The various EGF-like ligands induce differential
tyrosine phosphorylation and MAPK activation in the 32D.E4 and
32D.E2/D4 transfectants. (A) Detection of EGF-like
ligand-induced tyrosine phosphorylation of cellular proteins in 32D.E4
and 32D.E2/E4 cells. Lysates from untreated cells (Control) or cells
treated with EGF, NRG1-β, BTC, TGF-α, HB-EGF, or AR were
immunoprecipitated (IP) and subsequently immunoblotted (Blot) with
anti-pTyr as designated. Molecular mass markers are given in kDa.
(B) The effects of EGF-like ligand treatment on the potency
and duration of MAPK activation in 32D.E4 and 32D.E2/E4 cells.
Lysates from untreated cells (O) or cells treated with the various
EGF-like ligands for 5, 10, 30, or 60 min were subjected to immunoblot
analysis with an antibody that specifically recognizes the activated
forms of Erk1 and Erk2 marked by arrows.