1
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Wilczak M, Surman M, Jankowska U, Skupien-Rabian B, Przybyło M. MGAT3 and MGAT5 overexpression alters the protein cargo of extracellular vesicles released by metastatic melanoma cells. Biochem Biophys Res Commun 2025; 762:151749. [PMID: 40199132 DOI: 10.1016/j.bbrc.2025.151749] [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: 12/12/2024] [Revised: 03/25/2025] [Accepted: 04/01/2025] [Indexed: 04/10/2025]
Abstract
Extracellular vesicles (EVs) are potential non-invasive diagnostic, prognostic and therapeutic tools. Additionally, they are important contributors to tumorigenesis. Glycosylation has been found to modulate the composition of the EV proteome. Increased amounts of β1,6-branched N-glycans, synthesized by N-acetylglucosaminyltransferase V (GnT-V), are most commonly observed in melanoma and are associated with decreased cell adhesion and increased metastasis. The opposite effect is caused by the addition of bisecting GlcNAc by N-acetylglucosaminyltransferase III (GnT-III). To date, the impact of these enzymes on EV cargo in melanoma remains unexplored. Flow cytometry was used to study the surface glycosylation of genetic variants of WM266-4 melanoma cells with induced overexpression of GnT-III or GnT-V encoding genes (MGAT3 or MGAT5) and EVs released by these cells. LC-MS/MS proteomics was applied to analyze the effect of altered glycosylation on the proteome of released EVs, followed by detailed bioinformatic analysis. Flow cytometry analysis revealed dynamic changes in the surface glycosylation of EVs derived from melanoma cells overexpressing MGAT3 or MGAT5. Induced overexpression of MGAT3 or MGAT5 also caused significant changes in the proteome of EVs. The proteomic analysis identified a total of 1770 microvesicular and 704 exosomal proteins that play different roles in melanoma progression, including those with established diagnostic/prognostic potential and those closely associated with melanoma onset. Proteomic profiling of EVs derived from cells overexpressing MGAT3 and MGAT5 revealed functional changes in EV protein content driven by glycosylation modifications. The study presented a potential multifaced application of melanoma-derived EVs for diagnostic and prognostic purposes.
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Affiliation(s)
- Magdalena Wilczak
- Department of Glycoconjugate Biochemistry, Institute of Zoology and Biomedical Research, Faculty of Biology, Jagiellonian University, 30-387, Krakow, Poland; Doctoral School of Exact and Natural Sciences, Jagiellonian University, 30-348, Krakow, Poland.
| | - Magdalena Surman
- Department of Glycoconjugate Biochemistry, Institute of Zoology and Biomedical Research, Faculty of Biology, Jagiellonian University, 30-387, Krakow, Poland.
| | - Urszula Jankowska
- Proteomics and Mass Spectrometry Core Facility, Malopolska Centre of Biotechnology, Jagiellonian University, 30-387, Krakow, Poland.
| | - Bozena Skupien-Rabian
- Proteomics and Mass Spectrometry Core Facility, Malopolska Centre of Biotechnology, Jagiellonian University, 30-387, Krakow, Poland.
| | - Małgorzata Przybyło
- Department of Glycoconjugate Biochemistry, Institute of Zoology and Biomedical Research, Faculty of Biology, Jagiellonian University, 30-387, Krakow, Poland.
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Chandra M, Kendall AK, Ford MGJ, Jackson LP. VARP binds SNX27 to promote endosomal supercomplex formation on membranes. SCIENCE ADVANCES 2025; 11:eadr9340. [PMID: 39937906 PMCID: PMC11817943 DOI: 10.1126/sciadv.adr9340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2024] [Accepted: 01/09/2025] [Indexed: 02/14/2025]
Abstract
Endosomes are vital cellular hubs for sorting protein cargoes. Retromer (VPS26/VPS35/VPS29) binds multiple sorting nexin (SNX) proteins on endosomal membranes, but assembly mechanisms of metazoan SNX/Retromer complexes remain elusive. We combine biochemical and biophysical approaches with AlphaFold modeling to identify a previously unidentified direct interaction between SNX27 and VARP. A full biochemical reconstitution system using purified proteins systematically tests how and when coats are recruited to membranes to generate tubules. We demonstrate and measure how specific combinations of Retromer with SNX27, ESCPE-1 (SNX2/SNX6), or both complexes, remodel membranes containing physiological cargo and phospholipids. SNX27, alone and with Retromer, remodels membranes with PI(3)P and PDZbm cargo. ESCPE-1 deforms membranes with bis-phosphoinositides and CI-MPR cargo but surprisingly does not recruit Retromer. VARP co-immunoprecipitates all coat components in cells and is required to reconstitute a proposed endosomal "supercomplex" (SNX27, ESCPE-1, and Retromer) in vitro. These data suggest VARP regulates metazoan endosomal coat assembly to promote cargo sorting out of endosomes.
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Affiliation(s)
- Mintu Chandra
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
- Center for Structural Biology, Vanderbilt University, Nashville, TN, USA
| | - Amy K. Kendall
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
- Center for Structural Biology, Vanderbilt University, Nashville, TN, USA
| | - Marijn G. J. Ford
- Department of Biochemistry, Vanderbilt University, Nashville, TN, USA
| | - Lauren P. Jackson
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
- Center for Structural Biology, Vanderbilt University, Nashville, TN, USA
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA, USA
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3
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Chandra M, Kendall AK, Ford MGJ, Jackson LP. VARP binds SNX27 to promote endosomal supercomplex formation on membranes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.11.603126. [PMID: 39026782 PMCID: PMC11257539 DOI: 10.1101/2024.07.11.603126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/20/2024]
Abstract
Multiple essential membrane trafficking pathways converge at endosomes to maintain cellular homeostasis by sorting critical transmembrane cargo proteins to the plasma membrane or the trans-Golgi network (TGN). The Retromer heterotrimer (VPS26/VPS35/VPS29 subunits) binds multiple sorting nexin (SNX) proteins on endosomal membranes, but molecular mechanisms regarding formation and regulation of metazoan SNX/Retromer complexes have been elusive. Here, we combine biochemical and biophysical approaches with AlphaFold2 Multimer modeling to identify a direct interaction between the VARP N-terminus and SNX27 PDZ domain. VARP and SNX27 interact with high nanomolar affinity using the binding pocket established for PDZ binding motif (PDZbm) cargo. Specific point mutations in VARP abrogate the interaction in vitro. We further establish a full biochemical reconstitution system using purified mammalian proteins to directly and systematically test whether multiple endosomal coat complexes are recruited to membranes to generate tubules. We successfully use purified coat components to demonstrate which combinations of Retromer with SNX27, ESCPE-1 (SNX2/SNX6), or both complexes can remodel membranes containing physiological cargo motifs and phospholipid composition. SNX27, alone and with Retromer, induces tubule formation in the presence of PI(3)P and PDZ cargo motifs. ESCPE-1 deforms membranes enriched with Folch I and CI-MPR cargo motifs, but surprisingly does not recruit Retromer. Finally, we find VARP is required to reconstitute a proposed endosomal "supercomplex" containing SNX27, ESCPE-1, and Retromer on PI(3)P-enriched membranes. These data suggest VARP functions as a key regulator in metazoans to promote cargo sorting out of endosomes.
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Affiliation(s)
- Mintu Chandra
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
- Center for Structural Biology, Vanderbilt University, Nashville, TN, USA
| | - Amy K Kendall
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
- Center for Structural Biology, Vanderbilt University, Nashville, TN, USA
| | - Marijn G J Ford
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Lauren P Jackson
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
- Center for Structural Biology, Vanderbilt University, Nashville, TN, USA
- Department of Biochemistry, Vanderbilt University, Nashville, TN, USA
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4
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Tziouvara O, Petsana M, Kourounis D, Papadaki A, Basdra E, Braliou GG, Boleti H. Characterization of the First Secreted Sorting Nexin Identified in the Leishmania Protists. Int J Mol Sci 2024; 25:4095. [PMID: 38612903 PMCID: PMC11012638 DOI: 10.3390/ijms25074095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Revised: 03/19/2024] [Accepted: 03/19/2024] [Indexed: 04/14/2024] Open
Abstract
Proteins of the sorting nexin (SNX) family present a modular structural architecture with a phox homology (PX) phosphoinositide (PI)-binding domain and additional PX structural domains, conferring to them a wide variety of vital eukaryotic cell's functions, from signal transduction to membrane deformation and cargo binding. Although SNXs are well studied in human and yeasts, they are poorly investigated in protists. Herein, is presented the characterization of the first SNX identified in Leishmania protozoan parasites encoded by the LdBPK_352470 gene. In silico secondary and tertiary structure prediction revealed a PX domain on the N-terminal half and a Bin/amphiphysin/Rvs (BAR) domain on the C-terminal half of this protein, with these features classifying it in the SNX-BAR subfamily of SNXs. We named the LdBPK_352470.1 gene product LdSNXi, as it is the first SNX identified in Leishmania (L.) donovani. Its expression was confirmed in L. donovani promastigotes under different cell cycle phases, and it was shown to be secreted in the extracellular medium. Using an in vitro lipid binding assay, it was demonstrated that recombinant (r) LdSNXi (rGST-LdSNXi) tagged with glutathione-S-transferase (GST) binds to the PtdIns3P and PtdIns4P PIs. Using a specific a-LdSNXi antibody and immunofluorescence confocal microscopy, the intracellular localization of endogenous LdSNXi was analyzed in L. donovani promastigotes and axenic amastigotes. Additionally, rLdSNXi tagged with enhanced green fluorescent protein (rLdSNXi-EGFP) was heterologously expressed in transfected HeLa cells and its localization was examined. All observed localizations suggest functions compatible with the postulated SNX identity of LdSNXi. Sequence, structure, and evolutionary analysis revealed high homology between LdSNXi and the human SNX2, while the investigation of protein-protein interactions based on STRING (v.11.5) predicted putative molecular partners of LdSNXi in Leishmania.
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Affiliation(s)
- Olympia Tziouvara
- Intracellular Parasitism Group, Department of Microbiology, Hellenic Pasteur Institute, 11521 Athens, Greece; (O.T.); (M.P.); (D.K.); (A.P.)
- Department of Biological Chemistry, Medical School, National and Kapodistrian University of Athens, 11527 Athens, Greece;
| | - Marina Petsana
- Intracellular Parasitism Group, Department of Microbiology, Hellenic Pasteur Institute, 11521 Athens, Greece; (O.T.); (M.P.); (D.K.); (A.P.)
- Department of Computer Science and Biomedical Informatics, University of Thessaly, 2–4 Papasiopoulou Str., 35131 Lamia, Greece;
| | - Drosos Kourounis
- Intracellular Parasitism Group, Department of Microbiology, Hellenic Pasteur Institute, 11521 Athens, Greece; (O.T.); (M.P.); (D.K.); (A.P.)
| | - Amalia Papadaki
- Intracellular Parasitism Group, Department of Microbiology, Hellenic Pasteur Institute, 11521 Athens, Greece; (O.T.); (M.P.); (D.K.); (A.P.)
| | - Efthimia Basdra
- Department of Biological Chemistry, Medical School, National and Kapodistrian University of Athens, 11527 Athens, Greece;
| | - Georgia G. Braliou
- Department of Computer Science and Biomedical Informatics, University of Thessaly, 2–4 Papasiopoulou Str., 35131 Lamia, Greece;
| | - Haralabia Boleti
- Intracellular Parasitism Group, Department of Microbiology, Hellenic Pasteur Institute, 11521 Athens, Greece; (O.T.); (M.P.); (D.K.); (A.P.)
