摘要：

This chapter addresses the vesicular trafficking events involved in the formation and maturation of the phagosome. The reported increase in surface area during phagocytosis is most readily explained by delivery of an internal pool of membranes to the plasmalemma. Recent studies demonstrated that specific and tertiary granules contain VAMP1 and VAMP2, while azurophilic granules contain VAMP1 and VAMP7, with STX4 and SNAP23 involved in the exocytosis of these distinct populations of granules. Lysobisphosphatidic acid (LBPA) is found in late phagosomes, where it is likely to complex ALIX and direct membrane fission and the intermediate stages of maturation. Phagosome formation and maturation are impressive microbicidal tools. For this reason pathogens have developed a remarkable variety of strategies to subvert this process. Some of the most virulent and persistent bacterial pathogens such as Mycobacterium and Leishmania in fact take advantage of the phagocytic machinery to gain access into the host cell interior, where they are able to circumvent the sophisticated killing mechanism of the maturing phagosome. At present the knowledge of phagosome maturation is rudimentary and largely extrapolated from that garnered for the endocytic pathway. Some extrapolation is probably warranted, but many unique features of phagosomes will only be revealed by direct studies of particle, preferably microbial, ingestion.

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