1
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Begley M, Aragon M, Baker RW. A structure-based mechanism for initiation of AP-3 coated vesicle formation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.05.597630. [PMID: 38895279 PMCID: PMC11185636 DOI: 10.1101/2024.06.05.597630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
Adaptor protein complex 3 (AP-3) mediates cargo sorting from endosomes to lysosomes and lysosome-related organelles. Recently, it was shown that AP-3 is in a constitutively open, active conformation compared to the related AP-1 and AP-2 coat complexes, which are inactive until undergoing large conformational changes upon membrane recruitment. How AP-3 is regulated is therefore an open question. To understand the mechanism of AP-3 membrane recruitment and activation, we reconstituted the core of human AP-3 and determined multiple structures in the soluble and membrane-bound states using electron cryo-microscopy (cryo-EM). Similar to yeast AP-3, human AP-3 is in a constitutively open conformation, with the cargo-binding domain of the μ3 subunit conformationally free. To reconstitute AP-3 activation by the small GTPase Arf1, we used lipid nanodiscs to build Arf1-AP-3 complexes on membranes and determined three structures that show the stepwise conformational changes required for formation of AP-3 coated vesicles. First, membrane-recruitment is driven by one of two predicted Arf1 binding sites on AP-3. In this conformation, AP-3 is flexibly tethered to the membrane and its cargo binding domain remains conformationally dynamic. Second, cargo binding causes AP-3 to adopt a fixed position and rigidifies the complex, which stabilizes binding for a second Arf1 molecule. Finally, binding of the second Arf1 molecule provides the template for AP-3 dimerization, providing a glimpse into the first step of coat polymerization. We propose coat polymerization only occurs after cargo engagement, thereby linking cargo sorting with assembly of higher order coat structures. Additionally, we provide evidence for two amphipathic helices in AP-3, suggesting that AP-3 contributes to membrane deformation during coat assembly. In total, these data provide evidence for the first stages of AP-3 mediated vesicle coat assembly.
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Affiliation(s)
- Matthew Begley
- Department of Biochemistry and Biophysics, UNC Chapel Hill School of Medicine; Chapel Hill, NC 27516, USA
| | - Mahira Aragon
- New York Structural Biology Center; New York, NY 10027, USA
| | - Richard W. Baker
- Department of Biochemistry and Biophysics, UNC Chapel Hill School of Medicine; Chapel Hill, NC 27516, USA
- UNC Lineberger Comprehensive Cancer Center. UNC Chapel Hill School of Medicine; Chapel Hill, NC 27516, USA
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2
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Schoppe J, Schubert E, Apelbaum A, Yavavli E, Birkholz O, Stephanowitz H, Han Y, Perz A, Hofnagel O, Liu F, Piehler J, Raunser S, Ungermann C. Flexible open conformation of the AP-3 complex explains its role in cargo recruitment at the Golgi. J Biol Chem 2021; 297:101334. [PMID: 34688652 PMCID: PMC8591511 DOI: 10.1016/j.jbc.2021.101334] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 09/15/2021] [Accepted: 09/21/2021] [Indexed: 01/17/2023] Open
Abstract
Vesicle formation at endomembranes requires the selective concentration of cargo by coat proteins. Conserved adapter protein complexes at the Golgi (AP-3), the endosome (AP-1), or the plasma membrane (AP-2) with their conserved core domain and flexible ear domains mediate this function. These complexes also rely on the small GTPase Arf1 and/or specific phosphoinositides for membrane binding. The structural details that influence these processes, however, are still poorly understood. Here we present cryo-EM structures of the full-length stable 300 kDa yeast AP-3 complex. The structures reveal that AP-3 adopts an open conformation in solution, comparable to the membrane-bound conformations of AP-1 or AP-2. This open conformation appears to be far more flexible than AP-1 or AP-2, resulting in compact, intermediate, and stretched subconformations. Mass spectrometrical analysis of the cross-linked AP-3 complex further indicates that the ear domains are flexibly attached to the surface of the complex. Using biochemical reconstitution assays, we also show that efficient AP-3 recruitment to the membrane depends primarily on cargo binding. Once bound to cargo, AP-3 clustered and immobilized cargo molecules, as revealed by single-molecule imaging on polymer-supported membranes. We conclude that its flexible open state may enable AP-3 to bind and collect cargo at the Golgi and could thus allow coordinated vesicle formation at the trans-Golgi upon Arf1 activation.
