High impact information on GluRIIA

• This was associated with a significant increase in the postsynaptic DGluR-IIA protein levels and a reduction in the junctional expression of the cell-adhesion molecule Fasciclin II [1].
• Here we show that large aggregates of translational components as well as messenger RNA of the postsynaptic glutamate receptor subunit DGluR-IIA are localized within subsynaptic compartments of larval neuromuscular junctions of Drosophila melanogaster [1].
• Electrophysiological recordings made in Xenopus oocytes that express DGluR-II revealed depolarizing responses to L-glutamate and L-aspartate but low sensitivity to quisqualate, alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA), and kainate [2].
• We hypothesized that presynaptic glutamate regulates postsynaptic ionotropic glutamate receptor number during synaptogenesis [3].
• The GluRIIa glutamate receptor is upregulated in pum mutants [4].

Biological context of GluRIIA

• DGluRIII is required for the synaptic localization of DGluRIIA and DGluRIIB and for synaptic transmission [5].
• This study opens the way for a further characterization of in vivo glutamate receptor assembly and trafficking using the efficient genetics of Drosophila [6].
• We cloned the gene encoding a second muscle-specific glutamate receptor, DGluRIIB, which is closely related to the previously identified DGluRIIA and located adjacent to it in the genome [7].
• Thus, editing at these sites would appear to involve a mechanism whereby the edited exon forms a base-paired secondary structure with the distant conserved noncoding sequences located in adjacent downstream introns, similar to the mechanism shown for A-to-I RNA editing of mammalian glutamate receptor subunits (GluRs) [8].
• We show that DGluR-II mRNA is first expressed at stage 12 of embryogenesis and that expression is detected in developing dorsal, lateral, and ventral somatic muscles within the next 2 hr [9].

Anatomical context of GluRIIA

• Differential localization of glutamate receptor subunits at the Drosophila neuromuscular junction [5].
• In third instar larvae DGluR-II mRNA is expressed in all body-wall muscle fibers [9].
• These results indicate that although the DGluR-II gene is expressed in somatic muscle cells it is not selectively expressed in nuclei near the synaptic site [9].
• By stage 16 DGluR-II mRNA is expressed in all somatic muscles and in pharyngeal muscles [9].
• An essential Drosophila glutamate receptor subunit that functions in both central neuropil and neuromuscular junction [10].

Associations of GluRIIA with chemical compounds

• RESULTS: There are thought to be two classes of glutamate receptors in the Drosophila NMJ: 1) receptors that contain the subunit GluRIIA, and 2) receptors that contain the subunit GluRIIB [11].
• Isoflurane did not affect postsynaptic glutamate receptor function detectably, in that the amplitudes, areas and decay times of spontaneous miniature EJCs were unchanged at any concentration [12].
• The specificity of the response was tested with a glutamate receptor antagonist (argiotoxin 636) [13].
• Sterol-enriched lipid rafts have been involved in Drosophila membrane signalling such as Hedgehog targeting and glutamate receptor ligand-affinity regulation [14].
• Interestingly, we identified two non-heat-shock protein genes that were specifically responsive to ethanol. glr-2 was the only glutamate receptor gene to be induced by ethanol [15].

Physical interactions of GluRIIA

• Coracle interacts with the C terminus of GluRIIA but not GluRIIB [16].

Regulatory relationships of GluRIIA

• Dock is not necessary for Pak localization but is necessary to restrict Pak signaling to control glutamate receptor abundance [17].

Other interactions of GluRIIA

• Consistently, we show that glutamate receptor mutants also have a higher number of T bars; this increase is suppressed by postsynaptic activation of CaMKII [18].
• We used a cDNA encoding a subunit of the Drosophila muscle glutamate receptor (DGluR-II) to determine the temporal and spatial expression pattern of the DGluR-II gene during embryogenesis and in larval muscle [9].

Analytical, diagnostic and therapeutic context of GluRIIA

• Molecular cloning of an invertebrate glutamate receptor subunit expressed in Drosophila muscle [2].
• To build foundation for future molecular biological and genetic studies, we studied kinetics of the glutamate receptor channel in embryonic Drosophila myotubes in culture using the patch clamp technique [19].
• In the NMJ of null brec mutants, all known glutamate receptor subunits are undetectable by immunocytochemistry, and all functional glutamate receptors are eliminated [10].

References