Molecular Functions of Ubiquitin-like Modifiers in Bacterial Infection

Ubiquitin-like proteins (UBLs) such as SUMO, NEDD8, ISG15, FAT10, and UFM1 are proteins that share structural similarities to ubiquitin. Like ubiquitin, they function as protein modifiers, catalyzing modifications through a conserved enzymatic cascade of E1 activating enzymes, E2 conjugating enzymes, and E3 ligases. In doing so, UBLs regulate a diverse set of cellular processes, including stress response, antiviral activity, nuclear transport, cancer development, and autophagy. In recent years, the roles of UBLs during pathogenic bacteria infection have gained attention, although much still remains elusive. This review describes current findings related to UBL systems in the context of pathogenic bacteria infection, focusing on NEDD8, ISG15, FAT10, and UFM1. Specifically, we look at how the host UBL system responds to bacterial infection by inducing the host's defense system, and how pathogenic bacteria manipulate the host UBL system to ensure successful infection.