This family of eukaryotic aspartyl proteases have a fold similar to retroviral proteases which implies they function proteolytically during regulated protein turnover [1].

1: Ddi1, a eukaryotic protein with the retroviral protease fold. Sirkis R, Gerst JE, Fass D; J Mol Biol. 2006;364:376-387. PMID:17010377