A family of glutamate receptor genes: Evidence for the formation of heteromultimeric receptors with distinct channel properties

Abstract

SummaryWe have isolated two cDNA clones (GluR-K2 and GluR-K3) that share considerable sequence identity with the previously described glutamate receptor subunit, GluR-K1. The three glutamate receptor subunits show significant sequence conservation with the glutamine binding component of the glutamine permease of E. coli. Each of these clones encodes a channel responsive to both kainate and AMPA. The coexpression of GluR-K2 with either GluR-K3 or GluR-K1 results in the formation of channels whose current-voltage relationships differ from those of the individual subunits alone and more closely approximate the properties of kainate receptors in neurons. These observations indicate that the kainate/quisqualate receptors are encoded by a family of genes and are likely to be composed of hetero-oligomers of at least two distinct subunits.

Organization of Ionotropic Glutamate Receptors at Dendrodendritic Synapses in the Rat Olfactory Bulb

“…Native AMPA receptors are believed to be hetero-oligomeric complexes assembled from four different subunits, named GluR1-GluR4 (Hollmann et al, 1989;Boulter et al, 1990;Keinänen et al, 1990;Nakanishi et al, 1990) (for review, see Hollmann and Heinemann, 1994). All of the cloned AMPA receptor subunits are expressed in the olfactory bulb (Keinänen et al, 1990;Petralia and Wenthold, 1992;Molnar et al, 1993;Martin et al, 1993;Giustetto et al, 1997;Montague and Greer, 1999), but their precise localization within the olfactory synaptic circuits has not been determined.…”

Multiple signaling pathways involved in stimulation of osteoblast differentiation by N-methyl-D-aspartate receptors activation in vitro

“…Extracellular levels of glutamate are determined by the glutamate transporter [1,2] . The diverse actions of L-glutamate in the CNS result from the existence of multiple glutamate receptors (GluR).…”

Impairment of the Ca2+‐Permeable AMPA/Kainate Receptors by Lead Exposure in Organotypic Rat Hippocampal Slice Cultures

“…Previous studies have found that activation of the NMDA receptors results in activation of an ion channel permeable to Ca 2π , while activation of the non-NMDA receptors was found to activate channels permeable only to Na π and K π (MacDermott et al 1986;Monaghan et al 1989;Betz 1990). Recent experiments have found that many of non-NMDA receptors appear to activate channels that are also permeable to Ca 2π (Murphy & Miller 1989;Barnard & Henley 1990;Glaum et al 1990;Nakanishi et al 1990;Gilbertson et al 1991;Hollman et al 1991). Exposure of hippocampal neurones in dissociated cultures to non-NMDA agonists resulted in marked increase in intracellular calcium (Iino et al 1990;Ogura et al 1990).…”

“…Three main subgroups of ionotropic receptors have been identified: those activated by N-methyl-D-aspartate (NMDA receptors), those activated by kainate (kainate receptors) and those activated by a-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA receptors) (Watkins & Evans 1981;Mayer & Westbrook 1987;Monaghan et al 1989;Barnard & Henley 1990). The NMDA receptorsactivated channels and several of the non-NMDA (AMPA/ kainate) receptors-activated channels are permeable to calcium (Barnard & Henley 1990;Betz 1990;Nakanishi et al 1990). Many of the neurotoxic effects of lead could be related to the ability of lead to interfere with the action of calcium as a regulator of cell function.…”