Figure 3.

Western blot analysis of IGF-1R processing in WT and transgenic primary keratinocyte cultures (A). The cells were challenged in vitro with different doses of the PC inhibitor CMK to investigate the sensitivity of primary keratinocytes to IGF-1R cleavage inhibition by CMK; 3 µM CMK, and more clearly after 12.5 µM CMK, was able to inhibit PC-mediated IGF-1R processing in WT keratinocytes. The effect was noted by the presence of IGF-1R precursor or proform with increasing concentrations of CMK. Conversely, the CMK treatment failed to increase significantly the levels of the IGF-1R precursor in SF47- and SF49-derived cells. Panel B shows these changes as depicted by plotting the ratios of densitometric evaluations of IGF-1R precursor to processed bands.