The spindle checkpoint of budding yeast depends on a tight complex between the Mad1 and Mad2 proteins
The spindle checkpoint of budding yeast depends on a tight complex between the Mad1 and Mad2 proteins
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DOI：
10.1091/mbc.10.8.2607
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发表时间：
1999-08-01
影响因子：
3.3
通讯作者：
Hardwick, KG
中科院分区：
文献类型：
--
作者：
Chen, RH;Brady, DM;Hardwick, KG
纺锤体检查点在有丝分裂纺锤体或染色体与纺锤体的连接存在缺陷时将细胞周期阻滞在中期。当纺锤体组装被破坏时，芽殖酵母mad和bub突变体不能停止并迅速失去活力。我们已经克隆了MAD 2基因，它编码一个196个氨基酸的蛋白质，在细胞周期中保持在一个恒定的水平，凝胶过滤和免疫共沉淀分析表明，Mad 2 p紧密关联的另一个纺锤体检查点组件，Mad 1 p。这种关联独立于细胞周期阶段和其他已知检查点蛋白的存在或不存在。此外，Mad 2 p与Mad 1 p的所有不同磷酸化同种型结合，这些同种型可以在SDS-PAGE上分辨。两种蛋白的缺失和突变分析表明，Mad 2 p与Mad 1 p的关联对于检查点功能和Mad 1 p的过度磷酸化至关重要。
The spindle checkpoint arrests the cell cycle at metaphase in the presence of defects in the mitotic spindle or in the attachment of chromosomes to the spindle. When spindle assembly is disrupted, the budding yeast mad and bub mutants fail to arrest and rapidly lose viability. We have cloned the MAD2 gene, which encodes a protein of 196 amino acids that remains at a constant level during the cell cycle, Gel filtration and co-immunoprecipitation analyses reveal that Mad2p tightly associates with another spindle checkpoint component, Mad1p. This association is independent of cell cycle stage and the presence or absence of other known checkpoint proteins. In addition, Mad2p binds to all of the different phosphorylated isoforms of Mad1p that can be resolved on SDS-PAGE. Deletion and mutational analysis of both proteins indicate that association of Mad2p with Mad1p is critical for checkpoint function and for hyperphosphorylation of Mad1p.