1
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Mosquera-Heredia MI, Vidal OM, Morales LC, Silvera-Redondo C, Barceló E, Allegri R, Arcos-Burgos M, Vélez JI, Garavito-Galofre P. Long Non-Coding RNAs and Alzheimer's Disease: Towards Personalized Diagnosis. Int J Mol Sci 2024; 25:7641. [PMID: 39062884 PMCID: PMC11277322 DOI: 10.3390/ijms25147641] [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: 05/25/2024] [Revised: 07/06/2024] [Accepted: 07/08/2024] [Indexed: 07/28/2024] Open
Abstract
Alzheimer's disease (AD), a neurodegenerative disorder characterized by progressive cognitive decline, is the most common form of dementia. Currently, there is no single test that can diagnose AD, especially in understudied populations and developing countries. Instead, diagnosis is based on a combination of medical history, physical examination, cognitive testing, and brain imaging. Exosomes are extracellular nanovesicles, primarily composed of RNA, that participate in physiological processes related to AD pathogenesis such as cell proliferation, immune response, and neuronal and cardiovascular function. However, the identification and understanding of the potential role of long non-coding RNAs (lncRNAs) in AD diagnosis remain largely unexplored. Here, we clinically, cognitively, and genetically characterized a sample of 15 individuals diagnosed with AD (cases) and 15 controls from Barranquilla, Colombia. Advanced bioinformatics, analytics and Machine Learning (ML) techniques were used to identify lncRNAs differentially expressed between cases and controls. The expression of 28,909 lncRNAs was quantified. Of these, 18 were found to be differentially expressed and harbored in pivotal genes related to AD. Two lncRNAs, ENST00000608936 and ENST00000433747, show promise as diagnostic markers for AD, with ML models achieving > 95% sensitivity, specificity, and accuracy in both the training and testing datasets. These findings suggest that the expression profiles of lncRNAs could significantly contribute to advancing personalized AD diagnosis in this community, offering promising avenues for early detection and follow-up.
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Affiliation(s)
- Maria I. Mosquera-Heredia
- Department of Medicine, Universidad del Norte, Barranquilla 081007, Colombia; (M.I.M.-H.); (O.M.V.); (L.C.M.); (C.S.-R.)
| | - Oscar M. Vidal
- Department of Medicine, Universidad del Norte, Barranquilla 081007, Colombia; (M.I.M.-H.); (O.M.V.); (L.C.M.); (C.S.-R.)
| | - Luis C. Morales
- Department of Medicine, Universidad del Norte, Barranquilla 081007, Colombia; (M.I.M.-H.); (O.M.V.); (L.C.M.); (C.S.-R.)
| | - Carlos Silvera-Redondo
- Department of Medicine, Universidad del Norte, Barranquilla 081007, Colombia; (M.I.M.-H.); (O.M.V.); (L.C.M.); (C.S.-R.)
| | - Ernesto Barceló
- Instituto Colombiano de Neuropedagogía, Barranquilla 080020, Colombia;
- Department of Health Sciences, Universidad de La Costa, Barranquilla 080002, Colombia
- Grupo Internacional de Investigación Neuro-Conductual (GIINCO), Universidad de La Costa, Barranquilla 080002, Colombia
| | - Ricardo Allegri
- Institute for Neurological Research FLENI, Montañeses 2325, Buenos Aires C1428AQK, Argentina;
| | - Mauricio Arcos-Burgos
- Grupo de Investigación en Psiquiatría (GIPSI), Departamento de Psiquiatría, Instituto de Investigaciones Médicas, Facultad de Medicina, Universidad de Antioquia, Medellin 050010, Colombia;
| | - Jorge I. Vélez
- Department of Industrial Engineering, Universidad del Norte, Barranquilla 081007, Colombia
| | - Pilar Garavito-Galofre
- Department of Medicine, Universidad del Norte, Barranquilla 081007, Colombia; (M.I.M.-H.); (O.M.V.); (L.C.M.); (C.S.-R.)
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2
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Kundu S, Rohokale R, Lin C, Chen S, Biswas S, Guo Z. Bifunctional glycosphingolipid (GSL) probes to investigate GSL-interacting proteins in cell membranes. J Lipid Res 2024; 65:100570. [PMID: 38795858 PMCID: PMC11261293 DOI: 10.1016/j.jlr.2024.100570] [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: 03/19/2024] [Revised: 05/03/2024] [Accepted: 05/04/2024] [Indexed: 05/28/2024] Open
Abstract
Glycosphingolipids (GSLs) are abundant glycolipids on cells and essential for cell recognition, adhesion, signal transduction, and so on. However, their lipid anchors are not long enough to cross the membrane bilayer. To transduce transmembrane signals, GSLs must interact with other membrane components, whereas such interactions are difficult to investigate. To overcome this difficulty, bifunctional derivatives of II3-β-N-acetyl-D-galactosamine-GA2 (GalNAc-GA2) and β-N-acetyl-D-glucosamine-ceramide (GlcNAc-Cer) were synthesized as probes to explore GSL-interacting membrane proteins in live cells. Both probes contain photoreactive diazirine in the lipid moiety, which can crosslink with proximal membrane proteins upon photoactivation, and clickable alkyne in the glycan to facilitate affinity tag addition for crosslinked protein pull-down and characterization. The synthesis is highlighted by the efficient assembly of simple glycolipid precursors followed by on-site lipid remodeling. These probes were employed to profile GSL-interacting membrane proteins in HEK293 cells. The GalNAc-GA2 probe revealed 312 distinct proteins, with GlcNAc-Cer probe-crosslinked proteins as controls, suggesting the potential influence of the glycan on GSL functions. Many of the proteins identified with the GalNAc-GA2 probe are associated with GSLs, and some have been validated as being specific to this probe. The versatile probe design and experimental protocols are anticipated to be widely applicable to GSL research.
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Affiliation(s)
- Sayan Kundu
- Department of Chemistry, University of Florida, Gainesville, FL, USA
| | - Rajendra Rohokale
- Department of Chemistry, University of Florida, Gainesville, FL, USA
| | - Chuwei Lin
- Department of Biology, Genetics Institute, University of Florida, Gainesville, FL, USA
| | - Sixue Chen
- Department of Biology, Genetics Institute, University of Florida, Gainesville, FL, USA; Department of Biology, University of Mississippi, Oxford, MS, USA
| | - Shayak Biswas
- Department of Chemistry, University of Florida, Gainesville, FL, USA
| | - Zhongwu Guo
- Department of Chemistry, University of Florida, Gainesville, FL, USA.
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3
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Li X, Xiang C, Zhu S, Guo J, Liu C, Wang A, Cao J, Lu Y, Neculai D, Xu P, Feng XH. SNX8 enables lysosome reformation and reverses lysosomal storage disorder. Nat Commun 2024; 15:2553. [PMID: 38519472 PMCID: PMC10959956 DOI: 10.1038/s41467-024-46705-x] [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: 11/15/2022] [Accepted: 03/06/2024] [Indexed: 03/25/2024] Open
Abstract
Lysosomal Storage Disorders (LSDs), which share common phenotypes, including enlarged lysosomes and defective lysosomal storage, are caused by mutations in lysosome-related genes. Although gene therapies and enzyme replacement therapies have been explored, there are currently no effective routine therapies against LSDs. During lysosome reformation, which occurs when the functional lysosome pool is reduced, lysosomal lipids and proteins are recycled to restore lysosome functions. Here we report that the sorting nexin protein SNX8 promotes lysosome tubulation, a process that is required for lysosome reformation, and that loss of SNX8 leads to phenotypes characteristic of LSDs in human cells. SNX8 overexpression rescued features of LSDs in cells, and AAV-based delivery of SNX8 to the brain rescued LSD phenotypes in mice. Importantly, by screening a natural compound library, we identified three small molecules that enhanced SNX8-lysosome binding and reversed LSD phenotypes in human cells and in mice. Altogether, our results provide a potential solution for the treatment of LSDs.
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Affiliation(s)
- Xinran Li
- The MOE Key Laboratory of Biosystems Homeostasis & Protection and Zhejiang Provincial Key Laboratory of Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, 310058, Hangzhou, Zhejiang, China
- Center for Life Sciences, Shaoxing Institute, Zhejiang University, 321000, Shaoxing, Zhejiang, China
- ZJU-Hangzhou Global Scientific and Technological Innovation Center, 311200, Hangzhou, Zhejiang, China
- Cancer Center, Zhejiang University, 310058, Hangzhou, Zhejiang, China
| | - Cong Xiang
- The MOE Key Laboratory of Biosystems Homeostasis & Protection and Zhejiang Provincial Key Laboratory of Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, 310058, Hangzhou, Zhejiang, China
- Center for Life Sciences, Shaoxing Institute, Zhejiang University, 321000, Shaoxing, Zhejiang, China
- Cancer Center, Zhejiang University, 310058, Hangzhou, Zhejiang, China
| | - Shilei Zhu
- The MOE Key Laboratory of Biosystems Homeostasis & Protection and Zhejiang Provincial Key Laboratory of Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, 310058, Hangzhou, Zhejiang, China
- Center for Life Sciences, Shaoxing Institute, Zhejiang University, 321000, Shaoxing, Zhejiang, China
- Cancer Center, Zhejiang University, 310058, Hangzhou, Zhejiang, China
| | - Jiansheng Guo
- Center of Cryo-Electron Microscopy, Zhejiang University, Hangzhou, Zhejiang, China
| | - Chang Liu
- The MOE Key Laboratory of Biosystems Homeostasis & Protection and Zhejiang Provincial Key Laboratory of Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, 310058, Hangzhou, Zhejiang, China
- Center for Life Sciences, Shaoxing Institute, Zhejiang University, 321000, Shaoxing, Zhejiang, China
- Cancer Center, Zhejiang University, 310058, Hangzhou, Zhejiang, China
| | - Ailian Wang
- The MOE Key Laboratory of Biosystems Homeostasis & Protection and Zhejiang Provincial Key Laboratory of Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, 310058, Hangzhou, Zhejiang, China
- Center for Life Sciences, Shaoxing Institute, Zhejiang University, 321000, Shaoxing, Zhejiang, China
- Cancer Center, Zhejiang University, 310058, Hangzhou, Zhejiang, China
| | - Jin Cao
- The MOE Key Laboratory of Biosystems Homeostasis & Protection and Zhejiang Provincial Key Laboratory of Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, 310058, Hangzhou, Zhejiang, China
- Center for Life Sciences, Shaoxing Institute, Zhejiang University, 321000, Shaoxing, Zhejiang, China
- Cancer Center, Zhejiang University, 310058, Hangzhou, Zhejiang, China
| | - Yan Lu
- The MOE Key Laboratory of Biosystems Homeostasis & Protection and Zhejiang Provincial Key Laboratory of Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, 310058, Hangzhou, Zhejiang, China
- Cancer Center, Zhejiang University, 310058, Hangzhou, Zhejiang, China
- International Institutes of Medicine, The Fourth Affiliated Hospital of Zhejiang University School of Medicine, Yiwu, China
- Department of Cell Biology, and Department of General Surgery of Sir Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Dante Neculai
- International Institutes of Medicine, The Fourth Affiliated Hospital of Zhejiang University School of Medicine, Yiwu, China
- Department of Cell Biology, and Department of General Surgery of Sir Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Pinglong Xu
- The MOE Key Laboratory of Biosystems Homeostasis & Protection and Zhejiang Provincial Key Laboratory of Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, 310058, Hangzhou, Zhejiang, China
- Center for Life Sciences, Shaoxing Institute, Zhejiang University, 321000, Shaoxing, Zhejiang, China
- ZJU-Hangzhou Global Scientific and Technological Innovation Center, 311200, Hangzhou, Zhejiang, China
- Cancer Center, Zhejiang University, 310058, Hangzhou, Zhejiang, China
| | - Xin-Hua Feng
- The MOE Key Laboratory of Biosystems Homeostasis & Protection and Zhejiang Provincial Key Laboratory of Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, 310058, Hangzhou, Zhejiang, China.
- Center for Life Sciences, Shaoxing Institute, Zhejiang University, 321000, Shaoxing, Zhejiang, China.
- Cancer Center, Zhejiang University, 310058, Hangzhou, Zhejiang, China.
- The Second Affiliated Hospital, Zhejiang University, Hangzhou, Zhejiang, China.
