在Saccharomyces cerevisiae酵母菌模式中,Bud3是否經由Cdk1調控而影響第二出芽位置選擇的方向

Cdk1-mediated Bud3 regulation of bud site selection in Saccharomyces cerevisiae

張嘉琴(Jia-Cin Jhang)

指導教授 ： 鄧述諄

國立臺灣大學/醫學院/微生物學研究所/碩士(2010年)

https://doi.org/10.6342/NTU.2010.02812

摘要

蛋白後修飾在生物細胞功能中扮演重要角色，後修飾包含有磷酸化、甲基化、乙醯化…等等，其中，磷酸化為目前研究最為透徹的後修飾作用。在酵母菌細胞中，Cdk1是最有力的激酶，在細胞週期中，Cdk1的活化需與不同的cyclin相互配合形成復合物，進而可磷酸化不同受質、甚至是受質的調控蛋白，進而影響整個酵母菌細胞週期，許多Cdk1的受質已經被報導出來，像是Sic1、Cln2、
Swi5…等。另外，要脫離一個細胞週期，則需要Cdc14酵素去磷酸化的作用，細胞走到M時期時，細胞染色體合成結束、分離後，就準備要脫離、進入下一個細胞週期，Cdc14從核仁釋出、移動至目標蛋白來進行去磷酸化的功能，像是與Sic1作用，因而可以減低Cdk1活性，使細胞準備好要脫離有絲分裂期。不同於Cdk1，很少的Cdc14受質被報導，因此我們有興趣知道是否有任何受質同時受到Cdk1及Cdc14兩種酵素的調控，進而影響到酵母菌的表現型。運用反向思考，我們分別收集野生型、溫度感知的Cdc14缺陷型酵母菌蛋白，並做分層處理，隨後針對磷酸化層的蛋白做質譜分析。從質譜分析得來的結果，相較於野生型，挑選出具有較高磷酸態的蛋白，進一步則是將之對比於Cdk1磷酸化的consensus sties，從其中篩選出一些候選蛋白。而BUD3是其中一個蛋白，我們將研究它是否真是同時受Cdk1及Cdc14調控的受質，並探討這樣的調控對酵母菌有任何功能影響。

關鍵字

第二出芽位置選擇 ； 蛋白後修飾

並列摘要

Cdc28 is well-known as the catalytic subunit of main cyclin- dependent kinase, whose activity associates with different substrates would drive events through cell cycle. Many substrates of Cdc28 have been reported, such as Sic1, Cln2, and Swi5…, etc. The protein phosphatase, Cdc14, required for mitotic exits. With anaphase onset, Cdc14 released from nucleolus by FEAR network and mitotic exit network, which enable a decrease in Cdk-Clb activity. Therefore, we wondered if there any unknown substrates of Cdc28 would be found. We had compared the phosphorylation level of proteins between wild type and cdc14 defective mutant strain by mass-spectrometry. After scoring, we got some candidates which have higher phosphorylation level in cdc14 mutant than wild type. The following steps are going to identify and characterize those candidates. BUD3 is one of the candidates from the Mass-data which is expressed close to the onset of mitosis and required for the axial pattern of cell division. It has shown that there are two sites located on the C-terminal possibly regulated by Cdc28 and Cdc14. We want to examine whether phosphorylation level of Bud3 control by Cdc28 and Cdc14. Then, we’ll going to perform both in vivo and in vitro assays to verify the relationship between Bud3, Cdc28 and Cdc14, and what events they’ll contribute to in the cell cycle of a budding yeast.

並列關鍵字

Cdk1 ； Cdc14 ； Bud3

參考文獻

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