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Zhou QX, Tian SY, Liu XN, Xiang SP, Lin XJ, Tan F, Mou YN. Research progress of ubiquitin and ubiquitin-like signaling in Toxoplasma gondii. Acta Trop 2024; 257:107283. [PMID: 38955322 DOI: 10.1016/j.actatropica.2024.107283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2024] [Revised: 06/03/2024] [Accepted: 06/07/2024] [Indexed: 07/04/2024]
Abstract
Toxoplasmosis, a zoonotic parasitic disease caused by Toxoplasma gondii (T. gondii), is prevalent worldwide. The fact should be emphasized that a considerable proportion of individuals infected with T. gondii may remain asymptomatic; nevertheless, the condition can have severe implications for pregnant women or immunocompromised individuals. The current treatment of toxoplasmosis primarily relies on medication; however, traditional anti-toxoplasmosis drugs exhibit significant limitations in terms of efficacy, side effects, and drug resistance. The life cycles of T. gondii are characterized by distinct stages and its body morphology goes through dynamic alterations during the growth cycle that are intricately governed by a wide array of post-translational modifications (PTMs). Ubiquitin (Ub) signaling and ubiquitin-like (Ubl) signaling are two crucial post-translational modification pathways within cells, regulating protein function, localization, stability, or interactions by attaching Ub or ubiquitin-like proteins (Ubls) to target proteins. While these signaling mechanisms share some functional similarities, they have distinct regulatory mechanisms and effects. T. gondii possesses both Ub and Ubls and plays a significant role in regulating the parasite's life cycle and maintaining its morphology through PTMs of substrate proteins. Investigating the role and mechanism of protein ubiquitination in T. gondii will provide valuable insights for preventing and treating toxoplasmosis. This review explores the distinctive characteristics of Ub and Ubl signaling in T. gondii, with the aim of inspiring research ideas for the identification of safer and more effective drug targets against toxoplasmosis.
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Affiliation(s)
- Qi-Xin Zhou
- Department of Parasitology, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou 325035, Zhejiang, PR China
| | - Si-Yu Tian
- Department of Parasitology, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou 325035, Zhejiang, PR China
| | - Xiao-Na Liu
- Department of Parasitology, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou 325035, Zhejiang, PR China
| | - Shi-Peng Xiang
- Department of Parasitology, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou 325035, Zhejiang, PR China
| | - Xue-Jing Lin
- Department of Parasitology, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou 325035, Zhejiang, PR China
| | - Feng Tan
- Department of Parasitology, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou 325035, Zhejiang, PR China
| | - Ya-Ni Mou
- Department of Parasitology, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou 325035, Zhejiang, PR China.
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2
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Tang C, Qiao X, Jin Y, Yang W, Yu Z, Wang L, Song L. An LPS-induced TNF-α factor involved in immune response of oyster Crassostrea gigas by regulating haemocytes apoptosis. FISH & SHELLFISH IMMUNOLOGY 2024; 148:109513. [PMID: 38521141 DOI: 10.1016/j.fsi.2024.109513] [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: 01/12/2024] [Revised: 03/13/2024] [Accepted: 03/15/2024] [Indexed: 03/25/2024]
Abstract
LPS induced TNF-α Factor (LITAF) is a transcription factor widely involving in activation of Tumor Necrosis Factor (TNF) and other cytokines in the inflammatory response. In the present study, a homologue of LITAF with a conserved LITAF domain was identified from the Pacific oyster Crassostrea gigas. The transcripts of CgLITAF were detected in all examined tissues with highest expression in hepatopancrease. The immunofluorescence assay and Western blot showed that LPS stimulation induced an obvious nucleus translocation of CgLITAF protein in haemocytes. While the mRNA level of CgLITAF changed slightly after LPS stimulation. When the siRNA of CgLITAF was injected to inhibit its expression, the apoptotic level of haemocytes decreased observably after LPS stimulation. Consistently, the transcripts of CgTNF3 and CgTNF4 (LOC105343080, LOC105341146), the apoptotic-related molecules including CgBax, CgCytochrome c, CgCaspase9 and CgCaspase3, were significantly suppressed in the CgLITAF-RNAi oysters. While the mRNA expression level of CgBcl was enhanced significantly in the CgLITAF-RNAi oysters. These results indicated that CgLITAF promoted haemocyte apoptosis by regulating the expression of apoptotic-related factors, suggesting its important role in the immune response of oysters.
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Affiliation(s)
- Chunyu Tang
- Liaoning Key Laboratory of Marine Animal Immunology and Disease Control, Dalian Ocean University, Dalian, 116023, China; Laboratory of Marine Fisheries Science and Food Production Process, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266235, China
| | - Xue Qiao
- Liaoning Key Laboratory of Marine Animal Immunology and Disease Control, Dalian Ocean University, Dalian, 116023, China; Southern Laboratory of Ocean Science and Engineering (Guangdong, Zhuhai), Zhuhai, 519000, China; Laboratory of Marine Fisheries Science and Food Production Process, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266235, China.
| | - Yuhao Jin
- Liaoning Key Laboratory of Marine Animal Immunology and Disease Control, Dalian Ocean University, Dalian, 116023, China; Laboratory of Marine Fisheries Science and Food Production Process, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266235, China
| | - Wenwen Yang
- Liaoning Key Laboratory of Marine Animal Immunology and Disease Control, Dalian Ocean University, Dalian, 116023, China; Laboratory of Marine Fisheries Science and Food Production Process, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266235, China
| | - Zhuo Yu
- Liaoning Key Laboratory of Marine Animal Immunology and Disease Control, Dalian Ocean University, Dalian, 116023, China; Laboratory of Marine Fisheries Science and Food Production Process, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266235, China
| | - Lingling Wang
- Liaoning Key Laboratory of Marine Animal Immunology and Disease Control, Dalian Ocean University, Dalian, 116023, China; Southern Laboratory of Ocean Science and Engineering (Guangdong, Zhuhai), Zhuhai, 519000, China; Laboratory of Marine Fisheries Science and Food Production Process, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266235, China; Dalian Key Laboratory of Aquatic Animal Disease Prevention and Control, Dalian Ocean University, Dalian, 116023, China.
| | - Linsheng Song
- Liaoning Key Laboratory of Marine Animal Immunology and Disease Control, Dalian Ocean University, Dalian, 116023, China; Southern Laboratory of Ocean Science and Engineering (Guangdong, Zhuhai), Zhuhai, 519000, China; Laboratory of Marine Fisheries Science and Food Production Process, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266235, China; Dalian Key Laboratory of Aquatic Animal Disease Prevention and Control, Dalian Ocean University, Dalian, 116023, China
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3
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Stefani C, Bruchez AM, Rosasco MG, Yoshida AE, Fasano KJ, Levan PF, Lorant A, Hubbard NW, Oberst A, Stuart LM, Lacy-Hulbert A. LITAF protects against pore-forming protein-induced cell death by promoting membrane repair. Sci Immunol 2024; 9:eabq6541. [PMID: 38181093 DOI: 10.1126/sciimmunol.abq6541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Accepted: 11/09/2023] [Indexed: 01/07/2024]
Abstract
Pore-forming toxins (PFTs) are the largest class of bacterial toxins and contribute to virulence by triggering host cell death. Vertebrates also express endogenous pore-forming proteins that induce cell death as part of host defense. To mitigate damage and promote survival, cells mobilize membrane repair mechanisms to neutralize and counteract pores, but how these pathways are activated is poorly understood. Here, we use a transposon-based gene activation screen to discover pathways that counteract the cytotoxicity of the archetypal PFT Staphylococcus aureus α-toxin. We identify the endolysosomal protein LITAF as a mediator of cellular resistance to PFT-induced cell death that is active against both bacterial toxins and the endogenous pore, gasdermin D, a terminal effector of pyroptosis. Activation of the ubiquitin ligase NEDD4 by potassium efflux mobilizes LITAF to recruit the endosomal sorting complexes required for transport (ESCRT) machinery to repair damaged membrane. Cells lacking LITAF, or carrying naturally occurring disease-associated mutations of LITAF, are highly susceptible to pore-induced death. Notably, LITAF-mediated repair occurs at endosomal membranes, resulting in expulsion of damaged membranes as exosomes, rather than through direct excision of pores from the surface plasma membrane. These results identify LITAF as a key effector that links sensing of cellular damage to repair.
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Affiliation(s)
- Caroline Stefani
- Center for Systems Immunology, Benaroya Research Institute at Virginia Mason, Seattle, WA, USA
| | - Anna M Bruchez
- Center for Systems Immunology, Benaroya Research Institute at Virginia Mason, Seattle, WA, USA
| | - Mario G Rosasco
- Center for Systems Immunology, Benaroya Research Institute at Virginia Mason, Seattle, WA, USA
| | - Anna E Yoshida
- Center for Systems Immunology, Benaroya Research Institute at Virginia Mason, Seattle, WA, USA
| | - Kayla J Fasano
- Center for Systems Immunology, Benaroya Research Institute at Virginia Mason, Seattle, WA, USA
- Department of Immunology, University of Washington, Seattle, WA, USA
| | - Paula F Levan
- Center for Systems Immunology, Benaroya Research Institute at Virginia Mason, Seattle, WA, USA
| | - Alina Lorant
- Center for Systems Immunology, Benaroya Research Institute at Virginia Mason, Seattle, WA, USA
- Department of Immunology, University of Washington, Seattle, WA, USA
| | | | - Andrew Oberst
- Department of Immunology, University of Washington, Seattle, WA, USA
| | - Lynda M Stuart
- Center for Systems Immunology, Benaroya Research Institute at Virginia Mason, Seattle, WA, USA
- Institute for Protein Design, Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Adam Lacy-Hulbert
- Center for Systems Immunology, Benaroya Research Institute at Virginia Mason, Seattle, WA, USA
- Department of Immunology, University of Washington, Seattle, WA, USA
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4
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Libberecht K, Vangansewinkel T, Van Den Bosch L, Lambrichts I, Wolfs E. Proteostasis plays an important role in demyelinating Charcot Marie Tooth disease. Biochem Pharmacol 2023; 216:115760. [PMID: 37604292 DOI: 10.1016/j.bcp.2023.115760] [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: 06/01/2023] [Revised: 08/17/2023] [Accepted: 08/18/2023] [Indexed: 08/23/2023]
Abstract
Type 1 Charcot-Marie-Tooth disease (CMT1) is the most common demyelinating peripheral neuropathy. Patients suffer from progressive muscle weakness and sensory problems. The underlying disease mechanisms of CMT1 are still unclear and no therapy is currently available, hence patients completely rely on supportive care. Balancing protein levels is a complex multistep process fundamental to maintain cells in their healthy state and a disrupted proteostasis is a hallmark of several neurodegenerative diseases. When protein misfolding occurs, protein quality control systems are activated such as chaperones, the lysosomal-autophagy system and proteasomal degradation to ensure proper degradation. However, in pathological circumstances, these mechanisms are overloaded and thereby become inefficient to clear the load of misfolded proteins. Recent evidence strongly indicates that a disbalance in proteostasis plays an important role in several forms of CMT1. In this review, we present an overview of the protein quality control systems, their role in CMT1, and potential treatment strategies to restore proteostasis.
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Affiliation(s)
- Karen Libberecht
- UHasselt, Biomedical Research Institute (BIOMED), Lab for Functional Imaging & Research on Stem Cells (FIERCELab), Diepenbeek, Belgium; VIB, Center for Brain & Disease Research, Laboratory of Neurobiology, Leuven, Belgium.
| | - Tim Vangansewinkel
- UHasselt, Biomedical Research Institute (BIOMED), Lab for Functional Imaging & Research on Stem Cells (FIERCELab), Diepenbeek, Belgium; VIB, Center for Brain & Disease Research, Laboratory of Neurobiology, Leuven, Belgium; UHasselt, Biomedical Research Institute (BIOMED), Lab for Histology and Regeneration (HISTOREGEN Lab), Diepenbeek, Belgium
| | - Ludo Van Den Bosch
- KU Leuven, Department of Neurosciences, Experimental Neurology, and Leuven Brain Institute (LBI), Leuven, Belgium; VIB, Center for Brain & Disease Research, Laboratory of Neurobiology, Leuven, Belgium
| | - Ivo Lambrichts
- UHasselt, Biomedical Research Institute (BIOMED), Lab for Histology and Regeneration (HISTOREGEN Lab), Diepenbeek, Belgium
| | - Esther Wolfs
- UHasselt, Biomedical Research Institute (BIOMED), Lab for Functional Imaging & Research on Stem Cells (FIERCELab), Diepenbeek, Belgium.
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5
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Cheng Z, Stefani C, Skillman T, Klimas A, Lee A, DiBernardo EF, Brown KM, Milman T, Wang Y, Gallagher BR, Lagree K, Jena BP, Pulido JS, Filler SG, Mitchell AP, Hiller NL, Lacy‐Hulbert A, Zhao Y. MicroMagnify: A Multiplexed Expansion Microscopy Method for Pathogens and Infected Tissues. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2302249. [PMID: 37658522 PMCID: PMC10602566 DOI: 10.1002/advs.202302249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Revised: 07/29/2023] [Indexed: 09/03/2023]
Abstract
Super-resolution optical imaging tools are crucial in microbiology to understand the complex structures and behavior of microorganisms such as bacteria, fungi, and viruses. However, the capabilities of these tools, particularly when it comes to imaging pathogens and infected tissues, remain limited. MicroMagnify (µMagnify) is developed, a nanoscale multiplexed imaging method for pathogens and infected tissues that are derived from an expansion microscopy technique with a universal biomolecular anchor. The combination of heat denaturation and enzyme cocktails essential is found for robust cell wall digestion and expansion of microbial cells and infected tissues without distortion. µMagnify efficiently retains biomolecules suitable for high-plex fluorescence imaging with nanoscale precision. It demonstrates up to eightfold expansion with µMagnify on a broad range of pathogen-containing specimens, including bacterial and fungal biofilms, infected culture cells, fungus-infected mouse tone, and formalin-fixed paraffin-embedded human cornea infected by various pathogens. Additionally, an associated virtual reality tool is developed to facilitate the visualization and navigation of complex 3D images generated by this method in an immersive environment allowing collaborative exploration among researchers worldwide. µMagnify is a valuable imaging platform for studying how microbes interact with their host systems and enables the development of new diagnosis strategies against infectious diseases.
