CHICK MYOTENDINOUS ANTIGEN .2. A NOVEL EXTRACELLULAR GLYCOPROTEIN COMPLEX CONSISTING OF LARGE DISULFIDE-LINKED SUBUNITS
CHICK MYOTENDINOUS ANTIGEN .2. A NOVEL EXTRACELLULAR GLYCOPROTEIN COMPLEX CONSISTING OF LARGE DISULFIDE-LINKED SUBUNITS
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DOI：
10.1083/jcb.98.6.1937
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发表时间：
1984-01-01
影响因子：
7.8
通讯作者：
FAMBROUGH, DM
中科院分区：
文献类型：
--
作者：
CHIQUET, M;FAMBROUGH, DM
本报告描述了一种新型细胞外基质成分——肌腱抗原的生化特性。它在鸡胚肢体形态发生早期出现在连接发育中的肌纤维、肌腱和骨骼的部位。这种细胞外基质抗原是成纤维细胞和肌肉培养物释放到培养基中的分泌蛋白的主要成分；这里对其可溶性形式进行了表征。这种形式的肌腱抗原是一种大型糖蛋白复合物，由几个通过二硫键连接的亚单位组成（分子量约为150,000 - 240,000）。不同大小的抗原亚单位是相关的，因为它们产生非常相似的蛋白水解裂解模式。M1抗体能够与变性的亚单位结合。抗原亚单位以及从它们衍生出的分子量约为80,000的抗胃蛋白酶抗原结构域对细菌胶原酶具有抗性。尽管肌腱抗原拥有与纤连蛋白大小相似的亚单位，但它在结构和抗原性上似乎与纤连蛋白或其他已知的细胞外基质成分均无关。与肌肉培养物相比，成纤维细胞中每个细胞核释放到培养基中的M1抗原大约多7倍。在肌肉条件培养基中，肌腱抗原与分子量非常高的物质非共价结合，这种物质可以被[³H]葡萄糖胺和[³⁵S]硫酸盐大量标记。这种物质对软骨素酶ABC敏感，因此似乎含有硫酸化的糖胺聚糖。肌腱抗原可能与肌纤维表面的蛋白聚糖相互作用，从而起到连接肌腱的作用。
This report describes the biochemical characterization of a novel extracellular matrix component, myotendinous antigen, which appears early in chick limb morphogenesis at sites connecting developing muscle fibers, tendons and bone. This extracellular matrix antigen is a major component of the secretory proteins released into the medium by fibroblast and muscle cultures; the soluble form is characterized here. This form of myotendinous antigen is a large glycoprotein complex consisting of several disulfide linked subunits (MW .apprx. 150,000-240,000). The differently sized antigen subunits are related, since they yielded very similar proteolytic cleavage patterns. M1 antibody can bind to the denatured subunits. The antigen subunits, as well as a MW .apprx. 80,000 pepsin-resistant antigenic domain derived from them, are resistant to bacterial collagenase. Despite possessing subunits similar in size to fibronectin, myotendinous antigen appears to be both structurally and antigenically unrelated to fibronectin or to other known extracelluar matrix components. About 7 times more M1 antigen per cell nucleus was released into the medium in fibroblast as compare to muscle cultures. In muscle conditioned medium, myotendinous antigen is noncovalently complexed to very high MW material that could be heavily labeled by[3H]glucosamine and [35S]sulfate. This material is sensitive to chondroitinase ABC and hence appears to contain sulfated glycosaminoglycans. Myotendinous antigen might interact with proteoglycans on the surface of muscle fibers, thereby acting as a link to tendons.