1
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Paira S, Chakraborty A, Das B. The Sequential Recruitments of Rab-GTPase Ypt1p and the NNS Complex onto pre- HAC1 mRNA Promote Its Nuclear Degradation in Baker's Yeast. Mol Cell Biol 2023; 43:371-400. [PMID: 37533322 PMCID: PMC10448977 DOI: 10.1080/10985549.2023.2227016] [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: 12/22/2022] [Revised: 06/10/2023] [Accepted: 06/12/2023] [Indexed: 08/04/2023] Open
Abstract
Induction of unfolded protein response involves activation of transcription factor Hac1p that is encoded by HAC1 pre-mRNA harboring an intron and a bipartite element (BE), which is subjected to nuclear mRNA decay by the nuclear exosome/Cbc1p-Tif4631p-dependent Exosome Targeting (CTEXT) complex. Using a combination of genetic and biochemical approaches, we demonstrate that a Rab-GTPase Ypt1p controls unfolded protein response signaling dynamics. This regulation relies on the nuclear localization of a small fraction of the cellular Ypt1p pool in the absence of endoplasmic reticulum (ER)-stress causing a strong association of the nuclear Ypt1p with pre-HAC1 mRNA that eventually promotes sequential recruitments of NNS, CTEXT, and the nuclear exosome onto this pre-mRNA. Recruitment of these decay factors onto pre-HAC1 mRNA is accompanied by its rapid nuclear decay that produces a precursor RNA pool lacking functional BE thereby causing its inefficient targeting to Ire1p foci leading to their diminished splicing and translation. ER stress triggers rapid relocalization of the nuclear pool of Ypt1p to the cytoplasm leading to its dissociation from pre-HAC1 mRNA thereby causing decreased recruitment of these decay factors to precursor HAC1 RNA leading to its diminished degradation. Reduced decay results in an increased abundance of pre-HAC1 mRNA with intact functional BE leading to its enhanced recruitment to Ire1p foci.
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Affiliation(s)
- Sunirmal Paira
- Department of Life Science and Biotechnology, Jadavpur University, Kolkata, India
| | - Anish Chakraborty
- Department of Life Science and Biotechnology, Jadavpur University, Kolkata, India
| | - Biswadip Das
- Department of Life Science and Biotechnology, Jadavpur University, Kolkata, India
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2
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Liu X, Tong M, Zhang A, Liu M, Zhao B, Liu Z, Li Z, Zhu X, Guo Y, Li R. COPII genes SEC31A/B are essential for gametogenesis and interchangeable in pollen development in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 105:1600-1614. [PMID: 33340171 DOI: 10.1111/tpj.15136] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 11/25/2020] [Accepted: 11/30/2020] [Indexed: 05/04/2023]
Abstract
In eukaryotes, coat protein complex II (COPII) vesicles mediate anterograde traffic from the endoplasmic reticulum to the Golgi apparatus. Compared to yeasts, plants have multiple COPII coat proteins; however, the functional diversity among them is less well understood. SEC31A and SEC31B are outer coat proteins found in COPII vesicles in Arabidopsis. In this study, we explored the function of SEC31A and compared it with that of SEC31B from various perspectives. SEC31A was widely expressed, but at a significantly lower level than SEC31B. SEC31A-mCherry and SEC31B-GFP exhibited a high co-localization rate in pollen, but a lower rate in growing pollen tubes. The sec31a single mutant exhibited normal growth. SEC31A expression driven by the SEC31B promoter rescued the pollen abortion and infertility observed in sec31b. A sec31asec31b double mutant was unavailable due to lethality of the sec31asec31b gametophyte. Transmission electron microscopy revealed that one quarter of male gametogenesis was arrested at the uninuclear microspore stage, while confocal laser scanning microscopy showed that 1/4 female gametophyte development was suspended at the functional megaspore stage in sec31a-1/+sec31b-3/+ plants. Our study highlights the essential role of SEC31A/B in gametogenesis and their interchangeable functions in pollen development.
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Affiliation(s)
- Xiaoyu Liu
- Hebei Key Laboratory of Molecular and Cellular Biology, College of Life Science, Hebei Normal University, Shijia Zhuang, Hebei, 050024, P.R. China
- Key Laboratory of Molecular and Cellular Biology of Ministry of Education, College of Life Science, Hebei Normal University, Shijia Zhuang, Hebei, 050024, P.R. China
- Hebei Collaboration Innovation Center for Cell Signaling, Shijia Zhuang, Hebei, 050024, P.R. China
| | - Mengjuan Tong
- Hebei Key Laboratory of Molecular and Cellular Biology, College of Life Science, Hebei Normal University, Shijia Zhuang, Hebei, 050024, P.R. China
- Key Laboratory of Molecular and Cellular Biology of Ministry of Education, College of Life Science, Hebei Normal University, Shijia Zhuang, Hebei, 050024, P.R. China
- Hebei Collaboration Innovation Center for Cell Signaling, Shijia Zhuang, Hebei, 050024, P.R. China
| | - Aiwei Zhang
- Hebei Key Laboratory of Molecular and Cellular Biology, College of Life Science, Hebei Normal University, Shijia Zhuang, Hebei, 050024, P.R. China
- Key Laboratory of Molecular and Cellular Biology of Ministry of Education, College of Life Science, Hebei Normal University, Shijia Zhuang, Hebei, 050024, P.R. China
- Hebei Collaboration Innovation Center for Cell Signaling, Shijia Zhuang, Hebei, 050024, P.R. China
| | - Mei Liu
- Hebei Key Laboratory of Molecular and Cellular Biology, College of Life Science, Hebei Normal University, Shijia Zhuang, Hebei, 050024, P.R. China
- Key Laboratory of Molecular and Cellular Biology of Ministry of Education, College of Life Science, Hebei Normal University, Shijia Zhuang, Hebei, 050024, P.R. China
- Hebei Collaboration Innovation Center for Cell Signaling, Shijia Zhuang, Hebei, 050024, P.R. China
| | - Bingchun Zhao
- Hebei Key Laboratory of Molecular and Cellular Biology, College of Life Science, Hebei Normal University, Shijia Zhuang, Hebei, 050024, P.R. China
- Key Laboratory of Molecular and Cellular Biology of Ministry of Education, College of Life Science, Hebei Normal University, Shijia Zhuang, Hebei, 050024, P.R. China
- Hebei Collaboration Innovation Center for Cell Signaling, Shijia Zhuang, Hebei, 050024, P.R. China
| | - Zhaojiao Liu
- Hebei Key Laboratory of Molecular and Cellular Biology, College of Life Science, Hebei Normal University, Shijia Zhuang, Hebei, 050024, P.R. China
- Key Laboratory of Molecular and Cellular Biology of Ministry of Education, College of Life Science, Hebei Normal University, Shijia Zhuang, Hebei, 050024, P.R. China
- Hebei Collaboration Innovation Center for Cell Signaling, Shijia Zhuang, Hebei, 050024, P.R. China
| | - Zhouyue Li
- Hebei Key Laboratory of Molecular and Cellular Biology, College of Life Science, Hebei Normal University, Shijia Zhuang, Hebei, 050024, P.R. China
- Key Laboratory of Molecular and Cellular Biology of Ministry of Education, College of Life Science, Hebei Normal University, Shijia Zhuang, Hebei, 050024, P.R. China
- Hebei Collaboration Innovation Center for Cell Signaling, Shijia Zhuang, Hebei, 050024, P.R. China
| | - Xu Zhu
- Hebei Key Laboratory of Molecular and Cellular Biology, College of Life Science, Hebei Normal University, Shijia Zhuang, Hebei, 050024, P.R. China
- Key Laboratory of Molecular and Cellular Biology of Ministry of Education, College of Life Science, Hebei Normal University, Shijia Zhuang, Hebei, 050024, P.R. China
- Hebei Collaboration Innovation Center for Cell Signaling, Shijia Zhuang, Hebei, 050024, P.R. China
| | - Yi Guo
- Hebei Key Laboratory of Molecular and Cellular Biology, College of Life Science, Hebei Normal University, Shijia Zhuang, Hebei, 050024, P.R. China
- Key Laboratory of Molecular and Cellular Biology of Ministry of Education, College of Life Science, Hebei Normal University, Shijia Zhuang, Hebei, 050024, P.R. China
- Hebei Collaboration Innovation Center for Cell Signaling, Shijia Zhuang, Hebei, 050024, P.R. China
| | - Rui Li
- Hebei Key Laboratory of Molecular and Cellular Biology, College of Life Science, Hebei Normal University, Shijia Zhuang, Hebei, 050024, P.R. China
- Key Laboratory of Molecular and Cellular Biology of Ministry of Education, College of Life Science, Hebei Normal University, Shijia Zhuang, Hebei, 050024, P.R. China
- Hebei Collaboration Innovation Center for Cell Signaling, Shijia Zhuang, Hebei, 050024, P.R. China
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3
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The Close Relationship between the Golgi Trafficking Machinery and Protein Glycosylation. Cells 2020; 9:cells9122652. [PMID: 33321764 PMCID: PMC7764369 DOI: 10.3390/cells9122652] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 12/04/2020] [Accepted: 12/07/2020] [Indexed: 12/12/2022] Open
Abstract
Glycosylation is the most common post-translational modification of proteins; it mediates their correct folding and stability, as well as their transport through the secretory transport. Changes in N- and O-linked glycans have been associated with multiple pathological conditions including congenital disorders of glycosylation, inflammatory diseases and cancer. Glycoprotein glycosylation at the Golgi involves the coordinated action of hundreds of glycosyltransferases and glycosidases, which are maintained at the correct location through retrograde vesicle trafficking between Golgi cisternae. In this review, we describe the molecular machinery involved in vesicle trafficking and tethering at the Golgi apparatus and the effects of mutations in the context of glycan biosynthesis and human diseases.
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4
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D'Souza Z, Taher FS, Lupashin VV. Golgi inCOGnito: From vesicle tethering to human disease. Biochim Biophys Acta Gen Subj 2020; 1864:129694. [PMID: 32730773 PMCID: PMC7384418 DOI: 10.1016/j.bbagen.2020.129694] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 07/21/2020] [Accepted: 07/23/2020] [Indexed: 12/11/2022]
Abstract
The Conserved Oligomeric Golgi (COG) complex, a multi-subunit vesicle tethering complex of the CATCHR (Complexes Associated with Tethering Containing Helical Rods) family, controls several aspects of cellular homeostasis by orchestrating retrograde vesicle traffic within the Golgi. The COG complex interacts with all key players regulating intra-Golgi trafficking, namely SNAREs, SNARE-interacting proteins, Rabs, coiled-coil tethers, and vesicular coats. In cells, COG deficiencies result in the accumulation of non-tethered COG-complex dependent (CCD) vesicles, dramatic morphological and functional abnormalities of the Golgi and endosomes, severe defects in N- and O- glycosylation, Golgi retrograde trafficking, sorting and protein secretion. In humans, COG mutations lead to severe multi-systemic diseases known as COG-Congenital Disorders of Glycosylation (COG-CDG). In this report, we review the current knowledge of the COG complex and analyze COG-related trafficking and glycosylation defects in COG-CDG patients.
