Regulation of native GABAA receptors by PKC and protein phosphatase activity

Kumar, Sandeep; Khisti, Rahul T.; Morrow, A. Leslie

doi:10.1007/s00213-005-0161-x

Cited by 20 publications

(21 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Because ethanol decreased the serine phosphorylation of GABA A receptors and increased the phosphorylation of NMDA receptors, it is likely that phosphorylation contributes to the effects of ethanol on these receptors. The observation that ethanol administration decreases serine phosphorylation of GABA A receptors is consistent with other studies showing that ethanol can increase GABA A receptor responses in brain tissue (Suzdak et al, 1986;Allan and Harris, 1987;Morrow et al, 1988) and phosphorylation can decrease GABA A receptor responses in brain tissue (Brandon et al, 2000;Kumar et al, 2005).…”

Section: Discussionsupporting

confidence: 89%

Differential Effects of Systemic Ethanol Administration on Protein Kinase Cϵ, γ, and β Isoform Expression, Membrane Translocation, and Target Phosphorylation: Reversal by Chronic Ethanol Exposure

Kumar

Lane

Morrow

2006

J Pharmacol Exp Ther

View full text Add to dashboard Cite

Systemic ethanol administration alters protein kinase C (PKC) activity in brain, but the effects of ethanol on the expression and translocation of specific isoforms are unknown. Rats were administered ethanol (2 g/kg i.p.) or saline and PKC levels were measured in the cytosolic and membrane fractions by Western blot analysis. PKC expression was increased in the cytosol and decreased in the membrane (P2) fraction of cerebral cortex at 10 min. At 60 min, expression of PKC in the P2 fraction was increased by 42.2 Ϯ 12%, but cytosolic levels were unchanged. In contrast, PKC␥ in the P2 fraction was decreased 32.7 Ϯ 7% at 60 min but not at 10 min post-ethanol administration. PKC␥ levels in the cytosol were reduced at 10 min post-ethanol administration and unchanged at 60 min. PKC␤ expression was increased 36 Ϯ 10 and 144 Ϯ 52% in the P2 fraction both at 10 and 60 min post-ethanol administration, whereas cytosolic levels were unchanged. Serine phosphorylation of GABA A receptor ␤-chain was reduced, and phosphorylation of N-methyl-Daspartate receptor NR1 subunit was increased 60 min following ethanol administration. There was no effect of acute ethanol administration on PKC isoform levels in the hippocampus. Ethanol challenge did not alter PKC isoform expression in the P2 fraction of cerebral cortex following chronic ethanol administration. These findings suggest that acute ethanol administration alters PKC synthesis and translocation in an isoform and brain region specific manner that leads to alterations in serine phosphorylation of receptors. Furthermore, chronic ethanol administration prevents ethanol-induced alterations in PKC expression in the P2 fraction, where PKC interacts with ethanolresponsive ion channels.

show abstract

Section: Discussionsupporting

confidence: 89%

Differential Effects of Systemic Ethanol Administration on Protein Kinase Cϵ, γ, and β Isoform Expression, Membrane Translocation, and Target Phosphorylation: Reversal by Chronic Ethanol Exposure

Kumar

Lane

Morrow

2006

J Pharmacol Exp Ther

View full text Add to dashboard Cite

show abstract

“…Calphostin C was added 15 min before the start of ethanol exposure. These doses have been shown to inhibit PKC activity and to alter GABA A receptor function in cortical synaptoneurosomes (Kumar et al, 2005). Calphostin C alone did not alter the expression of ␣1 subunits in the P2 fraction (Fig.…”

Section: Ethanol Exposure Reduces Zolpidem Enhancement Of Gaba-evoked CLmentioning

confidence: 83%

Ethanol Reduces GABA_A α1 Subunit Receptor Surface Expression by a Protein Kinase Cγ-Dependent Mechanism in Cultured Cerebral Cortical Neurons

Kumar

Suryanarayanan²,

Boyd³

et al. 2010

Mol Pharmacol

Self Cite

View full text Add to dashboard Cite

Prolonged ethanol exposure causes central nervous system hyperexcitability that involves a loss of GABAergic inhibition. We previously demonstrated that long-term ethanol exposure enhances the internalization of synaptic GABA A receptors composed of ␣1␤2/3␥2 subunits. However, the mechanisms of ethanol-mediated internalization are unknown. This study explored the effect of ethanol on surface expression of GABA A ␣1 subunit-containing receptors in cultured cerebral cortical neurons and the role of protein kinase C (PKC) ␤, ␥, and isoforms in their trafficking. Cultured neurons were prepared from rat pups on postnatal day 1 and maintained for 18 days. Cells were exposed to ethanol, and surface receptors were isolated by biotinylation and P2 fractionation, whereas functional analysis was conducted by whole-cell patch-clamp recording of GABAand zolpidem-evoked responses. Ethanol exposure for 4 h decreased biotinylated surface expression of GABA A receptor ␣1 subunits and reduced zolpidem (100 nM) enhancement of GABA-evoked currents. The PKC activator phorbol-12,13-dibutyrate mimicked the effect of ethanol, and the selective PKC inhibitor calphostin C prevented ethanol-induced internalization of these receptors. Ethanol exposure for 4 h also increased the colocalization and coimmunoprecipitation of PKC␥ with ␣1 subunits, whereas PKC␤/␣1 association and PKC/␣1 colocalization were not altered by ethanol exposure. Selective PKC␥ inhibition by transfection of selective PKC␥ small interfering RNAs blocked ethanol-induced internalization of GABA A receptor ␣1 subunits, whereas PKC␤ inhibition using pseudo-PKC␤ had no effect. These findings suggest that ethanol exposure selectively alters PKC␥ translocation to GABA A receptors and PKC␥ regulates GABA A ␣1 receptor trafficking after ethanol exposure.

