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Zuriegat Q, Abubakar YS, Wang Z, Chen M, Zhang J. Emerging Roles of Exocyst Complex in Fungi: A Review. J Fungi (Basel) 2024; 10:614. [PMID: 39330374 PMCID: PMC11433146 DOI: 10.3390/jof10090614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2024] [Revised: 08/19/2024] [Accepted: 08/21/2024] [Indexed: 09/28/2024] Open
Abstract
The exocyst complex, an evolutionarily conserved octameric protein assembly, plays a central role in the targeted binding and fusion of vesicles at the plasma membrane. In fungal cells, this transport system is essential for polarized growth, morphogenesis, cell wall maintenance and virulence. Recent advances have greatly improved our understanding of the role and regulation of the exocyst complex in fungi. This review synthesizes these developments and focuses on the intricate interplay between the exocyst complex, specific fungal cargos and regulatory proteins. Insights into thestructure of the exocyst and its functional dynamics have revealed new dimensions of its architecture and its interactions with the cellular environment. Furthermore, the regulation of exocyst activity involves complex signaling pathways and interactions with cytoskeletal elements that are crucial for its role in vesicle trafficking. By exploring these emerging themes, this review provides a comprehensive overview of the multifaceted functions of the exocyst complex in fungal biology. Understanding these mechanisms offers potential avenues for novel therapeutic strategies against fungal pathogens and insights into the general principles of vesicle trafficking in eukaryotic cells. The review therefore highlights the importance of the exocyst complex in maintaining cellular functions and its broader implications in fungal pathogenicity and cell biology.
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Affiliation(s)
- Qussai Zuriegat
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Ministerial and Provincial Joint Innovation Centre for Safety Production of Cross-Strait Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (Q.Z.); (Y.S.A.); (Z.W.)
| | - Yakubu Saddeeq Abubakar
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Ministerial and Provincial Joint Innovation Centre for Safety Production of Cross-Strait Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (Q.Z.); (Y.S.A.); (Z.W.)
| | - Zonghua Wang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Ministerial and Provincial Joint Innovation Centre for Safety Production of Cross-Strait Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (Q.Z.); (Y.S.A.); (Z.W.)
- Fujian Key Laboratory on Conservation and Sustainable Utilization of Marine Biodiversity, College of Materials and Chemical Engineering, Minjiang University, Fuzhou 350108, China
| | - Meilian Chen
- Fujian Key Laboratory on Conservation and Sustainable Utilization of Marine Biodiversity, College of Materials and Chemical Engineering, Minjiang University, Fuzhou 350108, China
| | - Jun Zhang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Ministerial and Provincial Joint Innovation Centre for Safety Production of Cross-Strait Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China; (Q.Z.); (Y.S.A.); (Z.W.)
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Wang Y, Xiao T, Zhao C, Li G. The Regulation of Exosome Generation and Function in Physiological and Pathological Processes. Int J Mol Sci 2023; 25:255. [PMID: 38203424 PMCID: PMC10779122 DOI: 10.3390/ijms25010255] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 12/16/2023] [Accepted: 12/21/2023] [Indexed: 01/12/2024] Open
Abstract
Exosomes, a type of extracellular vesicle with a diameter of approximately 100 nm that is secreted by all cells, regulate the phenotype and function of recipient cells by carrying molecules such as proteins, nucleic acids, and lipids and are important mediators of intercellular communication. Exosomes are involved in various physiological and pathological processes such as immunomodulation, angiogenesis, tumorigenesis, metastasis, and chemoresistance. Due to their excellent properties, exosomes have shown their potential application in the clinical diagnosis and treatment of disease. The functions of exosomes depend on their biogenesis, uptake, and composition. Thus, a deeper understanding of these processes and regulatory mechanisms can help to find new targets for disease diagnosis and therapy. Therefore, this review summarizes and integrates the recent advances in the regulatory mechanisms of the entire biological process of exosomes, starting from the formation of early-sorting endosomes (ESCs) by plasma membrane invagination to the release of exosomes by fusion of multivesicular bodies (MVBs) with the plasma membrane, as well as the regulatory process of the interactions between exosomes and recipient cells. We also describe and discuss the regulatory mechanisms of exosome production in tumor cells and the potential of exosomes used in cancer diagnosis and therapy.
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Affiliation(s)
| | | | | | - Guiying Li
- Key Laboratory for Molecular Enzymology and Engineering of the Ministry of Education, School of Life Sciences, Jilin University, Changchun 130012, China; (Y.W.); (T.X.); (C.Z.)
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3
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Liu L, Gu C, Zhang J, Guo J, Zhang X, Zhou Z. Genome-Wide Analysis of Exocyst Complex Subunit Exo70 Gene Family in Cucumber. Int J Mol Sci 2023; 24:10929. [PMID: 37446106 DOI: 10.3390/ijms241310929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 06/25/2023] [Accepted: 06/27/2023] [Indexed: 07/15/2023] Open
Abstract
Cucumber (Cucumis sativus L.) is an important vegetable worldwide, but its yield is affected by a wide range of pathogens and pests. As the major subunit of the exocyst complex, the roles of Exo70 members have been shown in Arabidopsis and rice, but their function are unknown in cucumber. Here, we identified 18 CsExo70 members in cucumber, which were divided into three groups (Exo70.1-Exo70.3) and nine subgroups (Exo70A-Exo70I) based on the phylogenetic tree. Subsequently, systematical analyses were performed, including collinearity, gene structure, cis-acting elements, conserved motifs, expression patterns, and subcellular localization. Our results showed that CsExo70 genes were generally expressed in all tissues, and CsExo70C1 and CsExo70C2 were highly expressed in the stamen. Moreover, the expression levels of most CsExo70 genes were induced by Pseudomonas syringae pv. lachrymans (Psl) and Fusarium oxysporum f. sp. cucumerinum Owen (Foc), especially CsExo70E2 and CsExo70H3. In addition, these CsExo70s displayed similar location patterns with discrete and punctate signals in the cytoplasm. Together, our results indicate that CsExo70 members may be involved in plant development and resistance, and provide a reference for future in-depth studies of Exo70 genes in cucumber.
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Affiliation(s)
- Liu Liu
- Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, Department of Vegetable Sciences, China Agricultural University, Beijing 100193, China
| | - Chaoheng Gu
- Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, Department of Vegetable Sciences, China Agricultural University, Beijing 100193, China
| | - Jiahao Zhang
- Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, Department of Vegetable Sciences, China Agricultural University, Beijing 100193, China
| | - Jingyu Guo
- Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, Department of Vegetable Sciences, China Agricultural University, Beijing 100193, China
| | - Xiaolan Zhang
- Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, Department of Vegetable Sciences, China Agricultural University, Beijing 100193, China
| | - Zhaoyang Zhou
- Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, Department of Vegetable Sciences, China Agricultural University, Beijing 100193, China
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Peer M, Yuan H, Zhang Y, Korbula K, Novick P, Dong G. Double NPY motifs at the N-terminus of the yeast t-SNARE Sso2 synergistically bind Sec3 to promote membrane fusion. eLife 2022; 11:82041. [PMID: 35979953 PMCID: PMC9427108 DOI: 10.7554/elife.82041] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Accepted: 07/29/2022] [Indexed: 11/29/2022] Open
Abstract
Exocytosis is an active vesicle trafficking process by which eukaryotes secrete materials to the extracellular environment and insert membrane proteins into the plasma membrane. The final step of exocytosis in yeast involves the assembly of two t-SNAREs, Sso1/2 and Sec9, with the v-SNARE, Snc1/2, on secretory vesicles. The rate-limiting step in this process is the formation of a binary complex of the two t-SNAREs. Despite a previous report of acceleration of binary complex assembly by Sec3, it remains unknown how Sso2 is efficiently recruited to the vesicle-docking site marked by Sec3. Here, we report a crystal structure of the pleckstrin homology (PH) domain of Sec3 in complex with a nearly full-length version of Sso2 lacking only its C-terminal transmembrane helix. The structure shows a previously uncharacterized binding site for Sec3 at the N-terminus of Sso2, consisting of two highly conserved triple residue motifs (NPY: Asn-Pro-Tyr). We further reveal that the two NPY motifs bind Sec3 synergistically, which together with the previously reported binding interface constitute dual-site interactions between Sso2 and Sec3 to drive the fusion of secretory vesicles at target sites on the plasma membrane.
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Affiliation(s)
- Maximilian Peer
- Vienna Biocenter, Medical University of Vienna, Vienna, Austria
| | - Hua Yuan
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, United States
| | - Yubo Zhang
- Vienna Biocenter, Medical University of Vienna, Vienna, Austria
| | | | - Peter Novick
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, United States
| | - Gang Dong
- Medical Unviersity of Vienna, Vienna, Austria
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Fadil SA, Janetopoulos C. The Polarized Redistribution of the Contractile Vacuole to the Rear of the Cell is Critical for Streaming and is Regulated by PI(4,5)P2-Mediated Exocytosis. Front Cell Dev Biol 2022; 9:765316. [PMID: 35928786 PMCID: PMC9344532 DOI: 10.3389/fcell.2021.765316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Accepted: 10/20/2021] [Indexed: 12/05/2022] Open
Abstract
Dictyostelium discoideum amoebae align in a head to tail manner during the process of streaming during fruiting body formation. The chemoattractant cAMP is the chemoattractant regulating cell migration during this process and is released from the rear of cells. The process by which this cAMP release occurs has eluded investigators for many decades, but new findings suggest that this release can occur through expulsion during contractile vacuole (CV) ejection. The CV is an organelle that performs several functions inside the cell including the regulation of osmolarity, and discharges its content via exocytosis. The CV localizes to the rear of the cell and appears to be part of the polarity network, with the localization under the influence of the plasma membrane (PM) lipids, including the phosphoinositides (PIs), among those is PI(4,5)P2, the most abundant PI on the PM. Research on D. discoideum and neutrophils have shown that PI(4,5)P2 is enriched at the rear of migrating cells. In several systems, it has been shown that the essential regulator of exocytosis is through the exocyst complex, mediated in part by PI(4,5)P2-binding. This review features the role of the CV complex in D. discoideum signaling with a focus on the role of PI(4,5)P2 in regulating CV exocytosis and localization. Many of the regulators of these processes are conserved during evolution, so the mechanisms controlling exocytosis and membrane trafficking in D. discoideum and mammalian cells will be discussed, highlighting their important functions in membrane trafficking and signaling in health and disease.
