Dephosphorylation of endogenous GABAB receptor R2 subunit and AMPK α subunits which were measured by in vitro method using transfer membrane

Kuramoto, Nobuyuki; Ito, Machiko; Saito, Yukinobu; Niihara, Hiroki; Tanaka, Natsuki; Yamada, Kenichi; Yamamura, Yusuke; Iwasaki, Kaname; Onishi, Yuki; Ogita, Kiyokazu

doi:10.1016/j.neuint.2012.12.003

Cited by 4 publications

(4 citation statements)

References 23 publications

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“…In such a model, non-ubiquitinated receptor would not bind to USP14 and would be targeted toward the recycling pathway, allowing reinsertion of the receptor in the plasma membrane and leading to the resensitization of the cells to GABA stimulation. Interestingly, glutamate has been shown to promote internalization (14) and down-regulation of GABA B (15) that involves a balance between receptor recycling and degradation (49) in which ubiquitination plays an important role, mirroring multiple elements from our proposed model. Possible activation of PKC by glutamate or others physiological stimuli could provide a general mechanism of regulation of GABA B activity, as we have observed that stimulation of endog-enous muscarinic receptors with carbachol also leads to increased GABA B ubiquitination (data not shown).…”

Section: Discussionsupporting

confidence: 61%

Post-endocytotic Deubiquitination and Degradation of the Metabotropic γ-Aminobutyric Acid Receptor by the Ubiquitin-specific Protease 14

Lahaie

Králíková

Prézeau

et al. 2016

Journal of Biological Chemistry

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Mechanisms controlling the metabotropic ␥-aminobutyric acid receptor (GABA B ) cell surface stability are still poorly understood. In contrast with many other G protein-coupled receptors (GPCR), it is not subject to agonist-promoted internalization, but is constitutively internalized and rapidly downregulated. In search of novel interacting proteins regulating receptor fate, we report that the ubiquitin-specific protease 14 (USP14) interacts with the GABA B(1b) subunit's second intracellular loop. Probing the receptor for ubiquitination using bioluminescence resonance energy transfer (BRET), we detected a constitutive and phorbol 12-myristate 13-acetate (PMA)-induced ubiquitination of the receptor at the cell surface. PMA also increased internalization and accelerated receptor degradation. Overexpression of USP14 decreased ubiquitination while treatment with a small molecule inhibitor of the deubiquitinase (IU1) increased receptor ubiquitination. Treatment with the internalization inhibitor Dynasore blunted both USP14 and IU1 effects on the receptor ubiquitination state, suggesting a post-endocytic site of action. Overexpression of USP14 also led to an accelerated degradation of GABA B in a catalytically independent fashion. We thus propose a model whereby cell surface ubiquitination precedes endocytosis, after which USP14 acts as an ubiquitin-binding protein that targets the ubiquitinated receptor to lysosomal degradation and promotes its deubiquitination.G protein-coupled receptors (GPCRs) 5 are the largest family of cell-surface proteins in the human genome and represent the target of a large proportion of current pharmacological agents. Regulation of GPCR activity in response to different stimuli provides cells with important mechanisms to fine tune the response to natural ligands as well as drugs.For most GPCRs, desensitization results from agonist-promoted phosphorylation by second messenger-activated and GPCR kinases (GRK) (1), leading to ␤-arrestin-promoted uncoupling from the G protein and subsequent endocytosis. In contrast, the metabotropic ␥-aminobutyric acid receptor (GABA B ), an obligatory hetero-oligomer composed of two different 7TM proteins, GABA B(1) and GABA B(2) , which provides the metabotropic response to the inhibitory neurotransmitter GABA (2) , does not undergo ␤-arrestin engagement and receptor endocytosis following agonist stimulation. Two GRK isoforms (GRK4 and GRK5) (3) have been proposed to play a role in GABA B desensitization. In the case of GRK4, this effect was found to be independent of its kinase activity, as its regulator of G protein signaling (RGS) domain alone is sufficient for desensitization of the receptor (4). Also, in contrast with most GPCR, GABA B activity is not correlated with the overall phosphorylation state of the receptor. Agonist-promoted protein kinase C (PKC) phosphorylation decreases receptor activity (5) while phosphorylation by adenosine monophosphate activated-kinase (AMPK) on GABA B(2) serine 783 (6) and by protein kinase A on GABA B(2) serine 893 (...

