Cystic fibrosis is caused by mutations in the gene encoding cystic transmembrane conductance regulator (CFTR). The most common mutation, DeltaF508, results production of a misfolded CFTR protein that retained endoplasmic reticulum and targeted for degradation. Curcumin nontoxic Ca-adenosine triphosphatase pump inhibitor can be administered to humans safely. Oral administration curcumin homozygous DeltaF508 mice doses comparable, on weight-per-weight basis, those well tolerated corrected...

Abstract Autosomal dominant polycystic kidney disease (ADPKD) is the most prevalent potentially lethal monogenic disorder. Mutations in PKD1 gene, which encodes polycystin-1 (PC1), account for approximately 78% of cases. PC1 a large 462-kDa protein that undergoes cleavage its N and C-terminal domains. produces fragments translocate to mitochondria. We show transgenic expression corresponding final 200 amino acid (aa) residues two Pkd1 -KO orthologous murine models ADPKD suppresses cystic...

Active K absorption in the rat distal colon is energized by an apical membrane H-K-ATPase, whereas collecting duct generally believed to be modulated a related renal H-K-ATPase. Experiments were performed establish mechanism(s) which dietary Na depletion (with resulting elevated aldosterone levels) and stimulate absorption. A colonic H-K-ATPase-specific cDNA probe polyclonal antibody utilized measure mRNA (Northern blot analyses) protein (Western immunofluorescence studies) abundance...

Polycystin (PC)1 and PC2 are membrane proteins implicated in autosomal dominant polycystic kidney disease. A physiologically relevant cleavage at PC1's G protein-coupled receptor proteolytic site (GPS) occurs early the secretory pathway. Our results suggest that increases both PC1 GPS appearance plasma membrane. Mutations prevent its localization. is a member of trp family cation channels an important binding partner. The effect on localization independent channel activity, as tested using...

Gastric acid secretion is mediated by the H/K-ATPase of parietal cells. Activation involves insertion into cell plasmalemma, while its cessation associated with reinternalization an intracellular storage compartment. The cytoplasmic tail β subunit includes a four residue sequence homologous to tyrosine-based endocytosis signals. We generated transgenic mice expressing H/K- ATPase in which this motif's tyrosine mutated alanine. glands from animals mutant constitutively secrete and...

Mutations in PKD1 and PKD2, the genes that encode polycystin-1 polycystin-2 respectively, account for almost all cases of autosomal dominant polycystic kidney disease. Although polycystins are believed to interact vivo, two proteins often display dissimilar patterns gradients expression during development. In an effort understand this apparent discrepancy, we investigated how changes can affect subcellular localization polycystin-1. We show that, when is expressed alone a PKD2 null cell...

This study sought to establish the presence of K(+)-activated adenosinetriphosphatase (ATPase) activity in colonic mucosa rat distal colon. ATPase was present apical membranes but not basolateral membranes. represented an approximate 10-fold enrichment compared with that homogenate. Na(+)-K(+)-activated also homogenate enriched less than fourfold had both ouabain-sensitive and ouabain-insensitive components. In contrast, completely inhibited by ouabain. Similar half-maximal concentrations...

A putative cDNA for the colonic K-ATPase has recently been cloned (Crowson, M.S., and G. E. Shull. 1992. J. Biol. Chem. 267:13740-13748). Considerable evidence exists that there are two K-ATPases active K absorptive processes in rat distal colon: one is ouabain sensitive other insensitive. The present study used baculovirus expression system to express activity insect Spodoptera frugiperda (Sf 9) cells a polyclonal antibody (M-1), developed against fusion protein produced from 327 nucleotide...

This study establishes the characteristics of electroneutral Na-H exchange present in apical membrane vesicles isolated from colonocytes rat large intestine. An outward directed proton gradient stimulated 22Na uptake and demonstrated transient accumulation that was not altered by voltage clamping with K its ionophore, valinomycin. Amiloride inhibited gradient-stimulated (0.1 mM) 97% a noncompetitive mechanism Ki 27 microM. 5-(N-ethyl-N-isopropyl)amiloride, an amiloride analogue which is...

This study sought to characterize the mechanism of Na transport across basolateral membrane vesicles rat distal colon. Both an outward proton gradient and inward bicarbonate stimulated 22Na uptake. Proton gradient-stimulated uptake was activated severalfold by additional presence gradient, significantly enhanced imposed intravesicular positive potential. 0.1 mM amiloride inhibited both gradient- 80 95%, respectively, while 1 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS) 40 80%,...