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Affiliation(s)
- Zhangyu Cheng
- Department of Biological SciencesCarnegie Mellon University4400 Fifth AvenuePittsburghPA15213USA
| | - Caroline Stefani
- Benaroya Research Institute at Virginia Mason1201 9th AveSeattleWA98101USA
| | | | - Aleksandra Klimas
- Department of Biological SciencesCarnegie Mellon University4400 Fifth AvenuePittsburghPA15213USA
| | - Aramchan Lee
- Department of Biological SciencesCarnegie Mellon University4400 Fifth AvenuePittsburghPA15213USA
| | - Emma F. DiBernardo
- Department of Biological SciencesCarnegie Mellon University4400 Fifth AvenuePittsburghPA15213USA
| | - Karina Mueller Brown
- Department of Biological SciencesCarnegie Mellon University4400 Fifth AvenuePittsburghPA15213USA
| | - Tatyana Milman
- Wills Eye Hospital and Jefferson University HospitalPhiladelphiaPA19107USA
| | - Yuhong Wang
- Department of Biological SciencesCarnegie Mellon University4400 Fifth AvenuePittsburghPA15213USA
| | - Brendan R. Gallagher
- Department of Biological SciencesCarnegie Mellon University4400 Fifth AvenuePittsburghPA15213USA
| | - Katherine Lagree
- Department of Biological SciencesCarnegie Mellon University4400 Fifth AvenuePittsburghPA15213USA
| | - Bhanu P. Jena
- Viron Molecular Medicine Institute201 Washington StreetBostonMA02201USA
- Department of PhysiologyWayne State University42 W Warren AveDetroitMI48202USA
- NanoBioScience InstituteWayne State University42 W Warren AveDetroitMI48202USA
- Center for Molecular Medicine & GeneticsSchool of MedicineWayne State University42 W Warren AveDetroitMI48202USA
| | - Jose S. Pulido
- Wills Eye Hospital and Jefferson University HospitalPhiladelphiaPA19107USA
| | - Scott G. Filler
- Lundquist Institute for Biomedical Innovation at Harbor‐UCLA Medical Center1124 W Carson StTorranceCA90502USA
- David Geffen School of Medicine at UCLA10833 Le Conte AveLos AngelesCA90095USA
| | - Aaron P. Mitchell
- Department of Biological SciencesCarnegie Mellon University4400 Fifth AvenuePittsburghPA15213USA
- Department of MicrobiologyUniversity of Georgia210 S Jackson streetAthensGA30602USA
| | - N. Luisa Hiller
- Department of Biological SciencesCarnegie Mellon University4400 Fifth AvenuePittsburghPA15213USA
| | - Adam Lacy‐Hulbert
- Benaroya Research Institute at Virginia Mason1201 9th AveSeattleWA98101USA
| | - Yongxin Zhao
- Department of Biological SciencesCarnegie Mellon University4400 Fifth AvenuePittsburghPA15213USA
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6
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Zhao Y, Cheng Z, Stefani C, Skillman T, Klimas A, Lee A, DiBernardo E, Mueller Brown K, Milman T, Gallagher B, Lagree K, Jena B, Pulido J, Filler S, Mitchell A, Hiller L, Lacy-Hulbert A. MicroMagnify: a multiplexed expansion microscopy method for pathogens and infected tissues. RESEARCH SQUARE 2023:rs.3.rs-2637060. [PMID: 36945526 PMCID: PMC10029075 DOI: 10.21203/rs.3.rs-2637060/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/08/2023]
Abstract
Super-resolution optical imaging tools are crucial in microbiology to understand the complex structures and behavior of microorganisms such as bacteria, fungi, and viruses. However, the capabilities of these tools, particularly when it comes to imaging pathogens and infected tissues, remain limited. We developed µMagnify, a nanoscale multiplexed imaging method for pathogens and infected tissues that are derived from an expansion microscopy technique with a universal biomolecular anchor. We formulated an enzyme cocktail specifically designed for robust cell wall digestion and expansion of microbial cells without distortion while efficiently retaining biomolecules suitable for high-plex fluorescence imaging with nanoscale precision. Additionally, we developed an associated virtual reality tool to facilitate the visualization and navigation of complex three-dimensional images generated by this method in an immersive environment allowing collaborative exploration among researchers around the world. µMagnify is a valuable imaging platform for studying how microbes interact with their host systems and enables development of new diagnosis strategies against infectious diseases.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | - Bhanu Jena
- Wayne State University School of Medicine
| | - Jose Pulido
- Wills Eye Hospital and Jefferson University Hospital
| | - Scott Filler
- Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center
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Kavain ablates the radio-resistance of IDH-wildtype glioblastoma by targeting LITAF/NF-κB pathway. Cell Oncol (Dordr) 2023; 46:179-193. [PMID: 36464713 DOI: 10.1007/s13402-022-00743-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/27/2022] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Glioblastoma multiforma (GBM) is the most malignant intrinsic tumor of the central nervous system (CNS), with high morbidity of 3.19/100,000 per year and a poor 5-year survival rate (< 5%) worldwide. Numerous studies have indicated that GBM shows remarkable radioresistance and aggressive recurrence. However, the mechanisms to endow GBM cells with radioresistance are complex and unclear. METHODS Cell growth curve and colony formation assays were used to analyze the radioresistance of GBM. Immunoprecipitation and immunoblotting experiments were carried out to analyze protein expression and interaction. RESULTS In the present study, we found that LITAF, lipopolysaccharide (LPS)-induced tumor necrosis factor (TNF)-α factor, is up-regulated both in mRNA and protein in GBM tumors. Meanwhile, we observed that high LITAF expression contributes to radioresistance of GBM cell lines (including U87, U251, DK, and AM38 cells), indicated by knockout or knockdown of LITAF in cells sensitizing them to radiation treatment both in vitro and in vivo. Furthermore, we demonstrated that kavain, an active constituent of Piper methysticum Forst., effectively ablates GSC-like cells' (such as CD133 + U87, U251, DK, and AM38 populations) radioresistance in a LITAF-dependent manner. CONCLUSION In mechanism, our results indicated that 1) the elevation of LITAF in GBM cells activates the NF-κB pathway to promote mesenchymal transition, and 2) kavain disturbs STAT6B/LITAF protein interaction and then expels LITAF from the nucleus. Therefore, we consider that kavain may be a potential candidate to develop an irradiation therapy adjuvant for GBM.
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Hsp70–Bag3 Module Regulates Macrophage Motility and Tumor Infiltration via Transcription Factor LITAF and CSF1. Cancers (Basel) 2022; 14:cancers14174168. [PMID: 36077705 PMCID: PMC9454964 DOI: 10.3390/cancers14174168] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 08/22/2022] [Accepted: 08/23/2022] [Indexed: 11/25/2022] Open
Abstract
Simple Summary Patients’ normal cells, such as lymphocytes, fibroblasts, or macrophages, can either suppress or facilitate tumor growth. Macrophages can infiltrate tumors and secrete molecules that enhance the proliferation of cancer cells and their invasion into neighboring tissues and blood. Here, we investigated the mechanism of action of a novel small molecule that suppresses the infiltration of macrophages into tumors and demonstrates potent anticancer activity. We identified the entire pathway that links the intracellular protein Hsp70, which is inhibited by this small molecule, with the macrophage motility system. This study will lay the basis for a novel approach to cancer treatment via targeting tumor-associated macrophages. Abstract The molecular chaperone Hsp70 has been implicated in multiple stages of cancer development. In these processes, a co-chaperone Bag3 links Hsp70 with signaling pathways that control cancer development. Recently, we showed that besides affecting cancer cells, Hsp70 can also regulate the motility of macrophages and their tumor infiltration. However, the mechanisms of these effects have not been explored. Here, we demonstrated that the Hsp70-bound co-chaperone Bag3 associates with a transcription factor LITAF that can regulate the expression of inflammatory cytokines and chemokines in macrophages. Via this interaction, the Hsp70–Bag3 complex regulates expression levels of LITAF by controlling its proteasome-dependent and chaperone-mediated autophagy-dependent degradation. In turn, LITAF regulates the expression of the major chemokine CSF1, and adding this chemokine to the culture medium reversed the effects of Bag3 or LITAF silencing on the macrophage motility. Together, these findings uncover the Hsp70–Bag3–LITAF–CSF1 pathway that controls macrophage motility and tumor infiltration.
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Ubap1 knock-in mice reproduced the phenotype of SPG80. J Hum Genet 2022; 67:679-686. [PMID: 35962060 DOI: 10.1038/s10038-022-01073-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 07/03/2022] [Accepted: 07/28/2022] [Indexed: 11/08/2022]
Abstract
SPG80 is a neurodegenerative disorder characterized by a pure type of juvenile-onset hereditary spastic paraplegia and is caused by a heterozygous mutation of the UBAP1 (ubiquitin-associated protein 1) gene. UBAP1 is one of the subunits of the endosomal sorting complex required for transport I and plays a role in endosome sorting by binding to ubiquitin-tagged proteins. In this study, we generated novel Ubap1+/E176Efx23 knock-in mice, in which the SOUBA domain of Ubap1 was completely deleted with the UMA domain being intact, as an animal model of SPG80. The knock-in mice with this heterozygous Ubap1 truncated mutation appeared normal at birth, but they developed progressive hind limb dysfunction several months later. Molecular pathologically, loss of neurons in the spinal cord and accumulation of ubiquitinated proteins were observed in Ubap1+/E176Efx23 knock-in mice. In addition, changes in the distributions of Rab5 and Rab7 in the spinal cord suggest that this mutation in Ubap1 disturbs endosome-mediated vesicular trafficking. This is the first report of a mouse model that reproduces the phenotype of SPG80. Our knock-in mice may provide a clue for understanding the molecular pathogenesis underlying UBAP1-related HSP and screening of therapeutic agents.
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Song J, Liu Y, Wan J, Zhao GN, Wang JC, Dai Z, Hu S, Yang L, Liu Z, Fu Y, Dong E, Tang YD. SIMPLE Is an Endosomal Regulator That Protects Against NAFLD by Targeting the Lysosomal Degradation of EGFR. Hepatology 2021; 74:3091-3109. [PMID: 34320238 DOI: 10.1002/hep.32075] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 06/25/2021] [Accepted: 06/28/2021] [Indexed: 12/12/2022]
Abstract
BACKGROUND AND AIMS NAFLD has become a tremendous burden for public health; however, there is no drug for NAFLD therapy at present. Impaired endo-lysosome-mediated protein degradation is observed in a variety of metabolic disorders, such as atherosclerosis, type 2 diabetes mellitus, and NAFLD. Small integral membrane protein of lysosome/late endosome (SIMPLE) is a regulator of endosome-to-lysosome trafficking and cell signaling, but the role that SIMPLE plays in NAFLD progression remains unknown. Here we investigated SIMPLE function in NAFLD development and sophisticated mechanism therein. APPROACH AND RESULTS This study found that in vitro knockdown of SIMPLE significantly aggravated lipid accumulation and inflammation in hepatocytes treated with metabolic stimulation. Consistently, in vivo experiments showed that liver-specific Simple-knockout (Simple-HKO) mice exhibited more severe high-fat diet (HFD)-induced, high-fat-high-cholesterol diet (HFHC)-induced, and methionine-choline-deficient diet (MCD)-induced steatosis, glucose intolerance, inflammation, and fibrosis than those fed with normal chow (NC) diet. Meanwhile, RNA-sequencing demonstrated the up-regulated signaling pathways and signature genes involved in lipid metabolism, inflammation, and fibrosis in Simple-HKO mice compared with control mice under metabolic stress. Mechanically, we found SIMPLE directly interact with epidermal growth factor receptor (EGFR). SIMPLE deficiency results in dysregulated degradation of EGFR, subsequently hyperactivated EGFR phosphorylation, thus exaggerating NAFLD development. Moreover, we demonstrated that using EGFR inhibitor or silencing EGFR expression could ameliorate lipid accumulation induced by the knockdown of SIMPLE. CONCLUSIONS SIMPLE ameliorated NASH by prompting EGFR degradation and can be a potential therapeutic candidate for NASH.
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Affiliation(s)
- Jingjing Song
- Department of Cardiology, State Key Laboratory of Cardiovascular Disease, National Center for Cardiovascular Diseases, Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.,Graduate School of Peking Union Medical College, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Yupeng Liu
- Department of Cardiology, State Key Laboratory of Cardiovascular Disease, National Center for Cardiovascular Diseases, Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.,Graduate School of Peking Union Medical College, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Juan Wan
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Guang-Nian Zhao
- Medical Science Research Center, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Jian-Cheng Wang
- Beijing Key Laboratory of Molecular Pharmaceutics and New Drug Delivery Systems, State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing, China
| | - Zhifei Dai
- Department of Biomedical Engineering, College of Future Technology, Peking University, Beijing, China
| | - Sha Hu
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Ling Yang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Zhen Liu
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Yi Fu
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University Health Science Center, Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, Beijing, China
| | - Erdan Dong
- The Institute of Cardiovascular Sciences, Peking University, NHC Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides, Beijing Key Laboratory of Cardiovascular Receptors Research, Beijing, China.,Department of Cardiology and Institute of Vascular Medicine, Peking University Third Hospital, Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, Beijing, China
| | - Yi-Da Tang
- Department of Cardiology, State Key Laboratory of Cardiovascular Disease, National Center for Cardiovascular Diseases, Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.,Graduate School of Peking Union Medical College, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.,Department of Cardiology and Institute of Vascular Medicine, Peking University Third Hospital, Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, Beijing, China
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11
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Wunderley L, Zhang L, Yarwood R, Qin W, Lowe M, Woodman P. Endosomal recycling tubule scission and integrin recycling involve the membrane curvature-supporting protein LITAF. J Cell Sci 2021; 134:jcs258549. [PMID: 34342350 PMCID: PMC8353527 DOI: 10.1242/jcs.258549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 06/16/2021] [Indexed: 11/20/2022] Open
Abstract
Recycling to the cell surface requires the scission of tubular membrane intermediates emanating from endosomes. Here, we identify the monotopic membrane protein LPS-induced TNF-activating factor (LITAF) and the related protein cell death involved p53 target 1 (CDIP1) as novel membrane curvature proteins that contribute to recycling tubule scission. Recombinant LITAF supports high membrane curvature, shown by its ability to reduce proteoliposome size. The membrane domains of LITAF and CDIP1 partition strongly into ∼50 nm diameter tubules labelled with the recycling markers Pacsin2, ARF6 and SNX1, and the recycling cargoes MHC class I and CD59. Partitioning of LITAF into tubules is impaired by mutations linked to Charcot Marie Tooth disease type 1C. Meanwhile, co-depletion of LITAF and CDIP1 results in the expansion of tubular recycling compartments and stabilised Rab11 tubules, pointing to a function for LITAF and CDIP1 in membrane scission. Consistent with this, co-depletion of LITAF and CDIP1 impairs integrin recycling and cell migration.
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Affiliation(s)
| | | | | | | | | | - Philip Woodman
- Faculty of Biology Medicine and Health, Manchester Academic and Health Science Centre, University of Manchester, Manchester M13 9PT, UK
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12
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Chen K, Tian J, Wang J, Jia Z, Zhang Q, Huang W, Zhao X, Gao Z, Gao Q, Zou J. Lipopolysaccharide-induced TNFα factor (LITAF) promotes inflammatory responses and activates apoptosis in zebrafish Danio rerio. Gene 2021; 780:145487. [PMID: 33588039 DOI: 10.1016/j.gene.2021.145487] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 01/10/2021] [Accepted: 02/01/2021] [Indexed: 01/05/2023]
Abstract
Lipopolysaccharide-induced TNFα factor (LITAF) is an important transcription factor which activates the transcription of TNFα and regulates cell apoptosis and inflammatory response. In the present study, a LITAF gene homologue was identified in zebrafish (Danio rerio) and was shown to be well conserved in the protein sequence, genomic organization and synteny with human LITAF. DrLITAF was constitutively expressed in tissues, with the highest expression detected in the gills. Its expression could be modulated by LPS, poly(I:C), and infection with Edwardsiella tarda, Aeromonus hydrophila and septicemia viremia of carp virus (SVCV). DrLITAF, when overexpressed, was shown to be located on the cellular membrane and nuclear membrane of HEK293T and ZF4 cells and was associated with the endoplasmic reticulum. Stimulation with LPS resulted in rapid translocation of DrLITAF into the nucleus. In addition, DrLITAF was able to induce cell apoptosis and the expression of caspase 3. The results demonstrate that DrLITAF is involved in the immune defence against bacterial and viral infection and plays a role in regulating inflammation and apoptosis.
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Affiliation(s)
- Kangyong Chen
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai 201306, China; International Research Center for Marine Biosciences at Shanghai Ocean University, Ministry of Science and Technology, China
| | - Jiayin Tian
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai 201306, China; International Research Center for Marine Biosciences at Shanghai Ocean University, Ministry of Science and Technology, China
| | - Junya Wang
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai 201306, China; International Research Center for Marine Biosciences at Shanghai Ocean University, Ministry of Science and Technology, China
| | - Zhao Jia
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai 201306, China; International Research Center for Marine Biosciences at Shanghai Ocean University, Ministry of Science and Technology, China
| | - Qin Zhang
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai 201306, China; International Research Center for Marine Biosciences at Shanghai Ocean University, Ministry of Science and Technology, China
| | - Wenji Huang
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai 201306, China; International Research Center for Marine Biosciences at Shanghai Ocean University, Ministry of Science and Technology, China
| | - Xin Zhao
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai 201306, China; International Research Center for Marine Biosciences at Shanghai Ocean University, Ministry of Science and Technology, China
| | - Zhipeng Gao
- Hunan Engineering Technology Research Center of Featured Aquatic Resources Utilization, College of Animal Science and Technology, Hunan Agricultural University, Changsha 410128, China
| | - Qian Gao
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai 201306, China; International Research Center for Marine Biosciences at Shanghai Ocean University, Ministry of Science and Technology, China
| | - Jun Zou
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai 201306, China; International Research Center for Marine Biosciences at Shanghai Ocean University, Ministry of Science and Technology, China; Hunan Engineering Technology Research Center of Featured Aquatic Resources Utilization, College of Animal Science and Technology, Hunan Agricultural University, Changsha 410128, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.
