DOCSLIB.ORG

Membrane Transport: Tethers and Trapps Martin Lowe

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Membrane Transport: Tethers and Trapps Martin Lowe View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Elsevier - Publisher Connector Dispatch R407 Membrane transport: Tethers and TRAPPs Martin Lowe Transport vesicles are tethered to their target TRAPP was identified using a combination of yeast genet- membrane prior to the interaction of v-SNAREs and ics and protein biochemistry. The TRAPP subunit Bet3p t-SNAREs across the membrane junction. Recent was first identified by virtue of its genetic interactions with evidence suggests tethering is a complex process the ER-to-Golgi t-SNARE Bet1p [3]. Epitope tagging of requiring multiple components. Bet3p and purification of the tagged protein from yeast lysates resulted in the isolation of the TRAPP complex [4]. Address: School of Biological Sciences, University of Manchester, 2.205 Stopford Building, Oxford Road, Manchester M13 9PT, UK. TRAPP is highly conserved in evolution, with yeast sub- E-mail: [email protected] units sharing between 29 and 54% identity at the amino- acid level with their human counterparts [4,5]. There is no Current Biology 2000, 10:R407–R409 sequence homology with other known proteins. Genetic 0960-9822/00/$ – see front matter interactions between the TRAPP subunits Bet3p and © 2000 Elsevier Science Ltd. All rights reserved. Bet5p with several ER-to-Golgi SNAREs, Uso1p (a Golgi tethering factor), and Yprt1p (a member of the Rab family Transport along the secretory and endocytic pathways in of small GTPases with a demonstrated role in vesicle eukaryotic cells is mediated by vesicular carriers, which docking), strongly suggested that TRAPP was involved in bud from one compartment and fuse with the next com- a late stage in ER-to-Golgi transport [3,6]. This was con- partment in the pathway. Vesicle targeting and fusion firmed by in vitro experiments which showed that TRAPP must be tightly controlled to ensure an ordered flow acts after vesicle budding from the ER but before fusion through the pathway and prevent inappropriate mixing of with the Golgi complex [4]. compartments. Vesicle docking was originally thought to be mediated by ‘SNAREs’ — integral membrane pro- TRAPP has been localised by subcellular fractionation and teins found predominantly on vesicle (v-SNARE) or light microscopy to the Golgi complex in yeast, and unlike target (t-SNARE) membranes [1]. The ability of the ER-to-Golgi SNAREs, it appears not to cycle constitu- SNAREs to form specific v-SNARE–t-SNARE pairs tively through the ER [2]. Furthermore, although TRAPP made them attractive candidates for mediating docking. is a peripheral membrane protein complex, it is tightly asso- However, the finding that some SNAREs can function at ciated with Golgi membranes and is even resistant to more than one step in vivo, the ability of some SNAREs extraction with the non-ionic detergent Triton X-100 [5]. to interact promiscuously in vitro, and the localisation of These findings are consistent with the idea that TRAPP SNAREs to more than one compartment suggested that might determine the site of delivery of ER-derived trans- SNAREs cannot be the sole determinants of docking port vesicles. A role for TRAPP in vesicle tethering was specificity. This made it likely that other components subsequently demonstrated using an in vitro transport assay would impart specificity, and the identification of tether- designed to distinguish between the attachment and fusion ing factors such as the TRAPP complex recently of ER-derived vesicles with Golgi membranes [2]. Inhibi- described by Ferro-Novick and colleagues [2] suggests tion of SNARE assembly prevented fusion but not vesicle this is indeed the case. attachment, while depletion of Bet3p prevented both attachment and fusion. These were restored by addition of Tethering is defined as the initial attachment of a Bet3p-containing cytosol, suggesting Bet3p was the missing transport vesicle with