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Magliozzi JO, Rands TJ, Shrestha S, Simke WC, Hase NE, Juanes MA, Kelley JB, Goode BL. The roles of yeast formins and their regulators Bud6 and Bil2 in the pheromone response. Mol Biol Cell 2024; 35:ar85. [PMID: 38656798 PMCID: PMC11238086 DOI: 10.1091/mbc.e23-11-0459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 04/09/2024] [Accepted: 04/17/2024] [Indexed: 04/26/2024] Open
Abstract
In response to pheromone Saccharomyces cerevisiae extend a mating projection. This process depends on the formation of polarized actin cables which direct secretion to the mating tip and translocate the nucleus for karyogamy. Here, we demonstrate that proper mating projection formation requires the formin Bni1, as well as the actin nucleation promoting activities of Bud6, but not the formin Bnr1. Further, Bni1 is required for pheromone gradient tracking. Our work also reveals unexpected new functions for Bil2 in the pheromone response. Previously we identified Bil2 as a direct inhibitor of Bnr1 during vegetative cell growth. Here, we show that Bil2 has Bnr1-independent functions in spatially focusing Bni1-GFP at mating projection tips, and in vitro Bil2 and its binding partner Bud6 organize Bni1 into clusters that nucleate actin assembly. bil2∆ cells also display entangled Bni1-generated actin cable arrays and defects in secretory vesicle transport and nuclear positioning. At low pheromone concentrations, bil2∆ cells are delayed in establishing a polarity axis, and at high concentrations they prematurely form a second and a third mating projection. Together, these results suggest that Bil2 promotes the proper formation and timing of mating projections by organizing Bni1 and maintaining a persistent axis of polarized growth.
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Affiliation(s)
| | - Thomas J. Rands
- Department of Biology, Brandeis University, Waltham, MA 02454
| | - Sudati Shrestha
- Department of Molecular and Biomedical Sciences, University of Maine, Orono, ME 04469
| | - William C Simke
- Department of Molecular and Biomedical Sciences, University of Maine, Orono, ME 04469
| | - Niklas E. Hase
- Department of Molecular and Biomedical Sciences, University of Maine, Orono, ME 04469
| | - M. Angeles Juanes
- Department of Biology, Brandeis University, Waltham, MA 02454
- Centro de Investigación Príncipe Felipe, 46012 Valencia, Spain
| | - Joshua B. Kelley
- Department of Molecular and Biomedical Sciences, University of Maine, Orono, ME 04469
| | - Bruce L. Goode
- Department of Biology, Brandeis University, Waltham, MA 02454
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2
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Niedziółka SM, Datta S, Uśpieński T, Baran B, Skarżyńska W, Humke EW, Rohatgi R, Niewiadomski P. The exocyst complex and intracellular vesicles mediate soluble protein trafficking to the primary cilium. Commun Biol 2024; 7:213. [PMID: 38378792 PMCID: PMC10879184 DOI: 10.1038/s42003-024-05817-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Accepted: 01/15/2024] [Indexed: 02/22/2024] Open
Abstract
The efficient transport of proteins into the primary cilium is a crucial step for many signaling pathways. Dysfunction of this process can lead to the disruption of signaling cascades or cilium assembly, resulting in developmental disorders and cancer. Previous studies on the protein delivery to the cilium were mostly focused on the membrane-embedded receptors. In contrast, how soluble proteins are delivered into the cilium is poorly understood. In our work, we identify the exocyst complex as a key player in the ciliary trafficking of soluble Gli transcription factors. In line with the known function of the exocyst in intracellular vesicle transport, we demonstrate that soluble proteins, including Gli2/3 and Lkb1, can use the endosome recycling machinery for their delivery to the primary cilium. Finally, we identify GTPases: Rab14, Rab18, Rab23, and Arf4 that are involved in vesicle-mediated Gli protein ciliary trafficking. Our data pave the way for a better understanding of ciliary transport and uncover transport mechanisms inside the cell.
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Affiliation(s)
- S M Niedziółka
- Centre of New Technologies, University of Warsaw, Warsaw, Poland
- Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - S Datta
- Centre of New Technologies, University of Warsaw, Warsaw, Poland
| | - T Uśpieński
- Centre of New Technologies, University of Warsaw, Warsaw, Poland
- Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - B Baran
- Centre of New Technologies, University of Warsaw, Warsaw, Poland
- Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - W Skarżyńska
- Centre of New Technologies, University of Warsaw, Warsaw, Poland
| | - E W Humke
- Department of Medicine, Stanford University School of Medicine, Stanford, CA, USA
- IGM Biosciences, Inc, Mountain View, CA, USA
| | - R Rohatgi
- Department of Medicine, Stanford University School of Medicine, Stanford, CA, USA
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA, USA
| | - P Niewiadomski
- Centre of New Technologies, University of Warsaw, Warsaw, Poland.
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3
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Cullell N, Soriano-Tárraga C, Gallego-Fábrega C, Cárcel-Márquez J, Muiño E, Llucià-Carol L, Lledós M, Esteller M, de Moura MC, Montaner J, Rosell A, Delgado P, Martí-Fábregas J, Krupinski J, Roquer J, Jiménez-Conde J, Fernández-Cadenas I. Altered methylation pattern in EXOC4 is associated with stroke outcome: an epigenome-wide association study. Clin Epigenetics 2022; 14:124. [PMID: 36180927 PMCID: PMC9526296 DOI: 10.1186/s13148-022-01340-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 09/13/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND AND PURPOSE The neurological course after stroke is highly variable and is determined by demographic, clinical and genetic factors. However, other heritable factors such as epigenetic DNA methylation could play a role in neurological changes after stroke. METHODS We performed a three-stage epigenome-wide association study to evaluate DNA methylation associated with the difference between the National Institutes of Health Stroke Scale (NIHSS) at baseline and at discharge (ΔNIHSS) in ischaemic stroke patients. DNA methylation data in the Discovery (n = 643) and Replication (n = 62) Cohorts were interrogated with the 450 K and EPIC BeadChip. Nominal CpG sites from the Discovery (p value < 10-06) were also evaluated in a meta-analysis of the Discovery and Replication cohorts, using a random-fixed effect model. Metabolic pathway enrichment was calculated with methylGSA. We integrated the methylation data with 1305 plasma protein expression levels measured by SOMAscan in 46 subjects and measured RNA expression with RT-PCR in a subgroup of 13 subjects. Specific cell-type methylation was assessed using EpiDISH. RESULTS The meta-analysis revealed an epigenome-wide significant association in EXOC4 (p value = 8.4 × 10-08) and in MERTK (p value = 1.56 × 10-07). Only the methylation in EXOC4 was also associated in the Discovery and in the Replication Cohorts (p value = 1.14 × 10-06 and p value = 1.3 × 10-02, respectively). EXOC4 methylation negatively correlated with the long-term outcome (coefficient = - 4.91) and showed a tendency towards a decrease in EXOC4 expression (rho = - 0.469, p value = 0.091). Pathway enrichment from the meta-analysis revealed significant associations related to the endocytosis and deubiquitination processes. Seventy-nine plasma proteins were differentially expressed in association with EXOC4 methylation. Pathway analysis of these proteins showed an enrichment in natural killer (NK) cell activation. The cell-type methylation analysis in blood also revealed a differential methylation in NK cells. CONCLUSIONS DNA methylation of EXOC4 is associated with a worse neurological course after stroke. The results indicate a potential modulation of pathways involving endocytosis and NK cells regulation.
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Affiliation(s)
- Natalia Cullell
- Stroke Pharmacogenomics and Genetics, IIB-Sant Pau, Institut de Recerca de Sant Pau, Hospital Sant Pau, C/Sant Antoni Mª Claret,167, 08025, Barcelona, Spain
- Neurology, Hospital Universitari MútuaTerrassa/Fundacio Docència i Recerca MutuaTerrassa, Terrassa, Spain
- Facultat de Medicina, Universitat de Barcelona, Barcelona, Spain
| | - Carolina Soriano-Tárraga
- Neurology, Hospital del Mar, Neurovascular Research Group, IMIM, Universitat Autònoma de Barcelona/DCEXS-Universitat Pompeu Fabra, Barcelona, Spain
- Department of Psychiatry, Washington University School of Medicine, Saint Louis, Missouri, USA
- NeuroGenomics and Informatics, Washington University School of Medicine, Saint Louis, Missouri, USA
| | - Cristina Gallego-Fábrega
- Stroke Pharmacogenomics and Genetics, IIB-Sant Pau, Institut de Recerca de Sant Pau, Hospital Sant Pau, C/Sant Antoni Mª Claret,167, 08025, Barcelona, Spain
| | - Jara Cárcel-Márquez
- Stroke Pharmacogenomics and Genetics, IIB-Sant Pau, Institut de Recerca de Sant Pau, Hospital Sant Pau, C/Sant Antoni Mª Claret,167, 08025, Barcelona, Spain
| | - Elena Muiño
- Stroke Pharmacogenomics and Genetics, IIB-Sant Pau, Institut de Recerca de Sant Pau, Hospital Sant Pau, C/Sant Antoni Mª Claret,167, 08025, Barcelona, Spain
| | - Laia Llucià-Carol
- Stroke Pharmacogenomics and Genetics, IIB-Sant Pau, Institut de Recerca de Sant Pau, Hospital Sant Pau, C/Sant Antoni Mª Claret,167, 08025, Barcelona, Spain
| | - Miquel Lledós
- Stroke Pharmacogenomics and Genetics, IIB-Sant Pau, Institut de Recerca de Sant Pau, Hospital Sant Pau, C/Sant Antoni Mª Claret,167, 08025, Barcelona, Spain
| | - Manel Esteller
- Cancer Epigenetics & Biology Program (PEBC), L'Hospitalet, Spain
- Department of Physiological Sciences II, School of Medicine, Universitat de Barcelona, Barcelona, Spain
- Institució Catalana de Recerca I Estudis Avançats (ICREA), Barcelona, Spain
| | | | - Joan Montaner
- Neurovascular Research Laboratory, Vall d'Hebron Institut de Recerca (VHIR), Barcelona, Spain
- Department of Neurology, Hospital Universitario Virgen Macarena Sevilla, Instituto de Biomedicina de Sevilla, IBiS/Hospital Universitario Virgen del Rocío/CSIC, Universidad de Sevilla, Sevilla, Spain
| | - Anna Rosell
- Neurovascular Research Laboratory, Vall d'Hebron Institut de Recerca (VHIR), Barcelona, Spain
| | - Pilar Delgado
- Neurovascular Research Laboratory, Vall d'Hebron Institut de Recerca (VHIR), Barcelona, Spain
| | | | - Jerzy Krupinski
- Neurology, Hospital Universitari MútuaTerrassa/Fundacio Docència i Recerca MutuaTerrassa, Terrassa, Spain
- Centre for Bioscience, School of HealthCare Science, Manchester Metropolitan University, Manchester, UK
| | - Jaume Roquer
- Neurology, Hospital del Mar, Neurovascular Research Group, IMIM, Universitat Autònoma de Barcelona/DCEXS-Universitat Pompeu Fabra, Barcelona, Spain
| | - Jordi Jiménez-Conde
- Neurology, Hospital del Mar, Neurovascular Research Group, IMIM, Universitat Autònoma de Barcelona/DCEXS-Universitat Pompeu Fabra, Barcelona, Spain
| | - Israel Fernández-Cadenas
- Stroke Pharmacogenomics and Genetics, IIB-Sant Pau, Institut de Recerca de Sant Pau, Hospital Sant Pau, C/Sant Antoni Mª Claret,167, 08025, Barcelona, Spain.
