Bicarbonate transporter-like, transmembrane domain
IPR011531
Definition
Bicarbonate (HCO3-) transport mechanisms are the principal regulators of pH in animal cells. Such transport also plays a vital role in acid-base movements in the stomach, pancreas, intestine, kidney, reproductive organs and the central nervous system. Functional studies have suggested four different HCO3-transport modes. Anion exchanger proteins exchange HCO3-for Cl-in a reversible, electroneutral manner PMID:2289848. Na+/HCO3-co-transport proteins mediate the coupled movement of Na+and HCO3-across plasma membranes, often in an electrogenic manner PMID:9261985. Na+driven Cl-/HCO3-exchange and K+/HCO3-exchange activities have also been detected in certain cell types, although the molecular identities of the proteins responsible remain to be determined. Sequence analysis of the two families of HCO3-transporters that have been cloned to date (the anion exchangers and Na+/HCO3-co-transporters) reveals that they are homologous. This is not entirely unexpected, given that they both transport HCO3-and are inhibited by a class of pharmacological agents called disulphonic stilbenes PMID:9235899. They share around ~25-30% sequence identity, which is distributed along their entire sequence length, and have similar predicted membrane topologies, suggesting they have ~10 transmembrane (TM) domains. This entry represents transmembrane segments of bicarbonate transporters and related proteins. In animals, this domain is found at the C terminus of many bicarbonate and similar multifunctional transporters. The crystal structure of Band 3 anion transport protein, the founding member of the solute carrier 4 (SLC4) family of bicarbonate transporters, has been solved. This protein functions both as a transporter that mediates electroneutral anion exchange across the cell membrane and as a structural protein [[cite:PMID:24121512], [cite:PMID:29438259], [cite:PMID:26542571], [cite:PMID:29500354]]. Boron transporters from plants and yeast comprise only transmembrane segments, confirmed by the solved structures [[cite:PMID:12447444], [cite:PMID:27601653], [cite:PMID:27717063]]. In plants, boron is essential for maintaining the integrity of cell walls; this transporter mediates boron translocation from roots to shoots under boron limitation PMID:27449211. Boron transporter 1 from Saccharomyces cerevisiae protects yeast cells from boron toxicity and is involved in the trafficking of proteins to the vacuole. The mechanism of its activity seems to be consistent with this described for other members of the family [[cite:PMID:27717063], [cite:PMID:17459946]].
10 human proteins with this domain
Each is a reviewed human protein in the Seroatlas serome and a potential autoantibody target; this domain groups them into one antibody-relevant category. Every entry links to its own record.
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