1
|
Wisner SR, Chlebowski M, Mandal A, Mai D, Stein C, Petralia RS, Wang YX, Drerup CM. An initial HOPS-mediated fusion event is critical for autophagosome transport initiation from the axon terminal. Autophagy 2024:1-22. [PMID: 38899385 DOI: 10.1080/15548627.2024.2366122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2023] [Accepted: 06/05/2024] [Indexed: 06/21/2024] Open
Abstract
In neurons, macroautophagy/autophagy is a frequent and critical process. In the axon, autophagy begins in the axon terminal, where most nascent autophagosomes form. After formation, autophagosomes must initiate transport to exit the axon terminal and move toward the cell body via retrograde transport. During retrograde transport these autophagosomes mature through repetitive fusion events. Complete lysosomal cargo degradation occurs largely in the cell body. The precipitating events to stimulate retrograde autophagosome transport have been debated but their importance is clear: disrupting neuronal autophagy or autophagosome transport is detrimental to neuronal health and function. We have identified the HOPS complex as essential for early autophagosome maturation and consequent initiation of retrograde transport from the axon terminal. In yeast and mammalian cells, HOPS controls fusion between autophagosomes and late endosomes with lysosomes. Using zebrafish strains with loss-of-function mutations in vps18 and vps41, core components of the HOPS complex, we found that disruption of HOPS eliminates autophagosome maturation and disrupts retrograde autophagosome transport initiation from the axon terminal. We confirmed this phenotype was due to loss of HOPS complex formation using an endogenous deletion of the HOPS binding domain in Vps18. Finally, using pharmacological inhibition of lysosomal proteases, we show that initiation of autophagosome retrograde transport requires autophagosome maturation. Together, our data demonstrate that HOPS-mediated fusion events are critical for retrograde autophagosome transport initiation through promoting autophagosome maturation. This reveals critical roles for the HOPS complex in neuronal autophagy which deepens our understanding of the cellular pathology of HOPS-complex linked neurodegenerative diseases.Abbreviations: CORVET: Class C core vacuole/endosome tethering; gRNA: guide RNA; HOPS: homotypic fusion and protein sorting; pLL: posterior lateral line; Vps18: VPS18 core subunit of CORVET and HOPS complexes; Vps41: VPS41 subunit of HOPS complex.
Collapse
Affiliation(s)
- Serena R Wisner
- Department of Integrative Biology, University of Wisconsin-Madison, Madison, WI, USA
- Neuroscience Training Program, University of Wisconsin-Madison, Madison, WI, USA
| | - Madison Chlebowski
- Department of Integrative Biology, University of Wisconsin-Madison, Madison, WI, USA
| | - Amrita Mandal
- National Institute of Child Health and Human Development, NIH, Bethesda, MD, USA
| | - Don Mai
- Department of Integrative Biology, University of Wisconsin-Madison, Madison, WI, USA
| | - Chris Stein
- Department of Integrative Biology, University of Wisconsin-Madison, Madison, WI, USA
| | - Ronald S Petralia
- Advanced Imaging Core, National Institute of Deafness and Other Communication Disorders, NIH, Bethesda, MD, USA
| | - Ya-Xian Wang
- Advanced Imaging Core, National Institute of Deafness and Other Communication Disorders, NIH, Bethesda, MD, USA
| | - Catherine M Drerup
- Department of Integrative Biology, University of Wisconsin-Madison, Madison, WI, USA
- Neuroscience Training Program, University of Wisconsin-Madison, Madison, WI, USA
| |
Collapse
|
2
|
Liu JJ, Xu ZM, Liu Y, Guo XY, Zhang WB. A novel lysosome-related prognostic signature associated with prognosis and immune infiltration landscape in oral squamous cell carcinoma. Heliyon 2024; 10:e26100. [PMID: 38420448 PMCID: PMC10900434 DOI: 10.1016/j.heliyon.2024.e26100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2023] [Revised: 02/07/2024] [Accepted: 02/07/2024] [Indexed: 03/02/2024] Open