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4
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Nakamura NK, Tokunaga DS, Ha HY, Polgar N. The Exocyst Is Required for CD36 Fatty Acid Translocase Trafficking and Free Fatty Acid Uptake in Skeletal Muscle Cells. Cells 2022; 11:2440. [PMID: 35954283 PMCID: PMC9368548 DOI: 10.3390/cells11152440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 07/31/2022] [Accepted: 08/03/2022] [Indexed: 11/26/2022] Open
Abstract
In obesity, chronic membrane-localization of CD36 free fatty acid (FFA) translocase, but not other FFA transporters, enhances FFA uptake and intracellular lipid accumulation. This ectopic lipid accumulation promotes insulin resistance by inhibiting insulin-induced GLUT4 glucose transporter trafficking and glucose uptake. GLUT4 and CD36 cell surface delivery is triggered by insulin- and contraction-induced signaling, which share conserved downstream effectors. While we have gathered detailed knowledge on GLUT4 trafficking, the mechanisms regulating CD36 membrane delivery and subsequent FFA uptake in skeletal muscle are not fully understood. The exocyst trafficking complex facilitates the docking of membrane-bound vesicles, a process underlying the controlled surface delivery of fuel transporters. The exocyst regulates insulin-induced glucose uptake via GLUT4 membrane trafficking in adipocytes and skeletal muscle cells and plays a role in lipid uptake in adipocytes. Based on the high degree of conservation of the GLUT4 and CD36 trafficking mechanisms in adipose and skeletal muscle tissue, we hypothesized that the exocyst also contributes to lipid uptake in skeletal muscle and acts through the targeted plasma membrane delivery of CD36 in response to insulin and contraction. Here, we show that the exocyst complex is necessary for insulin- and contraction-induced CD36 membrane trafficking and FFA uptake in muscle cells.
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Affiliation(s)
| | | | | | - Noemi Polgar
- Department of Anatomy, Biochemistry, and Physiology, John A. Burns School of Medicine, University of Hawaii, Honolulu, HI 96813, USA
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5
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Dahhan DA, Bednarek SY. Advances in structural, spatial, and temporal mechanics of plant endocytosis. FEBS Lett 2022; 596:2269-2287. [PMID: 35674447 DOI: 10.1002/1873-3468.14420] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 05/27/2022] [Accepted: 05/31/2022] [Indexed: 11/06/2022]
Abstract
Endocytic trafficking underlies processes essential for plant growth and development, including the perception of and response to abiotic and extracellular stimuli, post-Golgi and exocytic trafficking, and cytokinesis. Protein adaptors and regulatory factors of clathrin-mediated endocytosis that contribute to the formation of endocytic clathrin-coated vesicles are evolutionarily conserved. Yet, work of the last ten years has identified differences between the endocytic mechanisms of plants and Opisthokonts involving the endocytic adaptor TPLATE complex, the requirement of actin during CME, and the function of clathrin-independent endocytosis in the uptake of plant-specific plasma membrane proteins. Here, we review clathrin-mediated and -independent pathways in plants and describe recent advances enabled by new proteomic and imaging methods, and conditional perturbation of endocytosis. In addition, we summarize the formation and trafficking of clathrin-coated vesicles based on temporal and structural data garnered from high-resolution quantitative imaging studies. Finally, new information about the cross-talk between endocytosis and other endomembrane trafficking pathways and organelles will also be discussed.
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Affiliation(s)
- Dana A Dahhan
- Department of Biochemistry, University of Wisconsin-Madison, WI, USA
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6
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Wang F, Cheng Z, Wang J, Zhang F, Zhang B, Luo S, Lei C, Pan T, Wang Y, Zhu Y, Wang M, Chen W, Lin Q, Zhu S, Zhou Y, Zhao Z, Wang J, Guo X, Zhang X, Jiang L, Bao Y, Ren Y, Wan J. Rice STOMATAL CYTOKINESIS DEFECTIVE2 regulates cell expansion by affecting vesicular trafficking in rice. PLANT PHYSIOLOGY 2022; 189:567-584. [PMID: 35234957 PMCID: PMC9157159 DOI: 10.1093/plphys/kiac073] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 01/20/2022] [Indexed: 05/13/2023]
Abstract
Vesicular trafficking plays critical roles in cell expansion in yeast and mammals, but information linking vesicular trafficking and cell expansion in plants is limited. Here, we isolated and characterized a rice (Oryza sativa) mutant, decreased plant height 1-1 (dph1-1), which exhibited a wide spectrum of developmental phenotypes, including reduced plant height and smaller panicles and grains. Cytological analysis revealed that limited cell expansion was responsible for the dph1-1 mutant phenotype compared to the wild-type. Map-based cloning revealed that DPH1 encodes a plant-specific protein, OsSCD2, which is homologous to Arabidopsis (Arabidopsis thaliana) STOMATAL CYTOKINESIS DEFECTIVE2 (SCD2). Subcellular localization revealed that OsSCD2 is associated with clathrin. Confocal microscopy showed that the dph1-1 mutant has defective endocytosis and post-Golgi trafficking. Biochemical and confocal data indicated that OsSCD2 physically interacts with OsSCD1 and that they are associated with intracellular structures that colocalize with microtubules. Furthermore, we found that cellulose synthesis was affected in the dph1-1 mutant, evidenced by reduced cellulose synthase gene accumulation at the transcript and protein levels, most likely resulting from an impaired localization pattern. Our results suggest that OsSCD2 is involved in clathrin-related vesicular trafficking with an important role in maintaining plant growth in rice.
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Affiliation(s)
- Fan Wang
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, China
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Zhijun Cheng
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Jiachang Wang
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, China
| | - Feng Zhang
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Baocai Zhang
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing 100101, China
| | - Sheng Luo
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Cailin Lei
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Tian Pan
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, China
| | - Yongfei Wang
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, China
| | - Yun Zhu
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Min Wang
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Weiwei Chen
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Qibing Lin
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Shanshan Zhu
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Yihua Zhou
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing 100101, China
| | - Zhichao Zhao
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Jie Wang
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Xiuping Guo
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Xin Zhang
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Ling Jiang
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, China
| | - Yiqun Bao
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Yulong Ren
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Jianmin Wan
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, China
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China
- Author for correspondence: ,
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7
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Yan X, Wang Y, Xu M, Dahhan DA, Liu C, Zhang Y, Lin J, Bednarek SY, Pan J. Cross-talk between clathrin-dependent post-Golgi trafficking and clathrin-mediated endocytosis in Arabidopsis root cells. THE PLANT CELL 2021; 33:3057-3075. [PMID: 34240193 PMCID: PMC8462817 DOI: 10.1093/plcell/koab180] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 06/30/2021] [Indexed: 05/26/2023]
Abstract
Coupling of post-Golgi and endocytic membrane transport ensures that the flow of materials to/from the plasma membrane (PM) is properly balanced. The mechanisms underlying the coordinated trafficking of PM proteins in plants, however, are not well understood. In plant cells, clathrin and its adaptor protein complexes, AP-2 and the TPLATE complex (TPC) at the PM, and AP-1 at the trans-Golgi network/early endosome (TGN/EE), function in clathrin-mediated endocytosis (CME) and post-Golgi trafficking. Here, we utilized mutants with defects in clathrin-dependent post-Golgi trafficking and CME, in combination with other cytological and pharmacological approaches, to further investigate the machinery behind the coordination of protein delivery and recycling to/from the TGN/EE and PM in Arabidopsis (Arabidopsis thaliana) root cells. In mutants with defective AP-2-/TPC-dependent CME, we determined that clathrin and AP-1 recruitment to the TGN/EE as well as exocytosis are significantly impaired. Likewise, defects in AP-1-dependent post-Golgi trafficking and pharmacological inhibition of exocytosis resulted in the reduced association of clathrin and AP-2/TPC subunits with the PM and a reduction in the internalization of cargoes via CME. Together, these results suggest that post-Golgi trafficking and CME are coupled via modulation of clathrin and adaptor protein complex recruitment to the TGN/EE and PM.
