The nascent polypeptide-associated complex (NAC), consisting of alpha and beta subunits, is an essential ribosome-associated protein conserved in eukaryotes. It is a ubiquitously expressed co-translational regulator of nascent protein folding and sorting. Drosophila species, at least, have multiple alpha and beta subunit paralogs, some of which are expressed specifically in the germline and combine to form a germinal NAC. (Adapted from FBrf0253862.)