Can a tiny winged insect's salivary glands really tell us about processes relevant to human disease? Yes, according to a new study by researchers at the University of Massachusetts Medical School (UMMS), who gained new insights into autophagy - a cellular degradation process associated with a form of programmed cell death - by studying the salivary gland cells of the fruit fly.
Since its initial discovery in the 1960s, programmed cell death has been a primary focus of studies for investigators across a wide array of scientific disciplines. An essential mechanism in development and homeostasis, programmed cell death allows for the clean intracellular destruction of unnecessary or damaged cells. While apoptosis is the most understood type of programmed cell death, recently scientists have begun to take a closer look at autophagy— a highly regulated, catabolic process that essentially allows a cell to eat itself. Paradoxically, autophagy is not only a major mechanism by which a starving cell reallocates nutrients to ensure survival, scientists are now demonstrating that autophagy also provides cells that cannot undergo apoptosis with an alternate form of self-destruction.
In “Growth arrest and autophagy are required for salivary gland cell degradation in Drosophila,” published in the December 14 issue of Cell, Eric Baehrecke, PhD, UMMS Associate Professor of Cancer Biology, and colleagues examined fly salivary glands, which contain all of the machinery required to dismantle and recycle their own cellular components and thus provide a genetic model system for elucidating the complex functions of autophagy. The paper describes the cellular components required for autophagic cell death and defines multiple pathways that cooperate in the clearance of cells during fly development. Further, their findings demonstrate a critical relationship between growth and this form of cell death.