用.

主要方法:

对六种PSEN1 FAD突变体的γ-分泌酶对APP基质的所有蛋白质分解事件的定量分析.
光终身成像显微镜 (FLIM) 在完整的细胞中可视化酶基质/中间复合物形成.
在FAD的*C. elegans*模型中评估突触退化.

主要成果:

分析的所有六种PSEN1 FAD突变都在多个APP处理步骤中表现出缺陷.
大多数突变导致停滞的γ-分泌酶-基质/中间体复合体,不论Aβ的生产.
F386S突变特别损害了Aβ丰富的细胞区域的修剪步骤,表明了明显的γ-分泌酶功能障碍机制.

结论:

与FAD相关的PSEN1突变导致停滞和稳定的γ-分泌酶基质和/或酶介质复合体.
这些停滞不前的复合体,而不是Aβ产物,可能是FAD的主要致病触发因素.
这些发现挑战了传统的粉样蛋白假设,强调了酶处理功能障碍在阿尔茨海默病中的作用.

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