Phagocytosis: a process that shapes immune responses to engulfed meals

The process of phagocytosis creates intracellular compartments (organelles known as phagosomes) that are central hubs for innate immune sensing of potentially dangerous microorganisms, cells, cellular debris and foreign objects. Receptors, enzymes and signalling molecules are specifically enriched in these compartments, wherein they learn everything they can about the phagocytosed material and signal for the cell to mount appropriate responses. The phagosome organelle is also a compartment that facilitates nutrient and metabolite harvesting from internalized materials. This Review explores recent developments in our understanding of phagocytosis as a specific mechanism of innate immune sensing. We discuss efforts to identify the catalogue of proteins that are enriched in different types of phagosomes to learn how these molecules work together to tailor inflammatory and antimicrobial immune responses.