Ubiquitin-like proteins (UBLs) include ubiquitin and other evolutionarily related proteins that share the ubiquitin fold and the capacity to be conjugated to substrates through a cascade of E1 activating enzymes, E2 conjugating enzymes, and E3 ligases. Conjugation of UBLs to target proteins or lipids regulate their activity, stability, subcellular localization, or macromolecular interactions. (Adapted from PMID:28234446.)
Notes on Group
D. melanogaster lacks homologs of the mammalian Ubiquitin-like proteins FAT10 and ISG15.