Bir1 Is Required for the Tension Checkpoint
Bir1 Is Required for the Tension Checkpoint
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DOI：
10.1091/mbc.e08-07-0723
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发表时间：
2009-02-01
影响因子：
3.3
通讯作者：
Davis, Trisha N.
中科院分区：
文献类型：
--
作者：
Shimogawa, Michelle M.;Widlund, Per O.;Davis, Trisha N.
酿酒酵母染色体乘客蛋白Ipl 1（Aurora B）和Sli 15（INCENP）是张力检查点所需的，但第三个乘客Bir 1的作用是有争议的。我们已经分离出一个温度敏感的突变体（bir 1 -107）在必不可少的C-末端区域的Bir 1已知的是需要结合Sli 15。该等位基因揭示了Bir 1的检查点功能。突变体显示双向缺陷，缺乏张力的缺陷检查点反应，以及无法分离突变体动粒。当bir 1 -107突变体中Bir 1定位被破坏时，Ipl 1定位于异常病灶。因此，Bir 1的一个检查点作用是正确定位Ipl 1并允许着丝粒的分离。定量分析表明，染色体乘客共定位与着丝粒在G1，但定位之间的着丝粒是在紧张局势。Bir 1定位于着丝粒在mcd 1 -1突变体中在张力不存在的情况下保持。我们的研究结果表明，建立张力删除Ipl 1，Bir 1和Sli 15，和他们的动粒分离活动，从附近的动粒，并允许细胞进行通过张力检查点。
The Saccharomyces cerevisiae chromosomal passenger proteins Ipl1 (Aurora B) and Sli15 (INCENP) are required for the tension checkpoint, but the role of the third passenger, Bir1, is controversial. We have isolated a temperature-sensitive mutant (bir1-107) in the essential C-terminal region of Bir1 known to be required for binding to Sli15. This allele reveals a checkpoint function for Bir1. The mutant displays a biorientation defect, a defective checkpoint response to lack of tension, and an inability to detach mutant kinetochores. Ipl1 localizes to aberrant foci when Bir1 localization is disrupted in the bir1-107 mutant. Thus, one checkpoint role of Bir1 is to properly localize Ipl1 and allow detachment of kinetochores. Quantitative analysis indicates that the chromosomal passengers colocalize with kinetochores in G1 but localize between kinetochores that are under tension. Bir1 localization to kinetochores is maintained in an mcd1-1 mutant in the absence of tension. Our results suggest that the establishment of tension removes Ipl1, Bir1, and Sli15, and their kinetochore detachment activity, from the vicinity of kinetochores and allows cells to proceed through the tension checkpoint.