1
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Yang P, Li W, Fan X, Pan J, Mann CJ, Varnum H, Clark LE, Clark SA, Coscia A, Basu H, Smith KN, Brusic V, Abraham J. Structural basis for VLDLR recognition by eastern equine encephalitis virus. Nat Commun 2024; 15:6548. [PMID: 39095394 PMCID: PMC11297306 DOI: 10.1038/s41467-024-50887-9] [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: 11/07/2023] [Accepted: 07/23/2024] [Indexed: 08/04/2024] Open
Abstract
Eastern equine encephalitis virus (EEEV) is the most virulent alphavirus that infects humans, and many survivors develop neurological sequelae, including paralysis and intellectual disability. Alphavirus spike proteins comprise trimers of heterodimers of glycoproteins E2 and E1 that mediate binding to cellular receptors and fusion of virus and host cell membranes during entry. We recently identified very-low density lipoprotein receptor (VLDLR) and apolipoprotein E receptor 2 (ApoER2) as cellular receptors for EEEV and a distantly related alphavirus, Semliki Forest virus (SFV). Here, we use single-particle cryo-electron microscopy (cryo-EM) to determine structures of the EEEV and SFV spike glycoproteins bound to the VLDLR ligand-binding domain and found that EEEV and SFV interact with the same cellular receptor through divergent binding modes. Our studies suggest that the ability of LDLR-related proteins to interact with viral spike proteins through very small footprints with flexible binding modes results in a low evolutionary barrier to the acquisition of LDLR-related proteins as cellular receptors for diverse sets of viruses.
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Affiliation(s)
- Pan Yang
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Wanyu Li
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Xiaoyi Fan
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Junhua Pan
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
- Biomedical Research Institute and School of Life and Health Sciences, Hubei University of Technology, Wuhan, Hubei, China
| | - Colin J Mann
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Haley Varnum
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Lars E Clark
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Sarah A Clark
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Adrian Coscia
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Himanish Basu
- Department of Immunology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Katherine Nabel Smith
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Vesna Brusic
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Jonathan Abraham
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA.
- Department of Medicine, Division of Infectious Diseases, Brigham & Women's Hospital, Boston, MA, USA.
- Center for Integrated Solutions in Infectious Diseases, Broad Institute of Harvard and MIT, Cambridge, MA, USA.
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2
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Holling T, Abdelrazek IM, Elhady GM, Abd Elmaksoud M, Ryu SW, Abdalla E, Kutsche K. A homozygous nonsense variant in the alternatively spliced VLDLR exon 4 causes a neurodevelopmental disorder without features of VLDLR cerebellar hypoplasia. J Hum Genet 2024:10.1038/s10038-024-01279-w. [PMID: 39085459 DOI: 10.1038/s10038-024-01279-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2024] [Revised: 07/17/2024] [Accepted: 07/20/2024] [Indexed: 08/02/2024]
Abstract
VLDLR cerebellar hypoplasia is characterized by intellectual disability, non-progressive cerebellar ataxia, and seizures. The characteristic MRI findings include hypoplasia of the inferior portion of the cerebellar vermis and hemispheres, simplified cortical gyration, and a small brain stem. Biallelic VLDLR pathogenic variants cause loss-of-function of the encoded very low-density lipoprotein receptor. VLDLR exons 4 and 16 are alternatively spliced, resulting in the expression of four transcript variants, including two exon 4-lacking mRNAs expressed in the human brain. Previously reported VLDLR pathogenic variants affect all four transcript variants. Here we report on two sisters with facial dysmorphism, microcephaly, intellectual disability, and normal brain imaging. Exome sequencing in one patient identified the homozygous VLDLR nonsense variant c.376C>T; p.(Gln126*) in exon 4; her similarly affected sister also carried the homozygous variant and parents were heterozygous carriers. VLDLR transcript analysis identified mRNAs with and without exon 4 in patient fibroblasts, while exon 4-containing VLDLR mRNAs were predominantly detected in control fibroblasts. We found significantly reduced VLDLR mRNA levels in patient compared to control cells, likely caused by nonsense-mediated mRNA decay of exon 4-containing VLDLR transcripts. Expression of neuronal VLDLR isoforms produced from exon 4-lacking transcripts may have protected both patients from developing the cerebellar hypoplasia phenotype.
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Affiliation(s)
- Tess Holling
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Ibrahim M Abdelrazek
- Department of Human Genetics, Medical Research Institute, Alexandria University, Alexandria, Egypt
| | - Ghada M Elhady
- Department of Human Genetics, Medical Research Institute, Alexandria University, Alexandria, Egypt
| | - Marwa Abd Elmaksoud
- Neurology Unit, Pediatric Department, Faculty of Medicine, Alexandria University, Alexandria, Egypt
| | | | - Ebtesam Abdalla
- Department of Human Genetics, Medical Research Institute, Alexandria University, Alexandria, Egypt
| | - Kerstin Kutsche
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
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3
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Markiewicz R, Markiewicz-Gospodarek A, Trubalski M, Łoza B. Neurocognitive, Clinical and Reelin Activity in Rehabilitation Using Neurofeedback Therapy in Patients with Schizophrenia. J Clin Med 2024; 13:4035. [PMID: 39064075 PMCID: PMC11277514 DOI: 10.3390/jcm13144035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2024] [Revised: 07/01/2024] [Accepted: 07/08/2024] [Indexed: 07/28/2024] Open
Abstract
Introduction: Reelin is a neuropeptide responsible for the migration and positioning of pyramidal neurons, interneurons, and Purkinje cells. In adulthood, it still supports neuroplasticity, especially dendritic spines formation and glutamatergic neurotransmission. Genetic studies have confirmed the involvement of reelin system failure in the etiopathogenesis of mental diseases, including schizophrenia. Given the role of reelin in brain cytoarchitectonics and the regularly observed reduction in its activity in prefrontal areas in cases of schizophrenia, dysfunction of the reelin pathway fits the neurodevelopmental hypothesis of schizophrenia, both as a biochemical predisposition and/or the ultimate trigger of psychosis and as a biosocial factor determining the clinical course, and finally, as a potential target for disease monitoring and treatment. Aim: The purpose of this study was to examine associations of the reelin blood level with clinical and neurocognitive parameters during an intensive, structured neurofeedback therapy of patients with schizophrenia. Methods: Thirty-seven male patients with paranoid schizophrenia were randomly divided into two groups: a group with 3-month neurofeedback as an add-on to ongoing antipsychotic treatment (NF, N18), and a control group with standard social support and antipsychotic treatment (CON, N19). The reelin serum concentration, clinical and neurocognitive tests were compared between the groups. Results: After 3-month trial (T2), the reelin serum level increased in the NF group vs. the CON group. The negative and general symptoms of PANSS (Positive and Negative Syndrome Scale) were reduced significantly more in the NF group at T2, and the d2 (d2 Sustained Attention Test) and BCIS (Beck Cognitive Insight Scale) scores improved only in the NF group. The AIS scores improved more dynamically in the NF group, but not enough to differentiate them from the CON group at T2. Conclusions: The clinical and neurocognitive improvement within the 3-month NF add-on therapy trial was associated with a significant increase of reelin serum level in schizophrenia patients.
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Affiliation(s)
- Renata Markiewicz
- Occupational Therapy Laboratory, Medical University of Lublin, 7 Chodźki St., 20-093 Lublin, Poland;
| | | | - Mateusz Trubalski
- Student Scientific Association at the Department of Normal, Clinical and Imaging Anatomy, Medical University of Lublin, 20-090 Lublin, Poland;
| | - Bartosz Łoza
- Department of Psychiatry, Medical University of Warsaw, 02-091 Warsaw, Poland;
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4
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Markiewicz R, Markiewicz-Gospodarek A, Borowski B, Trubalski M, Łoza B. Reelin Signaling and Synaptic Plasticity in Schizophrenia. Brain Sci 2023; 13:1704. [PMID: 38137152 PMCID: PMC10741648 DOI: 10.3390/brainsci13121704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 12/01/2023] [Accepted: 12/05/2023] [Indexed: 12/24/2023] Open
Abstract
Recent research emphasizes the significance of studying the quality of life of schizophrenia patients, considering the complex nature of the illness. Identifying neuronal markers for early diagnosis and treatment is crucial. Reelin (RELN) stands out among these markers, with genetic studies highlighting its role in mental health. Suppression of RELN expression may contribute to cognitive deficits by limiting dendritic proliferation, affecting neurogenesis, and leading to improper neuronal circuits. Although the physiological function of reelin is not fully understood, it plays a vital role in hippocampal cell stratification and neuroglia formation. This analysis explores reelin's importance in the nervous system, shedding light on its impact on mental disorders such as schizophrenia, paving the way for innovative therapeutic approaches, and at the same time, raises the following conclusions: increased methylation levels of the RELN gene in patients with a diagnosis of schizophrenia results in a multiple decrease in the expression of reelin, and monitoring of this indicator, i.e., methylation levels, can be used to monitor the severity of symptoms in the course of schizophrenia.
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Affiliation(s)
- Renata Markiewicz
- Occupational Therapy Laboratory, Chair of Nursing Development, Medical University of Lublin, 4 Staszica St., 20-081 Lublin, Poland;
| | | | - Bartosz Borowski
- Students Scientific Association, Department of Normal, Clinical and Imaging Anatomy, Medical University of Lublin, 20-090 Lublin, Poland; (B.B.); (M.T.)
| | - Mateusz Trubalski
- Students Scientific Association, Department of Normal, Clinical and Imaging Anatomy, Medical University of Lublin, 20-090 Lublin, Poland; (B.B.); (M.T.)
| | - Bartosz Łoza
- Department of Psychiatry, Medical University of Warsaw, 02-091 Warsaw, Poland;
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5
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Yang P, Li W, Fan X, Pan J, Mann CJ, Varnum H, Clark LE, Clark SA, Coscia A, Smith KN, Brusic V, Abraham J. Structural basis for VLDLR recognition by eastern equine encephalitis virus. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.14.567065. [PMID: 38014066 PMCID: PMC10680694 DOI: 10.1101/2023.11.14.567065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
Alphaviruses are arthropod-borne enveloped RNA viruses that include several important human pathogens with outbreak potential. Among them, eastern equine encephalitis virus (EEEV) is the most virulent, and many survivors develop neurological sequelae, including paralysis and intellectual disability. The spike proteins of alphaviruses comprise trimers of heterodimers of their envelope glycoproteins E2 and E1 that mediate binding to cellular receptors and fusion of virus and host cell membranes during entry. We recently identified very-low density lipoprotein receptor (VLDLR) and apolipoprotein E receptor 2 (ApoER2), two closely related proteins that are expressed in the brain, as cellular receptors for EEEV and a distantly related alphavirus, Semliki forest virus (SFV) 1 . The EEEV and SFV spike glycoproteins have low sequence homology, and how they have evolved to bind the same cellular receptors is unknown. Here, we used single-particle cryo-electron microscopy (cryo-EM) to determine structures of the EEEV and SFV spike glycoproteins bound to the VLDLR ligand-binding domain. The structures reveal that EEEV and SFV use distinct surfaces to bind VLDLR; EEEV uses a cluster of basic residues on the E2 subunit of its spike glycoprotein, while SFV uses two basic residues at a remote site on its E1 glycoprotein. Our studies reveal that different alphaviruses interact with the same cellular receptor through divergent binding modes. They further suggest that the ability of LDLR-related proteins to interact with viral spike proteins through very small footprints with flexible binding modes results in a low evolutionary barrier to the acquisition of LDLR-related proteins as cellular receptors for diverse sets of viruses.
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6
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Woods RM, Lorusso JM, Harris I, Kowash HM, Murgatroyd C, Neill JC, Glazier JD, Harte M, Hager R. Maternal Immune Activation Induces Adolescent Cognitive Deficits Preceded by Developmental Perturbations in Cortical Reelin Signalling. Biomolecules 2023; 13:biom13030489. [PMID: 36979424 PMCID: PMC10046789 DOI: 10.3390/biom13030489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 03/02/2023] [Accepted: 03/04/2023] [Indexed: 03/09/2023] Open
Abstract
Exposure to maternal immune activation (MIA) in utero significantly elevates the risk of developing schizophrenia and other neurodevelopmental disorders. To understand the biological mechanisms underlying the link between MIA and increased risk, preclinical animal models have focussed on specific signalling pathways in the brain that mediate symptoms associated with neurodevelopmental disorders such as cognitive dysfunction. Reelin signalling in multiple brain regions is involved in neuronal migration, synaptic plasticity and long-term potentiation, and has been implicated in cognitive deficits. However, how regulation of Reelin expression is affected by MIA across cortical development and associated cognitive functions remains largely unclear. Using a MIA rat model, here we demonstrate cognitive deficits in adolescent object-location memory in MIA offspring and reductions in Reln expression prenatally and in the adult prefrontal cortex. Further, developmental disturbances in gene/protein expression and DNA methylation of downstream signalling components occurred subsequent to MIA-induced Reelin dysregulation and prior to cognitive deficits. We propose that MIA-induced dysregulation of Reelin signalling contributes to the emergence of prefrontal cortex-mediated cognitive deficits through altered NMDA receptor function, resulting in inefficient long-term potentiation. Our data suggest a developmental window during which attenuation of Reelin signalling may provide a possible therapeutic target.
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Affiliation(s)
- Rebecca M. Woods
- Division of Evolution, Infection and Genomics, School of Biological Sciences, Manchester Academic Health Science Centre, Faculty of Biology, Medicine & Health, University of Manchester, Manchester M139PL, UK
- Correspondence: (R.M.W.); (J.M.L.)
| | - Jarred M. Lorusso
- Division of Evolution, Infection and Genomics, School of Biological Sciences, Manchester Academic Health Science Centre, Faculty of Biology, Medicine & Health, University of Manchester, Manchester M139PL, UK
- Correspondence: (R.M.W.); (J.M.L.)
| | - Isabella Harris
- Division of Evolution, Infection and Genomics, School of Biological Sciences, Manchester Academic Health Science Centre, Faculty of Biology, Medicine & Health, University of Manchester, Manchester M139PL, UK
| | - Hager M. Kowash
- Maternal and Fetal Health Research Centre, School of Medical Sciences, Manchester Academic Health Science Centre, Faculty of Biology, Medicine & Health, University of Manchester, Manchester M139PL, UK
| | | | - Joanna C. Neill
- Division of Pharmacy & Optometry, School of Health Sciences, Manchester Academic Health Science Centre, Faculty of Biology, Medicine & Health, University of Manchester, Manchester M139PL, UK
| | - Jocelyn D. Glazier
- Division of Evolution, Infection and Genomics, School of Biological Sciences, Manchester Academic Health Science Centre, Faculty of Biology, Medicine & Health, University of Manchester, Manchester M139PL, UK
| | - Michael Harte
- Division of Pharmacy & Optometry, School of Health Sciences, Manchester Academic Health Science Centre, Faculty of Biology, Medicine & Health, University of Manchester, Manchester M139PL, UK
| | - Reinmar Hager
- Division of Evolution, Infection and Genomics, School of Biological Sciences, Manchester Academic Health Science Centre, Faculty of Biology, Medicine & Health, University of Manchester, Manchester M139PL, UK
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7
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Pardo M, Gregorio S, Montalban E, Pujadas L, Elias-Tersa A, Masachs N, Vílchez-Acosta A, Parent A, Auladell C, Girault JA, Vila M, Nairn AC, Manso Y, Soriano E. Adult-specific Reelin expression alters striatal neuronal organization: implications for neuropsychiatric disorders. Front Cell Neurosci 2023; 17:1143319. [PMID: 37153634 PMCID: PMC10157100 DOI: 10.3389/fncel.2023.1143319] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Accepted: 03/27/2023] [Indexed: 05/10/2023] Open
Abstract
In addition to neuronal migration, brain development, and adult plasticity, the extracellular matrix protein Reelin has been extensively implicated in human psychiatric disorders such as schizophrenia, bipolar disorder, and autism spectrum disorder. Moreover, heterozygous reeler mice exhibit features reminiscent of these disorders, while overexpression of Reelin protects against its manifestation. However, how Reelin influences the structure and circuits of the striatal complex, a key region for the above-mentioned disorders, is far from being understood, especially when altered Reelin expression levels are found at adult stages. In the present study, we took advantage of complementary conditional gain- and loss-of-function mouse models to investigate how Reelin levels may modify adult brain striatal structure and neuronal composition. Using immunohistochemical techniques, we determined that Reelin does not seem to influence the striatal patch and matrix organization (studied by μ-opioid receptor immunohistochemistry) nor the density of medium spiny neurons (MSNs, studied with DARPP-32). We show that overexpression of Reelin leads to increased numbers of striatal parvalbumin- and cholinergic-interneurons, and to a slight increase in tyrosine hydroxylase-positive projections. We conclude that increased Reelin levels might modulate the numbers of striatal interneurons and the density of the nigrostriatal dopaminergic projections, suggesting that these changes may be involved in the protection of Reelin against neuropsychiatric disorders.
