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Klein M, Failla AV, Hermey G. Internally tagged Vps10p-domain receptors reveal uptake of the neurotrophin BDNF. J Biol Chem 2023; 299:105216. [PMID: 37660918 PMCID: PMC10540051 DOI: 10.1016/j.jbc.2023.105216] [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: 07/10/2023] [Revised: 08/14/2023] [Accepted: 08/18/2023] [Indexed: 09/05/2023] Open
Abstract
The Vps10p-domain (Vps10p-D) receptor family consists of Sortilin, SorLA, SorCS1, SorCS2, and SorCS3. They mediate internalization and intracellular sorting of specific cargo in various cell types, but underlying molecular determinants are incompletely understood. Deciphering the dynamic intracellular itineraries of Vps10p-D receptors is crucial for understanding their role in physiological and cytopathological processes. However, studying their spatial and temporal dynamics by live imaging has been challenging so far, as terminal tagging with fluorophores presumably impedes several of their protein interactions and thus functions. Here, we addressed the lack of appropriate tools and developed functional versions of all family members internally tagged in their ectodomains. We predict folding of the newly designed receptors by bioinformatics and show their exit from the endoplasmic reticulum. We examined their subcellular localization in immortalized cells and primary cultured neurons by immunocytochemistry and live imaging. This was, as far as known, identical to that of wt counterparts. We observed homodimerization of fluorophore-tagged SorCS2 by coimmunoprecipitation and fluorescence lifetime imaging, suggesting functional leucine-rich domains. Through ligand uptake experiments, live imaging and fluorescence lifetime imaging, we show for the first time that all Vps10p-D receptors interact with the neurotrophin brain-derived neurotrophic factor and mediate its uptake, indicating functionality of the Vps10p-Ds. In summary, we developed versions of all Vps10p-D receptors, with internal fluorophore tags that preserve several functions of the cytoplasmic and extracellular domains. These newly developed fluorophore-tagged receptors are likely to serve as powerful functional tools for accurate live studies of the individual cellular functions of Vps10p-D receptors.
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Affiliation(s)
- Marcel Klein
- Institute for Molecular and Cellular Cognition, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
| | | | - Guido Hermey
- Institute for Molecular and Cellular Cognition, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
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2
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Febbraro F, Andersen HHB, Kitt MM, Willnow TE. Spatially and temporally distinct patterns of expression for VPS10P domain receptors in human cerebral organoids. Front Cell Dev Biol 2023; 11:1229584. [PMID: 37842085 PMCID: PMC10570844 DOI: 10.3389/fcell.2023.1229584] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 08/28/2023] [Indexed: 10/17/2023] Open
Abstract
Vacuolar protein sorting 10 protein (VPS10P) domain receptors are a unique class of intracellular sorting receptors that emerge as major risk factors associated with psychiatric and neurodegenerative diseases, including bipolar disorders, autism, schizophrenia, as well as Alzheimer's disease and frontotemporal dementia. Yet, the lack of suitable experimental models to study receptor functions in the human brain has hampered elucidation of receptor actions in brain disease. Here, we have adapted protocols using human cerebral organoids to the detailed characterization of VPS10P domain receptor expression during neural development and differentiation, including single-cell RNA sequencing. Our studies uncovered spatial and temporal patterns of expression unique to individual receptor species in the human brain. While SORL1 expression is abundant in stem cells and SORCS1 peaks in neural progenitors at onset of neurogenesis, SORT1 and SORCS2 show increasing expression with maturation of neuronal and non-neuronal cell types, arguing for distinct functions in development versus the adult brain. In neurons, subcellular localization also distinguishes between types of receptor species, either mainly localized to the cell soma (SORL1 and SORT1) or also to neuronal projections (SORCS1 and SORCS2), suggesting divergent functions in protein sorting between Golgi and the endo-lysosomal system or along axonal and dendritic tracks. Taken together, our findings provide an important resource on temporal, spatial, and subcellular patterns of VPS10P domain receptor expression in cerebral organoids for further elucidation of receptor (dys) functions causative of behavioral and cognitive defects of the human brain.
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Affiliation(s)
- Fabia Febbraro
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | | | - Meagan M. Kitt
- Max Delbrueck Center for Molecular Medicine, Charité—Universitätsmedizin Berlin, Berlin, Germany
| | - Thomas E. Willnow
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
- Max Delbrueck Center for Molecular Medicine, Charité—Universitätsmedizin Berlin, Berlin, Germany
- Max Delbrueck Center for Molecular Medicine, Berlin, Germany
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3
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Lee AK, Yi N, Khaled H, Feller B, Takahashi H. SorCS1 inhibits amyloid-β binding to neurexin and rescues amyloid-β-induced synaptic pathology. Life Sci Alliance 2023; 6:e202201681. [PMID: 36697254 PMCID: PMC9880023 DOI: 10.26508/lsa.202201681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 01/13/2023] [Accepted: 01/16/2023] [Indexed: 01/27/2023] Open
Abstract
Amyloid-β oligomers (AβOs), toxic peptide aggregates found in Alzheimer's disease, cause synapse pathology. AβOs interact with neurexins (NRXs), key synaptic organizers, and this interaction dampens normal trafficking and function of NRXs. Axonal trafficking of NRX is in part regulated by its interaction with SorCS1, a protein sorting receptor, but the impact of SorCS1 regulation of NRXs in Aβ pathology was previously unstudied. Here, we show competition between the SorCS1 ectodomain and AβOs for β-NRX binding and rescue effects of the SorCS1b isoform on AβO-induced synaptic pathology. Like AβOs, the SorCS1 ectodomain binds to NRX1β through the histidine-rich domain of NRX1β, and the SorCS1 ectodomain and AβOs compete for NRX1β binding. In cultured hippocampal neurons, SorCS1b colocalizes with NRX1β on the axon surface, and axonal expression of SorCS1b rescues AβO-induced impairment of NRX-mediated presynaptic organization and presynaptic vesicle recycling and AβO-induced structural defects in excitatory synapses. Thus, our data suggest a role for SorCS1 in the rescue of AβO-induced NRX dysfunction and synaptic pathology, providing the basis for a novel potential therapeutic strategy for Alzheimer's disease.
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Affiliation(s)
- Alfred Kihoon Lee
- Synapse Development and Plasticity Research Unit, Institut de Recherches Cliniques de Montréal, Montreal, Canada
- Integrated Program in Neuroscience, McGill University, Montreal, Canada
| | - Nayoung Yi
- Synapse Development and Plasticity Research Unit, Institut de Recherches Cliniques de Montréal, Montreal, Canada
- Department of Medicine, Université de Montréal, Montreal, Canada
| | - Husam Khaled
- Synapse Development and Plasticity Research Unit, Institut de Recherches Cliniques de Montréal, Montreal, Canada
- Department of Medicine, Université de Montréal, Montreal, Canada
| | - Benjamin Feller
- Synapse Development and Plasticity Research Unit, Institut de Recherches Cliniques de Montréal, Montreal, Canada
- Department of Medicine, Université de Montréal, Montreal, Canada
| | - Hideto Takahashi
- Synapse Development and Plasticity Research Unit, Institut de Recherches Cliniques de Montréal, Montreal, Canada
- Integrated Program in Neuroscience, McGill University, Montreal, Canada
- Department of Medicine, Université de Montréal, Montreal, Canada
- Division of Experimental Medicine, McGill University, Montreal, Canada
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4
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Salasova A, Monti G, Andersen OM, Nykjaer A. Finding memo: versatile interactions of the VPS10p-Domain receptors in Alzheimer’s disease. Mol Neurodegener 2022; 17:74. [PMID: 36397124 PMCID: PMC9673319 DOI: 10.1186/s13024-022-00576-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2022] [Accepted: 10/17/2022] [Indexed: 11/19/2022] Open
Abstract
The family of VPS10p-Domain (D) receptors comprises five members named SorLA, Sortilin, SorCS1, SorCS2 and SorCS3. While their physiological roles remain incompletely resolved, they have been recognized for their signaling engagements and trafficking abilities, navigating a number of molecules between endosome, Golgi compartments, and the cell surface. Strikingly, recent studies connected all the VPS10p-D receptors to Alzheimer’s disease (AD) development. In addition, they have been also associated with diseases comorbid with AD such as diabetes mellitus and major depressive disorder. This systematic review elaborates on genetic, functional, and mechanistic insights into how dysfunction in VPS10p-D receptors may contribute to AD etiology, AD onset diversity, and AD comorbidities. Starting with their functions in controlling cellular trafficking of amyloid precursor protein and the metabolism of the amyloid beta peptide, we present and exemplify how these receptors, despite being structurally similar, regulate various and distinct cellular events involved in AD. This includes a plethora of signaling crosstalks that impact on neuronal survival, neuronal wiring, neuronal polarity, and synaptic plasticity. Signaling activities of the VPS10p-D receptors are especially linked, but not limited to, the regulation of neuronal fitness and apoptosis via their physical interaction with pro- and mature neurotrophins and their receptors. By compiling the functional versatility of VPS10p-D receptors and their interactions with AD-related pathways, we aim to further propel the AD research towards VPS10p-D receptor family, knowledge that may lead to new diagnostic markers and therapeutic strategies for AD patients.