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Affiliation(s)
- Zinia D'Souza
- Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Farhana S Taher
- Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Vladimir V Lupashin
- Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, AR, USA.
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5
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Wang Q, Zhong C, Xiao H. Genetic Engineering of Filamentous Fungi for Efficient Protein Expression and Secretion. Front Bioeng Biotechnol 2020; 8:293. [PMID: 32322579 PMCID: PMC7156587 DOI: 10.3389/fbioe.2020.00293] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 03/19/2020] [Indexed: 02/05/2023] Open
Abstract
Filamentous fungi are considered as unique cell factories for protein production due to the high efficiency of protein secretion and superior capability of post-translational modifications. In this review, we firstly introduce the secretory pathway in filamentous fungi. We next summarize the current state-of-the-art works regarding how various genetic engineering strategies are applied for enhancing protein expression and secretion in filamentous fungi. Finally, in a future perspective, we discuss the great potential of genome engineering for further improving protein expression and secretion in filamentous fungi.
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Affiliation(s)
- Qin Wang
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, and Laboratory of Molecular Biochemical Engineering, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Chao Zhong
- Materials and Physical Biology Division, School of Physical Science and Technology, ShanghaiTech University, Shanghai, China
- Materials Synthetic Biology Center, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Han Xiao
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, and Laboratory of Molecular Biochemical Engineering, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
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6
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Lawaju BR, Niraula P, Lawrence GW, Lawrence KS, Klink VP. The Glycine max Conserved Oligomeric Golgi (COG) Complex Functions During a Defense Response to Heterodera glycines. FRONTIERS IN PLANT SCIENCE 2020; 11:564495. [PMID: 33262774 PMCID: PMC7686354 DOI: 10.3389/fpls.2020.564495] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 10/02/2020] [Indexed: 05/07/2023]
Abstract
The conserved oligomeric Golgi (COG) complex, functioning in retrograde trafficking, is a universal structure present among eukaryotes that maintains the correct Golgi structure and function. The COG complex is composed of eight subunits coalescing into two sub-complexes. COGs1-4 compose Sub-complex A. COGs5-8 compose Sub-complex B. The observation that COG interacts with the syntaxins, suppressors of the erd2-deletion 5 (Sed5p), is noteworthy because Sed5p also interacts with Sec17p [alpha soluble NSF attachment protein (α-SNAP)]. The α-SNAP gene is located within the major Heterodera glycines [soybean cyst nematode (SCN)] resistance locus (rhg1) and functions in resistance. The study presented here provides a functional analysis of the Glycine max COG complex. The analysis has identified two paralogs of each COG gene. Functional transgenic studies demonstrate at least one paralog of each COG gene family functions in G. max during H. glycines resistance. Furthermore, treatment of G. max with the bacterial effector harpin, known to function in effector triggered immunity (ETI), leads to the induced transcription of at least one member of each COG gene family that has a role in H. glycines resistance. In some instances, altered COG gene expression changes the relative transcript abundance of syntaxin 31. These results indicate that the G. max COG complex functions through processes involving ETI leading to H. glycines resistance.
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Affiliation(s)
- Bisho Ram Lawaju
- Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology, Mississippi State University, Starkville, MS, United States
| | - Prakash Niraula
- Department of Biological Sciences, Mississippi State University, Starkville, MS, United States
| | - Gary W. Lawrence
- Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology, Mississippi State University, Starkville, MS, United States
| | - Kathy S. Lawrence
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL, United States
| | - Vincent P. Klink
- Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology, Mississippi State University, Starkville, MS, United States
- Department of Biological Sciences, Mississippi State University, Starkville, MS, United States
- Center for Computational Sciences High Performance Computing Collaboratory, Mississippi State University, Starkville, MS, United States
- *Correspondence: Vincent P. Klink, ;
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7
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Blackburn JB, D'Souza Z, Lupashin VV. Maintaining order: COG complex controls Golgi trafficking, processing, and sorting. FEBS Lett 2019; 593:2466-2487. [PMID: 31381138 PMCID: PMC6771879 DOI: 10.1002/1873-3468.13570] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Revised: 07/31/2019] [Accepted: 08/01/2019] [Indexed: 12/31/2022]
Abstract
The conserved oligomeric Golgi (COG) complex, a multisubunit tethering complex of the CATCHR (complexes associated with tethering containing helical rods) family, controls membrane trafficking and ensures Golgi homeostasis by orchestrating retrograde vesicle targeting within the Golgi. In humans, COG defects lead to severe multisystemic diseases known as COG-congenital disorders of glycosylation (COG-CDG). The COG complex both physically and functionally interacts with all classes of molecules maintaining intra-Golgi trafficking, namely SNAREs, SNARE-interacting proteins, Rabs, coiled-coil tethers, and vesicular coats. Here, we review our current knowledge of COG-related trafficking and glycosylation defects in humans and model organisms, and analyze possible scenarios for the molecular mechanism of the COG orchestrated vesicle targeting.
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Affiliation(s)
- Jessica B. Blackburn
- Department of Physiology and BiophysicsUniversity of Arkansas for Medical SciencesLittle RockARUSA
- Present address:
Division of Allergy, Pulmonary and Critical Care MedicineDepartment of MedicineVanderbilt University Medical CenterNashvilleTNUSA
| | - Zinia D'Souza
- Department of Physiology and BiophysicsUniversity of Arkansas for Medical SciencesLittle RockARUSA
| | - Vladimir V. Lupashin
- Department of Physiology and BiophysicsUniversity of Arkansas for Medical SciencesLittle RockARUSA
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8
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Boppidi KR, Ribeiro LFC, Iambamrung S, Nelson SM, Wang Y, Momany M, Richardson EA, Lincoln S, Srivastava R, Harris SD, Marten MR. Altered secretion patterns and cell wall organization caused by loss of PodB function in the filamentous fungus Aspergillus nidulans. Sci Rep 2018; 8:11433. [PMID: 30061727 PMCID: PMC6065416 DOI: 10.1038/s41598-018-29615-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 07/12/2018] [Indexed: 12/27/2022] Open
Abstract
Filamentous fungi are widely used in the production of a variety of industrially relevant enzymes and proteins as they have the unique ability to secrete tremendous amounts of proteins. However, the secretory pathways in filamentous fungi are not completely understood. Here, we investigated the role of a mutation in the POlarity Defective (podB) gene on growth, protein secretion, and cell wall organization in Aspergillus nidulans using a temperature sensitive (Ts) mutant. At restrictive temperature, the mutation resulted in lack of biomass accumulation, but led to a significant increase in specific protein productivity. Proteomic analysis of the secretome showed that the relative abundance of 584 (out of 747 identified) proteins was altered due to the mutation. Of these, 517 were secreted at higher levels. Other phenotypic differences observed in the mutant include up-regulation of unfolded protein response (UPR), deformation of Golgi apparatus and uneven cell wall thickness. Furthermore, proteomic analysis of cell wall components in the mutant revealed the presence of intracellular proteins in higher abundance accompanied by lower levels of most cell wall proteins. Taken together, results from this study suggest the importance of PodB as a target when engineering fungal strains for enhanced secretion of valuable biomolecules.
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Affiliation(s)
- Karthik R Boppidi
- University of Maryland - Baltimore County, Department of Chemical Biochemical and Environmental Engineering, Baltimore, MD, USA
| | - Liliane Fraga Costa Ribeiro
- University of Maryland - Baltimore County, Department of Chemical Biochemical and Environmental Engineering, Baltimore, MD, USA
| | - Sirasa Iambamrung
- University of Maryland - Baltimore County, Department of Chemical Biochemical and Environmental Engineering, Baltimore, MD, USA
| | - Sidney M Nelson
- University of Maryland - Baltimore County, Department of Chemical Biochemical and Environmental Engineering, Baltimore, MD, USA
| | - Yan Wang
- University of Maryland - College Park, Department of Cell Biology and Molecular Genetics, College Park, MD, USA
| | - Michelle Momany
- University of Georgia, Fungal Biology Group and Department of Plant Biology, Athens, GA, USA
| | | | - Stephen Lincoln
- University of Connecticut, Department of Chemical and Biomolecular Engineering, Storrs, CT, USA
| | - Ranjan Srivastava
- University of Connecticut, Department of Chemical and Biomolecular Engineering, Storrs, CT, USA
| | - Steven D Harris
- University of Manitoba, Department of Biological Sciences, Winnipeg, MB, Canada
| | - Mark R Marten
- University of Maryland - Baltimore County, Department of Chemical Biochemical and Environmental Engineering, Baltimore, MD, USA.
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9
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Ishii M, Lupashin VV, Nakano A. Detailed Analysis of the Interaction of Yeast COG Complex. Cell Struct Funct 2018; 43:119-127. [PMID: 29899178 DOI: 10.1247/csf.18014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The Golgi apparatus is a central station for protein trafficking in eukaryotic cells. A widely accepted model of protein transport within the Golgi apparatus is cisternal maturation. Each cisterna has specific resident proteins, which are thought to be maintained by COPI-mediated transport. However, the mechanisms underlying specific sorting of these Golgi-resident proteins remain elusive. To obtain a clue to understand the selective sorting of vesicles between the Golgi cisterenae, we investigated the molecular arrangements of the conserved oligomeric Golgi (COG) subunits in yeast cells. Mutations in COG subunits cause defects in Golgi trafficking and glycosylation of proteins and are causative of Congenital Disorders of Glycosylation (CDG) in humans. Interactions among COG subunits in cytosolic and membrane fractions were investigated by co-immunoprecipitation. Cytosolic COG subunits existed as octamers, whereas membrane-associated COG subunits formed a variety of subcomplexes. Relocation of individual COG subunits to mitochondria resulted in recruitment of only a limited number of other COG subunits to mitochondria. These results indicate that COG proteins function in the forms of a variety of subcomplexes and suggest that the COG complex does not comprise stable tethering without other interactors.Key words: The Golgi apparatus, COG complex, yeast, membrane trafficking, multi-subunit tethering complex.
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Affiliation(s)
- Midori Ishii
- Live Cell Super-Resolution Imaging Research Team, RIKEN Center for Advanced Photonics.,Department of Biological Sciences, Graduate School of Science, The University of Tokyo
| | - Vladimir V Lupashin
- Department of Physiology and Biophysics, University of Arkansas for Medical Sciences
| | - Akihiko Nakano
- Live Cell Super-Resolution Imaging Research Team, RIKEN Center for Advanced Photonics.,Department of Biological Sciences, Graduate School of Science, The University of Tokyo
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10
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Haijes HA, Jaeken J, Foulquier F, van Hasselt PM. Hypothesis: lobe A (COG1–4)-CDG causes a more severe phenotype than lobe B (COG5–8)-CDG. J Med Genet 2017; 55:137-142. [DOI: 10.1136/jmedgenet-2017-104586] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Revised: 06/07/2017] [Accepted: 06/21/2017] [Indexed: 01/26/2023]
Abstract
The conserved oligomeric Golgi (COG) complex consists of eight subunits organized in two lobes: lobe A (COG1–4) and lobe B (COG5–8). The different functional roles of COG lobe A and lobe B might result in distinct clinical phenotypes in patients with COG-CDG (congenital disorders of glycosylation). This hypothesis is supported by three observations. First, knock-down of COG lobe A components affects Golgi morphology more severely than knock-down of COG lobe B components. Second, nearly all of the 27 patients with lobe B COG-CDG had bi-allelic truncating mutations, as compared with only one of the six patients with lobe A COG-CDG. This represents a frequency gap which suggests that bi-allelic truncating mutations in COG lobe A genes might be non-viable. Third, in support, large-scale exome data of healthy adults (Exome Aggregation Consortium (ExAC)) underline that COG lobe A genes are less tolerant to genetic variation than COG lobe B genes. Thus, comparable molecular defects are more detrimental in lobe A COG-CDG than in lobe B COG-CDG. In a larger perspective, clinical phenotypic severity corresponded nicely with tolerance to genetic variation. Therefore, genomic epidemiology can potentially be used as a photographic negative for mutational severity.
