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Zheng M, Kong X, Jiang X, Yang Y, Fu S, Wen C, Zhang W, Di W. Qualitative analysis of Fasciola gigantica excretory and secretory products coimmunoprecipitated with buffalo secondary infection sera shows dissimilar components from primary infection sera. Acta Trop 2024; 260:107391. [PMID: 39278520 DOI: 10.1016/j.actatropica.2024.107391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2024] [Revised: 08/30/2024] [Accepted: 09/07/2024] [Indexed: 09/18/2024]
Abstract
Buffaloes cannot mount a robust adaptive immune response to secondary infection by Fasciola gigantica. Even if excretory and secretory products (ESPs) exhibit potent immunoregulatory effects during primary infection, research on ESPs in secondary infection is lacking, even though the ESP components that are excreted/secreted during secondary infection are unknown. Therefore, qualitative analysis of ESP during secondary infection was performed and compared with that of primary infection to deepen the recognition of secondary infection and facilitate immunoregulatory molecules screening. Buffaloes were divided into three groups: A (n = 3, noninfected), B (n = 3, primary infection) and C (n = 3, secondary infection). Buffaloes in the primary (0 weeks post infection; wpi) and secondary (-4 and 0 wpi) infection groups were infected with 250 metacercariae by oral administration. Then, sera were collected from groups at different wpi, and interacting proteins were precipitated by coimmunoprecipitation (Co-IP), qualitatively analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS), and annotated by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses to infer their potential functions. In group C, 324 proteins were identified, of which 76 proteins were consistently identified across 7 time points (1, 3, 6, 8, 10, 13, and 16 wpi). Compared with 87 proteins consistently identified in group B, 22 proteins were identified in group C. Meanwhile, 34 proteins were only identified in group C compared to 200 proteins identified in group B. Protein pathway analysis indicated that these proteins were mainly involved in the cellular processes and metabolism of F. gigantica. Among them, 14-3-3θ was consistently identified in group C and may be involved in various cellular processes and innate immune signalling pathways. Members of the HSP family were identified in both groups B and C and may function in both primary and secondary infection processes. The proteins discovered in the present study will help to deepen the understanding of the molecular interactions between F. gigantica and buffalo during secondary infection and facilitate the identification of new potential immunoregulatory molecules.
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Affiliation(s)
- Mengwei Zheng
- College of Animal Science and Technology, Guangxi University, Nanning, 530005, PR China
| | - Xinping Kong
- College of Animal Science and Technology, Guangxi University, Nanning, 530005, PR China
| | - Xuelian Jiang
- College of Animal Science and Technology, Guangxi University, Nanning, 530005, PR China
| | - Yankun Yang
- College of Animal Science and Technology, Guangxi University, Nanning, 530005, PR China
| | - Shishi Fu
- College of Animal Science and Technology, Guangxi University, Nanning, 530005, PR China
| | - Chongli Wen
- Guangxi Buffalo Research Institute, Chinese Academy Agricultural Sciences, Nanning, 530001, PR China.
| | - Weiyu Zhang
- College of Animal Science and Technology, Guangxi University, Nanning, 530005, PR China.
| | - Wenda Di
- College of Animal Science and Technology, Guangxi University, Nanning, 530005, PR China.
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2
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Malis Y, Armoza-Eilat S, Nevo-Yassaf I, Dukhovny A, Sklan EH, Hirschberg K. Rab1b facilitates lipid droplet growth by ER-to-lipid droplet targeting of DGAT2. SCIENCE ADVANCES 2024; 10:eade7753. [PMID: 38809969 PMCID: PMC11135398 DOI: 10.1126/sciadv.ade7753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2023] [Accepted: 04/16/2024] [Indexed: 05/31/2024]
Abstract
Lipid droplets (LDs) comprise a triglyceride core surrounded by a lipid monolayer enriched with proteins, many of which function in LD homeostasis. How proteins are targeted to the growing LD is still unclear. Rab1b, a GTPase regulating secretory transport, was recently associated with targeting proteins to LDs in a Drosophila RNAi screen. LD formation was prevented in human hepatoma cells overexpressing dominant-negative Rab1b. We thus hypothesized that Rab1b recruits lipid-synthesizing enzymes, facilitating LD growth. Here, FRET between diacylglycerol acyltransferase 2 (DGAT2) and Rab1b and activity mutants of the latter demonstrated that Rab1b promotes DGAT2 ER to the LD surface redistribution. Last, alterations in LD metabolism and DGAT2 redistribution, consistent with Rab1b activity, were caused by mutations in the Rab1b-GTPase activating protein TBC1D20 in Warburg Micro syndrome (WARBM) model mice fibroblasts. These data contribute to our understanding of the mechanism of Rab1b in LD homeostasis and WARBM, a devastating autosomal-recessive disorder caused by mutations in TBC1D20.
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Affiliation(s)
- Yehonathan Malis
- Department of Pathology, Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Shir Armoza-Eilat
- Department of Clinical Microbiology and Immunology, Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Inbar Nevo-Yassaf
- Department of Pathology, Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Anna Dukhovny
- Department of Clinical Microbiology and Immunology, Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Ella H. Sklan
- Department of Clinical Microbiology and Immunology, Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Koret Hirschberg
- Department of Pathology, Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
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3
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Kundu S, Jaiswal M, Babu Mullapudi V, Guo J, Kamat M, Basso KB, Guo Z. Investigation of Glycosylphosphatidylinositol (GPI)-Plasma Membrane Interaction in Live Cells and the Influence of GPI Glycan Structure on the Interaction. Chemistry 2024; 30:e202303047. [PMID: 37966101 PMCID: PMC10922586 DOI: 10.1002/chem.202303047] [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: 09/19/2023] [Revised: 11/05/2023] [Accepted: 11/15/2023] [Indexed: 11/16/2023]
Abstract
Glycosylphosphatidylinositols (GPIs) need to interact with other components in the cell membrane to transduce transmembrane signals. A bifunctional GPI probe was employed for photoaffinity-based proximity labelling and identification of GPI-interacting proteins in the cell membrane. This probe contained the entire core structure of GPIs and was functionalized with photoreactive diazirine and clickable alkyne to facilitate its crosslinking with proteins and attachment of an affinity tag. It was disclosed that this probe was more selective than our previously reported probe containing only a part structure of the GPI core for cell membrane incorporation and an improved probe for studying GPI-cell membrane interaction. Eighty-eight unique membrane proteins, many of which are related to GPIs/GPI-anchored proteins, were identified utilizing this probe. The proteomics dataset is a valuable resource for further analyses and data mining to find new GPI-related proteins and signalling pathways. A comparison of these results with those of our previous probe provided direct evidence for the profound impact of GPI glycan structure on its interaction with the cell membrane.
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Affiliation(s)
- Sayan Kundu
- Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
| | - Mohit Jaiswal
- Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
| | | | - Jiatong Guo
- Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
| | - Manasi Kamat
- Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
| | - Kari B Basso
- Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
| | - Zhongwu Guo
- Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
- UF Health Cancer Centre, University of Florida, Gainesville, FL 32611, USA
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4
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Papaioannou P, Wallace MJ, Malhotra N, Mohler PJ, El Refaey M. Biochemical Structure and Function of TRAPP Complexes in the Cardiac System. JACC Basic Transl Sci 2023; 8:1599-1612. [PMID: 38205348 PMCID: PMC10774597 DOI: 10.1016/j.jacbts.2023.03.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 03/14/2023] [Indexed: 01/12/2024]
Abstract
Trafficking protein particle (TRAPP) is well reported to play a role in the trafficking of protein products within the Golgi and endoplasmic reticulum. Dysfunction in TRAPP has been associated with disorders in the nervous and cardiovascular systems, but the majority of literature focuses on TRAPP function in the nervous system solely. Here, we highlight the known pathways of TRAPP and hypothesize potential impacts of TRAPP dysfunction on the cardiovascular system, particularly the role of TRAPP as a guanine-nucleotide exchange factor for Rab1 and Rab11. We also review the various cardiovascular phenotypes associated with changes in TRAPP complexes and their subunits.
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Affiliation(s)
- Peter Papaioannou
- Frick Center for Heart Failure and Arrhythmia Research, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
- Division of Cardiac Surgery, Department of Surgery, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Michael J. Wallace
- Frick Center for Heart Failure and Arrhythmia Research, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Nipun Malhotra
- Frick Center for Heart Failure and Arrhythmia Research, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
- Division of Cardiac Surgery, Department of Surgery, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Peter J. Mohler
- Frick Center for Heart Failure and Arrhythmia Research, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
- Division of Cardiovascular Medicine, Department of Internal Medicine, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Mona El Refaey
- Frick Center for Heart Failure and Arrhythmia Research, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
- Division of Cardiac Surgery, Department of Surgery, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
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5
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Lou G, Zhao Y, Zhao H, Zhang Y, Hao B, Qin L, Liu H, Liao S. Functional analysis of a novel nonsense variant c.91A>T of the TRAPPC2 gene in a Chinese family with X-linked recessive autosomal spondyloepiphyseal dysplasia tarda. Front Genet 2023; 14:1216592. [PMID: 37693308 PMCID: PMC10492639 DOI: 10.3389/fgene.2023.1216592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 07/10/2023] [Indexed: 09/12/2023] Open
Abstract
Spondyloepiphyseal dysplasia tarda (SEDT) is a condition involving late-onset, X-linked recessive skeletal dysplasia caused by mutations in the TRAPPC2 gene. In this paper, we identified a novel nonsense variant in a SEDT pedigree and analyzed the function of the variant in an attempt to explain the new pathogenesis of the TRAPPC2 protein in SEDT. Briefly, DNA and RNA samples from the peripheral blood of SEDT individuals were prepared. The causative variant in the Chinese SEDT family was identified by clinic whole-exome sequencing analysis. Then, we observed the mRNA expression of TRAPPC2 in patients and the mutant TRAPPC2 level in vitro and analyzed the protein stability and subcellular distribution by cell fluorescence and Western blotting. We also investigated the effect of TRAPPC2 knockdown on the expression and secretion of COL2A1 in SW1353 cells or primary human chondrocytes. Herein, we found a nonsense variant, c.91A>T, of the TRAPPC2 gene in the pedigree. TRAPPC2 mRNA expression levels were significantly decreased in the available peripheral blood cell samples of two affected patients. An in vitro study showed that the mutant plasmid exhibited significantly lower mRNA and protein of TRAPPC2, and the mutant protein changed its membrane distribution. TRAPPC2 knockdown resulted in decreased COL2A1 expression and collagen II secretions. Our data indicate that the novel nonsense variant, c.91A>T, of the TRAPPC2 gene is the cause of SEDT in this pedigree. The variant results in a lowered expression of TRAPPC2 and then affects the COL2A1 expression and collagen II secretions, which may explain the mechanism of loss of function of the variant.
