Fig. 7. TGFß increases tTG biosynthesis and its association with ß1 integrins in WI-38 fibroblasts. (A) Effects of TGFß on biosynthesis of Fn, ß1 and ß3 integrins and tTG. ß1, ß3 integrins, tTG, Fn and actin were immunoprecipitated from ³⁵S-labeled lysates (1.8x10⁸ cpm per sample). (B) Effects of TGFß on Fn secretion. Fn was immunoprecipitated from ³⁵S-labeled media (0.2x10⁸ cpm per sample). ³⁵S-labeled cell extracts (A) and secreted proteins in the media (B) of untreated and TGFß-treated cells reflect equal amounts of material taken for immunoprecipitation. (C) Association of tTG with ß1 but not with ß3 integrins is increased in TGFß-treated cells. ß1, ß3 integrins and tTG were immunoprecipitated from untreated or TGFß-stimulated cells and the immune complexes were blotted for tTG (lower panels) or ß1 and ß3 integrins (upper panels).