复合SMG5-SMG6PIN域的形成对于NMD至关重要
Katharina Kurscheidt1, Sophie Theunissen2,3, Natalia Pasquali4
1Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Martinsried, Germany.
Nature communications
|February 19, 2026
概括
无意中介的mRNA衰变 (NMD) 涉及SMG5和SMG6.6等蛋白质因子. 它们的相互作用形成了一个复合PIN域 (cPIN),具有内核酶活性,对于降解向mRNA和调节基因表达至关重要.
科学领域:
- 分子生物学分子生物学
- 细胞生物学 细胞生物学
- 生物化学 生物化学
背景情况:
- 无意中介的mRNA衰变 (NMD) 是一种关键的监测途径,用于降解含有过早停止编码子的异常mRNA.
- 在NMD中,内核酶激活和调节的精确机制仍然不完全理解.
- 多种蛋白质因子协调促进NMD,但它们在基质降解中的特定作用正在研究中.
研究的目的:
- 阐明内核酶活性在无意中介mRNA衰变 (NMD) 中的结构和机制基础.
- 研究SMG5和SMG6相互作用在形成活性内核酶复合物的作用.
- 为NMD目标mRNAs有效降解提供分子解释.
主要方法:
- 利用结构预测来建模蛋白相互作用.
- 进行了体外生化分析,以评估内核酶活性.
- 进行了基于细胞的无意中介mRNA衰变 (NMD) 分析,以评估功能影响.
主要成果:
- SMG5和SMG6通过它们的PIN域相互作用,形成具有强大的内核酶活性的复合接口 (cPIN).
- 复制的SMG5-SMG6cPIN异构体表现出高的酶活性,SMG5完成了SMG6的活性和基质结合位点.
- 影响SMG5-SMG6相互作用接口,RNA结合或活性部位的突变显著降低了cPIN活性和细胞NMD受损.
结论:
- SMG5和SMG6的平行PIN域合作组装一个高度活跃的内核酶,这对NMD至关重要.
- 本研究提供了一个结构和机制框架,以了解SMG5-SMG6复合体如何推动高效的NMD介导的mRNA降解.
- 这些发现揭示了细胞质量控制关键途径内内核酶调节和激活的新机制.
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