Interaction of SNF1 Protein Kinase with Its Activating Kinase Sak1
Interaction of SNF1 Protein Kinase with Its Activating Kinase Sak1
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DOI：
10.1128/ec.00291-10
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发表时间：
2011-03-01
期刊：
影响因子：
--
通讯作者：
Carlson, Marian
中科院分区：
文献类型：
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作者：
Liu, Yang;Xu, Xinjing;Carlson, Marian
酿酒酵母SNF 1蛋白激酶是SNF 1/AMP激活蛋白激酶（AMPK）家族的成员，由三种激酶Sak 1、Tos 3和Elm 1激活，它们响应于葡萄糖限制和其他应激而磷酸化Thr-210上的Snf 1催化亚基。Sak 1是主要的Snf 1激活激酶，与Snf 1形成复合物。在这里，我们研究了Sak 1与SNF 1的相互作用。我们报告说，Sak 1 coimmunopurifies与Snf 1催化亚基从葡萄糖充满和葡萄糖限制的文化提取物和相互作用发生独立的磷酸化状态的Snf 1 Thr-210，Snf 1催化活性，和其他SNF 1亚基。Sak 1与Snf 1激酶结构域相互作用，Sak 1激酶结构域C末端的非保守序列介导与Snf 1的相互作用，并增强Snf 1的磷酸化和活化。Sak 1C末端响应于葡萄糖消耗而被修饰，这取决于SNF 1活性。用Sak 1的C末端替换Elm 1（或Tos 3）的C末端增强了Elm 1激酶结构域与Snf 1相互作用并磷酸化Snf 1的能力。这些发现表明Sak 1的C末端赋予其作为主要Snf 1激活激酶的功能，并表明Sak 1与SNF 1的物理结合促进了对环境变化的反应。
The Saccharomyces cerevisiae SNF1 protein kinase, a member of the SNF1/AMP-activated protein kinase (AMPK) family, is activated by three kinases, Sak1, Tos3, and Elm1, which phosphorylate the Snf1 catalytic subunit on Thr-210 in response to glucose limitation and other stresses. Sak1 is the primary Snf1-activating kinase and is associated with Snf1 in a complex. Here we examine the interaction of Sak1 with SNF1. We report that Sak1 coimmunopurifies with the Snf1 catalytic subunit from extracts of both glucose-replete and glucose-limited cultures and that interaction occurs independently of the phosphorylation state of Snf1 Thr-210, Snf1 catalytic activity, and other SNF1 subunits. Sak1 interacts with the Snf1 kinase domain, and nonconserved sequences C terminal to the Sak1 kinase domain mediate interaction with Snf1 and augment the phosphorylation and activation of Snf1. The Sak1 C terminus is modified in response to glucose depletion, dependent on SNF1 activity. Replacement of the C terminus of Elm1 (or Tos3) with that of Sak1 enhanced the ability of the Elm1 kinase domain to interact with and phosphorylate Snf1. These findings indicate that the C terminus of Sak1 confers its function as the primary Snf1-activating kinase and suggest that the physical association of Sak1 with SNF1 facilitates responses to environmental change.