The COMA complex interacts with Cse4 and positions Sli15/Ipl1 at the budding yeast inner kinetochore
The COMA complex interacts with Cse4 and positions Sli15/Ipl1 at the budding yeast inner kinetochore
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DOI：
10.7554/elife.42879
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发表时间：
2019-05-21
期刊：
影响因子：
7.7
通讯作者：
Herzog, Franz
中科院分区：
文献类型：
--
作者：
Fischboeck-Halwachs, Josef;Singh, Sylvia;Herzog, Franz
着丝粒是位于着丝粒上的大分子蛋白质复合物，通过将染色体附着在纺锤体微管上并整合保护机制来确保染色体的准确分离。内动粒组装在CENP-A核小体上，并参与建立极光B激酶的动粒相关库，极光激酶是染色体乘客复合体（CPC）亚基，对染色体双定向至关重要。通过进行交联引导的芽殖酵母动粒复合物的体外重建，我们表明，与Ctf 19/Mcm 21（CENP-P/O）形成COMA复合物的Ame 1/Okp 1（CENP-U/Q）异二聚体通过Cse 4 N-末端选择性地结合Cse 4（CENP-A）核小体。Sli 15/Ipl 1（INCENP/Aurora-B）core-CPC通过Ctf 19 C-末端与COMA在体外相互作用，Ctf 19 C-末端的缺失影响Sli 15野生型细胞中的染色体分离保真度。在Sli 15着丝粒靶向缺陷突变体中，将Sli 15拴系到Ame 1/Okp 1拯救了Ctf 19耗尽后的合成致死性。这项研究显示了点着丝粒动粒结构的分子特征，并表明Ctf 19 C-末端在介导CPC结合和准确的染色体分离中的作用。
Kinetochores are macromolecular protein complexes at centromeres that ensure accurate chromosome segregation by attaching chromosomes to spindle microtubules and integrating safeguard mechanisms. The inner kinetochore is assembled on CENP-A nucleosomes and has been implicated in establishing a kinetochore-associated pool of Aurora B kinase, a chromosomal passenger complex (CPC) subunit, which is essential for chromosome biorientation. By performing crosslink-guided in vitro reconstitution of budding yeast kinetochore complexes we showed that the Ame1/Okp1(CENP-U/Q) heterodimer, which forms the COMA complex with Ctf19/Mcm21(CENP-P/O), selectively bound Cse4(CENP-A) nucleosomes through the Cse4 N-terminus. The Sli15/Ipl1(INCENP/Aurora-B) core-CPC interacted with COMA in vitro through the Ctf19 C-terminus whose deletion affected chromosome segregation fidelity in Sli15 wild-type cells. Tethering Sli15 to Ame1/Okp1 rescued synthetic lethality upon Ctf19 depletion in a Sli15 centromere-targeting deficient mutant. This study shows molecular characteristics of the point-centromere kinetochore architecture and suggests a role for the Ctf19 C-terminus in mediating CPC-binding and accurate chromosome segregation.