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Ayagama T, Charles PD, Bose SJ, Boland B, Priestman DA, Aston D, Berridge G, Fischer R, Cribbs AP, Song Q, Mirams GR, Amponsah K, Heather L, Galione A, Herring N, Kramer H, Capel RA, Platt FM, Schotten U, Verheule S, Burton RA. Compartmentalization proteomics revealed endolysosomal protein network changes in a goat model of atrial fibrillation. iScience 2024; 27:109609. [PMID: 38827406 PMCID: PMC11141153 DOI: 10.1016/j.isci.2024.109609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 02/07/2024] [Accepted: 03/25/2024] [Indexed: 06/04/2024] Open
Abstract
Endolysosomes (EL) are known for their role in regulating both intracellular trafficking and proteostasis. EL facilitate the elimination of damaged membranes, protein aggregates, membranous organelles and play an important role in calcium signaling. The specific role of EL in cardiac atrial fibrillation (AF) is not well understood. We isolated atrial EL organelles from AF goat biopsies and conducted a comprehensive integrated omics analysis to study the EL-specific proteins and pathways. We also performed electron tomography, protein and enzyme assays on these biopsies. Our results revealed the upregulation of the AMPK pathway and the expression of EL-specific proteins that were not found in whole tissue lysates, including GAA, DYNLRB1, CLTB, SIRT3, CCT2, and muscle-specific HSPB2. We also observed structural anomalies, such as autophagic-vacuole formation, irregularly shaped mitochondria, and glycogen deposition. Our results provide molecular information suggesting EL play a role in AF disease process over extended time frames.
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Affiliation(s)
- Thamali Ayagama
- Department of Pharmacology, University of Oxford, Oxford, UK
| | | | - Samuel J. Bose
- Department of Pharmacology, University of Oxford, Oxford, UK
| | - Barry Boland
- Department of Pharmacology and Therapeutics, University College Cork, Cork, Ireland
| | | | - Daniel Aston
- Department of Anaesthesia and Critical Care, Royal Papworth Hospital NHS Foundation Trust, Papworth Road, Cambridge CB2 0AY, UK
| | | | - Roman Fischer
- Target Discovery Institute, University of Oxford, Oxford, UK
| | - Adam P. Cribbs
- Nuffield Department of Orthopaedics Rheumatology and Musculoskeletal Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, Botnar Research Centre, University of Oxford, Headington OX3 7LD, UK
| | - Qianqian Song
- Department of Pharmacology, University of Oxford, Oxford, UK
| | - Gary R. Mirams
- Centre for Mathematical Medicine & Biology, Mathematical Sciences, University of Nottingham, Nottingham NG7 2RD, UK
| | - Kwabena Amponsah
- Centre for Mathematical Medicine & Biology, Mathematical Sciences, University of Nottingham, Nottingham NG7 2RD, UK
| | - Lisa Heather
- Department of Physiology, Anatomy and Genetics, , University of Oxford, South Park Road, Oxford OX1 3PT, UK
| | - Antony Galione
- Department of Pharmacology, University of Oxford, Oxford, UK
| | - Neil Herring
- Department of Physiology, Anatomy and Genetics, , University of Oxford, South Park Road, Oxford OX1 3PT, UK
| | - Holger Kramer
- Mass spectrometry Facility, The MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | | | | | - Ulrich Schotten
- Departments of Physiology and Cardiology, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, the Netherlands
| | - Sander Verheule
- Departments of Physiology and Cardiology, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, the Netherlands
| | - Rebecca A.B. Burton
- Department of Pharmacology, University of Oxford, Oxford, UK
- University of Liverpool, Department of Pharmacology and Therapeutics, Institute of Systems, Molecular and Integrative Biology, Liverpool, UK
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Ansari I, Singh AK, Kapoor A, Mukhopadhyay A. Unconventional role of Rab4 in the secretory pathway in Leishmania. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2024; 1871:119687. [PMID: 38342312 DOI: 10.1016/j.bbamcr.2024.119687] [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: 07/27/2023] [Revised: 01/27/2024] [Accepted: 01/31/2024] [Indexed: 02/13/2024]
Abstract
Leishmania donovani is an auxotroph for heme. Parasite acquires heme by clathrin-mediated endocytosis of hemoglobin by specific receptor. However, the regulation of receptor recycling pathway is not known in Leishmania. Here, we have cloned, expressed and characterized the Rab4 homologue from L. donovani. We have found that LdRab4 localizes in both early endosomes and Golgi in L. donovani. To understand the role of LdRab4 in L. donovani, we have generated transgenic parasites overexpressing GFP-LdRab4:WT, GFP-LdRab4:Q67L, and GFP-LdRab4:S22N. Our results have shown that overexpression of GFP-LdRab4:Q67L or GFP-LdRab4:S22N does not alter the cell surface localization of hemoglobin receptor in L. donovani. Surprisingly, we have found that overexpression of GFP-LdRab4:S22N significantly blocks the transport of Ldgp63 to the cell surface whereas the trafficking of Ldgp63 is induced to the cell surface in GFP-LdRab4:WT and GFP-LdRab4:Q67L overexpressing parasites. Consequently, we have found significant inhibition of gp63 secretion by GFP-LdRab4:S22N overexpressing parasites whereas secretion of Ldgp63 is enhanced in GFP-LdRab4:WT and GFP-LdRab4:Q67L overexpressing parasites in comparison to untransfected control parasites. Moreover, we have found that survival of transgenic parasites overexpressing GFP-LdRab4:S22N is severely compromised in macrophages in comparison to GFP-LdRab4:WT and GFP-LdRab4:Q67L expressing parasites. These results demonstrated that LdRab4 unconventionally regulates the secretory pathway in L. donovani.
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Affiliation(s)
- Irshad Ansari
- Kusuma School of Biological Sciences, Indian Institute of Technology, Haus Khas, New Delhi 110016, India
| | - Amir Kumar Singh
- Kusuma School of Biological Sciences, Indian Institute of Technology, Haus Khas, New Delhi 110016, India
| | - Anjali Kapoor
- Kusuma School of Biological Sciences, Indian Institute of Technology, Haus Khas, New Delhi 110016, India
| | - Amitabha Mukhopadhyay
- Kusuma School of Biological Sciences, Indian Institute of Technology, Haus Khas, New Delhi 110016, India.
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Yamaguchi F, Sakane H, Akasaki K. Comparative study of the steady-state subcellular distribution of lysosome-associated membrane glycoprotein-2 (LAMP-2) isoforms with GYXXΦ-type tyrosine-based motifs that interact differently with four adaptor protein (AP) complexes. J Biochem 2024; 175:275-287. [PMID: 37983719 DOI: 10.1093/jb/mvad096] [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: 08/08/2023] [Revised: 10/23/2023] [Accepted: 11/06/2023] [Indexed: 11/22/2023] Open
Abstract
Lysosome-associated membrane protein-1 and -2 (LAMP-1 and LAMP-2, respectively) are type I transmembrane proteins. LAMP-2 comprises three splice isoforms (LAMP-2A, -B and-C) with different cytoplasmic tails (CTs). These three CTs possess different tyrosine-based motifs (GYXXΦ, where Φ is a bulky hydrophobic amino acid) at their C-termini. Interactions between tyrosine-based motifs and μ-subunits of four tetrameric adaptor protein (AP) complexes are necessary for their vesicular transport to lysosomes. Little is known about how the interaction strengths of these tyrosine motifs with μ-subunits affect the localization of isoforms to lysosomes. The interactions were first investigated using a yeast two-hybrid system to address this question. LAMP-2A-CT interacted with all four μ-subunits (μ1, μ2, μ3A and μ4 of AP-1, AP-2, AP-3 and AP-4, respectively). The interaction with μ3A was more robust than that with other μ-subunits. LAMP-2B-CT interacted exclusively and moderately with μ3A. LAMP-2C-CT did not detectably interact with any of the four μ-subunits. Immunofluorescence microscopy showed that all isoforms were localized in late endosomes and lysosomes. LAMP-2C was present in the plasma membrane and early endosomes; however, LAMP-2A and -2B were barely detectable in these organelles. In cell fractionation, LAMP-2A was the most abundant in the dense lysosomes, whereas LAMP-2C was significantly present in the low-density fraction containing the plasma membrane and early endosomes, in addition to the dense lysosomes. LAMP-2B considerably existed in the low-density late endosomal fraction. These data strongly suggest that the LAMP-2 isoforms are distributed differently in endocytic organelles depending on their interaction strengths with AP-3.
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Affiliation(s)
- Fumiaki Yamaguchi
- Faculty of Pharmacy and Pharmaceutical Sciences, Fukuyama University, Fukuyama, Hiroshima 729-0292, Japan
| | - Hiroshi Sakane
- Faculty of Pharmacy and Pharmaceutical Sciences, Fukuyama University, Fukuyama, Hiroshima 729-0292, Japan
| | - Kenji Akasaki
- Faculty of Pharmacy and Pharmaceutical Sciences, Fukuyama University, Fukuyama, Hiroshima 729-0292, Japan
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Krishnan V, Nath S, Nair P, Das B. Mycobacterium tuberculosis and its clever approaches to escape the deadly macrophage. World J Microbiol Biotechnol 2023; 39:300. [PMID: 37667129 DOI: 10.1007/s11274-023-03735-9] [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: 06/21/2023] [Accepted: 08/19/2023] [Indexed: 09/06/2023]
Abstract
Mycobacterium tuberculosis (Mt.b), a deadly disease causer, is a facultative parasite. This microorganism has developed several methods to defend itself, once internalized within specialised vacuoles in the macrophages. A wide array of receptors like the complement receptor mannose receptors, scavenger receptor assists the entry of the microbe within the phagocytic macrophages. However, Mt.b is clever enough to protect itself from the hostile environment of the macrophage thereby prevailing within it. The microbe can efficiently inhibit processes like phagosome-lysosome fusion, acidification of phagosomes, release of proinflammatory cytokines and stop crucial events like apoptosis. Additionally, it also adopts resistance to killing by reactive oxygen intermediates and reactive nitrogen intermediates. There are multiple genes both in host and the pathogen which are involved in this successful survival of Mt.b. The regulation of phagolysosome fusion is mediated by proteins such as Coronin, TlyA, SapM, PnkG, EsxH. The microbe has certain mechanisms to even acquire iron from the host cell, to withstand iron deprivation as a mode of host's defence mechanism. This review focuses on the various defensive adaptations acquired by Mt.b for fighting against the deprived conditions existing within the macrophages and their capability of proliferating successfully within it, thereby resulting in a diseased condition.
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Affiliation(s)
- Vinaya Krishnan
- Department of Biotechnology, Mount Carmel College Autonomous, Bengaluru, 560052, India
| | | | - Preetha Nair
- Department of Biotechnology, Mount Carmel College Autonomous, Bengaluru, 560052, India
| | - Bannhi Das
- Department of Biotechnology, Mount Carmel College Autonomous, Bengaluru, 560052, India.
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Xiao D, Yao J, Gao X, Zhu KY. Clathrin-dependent endocytosis plays a critical role in larval and pupal development, and female oocyte production in the red flour beetle (Tribolium castaneum). PEST MANAGEMENT SCIENCE 2023; 79:1731-1742. [PMID: 36617731 DOI: 10.1002/ps.7348] [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: 07/20/2022] [Revised: 10/14/2022] [Accepted: 01/09/2023] [Indexed: 06/17/2023]
Abstract
BACKGROUND Clathrin-dependent endocytosis is a vesicular transport process by which cells take macromolecules from the extracellular space to the intracellular space. It plays important roles in various cellular functions, but its biological significance in insect development and reproduction has not been well studied. RESULTS We characterized and functionally analyzed four major clathrin-dependent endocytic pathway genes (TcChc, TcAP50, TcVhaSFD, TcRab7) in Tribolium castaneum. RNA interference (RNAi) by injecting double-stranded RNA (dsRNA) targeting each gene at three doses (50, 100, or 200 ng per insect) in 20-day-old larvae led to 100% larval mortality. When the expressions of TcChc, TcVhaSFD, and TcRab7 were suppressed by injecting their respective dsRNAs at each dose in 1-day-old pupae, the adults that emerged from the dsRNA-injected pupae were deformed, with the absence of wing development. The deformed adults died within 2 days after eclosion. When the expression of TcAP50 was suppressed by injecting its dsRNA into 1-day-old pupae, although no apparent deformed adults were observed, all the adults died within 35 days after eclosion. In addition, when the expressions of TcChc and TcVhaSFD were suppressed by injecting their respective dsRNAs at a reduced dose (10 ng per insect) in 5-day-old pupae, the ovarian development and oocyte production in the resultant females were completely inhibited. CONCLUSION Our results indicate that clathrin-dependent endocytosis is essential for insect development and reproduction. The results from this study can help researchers identify potential molecular targets for developing novel strategies for insect pest management. © 2023 Society of Chemical Industry.
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Affiliation(s)
- Da Xiao
- Institute of Plant Protection, Beijing Academy of Agriculture and Forestry Sciences, Beijing, People's Republic of China
- Department of Entomology, China Agricultural University, Beijing, People's Republic of China
- Department of Entomology, 123 Waters Hall, Kansas State University, Manhattan, Kansas, USA
| | - Jianxiu Yao
- Department of Entomology, 123 Waters Hall, Kansas State University, Manhattan, Kansas, USA
| | - Xiwu Gao
- Department of Entomology, China Agricultural University, Beijing, People's Republic of China
| | - Kun Yan Zhu
- Department of Entomology, 123 Waters Hall, Kansas State University, Manhattan, Kansas, USA
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Targeting VPS41 induces methuosis and inhibits autophagy in cancer cells. Cell Chem Biol 2023; 30:130-143.e5. [PMID: 36708709 DOI: 10.1016/j.chembiol.2023.01.002] [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: 04/16/2022] [Revised: 11/09/2022] [Accepted: 01/09/2023] [Indexed: 01/28/2023]
Abstract
The homotypic fusion and vacuole protein sorting (HOPS) complex mediates membrane trafficking involved in endocytosis, autophagy, lysosome biogenesis, and phagocytosis. Defects in HOPS subunits are associated with various forms of cancer, but their potential as drug targets has rarely been examined. Here, we identified vacuolar protein sorting-associated protein 41 homolog (VPS41), a subunit of the HOPS complex, as a target of methyl 2,4-dihydroxy-3-(3-methyl-2-butenyl)-6-phenethylbenzoate (DMBP), a natural small molecule with preferable anticancer activity. DMBP induced methuosis and inhibited autophagic flux in cancer cells by inhibiting the function of VPS41, leading to the restrained fusion of late endosomes and autophagosomes with lysosomes. Moreover, DMBP effectively inhibited metastasis in a mouse metastatic melanoma model. Collectively, the current work revealed that targeting VPS41 would provide a valuable method of inhibiting cancer proliferation through methuosis.