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Affiliation(s)
- Xu Yan
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Yutong Wang
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Mei Xu
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Dana A. Dahhan
- Department of Biochemistry, University of Wisconsin–Madison, Madison, Wisconsin 53706
| | - Chan Liu
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Yan Zhang
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai’an 271018, China
| | - Jinxing Lin
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, China
| | - Sebastian Y. Bednarek
- Department of Biochemistry, University of Wisconsin–Madison, Madison, Wisconsin 53706
| | - Jianwei Pan
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
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8
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Pushpa K, Dagar S, Kumar H, Pathak D, Mylavarapu SVS. The exocyst complex regulates C. elegans germline stem cell proliferation by controlling membrane Notch levels. Development 2021; 148:271155. [PMID: 34338279 DOI: 10.1242/dev.196345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 06/30/2021] [Indexed: 11/20/2022]
Abstract
The conserved exocyst complex regulates plasma membrane-directed vesicle fusion in eukaryotes. However, its role in stem cell proliferation has not been reported. Germline stem cell (GSC) proliferation in the nematode Caenorhabditis elegans is regulated by conserved Notch signaling. Here, we reveal that the exocyst complex regulates C. elegans GSC proliferation by modulating Notch signaling cell autonomously. Notch membrane density is asymmetrically maintained on GSCs. Knockdown of exocyst complex subunits or of the exocyst-interacting GTPases Rab5 and Rab11 leads to Notch redistribution from the GSC-niche interface to the cytoplasm, suggesting defects in plasma membrane Notch deposition. The anterior polarity (aPar) protein Par6 is required for GSC proliferation, and for maintaining niche-facing membrane levels of Notch and the exocyst complex. The exocyst complex biochemically interacts with the aPar regulator Par5 (14-3-3ζ) and Notch in C. elegans and human cells. Exocyst components are required for Notch plasma membrane localization and signaling in mammalian cells. Our study uncovers a possibly conserved requirement of the exocyst complex in regulating GSC proliferation and in maintaining optimal membrane Notch levels.
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Affiliation(s)
- Kumari Pushpa
- Laboratory of Cellular Dynamics, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone Faridabad-Gurgaon Expressway, Faridabad, Haryana 121001, India
| | - Sunayana Dagar
- Laboratory of Cellular Dynamics, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone Faridabad-Gurgaon Expressway, Faridabad, Haryana 121001, India.,Kalinga Institute of Industrial Technology, Bhubaneswar, Odisha 751024, India
| | - Harsh Kumar
- Laboratory of Cellular Dynamics, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone Faridabad-Gurgaon Expressway, Faridabad, Haryana 121001, India.,Manipal Academy of Higher Education, Manipal, Karnataka 576104, India
| | - Diksha Pathak
- Laboratory of Cellular Dynamics, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone Faridabad-Gurgaon Expressway, Faridabad, Haryana 121001, India
| | - Sivaram V S Mylavarapu
- Laboratory of Cellular Dynamics, Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone Faridabad-Gurgaon Expressway, Faridabad, Haryana 121001, India.,Kalinga Institute of Industrial Technology, Bhubaneswar, Odisha 751024, India.,Manipal Academy of Higher Education, Manipal, Karnataka 576104, India
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9
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Glomb O, Wu Y, Rieger L, Rüthnick D, Mulaw MA, Johnsson N. The cell polarity proteins Boi1 and Boi2 direct an actin nucleation complex to sites of exocytosis in Saccharomyces cerevisiae. J Cell Sci 2020; 133:jcs.237982. [PMID: 31964708 DOI: 10.1242/jcs.237982] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Accepted: 12/19/2019] [Indexed: 01/13/2023] Open
Abstract
Owing to the local enrichment of factors that influence its dynamics and organization, the actin cytoskeleton displays different shapes and functions within the same cell. In yeast cells, post-Golgi vesicles ride on long actin cables to the bud tip. The proteins Boi1 and Boi2 (Boi1/2) participate in tethering and docking these vesicles to the plasma membrane. Here, we show in Saccharomyces cerevisiae that Boi1/2 also recruit nucleation and elongation factors to form actin filaments at sites of exocytosis. Disrupting the connection between Boi1/2 and the nucleation factor Bud6 impairs filament formation, reduces the directed movement of the vesicles to the tip and shortens the vesicles' tethering time at the cortex. Transplanting Boi1 from the bud tip to the peroxisomal membrane partially redirects the actin cytoskeleton and the vesicular flow towards the peroxisome, and creates an alternative, rudimentary vesicle-docking zone. We conclude that Boi1/2, through interactions with Bud6 and Bni1, induce the formation of a cortical actin structure that receives and aligns incoming vesicles before fusion with the membrane.
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Affiliation(s)
- Oliver Glomb
- Institute of Molecular Genetics and Cell Biology, Department of Biology, Ulm University, James-Franck-Ring N27, D-89081 Ulm, Germany
| | - Yehui Wu
- Institute of Molecular Genetics and Cell Biology, Department of Biology, Ulm University, James-Franck-Ring N27, D-89081 Ulm, Germany
| | - Lucia Rieger
- Institute of Molecular Genetics and Cell Biology, Department of Biology, Ulm University, James-Franck-Ring N27, D-89081 Ulm, Germany
| | - Diana Rüthnick
- ZMBH, University of Heidelberg, Im Neuenheimer Feld 282, D-69120 Heidelberg, Germany
| | - Medhanie A Mulaw
- Comprehensive Cancer Center Ulm, Institute of Experimental Cancer Research, Ulm University, James-Franck-Ring N27, D-89081 Ulm, Germany
| | - Nils Johnsson
- Institute of Molecular Genetics and Cell Biology, Department of Biology, Ulm University, James-Franck-Ring N27, D-89081 Ulm, Germany
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10
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Boehm C, Field MC. Evolution of late steps in exocytosis: conservation and specialization of the exocyst complex. Wellcome Open Res 2019; 4:112. [PMID: 31633057 PMCID: PMC6784791 DOI: 10.12688/wellcomeopenres.15142.2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/18/2019] [Indexed: 01/09/2023] Open
Abstract
Background: The eukaryotic endomembrane system most likely arose
via paralogous expansions of genes encoding proteins that specify organelle identity, coat complexes and govern fusion specificity. While the majority of these gene families were established by the time of the last eukaryotic common ancestor (LECA), subsequent evolutionary events has moulded these systems, likely reflecting adaptations retained for increased fitness. As well as sequence evolution, these adaptations include loss of otherwise canonical components, the emergence of lineage-specific proteins and paralog expansion. The exocyst complex is involved in late exocytosis and additional trafficking pathways and a member of the complexes associated with tethering containing helical rods (CATCHR) tethering complex family. CATCHR includes the conserved oligomeric Golgi (COG) complex, homotypic fusion and vacuole protein sorting (HOPS)/class C core vacuole/endosome tethering (CORVET) complexes and several others. The exocyst is integrated into a complex GTPase signalling network in animals, fungi and other lineages. Prompted by discovery of Exo99, a non-canonical subunit in the excavate protist
Trypanosoma brucei, and availability of significantly increased genome sequence data, we re-examined evolution of the exocyst. Methods: We examined the evolution of exocyst components by comparative genomics, phylogenetics and structure prediction. Results: The exocyst composition is highly conserved, but with substantial losses of subunits in the Apicomplexa and expansions in Streptophyta plants, Metazoa and land plants, where for the latter, massive paralog expansion of Exo70 represents an extreme and unique example. Significantly, few taxa retain a partial complex, suggesting that, in general, all subunits are probably required for functionality. Further, the ninth exocyst subunit, Exo99, is specific to the Euglenozoa with a distinct architecture compared to the other subunits and which possibly represents a coat system. Conclusions: These data reveal a remarkable degree of evolutionary flexibility within the exocyst complex, suggesting significant diversity in exocytosis mechanisms.
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Affiliation(s)
- Cordula Boehm
- School of Life Sciences, University of Dundee, Dow Street, Dundee, DD1 5EH, UK
| | - Mark C Field
- School of Life Sciences, University of Dundee, Dow Street, Dundee, DD1 5EH, UK.,Biology Centre, Institute of Parasitology, Czech Academy of Sciences, České Budějovic, 37005, Czech Republic
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11
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Boehm C, Field MC. Evolution of late steps in exocytosis: conservation, specialization. Wellcome Open Res 2019; 4:112. [DOI: 10.12688/wellcomeopenres.15142.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/11/2019] [Indexed: 11/20/2022] Open
Abstract
Background:The eukaryotic endomembrane system likely aroseviaparalogous expansion of genes encoding proteins specifying organelle identity, coat complexes and government of fusion specificity. While the majority of these gene families were established by the time of the last eukaryotic common ancestor (LECA), subsequent evolutionary events molded these systems, likely reflecting adaptations retained for increased fitness. As well as sequence evolution, these adaptations include loss of otherwise canonical subunits, emergence of lineage-specific proteins and paralog expansion. The exocyst complex is involved in late exocytosis, and possibly additional pathways, and is a member of the complexes associated with tethering containing helical rods (CATCHR) tethering complex family, which includes conserved oligomeric Golgi (COG), homotypic fusion and vacuole protein sorting (HOPS), class C core vacuole/endosome tethering (CORVET) and others. The exocyst is integrated into a complex GTPase signaling network in animals, fungi and other lineages. Prompted by discovery of Exo99, a non-canonical subunit in the excavate protistTrypanosoma brucei,and significantly increased genome sequence data, we examined evolution of the exocyst.Methods:We examined evolution of the exocyst by comparative genomics, phylogenetics and structure prediction.Results:The exocyst is highly conserved, but with substantial losses of subunits in the Apicomplexa and expansions in Streptophyta plants and Metazoa. Significantly, few taxa retain a partial complex, suggesting that, in the main, all subunits are required for functionality. Further, the ninth exocyst subunit Exo99 is specific to the Euglenozoa with a distinct architecture compared to the other subunits and which possibly represents a coat system.Conclusions:These data reveal a remarkable degree of evolutionary flexibility within the exocyst complex, suggesting significant diversity in exocytosis mechanisms.
