Citation

  • Authors: Davis, LC., et al.
  • Year: 2020
  • Journal: EMBO J. 39 e104058
  • Applications: in vitro / DNA / jetPRIME
  • Cell types:
    1. Name: Mouse bone marrow-derived macrophages
      Description: Primary mouse bone marrow macrophages
      Known as: BMDM
    2. Name: RAW 264.7
      Description: Mouse monocytes/macrophages
      Known as: RAW

Abstract

Macrophages clear pathogens by phagocytosis and lysosomes that fuse with phagosomes are traditionally regarded as to a source of membranes and luminal degradative enzymes. Here, we reveal that endo-lysosomes act as platforms for a new phagocytic signalling pathway in which FcγR activation recruits the second messenger NAADP and thereby promotes the opening of Ca2+ -permeable two-pore channels (TPCs). Remarkably, phagocytosis is driven by these local endo-lysosomal Ca2+ nanodomains rather than global cytoplasmic or ER Ca2+ signals. Motile endolysosomes contact nascent phagosomes to promote phagocytosis, whereas endo-lysosome immobilization prevents it. We show that TPC-released Ca2+ rapidly activates calcineurin, which in turn dephosphorylates and activates the GTPase dynamin-2. Finally, we find that different endo-lysosomal Ca2+ channels play diverse roles, with TPCs providing a universal phagocytic signal for a wide range of particles and TRPML1 being only required for phagocytosis of large targets.

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