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7
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A CRISPR-Cas9 screen reveals a role for WD repeat-containing protein 81 (WDR81) in the entry of late penetrating viruses. PLoS Pathog 2022; 18:e1010398. [PMID: 35320319 PMCID: PMC8942271 DOI: 10.1371/journal.ppat.1010398] [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: 09/30/2021] [Accepted: 02/25/2022] [Indexed: 12/02/2022] Open
Abstract
Successful initiation of infection by many different viruses requires their uptake into the endosomal compartment. While some viruses exit this compartment early, others must reach the degradative, acidic environment of the late endosome. Mammalian orthoreovirus (reovirus) is one such late penetrating virus. To identify host factors that are important for reovirus infection, we performed a CRISPR-Cas9 knockout (KO) screen that targets over 20,000 genes in fibroblasts derived from the embryos of C57/BL6 mice. We identified seven genes (WDR81, WDR91, RAB7, CCZ1, CTSL, GNPTAB, and SLC35A1) that were required for the induction of cell death by reovirus. Notably, CRISPR-mediated KO of WD repeat-containing protein 81 (WDR81) rendered cells resistant to reovirus infection. Susceptibility to reovirus infection was restored by complementing KO cells with human WDR81. Although the absence of WDR81 did not affect viral attachment efficiency or uptake into the endosomal compartments for initial disassembly, it reduced viral gene expression and diminished infectious virus production. Consistent with the role of WDR81 in impacting the maturation of endosomes, WDR81-deficiency led to the accumulation of reovirus particles in dead-end compartments. Though WDR81 was dispensable for infection by VSV (vesicular stomatitis virus), which exits the endosomal system at an early stage, it was required for VSV-EBO GP (VSV that expresses the Ebolavirus glycoprotein), which must reach the late endosome to initiate infection. These results reveal a previously unappreciated role for WDR81 in promoting the replication of viruses that transit through late endosomes. Viruses are obligate intracellular parasites that require the contributions of numerous host factors to complete the viral life cycle. Thus, the host-pathogen interaction can regulate cell death signaling and virus entry, replication, assembly, and egress. Functional genetic screens are useful tools to identify host factors that are important for establishing infection. Such information can also be used to understand cell biology. Notably, genome-scale CRISPR-Cas9 knockout screens are robust due to their specificity and the loss of host gene expression. Mammalian orthoreovirus (reovirus) is a tractable model system to investigate the pathogenesis of neurotropic and cardiotropic viruses. Using a CRISPR-Cas9 screen, we identified WD repeat-containing protein 81 (WDR81) as a host factor required for efficient reovirus infection of murine cells. Ablation of WDR81 blocked a late step in the viral entry pathway. Further, our work indicates that WDR81 is required for the entry of vesicular stomatitis virus that expresses the Ebolavirus glycoprotein.
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Blandin CE, Gravez BJ, Hatem SN, Balse E. Remodeling of Ion Channel Trafficking and Cardiac Arrhythmias. Cells 2021; 10:cells10092417. [PMID: 34572065 PMCID: PMC8468138 DOI: 10.3390/cells10092417] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 09/08/2021] [Accepted: 09/11/2021] [Indexed: 01/08/2023] Open
Abstract
Both inherited and acquired cardiac arrhythmias are often associated with the abnormal functional expression of ion channels at the cellular level. The complex machinery that continuously traffics, anchors, organizes, and recycles ion channels at the plasma membrane of a cardiomyocyte appears to be a major source of channel dysfunction during cardiac arrhythmias. This has been well established with the discovery of mutations in the genes encoding several ion channels and ion channel partners during inherited cardiac arrhythmias. Fibrosis, altered myocyte contacts, and post-transcriptional protein changes are common factors that disorganize normal channel trafficking during acquired cardiac arrhythmias. Channel availability, described notably for hERG and KV1.5 channels, could be another potent arrhythmogenic mechanism. From this molecular knowledge on cardiac arrhythmias will emerge novel antiarrhythmic strategies.
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Affiliation(s)
- Camille E. Blandin
- INSERM, Unité de Recherche sur les Maladies Cardiovasculaires, le Métabolisme et la Nutrition—UNITE 1166, Sorbonne Université, EQUIPE 3, F-75013 Paris, France; (C.E.B.); (B.J.G.); (S.N.H.)
| | - Basile J. Gravez
- INSERM, Unité de Recherche sur les Maladies Cardiovasculaires, le Métabolisme et la Nutrition—UNITE 1166, Sorbonne Université, EQUIPE 3, F-75013 Paris, France; (C.E.B.); (B.J.G.); (S.N.H.)
| | - Stéphane N. Hatem
- INSERM, Unité de Recherche sur les Maladies Cardiovasculaires, le Métabolisme et la Nutrition—UNITE 1166, Sorbonne Université, EQUIPE 3, F-75013 Paris, France; (C.E.B.); (B.J.G.); (S.N.H.)
- ICAN—Institute of Cardiometabolism and Nutrition, Institute of Cardiology, Pitié-Salpêtrière Hospital, Sorbonne University, F-75013 Paris, France
| | - Elise Balse
- INSERM, Unité de Recherche sur les Maladies Cardiovasculaires, le Métabolisme et la Nutrition—UNITE 1166, Sorbonne Université, EQUIPE 3, F-75013 Paris, France; (C.E.B.); (B.J.G.); (S.N.H.)
- Correspondence:
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Anes E, Azevedo-Pereira JM, Pires D. Cathepsins and Their Endogenous Inhibitors in Host Defense During Mycobacterium tuberculosis and HIV Infection. Front Immunol 2021; 12:726984. [PMID: 34421929 PMCID: PMC8371317 DOI: 10.3389/fimmu.2021.726984] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 07/22/2021] [Indexed: 01/15/2023] Open
Abstract
The moment a very old bacterial pathogen met a young virus from the 80's defined the beginning of a tragic syndemic for humanity. Such is the case for the causative agent of tuberculosis and the human immunodeficiency virus (HIV). Syndemic is by definition a convergence of more than one disease resulting in magnification of their burden. Both pathogens work synergistically contributing to speed up the replication of each other. Mycobacterium tuberculosis (Mtb) and HIV infections are in the 21st century among the leaders of morbidity and mortality of humankind. There is an urgent need for development of new approaches for prevention, better diagnosis, and new therapies for both infections. Moreover, these approaches should consider Mtb and HIV as a co-infection, rather than just as separate problems, to prevent further aggravation of the HIV-TB syndemic. Both pathogens manipulate the host immune responses to establish chronic infections in intracellular niches of their host cells. This includes manipulation of host relevant antimicrobial proteases such as cathepsins or their endogenous inhibitors. Here we discuss recent understanding on how Mtb and HIV interact with cathepsins and their inhibitors in their multifactorial functions during the pathogenesis of both infections. Particularly we will address the role on pathogen transmission, during establishment of intracellular chronic niches and in granuloma clinical outcome and tuberculosis diagnosis. This area of research will open new avenues for the design of innovative therapies and diagnostic interventions so urgently needed to fight this threat to humanity.
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Affiliation(s)
- Elsa Anes
- Host-Pathogen Interactions Unit, Research Institute for Medicines, iMed-ULisboa, Faculty of Pharmacy, Universidade de Lisboa, Lisboa, Portugal
| | - José Miguel Azevedo-Pereira
- Host-Pathogen Interactions Unit, Research Institute for Medicines, iMed-ULisboa, Faculty of Pharmacy, Universidade de Lisboa, Lisboa, Portugal
| | - David Pires
- Host-Pathogen Interactions Unit, Research Institute for Medicines, iMed-ULisboa, Faculty of Pharmacy, Universidade de Lisboa, Lisboa, Portugal
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Sachdeva K, Sundaramurthy V. The Interplay of Host Lysosomes and Intracellular Pathogens. Front Cell Infect Microbiol 2020; 10:595502. [PMID: 33330138 PMCID: PMC7714789 DOI: 10.3389/fcimb.2020.595502] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Accepted: 10/22/2020] [Indexed: 12/20/2022] Open
Abstract
Lysosomes are an integral part of the intracellular defense system against microbes. Lysosomal homeostasis in the host is adaptable and responds to conditions such as infection or nutritional deprivation. Pathogens such as Mycobacterium tuberculosis (Mtb) and Salmonella avoid lysosomal targeting by actively manipulating the host vesicular trafficking and reside in a vacuole altered from the default lysosomal trafficking. In this review, the mechanisms by which the respective pathogen containing vacuoles (PCVs) intersect with lysosomal trafficking pathways and maintain their distinctness are discussed. Despite such active inhibition of lysosomal targeting, emerging literature shows that different pathogens or pathogen derived products exhibit a global influence on the host lysosomal system. Pathogen mediated lysosomal enrichment promotes the trafficking of a sub-set of pathogens to lysosomes, indicating heterogeneity in the host-pathogen encounter. This review integrates recent advancements on the global lysosomal alterations upon infections and the host protective role of the lysosomes against these pathogens. The review also briefly discusses the heterogeneity in the lysosomal targeting of these pathogens and the possible mechanisms and consequences.
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Lysosomal Hydrolase Cathepsin D Non-proteolytically Modulates Dendritic Morphology in Drosophila. Neurosci Bull 2020; 36:1147-1157. [PMID: 32170568 PMCID: PMC7532236 DOI: 10.1007/s12264-020-00479-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Accepted: 12/19/2019] [Indexed: 01/09/2023] Open
Abstract
The main lysosomal protease cathepsin D (cathD) is essential for maintaining tissue homeostasis via its degradative function, and its loss leads to ceroid accumulation in the mammalian nervous system, which results in progressive neurodegeneration. Increasing evidence implies non-proteolytic roles of cathD in regulating various biological processes such as apoptosis, cell proliferation, and migration. Along these lines, we here showed that cathD is required for modulating dendritic architecture in the nervous system independent of its traditional degradative function. Upon cathD depletion, class I and class III arborization (da) neurons in Drosophila larvae exhibited aberrant dendritic morphology, including over-branching, aberrant turning, and elongation defects. Re-introduction of wild-type cathD or its proteolytically-inactive mutant dramatically abolished these morphological defects. Moreover, cathD knockdown also led to dendritic defects in the adult mushroom bodies, suggesting that cathD-mediated processes are required in both the peripheral and central nervous systems. Taken together, our results demonstrate a critical role of cathD in shaping dendritic architecture independent of its proteolytic function.
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Interfering with endolysosomal trafficking enhances release of bioactive exosomes. NANOMEDICINE-NANOTECHNOLOGY BIOLOGY AND MEDICINE 2019; 20:102014. [DOI: 10.1016/j.nano.2019.102014] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 04/15/2019] [Accepted: 05/03/2019] [Indexed: 01/08/2023]
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13
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Vorberg IM. All the Same? The Secret Life of Prion Strains within Their Target Cells. Viruses 2019; 11:v11040334. [PMID: 30970585 DOI: 10.3390/v11040334] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 04/02/2019] [Accepted: 04/05/2019] [Indexed: 01/23/2023] Open
Abstract
Prions are infectious β-sheet-rich protein aggregates composed of misfolded prion protein (PrPSc) that do not possess coding nucleic acid. Prions replicate by recruiting and converting normal cellular PrPC into infectious isoforms. In the same host species, prion strains target distinct brain regions and cause different disease phenotypes. Prion strains are associated with biophysically distinct PrPSc conformers, suggesting that strain properties are enciphered within alternative PrPSc quaternary structures. So far it is unknown how prion strains target specific cells and initiate productive infections. Deeper mechanistic insight into the prion life cycle came from cell lines permissive to a range of different prion strains. Still, it is unknown why certain cell lines are refractory to infection by one strain but permissive to another. While pharmacologic and genetic manipulations revealed subcellular compartments involved in prion replication, little is known about strain-specific requirements for endocytic trafficking pathways. This review summarizes our knowledge on how prions replicate within their target cells and on strain-specific differences in prion cell biology.
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Affiliation(s)
- Ina M Vorberg
- German Center for Neurodegenerative Diseases (DZNE e.V.), Sigmund-Freud-Strasse 27, 53127 Bonn, Germany.
- Rheinische Friedrich-Wilhelms-Universität Bonn, 53127 Bonn, Germany.
