Deubiquitinating enzymes as novel anticancer targets

Ubiquitin ligases as therapeutic targets in HIV-1 infection

BACKGROUND

Introduction of highly active antiretroviral therapy has led to a profound reduction in human immunodeficiency virus (HIV) related mortality; although, the complete eradication of the virus from infected individuals has never been achieved. In addition, due to the high mutation and evolution rate, drug-resistant viruses are continuously emerging.

OBJECTIVE

Genetically more stable cellular pathways represent attractive targets for innovative antiviral strategies, especially the ubiquitin proteasome system, which regulates various steps in the HIV replication cycle.

METHODS

This review focuses on certain interactions of HIV and E3 ligases as a major player in the ubiquitin proteasome system.

RESULTS/CONCLUSION

Due to the importance in HIV replication, and together with the high substrate specificity, E3 ligases can be considered as bona fide targets to interfere with HIV infection.

Mechanisms, biology and inhibitors of deubiquitinating enzymes

The addition of ubiquitin (Ub) and ubiquitin-like (Ubl) modifiers to proteins serves to modulate function and is a key step in protein degradation, epigenetic modification and intracellular localization. Deubiquitinating enzymes and Ubl-specific proteases, the proteins responsible for the removal of Ub and Ubls, act as an additional level of control over the ubiquitin-proteasome system. Their conservation and widespread occurrence in eukaryotes, prokaryotes and viruses shows that these proteases constitute an essential class of enzymes. Here, we discuss how chemical tools, including activity-based probes and suicide inhibitors, have enabled (i) discovery of deubiquitinating enzymes, (ii) their functional profiling, crystallographic characterization and mechanistic classification and (iii) development of molecules for therapeutic purposes.