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Affiliation(s)
- Mònica Pardo
- Developmental Neurobiology and Regeneration Laboratory, Department of Cell Biology, Physiology and Immunology, Institute of Neurosciences, Universitat de Barcelona, Barcelona, Spain
- Centro de Investigación Biomédica en Red Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
| | - Sara Gregorio
- Developmental Neurobiology and Regeneration Laboratory, Department of Cell Biology, Physiology and Immunology, Institute of Neurosciences, Universitat de Barcelona, Barcelona, Spain
- Centro de Investigación Biomédica en Red Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
| | - Enrica Montalban
- Institut du Fer à Moulin UMR-S 1270, INSERM, Sorbonne University, Paris, France
| | - Lluís Pujadas
- Developmental Neurobiology and Regeneration Laboratory, Department of Cell Biology, Physiology and Immunology, Institute of Neurosciences, Universitat de Barcelona, Barcelona, Spain
- Centro de Investigación Biomédica en Red Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
- Department of Experimental Sciences and Methodology, Faculty of Health Science and Welfare, University of Vic – Central University of Catalonia (UVic-UCC), Vic, Spain
- Tissue Repair and Regeneration Laboratory (TR2Lab), Institut de Recerca i Innovació en Ciències de la Vida i de la Salut a la Catalunya Central (IRIS-CC), Barcelona, Spain
| | - Alba Elias-Tersa
- Developmental Neurobiology and Regeneration Laboratory, Department of Cell Biology, Physiology and Immunology, Institute of Neurosciences, Universitat de Barcelona, Barcelona, Spain
- Centro de Investigación Biomédica en Red Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
| | - Núria Masachs
- Developmental Neurobiology and Regeneration Laboratory, Department of Cell Biology, Physiology and Immunology, Institute of Neurosciences, Universitat de Barcelona, Barcelona, Spain
- Centro de Investigación Biomédica en Red Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
| | - Alba Vílchez-Acosta
- Developmental Neurobiology and Regeneration Laboratory, Department of Cell Biology, Physiology and Immunology, Institute of Neurosciences, Universitat de Barcelona, Barcelona, Spain
- Centro de Investigación Biomédica en Red Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
| | - Annabelle Parent
- Neurodegenerative Diseases Research Group, Vall d’Hebron Research Institute, Barcelona, Spain
| | - Carme Auladell
- Developmental Neurobiology and Regeneration Laboratory, Department of Cell Biology, Physiology and Immunology, Institute of Neurosciences, Universitat de Barcelona, Barcelona, Spain
- Centro de Investigación Biomédica en Red Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
| | | | - Miquel Vila
- Centro de Investigación Biomédica en Red Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
- Neurodegenerative Diseases Research Group, Vall d’Hebron Research Institute, Barcelona, Spain
- Department of Biochemistry and Molecular Biology, Autonomous University of Barcelona (UAB), Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD, United States
| | - Angus C. Nairn
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, United States
| | - Yasmina Manso
- Developmental Neurobiology and Regeneration Laboratory, Department of Cell Biology, Physiology and Immunology, Institute of Neurosciences, Universitat de Barcelona, Barcelona, Spain
- Centro de Investigación Biomédica en Red Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
- Yasmina Manso,
| | - Eduardo Soriano
- Developmental Neurobiology and Regeneration Laboratory, Department of Cell Biology, Physiology and Immunology, Institute of Neurosciences, Universitat de Barcelona, Barcelona, Spain
- Centro de Investigación Biomédica en Red Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
- *Correspondence: Eduardo Soriano,
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8
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Demir R, Deveci R. In silico analysis of glycosylation pattern in 5 th-6 th repeat sequence of reelin glycoprotein. J Biomol Struct Dyn 2022; 40:10065-10073. [PMID: 34121615 DOI: 10.1080/07391102.2021.1938682] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Reelin is an extracellular matrix glycoprotein that plays a key role in cortical development, maturation, synaptic plasticity, and memory formation in the adult mammalian brain. Glycosylation is a significant post- and co-translational modification of proteins. Although glycosylation contributes to the characteristic of proteins from their production to molecular interactions, the knowledge about the glycosylation pattern of reelin is very limited. In this study, we aimed to predict the potential glycosylation pattern of the 5th-6th repeat of central reelin fragment that responsible for their signaling, by using in silico methods. We found that the predicted glycosylation pattern of the 5th-6th repeat of human reelin was highly conserved between vertebrate species. However, this conservation was not observed in analyzed invertebrates. For the first time, we described the sites of glycosylation at a three-dimensional protein structure in human reelin. Because the sites were very closed to EGF-like repeats and receptor binding sites, they could contribute the interaction with a partner of reelin in addition to the effect of thermostability to protein. Many of the residues related glycosylation were also conserved in analyzed species. These findings may guide biochemical, genetic, and glycobiology base on further experiments about reelin glycosylation. The understanding of reelin glycosylation might change the point of view of treatment for many pathological conditions in neurodegenerative diseases such as Alzheimer's disease. Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Ramiz Demir
- Faculty of Science, Department of Biology, Molecular Biology Section, Ege University, Izmir, Turkey.,The Graduate School of Health Sciences, Koç University Research Center for Translational Medicine (KUTTAM), Koç University, Istanbul, Turkey
| | - Remziye Deveci
- Faculty of Science, Department of Biology, Molecular Biology Section, Ege University, Izmir, Turkey
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9
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Chun H, Kurasawa JH, Olivares P, Marakasova ES, Shestopal SA, Hassink GU, Karnaukhova E, Migliorini M, Obi JO, Smith AK, Wintrode PL, Durai P, Park K, Deredge D, Strickland DK, Sarafanov AG. Characterization of interaction between blood coagulation factor VIII and LRP1 suggests dynamic binding by alternating complex contacts. J Thromb Haemost 2022; 20:2255-2269. [PMID: 35810466 PMCID: PMC9804390 DOI: 10.1111/jth.15817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 06/15/2022] [Accepted: 07/01/2022] [Indexed: 01/07/2023]
Abstract
BACKGROUND Deficiency in blood coagulation factor VIII (FVIII) results in life-threating bleeding (hemophilia A) treated by infusions of FVIII concentrates. To improve disease treatment, FVIII has been modified to increase its plasma half-life, which requires understanding mechanisms of FVIII catabolism. An important catabolic actor is hepatic low density lipoprotein receptor-related protein 1 (LRP1), which also regulates many other clinically significant processes. Previous studies showed complexity of FVIII site for binding LRP1. OBJECTIVES To characterize binding sites between FVIII and LRP1 and suggest a model of the interaction. METHODS A series of recombinant ligand-binding complement-type repeat (CR) fragments of LRP1 including mutated variants was generated in a baculovirus system and tested for FVIII interaction using surface plasmon resonance, tissue culture model, hydrogen-deuterium exchange mass spectrometry, and in silico. RESULTS Multiple CR doublets within LRP1 clusters II and IV were identified as alternative FVIII-binding sites. These interactions follow the canonical binding mode providing major binding energy, and additional weak interactions are contributed by adjacent CR domains. A representative CR doublet was shown to have multiple contact sites on FVIII. CONCLUSIONS FVIII and LRP1 interact via formation of multiple complex contacts involving both canonical and non-canonical binding combinations. We propose that FVIII-LRP1 interaction occurs via switching such alternative binding combinations in a dynamic mode, and that this mechanism is relevant to other ligand interactions of the low-density lipoprotein receptor family members including LRP1.
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Affiliation(s)
- Haarin Chun
- Center for Biologics Evaluation and ResearchU.S. Food and Drug AdministrationSilver SpringMarylandUSA
| | - James H. Kurasawa
- Center for Biologics Evaluation and ResearchU.S. Food and Drug AdministrationSilver SpringMarylandUSA
- Present address:
Biologics Engineering, R&D, AstraZeneca, GaithersburgMarylandUSA
| | - Philip Olivares
- Center for Biologics Evaluation and ResearchU.S. Food and Drug AdministrationSilver SpringMarylandUSA
| | - Ekaterina S. Marakasova
- Center for Biologics Evaluation and ResearchU.S. Food and Drug AdministrationSilver SpringMarylandUSA
- Present address:
(1) Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver SpringMarylandUSA
- Present address:
George Mason University, School of Systems Biology, FairfaxVirginiaUSA
| | - Svetlana A. Shestopal
- Center for Biologics Evaluation and ResearchU.S. Food and Drug AdministrationSilver SpringMarylandUSA
| | - Gabriela U. Hassink
- Center for Biologics Evaluation and ResearchU.S. Food and Drug AdministrationSilver SpringMarylandUSA
- Present address:
GSK‐Rockville Center for Vaccines Research, RockvilleMarylandUSA
| | - Elena Karnaukhova
- Center for Biologics Evaluation and ResearchU.S. Food and Drug AdministrationSilver SpringMarylandUSA
| | - Mary Migliorini
- Center for Vascular and Inflammatory DiseasesDepartments of Surgery and PhysiologyUniversity of Maryland School of MedicineBaltimoreMarylandUSA
| | - Juliet O. Obi
- Department of Pharmaceutical SciencesUniversity of Maryland School of PharmacyBaltimoreMarylandUSA
| | - Ally K. Smith
- Department of Pharmaceutical SciencesUniversity of Maryland School of PharmacyBaltimoreMarylandUSA
| | - Patrick L. Wintrode
- Department of Pharmaceutical SciencesUniversity of Maryland School of PharmacyBaltimoreMarylandUSA
| | - Prasannavenkatesh Durai
- Natural Product Informatics Research CenterKorea Institute of Science and TechnologyGangneungRepublic of Korea
| | - Keunwan Park
- Natural Product Informatics Research CenterKorea Institute of Science and TechnologyGangneungRepublic of Korea
| | - Daniel Deredge
- Department of Pharmaceutical SciencesUniversity of Maryland School of PharmacyBaltimoreMarylandUSA
| | - Dudley K. Strickland
- Center for Vascular and Inflammatory DiseasesDepartments of Surgery and PhysiologyUniversity of Maryland School of MedicineBaltimoreMarylandUSA
| | - Andrey G. Sarafanov
- Center for Biologics Evaluation and ResearchU.S. Food and Drug AdministrationSilver SpringMarylandUSA
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Lipophorin receptors regulate mushroom body development and complex behaviors in Drosophila. BMC Biol 2022; 20:198. [PMID: 36071487 PMCID: PMC9454125 DOI: 10.1186/s12915-022-01393-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 08/17/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Drosophila melanogaster lipophorin receptors (LpRs), LpR1 and LpR2, are members of the LDLR family known to mediate lipid uptake in a range of organisms from Drosophila to humans. The vertebrate orthologs of LpRs, ApoER2 and VLDL-R, function as receptors of a glycoprotein involved in development of the central nervous system, Reelin, which is not present in flies. ApoER2 and VLDL-R are associated with the development and function of the hippocampus and cerebral cortex, important association areas in the mammalian brain, as well as with neurodevelopmental and neurodegenerative disorders linked to those regions. It is currently unknown whether LpRs play similar roles in the Drosophila brain. RESULTS We report that LpR-deficient flies exhibit impaired olfactory memory and sleep patterns, which seem to reflect anatomical defects found in a critical brain association area, the mushroom bodies (MB). Moreover, cultured MB neurons respond to mammalian Reelin by increasing the complexity of their neurite arborization. This effect depends on LpRs and Dab, the Drosophila ortholog of the Reelin signaling adaptor protein Dab1. In vitro, two of the long isoforms of LpRs allow the internalization of Reelin, suggesting that Drosophila LpRs interact with human Reelin to induce downstream cellular events. CONCLUSIONS These findings demonstrate that LpRs contribute to MB development and function, supporting the existence of a LpR-dependent signaling in Drosophila, and advance our understanding of the molecular factors functioning in neural systems to generate complex behaviors in this model. Our results further emphasize the importance of Drosophila as a model to investigate the alterations in specific genes contributing to neural disorders.
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11
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Structure of Reelin repeat 8 and the adjacent C-terminal region. Biophys J 2022; 121:2526-2537. [DOI: 10.1016/j.bpj.2022.06.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 05/15/2022] [Accepted: 05/31/2022] [Indexed: 11/02/2022] Open
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12
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Omuro KC, Gallo CM, Scrandis L, Ho A, Beffert U. Human APOER2 Isoforms Have Differential Cleavage Events and Synaptic Properties. J Neurosci 2022; 42:4054-4068. [PMID: 35414534 PMCID: PMC9121830 DOI: 10.1523/jneurosci.1800-21.2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 03/24/2022] [Accepted: 04/06/2022] [Indexed: 11/21/2022] Open
Abstract
Human apolipoprotein E receptor 2 (APOER2) is a type I transmembrane protein with a large extracellular domain (ECD) and a short cytoplasmic tail. APOER2-ECD contains several ligand-binding domains (LBDs) that are organized into exons with aligning phase junctions, which allows for in-frame exon cassette splicing events. We have identified 25 human APOER2 isoforms from cerebral cortex using gene-specific APOER2 primers, where the majority are exon-skipping events within the N-terminal LBD regions compared with six identified in the heart. APOER2 undergoes proteolytic cleavage in response to ligand binding that releases a C-terminal fragment (CTF) and transcriptionally active intracellular domain (ICD). We tested whether the diversity of human brain-specific APOER2 variants affects APOER2 cleavage. We found isoforms with differing numbers of ligand-binding repeats generated different amounts of CTFs compared with full-length APOER2 (APOER2-FL). Specifically, APOER2 isoforms lacking exons 5-8 (Δex5-8) and lacking exons 4-6 (Δex4-6) generated the highest and lowest amounts of CTF generation, respectively, in response to APOE peptide compared with APOER2-FL. The differential CTF generation of Δex5-8 and Δex4-6 coincides with the proteolytic release of the ICD, which mediates transcriptional activation facilitated by the Mint1 adaptor protein. Functionally, we demonstrated loss of mouse Apoer2 decreased miniature event frequency in excitatory synapses, which may be because of a decrease in the total number of synapses and/or VAMP2 positive neurons. Lentiviral infection with human APOER2-FL or Δex4-6 isoform in Apoer2 knockout neurons restored the miniature event frequency but not Δex5-8 isoform. These results suggest that human APOER2 isoforms have differential cleavage events and synaptic properties.SIGNIFICANCE STATEMENT Humans and mice share virtually the same number of protein-coding genes. However, humans have greater complexity of any higher eukaryotic organisms by encoding multiple protein forms through alternative splicing modifications. Alternative splicing allows pre-mRNAs transcribed from genes to be spliced in different arrangements, producing structurally and functionally distinct protein variants that increase proteomic diversity and are particularly prevalent in the human brain. Here, we identified 25 distinct human APOER2 splice variants from the cerebral cortex using gene-specific APOER2 primers, where the majority are exon-skipping events that exclude N-terminal ligand-binding regions of APOER2. We show that some of the APOER2 variants have differential proteolytic properties in response to APOE ligand and exhibit distinct synaptic properties.