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Affiliation(s)
- Sana A. Fadil
- Department of Biological Sciences, University of the Sciences in Philadelphia, Philadelphia, PA, United States
- Department of Natural product, Faculty of Pharmacy, King Abdulaziz University, Saudia Arabia
| | - Chris Janetopoulos
- Department of Biological Sciences, University of the Sciences in Philadelphia, Philadelphia, PA, United States
- The Science Research Institute, Albright College, Reading, PA, United States
- The Department of Cell Biology at Johns Hopkins University School of Medicine, Baltimore, MD, United States
- *Correspondence: Chris Janetopoulos,
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6
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Žárský V. Exocyst functions in plants - secretion and autophagy. FEBS Lett 2022; 596:2324-2334. [PMID: 35729750 DOI: 10.1002/1873-3468.14430] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Revised: 06/03/2022] [Accepted: 06/03/2022] [Indexed: 11/09/2022]
Abstract
Tethering complexes mediate vesicle-target compartment contact. Octameric complex exocyst initiates vesicle exocytosis at specific cytoplasmic membrane domains. Plant exocyst is possibly stabilized at the membrane by a direct interaction between SEC3 and EXO70A. Land plants evolved three basic membrane-targeting EXO70 subfamilies, the evolution of which resulted in several types of exocyst with distinct functions within the same cell. Surprisingly, some of these EXO70-exocyst versions are implicated in autophagy as is animal exocyst or are involved in host defense, cell-wall fortification and secondary metabolites transport. Interestingly, EXO70Ds act as selective autophagy receptors in the regulation of cytokinin signalling pathway. Secretion of double membrane autophagy-related structures formed with the contribution of EXO70s to the apoplast hints at the possibility of secretory autophagy in plants.
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Affiliation(s)
- Viktor Žárský
- Department of Experimental Plant Biology, Faculty of Science, Charles University in Prague, Viničná 5, 128 44, Prague, Czech Republic.,Institute of Experimental Botany, v.v.i., Czech Academy of Sciences, Rozvojová 263, 165 02, Prague, Czech Republic
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7
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Çetinbaş-Genç A, Conti V, Cai G. Let's shape again: the concerted molecular action that builds the pollen tube. PLANT REPRODUCTION 2022; 35:77-103. [PMID: 35041045 DOI: 10.1007/s00497-022-00437-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 01/06/2022] [Indexed: 06/14/2023]
Abstract
The pollen tube is being subjected to control by a complex network of communication that regulates its shape and the misfunction of a single component causes specific deformations. In flowering plants, the pollen tube is a tubular extension of the pollen grain required for successful sexual reproduction. Indeed, maintaining the unique shape of the pollen tube is essential for the pollen tube to approach the embryo sac. Many processes and molecules (such as GTPase activity, phosphoinositides, Ca2+ gradient, distribution of reactive oxygen species and nitric oxide, nonuniform pH values, organization of the cytoskeleton, balance between exocytosis and endocytosis, and cell wall structure) play key and coordinated roles in maintaining the cylindrical shape of pollen tubes. In addition, the above factors must also interact with each other so that the cell shape is maintained while the pollen tube follows chemical signals in the pistil that guide it to the embryo sac. Any intrinsic changes (such as erroneous signals) or extrinsic changes (such as environmental stresses) can affect the above factors and thus fertilization by altering the tube morphology. In this review, the processes and molecules that enable the development and maintenance of the unique shape of pollen tubes in angiosperms are presented emphasizing their interaction with specific tube shape. Thus, the purpose of the review is to investigate whether specific deformations in pollen tubes can help us to better understand the mechanism underlying pollen tube shape.
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Affiliation(s)
- Aslıhan Çetinbaş-Genç
- Department of Biology, Marmara University, Göztepe Campus, 34722, Kadıköy, Istanbul, Turkey.
| | - Veronica Conti
- Department of Life Sciences, University of Siena, via Mattioli 4, 53100, Siena, Italy
| | - Giampiero Cai
- Department of Life Sciences, University of Siena, via Mattioli 4, 53100, Siena, Italy
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8
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Laquel P, Testet E, Tuphile K, Cullin C, Fouillen L, Bessoule JJ, Doignon F. Phosphoinositides containing stearic acid are required for interaction between Rho GTPases and the exocyst to control the late steps of polarised exocytosis. Traffic 2021; 23:120-136. [PMID: 34908215 DOI: 10.1111/tra.12829] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 11/18/2021] [Accepted: 12/07/2021] [Indexed: 11/27/2022]
Abstract
Cell polarity is achieved by regulators such as small G proteins, exocyst members and phosphoinositides, with the latter playing a key role when bound to the exocyst proteins Sec3p and Exo70p, and Rho GTPases. This ensures asymmetric growth via the routing of proteins and lipids to the cell surface using actin cables. Previously, using a yeast mutant for a lysophosphatidylinositol acyl transferase encoded by the PSI1 gene, we demonstrated the role of stearic acid in the acyl chain of phosphoinositides in cytoskeletal organisation and secretion. Here, we use a genetic approach to characterise the effect on late steps of the secretory pathway. The constitutive overexpression of PSI1 in mutants affecting kinases involved in the phosphoinositide pathway demonstrated the role of molecular species containing stearic acid in bypassing a lack of phosphatidylinositol-4-phosphate PI(4)P at the plasma membrane, which is essential for the function of the Cdc42p module. Decreasing the levels of stearic acid-containing phosphoinositides modifies the environment of the actors involved in the control of late steps in the secretory pathway. This leads to decreased interactions between Exo70p and Sec3p, with Cdc42p, Rho1p and Rho3p, due to disruption of the GTP/GDP ratio of at least Rho1p and Rho3p GTPases, thereby preventing activation of the exocyst.
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Affiliation(s)
- P Laquel
- Univ. Bordeaux, CNRS, Laboratoire de Biogenèse Membranaire, UMR 5200, F-33140 Villenave d'Ornon, France
| | - E Testet
- Univ. Bordeaux, CNRS, Laboratoire de Biogenèse Membranaire, UMR 5200, F-33140 Villenave d'Ornon, France
| | - K Tuphile
- Univ. Bordeaux, CNRS, Laboratoire de Biogenèse Membranaire, UMR 5200, F-33140 Villenave d'Ornon, France
| | - C Cullin
- Univ. Bordeaux, CNRS, Laboratoire de Chimie Biologie des Membranes & des Nano-objets, UMR 5248, Pessac, France
| | - L Fouillen
- Univ. Bordeaux, CNRS, Laboratoire de Biogenèse Membranaire, UMR 5200, F-33140 Villenave d'Ornon, France.,Metabolome Facility of Bordeaux, Functional Genomics Centre, F-33883 Villenave d'Ornon, France
| | - J J Bessoule
- Univ. Bordeaux, CNRS, Laboratoire de Biogenèse Membranaire, UMR 5200, F-33140 Villenave d'Ornon, France
| | - F Doignon
- Univ. Bordeaux, CNRS, Laboratoire de Biogenèse Membranaire, UMR 5200, F-33140 Villenave d'Ornon, France
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9
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Bustos Plonka F, Sosa LJ, Quiroga S. Sec3 exocyst component knockdown inhibits axonal formation and cortical neuronal migration during brain cortex development. J Neurochem 2021; 160:203-217. [PMID: 34862972 DOI: 10.1111/jnc.15554] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 10/27/2021] [Accepted: 11/25/2021] [Indexed: 12/22/2022]
Abstract
Neurons are the largest known cells, with complex and highly polarized morphologies and consist of a cell body (soma), several dendrites, and a single axon. The establishment of polarity necessitates initial axonal outgrowth in concomitance with the addition of new membrane to the axon's plasmalemma. Axolemmal expansion occurs by exocytosis of plasmalemmal precursor vesicles primarily at the neuronal growth cone membrane. The multiprotein exocyst complex drives spatial location and specificity of vesicle fusion at plasma membrane. However, the specific participation of its different proteins on neuronal differentiation has not been fully established. In the present work we analyzed the role of Sec3, a prominent exocyst complex protein on neuronal differentiation. Using mice hippocampal primary cultures, we determined that Sec3 is expressed in neurons at early stages prior to neuronal polarization. Furthermore, we determined that silencing of Sec3 in mice hippocampal neurons in culture precluded polarization. Moreover, using in utero electroporation experiments, we determined that Sec3 knockdown affected cortical neurons migration and morphology during neocortex formation. Our results demonstrate that the exocyst complex protein Sec3 plays an important role in axon formation in neuronal differentiation and the migration of neuronal progenitors during cortex development.
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Affiliation(s)
- Florentyna Bustos Plonka
- Facultad de Ciencias Químicas, Departamento de Química Biológica Ranwel Caputto, Universidad Nacional de Córdoba y CIQUIBIC-CONICET, Córdoba, Argentina
| | - Lucas J Sosa
- Facultad de Ciencias Químicas, Departamento de Química Biológica Ranwel Caputto, Universidad Nacional de Córdoba y CIQUIBIC-CONICET, Córdoba, Argentina
| | - Santiago Quiroga
- Facultad de Ciencias Químicas, Departamento de Química Biológica Ranwel Caputto, Universidad Nacional de Córdoba y CIQUIBIC-CONICET, Córdoba, Argentina
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Chan EHY, Zhou Y, Aerne BL, Holder MV, Weston A, Barry DJ, Collinson L, Tapon N. RASSF8-mediated transport of Echinoid via the exocyst promotes Drosophila wing elongation and epithelial ordering. Development 2021; 148:dev199731. [PMID: 34532737 PMCID: PMC8572004 DOI: 10.1242/dev.199731] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 09/13/2021] [Indexed: 01/14/2023]
Abstract
Cell-cell junctions are dynamic structures that maintain cell cohesion and shape in epithelial tissues. During development, junctions undergo extensive rearrangements to drive the epithelial remodelling required for morphogenesis. This is particularly evident during axis elongation, where neighbour exchanges, cell-cell rearrangements and oriented cell divisions lead to large-scale alterations in tissue shape. Polarised vesicle trafficking of junctional components by the exocyst complex has been proposed to promote junctional rearrangements during epithelial remodelling, but the receptors that allow exocyst docking to the target membranes remain poorly understood. Here, we show that the adherens junction component Ras Association domain family 8 (RASSF8) is required for the epithelial re-ordering that occurs during Drosophila pupal wing proximo-distal elongation. We identify the exocyst component Sec15 as a RASSF8 interactor. Loss of RASSF8 elicits cytoplasmic accumulation of Sec15 and Rab11-containing vesicles. These vesicles also contain the nectin-like homophilic adhesion molecule Echinoid, the depletion of which phenocopies the wing elongation and epithelial packing defects observed in RASSF8 mutants. Thus, our results suggest that RASSF8 promotes exocyst-dependent docking of Echinoid-containing vesicles during morphogenesis.