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Affiliation(s)
- Guiyu Lou
- Henan Provincial People’s Hospital, Medical Genetics Institute of Henan Province, Henan Provincial Key Laboratory of Genetic Diseases and Functional Genomics, People’s Hospital of Zhengzhou University, Zhengzhou, China
| | - Yuanyin Zhao
- Department of Biochemistry and Molecular Biology, College of Basic Medical Science, Army Medical University, Chongqing, China
| | - Huiru Zhao
- Henan Provincial People’s Hospital, Medical Genetics Institute of Henan Province, Henan Provincial Key Laboratory of Genetic Diseases and Functional Genomics, People’s Hospital of Zhengzhou University, Zhengzhou, China
| | - Yuwei Zhang
- Henan Provincial People’s Hospital, Medical Genetics Institute of Henan Province, Henan Provincial Key Laboratory of Genetic Diseases and Functional Genomics, People’s Hospital of Zhengzhou University, Zhengzhou, China
| | - Bingtao Hao
- Henan Provincial People’s Hospital, Medical Genetics Institute of Henan Province, Henan Provincial Key Laboratory of Genetic Diseases and Functional Genomics, People’s Hospital of Zhengzhou University, Zhengzhou, China
| | - Litao Qin
- Henan Provincial People’s Hospital, Medical Genetics Institute of Henan Province, Henan Provincial Key Laboratory of Genetic Diseases and Functional Genomics, People’s Hospital of Zhengzhou University, Zhengzhou, China
| | - Hongyan Liu
- Henan Provincial People’s Hospital, Medical Genetics Institute of Henan Province, Henan Provincial Key Laboratory of Genetic Diseases and Functional Genomics, People’s Hospital of Zhengzhou University, Zhengzhou, China
| | - Shixiu Liao
- *Correspondence: Hongyan Liu, ; Shixiu Liao,
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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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7
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Xu Y, Zhang Z, Zhao Y, Zhao C, Shi M, Dong X, Zhang J, Tan L, Zhang L, Zhao Y. TRAPPC1 is essential for the maintenance and differentiation of common myeloid progenitors in mice. EMBO Rep 2023; 24:e55503. [PMID: 36440617 PMCID: PMC9900341 DOI: 10.15252/embr.202255503] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 11/14/2022] [Accepted: 11/17/2022] [Indexed: 11/29/2022] Open
Abstract
Myeloid cell development in bone marrow is essential for the maintenance of peripheral immune homeostasis. However, the role of intracellular protein trafficking pathways during myeloid cell differentiation is currently unknown. By mining bioinformatics data, we identify trafficking protein particle complex subunit 1 (TRAPPC1) as continuously upregulated during myeloid cell development. Using inducible ER-TRAPPC1 knockout mice and bone marrow chimeric mouse models, we demonstrate that TRAPPC1 deficiency causes severe monocyte and neutrophil defects, accompanied by a selective decrease in common myeloid progenitors (CMPs) and subsequent cell subsets in bone marrow. TRAPPC1-deleted CMPs differentiate poorly into monocytes and neutrophils in vivo and in vitro, in addition to exhibiting enhanced endoplasmic reticulum stress and apoptosis via a Ca2+ -mitochondria-dependent pathway. Cell cycle arrest and senescence of TRAPPC1-deleted CMPs are mediated by the activation of pancreatic endoplasmic reticulum kinase and the upregulation of cyclin-dependent kinase inhibitor p21. This study reveals the essential role of TRAPPC1 in the maintenance and differentiation of CMPs and highlights the significance of protein processing and trafficking processes in myeloid cell development.
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Affiliation(s)
- Yanan Xu
- State Key Laboratory of Membrane BiologyInstitute of Zoology, Chinese Academy of SciencesBeijingChina
| | - Zhaoqi Zhang
- State Key Laboratory of Membrane BiologyInstitute of Zoology, Chinese Academy of SciencesBeijingChina
- Cunji Medical SchoolUniversity of Chinese Academy of SciencesBeijingChina
| | - Yang Zhao
- State Key Laboratory of Membrane BiologyInstitute of Zoology, Chinese Academy of SciencesBeijingChina
| | - Chenxu Zhao
- State Key Laboratory of Membrane BiologyInstitute of Zoology, Chinese Academy of SciencesBeijingChina
- Cunji Medical SchoolUniversity of Chinese Academy of SciencesBeijingChina
| | - Mingpu Shi
- State Key Laboratory of Membrane BiologyInstitute of Zoology, Chinese Academy of SciencesBeijingChina
- Cunji Medical SchoolUniversity of Chinese Academy of SciencesBeijingChina
| | - Xue Dong
- State Key Laboratory of Membrane BiologyInstitute of Zoology, Chinese Academy of SciencesBeijingChina
- Cunji Medical SchoolUniversity of Chinese Academy of SciencesBeijingChina
| | - Jiayu Zhang
- State Key Laboratory of Membrane BiologyInstitute of Zoology, Chinese Academy of SciencesBeijingChina
- Cunji Medical SchoolUniversity of Chinese Academy of SciencesBeijingChina
| | - Liang Tan
- Kidney Transplantation DepartmentSecond Xiangya Hospital of Central South UniversityChangshaChina
| | - Lianfeng Zhang
- Key Laboratory of Human Diseases Comparative Medicine, Ministry of Health, Institute of Laboratory Animal ScienceChinese Academy of Medical Sciences, Peking Union Medical CollegeBeijingChina
| | - Yong Zhao
- State Key Laboratory of Membrane BiologyInstitute of Zoology, Chinese Academy of SciencesBeijingChina
- Cunji Medical SchoolUniversity of Chinese Academy of SciencesBeijingChina
- Beijing Institute for Stem Cell and Regenerative MedicineBeijingChina
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8
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Bagde SR, Fromme JC. The TRAPP complexes: discriminating GTPases in context. FEBS Lett 2022; 597:721-733. [PMID: 36481981 PMCID: PMC10050150 DOI: 10.1002/1873-3468.14557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2022] [Revised: 11/23/2022] [Accepted: 12/02/2022] [Indexed: 12/13/2022]
Abstract
Correct localization of Rab GTPases in cells is critical for proper function in membrane trafficking. Guanine-nucleotide exchange factors (GEFs) act as the primary determinants of Rab localization by activating and stabilizing their Rab substrates on specific organelle and vesicle membranes. The TRAPP complexes TRAPPII and TRAPPIII are two related GEFs that use the same catalytic site to activate distinct Rabs, Rab11 and Rab1, respectively. The Rab C-terminal hypervariable domain (HVD) is an important specificity determinant for the budding yeast TRAPP complexes, with the length of the HVD playing a critical role in counter-selection. Several recent studies have used cryo-EM to illuminate how the yeast and metazoan TRAPP complexes identify and activate their substrates. This review summarizes recently characterized Rab substrate selection mechanisms and highlights how the membrane surface provides critical context for the GEF-GTPase interactions.
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Affiliation(s)
- Saket R Bagde
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY, USA
| | - J Christopher Fromme
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY, USA
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9
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Oz N, Vayndorf EM, Tsuchiya M, McLean S, Turcios-Hernandez L, Pitt JN, Blue BW, Muir M, Kiflezghi MG, Tyshkovskiy A, Mendenhall A, Kaeberlein M, Kaya A. Evidence that conserved essential genes are enriched for pro-longevity factors. GeroScience 2022; 44:1995-2006. [PMID: 35695982 PMCID: PMC9616985 DOI: 10.1007/s11357-022-00604-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 06/03/2022] [Indexed: 02/02/2023] Open
Abstract
At the cellular level, many aspects of aging are conserved across species. This has been demonstrated by numerous studies in simple model organisms like Saccharomyces cerevisiae, Caenorhabdits elegans, and Drosophila melanogaster. Because most genetic screens examine loss of function mutations or decreased expression of genes through reverse genetics, essential genes have often been overlooked as potential modulators of the aging process. By taking the approach of increasing the expression level of a subset of conserved essential genes, we found that 21% of these genes resulted in increased replicative lifespan in S. cerevisiae. This is greater than the ~ 3.5% of genes found to affect lifespan upon deletion, suggesting that activation of essential genes may have a relatively disproportionate effect on increasing lifespan. The results of our experiments demonstrate that essential gene overexpression is a rich, relatively unexplored means of increasing eukaryotic lifespan.
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Affiliation(s)
- Naci Oz
- Department of Biology, Virginia Commonwealth University, Richmond, VA, 23284, USA
| | - Elena M Vayndorf
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, 98195, USA
| | - Mitsuhiro Tsuchiya
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, 98195, USA
| | - Samantha McLean
- Department of Biology, Virginia Commonwealth University, Richmond, VA, 23284, USA
| | | | - Jason N Pitt
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, 98195, USA
| | - Benjamin W Blue
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, 98195, USA
| | - Michael Muir
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, 98195, USA
| | - Michael G Kiflezghi
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, 98195, USA
| | - Alexander Tyshkovskiy
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Alexander Mendenhall
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, 98195, USA
| | - Matt Kaeberlein
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, 98195, USA.
| | - Alaattin Kaya
- Department of Biology, Virginia Commonwealth University, Richmond, VA, 23284, USA.
- Massey Cancer Center, Virginia Commonwealth University, Richmond, VA, 23298, USA.
- Department of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, VA, 23284, USA.