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12
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Abstract
Morphological changes are critical for the virulence of a range of plant and human fungal pathogens.
Candida albicans is a major human fungal pathogen whose ability to switch between different morphological states is associated with its adaptability and pathogenicity. In particular,
C. albicans can switch from an oval yeast form to a filamentous hyphal form, which is characteristic of filamentous fungi. What mechanisms underlie hyphal growth and how are they affected by environmental stimuli from the host or resident microbiota? These questions are the focus of intensive research, as understanding
C. albicans hyphal growth has broad implications for cell biological and medical research.
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Affiliation(s)
- Robert A Arkowitz
- Université Côte d'Azur, CNRS, Inserm, Institute of Biology Valrose, Parc Valrose, Nice, France
| | - Martine Bassilana
- Université Côte d'Azur, CNRS, Inserm, Institute of Biology Valrose, Parc Valrose, Nice, France
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13
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Meca J, Massoni-Laporte A, Martinez D, Sartorel E, Loquet A, Habenstein B, McCusker D. Avidity-driven polarity establishment via multivalent lipid-GTPase module interactions. EMBO J 2018; 38:embj.201899652. [PMID: 30559330 DOI: 10.15252/embj.201899652] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 10/26/2018] [Accepted: 11/02/2018] [Indexed: 12/17/2022] Open
Abstract
While Rho GTPases are indispensible regulators of cellular polarity, the mechanisms underlying their anisotropic activation at membranes have been elusive. Using the budding yeast Cdc42 GTPase module, which includes a guanine nucleotide exchange factor (GEF) Cdc24 and the scaffold Bem1, we find that avidity generated via multivalent anionic lipid interactions is a critical mechanistic constituent of polarity establishment. We identify basic cluster (BC) motifs in Bem1 that drive the interaction of the scaffold-GEF complex with anionic lipids at the cell pole. This interaction appears to influence lipid acyl chain ordering, thus regulating membrane rigidity and feedback between Cdc42 and the membrane environment. Sequential mutation of the Bem1 BC motifs, PX domain, and the PH domain of Cdc24 lead to a progressive loss of cellular polarity stemming from defective Cdc42 nanoclustering on the plasma membrane and perturbed signaling. Our work demonstrates the importance of avidity via multivalent anionic lipid interactions in the spatial control of GTPase activation.
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Affiliation(s)
- Julien Meca
- CNRS, UMR 5095, European Institute of Chemistry and Biology, University of Bordeaux, Pessac, France
| | - Aurélie Massoni-Laporte
- CNRS, UMR 5095, European Institute of Chemistry and Biology, University of Bordeaux, Pessac, France
| | - Denis Martinez
- CNRS, UMR 5248, European Institute of Chemistry and Biology, University of Bordeaux, Pessac, France
| | - Elodie Sartorel
- CNRS, UMR 5095, European Institute of Chemistry and Biology, University of Bordeaux, Pessac, France
| | - Antoine Loquet
- CNRS, UMR 5248, European Institute of Chemistry and Biology, University of Bordeaux, Pessac, France
| | - Birgit Habenstein
- CNRS, UMR 5248, European Institute of Chemistry and Biology, University of Bordeaux, Pessac, France
| | - Derek McCusker
- CNRS, UMR 5095, European Institute of Chemistry and Biology, University of Bordeaux, Pessac, France
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14
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Sartorel E, Ünlü C, Jose M, Massoni-Laporte A, Meca J, Sibarita JB, McCusker D. Phosphatidylserine and GTPase activation control Cdc42 nanoclustering to counter dissipative diffusion. Mol Biol Cell 2018; 29:1299-1310. [PMID: 29668348 PMCID: PMC5994902 DOI: 10.1091/mbc.e18-01-0051] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The anisotropic organization of plasma membrane constituents is indicative of mechanisms that drive the membrane away from equilibrium. However, defining these mechanisms is challenging due to the short spatiotemporal scales at which diffusion operates. Here, we use high-density single protein tracking combined with photoactivation localization microscopy (sptPALM) to monitor Cdc42 in budding yeast, a system in which Cdc42 exhibits anisotropic organization. Cdc42 exhibited reduced mobility at the cell pole, where it was organized in nanoclusters. The Cdc42 nanoclusters were larger at the cell pole than those observed elsewhere in the cell. These features were exacerbated in cells expressing Cdc42-GTP, and were dependent on the scaffold Bem1, which contributed to the range of mobility and nanocluster size exhibited by Cdc42. The lipid environment, in particular phosphatidylserine levels, also played a role in regulating Cdc42 nanoclustering. These studies reveal how the mobility of a Rho GTPase is controlled to counter the depletive effects of diffusion, thus stabilizing Cdc42 on the plasma membrane and sustaining cell polarity.
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Affiliation(s)
- Elodie Sartorel
- Université Bordeaux, CNRS, UMR 5095, European Institute of Chemistry and Biology, Pessac 33607, France
| | - Caner Ünlü
- Université Bordeaux, CNRS, UMR 5095, European Institute of Chemistry and Biology, Pessac 33607, France
| | - Mini Jose
- Université Bordeaux, CNRS, UMR 5095, European Institute of Chemistry and Biology, Pessac 33607, France
| | - Aurélie Massoni-Laporte
- Université Bordeaux, CNRS, UMR 5095, European Institute of Chemistry and Biology, Pessac 33607, France
| | - Julien Meca
- Université Bordeaux, CNRS, UMR 5095, European Institute of Chemistry and Biology, Pessac 33607, France
| | - Jean-Baptiste Sibarita
- Université Bordeaux, Institut Interdisciplinaire de Neurosciences, Bordeaux 33077, France.,CNRS UMR 5297, Institut Interdisciplinaire de Neurosciences, Bordeaux 33077, France
| | - Derek McCusker
- Université Bordeaux, CNRS, UMR 5095, European Institute of Chemistry and Biology, Pessac 33607, France
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15
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Polgar N, Fogelgren B. Regulation of Cell Polarity by Exocyst-Mediated Trafficking. Cold Spring Harb Perspect Biol 2018; 10:cshperspect.a031401. [PMID: 28264817 DOI: 10.1101/cshperspect.a031401] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
One requirement for establishing polarity within a cell is the asymmetric trafficking of intracellular vesicles to the plasma membrane. This tightly regulated process creates spatial and temporal differences in both plasma membrane composition and the membrane-associated proteome. Asymmetric membrane trafficking is also a critical mechanism to regulate cell differentiation, signaling, and physiology. Many eukaryotic cell types use the eight-protein exocyst complex to orchestrate polarized vesicle trafficking to certain membrane locales. Members of the exocyst were originally discovered in yeast while screening for proteins required for the delivery of secretory vesicles to the budding daughter cell. The same eight exocyst genes are conserved in mammals, in which the specifics of exocyst-mediated trafficking are highly cell-type-dependent. Some exocyst members bind to certain Rab GTPases on intracellular vesicles, whereas others localize to the plasma membrane at the site of exocytosis. Assembly of the exocyst holocomplex is responsible for tethering these vesicles to the plasma membrane before their soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE)-mediated exocytosis. In this review, we will focus on the role and regulation of the exocyst complex in targeted vesicular trafficking as related to the establishment and maintenance of cellular polarity. We will contrast exocyst function in apicobasal epithelial polarity versus front-back mesenchymal polarity, and the dynamic regulation of exocyst-mediated trafficking during cell phenotype transitions.
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Affiliation(s)
- Noemi Polgar
- Department of Anatomy, Biochemistry and Physiology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii 96813
| | - Ben Fogelgren
- Department of Anatomy, Biochemistry and Physiology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii 96813
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16
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Shin SW, Vogt EJ, Jimenez-Movilla M, Baibakov B, Dean J. Cytoplasmic cleavage of DPPA3 is required for intracellular trafficking and cleavage-stage development in mice. Nat Commun 2017; 8:1643. [PMID: 29158485 PMCID: PMC5696369 DOI: 10.1038/s41467-017-01387-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Accepted: 09/05/2017] [Indexed: 01/06/2023] Open
Abstract
Degradation of maternal proteins by the ubiquitin-proteasome system (UPS) accompanies the maternal-to-zygotic transition. DPPA3/Stella/PGC7, encoded by a maternal effect gene, is present in the nucleus and cytoplasm of zygotes and has been associated with protecting the female pronucleus from TET3-mediated demethylation. We now report that cytoplasmic DPPA3 is partially cleaved by the ubiquitin-proteasome system and an N-terminus fragment remains in the cytoplasm where it associates with early and re-cycling endosomes. If DPPA3 is absent or if cleavage is prevented, multiple vesicles coalesce/aggregate and markers of lysosomes are decreased. Fertilized eggs develop poorly into blastocysts, which results in significantly decreased fecundity of Dppa3 R60A transgenic mice. This phenocopies aspects of Lamp1/2 knockdowns and Dppa3 KO embryos can be partially rescued in vitro by DPPA31-60 and to a lesser extent by LAMP1/2. Thus, the N-terminus of DPPA3 has a significant role in cytoplasmic vesicular trafficking in addition to its previously reported nuclear function.
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Affiliation(s)
- Seung-Wook Shin
- Laboratory of Cellular and Developmental Biology, NIDDK, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Edgar John Vogt
- Laboratory of Cellular and Developmental Biology, NIDDK, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Maria Jimenez-Movilla
- Department of Cell Biology and Histology, Medical School, University of Murcia, IMIB, 30100, Murcia, Spain
| | - Boris Baibakov
- Laboratory of Cellular and Developmental Biology, NIDDK, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Jurrien Dean
- Laboratory of Cellular and Developmental Biology, NIDDK, National Institutes of Health, Bethesda, MD, 20892, USA.
