在AB5亚酶细胞毒素中,它使细胞内膜网的伴侣BiP无活化
Adrienne W Paton1, Travis Beddoe, Cheleste M Thorpe
1School of Molecular and Biomedical Science, University of Adelaide, South Australia 5005, Australia. adrienne.paton@adelaide.edu.au
Nature
|October 7, 2006
概括
细菌毒素 - - 细菌毒素 - - 细菌细胞毒素 - - 通过裂解必不可少的内分泌网膜伴侣BiP/GRP78.8的细胞死亡来触发细胞死亡. 这种特殊的裂变破坏了正常的细胞功能,突出了细菌病变的新机制.
科学领域:
- 微生物学 微生物学
- 细胞生物学 细胞生物学
- 毒理学 毒理学 毒理学
背景情况:
- AB5毒素是细菌毒性因子,由酶性A子单元和细胞吸收介导的B子单元组成.
- 已知的AB5毒素包括Shiga,霍乱和百日咳毒素.
- 亚细胞毒素是最近发现的第四个AB5毒素家族,来自Shiga有毒原体Escherichia coli.
研究的目的:
- 阐明潜酶细胞毒素极端细胞毒性背后的机制.
- 为了确定细胞的特定目标和分离部位的亚基酶细胞毒素.
- 为了研究BiP/GRP78在亚酶细胞毒素诱导的细胞死亡中的作用.
主要方法:
- 亚酶细胞毒素A亚单元的结构研究.
- 采用BiP/GRP78作为基质的体外裂解试验.
- 局部定向的突变发生,以改变BiP标位.
- 基于细胞的测定以评估细胞毒性和保护.
主要成果:
- 亚酶细胞毒素在一个单一的部位特异性地切割了内分泌网膜伴侣BiP/GRP78.
- 结构分析揭示了A子单元中的一个深深的活性点裂,解释了基质特异性.
- 在BiP目标部位的单个氨基酸替代使其抵抗裂变.
- 耐受性BiP受保护细胞从亚酶细胞毒素的共同表达.
结论:
- BiP/GRP78通过亚基酶细胞毒素的裂变是其高细胞毒性的主要原因.
- 这代表了细菌毒素诱导细胞死亡的新机制,通过破坏内质网膜恒常性来诱导细胞死亡.
- 针对BiP/GRP78裂变提供了一个潜在的治疗干预策略,以对抗亚酶细胞毒素.
相关概念视频
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