1
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Caracci MO, Pizarro H, Alarcón-Godoy C, Fuentealba LM, Farfán P, De Pace R, Santibañez N, Cavieres VA, Pástor TP, Bonifacino JS, Mardones GA, Marzolo MP. The Reelin receptor ApoER2 is a cargo for the adaptor protein complex AP-4: Implications for Hereditary Spastic Paraplegia. Prog Neurobiol 2024; 234:102575. [PMID: 38281682 PMCID: PMC10979513 DOI: 10.1016/j.pneurobio.2024.102575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 01/11/2024] [Accepted: 01/23/2024] [Indexed: 01/30/2024]
Abstract
Adaptor protein complex 4 (AP-4) is a heterotetrameric complex that promotes export of selected cargo proteins from the trans-Golgi network. Mutations in each of the AP-4 subunits cause a complicated form of Hereditary Spastic Paraplegia (HSP). Herein, we report that ApoER2, a receptor in the Reelin signaling pathway, is a cargo of the AP-4 complex. We identify the motif ISSF/Y within the ApoER2 cytosolic domain as necessary for interaction with the canonical signal-binding pocket of the µ4 (AP4M1) subunit of AP-4. AP4E1- knock-out (KO) HeLa cells and hippocampal neurons from Ap4e1-KO mice display increased co-localization of ApoER2 with Golgi markers. Furthermore, hippocampal neurons from Ap4e1-KO mice and AP4M1-KO human iPSC-derived cortical i3Neurons exhibit reduced ApoER2 protein expression. Analyses of biosynthetic transport of ApoER2 reveal differential post-Golgi trafficking of the receptor, with lower axonal distribution in KO compared to wild-type neurons, indicating a role of AP-4 and the ISSF/Y motif in the axonal localization of ApoER2. Finally, analyses of Reelin signaling in mouse hippocampal and human cortical KO neurons show that AP4 deficiency causes no changes in Reelin-dependent activation of the AKT pathway and only mild changes in Reelin-induced dendritic arborization, but reduces Reelin-induced ERK phosphorylation, CREB activation, and Golgi deployment. This work thus establishes ApoER2 as a novel cargo of the AP-4 complex, suggesting that defects in the trafficking of this receptor and in the Reelin signaling pathway could contribute to the pathogenesis of HSP caused by mutations in AP-4 subunits.
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Affiliation(s)
- Mario O Caracci
- Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, P. Universidad Católica de Chile, Santiago, Chile
| | - Héctor Pizarro
- Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, P. Universidad Católica de Chile, Santiago, Chile
| | - Carlos Alarcón-Godoy
- Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, P. Universidad Católica de Chile, Santiago, Chile
| | - Luz M Fuentealba
- Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, P. Universidad Católica de Chile, Santiago, Chile
| | - Pamela Farfán
- Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, P. Universidad Católica de Chile, Santiago, Chile
| | - Raffaella De Pace
- Neurosciences and Cellular and Structural Biology Division, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Natacha Santibañez
- Instituto de Patología Animal, Facultad de Ciencias Veterinarias, Universidad Austral de Chile, Valdivia, Chile
| | - Viviana A Cavieres
- Departamento de Ciencias Biológicas y Químicas, Fac. Med y Ciencia, USS, Santiago, Chile
| | - Tammy P Pástor
- Escuela de Medicina, Facultad de Medicina y Ciencia, Universidad San Sebastián, Valdivia, Chile
| | - Juan S Bonifacino
- Neurosciences and Cellular and Structural Biology Division, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Gonzalo A Mardones
- Escuela de Medicina, Facultad de Medicina y Ciencia, Universidad San Sebastián, Valdivia, Chile
| | - María-Paz Marzolo
- Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, P. Universidad Católica de Chile, Santiago, Chile.
