Molecular Structure and Dimeric Organization of the Notch Extracellular Domain as Revealed by Electron Microscopy
Molecular Structure and Dimeric Organization of the Notch Extracellular Domain as Revealed by Electron Microscopy
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DOI：
10.1371/journal.pone.0010532
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发表时间：
2010-05-07
期刊：
影响因子：
3.7
通讯作者：
Walz, Thomas
中科院分区：
文献类型：
--
作者：
Kelly, Deborah F.;Lake, Robert J.;Walz, Thomas
背景：Notch受体将一个细胞的细胞命运决定与邻近细胞的决定联系在一起。在人类中，Notch信号的故障会导致疾病和先天性疾病。结构信息对于深入了解受体的机制以及潜在地干扰其用于治疗目的的功能是必不可少的。方法/主要发现：我们使用亲和网格方法制备了适合于电子显微镜和三维图像重建分析的果蝇Notch和人类Notch1受体的Notch细胞外域(NECD)样本。由此产生的3D密度图显示，NECD结构在不同物种之间是保守的。我们发现NECD形成二聚体，并采用不同的尚未定义的构象，我们确定了受体的膜-近端区域及其配体结合位置。结论/意义：我们的结果为NECD形成二聚体提供了直接和明确的证据。我们的研究进一步表明，NECD至少有三种不同的构象，可能与受体的不同功能状态有关。这些发现为现在将NECD的突变与其寡聚体状态和构象联系起来开辟了道路。
Background: The Notch receptor links cell fate decisions of one cell to that of the immediate cellular neighbor. In humans, malfunction of Notch signaling results in diseases and congenital disorders. Structural information is essential for gaining insight into the mechanism of the receptor as well as for potentially interfering with its function for therapeutic purposes.Methodology/Principal Findings: We used the Affinity Grid approach to prepare specimens of the Notch extracellular domain (NECD) of the Drosophila Notch and human Notch1 receptors suitable for analysis by electron microscopy and three-dimensional (3D) image reconstruction. The resulting 3D density maps reveal that the NECD structure is conserved across species. We show that the NECD forms a dimer and adopts different yet defined conformations, and we identify the membrane-proximal region of the receptor and its ligand-binding site.Conclusions/Significance: Our results provide direct and unambiguous evidence that the NECD forms a dimer. Our studies further show that the NECD adopts at least three distinct conformations that are likely related to different functional states of the receptor. These findings open the way to now correlate mutations in the NECD with its oligomeric state and conformation.