Effects of S1 cleavage on the structure, surface export, and signaling activity of human Notch1 and Notch2.
Effects of S1 cleavage on the structure, surface export, and signaling activity of human Notch1 and Notch2.
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DOI：
10.1371/journal.pone.0006613
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发表时间：
2009-08-24
期刊：
影响因子：
3.7
通讯作者：
Blacklow SC
中科院分区：
文献类型：
--
作者：
Gordon WR;Vardar-Ulu D;L'Heureux S;Ashworth T;Malecki MJ;Sanchez-Irizarry C;McArthur DG;Histen G;Mitchell JL;Aster JC;Blacklow SC
Notch受体通常在成熟过程中被称为S1的细胞外位置的类似于furin的蛋白酶切割，产生非共价相关亚基的异源二聚体。S1位点位于受体的关键负调控区（NRR）内，该受体包含三个高度保守的Lin12/Notch重复序列和一个异二聚化结构域（HD），它们相互作用以防止在缺乏配体时过早信号传导。由于S1切割在Notch信号传导中的作用尚不清楚，我们研究了S1切割对人类Notch1和Notch2的结构、表面运输和配体介导的激活的影响，以及在人类白血病中发现的突变对Notch1的配体非依赖性激活的影响。与缺乏s1 -解理环的Notch1 NRR相比，furin解理后Notch1 NRR的x射线结构变化不大。同样，Notch2 HD结构域的核磁共振研究表明，含有S1位点的环可以被移除或切割，而不会引起其结构的实质性变化。然而，抗S1切割的Notch1和Notch2受体在表面传递和信号传导能力方面表现出意想不到的差异：S1抗性Notch1受体表现出表面表达减少（但可检测到）和配体介导的受体激活，而S1抗性Notch2受体完全能够进行细胞表面传递和配体激活。对S1切割的可变依赖也延伸到t - all相关的NRR突变，因为常见的1类突变在引入抗呋喃受体时表现出不依赖配体的激活的可变减少，而2类突变表现出增加的信号活性。S1切割对Notch1和Notch2的表面表达有明显的影响，但通常不是Notch蛋白生理或病理生理激活所必需的。这些发现与受体激活模型一致，其中配体结合或t - all相关突变导致NRR的构象改变，从而允许金属蛋白酶切割。
Notch receptors are normally cleaved during maturation by a furin-like protease at an extracellular site termed S1, creating a heterodimer of non-covalently associated subunits. The S1 site lies within a key negative regulatory region (NRR) of the receptor, which contains three highly conserved Lin12/Notch repeats and a heterodimerization domain (HD) that interact to prevent premature signaling in the absence of ligands. Because the role of S1 cleavage in Notch signaling remains unresolved, we investigated the effect of S1 cleavage on the structure, surface trafficking and ligand-mediated activation of human Notch1 and Notch2, as well as on ligand-independent activation of Notch1 by mutations found in human leukemia. The X-ray structure of the Notch1 NRR after furin cleavage shows little change when compared with that of an engineered Notch1 NRR lacking the S1-cleavage loop. Likewise, NMR studies of the Notch2 HD domain show that the loop containing the S1 site can be removed or cleaved without causing a substantial change in its structure. However, Notch1 and Notch2 receptors engineered to resist S1 cleavage exhibit unexpected differences in surface delivery and signaling competence: S1-resistant Notch1 receptors exhibit decreased, but detectable, surface expression and ligand-mediated receptor activation, whereas S1-resistant Notch2 receptors are fully competent for cell surface delivery and for activation by ligands. Variable dependence on S1 cleavage also extends to T-ALL-associated NRR mutations, as common class 1 mutations display variable decrements in ligand-independent activation when introduced into furin-resistant receptors, whereas a class 2 mutation exhibits increased signaling activity. S1 cleavage has distinct effects on the surface expression of Notch1 and Notch2, but is not generally required for physiologic or pathophysiologic activation of Notch proteins. These findings are consistent with models for receptor activation in which ligand-binding or T-ALL-associated mutations lead to conformational changes of the NRR that permit metalloprotease cleavage.
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DOI：
10.1083/jcb.200609014
发表时间：
2007-02-12
期刊：
The Journal of cell biology
影响因子：
--
作者：
Nichols JT;Miyamoto A;Olsen SL;D'Souza B;Yao C;Weinmaster G
通讯作者：
Weinmaster G
影响因子：
64.8
作者：
GREENWALD, I;SEYDOUX, G
通讯作者：
SEYDOUX, G
DOI：
10.1073/pnas.93.4.1683
发表时间：
1996-02-20
影响因子：
11.1
作者：
Kopan, R;Schroeter, EH;Nye, JS
通讯作者：
Nye, JS
影响因子：
5.3
作者：
Rand, MD;Grimm, LM;Aster, JC
通讯作者：
Aster, JC
影响因子：
64.5
作者：
Blaumueller, CM;Qi, HL;ArtavanisTsakonas, S
通讯作者：
ArtavanisTsakonas, S