Figure 1. Expression of CCN1 and CCN1 mutants in MCF-7 breast cancer cells. Top: Schematic diagram showing the modular domain structure of wild-type CCN1 with the localization of several identified integrin-binding sites, and mutants either bearing the D125A mutation in vWC (D125A-CCN1) or combined mutations in T1, H1, and H2 in TSP1 and TC domains (TM-CCN1). IGFBP, insulin-like growth factor binding protein; vWC, von Willebrand factor type C repeats; TSP-1, thrombospondin type 1; CT, C-terminus. Bottom: Immunoblotting assessment of endogenous CCN1 protein in CCN1-overexpressing MDA-MB-231 cells and in MCF-7 cells retrovirally transduced with an empty vector (pBABE) or a vector containing either wild-type CCN1 or D125A-CCN1 and TM-CCN1 mutants. Microphotographs show representative in situ immunofluorescence staining of CCN1 in MCF-7/pBABE, MCF-7/CCN1, MCF-7/D125A-CCN1, and MCF-7/TM-CCN1 cells. Scale bar is 10 μm. Results are representative of three independent experiments.