Fig. 1. ERK5 is localized in the nucleus in Rat-1 cells. (A) Rat-1 cells were grown on coverslips, fixed with PFA, permeabilized with 0.2% Triton X-100 and stained with rabbit anti-ERK5 antibody directed to the C terminus of ERK5 in the presence or absence of blocking peptide (50 µg/ml). (B) Rat-1 cells were treated as described above and stained with antibodies to different epitopes of ERK5 (N-19, C-20, H-300).