Shi Shuiliang, Grothe Suzanne, Zhang Yiping, O'Connor-McCourt Maureen D, Poole A Robin, Roughley Peter J, Mort John S
Joint Diseases Laboratory, Shriners Hospitals for Children, 1529 Cedar Avenue, Montreal, Quebec, Canada H3G 1A6.
J Biol Chem. 2004 Mar 26;279(13):12060-6. doi: 10.1074/jbc.M310091200. Epub 2004 Jan 14.
The function of link protein in stabilizing the interaction between aggrecan and hyaluronan to form aggrecan aggregates, via the binding of link protein to the aggrecan G1 domain and hyaluronan, is well established. However, it is not known whether link protein can function with similar avidity with versican, another member of the large hyaluronan-binding proteoglycan family that also binds to hyaluronan via its G1 domain. To address this issue, we have compared the interaction of the versican and aggrecan G1 domains with link protein and hyaluronan using recombinant proteins expressed in insect cells and BIAcore analysis. The results showed that link protein could significantly improve the binding of both G1 domains to hyaluronan and that its interaction with VG1 is of a higher affinity than that with AG1. These observations suggest that link protein may function as a stabilizer of the interaction, not only between aggrecan and hyaluronan in cartilage, but also between versican and hyaluronan in many tissues.
连接蛋白通过与聚集蛋白聚糖G1结构域和透明质酸结合，在稳定聚集蛋白聚糖与透明质酸之间的相互作用以形成聚集蛋白聚糖聚集体方面的功能已得到充分证实。然而，尚不清楚连接蛋白是否能与多功能蛋白聚糖（versican）以类似的亲和力发挥作用，多功能蛋白聚糖是大型透明质酸结合蛋白聚糖家族的另一个成员，它也通过其G1结构域与透明质酸结合。为了解决这个问题，我们使用在昆虫细胞中表达的重组蛋白和BIAcore分析，比较了多功能蛋白聚糖和聚集蛋白聚糖G1结构域与连接蛋白和透明质酸的相互作用。结果表明，连接蛋白可以显著提高两个G1结构域与透明质酸的结合，并且其与VG1的相互作用亲和力高于与AG1的相互作用。这些观察结果表明，连接蛋白可能不仅作为软骨中聚集蛋白聚糖与透明质酸之间相互作用的稳定剂，而且在许多组织中作为多功能蛋白聚糖与透明质酸之间相互作用的稳定剂发挥作用。
