<i>Mycobacterium tuberculosis</i>-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.