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10
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González Solís A, Berryman E, Otegui MS. Plant endosomes as protein sorting hubs. FEBS Lett 2022; 596:2288-2304. [PMID: 35689494 DOI: 10.1002/1873-3468.14425] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Revised: 05/28/2022] [Accepted: 05/31/2022] [Indexed: 01/10/2023]
Abstract
Endocytosis, secretion, and endosomal trafficking are key cellular processes that control the composition of the plasma membrane. Through the coordination of these trafficking pathways, cells can adjust the composition, localization, and turnover of proteins and lipids in response to developmental or environmental cues. Upon being incorporated into vesicles and internalized through endocytosis, plant plasma membrane proteins are delivered to the trans-Golgi network (TGN). At the TGN, plasma membrane proteins are recycled back to the plasma membrane or transferred to multivesicular endosomes (MVEs), where they are further sorted into intralumenal vesicles for degradation in the vacuole. Both types of plant endosomes, TGN and MVEs, act as sorting organelles for multiple endocytic, recycling, and secretory pathways. Molecular assemblies such as retromer, ESCRT (endosomal sorting complex required for transport) machinery, small GTPases, adaptor proteins, and SNAREs associate with specific domains of endosomal membranes to mediate different sorting and membrane-budding events. In this review, we discuss the mechanisms underlying the recognition and sorting of proteins at endosomes, membrane remodeling and budding, and their implications for cellular trafficking and physiological responses in plants.
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Affiliation(s)
- Ariadna González Solís
- Department of Botany and Center for Quantitative Cell Imaging, University of Wisconsin-Madison, WI, USA
| | - Elizabeth Berryman
- Department of Botany and Center for Quantitative Cell Imaging, University of Wisconsin-Madison, WI, USA
| | - Marisa S Otegui
- Department of Botany and Center for Quantitative Cell Imaging, University of Wisconsin-Madison, WI, USA
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11
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Rawlins LE, Almousa H, Khan S, Collins SC, Milev MP, Leslie J, Saint-Dic D, Khan V, Hincapie AM, Day JO, McGavin L, Rowley C, Harlalka GV, Vancollie VE, Ahmad W, Lelliott CJ, Gul A, Yalcin B, Crosby AH, Sacher M, Baple EL. Biallelic variants in TRAPPC10 cause a microcephalic TRAPPopathy disorder in humans and mice. PLoS Genet 2022; 18:e1010114. [PMID: 35298461 PMCID: PMC8963566 DOI: 10.1371/journal.pgen.1010114] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2021] [Revised: 03/29/2022] [Accepted: 02/20/2022] [Indexed: 11/25/2022] Open
Abstract
The highly evolutionarily conserved transport protein particle (TRAPP) complexes (TRAPP II and III) perform fundamental roles in subcellular trafficking pathways. Here we identified biallelic variants in TRAPPC10, a component of the TRAPP II complex, in individuals with a severe microcephalic neurodevelopmental disorder. Molecular studies revealed a weakened interaction between mutant TRAPPC10 and its putative adaptor protein TRAPPC2L. Studies of patient lymphoblastoid cells revealed an absence of TRAPPC10 alongside a concomitant absence of TRAPPC9, another key TRAPP II complex component associated with a clinically overlapping neurodevelopmental disorder. The TRAPPC9/10 reduction phenotype was recapitulated in TRAPPC10-/- knockout cells, which also displayed a membrane trafficking defect. Notably, both the reduction in TRAPPC9 levels and the trafficking defect in these cells could be rescued by wild type but not mutant TRAPPC10 gene constructs. Moreover, studies of Trappc10-/- knockout mice revealed neuroanatomical brain defects and microcephaly, paralleling findings seen in the human condition as well as in a Trappc9-/- mouse model. Together these studies confirm autosomal recessive TRAPPC10 variants as a cause of human disease and define TRAPP-mediated pathomolecular outcomes of importance to TRAPPC9 and TRAPPC10 mediated neurodevelopmental disorders in humans and mice. Microcephalic neurodevelopmental disorders are a group of conditions that are often inherited in families, involving small head size and abnormal brain development and function. This often results in delayed development of an affected child, affecting their movement, language and/or non-verbal communication and learning, as well as seizures and neuropsychiatric problems. A group of proteins called the transport protein particles (TRAPPs) are important for the transport of cargos inside cells. Alterations within a number of the TRAPP proteins have previously been associated with human inherited diseases called the ‘TRAPPopathies’, which involve neurodevelopmental and skeletal abnormalities. Here we show that TRAPPC10 gene alterations cause a new TRAPPopathy microcephalic neurodevelopmental disorder, and we provide a detailed clinical description of the condition termed ‘TRAPPC10-related disorder’. Our studies in mice lacking the TRAPPC10 gene identified similar features to those of affected humans, including small brain size and skeletal abnormalities. Our molecular studies showed that an affected individual with an alteration in the TRAPPC10 gene has no functional TRAPPC10 protein in their cells, which in turn causes a reduction in levels of another important TRAPP molecule, TRAPPC9. Cells lacking TRAPPC10 also display abnormalities in cellular transport processes. Together our data confirm alterations in TRAPPC10 as a cause of a microcephalic neurodevelopmental disorder in both humans and mice.
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Affiliation(s)
- Lettie E. Rawlins
- RILD Wellcome Wolfson Medical Research Centre, RD&E (Wonford) NHS Foundation Trust, University of Exeter Medical School, Exeter, United Kingdom
- Peninsula Clinical Genetics Service, Royal Devon & Exeter Hospital (Heavitree), Exeter, United Kingdom
| | - Hashem Almousa
- Department of Biology, Concordia University, Montreal, Quebec, Canada
| | - Shazia Khan
- RILD Wellcome Wolfson Medical Research Centre, RD&E (Wonford) NHS Foundation Trust, University of Exeter Medical School, Exeter, United Kingdom
- Department of Biological Sciences, International Islamic University, Islamabad, Pakistan
| | - Stephan C. Collins
- Institute of Genetics and Molecular and Cellular Biology, Inserm, Illkirch, France
- Inserm, University of Bourgogne Franche-Comté, Dijon, France
| | - Miroslav P. Milev
- Department of Biology, Concordia University, Montreal, Quebec, Canada
| | - Joseph Leslie
- RILD Wellcome Wolfson Medical Research Centre, RD&E (Wonford) NHS Foundation Trust, University of Exeter Medical School, Exeter, United Kingdom
| | - Djenann Saint-Dic
- Department of Biology, Concordia University, Montreal, Quebec, Canada
| | - Valeed Khan
- Department of Molecular Diagnostics, Rehman Medical Institute, Peshawar, Pakistan
| | | | - Jacob O. Day
- RILD Wellcome Wolfson Medical Research Centre, RD&E (Wonford) NHS Foundation Trust, University of Exeter Medical School, Exeter, United Kingdom
- Faculty of Health, University of Plymouth, Plymouth, United Kingdom
| | - Lucy McGavin
- University Hospitals Plymouth NHS Trust, Plymouth, United Kingdom
| | | | - Gaurav V. Harlalka
- RILD Wellcome Wolfson Medical Research Centre, RD&E (Wonford) NHS Foundation Trust, University of Exeter Medical School, Exeter, United Kingdom
- Department of Pharmacology, Rajarshi Shahu College of Pharmacy, Malvihir, Buldana, India
| | | | - Wasim Ahmad
- Department of Biochemistry, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan
| | | | - Asma Gul
- Department of Biological Sciences, International Islamic University, Islamabad, Pakistan
| | - Binnaz Yalcin
- Institute of Genetics and Molecular and Cellular Biology, Inserm, Illkirch, France
- Inserm, University of Bourgogne Franche-Comté, Dijon, France
| | - Andrew H. Crosby
- RILD Wellcome Wolfson Medical Research Centre, RD&E (Wonford) NHS Foundation Trust, University of Exeter Medical School, Exeter, United Kingdom
| | - Michael Sacher
- Department of Biology, Concordia University, Montreal, Quebec, Canada
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, Canada
| | - Emma L. Baple
- RILD Wellcome Wolfson Medical Research Centre, RD&E (Wonford) NHS Foundation Trust, University of Exeter Medical School, Exeter, United Kingdom
- Peninsula Clinical Genetics Service, Royal Devon & Exeter Hospital (Heavitree), Exeter, United Kingdom
- * E-mail:
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12
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An SJ, Rivera-Molina F, Anneken A, Xi Z, McNellis B, Polejaev VI, Toomre D. An active tethering mechanism controls the fate of vesicles. Nat Commun 2021; 12:5434. [PMID: 34521845 PMCID: PMC8440521 DOI: 10.1038/s41467-021-25465-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 08/05/2021] [Indexed: 11/09/2022] Open
Abstract
Vesicle tethers are thought to underpin the efficiency of intracellular fusion by bridging vesicles to their target membranes. However, the interplay between tethering and fusion has remained enigmatic. Here, through optogenetic control of either a natural tether-the exocyst complex-or an artificial tether, we report that tethering regulates the mode of fusion. We find that vesicles mainly undergo kiss-and-run instead of full fusion in the absence of functional exocyst. Full fusion is rescued by optogenetically restoring exocyst function, in a manner likely dependent on the stoichiometry of tether engagement with the plasma membrane. In contrast, a passive artificial tether produces mostly kissing events, suggesting that kiss-and-run is the default mode of vesicle fusion. Optogenetic control of tethering further shows that fusion mode has physiological relevance since only full fusion could trigger lamellipodial expansion. These findings demonstrate that active coupling between tethering and fusion is critical for robust membrane merger.
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Affiliation(s)
- Seong J An
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA
| | - Felix Rivera-Molina
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA
| | - Alexander Anneken
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA
| | - Zhiqun Xi
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA
| | - Brian McNellis
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA
| | - Vladimir I Polejaev
- International Science and Technology Center, Yale University School of Medicine, New Haven, CT, USA
| | - Derek Toomre
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA.
