This HeLa cell, which is expressing both a kinetochore marker (EGFP-CENP-B) and a centrosome marker (Venus-centrin), has been depleted of the spindle assembly checkpoint protein Mad2. In the absence of Mad2, the cell rapidly progresses from early prometaphase through anaphase and cytokinesis. The spindle assembly checkpoint functions to generate a WAIT signal until all sister kinetochore pairs become properly attached to the mitotic spindle. Loss of checkpoint function leads to anaphase initiation before kinetochores are completely aligned at the spindle equator. Despite the rapid nature of these divisions, the majority of the kinetochores appear to separate properly in Mad2-depleted cells. However, at least a few lagging chromosomes are frequently observed in these cells, demonstrating the importance of checkpoint function. Note that the frame width is approximately 30 microns. This movie is part of a group that captured first place at the 2007 ASCB Celldance contest.