Retromer Is Required for Apoptotic Cell Clearance by Phagocytic Receptor Recycling

Corpse-Sorting Machinery Phagocytosis of apoptotic cells is an integral part of the cell death program and plays critical roles in tissue remodeling, suppression of inflammation, and regulation of immune responses. The clearance of cell corpses requires their engulfment and subsequent degradation by phagocytic cells. During this process, receptors of the CED-1 family play a central role in recognizing cell corpses, transducing engulfment signals, and initiating the maturation of phagosomes containing apoptotic cell corpses. Retromer is a multisubunit protein complex conserved from yeast to mammals that mediates retrograde transport of transmembrane cargo from the endosome to the trans-Golgi network. Failure in recycling these proteins leads to their delivery to lysosomes where they are degraded. Chen et al. (p. 1261 , published online 4 February) report that the Caenorhabditis elegans retromer complex is essential for the phagocytosis of CED-1 and thus for the clearance of apoptotic cells.