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Affiliation(s)
- Jannis Schoppe
- Department of Biology/Chemistry, Biochemistry Section, Osnabrück University, Osnabrück, Germany
| | - Evelyn Schubert
- Department of Structural Biochemistry, Max-Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Amir Apelbaum
- Department of Structural Biochemistry, Max-Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Erdal Yavavli
- Department of Biology/Chemistry, Biochemistry Section, Osnabrück University, Osnabrück, Germany
| | - Oliver Birkholz
- Department of Biology/Chemistry, Biophysics Section, Osnabrück University, Osnabrück, Germany
| | - Heike Stephanowitz
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Campus Berlin-Buch, Berlin, Germany
| | - Yaping Han
- Department of Biology/Chemistry, Biochemistry Section, Osnabrück University, Osnabrück, Germany
| | - Angela Perz
- Department of Biology/Chemistry, Biochemistry Section, Osnabrück University, Osnabrück, Germany
| | - Oliver Hofnagel
- Department of Structural Biochemistry, Max-Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Fan Liu
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Campus Berlin-Buch, Berlin, Germany
| | - Jacob Piehler
- Department of Biology/Chemistry, Biophysics Section, Osnabrück University, Osnabrück, Germany; Center of Cellular Nanoanalytics Osnabrück (CellNanOs), Osnabrück University, Osnabrück, Germany
| | - Stefan Raunser
- Department of Structural Biochemistry, Max-Planck Institute of Molecular Physiology, Dortmund, Germany.
| | - Christian Ungermann
- Department of Biology/Chemistry, Biochemistry Section, Osnabrück University, Osnabrück, Germany; Center of Cellular Nanoanalytics Osnabrück (CellNanOs), Osnabrück University, Osnabrück, Germany.
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3
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Bowman SL, Le L, Zhu Y, Harper DC, Sitaram A, Theos AC, Sviderskaya EV, Bennett DC, Raposo-Benedetti G, Owen DJ, Dennis MK, Marks MS. A BLOC-1-AP-3 super-complex sorts a cis-SNARE complex into endosome-derived tubular transport carriers. J Cell Biol 2021; 220:212016. [PMID: 33886957 PMCID: PMC8077166 DOI: 10.1083/jcb.202005173] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2020] [Revised: 02/15/2021] [Accepted: 03/19/2021] [Indexed: 02/02/2023] Open
Abstract
Membrane transport carriers fuse with target membranes through engagement of cognate vSNAREs and tSNAREs on each membrane. How vSNAREs are sorted into transport carriers is incompletely understood. Here we show that VAMP7, the vSNARE for fusing endosome-derived tubular transport carriers with maturing melanosomes in melanocytes, is sorted into transport carriers in complex with the tSNARE component STX13. Sorting requires either recognition of VAMP7 by the AP-3δ subunit of AP-3 or of STX13 by the pallidin subunit of BLOC-1, but not both. Consequently, melanocytes expressing both AP-3δ and pallidin variants that cannot bind their respective SNARE proteins are hypopigmented and fail to sort BLOC-1-dependent cargo, STX13, or VAMP7 into transport carriers. However, SNARE binding does not influence BLOC-1 function in generating tubular transport carriers. These data reveal a novel mechanism of vSNARE sorting by recognition of redundant sorting determinants on a SNARE complex by an AP-3-BLOC-1 super-complex.
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Affiliation(s)
- Shanna L. Bowman
- Department of Pathology & Laboratory Medicine, Children's Hospital of Philadelphia Research Institute, Philadelphia, PA,Department of Pathology & Laboratory Medicine, University of Pennsylvania, Philadelphia, PA,Department of Physiology, University of Pennsylvania, Philadelphia, PA,Department of Biology, Linfield University, McMinnville, OR
| | - Linh Le
- Department of Pathology & Laboratory Medicine, Children's Hospital of Philadelphia Research Institute, Philadelphia, PA,Department of Pathology & Laboratory Medicine, University of Pennsylvania, Philadelphia, PA,Department of Physiology, University of Pennsylvania, Philadelphia, PA,Cell and Molecular Biology Graduate Group, University of Pennsylvania, Philadelphia, PA
