Molecular cloning, gene structure, expression profile and functional characterization of the mouse glutamate transporter (EAAT3) interacting protein GTRAP3-18.
Glutamate is an important amino acid implicated in energy metabolism, protein biosynthesis and neurotransmission. The Na(+)-dependent high-affinity excitatory amino acid transporter EAAT3 (EAAC1) facilitates glutamate uptake into most cells. Recently, a novel rat EAAT3-interacting protein called GTRAP3-18 has been identified by a yeast two-hybrid screening. GTRAP3-18 functions as a negative modulator of EAAT3-mediated glutamate transport. In order to further understand the function and regulation of GTRAP3-18, we cloned the mouse orthologue to GTRAP3-18 and determined its gene structure and its expression pattern. GTRAP3-18 encodes a 188-residue hydrophobic protein whose sequence is highly conserved amongst vertebrates. Mouse and human GTRAP3-18 genes contain three exons separated by two introns. The GTRAP3-18 gene is found on mouse chromosome 6D3 and on human chromosome 3p14, a susceptibility locus for cancer and epilepsy. GTRAP3-18 protein and RNA were found both in neuronal rich regions of the brain and in non-neuronal tissues such as the kidney, heart and skeletal muscle. Mouse GTRAP3-18 inhibited EAAT3-mediated glutamate transport in a dose-dependent manner. These studies show that GTRAP3-18 is a ubiquitously expressed protein that functions as a negative regulator of EAAT3 function.
Department of Neuroscience, The Ohio State University, 4068 Graves Hall, 333 West 10th Avenue, Columbus, OH 43210-1239, USA.
Matthew E R
ME
Butchbach
Liching
L
Lai
Chien-liang Glenn
CL
Lin
D000595:Amino Acid Sequence; D027322:Amino Acid Transport System X-AG; D000818:Animals; D001483:Base Sequence; D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism*; D002460:Cell Line; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D050580:Excitatory Amino Acid Transporter 3; D020869:Gene Expression Profiling; D005796:Genes / Q000235:genetics; D050491:Glutamate Plasma Membrane Transport Proteins; D018698:Glutamic Acid / Q000187:drug effects / Q000493:pharmacokinetics; D006360:Heat-Shock Proteins; D015151:Immunoblotting; D007150:Immunohistochemistry; D008297:Male; D026901:Membrane Transport Proteins; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D012313:RNA / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D027981:Symporters
D027322:Amino Acid Transport System X-AG; C464502:Arl6ip5 protein, mouse; D002352:Carrier Proteins; D018076:DNA, Complementary; D050580:Excitatory Amino Acid Transporter 3; D050491:Glutamate Plasma Membrane Transport Proteins; D006360:Heat-Shock Proteins; D026901:Membrane Transport Proteins; C493399:Slc1a1 protein, mouse; D027981:Symporters; D018698:Glutamic Acid; D012313:RNA