结构性转变使得18型白蛋白的成熟和信号传递成为可能
Ying Dong1, Jeffrey P Bonin2, Pascal Devant3
1Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA; Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA.
Immunity
|May 11, 2024
概括
卡斯帕-1与卡斯帕-4不同地处理亲IL-18,利用其活性位点而不是外位点. 这种裂变对于激活IL-18至关重要.
科学领域:
- 分子生物学分子生物学
- 结构生物学是结构生物学.
- 免疫学 免疫学 免疫学
背景情况:
- 干白素-1 (IL-1) 家族成员,如IL-1β和IL-18,需要由炎酶相关的酶激活.
- 了解酶介导基质加工的分子机制对于理解炎症途径至关重要.
研究的目的:
- 阐明亲IL-18识别和通过caspase-1进行处理的结构基础.
- 为了比较caspase-1与亲IL-18的相互作用模式,与caspase-4与亲IL-18的相互作用模式进行比较.
- 为了研究pro-IL-18在caspase-1结合和裂变时的构造变化.
主要方法:
- 使用冷电子显微镜 (cryo-EM) 来确定caspase-1/pro-IL-18复合物的结构.
- 核磁共振 (NMR) 光谱学被用来研究apopro-IL-18的结构及其构造状态.
主要成果:
- 鉴定了caspase-1/pro-IL-18复合体的两个不同的构造:一个封闭的构造 (活性部位和外位相互作用) 和一个开放的构造 (仅活性部位相互作用).
- 卡斯巴-1的亲IL-18招募和处理显示出与外酸相比,对活性位点的依赖性更大,与卡斯巴-4不同.
- Apo pro-IL-18采用紧的折叠,在酶-1结合时保持,但在分裂后改变,显示成熟的IL-18的独特结构.
- 对于IL-18受体和IL-18结合蛋白的结合点仅在亲IL-18裂变后才形成,这表明需要构造变化.
结论:
- 结构研究揭示了caspase-1选择和处理亲IL-18.18的特定机制.
- 这些发现突出了在基质识别过程中,caspases对活性位点和外位点相互作用的差异性利用.
- 通过caspase-1的裂变被证明是诱导亲IL-18的结构变化的关键步骤,从而使其炎症活性和受体结合成为可能.
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