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2
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Saffari A, Brechmann B, Böger C, Saber WA, Jumo H, Whye D, Wood D, Wahlster L, Alecu JE, Ziegler M, Scheffold M, Winden K, Hubbs J, Buttermore ED, Barrett L, Borner GHH, Davies AK, Ebrahimi-Fakhari D, Sahin M. High-content screening identifies a small molecule that restores AP-4-dependent protein trafficking in neuronal models of AP-4-associated hereditary spastic paraplegia. Nat Commun 2024; 15:584. [PMID: 38233389 PMCID: PMC10794252 DOI: 10.1038/s41467-023-44264-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 12/06/2023] [Indexed: 01/19/2024] Open
Abstract
Unbiased phenotypic screens in patient-relevant disease models offer the potential to detect therapeutic targets for rare diseases. In this study, we developed a high-throughput screening assay to identify molecules that correct aberrant protein trafficking in adapter protein complex 4 (AP-4) deficiency, a rare but prototypical form of childhood-onset hereditary spastic paraplegia characterized by mislocalization of the autophagy protein ATG9A. Using high-content microscopy and an automated image analysis pipeline, we screened a diversity library of 28,864 small molecules and identified a lead compound, BCH-HSP-C01, that restored ATG9A pathology in multiple disease models, including patient-derived fibroblasts and induced pluripotent stem cell-derived neurons. We used multiparametric orthogonal strategies and integrated transcriptomic and proteomic approaches to delineate potential mechanisms of action of BCH-HSP-C01. Our results define molecular regulators of intracellular ATG9A trafficking and characterize a lead compound for the treatment of AP-4 deficiency, providing important proof-of-concept data for future studies.
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Affiliation(s)
- Afshin Saffari
- Department of Neurology & F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
- Division of Child Neurology and Inherited Metabolic Diseases, Heidelberg University Hospital, Heidelberg, Germany
| | - Barbara Brechmann
- Department of Neurology & F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Cedric Böger
- Department of Neurology & F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Wardiya Afshar Saber
- Department of Neurology & F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Hellen Jumo
- Department of Neurology & F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
- Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Dosh Whye
- Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Delaney Wood
- Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Lara Wahlster
- Department of Hematology & Oncology, Boston Children's Hospital & Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, 02115, USA
| | - Julian E Alecu
- Department of Neurology & F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Marvin Ziegler
- Department of Neurology & F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Marlene Scheffold
- Department of Neurology & F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Kellen Winden
- Department of Neurology & F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Jed Hubbs
- Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Elizabeth D Buttermore
- Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Lee Barrett
- Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Georg H H Borner
- Department of Proteomics and Signal Transduction, Max-Planck-Institute of Biochemistry, Martinsried, 82152, Germany
| | - Alexandra K Davies
- Department of Proteomics and Signal Transduction, Max-Planck-Institute of Biochemistry, Martinsried, 82152, Germany
- School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, M13 9PT, UK
| | - Darius Ebrahimi-Fakhari
- Department of Neurology & F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA.
- Movement Disorders Program, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA.
| | - Mustafa Sahin
- Department of Neurology & F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
- Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
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3
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Caracci MO, Pizarro H, Alarcón-Godoy C, Fuentealba LM, Farfán P, Pace RD, Santibañez N, Cavieres VA, Pástor TP, Bonifacino JS, Mardones GA, Marzolo MP. The Reelin Receptor ApoER2 is a Cargo for the Adaptor Protein Complex AP-4: Implications for Hereditary Spastic Paraplegia. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.21.572896. [PMID: 38187774 PMCID: PMC10769347 DOI: 10.1101/2023.12.21.572896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
Adaptor protein complex 4 (AP-4) is a heterotetrameric complex that promotes protein export from the trans -Golgi network. Mutations in each of the AP-4 subunits cause a complicated form of Hereditary Spastic Paraplegia (HSP). Herein, we report that ApoER2, a receptor in the Reelin signaling pathway, is a cargo of the AP-4 complex. We identify the motif ISSF/Y within the ApoER2 cytosolic domain as necessary for interaction with the canonical signal-binding pocket of the µ4 (AP4M1) subunit of AP-4. AP4E1 -knock-out (KO) HeLa cells and hippocampal neurons from Ap4e1 -KO mice display increased Golgi localization of ApoER2. Furthermore, hippocampal neurons from Ap4e1 -KO mice and AP4M1 -KO human iPSC-derived cortical i3Neurons exhibit reduced ApoER2 protein expression. Analyses of biosynthetic transport of ApoER2 reveal differential post-Golgi trafficking of the receptor, with lower axonal distribution in KO compared to wild-type neurons, indicating a role of AP-4 and the ISSF/Y motif in the axonal localization of ApoER2. Finally, analyses of Reelin signaling in mouse hippocampal and human cortical KO neurons show that AP4 deficiency causes no changes in Reelin-dependent activation of the AKT pathway and only mild changes in Reelin-induced dendritic arborization, but reduces Reelin-induced ERK phosphorylation, CREB activation, and Golgi deployment. Altogether, this work establishes ApoER2 as a novel cargo of the AP-4 complex, suggesting that defects in the trafficking of this receptor and in the Reelin signaling pathway could contribute to the pathogenesis of HSP caused by mutations in AP-4 subunits.