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4
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Sanchez L, Lensen A, Connor MG, Hamon M, Enninga J, Valenzuela C. Shigella generates distinct IAM subpopulations during epithelial cell invasion to promote efficient intracellular niche formation. Eur J Cell Biol 2024; 103:151381. [PMID: 38183814 DOI: 10.1016/j.ejcb.2023.151381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 12/20/2023] [Accepted: 12/24/2023] [Indexed: 01/08/2024] Open
Abstract
The facultative intracellular pathogen Shigella flexneri invades non-phagocytic epithelial gut cells. Through a syringe-like apparatus called type 3 secretion system, it injects effector proteins into the host cell triggering actin rearrangements leading to its uptake within a tight vacuole, termed the bacterial-containing vacuole (BCV). Simultaneously, Shigella induces the formation of large vesicles around the entry site, which we refer to as infection-associated macropinosomes (IAMs). After entry, Shigella ruptures the BCV and escapes into the host cytosol by disassembling the BCV remnants. Previously, IAM formation has been shown to be required for efficient BCV escape, but the molecular events associated with BCV disassembly have remained unclear. To identify host components required for BCV disassembly, we performed a microscopy-based screen to monitor the recruitment of BAR domain-containing proteins, which are a family of host proteins involved in membrane shaping and sensing (e.g. endocytosis and recycling) during Shigella epithelial cell invasion. We identified endosomal recycling BAR protein Sorting Nexin-8 (SNX8) localized to IAMs in a PI(3)P-dependent manner before BCV disassembly. At least two distinct IAM subpopulations around the BCV were found, either being recycled back to cellular compartments such as the plasma membrane or transitioning to become RAB11A positive "contact-IAMs" involved in promoting BCV rupture. The IAM subpopulation duality was marked by the exclusive recruitment of either SNX8 or RAB11A. Hindering PI(3)P production at the IAMs led to an inhibition of SNX8 recruitment at these compartments and delayed both, the step of BCV rupture time and successful BCV disassembly. Finally, siRNA depletion of SNX8 accelerated BCV rupture and unpeeling of BCV remnants, indicating that SNX8 is involved in controlling the timing of the cytosolic release. Overall, our work sheds light on how Shigella establishes its intracellular niche through the subversion of a specific set of IAMs.
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Affiliation(s)
- Lisa Sanchez
- Institut Pasteur, Université Paris Cité, CNRS UMR3691, Dynamics of Host-Pathogen Interactions Unit, 75015 Paris, France
| | - Arthur Lensen
- Institut Pasteur, Université Paris Cité, CNRS UMR3691, Dynamics of Host-Pathogen Interactions Unit, 75015 Paris, France
| | - Michael G Connor
- Institut Pasteur, Université Paris Cité, Chromatin and Infection Unit, 75015 Paris, France
| | - Mélanie Hamon
- Institut Pasteur, Université Paris Cité, Chromatin and Infection Unit, 75015 Paris, France
| | - Jost Enninga
- Institut Pasteur, Université Paris Cité, CNRS UMR3691, Dynamics of Host-Pathogen Interactions Unit, 75015 Paris, France.
| | - Camila Valenzuela
- Institut Pasteur, Université Paris Cité, CNRS UMR3691, Dynamics of Host-Pathogen Interactions Unit, 75015 Paris, France.
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5
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Kundu S, Jaiswal M, Babu Mullapudi V, Guo J, Kamat M, Basso KB, Guo Z. Investigation of Glycosylphosphatidylinositol (GPI)-Plasma Membrane Interaction in Live Cells and the Influence of GPI Glycan Structure on the Interaction. Chemistry 2024; 30:e202303047. [PMID: 37966101 PMCID: PMC10922586 DOI: 10.1002/chem.202303047] [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: 09/19/2023] [Revised: 11/05/2023] [Accepted: 11/15/2023] [Indexed: 11/16/2023]
Abstract
Glycosylphosphatidylinositols (GPIs) need to interact with other components in the cell membrane to transduce transmembrane signals. A bifunctional GPI probe was employed for photoaffinity-based proximity labelling and identification of GPI-interacting proteins in the cell membrane. This probe contained the entire core structure of GPIs and was functionalized with photoreactive diazirine and clickable alkyne to facilitate its crosslinking with proteins and attachment of an affinity tag. It was disclosed that this probe was more selective than our previously reported probe containing only a part structure of the GPI core for cell membrane incorporation and an improved probe for studying GPI-cell membrane interaction. Eighty-eight unique membrane proteins, many of which are related to GPIs/GPI-anchored proteins, were identified utilizing this probe. The proteomics dataset is a valuable resource for further analyses and data mining to find new GPI-related proteins and signalling pathways. A comparison of these results with those of our previous probe provided direct evidence for the profound impact of GPI glycan structure on its interaction with the cell membrane.
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Affiliation(s)
- Sayan Kundu
- Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
| | - Mohit Jaiswal
- Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
| | | | - Jiatong Guo
- Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
| | - Manasi Kamat
- Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
| | - Kari B Basso
- Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
| | - Zhongwu Guo
- Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
- UF Health Cancer Centre, University of Florida, Gainesville, FL 32611, USA
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6
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Simonetti B, Daly JL, Cullen PJ. Out of the ESCPE room: Emerging roles of endosomal SNX-BARs in receptor transport and host-pathogen interaction. Traffic 2023; 24:234-250. [PMID: 37089068 PMCID: PMC10768393 DOI: 10.1111/tra.12885] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 02/22/2023] [Accepted: 03/28/2023] [Indexed: 04/25/2023]
Abstract
Several functions of the human cell, such as sensing nutrients, cell movement and interaction with the surrounding environment, depend on a myriad of transmembrane proteins and their associated proteins and lipids (collectively termed "cargoes"). To successfully perform their tasks, cargo must be sorted and delivered to the right place, at the right time, and in the right amount. To achieve this, eukaryotic cells have evolved a highly organized sorting platform, the endosomal network. Here, a variety of specialized multiprotein complexes sort cargo into itineraries leading to either their degradation or their recycling to various organelles for further rounds of reuse. A key sorting complex is the Endosomal SNX-BAR Sorting Complex for Promoting Exit (ESCPE-1) that promotes the recycling of an array of cargos to the plasma membrane and/or the trans-Golgi network. ESCPE-1 recognizes a hydrophobic-based sorting motif in numerous cargoes and orchestrates their packaging into tubular carriers that pinch off from the endosome and travel to the target organelle. A wide range of pathogens mimic this sorting motif to hijack ESCPE-1 transport to promote their invasion and survival within infected cells. In other instances, ESCPE-1 exerts restrictive functions against pathogens by limiting their replication and infection. In this review, we discuss ESCPE-1 assembly and functions, with a particular focus on recent advances in the understanding of its role in membrane trafficking, cellular homeostasis and host-pathogen interaction.
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Affiliation(s)
- Boris Simonetti
- Charles River Laboratories, Discovery House, Quays Office ParkConference Avenue, PortisheadBristolUK
| | - James L. Daly
- Department of Infectious DiseasesSchool of Immunology and Microbial Sciences, Guy's Hospital, King's College LondonLondonUK
| | - Peter J. Cullen
- School of Biochemistry, Faculty of Life Sciences, Biomedical Sciences BuildingUniversity of BristolBristolUK
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7
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Shortill SP, Frier MS, Conibear E. You can go your own way: SNX-BAR coat complexes direct traffic at late endosomes. Curr Opin Cell Biol 2022; 76:102087. [DOI: 10.1016/j.ceb.2022.102087] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 03/23/2022] [Accepted: 04/01/2022] [Indexed: 12/20/2022]
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8
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Beck P, Selle B, Madenach L, Jones DTW, Vokuhl C, Gopisetty A, Nabbi A, Brecht IB, Ebinger M, Wegert J, Graf N, Gessler M, Pfister SM, Jäger N. The genomic landscape of pediatric renal cell carcinomas. iScience 2022; 25:104167. [PMID: 35445187 PMCID: PMC9014386 DOI: 10.1016/j.isci.2022.104167] [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: 11/16/2021] [Revised: 03/03/2022] [Accepted: 03/24/2022] [Indexed: 12/08/2022] Open
Abstract
Pediatric renal cell carcinomas (RCC) differ from their adult counterparts not only in histologic subtypes but also in clinical characteristics and outcome. However, the underlying biology is still largely unclear. For this reason, we performed whole-exome and transcriptome sequencing analyses on a cohort of 25 pediatric RCC patients with various histologic subtypes, including 10 MiT family translocation (MiT) and 10 papillary RCCs. In this cohort of pediatric RCC, we find only limited genomic overlap with adult RCC, even within the same histologic subtype. Recurrent somatic mutations in genes not previously reported in RCC were detected, such as in CCDC168, PLEKHA1, VWF, and MAP3K9. Our papillary pediatric RCCs, which represent the largest cohort to date with comprehensive molecular profiling in this age group, appeared as a distinct genomic subtype differing in terms of gene mutations and gene expression patterns not only from MiT-RCC but also from their adult counterparts. WES and RNA-seq of 25 pediatric RCCs with various histologic subtypes Detected only limited genomic overlap with adult RCC Revealed recurrent somatic mutations in genes not previously reported in RCC Discovery of a CRK-PITPNA fusion gene in a pediatric papillary RCC
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Affiliation(s)
- Pengbo Beck
- Hopp Children's Cancer Center Heidelberg (KiTZ) & Division of Pediatric Neurooncology, German Cancer Research Center (DKFZ) and German Cancer Consortium (DKTK), Heidelberg, Germany.,Faculty of Biosciences, Heidelberg University, Heidelberg, Germany
| | - Barbara Selle
- Hopp Children's Cancer Center Heidelberg (KiTZ) & Division of Pediatric Neurooncology, German Cancer Research Center (DKFZ) and German Cancer Consortium (DKTK), Heidelberg, Germany
| | - Lukas Madenach
- Hopp Children's Cancer Center Heidelberg (KiTZ) & Division of Pediatric Neurooncology, German Cancer Research Center (DKFZ) and German Cancer Consortium (DKTK), Heidelberg, Germany.,Faculty of Biosciences, Heidelberg University, Heidelberg, Germany
| | - David T W Jones
- Hopp Children's Cancer Center Heidelberg (KiTZ) & Division of Pediatric Neurooncology, German Cancer Research Center (DKFZ) and German Cancer Consortium (DKTK), Heidelberg, Germany.,Pediatric Glioma Research Group, German Cancer Consortium (DKTK), German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Christian Vokuhl
- Section of Pediatric Pathology, Department of Pathology, University Hospital Bonn, Bonn, Germany
| | - Apurva Gopisetty
- Hopp Children's Cancer Center Heidelberg (KiTZ) & Division of Pediatric Neurooncology, German Cancer Research Center (DKFZ) and German Cancer Consortium (DKTK), Heidelberg, Germany.,Faculty of Biosciences, Heidelberg University, Heidelberg, Germany
| | - Arash Nabbi
- Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
| | - Ines B Brecht
- Department of Pediatric Oncology and Hematology, University Children's Hospital Tübingen, Tübingen, Germany
| | - Martin Ebinger
- Department of Pediatric Oncology and Hematology, University Children's Hospital Tübingen, Tübingen, Germany
| | - Jenny Wegert
- Theodor-Boveri-Institute/Biocenter, Developmental Biochemistry, Würzburg University & Comprehensive Cancer Center Mainfranken, Würzburg, Germany
| | - Norbert Graf
- Department of Pediatric Oncology and Hematology, Saarland University, Homburg, Germany
| | - Manfred Gessler
- Theodor-Boveri-Institute/Biocenter, Developmental Biochemistry, Würzburg University & Comprehensive Cancer Center Mainfranken, Würzburg, Germany
| | - Stefan M Pfister
- Hopp Children's Cancer Center Heidelberg (KiTZ) & Division of Pediatric Neurooncology, German Cancer Research Center (DKFZ) and German Cancer Consortium (DKTK), Heidelberg, Germany.,Department of Pediatric Oncology, Hematology and Immunology, University Hospital Heidelberg, Heidelberg, Germany
| | - Natalie Jäger
- Hopp Children's Cancer Center Heidelberg (KiTZ) & Division of Pediatric Neurooncology, German Cancer Research Center (DKFZ) and German Cancer Consortium (DKTK), Heidelberg, Germany
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9
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Wu C, Lu S, Hu J, Li X, Yao D, Zhang M. Cloning and functional analysis of SNX8 from grass carp (Ctenopharyngodon idellus). FISH & SHELLFISH IMMUNOLOGY 2022; 120:392-401. [PMID: 34920130 DOI: 10.1016/j.fsi.2021.12.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 12/05/2021] [Accepted: 12/09/2021] [Indexed: 06/14/2023]
Abstract
Sorting nexin 8 (SNX8), a member of sorting nexin protein family, plays important roles in endocytosis, endosomal sorting, and innate immune response. To date, a few homologs of SNX8 have been found in fish except in mammals. In this study, a teleost SNX8 cDNA was identified from grass carp (Ctenopharyngodon idellus). CiSNX8 was up-regulated significantly after infection with poly I:C or GCRV. We found that SNX8 was mainly distributed in the endoplasmic reticulum (ER) in CIK cells. Further analysis indicated that CiSNX8 might negatively regulate RLR signaling pathway that is quite distinct from mammalian SNX8. In addition, CiSNX8 could interact with MAVS, STING, TBK1, IRF3 and IRF7. Either wild type CiSNX8 or mutants of N-terminal PX domain (aa 1-245) and C-terminal BAR domain (aa 256-519) could associate with STING. These results suggested that fish SNX8 participated in innate immune response through different molecular mechanisms.