its target membrane, an event that component, but formal proof awaits the re-addition of puri- occurs prior to pairing of SNAREs (the acronym stands for fied native TRAPP, which has so far been unavailable. ‘SNAP receptors’, where SNAP is ‘soluble NSF attach- ment protein’ and NSF is the ATPase ‘N-ethylmaleimide- In addition to TRAPP, two other factors are required for sensitive factor’). Tethering factors have now been tethering of ER-derived vesicles to Golgi membranes in identified for a number of different membrane transport yeast: Uso1p and the Sec34p–Sec35p complex (Figure 1). steps, and although they appear diverse in terms of Uso1p is a parallel homodimer with two globular heads primary structure, they share common characteristics in and an extended coiled-coil tail [7]. Unlike TRAPP, being either elongated coiled-coil proteins or multi- Uso1p is largely cytosolic and is recruited onto membranes subunit complexes. The latter category is typified by during transport in a Ypt1p-dependent manner [8]. Uso1p TRAPP (for ‘transport protein particle’), a complex of ten appears to be the major cytosolic tethering factor for ER- subunits which has recently been identified as an essential derived vesicles, as purified Uso1p alone can substitute for factor for tethering of endoplasmic reticulum (ER)-derived total cytosol in an in vitro vesicle tethering assay [8]. While transport vesicles to Golgi membranes [2]. the subunit composition of the approximately 700 kDa R408 Current Biology Vol 10 No 11 Figure 1 Transport vesicle Coiled-coil tethering protein v-SNARE (Uso1p) Sec34p–Sec35p ? Target specifier (TRAPP) Rab-GTP (Ypt1p) Sly1p t-SNARE Target membrane Pre-tethering Tethering SNARE pairing Current Biology A model for vesicle docking using ER-to-Golgi transport in yeast as Sec34p—Sec35p complex would also somehow participate in this an example. The site of vesicle docking would be specified by a tethering event. Tethering of the vesicle would trigger release of the tethering complex restricted to that location (TRAPP). Binding of a inhibitory t-SNARE-binding protein Sly1p, making the t-SNARE GTP-bound Rab protein (Ypt1p) to that site would stimulate competent for binding to a v-SNARE. Reorganisation of the recruitment of an elongated coiled-coil tethering protein (Uso1p). tethering complex would then facilitate v-SNARE—t-SNARE pairing This in turn would facilitate capture of the transport vesicle, forming across the membrane junction, which would lead either directly or a bridge between the vesicle and target membrane. The indirectly to membrane fusion. Sec34p–Sec35p complex is not clear [9,10], it is known to Tethering of post-Golgi secretory vesicles to the plasma peripherally associate with membranes [9–11] and deple- membrane in yeast requires the heptameric ‘Exocyst’ tion of either Sec34p or Sec35p prevents tethering of ER complex, which is reminiscent of TRAPP [16]. The vesicles in the same in vitro tethering assay used to show ‘Exocyst’ subunit Sec3p is restricted to sites of polarised the tethering function of Uso1p [9,11]. Neither Sec34p or secretion, suggesting that it marks plasma membrane Sec35p share any similarity with TRAPP subunits, indi- docking sites for secretory vesicles [17]. Similarly, the cating these are distinct complexes. The three ER-to- mammalian ‘Exocyst’ homologue — the Sec6–Sec8 Golgi tethering factors interact genetically, consistent with complex — is recruited to cell-cell contacts, where it spec- their role being at the same stage in transport, but whether ifies delivery of vesicles to the basolateral membrane of any physical association exists is unclear, as is the underly- epithelial cells [18]. Electron microscopy studies have ing mechanism by which the three factors co-operate in shown that the Sec6–Sec8 complex has a 30 nanometre the tethering reaction. elongated structure, with two arms projecting outwards from one end, suggestive of a linker function [19]. Does tethering of ER-derived vesicles to Golgi mem- Whether the Sec6–Sec8 complex acts