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13
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Lavado-García J, Díaz-Maneh A, Canal-Paulí N, Pérez-Rubio P, Gòdia F, Cervera L. Metabolic engineering of HEK293 cells to improve transient transfection and cell budding of HIV-1 virus-like particles. Biotechnol Bioeng 2021; 118:1649-1663. [PMID: 33463716 DOI: 10.1002/bit.27679] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2020] [Accepted: 01/12/2021] [Indexed: 01/08/2023]
Abstract
HIV-1 Gag virus-like particles (VLPs) are promising candidates for the development of future vaccines. Recent viral outbreaks have manifested the need of robust vaccine production platforms able to adapt to new challenges while achieving mass production capacity. For the rapid production of VLPs, the method of transient gene expression (TGE) have proved highly efficient. Based on a previous characterization of the HEK293 cell line upon transient transfection using multiplexed quantitative proteomics, molecular production bottlenecks and metabolic pathways likely to be optimized were identified. In this study, these molecular components and metabolic pathways have been explored and modulated via transient metabolic engineering using approaches like design of experiments to fully exploit and optimize VLP production, transfection and budding efficiency. Upon overexpression of endosomal sorting complex required for transport accessory proteins like NEDD4L and CIT, VLP production increased 3.3 and 2.9-fold, respectively. Overexpression of glycosphingolipid precursor enzyme UGCG improved transfection efficiency by 17% and knocking-down the Gag-binding protein CNP improved 2.5-fold VLP specific productivity. Combining CNP inhibition and UGCG overexpression further improved budding efficiency by 37.3%. Modulating VLP production and accessory pathways like intracellular budding, demonstrated the potential of metabolic engineering to optimize and intensify the development of robust production platforms for future vaccines.
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Affiliation(s)
- Jesús Lavado-García
- Grup d'Enginyeria Cellular i Bioprocessos, Escola d'Enginyeria, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Andy Díaz-Maneh
- Grup d'Enginyeria Cellular i Bioprocessos, Escola d'Enginyeria, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Núria Canal-Paulí
- Grup d'Enginyeria Cellular i Bioprocessos, Escola d'Enginyeria, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Pol Pérez-Rubio
- Grup d'Enginyeria Cellular i Bioprocessos, Escola d'Enginyeria, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Francesc Gòdia
- Grup d'Enginyeria Cellular i Bioprocessos, Escola d'Enginyeria, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Laura Cervera
- Grup d'Enginyeria Cellular i Bioprocessos, Escola d'Enginyeria, Universitat Autònoma de Barcelona, Barcelona, Spain
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14
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Inukai R, Mori K, Kuwata K, Suzuki C, Maki M, Takahara T, Shibata H. The Novel ALG-2 Target Protein CDIP1 Promotes Cell Death by Interacting with ESCRT-I and VAPA/B. Int J Mol Sci 2021; 22:ijms22031175. [PMID: 33503978 PMCID: PMC7865452 DOI: 10.3390/ijms22031175] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2020] [Revised: 01/20/2021] [Accepted: 01/21/2021] [Indexed: 12/15/2022] Open
Abstract
Apoptosis-linked gene 2 (ALG-2, also known as PDCD6) is a member of the penta-EF-hand (PEF) family of Ca2+-binding proteins. The murine gene encoding ALG-2 was originally reported to be an essential gene for apoptosis. However, the role of ALG-2 in cell death pathways has remained elusive. In the present study, we found that cell death-inducing p53 target protein 1 (CDIP1), a pro-apoptotic protein, interacts with ALG-2 in a Ca2+-dependent manner. Co-immunoprecipitation analysis of GFP-fused CDIP1 (GFP-CDIP1) revealed that GFP-CDIP1 associates with tumor susceptibility gene 101 (TSG101), a known target of ALG-2 and a subunit of endosomal sorting complex required for transport-I (ESCRT-I). ESCRT-I is a heterotetrameric complex composed of TSG101, VPS28, VPS37 and MVB12/UBAP1. Of diverse ESCRT-I species originating from four VPS37 isoforms (A, B, C, and D), CDIP1 preferentially associates with ESCRT-I containing VPS37B or VPS37C in part through the adaptor function of ALG-2. Overexpression of GFP-CDIP1 in HEK293 cells caused caspase-3/7-mediated cell death. In addition, the cell death was enhanced by co-expression of ALG-2 and ESCRT-I, indicating that ALG-2 likely promotes CDIP1-induced cell death by promoting the association between CDIP1 and ESCRT-I. We also found that CDIP1 binds to vesicle-associated membrane protein-associated protein (VAP)A and VAPB through the two phenylalanines in an acidic tract (FFAT)-like motif in the C-terminal region of CDIP1, mutations of which resulted in reduction of CDIP1-induced cell death. Therefore, our findings suggest that different expression levels of ALG-2, ESCRT-I subunits, VAPA and VAPB may have an impact on sensitivity of anticancer drugs associated with CDIP1 expression.
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Affiliation(s)
- Ryuta Inukai
- Department of Applied Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan; (R.I.); (K.M.); (C.S.); (M.M.); (T.T.)
| | - Kanako Mori
- Department of Applied Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan; (R.I.); (K.M.); (C.S.); (M.M.); (T.T.)
| | - Keiko Kuwata
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan;
| | - Chihiro Suzuki
- Department of Applied Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan; (R.I.); (K.M.); (C.S.); (M.M.); (T.T.)
| | - Masatoshi Maki
- Department of Applied Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan; (R.I.); (K.M.); (C.S.); (M.M.); (T.T.)
| | - Terunao Takahara
- Department of Applied Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan; (R.I.); (K.M.); (C.S.); (M.M.); (T.T.)
| | - Hideki Shibata
- Department of Applied Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan; (R.I.); (K.M.); (C.S.); (M.M.); (T.T.)
- Correspondence:
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15
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Turan NN, Moshal KS, Roder K, Baggett BC, Kabakov AY, Dhakal S, Teramoto R, Chiang DYE, Zhong M, Xie A, Lu Y, Dudley SC, MacRae CA, Karma A, Koren G. The endosomal trafficking regulator LITAF controls the cardiac Nav1.5 channel via the ubiquitin ligase NEDD4-2. J Biol Chem 2020; 295:18148-18159. [PMID: 33093176 PMCID: PMC7939464 DOI: 10.1074/jbc.ra120.015216] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 10/20/2020] [Indexed: 01/14/2023] Open
Abstract
The QT interval is a recording of cardiac electrical activity. Previous genome-wide association studies identified genetic variants that modify the QT interval upstream of LITAF (lipopolysaccharide-induced tumor necrosis factor-α factor), a protein encoding a regulator of endosomal trafficking. However, it was not clear how LITAF might impact cardiac excitation. We investigated the effect of LITAF on the voltage-gated sodium channel Nav1.5, which is critical for cardiac depolarization. We show that overexpressed LITAF resulted in a significant increase in the density of Nav1.5-generated voltage-gated sodium current INa and Nav1.5 surface protein levels in rabbit cardiomyocytes and in HEK cells stably expressing Nav1.5. Proximity ligation assays showed co-localization of endogenous LITAF and Nav1.5 in cardiomyocytes, whereas co-immunoprecipitations confirmed they are in the same complex when overexpressed in HEK cells. In vitro data suggest that LITAF interacts with the ubiquitin ligase NEDD4-2, a regulator of Nav1.5. LITAF overexpression down-regulated NEDD4-2 in cardiomyocytes and HEK cells. In HEK cells, LITAF increased ubiquitination and proteasomal degradation of co-expressed NEDD4-2 and significantly blunted the negative effect of NEDD4-2 on INa We conclude that LITAF controls cardiac excitability by promoting degradation of NEDD4-2, which is essential for removal of surface Nav1.5. LITAF-knockout zebrafish showed increased variation in and a nonsignificant 15% prolongation of action potential duration. Computer simulations using a rabbit-cardiomyocyte model demonstrated that changes in Ca2+ and Na+ homeostasis are responsible for the surprisingly modest action potential duration shortening. These computational data thus corroborate findings from several genome-wide association studies that associated LITAF with QT interval variation.
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Affiliation(s)
- Nilüfer N Turan
- Cardiovascular Research Center, Division of Cardiology, Department of Medicine, Rhode Island Hospital, Warren Alpert Medical School, Brown University, Providence, Rhode Island, USA
| | - Karni S Moshal
- Cardiovascular Research Center, Division of Cardiology, Department of Medicine, Rhode Island Hospital, Warren Alpert Medical School, Brown University, Providence, Rhode Island, USA
| | - Karim Roder
- Cardiovascular Research Center, Division of Cardiology, Department of Medicine, Rhode Island Hospital, Warren Alpert Medical School, Brown University, Providence, Rhode Island, USA
| | - Brett C Baggett
- Cardiovascular Research Center, Division of Cardiology, Department of Medicine, Rhode Island Hospital, Warren Alpert Medical School, Brown University, Providence, Rhode Island, USA
| | - Anatoli Y Kabakov
- Cardiovascular Research Center, Division of Cardiology, Department of Medicine, Rhode Island Hospital, Warren Alpert Medical School, Brown University, Providence, Rhode Island, USA
| | - Saroj Dhakal
- Physics Department and Center for Interdisciplinary Research on Complex Systems, Northeastern University, Boston, Massachusetts, USA
| | - Ryota Teramoto
- Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - David Yi-Eng Chiang
- Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Mingwang Zhong
- Physics Department and Center for Interdisciplinary Research on Complex Systems, Northeastern University, Boston, Massachusetts, USA
| | - An Xie
- Cardiovascular Division, Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA
| | - Yichun Lu
- Cardiovascular Research Center, Division of Cardiology, Department of Medicine, Rhode Island Hospital, Warren Alpert Medical School, Brown University, Providence, Rhode Island, USA
| | - Samuel C Dudley
- Cardiovascular Division, Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA
| | - Calum A MacRae
- Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Alain Karma
- Physics Department and Center for Interdisciplinary Research on Complex Systems, Northeastern University, Boston, Massachusetts, USA
| | - Gideon Koren
- Cardiovascular Research Center, Division of Cardiology, Department of Medicine, Rhode Island Hospital, Warren Alpert Medical School, Brown University, Providence, Rhode Island, USA.
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16
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Edgar JR, Ho AK, Laurá M, Horvath R, Reilly MM, Luzio JP, Roberts RC. A dysfunctional endolysosomal pathway common to two sub-types of demyelinating Charcot-Marie-Tooth disease. Acta Neuropathol Commun 2020; 8:165. [PMID: 33059769 PMCID: PMC7559459 DOI: 10.1186/s40478-020-01043-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 09/24/2020] [Indexed: 12/17/2022] Open
Abstract
Autosomal dominant mutations in LITAF are responsible for the rare demyelinating peripheral neuropathy, Charcot-Marie-Tooth disease type 1C (CMT1C). The LITAF protein is expressed in many human cell types and we have investigated the consequences of two different LITAF mutations in primary fibroblasts from CMT1C patients using confocal and electron microscopy. We observed the appearance of vacuolation/enlargement of late endocytic compartments (late endosomes and lysosomes). This vacuolation was also observed after knocking out LITAF from either control human fibroblasts or from the CMT1C patient-derived cells, consistent with it being the result of loss-of-function mutations in the CMT1C fibroblasts. The vacuolation was similar to that previously observed in fibroblasts from CMT4J patients, which have autosomal recessive mutations in FIG4. The FIG4 protein is a component of a phosphoinositide kinase complex that synthesises phosphatidylinositol 3,5-bisphosphate on the limiting membrane of late endosomes. Phosphatidylinositol 3,5-bisphosphate activates the release of lysosomal Ca2+ through the cation channel TRPML1, which is required to maintain the homeostasis of endosomes and lysosomes in mammalian cells. We observed that a small molecule activator of TRPML1, ML-SA1, was able to rescue the vacuolation phenotype of LITAF knockout, FIG4 knockout and CMT1C patient fibroblasts. Our data describe the first cellular phenotype common to two different subtypes of demyelinating CMT and are consistent with LITAF and FIG4 functioning on a common endolysosomal pathway that is required to maintain the homeostasis of late endosomes and lysosomes. Although our experiments were on human fibroblasts, they have implications for our understanding of the molecular pathogenesis and approaches to therapy in two subtypes of demyelinating Charcot-Marie-Tooth disease.
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Affiliation(s)
- James R Edgar
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge Biomedical Campus, Cambridge, CB2 0XY, UK.
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QP, UK.
| | - Anita K Ho
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge Biomedical Campus, Cambridge, CB2 0XY, UK
- Department of Biology, University of York, York, YO10 5DD, UK
| | - Matilde Laurá
- Centre for Neuromuscular Diseases, UCL, Queen Square Institute of Neurology, University College London, London, WC1N 3BG, UK
| | - Rita Horvath
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, CB2 0PY, UK
| | - Mary M Reilly
- Centre for Neuromuscular Diseases, UCL, Queen Square Institute of Neurology, University College London, London, WC1N 3BG, UK
| | - J Paul Luzio
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge Biomedical Campus, Cambridge, CB2 0XY, UK
| | - Rhys C Roberts
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge Biomedical Campus, Cambridge, CB2 0XY, UK.
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, CB2 0PY, UK.
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17
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Li Z, Farias FHG, Dube U, Del-Aguila JL, Mihindukulasuriya KA, Fernandez MV, Ibanez L, Budde JP, Wang F, Lake AM, Deming Y, Perez J, Yang C, Bahena JA, Qin W, Bradley JL, Davenport R, Bergmann K, Morris JC, Perrin RJ, Benitez BA, Dougherty JD, Harari O, Cruchaga C. The TMEM106B FTLD-protective variant, rs1990621, is also associated with increased neuronal proportion. Acta Neuropathol 2020; 139:45-61. [PMID: 31456032 PMCID: PMC6942643 DOI: 10.1007/s00401-019-02066-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 08/03/2019] [Accepted: 08/19/2019] [Indexed: 12/14/2022]
Abstract
Apart from amyloid β deposition and tau neurofibrillary tangles, Alzheimer's disease (AD) is a neurodegenerative disorder characterized by neuronal loss and astrocytosis in the cerebral cortex. The goal of this study is to investigate genetic factors associated with the neuronal proportion in health and disease. To identify cell-autonomous genetic variants associated with neuronal proportion in cortical tissues, we inferred cellular population structure from bulk RNA-Seq derived from 1536 individuals. We identified the variant rs1990621 located in the TMEM106B gene region as significantly associated with neuronal proportion (p value = 6.40 × 10-07) and replicated this finding in an independent dataset (p value = 7.41 × 10-04) surpassing the genome-wide threshold in the meta-analysis (p value = 9.42 × 10-09). This variant is in high LD with the TMEM106B non-synonymous variant p.T185S (rs3173615; r2 = 0.98) which was previously identified as a protective variant for frontotemporal lobar degeneration (FTLD). We stratified the samples by disease status, and discovered that this variant modulates neuronal proportion not only in AD cases, but also several neurodegenerative diseases and in elderly cognitively healthy controls. Furthermore, we did not find a significant association in younger controls or schizophrenia patients, suggesting that this variant might increase neuronal survival or confer resilience to the neurodegenerative process. The single variant and gene-based analyses also identified an overall genetic association between neuronal proportion, AD and FTLD risk. These results suggest that common pathways are implicated in these neurodegenerative diseases, that implicate neuronal survival. In summary, we identified a protective variant in the TMEM106B gene that may have a neuronal protection effect against general aging, independent of disease status, which could help elucidate the relationship between aging and neuronal survival in the presence or absence of neurodegenerative disorders. Our findings suggest that TMEM106B could be a potential target for neuronal protection therapies to ameliorate cognitive and functional deficits.