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Affiliation(s)
- Eunice H. Y. Chan
- Apoptosis and Proliferation Control Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Yanxiang Zhou
- Apoptosis and Proliferation Control Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Birgit L. Aerne
- Apoptosis and Proliferation Control Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Maxine V. Holder
- Apoptosis and Proliferation Control Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Anne Weston
- Electron Microscopy Science Technology Platform, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - David J. Barry
- Advanced Light Microscopy Science Technology Platform, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Lucy Collinson
- Electron Microscopy Science Technology Platform, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Nicolas Tapon
- Apoptosis and Proliferation Control Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
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11
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Plasma membrane phospholipid signature recruits the plant exocyst complex via the EXO70A1 subunit. Proc Natl Acad Sci U S A 2021; 118:2105287118. [PMID: 34470819 DOI: 10.1073/pnas.2105287118] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Polarized exocytosis is essential for many vital processes in eukaryotic cells, where secretory vesicles are targeted to distinct plasma membrane domains characterized by their specific lipid-protein composition. Heterooctameric protein complex exocyst facilitates the vesicle tethering to a target membrane and is a principal cell polarity regulator in eukaryotes. The architecture and molecular details of plant exocyst and its membrane recruitment have remained elusive. Here, we show that the plant exocyst consists of two modules formed by SEC3-SEC5-SEC6-SEC8 and SEC10-SEC15-EXO70-EXO84 subunits, respectively, documenting the evolutionarily conserved architecture within eukaryotes. In contrast to yeast and mammals, the two modules are linked by a plant-specific SEC3-EXO70 interaction, and plant EXO70 functionally dominates over SEC3 in the exocyst recruitment to the plasma membrane. Using an interdisciplinary approach, we found that the C-terminal part of EXO70A1, the canonical EXO70 isoform in Arabidopsis, is critical for this process. In contrast to yeast and animal cells, the EXO70A1 interaction with the plasma membrane is mediated by multiple anionic phospholipids uniquely contributing to the plant plasma membrane identity. We identified several evolutionary conserved EXO70 lysine residues and experimentally proved their importance for the EXO70A1-phospholipid interactions. Collectively, our work has uncovered plant-specific features of the exocyst complex and emphasized the importance of the specific protein-lipid code for the recruitment of peripheral membrane proteins.
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12
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Zhang W, Huang L, Zhang C, Staiger CJ. Arabidopsis myosin XIK interacts with the exocyst complex to facilitate vesicle tethering during exocytosis. THE PLANT CELL 2021; 33:2454-2478. [PMID: 33871640 PMCID: PMC8364239 DOI: 10.1093/plcell/koab116] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 04/13/2021] [Indexed: 05/17/2023]
Abstract
Myosin motors are essential players in secretory vesicle trafficking and exocytosis in yeast and mammalian cells; however, similar roles in plants remain a matter for debate, at least for diffusely growing cells. Here, we demonstrate that Arabidopsis (Arabidopsis thaliana) myosin XIK, via its globular tail domain (GTD), participates in the vesicle tethering step of exocytosis through direct interactions with the exocyst complex. Specifically, myosin XIK GTD bound directly to several exocyst subunits in vitro and functional fluorescently tagged XIK colocalized with multiple exocyst subunits at plasma membrane (PM)-associated stationary foci. Moreover, genetic and pharmacological inhibition of myosin XI activity reduced the rate of appearance and lifetime of stationary exocyst complexes at the PM. By tracking single exocytosis events of cellulose synthase (CESA) complexes with high spatiotemporal resolution imaging and pair-wise colocalization of myosin XIK, exocyst subunits, and CESA6, we demonstrated that XIK associates with secretory vesicles earlier than exocyst and is required for the efficient localization and normal dynamic behavior of exocyst complex at the PM tethering site. This study reveals an important functional role for myosin XI in secretion and provides insights about the dynamic regulation of exocytosis in plants.
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Affiliation(s)
- Weiwei Zhang
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907, USA
| | - Lei Huang
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907, USA
| | - Chunhua Zhang
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907, USA
- Center for Plant Biology, College of Agriculture, Purdue University, West Lafayette, Indiana 47907, USA
| | - Christopher J. Staiger
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907, USA
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907, USA
- Center for Plant Biology, College of Agriculture, Purdue University, West Lafayette, Indiana 47907, USA
- Author for correspondence:
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Brillada C, Teh OK, Ditengou FA, Lee CW, Klecker T, Saeed B, Furlan G, Zietz M, Hause G, Eschen-Lippold L, Hoehenwarter W, Lee J, Ott T, Trujillo M. Exocyst subunit Exo70B2 is linked to immune signaling and autophagy. THE PLANT CELL 2021; 33:404-419. [PMID: 33630076 PMCID: PMC8136888 DOI: 10.1093/plcell/koaa022] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 11/18/2020] [Indexed: 05/08/2023]
Abstract
During the immune response, activation of the secretory pathway is key to mounting an effective response, while gauging its output is important to maintain cellular homeostasis. The Exo70 subunit of the exocyst functions as a spatiotemporal regulator by mediating numerous interactions with proteins and lipids. However, a molecular understanding of the exocyst regulation remains challenging. We show that, in Arabidopsis thaliana, Exo70B2 behaves as a bona fide exocyst subunit. Conversely, treatment with the salicylic acid (SA) defence hormone analog benzothiadiazole (BTH), or the immunogenic peptide flg22, induced Exo70B2 transport into the vacuole. We reveal that Exo70B2 interacts with AUTOPHAGY-RELATED PROTEIN 8 (ATG8) via two ATG8-interacting motives (AIMs) and its transport into the vacuole is dependent on autophagy. In line with its role in immunity, we discovered that Exo70B2 interacted with and was phosphorylated by the kinase MPK3. Mimicking phosphorylation had a dual impact on Exo70B2: first, by inhibiting localization at sites of active secretion, and second, it increased the interaction with ATG8. Phosphonull variants displayed higher effector-triggered immunity (ETI) and were hypersensitive to BTH, which induce secretion and autophagy. Our results suggest a molecular mechanism by which phosphorylation diverts Exo70B2 from the secretory into the autophagy pathway for its degradation, to dampen secretory activity.
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Affiliation(s)
- Carla Brillada
- Faculty of Biology, Cell Biology, University of Freiburg, 79104 Freiburg, Germany
| | - Ooi-Kock Teh
- Leibniz Institute of Plant Biochemistry, 06120 Halle (Saale), Germany
- Department of Biological Science, School of Science, Hokkaido University, 060-0810 Sapporo, Japan
- Institute for the Advancement of Higher Education, Hokkaido University, 060-0815 Sapporo, Japan
| | | | - Chil-Woo Lee
- Leibniz Institute of Plant Biochemistry, 06120 Halle (Saale), Germany
| | - Till Klecker
- Institute of Cell Biology, University of Bayreuth, 95440 Bayreuth, Germany
| | - Bushra Saeed
- Faculty of Biology, Cell Biology, University of Freiburg, 79104 Freiburg, Germany
| | - Giulia Furlan
- Leibniz Institute of Plant Biochemistry, 06120 Halle (Saale), Germany
| | - Marco Zietz
- Leibniz Institute of Plant Biochemistry, 06120 Halle (Saale), Germany
| | - Gerd Hause
- Biozentrum, Martin-Luther-University Halle-Wittenberg, Halle 06120 (Saale), Germany
| | | | | | - Justin Lee
- Leibniz Institute of Plant Biochemistry, 06120 Halle (Saale), Germany
| | - Thomas Ott
- Faculty of Biology, Cell Biology, University of Freiburg, 79104 Freiburg, Germany
- CIBSS—Centre for Integrative Biological Signalling Studies, University of Freiburg, 79085 Freiburg, Germany
| | - Marco Trujillo
- Faculty of Biology, Cell Biology, University of Freiburg, 79104 Freiburg, Germany
- Leibniz Institute of Plant Biochemistry, 06120 Halle (Saale), Germany
- Author for communication:
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14
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Ruan H, Li J, Wang T, Ren H. Secretory Vesicles Targeted to Plasma Membrane During Pollen Germination and Tube Growth. Front Cell Dev Biol 2021; 8:615447. [PMID: 33553150 PMCID: PMC7859277 DOI: 10.3389/fcell.2020.615447] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 12/14/2020] [Indexed: 12/12/2022] Open
Abstract
Pollen germination and pollen tube growth are important biological events in the sexual reproduction of higher plants, during which a large number of vesicle trafficking and membrane fusion events occur. When secretory vesicles are transported via the F-actin network in proximity to the apex of the pollen tube, the secretory vesicles are tethered and fused to the plasma membrane by tethering factors and SNARE proteins, respectively. The coupling and uncoupling between the vesicle membrane and plasma membrane are also regulated by dynamic cytoskeleton, proteins, and signaling molecules, including small G proteins, calcium, and PIP2. In this review, we focus on the current knowledge regarding secretory vesicle delivery, tethering, and fusion during pollen germination and tube growth and summarize the progress in research on how regulators and signaling molecules participate in the above processes.
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Affiliation(s)
- Huaqiang Ruan
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, Center for Biological Science and Technology, Advanced Institute of Natural Science, Beijing Normal University, Zhuhai, China
| | - Jiang Li
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, Center for Biological Science and Technology, Advanced Institute of Natural Science, Beijing Normal University, Zhuhai, China
| | - Ting Wang
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, Center for Biological Science and Technology, Advanced Institute of Natural Science, Beijing Normal University, Zhuhai, China
| | - Haiyun Ren
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, Center for Biological Science and Technology, Advanced Institute of Natural Science, Beijing Normal University, Zhuhai, China
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15
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Fais M, Sanna G, Galioto M, Nguyen TTD, Trần MUT, Sini P, Carta F, Turrini F, Xiong Y, Dawson TM, Dawson VL, Crosio C, Iaccarino C. LRRK2 Modulates the Exocyst Complex Assembly by Interacting with Sec8. Cells 2021; 10:203. [PMID: 33498474 PMCID: PMC7909581 DOI: 10.3390/cells10020203] [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: 10/28/2020] [Revised: 01/12/2021] [Accepted: 01/18/2021] [Indexed: 11/17/2022] Open
Abstract
Mutations in LRRK2 play a critical role in both familial and sporadic Parkinson's disease (PD). Up to date, the role of LRRK2 in PD onset and progression remains largely unknown. However, experimental evidence highlights a critical role of LRRK2 in the control of vesicle trafficking, likely by Rab phosphorylation, that in turn may regulate different aspects of neuronal physiology. Here we show that LRRK2 interacts with Sec8, one of eight subunits of the exocyst complex. The exocyst complex is an evolutionarily conserved multisubunit protein complex mainly involved in tethering secretory vesicles to the plasma membrane and implicated in the regulation of multiple biological processes modulated by vesicle trafficking. Interestingly, Rabs and exocyst complex belong to the same protein network. Our experimental evidence indicates that LRRK2 kinase activity or the presence of the LRRK2 kinase domain regulate the assembly of exocyst subunits and that the over-expression of Sec8 significantly rescues the LRRK2 G2019S mutant pathological effect. Our findings strongly suggest an interesting molecular mechanism by which LRRK2 could modulate vesicle trafficking and may have important implications to decode the complex role that LRRK2 plays in neuronal physiology.