- Bioimaging Unit, Hellenic Pasteur Institute, 11521 Athens, Greece
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Carosi JM, Denton D, Kumar S, Sargeant TJ. Receptor Recycling by Retromer. Mol Cell Biol 2023; 43:317-334. [PMID: 37350516 PMCID: PMC10348044 DOI: 10.1080/10985549.2023.2222053] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 06/01/2023] [Indexed: 06/24/2023] Open
Abstract
The highly conserved retromer complex controls the fate of hundreds of receptors that pass through the endolysosomal system and is a central regulatory node for diverse metabolic programs. More than 20 years ago, retromer was discovered as an essential regulator of endosome-to-Golgi transport in yeast; since then, significant progress has been made to characterize how metazoan retromer components assemble to enable its engagement with endosomal membranes, where it sorts cargo receptors from endosomes to the trans-Golgi network or plasma membrane through recognition of sorting motifs in their cytoplasmic tails. In this review, we examine retromer regulation by exploring its assembled structure with an emphasis on how a range of adaptor proteins shape the process of receptor trafficking. Specifically, we focus on how retromer is recruited to endosomes, selects cargoes, and generates tubulovesicular carriers that deliver cargoes to target membranes. We also examine how cells adapt to distinct metabolic states by coordinating retromer expression and function. We contrast similarities and differences between retromer and its related complexes: retriever and commander/CCC, as well as their interplay in receptor trafficking. We elucidate how loss of retromer regulation is central to the pathology of various neurogenerative and metabolic diseases, as well as microbial infections, and highlight both opportunities and cautions for therapeutics that target retromer. Finally, with a focus on understanding the mechanisms that govern retromer regulation, we outline new directions for the field moving forward.
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Affiliation(s)
- Julian M. Carosi
- Lysosomal Health in Ageing, Lifelong Health, South Australian Health and Medical Research Institute (SAHMRI), Adelaide, South Australia, Australia
- Centre for Cancer Biology, University of South Australia (UniSA), Adelaide, South Australia, Australia
- School of Biological Sciences, Faculty of Sciences, Engineering and Technology, The University of Adelaide, Adelaide, South Australia, Australia
| | - Donna Denton
- Centre for Cancer Biology, University of South Australia (UniSA), Adelaide, South Australia, Australia
| | - Sharad Kumar
- Centre for Cancer Biology, University of South Australia (UniSA), Adelaide, South Australia, Australia
- Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, South Australia, Australia
| | - Timothy J. Sargeant
- Lysosomal Health in Ageing, Lifelong Health, South Australian Health and Medical Research Institute (SAHMRI), Adelaide, South Australia, Australia
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Jha SG, Larson ER. Diversity of retromer-mediated vesicular trafficking pathways in plants. FRONTIERS IN PLANT SCIENCE 2023; 14:1184047. [PMID: 37409293 PMCID: PMC10319002 DOI: 10.3389/fpls.2023.1184047] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 05/31/2023] [Indexed: 07/07/2023]
Abstract
The plant endomembrane system is organized and regulated by large gene families that encode proteins responsible for the spatiotemporal delivery and retrieval of cargo throughout the cell and to and from the plasma membrane. Many of these regulatory molecules form functional complexes like the SNAREs, exocyst, and retromer, which are required for the delivery, recycling, and degradation pathways of cellular components. The functions of these complexes are well conserved in eukaryotes, but the extreme expansion of the protein subunit families in plants suggests that plant cells require more regulatory specialization when compared with other eukaryotes. The retromer is associated with retrograde sorting and trafficking of protein cargo back towards the TGN and vacuole in plants, while in animals, there is new evidence that the VPS26C ortholog is associated with recycling or 'retrieving' proteins back to the PM from the endosomes. The human VPS26C was shown to rescue vps26c mutant phenotypes in Arabidopsis thaliana, suggesting that the retriever function could be conserved in plants. This switch from retromer to retriever function may be associated with core complexes that include the VPS26C subunit in plants, similar to what has been suggested in other eukaryotic systems. We review what is known about retromer function in light of recent findings on functional diversity and specialization of the retromer complex in plants.
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Affiliation(s)
- Suryatapa Ghosh Jha
- William Myron Keck Science Department - Biology, Claremont McKenna, Pitzer, and Scripps Colleges, Claremont, CA, United States
| | - Emily R. Larson
- School of Biological Sciences, University of Bristol, Bristol, United Kingdom
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7
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Simonetti B, Daly JL, Cullen PJ. Out of the ESCPE room: Emerging roles of endosomal SNX-BARs in receptor transport and host-pathogen interaction. Traffic 2023; 24:234-250. [PMID: 37089068 PMCID: PMC10768393 DOI: 10.1111/tra.12885] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 02/22/2023] [Accepted: 03/28/2023] [Indexed: 04/25/2023]
Abstract
Several functions of the human cell, such as sensing nutrients, cell movement and interaction with the surrounding environment, depend on a myriad of transmembrane proteins and their associated proteins and lipids (collectively termed "cargoes"). To successfully perform their tasks, cargo must be sorted and delivered to the right place, at the right time, and in the right amount. To achieve this, eukaryotic cells have evolved a highly organized sorting platform, the endosomal network. Here, a variety of specialized multiprotein complexes sort cargo into itineraries leading to either their degradation or their recycling to various organelles for further rounds of reuse. A key sorting complex is the Endosomal SNX-BAR Sorting Complex for Promoting Exit (ESCPE-1) that promotes the recycling of an array of cargos to the plasma membrane and/or the trans-Golgi network. ESCPE-1 recognizes a hydrophobic-based sorting motif in numerous cargoes and orchestrates their packaging into tubular carriers that pinch off from the endosome and travel to the target organelle. A wide range of pathogens mimic this sorting motif to hijack ESCPE-1 transport to promote their invasion and survival within infected cells. In other instances, ESCPE-1 exerts restrictive functions against pathogens by limiting their replication and infection. In this review, we discuss ESCPE-1 assembly and functions, with a particular focus on recent advances in the understanding of its role in membrane trafficking, cellular homeostasis and host-pathogen interaction.
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Affiliation(s)
- Boris Simonetti
- Charles River Laboratories, Discovery House, Quays Office ParkConference Avenue, PortisheadBristolUK
| | - James L. Daly
- Department of Infectious DiseasesSchool of Immunology and Microbial Sciences, Guy's Hospital, King's College LondonLondonUK
| | - Peter J. Cullen
- School of Biochemistry, Faculty of Life Sciences, Biomedical Sciences BuildingUniversity of BristolBristolUK
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8
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Da Graça J, Morel E. Canonical and Non-Canonical Roles of SNX1 and SNX2 in Endosomal Membrane Dynamics. CONTACT (THOUSAND OAKS (VENTURA COUNTY, CALIF.)) 2023; 6:25152564231217867. [PMID: 38033809 PMCID: PMC10683387 DOI: 10.1177/25152564231217867] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 11/07/2023] [Accepted: 11/15/2023] [Indexed: 12/02/2023]
Abstract
Sorting nexins (SNXs) are a family of membrane-binding proteins known to play a critical role in regulating endocytic pathway sorting and endosomal membrane trafficking. Among them, SNX1 and SNX2 are members of the SNX-BAR subfamily and possess a membrane-curvature domain and a phosphoinositide-binding domain, which enables their stabilization at the phosphatidylinositol-3-phosphate (PI3P)-positive surface of endosomes. While their binding to PI3P-positive platforms facilitates interaction with endosomal partners and stabilization at the endosomal membrane, their SNX-BAR region is pivotal for generating membrane tubulation from endosomal compartments. In this context, their primary identified biological roles-and their partnership-are tightly associated with the retromer and endosomal SNX-BAR sorting complex for promoting exit 1 complex trafficking, facilitating the transport of cargoes from early endosomes to the secretory pathway. However, recent literature indicates that these proteins also possess biological functions in other aspects of endosomal features and sorting processes. Notably, SNX2 has been found to regulate endosome-endoplasmic reticulum (ER) contact sites through its interaction with VAP proteins at the ER membrane. Furthermore, data from our laboratory show that SNX1 and SNX2 are involved in the tubulation of early endosomes toward ER sites associated with autophagy initiation during starvation. These findings shed light on a novel role of SNXs in inter-organelle tethering and communication. In this concise review, we will explore the non-retromer functions of SNX1 and SNX2, specifically focusing on their involvement in endosomal membrane dynamics during stress sensing and autophagy-associated processes.
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Affiliation(s)
- Juliane Da Graça
- Université Paris Cité, INSERM UMR-S1151, CNRS UMR-S8253, Institut Necker Enfants Malades, Paris, France
| | - Etienne Morel
- Université Paris Cité, INSERM UMR-S1151, CNRS UMR-S8253, Institut Necker Enfants Malades, Paris, France
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9
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Liu N, Liu K, Yang C. WDR91 specifies the endosomal retrieval subdomain for retromer-dependent recycling. J Cell Biol 2022; 221:213515. [PMID: 36190447 PMCID: PMC9531996 DOI: 10.1083/jcb.202203013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 08/04/2022] [Accepted: 09/19/2022] [Indexed: 12/13/2022] Open
Abstract
Retromer-dependent endosomal recycling of membrane receptors requires Rab7, sorting nexin (SNX)-retromer, and factors that regulate endosomal actin organization. It is not fully understood how these factors cooperate to form endosomal subdomains for cargo retrieval and recycling. Here, we report that WDR91, a Rab7 effector, is the key factor that specifies the endosomal retrieval subdomain. Loss of WDR91 causes defective recycling of both intracellular and cell surface receptors. WDR91 interacts with SNXs through their PX domain, and with VPS35, thus promoting their interaction with Rab7. WDR91 also interacts with the WASH subunit FAM21. In WDR91-deficient cells, Rab7, SNX-retromer, and FAM21 fail to localize to endosomal subdomains, and endosomal actin organization is impaired. Re-expression of WDR91 enables Rab7, SNX-retromer, and FAM21 to concentrate at WDR91-specific endosomal subdomains, where retromer-mediated membrane tubulation and release occur. Thus, WDR91 coordinates Rab7 with SNX-retromer and WASH to establish the endosomal retrieval subdomains required for retromer-mediated endosomal recycling.