Abstract
Background Predicting the outcome of oral squamous cell carcinoma (OSCC) is challenging due to its diverse nature and intricate causes. This research explores how lysosome-associated genes (LRGs) might forecast overall survival (OS) and correlate with immune infiltration in OSCC patients. Methods We analyzed OSCC patients' LRGs' mRNA expression data and clinical details from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO). Through univariate Cox regression, we pinpointed LRGs with prognostic potential. A signature comprising 12 LRGs linked to prognosis was developed via the Least Absolute Shrinkage and Selection Operator (LASSO) in a training dataset. Patients were classified as higher or lower risk based on their risk scores, and the prognostic independence of the risk score was assessed using multivariate analysis. The model's robustness and precision were confirmed through bioinformatics in the GEO test set. Differential gene expression analysis between risk groups highlighted functional disparities, while various immune evaluation methods elucidated immune differences. Results The prognostic framework utilized 12 LRGs (SLC46A3, MANBA, NEU1, SDCBP, BRI3, TMEM175, CD164, GPC1, SFTPB, TPP1, Biglycan (BGN) and TMEM192), showing that higher risk was associated with poorer OS. This set of genes independently predicted OS in OSCC, linking LRGs to cellular adhesion and extracellular matrix involvement. Initial assessments using ssGSEA and CIBERSORT suggested that the adverse outcomes in the higher-risk cohort may be tied to immune system deregulation. Conclusion Twelve-LRGs signature has been identified for OSCC prognosis prediction, offering novel directions for lysosome-targeted therapies against OSCC.
Collapse
Affiliation(s)
- Jing-Jing Liu
- Department of Stomatology, The Fourth Affiliated Hospital of Soochow University, Suzhou Dushu Lake Hospital, Suzhou, 215125, China
| | - Zhi-Ming Xu
- Department of Stomatology, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou Municipal Hospital, Gusu School, Nanjing Medical University, Suzhou, 215008, China
| | - Ying Liu
- Department of Stomatology, The Fourth Affiliated Hospital of Soochow University, Suzhou Dushu Lake Hospital, Suzhou, 215125, China
| | - Xi-Yuan Guo
- Department of Stomatology, The Fourth Affiliated Hospital of Soochow University, Suzhou Dushu Lake Hospital, Suzhou, 215125, China
| | - Wei-Bing Zhang
- Department of Stomatology, The Fourth Affiliated Hospital of Soochow University, Suzhou Dushu Lake Hospital, Suzhou, 215125, China
| |
Collapse
|
3
|
Diao J, Yip CK, Zhong Q. Molecular structures and function of the autophagosome-lysosome fusion machinery. AUTOPHAGY REPORTS 2024; 3:2305594. [PMID: 38344192 PMCID: PMC10852212 DOI: 10.1080/27694127.2024.2305594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 01/09/2024] [Indexed: 02/15/2024]
Abstract
Macroautophagy (also known as autophagy) plays a pivotal role in maintaining cellular homeostasis. The terminal step of the multi-step autophagy degradation pathway involves fusion between the cargo-laden, double-membraned autophagosome and the lytic organelle lysosome/vacuole. Over the past decade, various core components of the molecular machinery that execute this critical terminal autophagy event have been identified. This review highlights recent advances in understanding the molecular structures, biochemical functions, and regulatory mechanisms of key components of this highly sophisticated machinery including the SNARE fusogens, tethering factors, Rab GTPases and associated guanine nucleotide exchange factors, and other accessory factors.
