Wheeler G N, Parker A E, Thomas C L, Ataliotis P, Poynter D, Arnemann J, Rutman A J, Pidsley S C, Watt F M, Rees D A
National Institute for Medical Research, Mill Hill, London, United Kingdom.
Proc Natl Acad Sci U S A. 1991 Jun 1;88(11):4796-800. doi: 10.1073/pnas.88.11.4796.
Among the variety of specialized intercellular junctions, those of the adherens type have the most obvious association with cytoskeletal elements. This may be with the actin microfilament system as in the zonula adherens or with intermediate filaments as in the macula adherens, or desmosome. In the former case, it is clear that transmembrane glycoproteins of the cadherin family are important adhesive components of the molecular assembly. We now show for desmosomes that a major glycoprotein component (desmosomal glycoprotein DGI) has extensive homology with the cadherins, defining an extended family, but also has unique features in its cytoplasmic domain that are likely to be relevant to the association with intermediate rather than actin filaments. A novel 282-residue extension contains repeats of approximately 29 amino acid residues predicted to have an antiparallel beta-sheet structure, followed by a glycine-rich sequence. As in the cadherins, the extracellular domain contains possible Ca2(+)-binding sequences and a potential protease processing site. The cell adhesion recognition region (His-Ala-Val) of the cadherins is modified to Arg-Ala-Leu.
在各种特殊的细胞间连接中，黏附型连接与细胞骨架成分的联系最为明显。这可能是与黏着小带中的肌动蛋白微丝系统相关，或是与黏着斑（即桥粒）中的中间丝相关。在前一种情况下，很明显钙黏蛋白家族的跨膜糖蛋白是分子组装的重要黏附成分。我们现在发现，对于桥粒而言，一种主要的糖蛋白成分（桥粒糖蛋白DGI）与钙黏蛋白具有广泛的同源性，从而定义了一个扩展家族，但它在细胞质结构域也具有独特特征，这些特征可能与和中间丝而非肌动蛋白丝的关联有关。一个新的由282个残基组成的延伸序列包含预测具有反平行β折叠结构的约29个氨基酸残基的重复序列，随后是一个富含甘氨酸的序列。与钙黏蛋白一样，细胞外结构域包含可能的Ca2(+)结合序列和一个潜在的蛋白酶加工位点。钙黏蛋白的细胞黏附识别区域（His-Ala-Val）被修饰为Arg-Ala-Leu。
