scholarly journals Tenofovir Disoproxil Fumarate Is a New Substrate of ATP-Binding Cassette Subfamily C Member 11

2017 ◽  
Vol 61 (4) ◽  
Author(s):  
Wisith Tun-Yhong ◽  
Chatchai Chinpaisal ◽  
Perayot Pamonsinlapatham ◽  
Sindchai Kaewkitichai
Keyword(s):  
Tenofovir Disoproxil Fumarate ◽  
Efflux Pump ◽  
Specific Inhibitor ◽  
Atp Binding ◽  
Cellular Transport ◽  
Intracellular Accumulation ◽  
Tubular Cells ◽  
Renal Tubular Cells ◽  
Vesicular Uptake ◽  
Atp Binding Cassette

ABSTRACT Tenofovir disoproxil fumarate (TDF), a nucleotide reverse transcriptase inhibitor, after conversion to tenofovir (TFV), is mainly eliminated by glomerular filtration and active tubular secretion. The major adverse effect of tenofovir is nephrotoxicity; however, the exact mechanism remains poorly understood. In this study, the ATP-binding cassette subfamily C member 11 (ABCC11; multidrug resistance protein 8 [MRP8]) transporter, which is abundant in proximal tubular cells, was demonstrated to act as an efflux transporter of tenofovir. Real-time PCR (RT-PCR) and indirect immunofluorescence assays were used to determine MRP8 overexpression in a continuous cell line. Tenofovir accumulations were assessed by cytotoxicity, cellular transport, and vesicular uptake assays. Substrate specificity was confirmed using MK-571, an MRP-specific inhibitor, and methotrexate, which served as a known substrate. Intracellular and intravesicular concentrations of tenofovir were determined by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The 50% cytotoxic concentration (CC50) of TDF in MRP8-overexpressing cells was 4.78 times higher than that of parental cells. Transport assays also showed that the intracellular accumulation of tenofovir in MRP8-overexpressing cells was 55 times lower than that in parental cells and was partly reversed by MK-571. Similarly, an “inside-out” vesicular uptake assay, using Sf9 inverted membrane vesicles to allow measuring of accumulation of the substrates into the vesicles, demonstrated a higher intravesicular concentration of tenofovir in MRP8-overexpressing vesicles than in Sf9 insect control vesicles. These effects were effectively reversed by increasing concentrations of the specific inhibitor MK-571. In conclusion, tenofovir is a new substrate of the MRP8 transporter. An alteration in the activity of this efflux pump may increase the intracellular accumulation of tenofovir in proximal renal tubular cells.

scholarly journals Erratum for Tun-Yhong et al., “Tenofovir Disoproxil Fumarate Is a New Substrate of ATP-Binding Cassette Subfamily C Member 11”

2019 ◽  
Vol 63 (5) ◽  
Author(s):  
Wisith Tun-Yhong ◽  
Chatchai Chinpaisal ◽  
Perayot Pamonsinlapatham ◽  
Sindchai Kaewkitichai
Keyword(s):  
Tenofovir Disoproxil Fumarate ◽  
Atp Binding ◽  
Atp Binding Cassette

scholarly journals Role of ATP-Binding Cassette and Solute Carrier Transporters in Erlotinib CNS Penetration and Intracellular Accumulation

2010 ◽  
Vol 17 (1) ◽  
pp. 89-99 ◽  
Author(s):  
Mohamed A. Elmeliegy ◽  
Angel M. Carcaboso ◽  
Michael Tagen ◽  
Feng Bai ◽  
Clinton F. Stewart
Keyword(s):  
Atp Binding ◽  
Intracellular Accumulation ◽  
Solute Carrier Transporters ◽  
Solute Carrier ◽  
Cns Penetration ◽  
Atp Binding Cassette

scholarly journals Expression Analysis of ATP-Binding Cassette Transporters ABCB11 and ABCB4 in Primary Sclerosing Cholangitis and Variety of Pediatric and Adult Cholestatic and Noncholestatic Liver Diseases

