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+. Also in the family is ARC3 from S. cerevisiae; this is a putative transmembrane protein involved in resistance to arsenic compounds.
Jiyao W et al.(2023). "The conserved domain database in 2023.",