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14
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Pellegrini L, Hauser DN, Li Y, Mamais A, Beilina A, Kumaran R, Wetzel A, Nixon-Abell J, Heaton G, Rudenko I, Alkaslasi M, Ivanina N, Melrose HL, Cookson MR, Harvey K. Proteomic analysis reveals co-ordinated alterations in protein synthesis and degradation pathways in LRRK2 knockout mice. Hum Mol Genet 2019; 27:3257-3271. [PMID: 29917075 PMCID: PMC6121185 DOI: 10.1093/hmg/ddy232] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 06/12/2018] [Indexed: 01/13/2023] Open
Abstract
Mutations in leucine-rich repeat kinase 2 (LRRK2) segregate with familial Parkinson’s disease (PD) and genetic variation around LRRK2 contributes to risk of sporadic disease. Although knockout (KO) of Lrrk2 or knock-in of pathogenic mutations into the mouse germline does not result in a PD phenotype, several defects have been reported in the kidneys of Lrrk2 KO mice. To understand LRRK2 function in vivo, we used an unbiased approach to determine which protein pathways are affected in LRRK2 KO kidneys. We nominated changes in cytoskeletal-associated proteins, lysosomal proteases, proteins involved in vesicular trafficking and in control of protein translation. Changes were not seen in mice expressing the pathogenic G2019S LRRK2 mutation. Using cultured epithelial kidney cells, we replicated the accumulation of lysosomal proteases and demonstrated changes in subcellular distribution of the cation-independent mannose-6-phosphate receptor. These results show that loss of LRRK2 leads to co-ordinated responses in protein translation and trafficking and argue against a dominant negative role for the G2019S mutation.
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Affiliation(s)
- Laura Pellegrini
- Cell Biology and Gene Expression Section, Laboratory of Neurogenetics, National Institute of Aging, National Institutes of Health, Bethesda, MD, USA.,Department of Pharmacology, UCL School of Pharmacy, University College London, London, UK
| | - David N Hauser
- Cell Biology and Gene Expression Section, Laboratory of Neurogenetics, National Institute of Aging, National Institutes of Health, Bethesda, MD, USA
| | - Yan Li
- Mass-spetrometry Facility, National Institute of Neurological Diseases and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Adamantios Mamais
- Cell Biology and Gene Expression Section, Laboratory of Neurogenetics, National Institute of Aging, National Institutes of Health, Bethesda, MD, USA
| | - Alexandra Beilina
- Cell Biology and Gene Expression Section, Laboratory of Neurogenetics, National Institute of Aging, National Institutes of Health, Bethesda, MD, USA
| | - Ravindran Kumaran
- Cell Biology and Gene Expression Section, Laboratory of Neurogenetics, National Institute of Aging, National Institutes of Health, Bethesda, MD, USA
| | - Andrea Wetzel
- Department of Pharmacology, UCL School of Pharmacy, University College London, London, UK
| | - Jonathon Nixon-Abell
- Department of Pharmacology, UCL School of Pharmacy, University College London, London, UK.,Neurogenetics Branch, National Institute of Neurological Disorders and Stroke - National Institutes of Health, Bethesda, MD, USA
| | - George Heaton
- Cell Biology and Gene Expression Section, Laboratory of Neurogenetics, National Institute of Aging, National Institutes of Health, Bethesda, MD, USA.,Department of Pharmacology, UCL School of Pharmacy, University College London, London, UK
| | - Iakov Rudenko
- Department of Neurology, SUNY at Stony Brook, Health Science Center, Stony Brook, NY, USA
| | - Mor Alkaslasi
- Cell Biology and Gene Expression Section, Laboratory of Neurogenetics, National Institute of Aging, National Institutes of Health, Bethesda, MD, USA
| | - Natalie Ivanina
- Cell Biology and Gene Expression Section, Laboratory of Neurogenetics, National Institute of Aging, National Institutes of Health, Bethesda, MD, USA
| | - Heather L Melrose
- Department of Neuroscience, Mayo Clinic Jacksonville, Jacksonville, FL, USA
| | - Mark R Cookson
- Cell Biology and Gene Expression Section, Laboratory of Neurogenetics, National Institute of Aging, National Institutes of Health, Bethesda, MD, USA
| | - Kirsten Harvey
- Department of Pharmacology, UCL School of Pharmacy, University College London, London, UK
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15
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Rab5-independent activation and function of yeast Rab7-like protein, Ypt7p, in the AP-3 pathway. PLoS One 2019; 14:e0210223. [PMID: 30682048 PMCID: PMC6347229 DOI: 10.1371/journal.pone.0210223] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Accepted: 12/18/2018] [Indexed: 11/19/2022] Open
Abstract
The small GTPases, Rab5 and Rab7, are key regulators at multiple stages of the endocytic/endolysosomal pathway, including fusion and maturation of endosomes. In yeast, Vps21p (Rab5 homolog) recruits a GEF for Rab7 and activates the downstream Ypt7p (Rab7 homolog) on endosomal membrane. Although the model of this sequential activation from Vps21p to Ypt7p in the endocytic pathway has been established, activation mechanism of Ypt7p in the Vps21p-independent pathway has not been completely clarified. Here we show that Ypt7p is activated and mediates vacuolar fusion in cells lacking all yeast Rab5 genes, VPS21, YPT52, and YPT53. We also demonstrate that deletion of both VPS21 and YPT7 genes cause severe defect in the AP-3 pathway as well as the CPY pathway although the AP-3 pathway is mostly intact in each vps21Δ or ypt7Δ mutant. Interestingly, in vps21Δ ypt7Δ mutant cargos trafficked via the VPS or endocytic pathway accumulate beside nucleus whereas cargo trafficked via the AP-3 pathway disperse in the cytosol. These findings suggest that Ypt7p is activated and plays a Rab5-independent role in the AP-3-mediated pathway.
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16
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Zhou L, Le Y, Tian J, Yang X, Jin R, Gai X, Sun Y. Cigarette smoke-induced RANKL expression enhances MMP-9 production by alveolar macrophages. Int J Chron Obstruct Pulmon Dis 2018; 14:81-91. [PMID: 30587964 PMCID: PMC6304243 DOI: 10.2147/copd.s190023] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Background and purpose Cigarette smoke (CS) induces alveolar destruction through overproduction of proteinases including matrix metalloproteinase (MMP)-9 by alveolar macrophages (AMs). Receptor activator of nuclear factor-κB ligand (RANKL) functions in immune regulation and cytokine secretion; whether it is involved in CS-induced MMP-9 expression is unknown. The purpose of our study was to investigate the expression and functional role of RANKL pathway in MMP-9 production pertaining to the pathogenesis of COPD. Materials and methods We first localized RANKL and its receptor RANK in the lungs of mice exposed to long-term CS exposure. Next, we studied RANKL and RANK expression under CS extract (CSE) stimulation in vitro. Lastly, we studied the in vitro biological function of RANKL in CS-induced production of MMP-9. Results Both RANKL and RANK were highly expressed in AMs in CS-exposed mice, but not in the control mice. In vitro, CSE increased the expressions of RANKL and RANK in macrophages. AMs responded to CSE and RANKL stimulation by overexpressing MMP-9, and CSE-induced MMP-9 expression was partly blocked by using monoclonal anti-RANKL antibody. Conclusion RANKL/RANK pathway mediates CS-induced MMP-9 expression in AMs, suggesting a novel mechanism for CS-associated emphysema.
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Affiliation(s)
- Lu Zhou
- Department of Respiratory Medicine, Peking University Third Hospital, Beijing, China,
| | - Yanqing Le
- Department of Respiratory Medicine, Peking University Third Hospital, Beijing, China,
| | - Jieyu Tian
- Department of Respiratory Medicine, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Xia Yang
- Department of Respiratory Medicine, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Rong Jin
- Department of Immunology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
| | - Xiaoyan Gai
- Department of Respiratory Medicine, Peking University Third Hospital, Beijing, China,
| | - Yongchang Sun
- Department of Respiratory Medicine, Peking University Third Hospital, Beijing, China,
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17
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Krause K, Caution K, Badr A, Hamilton K, Saleh A, Patel K, Seveau S, Hall-Stoodley L, Hegazi R, Zhang X, Gavrilin MA, Amer AO. CASP4/caspase-11 promotes autophagosome formation in response to bacterial infection. Autophagy 2018; 14:1928-1942. [PMID: 30165781 PMCID: PMC6152495 DOI: 10.1080/15548627.2018.1491494] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
CASP4/caspase-11-dependent inflammasome activation is important for the clearance of various Gram-negative bacteria entering the host cytosol. Additionally, CASP4 modulates the actin cytoskeleton to promote the maturation of phagosomes harboring intracellular pathogens such as Legionella pneumophila but not those enclosing nonpathogenic bacteria. Nevertheless, this non-inflammatory role of CASP4 regarding the trafficking of vacuolar bacteria remains poorly understood. Macroautophagy/autophagy, a catabolic process within eukaryotic cells, is also implicated in the elimination of intracellular pathogens such as Burkholderia cenocepacia. Here we show that CASP4-deficient macrophages exhibit a defect in autophagosome formation in response to B. cenocepacia infection. The absence of CASP4 causes an accumulation of the small GTPase RAB7, reduced colocalization of B. cenocepacia with LC3 and acidic compartments accompanied by increased bacterial replication in vitro and in vivo. Together, our data reveal a novel role of CASP4 in regulating autophagy in response to B. cenocepacia infection.
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Affiliation(s)
- Kathrin Krause
- a Department of Microbial Infection and Immunity , Infectious Diseases Institute , Columbus , OH , USA
| | - Kyle Caution
- a Department of Microbial Infection and Immunity , Infectious Diseases Institute , Columbus , OH , USA
| | - Asmaa Badr
- a Department of Microbial Infection and Immunity , Infectious Diseases Institute , Columbus , OH , USA
| | - Kaitlin Hamilton
- a Department of Microbial Infection and Immunity , Infectious Diseases Institute , Columbus , OH , USA
| | - Abdulmuti Saleh
- a Department of Microbial Infection and Immunity , Infectious Diseases Institute , Columbus , OH , USA
| | - Khushbu Patel
- a Department of Microbial Infection and Immunity , Infectious Diseases Institute , Columbus , OH , USA
| | - Stephanie Seveau
- a Department of Microbial Infection and Immunity , Infectious Diseases Institute , Columbus , OH , USA
| | - Luanne Hall-Stoodley
- a Department of Microbial Infection and Immunity , Infectious Diseases Institute , Columbus , OH , USA
| | - Rana Hegazi
- a Department of Microbial Infection and Immunity , Infectious Diseases Institute , Columbus , OH , USA
| | - Xiaoli Zhang
- b Center for Biostatistics, The Ohio State University , Columbus , OH , USA
| | - Mikhail A Gavrilin
- c Department of Internal Medicine , The Ohio State University , Columbus , OH , USA
| | - Amal O Amer
- a Department of Microbial Infection and Immunity , Infectious Diseases Institute , Columbus , OH , USA
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18
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Charfi I, Abdallah K, Gendron L, Pineyro G. Delta opioid receptors recycle to the membrane after sorting to the degradation path. Cell Mol Life Sci 2018; 75:2257-2271. [PMID: 29288293 PMCID: PMC11105734 DOI: 10.1007/s00018-017-2732-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Revised: 11/29/2017] [Accepted: 12/18/2017] [Indexed: 01/24/2023]
Abstract
Soon after internalization delta opioid receptors (DOPrs) are committed to the degradation path by G protein-coupled receptor (GPCR)-associated binding protein. Here we provide evidence that this classical post-endocytic itinerary may be rectified by downstream sorting decisions which allow DOPrs to regain to the membrane after having reached late endosomes (LE). The LE sorting mechanism involved ESCRT accessory protein Alix and the TIP47/Rab9 retrieval complex which supported translocation of the receptor to the TGN, from where it subsequently regained the cell membrane. Preventing DOPrs from completing this itinerary precipitated acute analgesic tolerance to the agonist DPDPE, supporting the relevance of this recycling path in maintaining the analgesic response by this receptor. Taken together, these findings reveal a post-endocytic itinerary where GPCRs that have been sorted for degradation can still recycle to the membrane.
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Affiliation(s)
- Iness Charfi
- Department of Pharmacology, University of Montreal, Montreal, Quebec, H3T 1J4, Canada
- Ste-Justine Hospital, Montreal, Quebec, H3T 1C5, Canada
| | - Khaled Abdallah
- Department of Pharmacology-physiology, University of Sherbrooke, Sherbrooke, Quebec, J1H 5N4, Canada
| | - Louis Gendron
- Department of Pharmacology-physiology, University of Sherbrooke, Sherbrooke, Quebec, J1H 5N4, Canada
| | - Graciela Pineyro
- Department of Pharmacology, University of Montreal, Montreal, Quebec, H3T 1J4, Canada.
- Department of Psychiatry, University of Montreal, Montreal, Quebec, H3T 1J4, Canada.
- Ste-Justine Hospital, Montreal, Quebec, H3T 1C5, Canada.
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19
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Garcia EJ, Vevea JD, Pon LA. Lipid droplet autophagy during energy mobilization, lipid homeostasis and protein quality control. Front Biosci (Landmark Ed) 2018; 23:1552-1563. [PMID: 29293450 DOI: 10.2741/4660] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Lipid droplets (LDs) have well-established functions as sites for lipid storage and energy mobilization to meet the metabolic demands of cells. However, recent studies have expanded the roles of LDs to protein quality control. Lipophagy, or LD degradation by autophagy, plays a vital role not only in the mobilization of free fatty acids (FFAs) and lipid homeostasis at LDs, but also in the adaptation of cells to certain forms of stress including lipid imbalance. Recent studies have provided new mechanistic insights about the diverse types of lipophagy, in particular microlipophagy. This review summarizes key findings about the mechanisms and functions of lipophagy and highlights a novel function of LD microlipophagy as a mechanism to maintain endoplasmic reticulum (ER) proteostasis under conditions of lipid imbalance.