Collapse
Affiliation(s)
- Jiajie Diao
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, Ohio, U.S.A
| | - Calvin K. Yip
- Life Sciences Institute, Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Qing Zhong
- Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Department of Pathophysiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| |
Collapse
|
4
|
Kümmel D, Herrmann E, Langemeyer L, Ungermann C. Molecular insights into endolysosomal microcompartment formation and maintenance. Biol Chem 2022; 404:441-454. [PMID: 36503831 DOI: 10.1515/hsz-2022-0294] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 11/22/2022] [Indexed: 12/14/2022]
Abstract
Abstract
The endolysosomal system of eukaryotic cells has a key role in the homeostasis of the plasma membrane, in signaling and nutrient uptake, and is abused by viruses and pathogens for entry. Endocytosis of plasma membrane proteins results in vesicles, which fuse with the early endosome. If destined for lysosomal degradation, these proteins are packaged into intraluminal vesicles, converting an early endosome to a late endosome, which finally fuses with the lysosome. Each of these organelles has a unique membrane surface composition, which can form segmented membrane microcompartments by membrane contact sites or fission proteins. Furthermore, these organelles are in continuous exchange due to fission and fusion events. The underlying machinery, which maintains organelle identity along the pathway, is regulated by signaling processes. Here, we will focus on the Rab5 and Rab7 GTPases of early and late endosomes. As molecular switches, Rabs depend on activating guanine nucleotide exchange factors (GEFs). Over the last years, we characterized the Rab7 GEF, the Mon1-Ccz1 (MC1) complex, and key Rab7 effectors, the HOPS complex and retromer. Structural and functional analyses of these complexes lead to a molecular understanding of their function in the context of organelle biogenesis.
Collapse
Affiliation(s)
- Daniel Kümmel
- Institute of Biochemistry, University of Münster , Corrensstraße 36 , D-48149 Münster , Germany
| | - Eric Herrmann
- Institute of Biochemistry, University of Münster , Corrensstraße 36 , D-48149 Münster , Germany
| | - Lars Langemeyer
- Department of Biology/Chemistry, Biochemistry section , Osnabrück University , Barbarastraße 13 , D-49076 Osnabrück , Germany
- Center of Cellular Nanoanalytics (CellNanOs) , Osnabrück University , Barbarastraße 11 , D-49076 Osnabrück , Germany
| | - Christian Ungermann
- Department of Biology/Chemistry, Biochemistry section , Osnabrück University , Barbarastraße 13 , D-49076 Osnabrück , Germany
- Center of Cellular Nanoanalytics (CellNanOs) , Osnabrück University , Barbarastraße 11 , D-49076 Osnabrück , Germany
| |
Collapse
|
5
|
Monfrini E, Cogiamanian F, Salani S, Straniero L, Fagiolari G, Garbellini M, Carsana E, Borellini L, Biella F, Moggio M, Bresolin N, Corti S, Duga S, Comi GP, Aureli M, Di Fonzo A. A Novel Homozygous VPS11 Variant May Cause Generalized Dystonia. Ann Neurol 2021; 89:834-839. [PMID: 33452836 PMCID: PMC8048445 DOI: 10.1002/ana.26021] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 01/11/2021] [Accepted: 01/13/2021] [Indexed: 01/17/2023]
Abstract
In this work, we describe the association of a novel homozygous VPS11 variant with adult-onset generalized dystonia, providing a detailed clinical report and biological evidence of disease mechanism. Vps11 is a subunit of the homotypic fusion and protein sorting (HOPS) complex, which promotes the fusion of late endosomes and autophagosomes with the lysosome. Functional studies on mutated fibroblasts showed marked lysosomal and autophagic abnormalities, which improved after overexpression of the wild type Vps11 protein. In conclusion, a deleterious VPS11 variant, damaging the autophagic and lysosomal pathways, is the probable genetic cause of a novel form of generalized dystonia. ANN NEUROL 2021;89:834-839.
