Fission yeast Mad3p is required for Mad2p to inhibit the anaphase-promoting complex and localizes to kinetochores in a Bub1p-, Bub3p-, and Mph1p-dependent manner
Fission yeast Mad3p is required for Mad2p to inhibit the anaphase-promoting complex and localizes to kinetochores in a Bub1p-, Bub3p-, and Mph1p-dependent manner
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DOI：
10.1128/mcb.22.8.2728-2742.2002
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发表时间：
2002-04-01
影响因子：
5.3
通讯作者：
Hardwick, KG
中科院分区：
文献类型：
--
作者：
Millband, DN;Hardwick, KG
纺锤体检查点延迟了响应纺锤体和动粒缺陷的中期到后期的转变。芽殖酵母的遗传筛选鉴定出Mad和Bub蛋白是这一保守调控途径的关键组分。在这里，我们提出了Mad 3 p的裂变酵母同源物。缺乏mad 3（+）的细胞在微管缺陷的情况下不能阻止其细胞周期。Mad 3 p共免疫沉淀Bub 3 p、Mad 2 p和纺锤体检查点效应子Slp 1/Cdc 20 p。我们证明，Mad 3 p的功能是必需的Mad 2 p的过度表达，导致中期逮捕。Mad 1 p、Bub 1 p和Bub 3 p不需要用于此逮捕。因此，Mad 3 p似乎在将抑制性“等待后期”信号转导至后期促进复合物（APC）中具有关键作用。Mad 3-绿色荧光蛋白（GFP）在有丝分裂早期被募集到未附着的动粒，并在延长的检查点激活后在那里积累。我们首次系统地研究了Mad 3/BubR 1蛋白募集对着丝粒的依赖性。我们发现Mad 3-GFP动粒定位依赖于Bub 1 p，Bub 3 p和Mph 1 p激酶，但不依赖于Mad 1 p或Mad 2 p。我们讨论的背景下，我们目前的理解纺锤体检查点功能的这些发现的影响。
The spindle checkpoint delays the metaphase-to-anaphase transition in response to spindle and kinetochore defects. Genetic screens in budding yeast identified the Mad and Bub proteins as key components of this conserved regulatory pathway. Here we present the fission yeast homologue of Mad3p. Cells devoid of mad3(+) are unable to arrest their cell cycle in the presence of microtubule defects. Mad3p coimmunoprecipitates Bub3p, Mad2p, and the spindle checkpoint effector Slp1/Cdc20p. We demonstrate that Mad3p function is required for the overexpression of Mad2p to result in a metaphase arrest. Mad1p, Bub1p, and Bub3p are not required for this arrest. Thus, Mad3p appears to have a crucial role in transducing the inhibitory "wait anaphase" signal to the anaphase-promoting complex (APC). Mad3-green fluorescent protein (GFP) is recruited to unattached kinetochores early in mitosis and accumulates there upon prolonged checkpoint activation. For the first time, we have systematically studied the dependency of Mad3/BubR1 protein recruitment to kinetochores. We find Mad3-GFP kinetochore localization to be dependent upon Bub1p, Bub3p, and the Mph1p kinase, but not upon Mad1p or Mad2p. We discuss the implications of these findings in the context of our current understanding of spindle checkpoint function.