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Affiliation(s)
- Milena Fais
- Department of Biomedical Sciences, University of Sassari, 07100 Sassari, Italy; (M.F.); (G.S.); (M.G.); (T.T.D.N.); (M.U.T.T.); (P.S.); (C.C.)
| | - Giovanna Sanna
- Department of Biomedical Sciences, University of Sassari, 07100 Sassari, Italy; (M.F.); (G.S.); (M.G.); (T.T.D.N.); (M.U.T.T.); (P.S.); (C.C.)
| | - Manuela Galioto
- Department of Biomedical Sciences, University of Sassari, 07100 Sassari, Italy; (M.F.); (G.S.); (M.G.); (T.T.D.N.); (M.U.T.T.); (P.S.); (C.C.)
| | - Thi Thanh Duyen Nguyen
- Department of Biomedical Sciences, University of Sassari, 07100 Sassari, Italy; (M.F.); (G.S.); (M.G.); (T.T.D.N.); (M.U.T.T.); (P.S.); (C.C.)
| | - Mai Uyên Thi Trần
- Department of Biomedical Sciences, University of Sassari, 07100 Sassari, Italy; (M.F.); (G.S.); (M.G.); (T.T.D.N.); (M.U.T.T.); (P.S.); (C.C.)
| | - Paola Sini
- Department of Biomedical Sciences, University of Sassari, 07100 Sassari, Italy; (M.F.); (G.S.); (M.G.); (T.T.D.N.); (M.U.T.T.); (P.S.); (C.C.)
| | | | - Franco Turrini
- Nurex Srl, 07100 Sassari, Italy; (F.C.); (F.T.)
- Department of Oncology, University of Turin, 10126 Turin, Italy
| | - Yulan Xiong
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; (Y.X.); (T.M.D.); (V.L.D.)
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Ted M. Dawson
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; (Y.X.); (T.M.D.); (V.L.D.)
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Valina L. Dawson
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; (Y.X.); (T.M.D.); (V.L.D.)
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Claudia Crosio
- Department of Biomedical Sciences, University of Sassari, 07100 Sassari, Italy; (M.F.); (G.S.); (M.G.); (T.T.D.N.); (M.U.T.T.); (P.S.); (C.C.)
| | - Ciro Iaccarino
- Department of Biomedical Sciences, University of Sassari, 07100 Sassari, Italy; (M.F.); (G.S.); (M.G.); (T.T.D.N.); (M.U.T.T.); (P.S.); (C.C.)
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16
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Saccomanno A, Potocký M, Pejchar P, Hála M, Shikata H, Schwechheimer C, Žárský V. Regulation of Exocyst Function in Pollen Tube Growth by Phosphorylation of Exocyst Subunit EXO70C2. FRONTIERS IN PLANT SCIENCE 2021; 11:609600. [PMID: 33519861 PMCID: PMC7840542 DOI: 10.3389/fpls.2020.609600] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 12/22/2020] [Indexed: 06/12/2023]
Abstract
Exocyst is a heterooctameric protein complex crucial for the tethering of secretory vesicles to the plasma membrane during exocytosis. Compared to other eukaryotes, exocyst subunit EXO70 is represented by many isoforms in land plants whose cell biological and biological roles, as well as modes of regulation remain largely unknown. Here, we present data on the phospho-regulation of exocyst isoform EXO70C2, which we previously identified as a putative negative regulator of exocyst function in pollen tube growth. A comprehensive phosphoproteomic analysis revealed phosphorylation of EXO70C2 at multiple sites. We have now performed localization and functional studies of phospho-dead and phospho-mimetic variants of Arabidopsis EXO70C2 in transiently transformed tobacco pollen tubes and stably transformed Arabidopsis wild type and exo70C2 mutant plants. Our data reveal a dose-dependent effect of AtEXO70C2 overexpression on pollen tube growth rate and cellular architecture. We show that changes of the AtEXO70C2 phosphorylation status lead to distinct outcomes in wild type and exo70c2 mutant cells, suggesting a complex regulatory pattern. On the other side, phosphorylation does not affect the cytoplasmic localization of AtEXO70C2 or its interaction with putative secretion inhibitor ROH1 in the yeast two-hybrid system.
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Affiliation(s)
- Antonietta Saccomanno
- Laboratory of Cell Biology, Institute of Experimental Botany, Czech Academy of Sciences, Prague, Czechia
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czechia
| | - Martin Potocký
- Laboratory of Cell Biology, Institute of Experimental Botany, Czech Academy of Sciences, Prague, Czechia
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czechia
| | - Přemysl Pejchar
- Laboratory of Cell Biology, Institute of Experimental Botany, Czech Academy of Sciences, Prague, Czechia
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czechia
| | - Michal Hála
- Laboratory of Cell Biology, Institute of Experimental Botany, Czech Academy of Sciences, Prague, Czechia
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czechia
| | - Hiromasa Shikata
- Plant Systems Biology, Technische Universität München, Freising, Germany
| | | | - Viktor Žárský
- Laboratory of Cell Biology, Institute of Experimental Botany, Czech Academy of Sciences, Prague, Czechia
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czechia
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17
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D'Souza Z, Taher FS, Lupashin VV. Golgi inCOGnito: From vesicle tethering to human disease. Biochim Biophys Acta Gen Subj 2020; 1864:129694. [PMID: 32730773 PMCID: PMC7384418 DOI: 10.1016/j.bbagen.2020.129694] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 07/21/2020] [Accepted: 07/23/2020] [Indexed: 12/11/2022]
Abstract
The Conserved Oligomeric Golgi (COG) complex, a multi-subunit vesicle tethering complex of the CATCHR (Complexes Associated with Tethering Containing Helical Rods) family, controls several aspects of cellular homeostasis by orchestrating retrograde vesicle traffic within the Golgi. The COG complex interacts with all key players regulating intra-Golgi trafficking, namely SNAREs, SNARE-interacting proteins, Rabs, coiled-coil tethers, and vesicular coats. In cells, COG deficiencies result in the accumulation of non-tethered COG-complex dependent (CCD) vesicles, dramatic morphological and functional abnormalities of the Golgi and endosomes, severe defects in N- and O- glycosylation, Golgi retrograde trafficking, sorting and protein secretion. In humans, COG mutations lead to severe multi-systemic diseases known as COG-Congenital Disorders of Glycosylation (COG-CDG). In this report, we review the current knowledge of the COG complex and analyze COG-related trafficking and glycosylation defects in COG-CDG patients.
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Affiliation(s)
- Zinia D'Souza
- Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Farhana S Taher
- Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Vladimir V Lupashin
- Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, AR, USA.
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18
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Scholz P, Anstatt J, Krawczyk HE, Ischebeck T. Signalling Pinpointed to the Tip: The Complex Regulatory Network That Allows Pollen Tube Growth. PLANTS (BASEL, SWITZERLAND) 2020; 9:E1098. [PMID: 32859043 PMCID: PMC7569787 DOI: 10.3390/plants9091098] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 08/18/2020] [Accepted: 08/23/2020] [Indexed: 12/13/2022]
Abstract
Plants display a complex life cycle, alternating between haploid and diploid generations. During fertilisation, the haploid sperm cells are delivered to the female gametophyte by pollen tubes, specialised structures elongating by tip growth, which is based on an equilibrium between cell wall-reinforcing processes and turgor-driven expansion. One important factor of this equilibrium is the rate of pectin secretion mediated and regulated by factors including the exocyst complex and small G proteins. Critically important are also non-proteinaceous molecules comprising protons, calcium ions, reactive oxygen species (ROS), and signalling lipids. Among the latter, phosphatidylinositol 4,5-bisphosphate and the kinases involved in its formation have been assigned important functions. The negatively charged headgroup of this lipid serves as an interaction point at the apical plasma membrane for partners such as the exocyst complex, thereby polarising the cell and its secretion processes. Another important signalling lipid is phosphatidic acid (PA), that can either be formed by the combination of phospholipases C and diacylglycerol kinases or by phospholipases D. It further fine-tunes pollen tube growth, for example by regulating ROS formation. How the individual signalling cues are intertwined or how external guidance cues are integrated to facilitate directional growth remain open questions.
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Affiliation(s)
- Patricia Scholz
- Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences and Goettingen Center for Molecular Biosciences (GZMB), University of Goettingen, Justus-von-Liebig Weg 11, D-37077 Goettingen, Germany; (J.A.); (H.E.K.)
| | | | | | - Till Ischebeck
- Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences and Goettingen Center for Molecular Biosciences (GZMB), University of Goettingen, Justus-von-Liebig Weg 11, D-37077 Goettingen, Germany; (J.A.); (H.E.K.)
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19
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Pečenková T, Potocká A, Potocký M, Ortmannová J, Drs M, Janková Drdová E, Pejchar P, Synek L, Soukupová H, Žárský V, Cvrčková F. Redundant and Diversified Roles Among Selected Arabidopsis thaliana EXO70 Paralogs During Biotic Stress Responses. FRONTIERS IN PLANT SCIENCE 2020; 11:960. [PMID: 32676093 PMCID: PMC7333677 DOI: 10.3389/fpls.2020.00960] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Accepted: 06/11/2020] [Indexed: 05/28/2023]
Abstract
The heterooctameric vesicle-tethering complex exocyst is important for plant development, growth, and immunity. Multiple paralogs exist for most subunits of this complex; especially the membrane-interacting subunit EXO70 underwent extensive amplification in land plants, suggesting functional specialization. Despite this specialization, most Arabidopsis exo70 mutants are viable and free of developmental defects, probably as a consequence of redundancy among isoforms. Our in silico data-mining and modeling analysis, corroborated by transcriptomic experiments, pinpointed several EXO70 paralogs to be involved in plant biotic interactions. We therefore tested corresponding single and selected double mutant combinations (for paralogs EXO70A1, B1, B2, H1, E1, and F1) in their two biologically distinct responses to Pseudomonas syringae, root hair growth stimulation and general plant susceptibility. A shift in defense responses toward either increased or decreased sensitivity was found in several double mutants compared to wild type plants or corresponding single mutants, strongly indicating both additive and compensatory effects of exo70 mutations. In addition, our experiments confirm the lipid-binding capacity of selected EXO70s, however, without the clear relatedness to predicted C-terminal lipid-binding motifs. Our analysis uncovers that there is less of functional redundancy among isoforms than we could suppose from whole sequence phylogeny and that even paralogs with overlapping expression pattern and similar membrane-binding capacity appear to have exclusive roles in plant development and biotic interactions.