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Affiliation(s)
- Chuxin Wu
- Yuzhang Normal University, Nanchang, 330103, China.
| | - Shina Lu
- Department of Bioscience, College of Life Science, Nanchang University, Nanchang, 330031, China
| | - Jihuan Hu
- Department of Bioscience, College of Life Science, Nanchang University, Nanchang, 330031, China
| | - Xunhang Li
- Yuzhang Normal University, Nanchang, 330103, China
| | - Dong Yao
- Yuzhang Normal University, Nanchang, 330103, China
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10
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Genome-Wide Characterization of PX Domain-Containing Proteins Involved in Membrane Trafficking-Dependent Growth and Pathogenicity of Fusarium graminearum. mBio 2021; 12:e0232421. [PMID: 34933449 PMCID: PMC8689521 DOI: 10.1128/mbio.02324-21] [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] [Indexed: 11/29/2022] Open
Abstract
The Phox homology (PX) domain is a membrane recruitment module that binds to phosphoinositides (PI) mediating the selective sorting and transport of transmembrane proteins, lipids, and other critical cargo molecules via membrane trafficking processes. However, the mechanism of vesicular trafficking mediated by PX domain-containing proteins in phytopathogenic fungi and how this relates to the fungal development and pathogenicity remain unclear. Here, we systematically identified and characterized the functions of PX domain-containing proteins in the plant fungal pathogen Fusarium graminearum. Our data identified 14 PX domain-containing proteins in F. graminearum, all of which were required for plant infection and deoxynivalenol (DON) production, with the exception of FgMvp1 and FgYkr078. Furthermore, all the PX domain-containing proteins showed distinct localization patterns that were limited to the endosomes, vacuolar membrane, endoplasmic reticulum, cytoplasm, and hyphal septa/tips. Remarkably, among these proteins, FgBem1 targeted to surface crescent and septal pores and was retained at the septum pores even after actin constriction during septum development. Further analyses demonstrated that the surface crescent targeting of FgBem1 solely depended on its SH3 domains, while its septum and apex anchoring localization relied on its PX domain, which was also indispensable for reactive oxygen species (ROS) production, sexual development, and pathogenicity in F. graminearum. In summary, our study is the first detailed and comprehensive functional analysis of PX domain-containing proteins in filamentous fungi, and it provides new insight into the mechanism of FgBem1 involved in septum and apex anchorage mediated by its PX domain, which is necessary for sexual development and pathogenicity of F. graminearum.
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11
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Hu Y, He W, Huang Y, Xiang H, Guo J, Che Y, Cheng X, Hu F, Hu M, Ma T, Yu J, Tian H, Tian S, Ji YX, Zhang P, She ZG, Zhang XJ, Huang Z, Yang J, Li H. Fatty Acid Synthase-Suppressor Screening Identifies Sorting Nexin 8 as a Therapeutic Target for NAFLD. Hepatology 2021; 74:2508-2525. [PMID: 34231239 DOI: 10.1002/hep.32045] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 06/21/2021] [Accepted: 06/28/2021] [Indexed: 12/12/2022]
Abstract
BACKGROUND AND AIMS NAFLD is the most prevalent chronic liver disease without any Food and Drug Administration-approved pharmacological intervention in clinic. Fatty acid synthase (FASN) is one of the most attractive targets for NAFLD treatment because of its robust rate-limiting capacity to control hepatic de novo lipogenesis. However, the regulatory mechanisms of FASN in NAFLD and potential therapeutic strategies targeting FASN remain largely unknown. METHODS AND RESULTS Through a systematic interactomics analysis of FASN-complex proteins, we screened and identified sorting nexin 8 (SNX8) as a binding partner of FASN. SNX8 directly bound to FASN and promoted FASN ubiquitination and subsequent proteasomal degradation. We further demonstrated that SNX8 mediated FASN protein degradation by recruiting the E3 ligase tripartite motif containing 28 (TRIM28) and enhancing the TRIM28-FASN interaction. Notably, Snx8 interference in hepatocytes significantly deteriorated lipid accumulation in vitro, whereas SNX8 overexpression markedly blocked hepatocyte lipid deposition. Furthermore, the aggravating effect of Snx8 deletion on NAFLD was validated in vivo as hepatic steatosis and lipogenic pathways in the liver were significantly exacerbated in Snx8-knockout mice compared to wild-type controls. Consistently, hepatocyte-specific overexpression of Snx8 in vivo markedly suppressed high-fat, high-cholesterol diet (HFHC)-induced hepatic steatosis. Notably, the protective effect of SNX8 against NAFLD was largely dependent on FASN suppression. CONCLUSIONS These data indicate that SNX8 is a key suppressor of NAFLD that promotes FASN proteasomal degradation. Targeting the SNX8-FASN axis is a promising strategy for NAFLD prevention and treatment.
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Affiliation(s)
- Yufeng Hu
- College of Life Sciences, Medical Science Research Center, Zhongnan Hospital, Wuhan University, Wuhan, China.,Institute of Model Animal, Wuhan University, Wuhan, China
| | - Wenzhi He
- College of Life Sciences, Medical Science Research Center, Zhongnan Hospital, Wuhan University, Wuhan, China.,Institute of Model Animal, Wuhan University, Wuhan, China.,Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, China
| | - Yongping Huang
- College of Life Sciences, Medical Science Research Center, Zhongnan Hospital, Wuhan University, Wuhan, China.,Institute of Model Animal, Wuhan University, Wuhan, China.,Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, China
| | - Hui Xiang
- Institute of Model Animal, Wuhan University, Wuhan, China.,Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Juan Guo
- College of Life Sciences, Medical Science Research Center, Zhongnan Hospital, Wuhan University, Wuhan, China.,Institute of Model Animal, Wuhan University, Wuhan, China.,Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, China
| | - Yan Che
- Institute of Model Animal, Wuhan University, Wuhan, China.,Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Xu Cheng
- Institute of Model Animal, Wuhan University, Wuhan, China.,Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Fengjiao Hu
- College of Life Sciences, Medical Science Research Center, Zhongnan Hospital, Wuhan University, Wuhan, China.,Institute of Model Animal, Wuhan University, Wuhan, China
| | - Manli Hu
- College of Life Sciences, Medical Science Research Center, Zhongnan Hospital, Wuhan University, Wuhan, China.,Institute of Model Animal, Wuhan University, Wuhan, China
| | - Tengfei Ma
- Institute of Model Animal, Wuhan University, Wuhan, China.,Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Jie Yu
- Institute of Model Animal, Wuhan University, Wuhan, China
| | - Han Tian
- Institute of Model Animal, Wuhan University, Wuhan, China.,Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Song Tian
- Institute of Model Animal, Wuhan University, Wuhan, China.,Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Yan-Xiao Ji
- College of Life Sciences, Medical Science Research Center, Zhongnan Hospital, Wuhan University, Wuhan, China.,Institute of Model Animal, Wuhan University, Wuhan, China
| | - Peng Zhang
- Institute of Model Animal, Wuhan University, Wuhan, China.,Basic Medical School, Wuhan University, Wuhan, China
| | - Zhi-Gang She
- Institute of Model Animal, Wuhan University, Wuhan, China.,Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Xiao-Jing Zhang
- Institute of Model Animal, Wuhan University, Wuhan, China.,Basic Medical School, Wuhan University, Wuhan, China
| | - Zan Huang
- College of Life Sciences, Medical Science Research Center, Zhongnan Hospital, Wuhan University, Wuhan, China.,Institute of Model Animal, Wuhan University, Wuhan, China.,Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, China
| | - Juan Yang
- Institute of Model Animal, Wuhan University, Wuhan, China.,Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Hongliang Li
- College of Life Sciences, Medical Science Research Center, Zhongnan Hospital, Wuhan University, Wuhan, China.,Institute of Model Animal, Wuhan University, Wuhan, China.,Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China.,Basic Medical School, Wuhan University, Wuhan, China
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12
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Grahammer F, Huber TB, Artunc F. Role of mTOR Signaling for Tubular Function and Disease. Physiology (Bethesda) 2021; 36:350-358. [PMID: 34514872 DOI: 10.1152/physiol.00021.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The mechanistic target of rapamycin (mTOR) forms two distinct intracellular multiprotein complexes that control a multitude of intracellular processes linked to metabolism, proliferation, actin cytoskeleton, and survival. Recent studies have identified the importance of these complexes for transport regulation of ions and nutrients along the entire nephron. First reports could link altered activity of these complexes to certain disease entities, i.e. diabetic nephropathy, acute kidney injury or hyperkalemia.
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Affiliation(s)
- Florian Grahammer
- Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Tobias B Huber
- Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Ferruh Artunc
- Department of Internal Medicine, Division of Endocrinology, Diabetology, and Nephrology, University Hospital Tübingen, Tübingen, Germany.,Institute of Diabetes Research and Metabolic Diseases, Helmholtz Center Munich, University Tübingen, Tübingen, Germany.,German Center for Diabetes Research, University Tübingen, Tübingen, Germany
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13
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Suzuki SW, Oishi A, Nikulin N, Jorgensen JR, Baile MG, Emr SD. A PX-BAR protein Mvp1/SNX8 and a dynamin-like GTPase Vps1 drive endosomal recycling. eLife 2021; 10:69883. [PMID: 34524084 PMCID: PMC8504969 DOI: 10.7554/elife.69883] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 09/14/2021] [Indexed: 12/13/2022] Open
Abstract
Membrane protein recycling systems are essential for maintenance of the endosome-lysosome system. In yeast, retromer and Snx4 coat complexes are recruited to the endosomal surface, where they recognize cargos. They sort cargo and deform the membrane into recycling tubules that bud from the endosome and target to the Golgi. Here, we reveal that the SNX-BAR protein, Mvp1, mediates an endosomal recycling pathway that is mechanistically distinct from the retromer and Snx4 pathways. Mvp1 deforms the endosomal membrane and sorts cargos containing a specific sorting motif into a membrane tubule. Subsequently, Mvp1 recruits the dynamin-like GTPase Vps1 to catalyze membrane scission and release of the recycling tubule. Similarly, SNX8, the human homolog of Mvp1, which has been also implicated in Alzheimer’s disease, mediates formation of an endosomal recycling tubule. Thus, we present evidence for a novel endosomal retrieval pathway that is conserved from yeast to humans.
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Affiliation(s)
- Sho W Suzuki
- Weill Institute for Cell and Molecular Biology and Department of Molecular Biology and Genetics, Cornell University, Ithaca, United States
| | - Akihiko Oishi
- Weill Institute for Cell and Molecular Biology and Department of Molecular Biology and Genetics, Cornell University, Ithaca, United States
| | - Nadia Nikulin
- Weill Institute for Cell and Molecular Biology and Department of Molecular Biology and Genetics, Cornell University, Ithaca, United States
| | - Jeff R Jorgensen
- Weill Institute for Cell and Molecular Biology and Department of Molecular Biology and Genetics, Cornell University, Ithaca, United States
| | - Matthew G Baile
- Weill Institute for Cell and Molecular Biology and Department of Molecular Biology and Genetics, Cornell University, Ithaca, United States
| | - Scott D Emr
- Weill Institute for Cell and Molecular Biology and Department of Molecular Biology and Genetics, Cornell University, Ithaca, United States
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14
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Kervin TA, Wiseman BC, Overduin M. Phosphoinositide Recognition Sites Are Blocked by Metabolite Attachment. Front Cell Dev Biol 2021; 9:690461. [PMID: 34368138 PMCID: PMC8340361 DOI: 10.3389/fcell.2021.690461] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Accepted: 06/18/2021] [Indexed: 12/16/2022] Open
Abstract
Membrane readers take part in trafficking and signaling processes by localizing proteins to organelle surfaces and transducing molecular information. They accomplish this by engaging phosphoinositides (PIs), a class of lipid molecules which are found in different proportions in various cellular membranes. The prototypes are the PX domains, which exhibit a range of specificities for PIs. Our meta-analysis indicates that recognition of membranes by PX domains is specifically controlled by modification of lysine and arginine residues including acetylation, hydroxyisobutyrylation, glycation, malonylation, methylation and succinylation of sidechains that normally bind headgroups of phospholipids including organelle-specific PI signals. Such metabolite-modulated residues in lipid binding elements are named MET-stops here to highlight their roles as erasers of membrane reader functions. These modifications are concentrated in the membrane binding sites of half of all 49 PX domains in the human proteome and correlate with phosphoregulatory sites, as mapped using the Membrane Optimal Docking Area (MODA) algorithm. As these motifs are mutated and modified in various cancers and the responsible enzymes serve as potential drug targets, the discovery of MET-stops as a widespread inhibitory mechanism may aid in the development of diagnostics and therapeutics aimed at the readers, writers and erasers of the PI code.
