Woods A, Johansson S, Höök M
Department of Cell Biology, Buris R. Boshell Diabetes Research and Training Center, University of Alabama at Birmingham 35294.
Exp Cell Res. 1988 Aug;177(2):272-83. doi: 10.1016/0014-4827(88)90461-2.
Fibronectin fragments and domain-specific antibodies have been used to study the mechanism by which cells reorganize exogenous fibronectin substrata into fibrils. Fibroblasts prevented from protein synthesis, and hence not secreting endogenous fibronectin or other matrix components, reorganized exogenous fibronectin substrata into arrays resembling the matrix of normally cultured cells. Cells also formed fibrils from substrata containing mixtures of cell- and either of two different heparin-binding fibronectin fragments but not from either fragment alone. The gelatin-binding fragment alone or in conjunction with the cell-binding fragment did not promote fibril formation. Antibodies recognizing cell- and either heparin- or the gelatin-binding domains labeled fibrils formed by cells under normal culture conditions or when a substratum of intact fibronectin was used as the sole exogenous source. However, only antibodies recognizing the cell- or either heparin-binding fragment reduced fibrillogenesis from intact fibronectin substrates when added during cell spreading. These data suggest that formation of fibronectin fibrils can occur at the cell surface and that membrane components recognizing the cell- and the heparin-binding domains in fibronectin may cooperate in the assembly process.
纤连蛋白片段和结构域特异性抗体已被用于研究细胞将外源性纤连蛋白基质重组成纤维的机制。阻止蛋白质合成从而不分泌内源性纤连蛋白或其他基质成分的成纤维细胞，将外源性纤连蛋白基质重组成类似于正常培养细胞基质的阵列。细胞还能从含有细胞与两种不同肝素结合纤连蛋白片段之一的混合物的基质中形成纤维，但不能从单独的任何一种片段中形成纤维。单独的明胶结合片段或与细胞结合片段一起都不能促进纤维形成。识别细胞以及肝素或明胶结合结构域的抗体标记了在正常培养条件下细胞形成的纤维，或者当完整纤连蛋白基质用作唯一外源性来源时细胞形成的纤维。然而，当在细胞铺展过程中添加时，只有识别细胞或肝素结合片段之一的抗体减少了从完整纤连蛋白底物形成的纤维形成。这些数据表明纤连蛋白纤维的形成可以在细胞表面发生，并且识别纤连蛋白中细胞和肝素结合结构域的膜成分可能在组装过程中协同作用。