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Affiliation(s)
- Tamara Pečenková
- Institute of Experimental Botany, CAS, Prague, Czechia
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czechia
| | | | - Martin Potocký
- Institute of Experimental Botany, CAS, Prague, Czechia
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czechia
| | | | - Matěj Drs
- Institute of Experimental Botany, CAS, Prague, Czechia
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czechia
| | - Edita Janková Drdová
- Institute of Experimental Botany, CAS, Prague, Czechia
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czechia
| | - Přemysl Pejchar
- Institute of Experimental Botany, CAS, Prague, Czechia
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czechia
| | - Lukáš Synek
- Institute of Experimental Botany, CAS, Prague, Czechia
| | | | - Viktor Žárský
- Institute of Experimental Botany, CAS, Prague, Czechia
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czechia
| | - Fatima Cvrčková
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czechia
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20
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PI(4,5)P 2-dependent regulation of exocytosis by amisyn, the vertebrate-specific competitor of synaptobrevin 2. Proc Natl Acad Sci U S A 2020; 117:13468-13479. [PMID: 32467162 DOI: 10.1073/pnas.1908232117] [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] [Indexed: 12/26/2022] Open
Abstract
The functions of nervous and neuroendocrine systems rely on fast and tightly regulated release of neurotransmitters stored in secretory vesicles through SNARE-mediated exocytosis. Few proteins, including tomosyn (STXBP5) and amisyn (STXBP6), were proposed to negatively regulate exocytosis. Little is known about amisyn, a 24-kDa brain-enriched protein with a SNARE motif. We report here that full-length amisyn forms a stable SNARE complex with syntaxin-1 and SNAP-25 through its C-terminal SNARE motif and competes with synaptobrevin-2/VAMP2 for the SNARE-complex assembly. Furthermore, amisyn contains an N-terminal pleckstrin homology domain that mediates its transient association with the plasma membrane of neurosecretory cells by binding to phospholipid PI(4,5)P2 However, unlike synaptrobrevin-2, the SNARE motif of amisyn is not sufficient to account for the role of amisyn in exocytosis: Both the pleckstrin homology domain and the SNARE motif are needed for its inhibitory function. Mechanistically, amisyn interferes with the priming of secretory vesicles and the sizes of releasable vesicle pools, but not vesicle fusion properties. Our biochemical and functional analyses of this vertebrate-specific protein unveil key aspects of negative regulation of exocytosis.
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21
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Saeed B, Brillada C, Trujillo M. Dissecting the plant exocyst. CURRENT OPINION IN PLANT BIOLOGY 2019; 52:69-76. [PMID: 31509792 DOI: 10.1016/j.pbi.2019.08.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 07/12/2019] [Accepted: 08/08/2019] [Indexed: 06/10/2023]
Abstract
The exocyst is an evolutionary conserved complex that mediates tethering of post-Golgi vesicles derived from the conventional secretory pathway to the plasma membrane (PM), before SNARE-mediated fusion. Through its tethering function, connecting secretory vesicles to the PM, it mediates spatiotemporal regulation of exocytosis. As an integral element of the secretory machinery, the exocyst has been implicated in a large variety of processes. However, emerging evidence suggests that it may also cater for unconventional secretory pathways, as well as autophagy. The exocyst entertains a multitude of interactions with proteins and membrane phospholipids, reflecting its highly dynamic nature and the complex regulatory processes that hardwire it with cellular signalling networks. However, our molecular understanding of this essential complex remains fragmentary. Here we review recent work focusing on the molecular features that have revealed both commonalities with yeast and animals, as well as unique characteristics of the plant exocyst.
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Affiliation(s)
- Bushra Saeed
- Albert-Ludwigs-University Freiburg, Faculty of Biology, Institute of Biology II, 79104 Freiburg, Germany
| | - Carla Brillada
- Albert-Ludwigs-University Freiburg, Faculty of Biology, Institute of Biology II, 79104 Freiburg, Germany
| | - Marco Trujillo
- Albert-Ludwigs-University Freiburg, Faculty of Biology, Institute of Biology II, 79104 Freiburg, Germany.
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22
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Wang X, Tian W, Banh BT, Statler BM, Liang J, Stone DE. Mating yeast cells use an intrinsic polarity site to assemble a pheromone-gradient tracking machine. J Cell Biol 2019; 218:3730-3752. [PMID: 31570500 PMCID: PMC6829655 DOI: 10.1083/jcb.201901155] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 06/06/2019] [Accepted: 08/08/2019] [Indexed: 12/12/2022] Open
Abstract
The mating of budding yeast depends on chemotropism, a fundamental cellular process. The two yeast mating types secrete peptide pheromones that bind to GPCRs on cells of the opposite type. Cells find and contact a partner by determining the direction of the pheromone source and polarizing their growth toward it. Actin-directed secretion to the chemotropic growth site (CS) generates a mating projection. When pheromone-stimulated cells are unable to sense a gradient, they form mating projections where they would have budded in the next cell cycle, at a position called the default polarity site (DS). Numerous models have been proposed to explain yeast gradient sensing, but none address how cells reliably switch from the intrinsically determined DS to the gradient-aligned CS, despite a weak spatial signal. Here we demonstrate that, in mating cells, the initially uniform receptor and G protein first polarize to the DS, then redistribute along the plasma membrane until they reach the CS. Our data indicate that signaling, polarity, and trafficking proteins localize to the DS during assembly of what we call the gradient tracking machine (GTM). Differential activation of the receptor triggers feedback mechanisms that bias exocytosis upgradient and endocytosis downgradient, thus enabling redistribution of the GTM toward the pheromone source. The GTM stabilizes when the receptor peak centers at the CS and the endocytic machinery surrounds it. A computational model simulates GTM tracking and stabilization and correctly predicts that its assembly at a single site contributes to mating fidelity.
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Affiliation(s)
- Xin Wang
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL
| | - Wei Tian
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL
| | - Bryan T Banh
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL
| | | | - Jie Liang
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL
| | - David E Stone
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL
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23
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Enkavi G, Javanainen M, Kulig W, Róg T, Vattulainen I. Multiscale Simulations of Biological Membranes: The Challenge To Understand Biological Phenomena in a Living Substance. Chem Rev 2019; 119:5607-5774. [PMID: 30859819 PMCID: PMC6727218 DOI: 10.1021/acs.chemrev.8b00538] [Citation(s) in RCA: 184] [Impact Index Per Article: 36.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Indexed: 12/23/2022]
Abstract
Biological membranes are tricky to investigate. They are complex in terms of molecular composition and structure, functional over a wide range of time scales, and characterized by nonequilibrium conditions. Because of all of these features, simulations are a great technique to study biomembrane behavior. A significant part of the functional processes in biological membranes takes place at the molecular level; thus computer simulations are the method of choice to explore how their properties emerge from specific molecular features and how the interplay among the numerous molecules gives rise to function over spatial and time scales larger than the molecular ones. In this review, we focus on this broad theme. We discuss the current state-of-the-art of biomembrane simulations that, until now, have largely focused on a rather narrow picture of the complexity of the membranes. Given this, we also discuss the challenges that we should unravel in the foreseeable future. Numerous features such as the actin-cytoskeleton network, the glycocalyx network, and nonequilibrium transport under ATP-driven conditions have so far received very little attention; however, the potential of simulations to solve them would be exceptionally high. A major milestone for this research would be that one day we could say that computer simulations genuinely research biological membranes, not just lipid bilayers.
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Affiliation(s)
- Giray Enkavi
- Department
of Physics, University of
Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
| | - Matti Javanainen
- Department
of Physics, University of
Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
- Institute
of Organic Chemistry and Biochemistry of the Czech Academy
of Sciences, Flemingovo naḿesti 542/2, 16610 Prague, Czech Republic
- Computational
Physics Laboratory, Tampere University, P.O. Box 692, FI-33014 Tampere, Finland
| | - Waldemar Kulig
- Department
of Physics, University of
Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
| | - Tomasz Róg
- Department
of Physics, University of
Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
- Computational
Physics Laboratory, Tampere University, P.O. Box 692, FI-33014 Tampere, Finland
| | - Ilpo Vattulainen
- Department
of Physics, University of
Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
- Computational
Physics Laboratory, Tampere University, P.O. Box 692, FI-33014 Tampere, Finland
- MEMPHYS-Center
for Biomembrane Physics
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24
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Muller MP, Jiang T, Sun C, Lihan M, Pant S, Mahinthichaichan P, Trifan A, Tajkhorshid E. Characterization of Lipid-Protein Interactions and Lipid-Mediated Modulation of Membrane Protein Function through Molecular Simulation. Chem Rev 2019; 119:6086-6161. [PMID: 30978005 PMCID: PMC6506392 DOI: 10.1021/acs.chemrev.8b00608] [Citation(s) in RCA: 156] [Impact Index Per Article: 31.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The cellular membrane constitutes one of the most fundamental compartments of a living cell, where key processes such as selective transport of material and exchange of information between the cell and its environment are mediated by proteins that are closely associated with the membrane. The heterogeneity of lipid composition of biological membranes and the effect of lipid molecules on the structure, dynamics, and function of membrane proteins are now widely recognized. Characterization of these functionally important lipid-protein interactions with experimental techniques is however still prohibitively challenging. Molecular dynamics (MD) simulations offer a powerful complementary approach with sufficient temporal and spatial resolutions to gain atomic-level structural information and energetics on lipid-protein interactions. In this review, we aim to provide a broad survey of MD simulations focusing on exploring lipid-protein interactions and characterizing lipid-modulated protein structure and dynamics that have been successful in providing novel insight into the mechanism of membrane protein function.
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Affiliation(s)
- Melanie P. Muller
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology
- Department of Biochemistry
- Center for Biophysics and Quantitative Biology
- College of Medicine
- University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Tao Jiang
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology
- Department of Biochemistry
- Center for Biophysics and Quantitative Biology
- University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Chang Sun
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology
- Department of Biochemistry
- University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Muyun Lihan
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology
- Department of Biochemistry
- Center for Biophysics and Quantitative Biology
- University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Shashank Pant
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology
- Department of Biochemistry
- Center for Biophysics and Quantitative Biology
- University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Paween Mahinthichaichan
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology
- Department of Biochemistry
- University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Anda Trifan
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology
- Department of Biochemistry
- Center for Biophysics and Quantitative Biology
- University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Emad Tajkhorshid
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology
- Department of Biochemistry
- Center for Biophysics and Quantitative Biology
- College of Medicine
- University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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25
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Noack LC, Pejchar P, Sekereš J, Jaillais Y, Potocký M. Transient Gene Expression as a Tool to Monitor and Manipulate the Levels of Acidic Phospholipids in Plant Cells. Methods Mol Biol 2019; 1992:189-199. [PMID: 31148039 DOI: 10.1007/978-1-4939-9469-4_12] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Anionic phospholipids represent only minor fraction of cell membranes lipids but they are critically important for many membrane-related processes, including membrane identity, charge, shape, the generation of second messengers, and the recruitment of peripheral proteins. The main anionic phospholipids of the plasma membrane are phosphoinositides phosphatidylinositol 4-phosphate (PI4P), phosphatidylinositol 4,5-bisphosphate (PI4,5P2), phosphatidylserine (PS), and phosphatidic acid (PA). Recent insights in the understanding of the nature of protein-phospholipid interactions enabled the design of genetically encoded fluorescent molecular probes that can interact with various phospholipids in a specific manner allowing their imaging in live cells. Here, we describe the use of transiently transformed plant cells to study phospholipid-dependent membrane recruitment.
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Affiliation(s)
- Lise C Noack
- Laboratoire Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, CNRS, INRA, Lyon, France
| | - Přemysl Pejchar
- Institute of Experimental Botany, Czech Academy of Sciences, Prague, Czech Republic
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Juraj Sekereš
- Institute of Experimental Botany, Czech Academy of Sciences, Prague, Czech Republic
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Yvon Jaillais
- Laboratoire Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, CNRS, INRA, Lyon, France
| | - Martin Potocký
- Institute of Experimental Botany, Czech Academy of Sciences, Prague, Czech Republic.
