Differential recruitment of CD63 and Rab7-interacting-lysosomal-protein to phagosomes containing Mycobacterium tuberculosis in macrophages

M.tb is an intracellular pathogen which survives within the phagosomes of host macrophages by inhibiting their fusion with lysosomes. Here, it has been demonstrated that a lysosomal glycoprotein, CD63, is recruited to the majority of M.tb phagosomes, while RILP shows limited localization. This is consistent with the author's findings that CD63, but not RILP, is recruited to the phagosomes in macrophages expressing the dominant negative form of Rab7. These results suggest that M.tb phagosomes selectively fuse with endosomes and lysosomes to escape killing activity while acquiring nutrients.