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1994

Biomedical and Pharmaceutical Sciences Faculty Publications

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Full-Text Articles in Medicine and Health Sciences

Functional Comparisons Of Three Glutamate Transporter Subtypes Cloned From Human Motor Cortex, Jeffrey L. Arriza, Wendy A. Fairman, Jacques I. Wadiche, Geoffrey H. Murdoch, Michael Kavanaugh, Susan G. Amara Jan 1994

Functional Comparisons Of Three Glutamate Transporter Subtypes Cloned From Human Motor Cortex, Jeffrey L. Arriza, Wendy A. Fairman, Jacques I. Wadiche, Geoffrey H. Murdoch, Michael Kavanaugh, Susan G. Amara

Biomedical and Pharmaceutical Sciences Faculty Publications

Reuptake plays an important role in regulating synaptic and extracellular concentrations of glutamate. Three glutamate transporters expressed in human motor cortex, termed EAAT1, EAAT2, and EAAT3 (for excitatory amino acid transporter), have been characterized by their molecular cloning and functional expression. Each EAAT subtype mRNA was found in all human brain regions analyzed. The most prominent regional variation in message content was in cerebellum where EAAT1 expression predominated. EAAT1 and EAAT3 mRNAs were also expressed in various non- nervous tissues, whereas expression of EAAT2 was largely restricted to brain. The kinetic parameters and pharmacological characteristics of transport mediated by each …


Cell-Surface Receptors For Gibbon Ape Leukemia Virus And Amphotropic Murine Retrovirus Are Inducible Sodium-Dependent Phosphate Symporters, Michael Kavanaugh, Daniel G. Miller, Weibin Zhang, Wendy Law, Susan L. Kozak, David Kabat, A. Dusty Miller Jan 1994

Cell-Surface Receptors For Gibbon Ape Leukemia Virus And Amphotropic Murine Retrovirus Are Inducible Sodium-Dependent Phosphate Symporters, Michael Kavanaugh, Daniel G. Miller, Weibin Zhang, Wendy Law, Susan L. Kozak, David Kabat, A. Dusty Miller

Biomedical and Pharmaceutical Sciences Faculty Publications

Cell surface receptors for gibbon ape leukemia virus (Glvr-1) and murine amphotropic retrovirus (Ram-1) are distinct but related proteins having multiple membrane-spanning regions. Distant homology with a putative phosphate permease of Neurospora crassa suggested that these receptors might serve transport functions. By expression in Xenopus laevis oocytes and in mammalian cells, we have identified Glvr-1 and Ram-1 as sodium-dependent phosphate symporters. Two-electrode voltage-clamp analysis indicates net cation influx, suggesting that phosphate is transported with excess sodium ions. Phosphate uptake was reduced by > 50% in mouse fibroblasts expressing amphotropic envelope glycoprotein, which binds to Ram-1, indicating that Ram-1 is a major …


Control Of Cationic Amino Acid Transport And Retroviral Receptor Functions In A Membrane Protein Family, Michael Kavanaugh, Hao Wang, Zheng Zhang, Weibin Zhang, Yan-Na Wu, Esther Dechant, R. Alan North, David Kabat Jan 1994

Control Of Cationic Amino Acid Transport And Retroviral Receptor Functions In A Membrane Protein Family, Michael Kavanaugh, Hao Wang, Zheng Zhang, Weibin Zhang, Yan-Na Wu, Esther Dechant, R. Alan North, David Kabat

Biomedical and Pharmaceutical Sciences Faculty Publications

A partial cDNA sequence indicated that the T lymphocyte early-activation gene (Tea) encodes a protein related to the dual-function ecotropic retrovirus receptor/cationic amino acid transporter (ecoR/CAT1), and RNA blots suggested highest Tea expression in T lymphocytes and liver (MacLeod, C.L., Finley, K., Kakuda, D. Kozad, C.A., and Wilkinson, M.F. (1990) Mol. Cell. Biol. 7, 3663-3674). The sequence of full-length Tea cDNA from liver (3683 bases) predicts a 657-amino-acid protein (CAT2 alpha) with 12-14 transmembrane domains. A long (515 base) region with six initiation codons and termination codons precedes the translation start codon. The liver Tea cDNA is identical to Tea …


Functional Expression Of Two Glucose Transporter Isoforms From The Parasitic Protozoan Leishmania Enriettii, Chris K. Langford, Brian M. Little, Michael Kavanaugh, Scott M. Landfear Jan 1994

Functional Expression Of Two Glucose Transporter Isoforms From The Parasitic Protozoan Leishmania Enriettii, Chris K. Langford, Brian M. Little, Michael Kavanaugh, Scott M. Landfear

Biomedical and Pharmaceutical Sciences Faculty Publications

The parasitic protozoan Leishmania enriettii contains a family of tandemly repeated genes, designated Pro-1, that encode proteins with significant sequence similarity to mammalian facilitative glucose transporters. Pro-1 mRNAs are expressed almost exclusively in the promastigote or insect stage of the parasite life cycle. The Pro-1 tandem repeat encodes two isoforms of the putative transporter, iso-1 and iso-2, which have identical predicted amino acid sequences except for their NH2-terminal hydrophilic domains. We have now expressed both iso-1 and iso-2 by microinjecting their RNAs into Xenopus oocytes and assaying these oocytes for transport of various radiolabeled ligands. Both iso-1 and iso-2 transport …


Cloning Of The Cellular Receptor For Amphotropic Murine Retroviruses Reveals Homology To That For Gibbon Ape Leukemia Virus, Daniel G. Miller, Robert H. Edwards, A. Dusty Miller Jan 1994

Cloning Of The Cellular Receptor For Amphotropic Murine Retroviruses Reveals Homology To That For Gibbon Ape Leukemia Virus, Daniel G. Miller, Robert H. Edwards, A. Dusty Miller

Biomedical and Pharmaceutical Sciences Faculty Publications

The host and tissue specificity of retrovirus infection is largely determined by specific cellular receptors that mediate virus entry. Genes encoding these receptors are widely distributed in the genome, and the receptors identified to date show no sequence similarity. We have identified the cellular receptor for amphotropic murine retroviruses, Ram-1, by screening a rat cDNA expression library introduced into amphotropic virus-resistant hamster cells. The 656-amino acid receptor is homologous to the gibbon ape leukemia virus receptor at both hydrophobic termini but is highly divergent in the central hydrophilic region. Both receptors appear to be integral membrane proteins having multiple membrane-spanning …