Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Previous pharmacological studies have indicated the possible existence of functional interactions between opioidergic and glutamatergic neurons in the CNS. In the present study, [(3)H]AMPA binding and the expression of mRNAs encoding flip and flop variants of three subtypes of AMPA glutamate receptor GluR1-3 were examined by in situ hybridization technique in order to investigate whether there is a change in the AMPA receptor system of mice lacking the mu-opioid receptor. In the mu-opioid receptor knockout mice, [(3)H]AMPA binding was increased in the hippocampal CA1 and dentate gyrus, cortex, and caudate putamen compared with that of the wild-type animals. The expression of GluR1 flip mRNA was increased in the cortex and caudate putamen of mu-opioid receptor knockout mice. The expression of GluR1 flop mRNA was increased in the cortex, caudate putamen, and hippocampal CA1 layer of mu-opioid receptor knockout mice. The expression of GluR2 flip mRNA was decreased in the hippocampal dentate gyrus of mu-opioid receptor knockout mice. The expression of GluR2 flop was not altered in any regions studied. The expression of GluR3 flip was increased in the cortical area and caudate putamen of mu-opioid receptor knockout mice. The expression of GluR3 flop was increased in the cortical area, hippocampal CA3 area, and caudate putamen of mu-opioid receptor knockout mice. These results indicate that [(3)H]AMPA binding and the expression of GluR1-3 mRNA were increased in a region and subunit specific manner, and suggest that changes in the AMPA receptor system are accompanied by the absence of mu-opioid receptor gene.
Brain Res Mol Brain Res 2003 May 12
PMID:Regional specific increases of [3H]AMPA binding and mRNA expression of AMPA receptors in the brain of mu-opioid receptor knockout mice. 1275 13

1. AMPA receptor potentiators (ARPs) exhibit antidepressant-like activity in preclinical tests (for example, the forced swim test) that are highly predictive of efficacy in humans. Unlike most currently used antidepressants, ARPs do not elevate extracellular levels of biogenic amines (e.g., 5HT, NE) in prefrontal cortex at doses that are active in the forced swim test. 2. The present series of experiments examined the effects of combining the ARP, LY 392098, with biogenic amine-based antidepressants in the forced swim test. Male, NIH Swiss mice were placed in a cylinder of water and observed for attempted escape behaviors and immobility. 3. LY 392098 dose-dependently decreased immobility as did a range of classical antidepressants. At doses of LY 392098 below those that decreased immobility, this compound significantly increased the potency with which fluoxetine and citalopram (SSRI antidepressants), imipramine (tricyclic antidepressant), duoxetine (norepinephrine/serotonin uptake blocker), nisoxetine (norepinephrine uptake inhibitor), and rolipram (PDE4 inhibitor) decreased immobility in the forced swim test with potency shifts upward of 5-fold (fluoxetine, imipramine, and rolipram). Likewise, ineffective doses of the traditional antidepressants potentiated the effects LY 392098 with shifts in the dose-effect functions that were 10-fold or more for citalopram, fluoxetine, imipramine, and duloxetine. 4. Combined with other evidence for a role of AMPA receptors in the efficacy of antidepressants, the current data suggest that the addition of an ARP may augment the activity and perhaps the onset of the therapeutic effects of biogenic amine and second messenger-based antidepressants.
Cell Mol Neurobiol 2003 Jun
PMID:Enhancement of antidepressant potency by a potentiator of AMPA receptors. 1282 36

The full mechanisms underlying neuronal death following excitotoxic insult remain unclear, despite many in vivo and in vitro studies. Recent work has focused on various signaling molecules and pathways, normally strictly regulated, that can trigger death if perturbed. The transcription factor, E2F1 is pivotal in controlling cell death under stress situations. The current study aimed to investigate the role of this transcription factor in modulating neuronal death following kainic acid (KA) treatment of cultured mouse cerebellar granule cells (CGCs). KA-induced death of CGCs was attenuated by the selective KA/AMPA receptor antagonist CNQX, but not MK-801. Such neuronal death was caspase-3-independent and did not activate many known death genes, such as Fas receptor, caspase-8 and p38. However, hyperphosphorylation of Rb showed a transient increase which may lead to activation of E2F1. Indeed E2F1 +/+ and -/- CGCs showed a differential response to KA-mediated toxicity, in that E2F1 -/- neurons were significantly less susceptible to KA compared to E2F1 +/+ neurons, albeit both E2F1 +/+ and -/- neurons expressed similar levels of KA receptors and responded similarly to kainate antagonist, CNQX. Using selective inhibitors to CDKs, such as olomoucine, roscovitine and flavopiridol, and the inhibitor SB203580 to p38 MAPK, we ruled out the possibility that Rb inactivation through hyperphosphorylation was due to either upstream kinases. Therefore activation of Rb/E2F1 pathway appears to involve novel interactions yet to be elucidated.
Brain Res Mol Brain Res 2003 Aug 19
PMID:Involvement of the transcription factor E2F1/Rb in kainic acid-induced death of murine cerebellar granule cells. 1294 62

