Increases in EGFR protein expression and phosphorylation of EGFR at Tyr1173 in MKN45/PAR1 stimulated with α-thrombin. MKN45/PAR1 were stimulated with 15 nM α-thrombin for 1, 3, 6, and 12 hr and harvested for preparing whole cell lysates. The clear extracts containing 100 μg protein was developed on SDS-PAGE. We detected by western blotting experiment using an antibody raised against total EGFR (dilution of 1: 500) was increased 3 hr after addition of 15 nM α-thrombin to MKN45/PAR1. But we detected using an antibody raised against phosphotyrosine (Tyr1173) that tyrosine phosphorylation of EGFR (dilution of 1:500) was slightly increased 1 hr after addition of 15 nM α-thrombin, and following 3 hr, phospho-EGFR was dramatically increased.