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Binkle L, Klein M, Borgmeyer U, Kuhl D, Hermey G. The adaptor protein PICK1 targets the sorting receptor SorLA. Mol Brain 2022; 15:18. [PMID: 35183222 PMCID: PMC8858569 DOI: 10.1186/s13041-022-00903-0] [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: 10/06/2021] [Accepted: 02/07/2022] [Indexed: 11/26/2022] Open
Abstract
SorLA is a member of the Vps10p-domain (Vps10p-D) receptor family of type-I transmembrane proteins conveying neuronal endosomal sorting. The extracellular/luminal moiety of SorLA has a unique mosaic domain composition and interacts with a large number of different and partially unrelated ligands, including the amyloid precursor protein as well as amyloid-β. Several studies support a strong association of SorLA with sporadic and familial forms of Alzheimer’s disease (AD). Although SorLA seems to be an important factor in AD, the large number of different ligands suggests a role as a neuronal multifunctional receptor with additional intracellular sorting capacities. Therefore, understanding the determinants of SorLA’s subcellular targeting might be pertinent for understanding neuronal endosomal sorting mechanisms in general. A number of cytosolic adaptor proteins have already been demonstrated to determine intracellular trafficking of SorLA. Most of these adaptors and several ligands of the extracellular/luminal moiety are shared with the Vps10p-D receptor Sortilin. Although SorLA and Sortilin show both a predominant intracellular and endosomal localization, they are targeted to different endosomal compartments. Thus, independent adaptor proteins may convey their differential endosomal targeting. Here, we hypothesized that Sortilin and SorLA interact with the cytosolic adaptors PSD95 and PICK1 which have been shown to bind the Vps10p-D receptor SorCS3. We observed only an interaction for SorLA and PICK1 in mammalian-two-hybrid, pull-down and cellular recruitment experiments. We demonstrate by mutational analysis that the C-terminal minimal PDZ domain binding motif VIA of SorLA mediates the interaction. Moreover, we show co-localization of SorLA and PICK1 at vesicular structures in primary neurons. Although the physiological role of the interaction between PICK1 and SorLA remains unsolved, our study suggests that PICK1 partakes in regulating SorLA’s intracellular itinerary.
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6
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VPS10P Domain Receptors: Sorting Out Brain Health and Disease. Trends Neurosci 2020; 43:870-885. [DOI: 10.1016/j.tins.2020.08.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 07/23/2020] [Accepted: 08/11/2020] [Indexed: 12/13/2022]
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Type 2 diabetes-associated single nucleotide polymorphism in Sorcs1 gene results in alternative processing of the Sorcs1 protein in INS1 β-cells. Sci Rep 2019; 9:19466. [PMID: 31857633 PMCID: PMC6923373 DOI: 10.1038/s41598-019-55873-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Accepted: 12/03/2019] [Indexed: 01/20/2023] Open
Abstract
A threonine-to-Isoleucine (Thr52Ile) mutation within the pro-domain of the Sorcs1 gene was positionally cloned as the gene underlying a quantitative trait locus that affects fasting insulin levels in mice. In humans, genome-wide association studies and linkage studies have shown that SORCS1 is associated with diabetes and all of diabetes complications. We have recently shown that deletion of Sorcs1 in mice made obese with the leptinob mutation results in diabetes and an insulin granule stability defect. This present study investigates the functional consequence of the Sorcs1 Thr52Ile mutation in the rat INS1 β-cell line expressing either the wildtype or mutant Sorcs1 allele. We find that Sorcs1 Thr52Ile mutation is associated with increased basal insulin secretion, reduced glucose-stimulated insulin secretion and decreased insulin content in INS1 cells. Moreover, expression of Thr52Ile causes differential processing of the Sorcs1 protein resulting in the formation of an additional 90 kDa mutant form of the protein. The mutant form of the protein is localised to the ER, retains its pro-domain, and concurrently reduces expression of the functional mature 130 kDa Sorcs1 protein. These findings provide a mechanistic clue to why this specific allelic variation in Sorcs1 was associated with reduced insulin levels and type 2 diabetes.
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Bajaj L, Lotfi P, Pal R, di Ronza A, Sharma J, Sardiello M. Lysosome biogenesis in health and disease. J Neurochem 2019; 148:573-589. [PMID: 30092616 PMCID: PMC6368902 DOI: 10.1111/jnc.14564] [Citation(s) in RCA: 86] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 08/01/2018] [Accepted: 08/03/2018] [Indexed: 01/01/2023]
Abstract
This review focuses on the pathways that regulate lysosome biogenesis and that are implicated in numerous degenerative storage diseases, including lysosomal storage disorders and late-onset neurodegenerative diseases. Lysosomal proteins are synthesized in the endoplasmic reticulum and trafficked to the endolysosomal system through the secretory route. Several receptors have been characterized that execute post-Golgi trafficking of lysosomal proteins. Some of them recognize their cargo proteins based on specific amino acid signatures, others based on a particular glycan modification that is exclusively found on lysosomal proteins. Nearly all receptors serving lysosome biogenesis are under the transcriptional control of transcription factor EB (TFEB), a master regulator of the lysosomal system. TFEB coordinates the expression of lysosomal hydrolases, lysosomal membrane proteins, and autophagy proteins in response to pathways sensing lysosomal stress and the nutritional conditions of the cell among other stimuli. TFEB is primed for activation in lysosomal storage disorders but surprisingly its function is impaired in some late-onset neurodegenerative storage diseases like Alzheimer's and Parkinson's, because of specific detrimental interactions that limit TFEB expression or activation. Thus, disrupted TFEB function presumably plays a role in the pathogenesis of these diseases. Multiple studies in animal models of degenerative storage diseases have shown that exogenous expression of TFEB and pharmacological activation of endogenous TFEB attenuate disease phenotypes. These results highlight TFEB-mediated enhancement of lysosomal biogenesis and function as a candidate strategy to counteract the progression of these diseases. This article is part of the Special Issue "Lysosomal Storage Disorders".
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Affiliation(s)
- Lakshya Bajaj
- Department of Molecular and Human Genetics, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, TX 77030 USA
| | - Parisa Lotfi
- Department of Molecular and Human Genetics, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, TX 77030 USA
| | - Rituraj Pal
- Department of Molecular and Human Genetics, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, TX 77030 USA
| | - Alberto di Ronza
- Department of Molecular and Human Genetics, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, TX 77030 USA
| | - Jaiprakash Sharma
- Department of Molecular and Human Genetics, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, TX 77030 USA
| | - Marco Sardiello
- Department of Molecular and Human Genetics, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, TX 77030 USA
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9
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Blechingberg J, Poulsen ASA, Kjølby M, Monti G, Allen M, Ivarsen AK, Lincoln SJ, Thotakura G, Vægter CB, Ertekin-Taner N, Nykjær A, Andersen OM. An alternative transcript of the Alzheimer's disease risk gene SORL1 encodes a truncated receptor. Neurobiol Aging 2018; 71:266.e11-266.e24. [PMID: 30078640 DOI: 10.1016/j.neurobiolaging.2018.06.021] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Revised: 06/03/2018] [Accepted: 06/18/2018] [Indexed: 10/28/2022]
Abstract
SORL1 encodes a 250-kDa protein named sorLA, a functional sorting receptor for the amyloid precursor protein (APP). Several single nucleotide polymorphisms of the gene SORL1, encoding sorLA, are genetically associated with Alzheimer's disease (AD). In the existing literature, SORL1 is insufficiently described at the transcriptional level, and there is very limited amount of functional data defining different transcripts. We have characterized a SORL1 transcript containing a novel exon 30B. The transcript is expressed in most brain regions with highest expression in the temporal lobe and hippocampus. Exon 30B is spliced to exon 31, leading to a mature transcript that encodes an 829 amino acid sorLA receptor. This receptor variant lacks the binding site for APP and is unlikely to function in APP sorting. This transcript is expressed in equal amounts in the cerebellum from AD and non-AD individuals. Our data describe a transcript that encodes a truncated sorLA receptor, suggesting novel neuronal functions for sorLA and that alternative transcription provides a mechanism for SORL1 activity regulation.
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Affiliation(s)
- Jenny Blechingberg
- Danish Research Institute of Translational Neuroscience (DANDRITE) Nordic-EMBL Partnership, Aarhus, Denmark
| | | | - Mads Kjølby
- Danish Research Institute of Translational Neuroscience (DANDRITE) Nordic-EMBL Partnership, Aarhus, Denmark; Danish Diabetes Academy, Novo Nordisk Foundation, Aarhus University, Aarhus, Denmark
| | - Giulia Monti
- Danish Research Institute of Translational Neuroscience (DANDRITE) Nordic-EMBL Partnership, Aarhus, Denmark
| | - Mariet Allen
- Department of Neuroscience, Mayo Clinic, FL, USA
| | - Anne Kathrine Ivarsen
- Danish Research Institute of Translational Neuroscience (DANDRITE) Nordic-EMBL Partnership, Aarhus, Denmark
| | | | | | - Christian B Vægter
- Danish Research Institute of Translational Neuroscience (DANDRITE) Nordic-EMBL Partnership, Aarhus, Denmark
| | | | - Anders Nykjær
- Danish Research Institute of Translational Neuroscience (DANDRITE) Nordic-EMBL Partnership, Aarhus, Denmark; The Lundbeck Foundation Research Center MIND, Aarhus, Denmark; The Danish Research Foundation Center PROMEMO, Department of Biomedicine, Aarhus, Denmark; Department of Neurosurgery, Aarhus University Hospital, Aarhus, Denmark
| | - Olav M Andersen
- Danish Research Institute of Translational Neuroscience (DANDRITE) Nordic-EMBL Partnership, Aarhus, Denmark.
