Arabidopsis E2Fc functions in cell division and is degraded by the ubiquitin-SCFAtSKP2 pathway in response to light
Arabidopsis E2Fc functions in cell division and is degraded by the ubiquitin-SCFAtSKP2 pathway in response to light
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DOI：
10.1105/tpc.006791
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发表时间：
2002-12-01
期刊：
影响因子：
11.6
通讯作者：
Gutierrez, C
中科院分区：
文献类型：
--
作者：
del Pozo, JC;Boniotti, MB;Gutierrez, C
通过细胞周期的选择性泛素介导的蛋白水解控制了几种细胞增殖蛋白的可用性，因此也控制了它们的活性。E2 F转录因子通过调节基因表达在细胞增殖和分化中发挥不同的作用。在这里，我们报告，拟南芥AtE 2Fc基因表达和泛素-蛋白酶体蛋白水解之间的平衡调节。AtE 2Fc降解涉及E3泛素连接酶Skp 1，Cullin，F-box（SCFAtSKP 2）复合物的功能，似乎依赖于细胞周期蛋白依赖性激酶磷酸化。此外，我们发现AtE 2Fc降解是由黑暗生长的幼苗的光刺激引发的。有趣的是，生长素反应突变体axr 1 -12，其中SCF组分CUL 1的RUB 1修饰受损，显示增加的AtE 2Fc蛋白水平，表明AtE 2Fc稳定性控制功能障碍。同样，AtE 2Fc蛋白的稳定形式的过表达负面地影响细胞分裂并增加细胞大小。这些作用至少部分是通过下调细胞周期基因AtCDC 6介导的。AtE 2 FC与植物视网膜母细胞瘤相关蛋白相互作用的事实进一步支持了AtE 2 FC在基因表达中的负面作用，这表明AtE 2 FC可能形成了阻遏物复合物的一部分。我们认为AtE 2Fc可能在细胞分裂和从skotomorphogenesis到photomorphogenesis的过渡过程中发挥作用。
Selective ubiquitin-mediated proteolysis through the cell cycle controls the availability, and therefore the activity, of several cell proliferation proteins. E2F transcription factors play distinct roles in both proliferating and differentiated cells by regulating gene expression. Here, we report that Arabidopsis AtE2Fc is regulated by a balance between gene expression and ubiquitin-proteasome proteolysis. AtE2Fc degradation implicates the function of the E3 ubiquitin-ligase Skp1, Cullin, F-box (SCFAtSKP2) complex and seems to be dependent on cyclin-dependent kinase phosphorylation. In addition, we found that AtE2Fc degradation is triggered by light stimulation of dark-grown seedlings. Interestingly, the auxin response mutant axr1-12, in which RUB1 modification of the SCF component CUL1 is impaired, shows increased AtE2Fc protein levels, suggesting a dysfunction in the control of AtE2Fc stability. Likewise, overexpression of a stable form of the AtE2Fc protein negatively affects cell division and increases cell size. These effects are mediated, at least in part, by downregulating the cell cycle gene AtCDC6. The negative role of AtE2Fc in gene expression is further supported by the fact that AtE2Fc interacts with plant retinoblastoma-related protein, suggesting that AtE2Fc might form part of a repressor complex. We propose that AtE2Fc might play a role in cell division and during the transition from skotomorphogenesis to photomorphogenesis.