in conjunction with branes share common features with tethering events in a coiled-coil protein is not known, but a physical associa- other membrane transport steps? One common feature is tion with septin filaments has been shown [19] suggesting the requirement for a Rab protein, with genetic and/or these two structures may co-operate in vesicle tethering at physical interaction between the tethering factor and a the plasma membrane. Rab protein demonstrated in nearly all cases. Another feature common to most transport steps is the involve- The identification of three different tethering complexes ment of an elongated coiled-coil protein structurally operating at one transport step suggests that tethering is similar to Uso1p [12–15]. These are predominantly cytoso- more complex than a simple cross-bridging of two mem- lic proteins which are recruited onto membranes in a Rab branes. Tethering might rather be thought of as a series of protein-dependent manner. None of the coiled-coil events that leads to pairing of v-SNAREs and t-SNAREs tethers (apart from Uso1p) have so far been shown to act at the target membrane (Figure 1). Important steps might in conjunction with other oligomeric tethering complexes include: first, specification of the vesicle delivery site; (analogous to TRAPP or Sec34p–Sec35p). second, the recruitment of components capable of Dispatch R409 initiating vesicle capture; third, the formation of a bridge 18. Grindstaff KK, Yeaman C, Anandasabapathy N, Hsu SC, Rodriguez-Boulan E, Scheller RH, Nelson WJ: Sec6/8 complex is between the vesicle and target membrane; fourth, a recruited to cell-cell contacts and specifies transport vesicle conformational change to allow the v-SNAREs and delivery to the basal-lateral membrane in epithelial cells. Cell t-SNAREs to come into close enough proximity to inter- 1998, 93:731-740. 19. Hsu SC, Hazuka CD, Roth R, Foletti DL, Heuser J, Scheller RH: act; and fifth, break-up of tethers to prime the tethering Subunit composition, protein interactions, and structures of the proteins for another round of transport. mammalian brain sec6/8 complex and septin filaments.
Load more

Recommended publications
  • Genome-Wide Rnai Screens Identify Genes Required for Ricin and PE Intoxications
    Developmental Cell Article Genome-Wide RNAi Screens Identify Genes Required for Ricin and PE Intoxications Dimitri Moreau,1 Pankaj Kumar,1 Shyi Chyi Wang,1 Alexandre Chaumet,1 Shin Yi Chew,1 He´ le` ne Chevalley,1 and Fre´ de´ ric Bard1,* 1Institute of Molecular and Cell Biology, 61 Biopolis Drive, Proteos, Singapore 138673, Singapore *Correspondence: [email protected] DOI 10.1016/j.devcel.2011.06.014 SUMMARY In the lumen of the ER, these toxins are thought to interact with elements of the ER-associated degradation (ERAD) pathway, Protein toxins such as Ricin and Pseudomonas which targets misfolded proteins in the ER for degradation. exotoxin (PE) pose major public health challenges. This interaction is proposed to allow translocation to the cytosol Both toxins depend on host cell machinery for inter- without resulting in toxin degradation (Johannes and Ro¨ mer, nalization, retrograde trafficking from endosomes 2010). to the ER, and translocation to cytosol. Although Obviously, this complex set of membrane-trafficking and both toxins follow a similar intracellular route, it is membrane-translocation events involves many host proteins, some of which have already been described (Johannes and unknown how much they rely on the same genes. Ro¨ mer, 2010; Sandvig et al., 2010). Altering the function of these Here we conducted two genome-wide RNAi screens host proteins could in theory provide a toxin antidote. identifying genes required for intoxication and Consistently, inhibition of retrograde traffic by drugs such as demonstrating that requirements are strikingly Brefeldin A (Sandvig et al., 1991)(Yoshida et al., 1991) or Golgi- different between PE and Ricin, with only 13% over- cide A (Sa´ enz et al., 2009) and Retro-1 and 2 (Stechmann et al., lap.
