A 20S COMPLEX CONTAINING CDC27 AND CDC16 CATALYZES THE MITOSIS-SPECIFIC CONJUGATION OF UBIQUITIN TO CYCLIN-B
A 20S COMPLEX CONTAINING CDC27 AND CDC16 CATALYZES THE MITOSIS-SPECIFIC CONJUGATION OF UBIQUITIN TO CYCLIN-B
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DOI：
10.1016/0092-8674(95)90338-0
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发表时间：
1995-04-21
期刊：
影响因子：
64.5
通讯作者：
KIRSCHNER, MW
中科院分区：
文献类型：
--
作者：
KING, RW;PETERS, JM;KIRSCHNER, MW
细胞周期蛋白B在后期开始时通过一种泛素依赖性蛋白水解系统降解。我们对有丝分裂的非洲爪蟾卵提取物进行了分级分离，以确定这一过程所需的成分。我们发现UBC4和至少一种其他的泛素结合酶能够支持细胞周期蛋白B的泛素化。细胞周期蛋白泛素化的有丝分裂特异性由一个20S复合物决定，该复合物包含出芽酵母CDC16和CDC27的同源物。因为这些蛋白质是酵母和哺乳动物细胞后期所必需的，我们将这个复合物称为后期促进复合物（APC）。CDC27抗体可耗尽APC活性，而免疫纯化的CDC27复合物足以补充间期提取物或重组UBC4与泛素激活酶E1的混合物。这些结果表明，APC作为一种受调控的泛素 - 蛋白质连接酶发挥作用，在有丝分裂中靶向细胞周期蛋白B进行破坏。
Cyclin B is degraded at the onset of anaphase by a ubiquitin-dependent proteolytic system. We have fractionated mitotic Xenopus egg extracts to identify components required for this process. We find that UBC4 and at least one other ubiquitin-conjugating enzyme can support cyclin B ubiquitination. The mitotic specificity of cyclin ubiquitination is determined by a 20S complex that contains homologs of budding yeast CDC16 and CDC27. Because these proteins are required for anaphase in yeast and mammalian cells, we refer to this complex as the anaphase-promoting complex (APC). CDC27 antibodies deplete APC activity, while immunopurified CDC27 complexes are sufficient to complement either interphase extracts or a mixture of recombinant UBC4 and the ubiquitin-activating enzyme E1. These results suggest that APC functions as a regulated ubiquitin-protein ligase that targets cyclin B far destruction in mitosis.