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Affiliation(s)
- Zeran Li
- Department of Psychiatry, BJC Institute of Heath, Washington University School of Medicine, 425 S. Euclid Ave., Box 8134, St. Louis, MO, 63110, USA
- NeuroGenomics and Informatics, Washington University School of Medicine, St. Louis, MO, USA
- Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, USA
| | - Fabiana H G Farias
- Department of Psychiatry, BJC Institute of Heath, Washington University School of Medicine, 425 S. Euclid Ave., Box 8134, St. Louis, MO, 63110, USA
- NeuroGenomics and Informatics, Washington University School of Medicine, St. Louis, MO, USA
- Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, USA
| | - Umber Dube
- Department of Psychiatry, BJC Institute of Heath, Washington University School of Medicine, 425 S. Euclid Ave., Box 8134, St. Louis, MO, 63110, USA
- NeuroGenomics and Informatics, Washington University School of Medicine, St. Louis, MO, USA
- Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, USA
| | - Jorge L Del-Aguila
- Department of Psychiatry, BJC Institute of Heath, Washington University School of Medicine, 425 S. Euclid Ave., Box 8134, St. Louis, MO, 63110, USA
- NeuroGenomics and Informatics, Washington University School of Medicine, St. Louis, MO, USA
- Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, USA
| | - Kathie A Mihindukulasuriya
- Department of Psychiatry, BJC Institute of Heath, Washington University School of Medicine, 425 S. Euclid Ave., Box 8134, St. Louis, MO, 63110, USA
- NeuroGenomics and Informatics, Washington University School of Medicine, St. Louis, MO, USA
- Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, USA
| | - Maria Victoria Fernandez
- Department of Psychiatry, BJC Institute of Heath, Washington University School of Medicine, 425 S. Euclid Ave., Box 8134, St. Louis, MO, 63110, USA
- NeuroGenomics and Informatics, Washington University School of Medicine, St. Louis, MO, USA
- Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, USA
| | - Laura Ibanez
- Department of Psychiatry, BJC Institute of Heath, Washington University School of Medicine, 425 S. Euclid Ave., Box 8134, St. Louis, MO, 63110, USA
- NeuroGenomics and Informatics, Washington University School of Medicine, St. Louis, MO, USA
- Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, USA
| | - John P Budde
- Department of Psychiatry, BJC Institute of Heath, Washington University School of Medicine, 425 S. Euclid Ave., Box 8134, St. Louis, MO, 63110, USA
- NeuroGenomics and Informatics, Washington University School of Medicine, St. Louis, MO, USA
- Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, USA
| | - Fengxian Wang
- Department of Psychiatry, BJC Institute of Heath, Washington University School of Medicine, 425 S. Euclid Ave., Box 8134, St. Louis, MO, 63110, USA
- NeuroGenomics and Informatics, Washington University School of Medicine, St. Louis, MO, USA
- Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, USA
| | - Allison M Lake
- Vanderbilt University Medical Scientist Training Program, Nashville, TN, USA
| | - Yuetiva Deming
- Department of Medicine, University of Wisconsin-Madison, Madison, WI, USA
| | - James Perez
- Department of Psychiatry, BJC Institute of Heath, Washington University School of Medicine, 425 S. Euclid Ave., Box 8134, St. Louis, MO, 63110, USA
- NeuroGenomics and Informatics, Washington University School of Medicine, St. Louis, MO, USA
- Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, USA
| | - Chengran Yang
- Department of Psychiatry, BJC Institute of Heath, Washington University School of Medicine, 425 S. Euclid Ave., Box 8134, St. Louis, MO, 63110, USA
- NeuroGenomics and Informatics, Washington University School of Medicine, St. Louis, MO, USA
- Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, USA
| | - Jorge A Bahena
- Department of Psychiatry, BJC Institute of Heath, Washington University School of Medicine, 425 S. Euclid Ave., Box 8134, St. Louis, MO, 63110, USA
- NeuroGenomics and Informatics, Washington University School of Medicine, St. Louis, MO, USA
- Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, USA
| | - Wei Qin
- Department of Psychiatry, BJC Institute of Heath, Washington University School of Medicine, 425 S. Euclid Ave., Box 8134, St. Louis, MO, 63110, USA
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Joseph L Bradley
- Department of Psychiatry, BJC Institute of Heath, Washington University School of Medicine, 425 S. Euclid Ave., Box 8134, St. Louis, MO, 63110, USA
- NeuroGenomics and Informatics, Washington University School of Medicine, St. Louis, MO, USA
- Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, USA
| | - Richard Davenport
- Department of Psychiatry, BJC Institute of Heath, Washington University School of Medicine, 425 S. Euclid Ave., Box 8134, St. Louis, MO, 63110, USA
- NeuroGenomics and Informatics, Washington University School of Medicine, St. Louis, MO, USA
- Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, USA
| | - Kristy Bergmann
- Department of Psychiatry, BJC Institute of Heath, Washington University School of Medicine, 425 S. Euclid Ave., Box 8134, St. Louis, MO, 63110, USA
- NeuroGenomics and Informatics, Washington University School of Medicine, St. Louis, MO, USA
- Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, USA
| | - John C Morris
- Department of Psychiatry, BJC Institute of Heath, Washington University School of Medicine, 425 S. Euclid Ave., Box 8134, St. Louis, MO, 63110, USA
- The Charles F. and Joanne Knight Alzheimer Disease Research Center, Washington University School of Medicine, St. Louis, MO, USA
| | - Richard J Perrin
- Department of Psychiatry, BJC Institute of Heath, Washington University School of Medicine, 425 S. Euclid Ave., Box 8134, St. Louis, MO, 63110, USA
- The Charles F. and Joanne Knight Alzheimer Disease Research Center, Washington University School of Medicine, St. Louis, MO, USA
| | - Bruno A Benitez
- Department of Psychiatry, BJC Institute of Heath, Washington University School of Medicine, 425 S. Euclid Ave., Box 8134, St. Louis, MO, 63110, USA
- NeuroGenomics and Informatics, Washington University School of Medicine, St. Louis, MO, USA
- Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, USA
| | - Joseph D Dougherty
- Department of Psychiatry, BJC Institute of Heath, Washington University School of Medicine, 425 S. Euclid Ave., Box 8134, St. Louis, MO, 63110, USA
| | - Oscar Harari
- Department of Psychiatry, BJC Institute of Heath, Washington University School of Medicine, 425 S. Euclid Ave., Box 8134, St. Louis, MO, 63110, USA
- NeuroGenomics and Informatics, Washington University School of Medicine, St. Louis, MO, USA
- Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, USA
| | - Carlos Cruchaga
- Department of Psychiatry, BJC Institute of Heath, Washington University School of Medicine, 425 S. Euclid Ave., Box 8134, St. Louis, MO, 63110, USA.
- NeuroGenomics and Informatics, Washington University School of Medicine, St. Louis, MO, USA.
- Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, USA.
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18
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Moshal KS, Roder K, Kabakov AY, Werdich AA, Yi-Eng Chiang D, Turan NN, Xie A, Kim TY, Cooper LL, Lu Y, Zhong M, Li W, Terentyev D, Choi BR, Karma A, MacRae CA, Koren G. LITAF (Lipopolysaccharide-Induced Tumor Necrosis Factor) Regulates Cardiac L-Type Calcium Channels by Modulating NEDD (Neural Precursor Cell Expressed Developmentally Downregulated Protein) 4-1 Ubiquitin Ligase. CIRCULATION. GENOMIC AND PRECISION MEDICINE 2019; 12:407-420. [PMID: 31462068 PMCID: PMC6750970 DOI: 10.1161/circgen.119.002641] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND The turnover of cardiac ion channels underlying action potential duration is regulated by ubiquitination. Genome-wide association studies of QT interval identified several single-nucleotide polymorphisms located in or near genes involved in protein ubiquitination. A genetic variant upstream of LITAF (lipopolysaccharide-induced tumor necrosis factor) gene prompted us to determine its role in modulating cardiac excitation. METHODS Optical mapping was performed in zebrafish hearts to determine Ca2+ transients. Live-cell confocal calcium imaging was performed on adult rabbit cardiomyocytes to determine intracellular Ca2+handling. L-type calcium channel (LTCC) current (ICa,L) was measured using whole-cell recording. To study the effect of LITAF on Cav1.2 (L-type voltage-gated calcium channel 1.2) channel expression, surface biotinylation, and Westerns were performed. LITAF interactions were studied using coimmunoprecipitation and in situ proximity ligation assay. RESULTS LITAF knockdown in zebrafish resulted in a robust increase in calcium transients. Overexpressed LITAF in 3-week-old rabbit cardiomyocytes resulted in a decrease in ICa,L and Cavα1c abundance, whereas LITAF knockdown increased ICa,L and Cavα1c protein. LITAF-overexpressing decreases calcium transients in adult rabbit cardiomyocytes, which was associated with lower Cavα1c levels. In tsA201 cells, overexpressed LITAF downregulated total and surface pools of Cavα1c via increased Cavα1c ubiquitination and its subsequent lysosomal degradation. We observed colocalization between LITAF and LTCC in tsA201 and cardiomyocytes. In tsA201, NEDD (neural precursor cell expressed developmentally downregulated protein) 4-1, but not its catalytically inactive form NEDD4-1-C867A, increased Cavα1c ubiquitination. Cavα1c ubiquitination was further increased by coexpressed LITAF and NEDD4-1 but not NEDD4-1-C867A. NEDD4-1 knockdown abolished the negative effect of LITAF on ICa,L and Cavα1c levels in 3-week-old rabbit cardiomyocytes. Computer simulations demonstrated that a decrease of ICa,L current associated with LITAF overexpression simultaneously shortened action potential duration and decreased calcium transients in rabbit cardiomyocytes. CONCLUSIONS LITAF acts as an adaptor protein promoting NEDD4-1-mediated ubiquitination and subsequent degradation of LTCC, thereby controlling LTCC membrane levels and function and thus cardiac excitation.
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Affiliation(s)
- Karni S. Moshal
- Cardiovascular Research Center, Division of Cardiology, Dept of Medicine, Rhode Island Hospital, The Warren Alpert Medical School, Brown Univ, Providence, RI
| | - Karim Roder
- Cardiovascular Research Center, Division of Cardiology, Dept of Medicine, Rhode Island Hospital, The Warren Alpert Medical School, Brown Univ, Providence, RI
| | - Anatoli Y. Kabakov
- Cardiovascular Research Center, Division of Cardiology, Dept of Medicine, Rhode Island Hospital, The Warren Alpert Medical School, Brown Univ, Providence, RI
| | - Andreas A. Werdich
- Cardiovascular Division, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA
| | - David Yi-Eng Chiang
- Cardiovascular Division, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA
| | - Nilüfer N. Turan
- Cardiovascular Research Center, Division of Cardiology, Dept of Medicine, Rhode Island Hospital, The Warren Alpert Medical School, Brown Univ, Providence, RI
| | - An Xie
- Cardiovascular Research Center, Division of Cardiology, Dept of Medicine, Rhode Island Hospital, The Warren Alpert Medical School, Brown Univ, Providence, RI
| | - Tae Yun Kim
- Cardiovascular Research Center, Division of Cardiology, Dept of Medicine, Rhode Island Hospital, The Warren Alpert Medical School, Brown Univ, Providence, RI
| | | | - Yichun Lu
- Cardiovascular Research Center, Division of Cardiology, Dept of Medicine, Rhode Island Hospital, The Warren Alpert Medical School, Brown Univ, Providence, RI
| | - Mingwang Zhong
- Physics Dept & Center for Interdisciplinary Research in Complex Systems, Northeastern Univ, Boston, MA
| | - Weiyan Li
- Cardiovascular Research Center, Division of Cardiology, Dept of Medicine, Rhode Island Hospital, The Warren Alpert Medical School, Brown Univ, Providence, RI
| | - Dmitry Terentyev
- Cardiovascular Research Center, Division of Cardiology, Dept of Medicine, Rhode Island Hospital, The Warren Alpert Medical School, Brown Univ, Providence, RI
| | - Bum-Rak Choi
- Cardiovascular Research Center, Division of Cardiology, Dept of Medicine, Rhode Island Hospital, The Warren Alpert Medical School, Brown Univ, Providence, RI
| | - Alain Karma
- Physics Dept & Center for Interdisciplinary Research in Complex Systems, Northeastern Univ, Boston, MA
| | - Calum A. MacRae
- Cardiovascular Division, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA
| | - Gideon Koren
- Cardiovascular Research Center, Division of Cardiology, Dept of Medicine, Rhode Island Hospital, The Warren Alpert Medical School, Brown Univ, Providence, RI
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Moriwaki Y, Ohno Y, Ishii T, Takamura Y, Kita Y, Watabe K, Sango K, Tsuji S, Misawa H. SIMPLE binds specifically to PI4P through SIMPLE-like domain and participates in protein trafficking in the trans-Golgi network and/or recycling endosomes. PLoS One 2018; 13:e0199829. [PMID: 29953492 PMCID: PMC6023223 DOI: 10.1371/journal.pone.0199829] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Accepted: 06/14/2018] [Indexed: 01/12/2023] Open
Abstract
Small integral membrane protein of the lysosome/late endosome (SIMPLE) is a 161-amino acid cellular protein that contains a characteristic C-terminal domain known as the SIMPLE-like domain (SLD), which is well conserved among species. Several studies have demonstrated that SIMPLE localizes to the trans-Golgi network (TGN), early endosomes, lysosomes, multivesicular bodies, aggresomes and the plasma membrane. However, the amino acid regions responsible for its subcellular localization have not yet been identified. The SLD resembles the FYVE domain, which binds phosphatidylinositol (3)-phosphate (PI3P) and determines the subcellular localization of FYVE domain-containing proteins. In the present study, we have found that SIMPLE binds specifically to PI4P through its SLD. SIMPLE co-localized with PI4P and Rab11, a marker for recycling endosomes (REs, organelles enriched in PI4P) in both the IMS32 mouse Schwann cell line and Hela cells. Sucrose density-gradient centrifugation revealed that SIMPLE co-fractionated with syntaxin-6 (a TGN marker) and Rab11. We have also found that SIMPLE knockdown impeded recycling of transferrin and of transferrin receptor. Our overall results indicate that SIMPLE may regulate protein trafficking physiologically by localizing to the TGN and/or REs by binding PI4P.
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Affiliation(s)
- Yasuhiro Moriwaki
- Division of Pharmacology, Faculty of Pharmacy, Keio University, Minato-ku, Tokyo, Japan
- * E-mail: (YM); (HM)
| | - Yuho Ohno
- Division of Pharmacology, Faculty of Pharmacy, Keio University, Minato-ku, Tokyo, Japan
| | - Tomohiro Ishii
- Division of Pharmacology, Faculty of Pharmacy, Keio University, Minato-ku, Tokyo, Japan
- Laboratory for Neurodegenerative Pathology, Tokyo Metropolitan Institute of Medical Science, Setagaya-ku, Tokyo, Japan
| | - Yuki Takamura
- Division of Pharmacology, Faculty of Pharmacy, Keio University, Minato-ku, Tokyo, Japan
| | - Yuko Kita
- Division of Pharmacology, Faculty of Pharmacy, Keio University, Minato-ku, Tokyo, Japan
| | - Kazuhiko Watabe
- Laboratory for Neurodegenerative Pathology, Tokyo Metropolitan Institute of Medical Science, Setagaya-ku, Tokyo, Japan
| | - Kazunori Sango
- Diabetic Neuropathy Project, Tokyo Metropolitan Institute of Medical Science, Setagaya-ku, Tokyo, Japan
| | - Shoutaro Tsuji
- Molecular Diagnostics Project, Kanagawa Cancer Center Research Institute, Yokohama, Kanagawa, Japan
| | - Hidemi Misawa
- Division of Pharmacology, Faculty of Pharmacy, Keio University, Minato-ku, Tokyo, Japan
- * E-mail: (YM); (HM)
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Guimarães-Costa R, Iancu Ferfoglia R, Leonard-Louis S, Ziegler F, Magy L, Fournier E, Dubourg O, Bouche P, Maisonobe T, Lacour A, Moerman A, Latour P, Stojkovic T. Phenotypic spectrum of Charcot-Marie-Tooth disease due to LITAF/SIMPLE mutations: a study of 18 patients. Eur J Neurol 2017; 24:530-538. [PMID: 28211240 DOI: 10.1111/ene.13239] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Accepted: 11/30/2016] [Indexed: 01/11/2023]
Abstract
BACKGROUND AND PURPOSE Charcot-Marie-Tooth (CMT) 1C due to mutations in LITAF/SIMPLE is a rare subtype amongst the autosomal dominant demyelinating forms of CMT. Our objective was to report the clinical and electrophysiological characteristics of 18 CMT1C patients and compare them to 20 patients with PMP22 mutations: 10 CMT1A patients and 10 patients with hereditary neuropathy with liability to pressure palsies (HNPP). METHODS Charcot-Marie-Tooth 1C patients were followed-up in referral centres for neuromuscular diseases or were identified by familial survey. All CMT1A and HNPP patients were recruited at the referral centre for neuromuscular diseases of Pitié-Salpêtrière Hospital. RESULTS Two phenotypes were identified amongst 18 CMT1C patients: the classical CMT form ('CMT-like', 11 cases) and a predominantly sensory form ('sensory form', seven cases). The mean CMT neuropathy score was 4.45 in CMT1C patients. Motor nerve conduction velocities in the upper limbs were significantly more reduced in CMT1A than in CMT1C patients. On the other hand, the motor nerve conduction velocity of the median nerve was significantly lower in CMT1C compared to the HNPP group. Distal motor latency was significantly more prolonged in CMT1A patients compared to the CMT1C and HNPP groups, the latter two groups having similar distal motor latency values. Molecular analysis revealed five new LITAF/SIMPLE mutations (Ala111Thr, Gly112Ala, Trp116Arg, Pro135Leu, Arg160Cys). CONCLUSIONS Our study delineates CMT1C as mostly a mild form of neuropathy, and gives clinical and electrophysiological clues differentiating CMT1C from CMT1A and HNPP. Delineating phenotypes in CMT subtypes is important to orient molecular diagnosis and to help to interpret complex molecular findings.