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13
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Joiner AMN, Phillips BP, Yugandhar K, Sanford EJ, Smolka MB, Yu H, Miller EA, Fromme JC. Structural basis of TRAPPIII-mediated Rab1 activation. EMBO J 2021; 40:e107607. [PMID: 34018207 PMCID: PMC8204860 DOI: 10.15252/embj.2020107607] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 04/07/2021] [Accepted: 04/11/2021] [Indexed: 12/17/2022] Open
Abstract
The GTPase Rab1 is a master regulator of the early secretory pathway and is critical for autophagy. Rab1 activation is controlled by its guanine nucleotide exchange factor, the multisubunit TRAPPIII complex. Here, we report the 3.7 Å cryo-EM structure of the Saccharomyces cerevisiae TRAPPIII complex bound to its substrate Rab1/Ypt1. The structure reveals the binding site for the Rab1/Ypt1 hypervariable domain, leading to a model for how the complex interacts with membranes during the activation reaction. We determined that stable membrane binding by the TRAPPIII complex is required for robust activation of Rab1/Ypt1 in vitro and in vivo, and is mediated by a conserved amphipathic α-helix within the regulatory Trs85 subunit. Our results show that the Trs85 subunit serves as a membrane anchor, via its amphipathic helix, for the entire TRAPPIII complex. These findings provide a structural understanding of Rab activation on organelle and vesicle membranes.
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Affiliation(s)
- Aaron MN Joiner
- Department of Molecular Biology and Genetics/Weill Institute for Cell and Molecular BiologyCornell UniversityIthacaNYUSA
| | | | - Kumar Yugandhar
- Department of Computational Biology/Weill Institute for Cell and Molecular BiologyCornell UniversityIthacaNYUSA
| | - Ethan J Sanford
- Department of Molecular Biology and Genetics/Weill Institute for Cell and Molecular BiologyCornell UniversityIthacaNYUSA
| | - Marcus B Smolka
- Department of Molecular Biology and Genetics/Weill Institute for Cell and Molecular BiologyCornell UniversityIthacaNYUSA
| | - Haiyuan Yu
- Department of Computational Biology/Weill Institute for Cell and Molecular BiologyCornell UniversityIthacaNYUSA
| | | | - J Christopher Fromme
- Department of Molecular Biology and Genetics/Weill Institute for Cell and Molecular BiologyCornell UniversityIthacaNYUSA
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14
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Highland CM, Fromme JC. Arf1 directly recruits the Pik1-Frq1 PI4K complex to regulate the final stages of Golgi maturation. Mol Biol Cell 2021; 32:1064-1080. [PMID: 33788598 PMCID: PMC8101487 DOI: 10.1091/mbc.e21-02-0069] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 03/11/2021] [Accepted: 03/12/2021] [Indexed: 12/21/2022] Open
Abstract
Proper Golgi complex function depends on the activity of Arf1, a GTPase whose effectors assemble and transport outgoing vesicles. Phosphatidylinositol 4-phosphate (PI4P) generated at the Golgi by the conserved PI 4-kinase Pik1 (PI4KIIIβ) is also essential for Golgi function, although its precise roles in vesicle formation are less clear. Arf1 has been reported to regulate PI4P production, but whether Pik1 is a direct Arf1 effector is not established. Using a combination of live-cell time-lapse imaging analyses, acute PI4P depletion experiments, and in vitro protein-protein interaction assays on Golgi-mimetic membranes, we present evidence for a model in which Arf1 initiates the final stages of Golgi maturation by tightly controlling PI4P production through direct recruitment of the Pik1-Frq1 PI4-kinase complex. This PI4P serves as a critical signal for AP-1 and secretory vesicle formation, the final events at maturing Golgi compartments. This work therefore establishes the regulatory and temporal context surrounding Golgi PI4P production and its precise roles in Golgi maturation.
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Affiliation(s)
- Carolyn M. Highland
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853
| | - J. Christopher Fromme
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853
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15
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ElMaghloob Y, Sot B, McIlwraith MJ, Garcia E, Yelland T, Ismail S. ARL3 activation requires the co-GEF BART and effector-mediated turnover. eLife 2021; 10:e64624. [PMID: 33438581 PMCID: PMC7817177 DOI: 10.7554/elife.64624] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Accepted: 01/12/2021] [Indexed: 12/28/2022] Open
Abstract
The ADP-ribosylation factor-like 3 (ARL3) is a ciliopathy G-protein which regulates the ciliary trafficking of several lipid-modified proteins. ARL3 is activated by its guanine exchange factor (GEF) ARL13B via an unresolved mechanism. BART is described as an ARL3 effector which has also been implicated in ciliopathies, although the role of its ARL3 interaction is unknown. Here, we show that, at physiological GTP:GDP levels, human ARL3GDP is weakly activated by ARL13B. However, BART interacts with nucleotide-free ARL3 and, in concert with ARL13B, efficiently activates ARL3. In addition, BART binds ARL3GTP and inhibits GTP dissociation, thereby stabilising the active G-protein; the binding of ARL3 effectors then releases BART. Finally, using live cell imaging, we show that BART accesses the primary cilium and colocalises with ARL13B. We propose a model wherein BART functions as a bona fide co-GEF for ARL3 and maintains the active ARL3GTP, until it is recycled by ARL3 effectors.
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Affiliation(s)
| | - Begoña Sot
- Fundación IMDEA-Nanociencia, Campus de CantoblancoMadridSpain
- Unidad Asociada de Nanobiotecnología (CNB-CSIC e IMDEA Nanociencia), Campus de CantoblancoMadridSpain
| | | | | | | | - Shehab Ismail
- CRUK- Beatson InstituteGlasgowUnited Kingdom
- Institute of Cancer Sciences, University of GlasgowGlasgowUnited Kingdom
- Department of Chemistry, KU Leuven, CelestijnenlaanHeverleeBelgium
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16
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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: 12] [Impact Index Per Article: 3.0] [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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17
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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: 20] [Impact Index Per Article: 5.0] [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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18
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Ueda S, Tamura N, Mima J. Membrane Tethering Potency of Rab-Family Small GTPases Is Defined by the C-Terminal Hypervariable Regions. Front Cell Dev Biol 2020; 8:577342. [PMID: 33102484 PMCID: PMC7554592 DOI: 10.3389/fcell.2020.577342] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 09/09/2020] [Indexed: 12/12/2022] Open
Abstract
Membrane tethering is a crucial step to determine the spatiotemporal specificity of secretory and endocytic trafficking pathways in all eukaryotic endomembrane systems. Recent biochemical studies by a chemically-defined reconstitution approach reveal that, in addition to the structurally-diverse classic tethering factors such as coiled-coil tethering proteins and multisubunit tethering complexes, Rab-family small GTPases also retain the inherent membrane tethering functions to directly and physically bridge two distinct lipid bilayers by themselves. Although Rab-mediated membrane tethering reactions are fairly efficient and specific in the physiological context, its mechanistic basis is yet to be understood. Here, to explore whether and how the intrinsic tethering potency of Rab GTPases is controlled by their C-terminal hypervariable region (HVR) domains that link the conserved small GTPase domains (G-domains) to membrane anchors at the C-terminus, we quantitatively compared tethering activities of two representative Rab isoforms in humans (Rab5a, Rab4a) and their HVR-deleted mutant forms. Strikingly, deletion of the HVR linker domains enabled both Rab5a and Rab4a isoforms to enhance their intrinsic tethering potency, exhibiting 5- to 50-fold higher initial velocities of tethering for the HVR-deleted mutants than those for the full-length, wild-type Rabs. Furthermore, we revealed that the tethering activity of full-length Rab5a was significantly reduced by the omission of anionic lipids and cholesterol from membrane lipids and, however, membrane tethering driven by HVR-deleted Rab5a mutant was completely insensitive to the headgroup composition of lipids. Reconstituted membrane tethering assays with the C-terminally-truncated mutants of Rab4a further uncovered that the N-terminal residues in the HVR linker, located adjacent to the G-domain, are critical for regulating the intrinsic tethering activity. In conclusion, our current findings establish that the non-conserved, flexible C-terminal HVR linker domains define membrane tethering potency of Rab-family small GTPases through controlling the close attachment of the globular G-domains to membrane surfaces, which confers the active tethering-competent state of the G-domains on lipid bilayers.
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Affiliation(s)
- Sanae Ueda
- Institute for Protein Research, Osaka University, Suita, Japan
| | - Naoki Tamura
- Institute for Protein Research, Osaka University, Suita, Japan
| | - Joji Mima
- Institute for Protein Research, Osaka University, Suita, Japan
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19
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Kehl A, Göser V, Reuter T, Liss V, Franke M, John C, Richter CP, Deiwick J, Hensel M. A trafficome-wide RNAi screen reveals deployment of early and late secretory host proteins and the entire late endo-/lysosomal vesicle fusion machinery by intracellular Salmonella. PLoS Pathog 2020; 16:e1008220. [PMID: 32658937 PMCID: PMC7377517 DOI: 10.1371/journal.ppat.1008220] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2019] [Revised: 07/23/2020] [Accepted: 05/19/2020] [Indexed: 12/17/2022] Open
Abstract
The intracellular lifestyle of Salmonella enterica is characterized by the formation of a replication-permissive membrane-bound niche, the Salmonella-containing vacuole (SCV). As a further consequence of the massive remodeling of the host cell endosomal system, intracellular Salmonella establish a unique network of various Salmonella-induced tubules (SIT). The bacterial repertoire of effector proteins required for the establishment for one type of these SIT, the Salmonella-induced filaments (SIF), is rather well-defined. However, the corresponding host cell proteins are still poorly understood. To identify host factors required for the formation of SIF, we performed a sub-genomic RNAi screen. The analyses comprised high-resolution live cell imaging to score effects on SIF induction, dynamics and morphology. The hits of our functional RNAi screen comprise: i) The late endo-/lysosomal SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) complex, consisting of STX7, STX8, VTI1B, and VAMP7 or VAMP8, which is, in conjunction with RAB7 and the homotypic fusion and protein sorting (HOPS) tethering complex, a complete vesicle fusion machinery. ii) Novel interactions with the early secretory GTPases RAB1A and RAB1B, providing a potential link to coat protein complex I (COPI) vesicles and reinforcing recently identified ties to the endoplasmic reticulum. iii) New connections to the late secretory pathway and/or the recycling endosome via the GTPases RAB3A, RAB8A, and RAB8B and the SNAREs VAMP2, VAMP3, and VAMP4. iv) An unprecedented involvement of clathrin-coated structures. The resulting set of hits allowed us to characterize completely new host factor interactions, and to strengthen observations from several previous studies. The facultative intracellular pathogen Salmonella enterica serovar Typhimurium induces the reorganization of the endosomal system of mammalian host cells. This activity is dependent on translocated effector proteins of the pathogen. The host cell factors required for endosomal remodeling are only partially known. To identify such factors for the formation and dynamics of endosomal compartments in Salmonella-infected cells, we performed a live cell imaging-based RNAi screen to investigate the role of 496 mammalian proteins involved in cellular logistics. We identified that endosomal remodeling by intracellular Salmonella is dependent on host factors in the following functional classes: i) the late endo-/lysosomal SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) complex, ii) the early secretory pathway, represented by regulator GTPases RAB1A and RAB1B, iii) the late secretory pathway and/or recycling endosomes represented by GTPases RAB3A, RAB8A, RAB8B, and the SNAREs VAMP2, VAMP3, and VAMP4, and iv) clathrin-coated structures. The identification of these new host factors provides further evidence for the complex manipulation of host cell transport functions by intracellular Salmonella and should enable detailed follow-up studies on the mechanisms involved.
