“A little bit about caspase-dependent pro-survival functions in stem cells”

The unidimensional and dominating view of caspases as purely apoptotic proteins has rapidly changed in recent years. Indeed, it is becoming clear that the enzymatic activity of this protein family is essential for the proper regulation of other cellular processes, beyond cell death. These novel non-apoptotic roles appear to be highly diverse and can modulate a large array of basic cellular properties in many cell types, including stem cells. Throughout the talk, I will describe our recent findings which illustrate the pleiotropic, non-apoptotic and tissue-specific function of caspases in progenitor cells. I will also discuss the potential molecular mechanisms underlying these functions. According to our findings, the non-apoptotic activation of caspases may be a common feature of stem cells which ensures the fine-tuning of specific signalling cascades, and consequently cellular processes such as cell differentiation and cell proliferation. In light of these results, we suggest that the primary role attributed to these enzymes should be reconsidered. The induction of apoptosis may be their more phenotypically apparent function, but not necessarily the more ancient and/or relevant.