This protein family is paralogous to (and distinct from) the PafA (proteasome accessory factor) first described in Mycobacterium tuberculosis (see TIGR03686). Members of both this family and TIGR03686 itself tend to cluster with each other, with the ubiquitin analog Pup (TIGR03687) associated with targeting to the proteasome, and with proteasome subunits themselves. [Protein fate, Degradation of proteins, peptides, and glycopeptides]
Jiyao W et al.(2023). "The conserved domain database in 2023.",