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Affiliation(s)
- Alexander Kehl
- Division of Microbiology, University of Osnabrück, Osnabrück, Germany
- Division of Biophysics, University of Osnabrück, Osnabrück, Germany
- * E-mail: (AK); (MH)
| | - Vera Göser
- Division of Microbiology, University of Osnabrück, Osnabrück, Germany
| | - Tatjana Reuter
- Division of Microbiology, University of Osnabrück, Osnabrück, Germany
| | - Viktoria Liss
- Division of Microbiology, University of Osnabrück, Osnabrück, Germany
| | - Maximilian Franke
- Division of Microbiology, University of Osnabrück, Osnabrück, Germany
| | - Christopher John
- Division of Microbiology, University of Osnabrück, Osnabrück, Germany
| | | | - Jörg Deiwick
- Division of Microbiology, University of Osnabrück, Osnabrück, Germany
| | - Michael Hensel
- Division of Microbiology, University of Osnabrück, Osnabrück, Germany
- CellNanOs–Center for Cellular Nanoanalytics, Fachbereich Biologie/Chemie, Universität Osnabrück, Osnabrück, Germany
- * E-mail: (AK); (MH)
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20
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Zhang C, Li C, Siu GKY, Luo X, Yu S. Distinct Roles of TRAPPC8 and TRAPPC12 in Ciliogenesis via Their Interactions With OFD1. Front Cell Dev Biol 2020; 8:148. [PMID: 32258032 PMCID: PMC7090148 DOI: 10.3389/fcell.2020.00148] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 02/21/2020] [Indexed: 01/08/2023] Open
Abstract
The transport protein particle (TRAPP) complex was initially identified as a tethering factor for COPII vesicle. Subsequently, three forms (TRAPPI, II, and III) have been found and TRAPPIII has been reported to serve as a regulator in autophagy. This study investigates a new role of mammalian TRAPPIII in ciliogenesis. We found a ciliopathy protein, oral-facial-digital syndrome 1 (OFD1), interacting with the TRAPPIII-specific subunits TRAPPC8 and TRAPPC12. TRAPPC8 is necessary for the association of OFD1 with pericentriolar material 1 (PCM1). Its depletion reduces the extent of colocalized signals between OFD1 and PCM1, but does not compromise the structural integrity of centriolar satellites. The interaction between TRAPPC8 and OFD1 inhibits that between OFD1 and TRAPPC12, suggesting different roles of TRAPPIII-specific subunits in ciliogenesis and explaining the differences in cilium lengths in TRAPPC8-depleted and TRAPPC12-depleted hTERT-RPE1 cells. On the other hand, TRAPPC12 depletion causes increased ciliary length because TRAPPC12 is required for the disassembly of primary cilia. Overall, this study has revealed different roles of TRAPPC8 and TRAPPC12 in the assembly of centriolar satellites and demonstrated a possible tethering role of TRAPPIII during ciliogenesis.
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Affiliation(s)
- Caiyun Zhang
- School of Biomedical Sciences, The Chinese University of Hong Kong, Sha Tin, China
| | - Chunman Li
- Department of Anatomy, Histology and Developmental Biology, School of Basic Medical Sciences, Shenzhen University Health Science Centre, Shenzhen, China
| | - Gavin Ka Yu Siu
- School of Biomedical Sciences, The Chinese University of Hong Kong, Sha Tin, China
| | - Xiaomin Luo
- School of Biomedical Sciences, The Chinese University of Hong Kong, Sha Tin, China
| | - Sidney Yu
- School of Biomedical Sciences, The Chinese University of Hong Kong, Sha Tin, China
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21
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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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22
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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: 18] [Impact Index Per Article: 3.6] [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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23
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Milev MP, Stanga D, Schänzer A, Nascimento A, Saint-Dic D, Ortez C, Natera-de Benito D, Barrios DG, Colomer J, Badosa C, Jou C, Gallano P, Gonzalez-Quereda L, Töpf A, Johnson K, Straub V, Hahn A, Sacher M, Jimenez-Mallebrera C. Characterization of three TRAPPC11 variants suggests a critical role for the extreme carboxy terminus of the protein. Sci Rep 2019; 9:14036. [PMID: 31575891 PMCID: PMC6773699 DOI: 10.1038/s41598-019-50415-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Accepted: 09/11/2019] [Indexed: 12/23/2022] Open
Abstract
TRAPPC11 was identified as a component of the TRAPP III complex that functions in membrane trafficking and autophagy. Variants in TRAPPC11 have been reported to be associated with a broad spectrum of phenotypes but all affected individuals display muscular pathology. Identifying additional variants will further our understanding of the clinical spectrum of phenotypes and will reveal regions of the protein critical for its functions. Here we report three individuals from unrelated families that have bi-allellic TRAPPC11 variants. Subject 1 harbors a compound heterozygous variant (c.1287 + 5G > A and c.3379_3380insT). The former variant results in a partial deletion of the foie gras domain (p.Ala372_Ser429del), while the latter variant results in a frame-shift and extension at the carboxy terminus (p.Asp1127Valfs*47). Subjects 2 and 3 both harbour a homozygous missense variant (c.2938G > A; p.Gly980Arg). Fibroblasts from all three subjects displayed membrane trafficking defects manifested as delayed endoplasmic reticulum (ER)-to-Golgi transport and/or a delay in protein exit from the Golgi. All three individuals also show a defect in glycosylation of an ER-resident glycoprotein. However, only the compound heterozygous subject displayed an autophagic flux defect. Collectively, our characterization of these individuals with bi-allelic TRAPPC11 variants highlights the functional importance of the carboxy-terminal portion of the protein.
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Affiliation(s)
- Miroslav P Milev
- Concordia University, Department of Biology, Montreal, Quebec, Canada
| | - Daniela Stanga
- Concordia University, Department of Biology, Montreal, Quebec, Canada
| | - Anne Schänzer
- Institute of Neuropathology, Justus Liebig University Giessen, Giessen, Germany
| | - Andrés Nascimento
- Neuromuscular Unit, Neuropaediatrics Department, Hospital Sant Joan de Déu, Institut de Recerca Sant Joan de Déu, Barcelona, Spain.,U705 and U703 Center for Biomedical Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Djenann Saint-Dic
- Concordia University, Department of Biology, Montreal, Quebec, Canada
| | - Carlos Ortez
- Neuromuscular Unit, Neuropaediatrics Department, Hospital Sant Joan de Déu, Institut de Recerca Sant Joan de Déu, Barcelona, Spain
| | - Daniel Natera-de Benito
- Neuromuscular Unit, Neuropaediatrics Department, Hospital Sant Joan de Déu, Institut de Recerca Sant Joan de Déu, Barcelona, Spain
| | - Desiré González Barrios
- Servicio de Pediatría, Hospital Universitario Nuestra Señora de Candelaria, Santa Cruz de Tenerife, Spain
| | - Jaume Colomer
- Neuromuscular Unit, Neuropaediatrics Department, Hospital Sant Joan de Déu, Institut de Recerca Sant Joan de Déu, Barcelona, Spain
| | - Carmen Badosa
- Neuromuscular Unit, Neuropaediatrics Department, Hospital Sant Joan de Déu, Institut de Recerca Sant Joan de Déu, Barcelona, Spain
| | - Cristina Jou
- U705 and U703 Center for Biomedical Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain.,Pathology Department and Biobank, Hospital Sant Joan de Déu, Institut de Recerca Sant Joan de Déu, Barcelona, Spain
| | - Pia Gallano
- U705 and U703 Center for Biomedical Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain.,Servicio de Genética, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| | - Lidia Gonzalez-Quereda
- U705 and U703 Center for Biomedical Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain.,Servicio de Genética, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| | - Ana Töpf
- The John Walton Muscular Dystrophy Research Centre, Institute of Genetic Medicine, Newcastle University and Newcastle Hospitals NHS Foundation Trust, Newcastle-upon-Tyne, UK
| | - Katherine Johnson
- The John Walton Muscular Dystrophy Research Centre, Institute of Genetic Medicine, Newcastle University and Newcastle Hospitals NHS Foundation Trust, Newcastle-upon-Tyne, UK.,Institute of Cellular Medicine, Newcastle University, Newcastle-upon-Tyne, UK
| | - Volker Straub
- The John Walton Muscular Dystrophy Research Centre, Institute of Genetic Medicine, Newcastle University and Newcastle Hospitals NHS Foundation Trust, Newcastle-upon-Tyne, UK
| | - Andreas Hahn
- Department of Child Neurology, Justus Liebig University Giessen, Giessen, Germany.
| | - Michael Sacher
- Concordia University, Department of Biology, Montreal, Quebec, Canada. .,McGill University, Department of Anatomy and Cell Biology, Montreal, Quebec, Canada.
| | - Cecilia Jimenez-Mallebrera
- Neuromuscular Unit, Neuropaediatrics Department, Hospital Sant Joan de Déu, Institut de Recerca Sant Joan de Déu, Barcelona, Spain. .,U705 and U703 Center for Biomedical Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain.