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11
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Anderson NS, Mukherjee I, Bentivoglio CM, Barlowe C. The Golgin protein Coy1 functions in intra-Golgi retrograde transport and interacts with the COG complex and Golgi SNAREs. Mol Biol Cell 2017; 28:mbc.E17-03-0137. [PMID: 28794270 PMCID: PMC5620376 DOI: 10.1091/mbc.e17-03-0137] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Revised: 07/12/2017] [Accepted: 07/31/2017] [Indexed: 01/09/2023] Open
Abstract
Extended coiled-coil proteins of the Golgin family play prominent roles in maintaining the structure and function of the Golgi complex. Here we further investigate the Golgin protein Coy1 and document its function in retrograde transport between early Golgi compartments. Cells that lack Coy1 displayed a reduced half-life of the Och1 mannosyltransferase, an established cargo of intra-Golgi retrograde transport. Combining the coy1Δ mutation with deletions in other putative retrograde Golgins (sgm1Δ and rud3Δ) caused strong glycosylation and growth defects and reduced membrane association of the Conserved Oligomeric Golgi complex. In contrast, overexpression of COY1 inhibited the growth of mutant strains deficient in fusion activity at the Golgi (sed5-1 and sly1-ts). To map Coy1 protein interactions, co-immunoprecipitation experiments revealed an association with the Conserved Oliogmeric Golgi (COG) complex and with intra-Golgi SNARE proteins. These physical interactions are direct, as Coy1 was efficiently captured in vitro by Lobe A of the COG complex and the purified SNARE proteins Gos1, Sed5 and Sft1. Thus, our genetic, in vivo, and biochemical data indicate a role for Coy1 in regulating COG complex-dependent fusion of retrograde-directed COPI vesicles.
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Affiliation(s)
- Nadine S Anderson
- Department of Biochemistry & Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755
| | - Indrani Mukherjee
- Department of Biochemistry & Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755
| | - Christine M Bentivoglio
- Department of Biochemistry & Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755
| | - Charles Barlowe
- Department of Biochemistry & Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755
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12
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Klink VP, Sharma K, Pant SR, McNeece B, Niraula P, Lawrence GW. Components of the SNARE-containing regulon are co-regulated in root cells undergoing defense. PLANT SIGNALING & BEHAVIOR 2017; 12:e1274481. [PMID: 28010187 PMCID: PMC5351740 DOI: 10.1080/15592324.2016.1274481] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Revised: 12/14/2016] [Accepted: 12/15/2016] [Indexed: 05/23/2023]
Abstract
The term regulon has been coined in the genetic model plant Arabidopsis thaliana, denoting a structural and physiological defense apparatus defined genetically through the identification of the penetration (pen) mutants. The regulon is composed partially by the soluble N-ethylmaleimide-sensitive fusion protein attachment protein receptor (SNARE) syntaxin PEN1. PEN1 has homology to a Saccharomyces cerevisae gene that regulates a Secretion (Sec) protein, Suppressor of Sec 1 (Sso1p). The regulon is also composed of the β-glucosidase (PEN2) and an ATP binding cassette (ABC) transporter (PEN3). While important in inhibiting pathogen infection, limited observations have been made regarding the transcriptional regulation of regulon genes until now. Experiments made using the model agricultural Glycine max (soybean) have identified co-regulated gene expression of regulon components. The results explain the observation of hundreds of genes expressed specifically in the root cells undergoing the natural process of defense. Data regarding additional G. max genes functioning within the context of the regulon are presented here, including Sec 14, Sec 4 and Sec 23. Other examined G. max homologs of membrane fusion genes include an endosomal bromo domain-containing protein1 (Bro1), syntaxin6 (SYP6), SYP131, SYP71, SYP8, Bet1, coatomer epsilon (ϵ-COP), a coatomer zeta (ζ-COP) paralog and an ER to Golgi component (ERGIC) protein. Furthermore, the effectiveness of biochemical pathways that would function within the context of the regulon ave been examined, including xyloglucan xylosyltransferase (XXT), reticuline oxidase (RO) and galactinol synthase (GS). The experiments have unveiled the importance of the regulon during defense in the root and show how the deposition of callose relates to the process.
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Affiliation(s)
- Vincent P. Klink
- Department of Biological Sciences, Mississippi State University, Mississippi State, MS, USA
| | - Keshav Sharma
- Department of Biological Sciences, Mississippi State University, Mississippi State, MS, USA
| | - Shankar R. Pant
- Department of Biological Sciences, Mississippi State University, Mississippi State, MS, USA
| | - Brant McNeece
- Department of Biological Sciences, Mississippi State University, Mississippi State, MS, USA
| | - Prakash Niraula
- Department of Biological Sciences, Mississippi State University, Mississippi State, MS, USA
| | - Gary W. Lawrence
- Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology, Mississippi State University, Mississippi State, MS, USA
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13
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Zhao B, Shi H, Wang W, Liu X, Gao H, Wang X, Zhang Y, Yang M, Li R, Guo Y. Secretory COPII Protein SEC31B Is Required for Pollen Wall Development. PLANT PHYSIOLOGY 2016; 172:1625-1642. [PMID: 27634427 PMCID: PMC5100771 DOI: 10.1104/pp.16.00967] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 09/13/2016] [Indexed: 05/03/2023]
Abstract
The pollen wall protects pollen grains from abiotic and biotic stresses. During pollen wall development, tapetal cells play a vital role by secreting proteins, signals, and pollen wall material to ensure microspore development. But the regulatory mechanism underlying the secretory pathway of the tapetum is largely unknown. Here, we characterize the essential role of the Arabidopsis (Arabidopsis thaliana) COPII protein SECRETORY31B (SEC31B) in pollen wall development and the secretory activity of tapetal cells. The sporophyte-controlled atsec31b mutant exhibits severe pollen and seed abortion. Transmission electron microscopy observation indicates that pollen exine formation in the atsec31b mutant is disrupted significantly. AtSEC31B is a functional COPII protein revealed by endoplasmic reticulum (ER) exit site localization, interaction with AtSEC13A, and retarded ER-Golgi protein trafficking in the atsec31b mutant. A genetic tapetum-specific rescue assay indicates that AtSEC31B functions primarily in the tapetum. Moreover, deletion of AtSEC31B interrupted the formation of the ER-derived tapetosome and altered the location of the ATP-BINDING CASSETTE TRANSPORTER9 protein in the tapetum. Therefore, this work demonstrates that AtSEC31B plays a vital role in pollen wall development by regulating the secretory pathway of the tapetal cells.
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Affiliation(s)
- Bingchun Zhao
- Hebei Key Laboratory of Molecular and Cellular Biology and Key Laboratory of Molecular and Cellular Biology of the Ministry of Education, College of Life Science, Hebei Normal University, Shijia Zhuang 050024, People's Republic of China; and
- Hebei Collaboration Innovation Center for Cell Signaling, Shijia Zhuang 050024, People's Republic of China
| | - Haidan Shi
- Hebei Key Laboratory of Molecular and Cellular Biology and Key Laboratory of Molecular and Cellular Biology of the Ministry of Education, College of Life Science, Hebei Normal University, Shijia Zhuang 050024, People's Republic of China; and
- Hebei Collaboration Innovation Center for Cell Signaling, Shijia Zhuang 050024, People's Republic of China
| | - Wanlei Wang
- Hebei Key Laboratory of Molecular and Cellular Biology and Key Laboratory of Molecular and Cellular Biology of the Ministry of Education, College of Life Science, Hebei Normal University, Shijia Zhuang 050024, People's Republic of China; and
- Hebei Collaboration Innovation Center for Cell Signaling, Shijia Zhuang 050024, People's Republic of China
| | - Xiaoyu Liu
- Hebei Key Laboratory of Molecular and Cellular Biology and Key Laboratory of Molecular and Cellular Biology of the Ministry of Education, College of Life Science, Hebei Normal University, Shijia Zhuang 050024, People's Republic of China; and
- Hebei Collaboration Innovation Center for Cell Signaling, Shijia Zhuang 050024, People's Republic of China
| | - Hui Gao
- Hebei Key Laboratory of Molecular and Cellular Biology and Key Laboratory of Molecular and Cellular Biology of the Ministry of Education, College of Life Science, Hebei Normal University, Shijia Zhuang 050024, People's Republic of China; and
- Hebei Collaboration Innovation Center for Cell Signaling, Shijia Zhuang 050024, People's Republic of China
| | - Xiaoxiao Wang
- Hebei Key Laboratory of Molecular and Cellular Biology and Key Laboratory of Molecular and Cellular Biology of the Ministry of Education, College of Life Science, Hebei Normal University, Shijia Zhuang 050024, People's Republic of China; and
- Hebei Collaboration Innovation Center for Cell Signaling, Shijia Zhuang 050024, People's Republic of China
| | - Yinghui Zhang
- Hebei Key Laboratory of Molecular and Cellular Biology and Key Laboratory of Molecular and Cellular Biology of the Ministry of Education, College of Life Science, Hebei Normal University, Shijia Zhuang 050024, People's Republic of China; and
- Hebei Collaboration Innovation Center for Cell Signaling, Shijia Zhuang 050024, People's Republic of China
| | - Meidi Yang
- Hebei Key Laboratory of Molecular and Cellular Biology and Key Laboratory of Molecular and Cellular Biology of the Ministry of Education, College of Life Science, Hebei Normal University, Shijia Zhuang 050024, People's Republic of China; and
- Hebei Collaboration Innovation Center for Cell Signaling, Shijia Zhuang 050024, People's Republic of China
| | - Rui Li
- Hebei Key Laboratory of Molecular and Cellular Biology and Key Laboratory of Molecular and Cellular Biology of the Ministry of Education, College of Life Science, Hebei Normal University, Shijia Zhuang 050024, People's Republic of China; and
- Hebei Collaboration Innovation Center for Cell Signaling, Shijia Zhuang 050024, People's Republic of China
| | - Yi Guo
- Hebei Key Laboratory of Molecular and Cellular Biology and Key Laboratory of Molecular and Cellular Biology of the Ministry of Education, College of Life Science, Hebei Normal University, Shijia Zhuang 050024, People's Republic of China; and
- Hebei Collaboration Innovation Center for Cell Signaling, Shijia Zhuang 050024, People's Republic of China
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14
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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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15
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Suckling RJ, Poon PP, Travis SM, Majoul IV, Hughson FM, Evans PR, Duden R, Owen DJ. Structural basis for the binding of tryptophan-based motifs by δ-COP. Proc Natl Acad Sci U S A 2015; 112:14242-7. [PMID: 26578768 PMCID: PMC4655537 DOI: 10.1073/pnas.1506186112] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Coatomer consists of two subcomplexes: the membrane-targeting, ADP ribosylation factor 1 (Arf1):GTP-binding βγδζ-COP F-subcomplex, which is related to the adaptor protein (AP) clathrin adaptors, and the cargo-binding αβ'ε-COP B-subcomplex. We present the structure of the C-terminal μ-homology domain of the yeast δ-COP subunit in complex with the WxW motif from its binding partner, the endoplasmic reticulum-localized Dsl1 tether. The motif binds at a site distinct from that used by the homologous AP μ subunits to bind YxxΦ cargo motifs with its two tryptophan residues sitting in compatible pockets. We also show that the Saccharomyces cerevisiae Arf GTPase-activating protein (GAP) homolog Gcs1p uses a related WxxF motif at its extreme C terminus to bind to δ-COP at the same site in the same way. Mutations designed on the basis of the structure in conjunction with isothermal titration calorimetry confirm the mode of binding and show that mammalian δ-COP binds related tryptophan-based motifs such as that from ArfGAP1 in a similar manner. We conclude that δ-COP subunits bind Wxn(1-6)[WF] motifs within unstructured regions of proteins that influence the lifecycle of COPI-coated vesicles; this conclusion is supported by the observation that, in the context of a sensitizing domain deletion in Dsl1p, mutating the tryptophan-based motif-binding site in yeast causes defects in both growth and carboxypeptidase Y trafficking/processing.