| | - Yueyao Zhu
- Department of Pathology & Laboratory Medicine, Children's Hospital of Philadelphia Research Institute, Philadelphia, PA,Department of Pathology & Laboratory Medicine, University of Pennsylvania, Philadelphia, PA,Department of Physiology, University of Pennsylvania, Philadelphia, PA,Department of Biology, University of Pennsylvania, Philadelphia, PA
| | - Dawn C. Harper
- Department of Pathology & Laboratory Medicine, Children's Hospital of Philadelphia Research Institute, Philadelphia, PA,Department of Pathology & Laboratory Medicine, University of Pennsylvania, Philadelphia, PA,Department of Physiology, University of Pennsylvania, Philadelphia, PA
| | - Anand Sitaram
- Department of Pathology & Laboratory Medicine, Children's Hospital of Philadelphia Research Institute, Philadelphia, PA,Department of Pathology & Laboratory Medicine, University of Pennsylvania, Philadelphia, PA,Department of Physiology, University of Pennsylvania, Philadelphia, PA
| | | | - Elena V. Sviderskaya
- Cell Biology Research Centre, Molecular and Clinical Sciences Research Institute, St George's, University of London, London, UK
| | - Dorothy C. Bennett
- Cell Biology Research Centre, Molecular and Clinical Sciences Research Institute, St George's, University of London, London, UK
| | - Graça Raposo-Benedetti
- Institut Curie, Paris Sciences et Lettres Research University, Centre National de la Recherche Scientifique Unité Mixte de Recherche 144, Compartiments de Structure et de Membrane, Paris, France
| | - David J. Owen
- Cambridge Institute for Medical Research, Cambridge, UK
| | - Megan K. Dennis
- Department of Pathology & Laboratory Medicine, Children's Hospital of Philadelphia Research Institute, Philadelphia, PA,Department of Pathology & Laboratory Medicine, University of Pennsylvania, Philadelphia, PA,Department of Physiology, University of Pennsylvania, Philadelphia, PA,Department of Biology, Marist College, Poughkeepsie, NY
| | - Michael S. Marks
- Department of Pathology & Laboratory Medicine, Children's Hospital of Philadelphia Research Institute, Philadelphia, PA,Department of Pathology & Laboratory Medicine, University of Pennsylvania, Philadelphia, PA,Department of Physiology, University of Pennsylvania, Philadelphia, PA,Correspondence to Michael S. Marks:
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4
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Schoppe J, Mari M, Yavavli E, Auffarth K, Cabrera M, Walter S, Fröhlich F, Ungermann C. AP-3 vesicle uncoating occurs after HOPS-dependent vacuole tethering. EMBO J 2020; 39:e105117. [PMID: 32840906 PMCID: PMC7560216 DOI: 10.15252/embj.2020105117] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 07/16/2020] [Accepted: 07/22/2020] [Indexed: 11/09/2022] Open
Abstract
Heterotetrameric adapter (AP) complexes cooperate with the small GTPase Arf1 or lipids in cargo selection, vesicle formation, and budding at endomembranes in eukaryotic cells. While most AP complexes also require clathrin as the outer vesicle shell, formation of AP-3-coated vesicles involved in Golgi-to-vacuole transport in yeast has been postulated to depend on Vps41, a subunit of the vacuolar HOPS tethering complex. HOPS has also been identified as the tether of AP-3 vesicles on vacuoles. To unravel this conundrum of a dual Vps41 function, we anchored Vps41 stably to the mitochondrial outer membrane. By monitoring AP-3 recruitment, we now show that Vps41 can tether AP-3 vesicles to mitochondria, yet AP-3 vesicles can form in the absence of Vps41 or clathrin. By proximity labeling and mass spectrometry, we identify the Arf1 GTPase-activating protein (GAP) Age2 at the AP-3 coat and show that tethering, but not fusion at the vacuole can occur without complete uncoating. We conclude that AP-3 vesicles retain their coat after budding and that their complete uncoating occurs only after tethering at the vacuole.
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Affiliation(s)
- Jannis Schoppe
- Department of Biology/Chemistry, Biochemistry Section, University of Osnabrück, Osnabrück, Germany
| | - Muriel Mari
- Department of Biomedical Sciences of Cells and Systems, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Erdal Yavavli
- Department of Biology/Chemistry, Biochemistry Section, University of Osnabrück, Osnabrück, Germany
| | - Kathrin Auffarth
- Department of Biology/Chemistry, Biochemistry Section, University of Osnabrück, Osnabrück, Germany
| | - Margarita Cabrera
- Departament de Ciències Experimentals i de la Salut, Universitat Pompeu Farba, Barcelona, Spain
| | - Stefan Walter
- Center of Cellular Nanoanalytic Osnabrück (CellNanOs), University of Osnabrück, Osnabrück, Germany
| | - Florian Fröhlich
- Center of Cellular Nanoanalytic Osnabrück (CellNanOs), University of Osnabrück, Osnabrück, Germany.,Department of Biology/Chemistry, Molecular Membrane Biology Section, University of Osnabrück, Osnabrück, Germany
| | - Christian Ungermann
- Department of Biology/Chemistry, Biochemistry Section, University of Osnabrück, Osnabrück, Germany.,Center of Cellular Nanoanalytic Osnabrück (CellNanOs), University of Osnabrück, Osnabrück, Germany
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5
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Bowman SL, Bi-Karchin J, Le L, Marks MS. The road to lysosome-related organelles: Insights from Hermansky-Pudlak syndrome and other rare diseases. Traffic 2020; 20:404-435. [PMID: 30945407 DOI: 10.1111/tra.12646] [Citation(s) in RCA: 120] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 04/02/2019] [Accepted: 04/02/2019] [Indexed: 12/11/2022]
Abstract
Lysosome-related organelles (LROs) comprise a diverse group of cell type-specific, membrane-bound subcellular organelles that derive at least in part from the endolysosomal system but that have unique contents, morphologies and functions to support specific physiological roles. They include: melanosomes that provide pigment to our eyes and skin; alpha and dense granules in platelets, and lytic granules in cytotoxic T cells and natural killer cells, which release effectors to regulate hemostasis and immunity; and distinct classes of lamellar bodies in lung epithelial cells and keratinocytes that support lung plasticity and skin lubrication. The formation, maturation and/or secretion of subsets of LROs are dysfunctional or entirely absent in a number of hereditary syndromic disorders, including in particular the Hermansky-Pudlak syndromes. This review provides a comprehensive overview of LROs in humans and model organisms and presents our current understanding of how the products of genes that are defective in heritable diseases impact their formation, motility and ultimate secretion.
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Affiliation(s)
- Shanna L Bowman
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia Research Institute, Philadelphia, Pennsylvania.,Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.,Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Jing Bi-Karchin
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia Research Institute, Philadelphia, Pennsylvania.,Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.,Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Linh Le
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia Research Institute, Philadelphia, Pennsylvania.,Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.,Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.,Cell and Molecular Biology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Michael S Marks
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia Research Institute, Philadelphia, Pennsylvania.,Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.,Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
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6
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Abstract
Protein coats are supramolecular complexes that assemble on the cytosolic face of membranes to promote cargo sorting and transport carrier formation in the endomembrane system of eukaryotic cells. Several types of protein coats have been described, including COPI, COPII, AP-1, AP-2, AP-3, AP-4, AP-5, and retromer, which operate at different stages of the endomembrane system. Defects in these coats impair specific transport pathways, compromising the function and viability of the cells. In humans, mutations in subunits of these coats cause various congenital diseases that are collectively referred to as coatopathies. In this article, we review the fundamental properties of protein coats and the diseases that result from mutation of their constituent subunits.
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Affiliation(s)
- Esteban C Dell'Angelica
- Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, California 90095, USA
| | - Juan S Bonifacino
- Cell Biology and Neurobiology Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health, Bethesda, Maryland 20892, USA;
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7
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Hunter EL, Lechtreck K, Fu G, Hwang J, Lin H, Gokhale A, Alford LM, Lewis B, Yamamoto R, Kamiya R, Yang F, Nicastro D, Dutcher SK, Wirschell M, Sale WS. The IDA3 adapter, required for intraflagellar transport of I1 dynein, is regulated by ciliary length. Mol Biol Cell 2018; 29:886-896. [PMID: 29467251 PMCID: PMC5896928 DOI: 10.1091/mbc.e17-12-0729] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 02/09/2018] [Accepted: 02/16/2018] [Indexed: 11/18/2022] Open
Abstract
We determined how the ciliary motor I1 dynein is transported. A specialized adapter, IDA3, facilitates I1 dynein attachment to the ciliary transporter called intraflagellar transport (IFT). Loading of IDA3 and I1 dynein on IFT is regulated by ciliary length.