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Affiliation(s)
- R Guimarães-Costa
- Centre de Référence des Maladies Neuromusculaires Paris Est, Institut de Myologie, Hôpital Pitié-Salpêtrière, Paris, France
| | - R Iancu Ferfoglia
- Centre de Référence des Maladies Neuromusculaires Paris Est, Institut de Myologie, Hôpital Pitié-Salpêtrière, Paris, France
| | - S Leonard-Louis
- Centre de Référence des Maladies Neuromusculaires Paris Est, Institut de Myologie, Hôpital Pitié-Salpêtrière, Paris, France
| | - F Ziegler
- Service de Neurologie, Centre Hospitalier Intercommunale de la Haute Saône, Vesoul, France
| | - L Magy
- Centre de Référence Neuropathies Périphérique Rares, CHU de Limoges - Hôpital Dupuytren, Limoges, France
| | - E Fournier
- Département de Neurophysiologie Clinique, Hôpital Pitié-Salpêtrière, Paris, France
| | - O Dubourg
- Centre de Référence des Maladies Neuromusculaires Paris Est, Institut de Myologie, Hôpital Pitié-Salpêtrière, Paris, France
| | - P Bouche
- Département de Neurophysiologie Clinique, Hôpital Pitié-Salpêtrière, Paris, France
| | - T Maisonobe
- Département de Neurophysiologie Clinique, Hôpital Pitié-Salpêtrière, Paris, France
| | - A Lacour
- Clinique Neurologique, Centre Hospitalier Universitaire de Lille, Lille, France
| | - A Moerman
- Département de Génétique Médicale, Hôpital Jeanne de Flandres, Centre Hospitalier Universitaire de Lille, Lille, France
| | - P Latour
- Service de Neurobiologie, Centre de Biologie et Pathologie Est, Centre Hospitalier Universitaire de Lyon HCL, GH Est, Lyon, France
| | - T Stojkovic
- Centre de Référence des Maladies Neuromusculaires Paris Est, Institut de Myologie, Hôpital Pitié-Salpêtrière, Paris, France
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21
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GILP family: a stress-responsive group of plant proteins containing a LITAF motif. Funct Integr Genomics 2017; 18:55-66. [DOI: 10.1007/s10142-017-0574-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Revised: 08/04/2017] [Accepted: 09/15/2017] [Indexed: 10/18/2022]
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22
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Ho AK, Wagstaff JL, Manna PT, Wartosch L, Qamar S, Garman EF, Freund SMV, Roberts RC. The topology, structure and PE interaction of LITAF underpin a Charcot-Marie-Tooth disease type 1C. BMC Biol 2016; 14:109. [PMID: 27927196 PMCID: PMC5142333 DOI: 10.1186/s12915-016-0332-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Accepted: 11/16/2016] [Indexed: 02/03/2023] Open
Abstract
Background Mutations in Lipopolysaccharide-induced tumour necrosis factor-α factor (LITAF) cause the autosomal dominant inherited peripheral neuropathy, Charcot-Marie-Tooth disease type 1C (CMT1C). LITAF encodes a 17 kDa protein containing an N-terminal proline-rich region followed by an evolutionarily-conserved C-terminal ‘LITAF domain’, which contains all reported CMT1C-associated pathogenic mutations. Results Here, we report the first structural characterisation of LITAF using biochemical, cell biological, biophysical and NMR spectroscopic approaches. Our structural model demonstrates that LITAF is a monotopic zinc-binding membrane protein that embeds into intracellular membranes via a predicted hydrophobic, in-plane, helical anchor located within the LITAF domain. We show that specific residues within the LITAF domain interact with phosphoethanolamine (PE) head groups, and that the introduction of the V144M CMT1C-associated pathogenic mutation leads to protein aggregation in the presence of PE. Conclusions In addition to the structural characterisation of LITAF, these data lead us to propose that an aberrant LITAF-PE interaction on the surface of intracellular membranes contributes to the molecular pathogenesis that underlies this currently incurable disease. Electronic supplementary material The online version of this article (doi:10.1186/s12915-016-0332-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Anita K Ho
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge Biomedical Campus, Cambridge, CB2 0XY, UK
| | - Jane L Wagstaff
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge, CB2 0QH, UK
| | - Paul T Manna
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge Biomedical Campus, Cambridge, CB2 0XY, UK
| | - Lena Wartosch
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge Biomedical Campus, Cambridge, CB2 0XY, UK
| | - Seema Qamar
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge Biomedical Campus, Cambridge, CB2 0XY, UK
| | - Elspeth F Garman
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
| | - Stefan M V Freund
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge, CB2 0QH, UK
| | - Rhys C Roberts
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge Biomedical Campus, Cambridge, CB2 0XY, UK.
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23
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Hu B, Arpag S, Zuchner S, Li J. A novel missense mutation of CMT2P alters transcription machinery. Ann Neurol 2016; 80:834-845. [PMID: 27615052 DOI: 10.1002/ana.24776] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 08/29/2016] [Accepted: 09/01/2016] [Indexed: 01/01/2023]
Abstract
OBJECTIVE Charcot-Marie-Tooth type 2P (CMT2P) has been associated with frameshift mutations in the RING domain of LRSAM1 (an E3 ligase). This study describes families with a novel missense mutation of LRSAM1 gene and explores pathogenic mechanisms of CMT2P. METHODS Patients with CMT2P were characterized clinically, electrophysiologically, and genetically. A neuronal model with the LRSAM1 mutation was created using CRISPR/Cas9 technology. The neuronal cell line along with fibroblasts isolated from the patients was used to study RNA-binding proteins. RESULTS This American family with dominantly inherited axonal polyneuropathy reveals a phenotype similar to those in previously reported non-US families. The affected members in our family cosegregated with a novel missense mutation Cys694Arg that alters a highly conserved cysteine in the RING domain. This mutation leads to axonal degeneration in the in vitro neuronal cell line. Moreover, using protein mass spectrometry, we identified a group of RNA-binding proteins (including FUS, a protein critically involved in motor neuron degeneration) that interacted with LRSAM1. The interactions were disrupted by the Cys694Arg mutation, which resulted in reduction of intranuclear RNA-binding proteins. INTERPRETATION Our findings suggest that the mutant LRSAM1 may aberrantly affect the formation of transcription machinery. Given that a similar mechanism has been reported in motor neuron degeneration of amyotrophic lateral sclerosis, abnormalities of RNA/RNA-binding protein complex may play a role in the neuronal degeneration of CMT2P. Ann Neurol 2016;80:834-845.
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Affiliation(s)
- Bo Hu
- Department of Neurology, Center for Human Genetic Research, and Vanderbilt Brain Institute, Vanderbilt University School of Medicine, Nashville, TN
| | - Sezgi Arpag
- Department of Neurology, Center for Human Genetic Research, and Vanderbilt Brain Institute, Vanderbilt University School of Medicine, Nashville, TN
| | - Stephan Zuchner
- Department of Human Genetics and Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL
| | - Jun Li
- Department of Neurology, Center for Human Genetic Research, and Vanderbilt Brain Institute, Vanderbilt University School of Medicine, Nashville, TN
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24
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The Charcot Marie Tooth disease protein LITAF is a zinc-binding monotopic membrane protein. Biochem J 2016; 473:3965-3978. [PMID: 27582497 PMCID: PMC5095921 DOI: 10.1042/bcj20160657] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Accepted: 08/31/2016] [Indexed: 01/11/2023]
Abstract
LITAF (LPS-induced TNF-activating factor) is an endosome-associated integral membrane protein important for multivesicular body sorting. Several mutations in LITAF cause autosomal-dominant Charcot Marie Tooth disease type 1C. These mutations map to a highly conserved C-terminal region, termed the LITAF domain, which includes a 22 residue hydrophobic sequence and flanking cysteine-rich regions that contain peptide motifs found in zinc fingers. Although the LITAF domain is thought to be responsible for membrane integration, the membrane topology of LITAF has not been established. Here, we have investigated whether LITAF is a tail-anchored (TA) membrane-spanning protein or monotopic membrane protein. When translated in vitro, LITAF integrates poorly into ER-derived microsomes compared with Sec61β, a bona fide TA protein. Furthermore, introduction of N-linked glycosylation reporters shows that neither the N-terminal nor C-terminal domains of LITAF translocate into the ER lumen. Expression in cells of an LITAF construct containing C-terminal glycosylation sites confirms that LITAF is not a TA protein in cells. Finally, an immunofluorescence-based latency assay showed that both the N- and C-termini of LITAF are exposed to the cytoplasm. Recombinant LITAF contains 1 mol/mol zinc, while mutation of predicted zinc-binding residues disrupts LITAF membrane association. Hence, we conclude that LITAF is a monotopic membrane protein whose membrane integration is stabilised by a zinc finger. The related human protein, CDIP1 (cell death involved p53 target 1), displays identical membrane topology, suggesting that this mode of membrane integration is conserved in LITAF family proteins.
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Setti M, Osti D, Richichi C, Ortensi B, Del Bene M, Fornasari L, Beznoussenko G, Mironov A, Rappa G, Cuomo A, Faretta M, Bonaldi T, Lorico A, Pelicci G. Extracellular vesicle-mediated transfer of CLIC1 protein is a novel mechanism for the regulation of glioblastoma growth. Oncotarget 2016; 6:31413-27. [PMID: 26429879 PMCID: PMC4741615 DOI: 10.18632/oncotarget.5105] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Accepted: 09/18/2015] [Indexed: 01/09/2023] Open
Abstract
Little progresses have been made in the treatment of glioblastoma (GBM), the most aggressive and lethal among brain tumors. Recently we have demonstrated that Chloride Intracellular Channel-1 (CLIC1) is overexpressed in GBM compared to normal tissues, with highest expression in patients with poor prognosis. Moreover, CLIC1-silencing in cancer stem cells (CSCs) isolated from human GBM patients negatively influences proliferative capacity and self-renewal properties in vitro and impairs the in vivo tumorigenic potential. Here we show that CLIC1 exists also as a circulating protein, secreted via extracellular vesicles (EVs) released by either cell lines or GBM-derived CSCs. Extracellular vesicles (EVs), comprising exosomes and microvesicles based on their composition and biophysical properties, have been shown to sustain tumor growth in a variety of model systems, including GBM. Interestingly, treatment of GBM cells with CLIC1-containing EVs stimulates cell growth both in vitro and in vivo in a CLIC1-dose dependent manner. EVs derived from CLIC1-overexpressing GBM cells are strong inducers of proliferation in vitro and tumor engraftment in vivo. These stimulations are significantly attenuated by treatment of GBM cells with EVs derived from CLIC1-silenced cells. However, CLIC1 modulation appears to have no direct role in EV structure, biogenesis and secretion. These findings reveal that, apart from the function of CLIC1 cellular reservoir, CLIC1 contained in EVs is a novel regulator of GBM growth.
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Affiliation(s)
- Matteo Setti
- Department of Experimental Oncology, European Institute of Oncology, Milan, Italy
| | - Daniela Osti
- Department of Experimental Oncology, European Institute of Oncology, Milan, Italy
| | - Cristina Richichi
- Department of Experimental Oncology, European Institute of Oncology, Milan, Italy
| | - Barbara Ortensi
- Department of Experimental Oncology, European Institute of Oncology, Milan, Italy
| | - Massimiliano Del Bene
- Department of Neurosurgery, Fondazione IRCCS Istituto Neurologico C. Besta, Milan, Italy
| | - Lorenzo Fornasari
- Department of Experimental Oncology, European Institute of Oncology, Milan, Italy
| | - Galina Beznoussenko
- Institute of Molecular Oncology (IFOM) of The Italian Foundation for Cancer Research (FIRC), Milan, Italy
| | - Alexandre Mironov
- Institute of Molecular Oncology (IFOM) of The Italian Foundation for Cancer Research (FIRC), Milan, Italy
| | - Germana Rappa
- Department of Experimental Oncology, European Institute of Oncology, Milan, Italy
| | - Alessandro Cuomo
- Department of Experimental Oncology, European Institute of Oncology, Milan, Italy
| | - Mario Faretta
- Department of Experimental Oncology, European Institute of Oncology, Milan, Italy
| | - Tiziana Bonaldi
- Department of Experimental Oncology, European Institute of Oncology, Milan, Italy
| | - Aurelio Lorico
- Cancer Research Center, Roseman University of Health Sciences with Roseman University College of Medicine, Las Vegas, NV, USA
| | - Giuliana Pelicci
- Department of Experimental Oncology, European Institute of Oncology, Milan, Italy.,Department of Translational Medicine, Università del Piemonte Orientale, Novara, Italy
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Chen YS, Chen NN, Qin XW, Mi S, He J, Lin YF, Gao MS, Weng SP, Guo CJ, He JG. Tiger frog virus ORF080L protein interacts with LITAF and impairs EGF-induced EGFR degradation. Virus Res 2016; 217:133-42. [PMID: 26956473 DOI: 10.1016/j.virusres.2016.03.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Revised: 02/23/2016] [Accepted: 03/02/2016] [Indexed: 10/22/2022]
Abstract
Tiger frog virus (TFV) belongs to the genus Ranavirus, family Iridoviridae, and causes severe mortality in commercial cultures in China. TFV ORF080L is a gene homolog of lipopolysaccharide-induced TNF-α factor (LITAF), which is a regulator in endosome-to-lysosome trafficking through its function in the endosomal sorting complex required for transport machinery. The characteristics and biological roles of TFV ORF080L were identified. TFV ORF080L was predicted to encode an 84-amino acid peptide (VP080L). It had high-sequence identity with mammalian LITAF, but lacked the N-terminus of LITAF, which contains two PPXY motifs. Transcription and protein level analyses showed that TFV ORF080L was a late viral gene. Localization in the virons also showed that TFV VP080L was a viral structural protein. Immunofluorescence staining showed that TFV ORF080L was predominantly colocalized with plasma membrane and partly distributed with the late endosome in infected HepG2 cells. SiRNA-mediated TFV ORF080L silencing decreased viral reproduction. Moreover, TFV ORF080L interacted with human/zebrafish LITAF and impaired EGF-induced EGFR degradation, thereby indicating that TFV ORF080L played a role in endosome-to-lysosome trafficking. These findings suggested that TFV ORF080L might negate the function of cellular LITAF to impair endosomal sorting and trafficking. Results provide a clue to the link between the dysregulated endosomal trafficking and iridovirus pathogenesis.
