Calmodulin regulates the post-anaphase reposition of centrioles during cytokinesis

A transient postanaphase repositioning of the centriole is found to control the completion of cytokinesis. Using a green fluorescent protein-calmodulin fusion protein as a living cell probe, we have previously found that calmodulin is associated with the initiation and progression of cytokinesis. In this study, we further studied the effect of calmodulin on the repositioning of the centriole and subsequent cell cycle progression. When activity of calmodulin is inhibited, the regression of the centriole from the intercellular bridge to the cell center is blocked, and thus the completion of cell division is repressed and two daughter cells are linked by longer cell bridge in perturbed cells. W7 treatment during cytokinesis also results in unfinished cytokinesis and stopped G1 phase. These results suggest that calmodulin activity is required for centriole repositioning and can affect the completion of cytokinesis and cell cycle progression.