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Affiliation(s)
- Emily L. Hunter
- Department of Cell Biology, Emory University, Atlanta, GA 30322
| | - Karl Lechtreck
- Department of Cellular Biology, University of Georgia, Athens, GA 30602
| | - Gang Fu
- Departments of Cell Biology and Biophysics, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Juyeon Hwang
- Department of Cell Biology, Emory University, Atlanta, GA 30322
| | - Huawen Lin
- Department of Genetics, Washington University School of Medicine, St. Louis, MO 63110
| | - Avanti Gokhale
- Department of Cell Biology, Emory University, Atlanta, GA 30322
| | - Lea M. Alford
- Department of Biology, Oglethorpe University, Atlanta, GA 30319
| | - Brian Lewis
- Department of Genetics, Washington University School of Medicine, St. Louis, MO 63110
| | - Ryosuke Yamamoto
- Department of Biological Sciences, Osaka University, Osaka 560-0043, Japan
| | - Ritsu Kamiya
- Department of Biological Sciences, Chuo University, Tokyo 112-8551, Japan
| | - Fan Yang
- Department of Biochemistry, University of Mississippi Medical Center, Jackson, MS 39216
| | - Daniela Nicastro
- Departments of Cell Biology and Biophysics, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Susan K. Dutcher
- Department of Genetics, Washington University School of Medicine, St. Louis, MO 63110
| | - Maureen Wirschell
- Department of Biochemistry, University of Mississippi Medical Center, Jackson, MS 39216
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8
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Zlatic SA, Vrailas-Mortimer A, Gokhale A, Carey LJ, Scott E, Burch R, McCall MM, Rudin-Rush S, Davis JB, Hartwig C, Werner E, Li L, Petris M, Faundez V. Rare Disease Mechanisms Identified by Genealogical Proteomics of Copper Homeostasis Mutant Pedigrees. Cell Syst 2018; 6:368-380.e6. [PMID: 29397366 DOI: 10.1016/j.cels.2018.01.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 10/28/2017] [Accepted: 01/05/2018] [Indexed: 12/22/2022]
Abstract
Rare neurological diseases shed light onto universal neurobiological processes. However, molecular mechanisms connecting genetic defects to their disease phenotypes are elusive. Here, we obtain mechanistic information by comparing proteomes of cells from individuals with rare disorders with proteomes from their disease-free consanguineous relatives. We use triple-SILAC mass spectrometry to quantify proteomes from human pedigrees affected by mutations in ATP7A, which cause Menkes disease, a rare neurodegenerative and neurodevelopmental disorder stemming from systemic copper depletion. We identified 214 proteins whose expression was altered in ATP7A-/y fibroblasts. Bioinformatic analysis of ATP7A-mutant proteomes identified known phenotypes and processes affected in rare genetic diseases causing copper dyshomeostasis, including altered mitochondrial function. We found connections between copper dyshomeostasis and the UCHL1/PARK5 pathway of Parkinson disease, which we validated with mitochondrial respiration and Drosophila genetics assays. We propose that our genealogical "omics" strategy can be broadly applied to identify mechanisms linking a genomic locus to its phenotypes.
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Affiliation(s)
| | - Alysia Vrailas-Mortimer
- School of Biological Sciences Illinois State University, Normal, IL 617901, USA; University of Denver, Department of Biological Sciences, Denver, CO 80208, USA
| | - Avanti Gokhale
- Department of Cell Biology, Emory University, Atlanta, GA 30322, USA
| | - Lucas J Carey
- School of Biological Sciences Illinois State University, Normal, IL 617901, USA
| | - Elizabeth Scott
- School of Biological Sciences Illinois State University, Normal, IL 617901, USA
| | - Reid Burch
- School of Biological Sciences Illinois State University, Normal, IL 617901, USA; University of Denver, Department of Biological Sciences, Denver, CO 80208, USA
| | - Morgan M McCall
- School of Biological Sciences Illinois State University, Normal, IL 617901, USA
| | | | | | - Cortnie Hartwig
- Department of Cell Biology, Emory University, Atlanta, GA 30322, USA; Department of Chemistry, Agnes Scott College, Decatur, GA 30030, USA
| | - Erica Werner
- Department of Biochemistry, Emory University, Atlanta, GA 30322, USA
| | - Lian Li
- Department of Pharmacology, Emory University, Atlanta, GA 30322, USA
| | - Michael Petris
- Department of Biochemistry, University of Missouri, Columbia, MO 65211, USA
| | - Victor Faundez
- Department of Cell Biology, Emory University, Atlanta, GA 30322, USA.
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9
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Day KJ, Casler JC, Glick BS. Budding Yeast Has a Minimal Endomembrane System. Dev Cell 2018; 44:56-72.e4. [PMID: 29316441 DOI: 10.1016/j.devcel.2017.12.014] [Citation(s) in RCA: 106] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Revised: 12/01/2017] [Accepted: 12/12/2017] [Indexed: 12/13/2022]
Abstract
The endomembrane system consists of the secretory and endocytic pathways, which communicate by transport to and from the trans-Golgi network (TGN). In mammalian cells, the endocytic pathway includes early, late, and recycling endosomes. In budding yeast, different types of endosomes have been described, but the organization of the endocytic pathway has remained unclear. We performed a spatial and temporal analysis of yeast endosomal markers and endocytic cargoes. Our results indicate that the yeast TGN also serves as an early and recycling endosome. In addition, as previously described, yeast contains a late or prevacuolar endosome (PVE). Endocytic cargoes localize to the TGN shortly after internalization, and manipulations that perturb export from the TGN can slow the passage of endocytic cargoes to the PVE. Yeast apparently lacks a distinct early endosome. Thus, yeast has a simple endocytic pathway that may reflect the ancestral organization of the endomembrane system.
