Fig. 5. TGF-β rapidly induces the degradation of endogenous HEF1 in the T-lymphoblastoid H9 cell line in a time-dependent fashion. (A) Endogenous p115HEF1 and p105HEF1 are reduced upon TGF-β stimulation in H9 cells. At various time points after exposure to 400 pM TGF-β, lysates were prepared from H9 cells and immunoprecipitated with α-HEF1 antibody. Precipitated HEF1 was revealed subsequently by western blotting with the same antibody. (B) Quantification of the endogenous p115HEF1 and p105HEF1 protein levels in (A). The levels of both p115HEF1 and p105HEF1 in (A) were quantified using Imagemaster 1D (Pharmacia) and plotted as integrated optical density (IOD) using Microsoft Excel.