Collapse
Affiliation(s)
- Edoardo Monfrini
- Foundation IRCCS Ca' Granda Ospedale Maggiore Policlinico, Neurology Unit, Milan, Italy.,Dino Ferrari Center, Neuroscience Section, Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
| | - Filippo Cogiamanian
- Foundation IRCCS Ca' Granda Ospedale Maggiore Policlinico, Department of Neuropathophysiology, University of Milan, Milan, Italy
| | - Sabrina Salani
- Foundation IRCCS Ca' Granda Ospedale Maggiore Policlinico, Neurology Unit, Milan, Italy.,Dino Ferrari Center, Neuroscience Section, Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
| | - Letizia Straniero
- Department of Biomedical Sciences, Humanitas University, Milan, Italy
| | - Gigliola Fagiolari
- Foundation IRCCS Ca' Granda Ospedale Maggiore Policlinico, Neuromuscular and Rare Diseases Unit, Milan, Italy.,Foundation IRCCS Ca' Granda Ospedale Maggiore Policlinico, Healthcare Professionals Department, Milan, Italy
| | - Manuela Garbellini
- Dino Ferrari Center, Neuroscience Section, Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy.,Foundation IRCCS Ca' Granda Ospedale Maggiore Policlinico, Healthcare Professionals Department, Milan, Italy
| | - Emma Carsana
- Dip. Biotecnologie Mediche e Medicina Traslazionale, Università degli Studi di Milano, LITA, Via Fratelli Cervi 93, Segrate, Milan, Italy
| | - Linda Borellini
- Foundation IRCCS Ca' Granda Ospedale Maggiore Policlinico, Department of Neuropathophysiology, University of Milan, Milan, Italy
| | - Fabio Biella
- Foundation IRCCS Ca' Granda Ospedale Maggiore Policlinico, Neurology Unit, Milan, Italy.,Dino Ferrari Center, Neuroscience Section, Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
| | - Maurizio Moggio
- Foundation IRCCS Ca' Granda Ospedale Maggiore Policlinico, Neuromuscular and Rare Diseases Unit, Milan, Italy
| | - Nereo Bresolin
- Foundation IRCCS Ca' Granda Ospedale Maggiore Policlinico, Neurology Unit, Milan, Italy.,Dino Ferrari Center, Neuroscience Section, Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
| | - Stefania Corti
- Foundation IRCCS Ca' Granda Ospedale Maggiore Policlinico, Neurology Unit, Milan, Italy.,Dino Ferrari Center, Neuroscience Section, Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
| | - Stefano Duga
- Department of Biomedical Sciences, Humanitas University, Milan, Italy.,Humanitas Clinical and Research Center, IRCCS, Milan, Italy
| | - Giacomo P Comi
- Foundation IRCCS Ca' Granda Ospedale Maggiore Policlinico, Neurology Unit, Milan, Italy.,Foundation IRCCS Ca' Granda Ospedale Maggiore Policlinico, Neuromuscular and Rare Diseases Unit, Milan, Italy
| | - Massimo Aureli
- Dip. Biotecnologie Mediche e Medicina Traslazionale, Università degli Studi di Milano, LITA, Via Fratelli Cervi 93, Segrate, Milan, Italy
| | - Alessio Di Fonzo
- Foundation IRCCS Ca' Granda Ospedale Maggiore Policlinico, Neurology Unit, Milan, Italy.,Dino Ferrari Center, Neuroscience Section, Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
| |
Collapse
|
6
|
Vasilev F, Sukhomyasova A, Otomo T. Mucopolysaccharidosis-Plus Syndrome. Int J Mol Sci 2020; 21:ijms21020421. [PMID: 31936524 PMCID: PMC7013929 DOI: 10.3390/ijms21020421] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Accepted: 01/07/2020] [Indexed: 12/18/2022] Open
Abstract
Previously, we reported a novel disease of impaired glycosaminoglycans (GAGs) metabolism without deficiency of known lysosomal enzymes—mucopolysaccharidosis-plus syndrome (MPSPS). MPSPS, whose pathophysiology is not elucidated, is an autosomal recessive multisystem disorder caused by a specific mutation p.R498W in the VPS33A gene. VPS33A functions in endocytic and autophagic pathways, but p.R498W mutation did not affect both of these pathways in the patient’s skin fibroblast. Nineteen patients with MPSPS have been identified: seventeen patients were found among the Yakut population (Russia) and two patients from Turkey. Clinical features of MPSPS patients are similar to conventional mucopolysaccharidoses (MPS). In addition to typical symptoms for conventional MPS, MPSPS patients developed other features such as congenital heart defects, renal and hematopoietic disorders. Diagnosis generally requires evidence of clinical picture similar to MPS and molecular genetic testing. Disease is very severe, prognosis is unfavorable and most of patients died at age of 10–20 months. Currently there is no specific therapy for this disease and clinical management is limited to supportive and symptomatic treatment.