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Affiliation(s)
| | | | - Lauren Scrandis
- Department of Biology, Boston University, Boston, Massachusetts 02215
| | - Angela Ho
- Department of Biology, Boston University, Boston, Massachusetts 02215
| | - Uwe Beffert
- Department of Biology, Boston University, Boston, Massachusetts 02215
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13
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Ramsden CE, Keyes GS, Calzada E, Horowitz MS, Zamora D, Jahanipour J, Sedlock A, Indig FE, Moaddel R, Kapogiannis D, Maric D. Lipid Peroxidation Induced ApoE Receptor-Ligand Disruption as a Unifying Hypothesis Underlying Sporadic Alzheimer's Disease in Humans. J Alzheimers Dis 2022; 87:1251-1290. [PMID: 35466940 DOI: 10.3233/jad-220071] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
BACKGROUND Sporadic Alzheimer's disease (sAD) lacks a unifying hypothesis that can account for the lipid peroxidation observed early in the disease, enrichment of ApoE in the core of neuritic plaques, hallmark plaques and tangles, and selective vulnerability of entorhinal-hippocampal structures. OBJECTIVE We hypothesized that 1) high expression of ApoER2 (receptor for ApoE and Reelin) helps explain this anatomical vulnerability; 2) lipid peroxidation of ApoE and ApoER2 contributes to sAD pathogenesis, by disrupting neuronal ApoE delivery and Reelin-ApoER2-Dab1 signaling cascades. METHODS In vitro biochemical experiments; Single-marker and multiplex fluorescence-immunohistochemistry (IHC) in postmortem specimens from 26 individuals who died cognitively normal, with mild cognitive impairment or with sAD. RESULTS ApoE and ApoER2 peptides and proteins were susceptible to attack by reactive lipid aldehydes, generating lipid-protein adducts and crosslinked ApoE-ApoER2 complexes. Using in situ hybridization alongside IHC, we observed that: 1) ApoER2 is strongly expressed in terminal zones of the entorhinal-hippocampal 'perforant path' projections that underlie memory; 2) ApoE, lipid aldehyde-modified ApoE, Reelin, ApoER2, and the downstream Reelin-ApoER2 cascade components Dab1 and Thr19-phosphorylated PSD95 accumulated in the vicinity of neuritic plaques in perforant path terminal zones in sAD cases; 3) several ApoE/Reelin-ApoER2-Dab1 pathway markers were higher in sAD cases and positively correlated with histological progression and cognitive deficits. CONCLUSION Results demonstrate derangements in multiple ApoE/Reelin-ApoER2-Dab1 axis components in perforant path terminal zones in sAD and provide proof-of-concept that ApoE and ApoER2 are vulnerable to aldehyde-induced adduction and crosslinking. Findings provide the foundation for a unifying hypothesis implicating lipid peroxidation of ApoE and ApoE receptors in sAD.
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Affiliation(s)
- Christopher E Ramsden
- Lipid Peroxidation Unit, Laboratory of Clinical Investigation, National Institute on Aging, NIH, Baltimore, MD, USA.,Intramural Program of the National Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, MD, USA
| | - Gregory S Keyes
- Lipid Peroxidation Unit, Laboratory of Clinical Investigation, National Institute on Aging, NIH, Baltimore, MD, USA
| | - Elizabeth Calzada
- Lipid Peroxidation Unit, Laboratory of Clinical Investigation, National Institute on Aging, NIH, Baltimore, MD, USA
| | - Mark S Horowitz
- Lipid Peroxidation Unit, Laboratory of Clinical Investigation, National Institute on Aging, NIH, Baltimore, MD, USA
| | - Daisy Zamora
- Lipid Peroxidation Unit, Laboratory of Clinical Investigation, National Institute on Aging, NIH, Baltimore, MD, USA
| | - Jahandar Jahanipour
- Flow and Imaging Cytometry Core Facility, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD, USA
| | - Andrea Sedlock
- Flow and Imaging Cytometry Core Facility, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD, USA
| | - Fred E Indig
- Confocal Imaging Facility, National Institute on Aging Intramural Research Program, NIH, Baltimore, MD, USA
| | - Ruin Moaddel
- Laboratory of Clinical Investigation, National Institute on Aging, NIH, Baltimore, MD, USA
| | - Dimitrios Kapogiannis
- Human Neuroscience Unit, Laboratory of Clinical Investigation, National Institute on Aging, NIH, Baltimore, MD, USA
| | - Dragan Maric
- Flow and Imaging Cytometry Core Facility, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD, USA
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14
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Meijer DH, Frias CP, Beugelink JW, Deurloo YN, Janssen BJC. Teneurin4 dimer structures reveal a calcium‐stabilized compact conformation supporting homomeric trans‐interactions. EMBO J 2022; 41:e107505. [PMID: 35099835 PMCID: PMC9058538 DOI: 10.15252/embj.2020107505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 12/20/2021] [Accepted: 12/22/2021] [Indexed: 11/18/2022] Open
Abstract
Establishment of correct synaptic connections is a crucial step during neural circuitry formation. The Teneurin family of neuronal transmembrane proteins promotes cell–cell adhesion via homophilic and heterophilic interactions, and is required for synaptic partner matching in the visual and hippocampal systems in vertebrates. It remains unclear how individual Teneurins form macromolecular cis‐ and trans‐synaptic protein complexes. Here, we present a 2.7 Å cryo‐EM structure of the dimeric ectodomain of human Teneurin4. The structure reveals a compact conformation of the dimer, stabilized by interactions mediated by the C‐rich, YD‐shell, and ABD domains. A 1.5 Å crystal structure of the C‐rich domain shows three conserved calcium binding sites, and thermal unfolding assays and SAXS‐based rigid‐body modeling demonstrate that the compactness and stability of Teneurin4 dimers are calcium‐dependent. Teneurin4 dimers form a more extended conformation in conditions that lack calcium. Cellular assays reveal that the compact cis‐dimer is compatible with homomeric trans‐interactions. Together, these findings support a role for teneurins as a scaffold for macromolecular complex assembly and the establishment of cis‐ and trans‐synaptic interactions to construct functional neuronal circuits.
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Affiliation(s)
- Dimphna H Meijer
- Department of Bionanoscience Kavli Institute of Nanoscience Delft University of Technology Delft The Netherlands
- Department of Chemistry Faculty of Science Structural Biochemistry Bijvoet Center for Biomolecular Research Utrecht University Utrecht The Netherlands
| | - Cátia P Frias
- Department of Bionanoscience Kavli Institute of Nanoscience Delft University of Technology Delft The Netherlands
| | - J Wouter Beugelink
- Department of Chemistry Faculty of Science Structural Biochemistry Bijvoet Center for Biomolecular Research Utrecht University Utrecht The Netherlands
| | - Yanthi N Deurloo
- Department of Bionanoscience Kavli Institute of Nanoscience Delft University of Technology Delft The Netherlands
| | - Bert J C Janssen
- Department of Chemistry Faculty of Science Structural Biochemistry Bijvoet Center for Biomolecular Research Utrecht University Utrecht The Netherlands
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15
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Nagae M, Suzuki K, Yasui N, Nogi T, Kohno T, Hattori M, Takagi J. Structural studies of reelin N-terminal region provides insights into a unique structural arrangement and functional multimerization. J Biochem 2021; 169:555-564. [PMID: 33377147 DOI: 10.1093/jb/mvaa144] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 12/03/2020] [Indexed: 01/31/2023] Open
Abstract
The large, secreted glycoprotein reelin regulates embryonic brain development as well as adult brain functions. Although reelin binds to its receptors via its central part, the N-terminal region directs multimer formation and is critical for efficient signal transduction. In fact, the inhibitory antibody CR-50 interacts with the N-terminal region and prevents higher-order multimerization and signalling. Reelin is a multidomain protein in which the central part is composed of eight characteristic repeats, named reelin repeats, each of which is further divided by insertion of a epidermal growth factor (EGF) module into two subrepeats. In contrast, the N-terminal region shows unique 'irregular' domain architecture since it comprises three consecutive subrepeats without the intervening EGF module. Here, we determined the crystal structure of the murine reelin fragment named RX-R1 including the irregular region and the first reelin repeat at 2.0-Å resolution. The overall structure of RX-R1 has a branched Y-shaped form. Interestingly, two incomplete subrepeats cooperatively form one entire subrepeat structure, though an additional subrepeat is inserted between them. We further reveal that Arg335 of RX-R1 is crucial for binding CR-50. A possible self-association mechanism via the N-terminal region is proposed based on our results.
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Affiliation(s)
- Masamichi Nagae
- Department of Molecular Immunology, Research Institute for Microbial Diseases.,Laboratory of Molecular Immunology, Immunology Frontier Research Center (iFReC), Osaka University, 3-1 Yamada-Oka, Suita, Osaka 565-0871, Japan
| | - Kei Suzuki
- Institute for Protein Research, Osaka University, 3-2 Yamada-Oka, Suita, Osaka 565-0871, Japan
| | - Norihisa Yasui
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 1-1-1, Tsushima-naka, Kita-ku, Okayama 700-8530, Japan
| | - Terukazu Nogi
- Graduate School of Medical Life Science, Yokohama City University, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Takao Kohno
- Department of Biomedical Science, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Aichi 467-8603, Japan
| | - Mitsuharu Hattori
- Department of Biomedical Science, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Aichi 467-8603, Japan
| | - Junichi Takagi
- Institute for Protein Research, Osaka University, 3-2 Yamada-Oka, Suita, Osaka 565-0871, Japan
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16
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Veenstra JA. Ambulacrarian insulin-related peptides and their putative receptors suggest how insulin and similar peptides may have evolved from insulin-like growth factor. PeerJ 2021; 9:e11799. [PMID: 34316411 PMCID: PMC8286064 DOI: 10.7717/peerj.11799] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 06/25/2021] [Indexed: 01/23/2023] Open
Abstract
Background Some insulin/IGF-related peptides (irps) stimulate a receptor tyrosine kinase (RTK) that transfers the extracellular hormonal signal into an intracellular response. Other irps, such as relaxin, do not use an RTK, but a G-protein coupled receptor (GPCR). This is unusual since evolutionarily related hormones typically either use the same or paralogous receptors. In arthropods three different irps, i.e. arthropod IGF, gonadulin and Drosophila insulin-like peptide 7 (dilp7), likely evolved from a gene triplication, as in several species genes encoding these three peptides are located next to one another on the same chromosomal fragment. These arthropod irps have homologs in vertebrates, suggesting that the initial gene triplication was perhaps already present in the last common ancestor of deuterostomes and protostomes. It would be interesting to know whether this is indeed so and how insulin might be related to this trio of irps. Methodology Genes encoding irps as well as their putative receptors were identified in genomes and transcriptomes from echinoderms and hemichordates. Results A similar triplet of genes coding for irps also occurs in some ambulacrarians. Two of these are orthologs of arthropod IGF and dilp7 and the third is likely a gonadulin ortholog. In echinoderms, two novel irps emerged, gonad stimulating substance (GSS) and multinsulin, likely from gene duplications of the IGF and dilp7-like genes respectively. The structures of GSS diverged considerably from IGF, which would suggest they use different receptors from IGF, but no novel irp receptors evolved. If IGF and GSS use different receptors, and the evolution of GSS from a gene duplication of IGF is not associated with the appearance of a novel receptor, while irps are known to use two different types of receptors, the ancestor of GSS and IGF might have acted on both types of receptors while one or both of its descendants act on only one. There are three ambulacrarian GPCRs that have amino acid sequences suggestive of being irp GPCRs, two of these are orthologs of the gonadulin and dilp7 receptors. This suggests that the third might be an IGF receptor, and that by deduction, GSS only acts on the RTK. The evolution of GSS from IGF may represent a pattern, where IGF gene duplications lead to novel genes coding for shorter peptides that activate an RTK. It is likely this is how insulin and the insect neuroendocrine irps evolved independently from IGF. Conclusion The local gene triplication described from arthropods that yielded three genes encoding irps was already present in the last common ancestor of protostomes and deuterostomes. It seems plausible that irps, such as those produced by neuroendocrine cells in the brain of insects and echinoderm GSS evolved independently from IGF and, thus, are not true orthologs, but the result of convergent evolution.
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Affiliation(s)
- Jan A Veenstra
- INCIA UMR 5287 CNRS, Université de Bordeaux, Pessac, Gironde, France
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17
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Turk LS, Kuang X, Dal Pozzo V, Patel K, Chen M, Huynh K, Currie MJ, Mitchell D, Dobson RCJ, D'Arcangelo G, Dai W, Comoletti D. The structure-function relationship of a signaling-competent, dimeric Reelin fragment. Structure 2021; 29:1156-1170.e6. [PMID: 34089653 DOI: 10.1016/j.str.2021.05.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 04/26/2021] [Accepted: 05/14/2021] [Indexed: 01/21/2023]
Abstract
Reelin operates through canonical and non-canonical pathways that mediate several aspects of brain development and function. Reelin's dimeric central fragment (CF), generated through proteolytic cleavage, is required for the lipoprotein-receptor-dependent canonical pathway activation. Here, we analyze the signaling properties of a variety of Reelin fragments and measure the differential binding affinities of monomeric and dimeric CF fragments to lipoprotein receptors to investigate the mode of canonical signal activation. We also present the cryoelectron tomography-solved dimeric structure of Reelin CF and support it using several other biophysical techniques. Our findings suggest that Reelin CF forms a covalent parallel dimer with some degree of flexibility between the two protein chains. As a result of this conformation, Reelin binds to lipoprotein receptors in a manner inaccessible to its monomeric form and is capable of stimulating canonical pathway signaling.
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Affiliation(s)
- Liam S Turk
- Child Health Institute of New Jersey, New Brunswick, NJ 08901, USA; Department of Neuroscience and Cell Biology, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901, USA; School of Biological Sciences, Victoria University of Wellington, Wellington 6012, New Zealand
| | - Xuyuan Kuang
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA; Institute for Quantitative Biomedicine, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA; Department of Hyperbaric Oxygen, Central South University, Changsha, Hunan Province, China
| | - Valentina Dal Pozzo
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Khush Patel
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Muyuan Chen
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Kevin Huynh
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA; Institute for Quantitative Biomedicine, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Michael J Currie
- Biomolecular Interactions Centre and School of Biological Sciences, University of Canterbury, Christchurch 8041, New Zealand
| | - Daniel Mitchell
- School of Biological Sciences, Victoria University of Wellington, Wellington 6012, New Zealand
| | - Renwick C J Dobson
- Biomolecular Interactions Centre and School of Biological Sciences, University of Canterbury, Christchurch 8041, New Zealand; Bio21 Molecular Science and Biotechnology Institute, Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, VIC 3010, Australia
| | - Gabriella D'Arcangelo
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Wei Dai
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA; Institute for Quantitative Biomedicine, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA.
| | - Davide Comoletti
- Child Health Institute of New Jersey, New Brunswick, NJ 08901, USA; Department of Neuroscience and Cell Biology, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901, USA; School of Biological Sciences, Victoria University of Wellington, Wellington 6012, New Zealand.
