Molecular analysis of collagen binding by the human discoidin domain receptors, DDR1 and DDR2 - Identification of collagen binding sites in DDR2
Molecular analysis of collagen binding by the human discoidin domain receptors, DDR1 and DDR2 - Identification of collagen binding sites in DDR2
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DOI：
10.1074/jbc.m301370200
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发表时间：
2003-05-09
影响因子：
4.8
通讯作者：
Leitinger, B
中科院分区：
文献类型：
--
作者：
Leitinger, B
广泛表达的哺乳动物盘状结构域受体（DDRs），DDR 1和DDR2，在受体酪氨酸激酶中是独特的，因为它们被细胞外基质蛋白胶原激活。各种类型的胶原蛋白结合并激活DDR，但胶原蛋白识别的分子细节尚未得到很好的定义。在这项研究中，重组细胞外结构域的DDR 1和DDR2的生产，探索DDR-胶原结合的细节。在固相测定中，两种DDR均以高亲和力结合胶原I。DDR 1仅识别胶原I作为二聚体而不是作为单体构建体，表明在DDR 1-胶原相互作用中需要受体二聚化。DDRs在其胞外结构域中含有盘状蛋白同源结构域，并且DDR2的分离的盘状蛋白结构域以高亲和力结合胶原I。此外，DDR2的盘状结构域（而不是DDR 1的盘状结构域）足以进行跨膜受体信号传导。为了映射DDR2的盘状结构域内的胶原结合位点，创建了突变体构建体，其中DDR2中潜在的表面暴露的环被交换为功能上不相关的盘状结构域的相应环。发现DDR2盘状结构域内的三个空间相邻的表面环与分离的DDR2胞外结构域的胶原结合密切相关。此外，胶原蛋白依赖性受体激活也需要相同的环。可以得出结论，与DDR2盘状结构域的多肽链末端相对的环区域构成胶原识别位点。
The widely expressed mammalian discoidin domain receptors (DDRs), DDR1 and DDR2, are unique among receptor tyrosine kinases in that they are activated by the extracellular matrix protein collagen. Various collagen types bind to and activate the DDRs, but the molecular details of collagen recognition have not been well defined. In this study, recombinant extracellular domains of DDR1 and DDR2 were produced to explore DDR-collagen binding in detail. In solid phase assays, both DDRs bound collagen I with high affinity. DDR1 recognized collagen I only as a dimeric and not as a monomeric construct, indicating a requirement for receptor dimerization in the DDR1-collagen interaction. The DDRs contain a discoidin homology domain in their extracellular domains, and the isolated discoidin domain of DDR2 bound collagen I with high affinity. Furthermore, the discoidin domain of DDR2, but not of DDR1, was sufficient for transmembrane receptor signaling. To map the collagen binding site within the discoidin domain of DDR2, mutant constructs were created, in which potential surface-exposed loops in DDR2 were exchanged for the corresponding loops of functionally unrelated discoidin domains. Three spatially adjacent surface loops within the DDR2 discoidin domain were found to be critically involved in collagen binding of the isolated DDR2 extracellular domain. In addition, the same loops were required for collagen-dependent receptor activation. It is concluded that the loop region opposite to the polypeptide chain termini of the DDR2 discoidin domain constitutes the collagen recognition site.