Fig. 3. UV-irradiation did not induce dimerisation of the EGFR. Cells were left untreated, or exposed to 50 J/m² UV (lanes 1,2), 200 J/m² UV (lanes 3,4), or EGF (10 nM on ice for 15 minutes). The UV-exposed cells were either irradiated at 37°C and incubated for 2 minutes at the same temperature (lanes 1,3), or irradiated on ice and further incubated on ice for 15 minutes (lanes 2,4). All samples were incubated with the crosslinker BS³ on ice for 20 minutes. Cell lysates were subject to SDS-PAGE and western immunoblotting with anti-EGFR. The band with molecular mass around 340 kDa representing dimeric EGFR is indicated (arrow). C and E denote control and EGF-stimulated cells, respectively. The molecular weight marker presented at the left indicates 220 kDa.