show abstract

“…An interesting finding of different effect of heme deficiency on GABA neurotransmitter receptor subunit and glutamate receptor NMDA subunit may lead to better understanding of why heme-distorted metabolism results in certain clinical manifestations in patients. One of the possible explanations of this distinctive difference in effects for NMDA and GABA receptors could be related to regulation by different signaling pathways (Zhu et al, 2002;Kumar et al, 2005).…”

Section: Discussionmentioning

confidence: 99%

Heme Deficiency Is Associated with Senescence and Causes Suppression ofN-Methyl-d-aspartate Receptor Subunits Expression in Primary Cortical Neurons

Chernova

Nicotera²,

Smith³

2005

Mol Pharmacol

View full text Add to dashboard Cite

Heme is a crucial component of many pharmacological and toxicological processes, and studies have suggested that heme deficiency may play a role in cellular ageing. A model of ageing neurons was established using prolonged cultures of BALB/c mouse primary cortical neurons. Aged neurons displayed a senescent phenotype and a marked up-regulation of cathepsin-L expression. Down-regulation of the candidate neuronspecific genes for N-methyl-D-aspartate (NMDA) receptor subunits (NMDA1 and -⑀2) and neurofilament light peptide (NF-L) were found to be characteristic of the aging process as reported in vivo (Brain 40 -45, 2002). In contrast, the genes for the controlling enzymes of heme synthesis and degradation (5-aminolevulinate synthase 1 and heme oxygenase 1, respectively) were up-regulated, implying depletion of a regulatory heme pool. Inhibition of heme synthesis (by 70 -80%) at different enzymic steps by succinyl acetone and N-methylprotoporphyrin IX resulted in the earlier lowered expression of NMDA1 and -⑀2 and NF-L. Exogenous hemin added to heme-depleted cells rescued the expression of these neuron-specific genes. Culture of cortical neurons from BALB/c Fech m1Pas mutant mice demonstrating depressed heme synthesis showed premature senescence and reduced expression of NMDA1 and -⑀2 receptor subunits and NF-L compared with wild-type cells. Our findings suggest that reduced availability of heme in neurons associated with senescence may have significant effects on synaptic function.

show abstract

Regulation of native GABAA receptors by PKC and protein phosphatase activity

Cited by 20 publications

References 34 publications

Differential Effects of Systemic Ethanol Administration on Protein Kinase Cϵ, γ, and β Isoform Expression, Membrane Translocation, and Target Phosphorylation: Reversal by Chronic Ethanol Exposure

Differential Effects of Systemic Ethanol Administration on Protein Kinase Cϵ, γ, and β Isoform Expression, Membrane Translocation, and Target Phosphorylation: Reversal by Chronic Ethanol Exposure

Ethanol Reduces GABA_A α1 Subunit Receptor Surface Expression by a Protein Kinase Cγ-Dependent Mechanism in Cultured Cerebral Cortical Neurons

Heme Deficiency Is Associated with Senescence and Causes Suppression ofN-Methyl-d-aspartate Receptor Subunits Expression in Primary Cortical Neurons

Contact Info

Product

Resources

About

Regulation of native GABAA receptors by PKC and protein phosphatase activity

Cited by 20 publications

References 34 publications

Differential Effects of Systemic Ethanol Administration on Protein Kinase Cϵ, γ, and β Isoform Expression, Membrane Translocation, and Target Phosphorylation: Reversal by Chronic Ethanol Exposure

Differential Effects of Systemic Ethanol Administration on Protein Kinase Cϵ, γ, and β Isoform Expression, Membrane Translocation, and Target Phosphorylation: Reversal by Chronic Ethanol Exposure

Ethanol Reduces GABAA α1 Subunit Receptor Surface Expression by a Protein Kinase Cγ-Dependent Mechanism in Cultured Cerebral Cortical Neurons

Heme Deficiency Is Associated with Senescence and Causes Suppression ofN-Methyl-d-aspartate Receptor Subunits Expression in Primary Cortical Neurons

Contact Info

Product

Resources

About

Ethanol Reduces GABA_A α1 Subunit Receptor Surface Expression by a Protein Kinase Cγ-Dependent Mechanism in Cultured Cerebral Cortical Neurons