Gating and permeation of kainate receptors: differences unveiled.
Kainate receptors (KARs) represent, together with α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and N-methyl D-aspartate (NMDA) receptors, one of the three families of ionotropic glutamate receptors. Recent advances in the study of their biophysical properties have revealed a surprising diversity. KAR-mediated excitatory postsynaptic currents (EPSCs) are often much slower than AMPA receptor-mediated EPSCs, and this is probably due to the slow deactivation rate of KARs containing the GluK4 or GluK5 subunits. By contrast, GluK3-containing receptors, unlike other AMPA/kainate receptors, desensitize faster at low agonist concentrations, making these receptors insensitive to glutamate spillover from neighboring synapses. Moreover, KARs have a wide range of sensitivities to intracellular polyamines and consequently of voltage dependent activation. Finally, newly discovered associated proteins, such as Neto1 and 2, have marked effects on receptor properties, increasing further the potential diversity of KAR functional properties. Altogether, this functional diversity of KARs could have profound consequences on their ability to shape synaptic transmission under physiological and pathological conditions.
Perrais
David
D
Laboratoire Physiologie Cellulaire de la Synapse, CNRS UMR 5091, University of Bordeaux, 33077 Bordeaux, France. david.perrais@u-bordeaux2.fr
Veran
Julien
J
Mulle
Christophe
C
D002118:Calcium / Q000378:metabolism; D019706:Excitatory Postsynaptic Potentials / Q000502:physiology; D018698:Glutamic Acid / Q000378:metabolism; D006801:Humans; D015640:Ion Channel Gating; D009474:Neurons / Q000378:metabolism / Q000502:physiology; D018091:Receptors, AMPA / Q000378:metabolism*; D058468:Receptors, Ionotropic Glutamate / Q000378:metabolism; D018092:Kainic Acid Receptors / Q000378:metabolism*; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism; D015398:Signal Transduction; D013096:Spermine / Q000378:metabolism; D013569:Synapses / Q000502:physiology; D009435:Synaptic Transmission; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid / Q000378:metabolism
D002118:Calcium; D018698:Glutamic Acid; D018091:Receptors, AMPA; D058468:Receptors, Ionotropic Glutamate; D018092:Kainic Acid Receptors; D016194:Receptors, N-Methyl-D-Aspartate; D013096:Spermine; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid