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0  structures 44  species 0  interactions 49  sequences 2  architectures

Family: OSTbeta (PF15048)

Summary: Organic solute transporter subunit beta protein

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This is the Wikipedia entry entitled "OSTbeta". More...

OSTbeta Edit Wikipedia article

Solute carrier family 51, beta subunit
External IDs OMIM612085 MGI3582052 HomoloGene18721 GeneCards: SLC51B Gene
RNA expression pattern
PBB GE OSTbeta gnf1h06426 at tn.png
More reference expression data
Species Human Mouse
Entrez 123264 330962
Ensembl ENSG00000186198 ENSMUSG00000053862
UniProt Q86UW2 Q80WK2
RefSeq (mRNA) NM_178859 NM_178933
RefSeq (protein) NP_849190 NP_849264
Location (UCSC) Chr 15:
65.05 – 65.05 Mb
Chr 9:
65.41 – 65.42 Mb
PubMed search [1] [2]

Organic solute transporter beta, also known as OST-beta, is a protein which in humans is encoded by the OSTB gene.[1][2]


OST-beta together with OST-alpha is able to transport estrone sulfate, taurocholate, digoxin, and prostaglandin E2 across cell membranes.[2][3] The Ost-alpha / Ost-beta heterodimer, but not the individual subunits, stimulates sodium-independent bile acid uptake.[3] The heterodimer furthermore is essential for intestinal bile acid transport.[4]

OST-alpha and OST-alpha have high expression in the testis, colon, liver, small intestine, kidney, ovary, and adrenal gland.[2]


  1. ^ "Entrez Gene: OSTbeta organic solute transporter beta". 
  2. ^ a b c Seward DJ, Koh AS, Boyer JL, Ballatori N (July 2003). "Functional complementation between a novel mammalian polygenic transport complex and an evolutionarily ancient organic solute transporter, OSTalpha-OSTbeta". J. Biol. Chem. 278 (30): 27473–82. doi:10.1074/jbc.M301106200. PMID 12719432. 
  3. ^ a b Dawson PA, Hubbert M, Haywood J, Craddock AL, Zerangue N, Christian WV, Ballatori N (February 2005). "The Heteromeric Organic Solute Transporter α-β, Ostα-Ostβ, Is an Ileal Basolateral Bile Acid Transporter". J. Biol. Chem. 280 (8): 6960–8. doi:10.1074/jbc.M412752200. PMC 1224727. PMID 15563450. 
  4. ^ Rao A, Haywood J, Craddock AL, Belinsky MG, Kruh GD, Dawson PA (March 2008). "The organic solute transporter α-β, Ostα-Ostβ, is essential for intestinal bile acid transport and homeostasis". Proc. Natl. Acad. Sci. U.S.A. 105 (10): 3891–6. doi:10.1073/pnas.0712328105. PMC 2268840. PMID 18292224. 

Further reading

This page is based on a Wikipedia article. The text is available under the Creative Commons Attribution/Share-Alike License.

This tab holds the annotation information that is stored in the Pfam database. As we move to using Wikipedia as our main source of annotation, the contents of this tab will be gradually replaced by the Wikipedia tab.

Organic solute transporter subunit beta protein Provide feedback

No Pfam abstract.

Literature references

  1. Hwang JH, Parton A, Czechanski A, Ballatori N, Barnes D;, Comp Biochem Physiol C Toxicol Pharmacol. 2008;148:39-47.: Arachidonic acid-induced expression of the organic solute and steroid transporter-beta (Ost-beta) in a cartilaginous fish cell line. PUBMED:18407792 EPMC:18407792

  2. Dawson PA, Hubbert M, Haywood J, Craddock AL, Zerangue N, Christian WV, Ballatori N;, J Biol Chem. 2005;280:6960-6968.: The heteromeric organic solute transporter alpha-beta, Ostalpha-Ostbeta, is an ileal basolateral bile acid transporter. PUBMED:15563450 EPMC:15563450

  3. Frankenberg T, Rao A, Chen F, Haywood J, Shneider BL, Dawson PA;, Am J Physiol Gastrointest Liver Physiol. 2006;290:G912-G922.: Regulation of the mouse organic solute transporter alpha-beta, Ostalpha-Ostbeta, by bile acids. PUBMED:16357058 EPMC:16357058

This tab holds annotation information from the InterPro database.

InterPro entry IPR029387

Organic solute transporter subunit beta (OSTbeta, also known as SLC51B) is an essential component of the Ost-alpha/Ost-beta complex, a heterodimer that acts as the intestinal basolateral transporter responsible for bile acid export from enterocytes into portal blood [PUBMED:16317684].

OSTbeta is a single-TM domain polypeptide that forms a transporter complex with Ost-alpha protein, which is a 7-transmembrane (TM) domain containing protein. 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 [PUBMED:23506901].

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Seed source: Jackhmmer:Q86UW2
Previous IDs: none
Type: Family
Author: Bateman A
Number in seed: 19
Number in full: 49
Average length of the domain: 121.60 aa
Average identity of full alignment: 43 %
Average coverage of the sequence by the domain: 74.20 %

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HMM build commands:
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 11927849 -E 1000 --cpu 4 HMM pfamseq
Model details:
Parameter Sequence Domain
Gathering cut-off 27.0 27.0
Trusted cut-off 28.5 27.7
Noise cut-off 26.9 26.6
Model length: 122
Family (HMM) version: 3
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