Abstract: Prokaryotic ubiquitin-like protein (Pup), a small protein alike to the ubiquitin in eukaryotes, exi-sts in mycobacterium. When targeted by the Pup, the proteins are degraded by the proteasome or become regulators after the modification. Thus, it can influence all activities of the cells. Currently, 58 population proteins, which can be targeted by Pup, have been identified in Mycobacterium tuberculosis (Mtb); in Mycobacterium smegmatis, it has been identified that 41 population proteins can be targeted by Pup, and the orthologous genes of 38 out of 41 population proteins can be found in Mtb genome. Those target proteins have been involved in at least 6 mechanisms and functions in the activities of the cells, including the virulence of mycobacterium, information pathway, lipid metabolism, cell wall and/or membrane synthesis, and intermediary metabolism, etc. After targeted, most of the population proteins are degrated by the proteasome and only a few of them are involved in the signal transmissions and re-gulations. Through comparisons and analysis of the target proteins, the further explanations can be made for the mechanisms of Mtb drug-resistance development and pathopoiesis; at the same time, the proteins targeted by Pup can be the potential drug targets, which provides the theory foundations for the TB treatment and control.

Key words: Mycobacterium, Ubiquitins, Proteasome endopeptidase complex