Mitotic Golgi membranes accumulate at the spindle poles. (A–H) PtK1 cells were stained for the Golgi resident enzyme NAGT I–GFP (A and B) or the Golgi matrix protein GM130 (C–H; green), tubulin (red), and DNA (blue). Upon entry into mitosis, the Golgi ribbon (A) was disassembled into vesicles that clustered around the spindle poles in metaphase (B and C). Mitotic Golgi membranes concentrated at the spindle poles in cells containing monopolar (D), tripolar (E), or tetrapolar (F) spindles as well as in cells with monopolar spindles induced by an Eg5 inhibitor, either monastrol (G) or trityl-cysteine (H). Bar, 4 µm.