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Affiliation(s)
- Nan Liu
- State Key Laboratory of Conservation and Utilization of Bio-resources in Yunnan, Center for Life Sciences, School of Life Sciences, Yunnan University, Kunming, China
| | - Kai Liu
- State Key Laboratory of Conservation and Utilization of Bio-resources in Yunnan, Center for Life Sciences, School of Life Sciences, Yunnan University, Kunming, China
| | - Chonglin Yang
- State Key Laboratory of Conservation and Utilization of Bio-resources in Yunnan, Center for Life Sciences, School of Life Sciences, Yunnan University, Kunming, China,Correspondence to Chonglin Yang:
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10
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Rodgers SJ, Jones EI, Arumugam S, Hamila SA, Danne J, Gurung R, Eramo MJ, Nanayakkara R, Ramm G, McGrath MJ, Mitchell CA. Endosome maturation links PI3Kα signaling to lysosome repopulation during basal autophagy. EMBO J 2022; 41:e110398. [PMID: 35968799 PMCID: PMC9531306 DOI: 10.15252/embj.2021110398] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 07/19/2022] [Accepted: 07/21/2022] [Indexed: 12/24/2022] Open
Abstract
Autophagy depends on the repopulation of lysosomes to degrade intracellular components and recycle nutrients. How cells co‐ordinate lysosome repopulation during basal autophagy, which occurs constitutively under nutrient‐rich conditions, is unknown. Here, we identify an endosome‐dependent phosphoinositide pathway that links PI3Kα signaling to lysosome repopulation during basal autophagy. We show that PI3Kα‐derived PI(3)P generated by INPP4B on late endosomes was required for basal but not starvation‐induced autophagic degradation. PI(3)P signals were maintained as late endosomes matured into endolysosomes, and served as the substrate for the 5‐kinase, PIKfyve, to generate PI(3,5)P2. The SNX‐BAR protein, SNX2, was recruited to endolysosomes by PI(3,5)P2 and promoted lysosome reformation. Inhibition of INPP4B/PIKfyve‐dependent lysosome reformation reduced autophagic clearance of protein aggregates during proteotoxic stress leading to increased cytotoxicity. Therefore under nutrient‐rich conditions, PI3Kα, INPP4B, and PIKfyve sequentially contribute to basal autophagic degradation and protection from proteotoxic stress via PI(3,5)P2‐dependent lysosome reformation from endolysosomes. These findings reveal that endosome maturation couples PI3Kα signaling to lysosome reformation during basal autophagy.
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Affiliation(s)
- Samuel J Rodgers
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Emily I Jones
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Senthil Arumugam
- Department of Anatomy and Developmental Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia.,European Molecular Biological Laboratory Australia, Monash University, Clayton, VIC, Australia
| | - Sabryn A Hamila
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Jill Danne
- Monash Ramaciotti Centre for Cryo Electron Microscopy, A Node of Microscopy Australia, Monash University, Clayton, VIC, Australia
| | - Rajendra Gurung
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Matthew J Eramo
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Randini Nanayakkara
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia.,Monash Ramaciotti Centre for Cryo Electron Microscopy, A Node of Microscopy Australia, Monash University, Clayton, VIC, Australia
| | - Georg Ramm
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia.,Monash Ramaciotti Centre for Cryo Electron Microscopy, A Node of Microscopy Australia, Monash University, Clayton, VIC, Australia
| | - Meagan J McGrath
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Christina A Mitchell
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
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11
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Yoshida S, Hasegawa T. Beware of Misdelivery: Multifaceted Role of Retromer Transport in Neurodegenerative Diseases. Front Aging Neurosci 2022; 14:897688. [PMID: 35601613 PMCID: PMC9120357 DOI: 10.3389/fnagi.2022.897688] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 04/19/2022] [Indexed: 11/13/2022] Open
Abstract
Retromer is a highly integrated multimeric protein complex that mediates retrograde cargo sorting from endosomal compartments. In concert with its accessory proteins, the retromer drives packaged cargoes to tubular and vesicular structures, thereby transferring them to the trans-Golgi network or to the plasma membrane. In addition to the endosomal trafficking, the retromer machinery participates in mitochondrial dynamics and autophagic processes and thus contributes to cellular homeostasis. The retromer components and their associated molecules are expressed in different types of cells including neurons and glial cells, and accumulating evidence from genetic and biochemical studies suggests that retromer dysfunction is profoundly involved in the pathogenesis of neurodegenerative diseases including Alzheimer’s Disease and Parkinson’s disease. Moreover, targeting retromer components could alleviate the neurodegenerative process, suggesting that the retromer complex may serve as a promising therapeutic target. In this review, we will provide the latest insight into the regulatory mechanisms of retromer and discuss how its dysfunction influences the pathological process leading to neurodegeneration.
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Affiliation(s)
- Shun Yoshida
- Division of Neurology, Department of Neuroscience and Sensory Organs, Tohoku University Graduate School of Medicine, Sendai, Japan
- Department of Neurology, National Hospital Organization Yonezawa Hospital, Yonezawa, Japan
| | - Takafumi Hasegawa
- Division of Neurology, Department of Neuroscience and Sensory Organs, Tohoku University Graduate School of Medicine, Sendai, Japan
- *Correspondence: Takafumi Hasegawa,
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12
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Ciesielska A, Krawczy M, Sas-Nowosielska H, Hromada-Judycka A, Kwiatkowska K. CD14 recycling modulates LPS-induced inflammatory responses of murine macrophages. Traffic 2022; 23:310-330. [PMID: 35411668 DOI: 10.1111/tra.12842] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Revised: 03/07/2022] [Accepted: 04/01/2022] [Indexed: 11/28/2022]
Abstract
TLR4 is activated by the bacterial endotoxin lipopolysaccharide (LPS) and triggers two pro-inflammatory signaling cascades: a MyD88-dependent one in the plasma membrane, and the following TRIF-dependent one in endosomes. An inadequate inflammatory reaction can be detrimental for the organism by leading to sepsis. Therefore, novel approaches to therapeutic modulation of TLR4 signaling are being sought after. The TLR4 activity is tightly connected with the presence of CD14, a GPI-anchored protein that transfers LPS monomers to the receptor and controls its endocytosis. In this study we focused on CD14 trafficking as a still poorly understood factor affecting TLR4 activity. Two independent assays were used to show that after endocytosis CD14 can recycle back to the plasma membrane in both unstimulated and stimulated cells. This route of CD14 trafficking can be controlled by sorting nexins (SNX) 1, 2, and 6, and is important for maintaining the surface level and the total level of CD14, but can also affect the amount of TLR4. Silencing of these SNXs attenuated especially the CD14-dependent endosomal signaling of TLR4, making them a new target for therapeutic regulation of the inflammatory response of macrophages to LPS.
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Affiliation(s)
- Anna Ciesielska
- Laboratory of Molecular Membrane Biology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw, Poland
| | - Marta Krawczy
- Laboratory of Molecular Membrane Biology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw, Poland
| | - Hanna Sas-Nowosielska
- Laboratory of Molecular Basis of Cell Motility, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur St., 02-093 Warsaw, Poland
| | - Aneta Hromada-Judycka
- Laboratory of Molecular Membrane Biology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw, Poland
| | - Katarzyna Kwiatkowska
- Laboratory of Molecular Membrane Biology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw, Poland
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13
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Buser DP, Bader G, Spiess M. Retrograde transport of CDMPR depends on several machineries as analyzed by sulfatable nanobodies. Life Sci Alliance 2022; 5:5/7/e202101269. [PMID: 35314489 PMCID: PMC8961009 DOI: 10.26508/lsa.202101269] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 03/08/2022] [Accepted: 03/09/2022] [Indexed: 11/24/2022] Open
Abstract
Nanobody toolkit enables the quantitative analysis of endosome-to-TGN transport of the mannose-6-phosphate receptor in cells depleted of retrograde transport machineries Retrograde protein transport from the cell surface and endosomes to the TGN is essential for membrane homeostasis in general and for the recycling of mannose-6-phosphate receptors (MPRs) for sorting of lysosomal hydrolases in particular. We used a nanobody-based sulfation tool to more directly determine transport kinetics from the plasma membrane to the TGN for the cation-dependent MPR (CDMPR) with and without rapid or gradual inactivation of candidate machinery proteins. Although knockdown of retromer (Vps26), epsinR, or Rab9a reduced CDMPR arrival to the TGN, no effect was observed upon silencing of TIP47. Strikingly, when retrograde transport was analyzed by rapamycin-induced rapid depletion (knocksideways) or long-term depletion by knockdown of the clathrin adaptor AP-1 or of the GGA machinery, distinct phenotypes in sulfation kinetics were observed, suggesting a potential role of GGA adaptors in retrograde and anterograde transport. Our study illustrates the usefulness of derivatized, sulfation-competent nanobodies, reveals novel insights into CDMPR trafficking biology, and further outlines that the selection of machinery inactivation is critical for phenotype analysis.
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Affiliation(s)
| | - Gaétan Bader
- Biozentrum, University of Basel, Basel, Switzerland
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14
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Class III PI3K Biology. Curr Top Microbiol Immunol 2022; 436:69-93. [DOI: 10.1007/978-3-031-06566-8_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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15
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Koçmar T, Çağlayan E, Rayaman E, Nagata K, Turan K. Human sorting nexin 2 protein interacts with Influenza A virus PA protein and has a negative regulatory effect on the virus replication. Mol Biol Rep 2021; 49:497-510. [PMID: 34817777 PMCID: PMC8611637 DOI: 10.1007/s11033-021-06906-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 10/29/2021] [Indexed: 11/03/2022]
Abstract
Background Replication of the influenza A viruses occurs in the cells through the viral RdRP consisting of PB1, PB2, and PA. Several cellular proteins are involved in these processes. This study aims to reveal the interaction between human SNX2 protein and the PA protein and the effects of the SNX2 on the virus replication. Results To identify potential host interacting proteins to the PA, yeast two-hybrid assay was carried out with HEK293 cell cDNA library and the PA as a bait. We focused on SNX2 protein, which interacts with the PA in the yeast cells. By using the co-immunoprecipitation assays, it has been demonstrated that the amino-terminal part of the PA was important for binding to the SNX2. Immunolocalization of the proteins in HeLa cells supported this interaction. Knockdown of the SNX2 with siRNA in the cells resulted in a significant increase in both viral transcripts and virus growth. However, the increase of SNX2 in transfected cells didn’t cause a significant change in the viral RdRP activity in minireplicon assay. This may suggest that the negative effect of SNX2 on the virus replication could be saturated with its authentic intra-cellular amount. Conclusions This study revealed that the SNX2 and PA protein interact with each other in both yeast and HEK293 cells, and the SNX2 has a negative regulatory function on the virus replication. However, more knowledge is required to elucidate the action mechanism of the SNX2 on the influenza A virus replication at the molecular level. Supplementary Information The online version contains supplementary material available at 10.1007/s11033-021-06906-9.
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Affiliation(s)
- Tuğba Koçmar
- Institute of Health Sciences, Marmara University, Istanbul, Turkey
| | - Elif Çağlayan
- University of Health Sciences Kartal Koşuyolu High Speciality Educational and Research Hospital, Istanbul, Turkey
| | - Erkan Rayaman
- Department of Pharmaceutical Microbiology, Faculty of Pharmacy, Marmara University, Istanbul, Turkey
| | - Kyosuke Nagata
- Department of Infection Biology, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Japan
| | - Kadir Turan
- Department of Basic Pharmaceutical Sciences, Faculty of Pharmacy, Marmara University, Istanbul, Turkey.