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Affiliation(s)
- Kasey J Day
- Department of Molecular Genetics and Cell Biology, University of Chicago, 920 East 58th Street, Chicago, IL 60637, USA
| | - Jason C Casler
- Department of Molecular Genetics and Cell Biology, University of Chicago, 920 East 58th Street, Chicago, IL 60637, USA
| | - Benjamin S Glick
- Department of Molecular Genetics and Cell Biology, University of Chicago, 920 East 58th Street, Chicago, IL 60637, USA.
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10
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Wood LA, Larocque G, Clarke NI, Sarkar S, Royle SJ. New tools for "hot-wiring" clathrin-mediated endocytosis with temporal and spatial precision. J Cell Biol 2017; 216:4351-4365. [PMID: 28954824 PMCID: PMC5716275 DOI: 10.1083/jcb.201702188] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Revised: 07/26/2017] [Accepted: 08/25/2017] [Indexed: 12/16/2022] Open
Abstract
Clathrin-mediated endocytosis (CME) is the major route of receptor internalization at the plasma membrane. Analysis of constitutive CME is difficult because the initiation of endocytic events is unpredictable. When and where a clathrin-coated pit will form and what cargo it will contain are difficult to foresee. Here we describe a series of genetically encoded reporters that allow the initiation of CME on demand. A clathrin-binding protein fragment ("hook") is inducibly attached to an "anchor" protein at the plasma membrane, which triggers the formation of new clathrin-coated vesicles. Our design incorporates temporal and spatial control by the use of chemical and optogenetic methods for inducing hook-anchor attachment. Moreover, the cargo is defined. Because several steps in vesicle creation are bypassed, we term it "hot-wiring." We use hot-wired endocytosis to describe the functional interactions between clathrin and AP2. Two distinct sites on the β2 subunit, one on the hinge and the other on the appendage, are necessary and sufficient for functional clathrin engagement.
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Affiliation(s)
- Laura A Wood
- Centre for Mechanochemical Cell Biology, Warwick Medical School, University of Warwick, Coventry, England, UK
| | - Gabrielle Larocque
- Centre for Mechanochemical Cell Biology, Warwick Medical School, University of Warwick, Coventry, England, UK
| | - Nicholas I Clarke
- Centre for Mechanochemical Cell Biology, Warwick Medical School, University of Warwick, Coventry, England, UK
| | - Sourav Sarkar
- Centre for Mechanochemical Cell Biology, Warwick Medical School, University of Warwick, Coventry, England, UK
| | - Stephen J Royle
- Centre for Mechanochemical Cell Biology, Warwick Medical School, University of Warwick, Coventry, England, UK
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11
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Sahu BS, Manna PT, Edgar JR, Antrobus R, Mahata SK, Bartolomucci A, Borner GHH, Robinson MS. Role of clathrin in dense core vesicle biogenesis. Mol Biol Cell 2017; 28:2676-2685. [PMID: 28814506 PMCID: PMC5620375 DOI: 10.1091/mbc.e16-10-0742] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Revised: 07/13/2017] [Accepted: 08/07/2017] [Indexed: 11/11/2022] Open
Abstract
The dense core vesicles (DCVs) of neuroendocrine cells are a rich source of bioactive molecules such as peptides, hormones, and neurotransmitters, but relatively little is known about how they are formed. Using fractionation profiling, a method that combines subcellular fractionation with mass spectrometry, we identified ∼1200 proteins in PC12 cell vesicle-enriched fractions, with DCV-associated proteins showing distinct profiles from proteins associated with other types of vesicles. To investigate the role of clathrin in DCV biogenesis, we stably transduced PC12 cells with an inducible short hairpin RNA targeting clathrin heavy chain, resulting in ∼85% protein loss. DCVs could still be observed in the cells by electron microscopy, but mature profiles were approximately fourfold less abundant than in mock-treated cells. By quantitative mass spectrometry, DCV-associated proteins were found to be reduced approximately twofold in clathrin-depleted cells as a whole and approximately fivefold in vesicle-enriched fractions. Our combined data sets enabled us to identify new candidate DCV components. Secretion assays revealed that clathrin depletion causes a near-complete block in secretagogue-induced exocytosis. Taken together, our data indicate that clathrin has a function in DCV biogenesis beyond its established role in removing unwanted proteins from the immature vesicle.
