Members of this family are integral membrane proteins that are involved in transport of nicotinamide mononucleotide [1,2].

1: Regulation of NAD metabolism in Salmonella typhimurium: molecular sequence analysis of the bifunctional nadR regulator and the nadA-pnuC operon. Foster JW, Park YK, Penfound T, Fenger T, Spector MP; J Bacteriol 1990;172:4187-4196. PMID:2198247

2: Genetic characterization of the pnuC gene, which encodes a component of the nicotinamide mononucleotide transport system in Salmonella typhimurium. Zhu N, Olivera BM, Roth JR; J Bacteriol 1989;171:4402-4409. PMID:2546921