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Trafficking in Alzheimer's Disease: Modulation of APP Transport and Processing by the Transmembrane Proteins LRP1, SorLA, SorCS1c, Sortilin, and Calsyntenin. Mol Neurobiol 2017; 55:5809-5829. [PMID: 29079999 DOI: 10.1007/s12035-017-0806-x] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 10/17/2017] [Indexed: 12/11/2022]
Abstract
The amyloid precursor protein (APP), one key player in Alzheimer's disease (AD), is extensively processed by different proteases. This leads to the generation of diverging fragments including the amyloid β (Aβ) peptide, which accumulates in brains of AD patients. Subcellular trafficking of APP is an important aspect for its proteolytic conversion, since the various secretases which cleave APP are located in different cellular compartments. As a consequence, altered subcellular targeting of APP is thought to directly affect the degree to which Aβ is generated. The mechanisms underlying intracellular APP transport are critical to understand AD pathogenesis and can serve as a target for future pharmacological interventions. In the recent years, a number of APP interacting proteins were identified which are implicated in sorting of APP, thereby influencing APP processing at different angles of the secretory or endocytic pathway. This review provides an update on the proteolytic processing of APP and the interplay of the transmembrane proteins low-density lipoprotein receptor-related protein 1, sortilin-receptor with A-type repeats, SorCS1c, sortilin, and calsyntenin. We discuss the specific interactions with APP, the capacity to modulate the intracellular itinerary and the proteolytic conversion of APP, a possible involvement in the clearance of Aβ, and the implications of these transmembrane proteins in AD and other neurodegenerative diseases.
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Campbell C, Beug S, Nickerson PEB, Peng J, Mazerolle C, Bassett EA, Ringuette R, Jama FA, Morales C, Christ A, Wallace VA. Sortilin regulates sorting and secretion of Sonic hedgehog. J Cell Sci 2016; 129:3832-3844. [PMID: 27632999 DOI: 10.1242/jcs.183541] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Accepted: 08/26/2016] [Indexed: 01/03/2023] Open
Abstract
Sonic Hedgehog (Shh) is a secreted morphogen that is an essential regulator of patterning and growth. The Shh full-length protein undergoes autocleavage in the endoplasmic reticulum to generate the biologically active N-terminal fragment (ShhN), which is destined for secretion. We identified sortilin (Sort1), a member of the VPS10P-domain receptor family, as a new Shh trafficking receptor. We demonstrate that Sort-Shh interact by performing coimmunoprecipitation and proximity ligation assays in transfected cells and that they colocalize at the Golgi. Sort1 overexpression causes re-distribution of ShhN and, to a lesser extent, of full-length Shh to the Golgi and reduces Shh secretion. We show loss of Sort1 can partially rescue Hedgehog-associated patterning defects in a mouse model that is deficient in Shh processing, and we show that Sort1 levels negatively regulate anterograde Shh transport in axons in vitro and Hedgehog-dependent axon-glial interactions in vivo Taken together, we conclude that Shh and Sort1 can interact at the level of the Golgi and that Sort1 directs Shh away from the pathways that promote its secretion.
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Affiliation(s)
- Charles Campbell
- Regenerative Medicine Program, Ottawa Hospital Research Institute, 501 Smyth Road, Ottawa, Ontario, Canada K1H 8L6 Department of Cellular and Molecular Medicine, University of Ottawa, 451 Smyth Road, Ottawa, Ontario, Canada K1H 8M5
| | - Shawn Beug
- Regenerative Medicine Program, Ottawa Hospital Research Institute, 501 Smyth Road, Ottawa, Ontario, Canada K1H 8L6 Department of Biochemistry, Microbiology, and Immunology, University of Ottawa, 451 Smyth Road, Ottawa, Ontario, Canada K1H 8M5
| | - Philip E B Nickerson
- Vision Science Division, Krembil Research Institute, University Health Network and Department of Ophthalmology and Vision Sciences, University of Toronto, 60 Leonard Street, Toronto ON M5T 2S8
| | - Jimmy Peng
- Department of Biology, McGill University, 1205 Ave Docteur Penfield Room W4/8, Montreal, Quebec, Canada H3A 1B1 Institut de recherches cliniques de Montréal (IRCM), 110 Avenue des Pins Ouest, Montréal, Quebec, Canada H2W 1R7
| | - Chantal Mazerolle
- Regenerative Medicine Program, Ottawa Hospital Research Institute, 501 Smyth Road, Ottawa, Ontario, Canada K1H 8L6
| | - Erin A Bassett
- Regenerative Medicine Program, Ottawa Hospital Research Institute, 501 Smyth Road, Ottawa, Ontario, Canada K1H 8L6
| | - Randy Ringuette
- Regenerative Medicine Program, Ottawa Hospital Research Institute, 501 Smyth Road, Ottawa, Ontario, Canada K1H 8L6 Department of Cellular and Molecular Medicine, University of Ottawa, 451 Smyth Road, Ottawa, Ontario, Canada K1H 8M5
| | - Fadumo A Jama
- Regenerative Medicine Program, Ottawa Hospital Research Institute, 501 Smyth Road, Ottawa, Ontario, Canada K1H 8L6 Department of Biochemistry, Microbiology, and Immunology, University of Ottawa, 451 Smyth Road, Ottawa, Ontario, Canada K1H 8M5
| | - Carlos Morales
- Department of Anatomy and Cell Biology, McGill University, 3640 Rue University, Montréal, Quebec, Canada H3A 0C7
| | - Annabel Christ
- Max-Delbrück-Center for Molecular Medicine, Robert-Rössle-Str. 10, 13125 Berlin, Germany
| | - Valerie A Wallace
- Regenerative Medicine Program, Ottawa Hospital Research Institute, 501 Smyth Road, Ottawa, Ontario, Canada K1H 8L6 Department of Biochemistry, Microbiology, and Immunology, University of Ottawa, 451 Smyth Road, Ottawa, Ontario, Canada K1H 8M5 Vision Science Division, Krembil Research Institute, University Health Network and Department of Ophthalmology and Vision Sciences, University of Toronto, 60 Leonard Street, Toronto ON M5T 2S8
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Hermey G, Schmidt N, Bluhm B, Mensching D, Ostermann K, Rupp C, Kuhl D, Kins S. SorCS1 variants and amyloid precursor protein (APP) are co-transported in neurons but only SorCS1c modulates anterograde APP transport. J Neurochem 2015; 135:60-75. [PMID: 26119586 DOI: 10.1111/jnc.13221] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Revised: 05/06/2015] [Accepted: 06/22/2015] [Indexed: 12/13/2022]
Abstract
Processing of amyloid precursor protein (APP) into amyloid-β peptide (Aβ) is crucial for the development of Alzheimer's disease (AD). Because this processing is highly dependent on its intracellular itinerary, altered subcellular targeting of APP is thought to directly affect the degree to which Aβ is generated. The sorting receptor SorCS1 has been genetically linked to AD, but the underlying molecular mechanisms are poorly understood. We analyze two SorCS1 variants; one, SorCS1c, conveys internalization of surface-bound ligands whereas the other, SorCS1b, does not. In agreement with previous studies, we demonstrate co-immunoprecipitation and co-localization of both SorCS1 variants with APP. Our results suggest that SorCS1c and APP are internalized independently, although they mostly share a common post-endocytic pathway. We introduce functional Venus-tagged constructs to study SorCS1b and SorCS1c in living cells. Both variants are transported by fast anterograde axonal transport machinery and about 30% of anterograde APP-positive transport vesicles contain SorCS1. Co-expression of SorCS1b caused no change of APP transport kinetics, but SorCS1c reduced the anterograde transport rate of APP and increased the number of APP-positive stationary vesicles. These data suggest that SorCS1 and APP share trafficking pathways and that SorCS1c can retain APP from insertion into anterograde transport vesicles. Altered APP trafficking is thought to modulate its processing. SorCS1 has been suggested to function in APP trafficking. We analyzed if the two SorCS1 variants, SorCS1b and SorCS1c, tie APP to the cell surface or modify its internalization and intracellular targeting. We observed co-localization and vesicular co-transport of APP and SorCS1, but independent internalization and sorting through a common post-endocytic pathway. Co-expression of one variant, SorCS1c, reduced anterograde APP transport. These data demonstrate that SorCS1 and APP share trafficking pathways and that SorCS1c can retain APP from insertion into anterograde transport vesicles.
