pxy-tdif复杂的内部结构揭示了一个CLE肽受体对之间的识别机制

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      植物能达到惊人的生命力是因为它们能够在分生组织中借助干细胞持续重复的产生新的器官。这种增殖和组织细胞之间的平衡是主要是通过CLAVATA3 /胚乳周围的调节肽激素（CLE）来完成的。一个完全特征的CLE肽，cle41 / TDIF（管状分子分化抑制因子），在抑制管状分子分化和促进原形成层细胞增殖的功能以及在血管发育与木材形成过程中发挥着重要的作用。不过，TDIF或其他CLE肽通过它们各自的受体识别的机制，仍然是非常难以捉摸的。我们在这里报告TDIF的复杂的晶体结构和它的受体PXY，一个富含亮氨酸重复受体的激酶（lrr-rk）。我们的结构揭示了TDIF主要采用一个像“Ω”般的构象结合到PXY的结构域的LRR的内表面的。TDIF和PXY之间的互动主要是由TDIF的相对保守的氨基酸介导的。基于结构的序列比对表明，TDIF相互作用的情形在其他已知的CLE受体中也是类似的。我们的数据显示：通过它们的受体为CLE肽识别机制提供一个结构模板，给其他未知的CLE肽受体的识别机会。+ Y6 H% v7 ]" p0 C# _) {
细胞在线研究最前沿出版2016.4.8。
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$ ]6 ~4 Y) f0 eCell Res. 2016 Apr 8. doi: 10.1038/cr.2016.45. [Epub ahead of print]
$ ?8 G( n# m! }7 s! |Crystal structure of PXY-TDIF complex reveals a conserved recognition mechanism among CLE peptide-receptor pairs.
  F( H9 {9 `: wPlants can achieve amazing lifespans because of their continuous and repetitive formation of new organs by stem cells present within meristems. The balance between proliferation and differentiation of meristem cells is largely regulated by the CLAVATA3/ENDOSPERM SURROUNDING REGION (CLE) peptide hormones. One of the well-characterized CLE peptides, CLE41/TDIF (tracheary elements differentiation inhibitory factor), functions to suppress tracheary element differentiation and promote procambial cell proliferation, playing important roles in vascular development and wood formation. The recognition mechanisms of TDIF or other CLE peptides by their respective receptors, however, remain largely elusive. Here we report the crystal structure of TDIF in complex with its receptor PXY, a leucine-rich repeat receptor kinase (LRR-RK). Our structure reveals that TDIF mainly adopts an "Ω"-like conformation binding to the inner surface of the LRR domain of PXY. Interaction between TDIF and PXY is predominately mediated by the relatively conserved amino acids of TDIF. Structure-based sequence alignment showed that the TDIF-interacting motifs are also conserved among other known CLE receptors. Our data provide a structural template for understanding the recognition mechanism of CLE peptides by their receptors, offering an opportunity for the identification of receptors of other uncharacterized CLE peptides.Cell Research advance online publication 8 April 2016; doi:10.1038/cr.2016.45.
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1 N, b$ a9 B) h9 P/ P原文地址：http://www.ncbi.nlm.nih.gov/pubmed/27055373