Molecular mechanisms for the effect of mastoparan on G proteins in tissues of vertebrates and invertebrates

Ao, Shpakov; Pertseva, M. N.

doi:10.1007/s10517-006-0156-6

Cited by 12 publications

(5 citation statements)

References 11 publications

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“…In supporting the above result, addition of mastoparan, a G i/o protein agonist (1 μ m ) to the saline significantly increased the magnitude of LTD glu (peak amplitude at 48–52 min after the conjunctive stimuli, 64.6 ± 2.4%, n = 5). This drug directly activates G i/o protein by facilitating GTP binding to G i/o protein without the aid of G protein‐coupled receptors (Higashijima et al 1988; Shpakov & Pertseva, 2006). Thus, activation of G i/o protein is sufficient to enhance LTD glu .…”

Section: Resultsmentioning

confidence: 99%

Postsynaptic GABA_B receptor signalling enhances LTD in mouse cerebellar Purkinje cells

Kamikubo

Tabata

Kakizawa

et al. 2007

The Journal of Physiology

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Long-term depression (LTD) of excitatory transmission at cerebellar parallel fibre-Purkinje cell synapses is a form of synaptic plasticity crucial for cerebellar motor learning. Around the postsynaptic membrane of these synapses, B-type γ-aminobutyric acid receptor (GABA B R), a G i/o protein-coupled receptor for the inhibitory transmitter GABA is concentrated and closely associated with type-1 metabotropic glutamate receptors (mGluR1) whose signalling is a key factor for inducing LTD. We found that in cultured Purkinje cells, GABA B R activation enhanced LTD of a glutamate-evoked current (LTD glu ), increasing the magnitude of depression. It has been reported that parallel fibre-Purkinje cell synapses receive a micromolar level of GABA spilt over from the synaptic terminals of the neighbouring GABAergic interneurons. This level of GABA was able to enhance LTD glu . Our pharmacological analyses revealed that the βγ subunits but not the α subunit of G i/o protein mediated GABA B R-mediated LTD glu enhancement. G i/o protein activation was sufficient to enhance LTD glu . In this respect, LTD glu enhancement is clearly distinguished from the previously reported GABA B R-mediated augmentation of an mGluR1-coupled slow excitatory postsynaptic potential. Baclofen application for only the induction period of LTD glu was sufficient to enhance LTD glu , suggesting that GABA B R signalling may modulate mechanisms underlying LTD glu induction. Baclofen augmented mGluR1-coupled Ca 2+ release from the intracellular stores in a G i/o protein-dependent manner. Therefore, GABA B R-mediated LTD glu enhancement is likely to result from augmentation of mGluR1 signalling. Furthermore, pharmacological inhibition of GABA B R reduced the magnitude of LTD at parallel fibre-Purkinje cell synapses in cerebellar slices. These findings demonstrate a novel mechanism that would facilitate cerebellar motor learning.

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Section: Resultsmentioning

confidence: 99%

Postsynaptic GABA_B receptor signalling enhances LTD in mouse cerebellar Purkinje cells

Kamikubo

Tabata

Kakizawa

et al. 2007

The Journal of Physiology

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“…At 100 μM, IL4pSer415 and IL4pSer411 inhibited cAMP accumulation to a greater extent than IL4 or IL4pSer402. Mastoparan activates Gi/o proteins after passing across the cell membrane as an amphipathic α‐helix . As proof of principle, mastoparan evoked a dose‐dependent inhibition of cAMP accumulation that was identical to that of IL4pSer415.…”

Section: Resultsmentioning

confidence: 83%

“…Mastoparan activates Gi/o proteins after passing across the cell membrane as an amphipathic α-helix. [32][33][34] As proof of principle, mastoparan evoked a dose-dependent inhibition of cAMP accumulation that was identical to that of IL4pSer415.…”

