Fig. 7. The PDI–hEROs pathway is involved in the oxidative folding of Ig-κ chain, a non-glycosylated, secreted cargo protein. (A) HeLa cells were co-transfected with pcDNA.3-κ-myc and pcDNA3.1-ERO1-Lα or pcDNA3.1ERO1-LαC394Α. Cells were pulse-labelled for 5 min in the presence of DTT and chased without the reducing agent for the indicated times before lysis and immunoprecipitation with anti-myc. (B) Lysates from HeLa transfectants labelled as described in (A) were immunoprecipitated with anti-myc or with an antibody raised against native κ chains (goat anti-mouse κ) and resolved under non-reducing conditions. Note that anti-κ does not precipitate completely reduced κ chains.