PAC1 is a family of eukaryotic proteasome assembly chaperone 1 proteins in eukaryotes that promotes assembly of the core 20S proteasome as part of a heterodimer with PAC2.

1: 20S proteasome assembly is orchestrated by two distinct pairs of chaperones in yeast and in mammals. Le Tallec B, Barrault MB, Courbeyrette R, Guerois R, Marsolier-Kergoat MC, Peyroche A; Mol Cell. 2007;27:660-674. PMID:17707236