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Full-Text Articles in Medicine and Health Sciences
Effects Of Ecotropic Murine Retroviruses On The Dual-Function Cell Surface Receptor/Basic Amino Acid Transporter, Hao Wang, Esther Dechant, Michael Kavanaugh, R. Alan North, David Kabat
Effects Of Ecotropic Murine Retroviruses On The Dual-Function Cell Surface Receptor/Basic Amino Acid Transporter, Hao Wang, Esther Dechant, Michael Kavanaugh, R. Alan North, David Kabat
Biomedical and Pharmaceutical Sciences Faculty Publications
The widely expressed Na(+)-independent transporter for basic amino acids (system y+) is the cell surface receptor (ecoR) for ecotropic host-range mouse retroviruses (murine leukemia viruses (MuLVs)), a class of retroviruses that naturally infects only mice or rats. Accordingly, expression of mouse ecoR cDNA in mink CCL64 fibroblasts yields cells (CEN cells) that have y+ transporter activity above the endogenous background and that bind and are infected by ecotropic MuLVs. The effect of ecotropic MuLV infection on expression of y+ transporter was analyzed in mouse and in mink CEN fibroblasts. Chronic infection with ecotropic MuLVs caused 50-70% loss (down-modulation) of mouse …
Electrogenic Uptake Of Gamma-Aminobutyric Acid By A Cloned Transporter Expressed In Xenopus Oocytes, Michael Kavanaugh, Jeffrey L. Arriza, R. Alan North, Susan G. Amara
Electrogenic Uptake Of Gamma-Aminobutyric Acid By A Cloned Transporter Expressed In Xenopus Oocytes, Michael Kavanaugh, Jeffrey L. Arriza, R. Alan North, Susan G. Amara
Biomedical and Pharmaceutical Sciences Faculty Publications
GAT-1, a gamma-aminobutyric acid (GABA) transporter cloned from rat brain, was expressed in Xenopus oocytes. Voltage-clamp measurements showed concentration-dependent, inward currents in response to GABA (K0.5 4.7 microM). The transport current required extracellular sodium and chloride ions; the Hill coefficient for chloride was 0.7, and that for sodium was 1.7. Correlation of current and [3H]GABA uptake measurements indicate that flux of one positive charge occurs per molecule of GABA transported. Membrane hyperpolarization from -40 to -100 mV increased the transport current approximately 3-fold. The results indicate that the transport of one molecule of GABA involves the co-transport of two sodium …
Cooperative Interactions Among Subunits Of A Voltage-Dependent Potassium Channel. Evidence From Expression Of Concatenated Cdnas, Raymond S. Hurst, Michael Kavanaugh, Jerrel Yakel, John P. Adelman, R. Alan North
Cooperative Interactions Among Subunits Of A Voltage-Dependent Potassium Channel. Evidence From Expression Of Concatenated Cdnas, Raymond S. Hurst, Michael Kavanaugh, Jerrel Yakel, John P. Adelman, R. Alan North
Biomedical and Pharmaceutical Sciences Faculty Publications
Four copies of the coding sequence for a voltage-dependent potassium channel (RBK1, rat Kv1.1) were ligated contiguously and transcribed in vitro. The resulting RNA encodes four covalently linked subunit domains ([4]RBK1). Injection of this RNA into Xenopus oocytes resulted in the expression of voltage-dependent potassium currents. A single amino acid substitution, Tyr-->Val, located within the outer mouth of the pore, introduced into the equivalent position of any of the four domains, reduced affinity for external tetraethylammonium by approximately the same amount. In constructs containing 0, 1, 2, 3, or 4 Tyr residues the free energy of binding tetraethylammonium was …