UC Berkeley

During Mycobacterium tuberculosis infection, macrophages serve key functions as both a niche for bacterial growth and as potent inducers of inflammation to influence the outcome of M. tuberculosis infection. After macrophages phagocytose M. tuberculosis, the permeabilization of the phagosomal membrane by ESX-1 signals the start of a battle between antimicrobial host responses and subversion of these defenses by the bacteria. To further characterize the macrophage responses to the M. tuberculosis infection, we previously conducted a large post-translational modification (PTM) proteomics experiment that identified proteins modified in response to infection. Here I investigate a host protein, MYCBP2, that is ubiquitylated and phosphorylated during M. tuberculosis infection in primary macrophages. I found that MYCBP2 deficient macrophages are more susceptible to M. tuberculosis and express less inflammatory cytokines during infection and in response to stimulus via a p38 MAPK-dependent mechanism. I also provide the first evidence that MYCBP2 can regulate viral growth in macrophages. As a complementary approach to our PTM proteomics data, I used proximity-based labeling to identify host proteins recruited to the phagosomal membrane after membrane permeabilization. In this dissertation, I present multiple approaches to conducting proximity labeling experiments during M. tuberculosis infection and explore some proteins of interest arising from these datasets. Lastly, I explore the possible role of RNF213 in M. tuberculosis infection. This dissertation adds to our knowledge of how the macrophage responds to infection by M. tuberculosis.