Recombinant human FN peptides.

(A) A schematic representation of FN peptides. FN is made up of series of type I, II, and III repeats. Regions of FN with cell-binding activity are shown as the RGD-containing cell-binding domain (CELL), which is recognized by integrin α₅β₁, the nonintegrin-dependent high-affinity heparin-binding site (HEP), and the alternatively spliced non–type III connecting segment (III CS) that is recognized by integrin α₄β₁ (CS-1). The recognition sites for integrin α₄β₁, α₅β₁, as well as the heparin-binding site on FN are indicated by an arrow. (B) Expression of integrins and c-Kit on G1E-ER2 cells. G1E-ER2 cells were stained with anti–c-Kit-PE and analyzed by flow cytometry. The thin line indicates the level of background staining observed with appropriate isotype control antibody. The thick line indicates the level of c-Kit expression. (C) G1E-ER2 cells were stained with anti–α₄β₁-FITC and analyzed by flow cytometry. The thick line indicates the level of α₄β₁ expression. (D) G1E-ER2 cells were stained with anti–α₅β₁-PE and analyzed by flow cytometry. The thick line indicates the level of α₅β₁ expression.