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Affiliation(s)
- Richard J Suckling
- Medical Research Council Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom; Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, United Kingdom
| | - Pak Phi Poon
- Department of Microbiology and Immunology, Dalhousie University, Halifax, N.S., Canada B3H 4R2
| | - Sophie M Travis
- Department of Molecular Biology, Princeton University, Princeton NJ 08544
| | - Irina V Majoul
- Institute of Biology, Center for Structural and Cell Biology in Medicine, University of Lübeck, 23562 Lübeck, Germany
| | | | - Philip R Evans
- Medical Research Council Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom
| | - Rainer Duden
- Institute of Biology, Center for Structural and Cell Biology in Medicine, University of Lübeck, 23562 Lübeck, Germany
| | - David J Owen
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, United Kingdom;
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16
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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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17
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Kuhlee A, Raunser S, Ungermann C. Functional homologies in vesicle tethering. FEBS Lett 2015; 589:2487-97. [PMID: 26072291 DOI: 10.1016/j.febslet.2015.06.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Revised: 05/30/2015] [Accepted: 06/01/2015] [Indexed: 11/24/2022]
Abstract
The HOPS multisubunit tethering factor (MTC) is a macromolecular protein complex composed of six different subunits. It is one of the key components in the perception and subsequent fusion of multivesicular bodies and vacuoles. Electron microscopy studies indicate structural flexibility of the purified HOPS complex. Inducing higher rigidity into HOPS by biochemically modifying the complex declines the potential to mediate SNARE-driven membrane fusion. Thus, we propose that integral flexibility seems to be not only a feature, but of essential need for the function of HOPS. This review focuses on the general features of membrane tethering and fusion. For this purpose, we compare the structure and mode of action of different tethering factors to highlight their common central features and mechanisms.
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Affiliation(s)
- Anne Kuhlee
- Department of Structural Biochemistry, Max-Planck Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany.
| | - Stefan Raunser
- Department of Structural Biochemistry, Max-Planck Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany
| | - Christian Ungermann
- Department of Biology, University of Osnabrück, Barbarastrasse 13, 49076 Osnabrück, Germany
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18
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García-Rodríguez N, Manzano-López J, Muñoz-Bravo M, Fernández-García E, Muñiz M, Wellinger RE. Manganese redistribution by calcium-stimulated vesicle trafficking bypasses the need for P-type ATPase function. J Biol Chem 2015; 290:9335-47. [PMID: 25713143 DOI: 10.1074/jbc.m114.616334] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Indexed: 12/31/2022] Open
Abstract
Regulation of intracellular ion homeostasis is essential for eukaryotic cell physiology. An example is provided by loss of ATP2C1 function, which leads to skin ulceration, improper keratinocyte adhesion, and cancer formation in Hailey-Hailey patients. The yeast ATP2C1 orthologue PMR1 codes for a Mn(2+)/Ca(2+) transporter that is crucial for cis-Golgi manganese supply. Here, we present evidence that calcium overcomes the lack of Pmr1 through vesicle trafficking-stimulated manganese delivery and requires the endoplasmic reticulum Mn(2+) transporter Spf1 and the late endosome/trans-Golgi Nramp metal transporter Smf2. Smf2 co-localizes with the putative Mn(2+) transporter Atx2, and ATX2 overexpression counteracts the beneficial impact of calcium treatment. Our findings suggest that vesicle trafficking promotes organelle-specific ion interchange and cytoplasmic metal detoxification independent of calcineurin signaling or metal transporter re-localization. Our study identifies an alternative mode for cis-Golgi manganese supply in yeast and provides new perspectives for Hailey-Hailey disease treatment.
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Affiliation(s)
- Néstor García-Rodríguez
- From the Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Universidad de Sevilla, 41092, Sevilla, Spain and
| | - Javier Manzano-López
- the Departamento de Biolgía Celular-Instituto de Biomedicina de Sevilla (IBiS), Universidad de Sevilla, 41012 Sevilla, Spain
| | - Miguel Muñoz-Bravo
- From the Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Universidad de Sevilla, 41092, Sevilla, Spain and
| | - Elisabet Fernández-García
- From the Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Universidad de Sevilla, 41092, Sevilla, Spain and
| | - Manuel Muñiz
- the Departamento de Biolgía Celular-Instituto de Biomedicina de Sevilla (IBiS), Universidad de Sevilla, 41012 Sevilla, Spain
| | - Ralf Erik Wellinger
- From the Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Universidad de Sevilla, 41092, Sevilla, Spain and
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19
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Wang T, Grabski R, Sztul E, Hay JC. p115-SNARE interactions: a dynamic cycle of p115 binding monomeric SNARE motifs and releasing assembled bundles. Traffic 2015; 16:148-71. [PMID: 25406594 DOI: 10.1111/tra.12242] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Revised: 11/17/2014] [Accepted: 11/17/2014] [Indexed: 11/30/2022]
Abstract
Tethering factors regulate the targeting of membrane-enclosed vesicles under the control of Rab GTPases. p115, a golgin family tether, has been shown to participate in multiple stages of ER/Golgi transport. Despite extensive study, the mechanism of action of p115 is poorly understood. SNARE proteins make up the machinery for membrane fusion, and strong evidence shows that function of p115 is directly linked to its interaction with SNAREs. Using a gel filtration binding assay, we have demonstrated that in solution p115 stably interacts with ER/Golgi SNAREs rbet1 and sec22b, but not membrin and syntaxin 5. These binding preferences stemmed from selectivity of p115 for monomeric SNARE motifs as opposed to SNARE oligomers. Soluble monomeric rbet1 can compete off p115 from coat protein II (COPII) vesicles. Furthermore, excess p115 inhibits p115 function in trafficking. We conclude that monomeric SNAREs are a major binding site for p115 on COPII vesicles, and that p115 dissociates from its SNARE partners upon SNAREpin assembly. Our results suggest a model in which p115 forms a mixed p115/SNARE helix bundle with a monomeric SNARE, facilitates the binding activity and/or concentration of the SNARE at prefusion sites and is subsequently ejected as SNARE complex formation and fusion proceed.
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Affiliation(s)
- Ting Wang
- Division of Biological Sciences and Center for Structural & Functional Neuroscience, The University of Montana, Missoula, MT, USA
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20
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Gremillion SK, Harris SD, Jackson-Hayes L, Kaminskyj SGW, Loprete DM, Gauthier AC, Mercer S, Ravita AJ, Hill TW. Mutations in proteins of the Conserved Oligomeric Golgi Complex affect polarity, cell wall structure, and glycosylation in the filamentous fungus Aspergillus nidulans. Fungal Genet Biol 2014; 73:69-82. [PMID: 25312861 DOI: 10.1016/j.fgb.2014.10.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Revised: 09/30/2014] [Accepted: 10/05/2014] [Indexed: 01/18/2023]
Abstract
We have described two Aspergillus nidulans gene mutations, designated podB1 (polarity defective) and swoP1 (swollen cell), which cause temperature-sensitive defects during polarization. Mutant strains also displayed unevenness and abnormal thickness of cell walls. Un-polarized or poorly-polarized mutant cells were capable of establishing normal polarity after a shift to a permissive temperature, and mutant hyphae shifted from permissive to restrictive temperature show wall and polarity abnormalities in subsequent growth. The mutated genes (podB=AN8226.3; swoP=AN7462.3) were identified as homologues of COG2 and COG4, respectively, each predicted to encode a subunit of the multi-protein COG (Conserved Oligomeric Golgi) Complex involved in retrograde vesicle trafficking in the Golgi apparatus. Down-regulation of COG2 or COG4 resulted in abnormal polarization and cell wall staining. The GFP-tagged COG2 and COG4 homologues displayed punctate, Golgi-like localization. Lectin-blotting indicated that protein glycosylation was altered in the mutant strains compared to the wild type. A multicopy expression experiment showed evidence for functional interactions between the homologues COG2 and COG4 as well as between COG2 and COG3. To date, this work is the first regarding a functional role of the COG proteins in the development of a filamentous fungus.
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Affiliation(s)
- S K Gremillion
- Department of Biology, Armstrong State University, 11935 Abercorn Street, Savannah, GA 31419, USA.
| | - S D Harris
- Center for Plant Science Innovation, University of Nebraska, Lincoln, NE 68588-0660, USA
| | - L Jackson-Hayes
- Department of Chemistry, Rhodes College, 2000 North Parkway, Memphis, TN 38112, USA
| | - S G W Kaminskyj
- Department of Biology, University of Saskatchewan, 112 Science Place Saskatoon, Saskatchewan S7N 5E2, Canada
| | - D M Loprete
- Department of Chemistry, Rhodes College, 2000 North Parkway, Memphis, TN 38112, USA
| | - A C Gauthier
- Department of Biology, Armstrong State University, 11935 Abercorn Street, Savannah, GA 31419, USA
| | - S Mercer
- Department of Biology, Rhodes College, 2000 North Parkway, Memphis, TN 38112, USA
| | - A J Ravita
- Department of Biology, Armstrong State University, 11935 Abercorn Street, Savannah, GA 31419, USA
| | - T W Hill
- Department of Biology, Rhodes College, 2000 North Parkway, Memphis, TN 38112, USA
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21
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Target silencing of components of the conserved oligomeric Golgi complex impairs HIV-1 replication. Virus Res 2014; 192:92-102. [PMID: 25179963 DOI: 10.1016/j.virusres.2014.08.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Revised: 08/21/2014] [Accepted: 08/22/2014] [Indexed: 12/23/2022]
Abstract
All viruses require host cell factors to replicate. A large number of host factors have been identified that participate at numerous points of the human immunodeficiency virus 1 (HIV-1) life cycle. Recent evidence supports a role for components of the trans-Golgi network (TGN) in mediating early steps in the HIV-1 life cycle. The conserved oligomeric Golgi (COG) complex is a heteroctamer complex that functions in coat protein complex I (COPI)-mediated intra-Golgi retrograde trafficking and plays an important role in the maintenance of Golgi structure and integrity as well as glycosylation enzyme homeostasis. The targeted silencing of components of lobe B of the COG complex, namely COG5, COG6, COG7 and COG8, inhibited HIV-1 replication. This inhibition of HIV-1 replication preceded late reverse transcription (RT) but did not affect viral fusion. Silencing of the COG interacting protein the t-SNARE syntaxin 5, showed a similar defect in late RT product formation, strengthening the role of the TGN in HIV replication.
