Ubiquitin-like proteins fall into two classes: the first class, ubiquitin-like modifiers (UBLs) function as modifiers in a manner analogous to that of ubiquitin. Examples of UBLs are SUMO, Rub1 (also called Nedd8), Apg8 and Apg12. Proteins of the second class include parkin, RAD23 and DSK2, are designated ubiquitin-domain proteins (UDPs). These proteins contain domains that are related to ubiquitin but are otherwise unrelated to each other. In contrast to UBLs, UDPs are not conjugated to other proteins. Hub1 (''Homologous to UBiquitin'') may function as a modifier (see figure 2) but its role is unclear because it lacks the double glycine motif characteristic for ubiquitin and ubiquitin-like modifiers. Recently cell polarity factors Sph1 and Hbt1 have been identified as in vivo targets of Hub1 conjugation.
Synonyms: Homologous to UBiquitin antibody, Hub1 protein antibody, HUB1 target protein 1 antibody, Hub1p antibody, Ubiquitin like protein modifier antibody