Figure 3

HB-EGF-induced HER1 phosphorylation. (A) HER1 autophosphorylation pattern derived from mass spectrometry analysis of trypsin-digested peptides from HeLa cells stimulated with 25 ng/mL HB-EGF for 20 minutes. Seven phosphorylation sites are represented as phosphorylation ratio (phosphorylation after stimulus/basal phosphorylation). (B) HeLa and DLD-1 cells were stimulated with 25 ng/mL HB-EGF for 20 minutes. Phosphorylation of HER1 and ERK1/2 was measured by ELISA and is expressed as phosphorylated molecules/total molecules and represented as per cent ratio. The means ± SD of 10 experiments are depicted.