Two ubiquitin ligases, APC/C-Cdh1 and SKP1-CUL1-F (SCF)-β-TrCP, sequentially regulate glycolysis during the cell cycle
Two ubiquitin ligases, APC/C-Cdh1 and SKP1-CUL1-F (SCF)-β-TrCP, sequentially regulate glycolysis during the cell cycle
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DOI：
10.1073/pnas.1102247108
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发表时间：
2011-03
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影响因子：
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通讯作者：
Slavica Tudzarova;S. Colombo;K. Stoeber;Saul Carcamo;G. Williams;S. Moncada
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作者：
Slavica Tudzarova;S. Colombo;K. Stoeber;Saul Carcamo;G. Williams;S. Moncada
在细胞增殖过程中，糖酵解促进酶6-磷酸果糖-2-激酶/果糖-2，6-二磷酸酶亚型3（PFKFB 3）的丰度由泛素连接酶APC/C-Cdh 1通过KEN盒控制。我们现在在同步化的HeLa细胞中证明，出现在G1中期至晚期的PFKFB 3对细胞分裂是必不可少的，因为它的沉默阻止了细胞进入S期。在葡萄糖剥夺阻滞的细胞中，只有当PFKFB 3存在或被下游糖酵解酶6-磷酸果糖-1-激酶取代时，葡萄糖替代后才发生S期进展。PFKFB 3在G1/S晚期停止检测，尽管没有Cdh 1;这种消失是通过蛋白酶体抑制来防止的。PFKFB 3含有DSG盒，因此是SCF-β-TrCP的潜在底物，SCF-β-TrCP是在S期有活性的泛素连接酶。在同步HeLa细胞转染PFKFB 3突变的KEN框，DSG框，或两者，我们建立了分解途径的酶在细胞周期的不同阶段和点，在糖酵解增强。因此，PFKFB 3的存在受到严格控制，以确保在G1的特定点上调糖酵解。我们认为糖酵解及其相关事件的上调代表了哺乳动物细胞中营养敏感的限制点。
During cell proliferation, the abundance of the glycolysis-promoting enzyme, 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase, isoform 3 (PFKFB3), is controlled by the ubiquitin ligase APC/C-Cdh1 via a KEN box. We now demonstrate in synchronized HeLa cells that PFKFB3, which appears in mid-to-late G1, is essential for cell division because its silencing prevents progression into S phase. In cells arrested by glucose deprivation, progression into S phase after replacement of glucose occurs only when PFKFB3 is present or is substituted by the downstream glycolytic enzyme 6-phosphofructo-1-kinase. PFKFB3 ceases to be detectable during late G1/S despite the absence of Cdh1; this disappearance is prevented by proteasomal inhibition. PFKFB3 contains a DSG box and is therefore a potential substrate for SCF-β-TrCP, a ubiquitin ligase active during S phase. In synchronized HeLa cells transfected with PFKFB3 mutated in the KEN box, the DSG box, or both, we established the breakdown routes of the enzyme at different stages of the cell cycle and the point at which glycolysis is enhanced. Thus, the presence of PFKFB3 is tightly controlled to ensure the up-regulation of glycolysis at a specific point in G1. We suggest that this up-regulation of glycolysis and its associated events represent the nutrient-sensitive restriction point in mammalian cells.