Dictyostelium Cell Death by Sparagmosis

Example 4

The expression of RasC^Q62L in pten− cells maintained for an additional 16-28 hours resulted in cells that underwent a catastrophic fragmentation and death (FIG. 6). It was verified that 98% of the induced cells were dead by Trypan Blue staining and their failure to form foci on re-plating. The surviving 2% of cells were not flattened, indicating that they lost expression of RasC^Q62L. This observed mode of cell death has not been elucidated before in either Dictyostelium or in mammalian cells. This mechanism was named “sparagmosis” from the Greek sparasso, meaning “tear, rend, or pull to pieces.” Other pairwise combinations of perturbations that generated flattened cells such as expression of RasC^Q62L in RAM mutants or expression of Rap1A^G12V in pten− also led to similar cell death by fragmentation.