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17
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Mayers JR, Hu T, Wang C, Cárdenas JJ, Tan Y, Pan J, Bednarek SY. SCD1 and SCD2 Form a Complex That Functions with the Exocyst and RabE1 in Exocytosis and Cytokinesis. THE PLANT CELL 2017; 29:2610-2625. [PMID: 28970336 PMCID: PMC5774579 DOI: 10.1105/tpc.17.00409] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 09/12/2017] [Accepted: 09/26/2017] [Indexed: 05/21/2023]
Abstract
Although exocytosis is critical for the proper trafficking of materials to the plasma membrane, relatively little is known about the mechanistic details of post-Golgi trafficking in plants. Here, we demonstrate that the DENN (Differentially Expressed in Normal and Neoplastic cells) domain protein STOMATAL CYTOKINESIS DEFECTIVE1 (SCD1) and SCD2 form a previously unknown protein complex, the SCD complex, that functionally interacts with subunits of the exocyst complex and the RabE1 family of GTPases in Arabidopsis thaliana Consistent with a role in post-Golgi trafficking, scd1 and scd2 mutants display defects in exocytosis and recycling of PIN2-GFP. Perturbation of exocytosis using the small molecule Endosidin2 results in growth inhibition and PIN2-GFP trafficking defects in scd1 and scd2 mutants. In addition to the exocyst, the SCD complex binds in a nucleotide state-specific manner with Sec4p/Rab8-related RabE1 GTPases and overexpression of wild-type RabE1 rescues scd1 temperature-sensitive mutants. Furthermore, SCD1 colocalizes with the exocyst subunit, SEC15B, and RabE1 at the cell plate and in distinct punctae at or near the plasma membrane. Our findings reveal a mechanism for plant exocytosis, through the identification and characterization of a protein interaction network that includes the SCD complex, RabE1, and the exocyst.
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Affiliation(s)
| | - Tianwei Hu
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Chao Wang
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
| | - Jessica J Cárdenas
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706
| | - Yuqi Tan
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706
| | - Jianwei Pan
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
- College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004, China
| | - Sebastian Y Bednarek
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706
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18
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Masgrau A, Battola A, Sanmartin T, Pryszcz LP, Gabaldón T, Mendoza M. Distinct roles of the polarity factors Boi1 and Boi2 in the control of exocytosis and abscission in budding yeast. Mol Biol Cell 2017; 28:3082-3094. [PMID: 28904204 PMCID: PMC5662264 DOI: 10.1091/mbc.e17-06-0404] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Revised: 08/31/2017] [Accepted: 09/06/2017] [Indexed: 01/09/2023] Open
Abstract
The budding yeast cortical proteins Boi1 and Boi2 were previously implicated in polarized growth and in inhibition of cytokinesis as part of the NoCut abscission checkpoint. This report establishes an essential role of Boi1 and Boi2 in vesicle exocytosis during bud growth, whereas Boi2 (but not Boi1) is required for abscission inhibition. Boi1 and Boi2 (Boi1/2) are budding yeast plasma membrane proteins that function in polarized growth, and in cytokinesis inhibition in response to chromosome bridges via the NoCut abscission checkpoint. How Boi1/2 act in these two distinct processes is not understood. We demonstrate that Boi1/2 are required for a late step in the fusion of secretory vesicles with the plasma membrane of the growing bud. Cells lacking Boi1/2 accumulate secretory vesicles and are defective in bud growth. In contrast, Boi2 is specifically required for abscission inhibition in cells with chromatin bridges. The SH3 domain of Boi2, which is dispensable for bud growth and targets Boi2 to the site of abscission, is necessary and sufficient for abscission inhibition. Gain of function of the exocyst, a conserved protein complex involved in tethering of exocytic vesicles to the plasma membrane, rescued secretion and bud growth defects in boi mutant cells, and abrogated NoCut checkpoint function. Thus Boi2 functions redundantly with Boi1 to promote the fusion of secretory vesicles with the plasma membrane at sites of polarized growth, and acts as an abscission inhibitor during cytokinesis in response to chromatin bridges.
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Affiliation(s)
- Aina Masgrau
- Centre for Genomic Regulation, The Barcelona Institute of Science and Technology, 08003 Barcelona, Spain.,Universitat Pompeu Fabra, 08003 Barcelona, Spain
| | - Andrea Battola
- Centre for Genomic Regulation, The Barcelona Institute of Science and Technology, 08003 Barcelona, Spain.,Universitat Pompeu Fabra, 08003 Barcelona, Spain
| | - Trinidad Sanmartin
- Centre for Genomic Regulation, The Barcelona Institute of Science and Technology, 08003 Barcelona, Spain.,Universitat Pompeu Fabra, 08003 Barcelona, Spain
| | - Leszek P Pryszcz
- Centre for Genomic Regulation, The Barcelona Institute of Science and Technology, 08003 Barcelona, Spain.,Universitat Pompeu Fabra, 08003 Barcelona, Spain
| | - Toni Gabaldón
- Centre for Genomic Regulation, The Barcelona Institute of Science and Technology, 08003 Barcelona, Spain.,Universitat Pompeu Fabra, 08003 Barcelona, Spain.,Institució Catalana de Recerca i Estudis Avançats, 08010 Barcelona, Spain
| | - Manuel Mendoza
- Centre for Genomic Regulation, The Barcelona Institute of Science and Technology, 08003 Barcelona, Spain .,Universitat Pompeu Fabra, 08003 Barcelona, Spain
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19
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Estravís M, Rincón SA, Portales E, Pérez P, Santos B. Cdc42 activation state affects its localization and protein levels in fission yeast. MICROBIOLOGY-SGM 2017; 163:1156-1166. [PMID: 28742002 DOI: 10.1099/mic.0.000503] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Rho GTPases control polarized cell growth and are well-known regulators of exocytic and endocytic processes. Cdc42 is an essential GTPase, conserved from yeast to humans, that is critical for cell polarization. Cdc42 is negatively regulated by the GTPase-activating proteins (GAPs) and the GDP dissociation inhibitors (GDIs), and positively regulated by guanine nucleotide exchange factors (GEFs). Cdc42 GTPase can be found in a GTP- or GDP-bound state, which determines the ability to bind downstream effector proteins and activate signalling pathways. Only GTP-bound Cdc42 is active. In this study we have analysed the localization of the different nucleotide-bound states of Cdc42 in Schizosaccharomyces pombe: the wild-type Cdc42 protein that cycles between an active and inactive form, the Cdc42G12V form that is permanently bound to GTP and the Cdc42T17N form that is constitutively inactive. Our results indicate that Cdc42 localizes to several membrane compartments in the cell and this localization is mediated by its C-terminal prenylation. Constitutively active Cdc42 localizes mainly to the plasma membrane and concentrates at the growing tips where it is considerably less dynamic than wild-type or GDP-bound Cdc42. Additionally we show that the activation state of Cdc42 also participates in the regulation of its protein levels mediated by endocytosis and by the exocyst complex.
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Affiliation(s)
- Miguel Estravís
- Instituto de Biología Funcional y Genómica (IBFG), Consejo Superior de Investigaciones Científicas, University of Salamanca, 37007 Salamanca, Spain
| | - Sergio Antonio Rincón
- Instituto de Biología Funcional y Genómica (IBFG), Consejo Superior de Investigaciones Científicas, University of Salamanca, 37007 Salamanca, Spain.,Present address: Institut Curie, Centre de Recherche, PSL Research University, CNRS UMR144, F-75248 Paris, France
| | - Elvira Portales
- Instituto de Biología Funcional y Genómica (IBFG), Consejo Superior de Investigaciones Científicas, University of Salamanca, 37007 Salamanca, Spain
| | - Pilar Pérez
- Instituto de Biología Funcional y Genómica (IBFG), Consejo Superior de Investigaciones Científicas, University of Salamanca, 37007 Salamanca, Spain
| | - Beatriz Santos
- Instituto de Biología Funcional y Genómica (IBFG), Consejo Superior de Investigaciones Científicas, University of Salamanca, 37007 Salamanca, Spain.,Departamento de Microbiología y Genética, University of Salamanca, 37007 Salamanca, Spain
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20
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MoEnd3 regulates appressorium formation and virulence through mediating endocytosis in rice blast fungus Magnaporthe oryzae. PLoS Pathog 2017. [PMID: 28628655 PMCID: PMC5491321 DOI: 10.1371/journal.ppat.1006449] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Eukaryotic cells respond to environmental stimuli when cell surface receptors are bound by environmental ligands. The binding initiates a signal transduction cascade that results in the appropriate intracellular responses. Studies have shown that endocytosis is critical for receptor internalization and signaling activation. In the rice blast fungus Magnaporthe oryzae, a non-canonical G-protein coupled receptor, Pth11, and membrane sensors MoMsb2 and MoSho1 are thought to function upstream of G-protein/cAMP signaling and the Pmk1 MAPK pathway to regulate appressorium formation and pathogenesis. However, little is known about how these receptors or sensors are internalized and transported into intracellular compartments. We found that the MoEnd3 protein is important for endocytic transport and that the ΔMoend3 mutant exhibited defects in efficient internalization of Pth11 and MoSho1. The ΔMoend3 mutant was also defective in Pmk1 phosphorylation, autophagy, appressorium formation and function. Intriguingly, restoring Pmk1 phosphorylation levels in ΔMoend3 suppressed most of these defects. Moreover, we demonstrated that MoEnd3 is subject to regulation by MoArk1 through protein phosphorylation. We also found that MoEnd3 has additional functions in facilitating the secretion of effectors, including Avr-Pia and AvrPiz-t that suppress rice immunity. Taken together, our findings suggest that MoEnd3 plays a critical role in mediating receptor endocytosis that is critical for the signal transduction-regulated development and virulence of M. oryzae.