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Affiliation(s)
- Enrique J Garcia
- Department of Pathology and Cell Biology, Columbia University, New York, NY, 10032 USA
| | - Jason D Vevea
- HHMI and Dept. of Neuroscience, University of Wisconsin, Madison, WI, 53705 USA
| | - Liza A Pon
- Department of Pathology and Cell Biology, Columbia University, New York, NY, 10032 USA,
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20
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Zhang C, Zhou X, Yao T, Tian Z, Zhou D. Precision Fluorescent Labeling of an Adeno-Associated Virus Vector to Monitor the Viral Infection Pathway. Biotechnol J 2018; 13:e1700374. [DOI: 10.1002/biot.201700374] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Revised: 12/04/2017] [Indexed: 11/07/2022]
Affiliation(s)
- Chuanling Zhang
- State Key Laboratory of Natural and Biomimetic Drugs; School of Pharmaceutical Sciences; Peking University; Beijing 100191 China
| | - Xueying Zhou
- State Key Laboratory of Natural and Biomimetic Drugs; School of Pharmaceutical Sciences; Peking University; Beijing 100191 China
| | - Tianzhuo Yao
- State Key Laboratory of Natural and Biomimetic Drugs; School of Pharmaceutical Sciences; Peking University; Beijing 100191 China
| | - Zhenyu Tian
- State Key Laboratory of Natural and Biomimetic Drugs; School of Pharmaceutical Sciences; Peking University; Beijing 100191 China
| | - Demin Zhou
- State Key Laboratory of Natural and Biomimetic Drugs; School of Pharmaceutical Sciences; Peking University; Beijing 100191 China
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21
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Romano JD, Nolan SJ, Porter C, Ehrenman K, Hartman EJ, Hsia RC, Coppens I. The parasite Toxoplasma sequesters diverse Rab host vesicles within an intravacuolar network. J Cell Biol 2017; 216:4235-4254. [PMID: 29070609 PMCID: PMC5716271 DOI: 10.1083/jcb.201701108] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Revised: 07/28/2017] [Accepted: 09/08/2017] [Indexed: 02/01/2023] Open
Abstract
Many intracellular pathogens subvert host membrane trafficking pathways to promote their replication. Toxoplasma multiplies in a membrane-bound parasitophorous vacuole (PV) that interacts with mammalian host organelles and intercepts Golgi Rab vesicles to acquire sphingolipids. The mechanisms of host vesicle internalization and processing within the PV remain undefined. We demonstrate that Toxoplasma sequesters a broad range of Rab vesicles into the PV. Correlative light and electron microscopy analysis of infected cells illustrates that intravacuolar Rab1A vesicles are surrounded by the PV membrane, suggesting a phagocytic-like process for vesicle engulfment. Rab11A vesicles concentrate to an intravacuolar network (IVN), but this is reduced in Δgra2 and Δgra2Δgra6 parasites, suggesting that tubules stabilized by the TgGRA2 and TgGRA6 proteins secreted by the parasite within the PV contribute to host vesicle sequestration. Overexpression of a phospholipase TgLCAT, which is localized to the IVN, results in a decrease in the number of intravacuolar GFP-Rab11A vesicles, suggesting that TgLCAT controls lipolytic degradation of Rab vesicles for cargo release.
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Affiliation(s)
- Julia D. Romano
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD,Julia D. Romano:
| | - Sabrina J. Nolan
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD
| | - Corey Porter
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD
| | - Karen Ehrenman
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD
| | - Eric J. Hartman
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD
| | - Ru-ching Hsia
- Electron Microscopy Core Imaging Facility, University of Maryland Baltimore, Baltimore, MD
| | - Isabelle Coppens
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD,Correspondence to Isabelle Coppens: ;
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22
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Sun H, Liu Y, Zhang L, Shao X, Liu K, Ding Z, Liu X, Jiang C, Li H, Li H. Numb positively regulates autophagic flux via regulating lysosomal function. Biochem Biophys Res Commun 2017; 491:780-786. [PMID: 28720501 DOI: 10.1016/j.bbrc.2017.07.084] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Accepted: 07/14/2017] [Indexed: 11/15/2022]
Abstract
Autophagy is a lysosome-dependent catabolic process involving in the degradation and recycling of unnecessary or damaged proteins and organelles. Emerging evidence indicates that autophagy dysfunction is closely related to various human diseases including cancer, aging, myopathies and neurodegenerative disorders. Here, using genetic knockdown, we uncover the role of Numb, an endocytic adaptor protein, in regulating the late steps of autophagy. We found that Numb depletion led to the accumulation of autophagic vacuole, as verified by RFP-LC3 staining combined with transmission electron microscopy. Further investigation indicated that Numb depletion impaired autophagic degradation through inhibiting the activities of lysosomal enzymes (Cathepsin D, β-glucuronidase and β-glucosidase). Moreover, Numb depletion induced elevation of lysosomal pH values and decrease of glycosylated lysosome-associated membrane proteins. We further observed that Rab7 activity was inhibited in Numb-depleted cells. Together, our findings revealed a novel function of Numb and its likely mechanism in regulation of autophagy events.
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Affiliation(s)
- Haiyan Sun
- Shenzhen Key Laboratory for Molecular Biology of Neural Development, Guangdong Key Laboratory of Nanomedicine, Institute of Biomedicine and Biotechnology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong 518055, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yi Liu
- Shenzhen Key Laboratory for Molecular Biology of Neural Development, Guangdong Key Laboratory of Nanomedicine, Institute of Biomedicine and Biotechnology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong 518055, China
| | - Lei Zhang
- Shenzhen Key Laboratory for Molecular Biology of Neural Development, Guangdong Key Laboratory of Nanomedicine, Institute of Biomedicine and Biotechnology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong 518055, China
| | - Ximing Shao
- Shenzhen Key Laboratory for Molecular Biology of Neural Development, Guangdong Key Laboratory of Nanomedicine, Institute of Biomedicine and Biotechnology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong 518055, China
| | - Ke Liu
- Shenzhen Key Laboratory for Molecular Biology of Neural Development, Guangdong Key Laboratory of Nanomedicine, Institute of Biomedicine and Biotechnology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong 518055, China
| | - Zhihao Ding
- Shenzhen Key Laboratory for Molecular Biology of Neural Development, Guangdong Key Laboratory of Nanomedicine, Institute of Biomedicine and Biotechnology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong 518055, China
| | - Xianming Liu
- Shenzhen Key Laboratory for Molecular Biology of Neural Development, Guangdong Key Laboratory of Nanomedicine, Institute of Biomedicine and Biotechnology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong 518055, China; College of Life Science and Technology, Jinan University, 601 West Huangpu Blvd., Guangzhou 510632, China
| | - Changan Jiang
- Shenzhen Key Laboratory for Molecular Biology of Neural Development, Guangdong Key Laboratory of Nanomedicine, Institute of Biomedicine and Biotechnology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong 518055, China
| | - Huashun Li
- SARITEX Center for Stem Cell Engineering Translational Medicine, Shanghai East Hospital, Tongji University School of Medicine, Advanced Institute of Translational Medicine, Shanghai 200123, China; ATCG Corporation, BioBay, Suzhou Industrial Park, Suzhou, Jiangsu 215123, China
| | - Hongchang Li
- Shenzhen Key Laboratory for Molecular Biology of Neural Development, Guangdong Key Laboratory of Nanomedicine, Institute of Biomedicine and Biotechnology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong 518055, China.
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23
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Liu K, Xing R, Jian Y, Gao Z, Ma X, Sun X, Li Y, Xu M, Wang X, Jing Y, Guo W, Yang C. WDR91 is a Rab7 effector required for neuronal development. J Cell Biol 2017; 216:3307-3321. [PMID: 28860274 PMCID: PMC5626554 DOI: 10.1083/jcb.201705151] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 07/03/2017] [Accepted: 07/12/2017] [Indexed: 12/22/2022] Open
Abstract
Early-to-late endosome conversion involves switching of early endosomes Rab5 and PtdIns3P to late endosomes Rab7 and PtdIns(3,5)P2. Liu et al. identify WDR91 as a Rab7 effector that couples Rab switching with PtdIns3P down-regulation on endosomes and show that WDR91 is essential for neuronal development. Early-to-late endosome conversion, which is essential for delivery of endosomal cargoes to lysosomes, requires switching of early endosome–specific Rab5 and PtdIns3P to late endosome–specific Rab7 and PtdIns(3,5)P2. In this study, we identify the WD40-repeat protein WDR91 as a Rab7 effector that couples Rab switching with PtdIns3P down-regulation on endosomes. Loss of WDR91 greatly increases endosomal PtdIns3P levels, arresting endosomes at an intermediate stage and blocking endosomal–lysosomal trafficking. WDR91 is recruited to endosomes by interacting with active guanosine triphosophate–Rab7 and inhibits Rab7-associated phosphatidylinositol 3-kinase activity. In mice, global Wdr91 knockout causes neonatal death, whereas brain-specific Wdr91 inactivation impairs brain development and causes postnatal death. Mouse neurons lacking Wdr91 accumulate giant intermediate endosomes and exhibit reduced neurite length and complexity. These phenotypes are rescued by WDR91 but not WDR91 mutants that cannot interact with Rab7. Thus, WDR91 serves as a Rab7 effector that is essential for neuronal development by facilitating endosome conversion in the endosome–lysosome pathway.
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Affiliation(s)
- Kai Liu
- State Key Laboratory of Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.,State Key Laboratory of Natural Resource Conservation and Utilization in Yunnan and Center for Life Science, School of Life Sciences, Yunnan University, Kunming, China
| | - Ruxiao Xing
- State Key Laboratory of Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.,Graduate University of Chinese Academy of Sciences, Beijing, China
| | - Youli Jian
- State Key Laboratory of Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Zhiyang Gao
- State Key Laboratory of Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Xinli Ma
- Graduate University of Chinese Academy of Sciences, Beijing, China.,Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Xiaojuan Sun
- State Key Laboratory of Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Yang Li
- State Key Laboratory of Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Meng Xu
- State Key Laboratory of Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Xin Wang
- State Key Laboratory of Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.,State Key Laboratory of Natural Resource Conservation and Utilization in Yunnan and Center for Life Science, School of Life Sciences, Yunnan University, Kunming, China
| | - Yudong Jing
- State Key Laboratory of Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Weixiang Guo
- State Key Laboratory of Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Chonglin Yang
- State Key Laboratory of Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China .,State Key Laboratory of Natural Resource Conservation and Utilization in Yunnan and Center for Life Science, School of Life Sciences, Yunnan University, Kunming, China
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24
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Kage F, Steffen A, Ellinger A, Ranftler C, Gehre C, Brakebusch C, Pavelka M, Stradal T, Rottner K. FMNL2 and -3 regulate Golgi architecture and anterograde transport downstream of Cdc42. Sci Rep 2017; 7:9791. [PMID: 28852060 PMCID: PMC5575334 DOI: 10.1038/s41598-017-09952-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Accepted: 07/26/2017] [Indexed: 01/08/2023] Open
Abstract
The Rho-family small GTPase Cdc42 localizes at plasma membrane and Golgi complex and aside from protrusion and migration operates in vesicle trafficking, endo- and exocytosis as well as establishment and/or maintenance of cell polarity. The formin family members FMNL2 and -3 are actin assembly factors established to regulate cell edge protrusion during migration and invasion. Here we report these formins to additionally accumulate and function at the Golgi apparatus. As opposed to lamellipodia, Golgi targeting of these proteins required both their N-terminal myristoylation and the interaction with Cdc42. Moreover, Golgi association of FMNL2 or -3 induced a phalloidin-detectable actin meshwork around the Golgi. Importantly, functional interference with FMNL2/3 formins by RNAi or CRISPR/Cas9-mediated gene deletion invariably induced Golgi fragmentation in different cell lines. Furthermore, absence of these proteins led to enlargement of endosomes as well as defective maturation and/or sorting into late endosomes and lysosomes. In line with Cdc42 - recently established to regulate anterograde transport through the Golgi by cargo sorting and carrier formation - FMNL2/3 depletion also affected anterograde trafficking of VSV-G from the Golgi to the plasma membrane. Our data thus link FMNL2/3 formins to actin assembly-dependent functions of Cdc42 in anterograde transport through the Golgi apparatus.
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Affiliation(s)
- Frieda Kage
- Division of Molecular Cell Biology, Zoological Institute, Technische Universität Braunschweig, Spielmannstrasse 7, 38106, Braunschweig, Germany.,Department of Cell Biology, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124, Braunschweig, Germany
| | - Anika Steffen
- Department of Cell Biology, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124, Braunschweig, Germany
| | - Adolf Ellinger
- Center for Anatomy and Cell Biology, Medical University of Vienna, Schwarzspanierstraße 17, 1090, Vienna, Austria
| | - Carmen Ranftler
- Center for Anatomy and Cell Biology, Medical University of Vienna, Schwarzspanierstraße 17, 1090, Vienna, Austria
| | - Christian Gehre
- Division of Molecular Cell Biology, Zoological Institute, Technische Universität Braunschweig, Spielmannstrasse 7, 38106, Braunschweig, Germany.,Department of Cell Biology, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124, Braunschweig, Germany
| | - Cord Brakebusch
- Biomedical Institute, BRIC, University of Copenhagen, DK-2200, Copenhagen, Denmark
| | - Margit Pavelka
- Center for Anatomy and Cell Biology, Medical University of Vienna, Schwarzspanierstraße 17, 1090, Vienna, Austria
| | - Theresia Stradal
- Department of Cell Biology, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124, Braunschweig, Germany
| | - Klemens Rottner
- Division of Molecular Cell Biology, Zoological Institute, Technische Universität Braunschweig, Spielmannstrasse 7, 38106, Braunschweig, Germany. .,Department of Cell Biology, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124, Braunschweig, Germany.