Collapse
Affiliation(s)
- Filipp Vasilev
- Department of Molecular and Genetic Medicine, Kawasaki Medical School, Kurashiki, Okayama 701-0192, Japan;
- International Research Fellow of Japan Society for the Promotion of Science (Postdoctoral Fellowships for Research in Japan (Standard)), Tokyo 102-0083, Japan
- Laboratory of Genome Medicine, North-Eastern Federal University, 677013 Yakutsk, Sakha Republic, Russia;
| | - Aitalina Sukhomyasova
- Laboratory of Genome Medicine, North-Eastern Federal University, 677013 Yakutsk, Sakha Republic, Russia;
| | - Takanobu Otomo
- Department of Molecular and Genetic Medicine, Kawasaki Medical School, Kurashiki, Okayama 701-0192, Japan;
- Correspondence: ; Tel.: +81-86-462-1111
| |
Collapse
|
7
|
Ungermann C, Kümmel D. Structure of membrane tethers and their role in fusion. Traffic 2019; 20:479-490. [DOI: 10.1111/tra.12655] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 04/26/2019] [Accepted: 05/03/2019] [Indexed: 12/27/2022]
Affiliation(s)
- Christian Ungermann
- Biochemistry Section, Department of Biology/ChemistryUniversity of Osnabrück Osnabrück Germany
- Center for Cellular Nanoanalytics (CellNanOs)University of Osnabrück Osnabrück Germany
| | - Daniel Kümmel
- Biochemistry & Structural Biology Section, Institute of BiochemistryUniversity of Münster Münster Germany
| |
Collapse
|
8
|
Vps11 and Vps18 of Vps-C membrane traffic complexes are E3 ubiquitin ligases and fine-tune signalling. Nat Commun 2019; 10:1833. [PMID: 31015428 PMCID: PMC6478910 DOI: 10.1038/s41467-019-09800-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 04/02/2019] [Indexed: 12/11/2022] Open
Abstract
In response to extracellular signals, many signalling proteins associated with the plasma membrane are sorted into endosomes. This involves endosomal fusion, which depends on the complexes HOPS and CORVET. Whether and how their subunits themselves modulate signal transduction is unknown. We show that Vps11 and Vps18 (Vps11/18), two common subunits of the HOPS/CORVET complexes, are E3 ubiquitin ligases. Upon overexpression of Vps11/Vps18, we find perturbations of ubiquitination in signal transduction pathways. We specifically demonstrate that Vps11/18 regulate several signalling factors and pathways, including Wnt, estrogen receptor α (ERα), and NFκB. For ERα, we demonstrate that the Vps11/18-mediated ubiquitination of the scaffold protein PELP1 impairs the activation of ERα by c-Src. Thus, proteins involved in membrane traffic, in addition to performing their well-described role in endosomal fusion, fine-tune signalling in several different ways, including through ubiquitination.
Collapse
|
9
|
VPS18 recruits VPS41 to the human HOPS complex via a RING-RING interaction. Biochem J 2017; 474:3615-3626. [PMID: 28931724 PMCID: PMC5651818 DOI: 10.1042/bcj20170588] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Revised: 09/13/2017] [Accepted: 09/15/2017] [Indexed: 02/06/2023]
Abstract
Eukaryotic cells use conserved multisubunit membrane tethering complexes, including CORVET (class C core vacuole/endosome tethering) and HOPS (homotypic fusion and vacuole protein sorting), to control the fusion of endomembranes. These complexes have been extensively studied in yeast, but to date there have been far fewer studies of metazoan CORVET and HOPS. Both of these complexes comprise six subunits: a common four-subunit core and two unique subunits. Once assembled, these complexes function to recognise specific endosomal membrane markers and facilitate SNARE-mediated membrane fusion. CORVET promotes the homotypic fusion of early endosomes, while HOPS promotes the fusion of lysosomes to late endosomes and autophagosomes. Many of the subunits of both CORVET and HOPS contain putative C-terminal zinc-finger domains. Here, the contribution of these domains to the assembly of the human CORVET and HOPS complexes has been examined. Using biochemical techniques, we demonstrate that the zinc-containing RING (really interesting new gene) domains of human VPS18 and VPS41 interact directly to form a stable heterodimer. In cells, these RING domains are able to integrate into endogenous HOPS, showing that the VPS18 RING domain is required to recruit VPS41 to the core complex subunits. Importantly, this mechanism is not conserved throughout eukaryotes, as yeast Vps41 does not contain a C-terminal zinc-finger motif. The subunit analogous to VPS41 in human CORVET is VPS8, in which the RING domain has an additional C-terminal segment that is predicted to be disordered. Both the RING and disordered C-terminal domains are required for integration of VPS8 into endogenous CORVET complexes, suggesting that HOPS and CORVET recruit VPS41 and VPS8 via distinct molecular interactions.