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21
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Abstract
The eukaryotic actin cytoskeleton is a highly dynamic framework that is involved in many biological processes, such as cell growth, division, morphology, and motility. G-actin polymerizes into microfilaments that associate into bundles, patches, and networks, which, in turn, organize into higher order structures that are fundamental for the course of important physiological events. Actin rings are an example for such higher order actin entities, but this term represents an actually diverse set of subcellular structures that are involved in various processes. This review especially sheds light on a crucial type of non-constricting ring-like actin networks, and categorizes them under the term 'actin fringe'. These 'actin fringes' are visualized as highly dynamic and yet steady structures in the tip of various polarized growing cells. The present comprehensive overview compares the actin fringe characteristics of rapidly elongating pollen tubes with several related actin arrays in other cell types of diverse species. The current state of knowledge about various actin fringe functions is summarized, and the key role of this structure in the polar growth process is discussed.
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Affiliation(s)
- Octavian O H Stephan
- Department of Biology, Friedrich-Alexander University of Erlangen-Nuremberg, Erlangen, Bavaria 91058, Germany
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22
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Rapali P, Mitteau R, Braun C, Massoni-Laporte A, Ünlü C, Bataille L, Arramon FS, Gygi SP, McCusker D. Scaffold-mediated gating of Cdc42 signalling flux. eLife 2017; 6. [PMID: 28304276 PMCID: PMC5386590 DOI: 10.7554/elife.25257] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Accepted: 03/15/2017] [Indexed: 12/03/2022] Open
Abstract
Scaffold proteins modulate signalling pathway activity spatially and temporally. In budding yeast, the scaffold Bem1 contributes to polarity axis establishment by regulating the GTPase Cdc42. Although different models have been proposed for Bem1 function, there is little direct evidence for an underlying mechanism. Here, we find that Bem1 directly augments the guanine exchange factor (GEF) activity of Cdc24. Bem1 also increases GEF phosphorylation by the p21-activated kinase (PAK), Cla4. Phosphorylation abrogates the scaffold-dependent stimulation of GEF activity, rendering Cdc24 insensitive to additional Bem1. Thus, Bem1 stimulates GEF activity in a reversible fashion, contributing to signalling flux through Cdc42. The contribution of Bem1 to GTPase dynamics was borne-out by in vivo imaging: active Cdc42 was enriched at the cell pole in hypophosphorylated cdc24 mutants, while hyperphosphorylated cdc24 mutants that were resistant to scaffold stimulation displayed a deficit in active Cdc42 at the pole. These findings illustrate the self-regulatory properties that scaffold proteins confer on signalling pathways. DOI:http://dx.doi.org/10.7554/eLife.25257.001
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Affiliation(s)
- Péter Rapali
- University of Bordeaux, CNRS, European Institute of Chemistry and Biology, IBGC, UMR 5095, Pessac, France
| | - Romain Mitteau
- University of Bordeaux, CNRS, European Institute of Chemistry and Biology, IBGC, UMR 5095, Pessac, France
| | - Craig Braun
- Department of Cell Biology, Harvard Medical School, Boston, United States
| | - Aurèlie Massoni-Laporte
- University of Bordeaux, CNRS, European Institute of Chemistry and Biology, IBGC, UMR 5095, Pessac, France
| | - Caner Ünlü
- University of Bordeaux, CNRS, European Institute of Chemistry and Biology, IBGC, UMR 5095, Pessac, France
| | - Laure Bataille
- University of Bordeaux, CNRS, European Institute of Chemistry and Biology, IBGC, UMR 5095, Pessac, France
| | - Floriane Saint Arramon
- University of Bordeaux, CNRS, European Institute of Chemistry and Biology, IBGC, UMR 5095, Pessac, France
| | - Steven P Gygi
- Department of Cell Biology, Harvard Medical School, Boston, United States
| | - Derek McCusker
- University of Bordeaux, CNRS, European Institute of Chemistry and Biology, IBGC, UMR 5095, Pessac, France
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23
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Sekereš J, Pejchar P, Šantrůček J, Vukašinović N, Žárský V, Potocký M. Analysis of Exocyst Subunit EXO70 Family Reveals Distinct Membrane Polar Domains in Tobacco Pollen Tubes. PLANT PHYSIOLOGY 2017; 173:1659-1675. [PMID: 28082718 PMCID: PMC5338673 DOI: 10.1104/pp.16.01709] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Accepted: 01/10/2017] [Indexed: 05/05/2023]
Abstract
The vesicle-tethering complex exocyst is one of the crucial cell polarity regulators. The EXO70 subunit is required for the targeting of the complex and is represented by many isoforms in angiosperm plant cells. This diversity could be partly responsible for the establishment and maintenance of membrane domains with different composition. To address this hypothesis, we employed the growing pollen tube, a well-established cell polarity model system, and performed large-scale expression, localization, and functional analysis of tobacco (Nicotiana tabacum) EXO70 isoforms. Various isoforms localized to different regions of the pollen tube plasma membrane, apical vesicle-rich inverted cone region, nucleus, and cytoplasm. The overexpression of major pollen-expressed EXO70 isoforms resulted in growth arrest and characteristic phenotypic deviations of tip swelling and apical invaginations. NtEXO70A1a and NtEXO70B1 occupied two distinct and mutually exclusive plasma membrane domains. Both isoforms partly colocalized with the exocyst subunit NtSEC3a at the plasma membrane, possibly forming different exocyst complex subpopulations. NtEXO70A1a localized to the small area previously characterized as the site of exocytosis in the tobacco pollen tube, while NtEXO70B1 surprisingly colocalized with the zone of clathrin-mediated endocytosis. Both NtEXO70A1a and NtEXO70B1 colocalized to different degrees with markers for the anionic signaling phospholipids phosphatidylinositol 4,5-bisphosphate and phosphatidic acid. In contrast, members of the EXO70 C class, which are specifically expressed in tip-growing cells, exhibited exocytosis-related functional effects in pollen tubes despite the absence of apparent plasma membrane localization. Taken together, our data support the existence of multiple membrane-trafficking domains regulated by different EXO70-containing exocyst complexes within a single cell.
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Affiliation(s)
- Juraj Sekereš
- Institute of Experimental Botany, Czech Academy of Sciences, Prague 6, Czech Republic (J.S., P.P., N.V., V.Ž., M.P.)
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague 2, Czech Republic (J.S., V.Ž.); and
- Department of Biochemistry and Microbiology, University of Chemistry and Technology, Prague 6, Czech Republic (J.Š.)
| | - Přemysl Pejchar
- Institute of Experimental Botany, Czech Academy of Sciences, Prague 6, Czech Republic (J.S., P.P., N.V., V.Ž., M.P.)
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague 2, Czech Republic (J.S., V.Ž.); and
- Department of Biochemistry and Microbiology, University of Chemistry and Technology, Prague 6, Czech Republic (J.Š.)
| | - Jiří Šantrůček
- Institute of Experimental Botany, Czech Academy of Sciences, Prague 6, Czech Republic (J.S., P.P., N.V., V.Ž., M.P.)
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague 2, Czech Republic (J.S., V.Ž.); and
- Department of Biochemistry and Microbiology, University of Chemistry and Technology, Prague 6, Czech Republic (J.Š.)
| | - Nemanja Vukašinović
- Institute of Experimental Botany, Czech Academy of Sciences, Prague 6, Czech Republic (J.S., P.P., N.V., V.Ž., M.P.)
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague 2, Czech Republic (J.S., V.Ž.); and
- Department of Biochemistry and Microbiology, University of Chemistry and Technology, Prague 6, Czech Republic (J.Š.)
| | - Viktor Žárský
- Institute of Experimental Botany, Czech Academy of Sciences, Prague 6, Czech Republic (J.S., P.P., N.V., V.Ž., M.P.)
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague 2, Czech Republic (J.S., V.Ž.); and
- Department of Biochemistry and Microbiology, University of Chemistry and Technology, Prague 6, Czech Republic (J.Š.)
| | - Martin Potocký
- Institute of Experimental Botany, Czech Academy of Sciences, Prague 6, Czech Republic (J.S., P.P., N.V., V.Ž., M.P.);
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague 2, Czech Republic (J.S., V.Ž.); and
- Department of Biochemistry and Microbiology, University of Chemistry and Technology, Prague 6, Czech Republic (J.Š.)
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24
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Labbaoui H, Bogliolo S, Ghugtyal V, Solis NV, Filler SG, Arkowitz RA, Bassilana M. Role of Arf GTPases in fungal morphogenesis and virulence. PLoS Pathog 2017; 13:e1006205. [PMID: 28192532 PMCID: PMC5325608 DOI: 10.1371/journal.ppat.1006205] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 02/24/2017] [Accepted: 01/29/2017] [Indexed: 12/30/2022] Open
Abstract
Virulence of the human fungal pathogen Candida albicans depends on the switch from budding to filamentous growth, which requires sustained membrane traffic and polarized growth. In many organisms, small GTPases of the Arf (ADP-ribosylation factor) family regulate membrane/protein trafficking, yet little is known about their role in fungal filamentous growth. To investigate these GTPases in C. albicans, we generated loss of function mutants in all 3 Arf proteins, Arf1-Arf3, and 2 Arf-like proteins, Arl1 and Arl3. Our results indicate that of these proteins, Arf2 is required for viability and sensitivity to antifungal drugs. Repressible ARF2 expression results in defects in filamentous growth, cell wall integrity and virulence, likely due to alteration of the Golgi. Arl1 is also required for invasive filamentous growth and, although arl1/arl1 cells can initiate hyphal growth, hyphae are substantially shorter than that of the wild-type, due to the inability of this mutant to maintain hyphal growth at a single site. We show that this defect does not result from an alteration of phospholipid distribution and is unlikely to result from the sole Golgin Imh1 mislocalization, as Imh1 is not required for invasive filamentous growth. Rather, our results suggest that the arl1/arl1 hyphal growth defect results from increased secretion in this mutant. Strikingly, the arl1/arl1 mutant is drastically reduced in virulence during oropharyngeal candidiasis. Together, our results highlight the importance of Arl1 and Arf2 as key regulators of hyphal growth and virulence in C. albicans and identify a unique function of Arl1 in secretion.