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18
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Marakasova E, Olivares P, Karnaukhova E, Chun H, Hernandez NE, Kurasawa JH, Hassink GU, Shestopal SA, Strickland DK, Sarafanov AG. Molecular chaperone RAP interacts with LRP1 in a dynamic bivalent mode and enhances folding of ligand-binding regions of other LDLR family receptors. J Biol Chem 2021; 297:100842. [PMID: 34058195 PMCID: PMC8239462 DOI: 10.1016/j.jbc.2021.100842] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Revised: 05/20/2021] [Accepted: 05/26/2021] [Indexed: 11/16/2022] Open
Abstract
The low-density lipoprotein receptor (LDLR) family of receptors are cell-surface receptors that internalize numerous ligands and play crucial role in various processes, such as lipoprotein metabolism, hemostasis, fetal development, etc. Previously, receptor-associated protein (RAP) was described as a molecular chaperone for LDLR-related protein 1 (LRP1), a prominent member of the LDLR family. We aimed to verify this role of RAP for LRP1 and two other LDLR family receptors, LDLR and vLDLR, and to investigate the mechanisms of respective interactions using a cell culture model system, purified system, and in silico modelling. Upon coexpression of RAP with clusters of the ligand-binding complement repeats (CRs) of the receptors in secreted form in insect cells culture, the isolated proteins had increased yield, enhanced folding, and improved binding properties compared with proteins expressed without RAP, as determined by circular dichroism and surface plasmon resonance. Within LRP1 CR-clusters II and IV, we identified multiple sites comprised of adjacent CR doublets, which provide alternative bivalent binding combinations with specific pairs of lysines on RAP. Mutational analysis of these lysines within each of isolated RAP D1/D2 and D3 domains having high affinity to LRP1 and of conserved tryptophans on selected CR-doublets of LRP1, as well as in silico docking of a model LRP1 CR-triplet with RAP, indicated a universal role for these residues in interaction of RAP and LRP1. Consequently, we propose a new model of RAP interaction with LDLR family receptors based on switching of the bivalent contacts between molecules over time in a dynamic mode.
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Affiliation(s)
- Ekaterina Marakasova
- Center for Biologics Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland, USA
| | - Philip Olivares
- Center for Biologics Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland, USA
| | - Elena Karnaukhova
- Center for Biologics Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland, USA
| | - Haarin Chun
- Center for Biologics Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland, USA
| | - Nancy E Hernandez
- Center for Biologics Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland, USA
| | - James H Kurasawa
- Center for Biologics Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland, USA
| | - Gabriela U Hassink
- Center for Biologics Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland, USA
| | - Svetlana A Shestopal
- Center for Biologics Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland, USA
| | - Dudley K Strickland
- Center for Vascular and Inflammatory Diseases, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Andrey G Sarafanov
- Center for Biologics Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland, USA.
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19
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A key requirement for synaptic Reelin signaling in ketamine-mediated behavioral and synaptic action. Proc Natl Acad Sci U S A 2021; 118:2103079118. [PMID: 33975959 PMCID: PMC8157952 DOI: 10.1073/pnas.2103079118] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Ketamine is a noncompetitive N-methyl-D-aspartate (NMDA) receptor antagonist that produces rapid antidepressant action in some patients with treatment-resistant depression. However, recent data suggest that ∼50% of patients with treatment-resistant depression do not respond to ketamine. The factors that contribute to the nonresponsiveness to ketamine's antidepressant action remain unclear. Recent studies have reported a role for secreted glycoprotein Reelin in regulating pre- and postsynaptic function, which suggests that Reelin may be involved in ketamine's antidepressant action, although the premise has not been tested. Here, we investigated whether the disruption of Reelin-mediated synaptic signaling alters ketamine-triggered synaptic plasticity and behavioral effects. To this end, we used mouse models with genetic deletion of Reelin or apolipoprotein E receptor 2 (Apoer2), as well as pharmacological inhibition of their downstream effectors, Src family kinases (SFKs) or phosphoinositide 3-kinase. We found that disruption of Reelin, Apoer2, or SFKs blocks ketamine-driven behavioral changes and synaptic plasticity in the hippocampal CA1 region. Although ketamine administration did not affect tyrosine phosphorylation of DAB1, an adaptor protein linked to downstream signaling of Reelin, disruption of Apoer2 or SFKs impaired baseline NMDA receptor-mediated neurotransmission. These results suggest that maintenance of baseline NMDA receptor function by Reelin signaling may be a key permissive factor required for ketamine's antidepressant effects. Taken together, our results suggest that impairments in Reelin-Apoer2-SFK pathway components may in part underlie nonresponsiveness to ketamine's antidepressant action.
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20
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Turk LS, Mitchell D, Comoletti D. Purification of a heterodimeric Reelin construct to investigate binding stoichiometry. EUROPEAN BIOPHYSICS JOURNAL : EBJ 2020; 49:773-779. [PMID: 33057791 PMCID: PMC7701066 DOI: 10.1007/s00249-020-01465-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 08/25/2020] [Accepted: 09/14/2020] [Indexed: 01/01/2023]
Abstract
Reelin is a secreted glycoprotein that is integral in neocortex development and synaptic function. Reelin exists as a homodimer with two chains linked by a disulfide bond at cysteine 2101, a feature that is vital to the protein's function. This is highlighted by the fact that only dimeric Reelin can elicit efficient, canonical signaling, even though a mutated (C2101A) monomeric construct of Reelin retains the capacity to bind to its receptors. Receptor clustering has been shown to be important in the signaling pathway, however direct evidence regarding the stoichiometry of Reelin-receptor binding interaction is lacking. Here we describe the construction and purification of a heterodimeric Reelin construct to investigate the stoichiometry of Reelin-receptor binding and how it affects Reelin pathway signaling. We have devised different strategies and have finalized a protocol to produce a heterodimer of Reelin's central fragment using differential tagging and tandem affinity chromatography, such that chain A is wild type in amino acid sequence whereas chain B includes a receptor binding site mutation (K2467A). We also validate that the heterodimer is capable of binding to the extracellular domain of one of Reelin's known receptors, calculating the KD of the interaction. This heterodimeric construct will enable us to understand in greater detail the mechanism by which Reelin interacts with its known receptors and initiates pathway signaling.
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Affiliation(s)
- Liam S Turk
- Child Health Institute of New Jersey, New Brunswick, NJ, 08901, USA.
- Department of Neuroscience and Cell Biology, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, New Brunswick, NJ, 08901, USA.
- School of Biological Sciences, Victoria University of Wellington, Wellington, 6012, New Zealand.
| | - Daniel Mitchell
- School of Biological Sciences, Victoria University of Wellington, Wellington, 6012, New Zealand
| | - Davide Comoletti
- Child Health Institute of New Jersey, New Brunswick, NJ, 08901, USA.
- Department of Neuroscience and Cell Biology, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, New Brunswick, NJ, 08901, USA.
- School of Biological Sciences, Victoria University of Wellington, Wellington, 6012, New Zealand.
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21
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Demir R, Şahar U, Deveci R. Determination of terminal glycan and total monosaccharide profiles of reelin glycoprotein in SH-SY5Y neuroblastoma cell line by lectin blotting and capillary liquid chromatography electrospray ionization-ion trap tandem mass spectrometry system. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2020; 1869:140559. [PMID: 33130090 DOI: 10.1016/j.bbapap.2020.140559] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 10/23/2020] [Accepted: 10/27/2020] [Indexed: 12/30/2022]
Abstract
Reelin (400 kDa) is an extracellular matrix glycoprotein that is a key regulator of the many significant biological processes including the brain formation, cell aggregation, and dendrite formation. The glycosylation contributes to the nature of the protein through folding, localization and trafficking, solubility, antigenicity, biological activity, and half-life. Although reelin is to be known as a glycoprotein, the knowledge of its glycosylation is very limited. In this study, we aimed to characterize the terminal glycan profile of reelin by lectin blotting and monosaccharide analysis of glycan chains by capillary liquid chromatography electrospray ionization ion trap tandem mass spectrometry (CapLC-ESI-MS/MS) in SH-SY5Y neuroblastoma cell line. According to our results, reelin was detected in different protein fragments (310, 250, and 85 kDa) in addition to full-length form (400 kDa) in the cell line. The reelin glycoprotein was found to carry the β-N-Acetylglucosamine, α-Mannose, β-Galactose, and α-2,3 and α2,6 linked sialic acids by lectin blotting. Nevertheless, these terminal monosaccharides were found in different intensity according to reelin fragments. Besides, we purified a reelin fragment (250 kDa), and we analyzed it for their monosaccharide by CapLC-ESI-MS/MS. We found that reelin contained five types of monosaccharides, which were consisted of N-Acetylgalactosamine, N-Acetylglucosamine, Galactose, Glucose, Mannose and Sialic acid, from high to low abundance respectively. The present results provide a valuable guide for biochemical, genetic, and glycobiology based further experiments about reelin glycosylation in cancer perspective.
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Affiliation(s)
- Ramiz Demir
- Ege University, Faculty of Science, Department of Biology, Molecular Biology Section, Izmir, Turkey
| | - Umut Şahar
- Ege University, Faculty of Science, Department of Biology, Molecular Biology Section, Izmir, Turkey.
| | - Remziye Deveci
- Ege University, Faculty of Science, Department of Biology, Molecular Biology Section, Izmir, Turkey.
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22
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Gallo CM, Ho A, Beffert U. ApoER2: Functional Tuning Through Splicing. Front Mol Neurosci 2020; 13:144. [PMID: 32848602 PMCID: PMC7410921 DOI: 10.3389/fnmol.2020.00144] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 07/13/2020] [Indexed: 11/13/2022] Open
Abstract
Alternative splicing occurs in over 95% of protein-coding genes and contributes to the diversity of the human proteome. Apolipoprotein E receptor 2 (apoER2) is a critical modulator of neuronal development and synaptic plasticity in the brain and is enriched in cassette exon splicing events, in which functional exons are excluded from the final transcript. These alternative splicing events affect apoER2 function, as individual apoER2 exons tend to encode distinct protein functional domains. Although several apoER2 splice variants have been characterized, much work remains to understand how apoER2 splicing events modulate distinct apoER2 activities, including ligand binding specificity, synapse formation and plasticity. Additionally, little is known about how apoER2 splicing events are regulated. Often, alternative splicing events are regulated through the combinatorial action of RNA-binding proteins and other epigenetic mechanisms, however, the regulatory pathways corresponding to each specific exon are unknown in most cases. In this mini-review, we describe the structure of apoER2, highlight the unique functions of known isoforms, discuss what is currently known about the regulation of apoER2 splicing by RNA-binding proteins and pose new questions that will further our understanding of apoER2 splicing complexity.
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Affiliation(s)
- Christina M Gallo
- Department of Biology, Boston University, Boston, MA, United States.,Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA, United States
| | - Angela Ho
- Department of Biology, Boston University, Boston, MA, United States.,Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA, United States
| | - Uwe Beffert
- Department of Biology, Boston University, Boston, MA, United States
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23
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Yu J, Cho E, Choi YG, Jeong YK, Na Y, Kim JS, Cho SR, Woo JS, Bae S. Purification of an Intact Human Protein Overexpressed from Its Endogenous Locus via Direct Genome Engineering. ACS Synth Biol 2020; 9:1591-1598. [PMID: 32584551 DOI: 10.1021/acssynbio.0c00090] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The overproduction and purification of human proteins is a requisite of both basic and medical research. Although many recombinant human proteins have been purified, current protein production methods have several limitations; recombinant proteins are frequently truncated, fail to fold properly, and/or lack appropriate post-translational modifications. In addition, such methods require subcloning of the target gene into relevant plasmids, which can be difficult for long proteins with repeated domains. Here we devised a novel method for target protein production by introduction of a strong promoter for overexpression and an epitope tag for purification in front of the endogenous human gene, in a sense performing molecular cloning directly in the human genome, which does not require cloning of the target gene. As a proof of concept, we successfully purified intact human Reelin protein, which is lengthy (3460 amino acids) and contains repeating domains, and confirmed that it was biologically functional.
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Affiliation(s)
- Jihyeon Yu
- Department of Chemistry, Hanyang University, Seoul 04763, South Korea
- Research Institute for Convergence of Basic Sciences, Hanyang University, Seoul 04763, South Korea
| | - Eunju Cho
- Department and Research Institute of Rehabilitation Medicine, Yonsei University College of Medicine, Seoul 03722, South Korea
- Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul 03722, South Korea
| | - Yeon-Gil Choi
- Department of Life Sciences, Korea University, Seoul 02841, South Korea
| | - You Kyeong Jeong
- Department of Chemistry, Hanyang University, Seoul 04763, South Korea
- Research Institute for Convergence of Basic Sciences, Hanyang University, Seoul 04763, South Korea
| | - Yongwoo Na
- Center for RNA Research, Institute for Basic Science (IBS), Seoul 08826, South Korea
- School of Biological Sciences, Seoul National University, Seoul 08826, South Korea
| | - Jong-Seo Kim
- Center for RNA Research, Institute for Basic Science (IBS), Seoul 08826, South Korea
- School of Biological Sciences, Seoul National University, Seoul 08826, South Korea
| | - Sung-Rae Cho
- Department and Research Institute of Rehabilitation Medicine, Yonsei University College of Medicine, Seoul 03722, South Korea
- Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul 03722, South Korea
- Graduate Program of Nano Science and Technology, Yonsei University College of Medicine, Seoul 03722, South Korea
| | - Jae-Sung Woo
- Department of Life Sciences, Korea University, Seoul 02841, South Korea
| | - Sangsu Bae
- Department of Chemistry, Hanyang University, Seoul 04763, South Korea
- Research Institute for Convergence of Basic Sciences, Hanyang University, Seoul 04763, South Korea
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24
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Jossin Y. Reelin Functions, Mechanisms of Action and Signaling Pathways During Brain Development and Maturation. Biomolecules 2020; 10:biom10060964. [PMID: 32604886 PMCID: PMC7355739 DOI: 10.3390/biom10060964] [Citation(s) in RCA: 87] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 06/24/2020] [Accepted: 06/24/2020] [Indexed: 12/14/2022] Open
Abstract
During embryonic development and adulthood, Reelin exerts several important functions in the brain including the regulation of neuronal migration, dendritic growth and branching, dendritic spine formation, synaptogenesis and synaptic plasticity. As a consequence, the Reelin signaling pathway has been associated with several human brain disorders such as lissencephaly, autism, schizophrenia, bipolar disorder, depression, mental retardation, Alzheimer’s disease and epilepsy. Several elements of the signaling pathway are known. Core components, such as the Reelin receptors very low-density lipoprotein receptor (VLDLR) and Apolipoprotein E receptor 2 (ApoER2), Src family kinases Src and Fyn, and the intracellular adaptor Disabled-1 (Dab1), are common to most but not all Reelin functions. Other downstream effectors are, on the other hand, more specific to defined tasks. Reelin is a large extracellular protein, and some aspects of the signal are regulated by its processing into smaller fragments. Rather than being inhibitory, the processing at two major sites seems to be fulfilling important physiological functions. In this review, I describe the various cellular events regulated by Reelin and attempt to explain the current knowledge on the mechanisms of action. After discussing the shared and distinct elements of the Reelin signaling pathway involved in neuronal migration, dendritic growth, spine development and synaptic plasticity, I briefly outline the data revealing the importance of Reelin in human brain disorders.
