Disease relevance of SLC26A7

• Additional studies are needed to ascertain the role of SLC26A7 in enhanced bicarbonate absorption in outer medullary collecting duct in hypokalemia and in acid-base regulation in conditions that are associated with increased medullary tonicity [1].

High impact information on SLC26A7

• Expression of SLC26A7 in oocytes or HEK293 cells generated a Cl(-) current with linear I/V and an instantaneous current that was voltage- and time-independent [2].
• Measurement of membrane potential and pH(i) showed minimal OH(-) and HCO(3)(-) transport by SLC26A7 when the cells were incubated in Cl(-)-containing or Cl(-)-free media [2].
• Incubating the cells with HCO(3)(-) or butyrate acidified the cytosol and increased the selectivity of SLC26A7 for Cl(-) [2].
• The activity of SLC26A7 was inhibited by all inhibitors of anion transporters tested, 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid, diphenylamine-2-carboxylic acid, and glybenclamide [2].
• More detailed characterization by immunohistochemistry and/or in situ hybridization localized SLC26A7 to distal segments of nephrons, SLC26A8 to developing spermatocytes, and SLC26A9 to the lumenal side of the bronchiolar and alveolar epithelium of lung [3].

Biological context of SLC26A7

• Alternative splicing and polyadenylation of SLC26A7 pre-mRNA in kidney suggest the existence of two protein isoforms, SLC26A7.1 and SLC26A7.2, differing in their carboxy termini [4].
• The trafficking to the cell surface suggests novel functional upregulation of SLC26A7 in states that are associated with hypokalemia or increased medullary tonicity [1].
• The induction of SLC26A7 by vasopressin in OMCD cells of Brattleboro rats is likely an attempt by cells to regulate their cell volume and maintain HCO(3)(-) absorption in a state associated with increased interstitial medullary tonicity [5].
• Tissue distribution studies by RT-PCR and Northern hybridizations demonstrated the exclusive expression of this transporter, also known as SLC26A7, to stomach and kidney, with the stomach expression significantly more abundant [6].

Anatomical context of SLC26A7

• Expression of SLC26A7-A9 proteins in Xenopus oocytes demonstrated chloride, sulfate, and oxalate transport activity, suggesting that they encode functional anion exchangers [3].
• The SLC26A7-A9 proteins are structurally very similar at the amino acid level to the previous family members and show tissue-specific expression in kidney, testis, and lung, respectively [3].
• Molecular cloning of SLC26A7, a novel member of the SLC26 sulfate/anion transporter family, from high endothelial venules and kidney [4].
• SLC26A7 is expressed in extraglomerular mesangial cells and a subpopulation of intercalated cells of collecting ducts [7].
• Expression of SLC26A7 was also detected on the brush border membrane of proximal tubule cells [8].

Associations of SLC26A7 with chemical compounds

• Here, we report the molecular cloning from human HEVEC of a 2.9-kb cDNA encoding SLC26A7, a novel member of the SLC26 (solute carrier 26) sulfate/anion exchanger family [4].
• Chloride/bicarbonate exchanger SLC26A7 is localized in endosomes in medullary collecting duct cells and is targeted to the basolateral membrane in hypertonicity and potassium depletion [1].
• In conclusion, vasopressin increases the expression of SLC26A7 protein through posttranscriptional mechanisms in the OMCD [5].

Regulatory relationships of SLC26A7

• The presence of mitogen-activated protein kinase inhibitors blocked the trafficking of SLC26A7 to the plasma membrane [1].
• The increased SLC26A7 expression directly correlated with enhanced aquaporin-2 expression, which is proportional to increased interstitial osmolarity in the medulla [5].

Other interactions of SLC26A7

• SLC26A6 and SLC26A7 anion exchangers have a distinct distribution in human kidney [7].
• A chimera that was composed of the amino terminal fragment of SLC26A7 and the carboxyl terminal fragment of SLC26A1, and a C-terminal-truncated SLC26A7 were retained in the cytoplasm in hypertonicity [1].
• Double-labeling studies demonstrated the localization of SLC26A7 to the transferrin receptor-positive endosomes [1].

Analytical, diagnostic and therapeutic context of SLC26A7

• Northern blot analysis revealed specific expression of SLC26A7 mRNA in kidney [4].
• The expression of SLC26A7 protein, as examined by immunofluorescence, was undetectable in kidneys of Brattleboro rats [5].
• The purpose of the present experiments was to examine the expression of SLC26A7 in kidneys of vasopressin-deficient Brattleboro rats before and after treatment with desamino-Cys(1),d-Arg(8)-vasopressin (dDAVP) [5].
• Cellular distribution studies by RT-PCR and Northern hybridizations demonstrated predominant localization of SLC26A7 in gastric parietal cells [6].

References