Clearance of apoptotic corpses

Apoptotic corpses can be engulfed and cleared by many other cell types in addition to 'professional' phagocytes such as macrophage. Studies of several organisms have contributed to the understanding of apoptotic corpse engulfment. Two partially redundant engulfment pathways have been characterized that act even in non-professional phagocytes to promote corpse engulfment. This review summarizes some recent progress in signaling by these pathways, including the exposure of eat-me-signals on apoptotic cells, and insights from Drosophila on the roles of the bridging receptor Six Microns Under, the non-receptor tyrosine kinase Shark, and store-operated calcium release in the Draper/Ced-1 pathway of corpse recognition and internalization. The mechanism of apoptotic phagosome maturation is outlined, and possible connections between corpse engulfment and proliferation, cell competition, and immunity are discussed.