Members of this family adopt a Cdc48 domain 2-like fold, with a beta-alpha-beta(3) arrangement. It has been suggested that this domain may be involved in interactions with ubiquitin, ubiquitin-like protein modifiers, or ubiquitin-like domains, such as Ubx. Furthermore, the domain may possess a putative adaptor or substrate binding site, allowing for peroxisomal biogenesis, membrane fusion and protein translocation [1].

1: Structure of the N-terminal domain of PEX1 AAA-ATPase. Characterization of a putative adaptor-binding domain. Shiozawa K, Maita N, Tomii K, Seto A, Goda N, Akiyama Y, Shimizu T, Shirakawa M, Hiroaki H; J Biol Chem. 2004;279:50060-50068. PMID:15328346