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16
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Unveiling the cryo-EM structure of retromer. Biochem Soc Trans 2021; 48:2261-2272. [PMID: 33125482 DOI: 10.1042/bst20200552] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Revised: 09/10/2020] [Accepted: 09/14/2020] [Indexed: 12/29/2022]
Abstract
Retromer (VPS26/VPS35/VPS29) is a highly conserved eukaryotic protein complex that localizes to endosomes to sort transmembrane protein cargoes into vesicles and elongated tubules. Retromer mediates retrieval pathways from endosomes to the trans-Golgi network in all eukaryotes and further facilitates recycling pathways to the plasma membrane in metazoans. In cells, retromer engages multiple partners to orchestrate the formation of tubulovesicular structures, including sorting nexin (SNX) proteins, cargo adaptors, GTPases, regulators, and actin remodeling proteins. Retromer-mediated pathways are especially important for sorting cargoes required for neuronal maintenance, which links retromer loss or mutations to multiple human brain diseases and disorders. Structural and biochemical studies have long contributed to the understanding of retromer biology, but recent advances in cryo-electron microscopy and cryo-electron tomography have further uncovered exciting new snapshots of reconstituted retromer structures. These new structures reveal retromer assembles into an arch-shaped scaffold and suggest the scaffold may be flexible and adaptable in cells. Interactions with cargo adaptors, particularly SNXs, likely orient the scaffold with respect to phosphatidylinositol-3-phosphate (PtdIns3P)-enriched membranes. Pharmacological small molecule chaperones have further been shown to stabilize retromer in cultured cell and mouse models, but mechanisms by which these molecules bind remain unknown. This review will emphasize recent structural and biophysical advances in understanding retromer structure as the field moves towards a molecular view of retromer assembly and regulation on membranes.
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17
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Kervin TA, Wiseman BC, Overduin M. Phosphoinositide Recognition Sites Are Blocked by Metabolite Attachment. Front Cell Dev Biol 2021; 9:690461. [PMID: 34368138 PMCID: PMC8340361 DOI: 10.3389/fcell.2021.690461] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Accepted: 06/18/2021] [Indexed: 12/16/2022] Open
Abstract
Membrane readers take part in trafficking and signaling processes by localizing proteins to organelle surfaces and transducing molecular information. They accomplish this by engaging phosphoinositides (PIs), a class of lipid molecules which are found in different proportions in various cellular membranes. The prototypes are the PX domains, which exhibit a range of specificities for PIs. Our meta-analysis indicates that recognition of membranes by PX domains is specifically controlled by modification of lysine and arginine residues including acetylation, hydroxyisobutyrylation, glycation, malonylation, methylation and succinylation of sidechains that normally bind headgroups of phospholipids including organelle-specific PI signals. Such metabolite-modulated residues in lipid binding elements are named MET-stops here to highlight their roles as erasers of membrane reader functions. These modifications are concentrated in the membrane binding sites of half of all 49 PX domains in the human proteome and correlate with phosphoregulatory sites, as mapped using the Membrane Optimal Docking Area (MODA) algorithm. As these motifs are mutated and modified in various cancers and the responsible enzymes serve as potential drug targets, the discovery of MET-stops as a widespread inhibitory mechanism may aid in the development of diagnostics and therapeutics aimed at the readers, writers and erasers of the PI code.
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Affiliation(s)
- Troy A Kervin
- Department of Biochemistry, University of Alberta, Edmonton, AB, Canada
| | - Brittany C Wiseman
- Department of Biochemistry, University of Alberta, Edmonton, AB, Canada.,Molecular and Cellular Biology, MacEwan University, Edmonton, AB, Canada.,SMALP Network, Edmonton, AB, Canada
| | - Michael Overduin
- Department of Biochemistry, University of Alberta, Edmonton, AB, Canada.,SMALP Network, Edmonton, AB, Canada
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18
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Kervin TA, Overduin M. Regulation of the Phosphoinositide Code by Phosphorylation of Membrane Readers. Cells 2021; 10:cells10051205. [PMID: 34069055 PMCID: PMC8156045 DOI: 10.3390/cells10051205] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 05/07/2021] [Accepted: 05/09/2021] [Indexed: 02/07/2023] Open
Abstract
The genetic code that dictates how nucleic acids are translated into proteins is well known, however, the code through which proteins recognize membranes remains mysterious. In eukaryotes, this code is mediated by hundreds of membrane readers that recognize unique phosphatidylinositol phosphates (PIPs), which demark organelles to initiate localized trafficking and signaling events. The only superfamily which specifically detects all seven PIPs are the Phox homology (PX) domains. Here, we reveal that throughout evolution, these readers are universally regulated by the phosphorylation of their PIP binding surfaces based on our analysis of existing and modelled protein structures and phosphoproteomic databases. These PIP-stops control the selective targeting of proteins to organelles and are shown to be key determinants of high-fidelity PIP recognition. The protein kinases responsible include prominent cancer targets, underscoring the critical role of regulated membrane readership.
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19
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Seaman MNJ. The Retromer Complex: From Genesis to Revelations. Trends Biochem Sci 2021; 46:608-620. [PMID: 33526371 DOI: 10.1016/j.tibs.2020.12.009] [Citation(s) in RCA: 65] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 12/15/2020] [Accepted: 12/17/2020] [Indexed: 12/13/2022]
Abstract
The retromer complex has a well-established role in endosomal protein sorting, being necessary for maintaining the dynamic localisation of hundreds of membrane proteins that traverse the endocytic system. Retromer function and dysfunction is linked with neurodegenerative diseases, including Alzheimer's and Parkinson's disease, and many pathogens, both viral and bacterial, exploit or interfere in retromer function for their own ends. In this review, the history of retromer is distilled into a concentrated form that spans the identification of retromer to recent discoveries that have shed new light on how retromer functions in endosomal protein sorting and why retromer is increasingly being viewed as a potential therapeutic target in neurodegenerative disease.
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Affiliation(s)
- Matthew N J Seaman
- University of Cambridge, Cambridge Institute for Medical Research, The Keith Peters Building, Cambridge Biomedical Campus, Cambridge, CB2 0XY, UK.
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20
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Antón Z, Betin VMS, Simonetti B, Traer CJ, Attar N, Cullen PJ, Lane JD. A heterodimeric SNX4--SNX7 SNX-BAR autophagy complex coordinates ATG9A trafficking for efficient autophagosome assembly. J Cell Sci 2020; 133:jcs246306. [PMID: 32513819 PMCID: PMC7375690 DOI: 10.1242/jcs.246306] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Accepted: 06/02/2020] [Indexed: 11/24/2022] Open
Abstract
The sorting nexins (SNXs) are a family of peripheral membrane proteins that direct protein trafficking decisions within the endocytic network. Emerging evidence in yeast and mammalian cells implicates a subgroup of SNXs in selective and non-selective forms of autophagy. Using siRNA and CRISPR-Cas9, we demonstrate that the SNX-BAR protein SNX4 is needed for efficient LC3 (also known as MAP1LC3) lipidation and autophagosome assembly in mammalian cells. SNX-BARs exist as homo- and hetero-dimers, and we show that SNX4 forms functional heterodimers with either SNX7 or SNX30 that associate with tubulovesicular endocytic membranes. Detailed image-based analysis during the early stages of autophagosome assembly reveals that SNX4-SNX7 is an autophagy-specific SNX-BAR heterodimer, required for efficient recruitment and/or retention of core autophagy regulators at the nascent isolation membrane. SNX4 partially colocalises with juxtanuclear ATG9A-positive membranes, with our data linking the autophagy defect upon SNX4 disruption to the mis-trafficking and/or retention of ATG9A in the Golgi region. Taken together, our findings show that the SNX4-SNX7 heterodimer coordinates ATG9A trafficking within the endocytic network to establish productive autophagosome assembly sites, thus extending knowledge of SNXs as positive regulators of autophagy.
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Affiliation(s)
- Zuriñe Antón
- Cell Biology Laboratories, School of Biochemistry, Medical Sciences Building, University of Bristol, Bristol BS8 1TD, UK
| | - Virginie M S Betin
- Cell Biology Laboratories, School of Biochemistry, Medical Sciences Building, University of Bristol, Bristol BS8 1TD, UK
| | - Boris Simonetti
- Henry Wellcome Integrated Signalling Laboratories, School of Biochemistry, Medical Sciences Building, University of Bristol, Bristol BS8 1TD, UK
| | - Colin J Traer
- Henry Wellcome Integrated Signalling Laboratories, School of Biochemistry, Medical Sciences Building, University of Bristol, Bristol BS8 1TD, UK
| | - Naomi Attar
- Henry Wellcome Integrated Signalling Laboratories, School of Biochemistry, Medical Sciences Building, University of Bristol, Bristol BS8 1TD, UK
| | - Peter J Cullen
- Henry Wellcome Integrated Signalling Laboratories, School of Biochemistry, Medical Sciences Building, University of Bristol, Bristol BS8 1TD, UK
| | - Jon D Lane
- Cell Biology Laboratories, School of Biochemistry, Medical Sciences Building, University of Bristol, Bristol BS8 1TD, UK
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21
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de Araujo MEG, Liebscher G, Hess MW, Huber LA. Lysosomal size matters. Traffic 2019; 21:60-75. [PMID: 31808235 PMCID: PMC6972631 DOI: 10.1111/tra.12714] [Citation(s) in RCA: 124] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 10/30/2019] [Accepted: 10/31/2019] [Indexed: 12/25/2022]
Abstract
Lysosomes are key cellular catabolic centers that also perform fundamental metabolic, signaling and quality control functions. Lysosomes are not static and they respond dynamically to intra‐ and extracellular stimuli triggering changes in organelle numbers, size and position. Such physical changes have a strong impact on lysosomal activity ultimately influencing cellular homeostasis. In this review, we summarize the current knowledge on lysosomal size regulation, on its physiological role(s) and association to several disease conditions.
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Affiliation(s)
- Mariana E G de Araujo
- Institute of Cell Biology, Biocenter, Medical University of Innsbruck, Innsbruck, Austria
| | - Gudrun Liebscher
- Institute of Cell Biology, Biocenter, Medical University of Innsbruck, Innsbruck, Austria
| | - Michael W Hess
- Institute of Histology and Embryology, Medical University of Innsbruck, Innsbruck, Austria
| | - Lukas A Huber
- Institute of Cell Biology, Biocenter, Medical University of Innsbruck, Innsbruck, Austria.,Austrian Drug Screening Institute, ADSI, Innsbruck, Austria
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22
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Freeman SA, Uderhardt S, Saric A, Collins RF, Buckley CM, Mylvaganam S, Boroumand P, Plumb J, Germain RN, Ren D, Grinstein S. Lipid-gated monovalent ion fluxes regulate endocytic traffic and support immune surveillance. Science 2019; 367:301-305. [PMID: 31806695 DOI: 10.1126/science.aaw9544] [Citation(s) in RCA: 104] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 10/08/2019] [Accepted: 11/25/2019] [Indexed: 12/21/2022]
Abstract
Despite ongoing (macro)pinocytosis of extracellular fluid, the volume of the endocytic pathway remains unchanged. To investigate the underlying mechanism, we used high-resolution video imaging to analyze the fate of macropinosomes formed by macrophages in vitro and in situ. Na+, the primary cationic osmolyte internalized, exited endocytic vacuoles via two-pore channels, accompanied by parallel efflux of Cl- and osmotically coupled water. The resulting shrinkage caused crenation of the membrane, which fostered recruitment of curvature-sensing proteins. These proteins stabilized tubules and promoted their elongation, driving vacuolar remodeling, receptor recycling, and resolution of the organelles. Failure to resolve internalized fluid impairs the tissue surveillance activity of resident macrophages. Thus, osmotically driven increases in the surface-to-volume ratio of endomembranes promote traffic between compartments and help to ensure tissue homeostasis.
