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Almousa H, Lewis SA, Bakhtiari S, Nordlie SH, Pagnozzi A, Magee H, Efthymiou S, Heim JA, Cornejo P, Zaki MS, Anwar N, Maqbool S, Rahman F, Neilson DE, Vemuri A, Jin SC, Yang XR, Heidari A, van Gassen K, Trimouille A, Thauvin-Robinet C, Liu J, Bruel AL, Tomoum H, Shata MO, Hashem MO, Toosi MB, Karimiani EG, Yeşil G, Lingappa L, Baruah D, Ebrahimzadeh F, Van-Gils J, Faivre L, Zamani M, Galehdari H, Sadeghian S, Shariati G, Mohammad R, van der Smagt J, Qari A, Vincent JB, Innes AM, Dursun A, Özgül RK, Akar HT, Bilguvar K, Mignot C, Keren B, Raveli C, Burglen L, Afenjar A, Kaat LD, van Slegtenhorst M, Alkuraya F, Houlden H, Padilla-Lopez S, Maroofian R, Sacher M, Kruer MC. TRAPPC6B biallelic variants cause a neurodevelopmental disorder with TRAPP II and trafficking disruptions. Brain 2024; 147:311-324. [PMID: 37713627 PMCID: PMC10766242 DOI: 10.1093/brain/awad301] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 07/11/2023] [Accepted: 08/10/2023] [Indexed: 09/17/2023] Open
Abstract
Highly conserved transport protein particle (TRAPP) complexes regulate subcellular trafficking pathways. Accurate protein trafficking has been increasingly recognized to be critically important for normal development, particularly in the nervous system. Variants in most TRAPP complex subunits have been found to lead to neurodevelopmental disorders with diverse but overlapping phenotypes. We expand on limited prior reports on TRAPPC6B with detailed clinical and neuroradiologic assessments, and studies on mechanisms of disease, and new types of variants. We describe 29 additional patients from 18 independent families with biallelic variants in TRAPPC6B. We identified seven homozygous nonsense (n = 12 patients) and eight canonical splice-site variants (n = 17 patients). In addition, we identified one patient with compound heterozygous splice-site/missense variants with a milder phenotype and one patient with homozygous missense variants. Patients displayed non-progressive microcephaly, global developmental delay/intellectual disability, epilepsy and absent expressive language. Movement disorders including stereotypies, spasticity and dystonia were also observed. Brain imaging revealed reductions in cortex, cerebellum and corpus callosum size with frequent white matter hyperintensity. Volumetric measurements indicated globally diminished volume rather than specific regional losses. We identified a reduced rate of trafficking into the Golgi apparatus and Golgi fragmentation in patient-derived fibroblasts that was rescued by wild-type TRAPPC6B. Molecular studies revealed a weakened interaction between mutant TRAPPC6B (c.454C>T, p.Q152*) and its TRAPP binding partner TRAPPC3. Patient-derived fibroblasts from the TRAPPC6B (c.454C>T, p.Q152*) variant displayed reduced levels of TRAPPC6B as well as other TRAPP II complex-specific members (TRAPPC9 and TRAPPC10). Interestingly, the levels of the TRAPPC6B homologue TRAPPC6A were found to be elevated. Moreover, co-immunoprecipitation experiments showed that TRAPPC6A co-precipitates equally with TRAPP II and TRAPP III, while TRAPPC6B co-precipitates significantly more with TRAPP II, suggesting enrichment of the protein in the TRAPP II complex. This implies that variants in TRAPPC6B may preferentially affect TRAPP II functions compared to TRAPP III functions. Finally, we assessed phenotypes in a Drosophila TRAPPC6B-deficiency model. Neuronal TRAPPC6B knockdown impaired locomotion and led to wing posture defects, supporting a role for TRAPPC6B in neuromotor function. Our findings confirm the association of damaging biallelic TRAPPC6B variants with microcephaly, intellectual disability, language impairments, and epilepsy. A subset of patients also exhibited dystonia and/or spasticity with impaired ambulation. These features overlap with disorders arising from pathogenic variants in other TRAPP subunits, particularly components of the TRAPP II complex. These findings suggest that TRAPPC6B is essential for brain development and function, and TRAPP II complex activity may be particularly relevant for mediating this function.
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Affiliation(s)
- Hashem Almousa
- Department of Biology, Concordia University, Montreal, Quebec H4B1R6, Canada
| | - Sara A Lewis
- Barrow Neurological Institute, Phoenix Children’s Hospital, Phoenix, AZ 85016, USA
- Departments of Child Health, Cellular and Molecular Medicine, Genetics, and Neurology, University of Arizona College of Medicine—Phoenix, Phoenix, AZ 85004, USA
| | - Somayeh Bakhtiari
- Barrow Neurological Institute, Phoenix Children’s Hospital, Phoenix, AZ 85016, USA
- Departments of Child Health, Cellular and Molecular Medicine, Genetics, and Neurology, University of Arizona College of Medicine—Phoenix, Phoenix, AZ 85004, USA
| | - Sandra Hinz Nordlie
- Barrow Neurological Institute, Phoenix Children’s Hospital, Phoenix, AZ 85016, USA
- Departments of Child Health, Cellular and Molecular Medicine, Genetics, and Neurology, University of Arizona College of Medicine—Phoenix, Phoenix, AZ 85004, USA
| | - Alex Pagnozzi
- CSIRO Health and Biosecurity, The Australian e-Health Research Centre, Brisbane 4029, Australia
| | - Helen Magee
- Barrow Neurological Institute, Phoenix Children’s Hospital, Phoenix, AZ 85016, USA
- Departments of Child Health, Cellular and Molecular Medicine, Genetics, and Neurology, University of Arizona College of Medicine—Phoenix, Phoenix, AZ 85004, USA
| | - Stephanie Efthymiou
- Department of Neuromuscular Disorders, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK
| | - Jennifer A Heim
- Barrow Neurological Institute, Phoenix Children’s Hospital, Phoenix, AZ 85016, USA
| | - Patricia Cornejo
- Pediatric Neuroradiology Division, Pediatric Radiology, Barrow Neurological Institute, Phoenix Children’s Hospital, Phoenix, AZ 85016, USA
- Department of Child Health, University of Arizona College of Medicine, Phoenix, AZ 85004, USA
- Department of Radiology, Mayo Clinic, Scottsdale, AZ 85259, USA
| | - Maha S Zaki
- Clinical Genetics Department, Human Genetics and Genome Research Division, National Research Centre, Cairo 12622, Egypt
- Genetics Department, Armed Forces College of Medicine (AFCM), Cairo 4460015, Egypt
| | - Najwa Anwar
- Department of Developmental-Behavioural Paediatrics, The Children's Hospital and Institute of Child Health, Lahore 54000, Pakistan
| | - Shazia Maqbool
- Department of Developmental-Behavioural Paediatrics, The Children's Hospital and Institute of Child Health, Lahore 54000, Pakistan
| | - Fatima Rahman
- Department of Developmental-Behavioural Paediatrics, The Children's Hospital and Institute of Child Health, Lahore 54000, Pakistan
| | - Derek E Neilson
- Genetics and Metabolism, Phoenix Children’s Hospital, Phoenix, AZ 85016, USA
| | - Anusha Vemuri
- Department of Pathology, University of Chicago, Chicago, IL 60637, USA
| | - Sheng Chih Jin
- Department of Genetics, Washington University, St.Louis, MO 63110, USA
| | - Xiao-Ru Yang
- Department of Medical Genetics and Alberta Children’s Hospital Research Institute, Cumming School of Medicine, University of Calgary, S.W. Calgary, AB T2N 4N1, Canada
| | - Abolfazl Heidari
- Reference Laboratory, Qazvin Medical University, Qazvin 34148-33245, Iran
| | - Koen van Gassen
- Division of Laboratories, Pharmacy and Biomedical Genetics, Section of Clinical Genetics, University Medical Center Utrecht (UMCU), 3584 CX Utrecht, Netherlands
| | - Aurélien Trimouille
- Laboratoire de Génétique Moléculaire, Service de Génétique Médicale, CHU Bordeaux—Hôpital Pellegrin, Place Amélie Raba Léon, 33000 Bordeaux, France
| | - Christel Thauvin-Robinet
- Department of Genetics and Reference Center for Development Disorders and Intellectual Disabilities, FHU TRANSLAD, CHU Dijon Bourgogne, 21000 Dijon, France
- Unité Fontctionnelle d’Innovation diagnostiques des maladies rares, FHU TRANSLAD, CHU Dijon Bourgogne, 21000 Dijon, France
- GAD ‘Génétique des Anomalies du Développement’, INSERM-Université de Bourgogne UMR1231, 21078 Dijon, France
| | - James Liu
- Barrow Neurological Institute, Phoenix Children’s Hospital, Phoenix, AZ 85016, USA
- Departments of Child Health, Cellular and Molecular Medicine, Genetics, and Neurology, University of Arizona College of Medicine—Phoenix, Phoenix, AZ 85004, USA
| | - Ange-Line Bruel
- Unité Fontctionnelle d’Innovation diagnostiques des maladies rares, FHU TRANSLAD, CHU Dijon Bourgogne, 21000 Dijon, France
- GAD ‘Génétique des Anomalies du Développement’, INSERM-Université de Bourgogne UMR1231, 21078 Dijon, France
| | - Hoda Tomoum
- Department of Pediatrics, Ain Shams University, Cairo 11516, Egypt
| | | | - Mais O Hashem
- Department of Translational Genomics, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Centre, Riyadh 11211, Saudi Arabia
| | - Mehran Beiraghi Toosi
- Pediatric Neurology Department, Ghaem Hospital, Mashhad University of Medical Sciences, Mashhad 13944-91388, Iran
- Neuroscience Research Center, Mashhad University of Medical Science, Mashhad 13944-91388, Iran
| | - Ehsan Ghayoor Karimiani
- Molecular and Clinical Sciences Institute, St.George’s, University of London, London SW17 0RE, UK
| | - Gözde Yeşil
- Istanbul Medical Faculty Department of Medical Genetics, Istanbul University, Istanbul 34452, Turkey
| | - Lokesh Lingappa
- Pediatric Neurology, Rainbow Children Hospital, Hyderabad 500034, India
| | - Debangana Baruah
- Pediatric Neurology, Rainbow Children Hospital, Hyderabad 500034, India
| | - Farnoosh Ebrahimzadeh
- Department of Internal Medicine, Mashhad University of Medical Sciences, Mashhad 13944-91388, Iran
| | - Julien Van-Gils
- Division of Laboratories, Pharmacy and Biomedical Genetics, Section of Clinical Genetics, University Medical Center Utrecht (UMCU), 3584 CX Utrecht, Netherlands
| | - Laurence Faivre
- Department of Genetics and Reference Center for Development Disorders and Intellectual Disabilities, FHU TRANSLAD, CHU Dijon Bourgogne, 21000 Dijon, France
| | - Mina Zamani
- Department of Biology, Faculty of Science, Shahid Chamran University of Ahvaz, Ahvaz 6135783151, Iran
- Narges Medical Genetics and Prenatal Diagnosis Laboratory, Ahvaz 6155889467, Iran
| | - Hamid Galehdari
- Department of Biology, Faculty of Science, Shahid Chamran University of Ahvaz, Ahvaz 6135783151, Iran
| | - Saeid Sadeghian
- Department of Pediatric Neurology, Golestan Medical, Educational, and Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz 6135733118, Iran
| | - Gholamreza Shariati
- Narges Medical Genetics and Prenatal Diagnosis Laboratory, Ahvaz 6155889467, Iran
- Department of Medical Genetics, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz 6135733118, Iran
| | - Rahema Mohammad
- Department of Neuromuscular Disorders, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK
| | - Jasper van der Smagt
- Division of Laboratories, Pharmacy and Biomedical Genetics, Section of Clinical Genetics, University Medical Center Utrecht (UMCU), 3584 CX Utrecht, Netherlands
| | - Alya Qari
- Medical Genomics Department, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center, Riyadh 11564, Saudi Arabia
| | - John B Vincent
- Molecular Neuropsychiatry & Development (MiND) Lab, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON M6J 1H4, Canada