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22
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Ong YS, Tran THT, Gounko NV, Hong W. TMEM115 is an integral membrane protein of the Golgi complex involved in retrograde transport. J Cell Sci 2014; 127:2825-39. [PMID: 24806965 PMCID: PMC4077589 DOI: 10.1242/jcs.136754] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Searching and evaluating the Human Protein Atlas for transmembrane proteins enabled us to identify an integral membrane protein, TMEM115, that is enriched in the Golgi complex. Biochemical and cell biological analysis suggested that TMEM115 has four candidate transmembrane domains located in the N-terminal region. Both the N- and C-terminal domains are oriented towards the cytoplasm. Immunofluorescence analysis supports that TMEM115 is enriched in the Golgi cisternae. Functionally, TMEM115 knockdown or overexpression delays Brefeldin-A-induced Golgi-to-ER retrograde transport, phenocopying cells with mutations or silencing of the conserved oligomeric Golgi (COG) complex. Co-immunoprecipitation and in vitro binding experiments reveals that TMEM115 interacts with the COG complex, and might self-interact to form dimers or oligomers. A short region (residues 206–229) immediately to the C-terminal side of the fourth transmembrane domain is both necessary and sufficient for Golgi targeting. Knockdown of TMEM115 also reduces the binding of the lectins peanut agglutinin (PNA) and Helix pomatia agglutinin (HPA), suggesting an altered O-linked glycosylation profile. These results establish that TMEM115 is an integral membrane protein of the Golgi stack regulating Golgi-to-ER retrograde transport and is likely to be part of the machinery of the COG complex.
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Affiliation(s)
- Yan Shan Ong
- Institute of Molecular and Cell Biology, 61 Biopolis Drive, Singapore 138673, Singapore
| | - Ton Hoai Thi Tran
- Institute of Molecular and Cell Biology, 61 Biopolis Drive, Singapore 138673, Singapore
| | - Natalia V Gounko
- Institute of Molecular and Cell Biology, 61 Biopolis Drive, Singapore 138673, Singapore IMB-IMCB Joint Electron Microscopy Suite, 20 Biopolis Street, Singapore 138671, Singapore
| | - Wanjin Hong
- Institute of Molecular and Cell Biology, 61 Biopolis Drive, Singapore 138673, Singapore Department of Biochemistry, National University of Singapore, Singapore 117599, Singapore
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23
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De Craene JO, Courte F, Rinaldi B, Fitterer C, Herranz MC, Schmitt-Keichinger C, Ritzenthaler C, Friant S. Study of the plant COPII vesicle coat subunits by functional complementation of yeast Saccharomyces cerevisiae mutants. PLoS One 2014; 9:e90072. [PMID: 24587212 PMCID: PMC3934973 DOI: 10.1371/journal.pone.0090072] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Accepted: 01/29/2014] [Indexed: 11/29/2022] Open
Abstract
The formation and budding of endoplasmic reticulum ER-derived vesicles depends on the COPII coat protein complex that was first identified in yeast Saccharomyces cerevisiae. The ER-associated Sec12 and the Sar1 GTPase initiate the COPII coat formation by recruiting the Sec23–Sec24 heterodimer following the subsequent recruitment of the Sec13–Sec31 heterotetramer. In yeast, there is usually one gene encoding each COPII protein and these proteins are essential for yeast viability, whereas the plant genome encodes multiple isoforms of all COPII subunits. Here, we used a systematic yeast complementation assay to assess the functionality of Arabidopsis thaliana COPII proteins. In this study, the different plant COPII subunits were expressed in their corresponding temperature-sensitive yeast mutant strain to complement their thermosensitivity and secretion phenotypes. Secretion was assessed using two different yeast cargos: the soluble α-factor pheromone and the membranous v-SNARE (vesicle-soluble NSF (N-ethylmaleimide-sensitive factor) attachment protein receptor) Snc1 involved in the fusion of the secretory vesicles with the plasma membrane. This complementation study allowed the identification of functional A. thaliana COPII proteins for the Sec12, Sar1, Sec24 and Sec13 subunits that could represent an active COPII complex in plant cells. Moreover, we found that AtSec12 and AtSec23 were co-immunoprecipitated with AtSar1 in total cell extract of 15 day-old seedlings of A. thaliana. This demonstrates that AtSar1, AtSec12 and AtSec23 can form a protein complex that might represent an active COPII complex in plant cells.
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Affiliation(s)
- Johan-Owen De Craene
- Department of Molecular and Cellular Genetics, UMR7156, Université de Strasbourg and CNRS, Strasbourg, France
| | - Fanny Courte
- Department of Molecular and Cellular Genetics, UMR7156, Université de Strasbourg and CNRS, Strasbourg, France
- Institut de Biologie Moléculaire des Plantes (IBMP), UPR2357 CNRS, Université de Strasbourg, Strasbourg, France
| | - Bruno Rinaldi
- Department of Molecular and Cellular Genetics, UMR7156, Université de Strasbourg and CNRS, Strasbourg, France
| | - Chantal Fitterer
- Institut de Biologie Moléculaire des Plantes (IBMP), UPR2357 CNRS, Université de Strasbourg, Strasbourg, France
| | - Mari Carmen Herranz
- Institut de Biologie Moléculaire des Plantes (IBMP), UPR2357 CNRS, Université de Strasbourg, Strasbourg, France
| | - Corinne Schmitt-Keichinger
- Institut de Biologie Moléculaire des Plantes (IBMP), UPR2357 CNRS, Université de Strasbourg, Strasbourg, France
| | - Christophe Ritzenthaler
- Institut de Biologie Moléculaire des Plantes (IBMP), UPR2357 CNRS, Université de Strasbourg, Strasbourg, France
| | - Sylvie Friant
- Department of Molecular and Cellular Genetics, UMR7156, Université de Strasbourg and CNRS, Strasbourg, France
- * E-mail:
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24
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Semi-quantitative colony immunoassay for determining and optimizing protein expression in Saccharomyces cerevisiae and Escherichia coli. Anal Biochem 2014; 447:82-9. [DOI: 10.1016/j.ab.2013.10.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Revised: 09/21/2013] [Accepted: 10/11/2013] [Indexed: 11/20/2022]
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Abstract
The secretory pathway is responsible for the synthesis, folding, and delivery of a diverse array of cellular proteins. Secretory protein synthesis begins in the endoplasmic reticulum (ER), which is charged with the tasks of correctly integrating nascent proteins and ensuring correct post-translational modification and folding. Once ready for forward traffic, proteins are captured into ER-derived transport vesicles that form through the action of the COPII coat. COPII-coated vesicles are delivered to the early Golgi via distinct tethering and fusion machineries. Escaped ER residents and other cycling transport machinery components are returned to the ER via COPI-coated vesicles, which undergo similar tethering and fusion reactions. Ultimately, organelle structure, function, and cell homeostasis are maintained by modulating protein and lipid flux through the early secretory pathway. In the last decade, structural and mechanistic studies have added greatly to the strong foundation of yeast genetics on which this field was built. Here we discuss the key players that mediate secretory protein biogenesis and trafficking, highlighting recent advances that have deepened our understanding of the complexity of this conserved and essential process.
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26
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Willett R, Ungar D, Lupashin V. The Golgi puppet master: COG complex at center stage of membrane trafficking interactions. Histochem Cell Biol 2013; 140:271-83. [PMID: 23839779 DOI: 10.1007/s00418-013-1117-6] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/18/2013] [Indexed: 11/26/2022]
Abstract
The central organelle within the secretory pathway is the Golgi apparatus, a collection of flattened membranes organized into stacks. The cisternal maturation model of intra-Golgi transport depicts Golgi cisternae that mature from cis to medial to trans by receiving resident proteins, such as glycosylation enzymes via retrograde vesicle-mediated recycling. The conserved oligomeric Golgi (COG) complex, a multi-subunit tethering complex of the complexes associated with tethering containing helical rods family, organizes vesicle targeting during intra-Golgi retrograde transport. The COG complex, both physically and functionally, interacts with all classes of molecules maintaining intra-Golgi trafficking, namely SNAREs, SNARE-interacting proteins, Rabs, coiled-coil tethers, vesicular coats, and molecular motors. In this report, we will review the current state of the COG interactome and analyze possible scenarios for the molecular mechanism of the COG orchestrated vesicle targeting, which plays a central role in maintaining glycosylation homeostasis in all eukaryotic cells.
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Affiliation(s)
- Rose Willett
- Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, AR, USA
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27
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Delic M, Valli M, Graf AB, Pfeffer M, Mattanovich D, Gasser B. The secretory pathway: exploring yeast diversity. FEMS Microbiol Rev 2013; 37:872-914. [PMID: 23480475 DOI: 10.1111/1574-6976.12020] [Citation(s) in RCA: 140] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Revised: 02/14/2013] [Accepted: 02/17/2013] [Indexed: 12/11/2022] Open
Abstract
Protein secretion is an essential process for living organisms. In eukaryotes, this encompasses numerous steps mediated by several hundred cellular proteins. The core functions of translocation through the endoplasmic reticulum membrane, primary glycosylation, folding and quality control, and vesicle-mediated secretion are similar from yeasts to higher eukaryotes. However, recent research has revealed significant functional differences between yeasts and mammalian cells, and even among diverse yeast species. This review provides a current overview of the canonical protein secretion pathway in the model yeast Saccharomyces cerevisiae, highlighting differences to mammalian cells as well as currently unresolved questions, and provides a genomic comparison of the S. cerevisiae pathway to seven other yeast species where secretion has been investigated due to their attraction as protein production platforms, or for their relevance as pathogens. The analysis of Candida albicans, Candida glabrata, Kluyveromyces lactis, Pichia pastoris, Hansenula polymorpha, Yarrowia lipolytica, and Schizosaccharomyces pombe reveals that many - but not all - secretion steps are more redundant in S. cerevisiae due to duplicated genes, while some processes are even absent in this model yeast. Recent research obviates that even where homologous genes are present, small differences in protein sequence and/or differences in the regulation of gene expression may lead to quite different protein secretion phenotypes.
