This family consists of Na+/bile acid co-transporters. These transmembrane proteins function in the liver in the uptake of bile acids from portal blood plasma a process mediated by the co-transport of Na+ [2]. Also in the family is ARC3 from S. cerevisiae Swiss:Q06598 this is a putative transmembrane protein involved in resistance to arsenic compounds [1].

1: Isolation of three contiguous genes, ACR1, ACR2 and ACR3, involved in resistance to arsenic compounds in the yeast Saccharomyces cerevisiae. Bobrowicz P, Wysocki R, Owsianik G, Goffeau A, Ulaszewski S; Yeast 1997;13:819-828. PMID:9234670

2: Functional expression cloning and characterization of the hepatocyte Na+/bile acid cotransport system. Hagenbuch B, Stieger B, Foguet M, Lubbert H, Meier PJ; Proc Natl Acad Sci U S A 1991;88:10629-10633. PMID:1961729