| | - A Micheil Innes
- Department of Medical Genetics and Alberta Children’s Hospital Research Institute, Cumming School of Medicine, University of Calgary, S.W. Calgary, AB T2N 4N1, Canada
| | - Ali Dursun
- Department of Pediatric Metabolism, Hacettepe University, Faculty of Medicine & Institute of Child Health, Ankara 06800, Turkey
| | - R Köksal Özgül
- Department of Pediatric Metabolism, Hacettepe University, Faculty of Medicine & Institute of Child Health, Ankara 06800, Turkey
| | - Halil Tuna Akar
- Department of Pediatric Metabolism, Hacettepe University, Faculty of Medicine & Institute of Child Health, Ankara 06800, Turkey
| | - Kaya Bilguvar
- Department of Medical Genetics, Acibadem Mehmet Ali Aydinlar University, Istanbul 34752, Turkey
- Department of Neurosurgery and Genetics, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Cyril Mignot
- Département de Génétique, APHP Sorbonne Université, Hôpital Trousseau & Groupe Hospitalier Pitié-Salpêtrière, 75013 Paris, France
- Centre de Référence Déficiences Intellectuelles de Causes Rares, 75012 Paris, France
| | - Boris Keren
- Département de Génétique, APHP Sorbonne Université, Hôpital Trousseau & Groupe Hospitalier Pitié-Salpêtrière, 75013 Paris, France
| | - Claudia Raveli
- APHP Sorbonne Université, Service de Neuropédiatrie, Hôpital Trousseau, 75012 Paris, France
| | - Lydie Burglen
- Département de Génétique, Centre de référence des malformations et maladies congénitales du cervelet, APHP. Sorbonne Université, Hôpital Trousseau, 75012 Paris, France
| | - Alexandra Afenjar
- Département de Génétique, Centre de référence des malformations et maladies congénitales du cervelet, APHP. Sorbonne Université, Hôpital Trousseau, 75012 Paris, France
| | - Laura Donker Kaat
- Department of Clinical Genetics, Erasmus Medical Center, 3000 Rotterdam, The Netherlands
| | | | - Fowzan Alkuraya
- Department of Translational Genomics, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Centre, Riyadh 11211, Saudi Arabia
| | - Henry Houlden
- Department of Neuromuscular Disorders, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK
| | - Sergio Padilla-Lopez
- Barrow Neurological Institute, Phoenix Children’s Hospital, Phoenix, AZ 85016, USA
- Departments of Child Health, Cellular and Molecular Medicine, Genetics, and Neurology, University of Arizona College of Medicine—Phoenix, Phoenix, AZ 85004, USA
| | - Reza Maroofian
- Department of Neuromuscular Disorders, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK
| | - Michael Sacher
- Department of Biology, Concordia University, Montreal, Quebec H4B1R6, Canada
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec H3A0C7, Canada
| | - Michael C Kruer
- Barrow Neurological Institute, Phoenix Children’s Hospital, Phoenix, AZ 85016, USA
- Departments of Child Health, Cellular and Molecular Medicine, Genetics, and Neurology, University of Arizona College of Medicine—Phoenix, Phoenix, AZ 85004, USA
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Chen X, Liang Y. Vtc4 Promotes the Entry of Phagophores into Vacuoles in the Saccharomyces cerevisiae Snf7 Mutant Cell. J Fungi (Basel) 2023; 9:1003. [PMID: 37888259 PMCID: PMC10607680 DOI: 10.3390/jof9101003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 10/03/2023] [Accepted: 10/09/2023] [Indexed: 10/28/2023] Open
Abstract
Endocytosis and autophagy are the main pathways to deliver cargoes in vesicles and autophagosomes, respectively, to vacuoles/lysosomes in eukaryotes. Multiple positive regulators but few negative ones are reported to regulate the entry of vesicles and autophagosomes into vacuoles/lysosomes. In yeast, the Rab5 GTPase Vps21 and the ESCRT (endosomal sorting complex required for transport) are positive regulators in endocytosis and autophagy. During autophagy, Vps21 regulates the ESCRT to phagophores (unclosed autophagosomes) to close them. Phagophores accumulate on vacuolar membranes in both vps21∆ and ESCRT mutant cells under a short duration of nitrogen starvation. The vacuolar transport chaperon (VTC) complex proteins are recently found to be negative regulators in endocytosis and autophagy. Phagophores in vps21∆ cells are promoted to enter vacuoles when the VTC complex proteins are absent. Phagophores are easily observed inside vacuoles when any of these VTC complex proteins (Vtc1, 2, 4, 5) are removed. However, it is unknown whether the removal of VTC complex proteins will also promote the entry of phagophores into vacuoles in ESCRT mutant cells under the same conditions. Snf7 is a core subunit of ESCRT subcomplex III (ESCRT-III), and phagophores accumulate in snf7∆ cells under a short duration of nitrogen starvation. We used green fluorescence protein (GFP) labeled Atg8 to display phagophores and FM4-64-stained or Vph1-GFP-labeled membrane structures to show vacuoles, then examined fluorescence localization and GFP-Atg8 degradation in snf7∆ and snf7∆vtc4∆ cells. Results showed that Vtc4 depletion promoted the entry of phagophores in snf7∆ cells into vacuoles as it did for vps21∆ cells, although the promotion level was more obvious in vps21∆ cells. This observation indicates that the VTC complex proteins may have a widespread role in negatively regulating cargos to enter vacuoles in yeast.
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Affiliation(s)
| | - Yongheng Liang
- Key Laboratory of Agricultural Environmental Microbiology of Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China;
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Ma D, Yu M, Eszterhas S, Rollenhagen C, Lee SA. A C. albicans TRAPP Complex-Associated Gene Contributes to Cell Wall Integrity, Hyphal and Biofilm Formation, and Tissue Invasion. Microbiol Spectr 2023; 11:e0536122. [PMID: 37222596 PMCID: PMC10269527 DOI: 10.1128/spectrum.05361-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Accepted: 05/08/2023] [Indexed: 05/25/2023] Open
Abstract
While endocytic and secretory pathways are well-studied cellular processes in the model yeast Saccharomyces cerevisiae, they remain understudied in the opportunistic fungal pathogen Candida albicans. We previously found that null mutants of C. albicans homologs of the S. cerevisiae early endocytosis genes ENT2 and END3 not only exhibited delayed endocytosis but also had defects in cell wall integrity, filamentation, biofilm formation, extracellular protease activity, and tissue invasion in an in vitro model. In this study, we focused on a potential C. albicans homolog to S. cerevisiae TCA17, which was discovered in our whole-genome bioinformatics approach aimed at identifying genes involved in endocytosis. In S. cerevisiae, TCA17 encodes a transport protein particle (TRAPP) complex-associated protein. Using a reverse genetics approach with CRISPR-Cas9-mediated gene deletion, we analyzed the function of the TCA17 homolog in C. albicans. Although the C. albicans tca17Δ/Δ null mutant did not have defects in endocytosis, it displayed an enlarged cell and vacuole morphology, impaired filamentation, and reduced biofilm formation. Moreover, the mutant exhibited altered sensitivity to cell wall stressors and antifungal agents. When assayed using an in vitro keratinocyte infection model, virulence properties were also diminished. Our findings indicate that C. albicans TCA17 may be involved in secretion-related vesicle transport and plays a role in cell wall and vacuolar integrity, hyphal and biofilm formation, and virulence. IMPORTANCE The fungal pathogen Candida albicans causes serious opportunistic infections in immunocompromised patients and has become a major cause of hospital-acquired bloodstream infections, catheter-associated infections, and invasive disease. However, due to a limited understanding of Candida molecular pathogenesis, clinical approaches for the prevention, diagnosis, and treatment of invasive candidiasis need significant improvement. In this study, we focus on identifying and characterizing a gene potentially involved in the C. albicans secretory pathway, as intracellular transport is critical for C. albicans virulence. We specifically investigated the role of this gene in filamentation, biofilm formation, and tissue invasion. Ultimately, these findings advance our current understanding of C. albicans biology and may have implications for the diagnosis and treatment of candidiasis.
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Affiliation(s)
- Dakota Ma
- Medicine Service, White River Junction VA Medical Center, Hartford, Vermont, USA
- Dartmouth College, Hanover, New Hampshire, USA
| | - Miranda Yu
- Medicine Service, White River Junction VA Medical Center, Hartford, Vermont, USA
- Dartmouth College, Hanover, New Hampshire, USA
| | - Susan Eszterhas
- Medicine Service, White River Junction VA Medical Center, Hartford, Vermont, USA
- Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Christiane Rollenhagen
- Medicine Service, White River Junction VA Medical Center, Hartford, Vermont, USA
- Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Samuel A. Lee
- Medicine Service, White River Junction VA Medical Center, Hartford, Vermont, USA
- Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
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Vps21 Directs the PI3K-PI(3)P-Atg21-Atg16 Module to Phagophores via Vps8 for Autophagy. Int J Mol Sci 2022; 23:ijms23179550. [PMID: 36076954 PMCID: PMC9455592 DOI: 10.3390/ijms23179550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Revised: 08/20/2022] [Accepted: 08/21/2022] [Indexed: 11/28/2022] Open
Abstract
Phosphatidylinositol 3-phosphate (PI(3)P) serves important functions in endocytosis, phagocytosis, and autophagy. PI(3)P is generated by Vps34 of the class III phosphatidylinositol 3-kinase (PI3K) complex. The Vps34-PI3K complex can be divided into Vps34-PI3K class II (containing Vps38, endosomal) and Vps34-PI3K class I (containing Atg14, autophagosomal). Most PI(3)Ps are associated with endosomal membranes. In yeast, the endosomal localization of Vps34 and PI(3)P is tightly regulated by Vps21-module proteins. At yeast phagophore assembly site (PAS) or mammalian omegasomes, PI(3)P binds to WD-repeat protein interacting with phosphoinositide (WIPI) proteins to further recruit two conjugation systems, Atg5-Atg12·Atg16 and Atg8-PE (LC3-II), to initiate autophagy. However, the spatiotemporal regulation of PI(3)P during autophagy remains obscure. Therefore, in this study, we determined the effect of Vps21 on localization and interactions of Vps8, Vps34, Atg21, Atg8, and Atg16 upon autophagy induction. The results showed that Vps21 was required for successive colocalizations and interactions of Vps8-Vps34 and Vps34-Atg21 on endosomes, and Atg21-Atg8/Atg16 on the PAS. In addition to disrupted localization of the PI3K complex II subunits Vps34 and Vps38 on endosomes, the localization of the PI3K complex I subunits Vps34 and Atg14, as well as Atg21, was partly disrupted from the PAS in vps21∆ cells. The impaired PI3K-PI(3)P-Atg21-Atg16 axis in vps21∆ cells might delay autophagy, which is consistent with the delay of early autophagy when Atg21 was absent. This study provides the first insight into the upstream sequential regulation of the PI3K-PI(3)P-Atg21-Atg16 module by Vps21 in autophagy.
