Functional interaction between SEL-10, an F-box protein, and the nuclear form of activated Notch1 receptor
Functional interaction between SEL-10, an F-box protein, and the nuclear form of activated Notch1 receptor
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DOI：
10.1074/jbc.m101343200
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发表时间：
2001-09-14
影响因子：
4.8
通讯作者：
Israël, A
中科院分区：
文献类型：
--
作者：
Gupta-Rossi, N;Le Bail, O;Israël, A
Notch信号通路在无脊椎动物和脊椎动物的许多细胞命运决定中是必不可少的。配体结合后，两步蛋白水解裂解释放受体的细胞内部分，其易位到细胞核并充当转录激活剂。虽然Notch诱导的基因转录已被广泛报道，但其内源性核形式很少被观察到。我们报告说，Notch 1的核内结构域是稳定的蛋白酶体抑制剂，是在体外的多聚泛素化的底物。SEL-10是Cdc 4家族的F-box蛋白，在秀丽隐杆线虫中Lin 12/Notch负调控因子的遗传筛选中分离。我们分离了SEL-10的人类和小鼠对应物，并研究了这种蛋白质的显性阴性形式（缺失F-box）对Notch 1稳定性和活性的作用。该分子可以稳定细胞内Notch 1并增强其转录活性，但对非活性膜锚定形式的受体没有影响。然后，我们证明SEL-10特异性地与Notch 1的核形式相互作用，并且这种相互作用需要磷酸化事件。综上所述，这些数据表明SEL-10参与关闭Notch信号转导的泛素-蛋白酶体介导的降解后，核磷酸化事件的活性转录因子。
The Notch signaling pathway is essential in many cell fate decisions in invertebrates as well as in vertebrates. After ligand binding, a two-step proteolytic cleavage releases the intracellular part of the receptor which translocates to the nucleus and acts as a transcriptional activator. Although Notch-induced transcription of genes has been reported extensively, its endogenous nuclear form has been seldom visualized. We report that the nuclear intracellular domain of Notch1 is stabilized by proteasome inhibitors and is a substrate for polyubiquitination in vitro. SEL-10, an F-box protein of the Cdc4 family, was isolated in a genetic screen for Lin12/Notch-negative regulators in Caenorhabditis elegans. We isolated human and murine counterparts of SEL-10 and investigated the role of a dominant-negative form of this protein, deleted of the F-box, on Notch1 stability and activity. This molecule could stabilize intracellular Notch1 and enhance its transcriptional activity but had no effect on inactive membrane-anchored forms of the receptor. We then demonstrated that SEL-10 specifically interacts with nuclear forms of Notch1 and that this interaction requires a phosphorylation event. Taken together, these data suggest that SEL-10 is involved in shutting off Notch signaling by ubiquitin-proteasome-mediated degradation of the Active transcriptional factor after a nuclear phosphorylation event.