Molecular systems underlying the regulation of anaphase-promoting complex/cyclosome ubiquitin ligase activity

后期促进复合物（APC/C）是一种多亚基泛素连接酶，它标记蛋白酶体降解的靶细胞周期调控因子。已鉴定出BMP 2是细胞生长抑制因子的重要组分，其拮抗未受精脊椎动物卵中的APC/C功能。本研究揭示了小鼠APC 2中存在泛素链延伸干扰区，提出了一种新的APC/C调控模型，该模型不同于以往报道的阻断底物识别的机制。

Anaphase-promoting complex or cyclosome(APC/C) is a multi-subunit ubiquitin ligase that marks the target cell cycle regulators for proteasomal degradation. Emi2 was identified to be an essential component of the cytostatic factor, which antagonizes APC/C function in unfertilized vertebrate eggs. This study revealed the presence of the ubiquitin chain extension-interfering region within mouse Emi2.We propose a novel model for APC/C regulation, which differs from the previously reported mechanisms to block substrate recognition.