Naturwissenschaftliches und Medizinisches Institut an der Universität Tübingen, Markwiesenstr. 55, 72770 Reutlingen, Germany.
Neurochem Res. 2013 Jun;38(6):1092-9. doi: 10.1007/s11064-012-0888-9. Epub 2012 Oct 9.
To perform their diverse biological functions the adhesion activities of the cell adhesion molecules of the immunoglobulin superfamily (IgCAMs) might be regulated by local clustering, proteolytical shedding of their ectodomains or rapid recycling to and from the plasma membrane. Another form of regulation of adhesion might be obtained through flexible ectodomains of IgCAMs which adopt distinct conformations and which in turn modulate their adhesion activity. Here, we discuss variations in the conformation of the extracellular domains of CEACAM1 and CAR that might influence their binding and signaling activities. Furthermore, we concentrate on alternative splicing of single domains and short segments in the extracellular regions of L1 subfamily members that might affect the organization of the N-terminal located Ig-like domains. In particular, we discuss variations of the linker sequence between Ig-like domains 2 and 3 (D2 and D3) that is required for the horseshoe conformation.
为了发挥其多样化的生物学功能，免疫球蛋白超家族（IgCAMs）的细胞黏附分子的黏附活性可能受到局部聚集、其细胞外结构域的蛋白水解脱落或快速从质膜循环到质膜的调节。黏附的另一种调节形式可能通过 IgCAMs 的柔性细胞外结构域来实现，这些结构域采用不同的构象，进而调节其黏附活性。在这里，我们讨论了 CEACAM1 和 CAR 的细胞外结构域构象的变化，这些变化可能影响它们的结合和信号转导活性。此外，我们还集中讨论了 L1 亚家族成员细胞外区单结构域和短片段的选择性剪接，这些变化可能影响位于 N 端的 Ig 样结构域的组织。特别是，我们讨论了 Ig 样结构域 2 和 3（D2 和 D3）之间的连接序列的变化，这是马蹄形构象所必需的。
