In eukaryotes, ubiquitin and other ubiquitin like (Ub/UBL) modifications share a similar three step thioester cascade process catalyzed by E1s (ubiquitin activating enzymes), E2s (ubiquitin conjugating enzymes) and E3s (ubiquitin protein ligases) (Kerscher et al., 2006). The process of Ub/UBL conjugation is reversed by DUBs (deubiquitinating enzymes), which could remove the Ub/UBL from modified proteins (Nijman et al., 2005; Reyes Turcu et al., 2009). Moreover, UBDs (ubiquitin binding domain containing proteins) can selectively recognize monoubiquitin and ubiquitin chains with different linkages and lengths to control various cellular functions in vivo (Husnjak et al., 2012). Besides, ULDs (ubiquitin like domains) are also identified as important integral elements of a large variety of protein families (Upadhya et al., 2003). Owe to the complexity of ubiquitin signal formation and its corresponding recognition mechanism, ubiquitination performs various cellular and physiological functions.