SEL-10 is an inhibitor of notch signaling that targets notch for ubiquitin-mediated protein degradation
SEL-10 is an inhibitor of notch signaling that targets notch for ubiquitin-mediated protein degradation
复制标题
DOI：
10.1128/mcb.21.21.7403-7415.2001
复制
发表时间：
2001-11-01
影响因子：
5.3
通讯作者：
Kitajewski, J
中科院分区：
文献类型：
--
作者：
Wu, GY;Lyapina, S;Kitajewski, J
Notch受体及其配体在正常动物的发育和发病中起着重要作用。我们发现F-box/WD 40重复蛋白SEL-10通过靶向Notch受体的细胞内结构域进行泛素介导的蛋白质降解来负调节Notch受体活性。内源性SEL-10活性的阻断通过仅含有WD 40重复的显性负性形式的表达来完成。在Notch 1的情况下，这种阻断导致Notch信号的增加，该信号由Notch 1受体的活化形式或Jagged 1通过Notch 1诱导的信号刺激。显性负性SEL-10的表达导致Notch 1的细胞内结构域的稳定。Notch 4胞内结构域结合SEL-10，但其活性并不因显性负性SEL-10表达而增加。SEL-10通过WD 40重复序列结合Notch 4，并优先结合细胞中Notch 4的磷酸化形式。我们将SEL-10结合所必需的Notch 4区域映射到锚蛋白重复序列下游的C-末端区域。当Notch 4的C-末端片段在细胞中表达时，它是高度不稳定的，但可以通过显性阴性SEL-10的表达来稳定。Notch 1和Notch 4细胞内结构域在体外的泛素化依赖于SEL-10。虽然SEL-10与Notch 1和Notch 4的细胞内结构域相互作用，但这些蛋白质对SEL-10功能的干扰反应不同。因此，SEL-10的功能是促进Notch蛋白的泛素化;然而，这些蛋白的命运可能不同。
Notch receptors and their ligands play important roles in both normal animal development and pathogenesis. We show here that the F-box/WD40 repeat protein SEL-10 negatively regulates Notch receptor activity by targeting the intracellular domain of Notch receptors for ubiquitin-mediated protein degradation. Blocking of endogenous SEL-10 activity was done by expression of a dominant-negative form containing only the WD40 repeats. In the case of Notch1, this block leads to an increase in Notch signaling stimulated by either an activated form of the Notch1 receptor or Jagged1-induced signaling through Notch1. Expression of:dominant-negative SEL-10 leads to stabilization of the intracellular domain of Notch1. The Notch4 intracellular domain bound to SEL-10, but its activity was not increased as a result of dominant-negative SEL-10 expression. SEL-10 bound Notch4 via the WD40 repeats and bound preferentially to a phosphorylated form of Notch4 in cells. We mapped the region of Notch4 essential for SEL-10 binding to the C-terminal region downstream of the ankyrin repeats. When this C-terminal fragment of Notch4 was expressed in cells, it was highly labile but could be stabilized by the expression of dominant-negative SEL-10. Ubiquitination of Notch1 and Notch4 intracellular domains in vitro was dependent on SEL-10. Although SEL-10 interacts with the intracellular domains of both Notch1 and Notch4, these proteins respond differently to interference with SEL-10 function. Thus, SEL-10 functions to promote the ubiquitination of Notch proteins; however, the fates of these proteins may differ.