Mycobacterium tuberculosis-specific phagosome proteome and underlying signaling pathways

The phagosome is very important to host immunity and tissue homeostasis maintenance. The destiny of the phagosome is closely associated with the outcome of the pathogen within. Most pathogens are successfully delivered to the lysosome and destroyed via the fusion of the phagosome with the lysosome. Mycobacterium tuberculosis has evolved multiple tactics to deflect the normal fusion process, such as delaying the phagosome maturation and acidification, thereby evading the immune recognition and subsequent elimination. Identification of the specific constituents of M. tuberculosis phagosome and the underlying signaling pathways are pivotal to define the key molecular features of this process and better targets to control this recalcitrant pathogen. Proteomic profiling is a comprehensive approach to define the protein inventory. In this review, currently available mycobacteria-containing phagosome proteome data were compiled. Ten putative evolutionarily conserved phagosome proteins were summarized. Unique proteins of the M. tuberculosis-containing phagosome proteome were compiled via comparison with other phagosomes, especially the inert latex bead phagosome. Signaling events associated with these unique proteins, such as Rab GTPase and PI3P, were also found and discussed. The data will facilitate better characterization of the M. tuberculosis specific phagosome constituents and involved signaling, and host-derived targets for better tuberculosis control.