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Affiliation(s)
- Yves Jossin
- Laboratory of Mammalian Development & Cell Biology, Institute of Neuroscience, Université Catholique de Louvain, 1200 Brussels, Belgium
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25
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Roberts BL, Bennett BJ, Bennett CM, Carroll JM, Dalbøge LS, Hall C, Hassouneh W, Heppner KM, Kirigiti MA, Lindsley SR, Tennant KG, True CA, Whittle A, Wolf AC, Roberts CT, Tang-Christensen M, Sleeman MW, Cowley MA, Grove KL, Kievit P. Reelin is modulated by diet-induced obesity and has direct actions on arcuate proopiomelanocortin neurons. Mol Metab 2019; 26:18-29. [PMID: 31230943 PMCID: PMC6667498 DOI: 10.1016/j.molmet.2019.06.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 05/22/2019] [Accepted: 06/04/2019] [Indexed: 11/26/2022] Open
Abstract
Objective Reelin (RELN) is a large glycoprotein involved in synapse maturation and neuronal organization throughout development. Deficits in RELN signaling contribute to multiple psychological disorders, such as autism spectrum disorder, schizophrenia, and bipolar disorder. Nutritional stress alters RELN expression in brain regions associated with these disorders; however, the involvement of RELN in the neural circuits involved in energy metabolism is unknown. The RELN receptors apolipoprotein E receptor 2 (ApoER2) and very low-density lipoprotein receptor (VLDLR) are involved in lipid metabolism and expressed in the hypothalamus. Here we explored the involvement of RELN in hypothalamic signaling and the impact of diet-induced obesity (DIO) on this system. Methods Adult male mice were fed a chow diet or maintained on a high-fat diet (HFD) for 12–16 weeks. HFD-fed DIO mice exhibited decreased ApoER2 and VLDLR expression and increased RELN protein in the hypothalamus. Electrophysiology was used to determine the mechanism by which the central fragment of RELN (CF-RELN) acts on arcuate nucleus (ARH) satiety-promoting proopiomelanocortin (POMC) neurons and the impact of DIO on this circuitry. Results CF-RELN exhibited heterogeneous presynaptic actions on inhibitory inputs onto ARH-POMC-EGFP neurons and consistent postsynaptic actions. Additionally, central administration of CF-RELN caused a significant increase in ARH c-Fos expression and an acute decrease in food intake and body weight. Conclusions We conclude that RELN signaling is modulated by diet, that RELN is involved in synaptic signaling onto ARH-POMC neurons, and that altering central CF-RELN levels can impact food intake and body weight. Diet-induced obesity alters reelin protein levels and expression of ApoER2 and VLDLR. Reelin has direct, but divergent actions on GABAergic inputs onto POMC neurons. Central administration of reelin protein decreases food intake and body weight.
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Affiliation(s)
- Brandon L Roberts
- Division of Cardiometabolic Health, Oregon National Primate Research Center, Beaverton, OR, 97006, USA
| | - Baylin J Bennett
- Division of Cardiometabolic Health, Oregon National Primate Research Center, Beaverton, OR, 97006, USA
| | - Camdin M Bennett
- Division of Cardiometabolic Health, Oregon National Primate Research Center, Beaverton, OR, 97006, USA
| | - Julie M Carroll
- Division of Cardiometabolic Health, Oregon National Primate Research Center, Beaverton, OR, 97006, USA
| | | | - Colin Hall
- Obesity Research Center, Novo Nordisk, Seattle, WA, 98109, USA
| | - Wafa Hassouneh
- Obesity Research Center, Novo Nordisk, Seattle, WA, 98109, USA
| | | | - Melissa A Kirigiti
- Division of Cardiometabolic Health, Oregon National Primate Research Center, Beaverton, OR, 97006, USA
| | - Sarah R Lindsley
- Division of Cardiometabolic Health, Oregon National Primate Research Center, Beaverton, OR, 97006, USA
| | - Katherine G Tennant
- Division of Cardiometabolic Health, Oregon National Primate Research Center, Beaverton, OR, 97006, USA
| | - Cadence A True
- Division of Cardiometabolic Health, Oregon National Primate Research Center, Beaverton, OR, 97006, USA
| | - Andrew Whittle
- Obesity Research Center, Novo Nordisk, Seattle, WA, 98109, USA
| | - Anitra C Wolf
- Obesity Research Center, Novo Nordisk, Seattle, WA, 98109, USA
| | - Charles T Roberts
- Division of Cardiometabolic Health, Oregon National Primate Research Center, Beaverton, OR, 97006, USA
| | | | - Mark W Sleeman
- Department of Physiology, Monash University Biomedicine Discovery Institute, Clayton, Victoria, Australia
| | - Michael A Cowley
- Department of Physiology, Monash University Biomedicine Discovery Institute, Clayton, Victoria, Australia
| | - Kevin L Grove
- Obesity Research Center, Novo Nordisk, Seattle, WA, 98109, USA
| | - Paul Kievit
- Division of Cardiometabolic Health, Oregon National Primate Research Center, Beaverton, OR, 97006, USA.
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26
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Armstrong NC, Anderson RC, McDermott KW. Reelin: Diverse roles in central nervous system development, health and disease. Int J Biochem Cell Biol 2019; 112:72-75. [PMID: 31022460 DOI: 10.1016/j.biocel.2019.04.009] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Revised: 04/09/2019] [Accepted: 04/20/2019] [Indexed: 11/25/2022]
Abstract
Over the past 20 years the structure and function of Reelin, an extracellular glycoprotein with a role in cell migration and positioning during development has been elucidated. Originally discovered in mice exhibiting a peculiar gait and hypoplastic cerebellar tissue, Reelin is secreted from Cajal-Retzius neurons during embryonic life and has been shown to act as a stop signal, guiding migrating radial neurons in a gradient-dependent manner. Reelin carries out its function by binding to the receptors, very low-density lipoprotein receptor (VLDLR) and apolipoprotein E receptor 2 (ApoER2) resulting in the phosphorylation of the intracellular protein Disabled-1 (Dab-1) which is essential for effective Reelin signaling. Abnormalities in the RELN gene can result in multiple unusual structural outcomes including disruption of cortical layers, heterotopia, polymicrogyria and lissencephaly. Recent research has suggested a potential role for Reelin in the pathogenesis of neurological diseases such as schizophrenia, autism and Alzheimer's disease. This short review will address the current understanding of the structure and function of this protein and its emerging role in the development of neurological disorders.
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Affiliation(s)
| | - Rebecca C Anderson
- Graduate Entry Medical School, University of Limerick, Limerick, Ireland
| | - Kieran W McDermott
- Graduate Entry Medical School and Health Research Institute, University of Limerick, Limerick, Ireland.
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27
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Haque MN, Moon IS. Stigmasterol promotes neuronal migration via reelin signaling in neurosphere migration assays. Nutr Neurosci 2018; 23:679-687. [PMID: 30433855 DOI: 10.1080/1028415x.2018.1544970] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Stigmasterol (ST) is a multifunctional phytosterol and is found in diverse food. In our previous transcriptomics study, we found ST upregulated migration-related genes. In the present study, we carried out in vitro neurosphere migration assays to investigate the effects of ST on neuronal migration. For this purpose, neurospheres were produced by culturing rat (Sprague-Dawley) E14 cortical neurons. The addition of ST (75 μM) to culture medium increased not only the numbers of migratory neurons by 15% but the distance of movement up to 120 μm from the centers of neurospheres as compared to vehicle cultures. Immunocytochemistry and immunoblotting showed ST upregulated the expressions of Reelin (Reln) and its downstream signaling molecules like phospho-JNK (c-Jun N-terminal kinase), doublecortin (DCX) and dynein heavy chain (DHC) in migratory neurons. Furthermore, in silico molecular docking simulation indicated that ST interacts with Relin receptor ApoER2 by forming a hydrogen bond with Lys2467 and other van der Waals interactions. Taken together, our study shows that ST upregulates Reln signaling and promotes neuronal migration and suggests that ST supplementation is considered as a potential means of treating migration-related CNS disorders.
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Affiliation(s)
- Md Nazmul Haque
- Department of Anatomy, Dongguk University Graduate School of Medicine, Gyeongju 38066, Republic of Korea
| | - Il Soo Moon
- Department of Anatomy, Dongguk University Graduate School of Medicine, Gyeongju 38066, Republic of Korea
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28
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Sánchez-Sánchez SM, Magdalon J, Griesi-Oliveira K, Yamamoto GL, Santacruz-Perez C, Fogo M, Passos-Bueno MR, Sertié AL. Rare RELN variants affect Reelin-DAB1 signal transduction in autism spectrum disorder. Hum Mutat 2018; 39:1372-1383. [PMID: 29969175 DOI: 10.1002/humu.23584] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 06/25/2018] [Accepted: 06/29/2018] [Indexed: 11/07/2022]
Abstract
The Reelin-DAB1 signaling pathway plays a crucial role in regulating neuronal migration and synapse function. Although many rare heterozygous variants in the Reelin gene (RELN) have been identified in patients with autism spectrum disorder (ASD), most variants are still of unknown clinical significance. Also, genetic data suggest that heterozygous variants in RELN alone appear to be insufficient to cause ASD. Here, we describe the identification and functional characterization of rare compound heterozygous missense variants in RELN in a patient with ASD in whom we have previously reported hyperfunctional mTORC1 signaling of yet unknown etiology. Using iPSC-derived neural progenitor cells (NPCs) from this patient, we provide experimental evidence that the identified variants are deleterious and lead to diminished Reelin secretion and impaired Reelin-DAB1 signal transduction. Also, our results suggest that mTORC1 pathway overactivation may function as a second hit event contributing to downregulation of the Reelin-DAB1 cascade in patient-derived NPCs, and that inhibition of mTORC1 by rapamycin attenuates Reelin-DAB1 signaling impairment. Taken together, our findings point to an abnormal interplay between Reelin-DAB1 and mTORC1 networks in nonsyndromic ASD.
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Affiliation(s)
- Sandra M Sánchez-Sánchez
- Center for Experimental Research, Hospital Israelita Albert Einstein, Sao Paulo, Brazil.,Department of Genetics and Evolutionary Biology, Sao Paulo University, Sao Paulo, Brazil
| | - Juliana Magdalon
- Center for Experimental Research, Hospital Israelita Albert Einstein, Sao Paulo, Brazil
| | | | - Guilherme L Yamamoto
- Department of Genetics and Evolutionary Biology, Sao Paulo University, Sao Paulo, Brazil
| | | | - Mariana Fogo
- Center for Experimental Research, Hospital Israelita Albert Einstein, Sao Paulo, Brazil.,Department of Genetics and Evolutionary Biology, Sao Paulo University, Sao Paulo, Brazil
| | | | - Andrea L Sertié
- Center for Experimental Research, Hospital Israelita Albert Einstein, Sao Paulo, Brazil
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29
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Molinard-Chenu A, Dayer A. The Candidate Schizophrenia Risk Gene DGCR2 Regulates Early Steps of Corticogenesis. Biol Psychiatry 2018; 83:692-706. [PMID: 29305086 DOI: 10.1016/j.biopsych.2017.11.015] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Revised: 11/06/2017] [Accepted: 11/06/2017] [Indexed: 02/08/2023]
Abstract
BACKGROUND Alterations in early steps of cortical circuit assembly are thought to play a critical role in vulnerability to schizophrenia (SZ), but the pathogenic impact of SZ-risk mutations on corticogenesis remains to be determined. DiGeorge syndrome critical region 2 (DGCR2) is located in the 22q11.2 locus, whose deletion is a major risk factor for SZ. Moreover, exome sequencing of individuals with idiopathic SZ identified a rare missense mutation in DGCR2, further suggesting that DGCR2 is involved in SZ. METHODS Here we investigated the function of Dgcr2 and the pathogenic impact of the SZ-risk DGCR2 mutation in mouse corticogenesis using in utero electroporation targeted to projection neurons. RESULTS Dgcr2 knockdown impaired radial locomotion and final translocation of projection neurons, leading to persistent laminar positioning alterations. The DGCR2 missense SZ-risk mutation had a pathogenic impact on projection neuron laminar allocation by reducing protein expression. Mechanistically, we identified Dgcr2 as a novel member of the Reelin complex, regulating the phosphorylation of Reelin-dependent substrates and the expression of Reelin-dependent transcriptional targets. CONCLUSIONS Overall, this study provides biological evidence that the SZ-risk gene DGCR2 regulates critical steps of early corticogenesis possibly through a Reelin-dependent mechanism. Additionally, we found that the SZ-risk mutation in DGCR2 has a pathogenic impact on cortical formation by reducing protein expression level, suggesting a functional role for DGCR2 haploinsufficiency in the 22q11.2 deletion syndrome.
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Affiliation(s)
- Aude Molinard-Chenu
- Department of Psychiatry, University of Geneva Medical School, Geneva, Switzerland; Department of Basic Neurosciences, University of Geneva Medical School, Geneva, Switzerland; Institute of Genetics and Genomics in Geneva, University of Geneva Medical Center, Geneva, Switzerland
| | - Alexandre Dayer
- Department of Psychiatry, University of Geneva Medical School, Geneva, Switzerland; Department of Basic Neurosciences, University of Geneva Medical School, Geneva, Switzerland; Institute of Genetics and Genomics in Geneva, University of Geneva Medical Center, Geneva, Switzerland.
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30
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Wang S, Mao Y, Narimatsu Y, Ye Z, Tian W, Goth CK, Lira-Navarrete E, Pedersen NB, Benito-Vicente A, Martin C, Uribe KB, Hurtado-Guerrero R, Christoffersen C, Seidah NG, Nielsen R, Christensen EI, Hansen L, Bennett EP, Vakhrushev SY, Schjoldager KT, Clausen H. Site-specific O-glycosylation of members of the low-density lipoprotein receptor superfamily enhances ligand interactions. J Biol Chem 2018; 293:7408-7422. [PMID: 29559555 DOI: 10.1074/jbc.m117.817981] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Revised: 02/27/2018] [Indexed: 11/06/2022] Open
Abstract
The low-density lipoprotein receptor (LDLR) and related receptors are important for the transport of diverse biomolecules across cell membranes and barriers. Their functions are especially relevant for cholesterol homeostasis and diseases, including neurodegenerative and kidney disorders. Members of the LDLR-related protein family share LDLR class A (LA) repeats providing binding properties for lipoproteins and other biomolecules. We previously demonstrated that short linker regions between these LA repeats contain conserved O-glycan sites. Moreover, we found that O-glycan modifications at these sites are selectively controlled by the GalNAc-transferase isoform, GalNAc-T11. However, the effects of GalNAc-T11-mediated O-glycosylation on LDLR and related receptor localization and function are unknown. Here, we characterized O-glycosylation of LDLR-related proteins and identified conserved O-glycosylation sites in the LA linker regions of VLDLR, LRP1, and LRP2 (Megalin) from both cell lines and rat organs. Using a panel of gene-edited isogenic cell line models, we demonstrate that GalNAc-T11-mediated LDLR and VLDLR O-glycosylation is not required for transport and cell-surface expression and stability of these receptors but markedly enhances LDL and VLDL binding and uptake. Direct ELISA-based binding assays with truncated LDLR constructs revealed that O-glycosylation increased affinity for LDL by ∼5-fold. The molecular basis for this observation is currently unknown, but these findings open up new avenues for exploring the roles of LDLR-related proteins in disease.
