Modulation of the neuronal glutamate transporter EAAC1 by the interacting protein GTRAP3-18.

Excitatory amino-acid carrier 1 (EAAC1) is a high-affinity Na+-dependent L-glutamate/D,L-aspartate cell-membrane transport protein. It is expressed in brain as well as several non-nervous tissues. In brain, EAAC1 is the primary neuronal glutamate transporter. It has a polarized distribution in cells and mainly functions perisynaptically to transport glutamate from the extracellular ...
environment. In the kidney it is involved in renal acidic amino-acid re-absorption and amino-acid metabolism. Here we describe the identification and characterization of an EAAC1-associated protein, GTRAP3-18. Like EAAC1, GTRAP3-18 is expressed in numerous tissues. It localizes to the cell membrane and cytoplasm, and specifically interacts with carboxy-terminal intracellular domain of EAAC1. Increasing the expression of GTRAP3-18 in cells reduces EAAC1-mediated glutamate transport by lowering substrate affinity. The expression of GTRAP3-18 can be upregulated by retinoic acid, which results in a specific reduction of EAAC1-mediated glutamate transport. These studies show that glutamate transport proteins can be regulated potently and that GTRAP can modulate the transport functions ascribed to EAAC1. GTRAP3-18 may be important in regulating the metabolic function of EAAC1.
Mesh Terms:
ATP-Binding Cassette Transporters, Amino Acid Transport System X-AG, Animals, Biological Transport, Brain, Carrier Proteins, Cell Line, Cloning, Molecular, Excitatory Amino Acid Transporter 3, Glutamate Plasma Membrane Transport Proteins, Glutamic Acid, Membrane Proteins, Molecular Sequence Data, Precipitin Tests, Protein Binding, Protein Kinase C, Proteins, Rats, Recombinant Fusion Proteins, Symporters, Tissue Distribution, Tretinoin
Nature
Date: Mar. 01, 2001
Download Curated Data For This Publication
3143
Switch View:
  • Interactions 2