在ER中,虚无蛋白质折叠周期由未折叠的蛋白质O-曼诺基化通路终止
Chengchao Xu1, Songyu Wang, Guillaume Thibault
1Temasek Life Sciences Laboratory, National University of Singapore, Singapore.
概括
通过O-mannosylation,一种糖的修饰,可以终止内质网膜 (ER) 中的蛋白质折叠. 这一过程防止错误折叠的蛋白质消耗细胞资源,并促进它们的降解.
科学领域:
- 生物化学 生物化学
- 细胞生物学 细胞生物学
- 分子生物学分子生物学
背景情况:
- 新合成的多需要蛋白质陪伴者来进行适当的折叠和组装.
- 失败的折叠尝试导致基质降解,但长期循环在内质网膜 (ER) 中是有害的.
- ER压力可能来自积累的错误折叠的蛋白质,消耗细胞资源和增加反应性氧物种.
研究的目的:
- 为了研究失败的蛋白质折叠尝试在ER中被终止的机制.
- 识别特定的细胞过程,防止长时间的基质循环和降解.
- 阐明翻译后修改在蛋白质折叠质量控制中的作用.
主要方法:
- 用了开花酵母作为模型生物.
- 在体外蛋白质再折叠试验中使用.
- 研究了Pmt1/Pmt2复合体在O-mannosylation中的功能.
- 分析了O-mannosylated基质和Kar2陪伴者之间的相互作用.
主要成果:
- 发现Pmt1/Pmt2复合体对未折叠的蛋白质进行O-mannosylation,从而终止了发芽酵母失败的折叠尝试.
- 证明O-mannosylation无法逆转地使基质蛋白质的折叠潜力失效.
- 表明O-mannosylation减少了基质与Kar2伴侣的接触,促进了从折叠周期中去除.
- 证实这种修改可以防止长时间的基质循环,从而节约细胞资源.
结论:
- 蛋白质折叠的终止可以通过共价糖化事件,特别是O-曼诺基化实现.
- 在ER中,O-mannosylation作为一种关键的质量控制机制,可以防止长时间的蛋白质折叠尝试的有害影响.
- 这项研究揭示了糖化在调节蛋白质平衡和预防细胞压力的新作用.
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