Protein ubiquitination is a conserved post-translational modification, which is related to the proteasome-dependent protein degradation and many other processes in a non-proteolytic pathway [1]. Ubiquitination-mediated protein degradation regulates various cellular processes, including cell proliferation, differentiation, apoptosis, migration, and invasion [2]. Abnormal ubiquitination is associated with the pathogenesis of various diseases, such as cancer and neurodegenerative disorders [3].
