Nature: identification of a new molecular mechanism of inhibition of host immunity by Mycobacterium tuberculosis

January 18, 2020 / BIOON / -- recently, in a research report titled "host mediated ubiquitination of a mycobacterial protein suppresses immunity" published in the international journal Nature, scientists from the Medical College of Tongji University of China and other institutions found that host mediated mycobacterial protein ubiquitination may inhibit the immune system Photo source: en.wikipedia.org Mycobacterium Tuberculosis) is a kind of intracellular pathogenic bacteria, which can use many strategies to interfere with the signal transmission function of host immune molecules At present, researchers have found that many pathogenic bacteria can use the host's own ubiquitination system to promote the pathogenesis, but researchers do not know whether the same system will regulate the ubiquitination of Mycobacterium tuberculosis protein In this study, the researchers reported a host organism called E3 ubiquitin ligase anapc2, which is a core subunit of late cell division promoting complex / cell cycle body It can interact with mycobacterial protein rv0222 and promote the ubiquitin chain connected with lysine-11 to adsorb at lysine 76 of rv0222, thus inhibiting the expression of proinflammatory cytokines Inhibition of anapc2 function by short stranded hairpin RNA may remove the inhibitory effect of rv0222 on pro-inflammatory response In addition, the researchers also found that the mutation of ubiquitination site on rv0222 may damage the inhibition of inflammatory cytokines mediated by rv0222 and reduce bacteria during mouse infection Virulence: anapc2 mediated ubiquitination of rv0222 lysine-11 linkage can promote the recruitment of tyrosine phosphatase SHP1 to the adaptor protein TRAF6, thus inhibiting the ubiquitination and activation of the lysine-63 linkage of TRAF6 Finally, the researchers said that in this study, they have identified a new mechanism that has not been found before, that is, the special mechanism of how Mycobacterium tuberculosis suppresses the host's immune system The relevant research results may help researchers to develop new and effective immunomodulators later to target Mycobacterium tuberculosis Original source: Wang, L., Wu, J., Li, J et al Host mediated ubiquity of a Mycobacterium protein suppresses immunity Nature (2020) doi: 10.1038/s41586-019-1915-7