Collapse
|
10
|
Multiple Roles of the Small GTPase Rab7. Cells 2016; 5:cells5030034. [PMID: 27548222 PMCID: PMC5040976 DOI: 10.3390/cells5030034] [Citation(s) in RCA: 267] [Impact Index Per Article: 33.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Revised: 08/11/2016] [Accepted: 08/12/2016] [Indexed: 12/16/2022] Open
Abstract
Rab7 is a small GTPase that belongs to the Rab family and controls transport to late endocytic compartments such as late endosomes and lysosomes. The mechanism of action of Rab7 in the late endocytic pathway has been extensively studied. Rab7 is fundamental for lysosomal biogenesis, positioning and functions, and for trafficking and degradation of several signaling receptors, thus also having implications on signal transduction. Several Rab7 interacting proteins have being identified leading to the discovery of a number of different important functions, beside its established role in endocytosis. Furthermore, Rab7 has specific functions in neurons. This review highlights and discusses the role and the importance of Rab7 on different cellular pathways and processes.
Collapse
|
11
|
Schroeter S, Beckmann S, Schmitt HD. Coat/Tether Interactions-Exception or Rule? Front Cell Dev Biol 2016; 4:44. [PMID: 27243008 PMCID: PMC4868844 DOI: 10.3389/fcell.2016.00044] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Accepted: 04/25/2016] [Indexed: 12/02/2022] Open
Abstract
Coat complexes are important for cargo selection and vesicle formation. Recent evidence suggests that they may also be involved in vesicle targeting. Tethering factors, which form an initial bridge between vesicles and the target membrane, may bind to coat complexes. In this review, we ask whether these coat/tether interactions share some common mechanisms, or whether they are special adaptations to the needs of very specific transport steps. We compare recent findings in two multisubunit tethering complexes, the Dsl1 complex and the HOPS complex, and put them into context with the TRAPP I complex as a prominent example for coat/tether interactions. We explore where coat/tether interactions are found, compare their function and structure, and comment on a possible evolution from a common ancestor of coats and tethers.