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Affiliation(s)
- Hayet Labbaoui
- Université Côte d’Azur, CNRS, INSERM, iBV, Parc Valrose, Nice, France
| | | | - Vikram Ghugtyal
- Université Côte d’Azur, CNRS, INSERM, iBV, Parc Valrose, Nice, France
| | - Norma V. Solis
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA, United States of America
| | - Scott G. Filler
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA, United States of America
| | | | - Martine Bassilana
- Université Côte d’Azur, CNRS, INSERM, iBV, Parc Valrose, Nice, France
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25
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Yabuki Y, Katayama M, Kodama Y, Sakamoto A, Yatsuhashi A, Funato K, Mizuta K. Arp2/3 complex and Mps3 are required for regulation of ribosome biosynthesis in the secretory stress response. Yeast 2017; 34:155-163. [PMID: 27862269 DOI: 10.1002/yea.3221] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 10/18/2016] [Accepted: 11/03/2016] [Indexed: 11/11/2022] Open
Abstract
Secretory defects cause transcriptional repression of ribosome biogenesis in Saccharomyces cerevisiae. However, the molecular mechanism underlying secretory defect-induced transcriptional repression of ribosome biogenesis remains to be fully elucidated. In this study, we demonstrated that the Arp2/3 complex was required for reduction of ribosome protein gene expression in response to defective secretion by addition of tunicamycin. Two cmd1 mutants, cmd1-228 and cmd1-239 that cause mislocalization of calmodulin and defective mitotic spindle formation, respectively, failed to interact with Arc35, a component of the Arp2/3 complex. These mutants also caused defects in the reduction of ribosome protein gene expression induced by secretory blockade. A mutation in TUB4 (tub4-1), whose product has an essential function in microtubule organization, showed a similar response. In addition, we showed that the response to a secretory defect required SUN protein Mps3, which was localized at the nuclear envelope and involved in spindle pole body assembly. These results suggest that the Arp2/3 complex is required to transmit signals resulting from secretory blockade, and that the spindle pole body functions as a transit point from cytoplasm to Mps3 at the nuclear envelope. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Yukari Yabuki
- Department of Biofunctional Science and Technology, Graduate School of Biosphere Science, Hiroshima University, Kagamiyama 1-4-4, Higashi-Hiroshima, 739-8528, Japan
| | - Masako Katayama
- Department of Biofunctional Science and Technology, Graduate School of Biosphere Science, Hiroshima University, Kagamiyama 1-4-4, Higashi-Hiroshima, 739-8528, Japan
| | - Yushi Kodama
- Department of Biofunctional Science and Technology, Graduate School of Biosphere Science, Hiroshima University, Kagamiyama 1-4-4, Higashi-Hiroshima, 739-8528, Japan
| | - Akiko Sakamoto
- Department of Biofunctional Science and Technology, Graduate School of Biosphere Science, Hiroshima University, Kagamiyama 1-4-4, Higashi-Hiroshima, 739-8528, Japan
| | - Ayumi Yatsuhashi
- Department of Biofunctional Science and Technology, Graduate School of Biosphere Science, Hiroshima University, Kagamiyama 1-4-4, Higashi-Hiroshima, 739-8528, Japan
| | - Kouichi Funato
- Department of Biofunctional Science and Technology, Graduate School of Biosphere Science, Hiroshima University, Kagamiyama 1-4-4, Higashi-Hiroshima, 739-8528, Japan
| | - Keiko Mizuta
- Department of Biofunctional Science and Technology, Graduate School of Biosphere Science, Hiroshima University, Kagamiyama 1-4-4, Higashi-Hiroshima, 739-8528, Japan
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26
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Internetwork competition for monomers governs actin cytoskeleton organization. Nat Rev Mol Cell Biol 2016; 17:799-810. [PMID: 27625321 DOI: 10.1038/nrm.2016.106] [Citation(s) in RCA: 106] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Cells precisely control the formation of dynamic actin cytoskeleton networks to coordinate fundamental processes, including motility, division, endocytosis and polarization. To support these functions, actin filament networks must be assembled, maintained and disassembled at the correct time and place, and with proper filament organization and dynamics. Regulation of the extent of filament network assembly and of filament network organization has been largely attributed to the coordinated activation of actin assembly factors through signalling cascades. Here, we discuss an intriguing model in which actin monomer availability is limiting and competition between homeostatic actin cytoskeletal networks for actin monomers is an additional crucial regulatory mechanism that influences the density and size of different actin networks, thereby contributing to the organization of the cellular actin cytoskeleton.
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27
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Johansen J, Alfaro G, Beh CT. Polarized Exocytosis Induces Compensatory Endocytosis by Sec4p-Regulated Cortical Actin Polymerization. PLoS Biol 2016; 14:e1002534. [PMID: 27526190 PMCID: PMC4985162 DOI: 10.1371/journal.pbio.1002534] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Accepted: 07/21/2016] [Indexed: 11/18/2022] Open
Abstract
Polarized growth is maintained by both polarized exocytosis, which transports membrane components to specific locations on the cell cortex, and endocytosis, which retrieves these components before they can diffuse away. Despite functional links between these two transport pathways, they are generally considered to be separate events. Using live cell imaging, in vivo and in vitro protein binding assays, and in vitro pyrene-actin polymerization assays, we show that the yeast Rab GTPase Sec4p couples polarized exocytosis with cortical actin polymerization, which induces endocytosis. After polarized exocytosis to the plasma membrane, Sec4p binds Las17/Bee1p (yeast Wiskott-Aldrich Syndrome protein [WASp]) in a complex with Sla1p and Sla2p during actin patch assembly. Mutations that inactivate Sec4p, or its guanine nucleotide exchange factor (GEF) Sec2p, inhibit actin patch formation, whereas the activating sec4-Q79L mutation accelerates patch assembly. In vitro assays of Arp2/3-dependent actin polymerization established that GTPγS-Sec4p overrides Sla1p inhibition of Las17p-dependent actin nucleation. These results support a model in which Sec4p relocates along the plasma membrane from polarized sites of exocytic vesicle fusion to nascent sites of endocytosis. Activated Sec4p then promotes actin polymerization and triggers compensatory endocytosis, which controls surface expansion and kinetically refines cell polarization.
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Affiliation(s)
- Jesper Johansen
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Gabriel Alfaro
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Christopher T. Beh
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada
- Centre for Cell Biology, Development, and Disease, Simon Fraser University, Burnaby, British Columbia, Canada
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28
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Schröter S, Beckmann S, Schmitt HD. ER arrival sites for COPI vesicles localize to hotspots of membrane trafficking. EMBO J 2016; 35:1935-55. [PMID: 27440402 DOI: 10.15252/embj.201592873] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 06/21/2016] [Indexed: 11/09/2022] Open
Abstract
COPI-coated vesicles mediate retrograde membrane traffic from the cis-Golgi to the endoplasmic reticulum (ER) in all eukaryotic cells. However, it is still unknown whether COPI vesicles fuse everywhere or at specific sites with the ER membrane. Taking advantage of the circumstance that the vesicles still carry their coat when they arrive at the ER, we have visualized active ER arrival sites (ERAS) by monitoring contact between COPI coat components and the ER-resident Dsl tethering complex using bimolecular fluorescence complementation (BiFC). ERAS form punctate structures near Golgi compartments, clearly distinct from ER exit sites. Furthermore, ERAS are highly polarized in an actin and myosin V-dependent manner and are localized near hotspots of plasma membrane expansion. Genetic experiments suggest that the COPI•Dsl BiFC complexes recapitulate the physiological interaction between COPI and the Dsl complex and that COPI vesicles are mistargeted in dsl1 mutants. We conclude that the Dsl complex functions in confining COPI vesicle fusion sites.
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Affiliation(s)
- Saskia Schröter
- Department of Neurobiology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Sabrina Beckmann
- Department of Neurobiology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Hans Dieter Schmitt
- Department of Neurobiology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
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29
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Martin-Urdiroz M, Deeks MJ, Horton CG, Dawe HR, Jourdain I. The Exocyst Complex in Health and Disease. Front Cell Dev Biol 2016; 4:24. [PMID: 27148529 PMCID: PMC4828438 DOI: 10.3389/fcell.2016.00024] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Accepted: 03/11/2016] [Indexed: 01/23/2023] Open
Abstract
Exocytosis involves the fusion of intracellular secretory vesicles with the plasma membrane, thereby delivering integral membrane proteins to the cell surface and releasing material into the extracellular space. Importantly, exocytosis also provides a source of lipid moieties for membrane extension. The tethering of the secretory vesicle before docking and fusion with the plasma membrane is mediated by the exocyst complex, an evolutionary conserved octameric complex of proteins. Recent findings indicate that the exocyst complex also takes part in other intra-cellular processes besides secretion. These various functions seem to converge toward defining a direction of membrane growth in a range of systems from fungi to plants and from neurons to cilia. In this review we summarize the current knowledge of exocyst function in cell polarity, signaling and cell-cell communication and discuss implications for plant and animal health and disease.
