Modulation of the neuronal glutamate transporter EAAT4 by two interacting proteins.
Glutamate is the main excitatory neurotransmitter in the mammalian central nervous system and is removed from the synaptic cleft by sodium-dependent glutamate transporters. To date, five distinct glutamate transporters have been cloned from animal and human tissue: GLAST (EAAT1), GLT-1 (EAAT2), EAAC1 (EAAT3), EAAT4, and EAAT5 (refs 1-5). GLAST and GLT-1 are localized primarily in astrocytes, whereas EAAC1 (refs 8, 9), EAAT4 (refs 9-11) and EAAT5 (ref 5) are neuronal. Studies of EAAT4 and EAAC1 indicate an extrasynaptic localization on perisynaptic membranes that are near release sites. This localization facilitates rapid glutamate binding, and may have a role in shaping the amplitude of postsynaptic responses in densely packed cerebellar terminals. We have used a yeast two-hybrid screen to identify interacting proteins that may be involved in regulating EAAT4--the glutamate transporter expressed predominately in the cerebellum--or in targeting and/or anchoring or clustering the transporter to the target site. Here we report the identification and characterization of two proteins, GTRAP41 and GTRAP48 (for glutamate transporter EAAT4 associated protein) that specifically interact with the intracellular carboxy-terminal domain of EAAT4 and modulate its glutamate transport activity.
Department of Neurology and Neuroscience, Johns Hopkins University, Baltimore, Maryland 21287, USA.
M
M
Jackson
W
W
Song
M Y
MY
Liu
L
L
Jin
M
M
Dykes-Hoberg
C I
CI
Lin
W J
WJ
Bowers
H J
HJ
Federoff
P C
PC
Sternweis
J D
JD
Rothstein
D000595:Amino Acid Sequence; D027322:Amino Acid Transport System X-AG; D000818:Animals; D001692:Biological Transport; D015152:Blotting, Northern; D015153:Blotting, Western; D002460:Cell Line; D003001:Cloning, Molecular; D027341:Excitatory Amino Acid Transporter 1; D027342:Excitatory Amino Acid Transporter 2; D050580:Excitatory Amino Acid Transporter 3; D050581:Excitatory Amino Acid Transporter 4; D050491:Glutamate Plasma Membrane Transport Proteins; D018698:Glutamic Acid / Q000378:metabolism*; D020662:Guanine Nucleotide Exchange Factors; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000378:metabolism; D008969:Molecular Sequence Data; D009474:Neurons / Q000378:metabolism*; D011233:Precipitin Tests; D011485:Protein Binding; D051381:Rats; D017470:Receptors, Glutamate / Q000235:genetics / Q000378:metabolism*; D064067:Rho Guanine Nucleotide Exchange Factors; D017386:Sequence Homology, Amino Acid; D013049:Spectrin / Q000235:genetics / Q000378:metabolism*; D027981:Symporters; D020798:Two-Hybrid System Techniques
C577234:ARHGEF11 protein, human; D027322:Amino Acid Transport System X-AG; C577237:Arhgef11 protein, rat; D027341:Excitatory Amino Acid Transporter 1; D027342:Excitatory Amino Acid Transporter 2; D050580:Excitatory Amino Acid Transporter 3; D050581:Excitatory Amino Acid Transporter 4; D050491:Glutamate Plasma Membrane Transport Proteins; D020662:Guanine Nucleotide Exchange Factors; D017470:Receptors, Glutamate; D064067:Rho Guanine Nucleotide Exchange Factors; C493398:Slc1a1 protein, rat; C493395:Slc1a2 protein, rat; C493392:Slc1a3 protein, rat; C493389:Slc1a6 protein, rat; C422723:Sptbn2 protein, rat; D027981:Symporters; D013049:Spectrin; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D018698:Glutamic Acid