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Affiliation(s)
- Spencer A Freeman
- Program in Cell Biology, Peter Gilgan Centre for Research and Learning, Hospital for Sick Children, Toronto, ON, Canada.
| | - Stefan Uderhardt
- Lymphocyte Biology Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA.,Department of Internal Medicine 3 - Rheumatology and Immunology, Universitätsklinikum Erlangen and Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Amra Saric
- Neurosciences and Cellular and Structural Biology Division, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Richard F Collins
- Program in Cell Biology, Peter Gilgan Centre for Research and Learning, Hospital for Sick Children, Toronto, ON, Canada
| | - Catherine M Buckley
- Program in Cell Biology, Peter Gilgan Centre for Research and Learning, Hospital for Sick Children, Toronto, ON, Canada.,Institute of Microbiology and Infection and School of Biosciences, University of Birmingham, Edgbaston, Birmingham, UK
| | - Sivakami Mylvaganam
- Program in Cell Biology, Peter Gilgan Centre for Research and Learning, Hospital for Sick Children, Toronto, ON, Canada
| | - Parastoo Boroumand
- Program in Cell Biology, Peter Gilgan Centre for Research and Learning, Hospital for Sick Children, Toronto, ON, Canada
| | - Jonathan Plumb
- Program in Cell Biology, Peter Gilgan Centre for Research and Learning, Hospital for Sick Children, Toronto, ON, Canada
| | - Ronald N Germain
- Lymphocyte Biology Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Dejian Ren
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Sergio Grinstein
- Program in Cell Biology, Peter Gilgan Centre for Research and Learning, Hospital for Sick Children, Toronto, ON, Canada. .,Keenan Research Centre of the Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, ON, Canada
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23
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Chen K, Healy MD, Collins BM. Towards a molecular understanding of endosomal trafficking by Retromer and Retriever. Traffic 2019; 20:465-478. [DOI: 10.1111/tra.12649] [Citation(s) in RCA: 92] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 04/15/2019] [Accepted: 04/15/2019] [Indexed: 12/16/2022]
Affiliation(s)
- Kai‐En Chen
- Institute for Molecular Bioscience University of Queensland St. Lucia Queensland Australia
| | - Michael D. Healy
- Institute for Molecular Bioscience University of Queensland St. Lucia Queensland Australia
| | - Brett M. Collins
- Institute for Molecular Bioscience University of Queensland St. Lucia Queensland Australia
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24
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Koskimäki J, Girard R, Li Y, Saadat L, Zeineddine HA, Lightle R, Moore T, Lyne S, Avner K, Shenkar R, Cao Y, Shi C, Polster SP, Zhang D, Carrión-Penagos J, Romanos S, Fonseca G, Lopez-Ramirez MA, Chapman EM, Popiel E, Tang AT, Akers A, Faber P, Andrade J, Ginsberg M, Derry WB, Kahn ML, Marchuk DA, Awad IA. Comprehensive transcriptome analysis of cerebral cavernous malformation across multiple species and genotypes. JCI Insight 2019; 4:126167. [PMID: 30728328 DOI: 10.1172/jci.insight.126167] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 01/03/2019] [Indexed: 12/18/2022] Open
Abstract
The purpose of this study was to determine important genes, functions, and networks contributing to the pathobiology of cerebral cavernous malformation (CCM) from transcriptomic analyses across 3 species and 2 disease genotypes. Sequencing of RNA from laser microdissected neurovascular units of 5 human surgically resected CCM lesions, mouse brain microvascular endothelial cells, Caenorhabditis elegans with induced Ccm gene loss, and their respective controls provided differentially expressed genes (DEGs). DEGs from mouse and C. elegans were annotated into human homologous genes. Cross-comparisons of DEGs between species and genotypes, as well as network and gene ontology (GO) enrichment analyses, were performed. Among hundreds of DEGs identified in each model, common genes and 1 GO term (GO:0051656, establishment of organelle localization) were commonly identified across the different species and genotypes. In addition, 24 GO functions were present in 4 of 5 models and were related to cell-to-cell adhesion, neutrophil-mediated immunity, ion transmembrane transporter activity, and responses to oxidative stress. We have provided a comprehensive transcriptome library of CCM disease across species and for the first time to our knowledge in Ccm1/Krit1 versus Ccm3/Pdcd10 genotypes. We have provided examples of how results can be used in hypothesis generation or mechanistic confirmatory studies.
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Affiliation(s)
- Janne Koskimäki
- Neurovascular Surgery Program, Section of Neurosurgery, The University of Chicago Medicine and Biological Sciences, Chicago, Illinois, USA
| | - Romuald Girard
- Neurovascular Surgery Program, Section of Neurosurgery, The University of Chicago Medicine and Biological Sciences, Chicago, Illinois, USA
| | - Yan Li
- Center for Research Informatics, The University of Chicago, Chicago, Illinois, USA
| | - Laleh Saadat
- Neurovascular Surgery Program, Section of Neurosurgery, The University of Chicago Medicine and Biological Sciences, Chicago, Illinois, USA
| | - Hussein A Zeineddine
- Neurovascular Surgery Program, Section of Neurosurgery, The University of Chicago Medicine and Biological Sciences, Chicago, Illinois, USA
| | - Rhonda Lightle
- Neurovascular Surgery Program, Section of Neurosurgery, The University of Chicago Medicine and Biological Sciences, Chicago, Illinois, USA
| | - Thomas Moore
- Neurovascular Surgery Program, Section of Neurosurgery, The University of Chicago Medicine and Biological Sciences, Chicago, Illinois, USA
| | - Seán Lyne
- Neurovascular Surgery Program, Section of Neurosurgery, The University of Chicago Medicine and Biological Sciences, Chicago, Illinois, USA
| | - Kenneth Avner
- Neurovascular Surgery Program, Section of Neurosurgery, The University of Chicago Medicine and Biological Sciences, Chicago, Illinois, USA
| | - Robert Shenkar
- Neurovascular Surgery Program, Section of Neurosurgery, The University of Chicago Medicine and Biological Sciences, Chicago, Illinois, USA
| | - Ying Cao
- Neurovascular Surgery Program, Section of Neurosurgery, The University of Chicago Medicine and Biological Sciences, Chicago, Illinois, USA
| | - Changbin Shi
- Neurovascular Surgery Program, Section of Neurosurgery, The University of Chicago Medicine and Biological Sciences, Chicago, Illinois, USA
| | - Sean P Polster
- Neurovascular Surgery Program, Section of Neurosurgery, The University of Chicago Medicine and Biological Sciences, Chicago, Illinois, USA
| | - Dongdong Zhang
- Neurovascular Surgery Program, Section of Neurosurgery, The University of Chicago Medicine and Biological Sciences, Chicago, Illinois, USA
| | - Julián Carrión-Penagos
- Neurovascular Surgery Program, Section of Neurosurgery, The University of Chicago Medicine and Biological Sciences, Chicago, Illinois, USA
| | - Sharbel Romanos
- Neurovascular Surgery Program, Section of Neurosurgery, The University of Chicago Medicine and Biological Sciences, Chicago, Illinois, USA
| | | | | | - Eric M Chapman
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Evelyn Popiel
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Alan T Tang
- Department of Medicine and Cardiovascular Institute, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Amy Akers
- Angioma Alliance, Norfolk, Virginia, USA
| | - Pieter Faber
- University of Chicago Genomics Facility, The University of Chicago, Chicago, Illinois, USA
| | - Jorge Andrade
- Center for Research Informatics, The University of Chicago, Chicago, Illinois, USA
| | - Mark Ginsberg
- Department of Medicine, UCSD, La Jolla, California, USA
| | - W Brent Derry
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada.,Program in Developmental and Stem Cell Biology, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Mark L Kahn
- Department of Medicine and Cardiovascular Institute, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Douglas A Marchuk
- The Molecular Genetics and Microbiology Department, Duke University Medical Center, Durham, North Carolina, USA
| | - Issam A Awad
- Neurovascular Surgery Program, Section of Neurosurgery, The University of Chicago Medicine and Biological Sciences, Chicago, Illinois, USA
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25
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Hasegawa J, Strunk BS, Weisman LS. PI5P and PI(3,5)P 2: Minor, but Essential Phosphoinositides. Cell Struct Funct 2017; 42:49-60. [PMID: 28302928 DOI: 10.1247/csf.17003] [Citation(s) in RCA: 112] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
In most eukaryotes, phosphoinositides (PIs) have crucial roles in multiple cellular functions. Although the cellular levels of phosphatidylinositol 5-phosphate (PI5P) and phosphatidylinositol 3,5-bisphosphate (PI(3,5)P2) are extremely low relative to some other PIs, emerging evidence demonstrates that both lipids are crucial for the endocytic pathway, intracellular signaling, and adaptation to stress. Mutations that causes defects in the biosynthesis of PI5P and PI(3,5)P2 are linked to human diseases including neurodegenerative disorders. Here, we review recent findings on cellular roles of PI5P and PI(3,5)P2, as well as the pathophysiological importance of these lipids.Key words: Phosphoinositides, Membrane trafficking, Endocytosis, Vacuoles/Lysosomes, Fab1/PIKfyve.
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26
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Priya A, Sugatha J, Parveen S, Lacas-gervais S, Raj P, Gilleron J, Datta S. Essential and selective role of SNX12 in transport of endocytic and retrograde cargo. J Cell Sci 2017; 130:2707-2721. [DOI: 10.1242/jcs.201905] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 07/05/2017] [Indexed: 12/28/2022] Open
Abstract
The endosomal protein sorting machineries play vital roles in diverse physiologically important cellular processes. Much of the core membrane sorting apparatus are conserved in evolution, such as retromer, involved in the recycling of a diverse set of cargoes via retrograde trafficking route. Here, using a RNAi based loss of function study, we identified that SNX12 when suppressed, leads to severe blockage in CIM6PR transport and alters the morphology of the endocytic compartments. We demonstrate that SNX12 is involved in the early phase of CIM6PR transport and mediates receptor recycling upstream of the other well established SNX components of retromer. Ultra-structural analysis revealed that SNX12 resides on tubulo-vesicular structures, inspite of lacking a BAR domain. Further, we illustrate that SNX12 plays a key role in intraluminal vesicle formation and in the maturation of a sub-population of early endosomes to late endosomes thereby regulating selective endocytic transport of cargo for degradation. This study therefore provides evidence for the existence of early endosomal sub-populations, which have differential roles in sorting of the cargoes along endocytic degradative pathways.
