Endogenous MyoGEF localizes to the spindle pole, central spindle, and cleavage furrow. (A) Characterization of a polyclonal antibody specific for MyoGEF. An immunoblot analysis shows that a polyclonal antibody against MyoGEF recognizes the endogenous, GFP-tagged, and His-tagged MyoGEF in HeLa cells (upper panel, lanes 1, 2, and 3) as well as endogenous MyoGEF in U2OS cells (upper panel, lane 4). (B) Localization of endogenous MyoGEF during cytokinesis. U2OS cells growing on coverslips were fixed in 10% trichloroacetic acid and stained with antibodies specific for MyoGEF (green) and beta-tubulin (red). Note that MyoGEF localizes to the spindle pole in metaphase (a–c), to the spindle pole and central spindle in anaphase (d–f), and to the spindle pole and cleavage furrow in telophase (g–i). Arrowheads in a–i indicate the localization of MyoGEF to the spindle pole. Arrows in d–f indicate the localization of MyoGEF to the central spindle. Arrows in g–i indicate the localization of MyoGEF to the cleavage furrow. Bar, 10 μm.