    [Show full text]
  • 1 the TRAPP Complex Mediates Secretion Arrest Induced
    bioRxiv preprint doi: https://doi.org/10.1101/528380; this version posted January 23, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-ND 4.0 International license. 1 The TRAPP complex mediates secretion arrest induced by stress granule assembly 2 3 Francesca Zappa1, Cathal Wilson1, Giuseppe Di Tullio1, Michele Santoro1, Piero Pucci2, 4 Maria Monti2, Davide D’Amico1, Sandra Pisonero Vaquero1, Rossella De Cegli1, 5 Alessia Romano1, Moin A. Saleem3, Elena Polishchuk1, Mario Failli1, Laura Giaquinto1, 6 Maria Antonietta De Matteis1, 2 7 1 Telethon Institute of Genetics and Medicine, Pozzuoli (Naples), Italy 8 2 Federico II University, Naples, Italy 9 3 Bristol Renal, Bristol Medical School, University of Bristol, UK 10 11 Correspondence to: [email protected], [email protected] 12 1 bioRxiv preprint doi: https://doi.org/10.1101/528380; this version posted January 23, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-ND 4.0 International license. 13 The TRAnsport Protein Particle (TRAPP) complex controls multiple steps along the 14 secretory, endocytic and autophagic pathways and is thus strategically positioned 15 to mediate the adaptation of membrane trafficking to diverse environmental 16 conditions including acute stress. We identified TRAPP as a key component of a 17 branch of the integrated stress response that impinges on the secretory pathway.
    [Show full text]
  • ER-To-Golgi Trafficking and Its Implication in Neurological Diseases
    cells Review ER-to-Golgi Trafficking and Its Implication in Neurological Diseases 1,2, 1,2 1,2, Bo Wang y, Katherine R. Stanford and Mondira Kundu * 1 Department of Pathology, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA; [email protected] (B.W.); [email protected] (K.R.S.) 2 Department of Cell and Molecular Biology, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA * Correspondence: [email protected]; Tel.: +1-901-595-6048 Present address: School of Life Sciences, Xiamen University, Xiamen 361102, China. y Received: 21 November 2019; Accepted: 7 February 2020; Published: 11 February 2020 Abstract: Membrane and secretory proteins are essential for almost every aspect of cellular function. These proteins are incorporated into ER-derived carriers and transported to the Golgi before being sorted for delivery to their final destination. Although ER-to-Golgi trafficking is highly conserved among eukaryotes, several layers of complexity have been added to meet the increased demands of complex cell types in metazoans. The specialized morphology of neurons and the necessity for precise spatiotemporal control over membrane and secretory protein localization and function make them particularly vulnerable to defects in trafficking. This review summarizes the general mechanisms involved in ER-to-Golgi trafficking and highlights mutations in genes affecting this process, which are associated with neurological diseases in humans. Keywords: COPII trafficking; endoplasmic reticulum; Golgi apparatus; neurological disease 1. Overview Approximately one-third of all proteins encoded by the mammalian genome are exported from the endoplasmic reticulum (ER) and transported to the Golgi apparatus, where they are sorted for delivery to their final destination in membrane compartments or secretory vesicles [1].
    [Show full text]
  • 1 the TRAPP Complex Mediates Secretion Arrest Induced by Stress Granule Assembly Francesca Zappa1, Cathal Wilson1, Giusepp
    bioRxiv preprint doi: https://doi.org/10.1101/528380; this version posted February 5, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-ND 4.0 International license. The TRAPP complex mediates secretion arrest induced by stress granule assembly Francesca Zappa1, Cathal Wilson1, Giuseppe Di Tullio1, Michele Santoro1, Piero Pucci2, Maria Monti2, Davide D’Amico1, Sandra Pisonero Vaquero1, Rossella De Cegli1, Alessia Romano1, Moin A. Saleem3, Elena Polishchuk1, Mario Failli1, Laura Giaquinto1, Maria Antonietta De Matteis1, 2 1 Telethon Institute of Genetics and Medicine, Pozzuoli (Naples), Italy 2 Federico II University, Naples, Italy 3 Bristol Renal, Bristol Medical School, University of Bristol, UK Correspondence to: [email protected], [email protected] 1 bioRxiv preprint doi: https://doi.org/10.1101/528380; this version posted February 5, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-ND 4.0 International license. The TRAnsport-Protein-Particle (TRAPP) complex controls multiple membrane trafficking steps and is thus strategically positioned to mediate cell adaptation to diverse environmental conditions, including acute stress. We have identified TRAPP as a key component of a branch of the integrated stress response that impinges on the early secretory pathway. TRAPP associates with and drives the recruitment of the COPII coat to stress granules (SGs) leading to vesiculation of the Golgi complex and an arrest of ER export.
