在 presenilin-1 中需要两种跨膜亚斯巴酸盐,用于 presenilin 内蛋白解和玛分泌酶活性
M S Wolfe1, W Xia, B L Ostaszewski
1Center for Neurologic Diseases, Harvard Medical School and Brigham and Women's Hospital, Boston, Massachusetts 02115, USA. mwolfe@utmem.edu
Nature
|April 17, 1999
概括
presenilin-1 中的两个酸残留物对马分泌酶活性至关重要,这与阿尔茨海默病的发病有关. 影响这些阿斯巴酸盐的突变减少了粉样蛋白β的产生,为疾病机制提供了洞察力.
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
- 生物化学 生物化学
背景情况:
- 阿尔茨海默病的特点是大脑中粉样β (Abeta) 的积累.
- 马分泌酶从β-粉样蛋白前体蛋白中执行阿贝塔生成的最后一步.
- presenilin-1 (PS1) 和 presenilin-2 (PS2) 基因的突变是家族性阿尔茨海默病的常见原因,改变了马分泌酶的活性.
研究的目的:
- 调查Presenilin-1 (PS1) 中保存的酸残留物在玛分泌酶活性中的作用.
- 确定这些酸残留物中的突变对阿贝塔生产和PS1内蛋白解的影响.
主要方法:
- 在PS1中保存的阿斯巴酸盐残留物 (Asp 257和Asp 385) 的位点定向突变发生.
- 评估细胞系和无细胞显微体中的阿贝塔生产和β-粉样蛋白前体蛋白碳氧终端片段的水平.
- 在野生类型和突变PS1变种中分析PS1内分蛋白解.
主要成果:
- 在PS1中Asp 257或Asp 385的突变显著降低了阿贝塔的产量.
- 这些突变增加了β-粉样蛋白前体蛋白碎片的水平,这是玛分泌酶的基质.
- Asp突变还抑制了PS1的正常内蛋白解,这是TM6-TM7细胞质循环中发生的过程.
- 即使在与家族性阿尔茨海默氏症相关的PS1变异中,该变异绕过了正常的内蛋白质分解,Asp 385突变也抑制了玛分泌酶活性.
结论:
- 在PS1中的两种跨膜亚斯巴酸盐残留物对于PS1内蛋白解和玛分泌酶活性都至关重要.
- 这些发现表明PS1可以作为辅因子或作为阿斯巴提尔蛋白酶本身,调解玛分泌酶活性.
- 这项研究为马分泌酶的分子机制及其在阿尔茨海默病中的作用提供了关键的见解.
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