Wu L N, Genge B R, Lloyd G C, Wuthier R E
Department of Chemistry, University of South Carolina, Columbia 29208.
J Biol Chem. 1991 Jan 15;266(2):1195-203.
Recent evidence indicates that matrix vesicles (MV) interact with cartilage-specific collagens and other matrix proteins. Both type II and X collagens bind to and cosediment with MV. Our companion study shows that MV also are tightly coupled to proteoglycan link proteins (LP) and hyaluronic acid-binding region (HABR) in cartilage matrix. Here we sought to identify proteins responsible for the nexus between MV and matrix collagens using affinity chromatography with types I, II, and X collagen-Sepharose columns. Elution with NaCl step-gradients in the presence of nonionic detergent was used to assess the affinity between the MV proteins and the covalently attached collagens. Several MV proteins were found to bind to native type I, II, and X collagens but none bound to denatured type I collagen. Alkaline phosphatase, proteoglycan LP and HABR, and the 33- and 67-kDa annexins, bound with varying affinities to the native type I, II and X columns. In particular, LP and HABR, the 67-kDa annexin, and alkaline phosphatase bound with high affinity to the cartilage-specific collagens, although LP, HABR, and a 37-kDa protein also bound less tightly to native type I collagen. Thus, several MV proteins bind specifically to native type II and X collagens and should promote interaction between MV and the extracellular matrix. Such interactions may be important in MV formation, or in MV-mediated mineralization.
最近的证据表明，基质小泡（MV）与软骨特异性胶原蛋白及其他基质蛋白相互作用。II型和X型胶原蛋白均与MV结合并与之共同沉降。我们的相关研究表明，MV还与软骨基质中的蛋白聚糖连接蛋白（LP）和透明质酸结合区域（HABR）紧密相连。在此，我们试图通过使用I型、II型和X型胶原-琼脂糖柱进行亲和层析，来鉴定负责MV与基质胶原蛋白之间联系的蛋白质。在非离子去污剂存在的情况下，用NaCl梯度洗脱来评估MV蛋白与共价连接的胶原蛋白之间的亲和力。发现几种MV蛋白可与天然I型、II型和X型胶原蛋白结合，但无一与变性I型胶原蛋白结合。碱性磷酸酶、蛋白聚糖LP和HABR以及33 kDa和67 kDa的膜联蛋白，以不同的亲和力与天然I型、II型和X型柱结合。特别是，LP和HABR、67 kDa的膜联蛋白以及碱性磷酸酶与软骨特异性胶原蛋白具有高亲和力结合，尽管LP、HABR和一种37 kDa的蛋白也与天然I型胶原蛋白结合得较松散。因此，几种MV蛋白特异性地与天然II型和X型胶原蛋白结合，应该会促进MV与细胞外基质之间的相互作用。这种相互作用在MV形成或MV介导的矿化过程中可能很重要。