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Mi C, Zhang L, Huang G, Shao G, Yang F, You X, Dong MQ, Sun S, Sui SF. Structural basis for assembly of TRAPPII complex and specific activation of GTPase Ypt31/32. SCIENCE ADVANCES 2022; 8:eabi5603. [PMID: 35080977 PMCID: PMC8791620 DOI: 10.1126/sciadv.abi5603] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 12/02/2021] [Indexed: 06/14/2023]
Abstract
Transport protein particle (TRAPP) complexes belong to the multiprotein tethering complex and exist in three forms-core TRAPP/TRAPPI, TRAPPII, and TRAPPIII. TRAPPII activates GTPase Ypt31/Ypt32 as the guanine nucleotide exchange factor in the trans-Golgi network to determine the maturation of Golgi cisternae into post-Golgi carriers in yeast. Here, we present cryo-EM structures of yeast TRAPPII in apo and Ypt32-bound states. All the structures show a dimeric architecture assembled by two triangle-shaped monomers, while the monomer in the apo state exhibits both open and closed conformations, and the monomer in the Ypt32-bound form only captures the closed conformation. Located in the interior of the monomer, Ypt32 binds with both core TRAPP/TRAPPI and Trs120 via its nucleotide-binding domain and binds with Trs31 via its hypervariable domain. Combined with functional analysis, the structures provide insights into the assembly of TRAPPII and the mechanism of the specific activation of Ypt31/Ypt32 by TRAPPII.
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Affiliation(s)
- Chenchen Mi
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Li Zhang
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Guoqiang Huang
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Guangcan Shao
- National Institute of Biological Sciences, Beijing 102206, China
| | - Fan Yang
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Xin You
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Meng-Qiu Dong
- National Institute of Biological Sciences, Beijing 102206, China
| | - Shan Sun
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Sen-Fang Sui
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing 100084, China
- Department of Biology, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
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Liu D, Luo Y, Zheng X, Wang X, Chou M, Wei G. TRAPPC13 Is a Novel Target of Mesorhizobium amorphae Type III Secretion System Effector NopP. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2021; 34:511-523. [PMID: 33630651 DOI: 10.1094/mpmi-12-20-0354-fi] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Similar to pathogenic bacteria, rhizobia can inject effector proteins into host cells directly to promote infection via the type III secretion system (T3SS). Nodulation outer protein P (NopP), a specific T3SS effector of rhizobia, plays different roles in the establishment of multiple rhizobia-legume symbiotic systems. Mesorhizobium amorphae CCNWGS0123 (GS0123), which infects Robinia pseudoacacia specifically, secretes several T3SS effectors, including NopP. Here, we demonstrate that NopP is secreted through T3SS-I of GS0123 during the early stages of infection, and its deficiency decreases nodule nitrogenase activity of R. pseudoacacia nodules. A trafficking protein particle complex subunit 13-like protein (TRAPPC13) has been identified as a NopP target protein in R. pseudoacacia roots by screening a yeast two-hybrid library. The physical interaction between NopP and TRAPPC13 is verified by bimolecular fluorescence complementation and coimmunoprecipitation assays. In addition, subcellular localization analysis reveals that both NopP and its target, TRAPPC13, are colocalized on the plasma membrane. Compared with GS0123-inoculated R. pseudoacacia roots, some genes associated with cell wall remodeling and plant innate immunity down-regulated in ΔnopP-inoculated roots at 36 h postinoculation. The results suggest that NopP in M. amorphae CCNWGS0123 acts in multiple processes in R. pseudoacacia during the early stages of infection, and TRAPPC13 could participate in the process as a NopP target.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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Affiliation(s)
- Dongying Liu
- State Key Laboratory of Crop Stress Biology in Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Yantao Luo
- State Key Laboratory of Crop Stress Biology in Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Xiaofeng Zheng
- Shaanxi Hydrogeology Engineering Geology and Environmental Geology Survey Center, Shaanxi Institute of Geological Survey, Xi'an, Shaanxi 710054, China
| | - Xinye Wang
- Moutai Institute, Renhuai, Guizhou 564500, China
| | - Minxia Chou
- State Key Laboratory of Crop Stress Biology in Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Gehong Wei
- State Key Laboratory of Crop Stress Biology in Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China
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7
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Jenkins ML, Harris NJ, Dalwadi U, Fleming KD, Ziemianowicz DS, Rafiei A, Martin EM, Schriemer DC, Yip CK, Burke JE. The substrate specificity of the human TRAPPII complex's Rab-guanine nucleotide exchange factor activity. Commun Biol 2020; 3:735. [PMID: 33277614 PMCID: PMC7719173 DOI: 10.1038/s42003-020-01459-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Accepted: 10/13/2020] [Indexed: 12/15/2022] Open
Abstract
The TRAnsport Protein Particle (TRAPP) complexes act as Guanine nucleotide exchange factors (GEFs) for Rab GTPases, which are master regulators of membrane trafficking in eukaryotic cells. In metazoans, there are two large multi-protein TRAPP complexes: TRAPPII and TRAPPIII, with the TRAPPII complex able to activate both Rab1 and Rab11. Here we present detailed biochemical characterisation of Rab-GEF specificity of the human TRAPPII complex, and molecular insight into Rab binding. GEF assays of the TRAPPII complex against a panel of 20 different Rab GTPases revealed GEF activity on Rab43 and Rab19. Electron microscopy and chemical cross-linking revealed the architecture of mammalian TRAPPII. Hydrogen deuterium exchange MS showed that Rab1, Rab11 and Rab43 share a conserved binding interface. Clinical mutations in Rab11, and phosphomimics of Rab43, showed decreased TRAPPII GEF mediated exchange. Finally, we designed a Rab11 mutation that maintained TRAPPII-mediated GEF activity while decreasing activity of the Rab11-GEF SH3BP5, providing a tool to dissect Rab11 signalling. Overall, our results provide insight into the GTPase specificity of TRAPPII, and how clinical mutations disrupt this regulation. Here the authors reveal unique structural organization of the mammalian TRAPPII complex, which is critical in regulating membrane trafficking. They find that TRAPPII serves as a guanine nucleotide exchange factor for unexpected Rab GTPases such as Rab43 and Rab19.
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Affiliation(s)
- Meredith L Jenkins
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, V8W 2Y2, Canada
| | - Noah J Harris
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, V8W 2Y2, Canada
| | - Udit Dalwadi
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Kaelin D Fleming
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, V8W 2Y2, Canada
| | - Daniel S Ziemianowicz
- Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, AB, T2N 4N1, Canada
| | - Atefeh Rafiei
- Department of Chemistry, University of Calgary, Calgary, AB, T2N 4N1, Canada
| | - Emily M Martin
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, V8W 2Y2, Canada
| | - David C Schriemer
- Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, AB, T2N 4N1, Canada.,Department of Chemistry, University of Calgary, Calgary, AB, T2N 4N1, Canada
| | - Calvin K Yip
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - John E Burke
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, V8W 2Y2, Canada. .,Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, V6T 1Z3, Canada.
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8
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Bodnar B, DeGruttola A, Zhu Y, Lin Y, Zhang Y, Mo X, Hu W. Emerging role of NIK/IKK2-binding protein (NIBP)/trafficking protein particle complex 9 (TRAPPC9) in nervous system diseases. Transl Res 2020; 224:55-70. [PMID: 32434006 PMCID: PMC7442628 DOI: 10.1016/j.trsl.2020.05.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 05/02/2020] [Accepted: 05/05/2020] [Indexed: 02/05/2023]
Abstract
NFκB signaling and protein trafficking network play important roles in various biological and pathological processes. NIK-and-IKK2-binding protein (NIBP), also known as trafficking protein particle complex 9 (TRAPPC9), is a prototype member of a novel protein family, and has been shown to regulate both NFκB signaling pathway and protein transport/trafficking. NIBP is extensively expressed in the nervous system and plays an important role in regulating neurogenesis and neuronal differentiation. NIBP/TRAPPC9 mutations have been linked to an autosomal recessive intellectual disability syndrome, called NIBP Syndrome, which is characterized by nonsyndromic autosomal recessive intellectual disability along with other symptoms such as obesity, microcephaly, and facial dysmorphia. As more cases of NIBP Syndrome are identified, new light is being shed on the role of NIBP/TRAPPC9 in the central nervous system developments and diseases. NIBP is also involved in the enteric nervous system. This review will highlight the importance of NIBP/TRAPPC9 in central and enteric nervous system diseases, and the established possible mechanisms for developing a potential therapeutic.
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Affiliation(s)
- Brittany Bodnar
- Center for Metabolic Disease Research, Temple University Lewis Katz School of Medicine, Philadelphia, Pennsylvania; MD/PhD and Biomedical Sciences Graduate Program, Temple University Lewis Katz School of Medicine, Philadelphia, Pennsylvania
| | - Arianna DeGruttola
- Center for Metabolic Disease Research, Temple University Lewis Katz School of Medicine, Philadelphia, Pennsylvania; MD/PhD and Biomedical Sciences Graduate Program, Temple University Lewis Katz School of Medicine, Philadelphia, Pennsylvania
| | - Yuanjun Zhu
- Center for Metabolic Disease Research, Temple University Lewis Katz School of Medicine, Philadelphia, Pennsylvania; Department of Pathology and Laboratory Medicine, Temple University Lewis Katz School of Medicine, Philadelphia, Pennsylvania; Department of Molecular and Cellular Pharmacology, Peking University School of Pharmaceutical Sciences, Beijing, China
| | - Yuan Lin
- Center for Metabolic Disease Research, Temple University Lewis Katz School of Medicine, Philadelphia, Pennsylvania; Department of Pathology and Laboratory Medicine, Temple University Lewis Katz School of Medicine, Philadelphia, Pennsylvania
| | - Yonggang Zhang
- Center for Stem Cell Research and Application, Institute of Blood Transfusion, Chinese Academy of Medical Sciences & Peking Union Medical College (CAMS & PUMC), Chengdu, China
| | - Xianming Mo
- Laboratory of Stem Cell Biology, State Key Laboratory of Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu, China
| | - Wenhui Hu
- Center for Metabolic Disease Research, Temple University Lewis Katz School of Medicine, Philadelphia, Pennsylvania; MD/PhD and Biomedical Sciences Graduate Program, Temple University Lewis Katz School of Medicine, Philadelphia, Pennsylvania; Department of Pathology and Laboratory Medicine, Temple University Lewis Katz School of Medicine, Philadelphia, Pennsylvania.
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9
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Garcia VJ, Xu SL, Ravikumar R, Wang W, Elliott L, Gonzalez E, Fesenko M, Altmann M, Brunschweiger B, Falter-Braun P, Moore I, Burlingame A, Assaad FF, Wang ZY. TRIPP Is a Plant-Specific Component of the Arabidopsis TRAPPII Membrane Trafficking Complex with Important Roles in Plant Development. THE PLANT CELL 2020; 32:2424-2443. [PMID: 32371545 PMCID: PMC7346556 DOI: 10.1105/tpc.20.00044] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 03/25/2020] [Accepted: 04/23/2020] [Indexed: 05/23/2023]
Abstract
How the membrane trafficking system spatially organizes intracellular activities and intercellular signaling networks in plants is not well understood. Transport Protein Particle (TRAPP) complexes play key roles in the selective delivery of membrane vesicles to various subcellular compartments in yeast and animals but remain to be fully characterized in plants. Here, we investigated TRAPP complexes in Arabidopsis (Arabidopsis thaliana) using immunoprecipitation followed by quantitative mass spectrometry analysis of AtTRS33, a conserved core component of all TRAPP complexes. We identified 14 AtTRS33-interacting proteins, including homologs of all 13 TRAPP components in mammals and a protein that has homologs only in multicellular photosynthetic organisms and is thus named TRAPP-Interacting Plant Protein (TRIPP). TRIPP specifically associates with the TRAPPII complex through binary interactions with two TRAPPII-specific subunits. TRIPP colocalized with a subset of TRS33 compartments and trans-Golgi network markers in a TRS33-dependent manner. Loss-of-function tripp mutants exhibited dwarfism, sterility, partial photomorphogenesis in the dark, reduced polarity of the auxin transporter PIN2, incomplete cross wall formation, and altered localization of a TRAPPII-specific component. Therefore, TRIPP is a plant-specific component of the TRAPPII complex with important functions in trafficking, plant growth, and development.