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4
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Li Y, Zhang C, Peng G. Ap4s1 truncation leads to axonal defects in a zebrafish model of spastic paraplegia 52. Int J Dev Neurosci 2023; 83:753-764. [PMID: 37767851 DOI: 10.1002/jdn.10303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 08/11/2023] [Accepted: 09/08/2023] [Indexed: 09/29/2023] Open
Abstract
Biallelic mutations in AP4S1, the σ4 subunit of the adaptor protein complex 4 (AP-4), lead to autosomal recessive spastic paraplegia 52 (SPG52). It is a subtype of AP-4-associated hereditary spastic paraplegia (AP-4-HSP), a complex childhood-onset neurogenetic disease characterized by progressive spastic paraplegia of the lower limbs. This disease has so far lacked effective treatment, in part due to a lack of suitable animal models. Here, we used CRISPR/Cas9 technology to generate a truncation mutation in the ap4s1 gene in zebrafish. The ap4s1 truncation led to motor impairment, delayed neurodevelopment, and distal axonal degeneration. This animal model is useful for further research into AP-4 and AP-4-HSP.
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Affiliation(s)
- Yiduo Li
- State Key Laboratory of Medical Neurobiology, Ministry of Education Frontiers Center for Brain Science, and Institutes of Brain Science, Fudan University, Shanghai, China
| | - Cuizhen Zhang
- State Key Laboratory of Medical Neurobiology, Ministry of Education Frontiers Center for Brain Science, and Institutes of Brain Science, Fudan University, Shanghai, China
| | - Gang Peng
- State Key Laboratory of Medical Neurobiology, Ministry of Education Frontiers Center for Brain Science, and Institutes of Brain Science, Fudan University, Shanghai, China
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5
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Saffari A, Brechmann B, Boeger C, Saber WA, Jumo H, Whye D, Wood D, Wahlster L, Alecu J, Ziegler M, Scheffold M, Winden K, Hubbs J, Buttermore E, Barrett L, Borner G, Davies A, Sahin M, Ebrahimi-Fakhari D. High-Content Small Molecule Screen Identifies a Novel Compound That Restores AP-4-Dependent Protein Trafficking in Neuronal Models of AP-4-Associated Hereditary Spastic Paraplegia. RESEARCH SQUARE 2023:rs.3.rs-3036166. [PMID: 37398196 PMCID: PMC10312991 DOI: 10.21203/rs.3.rs-3036166/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Unbiased phenotypic screens in patient-relevant disease models offer the potential to detect novel therapeutic targets for rare diseases. In this study, we developed a high-throughput screening assay to identify molecules that correct aberrant protein trafficking in adaptor protein complex 4 (AP-4) deficiency, a rare but prototypical form of childhood-onset hereditary spastic paraplegia, characterized by mislocalization of the autophagy protein ATG9A. Using high-content microscopy and an automated image analysis pipeline, we screened a diversity library of 28,864 small molecules and identified a lead compound, C-01, that restored ATG9A pathology in multiple disease models, including patient-derived fibroblasts and induced pluripotent stem cell-derived neurons. We used multiparametric orthogonal strategies and integrated transcriptomic and proteomic approaches to delineate putative molecular targets of C-01 and potential mechanisms of action. Our results define molecular regulators of intracellular ATG9A trafficking and characterize a lead compound for the treatment of AP-4 deficiency, providing important proof-of-concept data for future Investigational New Drug (IND)-enabling studies.