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Affiliation(s)
- Amulya Priya
- Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal-462023, India
| | - Jini Sugatha
- Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal-462023, India
| | - Sameena Parveen
- Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal-462023, India
| | - Sandra Lacas-gervais
- Centre Commun de Microscopie Appliquée, Université Nice-Sophia Antipolis, 06108 Nice Cedex 2, France
| | - Prateek Raj
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India
| | - Jérôme Gilleron
- INSERM U1065, Centre Méditerranéen de Médecine Moléculaire C3M, Nice, France
| | - Sunando Datta
- Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal-462023, India
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Marquer C, Tian H, Yi J, Bastien J, Dall'Armi C, Yang-Klingler Y, Zhou B, Chan RB, Di Paolo G. Arf6 controls retromer traffic and intracellular cholesterol distribution via a phosphoinositide-based mechanism. Nat Commun 2016; 7:11919. [PMID: 27336679 PMCID: PMC4931008 DOI: 10.1038/ncomms11919] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Accepted: 05/12/2016] [Indexed: 12/29/2022] Open
Abstract
Small GTPases play a critical role in membrane traffic. Among them, Arf6 mediates transport to and from the plasma membrane, as well as phosphoinositide signalling and cholesterol homeostasis. Here we delineate the molecular basis for the link between Arf6 and cholesterol homeostasis using an inducible knockout (KO) model of mouse embryonic fibroblasts (MEFs). We find that accumulation of free cholesterol in the late endosomes/lysosomes of Arf6 KO MEFs results from mistrafficking of Niemann-Pick type C protein NPC2, a cargo of the cation-independent mannose-6-phosphate receptor (CI-M6PR). This is caused by a selective increase in an endosomal pool of phosphatidylinositol-4-phosphate (PI4P) and a perturbation of retromer, which controls the retrograde transport of CI-M6PR via sorting nexins, including the PI4P effector SNX6. Finally, reducing PI4P levels in KO MEFs through independent mechanisms rescues aberrant retromer tubulation and cholesterol mistrafficking. Our study highlights a phosphoinositide-based mechanism for control of cholesterol distribution via retromer.
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Affiliation(s)
- Catherine Marquer
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York City, New York 10032, USA
| | - Huasong Tian
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York City, New York 10032, USA
| | - Julie Yi
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York City, New York 10032, USA
| | - Jayson Bastien
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York City, New York 10032, USA
| | - Claudia Dall'Armi
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York City, New York 10032, USA
| | - YoungJoo Yang-Klingler
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York City, New York 10032, USA
| | - Bowen Zhou
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York City, New York 10032, USA
| | - Robin Barry Chan
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York City, New York 10032, USA
| | - Gilbert Di Paolo
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York City, New York 10032, USA
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The ML1Nx2 Phosphatidylinositol 3,5-Bisphosphate Probe Shows Poor Selectivity in Cells. PLoS One 2015; 10:e0139957. [PMID: 26460749 PMCID: PMC4604148 DOI: 10.1371/journal.pone.0139957] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Accepted: 09/17/2015] [Indexed: 01/15/2023] Open
Abstract
Phosphatidylinositol (3,5)-bisphosphate (PtdIns(3,5)P2) is a quantitatively minor phospholipid in eukaryotic cells that plays a fundamental role in regulating endocytic membrane traffic. Despite its clear importance for cellular function and organism physiology, mechanistic details of its biology have so far not been fully elucidated. In part, this is due to a lack of experimental tools that specifically probe for PtdIns(3,5)P2 in cells to unambiguously identify its dynamics and site(s) of action. In this study, we have evaluated a recently reported PtdIns(3,5)P2 biosensor, GFP-ML1Nx2, for its veracity as such a probe. We report that, in live cells, the localization of this biosensor to sub-cellular compartments is largely independent of PtdIns(3,5)P2, as assessed after pharmacological, chemical genetic or genomic interventions that block the lipid's synthesis. We therefore conclude that it is unwise to interpret the localization of ML1Nx2 as a true and unbiased biosensor for PtdIns(3,5)P2.
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Maruani A, Huguet G, Beggiato A, ElMaleh M, Toro R, Leblond CS, Mathieu A, Amsellem F, Lemière N, Verloes A, Leboyer M, Gillberg C, Bourgeron T, Delorme R. 11q24.2-25 micro-rearrangements in autism spectrum disorders: Relation to brain structures. Am J Med Genet A 2015; 167A:3019-30. [DOI: 10.1002/ajmg.a.37345] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2015] [Accepted: 08/12/2015] [Indexed: 01/24/2023]
Affiliation(s)
- Anna Maruani
- Human Genetics and Cognitive Functions; Institut Pasteur; Paris France
- CNRS URA 2182; Institut Pasteur; Paris France
- Department of Child Psychiatry; Robert Debré Hospital, APHP; Paris France
| | - Guillaume Huguet
- Human Genetics and Cognitive Functions; Institut Pasteur; Paris France
- CNRS URA 2182; Institut Pasteur; Paris France
| | - Anita Beggiato
- Human Genetics and Cognitive Functions; Institut Pasteur; Paris France
- CNRS URA 2182; Institut Pasteur; Paris France
- Department of Child Psychiatry; Robert Debré Hospital, APHP; Paris France
| | - Monique ElMaleh
- Department of Radiology; Robert Debré Hospital, APHP; Paris France
| | - Roberto Toro
- Human Genetics and Cognitive Functions; Institut Pasteur; Paris France
- CNRS URA 2182; Institut Pasteur; Paris France
| | - Claire S. Leblond
- Human Genetics and Cognitive Functions; Institut Pasteur; Paris France
- CNRS URA 2182; Institut Pasteur; Paris France
| | - Alexandre Mathieu
- Human Genetics and Cognitive Functions; Institut Pasteur; Paris France
- CNRS URA 2182; Institut Pasteur; Paris France
| | | | - Nathalie Lemière
- Human Genetics and Cognitive Functions; Institut Pasteur; Paris France
- CNRS URA 2182; Institut Pasteur; Paris France
| | - Alain Verloes
- Department of Human Genetics; Robert Debré Hospital, APHP; Paris France
| | - Marion Leboyer
- INSERM U955, Team 15; Faculty of Medicine; Creteil France
- Department of Adult Psychiatry; Henri Mondor-Albert Chenevier Hospitals AP-HP; Creteil France
- Fondation FondaMental; French National Science Foundation; Creteil France
| | - Christopher Gillberg
- Gillberg Neuropsychiatry Centre; Gothenburg University; Göteborg Sweden
- Saint George's Hospital Medical School; London United Kingdom
| | - Thomas Bourgeron
- Human Genetics and Cognitive Functions; Institut Pasteur; Paris France
- CNRS URA 2182; Institut Pasteur; Paris France
- Diderot Paris 7; University Paris; Paris France
| | - Richard Delorme
- Human Genetics and Cognitive Functions; Institut Pasteur; Paris France
- CNRS URA 2182; Institut Pasteur; Paris France
- Department of Child Psychiatry; Robert Debré Hospital, APHP; Paris France
- Fondation FondaMental; French National Science Foundation; Creteil France
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30
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Isayenkov SV, Sekan AS, Sorochinsky BV, Blume YB. Molecular aspects of endosomal cellular transport. CYTOL GENET+ 2015. [DOI: 10.3103/s009545271503007x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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31
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Mellado M, Cuartero Y, Brugada R, Verges M. Subcellular localisation of retromer in post-endocytic pathways of polarised Madin-Darby canine kidney cells. Biol Cell 2014; 106:377-93. [PMID: 25081925 DOI: 10.1111/boc.201400011] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Accepted: 07/28/2014] [Indexed: 12/14/2022]
Abstract
BACKGROUND INFORMATION Retromer is required for endosome-to-Golgi retrieval of the cation-independent mannose 6-phosphate receptor (CI-MPR), allowing delivery of hydrolases into lysosomes. It is constituted by a conserved heterotrimer formed by vacuolar protein sorting (Vps) gene products Vps26, Vps35 and Vps29, which is in charge of cargo selection, and a dimer of phosphoinositide-binding sorting nexins (SNXs), which has a structural role. Retromer has been implicated in sorting of additional cargo. Thus, retromer also promotes polymeric immunoglobulin A (pIgA) transcytosis by the pIgA receptor (pIgR) in polarised cells, and considerable evidence implicates retromer in controlling epithelial cell polarity. However, the precise localisation of retromer along the endocytic pathway of polarised cells has not been studied in detail. RESULTS Our biochemical analysis using rat liver endosome fractions suggests a distinct distribution pattern. Although subunits of the cargo-selective complex were enriched in early endosomes (EEs), levels of SNX2 were greater in sorting endosomes. We then immunolocalised the retromer subunits in polarised Madin-Darby canine kidney (MDCK) cells by confocal microscopy. An estimated 25% of total Vps26 and SNX2 localised to EEs, with negligible portions in recycling endosomes as well as in late endosomes and lysosomes. Although Vps26 was in structures of more heterogeneous size and shape than SNX2, these markedly overlapped. In consequence, the two retromer subcomplexes mostly colocalised. When we analysed retromer overlap with its cargo, we found that structures retromer and pIgA(+) are independent of those structures retromer and CI-MPR(+) . Remarkably, retromer localised preferentially at the transcytotic pathway. Pharmacological inhibition of phosphoinositide 3-kinase affected the co-distribution of retromer with pIgA and the CI-MPR, delaying pIgA progress to the apical surface. CONCLUSIONS In polarised MDCK cells, we found retromer associated with certain specialised EE-derived pathways. Our data imply that retromer is largely engaged in pIgA transcytosis in pIgR-expressing MDCK cells, as opposed to endosome-to-Golgi retrieval.
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Affiliation(s)
- Maravillas Mellado
- Laboratory of Epithelial Cell Biology, Príncipe Felipe Research Center (CIPF), Valencia, 46012, Spain
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32
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Kerr M, Teasdale RD. Live imaging of endosome dynamics. Semin Cell Dev Biol 2014; 31:11-9. [PMID: 24704360 DOI: 10.1016/j.semcdb.2014.03.027] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Revised: 03/21/2014] [Accepted: 03/25/2014] [Indexed: 11/26/2022]
Abstract
When studying the living endosome one must first recognise that we are not studying a single discrete organelle but rather a highly dynamic interconnected network of membrane-bound compartments. Endocytosed molecules are sorted and transported through various polymorphic intracellular organelles that mature and interact with one another via fusion and fission events in a highly spatially and temporally co-ordinated manner. As such, we recognise that being a dynamic system, it must be studied in a dynamic fashion. Videomicroscopy has provided profound insights into the cell, and its use in the study of the living endosome has exemplified this supplying a unique perspective on this elusive organelle. In this review we will examine some of the seminal observations that this technology has contributed as well as survey the various assays, tools and technologies that can be applied to understanding the living endosome.
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Affiliation(s)
- Markus Kerr
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Queensland, Australia.
| | - Rohan D Teasdale
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Queensland, Australia
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33
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Differential protein–protein interactions of full length human FasL and FasL fragments generated by proteolysis. Exp Cell Res 2014; 320:290-301. [DOI: 10.1016/j.yexcr.2013.11.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Revised: 10/25/2013] [Accepted: 11/19/2013] [Indexed: 01/14/2023]
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34
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McCartney AJ, Zhang Y, Weisman LS. Phosphatidylinositol 3,5-bisphosphate: low abundance, high significance. Bioessays 2013; 36:52-64. [PMID: 24323921 DOI: 10.1002/bies.201300012] [Citation(s) in RCA: 158] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Recent studies of the low abundant signaling lipid, phosphatidylinositol 3,5-bisphosphate (PI(3,5)P2 ), reveal an intriguingly diverse list of downstream pathways, the intertwined relationship between PI(3,5)P2 and PI5P, as well as links to neurodegenerative diseases. Derived from the structural lipid phosphatidylinositol, PI(3,5)P2 is dynamically generated on multiple cellular compartments where interactions with an increasing list of effectors regulate many cellular pathways. A complex of proteins that includes Fab1/PIKfyve, Vac14, and Fig4/Sac3 mediates the biosynthesis of PI(3,5)P2 , and mutations that disrupt complex function and/or formation cause profound consequences in cells. Surprisingly, mutations in this pathway are linked with neurological diseases, including Charcot-Marie-Tooth syndrome and amyotrophic lateral sclerosis. Future studies of PI(3,5)P2 and PI5P are likely to expand the roles of these lipids in regulation of cellular functions, as well as provide new approaches for treatment of some neurological diseases.
