Epidermal growth factor (EGF) stimulates increased nuclear localization of Jab1 in MDA-MB-231 and MDA-MB-468 breast cancer cell lines. (a, b) Immunofluorescence assays. (c) Quantitative image analysis of nuclear Jab1 (bars represent mean ± standard deviation). Statistical analysis was by t test (*P < 0.01). (d) Increased expression of Jab1 in the nucleus relative to cytoplasm, detected by Western blot in MDA-MB-231 nuclear extracts. Lamin A/C was included as a positive control for the nuclear extract, and GAPDH was included as a loading control. (e) Increased Jab1 nuclear expression positively correlated to EGF dose. DAPI, 4'-6-diamidino-2-phenylindole; GAPDH, glyceraldehyde 3-phosphate dehydrogenase; Jab1, c-Jun activation domain-binding protein-1.