Regulation of Saccharomyces cerevisiae CDC7 function during the cell cycle.
Regulation of Saccharomyces cerevisiae CDC7 function during the cell cycle.
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酿酒酵母 CDC7 在细胞周期中功能的调节。
DOI：
10.1091/mbc.4.2.195
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发表时间：
1993
影响因子：
3.3
通讯作者：
Campbell,JL
中科院分区：
文献类型：
--
作者：
Yoon,HJ;Loo,S;Campbell,JL
酵母Cdc 7功能是G1/S转换所需的，并且依赖于通过START，这是由Cdc 28/cdc 2/p34蛋白激酶控制的点。CDC 7编码蛋白激酶活性，我们现在表明，这种激酶活性在细胞周期中变化，但蛋白水平似乎保持不变。我们提出了几条证据表明，周期性激活的CDC 7激酶至少部分是通过磷酸化。首先，Cdc 7蛋白的激酶活性通过在体外用磷酸酶使蛋白脱磷酸化而被破坏。第二，Cdc 7蛋白是低磷酸化和失活的激酶在提取物中的细胞停滞在START，但成为积极的和最大磷酸化后通过START。Cdc 7蛋白磷酸化模式复杂。磷酸肽图谱揭示了从异步酵母细胞制备的Cdc 7中的四个磷酸肽。自磷酸化和反式磷酸化似乎都有助于这种模式。自磷酸化显示发生通过使用热不稳定的Cdc 7蛋白。酵母提取物中的一种蛋白质可以磷酸化并激活大肠杆菌中产生的Cdc 7蛋白，而磷酸化在cdc 28突变体提取物中是不耐热的。Cdc 7蛋白携带的丝氨酸丙氨酸的变化，在共识识别位点Cdc 28激酶显示改变磷酸肽图，这表明该网站是重要的，在确定整体Cdc 7磷酸化模式。
The yeast Cdc7 function is required for the G1/S transition and is dependent on passage through START, a point controlled by the Cdc28/cdc2/p34 protein kinase. CDC7 encodes a protein kinase activity, and we now show that this kinase activity varies in the cell cycle but that protein levels appear to remain constant. We present several lines of evidence that periodic activation of CDC7 kinase is at least in part through phosphorylation. First, the kinase activity of the Cdc7 protein is destroyed by dephosphorylation of the protein in vitro with phosphatase. Second, Cdc7 protein is hypophosphorylated and inactive as a kinase in extracts of cells arrested at START but becomes active and maximally phosphorylated subsequent to passage through START. The phosphorylation pattern of Cdc7 protein is complex. Phosphopeptide mapping reveals four phosphopeptides in Cdc7 prepared from asynchronous yeast cells. Both autophosphorylation and phosphorylation in trans appear to contribute to this pattern. Autophosphorylation is shown to occur by using a thermolabile Cdc7 protein. A protein in yeast extracts can phosphorylate and activate Cdc7 protein made in Escherichia coli, and phosphorylation is thermolabile in cdc28 mutant extracts. Cdc7 protein carrying a serine to alanine change in the consensus recognition site for Cdc28 kinase shows an altered phosphopeptide map, suggesting that this site is important in determining the overall Cdc7 phosphorylation pattern.