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Affiliation(s)
- Guido Hermey
- Institute for Molecular and Cellular Cognition, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Nadine Schmidt
- Division of Human Biology and Human Genetics, University of Kaiserslautern, Kaiserslautern, Germany
| | - Björn Bluhm
- Institute for Molecular and Cellular Cognition, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Daniel Mensching
- Institute for Molecular and Cellular Cognition, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Kristina Ostermann
- Division of Human Biology and Human Genetics, University of Kaiserslautern, Kaiserslautern, Germany
| | - Carsten Rupp
- Division of Human Biology and Human Genetics, University of Kaiserslautern, Kaiserslautern, Germany
| | - Dietmar Kuhl
- Institute for Molecular and Cellular Cognition, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Stefan Kins
- Division of Human Biology and Human Genetics, University of Kaiserslautern, Kaiserslautern, Germany
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Darling JE, Zhao F, Loftus RJ, Patton LM, Gibbs RA, Hougland JL. Structure–Activity Analysis of Human Ghrelin O-Acyltransferase Reveals Chemical Determinants of Ghrelin Selectivity and Acyl Group Recognition. Biochemistry 2015; 54:1100-10. [DOI: 10.1021/bi5010359] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Joseph E. Darling
- Department
of Chemistry, Syracuse University, Syracuse, New York 13244, United States
| | - Feifei Zhao
- Department
of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, Indiana 47907, United States
| | - Rosemary J. Loftus
- Department
of Chemistry, Syracuse University, Syracuse, New York 13244, United States
| | - Leslie M. Patton
- Department
of Chemistry, Syracuse University, Syracuse, New York 13244, United States
| | - Richard A. Gibbs
- Department
of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, Indiana 47907, United States
| | - James L. Hougland
- Department
of Chemistry, Syracuse University, Syracuse, New York 13244, United States
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14
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Kebede MA, Oler AT, Gregg T, Balloon AJ, Johnson A, Mitok K, Rabaglia M, Schueler K, Stapleton D, Thorstenson C, Wrighton L, Floyd BJ, Richards O, Raines S, Eliceiri K, Seidah NG, Rhodes C, Keller MP, Coon JL, Audhya A, Attie AD. SORCS1 is necessary for normal insulin secretory granule biogenesis in metabolically stressed β cells. J Clin Invest 2014; 124:4240-56. [PMID: 25157818 DOI: 10.1172/jci74072] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Accepted: 07/14/2014] [Indexed: 01/21/2023] Open
Abstract
We previously positionally cloned Sorcs1 as a diabetes quantitative trait locus. Sorcs1 belongs to the Vacuolar protein sorting-10 (Vps10) gene family. In yeast, Vps10 transports enzymes from the trans-Golgi network (TGN) to the vacuole. Whole-body Sorcs1 KO mice, when made obese with the leptin(ob) mutation (ob/ob), developed diabetes. β Cells from these mice had a severe deficiency of secretory granules (SGs) and insulin. Interestingly, a single secretagogue challenge failed to consistently elicit an insulin secretory dysfunction. However, multiple challenges of the Sorcs1 KO ob/ob islets consistently revealed an insulin secretion defect. The luminal domain of SORCS1 (Lum-Sorcs1), when expressed in a β cell line, acted as a dominant-negative, leading to SG and insulin deficiency. Using syncollin-dsRed5TIMER adenovirus, we found that the loss of Sorcs1 function greatly impairs the rapid replenishment of SGs following secretagogue challenge. Chronic exposure of islets from lean Sorcs1 KO mice to high glucose and palmitate depleted insulin content and evoked an insulin secretion defect. Thus, in metabolically stressed mice, Sorcs1 is important for SG replenishment, and under chronic challenge by insulin secretagogues, loss of Sorcs1 leads to diabetes. Overexpression of full-length SORCS1 led to a 2-fold increase in SG content, suggesting that SORCS1 is sufficient to promote SG biogenesis.
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Abstract
Sortilin and sorCS1 [sortilin-related Vps10p (vacuolar protein sorting/targeting protein 10) domain-containing receptor 1], both members of the Vps10p-D (Vps10p-domain) receptor family, are synthesized as precursor proteins and are converted into their mature form by enzymatic cleavage of a short N-terminal propeptide. SorCS1 does not bind its propeptide, but sortilin is able to bind not just its own propeptide, but also that of sorCS1. In the present study we show that the propeptide region of sorCS1 contains two separate sites for binding to sortilin and that only one of these sites is removed from human (as opposed to mouse) sorCS1 during processing. This leaves mature human sorCS1 with a sortilin-binding N-terminus, which allows formation of a complex between the two receptors in solution and on cell membranes. Furthermore, we find that the interaction with sorCS1 has a pronounced effect on sortilin's ability to mediate the cellular uptake of alternative ligands, and to hamper its facilitation of CNTF (ciliary neutrophic factor) signalling and the induction of phosphorylated STAT3 (signal transducer and activator of transcription 3). Thus the present study reveals a novel regulatory mechanism and suggest an entirely new role for sorCS1 as a modulator of sortilin function.
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Abstract
The sortilin family of Vps10p-domain receptors includes sortilin, SorLA, and SorCS1-3. These type-I transmembrane receptors predominate in distinct neuronal tissues, but expression is also present in certain specialized non-neuronal cell populations including hepatocytes and cells of the immune system. The biology of sortilins is complex as they participate in both cell signaling and in intracellular protein sorting. Sortilins function physiologically in signaling by pro- and mature neurotrophins in neuronal viability and functionality. Recent genome-wide association studies have linked members to neurological disorders such as Alzheimer's disease and bipolar disorder and outside the nervous system to development of coronary artery disease and type-2 diabetes. Particularly well described are the receptor functions in neuronal signaling by pro- (proNT) and mature (NT) neurotrophins and in the processing/metabolism of amyloid precursor protein (APP).
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Affiliation(s)
- S Glerup
- Danish Research Institute of Translational Neuroscience DANDRITE, Nordic EMBL Partnership, and The Lundbeck Foundation Research Center MIND, Department of Biomedicine, University of Aarhus, Ole Worms Allé 3, 8000, Aarhus C, Denmark
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17
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Lazar J, O'Meara CC, Sarkis AB, Prisco SZ, Xu H, Fox CS, Chen MH, Broeckel U, Arnett DK, Moreno C, Provoost AP, Jacob HJ. SORCS1 contributes to the development of renal disease in rats and humans. Physiol Genomics 2013; 45:720-8. [PMID: 23780848 PMCID: PMC3742914 DOI: 10.1152/physiolgenomics.00089.2013] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Accepted: 06/14/2013] [Indexed: 12/14/2022] Open
Abstract
Many lines of evidence demonstrate that genetic variability contributes to chronic kidney disease susceptibility in humans as well as rodent models. Little progress has been made in discovering causal kidney disease genes in humans mainly due to genetic complexity. Here, we use a minimal congenic mapping strategy in the FHH (fawn hooded hypertensive) rat to identify Sorcs1 as a novel renal disease candidate gene. We investigated the hypothesis that genetic variation in Sorcs1 influences renal disease susceptibility in both rat and human. Sorcs1 is expressed in the kidney, and knocking out this gene in a rat strain with a sensitized genome background produced increased proteinuria. In vitro knockdown of Sorcs1 in proximal tubule cells impaired protein trafficking, suggesting a mechanism for the observed proteinuria in the FHH rat. Since Sorcs1 influences renal function in the rat, we went on to test this gene in humans. We identified associations between single nucleotide polymorphisms in SORCS1 and renal function in large cohorts of European and African ancestry. The experimental data from the rat combined with association results from different ethnic groups indicates a role for SORCS1 in maintaining proper renal function.
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Affiliation(s)
- Jozef Lazar
- Department of Dermatology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
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18
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He Y, Fang Z, Yu G. Sortilin-related VPS10 domain containing receptor 1 and Alzheimer's disease-associated allelic variations preferentially exist in female or type 2 diabetes mellitus patients in southern Han Chinese. Psychogeriatrics 2012; 12:215-25. [PMID: 23279143 DOI: 10.1111/j.1479-8301.2012.00405.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Both in vitro and in vivo, overexpression of the sortilin-related VPS10 domain containing receptor 1 (SORCS1) protein lowers amyloid-β generation. Recent studies have shown that SORCS1 variations in intron 1 are associated with sporadic Alzheimer's disease (SAD), but the results remain inconsistent. METHODS In order to clarify the role of the SORCS1 gene in southern Han Chinese, we genotyped eight single nucleotide polymorphisms (SNP) of SORCS1 in 128 SAD patients and 92 healthy controls. RESULTS By dividing patients and controls according to apolipoprotein status, sex and whether they had type 2 diabetes mellitus, we found that rs7907690 C allele frequencies were significantly higher in the Alzheimer's disease (AD) patients with type 2 diabetes mellitus than in the controls (P=0.041). Also, the rs600879 GG genotype and G allele worked as protective factors of SAD in women (GG genotype, P=0.007; G allele, P=0.009). In multilocus analysis, the frequency of an eight-single nucleotide polymorphism rs601883/rs7907690/rs600879/rs17277986/rs2900717/rs10884399/rs11193170/rs4918280 CCGGACGG haplotype was significantly higher in AD patients (6.3%), especially in female AD patients (9.5%), than in the controls (0.5%) (P=0.003; P=0.0002). However, the CTGGACGG haplotype was significantly lower in AD patients (9.3%) than in controls (20.3%) (P=0.001). The association remained significant even after Bonferroni correction for the number of haplotypes. CONCLUSION This study provides evidence that variations in the SORCS1 gene influence susceptibility to SAD in southern Han Chinese. The genetic link between AD and SORCS1 gene variations are influenced by ethnic background, sex and whether an individual has type 2 diabetes mellitus.