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Affiliation(s)
- Troy A Kervin
- Department of Biochemistry, University of Alberta, Edmonton, AB, Canada
| | - Brittany C Wiseman
- Department of Biochemistry, University of Alberta, Edmonton, AB, Canada.,Molecular and Cellular Biology, MacEwan University, Edmonton, AB, Canada.,SMALP Network, Edmonton, AB, Canada
| | - Michael Overduin
- Department of Biochemistry, University of Alberta, Edmonton, AB, Canada.,SMALP Network, Edmonton, AB, Canada
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15
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Kervin TA, Overduin M. Regulation of the Phosphoinositide Code by Phosphorylation of Membrane Readers. Cells 2021; 10:cells10051205. [PMID: 34069055 PMCID: PMC8156045 DOI: 10.3390/cells10051205] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 05/07/2021] [Accepted: 05/09/2021] [Indexed: 02/07/2023] Open
Abstract
The genetic code that dictates how nucleic acids are translated into proteins is well known, however, the code through which proteins recognize membranes remains mysterious. In eukaryotes, this code is mediated by hundreds of membrane readers that recognize unique phosphatidylinositol phosphates (PIPs), which demark organelles to initiate localized trafficking and signaling events. The only superfamily which specifically detects all seven PIPs are the Phox homology (PX) domains. Here, we reveal that throughout evolution, these readers are universally regulated by the phosphorylation of their PIP binding surfaces based on our analysis of existing and modelled protein structures and phosphoproteomic databases. These PIP-stops control the selective targeting of proteins to organelles and are shown to be key determinants of high-fidelity PIP recognition. The protein kinases responsible include prominent cancer targets, underscoring the critical role of regulated membrane readership.
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16
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Vieira N, Rito T, Correia-Neves M, Sousa N. Sorting Out Sorting Nexins Functions in the Nervous System in Health and Disease. Mol Neurobiol 2021; 58:4070-4106. [PMID: 33931804 PMCID: PMC8280035 DOI: 10.1007/s12035-021-02388-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 04/05/2021] [Indexed: 12/18/2022]
Abstract
Endocytosis is a fundamental process that controls protein/lipid composition of the plasma membrane, thereby shaping cellular metabolism, sensing, adhesion, signaling, and nutrient uptake. Endocytosis is essential for the cell to adapt to its surrounding environment, and a tight regulation of the endocytic mechanisms is required to maintain cell function and survival. This is particularly significant in the central nervous system (CNS), where composition of neuronal cell surface is crucial for synaptic functioning. In fact, distinct pathologies of the CNS are tightly linked to abnormal endolysosomal function, and several genome wide association analysis (GWAS) and biochemical studies have identified intracellular trafficking regulators as genetic risk factors for such pathologies. The sorting nexins (SNXs) are a family of proteins involved in protein trafficking regulation and signaling. SNXs dysregulation occurs in patients with Alzheimer’s disease (AD), Down’s syndrome (DS), schizophrenia, ataxia and epilepsy, among others, establishing clear roles for this protein family in pathology. Interestingly, restoration of SNXs levels has been shown to trigger synaptic plasticity recovery in a DS mouse model. This review encompasses an historical and evolutionary overview of SNXs protein family, focusing on its organization, phyla conservation, and evolution throughout the development of the nervous system during speciation. We will also survey SNXs molecular interactions and highlight how defects on SNXs underlie distinct pathologies of the CNS. Ultimately, we discuss possible strategies of intervention, surveying how our knowledge about the fundamental processes regulated by SNXs can be applied to the identification of novel therapeutic avenues for SNXs-related disorders.
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Affiliation(s)
- Neide Vieira
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus Gualtar, 4710-057, Braga, Portugal. .,ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal.
| | - Teresa Rito
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus Gualtar, 4710-057, Braga, Portugal.,ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Margarida Correia-Neves
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus Gualtar, 4710-057, Braga, Portugal.,ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Nuno Sousa
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus Gualtar, 4710-057, Braga, Portugal.,ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
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17
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Seaman MNJ. The Retromer Complex: From Genesis to Revelations. Trends Biochem Sci 2021; 46:608-620. [PMID: 33526371 DOI: 10.1016/j.tibs.2020.12.009] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 12/15/2020] [Accepted: 12/17/2020] [Indexed: 12/13/2022]
Abstract
The retromer complex has a well-established role in endosomal protein sorting, being necessary for maintaining the dynamic localisation of hundreds of membrane proteins that traverse the endocytic system. Retromer function and dysfunction is linked with neurodegenerative diseases, including Alzheimer's and Parkinson's disease, and many pathogens, both viral and bacterial, exploit or interfere in retromer function for their own ends. In this review, the history of retromer is distilled into a concentrated form that spans the identification of retromer to recent discoveries that have shed new light on how retromer functions in endosomal protein sorting and why retromer is increasingly being viewed as a potential therapeutic target in neurodegenerative disease.
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Affiliation(s)
- Matthew N J Seaman
- University of Cambridge, Cambridge Institute for Medical Research, The Keith Peters Building, Cambridge Biomedical Campus, Cambridge, CB2 0XY, UK.
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18
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Hanley SE, Cooper KF. Sorting Nexins in Protein Homeostasis. Cells 2020; 10:cells10010017. [PMID: 33374212 PMCID: PMC7823608 DOI: 10.3390/cells10010017] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 12/15/2020] [Accepted: 12/18/2020] [Indexed: 12/11/2022] Open
Abstract
Protein homeostasis is maintained by removing misfolded, damaged, or excess proteins and damaged organelles from the cell by three major pathways; the ubiquitin-proteasome system, the autophagy-lysosomal pathway, and the endo-lysosomal pathway. The requirement for ubiquitin provides a link between all three pathways. Sorting nexins are a highly conserved and diverse family of membrane-associated proteins that not only traffic proteins throughout the cells but also provide a second common thread between protein homeostasis pathways. In this review, we will discuss the connections between sorting nexins, ubiquitin, and the interconnected roles they play in maintaining protein quality control mechanisms. Underlying their importance, genetic defects in sorting nexins are linked with a variety of human diseases including neurodegenerative, cardiovascular diseases, viral infections, and cancer. This serves to emphasize the critical roles sorting nexins play in many aspects of cellular function.
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19
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Yang L, Tan W, Yang X, You Y, Wang J, Wen G, Zhong J. Sorting nexins: A novel promising therapy target for cancerous/neoplastic diseases. J Cell Physiol 2020; 236:3317-3335. [PMID: 33090492 DOI: 10.1002/jcp.30093] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 09/18/2020] [Accepted: 09/22/2020] [Indexed: 12/17/2022]
Abstract
Sorting nexins (SNXs) are a diverse group of cytoplasmic- and membrane-associated phosphoinositide-binding proteins containing the PX domain proteins. The function of SNX proteins in regulating intracellular protein trafficking consists of endocytosis, endosomal sorting, and endosomal signaling. Dysfunctions of SNX proteins are demonstrated to be involved in several cancerous/neoplastic diseases. Here, we review the accumulated evidence of the molecular structure and biological function of SNX proteins and discuss the regulatory role of SNX proteins in distinct cancerous/neoplastic diseases. SNX family proteins may be a valuable potential biomarker and therapeutic strategy for diagnostics and treatment of cancerous/neoplastic diseases.
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Affiliation(s)
- Lu Yang
- Hunan Province Key Laboratory of Tumor Cellular & Molecular Pathology, Cancer Research Institute, University of South China, Hengyang, Hunan, China
- Institute of Clinical Medicine, the First Affiliated Hospital of University of South China, Hengyang, Hunan, China
| | - Weihua Tan
- Institute of Clinical Medicine, the First Affiliated Hospital of University of South China, Hengyang, Hunan, China
- Emergency Department, the First Affiliated Hospital of University of South China, Hengyang, Hunan, China
| | - Xinzhi Yang
- Hunan Province Key Laboratory of Tumor Cellular & Molecular Pathology, Cancer Research Institute, University of South China, Hengyang, Hunan, China
- Institute of Clinical Medicine, the First Affiliated Hospital of University of South China, Hengyang, Hunan, China
| | - Yong You
- Research Lab of Translational Medicine, Hengyang Medical College, University of South China, Hengyang, Hunan, China
| | - Jing Wang
- Research Lab of Translational Medicine, Hengyang Medical College, University of South China, Hengyang, Hunan, China
| | - Gebo Wen
- Hunan Province Key Laboratory of Tumor Cellular & Molecular Pathology, Cancer Research Institute, University of South China, Hengyang, Hunan, China
- Institute of Clinical Medicine, the First Affiliated Hospital of University of South China, Hengyang, Hunan, China
| | - Jing Zhong
- Hunan Province Key Laboratory of Tumor Cellular & Molecular Pathology, Cancer Research Institute, University of South China, Hengyang, Hunan, China
- Institute of Clinical Medicine, the First Affiliated Hospital of University of South China, Hengyang, Hunan, China
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20
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Sun D, Varlakhanova NV, Tornabene BA, Ramachandran R, Zhang P, Ford MGJ. The cryo-EM structure of the SNX-BAR Mvp1 tetramer. Nat Commun 2020; 11:1506. [PMID: 32198400 PMCID: PMC7083883 DOI: 10.1038/s41467-020-15110-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 02/11/2020] [Indexed: 12/22/2022] Open
Abstract
Sorting nexins (SNX) are a family of PX domain-containing proteins with pivotal roles in trafficking and signaling. SNX-BARs, which also have a curvature-generating Bin/Amphiphysin/Rvs (BAR) domain, have membrane-remodeling functions, particularly at the endosome. The minimal PX-BAR module is a dimer mediated by BAR-BAR interactions. Many SNX-BAR proteins, however, additionally have low-complexity N-terminal regions of unknown function. Here, we present the cryo-EM structure of the full-length SNX-BAR Mvp1, which is an autoinhibited tetramer. The tetramer is a dimer of dimers, wherein the membrane-interacting BAR surfaces are sequestered and the PX lipid-binding sites are occluded. The N-terminal low-complexity region of Mvp1 is essential for tetramerization. Mvp1 lacking its N-terminus is dimeric and exhibits enhanced membrane association. Membrane binding and remodeling by Mvp1 therefore requires unmasking of the PX and BAR domain lipid-interacting surfaces. This work reveals a tetrameric configuration of a SNX-BAR protein that provides critical insight into SNX-BAR function and regulation.
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Affiliation(s)
- Dapeng Sun
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15261, USA
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15260, USA
| | - Natalia V Varlakhanova
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15261, USA
| | - Bryan A Tornabene
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15261, USA
| | - Rajesh Ramachandran
- Department of Physiology & Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Peijun Zhang
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15260, USA.
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, OX3 7BN, UK.
- Electron Bio-Imaging Centre, Diamond Light Sources, Harwell Science and Innovation Campus, Didcot, OX11 0DE, UK.
| | - Marijn G J Ford
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15261, USA.
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21
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High Expression of TTYH3 is Related to Poor Clinical Outcomes in Human Gastric Cancer. J Clin Med 2019; 8:jcm8111762. [PMID: 31652813 PMCID: PMC6912211 DOI: 10.3390/jcm8111762] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 10/21/2019] [Accepted: 10/22/2019] [Indexed: 12/13/2022] Open
Abstract
Ion channels play important roles in regulating various cellular processes and malignant transformation. Expressions of some chloride channels have been suggested to be associated with patient survival in gastric cancer (GC). However, little is known about the expression and function of TTYH3, a gene encoding a chloride ion channel, in cancer progression. Here, we comprehensively analyzed the expression of TTYH3 and its clinical outcome in GC using publicly available cancer gene expression and patient survival data through various databases. We examined the differences of TTYH3 expression between cancers and their normal tissues using the Oncomine, UALCAN, and GEO (Gene Expression Omnibus) databases. TTYH3 expression was investigated from immunohistochemistry images using the Human Protein Atlas database. Copy number alterations and mutations of TTYH3 were analyzed using cBioPortal. The co-expression profile of TTYH3 in GC was revealed using Oncomine. The gene ontology and pathway analyses were done using those co-expressed genes via the Enrichr tool to explore the predicted signaling pathways in GC. TTYH3 mRNA and protein levels in GC were significantly greater than those in normal tissue. Kaplan–Meier analysis revealed the upregulation of TTYH3 expression, which was significantly correlated with worse patient survival. Collectively, our data suggest that TTYH3 might be a potential prognostic marker for GC patients.
