Versatility of USP18 in physiology and pathophysiology.

Ubiquitin-specific peptidase 18 (USP18) is a multifunctional protein and its roles are still being investigated. This enzyme removes ubiquitin-like molecules from their substrates and the only known interferon-stimulated gene 15 (ISG15) specific protease. Apart from its enzymatic function, it also inhibits interferon type I and III signalling pathways. USP18 is known to regulate multiple processes, such as: cell cycle, cell signalling and response to viral and bacterial infections. Moreover, it contributes to the development of several autoimmune diseases and carcinogenesis, and recently was described as a cardiac remodelling inhibitor. This review summarizes the current knowledge on USP18 functions, highlighting its contribution to the development of heart failure, given the fact that this disease's etiology is now considered to be inflammatory in nature.