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Affiliation(s)
- Bhavani S Sahu
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, United Kingdom
| | - Paul T Manna
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, United Kingdom
| | - James R Edgar
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, United Kingdom
| | - Robin Antrobus
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, United Kingdom
| | - Sushil K Mahata
- Department of Medicine, Veterans Affairs San Diego Healthcare System, San Diego, CA 92161.,Department of Medicine, University of California, San Diego, La Jolla, CA 92093
| | - Alessandro Bartolomucci
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN 55455
| | - Georg H H Borner
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, United Kingdom
| | - Margaret S Robinson
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, United Kingdom
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Abstract
Dysbindin is a schizophrenia susceptibility factor and subunit of the biogenesis of lysosome-related organelles complex 1 (BLOC-1) required for lysosome-related organelle biogenesis, and in neurons, synaptic vesicle assembly, neurotransmission, and plasticity. Protein networks, or interactomes, downstream of dysbindin/BLOC-1 remain partially explored despite their potential to illuminate neurodevelopmental disorder mechanisms. Here, we conducted a proteome-wide search for polypeptides whose cellular content is sensitive to dysbindin/BLOC-1 loss of function. We identified components of the vesicle fusion machinery as factors downregulated in dysbindin/BLOC-1 deficiency in neuroectodermal cells and iPSC-derived human neurons, among them the N-ethylmaleimide-sensitive factor (NSF). Human dysbindin/BLOC-1 coprecipitates with NSF and vice versa, and both proteins colocalized in a Drosophila model synapse. To test the hypothesis that NSF and dysbindin/BLOC-1 participate in a pathway-regulating synaptic function, we examined the role for NSF in dysbindin/BLOC-1-dependent synaptic homeostatic plasticity in Drosophila. As previously described, we found that mutations in dysbindin precluded homeostatic synaptic plasticity elicited by acute blockage of postsynaptic receptors. This dysbindin mutant phenotype is fully rescued by presynaptic expression of either dysbindin or Drosophila NSF. However, neither reduction of NSF alone or in combination with dysbindin haploinsufficiency impaired homeostatic synaptic plasticity. Our results demonstrate that dysbindin/BLOC-1 expression defects result in altered cellular content of proteins of the vesicle fusion apparatus and therefore influence synaptic plasticity.
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13
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Bekier ME, Mazur T, Rashid MS, Taylor WR. Borealin dimerization mediates optimal CPC checkpoint function by enhancing localization to centromeres and kinetochores. Nat Commun 2015; 6:6775. [PMID: 25854549 PMCID: PMC4392389 DOI: 10.1038/ncomms7775] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 02/26/2015] [Indexed: 12/21/2022] Open
Abstract
The Chromosomal Passenger Complex (CPC) localizes to centromeres where it activates the mitotic checkpoint in response to inappropriate inter-kinetochore tension. This error correction function is essential for proper chromosome segregation. Here we define several critical features of CPC localization and function. First, the Borealin dimerization domain suppresses dynamic exchange at the centromere to allow optimal CPC function. Second, Borealin dimerization is essential to target a subpopulation of CPC proximal to the kinetochore when the mitotic spindle is disrupted. This subpopulation is also needed for full CPC checkpoint function. The existence of a pool of CPC at the kinetochore suggests that error correction is more complicated than predicted from the Aurora B phosphorylation gradient model. Finally, Haspin kinase plays a key role in maintaining the slowly exchanging centromere Borealin pool, while Aurora B and Mps1 play minimal roles in maintaining CPC localization once cells are in mitosis.
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Affiliation(s)
- Michael E Bekier
- Department of Biological Sciences, University of Toledo, 2801 West Bancroft Street, MS 601, Toledo, Ohio 43606, USA
| | - Travis Mazur
- Department of Biological Sciences, University of Toledo, 2801 West Bancroft Street, MS 601, Toledo, Ohio 43606, USA
| | - Maisha S Rashid
- Department of Biological Sciences, University of Toledo, 2801 West Bancroft Street, MS 601, Toledo, Ohio 43606, USA
| | - William R Taylor
- Department of Biological Sciences, University of Toledo, 2801 West Bancroft Street, MS 601, Toledo, Ohio 43606, USA
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14
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Waugh MG. PIPs in neurological diseases. Biochim Biophys Acta Mol Cell Biol Lipids 2015; 1851:1066-82. [PMID: 25680866 DOI: 10.1016/j.bbalip.2015.02.002] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Revised: 01/29/2015] [Accepted: 02/01/2015] [Indexed: 12/19/2022]
Abstract
Phosphoinositide (PIP) lipids regulate many aspects of cell function in the nervous system including receptor signalling, secretion, endocytosis, migration and survival. Levels of PIPs such as PI4P, PI(4,5)P2 and PI(3,4,5)P3 are normally tightly regulated by phosphoinositide kinases and phosphatases. Deregulation of these biochemical pathways leads to lipid imbalances, usually on intracellular endosomal membranes, and these changes have been linked to a number of major neurological diseases including Alzheimer's, Parkinson's, epilepsy, stroke, cancer and a range of rarer inherited disorders including brain overgrowth syndromes, Charcot-Marie-Tooth neuropathies and neurodevelopmental conditions such as Lowe's syndrome. This article analyses recent progress in this area and explains how PIP lipids are involved, to varying degrees, in almost every class of neurological disease. This article is part of a Special Issue entitled Brain Lipids.
