DEPDC5 regulates the strength of excitatory synaptic transmission by interacting with ubiquitin-specific protease 46
DEP-domain containing-5 (DEPDC5) is part of the GATOR1 complex that inhibits the mechanistic target of rapamycin complex-1 (mTORC1). Loss-of-function mutations in human DEPDC5 are the most common cause of lesional or non-lesional focal epilepsies associated with mTOR hyperactivation. Depdc5 silencin...
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| Format: | Article |
| Language: | English |
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Elsevier
2025-08-01
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| Series: | Neurobiology of Disease |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S0969996125002013 |
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| author | Maria Sabina Cerullo Caterina Canevari Antonella Marte Alexandre Bacq Antonio De Fusco Marina Maletic Stéphanie Baulac Fabio Benfenati |
| author_facet | Maria Sabina Cerullo Caterina Canevari Antonella Marte Alexandre Bacq Antonio De Fusco Marina Maletic Stéphanie Baulac Fabio Benfenati |
| author_sort | Maria Sabina Cerullo |
| collection | DOAJ |
| description | DEP-domain containing-5 (DEPDC5) is part of the GATOR1 complex that inhibits the mechanistic target of rapamycin complex-1 (mTORC1). Loss-of-function mutations in human DEPDC5 are the most common cause of lesional or non-lesional focal epilepsies associated with mTOR hyperactivation. Depdc5 silencing in mature neurons leads to excitation/inhibition imbalance and increased excitatory synapse strength. However, no link exists between mTORC1 hyperactivity and the increased activity of glutamatergic synapses. Here, we found that genetic deletion of Depdc5 in a conditional knockout (cKO) mouse recapitulates the excitatory/inhibitory imbalance observed after transient Depdc5 silencing, with increased strength of excitatory transmission and unaffected inhibitory transmission. In Depdc5 cKO neurons, the increased glutamate quantal size and response to exogenous glutamate are attributable to a higher density of GluA1-containing AMPA glutamate receptors due to a shift of the GluA1 subunit from the intracellular pool to the plasma membrane. The DEPDC5 protein interaction network included WDR48, WDR20, and USP46, a ubiquitin-specific protease that regulates GluA1, as key binding partners, along with previously established components of the mTORC1 signaling pathway. In the absence of DEPDC5, USP46 levels increase, and ubiquitination of GluA1 decreases accordingly. Either knockdown of USP46 or rapamycin treatment rescues both the increased glutamate quantal size and USP46 increase caused by Depdc5 deletion, indicating that USP46 overexpression depends on mTORC1 hyperactivity. The data indicate that the DEPDC5/mTORC1 system physiologically controls the excitatory strength by negatively modulating USP46 activity and AMPA receptor deubiquitination, and that failure of this effect can contribute to the development of the Depdc5-linked epileptic phenotype. |
| format | Article |
| id | doaj-art-20cd4469aac74ccdb5158fe3213fd564 |
| institution | OA Journals |
| issn | 1095-953X |
| language | English |
| publishDate | 2025-08-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Neurobiology of Disease |
| spelling | doaj-art-20cd4469aac74ccdb5158fe3213fd5642025-08-20T02:35:44ZengElsevierNeurobiology of Disease1095-953X2025-08-0121210698510.1016/j.nbd.2025.106985DEPDC5 regulates the strength of excitatory synaptic transmission by interacting with ubiquitin-specific protease 46Maria Sabina Cerullo0Caterina Canevari1Antonella Marte2Alexandre Bacq3Antonio De Fusco4Marina Maletic5Stéphanie Baulac6Fabio Benfenati7Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Largo Rosanna Benzi 10, 16132 Genova, Italy; IRCCS Ospedale Policlinico San Martino, Largo Rosanna Benzi 10, 16132 Genova, ItalyCenter for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Largo Rosanna Benzi 10, 16132 Genova, Italy; Department of Experimental Medicine, University of Genova, Viale Benedetto XV 3, 16132 Genova, ItalyIRCCS Ospedale Policlinico San Martino, Largo Rosanna Benzi 10, 16132 Genova, Italy; Department of Experimental Medicine, University of Genova, Viale Benedetto XV 3, 16132 Genova, ItalyInstitut du Cerveau-Paris Brain Institute-ICM, Sorbonne Université, Inserm, CNRS, Hôpital de la Pitié Salpêtrière, F-75013 Paris, FranceCenter for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Largo Rosanna Benzi 10, 16132 Genova, ItalyInstitut du Cerveau-Paris Brain Institute-ICM, Sorbonne Université, Inserm, CNRS, Hôpital de la Pitié Salpêtrière, F-75013 Paris, FranceInstitut du Cerveau-Paris Brain Institute-ICM, Sorbonne Université, Inserm, CNRS, Hôpital de la Pitié Salpêtrière, F-75013 Paris, France; Corresponding author.Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Largo Rosanna Benzi 10, 16132 Genova, Italy; IRCCS Ospedale Policlinico San Martino, Largo Rosanna Benzi 10, 16132 Genova, Italy; Corresponding author at: Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Largo Rosanna Benzi 10, 16132 Genova, Italy.DEP-domain containing-5 (DEPDC5) is part of the GATOR1 complex that inhibits the mechanistic target of rapamycin complex-1 (mTORC1). Loss-of-function mutations in human DEPDC5 are the most common cause of lesional or non-lesional focal epilepsies associated with mTOR hyperactivation. Depdc5 silencing in mature neurons leads to excitation/inhibition imbalance and increased excitatory synapse strength. However, no link exists between mTORC1 hyperactivity and the increased activity of glutamatergic synapses. Here, we found that genetic deletion of Depdc5 in a conditional knockout (cKO) mouse recapitulates the excitatory/inhibitory imbalance observed after transient Depdc5 silencing, with increased strength of excitatory transmission and unaffected inhibitory transmission. In Depdc5 cKO neurons, the increased glutamate quantal size and response to exogenous glutamate are attributable to a higher density of GluA1-containing AMPA glutamate receptors due to a shift of the GluA1 subunit from the intracellular pool to the plasma membrane. The DEPDC5 protein interaction network included WDR48, WDR20, and USP46, a ubiquitin-specific protease that regulates GluA1, as key binding partners, along with previously established components of the mTORC1 signaling pathway. In the absence of DEPDC5, USP46 levels increase, and ubiquitination of GluA1 decreases accordingly. Either knockdown of USP46 or rapamycin treatment rescues both the increased glutamate quantal size and USP46 increase caused by Depdc5 deletion, indicating that USP46 overexpression depends on mTORC1 hyperactivity. The data indicate that the DEPDC5/mTORC1 system physiologically controls the excitatory strength by negatively modulating USP46 activity and AMPA receptor deubiquitination, and that failure of this effect can contribute to the development of the Depdc5-linked epileptic phenotype.http://www.sciencedirect.com/science/article/pii/S0969996125002013Depdc5 mutationsDEPDC5 interactomeAMPA receptorsDeubiquitinationExcitatory synaptic strengthPrimary neurons |
| spellingShingle | Maria Sabina Cerullo Caterina Canevari Antonella Marte Alexandre Bacq Antonio De Fusco Marina Maletic Stéphanie Baulac Fabio Benfenati DEPDC5 regulates the strength of excitatory synaptic transmission by interacting with ubiquitin-specific protease 46 Neurobiology of Disease Depdc5 mutations DEPDC5 interactome AMPA receptors Deubiquitination Excitatory synaptic strength Primary neurons |
| title | DEPDC5 regulates the strength of excitatory synaptic transmission by interacting with ubiquitin-specific protease 46 |
| title_full | DEPDC5 regulates the strength of excitatory synaptic transmission by interacting with ubiquitin-specific protease 46 |
| title_fullStr | DEPDC5 regulates the strength of excitatory synaptic transmission by interacting with ubiquitin-specific protease 46 |
| title_full_unstemmed | DEPDC5 regulates the strength of excitatory synaptic transmission by interacting with ubiquitin-specific protease 46 |
| title_short | DEPDC5 regulates the strength of excitatory synaptic transmission by interacting with ubiquitin-specific protease 46 |
| title_sort | depdc5 regulates the strength of excitatory synaptic transmission by interacting with ubiquitin specific protease 46 |
| topic | Depdc5 mutations DEPDC5 interactome AMPA receptors Deubiquitination Excitatory synaptic strength Primary neurons |
| url | http://www.sciencedirect.com/science/article/pii/S0969996125002013 |
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