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Affiliation(s)
- Yanqin He
- Department of Geriatrics, the Second Affiliated Hospital of Nanjing University of Traditional Chinese Medicine, Nanjing, China
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Doray B, Misra S, Qian Y, Brett TJ, Kornfeld S. Do GGA adaptors bind internal DXXLL motifs? Traffic 2012; 13:1315-25. [PMID: 22762444 PMCID: PMC3443260 DOI: 10.1111/j.1600-0854.2012.01396.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Revised: 07/02/2012] [Accepted: 07/04/2012] [Indexed: 12/01/2022]
Abstract
The GGA family of clathrin adaptor proteins mediates the intracellular trafficking of transmembrane proteins by interacting with DXXLL-type sorting signals on the latter. These signals were originally identified at the carboxy-termini of the transmembrane cargo proteins. Subsequent studies, however, showed that internal DXXLL sorting motifs occur within the N- or C-terminal cytoplasmic domains of cargo molecules. The GGAs themselves also contain internal DXXLL motifs that serve to auto-regulate GGA function. A recent study challenged the notion that internal DXXLL signals are competent for binding to GGAs. Since the question of whether GGA adaptors interact with internal DXXLL motifs is fundamental to the identification of bona fide GGA cargo, and to an accurate understanding of GGA regulation within cells, we have extended our previous findings. We now present additional evidence confirming that GGAs do interact with internal DXXLL motifs. We also summarize the recent reports from other laboratories documenting internal GGA binding motifs.
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Affiliation(s)
- Balraj Doray
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO 63110
| | - Saurav Misra
- Department of Molecular Cardiology, Lerner Research Institute, The Cleveland Clinic, Cleveland, OH 44195
| | - Yi Qian
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO 63110
| | - Tom J. Brett
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO 63110
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110
| | - Stuart Kornfeld
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO 63110
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20
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Rogelj B, Easton LE, Bogu GK, Stanton LW, Rot G, Curk T, Zupan B, Sugimoto Y, Modic M, Haberman N, Tollervey J, Fujii R, Takumi T, Shaw CE, Ule J. Widespread binding of FUS along nascent RNA regulates alternative splicing in the brain. Sci Rep 2012; 2:603. [PMID: 22934129 PMCID: PMC3429604 DOI: 10.1038/srep00603] [Citation(s) in RCA: 204] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2012] [Accepted: 08/13/2012] [Indexed: 12/12/2022] Open
Abstract
Fused in sarcoma (FUS) and TAR DNA-binding protein 43 (TDP-43) are RNA-binding proteins pathogenetically linked to amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD), but it is not known if they regulate the same transcripts. We addressed this question using crosslinking and immunoprecipitation (iCLIP) in mouse brain, which showed that FUS binds along the whole length of the nascent RNA with limited sequence specificity to GGU and related motifs. A saw-tooth binding pattern in long genes demonstrated that FUS remains bound to pre-mRNAs until splicing is completed. Analysis of FUS(-/-) brain demonstrated a role for FUS in alternative splicing, with increased crosslinking of FUS in introns around the repressed exons. We did not observe a significant overlap in the RNA binding sites or the exons regulated by FUS and TDP-43. Nevertheless, we found that both proteins regulate genes that function in neuronal development.
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Affiliation(s)
- Boris Rogelj
- Centre for Neurodegeneration Research, King's College London, Institute of Psychiatry, De Crespigny Park, London SE5 8AF, UK
- Now at: Department of Biotechnology, Jožef Stefan Institute, Jamova 39, SI-1000, Ljubljana, Slovenia
- These authors contributed equally to this work
| | - Laura E. Easton
- MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 0QH, UK
- These authors contributed equally to this work
| | - Gireesh K. Bogu
- Stem Cell and Developmental Biology Group, Genome Institute of Singapore, 60 Biopolis Street, S(138672), Singapore
| | - Lawrence W. Stanton
- Stem Cell and Developmental Biology Group, Genome Institute of Singapore, 60 Biopolis Street, S(138672), Singapore
| | - Gregor Rot
- Faculty of Computer and Information Science, University of Ljubljana, Tržaška 25, SI-1000, Ljubljana, Slovenia
| | - Tomaž Curk
- Faculty of Computer and Information Science, University of Ljubljana, Tržaška 25, SI-1000, Ljubljana, Slovenia
| | - Blaž Zupan
- Faculty of Computer and Information Science, University of Ljubljana, Tržaška 25, SI-1000, Ljubljana, Slovenia
| | - Yoichiro Sugimoto
- MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 0QH, UK
| | - Miha Modic
- MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 0QH, UK
| | - Nejc Haberman
- MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 0QH, UK
| | - James Tollervey
- MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 0QH, UK
- Now at: The Buck Institute for Research on Aging, 8001 Redwood Blvd., Novato, CA 94945, USA
| | - Ritsuko Fujii
- Graduate School of Biomedical Sciences, Hiroshima University, 1-2-3 Kasumi, Minami, Hiroshima 734-8553, Japan
| | - Toru Takumi
- Graduate School of Biomedical Sciences, Hiroshima University, 1-2-3 Kasumi, Minami, Hiroshima 734-8553, Japan
| | - Christopher E. Shaw
- Centre for Neurodegeneration Research, King's College London, Institute of Psychiatry, De Crespigny Park, London SE5 8AF, UK
- These authors contributed equally to this work
| | - Jernej Ule
- MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 0QH, UK
- These authors contributed equally to this work
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21
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Wang HF, Yu JT, Zhang W, Wang W, Liu QY, Ma XY, Ding HM, Tan L. SORCS1 and APOE polymorphisms interact to confer risk for late-onset Alzheimer's disease in a Northern Han Chinese population. Brain Res 2012; 1448:111-6. [PMID: 22353753 DOI: 10.1016/j.brainres.2012.01.067] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2011] [Revised: 01/09/2012] [Accepted: 01/27/2012] [Indexed: 12/13/2022]
Abstract
Sortilin-related VPS domain containing receptor 1 (SORCS1), is located on chromosome 10q23.3, a chromosomal region of interest in Alzheimer's disease (AD) defined by many genome-wide and chromosome10-specific studies. Recently, three intronic variants (rs12571141, rs17277986 and rs6584777) within SORCS1 were reported to be associated with AD in Caucasian. In order to assess the involvement of the SORCS1 polymorphisms in the progression of late-onset AD (LOAD), we conducted an independent replication study in 1198 unrelated Northern Han Chinese subjects comprising 598 LOAD patients and 600 healthy controls matched for gender and age. The results revealed no significant differences in the distributions of genotype or allele between LOAD and control groups in the total sample. However, when these data were stratified by the Apolipoprotein E (APOE) ε4 status, we observed significant differences in the genotypes and allele frequencies (rs12571141: P=0.001, rs17277986: P=0.005, rs6584777: P=0.023) in APOE ε4 allele carriers. Moreover, the association was further demonstrated in logistic regression analysis (rs12571141: P=0.002, OR=0.424; rs17277986: P=0.004, OR=0.447; rs6584777: P=0.019, OR=0.523) and haplotype analysis (GCC: P=0.002, ATT: P=0.002, ACC: P=0.025) in this subset. Our data suggested that SORCS1 was in interaction with APOE in the development of LOAD in a Northern Han Chinese population.
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Affiliation(s)
- Hui-Fu Wang
- Department of Neurology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, Qingdao 266071, China
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22
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Diabetes-associated SorCS1 regulates Alzheimer's amyloid-beta metabolism: evidence for involvement of SorL1 and the retromer complex. J Neurosci 2010; 30:13110-5. [PMID: 20881129 DOI: 10.1523/jneurosci.3872-10.2010] [Citation(s) in RCA: 122] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
SorCS1 and SorL1/SorLA/LR11 belong to the sortilin family of vacuolar protein sorting-10 (Vps10) domain-containing proteins. Both are genetically associated with Alzheimer's disease (AD), and SORL1 expression is decreased in the brains of patients suffering from AD. SORCS1 is also genetically associated with types 1 and 2 diabetes mellitus (T1DM, T2DM). We have undertaken a study of the possible role(s) for SorCS1 in metabolism of the Alzheimer's amyloid-β peptide (Aβ) and the Aβ precursor protein (APP), to test the hypothesis that Sorcs1 deficiency might be a common genetic risk factor underlying the predisposition to AD that is associated with T2DM. Overexpression of SorCS1cβ-myc in cultured cells caused a reduction (p = 0.002) in Aβ generation. Conversely, endogenous murine Aβ(40) and Aβ(42) levels were increased (Aβ(40), p = 0.044; Aβ(42), p = 0.007) in the brains of female Sorcs1 hypomorphic mice, possibly paralleling the sexual dimorphism that is characteristic of the genetic associations of SORCS1 with AD and DM. Since SorL1 directly interacts with Vps35 to modulate APP metabolism, we investigated the possibility that SorCS1cβ-myc interacts with APP, SorL1, and/or Vps35. We readily recovered SorCS1:APP, SorCS1:SorL1, and SorCS1:Vps35 complexes from nontransgenic mouse brain. Notably, total Vps35 protein levels were decreased by 49% (p = 0.009) and total SorL1 protein levels were decreased by 29% (p = 0.003) in the brains of female Sorcs1 hypomorphic mice. From these data, we propose that dysfunction of SorCS1 may contribute to both the APP/Aβ disturbance underlying AD and the insulin/glucose disturbance underlying DM.
