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Fritzius T, Tureček R, Fernandez-Fernandez D, Isogai S, Rem PD, Kralikova M, Gassmann M, Bettler B. Preassembly of specific Gβγ subunits at GABA B receptors through auxiliary KCTD proteins accelerates channel gating. Biochem Pharmacol 2024:116176. [PMID: 38555036 DOI: 10.1016/j.bcp.2024.116176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Revised: 03/15/2024] [Accepted: 03/26/2024] [Indexed: 04/02/2024]
Abstract
GABAB receptors (GBRs) are G protein-coupled receptors for GABA, the main inhibitory neurotransmitter in the brain. GBRs regulate fast synaptic transmission by gating Ca2+ and K+ channels via the Gβγ subunits of the activated G protein. It has been demonstrated that auxiliary GBR subunits, the KCTD proteins, shorten onset and rise time and increase desensitization of receptor-induced K+ currents. KCTD proteins increase desensitization of K+ currents by scavenging Gβγ from the channel, yet the mechanism responsible for the rapid activation of K+ currents has remained elusive. In this study, we demonstrate that KCTD proteins preassemble Gβγ at GBRs. The preassembly obviates the need for diffusion-limited G protein recruitment to the receptor, thereby accelerating G protein activation and, as a result, K+ channel activation. Preassembly of Gβγ at the receptor relies on the interaction of KCTD proteins with a loop protruding from the seven-bladed propeller of Gβ subunits. The binding site is shared between Gβ1 and Gβ2, limiting the interaction of KCTD proteins to these particular Gβ isoforms. Substituting residues in the KCTD binding site of Gβ1 with those from Gβ3 hinders the preassembly of Gβγ with GBRs, delays onset and prolongs rise time of receptor-activated K+ currents. The KCTD-Gβ interface, therefore, represents a target for pharmacological modulation of channel gating by GBRs.
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Affiliation(s)
| | - Rostislav Tureček
- Department of Biomedicine, University of Basel, Basel, Switzerland; Department of Auditory Neuroscience, Institute of Experimental Medicine CAS, Prague, Czech Republic
| | | | - Shin Isogai
- Microbial Downstream Process Development, Lonza AG, Visp, Switzerland
| | - Pascal D Rem
- Department of Biomedicine, University of Basel, Basel, Switzerland
| | - Michaela Kralikova
- Department of Auditory Neuroscience, Institute of Experimental Medicine CAS, Prague, Czech Republic
| | - Martin Gassmann
- Department of Biomedicine, University of Basel, Basel, Switzerland
| | - Bernhard Bettler
- Department of Biomedicine, University of Basel, Basel, Switzerland.
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Dinamarca MC, Raveh A, Schneider A, Fritzius T, Früh S, Rem PD, Stawarski M, Lalanne T, Turecek R, Choo M, Besseyrias V, Bildl W, Bentrop D, Staufenbiel M, Gassmann M, Fakler B, Schwenk J, Bettler B. Complex formation of APP with GABA B receptors links axonal trafficking to amyloidogenic processing. Nat Commun 2019; 10:1331. [PMID: 30902970 PMCID: PMC6430795 DOI: 10.1038/s41467-019-09164-3] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Accepted: 02/21/2019] [Indexed: 12/30/2022] Open
Abstract
GABAB receptors (GBRs) are key regulators of synaptic release but little is known about trafficking mechanisms that control their presynaptic abundance. We now show that sequence-related epitopes in APP, AJAP-1 and PIANP bind with nanomolar affinities to the N-terminal sushi-domain of presynaptic GBRs. Of the three interacting proteins, selectively the genetic loss of APP impaired GBR-mediated presynaptic inhibition and axonal GBR expression. Proteomic and functional analyses revealed that APP associates with JIP and calsyntenin proteins that link the APP/GBR complex in cargo vesicles to the axonal trafficking motor. Complex formation with GBRs stabilizes APP at the cell surface and reduces proteolysis of APP to Aβ, a component of senile plaques in Alzheimer's disease patients. Thus, APP/GBR complex formation links presynaptic GBR trafficking to Aβ formation. Our findings support that dysfunctional axonal trafficking and reduced GBR expression in Alzheimer's disease increases Aβ formation.
