Evidence for two nonidentical drug-interaction sites in the human P-glycoprotein.
AuthorsDey S, Ramachandra M, Pastan I, Gottesman MM, Ambudkar SV
JournalProc Natl Acad Sci U S A
PubMed ID9380680
'Human P-glycoprotein (Pgp) confers multidrug resistance to cancer cells by ATP-dependent extrusion of a great many structurally dissimilar hydrophobic compounds. The manner in which Pgp recognizes these different substrates is unknown. The protein shows internal homology between its N- and C-terminal halves, each comprised of six putative transmembrane helices and ... More
Multidrug transporter activity in lymphocytes.
AuthorsElliott JI, Raguz S, Higgins CF,
JournalBr J Pharmacol
PubMed ID15492020
'Multidrug transporters play a dual role in haematopoietic cells, mediating the efflux of xenobiotics and regulating cell migration. For several reasons including the lack of specific antibodies, reports of multidrug transporter distribution on lymphocytes conflict. Murine B cells have been reported to completely lack transporter activity. Through analysis of parental ... More
Release of amines from acidified stores following accumulation by Transport-P.
AuthorsAl-Damluji S, Shen WB
JournalBr J Pharmacol
PubMed ID11181426
'1. Transport-P is an uptake process for amines in peptidergic neurones of the hypothalamus. It differs from other uptake processes by its anatomical location in post-synaptic neurones, its functional properties and by the structure of its ligands. Transport-P accumulates amines in intracellular vesicles, derives its energy from the electrochemical proton ... More
Visual detection of transport-P in peptidergic neurones.
Authorsal-Damluji S, Porter D, Krsmanovic LZ, Knutson JR, Kopin IJ
JournalBr J Pharmacol
PubMed ID9138694
'1. Hypothalamic peptidergic neurones possess an uptake process for amines (transport-P), for which prazosin is a substrate. It is characterized by a paradoxical increase in the accumulation of [3H]-prazosin when the concentration of unlabelled prazosin is increased above 10(-7) M. This increase is due to activation of a proton-dependent, vacuolar-type ... More
Pharmacological implications of cellular localization of alpha1-adrenoceptors in native smooth muscle cells.
AuthorsMcGrath JC, Mackenzie JF, Daly CJ
JournalJ Auton Pharmacol
PubMed ID10961735
'1. This study examines the cellular localization of alpha1-adrenoceptors and demonstrates that binding to intracellular receptive binding sites in native smooth muscle cells may influence the pharmacological profile of agonists or antagonists. The example tissue studied was rat basilar artery. 2. An alpha1-adrenoceptor antagonist and fluorescent analogue of prazosin, BODIPY-FL ... More
Flow cytometry analysis of alpha1-adrenoceptor subtypes.
AuthorsHirasawa A, Tsumaya K, Awaji T, Shibata K, Homma N, Shinomiya T, Tsujimoto G
JournalFEBS Lett
PubMed ID8647269
To characterize the alpha1-adrenoceptor subtypes, we developed a flow cytometry method using the fluorescent ligand BODIPY-FL prazosin and the anti-peptide antibody against the alpha1b-adrenoceptor amino terminus (designated 1B-N1-C) as probes. Three alpha1-adrenoceptors (alpha1a, alpha1b and alpha1d) expressed in CHO cells were detected by BODIPY-FL prazosin; however, only alpha1b-adrenoceptor subtype was ... More
Alpha1A/B-knockout mice explain the native alpha1D-adrenoceptor's role in vasoconstriction and show that its location is independent of the other alpha1-subtypes.
AuthorsMethven L, Simpson PC, McGrath JC,
JournalBr J Pharmacol
PubMed ID19888965
BACKGROUND AND PURPOSE: Theoretically, three alpha(1)-adrenoceptor subtypes can interact at the signalling level to alter vascular contraction or at the molecular level to alter each other's cellular location. The alpha(1A/B)-adrenoceptor knockout mouse (alpha(1A/B)-KO) was used to study the isolated alpha(1D)-adrenoceptor to consider these potential interactions in native tissue. EXPERIMENTAL APPROACH: ... More
The alpha(1B/D)-adrenoceptor knockout mouse permits isolation of the vascular alpha(1A)-adrenoceptor and elucidates its relationship to the other subtypes.
