PETER ARONSON

..We conclude that a DIDS-sensitive basolateral transporter is involved in mediating oxalate secretion across mouse duodenum, but Sat1 itself is dispensable for this process...

..In conclusion, absorptive oxalate flux occurs through the paracellular "leak" pathway, and net absorption of dietary oxalate depends on the relative balance between absorption and SLC26A6-dependent transcellular secretion...

..Here we apply these advances in molecular physiology to understand how acid-base disturbances affect serum potassium...

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..Thus, by virtue of its function as a Cl(-)-oxalate exchanger, CFEX plays essential roles both in proximal tubule NaCl transport and in the prevention of hyperoxaluria and calcium oxalate nephrolithiasis...

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..Finally, we cloned and functionally expressed CFEX, an anion transporter expressed on the apical surface of proximal tubule cells and capable of mediating Cl(-)-formate exchange...

..We conclude that virtually all measured Na+-H+ exchange activity in brush border membranes from control and acidotic rats is mediated by NHE3 and that metabolic acidosis causes increased expression of renal brush border NHE3 protein...

..In conclusion, we successfully generated phosphospecific antibodies that should be useful to assess the phosphorylation of endogenous NHE3 at its two PKA consensus sites under a variety of physiological conditions in vitro and in vivo...

..Expression of SLC26A7 was also detected on the brush border membrane of proximal tubule cells. Finally, we demonstrated an essential role for the scaffolding protein PDZK1 in apical membrane expression of SLC26A6...

..We conclude that although phosphorylation of NHE3 at serines 552 and 605 is regulated by PKA both in vivo and in vitro, phosphorylation of these sites does not directly alter Na(+)/H(+) exchange activity...

..We conclude that NHE8 is expressed on the apical brush-border membrane of proximal tubule cells, where it may play a role in mediating or regulating ion transport in this nephron segment...

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..We conclude that DPPIV plays an unexpected role in modulating Na+/H+ exchange mediated by NHE3 in proximal tubule cells...

..We conclude that multiple modes of anion exchange mediated by Slc26a6 are negatively regulated by PKC-delta activation...

..We conclude that Slc26a7 is expressed in the proximal tubule and thick ascending limb of the loop of Henle, and it may therefore contribute to anion transport in these nephron segments...

..In the medulla, NHE8 message was most highly expressed in the proximal tubules (S3) of the outer stripe of the outer medulla. Thus NHE8 is expressed in the proximal tubule, where it may contribute to apical membrane ion transport...

..In conclusion, the scaffolding protein PDZK1 is essential for the normal expression and function of Cl-anion exchanger CFEX in the proximal tubule of the mammalian kidney...

..In the presence of high oxalate concentrations as found in renal tubular fluid and urine, Slc26a6 may largely function as an electrogenic Cl(-)-oxalate exchanger...

..Finally, we distinguish 12 charged residues out of 22, residing within prestin's transmembrane regions, that contribute to unitary charge movement, i.e., voltage sensing. These data redefine our mechanistic concept of prestin...

..Moreover, they reveal that WNK4 regulates the activities of a diverse group of structurally unrelated ion channels, cotransporters, and exchangers...

..The life-extending effect of mutations in Indy is likely caused by an alteration in energy balance caused by a decrease in INDY transport function...

..We conclude that the anion exchanger SLC26A6 has a major constitutive role in limiting net intestinal absorption of oxalate, thereby preventing hyperoxaluria and calcium oxalate urolithiasis...

..To investigate a possible role of pendrin in modulating acid-base transport in the cortical collecting duct, we examined the regulation of expression of pendrin by acid-base status in mouse kidney...

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..These results suggest that factors that are associated with changes in distal chloride delivery govern pendrin expression in the connecting tubule and cortical collecting duct...

..Conversely, NaCl depletion induced by furosemide was associated with increased Pds expression. We conclude that Pds expression is specifically regulated in response to changes in chloride balance...

..We conclude that Slc26a6 mediates oxalate-stimulated NaCl absorption, contributes to apical membrane Cl-/base exchange in the kidney proximal tubule, and also plays an important role in HCO3- secretion in the duodenum...

..These data demonstrate that NHE8 does undergo maturational changes on the apical membrane of the rat proximal tubule and may account for the Na(+)-dependent proton flux in neonatal proximal tubules...

..These studies demonstrate that pendrin is not responsible for formate-dependent NaCl reabsorption in the proximal tubule...

..The effect of decreasing INDY activity, as in the long-lived Indy mutants, may be to alter energy metabolism in a manner that favours lifespan extension...

..NHE8 activity is Na+ dependent, displaying a cooperative sigmoidal relationship, and is highly sensitive to 5-(N-ethyl-n-isopropyl)-amiloride (EIPA). NRK cells provide a useful system where NHE8 can be studied in its native environment...

..We conclude that NHE3 exists in multiple states and that different physiological parameters control the transitions between them...

..The proposed studies are also relevant to clinical disorders of NaCI homeostasis such as hypertension and congestive heart failure. ..

..Starting in July, 1995, one stipend per year was added to the program to support the research training of individuals in urology. We request continued funding of one stipend per year for use by urologic trainees. ..

..nephrolithiasis, osteoporosis) and NaC1 transport (eg. hypertension, congestive heart failure). ..

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