The principal focus of this project continues to be the mechanisms of anion transport in the proximal tubule. Studies during the past decade have supported a model by which transcellular CI-absorption in the proximal tubule involves uphill CI-uptake across the luminal membrane by exchange with formate and oxalate. Recycling of formate occurs by H/+- couple formate transport in parallel with Na/+-H/+ exchange, whereas next project period we propose to investigate two aspects of proximal tubule anion transport. First, we plan to complete the cDNA cloning and carry out the physiological characterization of a novel transporter that is likely to play a role in mediating apical membrane anion transport. Specifically, we will isolate, clone and sequence cDNAs encoding the transporter, determine anion specificity and transport modes by functional expression in Xenopus oocytes; general specific antibodies, and determine cell and membrane sites of expression; determine whether different isoforms of the transporter exist; examine structure-function relationships by use of chimeric constructs; and estimate the contribution of the transporter to integrated tubule function in microperfusion studies in mice with targeted disruption of the transporter gene. Second, in collaboration with Gerhard Giebisch (project#1), we propose to continue studies of the mechanisms of regulation of transcellular NaHCO/3 and NaCI reabsorption in the proximal tubule. Specifically, we will measure the activities of both anion exchanges (CI-formate and CI-oxalate) and recycling pathways (H+-coupled formate transport, Na/+- sulfate co-transport, oxalate-sulfate exchange) in renal brush border vesicles isolated from rats subjects to conditions that regulate proximal NaHCO/3 and NaCI reabsorption (eg. metabolic acidosis, hypokalemic alkalosis, furosemide-induced volume contraction). Activities of these pathways in membrane vesicles will be correlated with rates of transtubular HCO/3- and CI- reabsorption in the intact tubule under similar conditions. We will thereby test the hypothesis that activities of luminal membrane anion transporters are appropriate altered tot permit independent regulation of proximal tubule NaHCO/3 and NaCI reabsorption. The proposed project will provide new information on the molecular mechanisms and regulation of renal CI- transport, and is therefore of relevance for understanding clinical disorders of NaCI balance.

Project Start
2000-09-01
Project End
2000-11-30
Budget Start
1998-10-01
Budget End
1999-09-30
Support Year
27
Fiscal Year
2000
Total Cost
$148,636
Indirect Cost
Name
Yale University
Department
Type
DUNS #
082359691
City
New Haven
State
CT
Country
United States
Zip Code
06520
Kim, Jun-Mo; Xu, Shuhua; Guo, Xiaoyun et al. (2018) Urinary bladder hypertrophy characteristic of male ROMK Bartter's mice does not occur in female mice. Am J Physiol Regul Integr Comp Physiol 314:R334-R341
Gassaway, Brandon M; Petersen, Max C; Surovtseva, Yulia V et al. (2018) PKC? contributes to lipid-induced insulin resistance through cross talk with p70S6K and through previously unknown regulators of insulin signaling. Proc Natl Acad Sci U S A 115:E8996-E9005
Gilder, Allison L; Chapin, Hannah C; Padovano, Valeria et al. (2018) Newly synthesized polycystin-1 takes different trafficking pathways to the apical and ciliary membranes. Traffic 19:933-945
Barber, Karl W; Muir, Paul; Szeligowski, Richard V et al. (2018) Encoding human serine phosphopeptides in bacteria for proteome-wide identification of phosphorylation-dependent interactions. Nat Biotechnol 36:638-644
Scholl, Ute I; Stölting, Gabriel; Schewe, Julia et al. (2018) CLCN2 chloride channel mutations in familial hyperaldosteronism type II. Nat Genet 50:349-354
Barber, Karl W; Rinehart, Jesse (2018) The ABCs of PTMs. Nat Chem Biol 14:188-192
Barber, Karl W; Miller, Chad J; Jun, Jay W et al. (2018) Kinase Substrate Profiling Using a Proteome-wide Serine-Oriented Human Peptide Library. Biochemistry 57:4717-4725
Li, Jing; Hatano, Ryo; Xu, Shuhua et al. (2017) Gender difference in kidney electrolyte transport. I. Role of AT1a receptor in thiazide-sensitive Na+-Cl- cotransporter activity and expression in male and female mice. Am J Physiol Renal Physiol 313:F505-F513
Inoue, Kazunori; Balkin, Daniel M; Liu, Lijuan et al. (2017) Kidney Tubular Ablation of Ocrl/Inpp5b Phenocopies Lowe Syndrome Tubulopathy. J Am Soc Nephrol 28:1399-1407
Castañeda-Bueno, Maria; Arroyo, Juan Pablo; Zhang, Junhui et al. (2017) Phosphorylation by PKC and PKA regulate the kinase activity and downstream signaling of WNK4. Proc Natl Acad Sci U S A 114:E879-E886

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