Signaling of Phagocytosis

Phagocytosis, the process whereby cells ingest large particles (>0.5 μm), is essential for innate immunity and for clearance of effete cells. Its dysregulation can cause infectious or autoimmune diseases. Initiation of phagocytosis occurs at the cell surface, where multivalent particulate targets engage cognate receptors. When clustered, phagocytic receptors generate signals that elicit the actin-dependent engulfment of the particle. A multitude of distinct phagocytic receptors exist, and the mechanisms whereby individual receptor types recognize suitable prey and the signals they generate can vary significantly. In this article, salient examples of phagocytic receptors are discussed, as are the downstream signal transduction cascades that mediate phagosome formation.