Glucose-regulated interaction of a regulatory subunit of protein phosphatase 1 with the Snf1 protein kinase in Saccharomyces cerevisiae
Glucose-regulated interaction of a regulatory subunit of protein phosphatase 1 with the Snf1 protein kinase in Saccharomyces cerevisiae
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DOI：
10.1073/pnas.95.11.6245
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发表时间：
1998-05-26
影响因子：
11.1
通讯作者：
Carlson, M
中科院分区：
文献类型：
--
作者：
Ludin, K;Jiang, R;Carlson, M
Snf 1蛋白激酶家族在真核生物中是保守的。在酿酒酵母中，Snf 1对于葡萄糖抑制基因的转录响应葡萄糖饥饿是必不可少的。在激酶复合物中，Snf 1与其活化亚基Snf 4之间的直接相互作用受葡萄糖信号调节。葡萄糖对Snf 1-Snf 4相互作用的抑制依赖于蛋白磷酸酶1及其靶向亚基Reg 1。在这里，我们表明，Reg 1相互作用的Snf 1催化结构域的双杂交系统。这种相互作用增加响应葡萄糖限制，并需要保守的苏氨酸在激酶的激活环，一个假定的磷酸化位点。Reg 1的抑制作用似乎需要Snf 1调节结构域，因为当Snf 1功能由分离的催化结构域提供时，Reg 1 Delta突变不再缓解葡萄糖对转录的抑制。最后，我们发现，废除Snf 1的催化活性的ATP结合位点的突变引起升高，与Reg 1组成的相互作用，表明Snf 1负调节自己的相互作用与Reg 1。我们提出了一个模型，其中蛋白磷酸酶1，Reg 1为目标，促进构象变化的激酶复合物从其活性状态的自抑制状态。
The Snf1 protein kinase family has been conserved in eukaryotes. In the yeast Saccharomyces cerevisiae, Snf1 is essential for transcription of glucose-repressed genes in response to glucose starvation. The direct interaction between Snf1 and its activating subunit, Snf4, within the kinase complex is regulated by the glucose signal. Glucose inhibition of the Snf1-Snf4 interaction depends on protein phosphatase 1 and its targeting subunit, Reg1. Here we show that Reg1 interacts with the Snf1 catalytic domain in the two-hybrid system. This interaction increases in response to glucose limitation and requires the conserved threonine in the activation loop of the kinase, a putative phosphorylation site. The inhibitory effect of Reg1 appears to require the Snf1 regulatory domain because a reg1 Delta mutation no longer relieves glucose repression of transcription when Snf1 function is provided by the isolated catalytic domain. Finally, we show that abolishing the Snf1 catalytic activity by mutation of the ATP-binding site causes elevated, constitutive interaction with Reg1, indicating that Snf1 negatively regulates its own interaction with Reg1. We propose a model in which protein phosphatase 1, targeted by Reg1, facilitates the conformational change of the kinase complex from its active state to the autoinhibited state.