Fig. 2. Recognition of the apoptotic cell and subsequent engulfment utilize a host of evolutionarily conserved proteins. (A) Some of the cell surface receptors on phagocytes that mediate the recognition of ligands (eat-me signals) on apoptotic cells and potentially lead to induction of anti-inflammatory mediators. Not all of the receptors need to be expressed or utilized by a phagocyte. Current evidence suggests that a subset of these receptors may engage a subset of the ligands on an apoptotic cell, which is sufficient to generate the signals necessary for the engulfment of the corpse. (B) Intracellular signaling driving extension of the phagocyte around the apoptotic cell involves two potentially redundant, evolutionarily conserved pathways consisting of CED-1/LRP, CED-6/GULP and UNC-73/Trio, MIG-2/RhoG, CED-2/CrkII, CED-5/Dock180, CED-12/ELMO, which may function coordinately in the regulation of CED-10/Rac1 activation.