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23
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Chen SC, Lu G, Chan CY, Chen Y, Wang H, Yew DTW, Feng ZT, Kung HF. Microarray Profile of Brain Aging-Related Genes in the Frontal Cortex of SAMP8. J Mol Neurosci 2009; 41:12-6. [DOI: 10.1007/s12031-009-9215-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2009] [Accepted: 06/30/2009] [Indexed: 12/23/2022]
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24
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Hermey G. The Vps10p-domain receptor family. Cell Mol Life Sci 2009; 66:2677-89. [PMID: 19434368 PMCID: PMC11115710 DOI: 10.1007/s00018-009-0043-1] [Citation(s) in RCA: 154] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2009] [Revised: 04/21/2009] [Accepted: 04/21/2009] [Indexed: 12/24/2022]
Abstract
The family of mammalian type-I transmembrane receptors containing a Vps10p domain contains five members, Sortilin, SorCS1, SorCS2, SorCS3, and SorLA. The common characteristic of these receptors is an N-terminal Vps10p domain, which either represents the only module of the luminal/extracellular moiety or is combined with additional domains. Family members play roles in protein transport and signal transduction. The individual receptors bind and internalize a variety of ligands, such as neuropeptides and trophic factors, and Sortilin and SorLA mediate trans-Golgi network-to-endosome sorting. Their prominent neuronal expression, several of the identified ligands, and recent results support the notion that members of this receptor family have important functions in neurogenesis, plasticity-related processes, and functional maintenance of the nervous system. For instance, it has been demonstrated that Sortilin partakes in the transduction of proapoptotic effects, and there is converging biochemical and genetic evidence that implies that SorLA is an Alzheimer's disease risk factor.
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Affiliation(s)
- Guido Hermey
- Institute of Molecular and Cellular Cognition, Zentrum für Molekulare Neurobiologie Hamburg, Hamburg, Germany.
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25
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Chatterjee S, Szustakowski JD, Nanguneri NR, Mickanin C, Labow MA, Nohturfft A, Dev KK, Sivasankaran R. Identification of novel genes and pathways regulating SREBP transcriptional activity. PLoS One 2009; 4:e5197. [PMID: 19381295 PMCID: PMC2668173 DOI: 10.1371/journal.pone.0005197] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2008] [Accepted: 02/05/2009] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Lipid metabolism in mammals is orchestrated by a family of transcription factors called sterol regulatory element-binding proteins (SREBPs) that control the expression of genes required for the uptake and synthesis of cholesterol, fatty acids, and triglycerides. SREBPs are thus essential for insulin-induced lipogenesis and for cellular membrane homeostasis and biogenesis. Although multiple players have been identified that control the expression and activation of SREBPs, gaps remain in our understanding of how SREBPs are coordinated with other physiological pathways. METHODOLOGY To identify novel regulators of SREBPs, we performed a genome-wide cDNA over-expression screen to identify proteins that might modulate the transcription of a luciferase gene driven from an SREBP-specific promoter. The results were verified through secondary biological assays and expression data were analyzed by a novel application of the Gene Set Enrichment Analysis (GSEA) method. CONCLUSIONS/SIGNIFICANCE We screened 10,000 different cDNAs and identified a number of genes and pathways that have previously not been implicated in SREBP control and cellular cholesterol homeostasis. These findings further our understanding of lipid biology and should lead to new insights into lipid associated disorders.
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Affiliation(s)
- Sandipan Chatterjee
- Developmental and Molecular Pathways, Novartis Institutes for BioMedical Research, Cambridge, Massachusetts, United States of America
| | - Joseph D. Szustakowski
- Developmental and Molecular Pathways, Novartis Institutes for BioMedical Research, Cambridge, Massachusetts, United States of America
| | - Nirmala R. Nanguneri
- Developmental and Molecular Pathways, Novartis Institutes for BioMedical Research, Cambridge, Massachusetts, United States of America
| | - Craig Mickanin
- Developmental and Molecular Pathways, Novartis Institutes for BioMedical Research, Cambridge, Massachusetts, United States of America
| | - Mark A. Labow
- Developmental and Molecular Pathways, Novartis Institutes for BioMedical Research, Cambridge, Massachusetts, United States of America
| | - Axel Nohturfft
- Division of Basic Medical Sciences, St. George's University of London, London, United Kingdom
| | - Kumlesh K. Dev
- Department of Anatomy, University College Cork, Cork, Ireland
- * E-mail: (KKD); (RS)
| | - Rajeev Sivasankaran
- Developmental and Molecular Pathways, Novartis Institutes for BioMedical Research, Cambridge, Massachusetts, United States of America
- * E-mail: (KKD); (RS)
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26
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VPS10P-domain receptors — regulators of neuronal viability and function. Nat Rev Neurosci 2008; 9:899-909. [DOI: 10.1038/nrn2516] [Citation(s) in RCA: 189] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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27
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Nielsen MS, Keat SJ, Hamati JW, Madsen P, Gutzmann JJ, Engelsberg A, Pedersen KM, Gustafsen C, Nykjaer A, Gliemann J, Hermans-Borgmeyer I, Kuhl D, Petersen CM, Hermey G. Different motifs regulate trafficking of SorCS1 isoforms. Traffic 2008; 9:980-94. [PMID: 18315530 DOI: 10.1111/j.1600-0854.2008.00731.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The type I transmembrane protein SorCS1 is a member of the Vps10p-domain receptor family comprised of Sortilin, SorLA and SorCS1, -2 and -3. Current information indicates that Sortilin and SorLA mediate intracellular protein trafficking and sorting, but little is known about the cellular functions of the SorCS subgroup. SorCS1 binds platelet-derived growth factor-BB (PDGF-BB) and is expressed in isoforms differing only in their cytoplasmic domains. Here, we identify two novel isoforms of mouse SorCS1 designated m-SorCS1c and -d. In situ hybridization revealed a combinatorial expression pattern of the variants in brain and embryonic tissues. We demonstrate that among the mouse variants, only SorCS1c mediates internalization and that the highly conserved SorCS1c is internalized through a canonical tyrosine-based motif. In contrast, human SorCS1a, whose cytoplasmic domain is completely different from mouse SorCS1a, is internalized through a DXXLL motif. We report that the human SorCS1a cytoplasmic domain interacts with the alphaC/sigma2 subunits of the adaptor protein (AP)-2 complex, and internalization of human SorCS1a and -c is mediated by AP-2. Our results suggest that the endocytic isoforms target internalized cargo to lysosomes but are not engaged in Golgi-endosomal transport to a significant degree.
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Affiliation(s)
- Morten S Nielsen
- MIND center, Department of Medical Biochemistry, University of Aarhus, Aarhus, Denmark
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28
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Goodarzi MO, Lehman DM, Taylor KD, Guo X, Cui J, Quiñones MJ, Clee SM, Yandell BS, Blangero J, Hsueh WA, Attie AD, Stern MP, Rotter JI. SORCS1: a novel human type 2 diabetes susceptibility gene suggested by the mouse. Diabetes 2007; 56:1922-9. [PMID: 17426289 DOI: 10.2337/db06-1677] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE A small number of susceptibility genes for human type 2 diabetes have been identified by candidate gene analysis or positional cloning. Genes found to influence diabetes or related traits in mice are likely to be susceptibility genes in humans. SorCS1 is the gene identified as responsible for the mouse chromosome 19 T2dm2 quantitative trait locus for fasting insulin levels, acting via impaired insulin secretion and increased islet disruption in obese females. Genes that impair compensatory insulin secretion in response to obesity-induced insulin resistance may be particularly relevant to human diabetes. Thus, we sought to determine whether variation in the human SORCS1 gene was associated with diabetes-related traits. RESEARCH DESIGN AND METHODS We assessed the contribution of variation in SORCS1 to human insulin-related traits in two distinct Mexican-American cohorts. One cohort (the Mexican-American Coronary Artery Disease [MACAD] cohort) consisted of nondiabetic individuals, allowing assessment of genetic association with subclinical intermediate insulin-related traits; the second cohort (the San Antonio Family Diabetes Study [SAFADS]) contained individuals with diabetes, allowing association analyses with overt disease. RESULTS We first found association of SORCS1 single nucleotide polymorphisms and haplotypes with fasting insulin levels and insulin secretion in the MACAD cohort. Similar to our results in the mice, the genetic association was strongest in overweight women. We then observed association with diabetes risk and age at diagnosis in women of the SAFADS cohort. CONCLUSIONS Identification of SORCS1 as a novel gene affecting insulin secretion and diabetes risk is likely to provide important insight into the biology of obesity-induced type 2 diabetes.
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Affiliation(s)
- Mark O Goodarzi
- Cedars-Sinai Medical Center, Division of Endocrinology, Diabetes, and Metabolism, 8700 Beverly Blvd., Becker B-131, Los Angeles, CA 90048, USA.