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Affiliation(s)
- Yong-Shun Chen
- MOE Key Laboratory of Aquatic Product Safety/State Key Laboratory for Biocontrol, School of Life Sciences, Sun Yat-sen University, 135 Xingang Road West, Guangzhou 510275, PR China
| | - Nan-Nan Chen
- Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering/South China Sea Bio-Resource Exploitation and Utilization Collaborative Innovation Center, School of Marine, Sun Yat-sen University, 135 Xingang Road West, Guangzhou 510275, PR China; MOE Key Laboratory of Aquatic Product Safety/State Key Laboratory for Biocontrol, School of Life Sciences, Sun Yat-sen University, 135 Xingang Road West, Guangzhou 510275, PR China
| | - Xiao-Wei Qin
- MOE Key Laboratory of Aquatic Product Safety/State Key Laboratory for Biocontrol, School of Life Sciences, Sun Yat-sen University, 135 Xingang Road West, Guangzhou 510275, PR China
| | - Shu Mi
- Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering/South China Sea Bio-Resource Exploitation and Utilization Collaborative Innovation Center, School of Marine, Sun Yat-sen University, 135 Xingang Road West, Guangzhou 510275, PR China
| | - Jian He
- Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering/South China Sea Bio-Resource Exploitation and Utilization Collaborative Innovation Center, School of Marine, Sun Yat-sen University, 135 Xingang Road West, Guangzhou 510275, PR China
| | - Yi-Fan Lin
- Institute of Aquatic Economic Animals and Guangdong Province Key Laboratory for Aquatic Economic Animals, Sun Yat-sen University, 135 Xingang Road West, Guangzhou 510275, PR China
| | - Ming-Shi Gao
- MOE Key Laboratory of Aquatic Product Safety/State Key Laboratory for Biocontrol, School of Life Sciences, Sun Yat-sen University, 135 Xingang Road West, Guangzhou 510275, PR China
| | - Shao-Ping Weng
- MOE Key Laboratory of Aquatic Product Safety/State Key Laboratory for Biocontrol, School of Life Sciences, Sun Yat-sen University, 135 Xingang Road West, Guangzhou 510275, PR China
| | - Chang-Jun Guo
- Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering/South China Sea Bio-Resource Exploitation and Utilization Collaborative Innovation Center, School of Marine, Sun Yat-sen University, 135 Xingang Road West, Guangzhou 510275, PR China; MOE Key Laboratory of Aquatic Product Safety/State Key Laboratory for Biocontrol, School of Life Sciences, Sun Yat-sen University, 135 Xingang Road West, Guangzhou 510275, PR China.
| | - Jian-Guo He
- MOE Key Laboratory of Aquatic Product Safety/State Key Laboratory for Biocontrol, School of Life Sciences, Sun Yat-sen University, 135 Xingang Road West, Guangzhou 510275, PR China
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Dysregulated Inflammatory Signaling upon Charcot-Marie-Tooth Type 1C Mutation of SIMPLE Protein. Mol Cell Biol 2015; 35:2464-78. [PMID: 25963657 DOI: 10.1128/mcb.00300-15] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Endosomal trafficking is a key mechanism to modulate signal propagation and cross talk. Ubiquitin adaptors, along with endosomal sorting complex required for transport (ESCRT) complexes, are also integrated to terminate ligand-receptor activation in late endosomes and multivesicular bodies (MVBs). Within these pathways, we recently demonstrated that the protein SIMPLE is a novel player in MVB regulation. SIMPLE is also clinically important and its mutation accounts for the Charcot-Marie-Tooth type 1C (CMT1C) disease. MVB defects of mutation and deletion of SIMPLE, however, are distinct. Here, we show that MVB defects found in mutation but not deletion of SIMPLE lead to impaired turnover and accumulation of ESCRT-0 protein Hrs punctain late endosomes. We further uncover increased colocalization of ubiquitin ligase TRAF6 and Hrs in late endosomes. Upon stimulation with interkeukin-1 or transforming growth factor , prolonged activation of p38 kinase/JNK is detected, while nuclear accumulation of NF-κB and phosphorylation of SMAD2 is reduced with CMT1C mutation. The aberrant kinetics we observed in inflammatory signaling may contribute to increased tumor susceptibility and changes in the levels of chemokines/cytokines that result from CMT1C mutation. We propose that altered endosomal trafficking due to malformations of MVBs and subsequent atypical signaling kinetic may account for a toxic gain of function in CMT1C pathogenesis.
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ZOU JUNRONG, GUO PEI, LV NONGHUA, HUANG DEQIANG. Lipopolysaccharide-induced tumor necrosis factor-α factor enhances inflammation and is associated with cancer (Review). Mol Med Rep 2015; 12:6399-404. [DOI: 10.3892/mmr.2015.4243] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2014] [Accepted: 06/03/2015] [Indexed: 11/06/2022] Open
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Roder K, Werdich AA, Li W, Liu M, Kim TY, Organ-Darling LE, Moshal KS, Hwang JM, Lu Y, Choi BR, MacRae CA, Koren G. RING finger protein RNF207, a novel regulator of cardiac excitation. J Biol Chem 2014; 289:33730-40. [PMID: 25281747 DOI: 10.1074/jbc.m114.592295] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Two recent studies (Newton-Cheh, C. et al. (2009) Common variants at ten loci influence QT interval duration in the QTGEN Study. Nat. Genet. 41, 399-406 and Pfeufer, A. et al. (2009) Common variants at ten loci modulate the QT interval duration in the QTSCD Study. Nat. Genet. 41, 407-414) identified an association, with genome-wide significance, between a single nucleotide polymorphism within the gene encoding RING finger protein 207 (RNF207) and the QT interval. We sought to determine the role of RNF207 in cardiac electrophysiology. Morpholino knockdown of RNF207 in zebrafish embryos resulted in action potential duration prolongation, occasionally a 2:1 atrioventricular block, and slowing of conduction velocity. Conversely, neonatal rabbit cardiomyocytes infected with RNF207-expressing adenovirus exhibited shortened action potential duration. Using transfections of U-2 OS and HEK293 cells, Western blot analysis and immunocytochemistry data demonstrate that RNF207 and the human ether-a-go-go-related gene (HERG) potassium channel interact and colocalize. Furthermore, RNF207 overexpression significantly elevated total and membrane HERG protein and HERG-encoded current density by ∼30-50%, which was dependent on the intact N-terminal RING domain of RNF207. Finally, coexpression of RNF207 and HSP70 increased HERG expression compared with HSP70 alone. This effect was dependent on the C terminus of RNF207. Taken together, the evidence is strong that RNF207 is an important regulator of action potential duration, likely via effects on HERG trafficking and localization in a heat shock protein-dependent manner.
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Affiliation(s)
- Karim Roder
- From the Cardiovascular Research Center, Division of Cardiology, Department of Medicine, Rhode Island Hospital, Warren Alpert Medical School, Brown University, Providence, Rhode Island 02903
| | - Andreas A Werdich
- the Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, and
| | - Weiyan Li
- From the Cardiovascular Research Center, Division of Cardiology, Department of Medicine, Rhode Island Hospital, Warren Alpert Medical School, Brown University, Providence, Rhode Island 02903
| | - Man Liu
- From the Cardiovascular Research Center, Division of Cardiology, Department of Medicine, Rhode Island Hospital, Warren Alpert Medical School, Brown University, Providence, Rhode Island 02903
| | - Tae Yun Kim
- From the Cardiovascular Research Center, Division of Cardiology, Department of Medicine, Rhode Island Hospital, Warren Alpert Medical School, Brown University, Providence, Rhode Island 02903
| | - Louise E Organ-Darling
- the Department of Biological Sciences, Wellesley College, Wellesley, Massachusetts 02481
| | - Karni S Moshal
- From the Cardiovascular Research Center, Division of Cardiology, Department of Medicine, Rhode Island Hospital, Warren Alpert Medical School, Brown University, Providence, Rhode Island 02903
| | - Jung Min Hwang
- From the Cardiovascular Research Center, Division of Cardiology, Department of Medicine, Rhode Island Hospital, Warren Alpert Medical School, Brown University, Providence, Rhode Island 02903
| | - Yichun Lu
- From the Cardiovascular Research Center, Division of Cardiology, Department of Medicine, Rhode Island Hospital, Warren Alpert Medical School, Brown University, Providence, Rhode Island 02903
| | - Bum-Rak Choi
- From the Cardiovascular Research Center, Division of Cardiology, Department of Medicine, Rhode Island Hospital, Warren Alpert Medical School, Brown University, Providence, Rhode Island 02903
| | - Calum A MacRae
- the Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, and
| | - Gideon Koren
- From the Cardiovascular Research Center, Division of Cardiology, Department of Medicine, Rhode Island Hospital, Warren Alpert Medical School, Brown University, Providence, Rhode Island 02903,
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Ferreira Lacerda A, Hartjes E, Brunetti CR. LITAF mutations associated with Charcot-Marie-Tooth disease 1C show mislocalization from the late endosome/lysosome to the mitochondria. PLoS One 2014; 9:e103454. [PMID: 25058650 PMCID: PMC4110028 DOI: 10.1371/journal.pone.0103454] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Accepted: 07/02/2014] [Indexed: 01/01/2023] Open
Abstract
Charcot-Marie-Tooth (CMT) disease is one of the most common heritable neuromuscular disorders, affecting 1 in every 2500 people. Mutations in LITAF have been shown to be causative for CMT type 1C disease. In this paper we explore the subcellular localization of wild type LITAF and mutant forms of LITAF known to cause CMT1C (T49M, A111G, G112S, T115N, W116G, L122V and P135T). The results show that LITAF mutants A111G, G112S, W116G, and T115N mislocalize from the late endosome/lysosome to the mitochondria while the mutants T49M, L122V, and P135T show partial mislocalization with a portion of the total protein present in the late endosome/lysosome and the remainder of the protein localized to the mitochondria. This suggests that different mutants of LITAF will produce differing severity of disease. We also explored the effect of the presence of mutant LITAF on wild-type LITAF localization. We showed that in cells heterozygous for LITAF, CMT1C mutants T49M and G112S are dominant since wild-type LITAF localized to the mitochondria when co-transfected with a LITAF mutant. Finally, we demonstrated how LITAF transits to the endosome and mitochondria compartments of the cell. Using Brefeldin A to block ER to Golgi transport we demonstrated that wild type LITAF traffics through the secretory pathway to the late endosome/lysosome while the LITAF mutants transit to the mitochondria independent of the secretory pathway. In addition, we demonstrated that the C-terminus of LITAF is necessary and sufficient for targeting of wild-type LITAF to the late endosome/lysosome and the mutants to the mitochondria. Together these data provide insight into how mutations in LITAF cause CMT1C disease.
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Affiliation(s)
| | - Emily Hartjes
- Biology Department, Trent University, Peterborough, Ontario, Canada
| | - Craig R. Brunetti
- Biology Department, Trent University, Peterborough, Ontario, Canada
- * E-mail:
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Engeholm M, Sekler J, Schöndorf DC, Arora V, Schittenhelm J, Biskup S, Schell C, Gasser T. A novel mutation in LRSAM1 causes axonal Charcot-Marie-Tooth disease with dominant inheritance. BMC Neurol 2014; 14:118. [PMID: 24894446 PMCID: PMC4060843 DOI: 10.1186/1471-2377-14-118] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Accepted: 05/30/2014] [Indexed: 12/13/2022] Open
Abstract
Background Charcot-Marie-Tooth disease (CMT) refers to a heterogeneous group of genetic motor and sensory neuropathies. According to the primary site of damage, a distinction is made between demyelinating and axonal forms (CMT1 and 2, respectively, when inherited as an autosomal dominant trait). Leucine-rich repeat and sterile alpha motif-containing protein 1 (LRSAM1) is a ubiquitin-protein ligase with a role in sorting internalised cell-surface receptor proteins. So far, mutations in the LRSAM1 gene have been shown to cause axonal CMT in three different families and can confer either dominant or recessive transmission of the disease. Case presentation We have identified a novel mutation in LRSAM1 in a small family with dominant axonal CMT. Electrophysiological studies show evidence of a sensory axonal neuropathy and are interesting in so far as giant motor unit action potentials (MUAPs) are present on needle electromyography (EMG), while motor nerve conduction studies including compound motor action potential (CMAP) amplitudes are completely normal. The underlying mutation c.2046+1G >T results in the loss of a splice donor site and the inclusion of 63 additional base pairs of intronic DNA into the aberrantly spliced transcript. This disrupts the catalytically active RING (Really Interesting New Gene) domain of LRSAM1. Conclusions Our findings suggest that, beyond the typical length-dependent degeneration of motor axons, damage of cell bodies in the anterior horn might play a role in LRSAM1-associated neuropathies. Moreover, in conjunction with other data in the literature, our results support a model, by which disruption of the C-terminal RING domain confers dominant negative properties to LRSAM1.
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Affiliation(s)
- Maik Engeholm
- Department of Neurology and Hertie Institute for Clinical Brain Research, Hoppe-Seyler-Str, 3, 72076 Tübingen, Germany.
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Bogdanik LP, Sleigh JN, Tian C, Samuels ME, Bedard K, Seburn KL, Burgess RW. Loss of the E3 ubiquitin ligase LRSAM1 sensitizes peripheral axons to degeneration in a mouse model of Charcot-Marie-Tooth disease. Dis Model Mech 2013; 6:780-92. [PMID: 23519028 PMCID: PMC3634660 DOI: 10.1242/dmm.010942] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Accepted: 03/06/2013] [Indexed: 01/08/2023] Open
Abstract
Charcot-Marie-Tooth disease (CMT) is a clinically and genetically heterogeneous condition characterized by peripheral axon degeneration with subsequent motor and sensory deficits. Several CMT gene products function in endosomal sorting and trafficking to the lysosome, suggesting that defects in this cellular pathway might present a common pathogenic mechanism for these conditions. LRSAM1 is an E3 ubiquitin ligase that is implicated in this process, and mutations in LRSAM1 have recently been shown to cause CMT. We have generated mouse mutations in Lrsam1 to create an animal model of this form of CMT (CMT2P). Mouse Lrsam1 is abundantly expressed in the motor and sensory neurons of the peripheral nervous system. Both homozygous and heterozygous mice have largely normal neuromuscular performance and only a very mild neuropathy phenotype with age. However, Lrsam1 mutant mice are more sensitive to challenge with acrylamide, a neurotoxic agent that causes axon degeneration, indicating that the axons in the mutant mice are indeed compromised. In transfected cells, LRSAM1 primarily localizes in a perinuclear compartment immediately beyond the Golgi and shows little colocalization with components of the endosome to lysosome trafficking pathway, suggesting that other cellular mechanisms also merit consideration.
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Affiliation(s)
| | - James N. Sleigh
- The Jackson Laboratory, Bar Harbor, ME, 04609, USA
- MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford, OX1 3QX, UK
| | - Cong Tian
- The Jackson Laboratory, Bar Harbor, ME, 04609, USA
- Graduate School of Biomedical Sciences, The University of Maine, Orono, ME 04469, USA
| | - Mark E. Samuels
- Department of Medicine, Montreal University, Montreal, Quebec, H3T 1C5, Canada
| | - Karen Bedard
- Department of Pathology, Dalhousie University, Halifax, Nova Scotia, B3H 4R2, Canada
| | | | - Robert W. Burgess
- The Jackson Laboratory, Bar Harbor, ME, 04609, USA
- Graduate School of Biomedical Sciences, The University of Maine, Orono, ME 04469, USA
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Zhu H, Guariglia S, Yu RYL, Li W, Brancho D, Peinado H, Lyden D, Salzer J, Bennett C, Chow CW. Mutation of SIMPLE in Charcot-Marie-Tooth 1C alters production of exosomes. Mol Biol Cell 2013; 24:1619-37, S1-3. [PMID: 23576546 PMCID: PMC3667717 DOI: 10.1091/mbc.e12-07-0544] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Mutations in the protein SIMPLE account for the rare autosomal-dominant demyelination in type 1C CMT patients (CMT1C). SIMPLE plays a role in the production of exosomes. Dysregulated endosomal trafficking and changes in exosome-mediated intercellular communications might account for CMT1C molecular pathogenesis. Charcot–Marie–Tooth (CMT) disease is an inherited neurological disorder. Mutations in the small integral membrane protein of the lysosome/late endosome (SIMPLE) account for the rare autosomal-dominant demyelination in CMT1C patients. Understanding the molecular basis of CMT1C pathogenesis is impeded, in part, by perplexity about the role of SIMPLE, which is expressed in multiple cell types. Here we show that SIMPLE resides within the intraluminal vesicles of multivesicular bodies (MVBs) and inside exosomes, which are nanovesicles secreted extracellularly. Targeting of SIMPLE to exosomes is modulated by positive and negative regulatory motifs. We also find that expression of SIMPLE increases the number of exosomes and secretion of exosome proteins. We engineer a point mutation on the SIMPLE allele and generate a physiological mouse model that expresses CMT1C-mutated SIMPLE at the endogenous level. We find that CMT1C mouse primary embryonic fibroblasts show decreased number of exosomes and reduced secretion of exosome proteins, in part due to improper formation of MVBs. CMT1C patient B cells and CMT1C mouse primary Schwann cells show similar defects. Together the data indicate that SIMPLE regulates the production of exosomes by modulating the formation of MVBs. Dysregulated endosomal trafficking and changes in the landscape of exosome-mediated intercellular communications may place an overwhelming burden on the nervous system and account for CMT1C molecular pathogenesis.
