Fig. 4.

EGFR signaling is enhanced in EGFR +/Dsk5 livers. A: changes in the phosphorylation (top) and total expression (bottom) of EGFR (left) and ERBB3 (right) in livers of 6-wk-old male mice. Note that there is decreased expression of EGFR but increased phosphorylation of this protein in the +/Dsk5 mice compared with +/+ littermates. In contrast, ERBB3 levels are similar if not increased in the +/Dsk5 mice but also show increased phosphorylation. Bottom: phosphorylation and total expression of 2 proteins involved in EGFR signaling, namely Erk 1–2 and Akt. Note the enhanced phosphorylation of Erk 1–2 and Akt in the +/Dsk5 mice. B: representative immunohistochemical sections from the livers of +/Dsk5 and +/+ mice that have been stained with antibodies against pY-1068 EGFR or EGFR.