Nas2 is a proteosome assembly chaperone. Nas2 bivalently binds the proteasome Rpt5 subunit. The Nas2 N-terminal helical domain masks the Rpt1-interacting surface of Rpt5 [1].

1: Structural basis for proteasome formation controlled by an assembly chaperone nas2. Satoh T, Saeki Y, Hiromoto T, Wang YH, Uekusa Y, Yagi H, Yoshihara H, Yagi-Utsumi M, Mizushima T, Tanaka K, Kato K; Structure. 2014;22:731-743. PMID:24685148