A centrosome-localized calcium signal is essential for mammalian cell mitosis

Mitosis defects can lead to premature ageing and cancer. Understanding mitosis regulation therefore has important implications for human disease. Early data suggested that calcium (Ca(2+)) signals could influence mitosis, but these have hitherto not been observed in mammalian cells. Here, we reveal a prolonged yet spatially restricted Ca(2+) signal at the centrosomes of actively dividing cells. Local buffering of the centrosomal Ca(2+) signals, by flash photolysis of the caged Ca(2+) chelator diazo-2-acetoxymethyl ester, arrests mitosis. We also provide evidence that this Ca(2+) signal emanates from the endoplasmic reticulum. In summary, we characterize a unique centrosomal Ca(2+) signal as a functionally essential input into mitosis.—Helassa, N., Nugues, C., Rajamanoharan, D., Burgoyne, R. D., Haynes, L. P. A centrosome-localized calcium signal is essential for mammalian cell mitosis.