Renal physiology of SLC26 anion exchangers.
OBJECTIVE
The multifunctional anion exchanger family (Slc26) encompasses 11 identified genes, but only 10 encode real proteins (Slc26a10 is a pseudogene). Most of the Slc26 proteins function primarily as anion exchangers, exchanging sulfate, iodide, formate, oxalate, hydroxyl ion, and bicarbonate anions, whereas other Slc26 proteins function as chloride ion channels or anion-gated molecular motors. The aim of this review is to present recent studies on the molecular function of the Slc26 family and its role in renal physiology and pathophysiology.


RESULTS
In proximal tubules, Slc26a1 (Sat-1) mediates sulfate and oxalate transport across the basolateral membrane, while Slc26a6 (CFEX, Pat-1) mediates a variety of anion exchange at the apical membrane to facilitate transcellular sodium chloride absorption. Targeted deletion of murine Slc26a6 leads to intestinal hyperabsorption of oxalate, hyperoxaluria, and kidney stones. Slc26a4 (pendrin) and Slc26a7 are expressed in intercalated cells, and are involved in acid-base homeostasis and blood pressure regulation. Messenger RNA for Slc26a2, Slc26a9, and Slc26a11 is also present in the kidney, yet the roles of these family members in renal physiology or pathophysiology are not clear.


CONCLUSIONS
Members of this multifunctional anion transporter family play evolving roles in the etiology of nephrolithiasis (Slc26a6) and hypertension (Slc26a4 and Slc26a6). Other Slc26 family members (Slc26a2, Slc26a9, Slc26a11) express mRNA in the kidney but their roles in renal physiology are not yet known.
Sindić
Aleksandra
A
Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, Minnesota 55905, and Renal Division, Brigham and Women's Hospital, Boston, Massachusetts, USA.
Chang
Min-Hwang
MH
Mount
David B
DB
Romero
Michael F
MF
D000818:Animals; D027321:Anion Transport Proteins / Q000502:physiology*; D000838:Anions; D017920:Antiporters / Q000502:physiology*; D002712:Chlorides / Q000737:chemistry; D006801:Humans; D007668:Kidney / Q000378:metabolism; D007674:Kidney Diseases / Q000378:metabolism; D007684:Kidney Tubules / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000502:physiology*; D008954:Models, Biological; D010070:Oxalates / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D000076988:Sulfate Transporters
D027321:Anion Transport Proteins; D000838:Anions; D017920:Antiporters; D002712:Chlorides; D026901:Membrane Transport Proteins; D010070:Oxalates; D012333:RNA, Messenger; C089651:SLC26A2 protein, human; C085609:SLC26A4 protein, human; C439529:SLC26A6 protein, human; C455628:SLC26A9 protein, human; D000076988:Sulfate Transporters