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Cornelia Thoeni ◽  
Ruediger Waldherr ◽  
Jutta Scheuerer ◽  
Stefanie Schmitteckert ◽  
Ralph Roeth ◽  
...  
Keyword(s):  
Disease Progression ◽  
Primary Sclerosing Cholangitis ◽  
Liver Diseases ◽  
Sclerosing Cholangitis ◽  
Efflux Pump ◽  
Atp Binding ◽  
Cholestatic Liver Disease ◽  
Altered Expression ◽  
Outer Leaflet ◽  
Atp Binding Cassette

ATP-binding cassette (ABC) transporters are the members of the efflux pumps that are responsible for the removal of cytotoxic substances by active transport. ABCB11, the bile salt efflux pump of hepatocytes, coordinates cellular excretion of numerous conjugated bile salts into the bile canaliculi, whereas ABCB4 acts as an ATP-dependent floppase translocating phosphatidylcholine from the inner to the outer leaflet of the bile canalicular membrane. Loss of functional ABCB11 and ABCB4 proteins causes early-onset refractory cholestasis or cholangiopathy. In this study, we investigated the expression and localization pattern of ABCB11 and ABCB4 using immunohistochemistry and RNA profiling in liver samples from patients with different types and stages of chronic cholestatic liver disease, with emphasis on primary sclerosing cholangitis (PSC), compared to a variety of cholestatic and noncholestatic hepatopathies. Therefore, ABCB11 and ABCB4 expressions were investigated on formalin-fixed and paraffin-embedded (FFPE) material in a patient cohort of total 43 patients with or without cholestatic liver diseases, on protein level using immunohistochemistry and on RNA level using nanoString technology. Intriguingly, our results demonstrated increased expression of ABCB11 and ABCB4 on protein as well as RNA level in PSC, and the expression pattern correlated with disease progression. We concluded from our study that patients with PSC demonstrate altered expression levels and pattern of ABCB11 and ABCB4 which correlated with disease progression; thereby, ABCB11 and ABCB4 analysis may be a useful tool for assessment of disease stages in PSC.

scholarly journals A Putative ABC Transporter, HatABCDE, Is among Molecular Determinants of Pyomelanin Production in Pseudomonas aeruginosa

2010 ◽  
Vol 192 (22) ◽  
pp. 5962-5971 ◽  
Author(s):  
Ryan C. Hunter ◽  
Dianne K. Newman
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Abc Transporter ◽  
Atp Binding ◽  
Hypothetical Proteins ◽  
Intracellular Accumulation ◽  
Quantitative Real Time Pcr ◽  
Molecular Determinants ◽  
Tract Infections ◽  
Metabolic Transport ◽  
Atp Binding Cassette

ABSTRACT Pyomelanin overproduction is a common phenotype among Pseudomonas aeruginosa isolates recovered from cystic fibrosis and urinary tract infections. Its prevalence suggests that it contributes to the persistence of the producing microbial community, yet little is known about the mechanisms of its production. Using transposon mutagenesis, we identified factors that contribute to melanogenesis in a clinical isolate of P. aeruginosa. In addition to two enzymes already known to be involved in its biosynthesis (homogentisate dioxygenase and hydroxyphenylpyruvate dioxygenase), we identified 26 genes that encode regulatory, metabolic, transport, and hypothetical proteins that contribute to the production of homogentisic acid (HGA), the monomeric precursor of pyomelanin. One of these, PA14_57880, was independently identified four times and is predicted to encode the ATP-binding cassette of an ABC transporter homologous to proteins in Pseudomonas putida responsible for the extrusion of organic solvents from the cytosol. Quantification of HGA production by P. aeruginosa PA14 strains missing the predicted subcomponents of this transporter confirmed its role in HGA production: mutants unable to produce the ATP-binding cassette (PA14_57880) or the permease (PA14_57870) produced substantially less extracellular HGA after growth for 20 h than the parental strain. In these mutants, concurrent accumulation of intracellular HGA was observed. In addition, quantitative real-time PCR revealed that intracellular accumulation of HGA elicits upregulation of these transport genes. Based on their involvement in h omogentisic a cid t ransport, we rename the genes of this operon hatABCDE.

scholarly journals Correction for Tun-Yhong et al., “Tenofovir Disoproxil Fumarate Is a New Substrate of ATP-Binding Cassette Subfamily C Member 11”