    [Show full text]
  • Glycosylation and Sorting of Secretory Proteins in the Endoplasmic
    CORE brought to you by Recent Publications is this Series: LEENA KARHINEN Gl Helsingin yliopiston digitaalinen arkisto 23/2004 Ilona Oksanen Specificity in Cyanobacterial Lichen Symbiosis and Bioactive Metabolites (Ethylene and Microcystins) 24/2004 Tapani Koskenkari provided by Outsourcing Process and Its Impacts on Pharmaceutical Production 25/2004 Tiina Kauppila Atmospheric Pressure Photoionization-Mass Spectrometry 26/2004 Mikael Björklund ycosylation and sorting of secretory proteins in the endoplasmic reticulum of the yeast Gelatinase-mediated Migration and Invasion of Cancer Cells 27/2004 Mark Tummers To the Root of the Stem Cell Problem – The Evolutionary Importance of the Epithelial Stem Cell Niche During Tooth Development 28/2004 Tuula Puhakainen Physiological and Molecular Analysis of Plant Cold Acclimation 29/2004 Tuija Mustonen Ectodermal Organ Development: Regulation by Notch and Eda Pathways 30/2004 Leo Rouhiainen Characterisation of Anabaena Cyanobacteria: Repeated Sequences and Genes Involved in Biosynthesis of Microcystins and Anabaenopeptilides 31/2004 Shea Beasley Isolation, Identification and Exploitation of Lactic Acid Bacteria from Human and Animal Microbiota 32/2004 Teijo Yrjönen Extraction and Planar Chromatographic Separation Techniques in the Analysis of Natural Products 33/2004 Päivi Tammela Screening Methods for the Evaluation of Biological Activity in Drug Discovery Glycosylation and Sorting of Secretory Proteins 34/2004 Johanna Furuhjelm Rab8 and R-Ras as Modulators of Cell Shape in the Endoplasmic Reticulum
    [Show full text]
  • Structure and Mechanism of TRAPPIII-Mediated Rab1 Activation
    bioRxiv preprint doi: https://doi.org/10.1101/2020.10.08.332312; this version posted October 8, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. Structure and mechanism of TRAPPIII-mediated Rab1 activation Aaron M.N. Joiner1, Ben P. Phillips2, Kumar Yugandhar3, Ethan J. Sanford1, Marcus B. Smolka1, Haiyuan Yu3, Elizabeth A. Miller2, J. Christopher Fromme1,4 1 Department of Molecular Biology and Genetics/Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY, USA 2 MRC Laboratory of Molecular Biology, Cambridge, United Kingdom 3 Department of Computational Biology/Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY, USA 4 Corresponding author: [email protected] ABSTRACT The GTPase Rab1 is a master regulator of both the early secretory pathWay and autophagy. Rab1 activation is controlled by its GEF (guanine nucleotide exchange factor), the multi-subunit TRAPPIII complex. The Trs85 regulatory subunit is critical for robust activation of Rab1 but its mechanistic role Within the complex has remained unclear. Here We report the cryo-EM structure of the intact yeast TRAPPIII complex bound to its substrate Rab1/Ypt1. The orientation of the Rab1/Ypt1 hypervariable domain When bound to the complex leads to a model for hoW TRAPPIII associates With and activates Rab1/Ypt1 at the membrane surface. We identify a conserved amphipathic a-helix motif within Trs85 and demonstrate that this helix is required for stable membrane binding and Rab1/Ypt1 activation by TRAPPIII.
