Franke W W, Koch P J, Schäfer S, Heid H W, Troyanovsky S M, Moll I, Moll R
Division of Cell Biology, German Cancer Research Center, Heidelberg, Federal Republic of Germany.
Princess Takamatsu Symp. 1994;24:14-27.
The cells of various normal and malignantly transformed tissues are connected by "adhering junctions"-plasma membrane domains characterized by close membrane-membrane contact, a dense cytoplasmic plaque and, in most cases, the attachment of cytoskeletal filaments. On the basis of their specific ultrastructural organization and molecular composition, three major types of intercellular adhering junctions can be distinguished: 1. Adherens junctions appear in different shapes and sizes (zonula adhaerens, fascia adh., punctum adh.) and contain the transmembrane glycoprotein E-cadherin. The cytoplasmic portion of E-cadherin forms complexes with alpha-, beta-, and gamma-catenin and plakoglobin which, together with other proteins such as vinculin and radicin, constitute a plaque at which actin microfilaments insert. 2. Desmosomes (maculae adhaerentes) are mostly isodiametric (diameters up to approximately 0.5 micron) membrane domains traversed by representatives of two types of desmosomal cadherins, the desmogleins (Dsg) and desmocollins (Dsc), whose cytoplasmic tails contribute to a dense plaque containing plakoglobin and desmoplakin I (with or without an alternative splice form, desmoplakin II) which anchor IFs. The specific Dsc and Dsg subtypes can differ in different cell types and up to three different human genes have so far been identified for each desmosomal cadherin. 3. Complexus adhaerentes are junctions of variable size and shape that occur in lymphatic endothelia. They have a desmoplakin- and plakoglobin-rich plaque, whose specific transmembrane proteins have not yet been fully elucidated but can include endothelial cadherin-5. In their most elaborate subform- the "syndesmos" connecting the retothelial cells of lymph node sinus-these junctions can occupy extended portions of the cell surface. The molecular arrangements in desmosomes and complexus adhaerentes have been studied to understand the assembly and disappearance of these structures. The diagnostic potential of their constituent proteins for cell typing in tumor diagnosis is emphasized, as is the role of transient junction dissociation during invasion and metastasis of carcinomas and the general importance of tumor cell interactions with the retothelial cell system in the formation of lymph node metastases.
各种正常组织和恶性转化组织的细胞通过“黏附连接”相连，黏附连接是一种质膜结构域，其特征为膜与膜紧密接触、细胞质致密斑，且在大多数情况下，细胞骨架丝附着于此。根据其特定的超微结构组织和分子组成，可区分出三种主要的细胞间黏附连接类型：1. 黏着连接呈现不同的形状和大小（带状黏着连接、片状黏着连接、点状黏着连接），并含有跨膜糖蛋白E-钙黏蛋白。E-钙黏蛋白的细胞质部分与α-、β-和γ-连环蛋白以及桥粒斑珠蛋白形成复合物，这些蛋白与诸如纽蛋白和根蛋白等其他蛋白质一起构成一个斑块，肌动蛋白微丝插入该斑块。2. 桥粒（黏着斑）大多为等径的（直径可达约0.5微米）膜结构域，有两种桥粒钙黏蛋白的代表分子穿过，即桥粒芯糖蛋白（Dsg）和桥粒胶蛋白（Dsc），它们的细胞质尾巴形成一个致密斑，其中含有桥粒斑珠蛋白和桥粒斑蛋白I（有或没有可变剪接形式桥粒斑蛋白II），这些蛋白锚定中间丝。特定的Dsc和Dsg亚型在不同细胞类型中可能不同，目前每种桥粒钙黏蛋白已鉴定出多达三种不同的人类基因。3. 紧密黏附连接是大小和形状各异的连接，出现在淋巴管内皮中。它们有一个富含桥粒斑蛋白和桥粒斑珠蛋白的斑块，其特定的跨膜蛋白尚未完全阐明，但可能包括内皮钙黏蛋白-5。在其最复杂的亚形式中，即连接淋巴结窦内皮细胞的“联合桥粒”，这些连接可占据细胞表面的延伸部分。人们对桥粒和紧密黏附连接中的分子排列进行了研究，以了解这些结构的组装和消失过程。强调了其组成蛋白在肿瘤诊断中用于细胞分型的诊断潜力，以及在癌侵袭和转移过程中瞬时连接解离的作用，以及肿瘤细胞与内皮细胞系统相互作用在淋巴结转移形成中的普遍重要性。
