SLC51 family of steroid-derived molecule transporters (version 2020.4) in the IUPHAR/BPS Guide to Pharmacology Database

The SLC51 organic solute transporter family of transporters is a pair of heterodimeric proteins which regulate bile salt movements in the small intestine, bile duct, and liver, as part of the enterohepatic circulation [2, 4, 1]. OSTα/OSTβ is also expressed in steroidogenic cells of the brain and adrenal gland, where it may contribute to steroid movement [5]. Bile acid transport is suggested to be facilitative and independent of sodium, potassium, chloride ions or protons [4, 2]. OSTα/OSTβ heterodimers have been shown to transport [3H]taurocholic acid, [3H]dehydroepiandrosterone sulphate, [3H]estrone-3-sulphate, [3H]pregnenolone sulphate and [3H]dehydroepiandrosterone sulphate [2, 4, 5]. OSTα/OSTβ-mediated transport of bile salts is inhibited by clofazimine [9]. OSTα is suggested to be a seven TM protein, while OSTβ is a single TM 'ancillary' protein, both of which are thought to have intracellular C-termini [7]. Both proteins function in solute transport [7, 3]. Inherited mutations in OSTα and OSTβ are associated liver disease and congenital diarrhea in children [8, 6].