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Affiliation(s)
- Margarita C Dinamarca
- Department of Biomedicine, Institute of Physiology, University of Basel, Klingelbergstr. 50/70, 4056, Basel, Switzerland
| | - Adi Raveh
- Department of Biomedicine, Institute of Physiology, University of Basel, Klingelbergstr. 50/70, 4056, Basel, Switzerland
| | - Andy Schneider
- Faculty of Medicine, Institute of Physiology, University of Freiburg, Hermann-Herder-Str. 7, 79104, Freiburg, Germany
| | - Thorsten Fritzius
- Department of Biomedicine, Institute of Physiology, University of Basel, Klingelbergstr. 50/70, 4056, Basel, Switzerland
| | - Simon Früh
- Department of Biomedicine, Institute of Physiology, University of Basel, Klingelbergstr. 50/70, 4056, Basel, Switzerland
| | - Pascal D Rem
- Department of Biomedicine, Institute of Physiology, University of Basel, Klingelbergstr. 50/70, 4056, Basel, Switzerland
| | - Michal Stawarski
- Department of Biomedicine, Institute of Physiology, University of Basel, Klingelbergstr. 50/70, 4056, Basel, Switzerland
| | - Txomin Lalanne
- Department of Biomedicine, Institute of Physiology, University of Basel, Klingelbergstr. 50/70, 4056, Basel, Switzerland
| | - Rostislav Turecek
- Department of Biomedicine, Institute of Physiology, University of Basel, Klingelbergstr. 50/70, 4056, Basel, Switzerland
- Institute of Experimental Medicine, ASCR, Vı´denska´ 1083, 14220, Prague 4-Krc, Czech Republic
| | - Myeongjeong Choo
- Department of Biomedicine, Institute of Physiology, University of Basel, Klingelbergstr. 50/70, 4056, Basel, Switzerland
| | - Valérie Besseyrias
- Department of Biomedicine, Institute of Physiology, University of Basel, Klingelbergstr. 50/70, 4056, Basel, Switzerland
| | - Wolfgang Bildl
- Faculty of Medicine, Institute of Physiology, University of Freiburg, Hermann-Herder-Str. 7, 79104, Freiburg, Germany
| | - Detlef Bentrop
- Faculty of Medicine, Institute of Physiology, University of Freiburg, Hermann-Herder-Str. 7, 79104, Freiburg, Germany
| | - Matthias Staufenbiel
- Department of Cellular Neurology, Hertie Institute for Clinical Brain Research, University of Tübingen, Otfried-Müller-Strasse 27, 72076, Tübingen, Germany
| | - Martin Gassmann
- Department of Biomedicine, Institute of Physiology, University of Basel, Klingelbergstr. 50/70, 4056, Basel, Switzerland
| | - Bernd Fakler
- Faculty of Medicine, Institute of Physiology, University of Freiburg, Hermann-Herder-Str. 7, 79104, Freiburg, Germany
- Signalling Research Centers BIOSS and CIBSS, University of Freiburg, Schänzlestr. 18, 79104, Freiburg, Germany
| | - Jochen Schwenk
- Faculty of Medicine, Institute of Physiology, University of Freiburg, Hermann-Herder-Str. 7, 79104, Freiburg, Germany.
- Signalling Research Centers BIOSS and CIBSS, University of Freiburg, Schänzlestr. 18, 79104, Freiburg, Germany.
| | - Bernhard Bettler
- Department of Biomedicine, Institute of Physiology, University of Basel, Klingelbergstr. 50/70, 4056, Basel, Switzerland.
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