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24
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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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25
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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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26
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Stanga D, Zhao Q, Milev MP, Saint-Dic D, Jimenez-Mallebrera C, Sacher M. TRAPPC11 functions in autophagy by recruiting ATG2B-WIPI4/WDR45 to preautophagosomal membranes. Traffic 2019; 20:325-345. [PMID: 30843302 DOI: 10.1111/tra.12640] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Revised: 03/04/2019] [Accepted: 03/05/2019] [Indexed: 01/01/2023]
Abstract
TRAPPC11 has been implicated in membrane traffic and lipid-linked oligosaccharide synthesis, and mutations in TRAPPC11 result in neuromuscular and developmental phenotypes. Here, we show that TRAPPC11 has a role upstream of autophagosome formation during macroautophagy. Upon TRAPPC11 depletion, LC3-positive membranes accumulate prior to, and fail to be cleared during, starvation. A proximity biotinylation assay identified ATG2B and its binding partner WIPI4/WDR45 as TRAPPC11 interactors. TRAPPC11 depletion phenocopies that of ATG2 and WIPI4 and recruitment of both proteins to membranes is defective upon reduction of TRAPPC11. We find that a portion of TRAPPC11 and other TRAPP III proteins localize to isolation membranes. Fibroblasts from a patient with TRAPPC11 mutations failed to recruit ATG2B-WIPI4, suggesting that this interaction is physiologically relevant. Since ATG2B-WIPI4 is required for isolation membrane expansion, our study suggests that TRAPPC11 plays a role in this process. We propose a model whereby the TRAPP III complex participates in the formation and expansion of the isolation membrane at several steps.
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Affiliation(s)
- Daniela Stanga
- Concordia University, Department of Biology, Montreal, Quebec, Canada
| | - Qingchuan Zhao
- University of Montreal, Department of Medicine and Institute for Research in Immunology and Cancer, Montreal, Quebec, Canada
| | - Miroslav P Milev
- Concordia University, Department of Biology, Montreal, Quebec, Canada
| | - Djenann Saint-Dic
- Concordia University, Department of Biology, Montreal, Quebec, Canada
| | - Cecilia Jimenez-Mallebrera
- Neuromuscular Unit, Neuropaediatrics Department, Institut de Recerca Sant Joan de Déu, Hospital Sant Joan de Déu and CIBERER, Barcelona, Spain
| | - Michael Sacher
- Concordia University, Department of Biology, Montreal, Quebec, Canada.,McGill University, Department of Anatomy and Cell Biology, Quebec, Canada
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27
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Mitter AL, Schlotterhose P, Krick R. Gyp1 has a dual function as Ypt1 GAP and interaction partner of Atg8 in selective autophagy. Autophagy 2019; 15:1031-1050. [PMID: 30686108 DOI: 10.1080/15548627.2019.1569929] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Macroautophagy/autophagy is a highly conserved intracellular vesicle transport pathway that prevents accumulation of harmful materials within cells. The dynamic assembly and disassembly of the different autophagic protein complexes at the so-called phagophore assembly site (PAS) is strictly regulated. Rab GTPases are major regulators of cellular vesicle trafficking, and the Rab GTPase Ypt1 and its GEF TRAPPIII have been implicated in autophagy. We show that Gyp1 acts as a Ypt1 GTPase-activating protein (GAP) for selective autophagic variants, such as the Cvt pathway or the selective autophagic degradation of mitochondria (mitophagy). Gyp1 regulates the dynamic disassembly of the conserved Ypt1-Atg1 complex. Thereby, Gyp1 sets the stage for efficient Atg14 recruitment, and facilitates the critical step from nucleation to elongation of the phagophore. In addition, we identified Gyp1 as a new Atg8-interacting motif (AIM)-dependent Atg8 interaction partner. The Gyp1 AIM is required for efficient formation of the cargo receptor-Atg8 complexes. Our findings elucidate the molecular mechanisms of complex disassembly during phagophore formation and suggest potential dual functions of GAPs in cellular vesicle trafficking. Abbreviations AIM, Atg8-interacting motif; Atg, autophagy related; Cvt, cytoplasm-to-vacuole targeting; GAP, GTPase-activating protein; GEF, guanine-nucleotide exchange factor; GFP, green fluorescent protein; log phase, logarithmic growth phase; NHD, N-terminal helical domain; PAS, phagophore assembly site; PE, phosphatidylethanolamine; PtdIns3P, phosphatidylinositol-3-phosphate; WT, wild-type.
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Affiliation(s)
- Anne Lisa Mitter
- a Department of Cellular Biochemistry, University Medicine , Georg-August University , Goettingen , Germany
| | - Petra Schlotterhose
- a Department of Cellular Biochemistry, University Medicine , Georg-August University , Goettingen , Germany
| | - Roswitha Krick
- a Department of Cellular Biochemistry, University Medicine , Georg-August University , Goettingen , Germany
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28
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Thomas LL, van der Vegt SA, Fromme JC. A Steric Gating Mechanism Dictates the Substrate Specificity of a Rab-GEF. Dev Cell 2018; 48:100-114.e9. [PMID: 30528786 DOI: 10.1016/j.devcel.2018.11.013] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 10/23/2018] [Accepted: 11/07/2018] [Indexed: 10/27/2022]
Abstract
Correct localization of Rab GTPases in cells is critical for proper function in membrane trafficking, yet the mechanisms that target Rabs to specific subcellular compartments remain controversial. Guanine nucleotide exchange factors (GEFs) activate and consequently stabilize Rab substrates on membranes, thus implicating GEFs as the primary determinants of Rab localization. A competing hypothesis is that the Rab C-terminal hypervariable domain (HVD) serves as a subcellular targeting signal. In this study, we present a unifying mechanism in which the HVD controls targeting of certain Rabs by mediating interaction with their GEFs. We demonstrate that the TRAPP complexes, two related GEFs that use the same catalytic site to activate distinct Rabs, distinguish between Ypt1 (Rab1) and Ypt31/32 (Rab11) via their divergent HVDs. Remarkably, we find that HVD length gates Rab access to the TRAPPII complex by constraining the distance between the nucleotide-binding domain and the membrane surface.
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Affiliation(s)
- Laura L Thomas
- Department of Molecular Biology and Genetics/Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA
| | - Solveig A van der Vegt
- Department of Molecular Biology and Genetics/Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA
| | - J Christopher Fromme
- Department of Molecular Biology and Genetics/Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA.
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29
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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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Mbimba T, Hussein NJ, Najeed A, Safadi FF. TRAPPC9: Novel insights into its trafficking and signaling pathways in health and disease (Review). Int J Mol Med 2018; 42:2991-2997. [PMID: 30272317 DOI: 10.3892/ijmm.2018.3889] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 08/14/2018] [Indexed: 11/06/2022] Open
Abstract
Trafficking protein particle complex 9 (TRAPPC9) is a protein subunit of the transport protein particle II (TRAPPII), which has been reported to be important in the trafficking of cargo from the endoplasmic reticulum (ER) to the Golgi, and in intra‑Golgi and endosome‑to‑Golgi transport in yeast cells. In mammalian cells, TRAPPII has been shown to be important in Golgi vesicle tethering and intra‑Golgi transport. TRAPPC9 is considered to be a novel molecule capable of modulating the activation of nuclear factor‑κB (NF‑κB). Mutations in TRAPPC9 have been linked to a rare consanguineous hereditary form of mental retardation, as part of the NF‑κB pathways. In addition, TRAPPC9 has been reported to be involved in breast and colon cancer and liver diseases. The present review highlights the most recent publications on the structure, expression and function of TRAPPC9, and its association with various human diseases.
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Affiliation(s)
- Thomas Mbimba
- Department of Anatomy and Neurobiology, College of Medicine, Northeast Ohio Medical University, Rootstown, OH 44272, USA
| | - Nazar J Hussein
- Department of Anatomy and Neurobiology, College of Medicine, Northeast Ohio Medical University, Rootstown, OH 44272, USA
| | - Ayesha Najeed
- Department of Anatomy and Neurobiology, College of Medicine, Northeast Ohio Medical University, Rootstown, OH 44272, USA
| | - Fayez F Safadi
- Department of Anatomy and Neurobiology, College of Medicine, Northeast Ohio Medical University, Rootstown, OH 44272, USA
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Milev MP, Graziano C, Karall D, Kuper WFE, Al-Deri N, Cordelli DM, Haack TB, Danhauser K, Iuso A, Palombo F, Pippucci T, Prokisch H, Saint-Dic D, Seri M, Stanga D, Cenacchi G, van Gassen KLI, Zschocke J, Fauth C, Mayr JA, Sacher M, van Hasselt PM. Bi-allelic mutations in TRAPPC2L result in a neurodevelopmental disorder and have an impact on RAB11 in fibroblasts. J Med Genet 2018; 55:753-764. [DOI: 10.1136/jmedgenet-2018-105441] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 06/18/2018] [Accepted: 07/12/2018] [Indexed: 12/28/2022]
Abstract
BackgroundThe combination of febrile illness-induced encephalopathy and rhabdomyolysis has thus far only been described in disorders that affect cellular energy status. In the absence of specific metabolic abnormalities, diagnosis can be challenging.ObjectiveThe objective of this study was to identify and characterise pathogenic variants in two individuals from unrelated families, both of whom presented clinically with a similar phenotype that included neurodevelopmental delay, febrile illness-induced encephalopathy and episodes of rhabdomyolysis, followed by developmental arrest, epilepsy and tetraplegia.MethodsWhole exome sequencing was used to identify pathogenic variants in the two individuals. Biochemical and cell biological analyses were performed on fibroblasts from these individuals and a yeast two-hybrid analysis was used to assess protein-protein interactions.ResultsProbands shared a homozygous TRAPPC2L variant (c.109G>T) resulting in a p.Asp37Tyr missense variant. TRAPPC2L is a component of transport protein particle (TRAPP), a group of multisubunit complexes that function in membrane traffic and autophagy. Studies in patient fibroblasts as well as in a yeast system showed that the p.Asp37Tyr protein was present but not functional and resulted in specific membrane trafficking delays. The human missense mutation and the analogous mutation in the yeast homologue Tca17 ablated the interaction between TRAPPC2L and TRAPPC10/Trs130, a component of the TRAPP II complex. Since TRAPP II activates the GTPase RAB11, we examined the activation state of this protein and found increased levels of the active RAB, correlating with changes in its cellular morphology.ConclusionsOur study implicates a RAB11 pathway in the aetiology of the TRAPPC2L disorder and has implications for other TRAPP-related disorders with similar phenotypes.