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Affiliation(s)
- Mark G Waugh
- Lipid and Membrane Biology Group, Institute for Liver and Digestive Health, UCL, Royal Free Campus, Rowland Hill Street, London NW3 2PF, United Kingdom.
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15
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Kokotos AC, Cousin MA. Synaptic vesicle generation from central nerve terminal endosomes. Traffic 2014; 16:229-40. [PMID: 25346420 DOI: 10.1111/tra.12235] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Revised: 10/15/2014] [Accepted: 10/20/2014] [Indexed: 01/01/2023]
Abstract
Central nerve terminals contain a small number of synaptic vesicles (SVs) that must sustain the fidelity of neurotransmission across a wide range of stimulation intensities. For this to be achieved, nerve terminals integrate a number of complementary endocytosis modes whose activation spans the breadth of these neuronal stimulation patterns. Two such modes are ultrafast endocytosis and activity-dependent bulk endocytosis, which are triggered by stimuli at either end of the physiological range. Both endocytosis modes generate endosomes directly from the nerve terminal plasma membrane, before the subsequent production of SVs from these structures. This review will discuss the current knowledge relating to the molecular mechanisms involved in the generation of SVs from nerve terminal endosomes, how this relates to other mechanisms of SV production and the functional role of such SVs.
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Affiliation(s)
- Alexandros C Kokotos
- Centre for Integrative Physiology, George Square, University of Edinburgh, Edinburgh, EH8 9XD, UK
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16
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Barlow LD, Dacks JB, Wideman JG. From all to (nearly) none: Tracing adaptin evolution in Fungi. CELLULAR LOGISTICS 2014; 4:e28114. [PMID: 24843829 PMCID: PMC4022609 DOI: 10.4161/cl.28114] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Revised: 02/03/2014] [Accepted: 02/04/2014] [Indexed: 11/19/2022]
Abstract
The five adaptor protein (AP) complexes function in cargo-selection and coat-recruitment stages of vesicular transport in eukaryotic cells. Much of what we know about AP complex function has come from experimental work using Saccharomyces cerevisiae as a model. Here, using a combination of comparative genomic and phylogenetic approaches we provide evolutionary context for the knowledge gained from this model system by searching the genomes of diverse fungi as well as a member of the sister group to all fungi, Fonticula alba, for presence of AP subunits. First, we demonstrate that F. alba contains all five AP complexes; whereas, similar to S. cerevisiae, most fungi retain only AP-1 to 3. As exceptions, the glomeromycete Rhizophagus irregularis maintains a complete AP-4 and chytrid fungi Spizellomyces punctatus and Batrachochytrium dendrobatidis retain partial AP-4 complexes. The presence of AP-4 subunits in diverse fungi suggests that AP-4 has been independently lost up to seven times in the fungal lineage. In addition to the trend of loss in fungi, we demonstrate that the duplication that gave rise to the β subunits of the AP-1 and AP-2 complexes in S. cerevisiae occurred before the divergence of F. alba and Fungi. Finally, our investigation into the AP complement of basal fungi (Microsporidia and Cryptomycota) demonstrates that while the cryptomycete Rozella allomyces contains an adaptin complement similar to other fungi, the extremely reduced Microsporidia retain, at most, a single cryptic AP complex in the absence of clathrin or any other putative AP-associated coat protein.
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Affiliation(s)
- Lael D Barlow
- Department of Cell Biology; Faculty of Medicine and Dentistry; University of Alberta; Edmonton, Alberta, Canada
| | - Joel B Dacks
- Department of Cell Biology; Faculty of Medicine and Dentistry; University of Alberta; Edmonton, Alberta, Canada
| | - Jeremy G Wideman
- Department of Cell Biology; Faculty of Medicine and Dentistry; University of Alberta; Edmonton, Alberta, Canada
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