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Affiliation(s)
- Amber J McCartney
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, USA
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35
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Hunt SD, Townley AK, Danson CM, Cullen PJ, Stephens DJ. Microtubule motors mediate endosomal sorting by maintaining functional domain organization. J Cell Sci 2013; 126:2493-501. [PMID: 23549789 PMCID: PMC3679488 DOI: 10.1242/jcs.122317] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Many microtubule motors have been shown to couple to endosomal membranes. These motors include dynein in addition to many different kinesin family members. Sorting nexins (SNXs) are central to the organization and function of endosomes. These proteins can actively shape endosomal membranes and couple directly or indirectly to the minus-end microtubule motor dynein. Motor proteins acting on endosomes drive their motility, dictate their morphology and affect cargo segregation. We have used well-characterized members of the SNX family to elucidate motor coupling using high-resolution light microscopy coupled with depletion of specific microtubule motors. Endosomal domains labelled with SNX1, SNX4 and SNX8 couple to discrete combinations of dynein and kinesin motors. These specific combinations govern the structure and motility of each SNX-coated membrane in addition to the segregation of distinct functional endosomal subdomains. Taken together, our data show that these key features of endosome dynamics are governed by the same set of opposing microtubule motors. Thus, microtubule motors help to define the mosaic layout of endosomes that underpins cargo sorting.
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Affiliation(s)
- Sylvie D Hunt
- Cell Biology Laboratories, School of Biochemistry, Medical Sciences Building, University of Bristol, University Walk, Bristol BS8 1TD, UK
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36
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PtdIns(4)P regulates retromer–motor interaction to facilitate dynein–cargo dissociation at the trans-Golgi network. Nat Cell Biol 2013; 15:417-29. [DOI: 10.1038/ncb2710] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2012] [Accepted: 02/14/2013] [Indexed: 02/08/2023]
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37
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Ogi S, Fujita H, Kashihara M, Yamamoto C, Sonoda K, Okamoto I, Nakagawa K, Ohdo S, Tanaka Y, Kuwano M, Ono M. Sorting nexin 2-mediated membrane trafficking of c-Met contributes to sensitivity of molecular-targeted drugs. Cancer Sci 2013; 104:573-83. [PMID: 23360489 DOI: 10.1111/cas.12117] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2012] [Revised: 01/21/2013] [Accepted: 01/22/2013] [Indexed: 12/20/2022] Open
Abstract
The sorting nexin (SNX) family is a diverse group of cytoplasmic and membrane-associated proteins that are involved in membrane-trafficking steps within the endocytotic network. SNX1 and SNX2 are components of the mammalian retromer complex and they also play critical roles in the membrane trafficking of growth factor receptors including epidermal growth factor receptor (EGFR) and c-Met. The human lung cancer cell lines, which harbor activating mutations in the kinase domain of EGFR gene, are sensitive to EGFR-targeted drugs gefitinib or erlotinib. However, a lung cancer cell line harboring gene amplification of c-Met is sensitive to the c-Met-targeted drug SU11274 but not to EGFR-targeted drugs. C-Met overexpression is identified as one of the bypass mechanisms for acquired resistance to EGFR-targeted drugs. Here we show that the siRNA-mediated knockdown of SNX2 decreases the cell-surface localization of c-Met, but not that of EGFR, resulting in lysosomal degradation of the c-Met protein. SNX2 specifically interacts with c-Met and treatment with lysosomal inhibitors almost completely annihilates downregulation of c-Met protein by SNX2 knockdown. Therefore, silencing of SNX2 markedly alters sensitivity to anticancer drugs targeted to c-Met (SU11274) and EGFR (gefitinib and erlotinib) through promotion of compensatory activation of the EGFR pathway in lung cancer cells. These findings suggest that development of drugs targeting SNX2 could be useful in overcoming drug resistance to EGFR-targeted drugs in lung cancer cells harboring c-Met gene amplification.
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Affiliation(s)
- Sayaka Ogi
- Department of Pharmaceutical Oncology, Kyushu University, Fukuoka, Japan
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38
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Stierhof YD, Viotti C, Scheuring D, Sturm S, Robinson DG. Sorting nexins 1 and 2a locate mainly to the TGN. PROTOPLASMA 2013; 250:235-40. [PMID: 22447127 DOI: 10.1007/s00709-012-0399-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2012] [Accepted: 03/14/2012] [Indexed: 05/26/2023]
Abstract
The subcellular localization of the sorting nexins (SNXs) in higher plants is a matter of controversy. Previous confocal laser scanning microscopy (CLSM studies on root cells from a transgenic Arabidopsis line expressing SNX1-GFP have suggested that this SNX is present on an endosome having characteristics of both the trans-Golgi network (TGN) and the multivesicular body (MVB). In contrast, SNX2a locates exclusively to the TGN when transiently expressed in tobacco mesophyll protoplasts. By performing immunogold electron microscopy on cryofixed Arabidopsis roots, we have tried to clarify the situation. Both SNX1-GFP and endogenous SNX2a locate principally to the TGN. Labeling of MVBs could not be confirmed with any certainty.
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Affiliation(s)
- York-Dieter Stierhof
- Microscopy, Centre for Plant Molecular Biology, University of Tübingen, 72076 Tübingen, Germany
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Abstract
Throughout the animal kingdom, Wnt-triggered signal transduction pathways play fundamental roles in embryonic development and tissue homeostasis. Wnt proteins are modified as glycolipoproteins and are secreted into the extracellular environment as morphogens. Recent studies on the intracellular trafficking of Wnt proteins demonstrate multiple layers of regulation along its secretory pathway. These findings have propelled a great deal of interest among researchers to further investigate the molecular mechanisms that control the release of Wnts and hence the level of Wnt signaling. This review is dedicated to Wntless, a putative G-protein coupled receptor that transports Wnts intracellularly for secretion. Here, we highlight the conclusions drawn from the most recent cellular, molecular and genetic studies that affirm the role of Wntless in the secretion of Wnt proteins.
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40
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Retromer binds the FANSHY sorting motif in SorLA to regulate amyloid precursor protein sorting and processing. J Neurosci 2012; 32:1467-80. [PMID: 22279231 DOI: 10.1523/jneurosci.2272-11.2012] [Citation(s) in RCA: 212] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
sorLA is a sorting receptor for amyloid precursor protein (APP) genetically linked to Alzheimer's disease (AD). Retromer, an adaptor complex in the endosome-to-Golgi retrieval pathway, has been implicated in APP transport because retromer deficiency leads to aberrant APP sorting and processing and levels of retromer proteins are altered in AD. Here we report that sorLA and retromer functionally interact in neurons to control trafficking and amyloidogenic processing of APP. We have identified a sequence (FANSHY) in the cytoplasmic domain of sorLA that is recognized by the VPS26 subunit of the retromer complex. Accordingly, we characterized the interaction between the retromer complex and sorLA and determined the role of retromer on sorLA-dependent sorting and processing of APP. Mutations in the VPS26 binding site resulted in receptor redistribution to the endosomal network, similar to the situation seen in cells with VPS26 knockdown. The sorLA mutant retained APP-binding activity but, as opposed to the wild-type receptor, misdirected APP into a distinct non-Golgi compartment, resulting in increased amyloid processing. In conclusion, our data provide a molecular link between reduced retromer expression and increased amyloidogenesis as seen in patients with sporadic AD.
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41
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Shin HW, Takatsu H, Nakayama K. Mechanisms of membrane curvature generation in membrane traffic. MEMBRANES 2012; 2:118-33. [PMID: 24957965 PMCID: PMC4021884 DOI: 10.3390/membranes2010118] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/29/2012] [Revised: 02/20/2012] [Accepted: 02/21/2012] [Indexed: 11/17/2022]
Abstract
During the vesicular trafficking process, cellular membranes undergo dynamic morphological changes, in particular at the vesicle generation and fusion steps. Changes in membrane shape are regulated by small GTPases, coat proteins and other accessory proteins, such as BAR domain-containing proteins. In addition, membrane deformation entails changes in the lipid composition as well as asymmetric distribution of lipids over the two leaflets of the membrane bilayer. Given that P4-ATPases, which catalyze unidirectional flipping of lipid molecules from the exoplasmic to the cytoplasmic leaflets of the bilayer, are crucial for the trafficking of proteins in the secretory and endocytic pathways, changes in the lipid composition are involved in the vesicular trafficking process. Membrane remodeling is under complex regulation that involves the composition and distribution of lipids as well as assembly of proteins.
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Affiliation(s)
- Hye-Won Shin
- Career-Path Promotion Unit for Young Life Scientists, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan.
| | - Hiroyuki Takatsu
- Career-Path Promotion Unit for Young Life Scientists, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan.
| | - Kazuhisa Nakayama
- Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan.
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Zhang J, Reiling C, Reinecke JB, Prislan I, Marky LA, Sorgen PL, Naslavsky N, Caplan S. Rabankyrin-5 interacts with EHD1 and Vps26 to regulate endocytic trafficking and retromer function. Traffic 2012; 13:745-57. [PMID: 22284051 DOI: 10.1111/j.1600-0854.2012.01334.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2011] [Revised: 01/24/2012] [Accepted: 01/27/2012] [Indexed: 12/13/2022]
Abstract
Rabankyrin-5 (Rank-5) has been implicated as an effector of the small GTPase Rab5 and plays an important role in macropinocytosis. We have now identified Rank-5 as an interaction partner for the recycling regulatory protein, Eps15 homology domain 1 (EHD1). We have demonstrated this interaction by glutathione S-transferase-pulldown, yeast two-hybrid assay, isothermal calorimetry and co-immunoprecipitation, and found that the binding occurs between the EH domain of EHD1 and the NPFED motif of Rank-5. Similar to EHD1, we found that Rank-5 colocalizes and interacts with components of the retromer complex such as vacuolar protein sorting 26 (Vps26), suggesting a role for Rank-5 in retromer-based transport. Indeed, depletion of Rank-5 causes mislocalization of Vps26 and affects both the retrieval of mannose 6-phosphate receptor transport to the Golgi from endosomes and biosynthetic transport. Moreover, Rank-5 is required for normal retromer distribution, as overexpression of a wild-type Rank-5-small interfering RNA-resistant construct rescues retromer mislocalization. Finally, we show that depletion of either Rank-5 or EHD1 impairs secretion of vesicular stomatitis virus glycoprotein. Overall, our data identify a new interaction between Rank-5 and EHD1, and novel endocytic regulatory roles that include retromer-based transport and secretion.
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Affiliation(s)
- Jing Zhang
- Department of Biochemistry and Molecular Biology and Eppley Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198-5870, USA
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43
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Abstract
Endosomes along the degradation pathway exhibit a multivesicular appearance and differ in their lipid compositions. Association of proteins to specific membrane lipids and presumably also lipid-lipid interactions contribute to the formation of functional membrane platforms that regulate endosome biogenesis and function. This chapter provides a brief review of the functions of endosomal lipids in the degradation pathway, a discussion of techniques that allow studying lipid-based mechanisms and a selection of step-by-step protocols for in vivo and in vitro methods commonly used to study lipid roles in endocytosis. The techniques described here have been used to elucidate the function of the late endosomal lipid lysobisphosphatidic acid and allow the monitoring of lipid distribution, levels and dynamics, as well as the characterization of lipid-binding partners.
