Orchestration of Force Generation and Nuclear Collapse in Apoptotic Cells

Apoptosis, or programmed cell death, is a form of cell suicide that is extremely important for ridding the body of cells that are no longer required, to protect the body against hazardous cells, such as cancerous ones, and to promote tissue morphogenesis during animal development. Upon reception of a death stimulus, the doomed cell activates biochemical pathways that eventually converge on the activation of dedicated enzymes, caspases. Numerous pieces of information on the biochemical control of the process have been gathered, from the successive events of caspase activation to the identification of their targets, such as lamins, which constitute the nuclear skeleton. Yet, evidence from multiple systems now shows that apoptosis is also a mechanical process, which may even ultimately impinge on the morphogenesis of the surrounding tissues. This mechanical role relies on dramatic actomyosin cytoskeleton remodelling, and on its coupling with the nucleus before nucleus fragmentation. Here, we provide an overview of apoptosis before describing how apoptotic forces could combine with selective caspase-dependent proteolysis to orchestrate nucleus destruction.