    [Show full text]
  • 19432.Full.Pdf
    The EM structure of the TRAPPIII complex leads to the identification of a requirement for COPII vesicles on the macroautophagy pathway Dongyan Tana,b,1, Yiying Caic,1, Juan Wangd,e, Jinzhong Zhangd,e, Shekar Menond,e,2, Hui-Ting Choua,b, Susan Ferro-Novickd,e,3, Karin M. Reinischc,3, and Thomas Walza,b,3 aDepartment of Cell Biology, bHoward Hughes Medical Institute, Harvard Medical School, Boston, MA 02115; cDepartment of Cell Biology, Yale University School of Medicine, New Haven, CT 06520; and dDepartment of Cellular and Molecular Medicine, eHoward Hughes Medical Institute, University of California, San Diego, La Jolla, CA 92093 Edited by Axel T. Brunger, Stanford University, Stanford, CA, and approved October 22, 2013 (received for review August 29, 2013) The transport protein particle (TRAPP) III complex, comprising the Atg1 kinase, to the PAS (9). TRAPPIII is one of three multimeric TRAPPI complex and additional subunit Trs85, is an autophagy- GEFs, called TRAPPI, TRAPPII, and TRAPPIII, that activate Ypt1 specific guanine nucleotide exchange factor for the Rab GTPase on different trafficking pathways (10). TRAPPI, an elongated com- Ypt1 that is recruited to the phagophore assembly site when plex ∼18 nm in length (11, 12), binds to ER-derived COPII-coated macroautophagy is induced. We present the single-particle elec- vesicles via an interaction between the TRAPPI subunit Bet3 and the tron microscopy structure of TRAPPIII, which reveals that the dome- coat subunit Sec23 (11, 13). The TRAPPIII complex contains the shaped Trs85 subunit associates primarily with the Trs20 subunit same six subunits present in TRAPPI plus one unique subunit, Trs85, of TRAPPI.
    [Show full text]
  • Identification of Conserved, Centrosome-Targeting ASH Domains in TRAPPII Complex Subunits and TRAPPC8
    Identification of conserved, centrosome-targeting ASH domains in TRAPPII complex subunits and TRAPPC8 Schou, Kenneth Bødtker; Morthorst, Stine Kjær; Christensen, Søren Tvorup; Pedersen, Lotte Bang Published in: Cilia DOI: 10.1186/2046-2530-3-6 Publication date: 2014 Document version Publisher's PDF, also known as Version of record Citation for published version (APA): Schou, K. B., Morthorst, S. K., Christensen, S. T., & Pedersen, L. B. (2014). Identification of conserved, centrosome-targeting ASH domains in TRAPPII complex subunits and TRAPPC8. Cilia, 3(6). https://doi.org/10.1186/2046-2530-3-6 Download date: 24. Sep. 2021 Schou et al. Cilia 2014, 3:6 http://www.ciliajournal.com/content/3/1/6 RESEARCH Open Access Identification of conserved, centrosome-targeting ASH domains in TRAPPII complex subunits and TRAPPC8 Kenneth B Schou1,2, Stine K Morthorst1, Søren T Christensen1 and Lotte B Pedersen1* Abstract Background: Assembly of primary cilia relies on vesicular trafficking towards the cilium base and intraflagellar transport (IFT) between the base and distal tip of the cilium. Recent studies have identified several key regulators of these processes, including Rab GTPases such as Rab8 and Rab11, the Rab8 guanine nucleotide exchange factor Rabin8, and the transport protein particle (TRAPP) components TRAPPC3, -C9, and -C10, which physically interact with each other and function together with Bardet Biedl syndrome (BBS) proteins in ciliary membrane biogenesis. However, despite recent advances, the exact molecular mechanisms by which these proteins interact and target to the basal body to promote ciliogenesis are not fully understood. Results: We surveyed the human proteome for novel ASPM, SPD-2, Hydin (ASH) domain-containing proteins.
