Modulation of neurosteroid potentiation by protein kinases at synaptic- and extrasynaptic-type GABAA receptors
| Autor: | Adams, Joanna M., Thomas, Philip, Smart, Trevor G. |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2015 |
| Předmět: |
Patch-Clamp Techniques
Blotting Western Transfection Article Protein kinase Cellular and Molecular Neuroscience Extrasynaptic GABAA receptors Mice PMA phorbol-12-myristate-13-acetate polycyclic compounds Neurosteroid Animals Humans Synaptic GABAA receptors Phosphorylation Desoxycorticosterone Protein Kinase Inhibitors Pharmacology Neurons Neurotransmitter Agents Neural Inhibition Receptors GABA-A Staurosporine THDOC tetrahydro-deoxycorticosterone THIP 4 5 6 7-tetrahydroisothiazolo-[5 4-c]pyridine-3-ol HEK293 Cells nervous system BIM-I bisindolylmaleimide I Synapses Protein Kinases hormones hormone substitutes and hormone antagonists |
| Zdroj: | Neuropharmacology |
| ISSN: | 1873-7064 0028-3908 |
| Popis: | GABAA receptors are important for inhibition in the CNS where neurosteroids and protein kinases are potent endogenous modulators. Acting individually, these can either enhance or depress receptor function, dependent upon the type of neurosteroid or kinase and the receptor subunit combination. However, in vivo, these modulators probably act in concert to fine-tune GABAA receptor activity and thus inhibition, although how this is achieved remains unclear. Therefore, we investigated the relationship between these modulators at synaptic-type α1β3γ2L and extrasynaptic-type α4β3δ GABAA receptors using electrophysiology. For α1β3γ2L, potentiation of GABA responses by tetrahydro-deoxycorticosterone was reduced after inhibiting protein kinase C, and enhanced following its activation, suggesting this kinase regulates neurosteroid modulation. In comparison, neurosteroid potentiation was reduced at α1β3S408A,S409Aγ2L receptors, and unaltered by PKC inhibitors or activators, indicating that phosphorylation of β3 subunits is important for regulating neurosteroid activity. To determine whether extrasynaptic-type GABAA receptors were similarly modulated, α4β3δ and α4β3S408A,S409Aδ receptors were investigated. Neurosteroid potentiation was reduced at both receptors by the kinase inhibitor staurosporine. By contrast, neurosteroid-mediated potentiation at α4S443Aβ3S408A,S409Aδ receptors was unaffected by protein kinase inhibition, strongly suggesting that phosphorylation of α4 and β3 subunits is required for regulating neurosteroid activity at extrasynaptic receptors. Western blot analyses revealed that neurosteroids increased phosphorylation of β3S408,S409 implying that a reciprocal pathway exists for neurosteroids to modulate phosphorylation of GABAA receptors. Overall, these findings provide important insight into the regulation of GABAA receptors in vivo, and into the mechanisms by which GABAergic inhibitory transmission may be simultaneously tuned by two endogenous neuromodulators. This article is part of the Special Issue entitled ‘GABAergic Signaling in Health and Disease’. Highlights • Neurosteroid potentiation at GABAA receptors is modulated by protein kinase activity. • Synaptic-type α1β3γ2L receptor potentiation is up or down-regulated by PKC activity. • PKC-mediated modulation occurs via β3 subunit S408 & S409 phosphorylation. • Potentiation at extrasynaptic-type α4β3δ receptors is additionally regulated by α4S443. • Neurosteroids facilitate phosphorylation of GABAA receptors via βS408,S409. |
| Databáze: | OpenAIRE |
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