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Affiliation(s)
- Marizela Delic
- Department of Biotechnology, University of Natural Resources and Life Sciences (BOKU), Vienna, Austria; Austrian Centre of Industrial Biotechnology (ACIB GmbH), Vienna, Austria
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28
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Cottam NP, Ungar D. Retrograde vesicle transport in the Golgi. PROTOPLASMA 2012; 249:943-55. [PMID: 22160157 DOI: 10.1007/s00709-011-0361-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2011] [Accepted: 11/29/2011] [Indexed: 05/23/2023]
Abstract
The Golgi apparatus is the central sorting and biosynthesis hub of the secretory pathway, and uses vesicle transport for the recycling of its resident enzymes. This system must operate with high fidelity and efficiency for the correct modification of secretory glycoconjugates. In this review, we discuss recent advances on how coats, tethers, Rabs and SNAREs cooperate at the Golgi to achieve vesicle transport. We cover the well understood vesicle formation process orchestrated by the COPI coat, and the comprehensively documented fusion process governed by a set of Golgi localised SNAREs. Much less clear are the steps in-between formation and fusion of vesicles, and we therefore provide a much needed update of the latest findings about vesicle tethering. The interplay between Rab GTPases, golgin family coiled-coil tethers and the conserved oligomeric Golgi (COG) complex at the Golgi are thoroughly evaluated.
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Affiliation(s)
- Nathanael P Cottam
- Department of Biology (Area 9), University of York, Heslington, York, YO10 5DD, UK
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29
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Belloni G, Sechi S, Riparbelli MG, Fuller MT, Callaini G, Giansanti MG. Mutations in Cog7 affect Golgi structure, meiotic cytokinesis and sperm development during Drosophila spermatogenesis. J Cell Sci 2012; 125:5441-52. [PMID: 22946051 DOI: 10.1242/jcs.108878] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The conserved oligomeric Golgi (COG) complex plays essential roles in Golgi function, vesicle trafficking and glycosylation. Deletions in the human COG7 gene are associated with a rare multisystemic congenital disorder of glycosylation that causes mortality within the first year of life. In this paper, we characterise the Drosophila orthologue of COG7 (Cog7). Loss-of-function Cog7 mutants are viable but male sterile. The Cog7 gene product is enriched in the Golgi stacks and in Golgi-derived structures throughout spermatogenesis. Mutations in the Cog7 gene disrupt Golgi architecture and reduce the number of Golgi stacks in primary spermatocytes. During spermiogenesis, loss of the Cog7 protein impairs the assembly of the Golgi-derived acroblast in spermatids and affects axoneme architecture. Similar to the Cog5 homologue, four way stop (Fws), Cog7 enables furrow ingression during cytokinesis. We show that the recruitment of the small GTPase Rab11 and the phosphatidylinositol transfer protein Giotto (Gio) to the cleavage site requires a functioning wild-type Cog7 gene. In addition, Gio coimmunoprecipitates with Cog7 and with Rab11 in the testes. Our results altogether implicate Cog7 as an upstream component in a gio-Rab11 pathway controlling membrane addition during cytokinesis.
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Affiliation(s)
- Giorgio Belloni
- Istituto di Biologia e Patologia Molecolari del CNR, Dipartimento di Biologia e Biotecnologie Università di Roma Sapienza, P.le A Moro 5, 00185 Roma, Italy
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30
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Niu X, Gao C, Jan Lo L, Luo Y, Meng C, Hong J, Hong W, Peng J. Sec13 safeguards the integrity of the endoplasmic reticulum and organogenesis of the digestive system in zebrafish. Dev Biol 2012; 367:197-207. [PMID: 22609279 DOI: 10.1016/j.ydbio.2012.05.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2011] [Revised: 04/12/2012] [Accepted: 05/04/2012] [Indexed: 12/31/2022]
Abstract
The Sec13-Sec31 heterotetramer serves as the outer coat in the COPII complex, which mediates protein trafficking from the endoplasmic reticulum (ER) to the Golgi apparatus. Although it has been studied in depth in yeast and cultured cells, the role of COPII in organogenesis in a multicellular organism has not. We report here that a zebrafish sec13(sq198) mutant, which exhibits a phenotype of hypoplastic digestive organs, has a mutation in the sec13 gene. The mutant gene encodes a carboxyl-terminus-truncated Sec13 that loses its affinity to Sec31a, which leads to disintegration of the ER structure in various differentiated cells in sec13(sq198), including chondrocytes, intestinal epithelial cells and hepatocytes. Disruption of the ER structure activates an unfolded protein response that eventually causes the cells to undergo cell-cycle arrest and cell apoptosis, which arrest the growth of developing digestive organs in the mutant. Our data provide the first direct genetic evidence that COPII function is essential for the organogenesis of the digestive system.
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Affiliation(s)
- Xubo Niu
- Key Laboratory for Molecular Animal Nutrition, Ministry of Education, College of Animal Sciences, Zhejiang University, Hangzhou, PR China
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31
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Miller VJ, Ungar D. Re‘COG’nition at the Golgi. Traffic 2012; 13:891-7. [DOI: 10.1111/j.1600-0854.2012.01338.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Revised: 01/31/2012] [Accepted: 02/02/2012] [Indexed: 02/06/2023]
Affiliation(s)
| | - Daniel Ungar
- Department of Biology; University of York; York; UK
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32
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Jin Y, Sultana A, Gandhi P, Franklin E, Hamamoto S, Khan AR, Munson M, Schekman R, Weisman LS. Myosin V transports secretory vesicles via a Rab GTPase cascade and interaction with the exocyst complex. Dev Cell 2012; 21:1156-70. [PMID: 22172676 DOI: 10.1016/j.devcel.2011.10.009] [Citation(s) in RCA: 115] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2010] [Revised: 08/26/2011] [Accepted: 10/11/2011] [Indexed: 11/17/2022]
Abstract
Vesicle transport requires four steps: vesicle formation, movement, tethering, and fusion. In yeast, two Rab GTPases, Ypt31/32, are required for post-Golgi vesicle formation. A third Rab GTPase, Sec4, and the exocyst act in tethering and fusion of these vesicles. Vesicle production is coupled to transport via direct interaction between Ypt31/32 and the yeast myosin V, Myo2. Here we show that Myo2 interacts directly with Sec4 and the exocyst subunit Sec15. Disruption of these interactions results in compromised growth and the accumulation of secretory vesicles. We identified the Sec15-binding region on Myo2 and also identified residues on Sec15 required for interaction with Myo2. That Myo2 interacts with Sec15 uncovers additional roles for the exocyst as an adaptor for molecular motors and implies similar roles for structurally related tethering complexes. Moreover, these studies predict that for many pathways, molecular motors attach to vesicles prior to their formation and remain attached until fusion.
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Affiliation(s)
- Yui Jin
- Life Sciences Institute, Department of Cell & Developmental Biology, University of Michigan, Ann Arbor, MI 48109-2216, USA
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Laufman O, Hong W, Lev S. The COG complex interacts directly with Syntaxin 6 and positively regulates endosome-to-TGN retrograde transport. ACTA ACUST UNITED AC 2011; 194:459-72. [PMID: 21807881 PMCID: PMC3153647 DOI: 10.1083/jcb.201102045] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The conserved oligomeric Golgi (COG) complex interacts with the t-SNARE Syntaxin 6 and promotes endosome-to-TGN retrograde trafficking. The conserved oligomeric Golgi (COG) complex has been implicated in the regulation of endosome to trans-Golgi network (TGN) retrograde trafficking in both yeast and mammals. However, the exact mechanisms by which it regulates this transport route remain largely unknown. In this paper, we show that COG interacts directly with the target membrane SNARE (t-SNARE) Syntaxin 6 via the Cog6 subunit. In Cog6-depleted cells, the steady-state level of Syntaxin 6 was markedly reduced, and concomitantly, endosome-to-TGN retrograde traffic was significantly attenuated. Cog6 knockdown also affected the steady-state levels and/or subcellular distributions of Syntaxin 16, Vti1a, and VAMP4 and impaired the assembly of the Syntaxin 6–Syntaxin16–Vti1a–VAMP4 SNARE complex. Remarkably, overexpression of VAMP4, but not of Syntaxin 6, bypassed the requirement for COG and restored endosome-to-TGN trafficking in Cog6-depleted cells. These results suggest that COG directly interacts with specific t-SNAREs and positively regulates SNARE complex assembly, thereby affecting their associated trafficking steps.
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Affiliation(s)
- Orly Laufman
- Molecular Cell Biology Department, Weizmann Institute of Science, Rehovot, Israel
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34
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Reynders E, Foulquier F, Annaert W, Matthijs G. How Golgi glycosylation meets and needs trafficking: the case of the COG complex. Glycobiology 2010; 21:853-63. [PMID: 21112967 DOI: 10.1093/glycob/cwq179] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Protein glycosylation is one of the major biosynthetic functions occurring in the endoplasmic reticulum and Golgi compartments. It requires an amazing number of enzymes, chaperones, lectins and transporters whose actions delicately secure the fidelity of glycan structures. Over the past 30 years, glycobiologists hammered that glycan structures are not mere decorative elements but serve crucial cellular functions. This becomes dramatically illustrated by a group of mostly severe, inherited human disorders named congenital disorders of glycosylation (CDG). To date, many types of CDG have been defined genetically and most of the time the defects impair the biosynthesis, transfer and remodeling of N-glycans. Recently, the identification of the several types of CDG caused by deficiencies in the conserved oligomeric Golgi (COG) complex, a complex involved in vesicular Golgi trafficking, expanded the field of CDG but also brought novel insights in glycosylation. The molecular mechanisms underlying the complex pathway of N-glycosylation in the Golgi are far from understood. The availability of COG-deficient CDG patients and patients' cells offered a new way to study how COG, and its different subunits, could influence the Golgi N-glycosylation machinery and localization. This review summarizes the recent findings on the implication of COG in Golgi glycosylation. It highlights the need for a dynamic, finely tuned balance between anterograde and retrograde trafficking for the correct localization of Golgi enzymes to assure the stepwise maturation of N-glycan chains.
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Affiliation(s)
- Ellen Reynders
- Laboratory for Membrane Trafficking, Center for Human Genetics, KULeuven, Department for Molecular and Developmental Genetics (VIB), Leuven, Belgium
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35
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Molecular organization of the COG vesicle tethering complex. Nat Struct Mol Biol 2010; 17:1292-7. [PMID: 20972446 PMCID: PMC3113405 DOI: 10.1038/nsmb.1917] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2010] [Accepted: 08/19/2010] [Indexed: 11/08/2022]
Abstract
Multisubunit tethering complexes of the CATCHR (Complexes Associated with Tethering Containing Helical Rods) family are proposed to mediate the initial contact between an intracellular trafficking vesicle and its membrane target. To begin elucidating the molecular architecture of one well-studied example, the COG (conserved oligomeric Golgi) complex, we reconstituted its essential subunits (Cog1, Cog2, Cog3, and Cog4) and used single-particle electron microscopy to reveal a y-shaped structure with three flexible, highly extended legs. Labeling experiments established that the N-termini of all four subunits interact along the proximal segment of one leg, whereas three of the four C-termini are located at the tips of the legs. Our results suggest that the central region of the Cog1-4 complex, as well as the distal regions of at least two legs, all participate in interactions with other components of the intracellular trafficking machinery.
