The amoebaDictyostelium discoideumis an established model to study phagocytosis. The sequence of events leading to the internalization and degradation of a particle is conserved inD. discoideumcompared to metazoan cells. As its small haploid genome has been sequenced, it is now amenable to genome-wide analysis including organelle proteomics. Therefore, we adapted toDictyosteliumthe classical protocol to purify phagosomes formed by ingestion of latex beads particles. The pulse-chase protocol detailed here gives easy access to pure, intact, and synchronized phagosomes from representative stages of the entire process of phagosome maturation. Recently, this protocol was used to generate individual temporal profiles of proteins and lipids during phagosome maturation generating a proteomic fingerprint of six maturation stages (1). In addition, immunolabeling of phagosomes on a coverslip was developed to visualize and quantitate antigen distribution at the level of individual phagosomes.
