Localized Ca²⁺ signal has been suspected to play an important role in regulating cytokinesis, but so far the evidence has been indirect and controversial. In this study, we combined the usage of a sensitive fluorescence Ca²⁺ indicator and laser scanning confocal microscope, and were able to demonstrate the existence of a spatially and temporally localized elevation in intracellular free calcium concentration ([Ca²⁺]i) in the cleavage furrow region in zebrafish embryo. Results of this study also showed that this transient elevation in [Ca²⁺]_i is necessary for the onset of cytokinesis. The source of Ca²⁺ contributing to this localized elevation of [Ca²⁺] _i is mainly from intracellular Ca²⁺ stores released through InsP₃ receptors. Results of this study strongly support the hypothesis that...[ Read more ]

Localized Ca²⁺ signal has been suspected to play an important role in regulating cytokinesis, but so far the evidence has been indirect and controversial. In this study, we combined the usage of a sensitive fluorescence Ca²⁺ indicator and laser scanning confocal microscope, and were able to demonstrate the existence of a spatially and temporally localized elevation in intracellular free calcium concentration ([Ca²⁺]i) in the cleavage furrow region in zebrafish embryo. Results of this study also showed that this transient elevation in [Ca²⁺]_i is necessary for the onset of cytokinesis. The source of Ca²⁺ contributing to this localized elevation of [Ca²⁺] _i is mainly from intracellular Ca²⁺ stores released through InsP₃ receptors. Results of this study strongly support the hypothesis that a localized Ca²⁺ signal plays an important role in regulating cytokinesis.