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Yaar M, Zhai S, Panova I, Fine RE, Eisenhauer PB, Blusztajn JK, Lopez-Coviella I, Gilchrest BA. A cyclic peptide that binds p75(NTR) protects neurones from beta amyloid (1-40)-induced cell death. Neuropathol Appl Neurobiol 2007; 33:533-43. [PMID: 17596181 DOI: 10.1111/j.1365-2990.2007.00844.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The current study determined the ability of a p75(NTR) antagonistic cyclic peptide to rescue cells from beta amyloid (Abeta) (1-40)-induced death. p75(NTR)-, p140(trkA)-NIH-3T3 cells or E17 foetal rat cortical neurones were incubated with 125I-NGF or 125I-Abeta (1-40) and increasing concentrations of the cyclic peptide (CATDIKGAEC). Peptide ability to displace 125I-NGF or 125I-Abeta (1-40) binding was determined. Duplicate cultures were preincubated with CATDIKGAEC (250 nM) or diluent and then stimulated with Abeta (1-40). Peptide ability to displace Abeta (1-40) binding, interfere with Abeta (1-40)-induced signalling and rescue cells from Abeta-mediated toxicity was determined by immunoprecipitation and autoradiography, Northern blotting, JNK activation, MTT and trypan blue assays. The peptide inhibited NGF and Abeta (1-40) binding to p75(NTR), but not to p140(trkA). Abeta (1-40) induced c-jun transcription (57.3% +/- 0.07%) in diluent-treated p75(NTR)-cells, but not in cells preincubated with the cyclic peptide. Also, at 250 nM, the peptide reduced Abeta (1-40)-induced phosphorylation of JNK by 71.8% +/- 0.03% and protected neurones against Abeta-induced toxicity as determined by: trypan blue exclusion assay (53% +/- 11% trypan blue-positive cells in diluent pretreated cultures vs. 28% +/- 5% in cyclic peptide-pretreated cultures); MTT assay (0.09 +/-0.03 units in diluent-pretreated cells vs. 0.12 +/- 0.004 units in cyclic peptide-pretreated cells); and visualization of representative microscopic fields. Our data suggest that a cyclic peptide homologous to amino acids 28-36 of NGF known to mediate binding to p75(NTR) can interfere with Abeta (1-40) signalling and rescue neurones from Abeta (1-40)-induced toxicity.
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Affiliation(s)
- M Yaar
- Department of Dermatology, Boston University School of Medicine, Boston, MA 02118-2394, USA.
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Nyborg AC, Ladd TB, Zwizinski CW, Lah JJ, Golde TE. Sortilin, SorCS1b, and SorLA Vps10p sorting receptors, are novel gamma-secretase substrates. Mol Neurodegener 2006; 1:3. [PMID: 16930450 PMCID: PMC1513133 DOI: 10.1186/1750-1326-1-3] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2006] [Accepted: 06/12/2006] [Indexed: 11/30/2022] Open
Abstract
Background The mammalian Vps10p sorting receptor family is a group of 5 type I membrane homologs (Sortilin, SorLA, and SorCS1-3). These receptors bind various cargo proteins via their luminal Vps10p domains and have been shown to mediate a variety of intracellular sorting and trafficking functions. These proteins are highly expressed in the brain. SorLA has been shown to be down regulated in Alzheimer's disease brains, interact with ApoE, and modulate Aβ production. Sortilin has been shown to be part of proNGF mediated death signaling that results from a complex of Sortilin, p75NTR and proNGF. We have investigated and provide evidence for γ-secretase cleavage of this family of proteins. Results We provide evidence that these receptors are substrates for presenilin dependent γ-secretase cleavage. γ-Secretase cleavage of these sorting receptors is inhibited by γ-secretase inhibitors and does not occur in PS1/PS2 knockout cells. Like most γ-secretase substrates, we find that ectodomain shedding precedes γ-secretase cleavage. The ectodomain cleavage is inhibited by a metalloprotease inhibitor and activated by PMA suggesting that it is mediated by an α-secretase like cleavage. Conclusion These data indicate that the α- and γ-secretase cleavages of the mammalian Vps10p sorting receptors occur in a fashion analogous to other known γ-secretase substrates, and could possibly regulate the biological functions of these proteins.
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Affiliation(s)
- Andrew C Nyborg
- Department of Neuroscience, Mayo Clinic Jacksonville, Mayo Clinic College of Medicine, 4500 San Pablo Road, Jacksonville, Florida 32224, USA
| | - Thomas B Ladd
- Department of Neuroscience, Mayo Clinic Jacksonville, Mayo Clinic College of Medicine, 4500 San Pablo Road, Jacksonville, Florida 32224, USA
| | - Craig W Zwizinski
- Department of Neuroscience, Mayo Clinic Jacksonville, Mayo Clinic College of Medicine, 4500 San Pablo Road, Jacksonville, Florida 32224, USA
| | - James J Lah
- Department of Neurology, Center for Neurodegenerative Disease, Emory University, Whitehead Biomedical Research Building, 615 Michael Street, Suite 505, Atlanta, GA 30322, USA
| | - Todd E Golde
- Department of Neuroscience, Mayo Clinic Jacksonville, Mayo Clinic College of Medicine, 4500 San Pablo Road, Jacksonville, Florida 32224, USA
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Clee SM, Yandell BS, Schueler KM, Rabaglia ME, Richards OC, Raines SM, Kabara EA, Klass DM, Mui ETK, Stapleton DS, Gray-Keller MP, Young MB, Stoehr JP, Lan H, Boronenkov I, Raess PW, Flowers MT, Attie AD. Positional cloning of Sorcs1, a type 2 diabetes quantitative trait locus. Nat Genet 2006; 38:688-93. [PMID: 16682971 DOI: 10.1038/ng1796] [Citation(s) in RCA: 133] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2005] [Accepted: 04/06/2006] [Indexed: 11/08/2022]
Abstract
We previously mapped the type 2 diabetes mellitus-2 locus (T2dm2), which affects fasting insulin levels, to distal chromosome 19 in a leptin-deficient obese F2 intercross derived from C57BL/6 (B6) and BTBR T+ tf/J (BTBR) mice. Introgression of a 7-Mb segment of the B6 chromosome 19 into the BTBR background (strain 1339A) replicated the reduced insulin linked to T2dm2. The 1339A mice have markedly impaired insulin secretion in vivo and disrupted islet morphology. We used subcongenic strains derived from 1339A to localize the T2dm2 quantitative trait locus (QTL) to a 242-kb segment comprising the promoter, first exon and most of the first intron of the Sorcs1 gene. This was the only gene in the 1339A strain for which we detected amino acid substitutions and expression level differences between mice carrying B6 and BTBR alleles of this insert, thereby identifying variation within the Sorcs1 gene as underlying the phenotype associated with the T2dm2 locus. SorCS1 binds platelet-derived growth factor, a growth factor crucial for pericyte recruitment to the microvasculature, and may thus have a role in expanding or maintaining the islet vasculature. Our identification of the Sorcs1 gene provides insight into the pathway underlying the pathophysiology of obesity-induced type 2 diabetes mellitus.
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Affiliation(s)
- Susanne M Clee
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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Hermey G, Sjøgaard S, Petersen C, Nykjær A, Gliemann J. Tumour necrosis factor alpha-converting enzyme mediates ectodomain shedding of Vps10p-domain receptor family members. Biochem J 2006; 395:285-93. [PMID: 16393139 PMCID: PMC1422770 DOI: 10.1042/bj20051364] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Several transmembrane molecules are cleaved at juxtamembrane extracellular sites leading to shedding of ectodomains. We analysed shedding of members of the Vps10p-D (Vps10p domain; where Vps is vacuolar protein sorting) family of neuronal type-I receptors with partially overlapping functions, and additional proteolytic events initiated by the shedding. When transfected into CHO (Chinese-hamster ovary) cells (CHO-K1), sorCS1a-sorCS1c isoforms were shed at high rates (approximately 0.61% x min(-1)) that were increased approx. 3-fold upon stimulation with phorbol ester. sorCS1c identified in the cultured neuroblastoma cell line SH-SY5Y was shed similarly. In CHO-K1 transfectants, constitutive and stimulated shedding of sorCS3 also occurred at high rates (0.29% and 1.03% x min(-1)). By comparison, constitutive and stimulated shedding of sorLA occurred at somewhat lower rates (0.07% and 0.48% x min(-1)), whereas sorCS2 and sortilin were shed at very low rates even when stimulated (approximately 0.01% x min(-1)). Except for sorCS2, shedding of the receptors was dramatically reduced in mutant CHO cells (CHO-M2) devoid of active TACE (tumour necrosis factor alpha-converting enzyme), demonstrating that this enzyme accounts for most sheddase activity. The release of sorCS1 and sorLA ectodomains initiated rapid cleavage of the membrane-tethered C-terminal stubs that accumulated only in the presence of gamma-secretase inhibitors. Purified shed sorLA bound several ligands similarly to the entire luminal domain of the receptor, including PDGF-BB (platelet-derived growth factor-BB) and amyloid-beta precursor protein. In addition, PDGF-BB also bound to the luminal domains of sorCS1 and sorCS3. The results suggest that ectodomains shed from a subset of Vps10p-D receptors can function as carrier proteins.
