Nucleoplasmic calcium is required for cell proliferation

Ca2+ signals regulate cell proliferation, but the spatial and temporal specificity of these signals is unknown. Here we use selective buffers of nucleoplasmic or cytoplasmic Ca2+ to determine that cell proliferation depends upon Ca2+ signals within the nucleus rather than in the cytoplasm. Nuclear Ca2+ signals stimulate cell growth rather than inhibit apoptosis and specifically permit cells to advance through early prophase. Selective buffering of nuclear but not cytoplasmic Ca2+ signals also impairs growth of tumors in vivo. These findings reveal a major physiological and potential pathophysiological role for nucleoplasmic Ca2+ signals and suggest that this information can be used to design novel therapeutic strategies to regulate conditions of abnormal cell growth.