Posttranslational modification of proteins is a prevalent method for the
regulation of cells according to changes in the surrounding environment and
diversifications. Pupylation, architecturally similar but not homologous to eukaryotic
proteasomal degradation machinery, exists in a certain order of bacteria, especially
actinobacteria. Pupylation supports the bacteria to survive under challenging
environmental conditions like stress (physical or chemical) and nutrient starvation.
Pupylation is also involved in iron homeostasis, which is necessary for cellular
metabolism and the normal growth of bacteria. Pupylation is a posttranslational
modification through which intrinsically disordered proteins are tagged for proteasomal
degradation. Although this process is functionally reminiscent of ubiquitination in
eukaryotes; it is carried out by a different set of enzymes in evolutionarily connected
bacterial carboxylate-amine ligases. In this chapter, we will discuss the recent advances
in the understanding of how proteins are tagged for proteasomal degradation in
actinobacteria and its role in the survival of mycobacterium during pathogenesis in the
host. Furthermore, we will examine the role of accessory factors associated with the
proteasomal system in bacteria that function independently of proteolysis.
Keywords: Mpa (Mycobacterial proteasomal ATPase) and Dop (Deamidase of
Pup), Mycobacterium, Proteasome, Pup, Pupylation.
