Fig. 7: Gab1 and Grb2 are involved in pY772-EphA2-activating Shp2/Erk-1/2 signaling pathway in the NPC cells.

a Western blotting showing the levels of p-Shp2 (Y542/Y580) and p-Erk-1/2 in the EphA2-WT-expressed NPC cells infected with the lentiviral vector expressing Gab1 shRNA, and their control cells. b Co-IP showing the levels of p-Shp2(Y542/580) and Shp2 bound to EphA2 in the EphA2-WT-expressed NPC cellsinfected with the lentiviral vector expressing Gab1 shRNA, and their control cells. Total cell proteins from the infected cells were prepared and subjected to immunoprecipitation immunoprecipitation (IP) with anti-EphA2 antibody followed by immunoblotting with antibodies against p-Shp2 (Y542/Y580), Shp2, or EphA2. c Co-IP analysis showing the levels of Grb2 bound to Shp2 in the EphA2-WT-expressed NPC cells infected with the lentiviral vector expressing Gab1 shRNA, and their control cells. Total cell proteins from the infected cells were prepared and subjected to immunoprecipitation (IP) with anti-Shp2 antibody followed by immunoblotting with antibodies against Grb2 or Shp2. d Co-IP showing the levels of p-Gab1, Gab1, and Grb2 bound to Shp2 in the NPC cells expressing EphA2-WT or EphA2-YA and their control cells. Total cell proteins from the indicated cells were prepared and subjected to immunoprecipitation with anti-Shp2 antibody followed by immunoblotting with antibodies against p-Gab1, Gab1, Grb2, or Shp2. e A model for pY772-EphA2-dependent NPC cell growth. EphA2 is phosphorylated at Y772 by growth factors in a ligand-independent manner and phosphorylation of EphA2 at Y772 (pY772-EphA2) activates Shp2/Erk-1/2 signaling, and both Gab1 and Grb2 are involved in pY772-EphA2-activating Shp2/Erk-1/2 activation, which promotes NPC cell growth. EphA2 tyrosine kinase inhibitor ALW-II-41-27 inhibits pY772-EphA2, which blocks NPC cell growth.