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Affiliation(s)
- Veder J Garcia
- Department of Plant Biology, Carnegie Institution for Science, Stanford, California 94305
| | - Shou-Ling Xu
- Department of Plant Biology, Carnegie Institution for Science, Stanford, California 94305
| | - Raksha Ravikumar
- Plant Science Department, Botany, Technische Universität München, 85354 Freising, Germany
| | - Wenfei Wang
- Basic Forestry and Proteomics Research Center, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Liam Elliott
- Department of Plant Sciences, University of Oxford, Oxford, OX1 3RB, United Kingdom
| | - Efren Gonzalez
- Department of Plant Biology, Carnegie Institution for Science, Stanford, California 94305
| | - Mary Fesenko
- Department of Plant Sciences, University of Oxford, Oxford, OX1 3RB, United Kingdom
| | - Melina Altmann
- Institute of Network Biology, Helmholtz Zentrum München, Deutsches Forschungszentrum für Gesundheit und Umwelt, 85764 Neuherberg, Germany
| | - Barbara Brunschweiger
- Plant Science Department, Botany, Technische Universität München, 85354 Freising, Germany
| | - Pascal Falter-Braun
- Institute of Network Biology, Helmholtz Zentrum München, Deutsches Forschungszentrum für Gesundheit und Umwelt, 85764 Neuherberg, Germany
- Faculty of Biology, Microbe-Host-Interactions, Ludwig-Maximilians-Universität München, 82152 Planegg-Martinsried, Germany
| | - Ian Moore
- Department of Plant Sciences, University of Oxford, Oxford, OX1 3RB, United Kingdom
| | - Alma Burlingame
- Department of Pharmaceutical Chemistry, University of California, San Francisco, California 94158
| | - Farhah F Assaad
- Plant Science Department, Botany, Technische Universität München, 85354 Freising, Germany
| | - Zhi-Yong Wang
- Department of Plant Biology, Carnegie Institution for Science, Stanford, California 94305
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10
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Zhang J, Chen J, Wang L, Zhao S, Wang W, Li J, Liu B, Qi X, Zheng H, Lu M. An essential role for Arabidopsis Trs33 in cell growth and organization in plant apical meristems. PLANT CELL REPORTS 2020; 39:381-391. [PMID: 31828377 DOI: 10.1007/s00299-019-02497-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 12/02/2019] [Indexed: 06/10/2023]
Abstract
Trafficking protein particle (TRAPP) complexes subunit gene AtTrs33 plays an important role in keeping apical meristematic activity and dominance in Arabidopsis. TRAPP complexes, composed of multimeric subunits, are guanine-nucleotide exchange factors for certain Rab GTPases and are believed to be involved in the regulation of membrane trafficking, but the cases in Arabidopsis are largely unknown. Trs33, recently proposed to be a component of TRAPP IV, is non-essential in yeast cells. A single copy of Trs33 gene, AtTrs33, was identified in Arabidopsis. GUS activity assay indicated that AtTrs33 was ubiquitously expressed. Based on a T-DNA insertion line, we found that loss-of-function of AtTrs33 is lethal for apical growth. Knock-down or knock-in of AtTrs33 affects apical meristematic growth and fertility, which indicates that AtTrs33 plays an important role in keeping apical meristematic activity and dominance in Arabidopsis. Analysis of auxin responses and PIN1/2 localization indicate that impaired apical meristematic activity and dominance were caused by altered auxin responses through non-polarized PIN1 localization. The present study reported that AtTrs33 plays an essential role in Arabidopsis cell growth and organization, which is different with its homologue in yeast. These findings provide new insights into the functional divergence of TRAPP subunits.
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Affiliation(s)
- Jin Zhang
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of the State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100 091, China
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Jun Chen
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of the State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100 091, China
- Department of Biology, McGill University, 1205 Dr Penfield Avenue, Montreal, QC, H3A 1B1, Canada
| | - Lijuan Wang
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of the State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100 091, China
| | - Shutang Zhao
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of the State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100 091, China
| | - Weina Wang
- Department of Biology, McGill University, 1205 Dr Penfield Avenue, Montreal, QC, H3A 1B1, Canada
| | - Jianbo Li
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of the State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100 091, China
| | - Bobin Liu
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of the State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100 091, China
| | - Xingyun Qi
- Department of Biology, McGill University, 1205 Dr Penfield Avenue, Montreal, QC, H3A 1B1, Canada
| | - Huanquan Zheng
- Department of Biology, McGill University, 1205 Dr Penfield Avenue, Montreal, QC, H3A 1B1, Canada.
| | - Mengzhu Lu
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of the State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100 091, China.
- State Key Laboratory of Subtropical Silviculture, School of Forestry and Biotechnology, Zhejiang A&F University, Hanzhou, Zhejiang, 311300, China.
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11
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Pinar M, Arias-Palomo E, de los Ríos V, Arst HN, Peñalva MA. Characterization of Aspergillus nidulans TRAPPs uncovers unprecedented similarities between fungi and metazoans and reveals the modular assembly of TRAPPII. PLoS Genet 2019; 15:e1008557. [PMID: 31869332 PMCID: PMC6946167 DOI: 10.1371/journal.pgen.1008557] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 01/07/2020] [Accepted: 12/06/2019] [Indexed: 12/22/2022] Open
Abstract
TRAnsport Protein Particle complexes (TRAPPs) are ubiquitous regulators of membrane traffic mediating nucleotide exchange on the Golgi regulatory GTPases RAB1 and RAB11. In S. cerevisiae and metazoans TRAPPs consist of two large oligomeric complexes: RAB11-activating TRAPPII and RAB1-activating TRAPPIII. These share a common core TRAPPI hetero-heptamer, absent in metazoans but detected in minor proportions in yeast, likely originating from in vitro-destabilized TRAPPII/III. Despite overall TRAPP conservation, the budding yeast genome has undergone extensive loss of genes, and lacks homologues of some metazoan TRAPP subunits. With nearly twice the total number of genes of S. cerevisiae, another ascomycete Aspergillus nidulans has also been used for studies on TRAPPs. We combined size-fractionation chromatography with single-step purification coupled to mass-spectrometry and negative-stain electron microscopy to establish the relative abundance, composition and architecture of Aspergillus TRAPPs, which consist of TRAPPII and TRAPPIII in a 2:1 proportion, plus a minor amount of TRAPPI. We show that Aspergillus TRAPPIII contains homologues of metazoan TRAPPC11, TRAPPC12 and TRAPPC13 subunits, absent in S. cerevisiae, and establish that these subunits are recruited to the complex by Tca17/TRAPPC2L, which itself binds to the ‘Trs33 side’ of the complex. Thus Aspergillus TRAPPs compositionally resemble mammalian TRAPPs to a greater extent than those in budding yeast. Exploiting the ability of constitutively-active (GEF-independent, due to accelerated GDP release) RAB1* and RAB11* alleles to rescue viability of null mutants lacking essential TRAPP subunits, we establish that the only essential role of TRAPPs is activating RAB1 and RAB11, and genetically classify each essential subunit according to their role(s) in TRAPPII (TRAPPII-specific subunits) or TRAPPII and TRAPPIII (core TRAPP subunits). Constitutively-active RAB mutant combinations allowed examination of TRAPP composition in mutants lacking essential subunits, which led to the discovery of a stable Trs120/Trs130/Trs65/Tca17 TRAPPII-specific subcomplex whose Trs20- and Trs33-dependent assembly onto core TRAPP generates TRAPPII. TRAPPs govern intracellular traffic across eukaryotes, activating the Golgi GTPases RAB1 and RAB11. Other genetically tractable fungi are emerging as alternatives to baker’s yeast for cell-biological studies. We exploit Aspergillus nidulans, a filamentous ascomycete that has a lifestyle highly demanding for exocytosis and, that unlike baker’s yeast, has not undergone extensive gene loss. We show that fungal and metazoan TRAPPs are more similar than previously thought, after identifying three A. nidulans subunits previously believed exclusive to metazoans and demonstrating that TRAPPI is very minor, if it exists at all. Also importantly we classified, using a novel genetic approach, essential TRAPP subunits according to their role in activating RAB1 and/or RAB11, which demonstrated that the only indispensable role for TRAPPs is mediating nucleotide exchange on these GTPases and led to the discovery of a stable four-subunit subcomplex that assembles onto the also stable seven-subunit core to form the TRAPPII holocomplex.
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Affiliation(s)
- Mario Pinar
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas CSIC, Madrid, Spain
| | - Ernesto Arias-Palomo
- Department of Structural and Chemical Biology, Centro de Investigaciones Biológicas CSIC, Madrid, Spain
| | - Vivian de los Ríos
- Proteomics Facility, Centro de Investigaciones Biológicas CSIC, Madrid, Spain
| | - Herbert N. Arst
- Section of Microbiology, Imperial College London, London, United Kingdom
| | - Miguel A. Peñalva
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas CSIC, Madrid, Spain
- * E-mail:
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12
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Kalde M, Elliott L, Ravikumar R, Rybak K, Altmann M, Klaeger S, Wiese C, Abele M, Al B, Kalbfuß N, Qi X, Steiner A, Meng C, Zheng H, Kuster B, Falter-Braun P, Ludwig C, Moore I, Assaad FF. Interactions between Transport Protein Particle (TRAPP) complexes and Rab GTPases in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2019; 100:279-297. [PMID: 31264742 DOI: 10.1111/tpj.14442] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 05/15/2019] [Accepted: 06/11/2019] [Indexed: 05/23/2023]
Abstract
Transport Protein Particle II (TRAPPII) is essential for exocytosis, endocytosis, protein sorting and cytokinesis. In spite of a considerable understanding of its biological role, little information is known about Arabidopsis TRAPPII complex topology and molecular function. In this study, independent proteomic approaches initiated with TRAPP components or Rab-A GTPase variants converge on the TRAPPII complex. We show that the Arabidopsis genome encodes the full complement of 13 TRAPPC subunits, including four previously unidentified components. A dimerization model is proposed to account for binary interactions between TRAPPII subunits. Preferential binding to dominant negative (GDP-bound) versus wild-type or constitutively active (GTP-bound) RAB-A2a variants discriminates between TRAPPII and TRAPPIII subunits and shows that Arabidopsis complexes differ from yeast but resemble metazoan TRAPP complexes. Analyzes of Rab-A mutant variants in trappii backgrounds provide genetic evidence that TRAPPII functions upstream of RAB-A2a, allowing us to propose that TRAPPII is likely to behave as a guanine nucleotide exchange factor (GEF) for the RAB-A2a GTPase. GEFs catalyze exchange of GDP for GTP; the GTP-bound, activated, Rab then recruits a diverse local network of Rab effectors to specify membrane identity in subsequent vesicle fusion events. Understanding GEF-Rab interactions will be crucial to unravel the co-ordination of plant membrane traffic.
