This entry includes Organic solute transporter subunit alpha (OSTalpha, also known as SLC51A) and Transmembrane protein 184 (TMEM184). Ost-alpha protein is a 7-transmembrane (TM) domain containing protein that forms a transporter complex with Ost-beta protein, which is a single-TM domain polypeptide. This heterodimerisation is required for the delivery of the complex to the plasma membrane. The OSTalpha-OSTbeta complex serves as a multispecific transporter that may participate in cellular uptake of bile acids, some endogenous and exogenous steroids, and eicosanoids. It functions via a facilitated diffusion mechanism. Interestingly, this transporter also transports dehydroepiandrosterone sulfate (DHEAS) and pregnenolone sulfate (PREGS), which are major excitatory neurosteroids. This suggests a possible function for OSTalpha-OSTbeta complex in the brain []. In plants this complex may transport brassinosteroid-like compounds and act as regulators of cell death [].Human TMEM184C is a possible tumour suppressor which may play a role in cell growth []. This entry also includes Arabidopsis protein LAZ1, which is required for programmed cell death (PCD) associated with hypersensitive response (HR) [].