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36
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Angers CG, Merz AJ. New links between vesicle coats and Rab-mediated vesicle targeting. Semin Cell Dev Biol 2010; 22:18-26. [PMID: 20643221 DOI: 10.1016/j.semcdb.2010.07.003] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2010] [Revised: 07/07/2010] [Accepted: 07/09/2010] [Indexed: 12/24/2022]
Abstract
Vesicle trafficking is a highly regulated process that transports proteins and other cargoes through eukaryotic cells while maintaining cellular organization and compartmental identity. In order for cargo to reach the correct destination, each step of trafficking must impart specificity. During vesicle formation, this is achieved by coat proteins, which selectively incorporate cargo into the nascent vesicle. Classically, vesicle coats are thought to dissociate shortly after budding. However, recent studies suggest that coat proteins can remain on the vesicle en route to their destination, imparting targeting specificity by physically and functionally interacting with Rab-regulated tethering systems. This review focuses on how interactions among Rab GTPases, tethering factors, SNARE proteins, and vesicle coats contribute to vesicle targeting, fusion, and coat dynamics.
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Affiliation(s)
- Cortney G Angers
- Department of Biochemistry, University of Washington School of Medicine, Seattle, WA 98195-3750, USA
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37
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Oliveira DL, Nakayasu ES, Joffe LS, Guimarães AJ, Sobreira TJP, Nosanchuk JD, Cordero RJB, Frases S, Casadevall A, Almeida IC, Nimrichter L, Rodrigues ML. Characterization of yeast extracellular vesicles: evidence for the participation of different pathways of cellular traffic in vesicle biogenesis. PLoS One 2010; 5:e11113. [PMID: 20559436 PMCID: PMC2885426 DOI: 10.1371/journal.pone.0011113] [Citation(s) in RCA: 193] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2010] [Accepted: 05/21/2010] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Extracellular vesicles in yeast cells are involved in the molecular traffic across the cell wall. In yeast pathogens, these vesicles have been implicated in the transport of proteins, lipids, polysaccharide and pigments to the extracellular space. Cellular pathways required for the biogenesis of yeast extracellular vesicles are largely unknown. METHODOLOGY/PRINCIPAL FINDINGS We characterized extracellular vesicle production in wild type (WT) and mutant strains of the model yeast Saccharomyces cerevisiae using transmission electron microscopy in combination with light scattering analysis, lipid extraction and proteomics. WT cells and mutants with defective expression of Sec4p, a secretory vesicle-associated Rab GTPase essential for Golgi-derived exocytosis, or Snf7p, which is involved in multivesicular body (MVB) formation, were analyzed in parallel. Bilayered vesicles with diameters at the 100-300 nm range were found in extracellular fractions from yeast cultures. Proteomic analysis of vesicular fractions from the cells aforementioned and additional mutants with defects in conventional secretion pathways (sec1-1, fusion of Golgi-derived exocytic vesicles with the plasma membrane; bos1-1, vesicle targeting to the Golgi complex) or MVB functionality (vps23, late endosomal trafficking) revealed a complex and interrelated protein collection. Semi-quantitative analysis of protein abundance revealed that mutations in both MVB- and Golgi-derived pathways affected the composition of yeast extracellular vesicles, but none abrogated vesicle production. Lipid analysis revealed that mutants with defects in Golgi-related components of the secretory pathway had slower vesicle release kinetics, as inferred from intracellular accumulation of sterols and reduced detection of these lipids in vesicle fractions in comparison with WT cells. CONCLUSIONS/SIGNIFICANCE Our results suggest that both conventional and unconventional pathways of secretion are required for biogenesis of extracellular vesicles, which demonstrate the complexity of this process in the biology of yeast cells.
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Affiliation(s)
- Débora L. Oliveira
- Laboratório de Estudos Integrados em Bioquímica Microbiana, Instituto de Microbiologia Professor Paulo de Góes, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Ernesto S. Nakayasu
- Department of Biological Sciences, The Border Biomedical Research Center, University of Texas at El Paso, El Paso, Texas, United States of America
| | - Luna S. Joffe
- Laboratório de Estudos Integrados em Bioquímica Microbiana, Instituto de Microbiologia Professor Paulo de Góes, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Allan J. Guimarães
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Tiago J. P. Sobreira
- Laboratory of Genetics and Molecular Cardiology, Heart Institute (InCor), University of São Paulo, São Paulo, São Paulo, Brazil
| | - Joshua D. Nosanchuk
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, United States of America
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Radames J. B. Cordero
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Susana Frases
- Laboratório de Biotecnologia, Instituto Nacional de Metrologia, Normalização e Qualidade Industrial, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Arturo Casadevall
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, United States of America
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Igor C. Almeida
- Department of Biological Sciences, The Border Biomedical Research Center, University of Texas at El Paso, El Paso, Texas, United States of America
| | - Leonardo Nimrichter
- Laboratório de Estudos Integrados em Bioquímica Microbiana, Instituto de Microbiologia Professor Paulo de Góes, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Marcio L. Rodrigues
- Laboratório de Estudos Integrados em Bioquímica Microbiana, Instituto de Microbiologia Professor Paulo de Góes, Rio de Janeiro, Rio de Janeiro, Brazil
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Yen WL, Shintani T, Nair U, Cao Y, Richardson BC, Li Z, Hughson FM, Baba M, Klionsky DJ. The conserved oligomeric Golgi complex is involved in double-membrane vesicle formation during autophagy. ACTA ACUST UNITED AC 2010; 188:101-14. [PMID: 20065092 PMCID: PMC2812853 DOI: 10.1083/jcb.200904075] [Citation(s) in RCA: 155] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Macroautophagy is a catabolic pathway used for the turnover of long-lived proteins and organelles in eukaryotic cells. The morphological hallmark of this process is the formation of double-membrane autophagosomes that sequester cytoplasm. Autophagosome formation is the most complex part of macroautophagy, and it is a dynamic event that likely involves vesicle fusion to expand the initial sequestering membrane, the phagophore; however, essentially nothing is known about this process including the molecular components involved in vesicle tethering and fusion. In this study, we provide evidence that the subunits of the conserved oligomeric Golgi (COG) complex are required for double-membrane cytoplasm to vacuole targeting vesicle and autophagosome formation. COG subunits localized to the phagophore assembly site and interacted with Atg (autophagy related) proteins. In addition, mutations in the COG genes resulted in the mislocalization of Atg8 and Atg9, which are critical components involved in autophagosome formation.
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Affiliation(s)
- Wei-Lien Yen
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
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Sclafani A, Chen S, Rivera-Molina F, Reinisch K, Novick P, Ferro-Novick S. Establishing a role for the GTPase Ypt1p at the late Golgi. Traffic 2010; 11:520-32. [PMID: 20059749 DOI: 10.1111/j.1600-0854.2010.01031.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
GTPases of the Rab family cycle between an inactive (GDP-bound) and active (GTP-bound) conformation. The active form of the Rab regulates a variety of cellular functions via multiple effectors. Guanine nucleotide exchange factors (GEFs) activate Rabs by accelerating the exchange of GDP for GTP, while GTPase activating proteins (GAPs) inactivate Rabs by stimulating the hydrolysis of GTP. The GTPase Ypt1p is required for endoplasmic reticulum (ER)-Golgi and intra-Golgi traffic in the yeast Saccharomyces cerevisiae. Recent findings, however, have shown that Ypt1p GEF, GAP and an effector are all required for traffic from the early endosome to the Golgi. Here we describe a screen for ypt1 mutants that block traffic from the early endosome to the late Golgi, but not general secretion. This screen has led to the identification of a collection of recessive and dominant mutants that block traffic from the early endosome. While it has long been known that Ypt1p regulates the flow of biosynthetic traffic into the cis side of the Golgi, these findings have established a role for Ypt1p in the regulation of early endosome-Golgi traffic. We propose that Ypt1p regulates the flow of traffic into the cis and trans side of the Golgi via multiple effectors.
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Affiliation(s)
- Anthony Sclafani
- Department of Cell Biology, Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT 06519, USA
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40
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Sztul E, Lupashin V. Role of vesicle tethering factors in the ER-Golgi membrane traffic. FEBS Lett 2009; 583:3770-83. [PMID: 19887069 DOI: 10.1016/j.febslet.2009.10.083] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2009] [Revised: 10/29/2009] [Accepted: 10/30/2009] [Indexed: 12/27/2022]
Abstract
Tethers are a diverse group of loosely related proteins and protein complexes grouped into three families based on structural and functional similarities. A well-accepted role for tethering factors is the initial attachment of transport carriers to acceptor membranes prior to fusion. However, accumulating evidence indicates that tethers are more than static bridges. Tethers have been shown to interact with components of the fusion machinery and with components involved in vesicle formation. Tethers belonging to the three families act at the same stage of traffic, suggesting that they mediate distinct events during vesicle tethering. Thus, multiple tether-facilitated events are required to provide selectivity to vesicle fusion. In this review, we highlight findings that support this model.
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Affiliation(s)
- Elizabeth Sztul
- Department of Cell Biology, University of Alabama at Birmingham, 1918 University Boulevard, Birmingham, AL 35294, USA
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41
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Structural basis for a human glycosylation disorder caused by mutation of the COG4 gene. Proc Natl Acad Sci U S A 2009; 106:13329-34. [PMID: 19651599 DOI: 10.1073/pnas.0901966106] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The proper glycosylation of proteins trafficking through the Golgi apparatus depends upon the conserved oligomeric Golgi (COG) complex. Defects in COG can cause fatal congenital disorders of glycosylation (CDGs) in humans. The recent discovery of a form of CDG, caused in part by a COG4 missense mutation changing Arg 729 to Trp, prompted us to determine the 1.9 A crystal structure of a Cog4 C-terminal fragment. Arg 729 is found to occupy a key position at the center of a salt bridge network, thereby stabilizing Cog4's small C-terminal domain. Studies in HeLa cells reveal that this C-terminal domain, while not needed for the incorporation of Cog4 into COG complexes, is essential for the proper glycosylation of cell surface proteins. We also find that Cog4 bears a strong structural resemblance to exocyst and Dsl1p complex subunits. These complexes and others have been proposed to function by mediating the initial tethering between transport vesicles and their membrane targets; the emerging structural similarities provide strong evidence of a common evolutionary origin and may reflect shared mechanisms of action.
