Department of Molecular Bioscience, College of Biomedical Science, Kangwon National University, Chuncheon, Korea.
Critical Zone Frontier Research Laboratory, Kangwon National University, Chuncheon, Korea.
FEBS Lett. 2018 May;592(9):1565-1574. doi: 10.1002/1873-3468.13049. Epub 2018 Apr 24.
Histone H2B ubiquitination mediated by the Rad6/Bre1 complex is crucial for regulating the stability and reassembly of the nucleosome. To understand the regulatory mechanisms of H2B ubiquitination, we explored proteins related to the Rad6/Bre1 complex. Interestingly, we observed that the stability of Lge1, reported to be a cofactor of Bre1, is greatly reduced in the absence of Bre1. The stability of Lge1 did require the middle fragment of Bre1 containing a coiled-coil structure, but not its E3 ligase activity. Additionally, we found that Lge1 is involved in the 'writing' step of H2B ubiquitination. Our data suggest that Bre1 mediates H2B ubiquitination more precisely by maintaining the stability of Lge1 as well as through its role as a known E3 ligase.
由 Rad6/Bre1 复合物介导的组蛋白 H2B 泛素化对于调节核小体的稳定性和重新组装至关重要。为了了解 H2B 泛素化的调节机制，我们研究了与 Rad6/Bre1 复合物相关的蛋白质。有趣的是，我们观察到 Lge1 的稳定性大大降低，Lge1 被报道为 Bre1 的共因子，在没有 Bre1 的情况下。Lge1 的稳定性确实需要包含卷曲螺旋结构的 Bre1 的中间片段，但不需要其 E3 连接酶活性。此外，我们发现 Lge1 参与了 H2B 泛素化的“书写”步骤。我们的数据表明，Bre1 通过维持 Lge1 的稳定性以及作为已知的 E3 连接酶的作用，更精确地介导 H2B 泛素化。
