Coexpression of EFsec and SBP2 minimal functional domain results in partial nuclear localization of EFsec in HEK-293 cells. Localization was performed following cotransfection of EFsec and SBP2 (A to D) or EFsec and SBP2 399-777 (E and F). Panel A indicates EFsec (FLAG antibody, red). Panel B indicates SBP2 (V5 antibody, green) plus EFsec (FLAG antibody, red). (C and D) Antibody plus DAPI staining (blue) as for panels A and B, respectively. Panel E indicates EFsec (FLAG antibody). Panel F indicates SBP2 399-777 (V5 antibody, green) plus EFsec (FLAG antibody, red). Immunostaining conditions used were as described in the legend for Fig. 2; arrows indicate increased nuclear localization of EFsec in cells coexpressing SBP2 399-777.