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22
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Xie Y, Niu M, Ji C, Huang TY, Zhang C, Tian Y, Shi Z, Wang C, Zhao Y, Luo H, Can D, Xu H, Zhang YW, Zhang X. SNX8 Enhances Non-amyloidogenic APP Trafficking and Attenuates Aβ Accumulation and Memory Deficits in an AD Mouse. Front Cell Neurosci 2019; 13:410. [PMID: 31551717 PMCID: PMC6743354 DOI: 10.3389/fncel.2019.00410] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Accepted: 08/26/2019] [Indexed: 12/13/2022] Open
Abstract
Dysregulation of various APP trafficking components in the endosome has been previously implicated in Alzheimer’s disease (AD). Although single nucleotide polymorphisms within the gene locus encoding the endosomal component, SNX8 have been previously associated with AD, how SNX8 levels are altered and its contribution to AD onset is currently unknown. Here, we observe decreased expression of SNX8 in human AD and AD mouse brain. SNX8 predominantly localized to early and late endosomes, where SNX8 overexpression enhanced total APP levels, cell surface APP distribution and consequent soluble APPα cleavage. SNX8 depletion resulted in elevated β-amyloid (Aβ) levels, while SNX8 overexpression reduced Aβ levels in cells and in an APP/PS1 AD mouse model. Importantly, SNX8 overexpression rescued cognitive impairment in APP/PS1 mice. Together, these results implicate a neuroprotective role for SNX8 in enhancing non-amyloidogenic APP trafficking and processing pathways. Given that endosomal dysfunction is an early event in AD, restoration of dysfunctional endosomal components such as SNX8 may be beneficial in future therapeutic strategies.
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Affiliation(s)
- Yongzhuang Xie
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Pharmaceutical Sciences, School of Medicine, Xiamen University, Xiamen, China
| | - Mengxi Niu
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Pharmaceutical Sciences, School of Medicine, Xiamen University, Xiamen, China
| | - Chengxiang Ji
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Pharmaceutical Sciences, School of Medicine, Xiamen University, Xiamen, China
| | - Timothy Y Huang
- Neuroscience Initiative, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, United States
| | - Cuilin Zhang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Pharmaceutical Sciences, School of Medicine, Xiamen University, Xiamen, China.,The United Innovation of Mengchao Hepatobiliary Technology Key Laboratory of Fujian Province, Mengchao Hepatobiliary Hospital of Fujian Medical University, Fuzhou, China
| | - Ye Tian
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Pharmaceutical Sciences, School of Medicine, Xiamen University, Xiamen, China
| | - Zhun Shi
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Pharmaceutical Sciences, School of Medicine, Xiamen University, Xiamen, China
| | - Chen Wang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Pharmaceutical Sciences, School of Medicine, Xiamen University, Xiamen, China.,Department of Neurology, The First Affiliated Hospital, School of Medicine, Xiamen University, Xiamen, China
| | - Yingjun Zhao
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Pharmaceutical Sciences, School of Medicine, Xiamen University, Xiamen, China
| | - Hong Luo
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Pharmaceutical Sciences, School of Medicine, Xiamen University, Xiamen, China
| | - Dan Can
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Pharmaceutical Sciences, School of Medicine, Xiamen University, Xiamen, China
| | - Huaxi Xu
- Neuroscience Initiative, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, United States
| | - Yun-Wu Zhang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Pharmaceutical Sciences, School of Medicine, Xiamen University, Xiamen, China
| | - Xian Zhang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Pharmaceutical Sciences, School of Medicine, Xiamen University, Xiamen, China
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23
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Tessier A, Callier P, LeMeur N, Frebourg T, Sabourin JC, Patrier S. Postmortem Diagnosis of Heart-hand Syndrome Associated With a 7p22.1p22.3 Deletion in a 16-week-old Fetus. Pediatr Dev Pathol 2019; 22:146-151. [PMID: 30193563 DOI: 10.1177/1093526618799293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
We report a male fetus with a 6.8 Mb deletion on chromosome 7p22.1p22.3 at 16 weeks of gestation. The fetus presented a heart-hand syndrome with great artery malposition, bilateral radial ray deficiency, a single pelvic kidney, and growth retardation. This deletion involves a minimal deleted region for cardiac malformation and the RAC1 gene, previously described in limb anomalies in mice. This fetus is the third human case with limb defects and RAC1 deletion.
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Affiliation(s)
- Aude Tessier
- 1 Inserm U1079, Centre Normand de Génomique Médicale et Médecine Personnalisée et Service de Génétique, CHU Charles Nicolle, Rouen, France.,2 Service d'anatomopathologie, CHU Charles Nicolle, Rouen, France
| | - Patrick Callier
- 3 Service de Cytogénétique, Pole Technique et Biologie, CHU Dijon, Dijon, France
| | - Nathalie LeMeur
- 1 Inserm U1079, Centre Normand de Génomique Médicale et Médecine Personnalisée et Service de Génétique, CHU Charles Nicolle, Rouen, France
| | - Thierry Frebourg
- 1 Inserm U1079, Centre Normand de Génomique Médicale et Médecine Personnalisée et Service de Génétique, CHU Charles Nicolle, Rouen, France
| | | | - Sophie Patrier
- 2 Service d'anatomopathologie, CHU Charles Nicolle, Rouen, France
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24
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Naslavsky N, Caplan S. The enigmatic endosome - sorting the ins and outs of endocytic trafficking. J Cell Sci 2018; 131:131/13/jcs216499. [PMID: 29980602 DOI: 10.1242/jcs.216499] [Citation(s) in RCA: 202] [Impact Index Per Article: 33.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The early endosome (EE), also known as the sorting endosome (SE) is a crucial station for the sorting of cargoes, such as receptors and lipids, through the endocytic pathways. The term endosome relates to the receptacle-like nature of this organelle, to which endocytosed cargoes are funneled upon internalization from the plasma membrane. Having been delivered by the fusion of internalized vesicles with the EE or SE, cargo molecules are then sorted to a variety of endocytic pathways, including the endo-lysosomal pathway for degradation, direct or rapid recycling to the plasma membrane, and to a slower recycling pathway that involves a specialized form of endosome known as a recycling endosome (RE), often localized to the perinuclear endocytic recycling compartment (ERC). It is striking that 'the endosome', which plays such essential cellular roles, has managed to avoid a precise description, and its characteristics remain ambiguous and heterogeneous. Moreover, despite the rapid advances in scientific methodologies, including breakthroughs in light microscopy, overall, the endosome remains poorly defined. This Review will attempt to collate key characteristics of the different types of endosomes and provide a platform for discussion of this unique and fascinating collection of organelles. Moreover, under-developed, poorly understood and important open questions will be discussed.
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Affiliation(s)
- Naava Naslavsky
- The Department of Biochemistry and Molecular Biology, The University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Steve Caplan
- The Department of Biochemistry and Molecular Biology, The University of Nebraska Medical Center, Omaha, NE 68198, USA .,The Fred and Pamela Buffett Cancer Center, The University of Nebraska Medical Center, Omaha, NE 68198, USA
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25
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Mukilan M, Rajathei DM, Jeyaraj E, Kayalvizhi N, Rajan KE. MiR-132 regulated olfactory bulb proteins linked to olfactory learning in greater short-nosed fruit bat Cynopterus sphinx. Gene 2018; 671:10-20. [PMID: 29859284 DOI: 10.1016/j.gene.2018.05.107] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 05/11/2018] [Accepted: 05/29/2018] [Indexed: 12/21/2022]
Abstract
Earlier, we showed that micro RNA-132 (miR-132) regulate the immediate early genes (IEGs) in the olfactory bulb (OB) of fruit bat Cynopterus sphinx during olfactory learning. This study was designed to examine whether the miR-132 regulate other proteins in OB during olfactory learning. To test this, miR-132 anti-sense oligodeoxynucleotide (AS-ODN) was delivered to the OB and then trained to novel odor. The 2-dimensional gel electrophoresis analysis showed that inhibition of miR-132 altered olfactory training induced expression of 321 proteins. Further, liquid chromatography-mass spectrometry (LC-MS/MS) analysis reveals the identity of differently expressed proteins such as phosphoribosyl transferase domain containing protein (PRTFDC 1), Sorting nexin-8 (SNX8), Creatine kinase B-type (CKB) and Annexin A11 (ANX A11). Among them PRTFDC 1 showing 189 matching peptides with highest sequence coverage (67.0%) and protein-protein interaction analysis showed that PRTFDC 1 is a homolog of hypoxanthine phosphoribosyltransferase-1 (HPRT-1). Subsequent immunohistochemical analysis (IHC) showed that inhibition of miR-132 down-regulated HPRT expression in OB of C. sphinx. In addition, western blot analysis depicts that HPRT, serotonin transporter (SERT), N-methyl-d-asparate (NMDA) receptors (2A,B) were down-regulated, but not altered in OB of non-sense oligodeoxynucleotide (NS-ODN) infused groups. These analyses suggest that miR-132 regulates the process of olfactory learning and memory formation through SERT and NMDA receptors signalling, which is possibly associated with the PRTFDC1-HPRT interaction.
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Affiliation(s)
- Murugan Mukilan
- Behavioural Neuroscience Laboratory, Department of Animal Science, School of Life Sciences, Bharathidasan University, Tiruchirappalli, India
| | - David Mary Rajathei
- Department of Bioinformatics, School of Life Sciences, Bharathidasan University, Tiruchirappalli, India
| | - Edwin Jeyaraj
- Behavioural Neuroscience Laboratory, Department of Animal Science, School of Life Sciences, Bharathidasan University, Tiruchirappalli, India
| | | | - Koilmani Emmanuvel Rajan
- Behavioural Neuroscience Laboratory, Department of Animal Science, School of Life Sciences, Bharathidasan University, Tiruchirappalli, India.
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26
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SNX8 mediates IFNγ-triggered noncanonical signaling pathway and host defense against Listeria monocytogenes. Proc Natl Acad Sci U S A 2017; 114:13000-13005. [PMID: 29180417 DOI: 10.1073/pnas.1713462114] [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] [Indexed: 12/20/2022] Open
Abstract
IFNγ is a cytokine that plays a key role in host defense against intracellular pathogens. In addition to the canonical JAK-STAT1 pathway, IFNγ also activates an IKKβ-mediated noncanonical signaling pathway that is essential for induction of a subset of downstream effector genes. The molecular mechanisms and functional significance of this IFNγ-triggered noncanonical pathway remains enigmatic. Here, we identified sorting nexin 8 (SNX8) as an important component of the IFNγ-triggered noncanonical signaling pathway. SNX8-deficiency impaired IFNγ-triggered induction of a subset of downstream genes. Snx8-/- mice infected with Listeria monocytogenes exhibited lower serum cytokine levels and higher bacterial loads in the livers and spleens, resulting in higher lethality. Mechanistically, SNX8 interacted with JAK1 and IKKβ and promoted their association. IFNγ induced JAK1-mediated phosphorylation of SNX8 at Tyr95 and Tyr126, which promoted the recruitment of IKKβ to the JAK1 complex. SNX8-deficiency impaired IFNγ-induced oligomerization and autophosphorylation of IKKβ at Ser177, which is critical for selective induction of downstream genes. Our findings suggest that SNX8 acts as a link for IFNγ-triggered noncanonical signaling pathway, which induces a subset of downstream genes important for host defense against L. monocytogenes infection.
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27
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Grahammer F, Ramakrishnan SK, Rinschen MM, Larionov AA, Syed M, Khatib H, Roerden M, Sass JO, Helmstaedter M, Osenberg D, Kühne L, Kretz O, Wanner N, Jouret F, Benzing T, Artunc F, Huber TB, Theilig F. mTOR Regulates Endocytosis and Nutrient Transport in Proximal Tubular Cells. J Am Soc Nephrol 2016; 28:230-241. [PMID: 27297946 DOI: 10.1681/asn.2015111224] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 05/14/2016] [Indexed: 01/03/2023] Open
Abstract
Renal proximal tubular cells constantly recycle nutrients to ensure minimal loss of vital substrates into the urine. Although most of the transport mechanisms have been discovered at the molecular level, little is known about the factors regulating these processes. Here, we show that mTORC1 and mTORC2 specifically and synergistically regulate PTC endocytosis and transport processes. Using a conditional mouse genetic approach to disable nonredundant subunits of mTORC1, mTORC2, or both, we showed that mice lacking mTORC1 or mTORC1/mTORC2 but not mTORC2 alone develop a Fanconi-like syndrome of glucosuria, phosphaturia, aminoaciduria, low molecular weight proteinuria, and albuminuria. Interestingly, proteomics and phosphoproteomics of freshly isolated kidney cortex identified either reduced expression or loss of phosphorylation at critical residues of different classes of specific transport proteins. Functionally, this resulted in reduced nutrient transport and a profound perturbation of the endocytic machinery, despite preserved absolute expression of the main scavenger receptors, MEGALIN and CUBILIN. Our findings highlight a novel mTOR-dependent regulatory network for nutrient transport in renal proximal tubular cells.