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44
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Abstract
The endo-lysosomal system is an interconnected tubulo-vesicular network that acts as a sorting station to process and distribute internalised cargo. This network accepts cargoes from both the plasma membrane and the biosynthetic pathway, and directs these cargos either towards the lysosome for degradation, the peri-nuclear recycling endosome for return to the cell surface, or to the trans-Golgi network. These intracellular membranes are variously enriched in different phosphoinositides that help to shape compartmental identity. These lipids act to localise a number of phosphoinositide-binding proteins that function as sorting machineries to regulate endosomal cargo sorting. Herein we discuss regulation of these machineries by phosphoinositides and explore how phosphoinositide-switching contributes toward sorting decisions made at this platform.
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Affiliation(s)
- Peter J Cullen
- Henry Wellcome Integrated Signaling Laboratories, School of Biochemistry, Medical Sciences Building, University of Bristol, BS8 1TD, Bristol, United Kingdom,
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45
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Cullen PJ, Korswagen HC. Sorting nexins provide diversity for retromer-dependent trafficking events. Nat Cell Biol 2011; 14:29-37. [PMID: 22193161 PMCID: PMC3613977 DOI: 10.1038/ncb2374] [Citation(s) in RCA: 277] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Sorting nexins are a large family of evolutionarily conserved phosphoinositide-binding proteins that have fundamental roles in orchestrating cargo sorting through the membranous maze that is the endosomal network. One ancient group of complexes that contain sorting nexins is the retromer. Here we discuss how retromer complexes regulate endosomal sorting, and describe how this is generating exciting new insight into the central role played by endosomal sorting in development and homeostasis of normal tissues.
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Affiliation(s)
- Peter J. Cullen
- Henry Wellcome Integrated Signalling Laboratories, School of Biochemistry, Medical Sciences Building, University Walk, University of Bristol, Bristol BS8 1TD, U.K
| | - Hendrik C. Korswagen
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences and University Medical Center Utrecht, Uppsalalaan 8, 3584 CT, Utrecht, The Netherlands
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46
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Rao Y, Haucke V. Membrane shaping by the Bin/amphiphysin/Rvs (BAR) domain protein superfamily. Cell Mol Life Sci 2011; 68:3983-93. [PMID: 21769645 PMCID: PMC11114942 DOI: 10.1007/s00018-011-0768-5] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2011] [Revised: 06/27/2011] [Accepted: 06/30/2011] [Indexed: 01/27/2023]
Abstract
BAR domain superfamily proteins have emerged as central regulators of dynamic membrane remodeling, thereby playing important roles in a wide variety of cellular processes, such as organelle biogenesis, cell division, cell migration, secretion, and endocytosis. Here, we review the mechanistic and structural basis for the membrane curvature-sensing and deforming properties of BAR domain superfamily proteins. Moreover, we summarize the present state of knowledge with respect to their regulation by autoinhibitory mechanisms or posttranslational modifications, and their interactions with other proteins, in particular with GTPases, and with membrane lipids. We postulate that BAR superfamily proteins act as membrane-deforming scaffolds that spatiotemporally orchestrate membrane remodeling.
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Affiliation(s)
- Yijian Rao
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Takustraße 6, 14195 Berlin, Germany
- Present Address: Max Planck Institute for Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Volker Haucke
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Takustraße 6, 14195 Berlin, Germany
- NeuroCure Cluster of Excellence, Charité Berlin, Charitéplatz 1, 10117 Berlin, Germany
- Leibniz-Institut für Molekulare Pharmakologie (FMP), Robert-Rössle-Straße 10, 13125 Berlin, Germany
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47
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Abstract
From the pioneering work of Mabel and Lowell Hokin in the 1950s, the biology of this specific isomer of hexahydroxycyclohexane and its phosphorylated derivatives, in the form of inositol phosphates and phosphoinositides, has expanded to fill virtually every corner of cell biology, whole-organism physiology and development. In the present paper, I give a personal view of the role played by phosphoinositides in regulating the function of the endosomal network, and, in so doing, highlight some of the basic properties through which phosphoinositides regulate cell function.
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48
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Sharfman M, Bar M, Ehrlich M, Schuster S, Melech-Bonfil S, Ezer R, Sessa G, Avni A. Endosomal signaling of the tomato leucine-rich repeat receptor-like protein LeEix2. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2011; 68:413-23. [PMID: 21736652 DOI: 10.1111/j.1365-313x.2011.04696.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Extracellular leucine-rich repeat (LRR) receptor-like proteins (RLPs) represent a unique class of cell-surface receptors, as they lack a functional cytoplasmic domain. Our knowledge of how RLPs that do not contain a kinase or Toll domain function is very limited. The tomato RLP receptor LeEix2 signals to induce defense responses mediated by the fungal protein ethylene-inducing xylanase (EIX). The movement of FYVE-positive endosomes before and after EIX application was examined using spinning disc confocal microscopy. We found that while FYVE-positive endosomes generally observe a random movement pattern, following EIX application a subpopulation of FYVE-positive endosomes follow a directional movement pattern. Further, cellular endosomes travel greater distances at higher speeds following EIX application. Time-course experiments conducted with specific inhibitors demonstrate the involvement of endosomal signaling in EIX-triggered defense responses. Abolishing the existence of endosomes or the endocytic event prevented EIX-induced signaling. Endocytosis/endosome inhibitors, such as Dynasore or 1-butanol, inhibit EIX-induced signaling. Moreover, treatment with Endosidin1, which inhibits an early step in plasma membrane/endosome trafficking, enhances the induction of defense responses by EIX. Our data indicate a distinct endosomal signaling mechanism for induction of defense responses in this RLP system.
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Affiliation(s)
- Miya Sharfman
- Department of Molecular Biology and Ecology of Plants, Tel-Aviv University, Tel-Aviv, Israel
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49
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Koumandou VL, Klute MJ, Herman EK, Nunez-Miguel R, Dacks JB, Field MC. Evolutionary reconstruction of the retromer complex and its function in Trypanosoma brucei. J Cell Sci 2011; 124:1496-509. [PMID: 21502137 DOI: 10.1242/jcs.081596] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Intracellular trafficking and protein sorting are mediated by various protein complexes, with the retromer complex being primarily involved in retrograde traffic from the endosome or lysosome to the Golgi complex. Here, comparative genomics, cell biology and phylogenetics were used to probe the early evolution of retromer and its function. Retromer subunits Vps26, Vps29 and Vps35 are near universal, and, by inference, the complex was an ancient feature of eukaryotic cells. Surprisingly, we found DSCR3, a Vps26 paralogue in humans associated with Down's syndrome, in at least four eukaryotic supergroups, implying a more ancient origin than previously suspected. By contrast, retromer cargo proteins showed considerable interlineage variability, with lineage-specific and broadly conserved examples found. Vps10 trafficking probably represents an ancestral role for the complex. Vps5, the BAR-domain-containing membrane-deformation subunit, was found in diverse eukaryotes, including in the divergent eukaryote Trypanosoma brucei, where it is the first example of a BAR-domain protein. To determine functional conservation, an initial characterisation of retromer was performed in T. brucei; the endosomal localisation and its role in endosomal targeting are conserved. Therefore retromer is identified as a further feature of the sophisticated intracellular trafficking machinery of the last eukaryotic common ancestor, with BAR domains representing a possible third independent mechanism of membrane-deformation arising in early eukaryotes.
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Affiliation(s)
- V Lila Koumandou
- Department of Pathology, University of Cambridge, Cambridge CB2 1QT, UK
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50
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Scheuring D, Viotti C, Krüger F, Künzl F, Sturm S, Bubeck J, Hillmer S, Frigerio L, Robinson DG, Pimpl P, Schumacher K. Multivesicular bodies mature from the trans-Golgi network/early endosome in Arabidopsis. THE PLANT CELL 2011; 23:3463-81. [PMID: 21934143 PMCID: PMC3203422 DOI: 10.1105/tpc.111.086918] [Citation(s) in RCA: 202] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2011] [Revised: 08/19/2011] [Accepted: 08/31/2011] [Indexed: 05/17/2023]
Abstract
The plant trans-Golgi network/early endosome (TGN/EE) is a major hub for secretory and endocytic trafficking with complex molecular mechanisms controlling sorting and transport of cargo. Vacuolar transport from the TGN/EE to multivesicular bodies/late endosomes (MVBs/LEs) is assumed to occur via clathrin-coated vesicles, although direct proof for their participation is missing. Here, we present evidence that post-TGN transport toward lytic vacuoles occurs independently of clathrin and that MVBs/LEs are derived from the TGN/EE through maturation. We show that the V-ATPase inhibitor concanamycin A significantly reduces the number of MVBs and causes TGN and MVB markers to colocalize in Arabidopsis thaliana roots. Ultrastructural analysis reveals the formation of MVBs from the TGN/EE and their fusion with the vacuole. The localization of the ESCRT components VPS28, VPS22, and VPS2 at the TGN/EE and MVBs/LEs indicates that the formation of intraluminal vesicles starts already at the TGN/EE. Accordingly, a dominant-negative mutant of VPS2 causes TGN and MVB markers to colocalize and blocks vacuolar transport. RNA interference-mediated knockdown of the annexin ANNAT3 also yields the same phenotype. Together, these data indicate that MVBs originate from the TGN/EE in a process that requires the action of ESCRT for the formation of intraluminal vesicles and annexins for the final step of releasing MVBs as a transport carrier to the vacuole.
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Affiliation(s)
- David Scheuring
- Plant Cell Biology, Centre for Organismal Studies, University of Heidelberg, 69120 Heidelberg, Germany
| | - Corrado Viotti
- Developmental Biology of Plants, Centre for Organismal Studies, University of Heidelberg, 69120 Heidelberg, Germany
| | - Falco Krüger
- Plant Cell Biology, Centre for Organismal Studies, University of Heidelberg, 69120 Heidelberg, Germany
| | - Fabian Künzl
- Developmental Genetics, Centre for Plant Molecular Biology, University of Tübingen, 72076 Tuebingen, Germany
| | - Silke Sturm
- Plant Cell Biology, Centre for Organismal Studies, University of Heidelberg, 69120 Heidelberg, Germany
| | - Julia Bubeck
- Developmental Biology of Plants, Centre for Organismal Studies, University of Heidelberg, 69120 Heidelberg, Germany
| | - Stefan Hillmer
- Plant Cell Biology, Centre for Organismal Studies, University of Heidelberg, 69120 Heidelberg, Germany
| | - Lorenzo Frigerio
- Department of Biological Sciences, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - David G. Robinson
- Plant Cell Biology, Centre for Organismal Studies, University of Heidelberg, 69120 Heidelberg, Germany
| | - Peter Pimpl
- Plant Cell Biology, Centre for Organismal Studies, University of Heidelberg, 69120 Heidelberg, Germany
- Developmental Genetics, Centre for Plant Molecular Biology, University of Tübingen, 72076 Tuebingen, Germany
- Address correspondence to
| | - Karin Schumacher
- Developmental Biology of Plants, Centre for Organismal Studies, University of Heidelberg, 69120 Heidelberg, Germany
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