AuthorsMethven L, McBride M, Wallace GA, McGrath JC,
JournalBr J Pharmacol
PubMed ID19572943
BACKGROUND AND PURPOSE: Mesenteric and carotid arteries from the alpha(1B/D)-adrenoceptor knockout (alpha(1B/D)-KO) were employed to isolate alpha(1A)-adrenoceptor pharmacology and location and to reveal these features in the wild-type (WT) mouse. EXPERIMENTAL APPROACH: Functional pharmacology by wire myography and receptor localization by confocal microscopy, using the fluorescent alpha(1)-adrenoceptor ligand BODIPY FL-Prazosin ... More
Transplacental pharmacokinetics of glyburide, rhodamine 123, and BODIPY FL prazosin: effect of drug efflux transporters and lipid solubility.
AuthorsCygalova LH, Hofman J, Ceckova M, Staud F,
JournalJ Pharmacol Exp Ther
PubMed ID19779128
Breast cancer resistance protein (BCRP) and P-glycoprotein (P-gp) are the most abundantly expressed ATP-binding cassette (ABC) drug transporters in the placenta. They recognize a large, partly overlapping spectrum of chemically unrelated compounds and affect their transplacental passage. In this study we investigate the effect of Bcrp and P-gp on the ... More
BacMam recombinant baculovirus in transporter expression: a study of BCRP and OATP1B1.
AuthorsHassan NJ, Pountney DJ, Ellis C, Mossakowska DE
JournalProtein Expr Purif
PubMed ID16481201
Human BCRP and OATP1B1 have recently been identified as important transporters in the absorption, distribution, and elimination of clinically significant drugs. In this report, we illustrate the use of modified baculoviruses, termed BacMam viruses for the expression of functional BCRP and OATP1B1 in mammalian cells. We show a variety of ... More
Interaction of the breast cancer resistance protein with plant polyphenols.
AuthorsCooray HC, Janvilisri T, van Veen HW, Hladky SB, Barrand MA
JournalBiochem Biophys Res Commun
PubMed ID15047179
Multidrug transporters influence drug distribution in vivo and are often associated with tumour drug resistance. Here we show that plant-derived polyphenols that interact with P-glycoprotein can also modulate the activity of the recently discovered ABC transporter, breast cancer resistance protein (BCRP/ABCG2). In two separate BCRP-overexpressing cell lines, accumulation of the ... More
[Flow cytometry and laser scanning confocal microscopy analysis of the receptor distribution]
AuthorsHirasawa A, Awaji T, Tsujimoto G
JournalNippon Yakurigaku Zasshi
PubMed ID8537072
To study the physiological regulation of the receptor protein, a fluorescent probe and detection system for alpha 1B-adrenergic receptors have been developed. By using the anti-peptide antibody developed against the alpha 1B-adrenergic receptor NH2-terminus, we have examined the agonist-regulated alpha 1B-adrenergic receptor redistribution in desensitized cells. Flow cytometry analysis showed ... More
Differences in the subcellular localization of alpha1-adrenoceptor subtypes can affect the subtype selectivity of drugs in a study with the fluorescent ligand BODIPY FL-prazosin.
AuthorsSugawara T, Hirasawa A, Hashimoto K, Tsujimoto G
JournalLife Sci
PubMed ID12002804
G protein-coupled receptor (GPCR) subtypes are differentially distributed in the cell; however, it remains unclear how this affects the subtype selectivity of particular drugs. In the present study, we used flow cytometry analysis with the fluorescent ligand, BODIPY FL-prazosin, to study the relationship between the subcellular distribution of subtype receptors ... More
Fluorescent ligands, antibodies, and proteins for the study of receptors.
AuthorsDaly CJ, McGrath JC
JournalPharmacol Ther
PubMed ID14609715
Fluorescent molecules bound to receptors can show their location and, if binding is reversible, can provide pharmacological information such as affinity and proximity between interacting molecules. The spatial precision offered by visualisation transcends the diverse localisation and low molecular concentration of receptor molecules. Consequently, the relationships between receptor location and ... More
A functional assay for detection of the mitoxantrone resistance protein, MXR (ABCG2).