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25
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Takahashi K, Mashima H, Miura K, Maeda D, Goto A, Goto T, Sun-Wada GH, Wada Y, Ohnishi H. Disruption of Small GTPase Rab7 Exacerbates the Severity of Acute Pancreatitis in Experimental Mouse Models. Sci Rep 2017; 7:2817. [PMID: 28588238 PMCID: PMC5460112 DOI: 10.1038/s41598-017-02988-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Accepted: 04/21/2017] [Indexed: 01/25/2023] Open
Abstract
Although aberrations of intracellular vesicle transport systems towards lysosomes including autophagy and endocytosis are involved in the onset and progression of acute pancreatitis, the molecular mechanisms underlying such aberrations remain unclear. The pathways of autophagy and endocytosis are closely related, and Rab7 plays crucial roles in both. In this study, we analyzed the function of Rab7 in acute pancreatitis using pancreas-specific Rab7 knockout (Rab7Δpan) mice. In Rab7Δpan pancreatic acinar cells, the maturation steps of both endosomes and autophagosomes were deteriorated, and the lysosomal functions were affected. In experimental models of acute pancreatitis, the histopathological severity, serum amylase concentration and intra-pancreatic trypsin activity were significantly higher in Rab7Δpan mice than in wild-type mice. Furthermore, the autophagy process was blocked in Rab7Δpan pancreas compared with wild-type mice. In addition, larger autophagic vacuoles that colocalize with early endosome antigen 1 (EEA1) but not with lysosomal-associated membrane protein (LAMP)-1 were much more frequently formed in Rab7Δpan pancreatic acinar cells. Accordingly, Rab7 deficiency exacerbates the severity of acute pancreatitis by impairing the autophagic and endocytic pathways toward lysosomes.
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Affiliation(s)
- Kenichi Takahashi
- Department of Gastroenterology and Hepato-Biliary-Pancreatology, Akita University Graduate School of Medicine, Akita, Japan
| | - Hirosato Mashima
- Department of Gastroenterology, Saitama Medical Center, Jichi Medical University, Saitama, Japan
| | - Kouichi Miura
- Department of Gastroenterology and Hepato-Biliary-Pancreatology, Akita University Graduate School of Medicine, Akita, Japan
| | - Daichi Maeda
- Department of Cellular and Organ Pathology, Akita University Graduate School of Medicine, Akita, Japan
| | - Akiteru Goto
- Department of Cellular and Organ Pathology, Akita University Graduate School of Medicine, Akita, Japan
| | - Takashi Goto
- Department of Gastroenterology and Hepato-Biliary-Pancreatology, Akita University Graduate School of Medicine, Akita, Japan
| | - Ge-Hong Sun-Wada
- Department of Biochemistry, Faculty of Pharmaceutical Sciences, Doshisha Women's College, Kyoto, Japan
| | - Yoh Wada
- Division of Biological Science, Institute of Scientific and Industrial Research, Osaka University, Osaka, Japan
| | - Hirohide Ohnishi
- Department of Gastroenterology, Saitama Medical Center, Jichi Medical University, Saitama, Japan.
- Japan Organization of Occupational Health and Safety, Kanagawa, Japan.
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26
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Rodriguez L, Mohamed NV, Desjardins A, Lippé R, Fon EA, Leclerc N. Rab7A regulates tau secretion. J Neurochem 2017; 141:592-605. [PMID: 28222213 DOI: 10.1111/jnc.13994] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Revised: 02/10/2017] [Accepted: 02/16/2017] [Indexed: 12/20/2022]
Abstract
The axonal microtubule-associated protein TAU, involved in Alzheimer's disease (AD), can be found in the extracellular space where it could be taken up by neurons, an event that is believed to contribute to the propagation of tau pathology in the brain. Since the small GTPase Rab7A is involved in the trafficking of endosomes, autophagosomes, and lysosomes, and RAB7A gene expression and protein levels are up-regulated in AD patients, we tested the hypothesis that Rab7A was involved in tau secretion. We previously reported that both primary cortical neurons and HeLa cells over-expressing human TAU can release tau. Using these two cellular systems, we demonstrated that Rab7A regulates tau secretion. Upon Rab7A deletion, tau secretion was decreased. Consistent with this, the over-expression of a dominant negative and a constitutively active form of Rab7A decreased and increased tau secretion, respectively. A partial co-localization of tau and Rab7-positive structures in both neurons and HeLa cells indicated that a late endosomal compartment could be involved in its secretion. Collectively, the present data indicate that Rab7A regulates tau secretion and therefore the up-regulation of RAB7A reported in AD, could contribute to the extracellular accumulation of pathological TAU species that could result in the propagation of tau pathology in the AD brain.
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Affiliation(s)
- Lilia Rodriguez
- Research Center of the University of Montreal Hospital (CRCHUM), Montréal, Québec, Canada.,CNS Research Group (GRSNC), Montreal, Québec, Canada.,Département de Neurosciences, Faculty of Medicine, Université de Montréal, Montréal, Québec, Canada
| | - Nguyen-Vi Mohamed
- Research Center of the University of Montreal Hospital (CRCHUM), Montréal, Québec, Canada.,CNS Research Group (GRSNC), Montreal, Québec, Canada.,Département de Neurosciences, Faculty of Medicine, Université de Montréal, Montréal, Québec, Canada
| | - Alexandre Desjardins
- Research Center of the University of Montreal Hospital (CRCHUM), Montréal, Québec, Canada.,CNS Research Group (GRSNC), Montreal, Québec, Canada.,Département de Neurosciences, Faculty of Medicine, Université de Montréal, Montréal, Québec, Canada
| | - Roger Lippé
- Département de pathologie et biologie cellulaire, Faculty of Medicine, Université de Montréal, Montréal, Québec, Canada
| | - Edward A Fon
- McGill Parkinson Program, Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montréal, Québec, Canada
| | - Nicole Leclerc
- Research Center of the University of Montreal Hospital (CRCHUM), Montréal, Québec, Canada.,CNS Research Group (GRSNC), Montreal, Québec, Canada.,Département de Neurosciences, Faculty of Medicine, Université de Montréal, Montréal, Québec, Canada
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27
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Pérez-Montesinos G, López-Ortega O, Piedra-Reyes J, Bonifaz LC, Moreno J. Dynamic Changes in the Intracellular Association of Selected Rab Small GTPases with MHC Class II and DM during Dendritic Cell Maturation. Front Immunol 2017; 8:340. [PMID: 28396666 PMCID: PMC5367080 DOI: 10.3389/fimmu.2017.00340] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Accepted: 03/09/2017] [Indexed: 01/13/2023] Open
Abstract
Antigen processing for presentation by major histocompatibility complex class II (MHCII) molecules requires the latter to travel through the endocytic pathway together with its chaperons: the invariant chain (Ii) and DM. Nevertheless, the nature of the compartments where MHCII molecules travel to acquire peptides lacks definition regarding molecules involved in intracellular vesicular trafficking, such as Rab small GTPases. We aimed to define which Rab proteins are present during the intracellular transport of MHCII, DM, and Ii through the endocytic pathway on their route to the cell surface during dendritic cell (DC) maturation. We examined, by means of three-color confocal microscopy, the association of MHCII, DM, and Ii with Rab5, Rab7, Rab9, and Rab11 during the maturation of bone marrow-derived or spleen DC in response to LPS as an inflammatory stimulus. Prior to the stage of immature DC, MHCII migrated from diffuse small cytoplasmic vesicles, predominantly Rab5+Rab7- and Rab5+Rab7+ into a pericentriolar Rab5+Rab7+Rab9+ cluster, with Rab11+ areas. As DC reached the mature phenotype, MHCII left the pericentriolar endocytic compartments toward the cell surface in Rab11+ and Rab9+Rab11+ vesicles. The invariant chain and MHCII transport pathways were not identical. DM and MHCII appeared to arrive to pericentriolar endocytic compartments of immature DC through partially different routes. The association of MHCII molecules with distinct Rab GTPases during DC maturation suggests that after leaving the biosynthetic pathway, MHCII sequentially traffic from typical early endosomes to multivesicular late endosomes to finally arrive at the cell surface in Rab11+ recycling-type endosomes. In immature DCs, DM encounters transiently MHCII in the Rab5+Rab7+Rab9+ compartments, to remain there in mature DC.
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Affiliation(s)
- Gibrán Pérez-Montesinos
- Research Unit on Autoimmune Diseases, Research Unit on Immunochemistry, Centro México Nacional Siglo XXI, IMSS, Instituto Mexicano del Seguro Social, Mexico City, Distrito Federal, Mexico
- Centro Dermatológico “Dr. Ladislao de la Pascua”, Secretaría de Salud del Distrito Federal, Mexico City, Distrito Federal, Mexico
| | - Orestes López-Ortega
- Hospital Juárez de México, Secretaría de Salud, Mexico City, Distrito Federal, Mexico
| | - Jessica Piedra-Reyes
- Hospital Juárez de México, Secretaría de Salud, Mexico City, Distrito Federal, Mexico
| | - Laura C. Bonifaz
- Research Unit on Autoimmune Diseases, Research Unit on Immunochemistry, Centro México Nacional Siglo XXI, IMSS, Instituto Mexicano del Seguro Social, Mexico City, Distrito Federal, Mexico
| | - José Moreno
- Research Unit on Autoimmune Diseases, Research Unit on Immunochemistry, Centro México Nacional Siglo XXI, IMSS, Instituto Mexicano del Seguro Social, Mexico City, Distrito Federal, Mexico
- Hospital Juárez de México, Secretaría de Salud, Mexico City, Distrito Federal, Mexico
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28
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Wen H, Zhan L, Chen S, Long L, Xu E. Rab7 may be a novel therapeutic target for neurologic diseases as a key regulator in autophagy. J Neurosci Res 2017; 95:1993-2004. [PMID: 28186670 DOI: 10.1002/jnr.24034] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 01/17/2017] [Accepted: 01/17/2017] [Indexed: 12/14/2022]
Affiliation(s)
- Haixia Wen
- Institute of Neuroscience and Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University and Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China; Guangzhou China
| | - Lixuan Zhan
- Institute of Neuroscience and Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University and Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China; Guangzhou China
| | - Siyuan Chen
- Institute of Neuroscience and Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University and Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China; Guangzhou China
| | - Long Long
- Institute of Neuroscience and Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University and Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China; Guangzhou China
| | - En Xu
- Institute of Neuroscience and Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University and Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China; Guangzhou China
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29
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Jacomin AC, Fauvarque MO, Taillebourg E. A functional endosomal pathway is necessary for lysosome biogenesis in Drosophila. BMC Cell Biol 2016; 17:36. [PMID: 27852225 PMCID: PMC5112658 DOI: 10.1186/s12860-016-0115-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Accepted: 11/05/2016] [Indexed: 12/21/2022] Open
Abstract
Background Lysosomes are the major catabolic compartment within eukaryotic cells, and their biogenesis requires the integration of the biosynthetic and endosomal pathways. Endocytosis and autophagy are the primary inputs of the lysosomal degradation pathway. Endocytosis is specifically needed for the degradation of membrane proteins whereas autophagy is responsible for the degradation of cytoplasmic components. We previously identified the deubiquitinating enzyme UBPY/USP8 as being necessary for lysosomal biogenesis and productive autophagy in Drosophila. Because UBPY/USP8 has been widely described for its function in the endosomal system, we hypothesized that disrupting the endosomal pathway itself may affect the biogenesis of the lysosomes. Results In the present study, we blocked the progression of the endosomal pathway at different levels of maturation of the endosomes by expressing in fat body cells either dsRNAs or dominant negative mutants targeting components of the endosomal machinery: Shibire, Rab4, Rab5, Chmp1 and Rab7. We observed that inhibition of endosomal trafficking at different steps in vivo is systematically associated with defects in lysosome biogenesis, resulting in autophagy flux blockade. Conclusion Our results show that the integrity of the endosomal system is required for lysosome biogenesis and productive autophagy in vivo. Electronic supplementary material The online version of this article (doi:10.1186/s12860-016-0115-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Anne-Claire Jacomin
- Université Grenoble-Alpes, F-38041, Grenoble, France.,CEA-DSV-iRTSV-BGE-Gen&Chem, 17, rue des Martyrs, 38054, Grenoble, Cedex 9, France.,INSERM, U1038, F-38054, Grenoble, France.,Present address: School of Life Sciences, University of Warwick, Coventry, UK
| | - Marie-Odile Fauvarque
- Université Grenoble-Alpes, F-38041, Grenoble, France. .,CEA-DSV-iRTSV-BGE-Gen&Chem, 17, rue des Martyrs, 38054, Grenoble, Cedex 9, France. .,INSERM, U1038, F-38054, Grenoble, France.
| | - Emmanuel Taillebourg
- Université Grenoble-Alpes, F-38041, Grenoble, France. .,CEA-DSV-iRTSV-BGE-Gen&Chem, 17, rue des Martyrs, 38054, Grenoble, Cedex 9, France. .,INSERM, U1038, F-38054, Grenoble, France.
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30
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Multiple Roles of the Small GTPase Rab7. Cells 2016; 5:cells5030034. [PMID: 27548222 PMCID: PMC5040976 DOI: 10.3390/cells5030034] [Citation(s) in RCA: 267] [Impact Index Per Article: 33.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Revised: 08/11/2016] [Accepted: 08/12/2016] [Indexed: 12/16/2022] Open
Abstract
Rab7 is a small GTPase that belongs to the Rab family and controls transport to late endocytic compartments such as late endosomes and lysosomes. The mechanism of action of Rab7 in the late endocytic pathway has been extensively studied. Rab7 is fundamental for lysosomal biogenesis, positioning and functions, and for trafficking and degradation of several signaling receptors, thus also having implications on signal transduction. Several Rab7 interacting proteins have being identified leading to the discovery of a number of different important functions, beside its established role in endocytosis. Furthermore, Rab7 has specific functions in neurons. This review highlights and discusses the role and the importance of Rab7 on different cellular pathways and processes.