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Section: Discussionsupporting

confidence: 61%

Post-endocytotic Deubiquitination and Degradation of the Metabotropic γ-Aminobutyric Acid Receptor by the Ubiquitin-specific Protease 14

Lahaie

Králíková

Prézeau

et al. 2016

Journal of Biological Chemistry

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“…[32][33][34] However, recent studies have shown that AMPK can be dephosphorylated by PP1 and PP2A, as well as PP2C. [35][36][37][38][39] S485 phosphorylation of AMPK α subunit is also one of the mechanisms of AMPK inactivation. [40][41][42] Berggreen et al 40 showed that phosphorylation of AMPK S485 by AKT (protein kinase B (PKB)) reduced T172 phosphorylation in fat cells, resulting in a 25% decrease in active AMPK α1.…”

Section: Dephosphorylationmentioning

confidence: 99%

Down-regulation of adenosine monophosphate–activated protein kinase activity: A driver of cancer

Liu

et al. 2017

Tumour Biol.

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Adenosine monophosphate-activated protein kinase (AMPK), a serine/threonine protein kinase, is known as "intracellular energy sensor and regulator." AMPK regulates multiple cellular processes including protein and lipid synthesis, cell proliferation, invasion, migration, and apoptosis. Moreover, AMPK plays a key role in the regulation of "Warburg effect" in cancer cells. AMPK activity is down-regulated in most tumor tissues compared with the corresponding adjacent paracancerous or normal tissues, indicating that the decline in AMPK activity is closely associated with the development and progression of cancer. Therefore, understanding the mechanism of AMPK deactivation during cancer progression is of pivotal importance as it may identify AMPK as a valid therapeutic target for cancer treatment. Here, we review the mechanisms by which AMPK is down-regulated in cancer.

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“…Several studies reported that AMPK activation is detrimental, since it enhances energy-consumptive pathways that further contribute to the death of injured neuronal cells [14][15][16]. Meanwhile, Kuramoto et al [17] suggested that AMPK leads to neuroprotection through functional modulation of the GABA B receptor. Besides the effects on neural apoptosis and mortality, AMPK has been reported to play a dual role in generation of new neurons; the divergent effects result from the duration and extent of AMPK activation [18,19].…”

mentioning

confidence: 99%

“…Meanwhile, Kuramoto et al . suggested that AMPK leads to neuroprotection through functional modulation of the GABA B receptor. Besides the effects on neural apoptosis and mortality, AMPK has been reported to play a dual role in generation of new neurons; the divergent effects result from the duration and extent of AMPK activation .…”

mentioning

confidence: 99%

Inhibition of miRNA‐27b enhances neurogenesis via AMPK activation in a mouse ischemic stroke model

et al. 2019

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Stroke is a leading cause of death and disability, but treatment options remain limited. Recent studies have suggested that cerebral ischemia‐induced neurogenesis plays a vital role in post‐stroke repair. Overactivation of AMP ‐activated protein kinase ( AMPK ), a master sensor of energy balance, has been reported to exacerbate neuron apoptosis, but the role of chronic AMPK stimulus in post‐stroke recovery remains unclear. Micro RNA s have emerged as regulators of neurogenesis and have been reported to be involved in neurological function. In this study, we verified that miR‐27b directly targets AMPK and inhibits AMPK expression. In cultured neural stem cells, miR‐27b inhibitor improved proliferation and differentiation via the AMPK signaling pathway, but did not have an obvious effect on cell viability under oxygen and glucose deprivation conditions. In a mouse middle cerebral artery occlusion model, administration of miR‐27b inhibitor significantly enhanced behavioral function recovery and spatial memory. Up‐regulation of neurogenesis was observed both in the subventricular zone and in the hippocampal dentate gyrus. Collectively, our data suggest that miR‐27b inhibition promotes recovery after ischemic stroke by regulating AMPK activity. These findings may facilitate the development of novel therapeutic strategies for stroke.

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Dephosphorylation of endogenous GABAB receptor R2 subunit and AMPK α subunits which were measured by in vitro method using transfer membrane

Cited by 4 publications

References 23 publications

Post-endocytotic Deubiquitination and Degradation of the Metabotropic γ-Aminobutyric Acid Receptor by the Ubiquitin-specific Protease 14

Post-endocytotic Deubiquitination and Degradation of the Metabotropic γ-Aminobutyric Acid Receptor by the Ubiquitin-specific Protease 14

Down-regulation of adenosine monophosphate–activated protein kinase activity: A driver of cancer

Inhibition of miRNA‐27b enhances neurogenesis via AMPK activation in a mouse ischemic stroke model

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