SLC51A encodes OSTα (organic solute transporter alpha), an essential component of the OSTα-OSTβ heterodimeric transporter complex that serves as the primary intestinal basolateral bile acid export mechanism 1. The functional transporter requires heterodimerization of OSTα (encoded by SLC51A) with OSTβ (encoded by SLC51B) for proper protein stability, post-translational modification, and plasma membrane delivery 1. This transporter operates via facilitated diffusion and can mediate bidirectional transport depending on electrochemical gradients 1. Beyond bile acids, the complex transports conjugated steroids and structurally-related molecules across basolateral membranes of epithelial cells, playing a central role in intestinal bile acid absorption and dietary lipid absorption 1. SLC51A expression is regulated by farnesoid X receptor (FXR), with activated FXR directly binding to SLC51A promoter regions 2. Clinical significance includes associations with progressive familial intrahepatic cholestasis type 6, with pathogenic SLC51A mutations identified in Pakistani pediatric cholestasis patients 3. The transporter also shows age-dependent expression patterns in human seminal vesicles 4 and responds to therapeutic bile acid treatments in preventing cholestasis 5.