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Affiliation(s)
- Hong Zhu
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, New York, NY 10461, USA
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34
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Chin LS, Lee SM, Li L. SIMPLE: A new regulator of endosomal trafficking and signaling in health and disease. Commun Integr Biol 2013; 6:e24214. [PMID: 23713142 PMCID: PMC3656027 DOI: 10.4161/cib.24214] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Accepted: 03/06/2013] [Indexed: 12/29/2022] Open
Abstract
SIMPLE, also known as LITAF, EET1 and PIG7, was originally identified based on its transcriptional upregulation by estrogen, p53, lipopolysaccharide or a microbial cell-wall component. Missense mutations in SIMPLE cause Charcot-Marie-Tooth disease (CMT), and altered SIMPLE expression is associated with cancer, obesity and inflammatory bowel diseases. Despite increasing evidence linking SIMPLE to human diseases, the biological function of SIMPLE is unknown and the pathogenic mechanism of SIMPLE mutations remains elusive. Our recent study reveals that SIMPLE is a functional partner of the endosomal sorting complex required for transport (ESCRT) machinery in the regulation of endosome-to-lysosome trafficking and intracellular signaling. Our results indicate that CMT-linked SIMPLE mutants are loss-of-function mutants which act dominantly to impair endosomal trafficking and signaling attenuation. We propose that endosomal trafficking and signaling dysregulation is a key pathogenic mechanism in CMT and other diseases that involve SIMPLE dysfunction.
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Affiliation(s)
- Lih-Shen Chin
- Department of Pharmacology; Emory University School of Medicine; Atlanta, GA USA
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Abstract
The endosomal sorting complexes required for transport (ESCRT) pathway was initially defined in yeast genetic screens that identified the factors necessary to sort membrane proteins into intraluminal endosomal vesicles. Subsequent studies have revealed that the mammalian ESCRT pathway also functions in a series of other key cellular processes, including formation of extracellular microvesicles, enveloped virus budding, and the abscission stage of cytokinesis. The core ESCRT machinery comprises Bro1 family proteins and ESCRT-I, ESCRT-II, ESCRT-III, and VPS4 complexes. Site-specific adaptors recruit these soluble factors to assemble on different cellular membranes, where they carry out membrane fission reactions. ESCRT-III proteins form filaments that draw membranes together from the cytoplasmic face, and mechanistic models have been advanced to explain how ESCRT-III filaments and the VPS4 ATPase can work together to catalyze membrane fission.
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Affiliation(s)
- John McCullough
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, Utah 84112-5650, USA
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36
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Dumaresq-Doiron K, Jules F, Lefrancois S. Sortilin turnover is mediated by ubiquitination. Biochem Biophys Res Commun 2013; 433:90-5. [PMID: 23485461 DOI: 10.1016/j.bbrc.2013.02.059] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Accepted: 02/08/2013] [Indexed: 11/15/2022]
Abstract
Sortilin is a transmembrane domain protein that has been implicated in the sorting of prosaposin and other soluble cargo from the Golgi to the lysosomal compartment. While the majority of the receptor is recycled back to the Golgi from endosomes, it is known that upon successive rounds of transport, a proportion of sortilin is degraded in lysosomes. Recently, it was shown that sortilin is palmitoylated and that this post-translational modification prevents its degradation and enables sortilin to efficiently traffic back to the Golgi. Thus palmitoylation can be used to modulate the amount of receptor and hence cargo reaching the lysosome. In this work, we demonstrate that non-palmitoylated sortilin is ubiquitinated and internalized into the lysosomal compartment via the ESCRT pathway for degradation. Furthermore, we identified Nedd4 as an E3 ubiquitin ligase that mediates this post-translational modification. We propose a model where palmitoylation and ubiquitination play opposite roles in the stability and turnover of sortilin and serve as a control mechanism that balances the amount of lysosomal sorting and trafficking in cells.
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Affiliation(s)
- Karine Dumaresq-Doiron
- Centre de recherche de l'Hôpital Maisonneuve-Rosemont, Université de Montréal, Montréal, QC, Canada H1T 2M4
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Eaton HE, Ferreira Lacerda A, Desrochers G, Metcalf J, Angers A, Brunetti CR. Cellular LITAF interacts with frog virus 3 75L protein and alters its subcellular localization. J Virol 2013; 87:716-23. [PMID: 23097445 PMCID: PMC3554103 DOI: 10.1128/jvi.01857-12] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Accepted: 10/17/2012] [Indexed: 02/06/2023] Open
Abstract
Iridoviruses are a family of large double-stranded DNA (dsDNA) viruses that are composed of 5 genera, including the Lymphocystivirus, Ranavirus, Megalocytivirus, Iridovirus, and Chloriridovirus genera. The frog virus 3 (FV3) 75L gene is a nonessential gene that is highly conserved throughout the members of the Ranavirus genus but is not found in other iridoviruses. FV3 75L shows high sequence similarity to a conserved domain found in the C terminus of LITAF, a small cellular protein with unknown function. Here we show that FV3 75L localizes to early endosomes, while LITAF localizes to late endosomes/lysosomes. Interestingly, when FV3 75L and LITAF are cotransfected into cells, LITAF can alter the subcellular localization of FV3 75L to late endosomes/lysosomes, where FV3 75L then colocalizes with LITAF. In addition, we demonstrated that virally produced 75L colocalizes with LITAF. We confirmed a physical interaction between LITAF and FV3 75L but found that this interaction was not mediated by two PPXY motifs in the N terminus of LITAF. Mutation of two PPXY motifs in LITAF did not affect the colocalization of LITAF and FV3 75L but did change the location of the two proteins from late endosomes/lysosomes to early endosomes.
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Affiliation(s)
- Heather E. Eaton
- Department of Biology, Trent University, Peterborough, Ontario, Canada
| | | | - Guillaume Desrochers
- Département de Sciences Biologiques, Université de Montréal, Montréal, Québec, Canada
| | - Julie Metcalf
- Department of Biology, Trent University, Peterborough, Ontario, Canada
| | - Annie Angers
- Département de Sciences Biologiques, Université de Montréal, Montréal, Québec, Canada
| | - Craig R. Brunetti
- Department of Biology, Trent University, Peterborough, Ontario, Canada
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Masaki T. Polarization and myelination in myelinating glia. ISRN NEUROLOGY 2012; 2012:769412. [PMID: 23326681 PMCID: PMC3544266 DOI: 10.5402/2012/769412] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Accepted: 11/13/2012] [Indexed: 01/13/2023]
Abstract
Myelinating glia, oligodendrocytes in central nervous system and Schwann cells in peripheral nervous system, form myelin sheath, a multilayered membrane system around axons enabling salutatory nerve impulse conduction and maintaining axonal integrity. Myelin sheath is a polarized structure localized in the axonal side and therefore is supposed to be formed based on the preceding polarization of myelinating glia. Thus, myelination process is closely associated with polarization of myelinating glia. However, cell polarization has been less extensively studied in myelinating glia than other cell types such as epithelial cells. The ultimate goal of this paper is to provide insights for the field of myelination research by applying the information obtained in polarity study in other cell types, especially epithelial cells, to cell polarization of myelinating glia. Thus, in this paper, the main aspects of cell polarization study in general are summarized. Then, they will be compared with polarization in oligodendrocytes. Finally, the achievements obtained in polarization study for epithelial cells, oligodendrocytes, and other types of cells will be translated into polarization/myelination process by Schwann cells. Then, based on this model, the perspectives in the study of Schwann cell polarization/myelination will be discussed.
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Affiliation(s)
- Toshihiro Masaki
- Department of Medical Science, Teikyo University of Science, 2-2-1 Senju-Sakuragi, Adachi-ku, Tokyo 120-0045, Japan
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Lee SM, Chin LS, Li L. Charcot-Marie-Tooth disease-linked protein SIMPLE functions with the ESCRT machinery in endosomal trafficking. ACTA ACUST UNITED AC 2012; 199:799-816. [PMID: 23166352 PMCID: PMC3514783 DOI: 10.1083/jcb.201204137] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
SIMPLE functions with the ESCRT machinery to promote endosome-to-lysosome trafficking, and this function is impaired by Charcot-Marie-Tooth disease–associated mutations. Mutations in small integral membrane protein of lysosome/late endosome (SIMPLE) cause autosomal dominant, Charcot-Marie-Tooth disease (CMT) type 1C. The cellular function of SIMPLE is unknown and the pathogenic mechanism of SIMPLE mutations remains elusive. Here, we report that SIMPLE interacted and colocalized with endosomal sorting complex required for transport (ESCRT) components STAM1, Hrs, and TSG101 on early endosomes and functioned with the ESCRT machinery in the control of endosome-to-lysosome trafficking. Our analyses revealed that SIMPLE was required for efficient recruitment of ESCRT components to endosomal membranes and for regulating endosomal trafficking and signaling attenuation of ErbB receptors. We found that the ability of SIMPLE to regulate ErbB trafficking and signaling was impaired by CMT-linked SIMPLE mutations via a loss-of-function, dominant-negative mechanism, resulting in prolonged activation of ERK1/2 signaling. Our findings indicate a function of SIMPLE as a regulator of endosomal trafficking and provide evidence linking dysregulated endosomal trafficking to CMT pathogenesis.
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Affiliation(s)
- Samuel M Lee
- Department of Pharmacology and Center for Neurodegenerative Disease, Emory University School of Medicine, Atlanta, GA 30322, USA
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40
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Somandin C, Gerber D, Pereira JA, Horn M, Suter U. LITAF (SIMPLE) regulates Wallerian degeneration after injury but is not essential for peripheral nerve development and maintenance: implications for Charcot-Marie-Tooth disease. Glia 2012; 60:1518-28. [PMID: 22729949 DOI: 10.1002/glia.22371] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2012] [Accepted: 05/23/2012] [Indexed: 01/05/2023]
Abstract
Missense mutations affecting the LITAF gene (also known as SIMPLE) lead to the dominantly inherited peripheral neuropathy Charcot-Marie-Tooth disease type 1C (CMT1C). In this study, we sought to determine the requirement of Litaf function in peripheral nerves, the only known affected tissue in CMT1C. We reasoned that this knowledge is a prerequisite for a thorough understanding of the underlying disease mechanism with regard to potential contributions by Litaf loss of function. In addition, we anticipated to obtain valuable information about the basic function of the Litaf protein in peripheral nerves. To address these issues, we generated mice without Litaf expression using gene disruption in embryonic stem cells and analyzed Litaf-deficient peripheral nerves during development, in maintenance, and after injury. Our results show that Litaf function is not absolutely required for peripheral nerve development and maintenance. In injured nerves, however, we found that lack of Litaf led to increased numbers of macrophages during Wallerian degeneration, accelerated myelin destruction, and the emergence of more axonal sprouts. Consistent with these data, the migration of Litaf-deficient macrophages was increased upon chemokine stimulation. We conclude that loss of Litaf function is unlikely to be a major contributor to CMT1C, but modulating effects of macrophages need to be considered in the etiology of the disease.
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Affiliation(s)
- Christian Somandin
- Department of Biology, Institute of Molecular Health Sciences, Cell Biology, Swiss Federal Institute of Technology, ETH Zurich, CH-8093 Zurich, Switzerland
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Bucci C, Bakke O, Progida C. Charcot-Marie-Tooth disease and intracellular traffic. Prog Neurobiol 2012; 99:191-225. [PMID: 22465036 PMCID: PMC3514635 DOI: 10.1016/j.pneurobio.2012.03.003] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2011] [Revised: 12/23/2011] [Accepted: 03/13/2012] [Indexed: 12/23/2022]
Abstract
Mutations of genes whose primary function is the regulation of membrane traffic are increasingly being identified as the underlying causes of various important human disorders. Intriguingly, mutations in ubiquitously expressed membrane traffic genes often lead to cell type- or organ-specific disorders. This is particularly true for neuronal diseases, identifying the nervous system as the most sensitive tissue to alterations of membrane traffic. Charcot-Marie-Tooth (CMT) disease is one of the most common inherited peripheral neuropathies. It is also known as hereditary motor and sensory neuropathy (HMSN), which comprises a group of disorders specifically affecting peripheral nerves. This peripheral neuropathy, highly heterogeneous both clinically and genetically, is characterized by a slowly progressive degeneration of the muscle of the foot, lower leg, hand and forearm, accompanied by sensory loss in the toes, fingers and limbs. More than 30 genes have been identified as targets of mutations that cause CMT neuropathy. A number of these genes encode proteins directly or indirectly involved in the regulation of intracellular traffic. Indeed, the list of genes linked to CMT disease includes genes important for vesicle formation, phosphoinositide metabolism, lysosomal degradation, mitochondrial fission and fusion, and also genes encoding endosomal and cytoskeletal proteins. This review focuses on the link between intracellular transport and CMT disease, highlighting the molecular mechanisms that underlie the different forms of this peripheral neuropathy and discussing the pathophysiological impact of membrane transport genetic defects as well as possible future ways to counteract these defects.
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Affiliation(s)
- Cecilia Bucci
- Department of Biological and Environmental Sciences and Technologies (DiSTeBA), University of Salento, Via Provinciale Monteroni, 73100 Lecce, Italy.
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42
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Eaton HE, Metcalf J, Lacerda AF, Brunetti CR. Accumulation of endogenous LITAF in aggresomes. PLoS One 2012; 7:e30003. [PMID: 22276139 PMCID: PMC3261850 DOI: 10.1371/journal.pone.0030003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2011] [Accepted: 12/08/2011] [Indexed: 11/18/2022] Open
Abstract
LITAF is a 161 amino acid cellular protein which includes a proline rich N-terminus and a conserved C-terminal domain known as the simple-like domain. Mutations in LITAF have been identified in Charcot-Marie tooth disease, a disease characterized by protein aggregates. Cells transfected with cellular LITAF reveal that LITAF is localized to late endosomes/lysosomes. Here we investigated the intracellular localization of endogenous LITAF. We demonstrated that endogenous LITAF accumulates at a discrete cytoplasmic site in BGMK cells that we identify as the aggresome. To determine the domain within LITAF that is responsible for the localization of LITAF to aggresomes, we created a construct that contained the C-terminal simple-like domain of LITAF and found that this construct also localizes to aggresomes. These data suggest the simple-like domain is responsible for targeting endogenous LITAF to the aggresome.
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Affiliation(s)
- Heather E Eaton
- Department of Biology, Trent University, Peterborough, Ontario, Canada
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Timmerman V, Clowes VE, Reid E. Overlapping molecular pathological themes link Charcot-Marie-Tooth neuropathies and hereditary spastic paraplegias. Exp Neurol 2012; 246:14-25. [PMID: 22285450 DOI: 10.1016/j.expneurol.2012.01.010] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2011] [Revised: 12/29/2011] [Accepted: 01/10/2012] [Indexed: 10/14/2022]
Abstract
In this review we focus on Charcot-Marie-Tooth (CMT) neuropathies and hereditary spastic paraplegias (HSPs). Although these diseases differ in whether they primarily affect the peripheral or central nervous system, both are genetically determined, progressive, long axonopathies that affect motor and sensory pathways. This commonality suggests that there might be similarities in the molecular pathology underlying these conditions, and here we compare the molecular genetics and cellular pathology of the two groups.
