Messages from Beyond the Grave: How Can Drosophila Help Us Understand the Consequences of Apoptosis?

Cell death is an integral part of life. Cells strategically die during the embryonic development of an organism to help sculpt developing tissues into their final form, and cells are constantly lost and replaced during homeostasis as well as through injury. In each of these scenarios, the resulting corpses must be efficiently cleared, and surviving cells must react to the loss of their dying neighbour appropriately such that the health and function of the tissue is maintained. For this to happen effectively, healthy cells need to be alerted to a death in their community rapidly and efficiently. Fortunately, cell death is not a silent process, there is no quiet drifting off into the afterlife for the departing cell but instead it announces its demise through the creation of a plethora of signals both secreted and membrane bound designed to make its neighbours aware of its imminent departure. The fruit fly Drosophila melanogaster through its powerful genetics and live imaging has proved an invaluable model in helping researchers understand not only the signalling that drives the process of programmed cell death but also the complex multicellular communications within a tissue that influence a cell's decision to die as well as the downstream consequences of that death. Here, we highlight how research using the humble fly can help to understand the complex multicellular coordination required to successfully deal with the loss of a cell within the complex setting of a three-dimensional living organism.