Phagocytosis

Phagocytosis is how eukaryotic cells take in large particles: microbes, dead or dying cells, aged red cells and debris. A receptor on the phagocyte recognises the particle, Rho-family GTPases drive actin to wrap the membrane around it, and the sealed phagosome then matures by fusing with endosomes and lysosomes into an acidic, degradative phagolysosome. There the cargo is digested and its products are returned to the cytosol. Protists use this route to feed; animal phagocytes use it for defence and for clearing cells. In animals, the digested cargo can also switch on programmes in the phagocyte itself, such as proliferation, priming, differentiation or an anti-inflammatory response, that depend on what was eaten.

This is an umbrella module. Each step is a separate module, included by reference. The first three steps are the phagocytic pathway itself and are shared by eukaryotes. The post-phagocytic programmes are optional and lineage-specific: each is triggered by a particular kind of cargo and has so far been shown in one animal lineage. In GO, GO:0006909 phagocytosis includes phagosome maturation (part_of since go-ontology#32152). The post-phagocytic programmes have no GO home; specific terms were proposed in go-ontology#32748. See projects/PHAGOCYTOSIS.md.