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Affiliation(s)
- Vincent Timmerman
- Peripheral Neuropathy Group, Department of Molecular Genetics, VIB, Antwerpen, Belgium.
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Lee SM, Olzmann JA, Chin LS, Li L. Mutations associated with Charcot-Marie-Tooth disease cause SIMPLE protein mislocalization and degradation by the proteasome and aggresome-autophagy pathways. J Cell Sci 2011; 124:3319-31. [PMID: 21896645 DOI: 10.1242/jcs.087114] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Mutations in SIMPLE cause an autosomal dominant, demyelinating form of peripheral neuropathy termed Charcot-Marie-Tooth disease type 1C (CMT1C), but the pathogenic mechanisms of these mutations remain unknown. Here, we report that SIMPLE is an early endosomal membrane protein that is highly expressed in the peripheral nerves and Schwann cells. Our analysis has identified a transmembrane domain (TMD) embedded within the cysteine-rich (C-rich) region that anchors SIMPLE to the membrane, and suggests that SIMPLE is a post-translationally inserted, C-tail-anchored membrane protein. We found that CMT1C-linked pathogenic mutations are clustered within or around the TMD of SIMPLE and that these mutations cause mislocalization of SIMPLE from the early endosome membrane to the cytosol. The CMT1C-associated SIMPLE mutant proteins are unstable and prone to aggregation, and they are selectively degraded by both the proteasome and aggresome-autophagy pathways. Our findings suggest that SIMPLE mutations cause CMT1C peripheral neuropathy by a combination of loss-of-function and toxic gain-of-function mechanisms, and highlight the importance of both the proteasome and autophagy pathways in the clearance of CMT1C-associated mutant SIMPLE proteins.
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Affiliation(s)
- Samuel M Lee
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322, USA
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45
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He S, Tan G, Liu Q, Huang K, Ren J, Zhang X, Yu X, Huang P, An C. The LSD1-interacting protein GILP is a LITAF domain protein that negatively regulates hypersensitive cell death in Arabidopsis. PLoS One 2011; 6:e18750. [PMID: 21526181 PMCID: PMC3079718 DOI: 10.1371/journal.pone.0018750] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2011] [Accepted: 03/17/2011] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND Hypersensitive cell death, a form of avirulent pathogen-induced programmed cell death (PCD), is one of the most efficient plant innate immunity. However, its regulatory mechanism is poorly understood. AtLSD1 is an important negative regulator of PCD and only two proteins, AtbZIP10 and AtMC1, have been reported to interact with AtLSD1. METHODOLOGY/PRINCIPAL FINDINGS To identify a novel regulator of hypersensitive cell death, we investigate the possible role of plant LITAF domain protein GILP in hypersensitive cell death. Subcellular localization analysis showed that AtGILP is localized in the plasma membrane and its plasma membrane localization is dependent on its LITAF domain. Yeast two-hybrid and pull-down assays demonstrated that AtGILP interacts with AtLSD1. Pull-down assays showed that both the N-terminal and the C-terminal domains of AtGILP are sufficient for interactions with AtLSD1 and that the N-terminal domain of AtLSD1 is involved in the interaction with AtGILP. Real-time PCR analysis showed that AtGILP expression is up-regulated by the avirulent pathogen Pseudomonas syringae pv. tomato DC3000 avrRpt2 (Pst avrRpt2) and fumonisin B1 (FB1) that trigger PCD. Compared with wild-type plants, transgenic plants overexpressing AtGILP exhibited significantly less cell death when inoculated with Pst avrRpt2, indicating that AtGILP negatively regulates hypersensitive cell death. CONCLUSIONS/SIGNIFICANCE These results suggest that the LITAF domain protein AtGILP localizes in the plasma membrane, interacts with AtLSD1, and is involved in negatively regulating PCD. We propose that AtGILP functions as a membrane anchor, bringing other regulators of PCD, such as AtLSD1, to the plasma membrane. Human LITAF domain protein may be involved in the regulation of PCD, suggesting the evolutionarily conserved function of LITAF domain proteins in the regulation of PCD.
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Affiliation(s)
- Shanping He
- The State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing, China
| | - Guihong Tan
- The State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing, China
| | - Qian Liu
- The State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing, China
| | - Kuowei Huang
- The State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing, China
| | - Jiao Ren
- The State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing, China
| | - Xu Zhang
- The State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing, China
| | - Xiangchun Yu
- The State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing, China
| | - Ping Huang
- The State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing, China
| | - Chengcai An
- The State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing, China
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Eaton HE, Desrochers G, Drory SB, Metcalf J, Angers A, Brunetti CR. SIMPLE/LITAF expression induces the translocation of the ubiquitin ligase itch towards the lysosomal compartments. PLoS One 2011; 6:e16873. [PMID: 21326863 PMCID: PMC3033906 DOI: 10.1371/journal.pone.0016873] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2010] [Accepted: 01/17/2011] [Indexed: 01/05/2023] Open
Abstract
LITAF is a small cellular protein with an unknown function. The C-terminus of LITAF contains a highly conserved domain termed the SIMPLE-like domain (SLD), while the N-terminus contains two PPXY motifs that mediate protein-protein interactions with WW-domain containing proteins. LITAF also harbors two endosome/lysosome targeting sequences at its C-terminus, but there has been conflicting reports regarding its intracellular localization. Here, we demonstrate that LITAF is localized to the late endosome/lysosomal compartment in a variety of cell lines. We also show that Itch, a WW-domain containing protein, and LITAF strongly interact and that this interaction depends on the two PPXY motifs in the N-terminus of LITAF. Interestingly, co-expression of LITAF with Itch induces major changes in Itch intracellular localization, bringing Itch from the trans-Golgi network to lysosomes. We show that this re-localization is dependent upon the interaction with the PPXY sequences of LITAF, since disruption of these binding motifs completely abrogates Itch re-localization.
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Affiliation(s)
| | - Guillaume Desrochers
- Département de Sciences Biologiques, Université de Montréal, Station ‘Centre-Ville’, Montréal, Canada
| | - Samuel B. Drory
- Département de Sciences Biologiques, Université de Montréal, Station ‘Centre-Ville’, Montréal, Canada
| | - Julie Metcalf
- Department of Biology, Trent University, Peterborough, Canada
| | - Annie Angers
- Département de Sciences Biologiques, Université de Montréal, Station ‘Centre-Ville’, Montréal, Canada
| | - Craig R. Brunetti
- Department of Biology, Trent University, Peterborough, Canada
- * E-mail:
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Guernsey DL, Jiang H, Bedard K, Evans SC, Ferguson M, Matsuoka M, Macgillivray C, Nightingale M, Perry S, Rideout AL, Orr A, Ludman M, Skidmore DL, Benstead T, Samuels ME. Mutation in the gene encoding ubiquitin ligase LRSAM1 in patients with Charcot-Marie-Tooth disease. PLoS Genet 2010; 6. [PMID: 20865121 PMCID: PMC2928813 DOI: 10.1371/journal.pgen.1001081] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2010] [Accepted: 07/22/2010] [Indexed: 01/30/2023] Open
Abstract
Charcot-Marie-Tooth disease (CMT) represents a family of related sensorimotor neuropathies. We studied a large family from a rural eastern Canadian community, with multiple individuals suffering from a condition clinically most similar to autosomal recessive axonal CMT, or AR-CMT2. Homozygosity mapping with high-density SNP genotyping of six affected individuals from the family excluded 23 known genes for various subtypes of CMT and instead identified a single homozygous region on chromosome 9, at 122,423,730–129,841,977 Mbp, shared identical by state in all six affected individuals. A homozygous pathogenic variant was identified in the gene encoding leucine rich repeat and sterile alpha motif 1 (LRSAM1) by direct DNA sequencing of genes within the region in affected DNA samples. The single nucleotide change mutates an intronic consensus acceptor splicing site from AG to AA. Direct analysis of RNA from patient blood demonstrated aberrant splicing of the affected exon, causing an obligatory frameshift and premature truncation of the protein. Western blotting of immortalized cells from a homozygous patient showed complete absence of detectable protein, consistent with the splice site defect. LRSAM1 plays a role in membrane vesicle fusion during viral maturation and for proper adhesion of neuronal cells in culture. Other ubiquitin ligases play documented roles in neurodegenerative diseases. LRSAM1 is a strong candidate for the causal gene for the genetic disorder in our kindred. Sensory motor neuropathies are diseases of the peripheral nervous system, involving primarily the nerves which control our muscles. These can result from either genetic or non-genetic causes, with genetic causes usually referred to as Charcot-Marie-Tooth (CMT) disease after the three clinicians who first described the key diagnostic markers. CMT patients lose muscle function, mainly in their arms and legs, with increasing severity during their lives. There are almost two dozen known genes that can mutate to cause CMT, and these fall into a wide variety of biochemical cellular pathways. We identified a group of patients with CMT from a small rural community, with good reason to suspect a genetic basis for their disease. Using high-throughput mapping and DNA sequencing technologies developed as part of the Human Genome Project, we were able to find the likely mutated gene, which was not any of the previously known CMT genes. Based on its sequence, the gene, called LRSAM1, probably plays a role in the correct metabolism of other proteins in the cell. Among the known CMT genes, some are also involved in protein metabolism, suggesting that this is a generally important pathway in the neurons that control muscle activity.
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Affiliation(s)
- Duane L. Guernsey
- Department of Pathology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Haiyan Jiang
- Department of Pathology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Karen Bedard
- Department of Pathology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Susan C. Evans
- Department of Pathology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Meghan Ferguson
- Maritime Medical Genetics Service, Izaak Walton Killam Health Centre, Halifax, Nova Scotia, Canada
| | - Makoto Matsuoka
- Department of Pathology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Christine Macgillivray
- Department of Pathology, Dalhousie University, Halifax, Nova Scotia, Canada
- Department of Ophthalmology and Visual Sciences, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Mathew Nightingale
- Department of Pathology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Scott Perry
- Department of Pathology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Andrea L. Rideout
- Maritime Medical Genetics Service, Izaak Walton Killam Health Centre, Halifax, Nova Scotia, Canada
| | - Andrew Orr
- Department of Ophthalmology and Visual Sciences, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Mark Ludman
- Maritime Medical Genetics Service, Izaak Walton Killam Health Centre, Halifax, Nova Scotia, Canada
- Department of Pediatrics, Division of Medical Genetics, Izaak Walton Killam Health Centre and Dalhousie University, Halifax, Nova Scotia, Canada
| | - David L. Skidmore
- Maritime Medical Genetics Service, Izaak Walton Killam Health Centre, Halifax, Nova Scotia, Canada
- Department of Pediatrics, Division of Medical Genetics, Izaak Walton Killam Health Centre and Dalhousie University, Halifax, Nova Scotia, Canada
| | - Timothy Benstead
- Department of Medicine, Division of Neurology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Mark E. Samuels
- Department of Pathology, Dalhousie University, Halifax, Nova Scotia, Canada
- Centre de Recherche de l'Hôpital Ste-Justine, Université de Montréal, Montréal, Quebec, Canada
- * E-mail:
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Abstract
Components of the ESCRT (endosomal sorting complex required for transport) machinery mediate endosomal sorting of ubiquitinated membrane proteins. They are key regulators of biological processes important for cell growth and survival, such as growth-factor-mediated signalling and cytokinesis. In addition, enveloped viruses, such as HIV-1, hijack and utilize the ESCRTs for budding during virus release and infection. Obviously, the ESCRT-facilitated pathways require tight regulation, which is partly mediated by a group of interacting proteins, for which our knowledge is growing. In this review we discuss the different ESCRT-modulating proteins and how they influence ESCRT-dependent processes, for example, by acting as positive or negative regulators or by providing temporal and spatial control. A number of the interactors influence the classical ESCRT-mediated process of endosomal cargo sorting, for example, by modulating the interaction between ubiquitinated cargo and the ESCRTs. Certain accessory proteins have been implicated in regulating the activity or steady-state expression levels of the ESCRT components, whereas other interactors control the cellular localization of the ESCRTs, for example, by inducing shuttling between cytosol and nucleus or endosomes. In conclusion, the discovery of novel interactors has and will extend our knowledge of the biological roles of ESCRTs.
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Shi S, Notenboom S, Dumont ME, Ballatori N. Identification of human gene products containing Pro-Pro-x-Tyr (PY) motifs that enhance glutathione and endocytotic marker uptake in yeast. Cell Physiol Biochem 2010; 25:293-306. [PMID: 20110690 DOI: 10.1159/000276570] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/19/2009] [Indexed: 11/19/2022] Open
Abstract
In an attempt to identify genes involved in glutathione (GSH) transport, a human mammary gland cDNA library was screened for clones capable of complementing a defect in GSH uptake in yeast cells that lack Hgt1p, the primary yeast GSH uptake transporter. Five genes capable of rescuing growth on sulfur-deficient GSH-containing medium were identified: prostate transmembrane protein, androgen induced 1 (PMEPA1); lysosomal-associated protein transmembrane 4 alpha (LAPTM4alpha); solute carrier family 25, member 1 (SLC25A1); lipopolysaccharide-induced TNF factor (LITAF); and cysteine/tyrosine-rich-1 (CYYR1). All of these genes encode small integral membrane proteins of unknown function, although none appear to encode prototypical GSH transporters. Nevertheless, they all increased both intracellular glutathione levels and [(3)H]GSH uptake rates. [(3)H]GSH uptake was uniformly inhibited by high concentrations of unlabeled GSH, GSSG, and ophthalmic acid. Interestingly, each protein is predicted to contain Pro-Pro-x-Tyr (PY) motifs, which are thought to be important for regulating protein cell surface expression. Uptake of the endocytotic markers lucifer yellow and FM4-64 was also enhanced by each of the five genes. Mutations of the PY motifs in LITAF largely abolished all of its effects. In summary, although the results do not reveal novel GSH transporters, they identify five PY-containing human gene products that may influence plasma membrane transport activity.
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Affiliation(s)
- Shujie Shi
- Department of Environmental Medicine, University of Rochester School of Medicine, Rochester, NY, USA
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Aoh QL, Castle AM, Hubbard CH, Katsumata O, Castle JD. SCAMP3 negatively regulates epidermal growth factor receptor degradation and promotes receptor recycling. Mol Biol Cell 2009; 20:1816-32. [PMID: 19158374 DOI: 10.1091/mbc.e08-09-0894] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The epidermal growth factor receptor (EGFR) is targeted for lysosomal degradation by ubiquitin-mediated interactions with the ESCRTs (endosomal-sorting complexes required for transport) in multivesicular bodies (MVBs). We show that secretory carrier membrane protein, SCAMP3, localizes in part to early endosomes and negatively regulates EGFR degradation through processes that involve its ubiquitylation and interactions with ESCRTs. SCAMP3 is multimonoubiquitylated and is able to associate with Nedd4 HECT ubiquitin ligases and the ESCRT-I subunit Tsg101 via its PY and PSAP motifs, respectively. SCAMP3 also associates with the ESCRT-0 subunit Hrs. Depletion of SCAMP3 in HeLa cells by inhibitory RNA accelerated degradation of EGFR and EGF while inhibiting recycling. Conversely, overexpression enhanced EGFR recycling unless ubiquitylatable lysines, PY or PSAP motifs in SCAMP3 were mutated. Notably, dual depletions of SCAMP3 and ESCRT subunits suggest that SCAMP3 has a distinct function in parallel with the ESCRTs that regulates receptor degradation. This function may affect trafficking of receptors from prelysosomal compartments as SCAMP3 depletion appeared to sustain the incidence of EGFR-containing MVBs detected by immunoelectron microscopy. Together, our results suggest that SCAMP3, its modification with ubiquitin, and its interactions with ESCRTs coordinately regulate endosomal pathways and affect the efficiency of receptor down-regulation.
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Affiliation(s)
- Quyen L Aoh
- Department of Cell Biology, University of Virginia, Charlottesville, VA 22908, USA
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