Ionotropic glutamate receptors (GluRs) function as an excitatory transmitter system in human brain, particularly in learning and memory. Development of small-molecule chemical ligands that selectively potentiate the ion channel activity of AMPA-subtype GluRs would hold promise for treating an exceptionally wide range of disorders including neurodegenerative diseases such as Alzheimer's. Toward this goal, we have obtained nearly complete main-chain NMR resonance assignments of the extracellular ligand-binding domain of GluR2, which enables us to investigate receptor-ligand interactions in physiological conditions at atomic detail. With our NMR structure-based methods, we have discovered several chemical compounds that bind specifically to the GluR2 protein. Notably, our initial lead compounds interact with GluR2 at sites near the interface of receptor dimerization, which plays a pivotal role in controlling receptor gating and desensitization. Our NMR structural analysis further reveals that the regions of GluR2 at the dimer interface exhibit distinct conformational dynamics as compared to the rest of the protein, which we hypothesize to be linked to the mechanisms by which the protein interacts with its ligand, either an agonist or antagonist. This newly discovered relationship of possibly coupling of ligand binding to receptor dimerization, gating and desensitization, which is being further validated, could serve as an excellent in vitro biophysical parameter to evaluate the potential biological effects of the chemical ligands being developed and optimized in our study.
J Mol Neurosci 2003
PMID:Structure-based rational design of chemical ligands for AMPA-subtype glutamate receptors. 1450 Oct 18

Chronic pain states arise from peripheral nerve injury and are inadequately treated with current analgesics. Using intrathecal drug administration in a rat model of neuropathic pain, we demonstrate that AMPA receptors play a role in the central sensitisation that is thought to underpin chronic pain. The GluR2 subunit of the AMPA receptor binds to a number of intracellular adapter proteins including GRIP, PICK1 and NSF, which may link the receptor to proteins with signalling, scaffolding and other roles. We implicate for the first time a possible role for GRIP, PICK1 and NSF in neuropathic sensitisation from experiments with cell-permeable blocking peptides mimicking their GluR2 interaction motifs and also demonstrate differential changes in expression of these proteins following peripheral nerve injury. These studies suggest a critical involvement of protein:protein complexes associated with the AMPA receptor in neuropathic pain, and the possibility that they may have potential as novel therapeutic targets.
Mol Cell Neurosci 2003 Sep
PMID:Specific involvement in neuropathic pain of AMPA receptors and adapter proteins for the GluR2 subunit. 1455 Jul 65

The properties of some glutamate receptors are modified by RNA editing. This post-transcriptional mechanism involves the enzymatic deamination of specific adenosines in the pre-mRNA of the glutamate receptors, performed by specific RNA adenosine deaminases (ADARs). This event gives rise to the substitution of a gene-encoded amino acid with a different one that modifies the physiological properties of the ion channel. Here we report an analysis of the editing levels of AMPA GluR2, and kainate GluR5 and GluR6 in a human teratocarcinoma cell line (NT2) during in vitro neural differentiation, in conjunction with an analysis of the expression levels of GluR and ADAR genes. The editing levels were analysed using a specific standardised assay based on sequence analysis. This assay can be performed on all editing sites with a high level of sensitivity and reproducibility. Whereas GluR gene expression increased during NT2 neural differentiation, the expression of ADAR genes may be detected at comparable levels even in undifferentiated NT2 cells, remaining relatively stable during the differentiation process. Furthermore, most of the glutamate receptor editing sites increased their editing levels during NT2 neural differentiation, suggesting that the level of ADAR mRNAs is not closely related to the variable editing levels detected in the GluRs analysed. In human brain tissues, the editing levels appeared finely modulated in the different areas, indicating the possible formation of ion channels with different functional properties, thus generating a complex tissue-specific regulation of receptors and modulation of excitatory stimuli.
Brain Res Mol Brain Res 2003 Oct 07
PMID:Glutamate receptor RNA editing: a molecular analysis of GluR2, GluR5 and GluR6 in human brain tissues and in NT2 cells following in vitro neural differentiation. 1455 51