AuthorsRobey RW, Honjo Y, van de Laar A, Miyake K, Regis JT, Litman T, Bates SE
JournalBiochim Biophys Acta
PubMed ID11406094
The fluorescent compounds rhodamine 123, LysoTracker Green DMD-26, mitoxantrone, and BODIPY-prazosin were used with the antagonist fumitremorgin C (FTC) in order to develop functional assays for the half-transporter, MXR/BCRP/ABCP1. A measure of FTC-inhibitable efflux was generated for each compound in a series of MXR-overexpressing drug-selected cell lines and in ten ... More
Mutations at amino-acid 482 in the ABCG2 gene affect substrate and antagonist specificity.
AuthorsRobey RW, Honjo Y, Morisaki K, Nadjem TA, Runge S, Risbood M, Poruchynsky MS, Bates SE
JournalBr J Cancer
PubMed ID14612912
Recent studies have shown that mutations at amino-acid 482 in the ABCG2 gene affect the substrate specificity of the protein. To delineate the effects of these mutations clearly, human embryonic kidney cells (HEK-293) were stably transfected with wild-type 482R or mutant 482G and 482T ABCG2. By flow cytometry, mitoxantrone, BODIPY-prazosin, ... More
Quantitative imaging in live human cells reveals intracellular alpha(1)-adrenoceptor ligand-binding sites.
Cellular distribution and binding characteristics of native alpha(1)-adrenoceptors (ARs) were determined in a live, single, human smooth muscle cell (SMC) with confocal laser scanning microscopy and a fluorescent ligand, BODIPY-FL prazosin (QAPB). This allowed single-cell competitive ligand binding and showed that 40% of alpha(1)-AR-binding sites in native cells are intracellular. ... More
Functional characterization of coding polymorphisms in the human MDR1 gene using a vaccinia virus expression system.
AuthorsKimchi-Sarfaty C, Gribar JJ, Gottesman MM
JournalMol Pharmacol
PubMed ID12065748
The human MDR1-encoded transporter is a 170-kDa plasma membrane glycoprotein [P-glycoprotein (P-gp)] capable of binding and energy-dependent extrusion of structurally diverse organic compounds and drugs. P-gp seems to play a significant role in uptake, distribution, and excretion of many different drugs. To determine whether common polymorphic forms of P-gp are ... More
Function of the ABC transporters, P-glycoprotein, multidrug resistance protein and breast cancer resistance protein, in minimal residual disease in acute myeloid leukemia.
Authorsvan der Pol MA, Broxterman HJ, Pater JM, Feller N, van der Maas M, Weijers GW, Scheffer GL, Allen JD, Scheper RJ, van Loevezijn A, Ossenkoppele GJ, Schuurhuis GJ
JournalHaematologica
PubMed ID12604403
BACKGROUND AND OBJECTIVES: Relapse is common in acute myeloid leukemia (AML) because of persistence of minimal residual disease (MRD). ABC-transporters P-glycoprotein (Pgp) and multidrug resistance protein (MRP), are thought to contribute to treatment failure, while it is unknown whether breast cancer resistance protein (BCRP) does so. However, whether up-regulation of ... More
Developmental expression and regulation of alpha 1 adrenergic receptors in cultured cortical neurons.
AuthorsWang Y, Gu Q, Mao F, Cynader MS
JournalBrain Res Dev Brain Res
PubMed ID9298232
The expression and distribution of alpha 1 receptors in cultured neurons derived from rat visual cortex were studied with confocal microscopy using the fluorescently labeled alpha 1 adrenergic receptor selective antagonist BODIPY FL prazosin. The receptors were found to be clustered on neuronal somata and on proximal dendrites. We found ... More
Murine breast cancer feed arteries are thin-walled with reduced α1A-adrenoceptor expression and attenuated sympathetic vasocontraction.
Authors
JournalBreast Cancer Res
PubMed ID29566737
Modeling Psychomotor Retardation using iPSCs from MCT8-Deficient Patients Indicates a Prominent Role for the Blood-Brain Barrier.
Authors
JournalCell Stem Cell
PubMed ID28526555
Small Molecule Enhancers of Endosome-to-Cytosol Import Augment Anti-tumor Immunity.