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Affiliation(s)
- Monika Kalde
- Department of Plant Sciences, University of Oxford, Oxford, OX1 3RB, UK
| | - Liam Elliott
- Department of Plant Sciences, University of Oxford, Oxford, OX1 3RB, UK
| | - Raksha Ravikumar
- Plant Science Department, Botany, Technische Universität München, Freising, 85354, Germany
| | - Katarzyna Rybak
- Plant Science Department, Botany, Technische Universität München, Freising, 85354, Germany
| | - Melina Altmann
- Institute of Network Biology (INET), Helmholtz Zentrum München, Deutsches Forschungszentrum für Gesundheit und Umwelt (GmbH), Neuherberg, 85764, Germany
| | - Susan Klaeger
- Chair of Proteomics and Bioanalytics, Technische Universität München, Freising, 85354, Germany
| | - Christian Wiese
- Plant Science Department, Botany, Technische Universität München, Freising, 85354, Germany
| | - Miriam Abele
- Plant Science Department, Botany, Technische Universität München, Freising, 85354, Germany
| | - Benjamin Al
- Plant Science Department, Botany, Technische Universität München, Freising, 85354, Germany
| | - Nils Kalbfuß
- Plant Science Department, Botany, Technische Universität München, Freising, 85354, Germany
| | - Xingyun Qi
- Department of Biology, McGill University, Montreal, H3B 1A1, Canada
| | - Alexander Steiner
- Plant Science Department, Botany, Technische Universität München, Freising, 85354, Germany
| | - Chen Meng
- BayBioMS, Bavarian Center for Biomolecular Mass Spectrometry, Technische Universität München, Freising, 85354, Germany
| | - Huanquan Zheng
- Department of Biology, McGill University, Montreal, H3B 1A1, Canada
| | - Bernhard Kuster
- Chair of Proteomics and Bioanalytics, Technische Universität München, Freising, 85354, Germany
| | - Pascal Falter-Braun
- Institute of Network Biology (INET), Helmholtz Zentrum München, Deutsches Forschungszentrum für Gesundheit und Umwelt (GmbH), Neuherberg, 85764, Germany
- Faculty of Biology, Microbe-Host-Interactions, Ludwig-Maximilians-Universität (LMU) München, Planegg-Martinsried, 82152, Germany
| | - Christina Ludwig
- BayBioMS, Bavarian Center for Biomolecular Mass Spectrometry, Technische Universität München, Freising, 85354, Germany
| | - Ian Moore
- Department of Plant Sciences, University of Oxford, Oxford, OX1 3RB, UK
| | - Farhah F Assaad
- Plant Science Department, Botany, Technische Universität München, Freising, 85354, Germany
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13
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Lipatova Z, Segev N. Ypt/Rab GTPases and their TRAPP GEFs at the Golgi. FEBS Lett 2019; 593:2488-2500. [PMID: 31400292 PMCID: PMC6989042 DOI: 10.1002/1873-3468.13574] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 08/07/2019] [Accepted: 08/08/2019] [Indexed: 11/06/2022]
Abstract
The conserved Ypt/Rab GTPases regulate the different steps of all intracellular trafficking pathways. Ypt/Rabs are activated by their specific nucleotide exchangers termed GEFs, and when GTP bound, they recruit their downstream effectors, which mediate vesicular transport substeps. In the yeast exocytic pathway, Ypt1 and Ypt31/32 regulate traffic through the Golgi and the conserved modular TRAPP complex acts a GEF for both Ypt1 and Ypt31/32. However, the precise localization and function of these Ypts have been under debate, as is the identity of their corresponding GEFs. We have established that Ypt1 and Ypt31 reside on the two sides of the Golgi, early and late, respectively, and regulate Golgi cisternal progression. We and others have shown that whereas a single TRAPP complex, TRAPP II, activates Ypt31, three TRAPP complexes can activate Ypt1: TRAPPs I, III, and IV. We propose that TRAPP I and II activate Ypt1 and Ypt31, respectively, at the Golgi, whereas TRAPP III and IV activate Ypt1 in autophagy. Resolving these issues is important because both Rabs and TRAPPs are implicated in multiple human diseases, ranging from cancer to neurodegenerative diseases.
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Affiliation(s)
- Zhanna Lipatova
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, IL, USA
| | - Nava Segev
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, IL, USA
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14
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Cuenca A, Insinna C, Zhao H, John P, Weiss MA, Lu Q, Walia V, Specht S, Manivannan S, Stauffer J, Peden AA, Westlake CJ. The C7orf43/TRAPPC14 component links the TRAPPII complex to Rabin8 for preciliary vesicle tethering at the mother centriole during ciliogenesis. J Biol Chem 2019; 294:15418-15434. [PMID: 31467083 DOI: 10.1074/jbc.ra119.008615] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 08/25/2019] [Indexed: 01/08/2023] Open
Abstract
The primary cilium is a cellular sensor that detects light, chemicals, and movement and is important for morphogen and growth factor signaling. The small GTPase Rab11-Rab8 cascade is required for ciliogenesis. Rab11 traffics the guanine nucleotide exchange factor (GEF) Rabin8 to the centrosome to activate Rab8, needed for ciliary growth. Rabin8 also requires the transport particle protein complex (TRAPPC) proteins for centrosome recruitment during ciliogenesis. Here, using an MS-based approach for identifying Rabin8-interacting proteins, we identified C7orf43 (also known as microtubule-associated protein 11 (MAP11)) as being required for ciliation both in human cells and zebrafish embryos. We find that C7orf43 directly binds to Rabin8 and that C7orf43 knockdown diminishes Rabin8 preciliary centrosome accumulation. Interestingly, we found that C7orf43 co-sediments with TRAPPII complex subunits and directly interacts with TRAPPC proteins. Our findings establish that C7orf43 is a TRAPPII-specific complex component, referred to here as TRAPPC14. Additionally, we show that TRAPPC14 is dispensable for TRAPPII complex integrity but mediates Rabin8 association with the TRAPPII complex. Finally, we demonstrate that TRAPPC14 interacts with the distal appendage proteins Fas-binding factor 1 (FBF1) and centrosomal protein 83 (CEP83), which we show here are required for GFP-Rabin8 centrosomal accumulation, supporting a role for the TRAPPII complex in tethering preciliary vesicles to the mother centriole during ciliogenesis. In summary, our findings have revealed an uncharacterized TRAPPII-specific component, C7orf43/TRAPPC14, that regulates preciliary trafficking of Rabin8 and ciliogenesis and support previous findings that the TRAPPII complex functions as a membrane tether.
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Affiliation(s)
- Adrian Cuenca
- Center for Cancer Research, NCI-Frederick, National Institutes of Health, Laboratory of Cellular and Developmental Signaling, Frederick, Maryland 21702
| | - Christine Insinna
- Center for Cancer Research, NCI-Frederick, National Institutes of Health, Laboratory of Cellular and Developmental Signaling, Frederick, Maryland 21702
| | - Huijie Zhao
- Center for Cancer Research, NCI-Frederick, National Institutes of Health, Laboratory of Cellular and Developmental Signaling, Frederick, Maryland 21702
| | - Peter John
- Center for Cancer Research, NCI-Frederick, National Institutes of Health, Laboratory of Cellular and Developmental Signaling, Frederick, Maryland 21702
| | - Matthew A Weiss
- Center for Cancer Research, NCI-Frederick, National Institutes of Health, Laboratory of Cellular and Developmental Signaling, Frederick, Maryland 21702
| | - Quanlong Lu
- Center for Cancer Research, NCI-Frederick, National Institutes of Health, Laboratory of Cellular and Developmental Signaling, Frederick, Maryland 21702
| | - Vijay Walia
- Center for Cancer Research, NCI-Frederick, National Institutes of Health, Laboratory of Cellular and Developmental Signaling, Frederick, Maryland 21702
| | - Suzanne Specht
- Center for Cancer Research, NCI-Frederick, National Institutes of Health, Laboratory of Cellular and Developmental Signaling, Frederick, Maryland 21702
| | - Selvambigai Manivannan
- Department of Biomedical Sciences, University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - Jimmy Stauffer
- Center for Cancer Research, NCI-Frederick, National Institutes of Health, Laboratory of Cellular and Developmental Signaling, Frederick, Maryland 21702
| | - Andrew A Peden
- Department of Biomedical Sciences, University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - Christopher J Westlake
- Center for Cancer Research, NCI-Frederick, National Institutes of Health, Laboratory of Cellular and Developmental Signaling, Frederick, Maryland 21702
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15
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Sacher M, Shahrzad N, Kamel H, Milev MP. TRAPPopathies: An emerging set of disorders linked to variations in the genes encoding transport protein particle (TRAPP)-associated proteins. Traffic 2018; 20:5-26. [PMID: 30152084 DOI: 10.1111/tra.12615] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 08/23/2018] [Accepted: 08/26/2018] [Indexed: 02/06/2023]
Abstract
The movement of proteins between cellular compartments requires the orchestrated actions of many factors including Rab family GTPases, Soluble NSF Attachment protein REceptors (SNAREs) and so-called tethering factors. One such tethering factor is called TRAnsport Protein Particle (TRAPP), and in humans, TRAPP proteins are distributed into two related complexes called TRAPP II and III. Although thought to act as a single unit within the complex, in the past few years it has become evident that some TRAPP proteins function independently of the complex. Consistent with this, variations in the genes encoding these proteins result in a spectrum of human diseases with diverse, but partially overlapping, phenotypes. This contrasts with other tethering factors such as COG, where variations in the genes that encode its subunits all result in an identical phenotype. In this review, we present an up-to-date summary of all the known disease-related variations of genes encoding TRAPP-associated proteins and the disorders linked to these variations which we now call TRAPPopathies.
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Affiliation(s)
- Michael Sacher
- Department of Biology, Concordia University, Montreal, Quebec, Canada.,Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, Canada
| | - Nassim Shahrzad
- Department of Medicine, University of California, San Francisco, California
| | - Hiba Kamel
- Department of Biology, Concordia University, Montreal, Quebec, Canada
| | - Miroslav P Milev
- Department of Biology, Concordia University, Montreal, Quebec, Canada
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16
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Dalton LE, Bean BDM, Davey M, Conibear E. Quantitative high-content imaging identifies novel regulators of Neo1 trafficking at endosomes. Mol Biol Cell 2017; 28:1539-1550. [PMID: 28404745 PMCID: PMC5449152 DOI: 10.1091/mbc.e16-11-0772] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Revised: 04/05/2017] [Accepted: 04/06/2017] [Indexed: 12/21/2022] Open
Abstract
P4-ATPases are a family of putative phospholipid flippases that regulate lipid membrane asymmetry, which is important for vesicle formation. Two yeast flippases, Drs2 and Neo1, have nonredundant functions in the recycling of the synaptobrevin-like v-SNARE Snc1 from early endosomes. Drs2 activity is needed to form vesicles and regulate its own trafficking, suggesting that flippase activity and localization are linked. However, the role of Neo1 in endosomal recycling is not well characterized. To identify novel regulators of Neo1 trafficking and activity at endosomes, we first identified mutants with impaired recycling of a Snc1-based reporter and subsequently used high-content microscopy to classify these mutants based on the localization of Neo1 or its binding partners, Mon2 and Dop1. This analysis identified a role for Arl1 in stabilizing the Mon2/Dop1 complex and uncovered a new function for Vps13 in early endosome recycling and Neo1 localization. We further showed that the cargo-selective sorting nexin Snx3 is required for Neo1 trafficking and identified an Snx3 sorting motif in the Neo1 N-terminus. Of importance, the Snx3-dependent sorting of Neo1 was required for the correct sorting of another Snx3 cargo protein, suggesting that the incorporation of Neo1 into recycling tubules may influence their formation.