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Riedel F, Galindo A, Muschalik N, Munro S. The two TRAPP complexes of metazoans have distinct roles and act on different Rab GTPases. J Cell Biol 2017; 217:601-617. [PMID: 29273580 PMCID: PMC5800803 DOI: 10.1083/jcb.201705068] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 10/19/2017] [Accepted: 11/27/2017] [Indexed: 12/03/2022] Open
Abstract
In yeast, the TRAPP complexes activate Rab1 with TRAPPII also activating Rab11, but less is known about the two TRAPPs in metazoans. Riedel et al. show that in Drosophila melanogaster, TRAPPIII is an essential Rab1 activator, and TRAPPII activates Rab1 and Rab11 and becomes essential when an unrelated Rab11 activator is deleted. Originally identified in yeast, transport protein particle (TRAPP) complexes are Rab GTPase exchange factors that share a core set of subunits. TRAPPs were initially found to act on Ypt1, the yeast orthologue of Rab1, but recent studies have found that yeast TRAPPII can also activate the Rab11 orthologues Ypt31/32. Mammals have two TRAPP complexes, but their role is less clear, and they contain subunits that are not found in the yeast complexes but are essential for cell growth. To investigate TRAPP function in metazoans, we show that Drosophila melanogaster have two TRAPP complexes similar to those in mammals and that both activate Rab1, whereas one, TRAPPII, also activates Rab11. TRAPPII is not essential but becomes so in the absence of the gene parcas that encodes the Drosophila orthologue of the SH3BP5 family of Rab11 guanine nucleotide exchange factors (GEFs). Thus, in metazoans, Rab1 activation requires TRAPP subunits not found in yeast, and Rab11 activation is shared by TRAPPII and an unrelated GEF that is metazoan specific.
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Affiliation(s)
- Falko Riedel
- Medical Research Council Laboratory of Molecular Biology, Cambridge, England, UK
| | - Antonio Galindo
- Medical Research Council Laboratory of Molecular Biology, Cambridge, England, UK
| | - Nadine Muschalik
- Medical Research Council Laboratory of Molecular Biology, Cambridge, England, UK
| | - Sean Munro
- Medical Research Council Laboratory of Molecular Biology, Cambridge, England, UK
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Ravikumar R, Steiner A, Assaad FF. Multisubunit tethering complexes in higher plants. CURRENT OPINION IN PLANT BIOLOGY 2017; 40:97-105. [PMID: 28889036 DOI: 10.1016/j.pbi.2017.08.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Revised: 07/21/2017] [Accepted: 08/18/2017] [Indexed: 05/23/2023]
Abstract
Tethering complexes mediate the initial, specific contact between donor and acceptor membranes. This review focuses on the modularity and function of multisubunit tethering complexes (MTCs) in higher plants. One emphasis is on molecular interactions of plant MTCs. Here, a number of insights have been gained concerning interactions between different tethering complexes, and between tethers and microtubule-associated proteins. The roles of tethering complexes in abiotic stress responses appear indirect, but in the context of biotic stress responses it has been suggested that some tethers are direct targets of pathogen effectors or virulence factors. In light of the central roles tethering complexes play in plant development, an emerging concept is that tethers may be co-opted for plant adaptive responses.
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Affiliation(s)
| | | | - Farhah F Assaad
- Botany, Technische Universität München, 85354 Freising, Germany.
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Thomas LL, Joiner AMN, Fromme JC. The TRAPPIII complex activates the GTPase Ypt1 (Rab1) in the secretory pathway. J Cell Biol 2017; 217:283-298. [PMID: 29109089 PMCID: PMC5748984 DOI: 10.1083/jcb.201705214] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 09/01/2017] [Accepted: 10/03/2017] [Indexed: 12/30/2022] Open
Abstract
The TRAPP complexes are nucleotide exchange factors that activate Rab GTPases, and four different versions of TRAPP have been reported. Thomas et al. show that only two versions of TRAPP are detectable in normal cells and demonstrate that the TRAPPIII complex regulates Golgi trafficking in addition to its established role in autophagy. Rab GTPases serve as molecular switches to regulate eukaryotic membrane trafficking pathways. The transport protein particle (TRAPP) complexes activate Rab GTPases by catalyzing GDP/GTP nucleotide exchange. In mammalian cells, there are two distinct TRAPP complexes, yet in budding yeast, four distinct TRAPP complexes have been reported. The apparent differences between the compositions of yeast and mammalian TRAPP complexes have prevented a clear understanding of the specific functions of TRAPP complexes in all cell types. In this study, we demonstrate that akin to mammalian cells, wild-type yeast possess only two TRAPP complexes, TRAPPII and TRAPPIII. We find that TRAPPIII plays a major role in regulating Rab activation and trafficking at the Golgi in addition to its established role in autophagy. These disparate pathways share a common regulatory GTPase Ypt1 (Rab1) that is activated by TRAPPIII. Our findings lead to a simple yet comprehensive model for TRAPPIII function in both normal and starved eukaryotic cells.
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Affiliation(s)
- Laura L Thomas
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY
| | - Aaron M N Joiner
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY
| | - J Christopher Fromme
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY
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Mutations in TRAPPC12 Manifest in Progressive Childhood Encephalopathy and Golgi Dysfunction. Am J Hum Genet 2017; 101:291-299. [PMID: 28777934 DOI: 10.1016/j.ajhg.2017.07.006] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Accepted: 07/06/2017] [Indexed: 12/23/2022] Open
Abstract
Progressive childhood encephalopathy is an etiologically heterogeneous condition characterized by progressive central nervous system dysfunction in association with a broad range of morbidity and mortality. The causes of encephalopathy can be either non-genetic or genetic. Identifying the genetic causes and dissecting the underlying mechanisms are critical to understanding brain development and improving treatments. Here, we report that variants in TRAPPC12 result in progressive childhood encephalopathy. Three individuals from two unrelated families have either a homozygous deleterious variant (c.145delG [p.Glu49Argfs∗14]) or compound-heterozygous variants (c.360dupC [p.Glu121Argfs∗7] and c.1880C>T [p. Ala627Val]). The clinical phenotypes of the three individuals are strikingly similar: severe disability, microcephaly, hearing loss, spasticity, and characteristic brain imaging findings. Fibroblasts derived from all three individuals showed a fragmented Golgi that could be rescued by expression of wild-type TRAPPC12. Protein transport from the endoplasmic reticulum to and through the Golgi was delayed. TRAPPC12 is a member of the TRAPP protein complex, which functions in membrane trafficking. Variants in several other genes encoding members of the TRAPP complex have been associated with overlapping clinical presentations, indicating shared and distinct functions for each complex member. Detailed understanding of the TRAPP-opathies will illuminate the role of membrane protein transport in human disease.
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36
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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: 19] [Impact Index Per Article: 2.7] [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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Abstract
Protein secretion mediated by the secretory transport pathway is an important cellular process in eukaryotic cells. In the conventional secretory transport pathway, newly synthesized proteins pass through several endomembrane compartments en route to their specific destinations. Transport of secretory proteins between different compartments is shuttled by small, membrane-enclosed vesicles. To ensure the fidelity of transport, eukaryotic cells employ elaborate molecular machineries to accurately sort newly synthesized proteins into specific transport vesicles and precisely deliver these transport vesicles to distinct acceptor compartments. In this review, we summarize the molecular machineries that regulate each step of vesicular transport in the secretory transport pathway in yeast and animal cells.
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Affiliation(s)
- Yusong Guo
- Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.
| | - Feng Yang
- Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Xiao Tang
- Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
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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: 74] [Impact Index Per Article: 9.3] [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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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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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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Aso Y, Nakamura K, Kimura N, Takemaru M, Arakawa R, Fujiki M, Hirano T, Kumamoto T, Matsubara E. Induction of Genes Expressed in Endothelial Cells of the Corpus Callosum in the Chronic Cerebral Hypoperfusion Rat Model. Pathobiology 2016; 84:25-37. [PMID: 27458816 DOI: 10.1159/000446876] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 05/17/2016] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Cerebrovascular white matter lesions (WMLs) are associated with cognitive impairment in patients with subcortical vascular dementia. We performed a comprehensive gene expression analysis to elucidate genes associated with WML development in a chronic cerebral hypoperfusion rat model. METHODS Brains of rats with bilateral carotid ligation (2VO, n = 10) and sham-operated rats (n = 5-10/group) were removed on days 1, 7, or 28 after surgery. Total RNA isolated from the corpus callosum was evaluated by microarray analysis and quantitative reverse transcription-polymerase chain reaction. RESULTS On days 7 and 28, WMLs exhibited histologic changes. On day 7, 16 genes were differentially expressed between groups. mRNA levels of Ptprb, Kcnj8, Crispld2, Bcl6b, and Gja5 were differentially expressed in 2VO rats on day 7, but then returned to normal, whereas mRNA levels of Vwf and Trappc6a were upregulated after day 7. Immunohistochemistry showed that GJA5 and vWF were detected in endothelial cells, KCNJ8 in endothelial cells and astrocytes, CRISPLD2 in neurons and astrocytes, and TRAPPC6A in neurons. CONCLUSION Our findings indicate novel genes that may be associated with WML development in the chronic cerebral hypoperfusion rat model, and suggest an important role of neurovascular dysfunction in the pathophysiology.