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31
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Zhou J, Li G, Zheng Y, Shen HM, Hu X, Ming QL, Huang C, Li P, Gao N. A novel autophagy/mitophagy inhibitor liensinine sensitizes breast cancer cells to chemotherapy through DNM1L-mediated mitochondrial fission. Autophagy 2016; 11:1259-79. [PMID: 26114658 DOI: 10.1080/15548627.2015.1056970] [Citation(s) in RCA: 178] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Autophagy inhibition has been widely accepted as a promising therapeutic strategy in cancer, while the lack of effective and specific autophagy inhibitors hinders its application. Here we found that liensinine, a major isoquinoline alkaloid, inhibits late-stage autophagy/mitophagy through blocking autophagosome-lysosome fusion. This effect is likely achieved via inhibiting the recruitment of RAB7A to lysosomes but not to autophagosomes. We further investigated the effects of autophagy inhibition by liensinine on the therapeutic efficacy of chemotherapeutic drugs and found that cotreatment of liensinine markedly decreased the viability and increased apoptosis in breast cancer cells treated with various chemotherapeutic agents. Mechanistically, we found that inhibition of autophagy/mitophagy by liensinine enhanced doxorubicin-mediated apoptosis by triggering mitochondrial fission, which resulted from dephosphorylation and mitochondrial translocation of DNM1L. However, blocking autophagosome/mitophagosome formation by pharmacological or genetic approaches markedly attenuated mitochondrial fission and apoptosis in cells with combinatatorial treatment. Moreover, liensinine was synergized with doxorubicin to inhibit tumor growth in MDA-MB-231 xenograft in vivo. Our findings suggest that liensinine could potentially be further developed as a novel autophagy/mitophagy inhibitor, and a combination of liensinine with classical chemotherapeutic drugs could represent a novel therapeutic strategy for treatment of breast cancer.
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Affiliation(s)
- Jing Zhou
- a College of Pharmacy; 3rd Military Medical University ; Chongqing , China
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32
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Larkin H, Costantino S, Seaman MNJ, Lavoie C. Calnuc Function in Endosomal Sorting of Lysosomal Receptors. Traffic 2016; 17:416-32. [DOI: 10.1111/tra.12374] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 01/06/2016] [Accepted: 01/06/2016] [Indexed: 02/04/2023]
Affiliation(s)
- Heidi Larkin
- Department of Pharmacology, Faculty of Medicine and Health Sciences; Université de Sherbrooke; Sherbrooke QC Canada
| | - Santiago Costantino
- Centre de recherche de l'Hôpital Maisonneuve-Rosemont; Université de Montréal; Montréal H1T 2M Canada
| | - Matthew N. J. Seaman
- Cambridge Institute for Medical Research, Department of Clinical Biochemistry, Wellcome Trust/MRC Building, Addenbrookes Hospital; University of Cambridge; Cambridge CB2 0XY UK
| | - Christine Lavoie
- Department of Pharmacology, Faculty of Medicine and Health Sciences; Université de Sherbrooke; Sherbrooke QC Canada
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33
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Bahl S, Parashar S, Malhotra H, Raje M, Mukhopadhyay A. Functional Characterization of Monomeric GTPase Rab1 in the Secretory Pathway of Leishmania. J Biol Chem 2015; 290:29993-30005. [PMID: 26499792 DOI: 10.1074/jbc.m115.670018] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Indexed: 12/20/2022] Open
Abstract
Leishmania secretes a large number of its effectors to the extracellular milieu. However, regulation of the secretory pathway in Leishmania is not well characterized. Here, we report the cloning, expression, and characterization of the Rab1 homologue from Leishmania. We have found that LdRab1 localizes in Golgi in Leishmania. To understand the role of LdRab1 in the secretory pathway of Leishmania, we have generated transgenic parasites overexpressing GFP-LdRab1:WT, GFP-LdRab1:Q67L (a GTPase-deficient dominant positive mutant of Rab1), and GFP-LdRab1:S22N (a GDP-locked dominant negative mutant of Rab1). Surprisingly, our results have shown that overexpression of GFP-LdRab1:Q67L or GFP-LdRab1:S22N does not disrupt the trafficking and localization of hemoglobin receptor in Leishmania. To determine whether the Rab1-dependent secretory pathway is conserved in parasites, we have analyzed the role of LdRab1 in the secretion of secretory acid phosphatase and Ldgp63 in Leishmania. Our results have shown that overexpression of GFP-LdRab1:Q67L or GFP-LdRab1:S22N significantly inhibits the secretion of secretory acid phosphatase by Leishmania. We have also found that overexpression of GFP-LdRab1:Q67L or GFP-LdRab1:S22N retains RFP-Ldgp63 in Golgi and blocks the secretion of Ldgp63, whereas the trafficking of RFP-Ldgp63 in GFP-LdRab1:WT-expressing cells is unaltered in comparison with control cells. Taken together, our results have shown that the Rab1-regulated secretory pathway is well conserved, and hemoglobin receptor trafficking follows an Rab1-independent secretory pathway in Leishmania.
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Affiliation(s)
- Surbhi Bahl
- From the National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110067, India and
| | - Smriti Parashar
- From the National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110067, India and
| | | | - Manoj Raje
- the Institute of Microbial Technology, Chandigarh 160036, India
| | - Amitabha Mukhopadhyay
- From the National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110067, India and
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34
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Abstract
Postsynaptic AMPA-type glutamate receptors (AMPARs) are among the major determinants of synaptic strength and can be trafficked into and out of synapses. Neuronal activity regulates AMPAR trafficking during synaptic plasticity to induce long-term changes in synaptic strength, including long-term potentiation (LTP) and long-term depression (LTD). Rab family GTPases regulate most membrane trafficking in eukaryotic cells; particularly, Rab11 and its effectors are implicated in mediating postsynaptic AMPAR insertion during LTP. To explore the synaptic function of Rab11Fip5, a neuronal Rab11 effector and a candidate autism-spectrum disorder gene, we performed shRNA-mediated knock-down and genetic knock-out (KO) studies. Surprisingly, we observed robust shRNA-induced synaptic phenotypes that were rescued by a Rab11Fip5 cDNA but that were nevertheless not observed in conditional KO neurons. Both in cultured neurons and acute slices, KO of Rab11Fip5 had no significant effect on basic parameters of synaptic transmission, indicating that Rab11Fip5 is not required for fundamental synaptic operations, such as neurotransmitter release or postsynaptic AMPAR insertion. KO of Rab11Fip5 did, however, abolish hippocampal LTD as measured both in acute slices or using a chemical LTD protocol in cultured neurons but did not affect hippocampal LTP. The Rab11Fip5 KO mice performed normally in several behavioral tasks, including fear conditioning, but showed enhanced contextual fear extinction. These are the first findings to suggest a requirement for Rab11Fip5, and presumably Rab11, during LTD.
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35
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de Madrid BH, Greenberg L, Hatini V. RhoGAP68F controls transport of adhesion proteins in Rab4 endosomes to modulate epithelial morphogenesis of Drosophila leg discs. Dev Biol 2015; 399:283-95. [PMID: 25617722 PMCID: PMC4352398 DOI: 10.1016/j.ydbio.2015.01.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Revised: 12/15/2014] [Accepted: 01/10/2015] [Indexed: 02/06/2023]
Abstract
Elongation and invagination of epithelial tissues are fundamental developmental processes that contribute to the morphogenesis of embryonic and adult structures and are dependent on coordinated remodeling of cell-cell contacts. The morphogenesis of Drosophila leg imaginal discs depends on extensive remodeling of cell contacts and thus provides a useful system with which to investigate the underlying mechanisms. The small Rho GTPase regulator RhoGAP68F has been previously implicated in leg morphogenesis. It consists of on an N-terminal Sec14 domain and a C-terminal GAP domain. Here we examined the molecular function and role of RhoGAP68F in epithelial remodeling. We find that depletion of RhoGAP68F impairs epithelial remodeling from a pseudostratified to simple, while overexpression of RhoGAP68F causes tears of lateral cell-cell contacts and thus impairs epithelial integrity. We show that the RhoGAP68F protein localizes to Rab4 recycling endosomes and forms a complex with the Rab4 protein. The Sec14 domain is sufficient for localizing to Rab4 endosomes, while the activity of the GAP domain is dispensable. RhoGAP68F, in turn, inhibits the scission and movement of Rab4 endosomes involved in transport the adhesion proteins Fasciclin3 and E-cadherin back to cell-cell contacts. Expression of RhoGAP68F is upregulated during prepupal development suggesting that RhoGAP68F decreases the transport of key adhesion proteins to the cell surface during this developmental stage to decrease the strength of adhesive cell-cell contacts and thereby facilitate epithelial remodeling and leg morphogenesis.
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Affiliation(s)
- Beatriz Hernandez de Madrid
- Department of Developmental, Molecular and Chemical Biology, Program in Cell, Molecular and Developmental Biology, Program in Genetics, Sackler School of Graduate Biomedical Sciences, Tufts University School of Medicine, 150 Harrison Avenue, Boston, MA 02111, USA
| | - Lina Greenberg
- Department of Developmental, Molecular and Chemical Biology, Program in Cell, Molecular and Developmental Biology, Program in Genetics, Sackler School of Graduate Biomedical Sciences, Tufts University School of Medicine, 150 Harrison Avenue, Boston, MA 02111, USA
| | - Victor Hatini
- Department of Developmental, Molecular and Chemical Biology, Program in Cell, Molecular and Developmental Biology, Program in Genetics, Sackler School of Graduate Biomedical Sciences, Tufts University School of Medicine, 150 Harrison Avenue, Boston, MA 02111, USA.
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36
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Agola JO, Sivalingam D, Cimino DF, Simons PC, Buranda T, Sklar LA, Wandinger-Ness A. Quantitative bead-based flow cytometry for assaying Rab7 GTPase interaction with the Rab-interacting lysosomal protein (RILP) effector protein. Methods Mol Biol 2015; 1298:331-54. [PMID: 25800855 PMCID: PMC6033261 DOI: 10.1007/978-1-4939-2569-8_28] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/24/2023]
Abstract
Rab7 facilitates vesicular transport and delivery from early endosomes to late endosomes as well as from late endosomes to lysosomes. The role of Rab7 in vesicular transport is dependent on its interactions with effector proteins, among them Rab-interacting lysosomal protein (RILP), which aids in the recruitment of active Rab7 (GTP-bound) onto dynein-dynactin motor complexes to facilitate late endosomal transport on the cytoskeleton. Here we detail a novel bead-based flow cytometry assay to measure Rab7 interaction with the Rab-interacting lysosomal protein (RILP) effector protein and demonstrate its utility for quantitative assessment and studying drug-target interactions. The specific binding of GTP-bound Rab7 to RILP is readily demonstrated and shown to be dose-dependent and saturable enabling K d and B max determinations. Furthermore, binding is nearly instantaneous and temperature-dependent. In a novel application of the assay method, a competitive small molecule inhibitor of Rab7 nucleotide binding (CID 1067700 or ML282) is shown to inhibit the Rab7-RILP interaction. Thus, the assay is able to distinguish that the small molecule, rather than incurring the active conformation, instead 'locks' the GTPase in the inactive conformation. Together, this work demonstrates the utility of using a flow cytometry assay to quantitatively characterize protein-protein interactions involving small GTPases and which has been adapted to high-throughput screening. Further, the method provides a platform for testing small molecule effects on protein-protein interactions, which can be relevant to drug discovery and development.
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Affiliation(s)
- Jacob O Agola
- Department of Pathology, University of New Mexico School of Medicine, Albuquerque, NM, 87131, USA
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37
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McEwan DG, Popovic D, Gubas A, Terawaki S, Suzuki H, Stadel D, Coxon FP, Miranda de Stegmann D, Bhogaraju S, Maddi K, Kirchof A, Gatti E, Helfrich MH, Wakatsuki S, Behrends C, Pierre P, Dikic I. PLEKHM1 regulates autophagosome-lysosome fusion through HOPS complex and LC3/GABARAP proteins. Mol Cell 2014; 57:39-54. [PMID: 25498145 DOI: 10.1016/j.molcel.2014.11.006] [Citation(s) in RCA: 398] [Impact Index Per Article: 39.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Revised: 10/06/2014] [Accepted: 11/05/2014] [Indexed: 12/24/2022]
Abstract
The lysosome is the final destination for degradation of endocytic cargo, plasma membrane constituents, and intracellular components sequestered by macroautophagy. Fusion of endosomes and autophagosomes with the lysosome depends on the GTPase Rab7 and the homotypic fusion and protein sorting (HOPS) complex, but adaptor proteins that link endocytic and autophagy pathways with lysosomes are poorly characterized. Herein, we show that Pleckstrin homology domain containing protein family member 1 (PLEKHM1) directly interacts with HOPS complex and contains a LC3-interacting region (LIR) that mediates its binding to autophagosomal membranes. Depletion of PLEKHM1 blocks lysosomal degradation of endocytic (EGFR) cargo and enhances presentation of MHC class I molecules. Moreover, genetic loss of PLEKHM1 impedes autophagy flux upon mTOR inhibition and PLEKHM1 regulates clearance of protein aggregates in an autophagy- and LIR-dependent manner. PLEKHM1 is thus a multivalent endocytic adaptor involved in the lysosome fusion events controlling selective and nonselective autophagy pathways.
