Walker A, Gallagher J T
CRC Department of Medical Oncology, Christie Hospital NHS Trust, Manchester, U.K.
Biochem J. 1996 Aug 1;317 ( Pt 3)(Pt 3):871-7. doi: 10.1042/bj3170871.
Heparan sulphate (HS) is an abundant polysaccharide component of the pericellular domain and is found in most soft tissues and all adherent cells in culture. It interacts with a wide spectrum of proteins including polypeptide growth factors and glycoproteins of the extracellular matrix. These interactions might influence fundamental cellular activities such as adhesion, growth and migration. HS might therefore represent a highly adaptive mechanism by which cells respond to their environment. The present study shows that the interaction between fibroblast HS, metabolically labelled with [3H]glucosamine, and the C-terminal heparin-binding domain of human plasma fibronectin (HEPII), is determined by distinct regions of the polysaccharide chain. By using a very sensitive affinity-chromatography method and specific polysaccharide scission it was shown that the HEPII-binding regions of HS reside within sulphated domains that are resistant to degradation by heparinase III. In addition, optimal binding was achieved with specific heparinase III-resistant fragments of 14-16 monosaccharides in length. The affinity of HS for HEPII was significantly decreased when the polysaccharide was cleaved with heparinase I. Chondroitin sulphate and dermatan sulphate were poor competitive inhibitors of [3H]HS binding to HEPII whereas unlabelled HS and heparin gave a strong inhibitory activity, with heparin being the most potent inhibitor. These findings suggest that the interaction between HEPII and HS is specific and requires extended sequences of seven to eight N-sulphated disaccharides in which a proportion of the iduronate residues are sulphated at C-2. The results have important implications for the functions of HS in cell adhesion and migration.
硫酸乙酰肝素（HS）是细胞周围区域丰富的多糖成分，存在于大多数软组织以及培养的所有贴壁细胞中。它与多种蛋白质相互作用，包括多肽生长因子和细胞外基质的糖蛋白。这些相互作用可能会影响诸如黏附、生长和迁移等基本细胞活动。因此，HS可能代表了一种细胞对其环境做出反应的高度适应性机制。本研究表明，用[3H]葡糖胺进行代谢标记的成纤维细胞HS与人血浆纤连蛋白（HEPII）的C端肝素结合域之间的相互作用，由多糖链的不同区域决定。通过使用一种非常灵敏的亲和色谱方法和特定的多糖切割技术，结果表明HS的HEPII结合区域位于对肝素酶III降解具有抗性的硫酸化结构域内。此外，长度为14 - 16个单糖的特定肝素酶III抗性片段可实现最佳结合。当用肝素酶I切割多糖时，HS对HEPII的亲和力显著降低。硫酸软骨素和硫酸皮肤素是[3H]HS与HEPII结合的较弱竞争性抑制剂，而未标记的HS和肝素具有很强的抑制活性，其中肝素是最有效的抑制剂。这些发现表明HEPII与HS之间的相互作用是特异性的，需要七到八个N - 硫酸化二糖的延伸序列，其中一定比例的艾杜糖醛酸残基在C - 2位被硫酸化。这些结果对HS在细胞黏附和迁移中的功能具有重要意义。
