SLC51 family of steroid-derived molecule transporters (version 2019.4) in the IUPHAR/BPS Guide to Pharmacology Database

Abstract

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 [1, 3]. OSTα/OSTβ is also expressed in steroidogenic cells of the brain and adrenal gland, where it may contribute to steroid movement [4]. Bile acid transport is suggested to be facilitative and independent of sodium, potassium, chloride ions or protons [3, 1]. 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 [1, 3, 4]. OSTα/OSTβ-mediated transport of bile salts is inhibited by clofazimine [7]. 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 [5]. Both proteins function in solute transport and bimolecular fluorescence complementation studies suggest the possibility of OSTα homo-oligomers, as well as OSTα/OSTβ hetero-oligomers [5, 2]. An inherited mutation in OSTβ is associated with congenital diarrhea in children [6].