Fig. 1. Epilysin induces EMT in A549 cells. (A) Cell pools stably expressing epilysin were prepared by puromycin selection of A549 cells transfected with expression constructs for either wild-type (Epi) or a catalytically inactive mutant (Epi-E/A) of epilysin. Ctrl denotes empty vector-transfected controls that have undergone the same selection procedure. Conditioned serum-free media from the cell pools were harvested and polypeptides were detected with epilysin specific antibodies (active epilysin: 48 kDa). (B) Immunofluorescence studies were performed with antibodies specific for the extracellular part of E-cadherin. To avoid internalization of the antibodies during the procedure, living cells were incubated on ice with primary antibodies, fixed with PFA and incubated with secondary Alexa-conjugated antibodies. Coverslips were mounted using a mounting medium containing DAPI. E-cadherin: red; DAPI: blue. (C) Immunoblotting of E-cadherin was performed with antibodies recognizing its ectodomain (shed degradation product 80 kDa).