ERBB2 Transactivation: Serum starved A431 cells were treated for 15 min as indicated. Whole cell lysates were separated by SDS-PAGE (ca 20.000 cells/lane). The immunoblot was probed with mab erbB2-7F8 (0.5 ug/ ml) for 1h at RT and developed by ECL (exp. time: 30 sec). Lane 1: Control Lane 2: PMA Lane 3: LPA Lane 4: Ceramide Lane 5: Bradykinin Lane 6: Bombesin