Molecular interactions between desmosomal cadherins
Molecular interactions between desmosomal cadherins
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DOI：
10.1042/0264-6021:3620317
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发表时间：
2002-03-01
影响因子：
4.1
通讯作者：
Magee, AI
中科院分区：
文献类型：
--
作者：
Syed, SEH;Trinnaman, B;Magee, AI
桥粒柯林斯（Dscs）和桥粒芯糖蛋白（Dsgs）是参与桥粒细胞-细胞连接形成的细胞粘附分子，并且与经典钙粘蛋白如E-钙粘蛋白具有结构相似性。为了鉴定和提供关于2型亚型所显示的蛋白质-蛋白质相互作用的类型的定量信息，并研究Call在该过程中的作用，我们开发了大肠杆菌表达系统以产生含有前两个胞外结构域的重组蛋白，即Dsg 2（1-2）和Dsc 2（1-2）。分析超离心，化学交联，CID，荧光和BIAcore已被用来提供第一个直接证据的钙结合桥粒钙粘蛋白。这些研究表明，Dsc 2（1-2）不仅在溶液中表现出亲同相互作用，而且还可以与Dsg 2（1-2）形成亲异相互作用。另一方面，后者表现出更弱的同性恋关联。我们的研究结果进一步表明，嗜异性相互作用是Ca 2+依赖的，而嗜同性协会的Ca 2+依赖性不太清楚。我们的数据表明Dsc 2（1-2）的功能特性与经典钙粘蛋白的功能特性更相似，这与Dsc与经典钙粘蛋白的序列同源性比Dsg更高的观察结果一致。除了证实以前报道的转染研究的结论，这表明形成横向异源二聚体和同源二聚体，我们的研究结果还提供了直接的定量信息，这些相互作用的强度是必不可少的理解：粘附机制。
Desmocollins (Dscs) and desmogleins (Dsgs) are cell-adhesion molecules involved in the formation of desmosome cell-cell junctions and share structural similarities to classical cadherins such as E-cadherin. In order to identify and provide quantitative information on the types of protein-protein interactions displayed by the type 2 isoforms and investigate the role of Call in this process, we have developed an Escherichia coli expression system to generate recombinant proteins containing the first two extracellular domains, namely Dsg2(1-2) and Dsc2(1-2). Analytical ultracentrifugation, chemical cross-linking, CID, fluorescence and BIAcore have been used to provide the first direct evidence of Ca2+ binding to desmosomal cadherins. These studies suggest that Dsc2(1-2) not only exhibits homophilic interactions in solution, but can also form heterophilic interactions with Dsg2(1-2). The latter, on the other hand, shows much weaker homophilic association. Our results further demonstrate that heterophilic interactions are Ca2+-dependent, whereas the Ca2+-dependence of homophilic association is less clear. Our data indicate that the functional properties of Dsc2(1-2) are more similar to those of classical cadherins, consistent with the observation that Dsc shares a higher level of sequence homology with classical cadherins than does Dsg. In addition to corroborating the conclusions of previously reported transfection studies which suggest the formation of lateral heterodimers and homodimers, our results also provide direct quantitative information on the strength of these interactions which are essential for understanding: the adhesion mechanism.