Document Type
Article
Publication Title
Journal of Biological Chemistry
Publication Date
1997
Volume
272
Issue
3
Disciplines
Medical Sciences | Medicine and Health Sciences | Pharmacy and Pharmaceutical Sciences
Abstract
Glutamate transporters maintain low synaptic concentrations of neurotransmitter by coupling uptake to flux of other ions. After cotransport of glutamic acid with Na+, the cycle is completed by countertransport of K+. We have identified an amino acid residue (glutamate 404) influencing ion coupling in a domain of the transporter implicated previously in kainate binding. Mutation of this residue to aspartate (E404D) prevents both forward and reverse transport induced by K+. Sodium-dependent transmitter exchange and a transporter-mediated chloride conductance are unaffected by the mutation, indicating that this residue selectively influences potassium flux coupling. The results support a kinetic model in which sodium and potassium are translocated in distinct steps and suggest that this highly conserved region of the transporter is intimately associated with the ion permeation pathway.
DOI
10.1074/jbc.272.3.1703
Rights
© 1997 by The American Society for Biochemistry and Molecular Biology, Inc.
Recommended Citation
Kavanaugh, Michael; Bendahan, Annie; Zerangue, Noa; Zhang, Yumin; and Kanner, Baruch I., "Mutation of an Amino Acid Residue Influencing Potassium Coupling in the Glutamate Transporter GLT-1 Induces Obligate Exchange" (1997). Biomedical and Pharmaceutical Sciences Faculty Publications. 55.
https://scholarworks.umt.edu/biopharm_pubs/55