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Affiliation(s)
| | | | | | | | | | - Dosh Whye
- Boston Children's Hospital, Harvard Medical School
| | - Delaney Wood
- Boston Children's Hospital, Harvard Medical School
| | | | - Julian Alecu
- Boston Children's Hospital, Harvard Medical School
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6
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Ebrahimi-Fakhari D, Alecu JE, Brechmann B, Ziegler M, Eberhardt K, Jumo H, D’Amore A, Habibzadeh P, Faghihi MA, De Bleecker JL, Vuillaumier-Barrot S, Auvin S, Santorelli FM, Neuser S, Popp B, Yang E, Barrett L, Davies AK, Saffari A, Hirst J, Sahin M. High-throughput imaging of ATG9A distribution as a diagnostic functional assay for adaptor protein complex 4-associated hereditary spastic paraplegia. Brain Commun 2021; 3:fcab221. [PMID: 34729478 PMCID: PMC8557665 DOI: 10.1093/braincomms/fcab221] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 08/05/2021] [Accepted: 08/19/2021] [Indexed: 01/09/2023] Open
Abstract
Adaptor protein complex 4-associated hereditary spastic paraplegia is caused by biallelic loss-of-function variants in AP4B1, AP4M1, AP4E1 or AP4S1, which constitute the four subunits of this obligate complex. While the diagnosis of adaptor protein complex 4-associated hereditary spastic paraplegia relies on molecular testing, the interpretation of novel missense variants remains challenging. Here, we address this diagnostic gap by using patient-derived fibroblasts to establish a functional assay that measures the subcellular localization of ATG9A, a transmembrane protein that is sorted by adaptor protein complex 4. Using automated high-throughput microscopy, we determine the ratio of the ATG9A fluorescence in the trans-Golgi-network versus cytoplasm and ascertain that this metric meets standards for screening assays (Z'-factor robust >0.3, strictly standardized mean difference >3). The 'ATG9A ratio' is increased in fibroblasts of 18 well-characterized adaptor protein complex 4-associated hereditary spastic paraplegia patients [mean: 1.54 ± 0.13 versus 1.21 ± 0.05 (standard deviation) in controls] and receiver-operating characteristic analysis demonstrates robust diagnostic power (area under the curve: 0.85, 95% confidence interval: 0.849-0.852). Using fibroblasts from two individuals with atypical clinical features and novel biallelic missense variants of unknown significance in AP4B1, we show that our assay can reliably detect adaptor protein complex 4 function. Our findings establish the 'ATG9A ratio' as a diagnostic marker of adaptor protein complex 4-associated hereditary spastic paraplegia.
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Affiliation(s)
- Darius Ebrahimi-Fakhari
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- The Manton Center for Orphan Disease Research, Boston Children’s Hospital, Boston, MA 02115, USA
| | - Julian E Alecu
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Barbara Brechmann
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- Division of Neuropediatrics and Inherited Metabolic Diseases, Center for Pediatrics and Adolescent Medicine, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Marvin Ziegler
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- Ruprecht-Karls University Heidelberg, Medical School, 69120 Heidelberg, Germany
| | - Kathrin Eberhardt
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Hellen Jumo
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Angelica D’Amore
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Parham Habibzadeh
- Persian BayanGene Research and Training Center, Shiraz University of Medical Sciences, 71347 Shiraz, Iran
| | - Mohammad Ali Faghihi
- Department of Psychiatry and Behavioral Sciences, University of Miami, Miami, FL 33136, USA
| | - Jan L De Bleecker
- Department of Neurology, Ghent University Hospital, 9000 Ghent, Belgium
| | | | - Stéphane Auvin
- Pediatric Neurology Department, AP-HP, Robert Debré Hospital, 75019 Paris, France
| | - Filippo M Santorelli
- Department of Molecular Medicine, IRCCS Fondazione Stella Maris, 56128 Pisa, Italy
| | - Sonja Neuser
- Institute of Human Genetics, University of Leipzig Medical Center, 04103 Leipzig, Germany
| | - Bernt Popp
- Institute of Human Genetics, University of Leipzig Medical Center, 04103 Leipzig, Germany
| | - Edward Yang
- Division of Neuroradiology, Department of Radiology, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Lee Barrett
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- Rosamund Stone Zander Translational Neuroscience Center, Boston Children’s Hospital, Boston, MA 02115, USA
| | - Alexandra K Davies
- Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Afshin Saffari
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- Division of Neuropediatrics and Inherited Metabolic Diseases, Center for Pediatrics and Adolescent Medicine, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Jennifer Hirst
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, UK
| | - Mustafa Sahin
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- Rosamund Stone Zander Translational Neuroscience Center, Boston Children’s Hospital, Boston, MA 02115, USA
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7
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Toupenet Marchesi L, Leblanc M, Stevanin G. Current Knowledge of Endolysosomal and Autophagy Defects in Hereditary Spastic Paraplegia. Cells 2021; 10:cells10071678. [PMID: 34359848 PMCID: PMC8307360 DOI: 10.3390/cells10071678] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 06/26/2021] [Accepted: 06/29/2021] [Indexed: 12/25/2022] Open
Abstract
Hereditary spastic paraplegia (HSP) refers to a group of neurological disorders involving the degeneration of motor neurons. Due to their clinical and genetic heterogeneity, finding common effective therapeutics is difficult. Therefore, a better understanding of the common pathological mechanisms is necessary. The role of several HSP genes/proteins is linked to the endolysosomal and autophagic pathways, suggesting a functional convergence. Furthermore, impairment of these pathways is particularly interesting since it has been linked to other neurodegenerative diseases, which would suggest that the nervous system is particularly sensitive to the disruption of the endolysosomal and autophagic systems. In this review, we will summarize the involvement of HSP proteins in the endolysosomal and autophagic pathways in order to clarify their functioning and decipher some of the pathological mechanisms leading to HSP.
