There are four biding cell sites in the Fn molecular, three of them is in the FnCTD_64, the function of the sites is to promote cells attaching and migrating.

• 重组纤维连接蛋白羧基端细胞结合域(FnCTD_(64))由607个氨基酸构成,是Fn分子中靠近羧基端的细胞结合位点,Fn有四个细胞结合位点,FnCTD_(64)中就含有三个,与Fn相比,它具有来源充足、无传染性、不引起免疫反应等特点。