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Affiliation(s)
- Shengjun Wang
- Copenhagen Center for Glycomics, Departments of Cellular and Molecular Medicine and School of Dentistry, Faculty of Health Sciences, University of Copenhagen, DK-2200 Copenhagen N, Denmark
| | - Yang Mao
- Copenhagen Center for Glycomics, Departments of Cellular and Molecular Medicine and School of Dentistry, Faculty of Health Sciences, University of Copenhagen, DK-2200 Copenhagen N, Denmark
| | - Yoshiki Narimatsu
- Copenhagen Center for Glycomics, Departments of Cellular and Molecular Medicine and School of Dentistry, Faculty of Health Sciences, University of Copenhagen, DK-2200 Copenhagen N, Denmark
| | - Zilu Ye
- Copenhagen Center for Glycomics, Departments of Cellular and Molecular Medicine and School of Dentistry, Faculty of Health Sciences, University of Copenhagen, DK-2200 Copenhagen N, Denmark
| | - Weihua Tian
- Copenhagen Center for Glycomics, Departments of Cellular and Molecular Medicine and School of Dentistry, Faculty of Health Sciences, University of Copenhagen, DK-2200 Copenhagen N, Denmark
| | - Christoffer K Goth
- Copenhagen Center for Glycomics, Departments of Cellular and Molecular Medicine and School of Dentistry, Faculty of Health Sciences, University of Copenhagen, DK-2200 Copenhagen N, Denmark
| | - Erandi Lira-Navarrete
- Copenhagen Center for Glycomics, Departments of Cellular and Molecular Medicine and School of Dentistry, Faculty of Health Sciences, University of Copenhagen, DK-2200 Copenhagen N, Denmark
| | - Nis B Pedersen
- Copenhagen Center for Glycomics, Departments of Cellular and Molecular Medicine and School of Dentistry, Faculty of Health Sciences, University of Copenhagen, DK-2200 Copenhagen N, Denmark
| | - Asier Benito-Vicente
- Biofisika Institute, Centro Superior de Investigaciones Cientificas (CSIC), Universidad del Pais Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), and Departamento de Bioquimica, Universidad del Pais Vasco, 48080 Bilbao, Spain
| | - Cesar Martin
- Biofisika Institute, Centro Superior de Investigaciones Cientificas (CSIC), Universidad del Pais Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), and Departamento de Bioquimica, Universidad del Pais Vasco, 48080 Bilbao, Spain
| | - Kepa B Uribe
- Biofisika Institute, Centro Superior de Investigaciones Cientificas (CSIC), Universidad del Pais Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), and Departamento de Bioquimica, Universidad del Pais Vasco, 48080 Bilbao, Spain
| | - Ramon Hurtado-Guerrero
- The Institute for Biocomputation and Physics of Complex Systems (BIFI), University of Zaragoza, BIFI-Instituto de Química Física Rocasolano (IQFR), CSIC Joint Unit, Mariano Esquillor s/n, Campus Rio Ebro, 50009 Zaragoza, Spain
| | - Christina Christoffersen
- Department of Clinical Biochemistry, Rigshospitalet and Department of Biomedical Sciences, University of Copenhagen, Copenhagen 2100, Denmark
| | - Nabil G Seidah
- Clinical Research Institute of Montreal, University of Montreal, Montreal, Quebec H2W 1R7, Canada
| | - Rikke Nielsen
- Department of Biomedicine, Aarhus University, DK-8000 Aarhus, Denmark
| | | | - Lars Hansen
- Copenhagen Center for Glycomics, Departments of Cellular and Molecular Medicine and School of Dentistry, Faculty of Health Sciences, University of Copenhagen, DK-2200 Copenhagen N, Denmark
| | - Eric P Bennett
- Copenhagen Center for Glycomics, Departments of Cellular and Molecular Medicine and School of Dentistry, Faculty of Health Sciences, University of Copenhagen, DK-2200 Copenhagen N, Denmark
| | - Sergey Y Vakhrushev
- Copenhagen Center for Glycomics, Departments of Cellular and Molecular Medicine and School of Dentistry, Faculty of Health Sciences, University of Copenhagen, DK-2200 Copenhagen N, Denmark
| | - Katrine T Schjoldager
- Copenhagen Center for Glycomics, Departments of Cellular and Molecular Medicine and School of Dentistry, Faculty of Health Sciences, University of Copenhagen, DK-2200 Copenhagen N, Denmark.
| | - Henrik Clausen
- Copenhagen Center for Glycomics, Departments of Cellular and Molecular Medicine and School of Dentistry, Faculty of Health Sciences, University of Copenhagen, DK-2200 Copenhagen N, Denmark.
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How multi-scale structural biology elucidated context-dependent variability in ectodomain conformation along with the ligand capture and release cycle for LDLR family members. Biophys Rev 2017; 10:481-492. [PMID: 29204877 DOI: 10.1007/s12551-017-0362-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 11/19/2017] [Indexed: 12/25/2022] Open
Abstract
The low-density lipoprotein receptor (LDLR) and its homologs capture and internalize lipoproteins into the cell. Due to the fact that LDLR family members possess a modular ectodomain that undergoes dynamic conformational changes, multi-scale structural analysis has been performed so as to understand the ligand capture and release mechanism. For example, crystallographic analyses have provided models for both the entire ectodomain and high-resolution structures of individual modules. In addition, nuclear magnetic resonance spectroscopic analyses have shown the rigidity and flexibility of inter-module linkers to restrict the mobility of ectodomain. Accumulated structural data suggest that the ectodomains of LDLR family members are flexible at the cell surface and switch between two metastable conformations, that is, the extended and contracted conformations. Recent structural analysis of ApoER2, a close homolog of LDLR, raised the possibility that the receptor binds with the ligand in the contracted conformation. After transport to an endosome by endocytosis, the receptor undergoes a conformational change to the closed conformation for completion of ligand release. In contrast, LDLR has been reported to adopt the extended conformation when it binds with a inhibitory regulator that recruits LDLR toward the degradation pathway. These findings support a mechanism of different ectodomain conformations for binding the ligand versus binding the regulatory protein. In this review, I provide an overview of studies that analyze the structural and biophysical properties of the ectodomains of LDLR family members and discuss a hypothetical model for ligand uptake and receptor recycling that integrates the known ectodomain conformational variability.
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Distinct activation modes of the Relaxin Family Peptide Receptor 2 in response to insulin-like peptide 3 and relaxin. Sci Rep 2017; 7:3294. [PMID: 28607406 PMCID: PMC5468325 DOI: 10.1038/s41598-017-03638-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Accepted: 05/02/2017] [Indexed: 11/16/2022] Open
Abstract
Relaxin family peptide receptor 2 (RXFP2) is a GPCR known for its role in reproductive function. It is structurally related to the human relaxin receptor RXFP1 and can be activated by human gene-2 (H2) relaxin as well as its cognate ligand insulin-like peptide 3 (INSL3). Both receptors possess an N-terminal low-density lipoprotein type a (LDLa) module that is necessary for activation and is joined to a leucine-rich repeat domain by a linker. This linker has been shown to be important for H2 relaxin binding and activation of RXFP1 and herein we investigate the role of the equivalent region of RXFP2. We demonstrate that the linker’s highly-conserved N-terminal region is essential for activation of RXFP2 in response to both ligands. In contrast, the linker is necessary for H2 relaxin, but not INSL3, binding. Our results highlight the distinct mechanism by which INSL3 activates RXFP2 whereby ligand binding mediates reorientation of the LDLa module by the linker region to activate the RXFP2 transmembrane domains in conjunction with the INSL3 A-chain. In contrast, relaxin activation of RXFP2 involves a more RXFP1-like mechanism involving binding to the LDLa-linker, reorientation of the LDLa module and activation of the transmembrane domains by the LDLa alone.
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Lammert DB, Middleton FA, Pan J, Olson EC, Howell BW. The de novo autism spectrum disorder RELN R2290C mutation reduces Reelin secretion and increases protein disulfide isomerase expression. J Neurochem 2017; 142:89-102. [PMID: 28419454 DOI: 10.1111/jnc.14045] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Revised: 03/22/2017] [Accepted: 04/05/2017] [Indexed: 12/11/2022]
Abstract
Despite the recent identification of over 40 missense heterozygous Reelin gene (RELN) mutations in autism spectrum disorder (ASD), none of these has been functionally characterized. Reelin is an integral signaling ligand for proper brain development and post-natal synapse function - properties likely disrupted in ASD patients. We find that the R2290C mutation, which arose de novo in an affected ASD proband, and other analogous mutations in arginine-amino acid-arginine domains reduce protein secretion. Closer analysis of RELN R2290C heterozygous neurospheres reveals up-regulation of Protein Disulfide Isomerase A1, best known as an endoplasmic reticulum-chaperone protein, which has been linked to neuronal pathology. This effect is recapitulated in a heterozygous RELN mouse mutant that is characterized by defective Reelin secretion. These findings suggest that both a deficiency in Reelin signaling and pathologic impairment of Reelin secretion may contribute to ASD risk.
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Affiliation(s)
- Dawn B Lammert
- Department of Neuroscience and Physiology, SUNY Upstate Medical University, Syracuse, New York, USA
| | - Frank A Middleton
- Department of Neuroscience and Physiology, SUNY Upstate Medical University, Syracuse, New York, USA
| | - Jen Pan
- The Broad Institute, Stanley Center Neurobiology, Cambridge, Massachusetts, USA
| | - Eric C Olson
- Department of Neuroscience and Physiology, SUNY Upstate Medical University, Syracuse, New York, USA
| | - Brian W Howell
- Department of Neuroscience and Physiology, SUNY Upstate Medical University, Syracuse, New York, USA
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Yakovlev S, Medved L. Interaction of Fibrin with the Very Low-Density Lipoprotein (VLDL) Receptor: Further Characterization and Localization of the VLDL Receptor-Binding Site in Fibrin βN-Domains. Biochemistry 2017; 56:2518-2528. [PMID: 28437098 DOI: 10.1021/acs.biochem.7b00087] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Our recent study revealed that fibrin and the very low-density lipoprotein receptor (VLDLR) interact with each other through a pair of fibrin βN-domains and CR domains of the receptor and this interaction promotes transendothelial migration of leukocytes and thereby inflammation. The major objectives of this study were to further clarify the molecular mechanism of fibrin-VLDLR interaction and to identify amino acid residues in the βN-domains involved in this interaction. Our binding experiments with the (β15-66)2 fragment, which corresponds to a pair of fibrin βN-domains, and the VLDLR(1-8) fragment, consisting of eight CR domains of VLDLR, revealed that interaction between them strongly depends on ionic strength and chemical modification of all Lys or Arg residues in (β15-66)2 results in abrogation of this interaction. To identify which of these residues are involved in the interaction, we mutated all Lys or Arg residues in each of the three positively charged Lys/Arg clusters of the (β15-66)2 fragment, as well as single Arg17 and Arg30, and tested the affinity of the mutants obtained for VLDLR(1-8) by an enzyme-linked immunosorbent assay and surface plasmon resonance. The experiments revealed that the second and third Lys/Arg clusters make the major contribution to this interaction while the contribution of the first cluster is moderate. The results obtained suggest that interaction between fibrin and the VLDL receptor employs the "double-Lys/Arg" recognition mode previously proposed for the interaction of the LDL receptor family members with their ligands. They also provide valuable information for the development of highly specific peptide-based inhibitors of fibrin-VLDLR interaction.
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Affiliation(s)
- Sergiy Yakovlev
- Center for Vascular and Inflammatory Diseases and Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine , Baltimore, Maryland 21201, United States
| | - Leonid Medved
- Center for Vascular and Inflammatory Diseases and Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine , Baltimore, Maryland 21201, United States
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Hirai H, Yasui N, Yamashita K, Tabata S, Yamamoto M, Takagi J, Nogi T. Structural basis for ligand capture and release by the endocytic receptor ApoER2. EMBO Rep 2017; 18:982-999. [PMID: 28446613 PMCID: PMC5452030 DOI: 10.15252/embr.201643521] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Revised: 03/09/2017] [Accepted: 03/15/2017] [Indexed: 11/09/2022] Open
Abstract
Apolipoprotein E receptor 2 (ApoER2) is a close homologue of low-density lipoprotein receptor (LDLR) that mediates the endocytosis of ligands, including LDL particles. LDLR family members have been presumed to explore a large conformational space to capture ligands in the extended conformation at the cell surface. Ligands are subsequently released through a pH-titrated structural transition to a self-docked, contracted-closed conformation. In addition to lipoprotein uptake, ApoER2 is implicated in signal transduction during brain development through capture of the extracellular protein reelin. From crystallographic analysis, we determine that the full-length ApoER2 ectodomain adopts an intermediate contracted-open conformation when complexed with the signaling-competent reelin fragment, and we identify a previously unappreciated auxiliary low-affinity binding interface. Based on mutational analyses, we propose that the pH shift during endocytosis weakens the affinity of the auxiliary interface and destabilizes the ligand-receptor complex. Furthermore, this study elucidates that the contracted-open conformation of ligand-bound ApoER2 at neutral pH resembles the contracted-closed conformation of ligand-unbound LDLR at acidic pH in a manner suggestive of being primed for ligand release even prior to internalization.
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Affiliation(s)
- Hidenori Hirai
- Institute for Protein Research, Osaka University, Osaka, Japan
| | - Norihisa Yasui
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | | | - Sanae Tabata
- Institute for Protein Research, Osaka University, Osaka, Japan
| | | | - Junichi Takagi
- Institute for Protein Research, Osaka University, Osaka, Japan
| | - Terukazu Nogi
- Graduate School of Medical Life Science, Yokohama City University, Yokohama, Japan
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Orcinha C, Münzner G, Gerlach J, Kilias A, Follo M, Egert U, Haas CA. Seizure-Induced Motility of Differentiated Dentate Granule Cells Is Prevented by the Central Reelin Fragment. Front Cell Neurosci 2016; 10:183. [PMID: 27516734 PMCID: PMC4963407 DOI: 10.3389/fncel.2016.00183] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 07/08/2016] [Indexed: 12/01/2022] Open
Abstract
Granule cell dispersion (GCD) represents a pathological widening of the granule cell layer in the dentate gyrus and it is frequently observed in patients with mesial temporal lobe epilepsy (MTLE). Recent studies in human MTLE specimens and in animal epilepsy models have shown that a decreased expression and functional inactivation of the extracellular matrix protein Reelin correlates with GCD formation, but causal evidence is still lacking. Here, we used unilateral kainate (KA) injection into the mouse hippocampus, an established MTLE animal model, to precisely map the loss of reelin mRNA-synthesizing neurons in relation to GCD along the septotemporal axis of the epileptic hippocampus. We show that reelin mRNA-producing neurons are mainly lost in the hilus and that this loss precisely correlates with the occurrence of GCD. To monitor GCD formation in real time, we used organotypic hippocampal slice cultures (OHSCs) prepared from mice which express enhanced green fluorescent protein (eGFP) primarily in differentiated dentate granule cells. Using life cell microscopy we observed that increasing doses of KA resulted in an enhanced motility of eGFP-positive granule cells. Moreover, KA treatment of OHSC resulted in a rapid loss of Reelin-producing interneurons mainly in the hilus, as observed in vivo. A detailed analysis of the migration behavior of individual eGFP-positive granule cells revealed that the majority of these neurons actively migrate toward the hilar region, where Reelin-producing neurons are lost. Treatment with KA and subsequent addition of the recombinant R3–6 Reelin fragment significantly prevented the movement of eGFP-positive granule cells. Together, these findings suggest that GCD formation is indeed triggered by a loss of Reelin in hilar interneurons.
