Glutamate‐101 is critical for the function of the sodium and chloride‐coupled GABA transporter GAT‐1

FEBS Letters

Su, Hailing²  Lester, Henry A.¹  Bendahan, Annie²  Kanner, Baruch I.²  Mager, Sela¹  Keshet, Gilmor I.² 

[1] Division of Biology, 156-29, California Institute of Technology, Pasadena, CA 91125, USA;Department of Biochemistry, Hadassah Medical School, The Hebrew University, P.O. Box 12272, Jerusalem 91120, Israel

关键词: GABA transport;    Conserved negatively-charged residues;    Heterologous expression;    Sodium binding;    Conformational changes;    GABA;    γ-aminobutyric acid;    TD;    transmembrane domain;   

DOI  :  10.1016/0014-5793(95)00859-8

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

We have investigated the possible role of selected negatively-charged amino acids of the sodium and chloride-coupled GABA transporter GAT-1 on sodium binding. These residues located adjacent to putative transmembrane domains and which are conserved throughout the large superfamily of neurotransmitter transporters were changed by site-directed mutagenesis. The functional consequences were that one of the residues, glutamate-101, was critical for transport. Its replacement by aspartate left only 1% of the activity, and no activity could be detected when it was replaced by other residues. Expression levels and targeting to the plasma membrane of the mutant transporters appeared normal. Transient sodium currents were not observed in the mutants, and increased sodium concentrations did not affect the percentage of wild type transport of the E101D mutant. It is concluded that residue glutamate-101 is critical for one or more of the conformational changes of GAT-1 during its transport cycle.

【 授权许可】

Unknown