Structure of type IV collagen-binding protein from mushroom Hypsizigus marmoreus and its inhibitory activity for cell adhesion

阐明癌细胞与细胞外基质成分相互作用的机制对于了解肿瘤转移和设计有效的预防方法具有重要意义。癌细胞粘附于内皮基底。膜在转移过程中尤其重要，并且抑制该步骤将有效抑制癌症转移。在寻找阻止癌细胞粘附于基底膜成分纤连蛋白和胶原的化合物的过程中，我们发现某些蘑菇的提取物可以抑制小鼠刘易斯肺癌细胞粘附于IV型胶原。本研究采用亲和层析法从真姬菇中分离纯化了23 kDa的Ⅳ型胶原结合蛋白HM-23。结果，我们发现HM-23抑制3LL细胞与IV型胶原的粘附。部分氨基酸序列 ...更多信息 已经发现HM-23与调节胶原原纤维形成的纤调蛋白具有同源性，并且HM-23是迄今未知的蛋白质。溴化氰降解HM-23产生两个分子量约为110 kDA的多肽，表明蛋氨酸存在于分子的中心。这些多肽的氨基酸测序表明，该甲硫氨酸残基是三个确定序列之一中所含的残基。抗HM-23抗体用于通过应用酶联免疫吸附测定来检查HM-23与细胞外基质蛋白之间的相互作用。结果表明，HM-23与I型胶原、IV型胶原和明胶以及纤连蛋白弱结合，但根本不与层粘连蛋白结合。除了这种蘑菇蛋白能与动物细胞外基质蛋白相互作用外，我们还发现米糠中含有纤维连接蛋白结合蛋白，这些关于非动物蛋白与动物细胞外基质蛋白相互作用的发现将开启广泛的生物学和细胞生物学兴趣，从而为包括癌症转移在内的问题提供答案。少

It is very important to elucidate the mechanism of interection between cancer cells and extracellular matrix components for understanding the cancer metastasis and designing the method useful for its prevention. The adhesion of cancer cells to the endothelial basement. membrane is especially important in the metastatic process, and the inhibition of this step would be effective to inhibit cancer metastasis. During search for the compounds which prevent the adhesion of cancer cells to the basement membrane components, fibronectin and collagen, we have found that the extracts from certain mushrooms can inhibit the adhesion of mouse Lewis lung carcinoma cells to type IV collagen. In the present study, we examined the characteristics of the 23kDa type IV collagen-binding protein (HM-23) which was isolated from mushroom Hypsizigus marmoreus by affinity chromatography. As a result, we found that HM-23 inhibited the adhesion of 3LL cells to type IV collagen. The partial amino acid sequences d … More etermined has revealed that HM-23 has homology to fibromodulin, which regulates the formation of collagen fibrils, and that HM-23 is hitherto unknown protein. Cyanogen bromide degradation of HM-23 resulted in generation of two poly-peptides with about 110kDA,suggesting that methionine is present at the center of the molecule. The amino acid sequencing of these polypeptides suggested that this methionine residue is the one contained in one of the three determined sequences. Anti-HM-23 antibodies were used to examine the interaction between HM-23 and extracellular matrix proteins by application of the enzyme-linked immunoadsorbent assay. The results have indicated that HM-23 binds to type I collagen, type IV collagen and gelatin, and to fibronectin weakly, but not to laminin at all. In addition to this mushroom protein exhibiting interaction with animal extracellular matrix proteins, we have also found that rice bran contains fibronectin-binding proteins.These findings on the interaction between non-animal proteins and animal extracellular matrix proteins would open a wide range of biological and cell biological interests which will lead to provide the answers for the problems inculuding cancer metastasis. Less