    [Show full text]
  • TRAPPC11 and GOSR2 Mutations Associate with Hypoglycosylation of Α-Dystroglycan and Muscular Dystrophy Austin A
    Larson et al. Skeletal Muscle (2018) 8:17 https://doi.org/10.1186/s13395-018-0163-0 CASEREPORT Open Access TRAPPC11 and GOSR2 mutations associate with hypoglycosylation of α-dystroglycan and muscular dystrophy Austin A. Larson1†, Peter R. Baker II1†, Miroslav P. Milev2†, Craig A. Press1, Ronald J. Sokol1, Mary O. Cox3, Jacqueline K. Lekostaj3, Aaron A. Stence3, Aaron D. Bossler3, Jennifer M. Mueller4, Keshika Prematilake2, Thierry Fotsing Tadjo2, Charles A. Williams4, Michael Sacher2,5*† and Steven A. Moore3*† Abstract Background: Transport protein particle (TRAPP) is a supramolecular protein complex that functions in localizing proteins to the Golgi compartment. The TRAPPC11 subunit has been implicated in muscle disease by virtue of homozygous and compound heterozygous deleterious mutations being identified in individuals with limb girdle muscular dystrophy and congenital muscular dystrophy. It remains unclear how this protein leads to muscle disease. Furthermore, a role for this protein, or any other membrane trafficking protein, in the etiology of the dystroglycanopathy group of muscular dystrophies has yet to be found. Here, using a multidisciplinary approach including genetics, immunofluorescence, western blotting, and live cell analysis, we implicate both TRAPPC11 and another membrane trafficking protein, GOSR2, in α-dystroglycan hypoglycosylation. Case presentation: Subject 1 presented with severe epileptic episodes and subsequent developmental deterioration. Upon clinical evaluation she was found to have brain, eye, and liver abnormalities. Her serum aminotransferases and creatine kinase were abnormally high. Subjects 2 and 3 are siblings from a family unrelated to subject 1. Both siblings displayed hypotonia, muscle weakness, low muscle bulk, and elevated creatine kinase levels. Subject 3 also developed a seizure disorder.
    [Show full text]
  • Recognition and Tethering of Transport Vesicles at the Golgi Apparatus
    The University of Manchester Research Recognition and tethering of transport vesicles at the Golgi apparatus DOI: 10.1016/j.ceb.2017.02.003 Document Version Accepted author manuscript Link to publication record in Manchester Research Explorer Citation for published version (APA): Witkos, T., & Lowe, M. (2017). Recognition and tethering of transport vesicles at the Golgi apparatus. Current opinion in cell biology, 47, 16-23. https://doi.org/10.1016/j.ceb.2017.02.003 Published in: Current opinion in cell biology Citing this paper Please note that where the full-text provided on Manchester Research Explorer is the Author Accepted Manuscript or Proof version this may differ from the final Published version. If citing, it is advised that you check and use the publisher's definitive version. General rights Copyright and moral rights for the publications made accessible in the Research Explorer are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. Takedown policy If you believe that this document breaches copyright please refer to the University of Manchester’s Takedown Procedures [http://man.ac.uk/04Y6Bo] or contact [email protected] providing relevant details, so we can investigate your claim. Download date:25. Sep. 2021 Recognition and tethering of transport vesicles at the Golgi apparatus Tomasz M. Witkos and Martin Lowe Faculty of Biology, Medicine and Health, University of Manchester, Michael Smith Building, Oxford Road, Manchester, M13 9PT, UK Email: [email protected] Short title: Vesicle recognition and tethering at the Golgi apparatus Word count: 3,831 (excluding references and figure legends) 1 Abstract The Golgi apparatus occupies a central position within the secretory pathway where it is a hub for vesicle trafficking.
