Dbf4-Cdc7 Phosphorylation of Mcm2 Is Required for Cell Growth
Dbf4-Cdc7 Phosphorylation of Mcm2 Is Required for Cell Growth
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DOI：
10.1074/jbc.m109.039123
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发表时间：
2009-10-16
影响因子：
4.8
通讯作者：
Kaplan, Daniel
中科院分区：
文献类型：
--
作者：
Bruck, Irina;Kaplan, Daniel
Dbf 4-Cdc 7激酶（DDK）是激活复制起点所必需的，并且DDK在体外使Mcm 2磷酸化。我们发现，芽殖酵母Cdc 7单独存在于溶液中作为一个弱活性的多聚体。Dbf 4与Cdc 7形成可能的异二聚体，并且该物种以显著更高的比活性磷酸化Mcm 2。Dbf 4单独与Mcm 2紧密结合，而Cdc 7单独与Mcm 2弱结合，表明Dbf 4招募Cdc 7使Mcm 2磷酸化。DDK磷酸化Mcm 2蛋白N末端附近的两个丝氨酸残基，Ser-164和Ser-170。mcm 2-S170 A的表达对缺乏内源性MCM 2（mcm 2 Delta）的酵母细胞是致死的;然而，这种致死性在含有DDK旁路突变体mcm 5-bob 1的细胞中被挽救。我们认为Mcm 2的DDK磷酸化是细胞生长所必需的。
The Dbf4-Cdc7 kinase (DDK) is required for the activation of the origins of replication, and DDK phosphorylates Mcm2 in vitro. We find that budding yeast Cdc7 alone exists in solution as a weakly active multimer. Dbf4 forms a likely heterodimer with Cdc7, and this species phosphorylates Mcm2 with substantially higher specific activity. Dbf4 alone binds tightly to Mcm2, whereas Cdc7 alone binds weakly to Mcm2, suggesting that Dbf4 recruits Cdc7 to phosphorylate Mcm2. DDK phosphorylates two serine residues of Mcm2 near the N terminus of the protein, Ser-164 and Ser-170. Expression of mcm2-S170A is lethal to yeast cells that lack endogenous MCM2 (mcm2 Delta); however, this lethality is rescued in cells harboring the DDK bypass mutant mcm5-bob1. We conclude thatDDKphosphorylation of Mcm2 is required for cell growth.