Division of Molecular and Cellular Biology, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan.
J Cell Sci. 2012 Aug 15;125(Pt 16):3713-22. doi: 10.1242/jcs.099572.
Mammalian tissues and organs are composed of different types of cells that adhere to each other homotypically (i.e. interactions between cells of the same cell type) or heterotypically (i.e. interactions between different cell types), forming a variety of cellular patterns, including mosaic patterns. At least three types of cell-cell adhesion have been observed: symmetric homotypic, asymmetric homotypic and heterotypic cell adhesions. Cadherins and nectins, which are known cell-cell adhesion molecules, mediate these cell adhesions. Cadherins comprise a family of more than 100 members, but they are primarily involved in homophilic trans-interactions (i.e. interactions between the same cadherin members) between opposing cells. By contrast, the nectin family comprises only four members, and these proteins form both homophilic and heterophilic trans-interactions (i.e. interactions between the same and different nectin members on opposing cells). In addition, heterophilic trans-interactions between nectins are much stronger than homophilic trans-interactions. Because of these unique properties, nectins have crucial roles in asymmetric homotypic cell-cell adhesion at neuronal synapses and in various types of heterotypic cell-cell adhesions. We summarize recent progress in our understanding of the biology of nectins and discuss their roles in heterotypic cell-cell adhesions, whose formation cannot be solely explained by the action of cadherins.
哺乳动物组织和器官由不同类型的细胞组成，这些细胞同质地（即相同细胞类型的细胞之间的相互作用）或异质地（即不同细胞类型之间的相互作用）黏附在一起，形成各种细胞模式，包括镶嵌模式。已经观察到至少三种类型的细胞-细胞黏附：对称同质型、非对称同质型和异质型细胞黏附。钙黏蛋白和 nectin 是已知的细胞-细胞黏附分子，介导这些细胞黏附。钙黏蛋白包含一个由 100 多个成员组成的家族，但它们主要参与相邻细胞之间的同型亲合性(trans-interactions)相互作用（即相同钙黏蛋白成员之间的相互作用）。相比之下，nectin 家族仅由四个成员组成，这些蛋白质形成同质和异质亲合性(trans-interactions)相互作用（即相邻细胞上相同和不同 nectin 成员之间的相互作用）。此外，nectin 之间的异质亲合性相互作用比同型亲合性相互作用强得多。由于这些独特的特性，nectin 在神经元突触的非对称同质型细胞-细胞黏附和各种异质型细胞-细胞黏附中发挥着至关重要的作用。我们总结了我们对 nectin 生物学的理解的最新进展，并讨论了它们在异质型细胞-细胞黏附中的作用，这些黏附的形成不能仅仅用钙黏蛋白的作用来解释。