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Affiliation(s)
- Lauren E Dalton
- Centre for Molecular Medicine and Therapeutics, BC Children's Hospital, University of British Columbia, Vancouver, BC V5Z 4H4, Canada
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Björn D M Bean
- Centre for Molecular Medicine and Therapeutics, BC Children's Hospital, University of British Columbia, Vancouver, BC V5Z 4H4, Canada
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Michael Davey
- Centre for Molecular Medicine and Therapeutics, BC Children's Hospital, University of British Columbia, Vancouver, BC V5Z 4H4, Canada
| | - Elizabeth Conibear
- Centre for Molecular Medicine and Therapeutics, BC Children's Hospital, University of British Columbia, Vancouver, BC V5Z 4H4, Canada
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
- Department of Medical Genetics, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
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17
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Zhao S, Li CM, Luo XM, Siu GKY, Gan WJ, Zhang L, Wu WKK, Chan HC, Yu S. Mammalian TRAPPIII Complex positively modulates the recruitment of Sec13/31 onto COPII vesicles. Sci Rep 2017; 7:43207. [PMID: 28240221 PMCID: PMC5327430 DOI: 10.1038/srep43207] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Accepted: 01/23/2017] [Indexed: 11/09/2022] Open
Abstract
The Transport protein particle (TRAPP) complex is a tethering factor for COPII vesicle. Of three forms of TRAPP (TRAPPI, II and III) complexes identified so far, TRAPPIII has been largely considered to play a role in autophagy. While depletion of TRAPPIII specific subunits caused defects in the early secretory pathway and TRAPPIII might interact with components of the COPII vesicle coat, its exact role remains to be determined. In this study, we studied the function of TRAPPIII in early secretory pathway using a TRAPPIII-specific subunit, TRAPPC12, as starting point. We found that TRAPPC12 was localized to the ER exit sites and ERGIC. In cells deleted with TRAPPC12, ERGIC and to a lesser extent, the Golgi became dispersed. ER-to-Golgi transport was also delayed. TRAPPC12, but not TRAPPC8, bound to Sec13/Sec31A tetramer but each Sec protein alone could not interact with TRAPPC12. TRAPPIII positively modulated the assembly of COPII outer layer during COPII vesicle formation. These results identified a novel function of TRAPPIII as a positive modulator of the outer layer of the COPII coat.
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Affiliation(s)
- Shan Zhao
- School of Biomedical Sciences, The Chinese University of Hong Kong, Sha Tin, N.T., Hong Kong SAR, P.R. China
| | - Chun Man Li
- School of Biomedical Sciences, The Chinese University of Hong Kong, Sha Tin, N.T., Hong Kong SAR, P.R. China
| | - Xiao Min Luo
- School of Biomedical Sciences, The Chinese University of Hong Kong, Sha Tin, N.T., Hong Kong SAR, P.R. China
| | - Gavin Ka Yu Siu
- School of Biomedical Sciences, The Chinese University of Hong Kong, Sha Tin, N.T., Hong Kong SAR, P.R. China
| | - Wen Jia Gan
- School of Biomedical Sciences, The Chinese University of Hong Kong, Sha Tin, N.T., Hong Kong SAR, P.R. China
| | - Lin Zhang
- School of Biomedical Sciences, The Chinese University of Hong Kong, Sha Tin, N.T., Hong Kong SAR, P.R. China.,Department of anesthesia, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, P.R. China
| | - William K K Wu
- Department of anesthesia, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, P.R. China
| | - Hsiao Chang Chan
- School of Biomedical Sciences, The Chinese University of Hong Kong, Sha Tin, N.T., Hong Kong SAR, P.R. China.,Epithelial Cell Biology Research Centre, The Chinese University of Hong Kong, Sha Tin, N.T., Hong Kong SAR, P.R. China
| | - Sidney Yu
- School of Biomedical Sciences, The Chinese University of Hong Kong, Sha Tin, N.T., Hong Kong SAR, P.R. China.,Epithelial Cell Biology Research Centre, The Chinese University of Hong Kong, Sha Tin, N.T., Hong Kong SAR, P.R. China
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18
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Li C, Luo X, Zhao S, Siu GK, Liang Y, Chan HC, Satoh A, Yu SS. COPI-TRAPPII activates Rab18 and regulates its lipid droplet association. EMBO J 2016; 36:441-457. [PMID: 28003315 DOI: 10.15252/embj.201694866] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Revised: 11/11/2016] [Accepted: 11/16/2016] [Indexed: 11/09/2022] Open
Abstract
The transport protein particle (TRAPP) was initially identified as a vesicle tethering factor in yeast and as a guanine nucleotide exchange factor (GEF) for Ypt1/Rab1. In mammals, structures and functions of various TRAPP complexes are beginning to be understood. We found that mammalian TRAPPII was a GEF for both Rab18 and Rab1. Inactivation of TRAPPII-specific subunits by various methods including siRNA depletion and CRISPR-Cas9-mediated deletion reduced lipolysis and resulted in aberrantly large lipid droplets. Recruitment of Rab18 onto lipid droplet (LD) surface was defective in TRAPPII-deleted cells, but the localization of Rab1 on Golgi was not affected. COPI regulates LD homeostasis. We found that the previously documented interaction between TRAPPII and COPI was also required for the recruitment of Rab18 to the LD We hypothesize that the interaction between COPI and TRAPPII helps bring TRAPPII onto LD surface, and TRAPPII, in turn, activates Rab18 and recruits it on the LD surface to facilitate its functions in LD homeostasis.
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Affiliation(s)
- Chunman Li
- Department of Anatomy, Histology and Developmental Biology, School of Basic Medical Sciences, Health Science Centre, Shenzhen University, Shenzhen, China.,School of Biomedical Sciences, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China
| | - Xiaomin Luo
- School of Biomedical Sciences, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China
| | - Shan Zhao
- School of Biomedical Sciences, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China
| | - Gavin Ky Siu
- School of Biomedical Sciences, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China
| | - Yongheng Liang
- Key Laboratory of Agricultural Environmental Microbiology of MOA, College of Life Sciences, Nanjing Agricultural University, Nanjing, China
| | - Hsiao Chang Chan
- School of Biomedical Sciences, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China.,Epithelial Cell Biology Research Centre, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China
| | - Ayano Satoh
- The Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan
| | - Sidney Sb Yu
- School of Biomedical Sciences, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China .,Epithelial Cell Biology Research Centre, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China
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19
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Host Cellular Protein TRAPPC6AΔ Interacts with Influenza A Virus M2 Protein and Regulates Viral Propagation by Modulating M2 Trafficking. J Virol 2016; 91:JVI.01757-16. [PMID: 27795429 PMCID: PMC5165196 DOI: 10.1128/jvi.01757-16] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 09/30/2016] [Indexed: 12/30/2022] Open
Abstract
Influenza A virus (IAV) matrix protein 2 (M2) plays multiple roles in the early and late phases of viral infection. Once synthesized, M2 is translocated to the endoplasmic reticulum (ER), travels to the Golgi apparatus, and is sorted at the trans-Golgi network (TGN) for transport to the apical plasma membrane, where it functions in virus budding. We hypothesized that M2 trafficking along with its secretory pathway must be finely regulated, and host factors could be involved in this process. However, no studies examining the role of host factors in M2 posttranslational transport have been reported. Here, we used a yeast two-hybrid (Y2H) system to screen for host proteins that interact with the M2 protein and identified transport protein particle complex 6A (TRAPPC6A) as a potential binding partner. We found that both TRAPPC6A and its N-terminal internal-deletion isoform, TRAPPC6A delta (TRAPPC6AΔ), interact with M2. Truncation and mutation analyses showed that the highly conserved leucine residue at position 96 of M2 is critical for mediating this interaction. The role of TRAPPC6AΔ in the viral life cycle was investigated by the knockdown of endogenous TRAPPC6AΔ with small interfering RNA (siRNA) and by generating a recombinant virus that was unable to interact with TRAPPC6A/TRAPPC6AΔ. The results indicated that TRAPPC6AΔ, through its interaction with M2, slows M2 trafficking to the apical plasma membrane, favors viral replication in vitro, and positively modulates virus virulence in mice. IMPORTANCE The influenza A virus M2 protein regulates the trafficking of not only other proteins but also itself along the secretory pathway. However, the host factors involved in the regulation of the posttranslational transport of M2 are largely unknown. In this study, we identified TRAPPC6A and its N-terminal internal-deletion isoform, TRAPPC6AΔ, as interacting partners of M2. We found that the leucine (L) residue at position 96 of M2 is critical for mediating this interaction, which leads us to propose that the high level of conservation of 96L is a consequence of M2 adaptation to its interacting host factor TRAPPC6A/TRAPPC6AΔ. Importantly, we discovered that TRAPPC6AΔ can positively regulate viral replication in vitro by modulating M2 trafficking to the plasma membrane.
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20
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Trs33-Containing TRAPP IV: A Novel Autophagy-Specific Ypt1 GEF. Genetics 2016; 204:1117-1128. [PMID: 27672095 DOI: 10.1534/genetics.116.194910] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Accepted: 09/18/2016] [Indexed: 11/18/2022] Open
Abstract
Ypt/Rab GTPases, key regulators of intracellular trafficking pathways, are activated by guanine-nucleotide exchange factors (GEFs). Here, we identify a novel GEF complex, TRAPP IV, which regulates Ypt1-mediated autophagy. In the yeast Saccharomyces cerevisiae, Ypt1 GTPase is required for the initiation of secretion and autophagy, suggesting that it regulates these two distinct pathways. However, whether these pathways are coordinated by Ypt1 and by what mechanism is still unknown. TRAPP is a conserved modular complex that acts as a Ypt/Rab GEF. Two different TRAPP complexes, TRAPP I and the Trs85-containing TRAPP III, activate Ypt1 in the secretory and autophagic pathways, respectively. Importantly, whereas TRAPP I depletion copies Ypt1 deficiency in secretion, depletion of TRAPP III does not fully copy the autophagy phenotypes of autophagy-specific ypt1 mutations. If GEFs are required for Ypt/Rab function, this discrepancy implies the existence of an additional GEF that activates Ypt1 in autophagy. Trs33, a nonessential TRAPP subunit, was assigned to TRAPP I without functional evidence. We show that in the absence of Trs85, Trs33 is required for Ypt1-mediated autophagy and for the recruitment of core-TRAPP and Ypt1 to the preautophagosomal structure, which marks the onset of autophagy. In addition, Trs33 and Trs85 assemble into distinct TRAPP complexes, and we term the Trs33-containing autophagy-specific complex TRAPP IV. Because TRAPP I is required for Ypt1-mediated secretion, and either TRAPP III or TRAPP IV is required for Ypt1-mediated autophagy, we propose that pathway-specific GEFs activate Ypt1 in secretion and autophagy.
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21
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Brunet S, Saint-Dic D, Milev MP, Nilsson T, Sacher M. The TRAPP Subunit Trs130p Interacts with the GAP Gyp6p to Mediate Ypt6p Dynamics at the Late Golgi. Front Cell Dev Biol 2016; 4:48. [PMID: 27252941 PMCID: PMC4877375 DOI: 10.3389/fcell.2016.00048] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 05/09/2016] [Indexed: 01/05/2023] Open
Abstract
Small GTPases of the Rab superfamily participate in virtually all vesicle-mediated trafficking events. Cycling between an active GTP-bound form and an inactive GDP-bound form is accomplished in conjunction with guanine nucleotide exchange factors (GEFs) and GTPase activating proteins (GAPs), respectively. Rab cascades have been described in which an effector of an activated Rab is a GEF for a downstream Rab, thus ensuring activation of a pathway in an ordered fashion. Much less is known concerning crosstalk between GEFs and GAPs although regulation between these factors could also contribute to the overall physiology of a cell. Here we demonstrate that a subunit of the TRAPP II multisubunit tethering factor, a Rab GEF, participates in the recruitment of Gyp6p, a GAP for the GTPase Ypt6p, to Golgi membranes. The extreme carboxy-terminal portion of the TRAPP II subunit Trs130p is required for the interaction between TRAPP II and Gyp6p. We further demonstrate that TRAPP II mutants, but not a TRAPP III mutant, display a defect in Gyp6p interaction. A consequence of this defective interaction is the enhanced localization of Ypt6p at late Golgi membranes. Although a ypt31/32 mutant also resulted in an enhanced localization of Gyp6p at the late Golgi, the effect was not as dramatic as that seen for TRAPP II mutants, nor was Ypt31/32 detected in the same TRAPP II purification that detected Gyp6p. We propose that the interaction between TRAPP II and Gyp6p represents a parallel mechanism in addition to that mediated by Ypt31/32 for the recruitment of a GAP to the appropriate membrane, and is a novel example of crosstalk between a Rab GAP and GEF.
