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Full-Text Articles in Medicine and Health Sciences
Isolation Of Current Components And Partial Reaction Cycles In The Glial Glutamate Transporter Eaat2, Thomas S. Otis, Michael Kavanaugh
Isolation Of Current Components And Partial Reaction Cycles In The Glial Glutamate Transporter Eaat2, Thomas S. Otis, Michael Kavanaugh
Biomedical and Pharmaceutical Sciences Faculty Publications
The kinetic properties of the excitatory amino acid transporter EAAT2 were studied using rapid applications of l-glutamate to outside-out patches excised from transfected human embryonic kidney 293 cells. In the presence of the highly permeant anion SCN−, pulses of glutamate rapidly activated transient anion channel currents mediated by the transporter. In the presence of the impermeant anion gluconate, glutamate pulses activated smaller currents predicted to result from stoichiometric flux of cotransported ions. Both anion and stoichiometric currents displayed similar kinetics, suggesting that anion channel gating and stoichiometric charge movements are linked to early transitions in the transport cycle. …
Arginine 447 Plays A Pivotal Role In Substrate Interactions In A Neuronal Glutamate Transporter, Annie Bendahan, Ayelet Armon, Navid Madani, Michael Kavanaugh, Baruch I. Kanner
Arginine 447 Plays A Pivotal Role In Substrate Interactions In A Neuronal Glutamate Transporter, Annie Bendahan, Ayelet Armon, Navid Madani, Michael Kavanaugh, Baruch I. Kanner
Biomedical and Pharmaceutical Sciences Faculty Publications
Glutamate transporters from the central nervous system play a crucial role in the clearance of the transmitter from the synaptic cleft. Glutamate is cotransported with sodium ions, and the electrogenic translocation cycle is completed by countertransport of potassium. Mutants that cannot interact with potassium are only capable of catalyzing electroneutral exchange. Here we identify a residue involved in controlling substrate recognition in the neuronal transporter EAAC-1 that transports acidic amino acids as well as cysteine. When arginine 447, a residue conserved in all glutamate transporters, is replaced by cysteine, transport of glutamate or aspartate is abolished, but sodium-dependent cysteine transport …
Pentameric Assembly Of A Neuronal Glutamate Transporter, Sepehr Eskandari, Michael Kreman, Michael Kavanaugh, Ernest M. Wright, Guido A. Zampighi
Pentameric Assembly Of A Neuronal Glutamate Transporter, Sepehr Eskandari, Michael Kreman, Michael Kavanaugh, Ernest M. Wright, Guido A. Zampighi
Biomedical and Pharmaceutical Sciences Faculty Publications
Freeze-fracture electron microscopy was used to study the structure of a human neuronal glutamate transporter (EAAT3). EAAT3 was expressed in Xenopus laevis oocytes, and its function was correlated with the total number of transporters in the plasma membrane of the same cells. Function was assayed as the maximum charge moved in response to a series of transmembrane voltage pulses. The number of transporters in the plasma membrane was determined from the density of a distinct 10-nm freeze-fracture particle, which appeared in the protoplasmic face only after EAAT3 expression. The linear correlation between EAAT3 maximum carrier-mediated charge and the total number …