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Affiliation(s)
- Florian Grahammer
- Department of Medicine IV, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Suresh K Ramakrishnan
- Institute of Anatomy, Department of Medicine, University of Fribourg, Fribourg, Switzerland
| | - Markus M Rinschen
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Alexey A Larionov
- Institute of Anatomy, Department of Medicine, University of Fribourg, Fribourg, Switzerland
| | - Maryam Syed
- Institute of Anatomy, Department of Medicine, University of Fribourg, Fribourg, Switzerland
| | - Hazim Khatib
- Department of Medical IV, Sektion Nieren- und Hochdruckkrankheiten, University of Tübingen, Tübingen, Germany
| | - Malte Roerden
- Department of Medical IV, Sektion Nieren- und Hochdruckkrankheiten, University of Tübingen, Tübingen, Germany
| | - Jörn Oliver Sass
- Bioanalytics and Biochemistry, Department of Natural Sciences, Bonn Rhein Sieg University of Applied Sciences, Rheinbach, Germany.,Division of Clinical Chemistry and Biochemistry and Children's Research Centre, University Children's Hospital Zürich, Zurich, Switzerland
| | - Martin Helmstaedter
- Department of Medicine IV, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Dorothea Osenberg
- Department of Medicine IV, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Lucas Kühne
- Department of Medicine IV, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Oliver Kretz
- Department of Medicine IV, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Nicola Wanner
- Department of Medicine IV, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Francois Jouret
- Groupe Interdisciplinaire de Génoprotéomique Appliquée, Cardiovascular Sciences, University of Liège, Liege, Belgium; and
| | - Thomas Benzing
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Ferruh Artunc
- Department of Medical IV, Sektion Nieren- und Hochdruckkrankheiten, University of Tübingen, Tübingen, Germany
| | - Tobias B Huber
- Department of Medicine IV, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany; .,BIOSS, Centre for Biological Signalling Studies and.,FRIAS, Freiburg Institute for Advanced Studies and ZBSA, Center for Biological System Analysis, Albert Ludwigs University of Freiburg, Freiburg, Germany
| | - Franziska Theilig
- Institute of Anatomy, Department of Medicine, University of Fribourg, Fribourg, Switzerland;
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28
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Upadhyay S, Xu X, Lowry D, Jackson JC, Roberson RW, Lin X. Subcellular Compartmentalization and Trafficking of the Biosynthetic Machinery for Fungal Melanin. Cell Rep 2016; 14:2511-8. [PMID: 26972005 DOI: 10.1016/j.celrep.2016.02.059] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Revised: 01/08/2016] [Accepted: 02/10/2016] [Indexed: 12/22/2022] Open
Abstract
Protection by melanin depends on its subcellular location. Although most filamentous fungi synthesize melanin via a polyketide synthase pathway, where and how melanin biosynthesis occurs and how it is deposited as extracellular granules remain elusive. Using a forward genetic screen in the pathogen Aspergillus fumigatus, we find that mutations in an endosomal sorting nexin abolish melanin cell-wall deposition. We find that all enzymes involved in the early steps of melanin biosynthesis are recruited to endosomes through a non-conventional secretory pathway. In contrast, late melanin enzymes accumulate in the cell wall. Such subcellular compartmentalization of the melanin biosynthetic machinery occurs in both A. fumigatus and A. nidulans. Thus, fungal melanin biosynthesis appears to be initiated in endosomes with exocytosis leading to melanin extracellular deposition, much like the synthesis and trafficking of mammalian melanin in endosomally derived melanosomes.
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Affiliation(s)
- Srijana Upadhyay
- Department of Biology, Texas A&M University, College Station, TX 77843, USA
| | - Xinping Xu
- Department of Biology, Texas A&M University, College Station, TX 77843, USA
| | - David Lowry
- School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA
| | - Jennifer C Jackson
- Department of Biology, Texas A&M University, College Station, TX 77843, USA
| | - Robert W Roberson
- School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA
| | - Xiaorong Lin
- Department of Biology, Texas A&M University, College Station, TX 77843, USA.
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29
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Li C, Ma W, Yin S, Liang X, Shu X, Pei D, Egan TM, Huang J, Pan A, Li Z. Sorting Nexin 11 Regulates Lysosomal Degradation of Plasma Membrane TRPV3. Traffic 2016; 17:500-14. [DOI: 10.1111/tra.12379] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Revised: 01/21/2016] [Accepted: 01/21/2016] [Indexed: 12/15/2022]
Affiliation(s)
- Caiyue Li
- Key Laboratory of Regenerative Biology, Chinese Academy of Sciences and Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine; Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences; Guangzhou China
| | - Wenbo Ma
- Key Laboratory of Regenerative Biology, Chinese Academy of Sciences and Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine; Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences; Guangzhou China
| | - Shikui Yin
- Key Laboratory of Regenerative Biology, Chinese Academy of Sciences and Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine; Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences; Guangzhou China
| | - Xin Liang
- Key Laboratory of Regenerative Biology, Chinese Academy of Sciences and Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine; Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences; Guangzhou China
| | - Xiaodong Shu
- Key Laboratory of Regenerative Biology, Chinese Academy of Sciences and Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine; Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences; Guangzhou China
| | - Duanqing Pei
- Key Laboratory of Regenerative Biology, Chinese Academy of Sciences and Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine; Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences; Guangzhou China
| | - Terrance M. Egan
- Pharmacological and Physiological Science, School of Medicine; Saint Louis University; St. Louis MO USA
| | - Jufang Huang
- Department of Anatomy and Neurobiology, Xiangya School of Medicine; Central South University; Changsha China
| | - Aihua Pan
- Department of Anatomy and Neurobiology, Xiangya School of Medicine; Central South University; Changsha China
| | - Zhiyuan Li
- Key Laboratory of Regenerative Biology, Chinese Academy of Sciences and Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine; Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences; Guangzhou China
- Department of Anatomy and Neurobiology, Xiangya School of Medicine; Central South University; Changsha China
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30
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Abstract
The evolutionarily conserved endosomal retromer complex rescues transmembrane proteins from the lysosomal degradative pathway and facilitates their recycling to other cellular compartments. Retromer functions in conjunction with numerous associated proteins, including select members of the sorting nexin (SNX) family. In the present article, we review the molecular architecture and cellular roles of retromer and its various functional partners. The endosomal network is a crucial hub in the trafficking of proteins through the cellular endomembrane system. Transmembrane proteins, here termed cargos, enter endosomes by endocytosis from the plasma membrane or by trafficking from the trans-Golgi network (TGN). Endosomal cargo proteins face one of the two fates: retention in the endosome, leading ultimately to lysosomal degradation or export from the endosome for reuse ('recycling'). The balance of protein degradation and recycling is crucial to cellular homoeostasis; inappropriate sorting of proteins to either fate leads to cellular dysfunction. Retromer is an endosome-membrane-associated protein complex central to the recycling of many cargo proteins from endosomes, both to the TGN and the plasma membrane (and other specialized compartments, e.g. lysosome-related organelles). Retromer function is reliant on a number of proteins from the SNX family. In the present article, we discuss this inter-relationship and how defects in retromer function are increasingly being linked with human disease.
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31
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Geldanamycin Enhances Retrograde Transport of Shiga Toxin in HEp-2 Cells. PLoS One 2015; 10:e0129214. [PMID: 26017782 PMCID: PMC4445914 DOI: 10.1371/journal.pone.0129214] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Accepted: 05/06/2015] [Indexed: 12/22/2022] Open
Abstract
The heat shock protein 90 (Hsp90) inhibitor geldanamycin (GA) has been shown to alter endosomal sorting, diverting cargo destined for the recycling pathway into the lysosomal pathway. Here we investigated whether GA also affects the sorting of cargo into the retrograde pathway from endosomes to the Golgi apparatus. As a model cargo we used the bacterial toxin Shiga toxin, which exploits the retrograde pathway as an entry route to the cytosol. Indeed, GA treatment of HEp-2 cells strongly increased the Shiga toxin transport to the Golgi apparatus. The enhanced Golgi transport was not due to increased endocytic uptake of the toxin or perturbed recycling, suggesting that GA selectively enhances endosomal sorting into the retrograde pathway. Moreover, GA activated p38 and both inhibitors of p38 or its substrate MK2 partially counteracted the GA-induced increase in Shiga toxin transport. Thus, our data suggest that GA-induced p38 and MK2 activation participate in the increased Shiga toxin transport to the Golgi apparatus.
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32
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Bergan J, Skotland T, Lingelem ABD, Simm R, Spilsberg B, Lindbäck T, Sylvänne T, Simolin H, Ekroos K, Sandvig K. The ether lipid precursor hexadecylglycerol protects against Shiga toxins. Cell Mol Life Sci 2014; 71:4285-300. [PMID: 24740796 PMCID: PMC11113769 DOI: 10.1007/s00018-014-1624-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Revised: 03/12/2014] [Accepted: 04/01/2014] [Indexed: 11/24/2022]
Abstract
Shiga toxin-producing Escherichia coli bacteria cause hemorrhagic colitis and hemolytic uremic syndrome in humans. Currently, only supportive treatment is available for diagnosed patients. We show here that 24-h pretreatment with an ether lipid precursor, the alkylglycerol sn-1-O-hexadecylglycerol (HG), protects HEp-2 cells against Shiga toxin and Shiga toxin 2. Also the endothelial cell lines HMEC-1 and HBMEC are protected against Shiga toxins after HG pretreatment. In contrast, the corresponding acylglycerol, DL-α-palmitin, has no effect on Shiga toxicity. Although HG treatment provides a strong protection (~30 times higher IC₅₀) against Shiga toxin, only a moderate reduction in toxin binding was observed, suggesting that retrograde transport of the toxin from the plasma membrane to the cytosol is perturbed. Furthermore, endocytosis of Shiga toxin and retrograde sorting from endosomes to the Golgi apparatus remain intact, but transport from the Golgi to the endoplasmic reticulum is inhibited by HG treatment. As previously described, HG reduces the total level of all quantified glycosphingolipids to 50-70% of control, including the Shiga toxin receptor globotriaosylceramide (Gb3), in HEp-2 cells. In accordance with this, we find that interfering with Gb3 biosynthesis by siRNA-mediated knockdown of Gb3 synthase for 24 h causes a similar cytotoxic protection and only a moderate reduction in toxin binding (to 70% of control cells). Alkylglycerols, including HG, have been administered to humans for investigation of therapeutic roles in disorders where ether lipid biosynthesis is deficient, as well as in cancer therapy. Further studies may reveal if HG can also have a therapeutic potential in Shiga toxin-producing E. coli infections.
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Affiliation(s)
- Jonas Bergan
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway
- Department of Biochemistry, Institute for Cancer Research, The Norwegian Radium Hospital, Oslo University Hospital, Montebello, 0379 Oslo, Norway
- Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo, Norway
| | - Tore Skotland
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway
- Department of Biochemistry, Institute for Cancer Research, The Norwegian Radium Hospital, Oslo University Hospital, Montebello, 0379 Oslo, Norway
| | - Anne Berit Dyve Lingelem
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway
- Department of Biochemistry, Institute for Cancer Research, The Norwegian Radium Hospital, Oslo University Hospital, Montebello, 0379 Oslo, Norway
| | - Roger Simm
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway
- Department of Biochemistry, Institute for Cancer Research, The Norwegian Radium Hospital, Oslo University Hospital, Montebello, 0379 Oslo, Norway
| | - Bjørn Spilsberg
- Section of Bacteriology-Food and GMO, Norwegian Veterinary Institute, Oslo, Norway
| | - Toril Lindbäck
- Department of Food Safety and Infection Biology, Norwegian School of Veterinary Science, Oslo, Norway
| | | | | | | | - Kirsten Sandvig
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Oslo, Norway
- Department of Biochemistry, Institute for Cancer Research, The Norwegian Radium Hospital, Oslo University Hospital, Montebello, 0379 Oslo, Norway
- Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo, Norway
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33
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Sierecki E, Stevers LM, Giles N, Polinkovsky ME, Moustaqil M, Mureev S, Johnston WA, Dahmer-Heath M, Skalamera D, Gonda TJ, Gabrielli B, Collins BM, Alexandrov K, Gambin Y. Rapid mapping of interactions between Human SNX-BAR proteins measured in vitro by AlphaScreen and single-molecule spectroscopy. Mol Cell Proteomics 2014; 13:2233-45. [PMID: 24866125 DOI: 10.1074/mcp.m113.037275] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Protein dimerization and oligomerization is commonly used by nature to increase the structural and functional complexity of proteins. Regulated protein assembly is essential to transfer information in signaling, transcriptional, and membrane trafficking events. Here we show that a combination of cell-free protein expression, a proximity based interaction assay (AlphaScreen), and single-molecule fluorescence allow rapid mapping of homo- and hetero-oligomerization of proteins. We have applied this approach to the family of BAR domain-containing sorting nexin (SNX-BAR) proteins, which are essential regulators of membrane trafficking and remodeling in all eukaryotes. Dimerization of BAR domains is essential for creating a concave structure capable of sensing and inducing membrane curvature. We have systematically mapped 144 pairwise interactions between the human SNX-BAR proteins and generated an interaction matrix of preferred dimerization partners for each family member. We find that while nine SNX-BAR proteins are able to form homo-dimers, several including the retromer-associated SNX1, SNX2, and SNX5 require heteromeric interactions for dimerization. SNX2, SNX4, SNX6, and SNX8 show a promiscuous ability to bind other SNX-BAR proteins and we also observe a novel interaction with the SNX3 protein which lacks the BAR domain structure.
