*Center for Biochemistry, Medical Faculty, University of Cologne, 50931 Cologne, Germany.
‡Center for Molecular Medicine, Department of Vascular Biology, Excellence Cluster Cardio-Pulmunary System, Frankfurt University Hospital, 60590 Frankfurt am Main, Germany.
Biochem J. 2014 Apr 1;459(1):217-27. doi: 10.1042/BJ20130642.
Collagen XXII, a FACIT (fibril-associated collagen with interrupted triple helices), is expressed at the myotendinous junction and the articular surface of joint cartilage. Cellular receptors like collagen-binding integrins are known to bind collagens with distinct binding motifs following the sequence GXOGER. In the present study, we demonstrate the sequences GLQGER and GFKGER as novel binding motifs between collagen XXII and collagen-binding integrins, especially α2β1 integrin. Solid-phase assays and surface plasmon resonance spectroscopy revealed a direct interaction between α2β1 integrin and the motif GFKGER. In addition, immunohistochemical analysis demonstrated partial co-localization of collagen XXII, α2β1 integrin and α11β1 integrin at the myotendinous junction. Furthermore, computational modelling of the motifs GLQGER and GFKGER showed perfect fitting of the sequences into the binding pocket of collagen-binding integrins. Taken together, we demonstrated that collagen XXII interacts with collagen-binding integrins via the new motifs GLQGER and GFKGER.
胶原 XXII 是 FACIT（纤维相关胶原中断三螺旋）家族的一员，在肌腱-肌肉连接点和关节软骨的关节表面表达。已知细胞受体如胶原结合整联蛋白，能通过特定的结合基序与具有不同序列的胶原结合。在本研究中，我们证明了 GLQGER 和 GFKGER 序列是胶原 XXII 与胶原结合整联蛋白，特别是α2β1 整联蛋白之间的新结合基序。固相分析和表面等离子体共振光谱显示，α2β1 整联蛋白与 GFKGER 基序之间存在直接相互作用。此外，免疫组织化学分析显示，胶原 XXII、α2β1 整联蛋白和α11β1 整联蛋白在肌腱-肌肉连接点部分共定位。此外，GLQGER 和 GFKGER 基序的计算建模显示，这些序列与胶原结合整联蛋白的结合口袋完全吻合。综上所述，我们证明了胶原 XXII 通过新的 GLQGER 和 GFKGER 基序与胶原结合整联蛋白相互作用。
