Organic Solute Transporter beta Proteine (OSTBETA)

Human Organic Solute Transporter beta (OSTBETA) Interaktionspartner

1. Dileucine motif in the extracellular N-terminal region is essential for OSTB plasma membrane targeting.

2. Hepatic OSTalpha-OSTbeta expression is induced by hypoxia.

3. OSTbeta is a target of RARalpha-mediated (by binding to DR5 response element) gene regulation pathways

4. Ostbeta is required for both proper trafficking of Ostalpha and formation of the functional transport unit, and identify specific residues of Ostbeta critical for these processes.

5. The present report summarizes the evidence for a pleiotropic role of Ostalpha-Ostbeta in different tissues.

6. OSTbeta is localized to steroidogenic cells of the brain and adrenal gland, and it modulates DHEA/DHEAS homeostasis

7. OSTbeta has roles in biological transport and is widely expressed in human tissues

8. overexpression of human OSTalpha and OSTbeta facilitated the uptake of conjugated chenodeoxycholate and the activation of FXR target genes

9. OSTalpha/OSTbeta expression is induced by bile acids through ligand-dependent transactivation of both OST genes by the nuclear bile acid receptor/farnesoid X receptor (FXR).

10. the selective localization of OSTalpha and OSTbeta to the basolateral plasma membrane of epithelial cells responsible for bile acid and sterol reabsorption.

11. These results indicate that expression of Ostalpha and Ostbeta are highly regulated in response to cholestasis and that this response is dependent on the FXR bile acid receptor.

12. Demonstrate association of OST-alpha and OST-beta to determine trafficking to plasma membrane and activity.

13. The mRNA expression of OSTalpha-OSTbeta was significantly reduced (OSTalpha: 3.3-fold, P = 0.006; OSTbeta: 2.6-fold, P = 0.03) in normal-weight but not overweight gallstone carriers

14. interaction of solute transporter beta with human organic solute transporter alpha.

Mouse (Murine) Organic Solute Transporter beta (OSTBETA) Interaktionspartner

1. Data suggest that transport of bile acid taurocholate is retained when OstB is truncated to contain only the transmembrane domain with 15 additional residues on each side and co-expressed with intact OstA (organic solute transporter alpha subunit); shorter fragments of OstB are inactive.

2. Co-expression of mouse Ostalpha-Ostbeta, but not the individual subunits, stimulated Na(+)-independent bile acid uptake and the apical-to-basolateral transport of taurocholate

3. OSTalpha and OSTbeta mRNA levels were induced in the adrenals and kidneys of wild-type, but not FXR-/-, mice

4. the selective localization of OSTalpha and OSTbeta to the basolateral plasma membrane of epithelial cells responsible for bile acid and sterol reabsorption.

5. In conclusion, we identified Ost-alpha/Ost-beta as a novel FXR target. Absent Ost-alpha/Ost-beta induction in CA-fed FXR(-/-) animals may contribute to increased liver injury in these animals.

6. The mouse Ostalpha and Ostbeta promoters are unusual in that they contain functional FXR and LRH elements, which mediate, respectively, positive and negative feedback regulation by bile acids.

7. These results indicate that expression of Ostalpha and Ostbeta are highly regulated in response to cholestasis and that this response is dependent on the FXR bile acid receptor.

8. LXRalpha transcriptionally regulate mouse organic solute transporter alpha/beta via inverted repeat-1 elements shared with farnesoid X receptor

9. Present as heterodimers (with Ost alpha) and/or heteromultimers; the interaction between Ostalpha and Ostbeta increases the stability of the proteins and is required for delivery of the heteromeric complex to the plasma membrane.

10. These data indicate that Ostalpha-Ostbeta is essential for intestinal bile acid transport in mice.

11. These findings provide direct support for the hypothesis that Ostalpha-Ostbeta is a major basolateral transporter of bile acids and conjugated steroids in the intestine, kidney, and liver.