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Affiliation(s)
- David G McEwan
- Institute of Biochemistry II, Goethe University School of Medicine, Theodor-Stern-Kai 7, D-60590 Frankfurt (Main), Germany
| | - Doris Popovic
- Institute of Biochemistry II, Goethe University School of Medicine, Theodor-Stern-Kai 7, D-60590 Frankfurt (Main), Germany
| | - Andrea Gubas
- Institute of Biochemistry II, Goethe University School of Medicine, Theodor-Stern-Kai 7, D-60590 Frankfurt (Main), Germany
| | - Seigo Terawaki
- Centre d'Immunologie de Marseille-Luminy, Aix-Marseille Université, UM2, 13288 Marseille, France; INSERM, U1104, 13288 Marseille, France; CNRS, UMR 7280, 13288 Marseille, France
| | - Hironori Suzuki
- Biomolecular Interaction Centre, School of Biological Sciences, University of Canterbury, Christchurch 8020, New Zealand
| | - Daniela Stadel
- Institute of Biochemistry II, Goethe University School of Medicine, Theodor-Stern-Kai 7, D-60590 Frankfurt (Main), Germany
| | - Fraser P Coxon
- Musculoskeletal Research Programme, Division of Applied Medicine, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Diana Miranda de Stegmann
- Musculoskeletal Research Programme, Division of Applied Medicine, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Sagar Bhogaraju
- Buchmann Institute for Molecular Life Sciences, Max-von-Laue-Str. 15, Goethe University 60438 Frankfurt am Main, Germany
| | - Karthik Maddi
- Buchmann Institute for Molecular Life Sciences, Max-von-Laue-Str. 15, Goethe University 60438 Frankfurt am Main, Germany
| | - Anja Kirchof
- Institute of Biochemistry II, Goethe University School of Medicine, Theodor-Stern-Kai 7, D-60590 Frankfurt (Main), Germany
| | - Evelina Gatti
- Centre d'Immunologie de Marseille-Luminy, Aix-Marseille Université, UM2, 13288 Marseille, France; INSERM, U1104, 13288 Marseille, France; CNRS, UMR 7280, 13288 Marseille, France
| | - Miep H Helfrich
- Musculoskeletal Research Programme, Division of Applied Medicine, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Soichi Wakatsuki
- Structural Biology Research Center, Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 305-0801, Japan
| | - Christian Behrends
- Institute of Biochemistry II, Goethe University School of Medicine, Theodor-Stern-Kai 7, D-60590 Frankfurt (Main), Germany
| | - Philippe Pierre
- Centre d'Immunologie de Marseille-Luminy, Aix-Marseille Université, UM2, 13288 Marseille, France; INSERM, U1104, 13288 Marseille, France; CNRS, UMR 7280, 13288 Marseille, France
| | - Ivan Dikic
- Institute of Biochemistry II, Goethe University School of Medicine, Theodor-Stern-Kai 7, D-60590 Frankfurt (Main), Germany; Buchmann Institute for Molecular Life Sciences, Max-von-Laue-Str. 15, Goethe University 60438 Frankfurt am Main, Germany; University of Split, School of Medicine, Department of Immunology and Medical Genetics, Soltanska 2, 21 000 Split, Croatia.
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Septin6 and Septin7 GTP binding proteins regulate AP-3- and ESCRT-dependent multivesicular body biogenesis. PLoS One 2014; 9:e109372. [PMID: 25380047 PMCID: PMC4224394 DOI: 10.1371/journal.pone.0109372] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Accepted: 09/04/2014] [Indexed: 11/19/2022] Open
Abstract
Septins (SEPTs) form a family of GTP-binding proteins implicated in cytoskeleton and membrane organization, cell division and host/pathogen interactions. The precise function of many family members remains elusive. We show that SEPT6 and SEPT7 complexes bound to F-actin regulate protein sorting during multivesicular body (MVB) biogenesis. These complexes bind AP-3, an adapter complex sorting cargos destined to remain in outer membranes of maturing endosomes, modulate AP-3 membrane interactions and the motility of AP-3-positive endosomes. These SEPT-AP interactions also influence the membrane interaction of ESCRT (endosomal-sorting complex required for transport)-I, which selects ubiquitinated cargos for degradation inside MVBs. Whereas our findings demonstrate that SEPT6 and SEPT7 function in the spatial, temporal organization of AP-3- and ESCRT-coated membrane domains, they uncover an unsuspected coordination of these sorting machineries during MVB biogenesis. This requires the E3 ubiquitin ligase LRSAM1, an AP-3 interactor regulating ESCRT-I sorting activity and whose mutations are linked with Charcot-Marie-Tooth neuropathies.
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Asmat TM, Agarwal V, Saleh M, Hammerschmidt S. Endocytosis of Streptococcus pneumoniae via the polymeric immunoglobulin receptor of epithelial cells relies on clathrin and caveolin dependent mechanisms. Int J Med Microbiol 2014; 304:1233-46. [PMID: 25455218 DOI: 10.1016/j.ijmm.2014.10.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Revised: 09/18/2014] [Accepted: 10/05/2014] [Indexed: 12/17/2022] Open
Abstract
Colonization of Streptococcus pneumoniae (pneumococci) is a prerequisite for bacterial dissemination and their capability to enter the bloodstream. Pneumococci have evolved various successful strategies to colonize the mucosal epithelial barrier of humans. A pivotal mechanism of host cell invasion implicated with invasive diseases is promoted by the interaction of pneumococcal PspC with the polymeric Ig-receptor (pIgR). However, the mechanism(s) of pneumococcal endocytosis and the intracellular route of pneumococci upon uptake by the PspC-pIgR-interaction are not known. Here, we demonstrate by using a combination of pharmacological inhibitors and genetics interference approaches the involvement of active dynamin-dependent caveolae and clathrin-coated vesicles for pneumococcal uptake via the PspC-pIgR mechanism. Depleting cholesterol from host cell membranes and disruption of lipid microdomains impaired pneumococcal internalization. Moreover, chemical inhibition of clathrin or functional inactivation of dynamin, caveolae or clathrin by RNA interference significantly affected pneumococcal internalization suggesting that clathrin-mediated endocytosis (CME) and caveolae are involved in the bacterial uptake process. Confocal fluorescence microscopy of pIgR-expressing epithelial cells infected with pneumococci or heterologous Lactococcus lactis expressing PspC demonstrated bacterial co-localization with fluorescent-tagged clathrin and early as well as recycling or late endosomal markers such as Lamp1, Rab5, Rab4, and Rab7, respectively. In conclusion these data suggest that PspC-promoted uptake is mediated by both CME and caveolae. After endocytosis pneumococci are routed via the endocytic pathway into early endosomes and are then sorted into recycling or late endosomes, which can result in pneumococcal killing in phagolysosomes or transcytosis via recycling endosomes.
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Affiliation(s)
- Tauseef M Asmat
- Department Genetics of Microorganisms, Interfaculty Institute for Genetics and Functional Genomics, Ernst-Moritz-Arndt Universität Greifswald, Friedrich-Ludwig-Jahn-Strasse 15a, D-17487 Greifswald, Germany; Pediatric Infectious Diseases, Department of Pediatrics, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Vaibhav Agarwal
- Department Genetics of Microorganisms, Interfaculty Institute for Genetics and Functional Genomics, Ernst-Moritz-Arndt Universität Greifswald, Friedrich-Ludwig-Jahn-Strasse 15a, D-17487 Greifswald, Germany; Department of Laboratory Medicine, Medical Protein Chemistry, Malmö University Hospital, Lund University, Malmö, Sweden
| | - Malek Saleh
- Department Genetics of Microorganisms, Interfaculty Institute for Genetics and Functional Genomics, Ernst-Moritz-Arndt Universität Greifswald, Friedrich-Ludwig-Jahn-Strasse 15a, D-17487 Greifswald, Germany
| | - Sven Hammerschmidt
- Department Genetics of Microorganisms, Interfaculty Institute for Genetics and Functional Genomics, Ernst-Moritz-Arndt Universität Greifswald, Friedrich-Ludwig-Jahn-Strasse 15a, D-17487 Greifswald, Germany.
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Miura E, Hasegawa T, Konno M, Suzuki M, Sugeno N, Fujikake N, Geisler S, Tabuchi M, Oshima R, Kikuchi A, Baba T, Wada K, Nagai Y, Takeda A, Aoki M. VPS35 dysfunction impairs lysosomal degradation of α-synuclein and exacerbates neurotoxicity in a Drosophila model of Parkinson's disease. Neurobiol Dis 2014; 71:1-13. [PMID: 25107340 DOI: 10.1016/j.nbd.2014.07.014] [Citation(s) in RCA: 144] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2014] [Revised: 07/07/2014] [Accepted: 07/28/2014] [Indexed: 12/31/2022] Open
Abstract
Mutations in vacuolar protein sorting 35 (VPS35) have been linked to familial Parkinson's disease (PD). VPS35, a component of the retromer, mediates the retrograde transport of cargo from the endosome to the trans-Golgi network. Here we showed that retromer depletion increases the lysosomal turnover of the mannose 6-phosphate receptor, thereby affecting the trafficking of cathepsin D (CTSD), a lysosome protease involved in α-synuclein (αSYN) degradation. VPS35 knockdown perturbed the maturation step of CTSD in parallel with the accumulation of αSYN in the lysosomes. Furthermore, we found that the knockdown of Drosophila VPS35 not only induced the accumulation of the detergent-insoluble αSYN species in the brain but also exacerbated both locomotor impairments and mild compound eye disorganization and interommatidial bristle loss in flies expressing human αSYN. These findings indicate that the retromer may play a crucial role in αSYN degradation by modulating the maturation of CTSD and might thereby contribute to the pathogenesis of the disease.
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Affiliation(s)
- Emiko Miura
- Division of Neurology, Department of Neuroscience & Sensory Organs, Tohoku University Graduate School of Medicine, Sendai 980-8574, Japan
| | - Takafumi Hasegawa
- Division of Neurology, Department of Neuroscience & Sensory Organs, Tohoku University Graduate School of Medicine, Sendai 980-8574, Japan.
| | - Masatoshi Konno
- Division of Neurology, Department of Neuroscience & Sensory Organs, Tohoku University Graduate School of Medicine, Sendai 980-8574, Japan; Department of Degenerative Neurological Diseases, National Institute of Neuroscience, National Center of Neurology and Psychiatry (NCNP), Kodaira 187-8502, Japan
| | - Mari Suzuki
- Department of Degenerative Neurological Diseases, National Institute of Neuroscience, National Center of Neurology and Psychiatry (NCNP), Kodaira 187-8502, Japan
| | - Naoto Sugeno
- Division of Neurology, Department of Neuroscience & Sensory Organs, Tohoku University Graduate School of Medicine, Sendai 980-8574, Japan
| | - Nobuhiro Fujikake
- Department of Degenerative Neurological Diseases, National Institute of Neuroscience, National Center of Neurology and Psychiatry (NCNP), Kodaira 187-8502, Japan
| | - Sven Geisler
- Laboratory of Functional Neurogenetics, Department for Neurodegenerative Diseases, Hertie Institute for Clinical Brain Research, University of Tübingen, German Centre for Neurodegenerative Diseases (DZNE), 72076 Tübingen, Germany
| | - Mitsuaki Tabuchi
- Laboratory of Applied Molecular Cell Biology, Faculty of Agriculture, Kagawa University, Kagawa 761-0795, Japan
| | - Ryuji Oshima
- Division of Neurology, Department of Neuroscience & Sensory Organs, Tohoku University Graduate School of Medicine, Sendai 980-8574, Japan
| | - Akio Kikuchi
- Division of Neurology, Department of Neuroscience & Sensory Organs, Tohoku University Graduate School of Medicine, Sendai 980-8574, Japan
| | - Toru Baba
- Division of Neurology, Department of Neuroscience & Sensory Organs, Tohoku University Graduate School of Medicine, Sendai 980-8574, Japan
| | - Keiji Wada
- Department of Degenerative Neurological Diseases, National Institute of Neuroscience, National Center of Neurology and Psychiatry (NCNP), Kodaira 187-8502, Japan
| | - Yoshitaka Nagai
- Department of Degenerative Neurological Diseases, National Institute of Neuroscience, National Center of Neurology and Psychiatry (NCNP), Kodaira 187-8502, Japan
| | - Atsushi Takeda
- Division of Neurology, Department of Neuroscience & Sensory Organs, Tohoku University Graduate School of Medicine, Sendai 980-8574, Japan; Department of Neurology, National Hospital Organization Sendai-Nishitaga Hospital, Sendai 982-8555, Japan
| | - Masashi Aoki
- Division of Neurology, Department of Neuroscience & Sensory Organs, Tohoku University Graduate School of Medicine, Sendai 980-8574, Japan
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Liu Y, Kim YJ, Ji M, Fang J, Siriwon N, Zhang LI, Wang P. Enhancing gene delivery of adeno-associated viruses by cell-permeable peptides. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2014; 1:12. [PMID: 26015948 PMCID: PMC4365833 DOI: 10.1038/mtm.2013.12] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Accepted: 12/08/2013] [Indexed: 12/21/2022]
Abstract
Adeno-associated virus type 2 (AAV2) is considered a promising gene delivery vector and has been extensively applied in several disease models; however, inefficient transduction in various cells and tissues has limited its widespread application in many areas of gene therapy. In this study, we have developed a general, but efficient, strategy to enhance viral transduction, both in vitro and in vivo, by incubating viral particles with cell-permeable peptides (CPPs). We show that CPPs increase internalization of viral particles into cells by facilitating both energy-independent and energy-dependent endocytosis. Moreover, CPPs can significantly enhance the endosomal escape process of viral particles, thus enhancing viral transduction to those cells that have exhibited very low permissiveness to AAV2 infection as a result of impaired intracellular viral processing. We also demonstrated that this approach could be applicable to other AAV serotypes. Thus, the membrane-penetrating ability of CPPs enables us to generate an efficient method for enhanced gene delivery of AAV vectors, potentially facilitating its applicability to human gene therapy.
