Functional redundancy of GSK-3α and GSK-3β in Wnt/β-catenin signaling shown by using an allelic series of embryonic stem cell lines
Functional redundancy of GSK-3α and GSK-3β in Wnt/β-catenin signaling shown by using an allelic series of embryonic stem cell lines
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DOI：
10.1016/j.devcel.2007.04.001
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发表时间：
2007-06-01
影响因子：
11.8
通讯作者：
Woodgett, James R.
中科院分区：
文献类型：
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作者：
Doble, Bradley W.;Patel, Satish;Woodgett, James R.
在哺乳动物细胞中，糖原合成酶激酶-3（GSK-3）作为两种同源物GSK-3 α和GSK-3 β存在，它们由独立的基因编码，它们共享相似的激酶结构域，但在它们的末端有很大的不同。在这里，我们描述了一个等位基因系列的小鼠胚胎干细胞（ESC）系0-4个功能GSK-3等位基因的产生，并检查GSK-3亚型在Wnt/β-连环蛋白信号转导中的功能。在缺乏GSK-3 α或GSK-3 β的细胞中未检测到GSK-3蛋白水平或活性的代偿性上调，并且Wnt/β-连环蛋白信号传导正常。只有在缺乏三个或所有四个等位基因的细胞中，观察到对β-连环蛋白/TCF介导的转录的基因剂量效应。事实上，GSK-3 α/β双敲除ESC显示出过度活化的Wnt/β-连环蛋白信号传导，并且其分化能力严重受损，但可以通过功能性GSK-3的再表达而恢复正常。GSK-3的变阻调节突出了在研究GSK-3在哺乳动物系统中的功能时考虑两种同系物的贡献的重要性。
In mammalian cells, glycogen synthase kinase-3 (GSK-3) exists as two homologs, GSK-3 alpha and GSK-3 beta, encoded by independent genes, which share similar kinase domains but differ substantially in their termini. Here, we describe the generation of an allelic series of mouse embryonic stem cell (ESC) lines with 0-4 functional GSK-3 alleles and examine GSK-3-isoform function in Wnt/beta-catenin signaling. No compensatory upregulation in GSK-3 protein levels or activity was detected in cells lacking either GSK-3 alpha or GSK-3 beta, and Wnt/beta-catenin signaling was normal. Only in cells lacking three or all four of the alleles was a gene-dosage effect on beta-catenin/TCF-mediated transcription observed. Indeed, GSK-3 alpha/beta double-knockout ESCs displayed hyperactivated Wnt/beta-catenin signaling and were severely compromised in their ability to differentiate, but could be rescued to normality by re-expression of functional GSK-3. The rheostatic regulation of GSK-3 highlights the importance of considering the contributions of both homologs when studying GSK-3 functions in mammalian systems.