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czech Republic.
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26
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Cole RA, Peremyslov VV, Van Why S, Moussaoui I, Ketter A, Cool R, Moreno MA, Vejlupkova Z, Dolja VV, Fowler JE. A broadly conserved NERD genetically interacts with the exocyst to affect root growth and cell expansion. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:3625-3637. [PMID: 29722827 PMCID: PMC6022600 DOI: 10.1093/jxb/ery162] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 04/24/2018] [Indexed: 05/10/2023]
Abstract
The exocyst, a conserved, octameric protein complex, helps mediate secretion at the plasma membrane, facilitating specific developmental processes that include control of root meristem size, cell elongation, and tip growth. A genetic screen for second-site enhancers in Arabidopsis identified NEW ENHANCER of ROOT DWARFISM1 (NERD1) as an exocyst interactor. Mutations in NERD1 combined with weak exocyst mutations in SEC8 and EXO70A1 result in a synergistic reduction in root growth. Alone, nerd1 alleles modestly reduce primary root growth, both by shortening the root meristem and by reducing cell elongation, but also result in a slight increase in root hair length, bulging, and rupture. NERD1 was identified molecularly as At3g51050, which encodes a transmembrane protein of unknown function that is broadly conserved throughout the Archaeplastida. A functional NERD1-GFP fusion localizes to the Golgi, in a pattern distinct from the plasma membrane-localized exocyst, arguing against a direct NERD1-exocyst interaction. Structural modeling suggests the majority of the protein is positioned in the lumen, in a β-propeller-like structure that has some similarity to proteins that bind polysaccharides. We suggest that NERD1 interacts with the exocyst indirectly, possibly affecting polysaccharides destined for the cell wall, and influencing cell wall characteristics in a developmentally distinct manner.
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Affiliation(s)
- Rex A Cole
- Department of Botany and Plant Pathology and Center for Genome Research and Biocomputing, Oregon State University, Corvallis, OR, USA
| | - Valera V Peremyslov
- Department of Botany and Plant Pathology and Center for Genome Research and Biocomputing, Oregon State University, Corvallis, OR, USA
| | - Savannah Van Why
- Department of Botany and Plant Pathology and Center for Genome Research and Biocomputing, Oregon State University, Corvallis, OR, USA
| | - Ibrahim Moussaoui
- Department of Botany and Plant Pathology and Center for Genome Research and Biocomputing, Oregon State University, Corvallis, OR, USA
| | - Ann Ketter
- Department of Botany and Plant Pathology and Center for Genome Research and Biocomputing, Oregon State University, Corvallis, OR, USA
| | - Renee Cool
- Department of Botany and Plant Pathology and Center for Genome Research and Biocomputing, Oregon State University, Corvallis, OR, USA
| | - Matthew Andres Moreno
- Department of Botany and Plant Pathology and Center for Genome Research and Biocomputing, Oregon State University, Corvallis, OR, USA
| | - Zuzana Vejlupkova
- Department of Botany and Plant Pathology and Center for Genome Research and Biocomputing, Oregon State University, Corvallis, OR, USA
| | - Valerian V Dolja
- Department of Botany and Plant Pathology and Center for Genome Research and Biocomputing, Oregon State University, Corvallis, OR, USA
| | - John E Fowler
- Department of Botany and Plant Pathology and Center for Genome Research and Biocomputing, Oregon State University, Corvallis, OR, USA
- Correspondence:
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27
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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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28
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Pecenková T, Markovic V, Sabol P, Kulich I, Žárský V. Exocyst and autophagy-related membrane trafficking in plants. JOURNAL OF EXPERIMENTAL BOTANY 2017; 69:47-57. [PMID: 29069430 DOI: 10.1093/jxb/erx363] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Endomembrane traffic in eukaryotic cells functions partially as a means of communication; delivery of membrane in one direction has to be balanced with a reduction at the other end. This effect is typically the case during the defence against pathogens. To combat pathogens, cellular growth and differentiation are suppressed, while endomembrane traffic is poised towards limiting the pathogen attack. The octameric exocyst vesicle-tethering complex was originally discovered as a factor facilitating vesicle-targeting and vesicle-plasma membrane (PM) fusion during exocytosis prior to and possibly during SNARE complex formation. Interestingly, it was recently implicated both in animals and plants in autophagy membrane traffic. In animal cells, the exocyst is integrated into the mTOR-regulated energy metabolism stress/starvation pathway, participating in the formation and especially initiation of an autophagosome. In plants, the first functional link was to autophagy-related anthocyanin import to the vacuole and to starvation. In this concise review, we summarize the current knowledge of exocyst functions in autophagy and defence in plants that might involve unconventional secretion and compare it with animal conditions. Formation of different exocyst complexes during undisturbed cell growth, as opposed to periods of cellular stress reactions involving autophagy, might contribute to the coordination of endomembrane trafficking pathways.
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Affiliation(s)
- Tamara Pecenková
- Laboratory of Cell Biology, Institute of Experimental Botany, Academy of Sciences of the Czech Republic, Czech Republic
- Laboratory of Cell Morphogenesis, Department of Experimental Plant Biology, Charles University in Prague, Faculty of Science, Czech Republic
| | - Vedrana Markovic
- Laboratory of Cell Biology, Institute of Experimental Botany, Academy of Sciences of the Czech Republic, Czech Republic
- Laboratory of Cell Morphogenesis, Department of Experimental Plant Biology, Charles University in Prague, Faculty of Science, Czech Republic
| | - Peter Sabol
- Laboratory of Cell Morphogenesis, Department of Experimental Plant Biology, Charles University in Prague, Faculty of Science, Czech Republic
| | - Ivan Kulich
- Laboratory of Cell Morphogenesis, Department of Experimental Plant Biology, Charles University in Prague, Faculty of Science, Czech Republic
| | - Viktor Žárský
- Laboratory of Cell Biology, Institute of Experimental Botany, Academy of Sciences of the Czech Republic, Czech Republic
- Laboratory of Cell Morphogenesis, Department of Experimental Plant Biology, Charles University in Prague, Faculty of Science, Czech Republic
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29
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Atsmon-Raz Y, Tieleman DP. Parameterization of Palmitoylated Cysteine, Farnesylated Cysteine, Geranylgeranylated Cysteine, and Myristoylated Glycine for the Martini Force Field. J Phys Chem B 2017; 121:11132-11143. [PMID: 29144135 DOI: 10.1021/acs.jpcb.7b10175] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Peripheral membrane proteins go through various post-translational modifications that covalently bind fatty acid tails to specific amino acids. These post-translational modifications significantly alter the lipophilicity of the modified proteins and allow them to anchor to biological membranes. Over 1000 different proteins have been identified to date that require such membrane-protein interactions to carry out their biological functions, including members of the Src and Ras superfamilies that play key roles in cell signaling and carcinogenesis. We have used all-atom simulations with the CHARMM36 force field to parameterize four of the most common post-translational modifications for the Martini 2.2 force field: palmitoylated cysteine, farnesylated cysteine, geranylgeranylated cysteine, and myristoylated glycine. The parameters reproduce the key features of clusters of configurations of the different anchors in lipid membranes as well as the water-octanol partitioning free energies of the anchors, which are crucial for the correct reproduction of the expected biophysical behavior of peripheral membrane proteins at the membrane-water interface. Implementation in existing Martini setup tools facilitates the use of the new parameters.
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Affiliation(s)
- Yoav Atsmon-Raz
- Department of Biological Sciences, Centre for Molecular Simulation, University of Calgary , 2500 University Drive NW, Calgary, Alberta, Canada T2N 1N4
| | - D Peter Tieleman
- Department of Biological Sciences, Centre for Molecular Simulation, University of Calgary , 2500 University Drive NW, Calgary, Alberta, Canada T2N 1N4
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30
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MCC/Eisosomes Regulate Cell Wall Synthesis and Stress Responses in Fungi. J Fungi (Basel) 2017; 3:jof3040061. [PMID: 29371577 PMCID: PMC5753163 DOI: 10.3390/jof3040061] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 10/26/2017] [Accepted: 10/31/2017] [Indexed: 12/20/2022] Open
Abstract
The fungal plasma membrane is critical for cell wall synthesis and other important processes including nutrient uptake, secretion, endocytosis, morphogenesis, and response to stress. To coordinate these diverse functions, the plasma membrane is organized into specialized compartments that vary in size, stability, and composition. One recently identified domain known as the Membrane Compartment of Can1 (MCC)/eisosome is distinctive in that it corresponds to a furrow-like invagination in the plasma membrane. MCC/eisosomes have been shown to be formed by the Bin/Amphiphysin/Rvs (BAR) domain proteins Lsp1 and Pil1 in a range of fungi. MCC/eisosome domains influence multiple cellular functions; but a very pronounced defect in cell wall synthesis has been observed for mutants with defects in MCC/eisosomes in some yeast species. For example, Candida albicans MCC/eisosome mutants display abnormal spatial regulation of cell wall synthesis, including large invaginations and altered chemical composition of the walls. Recent studies indicate that MCC/eisosomes affect cell wall synthesis in part by regulating the levels of the key regulatory lipid phosphatidylinositol 4,5-bisphosphate (PI4,5P2) in the plasma membrane. One general way MCC/eisosomes function is by acting as protected islands in the plasma membrane, since these domains are very stable. They also act as scaffolds to recruit >20 proteins. Genetic studies aimed at defining the function of the MCC/eisosome proteins have identified important roles in resistance to stress, such as resistance to oxidative stress mediated by the flavodoxin-like proteins Pst1, Pst2, Pst3 and Ycp4. Thus, MCC/eisosomes play multiple roles in plasma membrane organization that protect fungal cells from the environment.
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31
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Rawat A, Brejšková L, Hála M, Cvrčková F, Žárský V. The Physcomitrella patens exocyst subunit EXO70.3d has distinct roles in growth and development, and is essential for completion of the moss life cycle. THE NEW PHYTOLOGIST 2017; 216:438-454. [PMID: 28397275 DOI: 10.1111/nph.14548] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Accepted: 02/24/2017] [Indexed: 05/28/2023]
Abstract
The exocyst, an evolutionarily conserved secretory vesicle-tethering complex, spatially controls exocytosis and membrane turnover in fungi, metazoans and plants. The exocyst subunit EXO70 exists in multiple paralogs in land plants, forming three conserved clades with assumed distinct roles. Here we report functional analysis of the first moss exocyst subunit to be studied, Physcomitrella patens PpEXO70.3d (Pp1s97_91V6), from the, as yet, poorly characterized EXO70.3 clade. Following phylogenetic analysis to confirm the presence of three ancestral land plant EXO70 clades outside angiosperms, we prepared and phenotypically characterized loss-of-function Ppexo70.3d mutants and localized PpEXO70.3d in vivo using green fluorescent protein-tagged protein expression. Disruption of PpEXO70.3d caused pleiotropic cell elongation and differentiation defects in protonemata, altered response towards exogenous auxin, increased endogenous IAA concentrations, along with defects in bud and gametophore development. During mid-archegonia development, an abnormal egg cell is formed and subsequently collapses, resulting in mutant sterility. Mutants exhibited altered cell wall and cuticle deposition, as well as compromised cytokinesis, consistent with the protein localization to the cell plate. Despite some functional redundancy allowing survival of moss lacking PpEXO70.3d, this subunit has an essential role in the moss life cycle, indicating sub-functionalization within the moss EXO70 family.
