利用質譜分析的方法研究Cdc14調控細胞有絲分裂與胞質分裂的機制

Global analysis of Cdc14 dephosphorylation sites reveals essential regulatory role in mitosis and cytokinesis

高立(Li Kao)

指導教授 ： 鄧述諄

國立臺灣大學/醫學院/微生物學研究所/博士(2014年)

https://doi.org/10.6342/NTU.2014.00918

摘要

酵母菌的細胞週期調控已經被完全的研究岀其機制，而負責調控的磷酸酶Cdk1利用與不同的週期素結合，以在不同細胞週期時對不同的受質進行磷酸化，以利細胞完成細胞週期。
Cdc14已知會針對被Cdk1磷酸化的受質進行去磷酸化，並調控M phase的週期素的降解作用，以利細胞可以離開M phase進行下一個細胞週期，Cdc14 在這個調控中是一個必要的去磷酸酶，更是細胞負責調控離開M phase的FEAR (cdc fourteen early anaphase release) 及MEN (mitotic exit network)中不可或缺的一個酵素。而Cdc14主要的功能在於將Cdh1/APC/C complex去磷酸並活化，進而使得M phase的週期素降解。但其他與有絲分裂及細胞分裂由Cdc14調控的受質並不清楚。我們利用質譜分析的方法對酵母菌來進行系統分析以找出Cdc14所調控的受質與位點。利用質譜分析，我們找到了455個可能的受質共835個位點。
我們進一步發現Cdc14可對被Cdk1磷酸化的受質進行去磷酸化來參予調控細胞週期。Cdc14可以經由Smc4 S128的位點去磷酸化調控染色體縮合(condensation)及有絲分裂進行，及對Bud3 S1549 與T1566的位點去磷酸化而調控Clb2在細胞內的位置及胞質分裂的進行。這些結果讓我們對於Cdc14在調控細胞離開M phase 所扮演的角色有更進一步的了解。

關鍵字

Cdc14 ； 磷酸化 ； 有絲分裂 ； 細胞分裂 ； Smc4 ； Bud3

並列摘要

Degradation of the M phase cyclins triggers the exit from M phase. Cdc14 is the major phosphatase required for the exit of the M phase. One of the functions of Cdc14 is to dephosphorylate and activate the Cdh1/APC/C complex, resulting in the degradation of the M phase cyclins. However, other crucial targets of Cdc14 for mitosis and cytokinesis remain to be elucidated. Here we systematically analyzed the positions of dephosphorylation sites for the Cdc14 in the budding yeast Saccharomyces cerevisiae. Quantitative mass spectrometry identified a total of 835 dephosphorylation sites on 455 potential Cdc14 substrates in vivo.
We validated two candidates that phosphorylated by Cdk1 and dephosphorylated by Cdc14. Cdc14 promotes the process of chromosome condensation via regulated the phosphorylated status of Smc4 on S128, and affects the bud-neck localization of Clb2 via regulated the phosphorylated status of Bud3 on S1549 and T1566. From these results we discovered that Cdc14-mediated dephosphorylation of Smc4 and Bud3 is essential for proper mitosis and cytokinesis, respectively. These results provide insight into the Cdc14-mediated pathways for exiting of M phase.

並列關鍵字

Cdc14 ； phosphorylation ； mitosis ； cytokinesis ； Smc4 ； Bud3

參考文獻

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