The calcium-sensing receptor (CaSR) belongs to the G-protein-coupled superfamily and plays critical roles in divalent ion homeostasis cell differentiation. Since extracellular Ca2+ is essential for development of stable epithelial tight junctions (TJ), we hypothesized that CaSR may participate regulating TJ assembly. We first assessed expression Madin-Darby Canine Kidney (MDCK) cells at steady-state following manipulations modulate Next, examined effects agonists antagonists on...

Abstract Na-H exchange is present in apical membrane vesicles (AMV) isolated from distal colon of normal rats. Because intact tissue aldosterone both induces amiloride-sensitive electrogenic sodium transport and inhibits electroneutral absorption, these studies with AMV were designed to establish the effect on transport. An outward-directed proton gradient stimulated 22Na uptake dietary depleted (with elevated levels) experimental Unlike AMV, gradient-dependent was inhibited when measured...

Renal regulation of mammalian water homeostasis is mediated by the aquaporin-1 (AQP1) channel, which expressed in apical and basolateral membranes proximal tubules descending limbs Henle, aquaporin-2 (AQP2), redistributed from intracellular vesicles to membrane (AM) collecting duct cells with vasopressin. In transfected Madin-Darby canine kidney cells, AQP1 AQP2 are regulated similarly, indicates that routing elements reside their primary sequences. We studied role COOH terminus shuttling....

This study utilized intestinal brush-border membrane vesicles obtained from organ donor intestine to characterize the absorption of D-glucose and L-leucine in human intestine. Both were taken up by sodium gradient-dependent active transport along entire length small The relative magnitude for both substrates under gradient conditions followed order distal jejunum greater than proximal ileum. number carrier systems these was estimated Eadie-Hofstee plot analysis. analysis revealed that...

Polycystin-1 (PC-1) is the product of PKD1 gene, which mutated in autosomal dominant polycystic kidney disease. We show that Na,K-ATPase alpha-subunit interacts vitro and vivo with final 200 amino acids polycystin-1 protein, constitute its cytoplasmic C-terminal tail. Functional studies suggest this association may play a role regulation activity. Chinese hamster ovary cells stably expressing entire PC-1 protein exhibit dramatic increase activity, although kinetic properties enzyme remain...

In the chronically inflamed ileum, unique mechanisms of alteration similar transport processes suggest regulation by different immune-inflammatory mediator pathways. a rabbit model chronic ileitis, we previously demonstrated that Na + -glucose cotransport was inhibited decrease in cotransporter numbers, whereas -amino acid affinity for amino acid. this study, -bile reduced villus cells from ileum. cell brush-border membrane vesicles as well, suggesting direct effect at itself. Kinetic...

This study describes Cl-HCO3 and Cl-OH exchanges as the mechanism for Cl uptake by apical membrane vesicles (AMV) of rat distal colon. Although HCO3 gradient-stimulated 36Cl was additionally stimulated additional presence a pH gradient, not further enhanced gradient. OH inhibited voltage clamping, with K its ionophore valinomycin, but 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid, an anion exchange inhibitor, apparent inhibitory constant 7.8 106.0 microM, respectively. Increasing...

This study characterizes the transport of radiolabeled acidic amino acids into brush-border membrane vesicles prepared from human jejunum. The uptakes L-glutamic, L-aspartic, and D-aspartic were stimulated by a Na+ gradient (extravesicular greater than intravesicular). Concentrative uptake (resulting in an "overshoot" phenomenon) these dicarboxylic occurred when there was outward K+ (intravesicular extravesicular). In addition, increasing gradients (0-100 mM) resulted enhanced L-glutamic...

A bstract : The sorting and regulation of the Na,K H,K‐ATPases requires that pump proteins must associate, at least transiently, with kinases, phosphatases, scaffolding molecules, components cellular trafficking machinery. identities these interacting nature their associations polypeptides have yet to be elucidated. We begun a series yeast two‐hybrid screens employing structurally defined segments as baits in order gain insight into function proteins.

A proton-peptide symport mechanism has been postulated for transport of dipeptides in rabbit intestinal and renal brush-border membrane vesicles (BBMV). We have investigated the effects a transmembrane potential (in mouse) an inwardly directed proton gradient mouse, rabbit, human) on glycyl-L-proline BBMV. Membrane alterations, induced by permeant anions or generated K+-diffusion presence valinomycin, did not accelerate uptake glycyl-L-proline. In contrast, parallel experiments D-glucose,...

Mutations in the genes encoding polycystin-1 (PC1) and polycystin 2 (PC2) cause autosomal dominant polycystic kidney disease. These transmembrane proteins colocalize primary cilia of renal epithelial cells, where they may participate sensory processes. PC1 is also found apical membrane when expressed cultured cells. undergoes autocatalytic cleavage, producing an extracellular N-terminal fragment that remains noncovalently attached to C-terminus. Exposing cells alkaline solutions elutes while...