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Affiliation(s)
- Guido Hermey
- Institute of Medical Biochemistry, MIND Center, Ole Worms Allé, Building 1170, University of Aarhus, 8000 Århus C, Denmark
| | - Susanne S. Sjøgaard
- Institute of Medical Biochemistry, MIND Center, Ole Worms Allé, Building 1170, University of Aarhus, 8000 Århus C, Denmark
| | - Claus Munck Petersen
- Institute of Medical Biochemistry, MIND Center, Ole Worms Allé, Building 1170, University of Aarhus, 8000 Århus C, Denmark
| | - Anders Nykjær
- Institute of Medical Biochemistry, MIND Center, Ole Worms Allé, Building 1170, University of Aarhus, 8000 Århus C, Denmark
| | - Jørgen Gliemann
- Institute of Medical Biochemistry, MIND Center, Ole Worms Allé, Building 1170, University of Aarhus, 8000 Århus C, Denmark
- To whom correspondence should be addressed (email )
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Westergaard UB, Kirkegaard K, Sørensen ES, Jacobsen C, Nielsen MS, Petersen CM, Madsen P. SorCS3 does not require propeptide cleavage to bind nerve growth factor. FEBS Lett 2005; 579:1172-6. [PMID: 15710408 DOI: 10.1016/j.febslet.2004.12.088] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2004] [Revised: 12/02/2004] [Accepted: 12/23/2004] [Indexed: 11/16/2022]
Abstract
The functional properties of the Vps10p-domain receptor SorCS3 are undescribed. Here, we examine its processing and sorting in cellular transfectants, and analyze the binding of potential ligands to the purified receptor. We show that SorCS3 is synthesized as a proprotein and converted to its mature form by N-terminal propeptide cleavage in distal Golgi compartments. The propeptide is not a requirement for normal processing of the receptor and does not prevent ligands from binding to the SorCS3 precursor form. Expression of wt and chimeric receptors further suggests that SorCS3 predominates on the plasma membrane, exhibits slow internalization and does not engage in intracellular trafficking. SorCS3 emerges as a new neurotrophin binding Vps10p-domain receptor functionally distinct from its relatives Sortilin and SorLA.
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Affiliation(s)
- U B Westergaard
- Institute of Medical Biochemistry, Ole Worms Allé, bldg. 170, University of Aarhus, 8000 Aarhus C, Denmark
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Abstract
In the year 2003 there was a 17% increase in the number of publications citing work performed using optical biosensor technology compared with the previous year. We collated the 962 total papers for 2003, identified the geographical regions where the work was performed, highlighted the instrument types on which it was carried out, and segregated the papers by biological system. In this overview, we spotlight 13 papers that should be on everyone's 'must read' list for 2003 and provide examples of how to identify and interpret high-quality biosensor data. Although we still find that the literature is replete with poorly performed experiments, over-interpreted results and a general lack of understanding of data analysis, we are optimistic that these shortcomings will be addressed as biosensor technology continues to mature.
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Affiliation(s)
- Rebecca L Rich
- Center for Biomolecular Interaction Analysis, University of Utah, Salt Lake City, UT 84132, USA
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Gliemann J, Hermey G, Nykjaer A, Petersen CM, Jacobsen C, Andreasen PA. The mosaic receptor sorLA/LR11 binds components of the plasminogen-activating system and platelet-derived growth factor-BB similarly to LRP1 (low-density lipoprotein receptor-related protein), but mediates slow internalization of bound ligand. Biochem J 2004; 381:203-12. [PMID: 15053742 PMCID: PMC1133778 DOI: 10.1042/bj20040149] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2004] [Revised: 03/24/2004] [Accepted: 03/30/2004] [Indexed: 11/17/2022]
Abstract
The type-1 receptor sorLA/LR11, a member of the Vps10p-domain receptor family that also contains domains characterizing members of the LDL (low-density lipoprotein) receptor family, has been shown to induce increased uPAR (urokinase receptor) expression as well as enhanced migration and invasion activities in smooth muscle cells in the presence of PDGF-BB (platelet-derived growth factor-BB). Here we show that sorLA interacts with both components of the plasminogen activating system and PDGF-BB similarly to LRP1 (LDL receptor-related protein/alpha2-macroglobulin receptor), which is an important clearance receptor with established functions in controlling uPAR expression as well as PDGF-BB signalling. In contrast with LRP1, sorLA does not interact with alpha2-macroglobulin, which is a binding protein for several growth factors, including PDGF-BB. By using LRP1-deficient cells transfected with sorLA, we demonstrate that sorLA-bound ligand is internalized at a much lower rate than LRP1-bound ligand, and that sorLA is inefficient in regulating cell surface uPAR expression, which depends on rapid internalization of the ternary complex between urokinase-type plasminogen activator, its type-1 inhibitor, and uPAR. Thus, although overlapping with regard to binding profiles, sorLA is substantially less efficient as a clearance receptor than LRP1. We propose that sorLA can divert ligands away from LRP1 and thereby inhibit both their clearance and signalling events mediated by LRP1.
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Affiliation(s)
- Jørgen Gliemann
- Institute of Medical Biochemistry, University of Aarhus, Ole Worms Allé bldg 170, DK-8000 Arhus C, Denmark.
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Westergaard UB, Sørensen ES, Hermey G, Nielsen MS, Nykjaer A, Kirkegaard K, Jacobsen C, Gliemann J, Madsen P, Petersen CM. Functional organization of the sortilin Vps10p domain. J Biol Chem 2004; 279:50221-9. [PMID: 15364913 DOI: 10.1074/jbc.m408873200] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A Vps10p domain makes up the entire luminal part of Sortilin, and this type of domain is the hallmark of a new family of neuronal receptors that target a variety of ligands, including neurotrophins and neuropeptides. We have shown that two structural features of the Vps10p domain, the N-terminal propeptide and the C-terminal segment of ten conserved cysteines (10CC), are key elements in the function of Sortilin. The propeptide has two functions. (i) It binds the mature part of Sortilin and prevents ligands in the biosynthetic pathway from binding to the uncleaved proreceptor, and (ii) it facilitates receptor transport in early Golgi compartments by a mechanism that does not depend on its ability to prevent ligand binding. In contrast, other Vps10p domain receptors, such as SorLA and SorCS3, do not need their propeptide for normal and swift processing. The 10CC segment constitutes an exchangeable module containing five conserved disulfide bridges, and using module-shuffling and truncations, we have shown that the 10CC segment is a major ligand-binding region in Sortilin.
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Affiliation(s)
- Uffe B Westergaard
- Institute of Medical Biochemistry, Ole Worms Allé, Building 170, University of Aarhus, Aarhus, Denmark
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Hermey G, Plath N, Hübner CA, Kuhl D, Schaller HC, Hermans-Borgmeyer I. The three sorCS genes are differentially expressed and regulated by synaptic activity. J Neurochem 2004; 88:1470-6. [PMID: 15009648 DOI: 10.1046/j.1471-4159.2004.02286.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We have isolated the murine sorCS3 gene, a new member of the family of receptors containing a Vps10p-domain. Receptors of this family facilitate rapid endocytosis and are thought to be involved in intracellular sorting. SorCS3 and the highly homologous sorCS1 and sorCS2 genes were expressed in a combinatorial, mostly non-overlapping pattern in both the developing and mature central nervous system. During development, distribution and abundancy of their transcripts was regulated. Moreover, their expression was differentially influenced by neuronal activity in the hippocampus of adult mice. Although kainic acid-induced seizures had no effect on sorCS2 mRNA levels, they dramatically increased the expression of sorCS1 and sorCS3. The activity-dependent induction of sorCS1 expression required de novo protein synthesis, whereas that of sorCS3 did not. Our results imply that the three sorCS genes have diverse, but partly overlapping functions in the developing and mature central nervous system.
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Affiliation(s)
- Guido Hermey
- Zentram für Molekulare Neurobiologie, Universität Hamburg, Germany
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Nykjaer A, Lee R, Teng KK, Jansen P, Madsen P, Nielsen MS, Jacobsen C, Kliemannel M, Schwarz E, Willnow TE, Hempstead BL, Petersen CM. Sortilin is essential for proNGF-induced neuronal cell death. Nature 2004; 427:843-8. [PMID: 14985763 DOI: 10.1038/nature02319] [Citation(s) in RCA: 699] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2003] [Accepted: 12/23/2003] [Indexed: 11/09/2022]
Abstract
Sortilin (approximately 95 kDa) is a member of the recently discovered family of Vps10p-domain receptors, and is expressed in a variety of tissues, notably brain, spinal cord and muscle. It acts as a receptor for neurotensin, but predominates in regions of the nervous system that neither synthesize nor respond to this neuropeptide, suggesting that sortilin has additional roles. Sortilin is expressed during embryogenesis in areas where nerve growth factor (NGF) and its precursor, proNGF, have well-characterized effects. These neurotrophins can be released by neuronal tissues, and they regulate neuronal development through cell survival and cell death signalling. NGF regulates cell survival and cell death via binding to two different receptors, TrkA and p75NTR (ref. 10). In contrast, proNGF selectively induces apoptosis through p75NTR but not TrkA. However, not all p75NTR-expressing cells respond to proNGF, suggesting that additional membrane proteins are required for the induction of cell death. Here we report that proNGF creates a signalling complex by simultaneously binding to p75NTR and sortilin. Thus sortilin acts as a co-receptor and molecular switch governing the p75NTR-mediated pro-apoptotic signal induced by proNGF.
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Affiliation(s)
- Anders Nykjaer
- Department of Medical Biochemistry, Ole Worms Allé 170, Aarhus University, Gustav Wieds vej 10, DK-8000 Aarhus C, Denmark.
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