GluR7 is an essential subunit of presynaptic kainate autoreceptors at hippocampal mossy fiber synapses.
Proceedings of the National Academy of Sciences. 2007-07-09; 104(29): 12181-12186
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1. Proc Natl Acad Sci U S A. 2007 Jul 17;104(29):12181-6. Epub 2007 Jul 9.
GluR7 is an essential subunit of presynaptic kainate autoreceptors at hippocampal
mossy fiber synapses.
Pinheiro PS(1), Perrais D, Coussen F, Barhanin J, Bettler B, Mann JR, Malva JO,
Heinemann SF, Mulle C.
(1)Laboratoire Physiologie Cellulaire de la Synapse, Centre National de la
Recherche Scientifique, Bordeaux Neuroscience Institute, University of Bordeaux,
33077 Bordeaux Cedex, France.
Presynaptic ionotropic glutamate receptors are emerging as key players in the
regulation of synaptic transmission. Here we identify GluR7, a kainate receptor
(KAR) subunit with no known function in the brain, as an essential subunit of
presynaptic autoreceptors that facilitate hippocampal mossy fiber synaptic
transmission. GluR7(-/-) mice display markedly reduced short- and long-term
synaptic potentiation. Our data suggest that presynaptic KARs are GluR6/GluR7
heteromers that coassemble and are localized within synapses. We show that
recombinant GluR6/GluR7 KARs exhibit low sensitivity to glutamate, and we provide
evidence that presynaptic KARs at mossy fiber synapses are likely activated by
high concentrations of glutamate. Overall, from our data, we propose a model
whereby presynaptic KARs are localized in the presynaptic active zone close to
release sites, display low affinity for glutamate, are likely Ca(2+)-permeable,
are activated by single release events, and operate within a short time window to
facilitate the subsequent release of glutamate.
PMID: 17620617 [Indexed for MEDLINE]