MECHANISMS OF PROTEOGLYCAN/COLLAGEN INTERACTIONS

蛋白多糖-胶原相互作用在大多数脊椎动物中普遍存在 组织，并可能在细胞黏附、迁移和 细胞外基质(ECM)的组装和功能。尽管 细胞表面或分泌物之间结合的生物化学 蛋白多糖和胶原蛋白还不完全了解，主要是 它们相互作用的静电、非特定基础一直是 建议。然而，通过电子显微镜，这个实验室有 观察肝素与I型胶原特定区域的结合 单体和纤维，并使用亲和共电泳法显示 高亲和力的胶原结合域仅由一小部分 肝素分子的一部分。这些结果支持这一假设。 高亲和力肝素-I型胶原结合更多地依赖于 中唯一的、稀疏表示的结构域或序列 糖胺多聚糖和蛋白质，而不依赖于位点 静电相互作用。 为了验证上述假设，首先，胶原结合部位 将分离肝素及其丰度、大小、序列和 其他ECM分子的结合选择性将由以下因素决定 亲和电泳法(ACE)和其他生化方法。 第二，推测的I型胶原的肝素结合区将 通过研究肝素与a)的相互作用得到证实 重组I型胶原蛋白，其中D-期片段具有 被删除或插入多个副本，或在改变的位置， 和b)携带已知I型胶原蛋白的“迷你胶原蛋白”多肽 序列。最后，确定了肝素和肝素的相互作用区域。 I型胶原将在细胞与I型胶原的相互作用中进行测试 并与其他ECM分子结合。这些研究将定义 最丰富的细胞基质之一的生物化学和功能 相互作用，并有助于理解和治疗 癌症等疾病，涉及异常细胞黏附和 ECM内的迁移。

Proteoglycan-collagen interactions are ubiquitous in most vertebrate tissues and likely play key roles in cell adhesion, migration, and extracellular matrix (ECM)assembly and function. Although the biochemistry of the binding between the cell surface or secreted proteoglycans and collagens is incompletely understood, a primarily electrostatic, non-specific basis for their interactions has been proposed. However, by electron microscopy this laboratory has observed heparin binding to specific regions on type I collagen monomers and fibrils, and using affinity coelectrophoresis has shown that high affinity collagen-binding domains comprise only a small fraction of the heparin molecule. These results favor the hypothesis that high affinity heparin-type I collagen binding depends more upon unique, sparsely represented domains or sequences within the glycosaminoglycan and protein, than upon site-independent electrostatic interactions. To test the above hypothesis, first, the collagen-binding sites of heparin will be isolated and their abundance, size, sequence, and binding selectivity for other ECM molecules will be determined by affinity coelectrophoresis (ACE) and other biochemical approaches. Second, the putative heparin-binding regions of type I collagen will be confirmed by studying the interactions of heparin with a) recombinant type I collagens in which D-period segments have either been deleted or inserted in multiple copies, or in altered positions, and b) with "mini collagen" peptides carrying known type I collagen sequences. Last, the identified interactive domains of heparin and type I collagen will be tested in cell interactions with type i collagen and with other ECM molecules. These studies will define the biochemistry and function of one of the most abundant of cell-matrix interactions, and contribute to the understanding and treatment of diseases such as cancer which involve abnormal cell adhesion and migration within the ECM.