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Affiliation(s)
- Catarina Orcinha
- Experimental Epilepsy Research, Department of Neurosurgery, Medical Center, University of FreiburgFreiburg, Germany; Faculty of Medicine, University of FreiburgFreiburg, Germany; Faculty of Biology, University of FreiburgFreiburg, Germany; Bernstein Center Freiburg, University of FreiburgFreiburg, Germany
| | - Gert Münzner
- Experimental Epilepsy Research, Department of Neurosurgery, Medical Center, University of FreiburgFreiburg, Germany; Faculty of Medicine, University of FreiburgFreiburg, Germany; Faculty of Biology, University of FreiburgFreiburg, Germany
| | - Johannes Gerlach
- Experimental Epilepsy Research, Department of Neurosurgery, Medical Center, University of FreiburgFreiburg, Germany; Faculty of Medicine, University of FreiburgFreiburg, Germany; Faculty of Biology, University of FreiburgFreiburg, Germany
| | - Antje Kilias
- Faculty of Biology, University of FreiburgFreiburg, Germany; Bernstein Center Freiburg, University of FreiburgFreiburg, Germany; Laboratory for Biomicrotechnology, Department of Microsystems Engineering, University of FreiburgFreiburg, Germany
| | - Marie Follo
- Faculty of Medicine, University of FreiburgFreiburg, Germany; Lighthouse Core Facility, Department of Medicine I, Medical Center, University of FreiburgFreiburg, Germany
| | - Ulrich Egert
- Bernstein Center Freiburg, University of FreiburgFreiburg, Germany; Laboratory for Biomicrotechnology, Department of Microsystems Engineering, University of FreiburgFreiburg, Germany; BrainLinks-BrainTools, Cluster of Excellence, University of FreiburgFreiburg, Germany
| | - Carola A Haas
- Experimental Epilepsy Research, Department of Neurosurgery, Medical Center, University of FreiburgFreiburg, Germany; Faculty of Medicine, University of FreiburgFreiburg, Germany; Bernstein Center Freiburg, University of FreiburgFreiburg, Germany; BrainLinks-BrainTools, Cluster of Excellence, University of FreiburgFreiburg, Germany
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Structural basis of transcobalamin recognition by human CD320 receptor. Nat Commun 2016; 7:12100. [PMID: 27411955 PMCID: PMC4947154 DOI: 10.1038/ncomms12100] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 05/27/2016] [Indexed: 12/20/2022] Open
Abstract
Cellular uptake of vitamin B12 (cobalamin) requires capture of transcobalamin (TC) from the plasma by CD320, a ubiquitous cell surface receptor of the LDLR family. Here we present the crystal structure of human holo-TC in complex with the extracellular domain of CD320, visualizing the structural basis of the TC-CD320 interaction. The observed interaction chemistry can rationalize the high affinity of CD320 for TC and lack of haptocorrin binding. The in vitro affinity and complex stability of TC-CD320 were quantitated using a solid-phase binding assay and thermostability analysis. Stable complexes with TC were also observed for the disease-causing CD320ΔE88 mutant and for the isolated LDLR-A2 domain. We also determined the structure of the TC-CD320ΔE88 complex, which revealed only minor changes compared with the wild-type complex. Finally, we demonstrate significantly reduced in vitro affinity of TC for CD320 at low pH, recapitulating the proposed ligand release during the endocytic pathway. Cellular uptake of vitamin B12 (cobalamin) requires the binding of holo-transcobalamin (TC) from plasma by CD320. Here, the authors report the structure of a complex between CD320 and TC loaded with cyanocobalamin, alongside additional functional analysis.
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Bock HH, May P. Canonical and Non-canonical Reelin Signaling. Front Cell Neurosci 2016; 10:166. [PMID: 27445693 PMCID: PMC4928174 DOI: 10.3389/fncel.2016.00166] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 06/08/2016] [Indexed: 12/11/2022] Open
Abstract
Reelin is a large secreted glycoprotein that is essential for correct neuronal positioning during neurodevelopment and is important for synaptic plasticity in the mature brain. Moreover, Reelin is expressed in many extraneuronal tissues; yet the roles of peripheral Reelin are largely unknown. In the brain, many of Reelin's functions are mediated by a molecular signaling cascade that involves two lipoprotein receptors, apolipoprotein E receptor-2 (Apoer2) and very low density-lipoprotein receptor (Vldlr), the neuronal phosphoprotein Disabled-1 (Dab1), and members of the Src family of protein tyrosine kinases as crucial elements. This core signaling pathway in turn modulates the activity of adaptor proteins and downstream protein kinase cascades, many of which target the neuronal cytoskeleton. However, additional Reelin-binding receptors have been postulated or described, either as coreceptors that are essential for the activation of the "canonical" Reelin signaling cascade involving Apoer2/Vldlr and Dab1, or as receptors that activate alternative or additional signaling pathways. Here we will give an overview of canonical and alternative Reelin signaling pathways, molecular mechanisms involved, and their potential physiological roles in the context of different biological settings.
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Affiliation(s)
- Hans H Bock
- Clinic of Gastroenterology and Hepatology, Heinrich-Heine-University Düsseldorf Düsseldorf, Germany
| | - Petra May
- Clinic of Gastroenterology and Hepatology, Heinrich-Heine-University Düsseldorf Düsseldorf, Germany
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Ranaivoson FM, von Daake S, Comoletti D. Structural Insights into Reelin Function: Present and Future. Front Cell Neurosci 2016; 10:137. [PMID: 27303268 PMCID: PMC4882317 DOI: 10.3389/fncel.2016.00137] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Accepted: 05/10/2016] [Indexed: 12/20/2022] Open
Abstract
Reelin is a neuronal glycoprotein secreted by the Cajal-Retzius cells in marginal regions of the cerebral cortex and the hippocampus where it plays important roles in the control of neuronal migration and the formation of cellular layers during brain development. This 3461 residue-long protein is composed of a signal peptide, an F-spondin-like domain, eight Reelin repeats (RR1-8), and a positively charged sequence at the C-terminus. Biochemical data indicate that the central region of Reelin binds to the low-density lipoprotein receptors apolipoprotein E receptor 2 (ApoER2) and the very-low-density lipoprotein receptor (VLDLR), leading to the phosphorylation of the intracellular adaptor protein Dab1. After secretion, Reelin is rapidly degraded in three major fragments, but the functional significance of this degradation is poorly understood. Probably due to its large mass and the complexity of its architecture, the high-resolution, three-dimensional structure of Reelin has never been determined. However, the crystal structures of some of the RRs have been solved, providing important insights into their fold and the interaction with the ApoER2 receptor. This review discusses the current findings on the structure of Reelin and its binding to the ApoER2 and VLDLR receptors, and we discuss some areas where proteomics and structural biology can help understanding Reelin function in brain development and human health.
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Affiliation(s)
- Fanomezana M Ranaivoson
- Child Health Institute of New Jersey, Robert Wood Johnson Medical School, Rutgers UniversityNew Brunswick, NJ, USA; Department of Neuroscience and Cell Biology, Robert Wood Johnson Medical School, Rutgers UniversityNew Brunswick, NJ, USA
| | - Sventja von Daake
- Child Health Institute of New Jersey, Robert Wood Johnson Medical School, Rutgers UniversityNew Brunswick, NJ, USA; Department of Neuroscience and Cell Biology, Robert Wood Johnson Medical School, Rutgers UniversityNew Brunswick, NJ, USA
| | - Davide Comoletti
- Child Health Institute of New Jersey, Robert Wood Johnson Medical School, Rutgers UniversityNew Brunswick, NJ, USA; Department of Neuroscience and Cell Biology, Robert Wood Johnson Medical School, Rutgers UniversityNew Brunswick, NJ, USA; Department of Pediatrics, Robert Wood Johnson Medical School, Rutgers UniversityNew Brunswick, NJ, USA
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40
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Lee GH, D'Arcangelo G. New Insights into Reelin-Mediated Signaling Pathways. Front Cell Neurosci 2016; 10:122. [PMID: 27242434 PMCID: PMC4860420 DOI: 10.3389/fncel.2016.00122] [Citation(s) in RCA: 103] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Accepted: 04/27/2016] [Indexed: 11/21/2022] Open
Abstract
Reelin, a multifunctional extracellular protein that is important for mammalian brain development and function, is secreted by different cell types in the prenatal or postnatal brain. The spatiotemporal regulation of Reelin expression and distribution during development relates to its multifaceted function in the brain. Prenatally Reelin controls neuronal radial migration and proper positioning in cortical layers, whereas postnatally Reelin promotes neuronal maturation, synaptic formation and plasticity. The molecular mechanisms underlying the distinct biological functions of Reelin during and after brain development involve unique and overlapping signaling pathways that are activated following Reelin binding to its cell surface receptors. Distinct Reelin ligand isoforms, such as the full-length protein or fragments generated by proteolytic cleavage differentially affect the activity of downstream signaling pathways. In this review, we discuss recent advances in our understanding of the signaling transduction pathways activated by Reelin that regulate different aspects of brain development and function. A core signaling machinery, including ApoER2/VLDLR receptors, Src/Fyn kinases, and the adaptor protein Dab1, participates in all known aspects of Reelin biology. However, distinct downstream mechanisms, such as the Crk/Rap1 pathway and cell adhesion molecules, play crucial roles in the control of neuronal migration, whereas the PI3K/Akt/mTOR pathway appears to be more important for dendrite and spine development. Finally, the NMDA receptor (NMDAR) and an unidentified receptor contribute to the activation of the MEK/Erk1/2 pathway leading to the upregulation of genes involved in synaptic plasticity and learning. This knowledge may provide new insight into neurodevelopmental or neurodegenerative disorders that are associated with Reelin dysfunction.
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Affiliation(s)
- Gum Hwa Lee
- College of Pharmacy, Chosun University Gwangju, South Korea
| | - Gabriella D'Arcangelo
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey Piscataway, NJ, USA
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41
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Lammert DB, Howell BW. RELN Mutations in Autism Spectrum Disorder. Front Cell Neurosci 2016; 10:84. [PMID: 27064498 PMCID: PMC4814460 DOI: 10.3389/fncel.2016.00084] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Accepted: 03/18/2016] [Indexed: 11/13/2022] Open
Abstract
RELN encodes a large, secreted glycoprotein integral to proper neuronal positioning during development and regulation of synaptic function postnatally. Rare, homozygous, null mutations lead to lissencephaly with cerebellar hypoplasia (LCH), accompanied by developmental delay and epilepsy. Until recently, little was known about the frequency or consequences of heterozygous mutations. Several lines of evidence from multiple studies now implicate heterozygous mutations in RELN in autism spectrum disorders (ASD). RELN maps to the AUTS1 locus on 7q22, and at this time over 40 distinct mutations have been identified that would alter the protein sequence, four of which are de novo. The RELN mutations that are most clearly consequential are those that are predicted to inactivate the signaling function of the encoded protein and those that fall in a highly conserved RXR motif found at the core of the 16 Reelin subrepeats. Despite the growing evidence of RELN dysfunction in ASD, it appears that these mutations in isolation are insufficient and that secondary genetic or environmental factors are likely required for a diagnosis.
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Affiliation(s)
- Dawn B Lammert
- Department of Neuroscience and Physiology, SUNY Upstate Medical School Syracuse, NY, USA
| | - Brian W Howell
- Department of Neuroscience and Physiology, SUNY Upstate Medical School Syracuse, NY, USA
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Sinha RK, Yang XV, Fernández JA, Xu X, Mosnier LO, Griffin JH. Apolipoprotein E Receptor 2 Mediates Activated Protein C-Induced Endothelial Akt Activation and Endothelial Barrier Stabilization. Arterioscler Thromb Vasc Biol 2016; 36:518-24. [PMID: 26800564 DOI: 10.1161/atvbaha.115.306795] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Accepted: 01/07/2016] [Indexed: 01/08/2023]
Abstract
OBJECTIVE Activated protein C (APC), a plasma serine protease, initiates cell signaling that protects endothelial cells from apoptosis and endothelial barrier disruption. Apolipoprotein E receptor 2 (ApoER2; LRP8) is a receptor known for mediating signaling initiated by reelin in neurons. ApoER2 contributes to APC-initiated signaling in monocytic U937 cells. The objective was to determine whether ApoER2 is required for APC's beneficial signaling in the endothelial cell surrogate EA.hy926 line. APPROACH AND RESULTS We used small interfering RNA and inhibitors to probe requirements for specific receptors for APC's antiapoptotic activity and for phosphorylation of disabled-1 by Src family kinases and of Akt. When small interfering RNA for ApoER2 or endothelial cell protein C receptor or protease activated receptor 1 was used, APC's antiapoptotic activity was ablated, indicating that each of these receptors was required. In EA.hy926 cells, APC induced a 2- to 3-fold increased phosphorylation of Ser473-Akt and Tyr232-disabled-1, a phosphorylation known to trigger disabled-1-mediated signaling in other cell types. Ser473-Akt phosphorylation was inhibited by ApoER2 small interfering RNA or by inhibitors of Src (PP2), phosphatidylinositol-3 kinase (LY303511), and protease activated receptor 1 (SCH79797). ApoER2 small interfering RNA blocked the ability of APC to prevent thrombin-induced endothelial barrier disruption in TransEndothelial Resistance assays. Binding studies using purified APC and purified immobilized wild-type and mutated ApoER2 ectodomains suggested that APC binding involves Lys49, Asp50, and Trp64 on the surface of the N-terminal LA1 domain of ApoER2. CONCLUSIONS ApoER2 contributes cooperatively with endothelial cell protein C receptor and protease activated receptor 1 to APC-initiated endothelial antiapoptotic and barrier protective signaling.
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Affiliation(s)
- Ranjeet K Sinha
- From the Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA
| | - Xia V Yang
- From the Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA
| | - José A Fernández
- From the Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA
| | - Xiao Xu
- From the Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA
| | - Laurent O Mosnier
- From the Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA
| | - John H Griffin
- From the Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA.
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Manoharan M, Muhammad SA, Sowdhamini R. Sequence Analysis and Evolutionary Studies of Reelin Proteins. Bioinform Biol Insights 2015; 9:187-93. [PMID: 26715843 PMCID: PMC4687978 DOI: 10.4137/bbi.s26530] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Revised: 05/19/2015] [Accepted: 05/21/2015] [Indexed: 11/05/2022] Open
Abstract
The reelin gene is conserved across many vertebrate species, including humans. The protein product of this gene plays several important roles in early brain development and regulation of neural network plasticity of a matured brain structure. With an extended structure of 3461 amino acid sequences, consisting of eight reelin repeats, the human reelin sequence stands out as an exceptional model for evolutionary studies. In this study, sequence analysis of the human reelin and its homologues and reelin sequences from 104 other species is described in detail. Interesting sequence conservation patterns of individual repeats have been highlighted. Sequence phylogeny of the reelin sequences indicates a pattern similar to the evolution of the species, thereby serving as a highly conserved family for evolutionary purposes. Multiple sequence alignment of different reelin domain repeats, derived from homologues, suggests specific functions for individual repeats and high sequence conservation across reelin repeats from different organisms, albeit with few unusual domain architectures. A three-dimensional structural model of the full-length human reelin is now available that provides clues on residues at the dimer interface.