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Affiliation(s)
- Yarong Liu
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California , Los Angeles, California, USA
| | - Young Joo Kim
- Department of Physiology and Biophysics, University of Southern California , Los Angeles, California, USA
| | - Man Ji
- Department of Biochemistry and Molecular Biology, University of Southern California , Los Angeles, California, USA
| | - Jinxu Fang
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California , Los Angeles, California, USA
| | - Natnaree Siriwon
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California , Los Angeles, California, USA
| | - Li I Zhang
- Department of Physiology and Biophysics, University of Southern California , Los Angeles, California, USA
| | - Pin Wang
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California , Los Angeles, California, USA ; Department of Biomedical Engineering, University of Southern California , Los Angeles, California, USA ; Department of Pharmacology and Pharmaceutical Sciences, University of Southern California , Los Angeles, California, USA
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42
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Nakamura K, Yamanouchi K, Nishihara M. Secreted protein acidic and rich in cysteine internalization and its age-related alterations in skeletal muscle progenitor cells. Aging Cell 2014; 13:175-84. [PMID: 24245505 PMCID: PMC4326877 DOI: 10.1111/acel.12168] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/27/2013] [Indexed: 01/06/2023] Open
Abstract
Aging causes phenotypic changes in skeletal muscle progenitor cells (Skm-PCs), such as reduced myogenesis and increased adipogenesis due to alterations in their environment or niche. Secreted protein acidic and rich in cysteine (SPARC), which is secreted into the niche of Skm-PCs, inhibits adipogenesis and promotes myogenesis. We have previously reported that Skm-PC responsiveness to SPARC declines with age, although the mechanism underlying this decline is unknown. In this study, we found that SPARC is internalized by Skm-PCs and that this uptake increases with age. Internalization is dependent on integrin-α5, a cell surface SPARC-binding molecule, and clathrin-mediated endocytosis. We also demonstrated that internalized SPARC is transported to Rab7-positive endosomes. Skm-PCs from old rats exhibited increased clathrin expression and decreased Rab7 expression exclusively in MyoD-negative cells. In loss-of-function analyses, clathrin knockdown increased the anti-adipogenic effect of SPARC, whereas Rab7 knockdown reduced it, indicating that alterations in SPARC internalization may mediate the age-related decline in its anti-adipogenic effect. These results provide insights into age-related SPARC resistance in Skm-PCs, which may lead to sarcopenia.
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Affiliation(s)
- Katsuyuki Nakamura
- Department of Veterinary Physiology; Graduate School of Agricultural and Life Sciences; The University of Tokyo; 1-1-1 Yayoi Bunkyo-ku Tokyo 113-8657 Japan
| | - Keitaro Yamanouchi
- Department of Veterinary Physiology; Graduate School of Agricultural and Life Sciences; The University of Tokyo; 1-1-1 Yayoi Bunkyo-ku Tokyo 113-8657 Japan
| | - Masugi Nishihara
- Department of Veterinary Physiology; Graduate School of Agricultural and Life Sciences; The University of Tokyo; 1-1-1 Yayoi Bunkyo-ku Tokyo 113-8657 Japan
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43
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Girard E, Chmiest D, Fournier N, Johannes L, Paul JL, Vedie B, Lamaze C. Rab7 is functionally required for selective cargo sorting at the early endosome. Traffic 2014; 15:309-26. [PMID: 24329906 DOI: 10.1111/tra.12143] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Revised: 12/04/2013] [Accepted: 12/10/2013] [Indexed: 12/26/2022]
Abstract
The small GTPases of the Rab family act as a molecular switch regulating various aspects of membrane trafficking through the selective recruitment of effector proteins. Whereas Rab7 has been classically involved in the regulation of transport within the endolysosomal network, persistent controversy remains as to whether Rab7 also plays a role in earlier steps of endosomal trafficking. In this study, we show that Rab7 depletion or inactivation results in enlargement of both early and late endosomes. Rab7 depletion led to the retention of a significant fraction of internalized low-density lipoproteins (LDL) mainly in enlarged early endosomes (EE). As a result, LDL processing and the transcriptional regulation of sterol-sensitive genes were impaired. We found that Rab7 activity was also required for the sorting of the mannose-6-phosphate receptor, the interferon alpha-receptor and the Shiga toxin B-subunit. In contrast, epidermal growth factor (EGF) sorting at the EE or the recycling of transferrin and LDL-R were not affected by Rab7 depletion. Our findings demonstrate that in addition to regulating late endosomes (LE) to lysosomes transport, Rab7 plays a functional role in the selective sorting of distinct cargos at the EE and that the Rab5 to Rab7 exchange occurs early in the endosomal maturation process.
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Affiliation(s)
- Emmanuelle Girard
- AP-HP (Assistance Publique - Hôpitaux de Paris), Hôpital Européen Georges Pompidou, Service de Biochimie, 75015, Paris, France; Université Paris-Sud, EA 4529, UFR de Pharmacie, 92296, Châtenay-Malabry, France; CNRS UMR144, 75248 Paris cedex 05, France; Institut Curie, Centre de Recherche, Laboratoire Trafic, Signalisation et Ciblage Intracellulaires, 75248, Paris Cedex 05, France
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44
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Schwenk BM, Lang CM, Hogl S, Tahirovic S, Orozco D, Rentzsch K, Lichtenthaler SF, Hoogenraad CC, Capell A, Haass C, Edbauer D. The FTLD risk factor TMEM106B and MAP6 control dendritic trafficking of lysosomes. EMBO J 2013; 33:450-67. [PMID: 24357581 DOI: 10.1002/embj.201385857] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
TMEM106B is a major risk factor for frontotemporal lobar degeneration with TDP-43 pathology. TMEM106B localizes to lysosomes, but its function remains unclear. We show that TMEM106B knockdown in primary neurons affects lysosomal trafficking and blunts dendritic arborization. We identify microtubule-associated protein 6 (MAP6) as novel interacting protein for TMEM106B. MAP6 over-expression inhibits dendritic branching similar to TMEM106B knockdown. MAP6 knockdown fully rescues the dendritic phenotype of TMEM106B knockdown, supporting a functional interaction between TMEM106B and MAP6. Live imaging reveals that TMEM106B knockdown and MAP6 overexpression strongly increase retrograde transport of lysosomes in dendrites. Downregulation of MAP6 in TMEM106B knockdown neurons restores the balance of anterograde and retrograde lysosomal transport and thereby prevents loss of dendrites. To strengthen the link, we enhanced anterograde lysosomal transport by expressing dominant-negative Rab7-interacting lysosomal protein (RILP), which also rescues the dendrite loss in TMEM106B knockdown neurons. Thus, TMEM106B/MAP6 interaction is crucial for controlling dendritic trafficking of lysosomes, presumably by acting as a molecular brake for retrograde transport. Lysosomal misrouting may promote neurodegeneration in patients with TMEM106B risk variants.
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45
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c-Abl and Arg induce cathepsin-mediated lysosomal degradation of the NM23-H1 metastasis suppressor in invasive cancer. Oncogene 2013; 33:4508-4520. [PMID: 24096484 PMCID: PMC3979510 DOI: 10.1038/onc.2013.399] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Revised: 07/22/2013] [Accepted: 08/06/2013] [Indexed: 02/08/2023]
Abstract
Metastasis suppressors comprise a growing class of genes whose downregulation triggers metastatic progression. In contrast to tumor suppressors, metastasis suppressors are rarely mutated or deleted, and little is known regarding the mechanisms by which their expression is downregulated. Here, we demonstrate that the metastasis suppressor, NM23-H1, is degraded by lysosomal cysteine cathepsins (L,B), which directly cleave NM23-H1. In addition, activation of c-Abl and Arg oncoproteins induces NM23-H1 degradation in invasive cancer cells by increasing cysteine cathepsin transcription and activation. Moreover, c-Abl activates cathepsins by promoting endosome maturation, which facilitates trafficking of NM23-H1 to the lysosome where it is degraded. Importantly, the invasion- and metastasis-promoting activity of c-Abl/Arg is dependent on their ability to induce NM23-H1 degradation, and the pathway is clinically relevant as c-Abl/Arg activity and NM23-H1 expression are inversely correlated in primary breast cancers and melanomas. Thus, we demonstrate a novel mechanism by which cathepsin expression is upregulated in cancer cells (via Abl kinases). We also identify a novel role for intracellular cathepsins in invasion and metastasis (degradation of a metastasis suppressor). Finally, we identify novel crosstalk between oncogenic and metastasis suppressor pathways, thereby providing mechanistic insight into the process of NM23-H1 loss, which may pave the way for new strategies to restore NM23-H1 expression and block metastatic progression.
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46
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Abstract
The autophagic degradation pathway is a powerful tool in the host cell arsenal against cytosolic pathogens. Contents trapped inside cytosolic vesicles, termed autophagosomes, are delivered to the lysosome for degradation. In spite of the degradative nature of the pathway, some pathogens are able to subvert autophagy for their benefit. In many cases, these pathogens have developed strategies to induce the autophagic signaling pathway while inhibiting the associated degradation activity. One surprising finding from recent literature is that some viruses do not impede degradation but instead promote the generation of degradative autolysosomes, which are the endpoint compartments of autophagy. Dengue virus, poliovirus, and hepatitis C virus, all positive-strand RNA viruses, utilize the maturation of autophagosomes into acidic and ultimately degradative compartments to promote their replication. While the benefits that each virus reaps from autophagosome maturation are unique, the parallels between the viruses indicate a complex relationship between cytosolic viruses and host cell degradation vesicles.
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47
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Steele DF, Fedida D. Cytoskeletal roles in cardiac ion channel expression. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1838:665-73. [PMID: 23680626 DOI: 10.1016/j.bbamem.2013.05.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Revised: 05/01/2013] [Accepted: 05/06/2013] [Indexed: 11/25/2022]
Abstract
The cytoskeleton and cardiac ion channel expression are closely linked. From the time that newly synthesized channels exit the endoplasmic reticulum, they are either traveling along the microtubule or actin cytoskeletons or likely anchored in the plasma membrane or in internal vesicular pools by those scaffolds. Molecular motors, small GTPases and even the dynamics of the cytoskeletons themselves influence the trafficking and expression of the channels. In some cases, the functioning of the channels themselves has profound influences on the cytoskeleton. Here we provide an overview of the current state of knowledge on the involvement of the actin and microtubule cytoskeletons in the trafficking, targeting and expression of cardiac ion channels and a few channels expressed elsewhere. We highlight, also, some of the many questions that remain about these processes. This article is part of a Special Issue entitled: Reciprocal influences between cell cytoskeleton and membrane channels, receptors and transporters. Guest Editor: Jean Claude Hervé.
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Affiliation(s)
- David F Steele
- Dept. of Anesthesiology, Pharmacology and Therapeutics, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
| | - David Fedida
- Dept. of Anesthesiology, Pharmacology and Therapeutics, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada.
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48
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Jia F, Li Y, Huang Y, Chen T, Li S, Xu Y, Wu Z, Li X, Yu X. Molecular characterization and expression of Rab7 from Clonorchis sinensis and its potential role in autophagy. Parasitol Res 2013; 112:2461-7. [PMID: 23609597 DOI: 10.1007/s00436-013-3409-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Accepted: 03/21/2013] [Indexed: 10/26/2022]
Abstract
Accumulating evidences suggest that Rab7 GTPase is important for the normal progression of autophagy. However, the role of Rab7 GTPase in regulation of autophagy in Clonorchis sinensis is not known. In this study, a gene encoding Rab7 was isolated from C. sinensis adult cDNA. Recombinant CsRab7 was expressed and purified from Escherichia coli. CsRab7 transcripts were detected in the cDNA of adult worm, metacercaria, cercaria, and egg of C. sinensis, and were highly expressed in the metacercaria. Immunohistochemical localization results revealed that CsRab7 was specifically deposited on the vitellarium and eggs of adult worm. Furthermore, EGFP signal of CsRab7WT and the active mutant CsRab7Q67L were associated with autophagic vesicles in transiently transfected 293T cells. It is concluded from the present study that CsRab7 GTPase possibly contributes to the development of C. sinensis and that the autophagy pathway could be an important site of action with respect to the developmental role of CsRab7 in C. sinensis.
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Affiliation(s)
- Feifei Jia
- Department of Parasitology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
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Maturation of autophagosomes and endosomes: a key role for Rab7. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2012; 1833:503-10. [PMID: 23220125 DOI: 10.1016/j.bbamcr.2012.11.018] [Citation(s) in RCA: 285] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2012] [Revised: 11/21/2012] [Accepted: 11/22/2012] [Indexed: 01/24/2023]
Abstract
Macroautophagy is an important route in cellular maintenance, in the breakdown and reuse of intracellular materials. It is closely related to endocytosis, the means by which the cell can absorb extracellular material, as both macroautophagy and endocytosis have converging steps and common participating molecules. The point where autophagosomes and endosomes fuse with lysosomes to permit for the final degradation of their contents is important. One of the most substantial molecules in the maturation of autophagosomes/endosomes is Rab7, a member of small GTPases. Rab7 designates the maturation of endosomes and also autophagosomes, directing the trafficking of cargos along microtubules, and finally, participating in the fusion step with lysosomes. Rab7 is an effective multifunctional regulator of autophagy and endocytosis. Since many aggregation-based diseases, e.g. age-related macular degeneration of the eye (AMD) and Alzheimer's disease are due of malfunctioning in the autophagic process, the management of Rab7 activity might hold potential as a therapeutic target against these diseases.
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The balance between receptor recycling and trafficking toward lysosomes determines synaptic strength during long-term depression. J Neurosci 2012; 32:13200-5. [PMID: 22993436 DOI: 10.1523/jneurosci.0061-12.2012] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The strength of excitatory synaptic transmission depends partly on the number of AMPA receptors (AMPARs) at the postsynaptic surface and, thus, can be modulated by membrane trafficking events. These processes are critical for some forms of synaptic plasticity, such as long-term potentiation and long-term depression (LTD). In the case of LTD, AMPARs are internalized and dephosphorylated in response to NMDA receptor activation. However, the fate of the internalized receptors upon LTD induction and its relevance for synaptic function is still a matter of debate. Here we examined the functional contribution of receptor recycling versus degradation for LTD in rat hippocampal slices, and their correlation with receptor dephosphorylation. We observed that GluA1 undergoes sequential dephosphorylation and degradation in lysosomes after LTD induction. However, this degradation does not have functional consequences for the regulation of synaptic strength, and therefore, for the expression of LTD. In contrast, the partition of internalized AMPARs between Rab7-dependent trafficking (toward lysosomes) or Rab11-dependent endosomes (recycling back toward synapses) is the key factor determining the extent of synaptic depression upon LTD induction. This sorting decision is related to the phosphorylation status of GluA1 Ser845, the dephosphorylated receptors being those preferentially targeted for lysosomal degradation. Altogether, these new data contribute to clarify the fate of AMPARs during LTD and emphasize the importance of membrane sorting decisions to determine the outcome of synaptic plasticity.
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