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Affiliation(s)
- Yasuhiro Aso
- Department of Neurology, Faculty of Medicine, Oita University, Oita, Japan
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42
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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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Mukherjee I, Barlowe C. Overexpression of Sly41 suppresses COPII vesicle-tethering deficiencies by elevating intracellular calcium levels. Mol Biol Cell 2016; 27:1635-49. [PMID: 27030673 PMCID: PMC4865320 DOI: 10.1091/mbc.e15-10-0704] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Accepted: 03/22/2016] [Indexed: 11/29/2022] Open
Abstract
SLY41 is a multicopy suppressor of mutations in the essential Ypt1 GTPase. Overexpression of Sly41 elevates cytosolic Ca2+ concentration, which stimulates SNARE-dependent fusion of COPII vesicles with Golgi membranes and suppresses deficiencies in Ypt1-dependent vesicle tethering. Thus Ca2+ positively regulates vesicle fusion with Golgi membranes. SLY41 was identified as a multicopy suppressor of loss of Ypt1, a Rab GTPase essential for COPII vesicle tethering at the Golgi complex. SLY41 encodes a polytopic membrane protein with homology to a class of solute transporter proteins, but how overexpression suppresses vesicle-tethering deficiencies is not known. Here we show that Sly41 is efficiently packaged into COPII vesicles and actively cycles between the ER and Golgi compartments. SLY41 displays synthetic negative genetic interactions with PMR1, which encodes the major Golgi-localized Ca2+/Mn2+ transporter and suggests that Sly41 influences cellular Ca2+ and Mn2+ homeostasis. Experiments using the calcium probe aequorin to measure intracellular Ca2+ concentrations in live cells reveal that Sly41 overexpression significantly increases cytosolic calcium levels. Although specific substrates of the Sly41 transporter were not identified, our findings indicate that localized overexpression of Sly41 to the early secretory pathway elevates cytosolic calcium levels to suppress vesicle-tethering mutants. In vitro SNARE cross-linking assays were used to directly monitor the influence of Ca2+ on tethering and fusion of COPII vesicles with Golgi membranes. Strikingly, calcium at suppressive concentrations stimulated SNARE-dependent membrane fusion when vesicle-tethering activity was reduced. These results show that calcium positively regulates the SNARE-dependent fusion stage of ER–Golgi transport.
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Affiliation(s)
- Indrani Mukherjee
- Department of Biochemistry, Geisel School of Medicine at Dartmouth, Hanover, NH 03755
| | - Charles Barlowe
- Department of Biochemistry, Geisel School of Medicine at Dartmouth, Hanover, NH 03755
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Dubuke ML, Munson M. The Secret Life of Tethers: The Role of Tethering Factors in SNARE Complex Regulation. Front Cell Dev Biol 2016; 4:42. [PMID: 27243006 PMCID: PMC4860414 DOI: 10.3389/fcell.2016.00042] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 04/25/2016] [Indexed: 02/03/2023] Open
Abstract
Trafficking in eukaryotic cells is a tightly regulated process to ensure correct cargo delivery to the proper destination organelle or plasma membrane. In this review, we focus on how the vesicle fusion machinery, the SNARE complex, is regulated by the interplay of the multisubunit tethering complexes (MTC) with the SNAREs and Sec1/Munc18 (SM) proteins. Although these factors are used in different stages of membrane trafficking, e.g., Golgi to plasma membrane transport vs. vacuolar fusion, and in a variety of diverse eukaryotic cell types, many commonalities between their functions are being revealed. We explore the various protein-protein interactions and findings from functional reconstitution studies in order to highlight both their common features and the differences in their modes of regulation. These studies serve as a starting point for mechanistic explorations in other systems.
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Affiliation(s)
- Michelle L Dubuke
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School Worcester, MA USA
| | - Mary Munson
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School Worcester, MA USA
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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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Abstract
Secretion is the cellular process present in every organism that delivers soluble proteins and cargoes to the extracellular space. In eukaryotes, conventional protein secretion (CPS) is the trafficking route that secretory proteins undertake when are transported from the endoplasmic reticulum (ER) to the Golgi apparatus (GA), and subsequently to the plasma membrane (PM) via secretory vesicles or secretory granules. This book chapter recalls the fundamental steps in cell biology research contributing to the elucidation of CPS; it describes the most prominent examples of conventionally secreted proteins in eukaryotic cells and the molecular mechanisms necessary to regulate each step of this process.
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Milev MP, Hasaj B, Saint-Dic D, Snounou S, Zhao Q, Sacher M. TRAMM/TrappC12 plays a role in chromosome congression, kinetochore stability, and CENP-E recruitment. ACTA ACUST UNITED AC 2015; 209:221-34. [PMID: 25918224 PMCID: PMC4411272 DOI: 10.1083/jcb.201501090] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The TRAPP subunit TrappC12/TTC15, here renamed TRAMM, plays a role in the regulation of kinetochore stability and CENP-E recruitment during mitosis. Chromosome congression requires the stable attachment of microtubules to chromosomes mediated by the kinetochore, a large proteinaceous structure whose mechanism of assembly is unknown. In this paper, we present the finding that a protein called TRAMM (formerly known as TrappC12) plays a role in mitosis. Depletion of TRAMM resulted in noncongressed chromosomes and arrested cells in mitosis. Small amounts of TRAMM associated with chromosomes, and its depletion affected the localization of some kinetochore proteins, the strongest effect being seen for CENP-E. TRAMM interacts with CENP-E, and depletion of TRAMM prevented the recruitment of CENP-E to the kinetochore. TRAMM is phosphorylated early in mitosis and dephosphorylated at the onset of anaphase. Interestingly, this phosphorylation/dephosphorylation cycle correlates with its association/disassociation with CENP-E. Finally, we demonstrate that a phosphomimetic form of TRAMM recruited CENP-E to kinetochores more efficiently than did the nonphosphorylatable mutant. Our study identifies a moonlighting function for TRAMM during mitosis and adds a new component that regulates kinetochore stability and CENP-E recruitment.
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Affiliation(s)
- Miroslav P Milev
- Department of Biology, Concordia University, Montreal, Quebec H4B 1R6, Canada
| | - Benedeta Hasaj
- Department of Biology, Concordia University, Montreal, Quebec H4B 1R6, Canada
| | - Djenann Saint-Dic
- Department of Biology, Concordia University, Montreal, Quebec H4B 1R6, Canada
| | - Sary Snounou
- Department of Biology, Concordia University, Montreal, Quebec H4B 1R6, Canada
| | - Qingchuan Zhao
- Department of Biology, Concordia University, Montreal, Quebec H4B 1R6, Canada
| | - Michael Sacher
- Department of Biology, Concordia University, Montreal, Quebec H4B 1R6, Canada Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec H3A 0C7, Canada
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Hierro A, Gershlick DC, Rojas AL, Bonifacino JS. Formation of Tubulovesicular Carriers from Endosomes and Their Fusion to the trans-Golgi Network. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2015; 318:159-202. [PMID: 26315886 DOI: 10.1016/bs.ircmb.2015.05.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Endosomes undergo extensive spatiotemporal rearrangements as proteins and lipids flux through them in a series of fusion and fission events. These controlled changes enable the concentration of cargo for eventual degradation while ensuring the proper recycling of other components. A growing body of studies has now defined multiple recycling pathways from endosomes to the trans-Golgi network (TGN) which differ in their molecular machineries. The recycling process requires specific sets of lipids, coats, adaptors, and accessory proteins that coordinate cargo selection with membrane deformation and its association with the cytoskeleton. Specific tethering factors and SNARE (SNAP (Soluble NSF Attachment Protein) Receptor) complexes are then required for the docking and fusion with the acceptor membrane. Herein, we summarize some of the current knowledge of the machineries that govern the retrograde transport from endosomes to the TGN.
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Affiliation(s)
- Aitor Hierro
- Structural Biology Unit, CIC bioGUNE, Derio, Spain; IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
| | - David C Gershlick
- Cell Biology and Metabolism Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | | | - Juan S Bonifacino
- Cell Biology and Metabolism Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
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Fajardo-Somera RA, Jöhnk B, Bayram Ö, Valerius O, Braus GH, Riquelme M. Dissecting the function of the different chitin synthases in vegetative growth and sexual development in Neurospora crassa. Fungal Genet Biol 2015; 75:30-45. [DOI: 10.1016/j.fgb.2015.01.002] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Revised: 12/17/2014] [Accepted: 01/07/2015] [Indexed: 01/22/2023]
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50
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Sanchez-Wandelmer J, Ktistakis NT, Reggiori F. ERES: sites for autophagosome biogenesis and maturation? J Cell Sci 2015; 128:185-92. [PMID: 25568152 DOI: 10.1242/jcs.158758] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2023] Open
Abstract
Autophagosomes are the hallmark of autophagy, but despite their central role in this degradative pathway that involves vesicle transport to lysosomes or vacuoles, the mechanism underlying their biogenesis still remains largely unknown. Our current concepts about autophagosome biogenesis are based on models suggesting that a small autonomous cisterna grows into an autophagosome through expansion at its extremities. Recent findings have revealed that endoplasmic reticulum (ER) exit sites (ERES), specialized ER regions where proteins are sorted into the secretory system, are key players in the formation of autophagosomes. Owing to the morphological connection of nascent autophagosomes with the ER, this has raised several questions that challenge our current perception of autophagosome biogenesis, such as are ERES the compartments where autophagosome formation takes place? What is the functional relevance of this connection? Are these compartments providing essential molecules for the generation of autophagosomes and/or are they structural platforms where these vesicles emerge? In this Hypothesis, we discuss recent data that have implicated the ERES in autophagosome biogenesis and we propose two models to describe the possible role of this compartment at different steps in the process of autophagosome biogenesis. This article is part of a Focus on Autophagosome biogenesis. For further reading, please see related articles: 'Membrane dynamics in autophagosome biogenesis' by Sven R. Carlsson and Anne Simonsen (J. Cell Sci. 128, 193-205) and 'WIPI proteins: essential PtdIns3P effectors at the nascent autophagosome' by Tassula Proikas-Cezanne et al. (J. Cell Sci. 128, 207-217).
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Affiliation(s)
- Jana Sanchez-Wandelmer
- Department of Cell Biology, Center for Molecular Medicine, University Medical Centre Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
| | | | - Fulvio Reggiori
- Department of Cell Biology, Center for Molecular Medicine, University Medical Centre Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
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