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Affiliation(s)
- Liriopé Toupenet Marchesi
- Institut du Cerveau—Paris Brain Institute—ICM, INSERM, CNRS, APHP, Sorbonne Université, Pitié-Salpêtrière Hospital, 75013 Paris, France; (L.T.M.); (M.L.)
- Neurogenetics Team, EPHE, Paris Sciences Lettres Research University, 75000 Paris, France
| | - Marion Leblanc
- Institut du Cerveau—Paris Brain Institute—ICM, INSERM, CNRS, APHP, Sorbonne Université, Pitié-Salpêtrière Hospital, 75013 Paris, France; (L.T.M.); (M.L.)
- Neurogenetics Team, EPHE, Paris Sciences Lettres Research University, 75000 Paris, France
| | - Giovanni Stevanin
- Institut du Cerveau—Paris Brain Institute—ICM, INSERM, CNRS, APHP, Sorbonne Université, Pitié-Salpêtrière Hospital, 75013 Paris, France; (L.T.M.); (M.L.)
- Neurogenetics Team, EPHE, Paris Sciences Lettres Research University, 75000 Paris, France
- Correspondence:
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8
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Gadbery JE, Abraham A, Needle CD, Moth C, Sheehan J, Capra JA, Jackson LP. Integrating structural and evolutionary data to interpret variation and pathogenicity in adapter protein complex 4. Protein Sci 2020; 29:1535-1549. [PMID: 32285480 PMCID: PMC7255511 DOI: 10.1002/pro.3870] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 04/01/2020] [Accepted: 04/10/2020] [Indexed: 12/13/2022]
Abstract
Genetic variation in the membrane trafficking adapter protein complex 4 (AP-4) can result in pathogenic neurological phenotypes including microencephaly, spastic paraplegias, epilepsy, and other developmental defects. We lack molecular mechanisms responsible for impaired AP-4 function arising from genetic variation, because AP-4 remains poorly understood structurally. Here, we analyze patterns of AP-4 genetic evolution and conservation to identify regions that are likely important for function and thus more susceptible to pathogenic variation. We map known variants onto an AP-4 homology model and predict the likelihood of pathogenic variation at a given location on the structure of AP-4. We find significant clustering of likely pathogenic variants located at the interface between the β4 and N-μ4 subunits, as well as throughout the C-μ4 subunit. Our work offers an integrated perspective on how genetic and evolutionary forces affect AP-4 structure and function. As more individuals with uncharacterized AP-4 variants are identified, our work provides a foundation upon which their functional effects and disease relevance can be interpreted.
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Affiliation(s)
- John E. Gadbery
- Department of Biological SciencesVanderbilt UniversityNashvilleTennesseeUSA
| | - Abin Abraham
- Vanderbilt Genetics InstituteVanderbilt University School of MedicineNashvilleTennesseeUSA
| | - Carli D. Needle
- Department of Biological SciencesVanderbilt UniversityNashvilleTennesseeUSA
| | - Christopher Moth
- Center for Structural BiologyVanderbilt UniversityNashvilleTennesseeUSA
| | - Jonathan Sheehan
- Center for Structural BiologyVanderbilt UniversityNashvilleTennesseeUSA
- Department of BiochemistryVanderbilt University School of MedicineNashvilleTennesseeUSA
| | - John A. Capra
- Department of Biological SciencesVanderbilt UniversityNashvilleTennesseeUSA
- Vanderbilt Genetics InstituteVanderbilt University School of MedicineNashvilleTennesseeUSA
- Center for Structural BiologyVanderbilt UniversityNashvilleTennesseeUSA
- Department of Biomedical InformaticsVanderbilt University School of MedicineNashvilleTennesseeUSA
| | - Lauren P. Jackson
- Department of Biological SciencesVanderbilt UniversityNashvilleTennesseeUSA
- Center for Structural BiologyVanderbilt UniversityNashvilleTennesseeUSA
- Department of BiochemistryVanderbilt University School of MedicineNashvilleTennesseeUSA
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