News Release

Cellular self-destruction at 30 micrometers per minute

Peer-Reviewed Publication

American Association for the Advancement of Science (AAAS)

Like a wildfire spreading through a dry field, for cells, death comes in an unrelenting wave. A new study finds that death moves throughout the inside of a cell as a trigger wave, spreading the biochemical signal to die over large distances. And this death travels swiftly - at 30 micrometers per minute, according to the findings. Apoptosis is a non-worrisome form of cell death, crucial for the growth of new cells and maintenance of tissues. When a cell decides it's time to die, a self-destruction signal is broadcast, triggering the activation of caspases, which cleave the cell apart from the inside out. However, how this process propagates throughout a cell isn't well understood. This is particularly true for very large cells, like frog eggs, where diffusion is too slow for the larger distances. Previous research has shown the possibility for apoptosis to spread through the cytoplasm as self-regenerating trigger waves, capable of covering large distances without losing speed or strength. Xianrui Chang and James Ferrell propagated apoptosis in extracted cellular material from Xenopus frog eggs in small tubes and used fluorescent probes to visualize the apoptotic signal as it traveled through the cytoplasm. Chang and Ferrell found evidence indicating apoptosis by trigger waves traveling distances greater than 1 millimeter and at a constant speed of nearly 30 micrometers per minute. Similar speeds of cell death were observed in egg cells in vivo, rates too fast to be explained by simple spread via diffusion. The findings establish trigger waves as an important method of biochemical signaling and suggest that similar trigger waves likely occur in many different cell types and in other examples of intra- and intercellular communication.


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