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Affiliation(s)
- Anamika Rawat
- Laboratory of Cell Morphogenesis, Department of Experimental Plant Biology, Faculty of Science, Charles University, Viničná 5, 128 44, Prague 2, Czech Republic
- Institute of Experimental Botany, Academy of Sciences of the Czech Republic, 165 02, Prague 6, Czech Republic
| | - Lucie Brejšková
- Laboratory of Cell Morphogenesis, Department of Experimental Plant Biology, Faculty of Science, Charles University, Viničná 5, 128 44, Prague 2, Czech Republic
- Institute of Experimental Botany, Academy of Sciences of the Czech Republic, 165 02, Prague 6, Czech Republic
| | - Michal Hála
- Laboratory of Cell Morphogenesis, Department of Experimental Plant Biology, Faculty of Science, Charles University, Viničná 5, 128 44, Prague 2, Czech Republic
- Institute of Experimental Botany, Academy of Sciences of the Czech Republic, 165 02, Prague 6, Czech Republic
| | - Fatima Cvrčková
- Laboratory of Cell Morphogenesis, Department of Experimental Plant Biology, Faculty of Science, Charles University, Viničná 5, 128 44, Prague 2, Czech Republic
| | - Viktor Žárský
- Laboratory of Cell Morphogenesis, Department of Experimental Plant Biology, Faculty of Science, Charles University, Viničná 5, 128 44, Prague 2, Czech Republic
- Institute of Experimental Botany, Academy of Sciences of the Czech Republic, 165 02, Prague 6, Czech Republic
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32
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Timr Š, Pleskot R, Kadlec J, Kohagen M, Magarkar A, Jungwirth P. Membrane Binding of Recoverin: From Mechanistic Understanding to Biological Functionality. ACS CENTRAL SCIENCE 2017; 3:868-874. [PMID: 28852701 PMCID: PMC5571466 DOI: 10.1021/acscentsci.7b00210] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Indexed: 06/07/2023]
Abstract
Recoverin is a neuronal calcium sensor involved in vision adaptation that reversibly associates with cellular membranes via its calcium-activated myristoyl switch. While experimental evidence shows that the myristoyl group significantly enhances membrane affinity of this protein, molecular details of the binding process are still under debate. Here, we present results of extensive molecular dynamics simulations of recoverin in the proximity of a phospholipid bilayer. We capture multiple events of spontaneous membrane insertion of the myristoyl moiety and confirm its critical role in the membrane binding. Moreover, we observe that the binding strongly depends on the conformation of the N-terminal domain. We propose that a suitable conformation of the N-terminal domain can be stabilized by the disordered C-terminal segment or by binding of the target enzyme, i.e., rhodopsin kinase. Finally, we find that the presence of negatively charged lipids in the bilayer stabilizes a physiologically functional orientation of the membrane-bound recoverin.
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Affiliation(s)
- Štěpán Timr
- Institute
of Organic Chemistry and Biochemistry, Czech
Academy of Sciences, Flemingovo nám. 2, 16610 Prague 6, Czech Republic
| | - Roman Pleskot
- Institute
of Organic Chemistry and Biochemistry, Czech
Academy of Sciences, Flemingovo nám. 2, 16610 Prague 6, Czech Republic
- Institute
of Experimental Botany, Czech Academy of
Sciences, Rozvojová
263, 16502 Prague
6, Czech Republic
| | - Jan Kadlec
- Institute
of Organic Chemistry and Biochemistry, Czech
Academy of Sciences, Flemingovo nám. 2, 16610 Prague 6, Czech Republic
| | - Miriam Kohagen
- Institute
of Organic Chemistry and Biochemistry, Czech
Academy of Sciences, Flemingovo nám. 2, 16610 Prague 6, Czech Republic
- Institute
for Computational Physics, University of
Stuttgart, Allmandring
3, Stuttgart, 70569, Germany
| | - Aniket Magarkar
- Institute
of Organic Chemistry and Biochemistry, Czech
Academy of Sciences, Flemingovo nám. 2, 16610 Prague 6, Czech Republic
- Faculty
of Pharmacy, University of Helsinki, Viikinkaari 5E, Helsinki, 00014 Finland
| | - Pavel Jungwirth
- Institute
of Organic Chemistry and Biochemistry, Czech
Academy of Sciences, Flemingovo nám. 2, 16610 Prague 6, Czech Republic
- Department
of Physics, Tampere University of Technology, P.O. Box 692, FI-33101 Tampere, Finland
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33
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Kampmeyer C, Karakostova A, Schenstrøm SM, Abildgaard AB, Lauridsen AM, Jourdain I, Hartmann-Petersen R. The exocyst subunit Sec3 is regulated by a protein quality control pathway. J Biol Chem 2017; 292:15240-15253. [PMID: 28765280 DOI: 10.1074/jbc.m117.789867] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Revised: 07/19/2017] [Indexed: 02/03/2023] Open
Abstract
Exocytosis involves fusion of secretory vesicles with the plasma membrane, thereby delivering membrane proteins to the cell surface and releasing material into the extracellular space. The tethering of the secretory vesicles before membrane fusion is mediated by the exocyst, an essential phylogenetically conserved octameric protein complex. Exocyst biogenesis is regulated by several processes, but the mechanisms by which the exocyst is degraded are unknown. Here, to unravel the components of the exocyst degradation pathway, we screened for extragenic suppressors of a temperature-sensitive fission yeast strain mutated in the exocyst subunit Sec3 (sec3-913). One of the suppressing DNAs encoded a truncated dominant-negative variant of the 26S proteasome subunit, Rpt2, indicating that exocyst degradation is controlled by the ubiquitin-proteasome system. The temperature-dependent growth defect of the sec3-913 strain was gene dosage-dependent and suppressed by blocking the proteasome, Hsp70-type molecular chaperones, the Pib1 E3 ubiquitin-protein ligase, and the deubiquitylating enzyme Ubp3. Moreover, defects in cell septation, exocytosis, and endocytosis in sec3 mutant strains were similarly alleviated by mutation of components in this pathway. We also found that, particularly under stress conditions, wild-type Sec3 degradation is regulated by Pib1 and the 26S proteasome. In conclusion, our results suggest that a cytosolic protein quality control pathway monitors folding and proteasome-dependent turnover of an exocyst subunit and, thereby, controls exocytosis in fission yeast.
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Affiliation(s)
- Caroline Kampmeyer
- From the Linderstrøm-Lang Center, Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen N, Denmark and
| | - Antonina Karakostova
- From the Linderstrøm-Lang Center, Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen N, Denmark and
| | - Signe M Schenstrøm
- From the Linderstrøm-Lang Center, Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen N, Denmark and
| | - Amanda B Abildgaard
- From the Linderstrøm-Lang Center, Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen N, Denmark and
| | - Anne-Marie Lauridsen
- From the Linderstrøm-Lang Center, Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen N, Denmark and
| | - Isabelle Jourdain
- the College of Life and Environmental Sciences, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter EX4 4QD, United Kingdom
| | - Rasmus Hartmann-Petersen
- From the Linderstrøm-Lang Center, Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen N, Denmark and
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34
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Vukašinović N, Oda Y, Pejchar P, Synek L, Pečenková T, Rawat A, Sekereš J, Potocký M, Žárský V. Microtubule-dependent targeting of the exocyst complex is necessary for xylem development in Arabidopsis. THE NEW PHYTOLOGIST 2017; 213:1052-1067. [PMID: 27801942 DOI: 10.1111/nph.14267] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Accepted: 09/13/2016] [Indexed: 05/23/2023]
Abstract
Cortical microtubules (MTs) play a major role in the patterning of secondary cell wall (SCW) thickenings in tracheary elements (TEs) by determining the sites of SCW deposition. The EXO70A1 subunit of the exocyst secretory vesicle tethering complex was implicated to be important for TE development via the MT interaction. We investigated the subcellular localization of several exocyst subunits in the xylem of Arabidopsis thaliana and analyzed the functional significance of exocyst-mediated trafficking in TE development. Live cell imaging of fluorescently tagged exocyst subunits in TE using confocal microscopy and protein-protein interaction assays were performed to describe the role of the exocyst and its partners in TE development. In TEs, exocyst subunits were localized to the sites of SCW deposition in an MT-dependent manner. We propose that the mechanism of exocyst targeting to MTs involves the direct interaction of exocyst subunits with the COG2 protein. We demonstrated the importance of a functional exocyst subunit EXO84b for normal TE development and showed that the deposition of SCW constituents is partially compromised, possibly as a result of the mislocalization of secondary cellulose synthase in exocyst mutants. We conclude that the exocyst complex is an important factor bridging the pattern defined by cortical MTs with localized secretion of the SCW in developing TEs.