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Affiliation(s)
- Stephanie Brunet
- Department of Biology, Concordia University Montreal, QC, Canada
| | | | - Miroslav P Milev
- Department of Biology, Concordia University Montreal, QC, Canada
| | - Tommy Nilsson
- Department of Medicine, McGill University Montreal, QC, Canada
| | - Michael Sacher
- Department of Biology, Concordia UniversityMontreal, QC, Canada; Department of Anatomy and Cell Biology, McGill UniversityMontreal, QC, Canada
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22
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Kim JJ, Lipatova Z, Segev N. TRAPP Complexes in Secretion and Autophagy. Front Cell Dev Biol 2016; 4:20. [PMID: 27066478 PMCID: PMC4811894 DOI: 10.3389/fcell.2016.00020] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Accepted: 03/04/2016] [Indexed: 12/13/2022] Open
Abstract
TRAPP is a highly conserved modular multi-subunit protein complex. Originally identified as a “transport protein particle” with a role in endoplasmic reticulum-to-Golgi transport, its multiple subunits and their conservation from yeast to humans were characterized in the late 1990s. TRAPP attracted attention when it was shown to act as a Ypt/Rab GTPase nucleotide exchanger, GEF, in the 2000s. Currently, three TRAPP complexes are known in yeast, I, II, and III, and they regulate two different intracellular trafficking pathways: secretion and autophagy. Core TRAPP contains four small subunits that self assemble to a stable complex, which has a GEF activity on Ypt1. Another small subunit, Trs20/Sedlin, is an adaptor required for the association of core TRAPP with larger subunits to form TRAPP II and TRAPP III. Whereas the molecular structure of the core TRAPP complex is resolved, the architecture of the larger TRAPP complexes, including their existence as dimers and multimers, is less clear. In addition to its Ypt/Rab GEF activity, and thereby an indirect role in vesicle tethering through Ypt/Rabs, a direct role for TRAPP as a vesicle tether has been suggested. This idea is based on TRAPP interactions with vesicle coat components. While much of the basic information about TRAPP complexes comes from yeast, mutations in TRAPP subunits were connected to human disease. In this review we will summarize new information about TRAPP complexes, highlight new insights about their function and discuss current controversies and future perspectives.
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Affiliation(s)
- Jane J Kim
- Department of Biological Sciences, University of Illinois at Chicago Chicago, IL, USA
| | - Zhanna Lipatova
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago Chicago, IL, USA
| | - Nava Segev
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago Chicago, IL, USA
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23
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TRAPPII regulates exocytic Golgi exit by mediating nucleotide exchange on the Ypt31 ortholog RabERAB11. Proc Natl Acad Sci U S A 2015; 112:4346-51. [PMID: 25831508 DOI: 10.1073/pnas.1419168112] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The oligomeric complex transport protein particle I (TRAPPI) mediates nucleotide exchange on the RAB GTPase RAB1/Ypt1. TRAPPII is composed of TRAPPI plus three additional subunits, Trs120, Trs130, and Trs65. Unclear is whether TRAPPII mediates nucleotide exchange on RAB1/Ypt1, RAB11/Ypt31, or both. In Aspergillus nidulans, RabO(RAB1) resides in the Golgi, RabE(RAB11) localizes to exocytic post-Golgi carriers undergoing transport to the apex, and hypA encodes Trs120. RabE(RAB11), but not RabO(RAB1), immunoprecipitates contain Trs120/Trs130/Trs65, demonstrating specific association of TRAPPII with RabE(RAB11) in vivo. hypA1(ts) rapidly shifts RabE(RAB11), but not RabO(RAB1), to the cytosol, consistent with HypA(Trs120) being specifically required for RabE(RAB11) activation. Missense mutations rescuing hypA1(ts) at 42 °C mapped to rabE, affecting seven residues. Substitutions in six, of which four resulted in 7- to 36-fold accelerated GDP release, rescued lethality associated to TRAPPII deficiency, whereas equivalent substitutions in RabO(RAB1) did not, establishing that the essential role of TRAPPII is facilitating RabE(RAB11) nucleotide exchange. In vitro, TRAPPII purified with HypA(Trs120)-S-tag accelerates nucleotide exchange on RabE(RAB11) and, paradoxically, to a lesser yet substantial extent, on RabO(RAB1). Evidence obtained by exploiting hypA1-mediated destabilization of HypA(Trs120)/HypC(Trs130)/Trs65 assembly onto the TRAPPI core indicates that these subunits sculpt a second RAB binding site on TRAPP apparently independent from that for RabO(RAB1), which would explain TRAPPII in vitro activity on two RABs. Using A. nidulans in vivo microscopy, we show that HypA(Trs120) colocalizes with RabE(RAB11), arriving at late Golgi cisternae as they dissipate into exocytic carriers. Thus, TRAPPII marks, and possibly determines, the Golgi-to-post-Golgi transition.
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24
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Lipatova Z, Hain AU, Nazarko VY, Segev N. Ypt/Rab GTPases: principles learned from yeast. Crit Rev Biochem Mol Biol 2015; 50:203-11. [PMID: 25702751 DOI: 10.3109/10409238.2015.1014023] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Ypt/Rab GTPases are key regulators of all membrane trafficking events in eukaryotic cells. They act as molecular switches that attach to membranes via lipid tails to recruit their multiple downstream effectors, which mediate vesicular transport. Originally discovered in yeast as Ypts, they were later shown to be conserved from yeast to humans, where Rabs are relevant to a wide array of diseases. Major principles learned from our past studies in yeast are currently accepted in the Ypt/Rab field including: (i) Ypt/Rabs are not transport-step specific, but are rather compartment specific, (ii) stimulation by nucleotide exchangers, GEFs, is critical to their function, whereas GTP hydrolysis plays a role in their cycling between membranes and the cytoplasm for multiple rounds of action, (iii) they mediate diverse functions ranging from vesicle formation to vesicle fusion and (iv) they act in GTPase cascades to regulate intracellular trafficking pathways. Our recent studies on Ypt1 and Ypt31/Ypt32 and their modular GEF complex TRAPP raise three exciting novel paradigms for Ypt/Rab function: (a) coordination of vesicular transport substeps, (b) integration of individual transport steps into pathways and (c) coordination of different transport pathways. In addition to its amenability to genetic analysis, yeast provides a superior model system for future studies on the role of Ypt/Rabs in traffic coordination due to the smaller proteome that results in a simpler traffic grid. We propose that different types of coordination are important also in human cells for fine-tuning of intracellular trafficking, and that coordination defects could result in disease.
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Affiliation(s)
- Zhanna Lipatova
- a Department of Biochemistry and Molecular Genetics , University of Illinois at Chicago , Chicago , IL , USA
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25
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Zou S, Liu Y, Zhang C, Yu S, Liang Y. Bet3 participates in autophagy through GTPase Ypt1 in Saccharomyces cerevisiae. Cell Biol Int 2015; 39:466-74. [PMID: 25581738 DOI: 10.1002/cbin.10416] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Accepted: 12/13/2014] [Indexed: 11/08/2022]
Abstract
Three TRAPP (transport protein particle) complexes have been identified in Saccharomyces cerevisiae. GTPases Ypt1 and Ypt31/32 suppress autophagic defects in the mutants of TRAPPIII-specific subunit (Trs85) and TRAPPII-specific subunits (Trs130 and Trs120), respectively. However, the roles of the common TRAPP subunits (which also form the TRAPPI complex) in autophagy and their relationship to Rab GTPases in autophagy remain unclear. As Bet3 (a common TRAPP subunit) cannot be mutated together with either Trs85 or Trs130, we examined starvation-induced autophagy and the cytoplasm-to-vacuole targeting (Cvt) pathway in bet3ts cells. The results demonstrated that GFP-Atg8 was dispersed in the cytoplasm and Ape1 accumulated as a unique dot on the vacuolar membrane in bet3ts cells. Further analysis revealed that Ape1 maturation and GFP-Atg8 processing are defective in these cells. However, prApe1 (precursor form of Ape1) and GFP-Atg8 are protease-accessible in bet3ts cells under starvation, which indicates that Bet3 functions before autophagosome closure. Furthermore, active Ypt1, but not Ypt31, partly rescued the autophagic defects of bet3ts cells. We conclude that Bet3 is involved in autophagy and propose that it participates in autophagy through TRAPP complexes mostly via Ypt1 in yeast.
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Affiliation(s)
- Shenshen Zou
- Key Laboratory of Agricultural Environmental Microbiology of Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, China
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26
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Brunet S, Sacher M. Are all multisubunit tethering complexes bona fide tethers? Traffic 2014; 15:1282-7. [PMID: 25048641 DOI: 10.1111/tra.12200] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Revised: 07/18/2014] [Accepted: 07/18/2014] [Indexed: 01/15/2023]
Abstract
Since the late 1990s, a number of multisubunit tethering complexes (MTCs) have been described that function in membrane trafficking events: TRAPP I, TRAPP II, TRAPP III, COG, HOPS, CORVET, Dsl1, GARP and exocyst. On the basis of structural and sequence similarities, they have been categorized as complexes associated with tethering containing helical rods (CATCHR) (Dsl1, COG, GARP and exocyst) or non-CATCHR (TRAPP I, II and III, HOPS and CORVET) complexes (Yu IM, Hughson FM. Tethering factors as organizers of intracellular vesicular traffic. Annu Rev Cell Dev Biol 2010;26:137-156). Both acronyms (CATCHR and MTC) imply these complexes tether opposing membranes to facilitate fusion. The main question we will address is: have these complexes been formally demonstrated to function as tethers? If the answer is no, then is it premature or even correct to refer to them as tethers? In this commentary, we will argue that the vast majority of MTCs have not been demonstrated to act as a tether. We propose that a distinction between the terms tether and tethering factor be considered to address this issue.
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Affiliation(s)
- Stephanie Brunet
- Department of Biology, Concordia University, Montreal, Quebec, Canada
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27
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Taussig D, Lipatova Z, Segev N. Trs20 is required for TRAPP III complex assembly at the PAS and its function in autophagy. Traffic 2014; 15:327-37. [PMID: 24329977 DOI: 10.1111/tra.12145] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2013] [Revised: 12/06/2013] [Accepted: 12/10/2013] [Indexed: 02/03/2023]
Abstract
The modular TRAPP complex acts as a guanine-nucleotide exchange factor (GEF) for Ypt/Rab GTPases. Whereas TRAPP I and TRAPP II regulate the exocytic pathway, TRAPP III functions in autophagy. The TRAPP subunit Trs20 is not required for assembly of core TRAPP or its Ypt1 GEF activity. Interestingly, mutations in the human functional ortholog of Trs20, Sedlin, cause spondyloepiphyseal dysplasia tarda (SEDT), a cartilage-specific disorder. We have shown that Trs20 is required for TRAPP II assembly and identified a SEDT-linked mutation, Trs20-D46Y, which causes a defect in this process. Here we show that Trs20 is also required for assembly of TRAPP III at the pre-autophagosomal structure (PAS). First, recombinant Trs85, a TRAPP III-specific subunit, associates with TRAPP only in the presence of Trs20, but not Trs20-D46Y mutant protein. Second, a TRAPP complex with Ypt1 GEF activity co-precipitates with Trs85 from wild type, but not trs20ts mutant, cell lysates. Third, live-cell colocalization analysis indicates that Trs85 recruits core TRAPP to the PAS via the linker protein Trs20. Finally, trs20ts mutant cells are defective in selective and non-selective autophagy. Together, our results show that Trs20 plays a role as an adaptor in the assembly of TRAPP II and TRAPP III complexes, and the SEDT-linked mutation causes a defect in both processes.