2017 ◽  
Vol 61 (10) ◽  
Author(s):  
Wisith Tun-Yhong ◽  
Chatchai Chinpaisal ◽  
Perayot Pamonsinlapatham ◽  
Sindchai Kaewkitichai
Keyword(s):  
Tenofovir Disoproxil Fumarate ◽  
Atp Binding ◽  
Atp Binding Cassette

scholarly journals Overexpression and functional characterization of an ABC (ATP-binding cassette) transporter encoded by the genes drrA and drrB of Mycobacterium tuberculosis

2002 ◽  
Vol 367 (1) ◽  
pp. 279-285 ◽  
Author(s):  
Baisakhee Saha CHOUDHURI ◽  
Sanjib BHAKTA ◽  
Rajib BARIK ◽  
Joyoti BASU ◽  
Manikuntala KUNDU ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Abc Transporters ◽  
Efflux Pump ◽  
Functional Characterization ◽  
Atp Binding ◽  
E Coli ◽  
Neutral Compound ◽  
Genes Encoding ◽  
Simultaneous Expression ◽  
Atp Binding Cassette

The genes encoding ATP-binding cassette (ABC) transporters occupy 2.5% of the genome of Mycobacterium tuberculosis. However, none of these putative ABC transporters has been characterized so far. We describe the development of expression systems for simultaneous expression of the ATP-binding protein DrrA and the membrane integral protein DrrB which together behave as a functional doxorubicin efflux pump. Doxorubicin uptake in Escherichia coli or Mycobacterium smegmatis expressing DrrAB was inhibited by reserpine, an inhibitor of ABC transporters. The localization of DrrA to the membrane depended on the simultaneous expression of DrrB. ATP binding was positively regulated by doxorubicin and daunorubicin. At the same time, DrrB appeared to be sensitive to proteolysis when expressed alone in the absence of DrrA. Simultaneous expression of the two polypeptides was essential to obtain a functional doxorubicin efflux pump. Expression of DrrAB in E. coli conferred 8-fold increased resistance to ethidium bromide, a cationic compound. 2′,7′-bis-(2-Carboxyethyl)-5(6)-carboxyfluorescein (BCECF), a neutral compound, also behaved as a substrate of the reconstituted efflux pump. When expressed in M. smegmatis, DrrAB conferred resistance to a number of clinically relevant, structurally unrelated antibiotics. The resistant phenotype could be reversed by verapamil and reserpine, two potent inhibitors of ABC transporters.

scholarly journals A new twist in ABC transporter mediated multidrug resistance − Pdr5 is a drug/proton co-transporter

2021 ◽  
Author(s):  
Manuel Wagner ◽  
Daniel Blum ◽  
Stefanie Raschka ◽  
Christoph Gertzen ◽  
Sander Smits ◽  
...  
Keyword(s):  
Multidrug Resistance ◽  
Abc Transporters ◽  
Drug Transport ◽  
Molecular Mechanisms ◽  
Efflux Pump ◽  
Coupled Processes ◽  
Atp Binding ◽  
Cytotoxic Compounds ◽  
Hydrolysis Of ◽  
Atp Binding Cassette

The two major efflux pump systems that are involved in multidrug resistance (MDR) are (i) ATP binding cassette (ABC) transporters and (ii) secondary transporters. While the former use binding and hydrolysis of ATP to facilitate export of cytotoxic compounds, the latter utilize electrochemical gradients to expel their substrates. Pdr5 from Saccharomyces cerevisiae is a prominent member of eukaryotic ATP binding cassette (ABC) transporters that are involved in multidrug resistance (MDR) and used as a frequently studied model system. Although investigated for decades, the underlying molecular mechanisms of drug transport and substrate specificity remain elusive. Here, we provide electrophysiological data on the reconstituted Pdr5 demonstrating that this MDR efflux pump does not only actively translocate its substrates across the lipid bilayer, but at the same time generates a proton motif force in the presence of Mg2+-ATP and substrates by acting as a proton/drug co-transporter. Similar observations have not yet been reported for any other MDR efflux pump. We conclude from these results that the mechanism of MDR conferred by Pdr5 and likely other transporters is more complex than the sole extrusion of cytotoxic compounds and involves secondary coupled processes suitable to increase the effectiveness.

Sign in / Sign up

Export Citation Format

Share Document