Additionally, shared orthogroups in the ubiquitination system imply its importance during viral infection of protists: ubiquitin-conjugating enzyme E2 (13) and ubiquitin carboxyl-terminal hydrolase (105) in algal viruses (also in Megamimivirinae) (Fig. 5C) and ubiquitin-activating enzyme E1 (777) in the amoebal shared list (Supplementary Table S4). Here, UBE2S is linked to viral infectious disease.