Collapse
Affiliation(s)
- Saskia Schroeter
- Neurobiology, Max Planck Institute for Biophysical Chemistry Göttingen, Germany
| | - Sabrina Beckmann
- Neurobiology, Max Planck Institute for Biophysical Chemistry Göttingen, Germany
| | - Hans Dieter Schmitt
- Neurobiology, Max Planck Institute for Biophysical Chemistry Göttingen, Germany
| |
Collapse
|
12
|
Edvardson S, Gerhard F, Jalas C, Lachmann J, Golan D, Saada A, Shaag A, Ungermann C, Elpeleg O. Hypomyelination and developmental delay associated with VPS11 mutation in Ashkenazi-Jewish patients. J Med Genet 2015; 52:749-53. [PMID: 26307567 DOI: 10.1136/jmedgenet-2015-103239] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2015] [Accepted: 08/03/2015] [Indexed: 12/16/2022]
Abstract
BACKGROUND The genetic heterogeneity of developmental delay and cognitive impairment is vast. The endocytic network is essential for neural development and synaptic plasticity by regulating the sorting of numerous transmembrane proteins. Disruption of the pathway can lead to neuronal pathology. Endosomal biogenesis relies on two Rab proteins, Rab5 and Rab7, which bind to two hexameric tethering complexes, the endosomal class C core vacuole/endosome tethering complex (CORVET) and the late endosomal/lysosomal homotypic fusion and protein sorting complex (HOPS). Both complexes consist of four core proteins and differ by their specific Rab-binding proteins. OBJECTIVES To identify the molecular basis of a neurological disease, which consists of global developmental stagnation at 3-8 months, increasing appendicular spasticity, truncal hypotonia and acquired microcephaly, with variable seizure disorder, accompanied by thin corpus callosum, paucity of white matter and delayed myelination in eight patients from four unrelated Ashkenazi-Jewish (AJ) families. METHODS Exome analysis, homozygosity mapping and Mup1-GFP transport assay in mutant yeast. RESULTS Homozygosity for a missense mutation, p.Cys846Gly, in one of the endosomal biogenesis core proteins, VPS11, was identified in all the patients. This was shown to be a founder mutation with a carrier frequency of 0.6% in the AJ population. The homologous yeast mutant had moderate impairment of fusion of the late endosome to the vacuole in Mup1-GFP transport assay. CONCLUSIONS We speculate that in neuronal cells, impairment of fusion of the late endosome to the vacuole would attenuate the degradation of plasma membrane receptors, thereby underlying the progressive neuronal phenotype in our patients. The VPS11 p.Cys846Gly mutation should be added to the AJ carrier screening panel.
Collapse
Affiliation(s)
- Shimon Edvardson
- Monique and Jacques Roboh Department of Genetic Research, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Frank Gerhard
- Department of Biology/Chemistry, Biochemistry Section, University of Osnabrück, Osnabrück, Germany
| | - Chaim Jalas
- Bonei Olam, Center for Rare Jewish Genetic Disorders, Brooklyn, New York, USA
| | - Jens Lachmann
- Department of Biology/Chemistry, Biochemistry Section, University of Osnabrück, Osnabrück, Germany
| | - Dafna Golan
- Maccabi Health Services, Child Development Center, Jerusalem, Israel
| | - Ann Saada
- Monique and Jacques Roboh Department of Genetic Research, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Avraham Shaag
- Monique and Jacques Roboh Department of Genetic Research, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Christian Ungermann
- Department of Biology/Chemistry, Biochemistry Section, University of Osnabrück, Osnabrück, Germany
| | - Orly Elpeleg
- Monique and Jacques Roboh Department of Genetic Research, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| |
Collapse
|
13
|
Kuhlee A, Raunser S, Ungermann C. Functional homologies in vesicle tethering. FEBS Lett 2015; 589:2487-97. [PMID: 26072291 DOI: 10.1016/j.febslet.2015.06.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Revised: 05/30/2015] [Accepted: 06/01/2015] [Indexed: 11/24/2022]
Abstract
The HOPS multisubunit tethering factor (MTC) is a macromolecular protein complex composed of six different subunits. It is one of the key components in the perception and subsequent fusion of multivesicular bodies and vacuoles. Electron microscopy studies indicate structural flexibility of the purified HOPS complex. Inducing higher rigidity into HOPS by biochemically modifying the complex declines the potential to mediate SNARE-driven membrane fusion. Thus, we propose that integral flexibility seems to be not only a feature, but of essential need for the function of HOPS. This review focuses on the general features of membrane tethering and fusion. For this purpose, we compare the structure and mode of action of different tethering factors to highlight their common central features and mechanisms.
Collapse
Affiliation(s)
- Anne Kuhlee
- Department of Structural Biochemistry, Max-Planck Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany.
| | - Stefan Raunser
- Department of Structural Biochemistry, Max-Planck Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany
| | - Christian Ungermann
- Department of Biology, University of Osnabrück, Barbarastrasse 13, 49076 Osnabrück, Germany
| |
Collapse
|