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Affiliation(s)
- Nemanja Vukašinović
- Institute of Experimental Botany, v.v.i., The Czech Academy of Sciences, 16502, Prague 6, Czech Republic
- Department of Experimental Plant Biology, Faculty of Science, Charles University in Prague, 128 44, Prague 2, Czech Republic
| | - Yoshihisa Oda
- Center for Frontier Research, National Institute of Genetics, 1111 Yata, Mishima, Shizuoka, 411-8540, Japan
- Department of Genetics, School of Life Science, SOKENDAI (Graduate University for Advanced Studies), 1111 Yata, Mishima, Shizuoka, 411-8540, Japan
| | - Přemysl Pejchar
- Institute of Experimental Botany, v.v.i., The Czech Academy of Sciences, 16502, Prague 6, Czech Republic
| | - Lukáš Synek
- Institute of Experimental Botany, v.v.i., The Czech Academy of Sciences, 16502, Prague 6, Czech Republic
| | - Tamara Pečenková
- Institute of Experimental Botany, v.v.i., The Czech Academy of Sciences, 16502, Prague 6, Czech Republic
| | - Anamika Rawat
- Institute of Experimental Botany, v.v.i., The Czech Academy of Sciences, 16502, Prague 6, Czech Republic
- Department of Experimental Plant Biology, Faculty of Science, Charles University in Prague, 128 44, Prague 2, Czech Republic
| | - Juraj Sekereš
- Institute of Experimental Botany, v.v.i., The Czech Academy of Sciences, 16502, Prague 6, Czech Republic
- Department of Experimental Plant Biology, Faculty of Science, Charles University in Prague, 128 44, Prague 2, Czech Republic
| | - Martin Potocký
- Institute of Experimental Botany, v.v.i., The Czech Academy of Sciences, 16502, Prague 6, Czech Republic
| | - Viktor Žárský
- Institute of Experimental Botany, v.v.i., The Czech Academy of Sciences, 16502, Prague 6, Czech Republic
- Department of Experimental Plant Biology, Faculty of Science, Charles University in Prague, 128 44, Prague 2, Czech Republic
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Xu S, Zhang GY, Zhang H, Kitajima T, Nakanishi H, Gao XD. Effects of Rho1, a small GTPase on the production of recombinant glycoproteins in Saccharomyces cerevisiae. Microb Cell Fact 2016; 15:179. [PMID: 27769287 PMCID: PMC5073930 DOI: 10.1186/s12934-016-0575-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 10/03/2016] [Indexed: 11/14/2022] Open
Abstract
Background To humanize yeast N-glycosylation pathways, genes involved in yeast specific hyper-mannosylation must be disrupted followed by the introduction of genes catalyzing the synthesis, transport, and addition of human sugars. However, deletion of these genes, for instance, OCH1, which initiates hyper-mannosylation, could cause severe defects in cell growth, morphogenesis and response to environmental challenges. Results In this study, overexpression of RHO1, which encodes the Rho1p small GTPase, is confirmed to partially recover the growth defect of Saccharomyces cerevisiae Δalg3Δoch1 double mutant strain. In addition, transmission electron micrographs indicated that the cell wall structure of RHO1-expressed cells have an enhanced glucan layer and also a recovered mannoprotein layer, revealing the effect of Rho1p GTPase on cell wall biosynthesis. Similar complementation phenotypes have been confirmed by overexpression of the gene that encodes Fks2 protein, a catalytic subunit of a 1,3-β-glucan synthase. Besides the recovery of cell wall structure, the RHO1-overexpressed Δalg3Δoch1 strain also showed improved abilities in temperature tolerance, osmotic potential and drug sensitivity, which were not observed in the Δalg3Δoch1-FKS2 cells. Moreover, RHO1 overexpression could also increase N-glycan site occupancy and the amount of secreted glycoproteins. Conclusions Overexpression of RHO1 in ‘humanized’ glycoprotein producing yeasts could significantly facilitate its future industrial applications for the production of therapeutic glycoproteins. Electronic supplementary material The online version of this article (doi:10.1186/s12934-016-0575-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Sha Xu
- School of Biotechnology, Key Laboratory of Glycobiology and Biotechnology, Ministry of Education, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, Jiangsu, China.,State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214122, Jiangsu, China
| | - Ge-Yuan Zhang
- School of Biotechnology, Key Laboratory of Glycobiology and Biotechnology, Ministry of Education, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, Jiangsu, China
| | - Huijie Zhang
- School of Biotechnology, Key Laboratory of Glycobiology and Biotechnology, Ministry of Education, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, Jiangsu, China
| | - Toshihiko Kitajima
- School of Biotechnology, Key Laboratory of Glycobiology and Biotechnology, Ministry of Education, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, Jiangsu, China
| | - Hideki Nakanishi
- School of Biotechnology, Key Laboratory of Glycobiology and Biotechnology, Ministry of Education, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, Jiangsu, China
| | - Xiao-Dong Gao
- School of Biotechnology, Key Laboratory of Glycobiology and Biotechnology, Ministry of Education, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, Jiangsu, China. .,State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214122, Jiangsu, China.
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36
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Junková P, Prchal J, Spiwok V, Pleskot R, Kadlec J, Krásný L, Hynek R, Hrabal R, Ruml T. Molecular aspects of the interaction between Mason-Pfizer monkey virus matrix protein and artificial phospholipid membrane. Proteins 2016; 84:1717-1727. [PMID: 27578150 DOI: 10.1002/prot.25156] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Revised: 08/04/2016] [Accepted: 08/25/2016] [Indexed: 11/09/2022]
Abstract
The Mason-Pfizer monkey virus is a type D retrovirus, which assembles its immature particles in the cytoplasm prior to their transport to the host cell membrane. The association with the membrane is mediated by the N-terminally myristoylated matrix protein. To reveal the role of particular residues which are involved in the capsid-membrane interaction, covalent labelling of arginine, lysine and tyrosine residues of the Mason-Pfizer monkey virus matrix protein bound to artificial liposomes containing 95% of phosphatidylcholine and 5% phosphatidylinositol-(4,5)-bisphosphate (PI(4,5)P2 ) was performed. The experimental results were interpreted by multiscale molecular dynamics simulations. The application of these two complementary approaches helped us to reveal that matrix protein specifically recognizes the PI(4,5)P2 molecule by the residues K20, K25, K27, K74, and Y28, while the residues K92 and K93 stabilizes the matrix protein orientation on the membrane by the interaction with another PI(4,5)P2 molecule. Residues K33, K39, K54, Y66, Y67, and K87 appear to be involved in the matrix protein oligomerization. All arginine residues remained accessible during the interaction with liposomes which indicates that they neither contribute to the interaction with membrane nor are involved in protein oligomerization. Proteins 2016; 84:1717-1727. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- P Junková
- Department of Biochemistry and Microbiology, University of Chemistry and Technology, Prague, Czech Republic.
| | - J Prchal
- Department of Biochemistry and Microbiology, University of Chemistry and Technology, Prague, Czech Republic
| | - V Spiwok
- Department of Biochemistry and Microbiology, University of Chemistry and Technology, Prague, Czech Republic
| | - R Pleskot
- Laboratory of Cell Biology, Institute of Experimental Botany, Academy of Sciences of the Czech Republic, Prague, Czech Republic.,Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - J Kadlec
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - L Krásný
- Laboratory of molecular structure characterisation, Institute of Microbiology of the ASCR, Academy of Sciences of the Czech Republic, Prague, Czech Republic.,Department of Cancer Biology, Institute of Cancer Research, London, United Kingdom
| | - R Hynek
- Department of Biochemistry and Microbiology, University of Chemistry and Technology, Prague, Czech Republic
| | - R Hrabal
- Department of Biochemistry and Microbiology, University of Chemistry and Technology, Prague, Czech Republic
| | - T Ruml
- Department of Biochemistry and Microbiology, University of Chemistry and Technology, Prague, Czech Republic
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37
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Vukašinović N, Žárský V. Tethering Complexes in the Arabidopsis Endomembrane System. Front Cell Dev Biol 2016; 4:46. [PMID: 27243010 PMCID: PMC4871884 DOI: 10.3389/fcell.2016.00046] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 05/02/2016] [Indexed: 12/30/2022] Open
Abstract
Targeting of endomembrane transport containers is of the utmost importance for proper land plant growth and development. Given the immobility of plant cells, localized membrane vesicle secretion and recycling are amongst the main processes guiding proper cell, tissue and whole plant morphogenesis. Cell wall biogenesis and modification are dependent on vectorial membrane traffic, not only during normal development, but also in stress responses and in plant defense against pathogens and/or symbiosis. It is surprising how little we know about these processes in plants, from small GTPase regulation to the tethering complexes that act as their effectors. Tethering factors are single proteins or protein complexes mediating first contact between the target membrane and arriving membrane vesicles. In this review we focus on the tethering complexes of the best-studied plant model—Arabidopsis thaliana. Genome-based predictions indicate the presence of all major tethering complexes in plants that are known from a hypothetical last eukaryotic common ancestor (LECA). The evolutionary multiplication of paralogs of plant tethering complex subunits has produced the massively expanded EXO70 family, indicating a subfunctionalization of the terminal exocytosis machinery in land plants. Interpretation of loss of function (LOF) mutant phenotypes has to consider that related, yet clearly functionally-specific complexes often share some common core subunits. It is therefore impossible to conclude with clarity which version of the complex is responsible for the phenotypic deviations observed. Experimental interest in the analysis of plant tethering complexes is growing and we hope to contribute with this review by attracting even more attention to this fascinating field of plant cell biology.
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Affiliation(s)
- Nemanja Vukašinović
- Laboratory of Cell Morphogenesis, Department of Experimental Plant Biology, Faculty of Science, Charles University Prague, Czech Republic
| | - Viktor Žárský
- Laboratory of Cell Morphogenesis, Department of Experimental Plant Biology, Faculty of Science, Charles University Prague, Czech Republic
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38
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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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Pöyry S, Vattulainen I. Role of charged lipids in membrane structures - Insight given by simulations. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:2322-2333. [PMID: 27003126 DOI: 10.1016/j.bbamem.2016.03.016] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Revised: 03/09/2016] [Accepted: 03/11/2016] [Indexed: 01/28/2023]
Abstract
Lipids and proteins are the main components of cell membranes. It is becoming increasingly clear that lipids, in addition to providing an environment for proteins to work in, are in many cases also able to modulate the structure and function of those proteins. Particularly charged lipids such as phosphatidylinositols and phosphatidylserines are involved in several examples of such effects. Molecular dynamics simulations have proved an invaluable tool in exploring these aspects. This so-called computational microscope can provide both complementing explanations for the experimental results and guide experiments to fruitful directions. In this paper, we review studies that have utilized molecular dynamics simulations to unravel the roles of charged lipids in membrane structures. We focus on lipids as active constituents of the membranes, affecting both general membrane properties as well as non-lipid membrane components, mainly proteins. This article is part of a Special Issue entitled: Biosimulations edited by Ilpo Vattulainen and Tomasz Róg.
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Affiliation(s)
- Sanja Pöyry
- Department of Physics, Tampere University of Technology, POB 692, FI-33101 Tampere, Finland
| | - Ilpo Vattulainen
- Department of Physics, Tampere University of Technology, POB 692, FI-33101 Tampere, Finland; MEMPHYS - Center for Biomembrane Physics, University of Southern Denmark, Odense, Denmark; Department of Physics, University of Helsinki, POB 64, FI-00014 Helsinki, Finland.
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40
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Douglas LM, Konopka JB. Plasma membrane organization promotes virulence of the human fungal pathogen Candida albicans. J Microbiol 2016; 54:178-91. [PMID: 26920878 DOI: 10.1007/s12275-016-5621-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Revised: 01/15/2016] [Accepted: 01/15/2016] [Indexed: 12/21/2022]
Abstract
Candida albicans is a human fungal pathogen capable of causing lethal systemic infections. The plasma membrane plays key roles in virulence because it not only functions as a protective barrier, it also mediates dynamic functions including secretion of virulence factors, cell wall synthesis, invasive hyphal morphogenesis, endocytosis, and nutrient uptake. Consistent with this functional complexity, the plasma membrane is composed of a wide array of lipids and proteins. These components are organized into distinct domains that will be the topic of this review. Some of the plasma membrane domains that will be described are known to act as scaffolds or barriers to diffusion, such as MCC/eisosomes, septins, and sites of contact with the endoplasmic reticulum. Other zones mediate dynamic processes, including secretion, endocytosis, and a special region at hyphal tips that facilitates rapid growth. The highly organized architecture of the plasma membrane facilitates the coordination of diverse functions and promotes the pathogenesis of C. albicans.
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Affiliation(s)
- Lois M Douglas
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, NY, 11794-5222, USA
| | - James B Konopka
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, NY, 11794-5222, USA.
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