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Affiliation(s)
| | - Michael J Deeks
- Biosciences, College of Life and Environmental Sciences, University of Exeter Exeter, UK
| | - Connor G Horton
- Biosciences, College of Life and Environmental Sciences, University of Exeter Exeter, UK
| | - Helen R Dawe
- Biosciences, College of Life and Environmental Sciences, University of Exeter Exeter, UK
| | - Isabelle Jourdain
- Biosciences, College of Life and Environmental Sciences, University of Exeter Exeter, UK
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30
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Derive N, Landmann C, Montembault E, Claverie MC, Pierre-Elies P, Goutte-Gattat D, Founounou N, McCusker D, Royou A. Bub3-BubR1-dependent sequestration of Cdc20Fizzy at DNA breaks facilitates the correct segregation of broken chromosomes. J Cell Biol 2016; 211:517-32. [PMID: 26553926 PMCID: PMC4639866 DOI: 10.1083/jcb.201504059] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
BubR1 depends on its association with Bub3 to localize on DNA breaks during mitosis, where it sequesters Cdc20Fizzy and induces the inhibition of the APC/C locally, promoting the faithful segregation of broken chromatids. The presence of DNA double-strand breaks during mitosis is particularly challenging for the cell, as it produces broken chromosomes lacking a centromere. This situation can cause genomic instability resulting from improper segregation of the broken fragments into daughter cells. We recently uncovered a process by which broken chromosomes are faithfully transmitted via the BubR1-dependent tethering of the two broken chromosome ends. However, the mechanisms underlying BubR1 recruitment and function on broken chromosomes were largely unknown. We show that BubR1 requires interaction with Bub3 to localize on the broken chromosome fragments and to mediate their proper segregation. We also find that Cdc20, a cofactor of the E3 ubiquitin ligase anaphase-promoting complex/cyclosome (APC/C), accumulates on DNA breaks in a BubR1 KEN box–dependent manner. A biosensor for APC/C activity demonstrates a BubR1-dependent local inhibition of APC/C around the segregating broken chromosome. We therefore propose that the Bub3–BubR1 complex on broken DNA inhibits the APC/C locally via the sequestration of Cdc20, thus promoting proper transmission of broken chromosomes.
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Affiliation(s)
- Nicolas Derive
- Université de Bordeaux, Institut Européen de Chimie et Biologie, Institut de Biochimie et Génétique Cellulaires, Unité Mixte de Recherche 5095, 33607 Pessac, France Centre National de la Recherche Scientifique, Institut Européen de Chimie et Biologie, Institut de Biochimie et Génétique Cellulaires, Unité Mixte de Recherche 5095, 33607 Pessac, France
| | - Cedric Landmann
- Université de Bordeaux, Institut Européen de Chimie et Biologie, Institut de Biochimie et Génétique Cellulaires, Unité Mixte de Recherche 5095, 33607 Pessac, France Centre National de la Recherche Scientifique, Institut Européen de Chimie et Biologie, Institut de Biochimie et Génétique Cellulaires, Unité Mixte de Recherche 5095, 33607 Pessac, France
| | - Emilie Montembault
- Université de Bordeaux, Institut Européen de Chimie et Biologie, Institut de Biochimie et Génétique Cellulaires, Unité Mixte de Recherche 5095, 33607 Pessac, France Centre National de la Recherche Scientifique, Institut Européen de Chimie et Biologie, Institut de Biochimie et Génétique Cellulaires, Unité Mixte de Recherche 5095, 33607 Pessac, France
| | - Marie-Charlotte Claverie
- Université de Bordeaux, Institut Européen de Chimie et Biologie, Institut de Biochimie et Génétique Cellulaires, Unité Mixte de Recherche 5095, 33607 Pessac, France Centre National de la Recherche Scientifique, Institut Européen de Chimie et Biologie, Institut de Biochimie et Génétique Cellulaires, Unité Mixte de Recherche 5095, 33607 Pessac, France
| | - Priscillia Pierre-Elies
- Université de Bordeaux, Institut Européen de Chimie et Biologie, Institut de Biochimie et Génétique Cellulaires, Unité Mixte de Recherche 5095, 33607 Pessac, France Centre National de la Recherche Scientifique, Institut Européen de Chimie et Biologie, Institut de Biochimie et Génétique Cellulaires, Unité Mixte de Recherche 5095, 33607 Pessac, France
| | - Damien Goutte-Gattat
- Université de Bordeaux, Institut Européen de Chimie et Biologie, Institut de Biochimie et Génétique Cellulaires, Unité Mixte de Recherche 5095, 33607 Pessac, France Centre National de la Recherche Scientifique, Institut Européen de Chimie et Biologie, Institut de Biochimie et Génétique Cellulaires, Unité Mixte de Recherche 5095, 33607 Pessac, France
| | - Nabila Founounou
- Université de Bordeaux, Institut Européen de Chimie et Biologie, Institut de Biochimie et Génétique Cellulaires, Unité Mixte de Recherche 5095, 33607 Pessac, France Centre National de la Recherche Scientifique, Institut Européen de Chimie et Biologie, Institut de Biochimie et Génétique Cellulaires, Unité Mixte de Recherche 5095, 33607 Pessac, France
| | - Derek McCusker
- Université de Bordeaux, Institut Européen de Chimie et Biologie, Institut de Biochimie et Génétique Cellulaires, Unité Mixte de Recherche 5095, 33607 Pessac, France Centre National de la Recherche Scientifique, Institut Européen de Chimie et Biologie, Institut de Biochimie et Génétique Cellulaires, Unité Mixte de Recherche 5095, 33607 Pessac, France
| | - Anne Royou
- Université de Bordeaux, Institut Européen de Chimie et Biologie, Institut de Biochimie et Génétique Cellulaires, Unité Mixte de Recherche 5095, 33607 Pessac, France Centre National de la Recherche Scientifique, Institut Européen de Chimie et Biologie, Institut de Biochimie et Génétique Cellulaires, Unité Mixte de Recherche 5095, 33607 Pessac, France
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31
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Gupta YK, Dagdas YF, Martinez-Rocha AL, Kershaw MJ, Littlejohn GR, Ryder LS, Sklenar J, Menke F, Talbot NJ. Septin-Dependent Assembly of the Exocyst Is Essential for Plant Infection by Magnaporthe oryzae. THE PLANT CELL 2015; 27:3277-89. [PMID: 26566920 PMCID: PMC4682301 DOI: 10.1105/tpc.15.00552] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Revised: 10/05/2015] [Accepted: 10/20/2015] [Indexed: 05/21/2023]
Abstract
Magnaporthe oryzae is the causal agent of rice blast disease, the most devastating disease of cultivated rice (Oryza sativa) and a continuing threat to global food security. To cause disease, the fungus elaborates a specialized infection cell called an appressorium, which breaches the cuticle of the rice leaf, allowing the fungus entry to plant tissue. Here, we show that the exocyst complex localizes to the tips of growing hyphae during vegetative growth, ahead of the Spitzenkörper, and is required for polarized exocytosis. However, during infection-related development, the exocyst specifically assembles in the appressorium at the point of plant infection. The exocyst components Sec3, Sec5, Sec6, Sec8, and Sec15, and exocyst complex proteins Exo70 and Exo84 localize specifically in a ring formation at the appressorium pore. Targeted gene deletion, or conditional mutation, of genes encoding exocyst components leads to impaired plant infection. We demonstrate that organization of the exocyst complex at the appressorium pore is a septin-dependent process, which also requires regulated synthesis of reactive oxygen species by the NoxR-dependent Nox2 NADPH oxidase complex. We conclude that septin-mediated assembly of the exocyst is necessary for appressorium repolarization and host cell invasion.
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Affiliation(s)
- Yogesh K Gupta
- School of Biosciences, University of Exeter, Exeter EX4 4QD, United Kingdom The Sainsbury Laboratory, Norwich NR4 7UH, United Kingdom
| | - Yasin F Dagdas
- School of Biosciences, University of Exeter, Exeter EX4 4QD, United Kingdom The Sainsbury Laboratory, Norwich NR4 7UH, United Kingdom
| | | | - Michael J Kershaw
- School of Biosciences, University of Exeter, Exeter EX4 4QD, United Kingdom
| | | | - Lauren S Ryder
- School of Biosciences, University of Exeter, Exeter EX4 4QD, United Kingdom
| | - Jan Sklenar
- The Sainsbury Laboratory, Norwich NR4 7UH, United Kingdom
| | - Frank Menke
- The Sainsbury Laboratory, Norwich NR4 7UH, United Kingdom
| | - Nicholas J Talbot
- School of Biosciences, University of Exeter, Exeter EX4 4QD, United Kingdom
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32
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Malhó R, Serrazina S, Saavedra L, Dias FV, Ul-Rehman R. Ion and lipid signaling in apical growth-a dynamic machinery responding to extracellular cues. FRONTIERS IN PLANT SCIENCE 2015; 6:816. [PMID: 26500662 PMCID: PMC4594336 DOI: 10.3389/fpls.2015.00816] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 09/18/2015] [Indexed: 05/07/2023]
Abstract
Apical cell growth seems to have independently evolved throughout the major lineages of life. To a certain extent, so does our body of knowledge on the mechanisms regulating this morphogenetic process. Studies on pollen tubes, root hairs, rhizoids, fungal hyphae, even nerve cells, have highlighted tissue and cell specificities but also common regulatory characteristics (e.g., ions, proteins, phospholipids) that our focused research sometimes failed to grasp. The working hypothesis to test how apical cell growth is established and maintained have thus been shaped by the model organism under study and the type of methods used to study them. The current picture is one of a dynamic and adaptative process, based on a spatial segregation of components that network to achieve growth and respond to environmental (extracellular) cues. Here, we explore some examples of our live imaging research, namely on cyclic nucleotide gated ion channels, lipid kinases and syntaxins involved in exocytosis. We discuss how their spatial distribution, activity and concentration suggest that the players regulating apical cell growth may display more mobility than previously thought. Furthermore, we speculate on the implications of such perspective in our understanding of the mechanisms regulating apical cell growth and their responses to extracellular cues.
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Affiliation(s)
- Rui Malhó
- *Correspondence: Rui Malhó and Reiaz Ul-Rehman, BioISI – Biosystems & Integrative Sciences Institute, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal, ,
| | | | - Laura Saavedra
- †Present address: Laura Saavedra, Cátedra de Fisiología Vegetal, Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de Córdoba, Córdoba, Argentina; Reiaz Ul-Rehman, Department of Bioresources, University of Kashmir, Hazratbal, Srinagar 190006, India
| | | | - Reiaz Ul-Rehman
- *Correspondence: Rui Malhó and Reiaz Ul-Rehman, BioISI – Biosystems & Integrative Sciences Institute, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal, ,
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