Fig. 1. A detergent-resistant fraction of importin ß in HeLa cells. (A) IF analysis of importin ß in interphase (a,c) or mitotic (b,d) cells after PFA fixation (a,b) or TritonX-100 pre-extraction (c,d); in each series, importin ß is depicted on the left and DAPI staining on the right. Scale bars, 10 µm. (B) Confocal co-localization of importin ß (FITC, green) and -tubulin (rhodamine, red) at spindle poles of a metaphase HeLa cell. (C) Merged signals colocalize to poles throughout all sections of the metaphase; representative focal planes (0.37 µm sections) are shown.