Section: Cb 1 R Il4 Phosphopeptides Evoke Gi/o Protein Activation Amentioning

confidence: 98%

CB₁ cannabinoid receptor‐phosphorylated fourth intracellular loop structure‐function relationships

et al. 2018

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A peptide comprising the juxtamembrane C‐terminal intracellular loop 4 (IL4) of the CB1 cannabinoid receptor possesses three serine residues (Ser402, Ser411, and Ser415). We report the effect of Ser phosphorylation on the CB1 IL4 peptide conformation and cellular signaling functions using nuclear magnetic resonance spectroscopy, circular dichroism (CD), G protein activation, and cyclic adenosine monophosphate (cAMP) production. Phosphorylation at Ser residues induced helical structure in different environments. Helical content varies in the order of IL4p‐Ser411 > IL4pSer415 > IL4 > IL4pSer402. The efficacy of phosphorylated IL4 peptides in activating Go and Gi3 ([35S]GTPγS binding) and inhibiting cAMP accumulation in N18TG2 cells was correlated with helicity changes. Bradykinin treatment, which activates protein kinase C (PKC), augmented CB1‐mediated inhibition of cAMP accumulation, and this was reversed by a PKC inhibitor. We conclude that phosphorylation‐dependent alterations of helicity of CB1 IL4 peptides can augment G protein signaling.

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“…We further examined which subtype(s) of G-proteins may mediate the ATP effect. Internal dialysis with 10 μM mastoparan, a peptide activator of G i and G o 53 , for 8 min appeared to slow down the decay phases of the glycine currents of OFF-GCs, but did not change glycine current amplitudes (100.7 ± 3.69% of control, n = 5, P > 0.05), and addition of ATP persisted to suppress the currents to 63.7 ± 7.66% of control ( P < 0.001; Fig. 4C ).…”

Section: Resultsmentioning

confidence: 99%

Signaling mechanism for modulation by ATP of glycine receptors on rat retinal ganglion cells

Zhang

Zhou

et al. 2016

Sci Rep

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ATP modulates voltage- and ligand-gated channels in the CNS via the activation of ionotropic P2X and metabotropic P2Y receptors. While P2Y receptors are expressed in retinal neurons, the function of these receptors in the retina is largely unknown. Using whole-cell patch-clamp techniques in rat retinal slice preparations, we demonstrated that ATP suppressed glycine receptor-mediated currents of OFF type ganglion cells (OFF-GCs) dose-dependently, and the effect was in part mediated by P2Y1 and P2Y11, but not by P2X. The ATP effect was abolished by intracellular dialysis of a Gq/11 protein inhibitor and phosphatidylinositol (PI)-phospholipase C (PLC) inhibitor, but not phosphatidylcholine (PC)-PLC inhibitor. The ATP effect was accompanied by an increase in [Ca2+]i through the IP3-sensitive pathway and was blocked by intracellular Ca2+-free solution. Furthermore, the ATP effect was eliminated in the presence of PKC inhibitors. Neither PKA nor PKG system was involved. These results suggest that the ATP-induced suppression may be mediated by a distinct Gq/11/PI-PLC/IP3/Ca2+/PKC signaling pathway, following the activation of P2Y1,11 and other P2Y subtypes. Consistently, ATP suppressed glycine receptor-mediated light-evoked inhibitory postsynaptic currents of OFF-GCs. These results suggest that ATP may modify the ON-to-OFF crossover inhibition, thus changing action potential patterns of OFF-GCs.

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Molecular mechanisms for the effect of mastoparan on G proteins in tissues of vertebrates and invertebrates

Cited by 12 publications

References 11 publications

Postsynaptic GABA_B receptor signalling enhances LTD in mouse cerebellar Purkinje cells

Postsynaptic GABA_B receptor signalling enhances LTD in mouse cerebellar Purkinje cells

CB₁ cannabinoid receptor‐phosphorylated fourth intracellular loop structure‐function relationships

Signaling mechanism for modulation by ATP of glycine receptors on rat retinal ganglion cells

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Molecular mechanisms for the effect of mastoparan on G proteins in tissues of vertebrates and invertebrates

Cited by 12 publications

References 11 publications

Postsynaptic GABAB receptor signalling enhances LTD in mouse cerebellar Purkinje cells

Postsynaptic GABAB receptor signalling enhances LTD in mouse cerebellar Purkinje cells

CB1 cannabinoid receptor‐phosphorylated fourth intracellular loop structure‐function relationships

Signaling mechanism for modulation by ATP of glycine receptors on rat retinal ganglion cells

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Postsynaptic GABA_B receptor signalling enhances LTD in mouse cerebellar Purkinje cells

Postsynaptic GABA_B receptor signalling enhances LTD in mouse cerebellar Purkinje cells

CB₁ cannabinoid receptor‐phosphorylated fourth intracellular loop structure‐function relationships