Georg Lamprecht

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NHE3 is the apically located Na+/H+ exchanger in the gut and in the renal proximal tubule. Acute inhibition of this transporter by cAMP requires the presence of either of two NHE3-associated proteins, NHERF or E3KARP. It has been suggested that these proteins either directly regulate NHE3 activity after being phosphorylated by protein kinase A (PKA) or that(More)
Cyclic AMP is a major second messenger that inhibits the brush border Na+/H+ exchanger NHE3. We have previously shown that either of two related regulatory proteins, E3KARP or NHERF, is necessary for the cAMP-dependent inhibition of NHE3. In the present study, we characterized the interaction between NHE3 and E3KARP using in vitro binding assays. We found(More)
In the gastrointestinal tract, CFTR, in conjunction with one or several members of the SLC26 anion exchanger family, mediates electrogenic Cl- and HCO3- secretion. Na+/H+ exchanger isoform NHE3, on the other hand, coupled to one or several of the SLC26 isoforms, mediates electroneutral NaCl absorption. The agonist-induced activation of anion secretion and(More)
BACKGROUND & AIMS Duodenal bicarbonate secretion is in part mediated by an apical Cl-/HCO3- exchanger of unknown molecular nature. The recently discovered dra (down-regulated in adenoma) gene encodes a transport protein (DRA) for SO4(2-), Cl-, and HCO3-. The aim of this study was to investigate whether DRA may be the duodenal apical Cl-/HCO3- exchanger. (More)
The solute carrier gene family SLC26 consists of tissue-specific anion exchanger genes, three of them associated with distinct human recessive disorders. By a genome-driven approach, several new SLC26 family members have been identified, including a kidney- and pancreas-specific gene, SLC26A6. We report the functional characterization of SLC26A6 and two new(More)
The members of the regulatory factor (RF) gene family, Na(+)/H(+) exchanger (NHE)-RF and NHE3 kinase A regulatory factor (E3KARP) are necessary for cAMP to inhibit the epithelial brush border NHE isoform 3 (NHE3). The mechanism of their action was studied using PS120 fibroblasts stably transfected with rabbit NHE3 and wild type rabbit NHE-RF or wild type(More)
Intestinal electroneutral NaCl absorption is mediated by parallel operation of Na(+)/H(+) and Cl(-)/HCO(3)(-) exchange in the enterocyte apical membrane. The ion transporters involved are Na(+)/H(+) exchanger 3 (NHE3) and the down regulated in adenoma (dra) gene product. cAMP-mediated inhibition of NHE3 requires the transporter to bind to the second PDZ(More)
DRA (down regulated in adenoma) is an intestinal anion exchanger, acting in parallel with NHE3 to facilitate ileal and colonic NaCl absorption. Furthermore it is involved in small intestinal bicarbonate secretion. Because DRA has a PDZ interaction motif, which may influence its properties, we searched for DRA-interacting PDZ adapter proteins in the small(More)
Electroneutral NaCl absorption in the intestine is mediated by parallel Na+/H+ and Cl−/HCO3− exchange. Mutations in the down-regulated in adenoma (DRA) gene cause congenital chloride diarrhoea but the transport characteristics of human DRA have not been studied in a heterologous human expression system. A N-terminal enhanced green fluorescence protein(More)
A hundred and ninety-six textile samples were tested in a modified version of the Salmonella/microsome assay for release of mutagenic contaminants. As heat sterilization of the samples can result in reduction of mutagenic activity, tests were performed with streptomycin resistant derivatives of Salmonella tester strains TA98 and TA100. Textile samples were(More)