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Affiliation(s)
- Emma Sierecki
- From the ‡Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072 Australia
| | - Loes M Stevers
- From the ‡Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072 Australia
| | - Nichole Giles
- From the ‡Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072 Australia
| | - Mark E Polinkovsky
- From the ‡Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072 Australia
| | - Mehdi Moustaqil
- From the ‡Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072 Australia
| | - Sergey Mureev
- From the ‡Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072 Australia
| | - Wayne A Johnston
- From the ‡Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072 Australia
| | - Mareike Dahmer-Heath
- §University of Queensland, Diamantina Institute, Translational Research Institute, Brisbane, Australia
| | - Dubravka Skalamera
- §University of Queensland, Diamantina Institute, Translational Research Institute, Brisbane, Australia
| | - Thomas J Gonda
- ¶School of Pharmacy, The University of Queensland, Brisbane, Australia
| | - Brian Gabrielli
- §University of Queensland, Diamantina Institute, Translational Research Institute, Brisbane, Australia
| | - Brett M Collins
- From the ‡Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072 Australia
| | - Kirill Alexandrov
- From the ‡Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072 Australia;
| | - Yann Gambin
- From the ‡Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072 Australia
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Rendu J, Satre V, Testard H, Devillard F, Vieville G, Fauré J, Amblard F, Jouk PS, Coutton C. 7p22.3 microdeletion disruptingSNX8in a patient presenting with intellectual disability but no tetralogy of Fallot. Am J Med Genet A 2014; 164A:2133-5. [DOI: 10.1002/ajmg.a.36566] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2014] [Accepted: 03/14/2014] [Indexed: 11/09/2022]
Affiliation(s)
- John Rendu
- Département de Biochimie, Biochimie et Génétique Moléculaire; Toxicologie et Pharmacologie; CHU Grenoble Grenoble France
- Université Joseph Fourier; Grenoble France
- Grenoble Institut des Neurosciences; Unité INSERM U836 Grenoble France
| | - Véronique Satre
- Université Joseph Fourier; Grenoble France
- Laboratoire de Génétique Chromosomique, Département de Génétique et Procréation; Hôpital Couple-Enfant; CHU Grenoble Grenoble France
- Université Joseph Fourier, AGIM CNRS FRE3405, Equipe “Andrologie, Génétique et Cancer”; Grenoble France
| | - Hervé Testard
- Service de Pédiatrie et Néonatalogie Centre Hospitalier ALPES LEMAN; Contamine sur Arve France
| | - Francoise Devillard
- Laboratoire de Génétique Chromosomique, Département de Génétique et Procréation; Hôpital Couple-Enfant; CHU Grenoble Grenoble France
| | - Gaëlle Vieville
- Laboratoire de Génétique Chromosomique, Département de Génétique et Procréation; Hôpital Couple-Enfant; CHU Grenoble Grenoble France
| | - Julien Fauré
- Département de Biochimie, Biochimie et Génétique Moléculaire; Toxicologie et Pharmacologie; CHU Grenoble Grenoble France
- Université Joseph Fourier; Grenoble France
- Grenoble Institut des Neurosciences; Unité INSERM U836 Grenoble France
| | - Florence Amblard
- Laboratoire de Génétique Chromosomique, Département de Génétique et Procréation; Hôpital Couple-Enfant; CHU Grenoble Grenoble France
| | - Pierre-Simon Jouk
- Service de Génétique Clinique, Département de Génétique et Procréation; Hôpital Couple-Enfant; CHU Grenoble Grenoble France
| | - Charles Coutton
- Université Joseph Fourier; Grenoble France
- Laboratoire de Génétique Chromosomique, Département de Génétique et Procréation; Hôpital Couple-Enfant; CHU Grenoble Grenoble France
- Université Joseph Fourier, AGIM CNRS FRE3405, Equipe “Andrologie, Génétique et Cancer”; Grenoble France
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35
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van Weering JRT, Cullen PJ. Membrane-associated cargo recycling by tubule-based endosomal sorting. Semin Cell Dev Biol 2014; 31:40-7. [PMID: 24641888 DOI: 10.1016/j.semcdb.2014.03.015] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Revised: 03/09/2014] [Accepted: 03/11/2014] [Indexed: 01/27/2023]
Abstract
The endosome system is a collection of organelles that sort membrane-associated proteins and lipids for lysosomal degradation or recycling back to their target organelle. Recycling cargo is captured in a network of membrane tubules emanating from endosomes where tubular carriers pinch off. These tubules are formed and stabilized through the scaffolding properties of cytosolic Bin/Amphiphysin/Rvs (BAR) proteins that comprise phosphoinositide-detecting moieties, recruiting these proteins to specific endosomal membrane areas. These include the protein family of sorting nexins that remodel endosome membrane into tubules by an evolutionary conserved mechanism of dimerization, local membrane curvature detection/induction and oligomerization. How the formation of such a tubular membrane carrier is coordinated with cargo capture is largely unknown. The tubular structure of the membrane carriers could sequester membrane-bound cargo through an iterative mechanism of geometric sorting. Furthermore, the recent identification of cargo adaptors for the endosome protein sorting complex retromer has expanded the sorting signals that retrieve specific sets of cargo away from lysosomal degradation through distinct membrane trafficking pathways.
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Affiliation(s)
- Jan R T van Weering
- Department of Functional Genomics and Clinical Genetics, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University and VU Medical Center, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands.
| | - Peter J Cullen
- Henry Wellcome Integrated Signalling Laboratories, School of Biochemistry, Medical Sciences Building, University Walk, University of Bristol, Bristol BS8 1TD, United Kingdom
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36
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Chi RJ, Liu J, West M, Wang J, Odorizzi G, Burd CG. Fission of SNX-BAR-coated endosomal retrograde transport carriers is promoted by the dynamin-related protein Vps1. ACTA ACUST UNITED AC 2014; 204:793-806. [PMID: 24567361 PMCID: PMC3941054 DOI: 10.1083/jcb.201309084] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Endosomal sorting and fission machineries act together to produce retrograde transport carriers. Retromer is an endosomal sorting device that orchestrates capture and packaging of cargo into transport carriers coated with sorting nexin BAR domain proteins (SNX-BARs). We report that fission of retromer SNX-BAR–coated tubules from yeast endosomes is promoted by Vps1, a dynamin-related protein that localizes to endosomes decorated by retromer SNX-BARs and Mvp1, a SNX-BAR that is homologous to human SNX8. Mvp1 exhibits potent membrane remodeling activity in vitro, and it promotes association of Vps1 with the endosome in vivo. Retrograde transport carriers bud from the endosome coated by retromer and Mvp1, and cargo export is deficient in mvp1- and vps1-null cells, but with distinct endpoints; cargo export is delayed in mvp1-null cells, but cargo export completely fails in vps1-null cells. The results indicate that Mvp1 promotes Vps1-mediated fission of retromer- and Mvp1-coated tubules that bud from the endosome, revealing a functional link between the endosomal sorting and fission machineries to produce retrograde transport carriers.
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Affiliation(s)
- Richard J Chi
- Department of Cell Biology, Yale School of Medicine, New Haven, CT 06520
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37
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Muirhead G, Dev KK. The expression of neuronal sorting nexin 8 (SNX8) exacerbates abnormal cholesterol levels. J Mol Neurosci 2013; 53:125-34. [PMID: 24362679 DOI: 10.1007/s12031-013-0209-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Accepted: 12/09/2013] [Indexed: 11/30/2022]
Abstract
SNX8 is a PX-BAR domain sub-family of sorting nexins (SNXs), which is reported as a β-amyloid (Aβ) toxicity enhancer and associated with Alzheimer's disease. We have also described SNX8 as a novel activator of the sterol regulatory element binding protein (SREBP) transcription factor, a major regulator of cholesterol homeostasis. In that study, we have showed that SNX8 reduced an insulin-induced gene (INSIG)-dependent block of SREBP-mediated transcription. Here, for the first time, we investigated the expression and function of SNX8 within the CNS. We found that SNX8 was expressed within neurons, but not astrocytes or microglia, with neuronal localisation primarily in the soma. The protein levels of neuronal SNX8 were unchanged in the presence of moderately high cholesterol but were decreased by mevinolin (a cholesterol-lowering statin) and U18666a (which causes cholesterol to accumulate within the lysosome). To determine if SNX8 overexpression alters the levels of cholesterol, we engineered a GFP-SNX8 lentivirus. The overexpression of GFP-SNX8 had no effect on cholesterol in neurons under control conditions or in already strongly altered cholesterol conditions of mevinolin or U18666a. In contrast, in moderately high cholesterol, the overexpression of GFP-SNX8 caused redistribution of cholesterol within neurons creating a phenotype similar to U18666a treatment. Taken together, these data suggest that extreme changes in cholesterol reduce SNX8 expression and that overexpression of SNX8 exacerbates aberrant handling of neuronal cholesterol. This work further supports the role for SNX8 in regulating cholesterol levels, which could be important in understanding its role as an Aβ toxicity enhancer and its association with Alzheimer's disease.
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Affiliation(s)
- Gillian Muirhead
- Molecular Neuropharmacology, Department of Physiology, School of Medicine, Trinity College Dublin, Dublin, Ireland
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38
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Vanzo RJ, Martin MM, Sdano MR, Teta K, Aggarwal V, South ST. SNX8: A candidate gene for 7p22 cardiac malformations including tetralogy of fallot. Am J Med Genet A 2013; 164A:554-6. [PMID: 24311514 DOI: 10.1002/ajmg.a.36242] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Accepted: 08/19/2013] [Indexed: 11/07/2022]
Affiliation(s)
- Rena J Vanzo
- Lineagen, Inc., 423 Wakara Way, Ste 200, Salt Lake City, UT 84108, United States
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39
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Sandvig K, Skotland T, van Deurs B, Klokk TI. Retrograde transport of protein toxins through the Golgi apparatus. Histochem Cell Biol 2013; 140:317-26. [PMID: 23765164 DOI: 10.1007/s00418-013-1111-z] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/01/2013] [Indexed: 12/13/2022]
Abstract
A number of protein toxins from plants and bacteria take advantage of transport through the Golgi apparatus to gain entry into the cytosol where they exert their action. These toxins include the plant toxin ricin, the bacterial Shiga toxins, and cholera toxin. Such toxins bind to lipids or proteins at the cell surface, and they are endocytosed both by clathrin-dependent and clathrin-independent mechanisms. Sorting to the Golgi and retrograde transport to the endoplasmic reticulum (ER) are common to these toxins, but the exact mechanisms turn out to be toxin and cell-type dependent. In the ER, the enzymatically active part is released and then transported into the cytosol, exploiting components of the ER-associated degradation system. In this review, we will discuss transport of different protein toxins, but we will focus on factors involved in entry and sorting of ricin and Shiga toxin into and through the Golgi apparatus.
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Affiliation(s)
- Kirsten Sandvig
- Centre for Cancer Biomedicine, University of Oslo, Oslo, Norway.
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40
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Hunt SD, Townley AK, Danson CM, Cullen PJ, Stephens DJ. Microtubule motors mediate endosomal sorting by maintaining functional domain organization. J Cell Sci 2013; 126:2493-501. [PMID: 23549789 PMCID: PMC3679488 DOI: 10.1242/jcs.122317] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Many microtubule motors have been shown to couple to endosomal membranes. These motors include dynein in addition to many different kinesin family members. Sorting nexins (SNXs) are central to the organization and function of endosomes. These proteins can actively shape endosomal membranes and couple directly or indirectly to the minus-end microtubule motor dynein. Motor proteins acting on endosomes drive their motility, dictate their morphology and affect cargo segregation. We have used well-characterized members of the SNX family to elucidate motor coupling using high-resolution light microscopy coupled with depletion of specific microtubule motors. Endosomal domains labelled with SNX1, SNX4 and SNX8 couple to discrete combinations of dynein and kinesin motors. These specific combinations govern the structure and motility of each SNX-coated membrane in addition to the segregation of distinct functional endosomal subdomains. Taken together, our data show that these key features of endosome dynamics are governed by the same set of opposing microtubule motors. Thus, microtubule motors help to define the mosaic layout of endosomes that underpins cargo sorting.
