Marked mitochondrial alterations upon starvation without cell death, caspases or Bcl-2 family members.

Dictyostelium HMX44A cells can withstand starvation under monolayer conditions for a few days without dying. They die only when the differentiation factor DIF-1 is exogenously added. Still, when HMX44A were subjected to starvation without addition of DIF-1 they showed, by electron microscopy and electron tomography, gross mitochondrial lesions including marked cristae alterations with frequent "holes" probably originating from dilated cristae. Since these cells did not die as shown for instance by FACS analysis, these results showed unexpected resilience of cells bearing markedly altered mitochondria, and thus showed that apparently destructive mitochondrial alterations may not lead to cell death. Also, these marked mitochondrial lesions could not be caused by caspases or bcl-2 family members, which these cells do not encode.