The present project was designed to investigate the role of protein kinase A (PKA) and protein kinase C (PKC) in the regulation of phosphorylation of the GluR1 subunits of AMPA receptors in the spinal cord of rats after capsaicin injection. We found that after capsaicin injection, a significant upregulation of phosphorylated GluR1 both at Ser(831) and Ser(845) was detected on the side ipsilateral to the injection. Intrathecal treatment with a PKA inhibitor, H89 ([N-[2-((3-bromophenyl)-2-propenyl)amino)ethyl]-5-isoquinoline sulfonamide, HCl), or a PKC inhibitor, NPC15473 (2,6-diamino-N-([1-oxotridecyl)-2-piperidinyl]methyl)hexanamide), significantly blocked the increased phosphorylation at different serine sites without affecting the GluR1 protein itself. Our results suggest that increased phosphorylation of the GluR1 subunit of AMPA receptors contributes to central sensitization following acute peripheral inflammation, and the effect may occur at different phosphorylation sites through the activation of the PKA or PKC protein kinase cascades.
Brain Res Mol Brain Res 2003 Oct 21
PMID:Protein kinases regulate the phosphorylation of the GluR1 subunit of AMPA receptors of spinal cord in rats following noxious stimulation. 1455 67

The stimulation of C-fiber sensory neurons is known to induce activation of the ERK MAP kinase signaling pathway in the spinal cord dorsal horn. In this study we have elucidated some of the signaling components of C-fiber transmission responsible for ERK activation. Using an in vitro slice preparation of the mouse spinal cord dorsal horn, we compared the release of substance P (SP) and BDNF with the activation of ERK in postsynaptic neurons. We observed that primary afferent stimulation recruiting C-fibers was required for both SP and BDNF release and ERK activation in post-synaptic dorsal horn neurons. Glutamate transmission via NMDA and mGluR1 but not AMPA receptors was critical to this ERK activation. BDNF signaling via TrkB receptors but not SP signaling via NK(1) were also involved in ERK recruitment. In conclusion, glutamate and BDNF are the important C-fiber signaling components for ERK activation in dorsal horn neurons.
Mol Cell Neurosci 2003 Oct
PMID:The signaling components of sensory fiber transmission involved in the activation of ERK MAP kinase in the mouse dorsal horn. 1457 51

Human PPFIA1 (also known as LIP.1 or Liprin alpha1) gene, located within CCND1-FGF4-EMS1 amplicon at human chromosome 11q13.3, encodes KIF1A-binding protein, which is implicated in trafficking of LAR subfamily PTPases and AMPA-type glutamate receptors. Human PPFIA4 (AF034801) and rat Ppfia4 (AY057064) are 5'-truncated partial cDNAs, and the complete coding sequence of PPFIA4 ortholog of any species remained to be identified. Here, we determined the complete coding sequence of human PPFIA4 gene by using bioinformatics. Exons 1-12 of PPFIA4 gene were located within human genome sequence AC096632.3, while exons 11-29 within AL451082.6. PPFIA4-MYOG locus (human chromosome 1q32.1) was paralogous to PPFIA2-LIN7A-MYF5-MYF6 locus (12q21.31), which was also paralogous to PPFIA3-LIN7B locus (19q13.41). PPFIA4 (1186 aa) showed 70.9%, 67.1%, and 61.8% total-amino-acid identity with PPFIA2, PPFIA1, and PPFIA3, respectively. PPFIA family members consist of PFIH1, PFIH2, PFIH3, PFIH4 domains and three SAM (Sterile alpha motif) domains. C-terminal binding domain for GRIP proteins (VRTYSC motif) was present in PPFIA1, PPFIA2 and PPFIA3, but not in PPFIA4. Bipartite nuclear localization signal was included within PFIH4 domain. PFIH2 domain was identical to ERM or Smc domain. The region spanning PFIH2-PFIH3 domains is the binding domain for KIF1A. The region spanning SAM1-SAM3 domains is the binding domain for LAR subfamily PTPases and PPFIBP (Liprin beta) family proteins. This is the first report on comprehensive characterization of PPFIA4 belonging to the PPFIA family of kinesin-cargo linkers.
Int J Mol Med 2003 Dec
PMID:Identification and characterization of human PPFIA4 gene in silico. 1461 82

AMPA glutamate receptors play a crucial role in brain functions such as synaptic plasticity and development. We have studied the chemo-architecture of the AMPA glutamate receptor subtype GluR2/3 in the hamster visual cortex by immunocytochemistry and compared it with the distribution of the calcium-binding proteins, calbindin D28K and calretinin. Anti-GluR2/3-immunoreactive (IR) neurons were predominantly located in layers II/III, V, and VI, and the majority of the labeled neurons were round or oval. However, many pyramidal cells in layer V were also labeled. Two-color immunofluorescence revealed that none of the GluR2/3-IR neurons contained calbindin D28 K or calretinin. Thus specific layers of neurons express the GluR2/3 subunit and these do not correlate with expression of calbindin D28K and calretinin.
Mol Cells 2003 Oct 31
PMID:Immunocytochemical localization of neurons containing the AMPA GluR2/3 subunit in the hamster visual cortex. 1465 Dec 63


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