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Affiliation(s)
- David Taussig
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, 900 South Ashland Avenue, Chicago, IL, 60612, USA
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Weng L, Piotrowski A, Morrison DA. Exit from competence for genetic transformation in Streptococcus pneumoniae is regulated at multiple levels. PLoS One 2013; 8:e64197. [PMID: 23717566 PMCID: PMC3661451 DOI: 10.1371/journal.pone.0064197] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Accepted: 04/12/2013] [Indexed: 12/25/2022] Open
Abstract
Development of natural competence in S. pneumoniae entails coordinated expression of two sets of genes. Early gene expression depends on ComE, a response regulator activated by the pheromone CSP (Competence-Stimulating-Peptide). Subsequently, an early gene product (the alternative sigma factor ComX) activates expression of late genes, establishing the competent state. Expression of both sets of genes is transient, rapidly shut off by a mechanism that depends on the late gene, dprA. It has been thought that the rapid shutoff of late gene expression is the combined result of auto-inhibition of ComE and the instability of ComX. However, this explanation seems incomplete, because of evidence for ComX-dependent repressor(s) that might also be important for shutting off the response to CSP and identifying dprA as such a gene. We screened individual late gene mutants to investigate further the roles of ComX-dependent genes in competence termination. A ΔdprA mutant displayed a prolonged late gene expression pattern, whereas mutants lacking cbpD, cibABC, cglEFG, coiA, ssbB, celAB, cclA, cglABCD, cflAB, or radA, exhibited a wild-type temporal expression pattern. Thus, no other gene than dprA was found to be involved in shutoff. DprA limits the amounts of ComX and another early gene product, ComW, by restriction of early gene expression rather than by promoting proteolysis. To ask if DprA also affects late gene expression, we decoupled late gene expression from early gene regulation. Because DprA did not limit ComX activity under these conditions, we also conclude that ComX activity is limited by another mechanism not involving DprA.
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Affiliation(s)
- Liming Weng
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Andrew Piotrowski
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Donald A. Morrison
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois, United States of America
- * E-mail:
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Taussig D, Lipatova Z, Kim JJ, Zhang X, Segev N. Trs20 is required for TRAPP II assembly. Traffic 2013; 14:678-90. [PMID: 23465091 DOI: 10.1111/tra.12065] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Revised: 02/22/2013] [Accepted: 03/07/2013] [Indexed: 11/28/2022]
Abstract
The modular TRAPP complexes act as nucleotide exchangers to activate the Golgi Ypt/Rab GTPases, Ypt1 and Ypt31/Ypt32. In yeast, TRAPP I acts at the cis-Golgi and its assembly and structure are well characterized. In contrast, TRAPP II acts at the trans-Golgi and is poorly understood. Especially puzzling is the role of Trs20, an essential TRAPP I/II subunit required neither for the assembly of TRAPP I nor for its Ypt1-exchange activity. Mutations in Sedlin, the human functional ortholog of Trs20, cause the cartilage-specific disorder SEDT. Here we show that Trs20 interacts with the TRAPP II-specific subunit Trs120. Furthermore, the Trs20-Trs120 interaction is required for assembly of TRAPP II and for its Ypt32-exchange activity. Finally, Trs20-D46Y, with a single-residue substitution equivalent to a SEDT-causing mutation in Sedlin, interacts with TRAPP I, but the resulting TRAPP complex cannot interact with Trs120 and TRAPP II cannot be assembled. These results indicate that Trs20 is crucial for assembly of TRAPP II, and the defective assembly caused by a SEDT-linked mutation suggests that this role is conserved.
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Affiliation(s)
- David Taussig
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL, USA
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Yu S, Liang Y. A trapper keeper for TRAPP, its structures and functions. Cell Mol Life Sci 2012; 69:3933-44. [PMID: 22669257 PMCID: PMC11114727 DOI: 10.1007/s00018-012-1024-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2012] [Revised: 04/20/2012] [Accepted: 05/02/2012] [Indexed: 12/22/2022]
Abstract
During biosynthesis many membrane and secreted proteins are transported from the endoplasmic reticulum, through the Golgi and on to the plasma membrane in small transport vesicles. These transport vesicles have to undergo budding, movement, tethering, docking, and fusion at each organelle of the biosynthetic pathway. The transport protein particle (TRAPP) complex was initially identified as the tethering factor for endoplasmic reticulum (ER)-derived COPII vesicles, but the functions of TRAPP may extend to other areas of biology. Three forms of TRAPP complexes have been discovered to date, and recent advances in research have provided new insights on the structures and functions of TRAPP. Here we provide a comprehensive review of the recent findings in TRAPP biology.
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Affiliation(s)
- Sidney Yu
- School of Biomedical Sciences and Epithelial Cell Biology Research Center, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, People's Republic of China,
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Zou S, Chen Y, Liu Y, Segev N, Yu S, Liu Y, Min G, Ye M, Zeng Y, Zhu X, Hong B, Björn LO, Liang Y, Li S, Xie Z. Trs130 participates in autophagy through GTPases Ypt31/32 in Saccharomyces cerevisiae. Traffic 2012; 14:233-46. [PMID: 23078654 DOI: 10.1111/tra.12024] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2012] [Revised: 10/16/2012] [Accepted: 10/19/2012] [Indexed: 02/03/2023]
Abstract
Trs130 is a specific component of the transport protein particle II complex, which functions as a guanine nucleotide exchange factor (GEF) for Rab GTPases Ypt31/32. Ypt31/32 is known to be involved in autophagy, although the precise mechanism has not been thoroughly studied. In this study, we investigated the potential involvement of Trs130 in autophagy and found that both the cytoplasm-to-vacuole targeting (Cvt) pathway and starvation-induced autophagy were defective in a trs130ts (trs130 temperature-sensitive) mutant. Mutant cells could not transport Atg8 and Atg9 to the pre-autophagosomal structure/phagophore assembly site (PAS) properly, resulting in multiple Atg8 dots and Atg9 dots dispersed in the cytoplasm. Some dots were trapped in the trans-Golgi. Genetic studies showed that the effect of the Trs130 mutation was downstream of Atg5 and upstream of Atg1, Atg13, Atg9 and Atg14 on the autophagic pathway. Furthermore, overexpression of Ypt31 or Ypt32, but not of Ypt1, rescued autophagy defects in trs130ts and trs65ts (Trs130-HA Trs120-myc trs65Δ) mutants. Our data provide mechanistic insight into how Trs130 participates in autophagy and suggest that vesicular trafficking regulated by GTPases/GEFs is important in the transport of autophagy proteins from the trans-Golgi to the PAS.
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Affiliation(s)
- Shenshen Zou
- College of Life Sciences, Key Laboratory of Agricultural Environmental Microbiology of Ministry of Agriculture, Nanjing Agricultural University, Nanjing, 210095, China
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Modular TRAPP complexes regulate intracellular protein trafficking through multiple Ypt/Rab GTPases in Saccharomyces cerevisiae. Genetics 2012; 191:451-60. [PMID: 22426882 DOI: 10.1534/genetics.112.139378] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Ypt/Rab are key regulators of intracellular trafficking in all eukaryotic cells. In yeast, Ypt1 is essential for endoplasmic reticulum (ER)-to-Golgi transport, whereas Ypt31/32 regulate Golgi-to-plasma membrane and endosome-to-Golgi transport. TRAPP is a multisubunit complex that acts as an activator of Ypt/Rab GTPases. Trs85 and Trs130 are two subunits specific for TRAPP III and TRAPP II, respectively. Whereas TRAPP III was shown to acts as a Ypt1 activator, it is still controversial whether TRAPP II acts as a Ypt1 or Ypt31/32 activator. Here, we use GFP-Snc1 as a tool to study transport in Ypt and TRAPP mutant cells. First, we show that expression of GFP-Snc1 in trs85Δ mutant cells results in temperature sensitivity. Second, we suggest that in ypt1ts and trs85Δ, but not in ypt31Δ/32ts and trs130ts mutant cells, GFP-Snc1 accumulates in the ER. Third, we show that overexpression of Ypt1, but not Ypt31/32, can suppress both the growth and GFP-Snc1 accumulation phenotypes of trs85Δ mutant cells. In contrast, overexpression of Ypt31, but not Ypt1, suppresses the growth and GFP-Snc1 transport phenotypes of trs130ts mutant cells. These results provide genetic support for functional grouping of Ypt1 with Trs85-containing TRAPP III and Ypt31/32 with Trs130-containing TRAPP II.
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Chen S, Cai H, Park SK, Menon S, Jackson CL, Ferro-Novick S. Trs65p, a subunit of the Ypt1p GEF TRAPPII, interacts with the Arf1p exchange factor Gea2p to facilitate COPI-mediated vesicle traffic. Mol Biol Cell 2011; 22:3634-44. [PMID: 21813735 PMCID: PMC3183018 DOI: 10.1091/mbc.e11-03-0197] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The TRAPPII-specific subunit Trs65p directly binds to the C-terminus of the Arf1p exchange factor Gea2p. In addition, Gea2p and TRAPPII bind to the yeast orthologue of the γ subunit of the COPI coat complex, a known Arf1p effector. Thus TRAPPII is part of an Arf1p GEF-effector loop that appears to play a role in recruiting or stabilizing TRAPPII to membranes. The TRAPP complexes are multimeric guanine exchange factors (GEFs) for the Rab GTPase Ypt1p. The three complexes (TRAPPI, TRAPPII, and TRAPPIII) share a core of common subunits required for GEF activity, as well as unique subunits (Trs130p, Trs120p, Trs85p, and Trs65p) that redirect the GEF from the endoplasmic reticulum–Golgi pathway to different cellular locations where TRAPP mediates distinct membrane trafficking events. Roles for three of the four unique TRAPP subunits have been described before; however, the role of the TRAPPII-specific subunit Trs65p has remained elusive. Here we demonstrate that Trs65p directly binds to the C-terminus of the Arf1p exchange factor Gea2p and provide in vivo evidence that this interaction is physiologically relevant. Gea2p and TRAPPII also bind to the yeast orthologue of the γ subunit of the COPI coat complex (Sec21p), a known Arf1p effector. These and previous findings reveal that TRAPPII is part of an Arf1p GEF-effector loop that appears to play a role in recruiting or stabilizing TRAPPII to membranes. In support of this proposal, we show that TRAPPII is more soluble in an arf1Δ mutant.
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Affiliation(s)
- Shuliang Chen
- Department of Cellular and Molecular Medicine, Howard Hughes Medical Institute, University of California at San Diego, La Jolla, CA 92093-0668, USA
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Choi C, Davey M, Schluter C, Pandher P, Fang Y, Foster LJ, Conibear E. Organization and Assembly of the TRAPPII Complex. Traffic 2011; 12:715-25. [DOI: 10.1111/j.1600-0854.2011.01181.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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