    [Show full text]
  • (HOPS) Tethering Complex
    Molecular architecture of the multisubunit homotypic fusion and vacuole protein sorting (HOPS) tethering complex Cornelia Bröckera,1, Anne Kuhleeb,1, Christos Gatsogiannisb,1, Henning J. kleine Balderhaara, Carina Hönschera, Siegfried Engelbrecht-Vandréa, Christian Ungermanna,2, and Stefan Raunserb,2 aBiochemistry Section, Department of Biology, University of Osnabrück, 49076 Osnabrück, Germany; and bDepartment of Physical Biochemistry, Max Planck Institute of Molecular Physiology, 44227 Dortmund, Germany Edited* by William T. Wickner, Dartmouth Medical School, Hanover, NH, and approved December 22, 2011 (received for review October 28, 2011) Membrane fusion within the eukaryotic endomembrane system binds the Rab7 GTPase Ypt7 via its subunits Vps41 and Vps39 depends on the initial recognition of Rab GTPase on transport vesicles (15, 16) and promotes fusion of late endosomes, AP-3 vesicles, by multisubunit tethering complexes and subsequent coupling to and autophagosomes with vacuoles, as well as homotypic fusion SNARE-mediated fusion. The conserved vacuolar/lysosomal homo- (2, 17). All HOPS and CORVET subunits—except Vps33—likely typic fusion and vacuole protein sorting (HOPS) tethering complex consist of an N-terminal β-propeller and a C-terminal α-solenoid combines both activities. Here we present the overall structure of region (13, 16). They thus differ structurally from the CATCHR the fusion-active HOPS complex. Our data reveal a flexible ≈30-nm (complex associated with tethering containing helical rods) elongated seahorse-like structure, which can adopt contracted and complexes such as Dsl1, COG, GARP, and exocyst (1). HOPS is elongated shapes. Surprisingly, both ends of the HOPS complex con- also the only complex for which an in vitro fusion assay has been tain a Rab-binding subunit: Vps41 and Vps39.
    [Show full text]
  • Characterization of Three TRAPPC11 Variants Suggests a Critical Role For
    www.nature.com/scientificreports There are amendments to this paper OPEN Characterization of three TRAPPC11 variants suggests a critical role for the extreme carboxy Received: 10 April 2019 Accepted: 11 September 2019 terminus of the protein Published: 1 October 2019 Miroslav P. Milev1, Daniela Stanga1, Anne Schänzer2, Andrés Nascimento3,4, Djenann Saint-Dic1, Carlos Ortez3, Daniel Natera-de Benito3, Desiré González Barrios5, Jaume Colomer3, Carmen Badosa3, Cristina Jou4,6, Pia Gallano4,7, Lidia Gonzalez-Quereda4,7, Ana Töpf8, Katherine Johnson8,9, Volker Straub8, Andreas Hahn10, Michael Sacher1,11 & Cecilia Jimenez-Mallebrera3,4 TRAPPC11 was identifed as a component of the TRAPP III complex that functions in membrane trafcking and autophagy. Variants in TRAPPC11 have been reported to be associated with a broad spectrum of phenotypes but all afected individuals display muscular pathology. Identifying additional variants will further our understanding of the clinical spectrum of phenotypes and will reveal regions of the protein critical for its functions. Here we report three individuals from unrelated families that have bi-allellic TRAPPC11 variants. Subject 1 harbors a compound heterozygous variant (c.1287 + 5G > A and c.3379_3380insT). The former variant results in a partial deletion of the foie gras domain (p.Ala372_ Ser429del), while the latter variant results in a frame-shift and extension at the carboxy terminus (p.Asp1127Valfs*47). Subjects 2 and 3 both harbour a homozygous missense variant (c.2938G > A; p.Gly980Arg). Fibroblasts from all three subjects displayed membrane trafcking defects manifested as delayed endoplasmic reticulum (ER)-to-Golgi transport and/or a delay in protein exit from the Golgi.
    [Show full text]