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Affiliation(s)
- Malini Manoharan
- Tata Institute of Fundamental Research, Mumbai, India
- National Center for Biological Sciences (NCBS), Bengaluru, India
| | | | - Ramanathan Sowdhamini
- Tata Institute of Fundamental Research, Mumbai, India
- National Center for Biological Sciences (NCBS), Bengaluru, India
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44
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Gettins PGW, Dolmer K. The High Affinity Binding Site on Plasminogen Activator Inhibitor-1 (PAI-1) for the Low Density Lipoprotein Receptor-related Protein (LRP1) Is Composed of Four Basic Residues. J Biol Chem 2015; 291:800-12. [PMID: 26555266 DOI: 10.1074/jbc.m115.688820] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Indexed: 11/06/2022] Open
Abstract
Plasminogen activator inhibitor 1 (PAI-1) is a serpin inhibitor of the plasminogen activators urokinase-type plasminogen activator (uPA) and tissue plasminogen activator, which binds tightly to the clearance and signaling receptor low density lipoprotein receptor-related protein 1 (LRP1) in both proteinase-complexed and uncomplexed forms. Binding sites for PAI-1 within LRP1 have been localized to CR clusters II and IV. Within cluster II, there is a strong preference for the triple CR domain fragment CR456. Previous mutagenesis studies to identify the binding site on PAI-1 for LRP1 have given conflicting results or implied small binding contributions incompatible with the high affinity PAI-1/LRP1 interaction. Using a highly sensitive solution fluorescence assay, we have examined binding of CR456 to arginine and lysine variants of PAI-1 and definitively identified the binding site as composed of four basic residues, Lys-69, Arg-76, Lys-80, and Lys-88. These are highly conserved among mammalian PAI-1s. Individual mutations result in a 13-800-fold increase in Kd values. We present evidence that binding involves engagement of CR4 by Lys-88, CR5 by Arg-76 and Lys-80, and CR6 by Lys-69, with the strongest interactions to CR5 and CR6. Collectively, the individual binding contributions account quantitatively for the overall PAI-1/LRP1 affinity. We propose that the greater efficiency of PAI-1·uPA complex binding and clearance by LRP1, compared with PAI-1 alone, is due solely to simultaneous binding of the uPA moiety in the complex to its receptor, thereby making binding of the PAI-1 moiety to LRP1 a two-dimensional surface-localized association.
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Affiliation(s)
- Peter G W Gettins
- From the Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, Illinois 60607
| | - Klavs Dolmer
- From the Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, Illinois 60607
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Initiating protease with modular domains interacts with β-glucan recognition protein to trigger innate immune response in insects. Proc Natl Acad Sci U S A 2015; 112:13856-61. [PMID: 26504233 DOI: 10.1073/pnas.1517236112] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The autoactivation of an initiating serine protease upon binding of pattern recognition proteins to pathogen surfaces is a crucial step in eliciting insect immune responses such as the activation of Toll and prophenoloxidase pathways. However, the molecular mechanisms responsible for autoactivation of the initiating protease remains poorly understood. Here, we investigated the molecular basis for the autoactivation of hemolymph protease 14 (HP14), an initiating protease in hemolymph of Manduca sexta, upon the binding of β-1,3-glucan by its recognition protein, βGRP2. Biochemical analysis using HP14 zymogen (proHP14), βGRP2, and the recombinant proteins as truncated forms showed that the amino-terminal modular low-density lipoprotein receptor class A (LA) domains within HP14 are required for proHP14 autoactivation that is stimulated by its interaction with βGRP2. Consistent with this result, recombinant LA domains inhibit the activation of proHP14 and prophenoloxidase, likely by competing with the interaction between βGRP2 and LA domains within proHP14. Using surface plasmon resonance, we demonstrated that immobilized LA domains directly interact with βGRP2 in a calcium-dependent manner and that high-affinity interaction requires the C-terminal glucanase-like domain of βGRP2. Importantly, the affinity of LA domains for βGRP2 increases nearly 100-fold in the presence of β-1,3-glucan. Taken together, these results present the first experimental evidence to our knowledge that LA domains of an insect modular protease and glucanase-like domains of a βGRP mediate their interaction, and that this binding is essential for the protease autoactivation. Thus, our study provides important insight into the molecular basis underlying the initiation of protease cascade in insect immune responses.
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Kurasawa JH, Shestopal SA, Woodle SA, Ovanesov MV, Lee TK, Sarafanov AG. Cluster III of low-density lipoprotein receptor-related protein 1 binds activated blood coagulation factor VIII. Biochemistry 2014; 54:481-9. [PMID: 25486042 DOI: 10.1021/bi5011688] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Low-density lipoprotein receptor-related protein 1 (LRP) mediates clearance of blood coagulation factor VIII (FVIII). In LRP, FVIII binds the complement-type repeats (CRs) of clusters II and IV, which also bind a majority of other LRP ligands. No ligand is known for LRP cluster I, and only three ligands, including the LRP chaperone alpha-2 macroglobulin receptor-associated protein (RAP), bind cluster III. Using surface plasmon resonance, we found that in addition to clusters II and IV, activated FVIII (FVIIIa) binds cluster III. The specificity of this interaction was confirmed using an anti-FVIII antibody fragment, which inhibited the binding. Recombinant fragments of cluster III and its site-directed mutagenesis were used to localize the cluster's site for binding FVIIIa to CR.14-19. The interactive site of FVIIIa was localized within its A1/A3'-C1-C2 heterodimer (HDa), which is a major physiological remnant of FVIIIa. In mice, the clearance of HDa was faster than that of FVIII and prolonged in the presence of RAP, which is known to inhibit interactions of LRP with its ligands. In accordance with this, the cluster III site for RAP (CR.15-19) was found to overlap that for FVIIIa. Altogether, our findings support the involvement of LRP in FVIIIa catabolism and suggest a greater significance of the biological role of cluster III compared to that previously known.
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Affiliation(s)
- James H Kurasawa
- Center for Biologics Evaluation and Research, Food and Drug Administration , Silver Spring, Maryland 20993-0002, United States
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Mehmedbasic A, Christensen SK, Nilsson J, Rüetschi U, Gustafsen C, Poulsen ASA, Rasmussen RW, Fjorback AN, Larson G, Andersen OM. SorLA complement-type repeat domains protect the amyloid precursor protein against processing. J Biol Chem 2014; 290:3359-76. [PMID: 25525276 DOI: 10.1074/jbc.m114.619940] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
SorLA is a neuronal sorting receptor that is genetically associated with Alzheimer disease. SorLA interacts directly with the amyloid precursor protein (APP) and affects the processing of the precursor, leading to a decreased generation of the amyloid-β peptide. The SorLA complement-type repeat (CR) domains associate in vitro with APP, but the precise molecular determinants of SorLA·APP complex formation and the mechanisms responsible for the effect of binding on APP processing have not yet been elucidated. Here, we have generated protein expression constructs for SorLA devoid of the 11 CR-domains and for two SorLA mutants harboring substitutions of the fingerprint residues in the central CR-domains. We generated SH-SY5Y cell lines that stably express these SorLA variants to study the binding and processing of APP using co-immunoprecipitation and Western blotting/ELISAs, respectively. We found that the SorLA CR-cluster is essential for interaction with APP and that deletion of the CR-cluster abolishes the protection against APP processing. Mutation of identified fingerprint residues in the SorLA CR-domains leads to changes in the O-linked glycosylation of APP when expressed in SH-SY5Y cells. Our results provide novel information on the mechanisms behind the influence of SorLA activity on APP metabolism by controlling post-translational glycosylation in the Golgi, suggesting new strategies against amyloidogenesis in Alzheimer disease.
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Affiliation(s)
- Arnela Mehmedbasic
- From the Lundbeck Foundation Research Center MIND, Danish Research Institute of Translational Neuroscience Nordic-EMBL Partnership (DANDRITE), Department of Biomedicine, Aarhus University, Ole Worms Allé 3, DK-8000 AarhusC, Denmark and
| | - Sofie K Christensen
- From the Lundbeck Foundation Research Center MIND, Danish Research Institute of Translational Neuroscience Nordic-EMBL Partnership (DANDRITE), Department of Biomedicine, Aarhus University, Ole Worms Allé 3, DK-8000 AarhusC, Denmark and
| | - Jonas Nilsson
- the Department of Clinical Chemistry and Transfusion Medicine, Institute of Biomedicine, University of Gothenburg, SE-413 45 Gothenburg, Sweden
| | - Ulla Rüetschi
- the Department of Clinical Chemistry and Transfusion Medicine, Institute of Biomedicine, University of Gothenburg, SE-413 45 Gothenburg, Sweden
| | - Camilla Gustafsen
- From the Lundbeck Foundation Research Center MIND, Danish Research Institute of Translational Neuroscience Nordic-EMBL Partnership (DANDRITE), Department of Biomedicine, Aarhus University, Ole Worms Allé 3, DK-8000 AarhusC, Denmark and
| | - Annemarie Svane Aavild Poulsen
- From the Lundbeck Foundation Research Center MIND, Danish Research Institute of Translational Neuroscience Nordic-EMBL Partnership (DANDRITE), Department of Biomedicine, Aarhus University, Ole Worms Allé 3, DK-8000 AarhusC, Denmark and
| | - Rikke W Rasmussen
- From the Lundbeck Foundation Research Center MIND, Danish Research Institute of Translational Neuroscience Nordic-EMBL Partnership (DANDRITE), Department of Biomedicine, Aarhus University, Ole Worms Allé 3, DK-8000 AarhusC, Denmark and
| | - Anja N Fjorback
- From the Lundbeck Foundation Research Center MIND, Danish Research Institute of Translational Neuroscience Nordic-EMBL Partnership (DANDRITE), Department of Biomedicine, Aarhus University, Ole Worms Allé 3, DK-8000 AarhusC, Denmark and
| | - Göran Larson
- the Department of Clinical Chemistry and Transfusion Medicine, Institute of Biomedicine, University of Gothenburg, SE-413 45 Gothenburg, Sweden
| | - Olav M Andersen
- From the Lundbeck Foundation Research Center MIND, Danish Research Institute of Translational Neuroscience Nordic-EMBL Partnership (DANDRITE), Department of Biomedicine, Aarhus University, Ole Worms Allé 3, DK-8000 AarhusC, Denmark and
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Diepenhorst NA, Petrie EJ, Chen CZ, Wang A, Hossain MA, Bathgate RAD, Gooley PR. Investigation of interactions at the extracellular loops of the relaxin family peptide receptor 1 (RXFP1). J Biol Chem 2014; 289:34938-52. [PMID: 25352603 DOI: 10.1074/jbc.m114.600882] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Relaxin, an emerging pharmaceutical treatment for acute heart failure, activates the relaxin family peptide receptor (RXFP1), which is a class A G-protein-coupled receptor. In addition to the classic transmembrane (TM) domain, RXFP1 possesses a large extracellular domain consisting of 10 leucine-rich repeats and an N-terminal low density lipoprotein class A (LDLa) module. Relaxin-mediated activation of RXFP1 requires multiple coordinated interactions between the ligand and various receptor domains including a high affinity interaction involving the leucine-rich repeats and a predicted lower affinity interaction involving the extracellular loops (ELs). The LDLa is essential for signal activation; therefore the ELs/TM may additionally present an interaction site to facilitate this LDLa-mediated signaling. To overcome the many challenges of investigating relaxin and the LDLa module interactions with the ELs, we engineered the EL1 and EL2 loops onto a soluble protein scaffold, mapping specific ligand and loop interactions using nuclear magnetic resonance spectroscopy. Key EL residues were subsequently mutated in RXFP1, and changes in function and relaxin binding were assessed alongside the RXFP1 agonist ML290 to monitor the functional integrity of the TM domain of these mutant receptors. The outcomes of this work make an important contribution to understanding the mechanism of RXFP1 activation and will aid future development of small molecule RXFP1 agonists/antagonists.
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Affiliation(s)
- Natalie A Diepenhorst
- From the Florey Institute of Neuroscience and Mental Health, the Department of Biochemistry and Molecular Biology, and
| | - Emma J Petrie
- the Department of Biochemistry and Molecular Biology, and
| | - Catherine Z Chen
- the National Center for Advancing Translational Sciences, Division of Preclinical Innovation, National Institutes of Health, Rockville, Maryland 20850
| | - Amy Wang
- the National Center for Advancing Translational Sciences, Division of Preclinical Innovation, National Institutes of Health, Rockville, Maryland 20850
| | - Mohammed Akhter Hossain
- From the Florey Institute of Neuroscience and Mental Health, the School of Chemistry, University of Melbourne, Parkville, Victoria 3010, Australia and
| | - Ross A D Bathgate
- From the Florey Institute of Neuroscience and Mental Health, the Department of Biochemistry and Molecular Biology, and
| | - Paul R Gooley
- the Department of Biochemistry and Molecular Biology, and
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Kong RCK, Bathgate RAD, Bruell S, Wade JD, Gooley PR, Petrie EJ. Mapping Key Regions of the RXFP2 Low-Density Lipoprotein Class-A Module That Are Involved in Signal Activation. Biochemistry 2014; 53:4537-48. [DOI: 10.1021/bi500797d] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Roy C. K. Kong
- Department of Biochemistry and Molecular Biology, The Bio21 Molecular
Science and Biotechnology Institute, ‡Florey Institute of Neuroscience
and Mental Health, and §School of Chemistry, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Ross A. D. Bathgate
- Department of Biochemistry and Molecular Biology, The Bio21 Molecular
Science and Biotechnology Institute, ‡Florey Institute of Neuroscience
and Mental Health, and §School of Chemistry, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Shoni Bruell
- Department of Biochemistry and Molecular Biology, The Bio21 Molecular
Science and Biotechnology Institute, ‡Florey Institute of Neuroscience
and Mental Health, and §School of Chemistry, University of Melbourne, Parkville, Victoria 3010, Australia
| | - John D. Wade
- Department of Biochemistry and Molecular Biology, The Bio21 Molecular
Science and Biotechnology Institute, ‡Florey Institute of Neuroscience
and Mental Health, and §School of Chemistry, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Paul R. Gooley
- Department of Biochemistry and Molecular Biology, The Bio21 Molecular
Science and Biotechnology Institute, ‡Florey Institute of Neuroscience
and Mental Health, and §School of Chemistry, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Emma J. Petrie
- Department of Biochemistry and Molecular Biology, The Bio21 Molecular
Science and Biotechnology Institute, ‡Florey Institute of Neuroscience
and Mental Health, and §School of Chemistry, University of Melbourne, Parkville, Victoria 3010, Australia
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50
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Extracellular proteolysis of reelin by tissue plasminogen activator following synaptic potentiation. Neuroscience 2014; 274:299-307. [PMID: 24892761 DOI: 10.1016/j.neuroscience.2014.05.046] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Accepted: 05/21/2014] [Indexed: 01/19/2023]
Abstract
The secreted glycoprotein reelin plays an indispensable role in neuronal migration during development and in regulating adult synaptic functions. The upstream mechanisms responsible for initiating and regulating the duration and magnitude of reelin signaling are largely unknown. Here we report that reelin is cleaved between EGF-like repeats 6-7 (R6-7) by tissue plasminogen activator (tPA) under cell-free conditions. No changes were detected in the level of reelin and its fragments in the brains of tPA knockouts, implying that other unknown proteases are responsible for generating reelin fragments found constitutively in the adult brain. Induction of NMDAR-independent long-term potentiation with the potassium channel blocker tetraethylammonium chloride (TEA-Cl) led to a specific up-regulation of reelin processing at R6-7 in wild-type mice. In contrast, no changes in reelin expression and processing were observed in tPA knockouts following TEA-Cl treatment. These results demonstrate that synaptic potentiation results in tPA-dependent reelin processing and suggest that extracellular proteolysis of reelin may regulate reelin signaling in the adult brain.
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