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Affiliation(s)
- Sylvie D Hunt
- Cell Biology Laboratories, School of Biochemistry, Medical Sciences Building, University of Bristol, University Walk, Bristol BS8 1TD, UK
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41
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Affiliation(s)
- Dave C. Anderson
- Center for Advanced Drug Research; SRI International; 140 Research Drive; Harrisonburg; Virginia; 22802; USA
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42
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Molecular basis for SNX-BAR-mediated assembly of distinct endosomal sorting tubules. EMBO J 2012; 31:4466-80. [PMID: 23085988 PMCID: PMC3512392 DOI: 10.1038/emboj.2012.283] [Citation(s) in RCA: 145] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2012] [Accepted: 09/25/2012] [Indexed: 12/23/2022] Open
Abstract
A systematic analysis of the dimerization, membrane remodelling and higher order assembly properties of all 12 human SNX-BAR sorting nexins reveals how different SNX-BAR combinations allow the formation of distinct tubular subdomains from the same endosomal vacuole during cargo sorting. Sorting nexins (SNXs) are regulators of endosomal sorting. For the SNX-BAR subgroup, a Bin/Amphiphysin/Rvs (BAR) domain is vital for formation/stabilization of tubular subdomains that mediate cargo recycling. Here, by analysing the in vitro membrane remodelling properties of all 12 human SNX-BARs, we report that some, but not all, can elicit the formation of tubules with diameters that resemble sorting tubules observed in cells. We reveal that SNX-BARs display a restricted pattern of BAR domain-mediated dimerization, and by resolving a 2.8 Å structure of a SNX1-BAR domain homodimer, establish that dimerization is achieved in part through neutralization of charged residues in the hydrophobic BAR-dimerization interface. Membrane remodelling also requires functional amphipathic helices, predicted to be present in all SNX-BARs, and the formation of high order SNX-BAR oligomers through selective ‘tip–loop' interactions. Overall, the restricted and selective nature of these interactions provide a molecular explanation for how distinct SNX-BAR-decorated tubules are nucleated from the same endosomal vacuole, as observed in living cells. Our data provide insight into the molecular mechanism that generates and organizes the tubular endosomal network.
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McGough IJ, Cullen PJ. Clathrin is not required for SNX-BAR-retromer-mediated carrier formation. J Cell Sci 2012; 126:45-52. [PMID: 23015596 DOI: 10.1242/jcs.112904] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Clathrin has been implicated in retromer-mediated trafficking, but its precise function remains elusive. Given the importance of retromers for efficient endosomal sorting, we have sought to clarify the relationship between clathrin and the SNX-BAR retromer. We find that the retromer SNX-BARs do not interact directly or indirectly with clathrin. In addition, we observe that SNX-BAR-retromer tubules and carriers are not clathrin coated. Furthermore, perturbing clathrin function, by overexpressing a dominant-negative clathrin or through suppression of clathrin expression, has no detectable effect on the frequency of SNX-BAR-retromer tubulation. We propose that SNX-BAR-retromer-mediated membrane deformation and carrier formation does not require clathrin, and hence the role of clathrin in SNX-BAR-retromer function would appear to lie in pre-SNX-BAR-retromer cargo sorting.
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Affiliation(s)
- Ian J McGough
- Henry Wellcome Integrated Signalling Laboratories, School of Biochemistry, Medical Sciences Building, University Walk, University of Bristol, Bristol BS8 1TD, UK
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44
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Bergan J, Dyve Lingelem AB, Simm R, Skotland T, Sandvig K. Shiga toxins. Toxicon 2012; 60:1085-107. [PMID: 22960449 DOI: 10.1016/j.toxicon.2012.07.016] [Citation(s) in RCA: 148] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2012] [Revised: 06/19/2012] [Accepted: 07/25/2012] [Indexed: 02/03/2023]
Abstract
Shiga toxins are virulence factors produced by the bacteria Shigella dysenteriae and certain strains of Escherichia coli. There is currently no available treatment for disease caused by these toxin-producing bacteria, and understanding the biology of the Shiga toxins might be instrumental in addressing this issue. In target cells, the toxins efficiently inhibit protein synthesis by inactivating ribosomes, and they may induce signaling leading to apoptosis. To reach their cytoplasmic target, Shiga toxins are endocytosed and transported by a retrograde pathway to the endoplasmic reticulum, before the enzymatically active moiety is translocated to the cytosol. The toxins thereby serve as powerful tools to investigate mechanisms of intracellular transport. Although Shiga toxins are a serious threat to human health, the toxins may be exploited for medical purposes such as cancer therapy or imaging.
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Affiliation(s)
- Jonas Bergan
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Norway
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45
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Annexin A1 and A2: roles in retrograde trafficking of Shiga toxin. PLoS One 2012; 7:e40429. [PMID: 22792315 PMCID: PMC3391278 DOI: 10.1371/journal.pone.0040429] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2012] [Accepted: 06/06/2012] [Indexed: 01/05/2023] Open
Abstract
Annexins constitute a family of calcium and membrane binding proteins. As annexin A1 and A2 have previously been linked to various membrane trafficking events, we initiated this study to investigate the role of these annexins in the uptake and intracellular transport of the bacterial Shiga toxin (Stx) and the plant toxin ricin. Once endocytosed, both toxins are retrogradely transported from endosomes to the Golgi apparatus and the endoplasmic reticulum before being targeted to the cytosol where they inhibit protein synthesis. This study was performed to obtain new information both about toxin transport and the function of annexin A1 and annexin A2. Our data show that depletion of annexin A1 or A2 alters the retrograde transport of Stx but not ricin, without affecting toxin binding or internalization. Knockdown of annexin A1 increases Golgi transport of Stx, whereas knockdown of annexin A2 slightly decreases the same transport step. Interestingly, annexin A1 was found in proximity to cytoplasmic phospholipase A2 (cPLA2), and the basal as well as the increased Golgi transport of Stx upon annexin A1 knockdown is dependent on cPLA2 activity. In conclusion, annexin A1 and A2 have different roles in Stx transport to the trans-Golgi network. The most prominent role is played by annexin A1 which normally works as a negative regulator of retrograde transport from the endosomes to the Golgi network, most likely by complex formation and inhibition of cPLA2.
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46
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McKenzie JE, Raisley B, Zhou X, Naslavsky N, Taguchi T, Caplan S, Sheff D. Retromer guides STxB and CD8-M6PR from early to recycling endosomes, EHD1 guides STxB from recycling endosome to Golgi. Traffic 2012; 13:1140-59. [PMID: 22540229 DOI: 10.1111/j.1600-0854.2012.01374.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Revised: 04/25/2012] [Accepted: 04/27/2012] [Indexed: 12/23/2022]
Abstract
Retrograde trafficking transports proteins, lipids and toxins from the plasma membrane to the Golgi and endoplasmic reticulum (ER). To reach the Golgi, these cargos must transit the endosomal system, consisting of early endosomes (EE), recycling endosomes, late endosomes and lysosomes. All cargos pass through EE, but may take different routes to the Golgi. Retromer-dependent cargos bypass the late endosomes to reach the Golgi. We compared how two very different retromer-dependent cargos negotiate the endosomal sorting system. Shiga toxin B, bound to the external layer of the plasma membrane, and chimeric CD8-mannose-6-phosphate receptor (CI-M6PR), which is anchored via a transmembrane domain. Both appear to pass through the recycling endosome. Ablation of the recycling endosome diverted both of these cargos to an aberrant compartment and prevented them from reaching the Golgi. Once in the recycling endosome, Shiga toxin required EHD1 to traffic to the TGN, while the CI-M6PR was not significantly dependent on EHD1. Knockdown of retromer components left cargo in the EE, suggesting that it is required for retrograde exit from this compartment. This work establishes the recycling endosome as a required step in retrograde traffic of at least these two retromer-dependent cargos. Along this pathway, retromer is associated with EE to recycling endosome traffic, while EHD1 is associated with recycling endosome to TGN traffic of STxB.
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Affiliation(s)
- Jenna E McKenzie
- Howard Hughes Medical Research Institute, Department of Molecular and Cellular Biology, University of California, Berkley, Berkley, CA 94720, USA
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47
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Abstract
The endo-lysosomal system is an interconnected tubulo-vesicular network that acts as a sorting station to process and distribute internalised cargo. This network accepts cargoes from both the plasma membrane and the biosynthetic pathway, and directs these cargos either towards the lysosome for degradation, the peri-nuclear recycling endosome for return to the cell surface, or to the trans-Golgi network. These intracellular membranes are variously enriched in different phosphoinositides that help to shape compartmental identity. These lipids act to localise a number of phosphoinositide-binding proteins that function as sorting machineries to regulate endosomal cargo sorting. Herein we discuss regulation of these machineries by phosphoinositides and explore how phosphoinositide-switching contributes toward sorting decisions made at this platform.
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Affiliation(s)
- Peter J Cullen
- Henry Wellcome Integrated Signaling Laboratories, School of Biochemistry, Medical Sciences Building, University of Bristol, BS8 1TD, Bristol, United Kingdom,
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48
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Cullen PJ, Korswagen HC. Sorting nexins provide diversity for retromer-dependent trafficking events. Nat Cell Biol 2011; 14:29-37. [PMID: 22193161 PMCID: PMC3613977 DOI: 10.1038/ncb2374] [Citation(s) in RCA: 265] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Sorting nexins are a large family of evolutionarily conserved phosphoinositide-binding proteins that have fundamental roles in orchestrating cargo sorting through the membranous maze that is the endosomal network. One ancient group of complexes that contain sorting nexins is the retromer. Here we discuss how retromer complexes regulate endosomal sorting, and describe how this is generating exciting new insight into the central role played by endosomal sorting in development and homeostasis of normal tissues.
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Affiliation(s)
- Peter J. Cullen
- Henry Wellcome Integrated Signalling Laboratories, School of Biochemistry, Medical Sciences Building, University Walk, University of Bristol, Bristol BS8 1TD, U.K
| | - Hendrik C. Korswagen
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences and University Medical Center Utrecht, Uppsalalaan 8, 3584 CT, Utrecht, The Netherlands
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49
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Dyve Lingelem AB, Bergan J, Sandvig K. Inhibitors of intravesicular acidification protect against Shiga toxin in a pH-independent manner. Traffic 2011; 13:443-54. [PMID: 22132807 DOI: 10.1111/j.1600-0854.2011.01319.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2011] [Revised: 11/28/2011] [Accepted: 12/01/2011] [Indexed: 01/01/2023]
Abstract
Shiga toxin inhibits protein synthesis after being transported from the cell surface to endosomes and retrogradely through the Golgi apparatus to the endoplasmic reticulum (ER) and into the cytosol. In this study, we have abolished proton gradients across internal membranes in different ways and investigated the effect on the various transport steps of Shiga toxin. Although inhibitors of the proton pump such as bafilomycin A1 and concanamycin A as well as some ionophores and chloroquine all protect against Shiga toxin, they mediate protection by inhibiting different transport steps. For instance, chloroquine protects the cells, although the toxin is transported to the ER. Importantly, our data indicate that proton pump activity is required for efficient endosome-to-Golgi transport of Shiga toxin, although acidification as such does not seem to be required.
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Affiliation(s)
- Anne Berit Dyve Lingelem
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Montebello, 0379 Oslo, Norway
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50
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Insights into the PX (phox-homology) domain and SNX (sorting nexin) protein families: structures, functions and roles in disease. Biochem J 2011; 441:39-59. [DOI: 10.1042/bj20111226] [Citation(s) in RCA: 212] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The mammalian genome encodes 49 proteins that possess a PX (phox-homology) domain, responsible for membrane attachment to organelles of the secretory and endocytic system via binding of phosphoinositide lipids. The PX domain proteins, most of which are classified as SNXs (sorting nexins), constitute an extremely diverse family of molecules that play varied roles in membrane trafficking, cell signalling, membrane remodelling and organelle motility. In the present review, we present an overview of the family, incorporating recent functional and structural insights, and propose an updated classification of the proteins into distinct subfamilies on the basis of these insights. Almost all PX domain proteins bind PtdIns3P and are recruited to early endosomal membranes. Although other specificities and localizations have been reported for a select few family members, the molecular basis for binding to other lipids is still not clear. The PX domain is also emerging as an important protein–protein interaction domain, binding endocytic and exocytic machinery, transmembrane proteins and many other molecules. A comprehensive survey of the molecular interactions governed by PX proteins highlights the functional diversity of the family as trafficking cargo adaptors and membrane-associated scaffolds regulating cell signalling. Finally, we examine the mounting evidence linking PX proteins to different disorders, in particular focusing on their emerging importance in both pathogen invasion and amyloid production in Alzheimer's disease.
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