SLC51A Membrane Protein Introduction

Introduction of SLC51A

SLC51A (OSTα) encoded by SLC51A gene, also known as OSTα, is a predicted 340-amino acid, 7-transmembrane (TM) domain protein. It combines with SLC51B (OSTβ) and forms a functional heterodimeric transporter, designated as OSTα-OSTβ. The organic solute transporter OSTα-OSTβ is expressed at the basolateral membrane of epithelium in intestine, kidney, liver, testis, and adrenal gland and involved in the mediation of bile acids efflux.

Basic Information of SLC51A
Protein Name Organic solute transporter subunit alpha
Gene Name SLC51A
Aliases OSTA, OSTalpha
Organism Homo sapiens (Human)
UniProt ID Q86UW1
Transmembrane Times 1
Length (aa) 128

Function of SLC51A Membrane Protein

SLC51A (OSTalpha) is an essential component of the Ost-alpha/Ost-beta heterodimer complex that functions as the intestinal basolateral transporter mediating bile acid export from enterocytes into portal blood. And it is essential for intestinal bile acid absorption, and thus for dietary lipid absorption. Besides, OSTα-OSTβ plays a central role in the transport of conjugated steroids and structurally-related molecules across the basolateral membrane of many epithelial cells. Moreover, the mechanism of OSTα-OSTβ transporter is a facilitated diffusion and transporter can mediate either efflux or uptake depending on the electrochemical gradient of its substrates. Studies have indicated that OSTα/β is an important transporter in liver disease, implying a role for this transporter in bile acid-bile acid and drug-bile acid interactions, as well as cholestatic drug-induced liver injury. The elevated expression of OSTα/β is observed in the liver of patients with nonalcoholic steatohepatitis and primary biliary cholangitis.

Transcriptional regulation of transporters participating in the enterohepatic circulation of bile acids. Fig.1 Transcriptional regulation of transporters participating in the enterohepatic circulation of bile acids. (Ballatori, 2013)

Application of SLC51A Membrane Protein in Literature

  1. Wang Y. and Tatakis D.N. Human gingiva transcriptome during wound healing. Journal of Clinical Periodontology. 2017, 44(4): 394-402. PubMed ID: 28005267

    The article demonstrates that SLC51A expression is significantly increased in human masticatory mucosa during wound healing.

  2. Soroka C.J., et al. N-Glycosylation of the alpha subunit does not influence trafficking or functional activity of the human organic solute transporter alpha/beta. BMC Cell Biology. 2008, 9: 57. PubMed ID: 18847488

    The study reveals that human OSTalpha is a glycoprotein that requires interaction with OSTbeta to reach the plasma membrane. However, glycosylation of OSTalpha is not required for interaction with the beta subunit or for membrane localization or function of the heteromeric transporter.

  3. Renner O., et al. Reduced ileal expression of OSTalpha-OSTbeta in non-obese gallstone disease. Journal of Lipid Research. 2008, 49(9): 2045-54. PubMed ID: 18469300

    The experimental data suggest that the mRNA expression of OSTalpha-OSTbeta is significantly decreased in normal-weight but not overweight gallstone carriers.

  4. Sun A.Q., et al. Protein-protein interactions and membrane localization of the human organic solute transporter. American Journal of Physiology Gastrointestinal & Liver Physiology. 2007, 292(6): G1586-93. PubMed ID: 17332473

    In this study, authors demonstrate the association of OST-alpha and OST-beta to determine trafficking to plasma membrane and activity.

  5. Boyer J.L., et al. Upregulation of a basolateral FXR-dependent bile acid efflux transporter OSTalpha-OSTbeta in cholestasis in humans and rodents. American Journal of Physiology Gastrointestinal & Liver Physiology. 2006, 290(6): G1124-30. PubMed ID: 16423920

    The article indicates that the expression of Ostalpha and Ostbeta are significantly upregulated in response to cholestasis and that this response depends on the FXR bile acid receptor.

SLC51A Preparation Options

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  1. Ballatori N, et al. (2013). The heteromeric organic solute transporter, OSTα–OSTβ/SLC51: A transporter for steroid-derived molecules. Molecular Aspects of Medicine. 34(2-3), 683-692.

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