Fig. 4.

E-cadherin and integrins cooperate to activate EGFR and downstream Erk1/2 in mechanically perturbed epithelia. In panels A–D, cells were subjected to four conditions: ±10% cyclic stretch and ±3 nM EGF for 30 min followed by Western blot analysis of pY845, pY1173, total EGFR, pErk1/2, and total Erk1/2. Cells were serum starved overnight, and EGF-neutralizing antibody was applied to all non–EGF-treated samples. (A) A-431D^E-cad cells were plated at monolayer density on E-cad-Fc–coated PDMS membranes and allowed to attach for 5 h in the presence of 16G3 antibody. (B) A-431D^E-cad cells seeded on fibronectin-coated PDMS membranes at confluent density. (C) A-431D^E-cad cells were plated on fibronectin-coated PDMS membranes for 5 h at subconfluent cell density to prevent cell–cell contacts. (D) Confluent A-431D^E-cad monolayers on fibronectin-coated PDMS membranes at monolayer density were serum starved overnight. Cells were treated with DECMA-1 for 30 min to disrupt cell–cell junctions.