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42
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Dual roles of the mammalian GARP complex in tethering and SNARE complex assembly at the trans-golgi network. Mol Cell Biol 2009; 29:5251-63. [PMID: 19620288 DOI: 10.1128/mcb.00495-09] [Citation(s) in RCA: 121] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Tethering factors and SNAREs control the last two steps of vesicular trafficking: the initial interaction and the fusion, respectively, of transport vesicles with target membranes. The Golgi-associated retrograde protein (GARP) complex regulates retrograde transport from endosomes to the trans-Golgi network (TGN). Although GARP has been proposed to function as a tethering factor at the TGN, direct evidence for such a role is still lacking. Herein we report novel and specific interactions of the mammalian GARP complex with SNAREs that participate in endosome-to-TGN transport, namely, syntaxin 6, syntaxin 16, and Vamp4. These interactions depend on the N-terminal regions of Vps53 and Vps54 and the SNARE motif of the SNAREs. We show that GARP functions upstream of the SNAREs, regulating their localization and assembly into SNARE complexes. However, interactions of GARP with SNAREs are insufficient to promote retrograde transport, because deletion of the C-terminal region of Vps53 precludes GARP function without affecting GARP-SNARE interactions. Finally, we present in vitro data consistent with a tethering role for GARP, which is disrupted by deletion of the Vps53 C-terminal region. These findings indicate that GARP orchestrates retrograde transport from endosomes to the TGN by promoting vesicle tethering and assembly of SNARE complexes in consecutive, independent steps.
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43
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Lorente-Rodríguez A, Heidtman M, Barlowe C. Multicopy suppressor analysis of thermosensitive YIP1 alleles implicates GOT1 in transport from the ER. J Cell Sci 2009; 122:1540-50. [PMID: 19383723 DOI: 10.1242/jcs.042457] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Yip1p belongs to a conserved family of membrane-spanning proteins that are involved in intracellular trafficking. Studies have shown that Yip1p forms a heteromeric integral membrane complex, is required for biogenesis of ER-derived COPII vesicles, and can interact with Rab GTPases. However, the role of the Yip1 complex in vesicle budding is not well understood. To gain further insight, we isolated multicopy suppressors of the thermosensitive yip1-2 allele. This screen identified GOT1, FYV8 and TSC3 as novel high-copy suppressors. The strongest suppressor, GOT1, also displayed moderate suppressor activity toward temperature-sensitive mutations in the SEC23 and SEC31 genes, which encode subunits of the COPII coat. Further characterization of Got1p revealed that this protein was efficiently packaged into COPII vesicles and cycled rapidly between the ER and Golgi compartments. Based on the findings we propose that Got1p has an unexpected role in vesicle formation from the ER by influencing membrane properties.
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Castillon GA, Watanabe R, Taylor M, Schwabe TME, Riezman H. Concentration of GPI-anchored proteins upon ER exit in yeast. Traffic 2008; 10:186-200. [PMID: 19054390 DOI: 10.1111/j.1600-0854.2008.00857.x] [Citation(s) in RCA: 134] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Previous biochemical work has revealed two parallel routes of exit from the endoplasmic reticulum (ER) in the yeast Saccharomyces cerevisiae, one seemingly specific for glycosyl-phosphatidylinositol (GPI)-anchored proteins. Using the coat protein II (COPII) mutant sec31-1, we visualized ER exit sites (ERES) and identified three distinct ERES populations in vivo. One contains glycosylated pro-alpha-factor, the second contains the GPI-anchored proteins Cwp2p, Ccw14p and Tos6p and the third is enriched with the hexose transporter, Hxt1p. Concentration of GPI-anchored proteins prior to budding requires anchor remodeling, and Hxt1p incorporation into ERES requires the COPII components Sec12p and Sec16p. Additionally, we have found that GPI-anchored protein ER exit is controlled by the p24 family member Emp24p, whereas ER export of most transmembrane proteins requires the Cornichon homologue Erv14p.
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Affiliation(s)
- Guillaume A Castillon
- Department of Biochemistry, University of Geneva, Sciences II, 30 quai Ernest Ansermet, CH-1211 Geneva, Switzerland
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45
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Foulquier F. COG defects, birth and rise! Biochim Biophys Acta Mol Basis Dis 2008; 1792:896-902. [PMID: 19028570 DOI: 10.1016/j.bbadis.2008.10.020] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2008] [Accepted: 10/22/2008] [Indexed: 10/21/2022]
Abstract
The COG complex is a cytosolic heteromeric Golgi complex constituted of 8 subunits (Cog1 to Cog8) and involved in retrograde vesicular Golgi trafficking. The involvement of this complex in glycosylation and more specifically in Golgi glycosyltransferases localization has been highlighted with the discovery of COG subunit deficiencies leading to CDG (Congenital Disorders of Glycosylation), a group of inherited disorders of glycosylation. To date, many COG deficient CDG patients have been discovered and this article reviews the birth and rise of this group of defects. The architecture of the COG complex and its cellular functions in Golgi trafficking and Golgi glycosylation are discussed.
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Affiliation(s)
- François Foulquier
- Unité de Glycobiologie Structurale et Fonctionnelle UMR/CNRS 8576, IFR147, Université des Sciences et Technologies de Lille, France.
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46
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Rieder SE, Emr SD. Overview of subcellular fractionation procedures for the yeast Saccharomyces cerevisiae. ACTA ACUST UNITED AC 2008; Chapter 3:Unit 3.7. [PMID: 18228359 DOI: 10.1002/0471143030.cb0307s07] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
This unit provides an overview of centrifugation-based fractionation procedures adapted for the yeast Saccharomyces cerevisiae. The goals, merits, limitations, and critical parameters of are discussed in order to facilitate the development of subcellular fractionation strategies. Topics include yeast cell lysate preparation, differential velocity centrifugation, density gradient centrifugation, and the analysis of subcellular fractions.
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Affiliation(s)
- S E Rieder
- University of California, San Diego, La Jolla, California, USA
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47
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Role of the conserved oligomeric Golgi (COG) complex in protein glycosylation. Carbohydr Res 2008; 343:2024-31. [PMID: 18353293 DOI: 10.1016/j.carres.2008.01.034] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2007] [Revised: 01/23/2008] [Accepted: 01/24/2008] [Indexed: 11/20/2022]
Abstract
The Golgi apparatus is a central hub for both protein and lipid trafficking/sorting and is also a major site for glycosylation in the cell. This organelle employs a cohort of peripheral membrane proteins and protein complexes to keep its structural and functional organization. The conserved oligomeric Golgi (COG) complex is an evolutionary conserved peripheral membrane protein complex that is proposed to act as a retrograde vesicle tethering factor in intra-Golgi trafficking. The COG protein complex consists of eight subunits, distributed in two lobes, Lobe A (Cog1-4) and Lobe B (Cog5-8). Malfunctions in the COG complex have a significant impact on processes such as protein sorting, glycosylation, and Golgi integrity. A deletion of Lobe A COG subunits in yeasts causes severe growth defects while mutations in COG1, COG7, and COG8 in humans cause novel types of congenital disorders of glycosylation. These pathologies involve a change in structural Golgi phenotype and function. Recent results indicate that down-regulation of COG function results in the resident Golgi glycosyltransferases/glycosidases to be mislocalized or degraded.
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48
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Shestakova A, Suvorova E, Pavliv O, Khaidakova G, Lupashin V. Interaction of the conserved oligomeric Golgi complex with t-SNARE Syntaxin5a/Sed5 enhances intra-Golgi SNARE complex stability. ACTA ACUST UNITED AC 2008; 179:1179-92. [PMID: 18086915 PMCID: PMC2140037 DOI: 10.1083/jcb.200705145] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Tethering factors mediate initial interaction of transport vesicles with target membranes. Soluble N-ethylmaleimide–sensitive fusion protein attachment protein receptors (SNAREs) enable consequent docking and membrane fusion. We demonstrate that the vesicle tether conserved oligomeric Golgi (COG) complex colocalizes and coimmunoprecipitates with intra-Golgi SNARE molecules. In yeast cells, the COG complex preferentially interacts with the SNARE complexes containing yeast Golgi target (t)-SNARE Sed5p. In mammalian cells, hCog4p and hCog6p interact with Syntaxin5a, the mammalian homologue of Sed5p. Moreover, fluorescence resonance energy transfer reveals an in vivo interaction between Syntaxin5a and the COG complex. Knockdown of the mammalian COG complex decreases Golgi SNARE mobility, produces an accumulation of free Syntaxin5, and decreases the steady-state levels of the intra-Golgi SNARE complex. Finally, overexpression of the hCog4p N-terminal Syntaxin5a-binding domain destabilizes intra-Golgi SNARE complexes, disrupting the Golgi. These data suggest that the COG complex orchestrates vesicular trafficking similarly in yeast and mammalian cells by binding to the t-SNARE Syntaxin5a/Sed5p and enhancing the stability of intra-Golgi SNARE complexes.
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Affiliation(s)
- Anna Shestakova
- Department of Physiology and Biophysics, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
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49
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Zeevaert R, Foulquier F, Jaeken J, Matthijs G. Deficiencies in subunits of the Conserved Oligomeric Golgi (COG) complex define a novel group of Congenital Disorders of Glycosylation. Mol Genet Metab 2008; 93:15-21. [PMID: 17904886 DOI: 10.1016/j.ymgme.2007.08.118] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2007] [Revised: 08/16/2007] [Accepted: 08/16/2007] [Indexed: 11/20/2022]
Abstract
Processing of the glycan structures on glycoproteins by different glycosylation enzymes depends on, among other, the non-uniform distribution of these enzymes within the Golgi stacks. This compartmentalization is achieved by a balance between anterograde and retrograde vesicular trafficking. If the balance is disturbed, the glycosylation machinery is mislocalized, which can cause Congenital Disorders of Glycosylation type II (CDG-II), as illustrated by the identification of congenital defects in the Conserved Oligomeric Golgi (COG) complex in humans. We collected findings from different COG deficient cell types, such as CHO, yeast and human fibroblasts to hypothesize about structure and function of the COG complex, and compared the phenotypes and genotypes of the patients known with a COG deficiency. Among 35 CDG-II patients we found 5 patients with a COG defect. COG defects are a novel group of CDG-II with deficient N- as well as O-glycosylation.
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Affiliation(s)
- Renate Zeevaert
- Center for Human Genetics, University Hospital Gasthuisberg, Herestraat 49, B3000 Leuven, Belgium
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50
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Cavanaugh LF, Chen X, Richardson BC, Ungar D, Pelczer I, Rizo J, Hughson FM. Structural analysis of conserved oligomeric Golgi complex subunit 2. J Biol Chem 2007; 282:23418-26. [PMID: 17565980 DOI: 10.1074/jbc.m703716200] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The conserved oligomeric Golgi (COG) complex is strongly implicated in retrograde vesicular trafficking within the Golgi apparatus. Although its mechanism of action is poorly understood, it has been proposed to function by mediating the initial physical contact between transport vesicles and their membrane targets. An analogous role in tethering vesicles has been suggested for at least six additional large multisubunit complexes, including the exocyst, a complex essential for trafficking to the plasma membrane. Here we report the solution structure of a large portion of yeast Cog2p, one of eight subunits composing the COG complex. The structure reveals a six-helix bundle with few conserved surface features but a general resemblance to recently determined crystal structures of four different exocyst subunits. This finding provides the first structural evidence that COG, like the exocyst and potentially other tethering complexes, is constructed from helical bundles. These structures may represent platforms for interaction with other trafficking proteins including SNAREs (soluble N-ethylmaleimide factor attachment protein receptors) and Rabs.
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Affiliation(s)
- Lorraine F Cavanaugh
- Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544, USA
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