Smurf2 is a cell cycle–regulated protein localizing specifically in the centrosome, mitotic midzone, and midbody. (a) HeLa cells were synchronized by a double-thymidine protocol. At the indicated hours after release from the block, cells were analyzed by immunoblotting for the proteins shown. (b) Immunofluorescence microscopy for γ-tubulin (green) and Smurf2 (red) in HeLa cells at interphase and metaphase. Polyclonal anti-Smurf2 antibody was used for Smurf2 staining. DAPI was used to stain chromosomal DNA (blue). The close-up images are shown with threefold higher magnification. (c) Immunofluorescent staining for α-tubulin (green) and Smurf2 (red) in human mammary epithelial MCF-10A cells during mitosis. Bars, 10 μm.