Endoplasmic Reticulum-associated Degradation Controls Cell Surface Expression of γ-Aminobutyric Acid, Type B Receptors

Zemoura, Khaled; Schenkel, Marisa; Acuña, Mario A.; Yévenes, Gonzalo E.; Zeilhofer, Hanns Ulrich; Benke, Dietmar

doi:10.1074/jbc.m113.514745

Cited by 30 publications

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References 33 publications

(37 reference statements)

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“…The two main cellular degradation systemsproteasomes and lysosomes-control the abundance of GABA B receptors in distinct cellular compartments in response to the activity state of the neuron [10,11,17]. In the ER, the amount of newly synthetized GABA B receptors destined for trafficking to the plasma membrane is regulated by proteasomal degradation via the ERAD machinery [10], whereas cell surface GABA B receptors are degraded in lysosomes [12][13][14][15][16]. Both degradation pathways require [10] and Lys-63-linked ubiquitination of GABA B1 at several sites sorts the receptors to lysosomes [17].…”

Section: Discussionmentioning

confidence: 99%

“…In the ER, the amount of newly synthetized GABA B receptors destined for trafficking to the plasma membrane is regulated by proteasomal degradation via the ERAD machinery [10], whereas cell surface GABA B receptors are degraded in lysosomes [12][13][14][15][16]. Both degradation pathways require [10] and Lys-63-linked ubiquitination of GABA B1 at several sites sorts the receptors to lysosomes [17]. Interestingly, Lys-48-and Lys-63-linked ubiquitination appears to be largely segregated to GABA B2 and GABA B1 [10,17], respectively, which might be explained by a selective interaction of the subunits with the respective E3 ligases.…”

Section: Discussionmentioning

confidence: 99%

“…The two main cellular protein degradation systems, which are proteasomes and lysosomes, contribute to the regulation of cell surface GABA B receptors in different cellular compartments. In the endoplasmic reticulum (ER), the amount of newly synthesized GABA B receptors that are trafficked to the cell surface is determined by proteasomal degradation via the ER-associated degradation (ERAD) machinery [10]. The activity state of the neuron controls the rate of Lys-48-linked ubiquitination of the GABA B2 subunit required for proteasomal receptor degradation [11].…”

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Ca2+/Calmodulin-Dependent Protein Kinase II (CaMKII) β-Dependent Phosphorylation of GABAB1 Triggers Lysosomal Degradation of GABAB Receptors via Mind Bomb-2 (MIB2)-Mediated Lys-63-Linked Ubiquitination

et al. 2018

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The G protein-coupled GABA B receptors, constituted from GABA B1 and GABA B2 subunits, are important regulators of neuronal excitability by mediating long-lasting inhibition. One factor that determines receptor availability and thereby the strength of inhibition is regulated protein degradation. GABA B receptors are constitutively internalized from the plasma membrane and are either recycled to the cell surface or degraded in lysosomes. Lys-63-linked ubiquitination mediated by the E3 ligase Mind bomb-2 (MIB2) is the signal that sorts GABA B receptors to lysosomes. However, it is unknown how Lys-63-linked ubiquitination and thereby lysosomal degradation of the receptors is regulated. Here, we show that Ca 2+ /calmodulin-dependent protein kinase II (CaMKII) promotes MIB2-mediated Lys-63-linked ubiquitination of GABA B receptors. We found that inhibition of CaMKII in cultured rat cortical neurons increased cell surface GABA B receptors, whereas overexpression of CaMKIIβ, but not CaMKIIα, decreased receptor levels. This effect was conveyed by Lys-63-linked ubiquitination of GABA B1 at multiple sites mediated by the E3 ligase MIB2. Inactivation of the CaMKII phosphorylation site on GABA B1 (Ser-867) strongly reduced Lys-63-linked ubiquitination of GABA B receptors and increased their cell surface expression, whereas the phosphomimetic mutant GABA B1 (S867D) exhibited strongly increased Lys-63-linked ubiquitination and reduced cell surface expression. Finally, triggering lysosomal degradation of GABA B receptors by sustained activation of glutamate receptors, a condition occurring in brain ischemia, was accompanied with a massive increase of GABA B1 (Ser-867) phosphorylation-dependent Lys-63-linked ubiquitination of GABA B receptors. These findings indicate that CaMKIIβ-dependent Lys-63-linked ubiquitination of GABA B1 at multiple sites controls sorting of GABA B receptors to lysosomes for degradation under physiological and pathological condition.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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confidence: 99%

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Ca2+/Calmodulin-Dependent Protein Kinase II (CaMKII) β-Dependent Phosphorylation of GABAB1 Triggers Lysosomal Degradation of GABAB Receptors via Mind Bomb-2 (MIB2)-Mediated Lys-63-Linked Ubiquitination

et al. 2018

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“…GABA B receptor plasma membrane availability is controlled by mechanisms involving an ER retention motif and assemblydependent ER export. Blocking proteasomal activity (mediated by ER-associated degradation) and inactivation of ubiquitination sites considerably enhances total and cell surface expression of GABA B receptors (Zemoura et al, 2013). Such mechanisms are not restricted to GABA B receptors.…”

Section: B Chaperones Play An Essential Role In Cell Surface Trafficmentioning

confidence: 99%

Molecular Pharmacology ofδ-Opioid Receptors

et al. 2016

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“…Three of those residues (Lys-887 and Lys-905 on GABA B(1b) and Lys-767 on GABA B(2) ) had been found to be ubiquitinated in the human brain (34) and both Lys-767 and Lys-771 have been linked to proteasomal degradation of GABA B through a mechanism involving Rpt6 (25,45). Lys-893 and Lys-900, however, represent novel ubiquitination sites revealed by our study.…”

Section: Discussionmentioning

confidence: 48%

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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Endoplasmic Reticulum-associated Degradation Controls Cell Surface Expression of γ-Aminobutyric Acid, Type B Receptors

Cited by 30 publications

References 33 publications

Ca2+/Calmodulin-Dependent Protein Kinase II (CaMKII) β-Dependent Phosphorylation of GABAB1 Triggers Lysosomal Degradation of GABAB Receptors via Mind Bomb-2 (MIB2)-Mediated Lys-63-Linked Ubiquitination

Ca2+/Calmodulin-Dependent Protein Kinase II (CaMKII) β-Dependent Phosphorylation of GABAB1 Triggers Lysosomal Degradation of GABAB Receptors via Mind Bomb-2 (MIB2)-Mediated Lys-63-Linked Ubiquitination

Molecular Pharmacology ofδ-Opioid Receptors

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

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